Vickers. CMX Sectional Controls. Directional Controls. Application Guide. Revised 3/95

Transcription

1 Vickers Directional Controls CMX Sectional Controls Alication Guide Revised 3/95 536

2 Third generation closed center load sensing is here...today Additional assistance with your CMX valve requireents is as near as your local Vickers distributor. With Vickers EZSec CMX Progra, which incororates the use of re-engineered coonents, he can quickly design, rice, asseble, test, and shi valve banks that satisfy the requireents of ost alications.

3

4 General Descrition The CMX sectional valve is a stackable, load sensing, roortional directional control valve, and can be oerated by hydraulic reote control (HRC) or electronic reote control (ERC) via integral electrohydraulic reducing valves. A characteristic feature of the CMX valve line is the concet of searate eter-in and eter-out eleents (Figure 1). The eter-in eleent is a ilot oerated, flow force, ressure coensated, roortional sliding sool and controls fluid fro the u to the actuator. The eter-out eleents are ilot controlled etering oets, and control exhaust fluid fro the actuator to tank. Each eter-out oet functions as a variable orifice between one of the actuator s orts and the tank ort, with the degree of oening roortional to the ilot signal. A CMX valve bank is ade u of an inlet body, fro one to eight valve sections, and an end cover (Figure 2). The valve sections are connected internally to coon ressure, tank, load sense, ilot suly and ilot drain assages. Face seals between the sections seal the connecting assages, and the sections are held together by tie rods and nuts. Threaded ounting bolt holes are rovided on the inlet body and end cover. The u, tank, load sense and electrohydraulic ilot suly assages are terinated in the inlet body, and the ilot drain is terinated in the end cover. Connections for the actuator and the HRC are ade at each section. Electrical connections for electrohydraulic valves are ade at each coil. HRC and ERC controlled valves can be used in the sae valve bank. The searation of the eter-in and eter-out eleents, lus the valve s odular design, erits a broad range of control otions to eet a variety of load requireents. This is esecially desirable for a stackable obile valve, where a single valve bank ust handle any different functions. The CMX sectional valve faily consists of two basic series with different flow ratings the CMX1 and the CMX16. These valves are functionally identical, with ost differences being due to the differences in their hysical size. Figure 2

5 Oerating Valve Section The CMX valve section consists of three basic arts: the ain valve body, which contains the ain flow assages and ain control eleents, and two control cas that contain the ilot circuitry. The one-iece control ca gaskets (Figure 3), which rovide a seal between the control cas and the ain valve body, are also art of the ilot circuit, roviding a assage fro the eter-in sring chaber to the relief valve ilot stage and the eter-out servo. This forat allows for a wide variety of control otions fro relatively few basic arts; thus the valve can be tailored to the alication at inial extra cost. It also akes the valve quick and easy to fine tune for a secific alication. Flow Path/Actuation Hydraulically Actuated (Refer to following age.) When ilot ressure is alied to Port C1, u flow is to Port B. When ilot ressure is alied to Port C2, u flow is to Port A. Electrohydraulically Actuated (Click here for illustrations.) When Solenoid A is energized, u flow is to Port A. When Solenoid B is energized, u flow is to Port B. Control Ca Gasket Pilot relief valve (electrohydraulic odels) Meter-in sring chaber Meter-out servo Drain Pilot relief valve (hydraulic odels) Figure 3 Electrohydraulic ilot sool Restriction (orifice) Pilot suly assage (electrohydraulic odels)

6 Oerating Valve Section Cutaway views of the hydraulic and electrohydraulic versions of the CMX are shown in Figures 4 and 5, along with scheatic diagras. The relief valve ilot stages are shown in detail in the scheatic diagras used in this discussion to roote a better understanding of the valve s oeration. Hydraulic Valve Section Actuator Port A Meter-out Poet Return Port Actuator Port B Control Ca Load Sensing Check Valves Load Dro Check Pilot Relief Pilot Pressure Port C1 Pilot Pressure Port C2 Vent Meter-in Sool Meter-in Chabers Valve Inlet Port Gasket B A C1 C2 DR T LS P DR Figure 4

7 Electrohydraulic Valve Section Electrohydraulic Reducing Valve Sool Meter-out Poet Adjustable Relief (otional) Actuator Port A Return Port Actuator Port B Load Dro Check Pilot Relief (As shown in Figure 4, receding age.) A Solenoid B Solenoid Load Sensing Check Valves Vent Meter-in Sool Valve Inlet Port Meter-in Chabers Gasket Pilot Suly Passages B A Sol. B Sol. A T DR PS LS P PS DR Figure 5

8 Oerating Valve Section The ain valve body is available as a narrow body with an actuator ort ressure rating of 29 bar (42 si) and an inlet ort ressure rating 25 bar (3625 si), or as a wide body with an actuator ort ressure rating of 38 bar (551 si) and an inlet ort ressure rating of 35 bar (575 si). Valve sections with different ressure ratings can be used in the sae valve bank. Valve section sizes and ratings are shown below. Click here for ort and ounting hole sizes. Valve Section Sizes CMX1-S2 (narrow body and 29 bar (42 si) rating) Hydraulic Actuation - Diensions: 21 (7.9 in) long x 47, (1.85 in) wide x 149 (5.87 in) high. Weight: 7,3 kg (16.2 lbs) Electrohydraulic Actuation - Diensions: 366 (14.4 in) long x 47, (1.85 in) wide x 149 (5.87 in) high. Weight: 9, kg (19.8 lbs) CMX1-F2 (wide body and 38 bar (551 si) rating) Hydraulic Actuation - Diensions: 21 (7.9 in) long x 59, (2.32 in) wide x 144 (5.67 in) high. Weight: 8,7 kg (19.2 lbs) Electrohydraulic Actuation - Diensions: 366 (14.4 in) long x 59, (2.32 in) wide x 144 (5.67 in) high. Weight: 1,4 kg (22.8 lbs) CMX16-S2 (narrow body and 29 bar (42 si) rating) Hydraulic Actuation - Diensions: 243 (9.6 in) long x 51, (2.1 in) wide x 172 (6.77 in) high. Weight: 1,2 kg (22.5 lbs) Electrohydraulic Actuation - Diensions: 386 (15.2 in) long x 51, (2.1 in) wide x 172 (6.77 in) high. Weight: 11,8 kg (26.1 lbs) CMX16-F2 (wide body and 38 bar (551 si) rating) Hydraulic Actuation - Diensions: 243 (9.6 in) long x 75, (2.95 in) wide x 165 (6.5 in) high. Weight: 13,4 kg (29.6 lbs) Electrohydraulic Actuation - Diensions: 386 (15.2 in) long x 75, (2.95 in) wide x 165 (6.5 in) high. Weight: 15,1 kg (33.2 lbs) Notes: Diensions and weights for G and W sections are identical to F sections. Click here for ort diensions. Click here for valve bank diensions. * At 14 bar (2 si) load-sensing ressure dro.

