Dual-circuit power brake valve LT 07

Transcription

1 Dual-circuit power brake valve L 7 RE 666 Edition: 7.5 Replaces: 8. Series X Service brake pressure, 6, 8,, and bar Maximum inlet pressure bar For modular designs Features A direct-operated pressure reducing valve in -way design with continuous mechanical actuation Optimum piping possible through freely rotating mounting flange Brake pressure proportional to the actuating force Synchronization thanks to low hysteresis Integrated maximum pressure limitation of the brake circuits All consumer ports on one side Ergonomic adjustment of the pedal work angle possible All pedal models with detachable, slip resistant pedal rubber Compact mounting dimensions Contents Functional description echnical data heoretical curves 5 Ordering code 6 Dimensions 7 Brake pedal models Related documents Fields of application Construction machines Material handling vehicles Forestry and agricultural machinery Specialized vehicles RE 666/7.5, Bosch Rexroth AG

2 L 7 Power brake valve Functional description Functional description he dual-circuit power brake valve L 7 is a direct-operated pressure reducing valve in -way design with continuous mechanical actuation. It has a maximum pressure limitation of the secondary circuits and continuous dosing of the pressure in the secondary circuits (brake circuits) proportional to the path of the actuation element () or to the pedal opening angle (8). In case of failure of one brake circuit, the second brake circuit remains functional by means of mechanical contact of the two control spools (). he actuating force of the pedal remains unchanged. he dual-circuit power brake valve consists essentially of a housing () and control spool (), the main regulator springs (), actuation element () and the return springs (5) and (6). he valve is operated via the actuation element (). his presses both of the main regulator springs () against both control spools (). First, the control edges at channel close, then the control edges of SP to BR open, creating pressure build-up in both brake circuits. he pressure then builds up in the brake lines, acting simultaneously on the brake pressure returns (7) located behind the control spools pushing against the main regulator springs (), so that the brake pressure (secondary pressure) in both brake circuits rises in proportion to the deflection of the actuating element (). In keeping the deflection of the actuation elements constant, the control spools () move into the control position and keep the pressure introduced in the channels BR and BR constant, whereby the pressure in BR is only about bar higher than in BR. he actuation force of the actuation element is proportional to its deflection. If the main regulator springs () are released, the return springs move the control spools back into the starting position. he control edges close from SP to BR and open from BR to. he secondary circuits (braking circuits) are thereby released. Combined mechanical/hydraulic actuation he brake valve can be controlled mechanically by a pedal and/or hydraulically via the Pst port. Version with rotary angle sensor (inching) When the driver presses the brake pedal gently, only the hydrostatic drive brakes via the inch function. he rotary angle sensor converts the pedal angle into an electrical output signal. When the pedal is pressed with more force, this causes the hydrostatics and the service brake to brake simultaneously. hus, the braking process is composed of two parts: an electric and a hydraulic output signal. he control of the pump is connected to the electrical angle sensor of the service brake via the on-board electronics. In the first part of the overall braking action, only the electrical signal is sent, which then lets the drive pump swing back via the electronic system (inching). In the second part, the hydraulic braking pressure is built up (hydraulic braking). Note For versions with rotary angle sensor is cabin fitting for sensor assembly prescribed. Ports SP Supply to service brake circuit SP Supply to service brake circuit ank BR Service brake circuit BR Service brake circuit M Brake pressure return (service brake circuit ) ) M Brake pressure return (service brake circuit ) ) DS Pressure switch (brake lights) Pst Control pressure ) Pressure switch optional (brake lights) Bosch Rexroth AG, RE 666/7.5

3 Power brake valve L 7 Functional description Cross section L 7 MKA Cross section L 7 MKA 8 8 Pst BR BR SP BR 5 SP BR 5 SP M SP M DS 6 DS 6 Symbol L 7 MKA Symbol L 7 MKA BR M BR M Pst BR M BR M DS DS SP SP SP SP Housing Control spool Main regulator springs Actuation element 5 Return spring 6 Return spring 7 Brake pressure return 8 Standard brake pedal RE 666/7.5, Bosch Rexroth AG

4 L 7 Power brake valve echnical data echnical data General Weight Excluding pedal kg.7 With standard pedal kg 6. Installation position Preferably standing Connection type See page Ambient temperature range θ C 5 to +8 Priming One-coat paint RAL 5 Hydraulic Maximum operating brake pressure BR, BR p BR bar at port Maximum intake pressure at port SP, SP p bar Pst p St bar Maximum tank pressure at port p bar.5 (he tank pressure must not exceed the contact pressure of the brake. ank pressure peaks due to flow operations are permitted.) Hydraulic fluid Mineral oil (HL, HLP) according to DIN 55, other hydraulic fluids, e.g. HEES (Synthetic ester) according to VDMA 568 and hydraulic fluids as specified in data sheet 9, on request Hydraulic fluid temperature range θ C to +8 Viscosity range ν mm²/s.8 to 8 Maximum admissible degree of contamination of the hydraulic fluid, Cleanliness level according to ISO 6 (c) Class /8/5, we recommend a filter with a minimum retention rate of β 75 Electric Voltage type DC voltage Supply voltage V to Output signal V.5 to.5 ype of protection according to VDE 7- (DIN EN 659), DIN 5-9 IP67 with installed and locked plug socket Note Please contact us if the unit is to be used outside the specified range of values. Bosch Rexroth AG, RE 666/7.5