9 The oerating eleents in the CMX sectional valve can be divided into five functional grous: eter-in, eter-out, load dro check valves, load sense check valves and relief valve ilot stages. The electrohydraulic version includes additional solenoid oerated roortional reducing valves to rovide ilot control ressure. Each functional grou is described in the following ages. Meter-in eleent The eter-in eleent orts fluid fro the valve inlet ort to the A or B eter-in chaber. The eter-in eleent is a ilot oerated, sring centered, roortional sliding sool. The inlet ort is closed in neutral. Two different srings are available to rovide different eter-in cracking ressures (the ilot ressure required to begin flow fro the inlet to an actuator ort). The area gain (or sloe of the etering curve) is the sae for both srings. The eter-in eleent is available as a flow control tye (S***) or a ressure control tye (S***). Low flow sool otions are available for both the flow control eter-in eleent (L***) and the ressure control eter-in eleent (L***). The low flow otion rovides finer etering and lower flow caability than the standard S*** sool for functions where the full flow caability of the valve is not desired. Low flow sools are available for the CMX1 only. Flow control eter-in eleents S* and L* The flow control eleent (shown on the following age) rovides nearly constant flow for a given coand signal, indeendent of ressure dro across the eter-in sool and indeendent of load ressure. Flow is roortional to coand ilot ressure differential. Pressure coensation, which is achieved by utilizing flow forces, iniizes load interaction caused by the siultaneous oeration of ore than one function. In the standard vented sool, fluid asses through an orifice to the center of the sool to the ilot ressure orts, where it is drained to tank via the HRC (hydraulic ilot odels) or the reducing valve (electrohydraulic odels). Ball check valves revent reverse flow through the vent when ilot ressure is alied to sools.

10 Oerating Valve Section Coand Port C1 Sring Meter-in Chabers Pilot Suly Thru Holes Vent Coand Port C2 Meter-in Sool Inlet Ball Check Standard (SD) Model B A C1 C2 Check Valves For Vented Meter-in Sool T DR PS LS P PS DR Non-vented (SN) Model B A C1 C2 Meter-in Eleent T DR PS LS P PS DR Figure 6

11 CMX Meter-In Flow vs. Coand at 2 bar P-LS Pressure Differential si l 15 1 CMX16 S*O** CMX1 S*O** CMX1 L*O** 6 SPRING g SPRING Coand Pressure, bar (12V coil) Coand (24V coil) Currrent, A

12 Oerating Valve Section CMX1 Meter-In Pressure Coensation Model S6 Meter-in Eleent 2 15 l 1 5 si Pressure Dro (P LS), bar Figure 8a Coand Pressure 22 bar (319 si) 2 bar (29 si) 18 bar (261 si) 16 bar (232 si) 14 bar (23 si) 12 bar (174 si) 1 bar (145 si) 8 bar (116 si) g CMX1 Meter-In Pressure Coensation Model S12 Meter-in Eleent 2 15 l 1 5 si Pressure Dro (P LS), bar Figure 8b Coand Pressure 28 bar (46 si) 26 bar (377 si) 24 bar (348 si) 22 bar (319 si) 2 bar (29 si) 18 bar (261 si) 16 bar (232 si) 14 bar (23 si) g

13 Oerating Valve Section CMX1 Low Flow M-I Pressure Coensation Model L6 Meter-in Eleent 2 si l 1 Coand Pressure 3 g 2 2 bar (29 si) bar (145 si) Pressure Dro (P-LS), bar Figure 8c

14 Oerating Valve Section CMX16 Meter-In Pressure Coensation (Flow Force Coensation) Model S6 Meter-in Eleent si l 2 1 CMX16 Meter-In Pressure Coensation (Flow Force Coensation) Model S12 Meter-in Eleent Coand Pressure 22 bar (319 si) 2 bar (29 si) 18 bar (261 si) 16 bar (232 si) 14 bar (23 si) 12 bar (174 si) 1 bar (145 si) 8 bar (116 si) Pressure Dro (P LS), bar si g l 2 1 Coand Pressure 26 bar (377 si) 24 bar (348 si) 2 bar (29 si) 16 bar (232 si) g 12 bar (174 si) Pressure Dro (P LS), bar

15 Oerating Valve Section Pressure control eter-in eleent S**** This eleent (Figure 1) is siilar to the flow control eleent, excet the ressure control sool has a feedback iston on each end. The eter-in chaber ressure acts on the area of the iston and ooses the ilot ressure oening the sool. The result is that, for a given inut signal (ilot ressure), the flow decreases as the load ressure increases until the axiu ressure is reached at zero flow. By changing the inut signal, the axiu load ressure can be changed. For a constant load ressure, changing the inut signal will change the velocity of the load. This feature rovides the oerator with a good feel for the syste by resonding to changes in load ressure. For exale, when driving a load at a given seed, if an obstacle is encountered, the load will slow or even sto. This resonse, which is tyical of traditional oen center byass control valves, gives the oerator better control of the syste. The ressure control sool also increases the syste daing ratio, which affects syste stability and resonse. By selecting the aroriate feedback iston size (diaeter), the syste daing ratio can be tailored to the alication. (Click here for feedback iston diaeters in the odel code.) The larger the feedback iston, the greater the increase in the daing ratio due to the ressure control sool. The ressure-flow relationshi is shown in the Q-P diagras on the following three ages. The sloe of the constant-ilot-ressure lines is deendent on feedback iston diaeter. The flow is indeendent of load ressure at zero load ressure, so a constant ilot ressure line will intercet the Q axis at the sae oint, regardless of its sloe. The eter-in chabers are drained by an orifice to the ilot ressure orts in a anner siilar to the S*** flow control sool. Meter in chabers Coand ort C1 Inlet Coand ort C2 Feedback iston Sring Meter in sool Vent C1 C2 P Figure 1

16 Oerating Valve Section CMX1 Meter-In Pressure Control Sool Pressure vs. Flow Model S26 Meter-in Eleent g b a r Flow, l Coand Pressure 22 bar (319 si) CMX1 Meter-In Pressure Control Sool Pressure vs. Flow Model S46 Meter-in Eleent g Coand Pressure bar (116 si) 12 bar (174 si) 16 bar (232 si) 2 bar (29 si) 18 bar (261 si) 34 bar (MAX.) 32 bar (464 si) k s i b a r bar (48 si) 3 2 k s i bar (116 si) 12 bar (174 si) 16 bar (232 si) Flow, l 24 bar (348 si) 2 bar (29 si) 1

17 Oerating Valve Section CMX16 Meter-In Pressure Control Sool Pressure vs. Flow Model S26 Meter-in Eleent g Coand Pressure 5 4 b a r bar (319 si) 3 2 k s i bar 12 bar 16 bar (116 si) (174 si) (232 si) Flow, l 1 2 bar (29 si) 2 25 CMX16 Meter-In Pressure Control Sool Pressure vs. Flow Model S46 Meter-in Eleent g bar (464 si) 4 25 Coand Pressure b a r bar (46 si) 3 2 k s i bar (116 si) 12 bar (174 si) 16 bar (232 si) Flow, l 2 bar (29 si) 24 bar (348 si)

18 Oerating Valve Section CMX16 Meter-In Pressure Control Eleent Pressure vs. Flow Model S56 eter-in eleent 35 g Coand Pressure bar (Max.) 4 b a r bar (46 si) 28 bar (46 si) 3 2 k s i bar (116 si) 12 bar (174 si) 16 bar (232 si) 2 bar (29 si) 24 bar (348 si) 5 1 Flow, l Figure 12c

19 Oerating Valve Section S*** sool ressure coensation The ressure control sool is ressure coensated by flow forces to rovide constant flow indeendent of suly ressure, to iniize function interference. Since the sool does resond to load ressure and the ressure coensation curve is not erfectly flat, changes in load ressure will cause slight changes in the ressure flow relationshi, as shown below (Figure 13). CMX1 Meter-In Pressure Coensation Model S46 eter-in eleent si Coand Pressure 5 2 bar (29 si) (4 bar P LS diff.) 4 35 l 3 (2 bar P LS diff.) 1 25 (2 bar P LS diff.) 2 g Pressure Dro (P LS), bar CMX1 Meter-In Pressure Control Sool Model S46 eter-in eleent g (4 bar P LS diff.) Coand Pressure 2 bar (29 si) 5 4 b a r 2 15 (2 bar P LS diff.) 3 2 k s i 1 5 (2 bar P LS diff.) Flow, l 1

20 Oerating Valve Section Flow liitation orifice Flow to a work function can be liited by the installation of a restricting orifice in the u suly ort of the valve section. Since the orifice will restrict flow to all sections downstrea, its use is norally liited to the last valve in a bank. The orifice is only effective if the liited flow function is the highest ressure function for the u. The orifice reduces the ressure dro across the eter-in eleent, while the u aintains a constant ressure differential between ressure and load sensing. The flow liitation orifice is available as a secial order only. CMX16 Meter-In Pressure Control Eleent 5.5 Dia. Flow Liitation Orifice Model S56 Meter-in Eleent 35 g bar (348 si) 28 bar (46 si) Coand Pressure 4 b a r bar (232 si) 2 bar (29 si) 3 2 k s i bar (116 si) 12 bar (174 si) Flow, l P LS Pressure Differential = 2 bar constant 1

21 Oerating Valve Section Meter-In Flow Liitation Orifice Selection Chart Maxiu Flow vs. Inlet Orifice Diaeter g CMX1 CMX16 1 bar 15 bar 2 bar 25 bar i n Maxiu Flow, l

22 Oerating Valve Section Load sensing check valves standard design The -25 design CMX sectional valves are equied with load sense check valves (Figure 15) that are different fro the load sense shuttle valves rovided on earlier odels. The function of the load sense check valves is to suly the highest active load ressure to the load sense assage, while isolating lower ressure eter-in chabers fro the load sense assage. The load dro check valves revent the load ressure fro overrunning loads or inactive (neutral) sections fro reaching the eter-in chabers. When one or ore of the sections in a valve bank is energized, the highest eter-in ressure is resented to the load sense ort, which in turn controls the u outut ressure. The load sensing us sulied by Vickers norally roduce an outut ressure between 13.8 bar (2 si) and 41.4 bar (6 si) above the load sense ressure. When all the sections are centered (or whenever the eter-in load sense signal decreases), all the load sense check valves close, traing fluid in the load sense assage. A rovision to vent this traed fluid ust be rovided to allow the load sense signal to decay and the u outut ressure to return to standby. Valve bank end covers are available with a rovision to vent the load sense ort to drain. Click here to see odel code.

23 Oerating Valve Section On systes which utilize the.5 bleed orifice, it is recoended for otiu erforance that the orifice be located at the end of the valve bank oosite the u connection. On ultile valve bank systes, the load sense connections should be ade in series, with the orifice located as far fro the u as ossible. On id inlet valve banks, the load sense-to-u connection should be ade at one end cover, and the bleed orifice located at the oosite end cover. The reasons for the above recoendations are as follows: Flow in the load sense assage to the load sense bleed orifice causes a ressure dro through each section. The cuulative effect of the ressure dro through each section can be significant, esecially at higher load sense ressures, higher fluid viscosities, and when any sections are resent. The higher load sense ressures cause a higher bleed flow rate, and higher fluid viscosities (such as cold oil) cause a higher ressure dro. If the bleed flow is toward the u load sense ort (Figure 16b), the ressure dro subtracts fro the load sense signal. For exale, assue a 2 bar (29 si) load, and a u load sense setting of 13.8 bar (2 si). When the valve is energized, the 2 bar is resented to the load sense assage. If flow to the bleed orifice causes a ressure loss of.7 bar (1 si) er section, and there are eight sections between the valve and the u, then the u will sense a load sense signal of bar (282 si), and aintain an outut ressure of = 28.2 bar, which is only 8.2 bar (119 si) above the load ressure. The result will be slower oeration for that function. If the bleed flow is away fro the u load sense (Figure 16a), then the actual load sense ressure is sulied to the u without flow induced ressure losses, and consistent erforance can be achieved.

24 Oerating Valve Section Load dro check valves standard The load dro check valves (Figure 17) isolate the eter in sool and the load sense check valves fro the actuator orts. This feature akes it ossible to aintain very low cylinder ort leakage indeendent of eter-in sool-to-bore clearance. Therefore, eter-in sool-to-bore clearances are relatively large, iniizing hysteresis and aking eter-in sools fully interchangeable. Bleed orifice Certain alications, such as brake release circuits and counterbalance circuits, require low actuator ort ressure to be aintained in neutral. Load dro check valves with a bleed orifice are available to vent fluid traed in the actuator orts to the eter-in chabers. This feature requires a eter-in eleent with drain orifices and is available as a secial order only. Meter in chaber Passage to actuator ort A Bleed orifice (when req d) Load sense check valve Meter in chaber Load dro check valve oet Passage to actuator ort B Sring Retainer Meter in sool Load dro check valve B A