5 Power brake valve L 7 heoretical curves 5 heoretical curves Actuation force with and without pedal depending on the braking pressure Brake pressure depending on the control pressure Actuation force F without pedal [N] Version MKA Version MRA 6 8 Brake pressure p BR [bar] Actuation force F with pedal [N] for 5 mm lever arm to rotational axis Brake pressure pbr [bar] Pilot pressure p St [bar] Version MHA Brake pressure and rotary angle sensor voltage signal depending on the pedal angle Output signal [V] Brake pressure pbr [bar] Pedal angle α [ ] Signal Signal Brake pressure Actuation force and brake pressure depending on the actuation path or angle (example: version MKA, bar) Excluding pedal Including pedal Actuation force F [N] Actuation path s [mm] Brake pressure pbr [bar] Actuation force F [N] Pedal angle α [ ] Brake pressure pbr [bar] Force F Brake pressure p BR RE 666/7.5, Bosch Rexroth AG

6 6 L 7 Power brake valve Ordering code Ordering code L 7 X / / M * Series Dual-circuit power brake valve L 7 L 7 ype of actuation Mechanical MKA Mechanical, reduced actuation force MRA Combined mechanical/hydraulic MHA Series to 9 (unchanged installation and connection dimensions) X Preferred type MKA Preferred type MKA Service brake pressure without pedal with standard pedal MKA MRA MHA bar 6 bar R996 R bar R997 R bar R9955 R996 bar R997 R9975 bar Line connections (see page ) 5 Metric thread according to DIN 85- UNF thread according to ISO 96 9 hread according to ISO 69- (with O-ring seal) 5 Sealing material 6 NBR (nitrile rubber) M Pedal (optional) 7 Standard pedal L 9 Electrical rotary angle sensor (optional) 8 Sensor, in the direction of travel left S 9 Connector type D-P (Deutsch) K Output signal Volt F Further specifications in plain text * = Available = Not available Bosch Rexroth AG, RE 666/7.5

7 Dimensions [mm] Power brake valve L 7 Dimensions 7 Dimensions L 7 excluding pedal ø5.8 F ø ca. ca. BR SP M BR M SP DS ø6. + ø59.±. Name plate Actuation stroke Mounting flange 6 rotatable F actuation force M8 ø9 Suggestion for hole pattern in the base plate RE 666/7.5, Bosch Rexroth AG

8 5 8 L 7 Power brake valve Ordering code Dimensions [mm] L 7 with mounted standard pedal L 9 F 7.5 ca BR ca. ca SP M BR 5.5 M SP DS ø Base plate Rubber mat Actuation angle Lever arm F actuation force Suggestion for hole pattern in the base plate Bosch Rexroth AG, RE 666/7.5

9 5 Dimensions [mm] Power brake valve L 7 Ordering code 9 L 7 with mounted standard pedal L 9 and rotary angle sensor S 6 F 7.5 ca BR ca. ca SP M BR 5.5 M SP DS ø Base plate Rubber mat Actuation angle Lever arm F actuation force Suggestion for hole pattern in the base plate RE 666/7.5, Bosch Rexroth AG

10 L 7 Power brake valve Ordering code Dimensions [mm] Line connections Metric thread according to DIN 85-9 Port d Ød Ød t t BR; BR M ød ød +. SP; SP M M d DS M.5.9 M M 8 t t min M M.5 8 Pst M 8 M 8 UNF thread according to ISO 96 9 Port d Ød Ød t t t 5 ød ød +. ± BR; BR 9/ SP; SP 9/ d 9/ DS 7/ t t +. t min M, M 7/ Pst M 8 M 8 hread according to ISO 69-5 Port d Ød Ød t t t 5 ød ød +. 5 ± BR; BR M SP; SP M d M DS M.5..9 t t +. t min M, M M Pst M 8 M 8 Note Ports DS, M and M are usually closed. Bosch Rexroth AG, RE 666/7.5

11 Dimensions [mm] Power brake valve L 7 Brake pedal models Brake pedal models he power brake valve L 7 is supplied with or without pedal. Pedals L 9 and L are available (other models on request). Standard model L 9 / Model L 9 with shortened pedal plate Model L for horizontally-installed brake valve α Note Brake valve and brake pedal are supplied separately. Pedal work angle α adjustable in 5 steps: Hole = 5 Hole = Hole = 5 Hole = (standard model) Note All pedal models come equipped with a slip-resistant, removable rubber mat. he inching function is only possible at a angle. RE 666/7.5, Bosch Rexroth AG

12 L 7 Power brake valve Related documents Related documents he power brake valves L 7 are hydraulic components in the power brake systems of mobile machines. Observe the instructions for the other system components. Only commission the product if the following documentation is available to you and you have understood and observed it. itle Document number Document type Hydraulic power brake valves for mobile applications 66-B Instruction manual Dual-circuit power brake valve L E Spare parts list System documentation from the machine manufacturer Instruction manual Bosch Rexroth AG Mobile Applications Zum Eisengießer 9786 Lohr am Main, Germany Phone info.ma@boschrexroth.de his document, as well as the data, specifications and other information set forth in it, are the exclusive property of Bosch Rexroth AG. It may not be reproduced or given to third parties without its consent. he information provided is solely intended to describe the product. No statements concerning a certain condition or suitability for a certain application can be derived from this information. he information provided does not release the user from conducting their own evaluations and tests. It must be remembered that our products are subject to a natural process of wear and aging. Bosch Rexroth AG, RE 666/7.5