25 Oerating Valve Section CMX Sectional Valve Load Dro Check Flow vs. Pressure Dro g CMX16 2 b a r 1 CMX s i d Flow, l

26 Oerating Valve Section Meter-out eleents Meter-out control is achieved by using a ilot oet-ste along with a odulating eter-out oet to for a sile hydroechanical bleed servo (Figure 19). Actuator ort ressure acts on the annular differential area between the ajor outside diaeter of the eter-out oet and the eter-out oet skirt (or seat) diaeter, and tends to ush the eter-out oet oen. The ressure in the sring chaber acts on the full ajor O.D. area of the eter-out oet, and tends to close the eter-out oet. When the eter-out eleent is closed, the ressure in the sring chaber is equalized to actuator ort ressure via a.75 (.3 in.) orifice in the eter-out oet. Since the ressure in the sring chaber is only artially offset by the actuator ort ressure acting on the annular area, the eter-out oet reains closed rovided tank ressure is below actuator ort ressure. To oen the eter-out oet, ilot ressure alied to the eter-in sring chaber is transitted by a assage in the control ca gasket to the eter-out iston. The force against the eter out iston oves the oet-ste fro its seat and against the oosing sring, oening a assage fro the eter-out sring chaber to the tank assage. Fluid then asses fro the actuator ort through the orifice in the eter-out oet to the sring chaber and then to tank. This flow develos a ressure differential across the orifice in the eter-out oet, which subtracts fro the actuator ort ressure, reducing the eter-out sring chaber ressure. When the ressure in the eter-out sring chaber falls low enough, the actuator ort ressure acting on the annular area will overcoe the eter-out sring chaber ressure and oen the eter-out oet, oving it toward the oet ste. This otion will tend to close the oet-ste against its seat, reducing the flow-induced ressure dro across the orifice and increasing the ressure in the eter-out sring chaber. Meter-out eleent B A T DR PS LS P PS DR Figure 19. The eter-out eleent is not ressure coensated, so interaction robles with the eter-in eleent are avoided.

27 Oerating Valve Section The eter-out oet will assue a osition where the oet ste-to-seat restriction is such that the reduced ressure in the eter-out sring chaber balances the forces on the eter-out oet. The net effect is that the eter-out oet follows the oet-ste osition. The oveent of the oet-ste is controlled only by the ilot signal and the sring it oves against. The osition feedback gain of the eter-out oet is high, so a sall change in osition of the eter-out oet away fro the balanced-force osition results in a large increase in forces acting to return the eter-out oet to the balanced-force osition. These forces are high coared to flow forces, so the eter-out oet will not close reaturely due to flow forces. Several different eter-out oets are available which rovide different area gains. A high gain oet (low P at rated flow) rovides better control when lowering a light load. A low gain oet (high P at rated flow) rovides better control when lowering heavy loads. Meter-out oets are rated according to the actuator ort to tank ressure dro in bar across the oet at the valve s rated flow with the oet fully oened. Perforance data is shown below and on the following three ages. CMX1 Meter-out Flow vs. Coand S3 (3 bar) Meter-out High Gain Poet si bar (145 si) 5 bar (725 si) 6 2 l 15 1 Pressure Dro (actuator ort to tank) 2 bar (29 si) 1 bar (145 si) g Coand Pressure, bar

28 Oerating Valve Section CMX1 Meter-out Flow vs. Coand S14 (14 bar) Meter-out Mediu Gain Poet 25 si Pressure Dro (actuator ort to tank) 2 bar (29 si) 1 bar (145 si) 6 l bar (725 si) 2 bar (29 si) 1 bar (145 si) g Coand Pressure, bar Figure 2b CMX1 Meter-out Flow vs. Coand S9 (9 bar) Meter-out Low Gain Poet 25 2 si Pressure Dro (actuator ort to tank) 35 bar (575 si) 6 5 l bar (29 si) 1 bar (145 si) 5 bar (725 si) 2 bar (29 si) 1 bar (145 si) Coand Pressure, bar Figure 2c g

29 Oerating Valve Section CMX16 Meter-out Flow vs. Coand S4 (4 bar) Meter-out High Gain Poet si Pressure Dro (actuator ort to tank) 1 bar (145 si) 5 bar (725 si) 2 bar (29 si) l bar (145 si) g Coand Pressure, bar Figure 21a CMX16 Meter-out Flow vs. Coand S7 (7 bar) Meter-out High Gain Poet si l Pressure Dro (actuator ort to tank) 2 bar (29 si) 1 bar (145 si) 2 bar (29 si) 5 bar (725 si) g 1 1 bar (145 si) Coand Pressure, bar Figure 21b

30 Oerating Valve Section CMX16 Meter-out Flow vs. Coand S14 (14 bar) Meter-out Mediu Gain Poet si Pressure Dro (actuator ort to tank) 2 bar (29 si) 1 bar (145 si) 5 bar (725 si) l 2 2 bar (29 si) g 1 1 bar (145 si) Coand Pressure, bar CMX16 Meter-out Flow vs. Coand S56 (56 bar) Meter-out Low Gain Poet l si Pressure Dro 35 bar (actuator ort to tank) (575 si) 1 2 bar (29 si) bar (145 si) 5 bar (725 si) bar (29 si) bar (145 si) Coand Pressure, bar g

31 Oerating Valve Section Anticavitation check valves standard Cavitation rotection is norally rovided by reverse flow through the eter-out oets. In this ode, tank ressure above the actuator ort ressure, acting on the eter-out oet skirt area, oens the eter-out oet. Tank ressure is aintained by a back ressure check in the tank line. Perforance (flow vs. ressure dro) is shown in Figure 22 below and on the following age. For eter-out load ressures above 7 bar sufficient oentu exchange occurs, due to the high velocity jet fro an actuator ort exhausting fluid iinging uon the oosite eter-out oet, to cause the oosite actuator ort ressure to be higher than the tank ressure. This henoenon is fairly colex, since the oosite ort ressure is a function of the load ressure, load seed (or flow rate), the tank ort ressure, the area gains of both eter-out oets (oet tyes) and the cylinder area ratio. The following exale is illustrative: for a CMX16 lowering A to T a load of 138 bar (2 si), 16 l (42 USg), 1:1 area ratio, oen tank (no back ressure check valve), a tye 56 eter-out oet in the A ort, and a tye 7 oet in the B ort; the B ort ressure is 12.9 bar (187 si) and the tank ort ressure is.5 bar (7 si). For the sae conditions with a 2:1 area ratio, the B ort ressure would be 7.6 bar (11 si) and the tank ressure would be.7 bar (1 si). CMX1 Anti-Cavitation Check Valves Standard (Reverse Flow Thru M O Poets) Flow vs. Pressure Dro (T A) b a r 1 2 g \ 4 2 S3 Poet S14 Poet S9 Poet Flow, l s i

32 Oerating Valve Section CMX16 Anti-Cavitation Check Valves Standard (Reverse Flow Thru M O Poets) Flow vs. Pressure Dro (T A) g S4 Poet S7 Poet S14 Poet S56 Poet 5 4 b a r s i Flow, l

33 Oerating Valve Section The eter-out oet will reain closed when the tank ressure is above the actuator ort ressure and the eter-out servo is iloted oen. In this case, the oet-ste oens and fluid enters the sring chaber fro tank. The orifice in the eter-out oet restricts the flow leaving the sring chaber, so the sring chaber ressure is nearly equal to the tank ressure. Since the actuator ort ressure is lower than tank, the force on the annular area of the eter-out oet due to actuator ort ressure is less than the oosing force due to tank ressure in the sring chaber, and the eter-out oet closes and reains closed. Cavitation can occur under these conditions, which norally occur only if the float feature is used, or when reversing the direction of a oving load. (Click here for float feature.) Secial eter-out oets are available with check valves which revent reverse flow into the eter-out sring chaber and subsequent uncontrolled closing of the eter-out oet. (Not available for CMX16 7 and 56 M-O oets.) Anticavitation odule For alications that require inial back ressure in the tank ort, a bolt-on odule (Figure 23) is available that rovides anticavitation erforance suerior to the eter-out oet. This odule is only available on odels with the SAE 4-bolt flange. Modules are available with single and dual anti-cavitation check valves. Figure 24, on th folloeing age, shows tyical erforance data. Poet Sring Actuator ort A Tank Actuator ort B B A T DR PS LS P PS DR Module Figure 23

34 Oerating Valve Section CMX Anti-Cavitation Check Module Flow vs. Pressure Differential (T A) 3. g CMX1 CMX b a r 2 s i d Flow, l Figure 24

35 Oerating Valve Section CMX16 Float Perforance Flow vs. Pressure Dro (B A) Flow B T A (T Blocked) 4 g A Port Poet S14 B Port Poet S S14 S4 S4 S4 4 b a r 2 3 s i Flow, l Figure 25

36 Oerating Valve Section Meter-out sool A version of the CMX that relaces the eter-out oets with a sool is available. (Click here to see odel code.) This version does not rovide eter-out etering, load holding or relief valve rotection. This version can be used with counterbalance valve circuits. Two eter-out sool versions are available; one is oen in neutral, the other rovides restricted flow to tank in neutral. The restriction is equivalent to a.75 (.3 in.) orifice. Port A Port B Meter out sool B A T DR PS LS P PS DR Figure 26

37 Oerating Valve Section CMX1 Meter-out Sool Perforance Flow vs. Pressure Differential A-T Flow A T g M Sool (Center) M Sool (Shift) N Sool (Shift) b a r s i Flow, l NOTE: Centered sool alfunctions Figure 27a at flows above 2 l. CMX1 Meter-out Sool Perforance Flow vs. Pressure Differential A-B Flow A T B (T Blocked) g b a r M Sool (Center) s i Flow, l NOTE: Centered sool alfunctions Figure 27b at flows above 2 l.

38 Oerating Valve Section Actuator ort relief valve The actuator ort relief valve uses a ilot stage to rovide a ilot signal to the eter-out servo that, in turn, oens the eter-out oet to relieve fluid to tank. The relief valve ilot stage consists of a oet, seat and sring (Figure 28). When actuator ort ressure overcoes the relief valve sring force, the relief valve oet oves off its seat and fluid flows into the assage in the control ca gasket (on hydraulic odels, the relief valve oet seat is incororated into the load dro check retainer). Control ca Meter out iston Load dro check retainer Relief valve ilot stage oet Meter out oet This is the sae assage that counicates the eter-in sring chaber to the eter-out iston. A restriction in the control ca gasket is located in this assage between the relief valve oet and the eter-in sring chaber (between the relief valve oet and reducing valve on electrohydraulic odels). Flow fro the relief valve through the restriction causes ressure to build on the relief valve side of the restriction and is transitted directly to the eter-out iston, which in turn oens the Actuator ort A Tank assage Actuator ort B eter-out servo and eter-out oet, relieving ressure in the actuator ort. The relief valve setting is adjustable by shiing the ilot oet sring, or by using an otional adjustable relief valve. Relief valve override characteristics are given in Figures 29 and 3 on the following four ages. Adjustable relief valves are factory reset at 21 bar (3 si). The adjustent range is fro 1 to 29 bar (145 to 42 si). Adjustent sensitivity is 45 bar (65 si) er turn of the adjusting screw. Adjustable relief (otional) Sring Shis Restriction in control ca gasket Gasket Meter-in sring chaber Meter-in sool Actuator ort relief valve Actuator ort relief valve B A C1 C2 PS DR T LS P PS DR

39 Oerating Valve Section CMX1 Sectional Valve Relief Valve Override S3 Meter-out Poet 4 g b a r k s i CMX1 Sectional Valve Relief Valve Override S14 Meter-out Poet 4 Miniu Setting Flow, l g b a r k s i Miniu Setting Flow, l

40 Oerating Valve Section CMX1 Sectional Valve Relief Valve Override S9 Meter-out Poet 4 g b a r k s i 1 Miniu Setting Flow, l Figure 29c

41 Oerating Valve Section CMX16 Sectional Valve Relief Valve Override S4 Meter-out Poet g b a r k s i Miniu Setting Flow, l CMX16 Sectional Valve Relief Valve Override S7 Meter-out Poet g b a r k s i Flow, l Miniu Setting 25 3

42 Oerating Valve Section CMX16 Sectional Valve Relief Valve Override S14 Meter-out Poet 4 g b a r k s i Flow, l CMX16 Sectional Valve Relief Valve Override S56 Meter-out Poet g b a r k 3 s i Flow, l

43 Oerating Valve Section Hydraulic actuation Pilot ressure is sulied to each section via two #6 SAE O-ring boss orts located on each control ca. Pilot drain connections ust be ade external to the reservoir. External drain is always the referred configuration and MUST be used if tank ressure is high due to the installation or a back ressure check valve, or if high ressure transients ( sikes ) are likely. It is iortant to note that the eter-out servo is referenced to the valve bank drain, while the eter-in sool is referenced to the oosite ort coand ressure. This requires the HRC drain ressures to be considered, since different drain ressures for the valve bank and the HRC will alter eter-in and eter-out hasing. Ideally, both the HRC and the CMX valve bank should be drained directly to the reservoir via generously sized lines. CMX16 Valve (Hydraulic Actuation) Tyical Meter-in Hysteresis Hydraulic actuation data is given below. Tolerance: 1 bar si Test Conditions: S6 Meter-in Eleent 2 bar (29 si) LS 15 Pressure Differential 4 21 cst (1 SUS) Fluid Pilot Requireents: Pressure: 34 bar (5 si) ax. Flow: 12 l (3 USg) reco. Filtration: 25 icrons or finer Required shift volue (dislaceent): l g Coand ressure, bar

44 Oerating Valve Section CMX16 Valve (Hydraulic Actuation) Tyical Meter-out Hysteresis Coand Pressure vs. M-O Flow 2 15 si Test Conditions: S14 Meter-out Poet 4 bar (58 si) Load Pressure 21 cst (1 SUS) Fluid 5 4 l g Coand Pressure, bar Electrohydraulic actuation Electrohydraulic CMX sectional valves oerate on the sae rinciles as the hydraulic valves, with the addition of an electrohydraulic roortional reducing valve (Figure 32) to convert an electrical inut signal to a roortional coand ressure signal that oerates the valve. The solenoid rovides an outut force roortional to the inut current that acts on the solenoid end of the ilot sool. When the solenoid is energized, the ilot sool is oved away fro the solenoid, closing the coand ort to tank and oening the ilot suly to the coand ort. Coand ort ressure is sulied to the feedback end of the ilot sool through the assage in the end ca gasket. When the feedback ressure begins to balance the solenoid force, the ilot sool closes the ilot suly assage. As the coand ressure rises (due to leakage), the feedback ressure overcoes the solenoid, and the ilot sool oves to oen the control ort to tank. The ilot sool odulates to balance the feedback ressure against the solenoid outut force, thus roviding an outut ressure roortional to the solenoid inut current. The ilot sool and bore are designed for zero overla, so deadband is iniized. The ressure outut serves as the coand ressure to actuate the CMX eter-in and eter-out eleents. The signal to the solenoid should be conditioned to a ulse width odulated voltage or current signal. DC ower, u to the coil rating, ay also be used for on-off oeration. Suly Voltages: 12/24 VDC Maxiu Current: 1.4/.7 AMP Recoended PWM Freq. : 1 Hz Solenoids are available with DIN standard 4365 lugs, Metri-Pack connector, or flying leads. Valves are available with either internal or external ilot suly. On odels with the internal ilot otion, ilot ressure is sulied to the roortional reducing valve by an internal assage that is connected to the syste suly assage in the inlet body. These odels require that the iniu syste ressure be aintained to the secified liits to assure roer valve actuation. Electrohydraulic CMX valves ay be oerated anually in the event of electrical control failure by deressing the anual override in, located on the end of each solenoid, with a screwdriver or siilar tool.

45 Oerating Valve Section Pilot suly assage Drain Coil Pole face Pilot suly gallery Manual override Arature Pilot sool Push in Coand ressure assage B A T DR PS LS P PS DR Electrohydraulic roortional reducing valve

46 Oerating Valve Section Electrohydraulic actuation Internal ilot suly Miniu syste ressure: Valves with Tye 6 eter-in sring 19 bar (275 si) Valves with Tye 12 eter-in sring 24 bar (35 si) External ilot suly Miniu ressure: Valves with Tye 6 eter-in sring 19 bar (275 si) Valves with Tye 12 eter-in sring 24 bar (35 si) Since both electrohydraulic reducing valves are referenced to a coon drain via the end cover, drain ressure is not critical. Either an internal drain to tank or an external drain (referred) is available. (Click here to see odel code.). If high ressure transients are resent in the tank line, an external drain should be used to avoid function interaction. If the tank ressure is above 8.6 bar (125 si), an external drain should be used to avoid exceeding the ressure rating for the ilot assages (35 bar [5 si]). Under certain oerating conditions (high inlet ressure, fully shifted, and oen relief valve), ilot drain flow can be as high as 4 l (1 USg) for each active section. Total anticiated drain flow ust be considered when sizing drain lines. Electrohydraulic Reducing Valve for CMX Control Pressure Outut Pressure vs. Coand Current b a r Coand Current, A (12V solenoid) Test Conditions: 4 26 Vickers EMVP-**-1 24 Controller 2.5 V Dither bar (5 si) External 3 2 Pilot Pressure cst (1 SUS) Fluid Coand Current, A (24V solenoid) s i

47 Oerating Valve Section CMX1 Relief Valve Resonse Actuator Port Pressure vs. Tie 3 This lot deonstrates the actuator ort ressure resonse which can be exected when a load is abrutly alied to an actuator, such as an excavator bucket hitting a rock while the boo is being lowered. The resonse is syste-deendent, so actual erforance ay vary. 5 4 Relief Valve Setting: 22 bar (319 si) b a r 2 1 L/in Test Circuit 3 k s i 2 1 C1 A B CMX1 P T C2 1 Rise Rate = 65 Bar/Sec (93, si/second) Elased Tie, Sec.

48 Oerating Valve Section CMX1 Relief Valve Resonse Actuator Port Pressure vs. Tie 5 3 This lot deonstrates the actuator ort ressure resonse which can be exected when a oving load is abrutly stoed by switching the solenoid off. The resonse is syste-deendent, so actual erforance ay vary. 4 Relief Valve Setting: 22 bar (319 si) b a r 2 1 L/in Test Circuit 3 k s i 2 1 PP A B C1 CMX1 C2 P T 1 Rise Rate = 6 Bar/Sec (85, si/second) Elased Tie, Sec.

49 Oerating Valve Section CMX1 Relief Valve Resonse Actuator Port Pressure vs. Tie 3 This lot deonstrates the actuator ort ressure resonse which can be exected when a oving load is abrutly stoed by raidly centering the HRC lever. The resonse is syste-deendent, so actual erforance ay vary. 5 4 b a r 2 Relief Valve Setting: 2 bar (29 si) 1 L/in Test Circuit 3 2 k s i 1 PP A B C1 CMX1 C2 P T 1 Rise Rate = 45 Bar/Sec (64, si/second) Elased Tie, Sec.

50 Secial Features Meter-in ressure liitation In this version (Figure 35), the orifice restriction in the control ca gasket is relocated to the inlet to the eter-in sring chaber. This feature liits eter-in flow at a reset actuator ort ressure.

51 Secial Features Meter-in ressure liitation Meter-out oet version (with ort relief valves) In valves with eter-out oets, the ort relief functions in the noral anner. But because the orifice has been relocated, the relief valve ilot stage also alies ilot ressure to the eter-in sool, which tends to oose the coand ressure. For exale, assue we are driving a cla cylinder P to A. When the cylinder fully clas, the A ort relief setting is reached, and the ilot stage oens and builds ilot ressure to oen the eter-out eleent. This ilot ressure also acts on the eter-in sool oosing the coand ressure and tending to close the eter-in sool, which reduces the eter-in flow. Since a ilot ressure of 4.2 bar (62 si) is required to oen the eter-out oet, a significant reduction in flow, equivalent to 4.2 bar (62 si) coand ressure, through the eter-in sool will occur before the eter-out oet oens. Fro the eter-in coand vs. flow diagras on age 9, the reduction in flow is about 5 l (13 USg) for the CMX1, and about 7 l (18 USg) for the CMX16. The total aount of closing deends on the coand signal and is liited by the relief valve override. When the eter-out eleent is oened enough to ass the full eter-in flow, further increase in relief valve ilot signal will not occur and, in turn, further shutoff of the eter-in is not ossible. In Figure 36 the diagra shows the resulting inlet flow as the load ressure changes while the coand current is fixed. The eter-in ressure liitation feature liits horseower losses through the oen relief valves of a function with relief settings below the syste ressure setting. It is articularly effective for swing functions where the relief valves are set to liit axiu torque. On these alications, with a oving load, eter-in ressure liitation can revent any losses over an oen ort relief valve. The eter-in ressure liitation feature should be used with caution on functions where an overrunning gravity load is ossible. With certain cobinations of eter-out oets and cylinder area ratios, uncoanded oveent ay occur. The use of the eter-in ressure liitation feature ust be aroved by Vickers Systes Engineering Deartent CMX1 Meter-in Pressure Liitation Actuator Port Pressure vs. Inlet Flow S14 M-O Poet, Blocked Actuator Ports si Coand Current 7 A A 4 56 A l 1 49 A 3 g 42 A A Actuator Port Pressure, bar Actuator Port Relief = 172 bar (249 si) Figure 36

52 Secial Features Meter-in ressure liitation Meter-out sool version (no actuator ort relief) In valves with the eter-out sool otion (Figure 37), a relief valve ilot stage is added (no relief ilot stage is resent in the standard configuration), and the orifice is located in the inlet to the eter-in sring chaber. When the ilot stage oens, the resulting ilot signal is alied to both the eter-in and the eter-out sools, oosing the coand ilot ressure and tending to close both sools. Due to the hasing of the eter-in and eter-out sools (the eter-in requires a higher ilot ressure to crack), the eter-in sool will coletely shutoff flow before the eter-out sool will ort fluid to tank. Thus, virtually no horseower is lost when the function is stalled. This feature controls the axiu ressure to a function at a setting below the syste ressure setting. For a rofile of actuator ort ressure versus coand ressure, see Figure 38. Orifice

53 Secial Features CMX1 Meter-in Pressure Liitation Model SP6-M9 (M-O Sool Version) Actuator Port Pressure vs. Coand Pressure b a r si NOTE: The ressure setting is defined as the actuator ort ressure with 14 bar (23 si) coand ressure alied to the oosite coand ort. Test Conditions: Inlet: P LS Pressure Differential = 14 bar (23 si) Blocked Actuator Ports 9 bar ressure setting 21 cst (1 SUS) Fluid Coand Pressure, bar s i Swing drive with free coast This function utilizes a eter-out sool and a ressure controlling eter-in eleent. Cobining these features rovides acceleration control with inial braking. Tyical alications include swing drives and roel functions where braking control is not required or is accolished by a echanical brake. High flow single acting CMX This otion extends the flow range for the CMX valve on alications requiring only a three-way valve (Figure 39, following age). The eter-in sool is sring biased to one end of its bore, and as it is iloted oen, it orts fluid first to the A ort then to both cylinder orts siultaneously. The eter-out oets reain closed when lifting. For lowering, the eter-in sool reains closed. For suerior etering while lowering, different gain eter-out oets can be selected. Both actuator orts ust be connected together externally by the user or by an otional bolt-on block. The otional bolt-on block is available only on the flange ort sections. An otion is available which uses only one eter-out oet when a large eter-out flow area is not required. The dual oet eter-out version is not available for the electrohydraulic narrow body S2 sections.

54 Secial Features High Flow, Single Acting CMX

55 Secial Features CMX Single Acting Meter-in Flow vs. Coand at 2 bar P-LS Pressure Differential si CMX1 H6 CMX16 H6 1 8 l g Coand Pressure, bar (12V coil) Coand (24V coil) Current, A Figure 4a

56 Secial Features CMX1 Single Acting Meter-in Eleent Pressure Coensation Model H6 Meter-in Eleent si l bar (145 si) 8 bar (116 si) Pressure Dro (P-LS), bar Coand Pressure 16 bar (232 si) 14 bar (23 si) 12 bar (174 si) g CMX16 Single Acting Meter-in Eleent Pressure Coensation Model H6 Meter-in Eleent si Coand Pressure l bar (319 si) 2 bar (29 si) 18 bar (261 si) 16 bar (232 si) 14 bar (23 si) 12 bar (174 si) 1 bar (145 si) g 8 bar (116 si) Pressure Dro (P-LS), bar

57 Secial Features Swing drive with ressure controlled braking This feature rovides eter-in ressure control, roortional ressure controlled braking through the coand ressure syste, and blocked actuator orts in neutral. To achieve roortional braking, the eter-out eleent is oerated only by a secial relief valve ilot circuit (Figure 41). (High gain eter out is recoended because of relief valve override characteristics.) The relief valve setting is controlled by the coand ressure, which is accolished by a iston that is acted uon by coand ressure to oose the sring load on the relief valve ilot oet. As the coand ressure increases, the actuator ort ressure required to oen the relief valve oet decreases, effectively decreasing the relief valve setting. Thus when driving a load, the relief valve setting is at a iniu, tyically about 8 bar (116 si). To brake the load, the ilot ressure is decreased, which increases the relief valve setting. The ilot ressure is decreased until the desired braking ressure is achieved. Note: The adjustable relief valve otion is not available with swing drive valve sections.

58 Secial Features Perforance characteristics of the eter out ressure control valve can be lotted using Q-P diagras. Figure 42a is the Q P diagra for the CMX1 S46 eter in sool. Figure 42b is the Q-P (relief valve override) diagra of the P3 relief valve for various coand ressures and a relief valve setting of 28 bar. Cobining these diagras yields Figure 42c (See Figure 42e for CMX16 version). Note that the back ressure fro the oosite actuator ort relief valve has been subtracted fro the constant-ilot-ressure lines, so the ressure scale is the ressure dro across the valve s actuator orts. Now, for a given flow and coand ressure, the ressure available to drive or brake the load can be extracted. If an assued steady state load curve is added (Figure 42d), the chart can be used to deterine the required coand ressure to drive the load at a given seed; or, the equivalent braking ressure (braking ressure lus the load curve) can be obtained. To illustrate the oeration of the valve, assue the load is at rest and the valve is in neutral. Figure 42d shows a braking ressure of 185 bar at oint A, which is the relief valve setting, and the ressure that ust be iosed by an external load to ove the load. As ilot ressure is alied, ressure begins to be alied to the actuator at oint B. When the load ressure is overcoe at oint C, the load begins to ove. If the ilot ressure is increased to 2 bar, the load will accelerate along the 2 bar ilot ressure line until the outut ressure equals the steady-state load ressure at oint E. Note that the ressure available to accelerate the load is the outut ressure at any given flow and ilot ressure inus the steady state load ressure. To slow or sto the load, the coand ressure is reduced. If the coand ressure is reduced to 16 bar (oint F), the load will continue to be driven but at a ressure below the steady-state load curve. The load will slow along the 16 bar line until the steady state load curve is intersected at G oint. If the coand ressure is further reduced to 8 bar, the load will brake until the load stos. Here, the effective deceleration ressure at any given seed is the braking ressure lus the steady-state load ressure. By odulating the coand signal, the oerator has colete roortional control of swing driving and braking ressures. This control rovides sooth, recise control of high inertia swing drives. CMX1 Meter-in Pressure Control Sool Pressure vs. Flow Model S46 Meter-in Eleent 35 g Coand Pressure bar (MAX) 32 bar (464 si) 4 b a r bar (46 si) 3 2 k s i bar (116 si) 12 bar (174 si) 16 bar (232 si) bar (348 si) 2 bar (29 si) 1

59 Secial Features CMX1 Meter-out Pressure Control Relief Valve Override Model P3 Meter-out Eleent g MIN bar (232 si) bar (174 si) 1 b a r bar (116 si) 2 k s i Negative ressure indicates braking ressure 4 bar (58 si) bar ( si) Coand Pressure

60 Secial Features CMX1 Pressure Control Valve Pressure vs. Flow Model S46-P3 g Coand Pressure bar (46 si) bar (348 si) 1 5 b a r 2 bar (29 si) 16 bar (232 si) k s i 5 12 bar (174 si) Flow, l 8 bar (116 si) 4 bar (58 si) bar ( si) 2 3

61 Secial Features CMX1 Pressure Control Valve Pressure vs. Flow Model S46-P3 25 g D Load Pressure Coand Pressure 28 bar (46 si) 3 2 b a r 1 5 C B G E F 24 bar (348 si) 2 bar (29 si) 16 bar (232 si) 1 k s i H 12 bar (174 si) 8 bar (116 si) A 4 bar (58 si) Flow, l bar ( si)

62 Secial Features CMX16 Pressure Control Valve Pressure vs. Flow Model S56-P4 b a r g Coand Pressure 3 28 bar (46 si) 2 24 bar (348 si) 1 2 bar (29 si) 16 bar (232 si) 1 12 bar (174 si) 8 bar (116 si) 2 4 bar (58 si) 3 bar ( si) Flow, l k s i

63 Secial Features Free coast (tye F eter-out) This otion rovides a free coast or float oeration in neutral. This is accolished by a assage between the eter-out sring chaber and the corresonding eter-in chaber (Figure 43). In neutral, ressure in the eter-in chaber is low; thus, the eter-out sring chaber ressure is low, and the eter-out oet will oen when the relatively light sring force of the eter-out servo ste is overcoe. During coanded oeration, a check valve revents flow fro the eter-in chaber to the eter-out sring chaber. Single F eter-out odels hold the load in one direction but not the other. The A*****F and B*****F odels hold the load in one direction but not the other. Dual F eter-out odels give a free coast or float feature in both directions.

64 Secial Features CMX1 Free Coast Perforance F3 Meter-out Poet Flow vs. Pressure Differential b a r Flow A T Flow A T B (T Blocked) g s i l

65 Inlet Bodies Standard end inlet body The standard inlet body (Figure 46) rovides connections for u, tank and load sense. On electrohydraulic valve banks, a connection is also rovided for ilot suly, which ay be internal or external. For internal ilot suly, an internal assage connects the ilot suly to the ressure ort. For external ilot suly, this connecting assage is blocked by a 1/4-28 UNF set screw (.125 in. hex key) accessible through the u ort, and the XP external connection is ade through a #6 SAE O-ring boss ort ( UNF-2B thread). Click here to see other ort sizes. Scheatic of standard end inlet CMX1 CMX16 Figure 46

66 Inlet Bodies End inlet body with load sensing relief valve (CMX1 only) This inlet body (Figure 47) is designed for use with fixed dislaceent us to rovide a cobined function siilar to a variable dislaceent load sensing u, but at a lower syste cost. In addition to the syste connections for ressure, tank, otional load sense and otional external electrohydraulic ilot suly, the inlet section incororates a load sensing relief valve that aintains inlet ressure at a fixed level above load sense ressure and liits axiu inlet ressure to a reset value. The load sensing relief valve uses a balanced sool concet to control inlet ressure. Load sense ressure fro the valve bank is aditted to the sring chaber via a 1.27 (.5 ) orifice. Load sense ressure lus the sring load is balanced against the inlet ressure on the oosite end of the sool. When the load sense ressure lus sring force is overcoe by the inlet ressure, the sool oens allowing inlet flow to tank, thus controlling inlet ressure. When the re-set axiu ressure is reached in the sring chaber, the ilot oet oens, liiting the sring chaber ressure (and then the inlet ressure) since the LS flow into the sring chaber is controlled by the.5 orifice. Note that the re-set axiu ressure ust be atched to the sring(s) used, so the sools are not interchangeable. Two srings are available, which ay be used searately or as a nested air to give three inlet-to-load sense ressure differential settings: 1 bar (145 si), 16 bar (232 si) and 26 bar (377 si). The load sensing relief valve is rated at 25 bar ressure (3625 si). An otional solenoid oerated unloading valve is also available which rovides a direct ath to tank when u standby ressure is not desired. The unloading valve rovides a 4.7 bar (68 si) ressure differential at 1 l (26 USg) and is oen P to T when the solenoid is de-energized. The unloading valve is ressure rated at 25 bar (3 si). An otional external load sense connection is available for secial alications. Load sense connections fro other valve banks should be ade at the end cover when a load sense decoression orifice is used to decoress the load sense assage. The load sense decoression orifice should be located as far as ossible fro the load sensing relief valve. Click here to see orifice location diagra. Orifice Sring chaber Load sense Tank Sool Otional unloading valve Pilot oet Inlet T P T C1 C2 LS P CMX sections Figure 47

67 Inlet Bodies CMX16/1 id-inlet The id-inlet (Figures 48 and 49) facilitates the use of CMX16 and CMX1 valve sections in the sae valve bank. The CMX16 sections are ounted on one side of the id-inlet, and the CMX1 sections are ounted on the oosite side. Syste ressure and tank connections are ade in the iddle of the valve bank, rather than on the end. Standard id-inlet The standard id-inlet (Figure 48) rovides connections for u, tank and external ilot suly (for electrohydraulic valves). Internal ilot suly is available by oitting a set screw lug in a connecting assage between the u ort and ilot suly assage, and lugging the external ort. Load sense and external drain connections for id-inlet valve banks are ade at the end covers. Mid-inlet body CMX 16 s CMX 1 s Internal ilot suly (Plugged for external ilot suly) LS P XP T Figure 48

68 Inlet Bodies Mid-inlet and CMX1-PC** end inlet with reducing valve and anticavitation ake-u flow This id-inlet (Figure 49) incororates two reducing/relieving cartridges to rovide ilot suly ressure and tank ort ake-u flow. The reduced ilot suly ressure can be sulied internally to electrohydraulic sections Make-u flow is an anti-cavitation feature. It is required in circuits where an overrunning load is causing an actuator to ove and draw ore fluid fro the tank ort than is being returned by the oosite actuator ort, and a check valve in the tank line revents fluid fro being drawn fro tank. (A swing function owered by a hydraulic otor is a tyical circuit that requires ake-u flow.) The reducing valve should be set.69 bar (1 si) below the back ressure check valve setting. Drain Pilot suly ort (HRC) PRV2-1 cartridge (ilot flow) Aux. drain ort Tank ort Drain PRV2-1 cartridge (ake-u flow) DR LS CMX 1 s P1 Internal ilot suly (electrohydraulic valve) Inlet ressure T PS P2 CMX 16 s Figure 49