Asphalt Machines
Asphalt Machines Lots of different shapes and sizes
Often Used In Teams
Basic Safety, SW800 & SW850 All brakes on Sakai equipment are referred to as negative brakes. That means they are applied by springs and released by hydraulic pressure. If the engine isn t running or the button is depressed the brakes are applied. Through the use of a solenoid valve, the park brake button either directs charge oil to release the brakes or blocks charge oil to apply the brakes. The brake pedal does the same thing via a micro switch on the pedal linkage. The back up alarm and neutral safety both run off microswitchs at the FNR lever.
Emergency Brake Pedal When not in regular use, coat pedestal lock pin with anti seize
Operational Features In the last slide the brake pedal, steer wheel position locking lever and pedestal lock pin were shown. The brake pedal should not be used except in an emergency. The steer wheel lever secures the wheel at comfortable angle. The pedestal lock pin has 5 positions that lock the operator pedestal into the best angle for operator comfort & best view of the mat. The lock pin will stick if stored a long period without lube and can be difficult to free. Exercise pin often. On the SW800, 850 & 900 all vibe controls can be switched on the go even at full throttle. Amplitude and frequency are changed via solenoid valves from the seat. Primary braking is hydrostatic. There are two water spray systems for redundancy. Do not vibrate while not moving. Shaft bearing lube is dependant on drum rotation.
Drums Drums are machined for smoothness, take care how you treat them! Edges are rounded to reduce marking of the mat, especially when turning. Sakai travel motors are bolted directly to the drum, this keeps rubber isolators healthy. For best weight distribution, travel motors are mounted on opposite sides of the front & rear drums.
Controls are straight forward. The throttle switch below the key switch indicates a Tier 3 engine. Prior to T3 throttle was via lever. Vibe and water controls are on the left. Travel & service braking are via FNR on the right side of seat.
The Diagnostic switch & light is used to alert the operator to problems & identify them via blink codes.
Retrieving Trouble Codes To operate the diagnostic indicator light proceed as follows. Turn on key. The Check Engine light will come on one second then go off. Push the Diagnostic switch up to the on position, the light will come on, then return the switch to the middle position. Be ready to receive blink codes. The code will begin with short blinks, (first number can be as high as 5) longer blinks will follow then another set of short blinks, you are look for a 3 digit code. Operate the toggle switch again for the next code. First code will repeat after last code is reported. If the same code comes out consecutively there is only one code. If Deutz is to be involved in a service call always retrieve codes and get the engine SN off of the valve cover. The SN is required & the codes will be most helpful.
Vibe selector switch determines how vibe control is operated. CONT. means control via FNR thumb button switch, AUTO means vibe will engage anytime FNR is moved away from neutral. If the FNR button stops working try the auto vibe function, if vibe works in AUTO there is a circuit problem with the button control.
Frequency = RPMs, this single switch sets the shaft speed for both drums. The RPM values noted on the dash are dependent on correct engine RPMs.
About the Vibe Pump Unlike the hydrostatic travel pump, the vibe pump is an open center pump. In other words, if the engine is turning the vibe and charge pump are making flow. The vibe pump does use a swash plate but there is no neutral and flow is in one direction only. For this reason, engine RPM is critical. Vibe shaft RPM is a direct result of vibe pump displacement selected via the frequency switch and engine RPM. Even though there are pressure test ports on the vibe pump it is difficult to determine the pump s condition by checking pressure. The best way is to simply check frequency (speed in RPMS) at each drum. This is done with what s referred to as a reed tachometer. It converts vibration into RPM s. These are essential to be properly prepared to diagnose vibratory equipment. They are useful for any task where you want to know RPM. There are actually two vibe pumps of identical displacement with separate circuits housed in one rotating group, that s how both shaft s are kept at the same speed.
Inexpensive Reed Tachometers, websites to order & view instructions are below. When checking VPM with a reed tach use an operator and test on the go when possible. The tach will read off any machine surface, stay clear of the drum. If doing this static, every few minuets you must stop and drive forward a few drum revolutions. This will re-lube the shaft bearings. If the machine isn t rolling the shaft bearings are not being lubricated http://www.treysit.com/6.html http://www.workmaster.net/pdfs/vibra-tak_brochure.pdf
Simple vibe system diagram
The wires seen at the bottom of the frequency control valve connect it to the frequency switch.
Frequency Operation inside the Pump
The frequency solenoid is actually controlling a 3 position swash plate giving the vibe system 3 frequency selections, 2500, 3000 & 4000 RPMs as shown in previous slide. There are 2 amplitude control valves, they are simple single spool open center solenoid controlled valves used to reverse shaft rotation. When turned off they center via springs and vibe pump flow returns to tank and the shaft it controls comes to rest.
Twin Vibration Pumps
Vibe Pump Diagnostics Knowing how the vibe pump, frequency & amplitude control valves work allow you certain logical deductions about the system. If only one drum can change amplitude, check the amplitude control valve driving the problem drum. Then determine if it s the switch, circuit or solenoid. The valve s spool could be stuck but that s rare, it s usually a circuit problem. If there is low speed on one drum the likely cause is a weak motor since a weak pump will affect both motors, not just one. Since both vibe pump sections share the same swash plate both vibe shafts always turn at the same speed. The vibe circuit is arranged to cause vibe shafts to rotate in opposite directions, this neutralizes the horizontal forces generated by the spinning shafts. Always be sure to mark vibe system connections. If there is a performance complaint, measure vibe speed. If it is within 100 VPM of the frequency switch setting there is no problem. Verify engine speed first if shaft speed is low.
Amplitude =Vibration Force Amplitude is determined by the direction of shaft rotation and is measured in distance, each drum can be operated independently in high or low amplitude or be turned off. When turned off, pump flow to the motors is redirected to tank.
Amplitude As stated earlier, amplitude is explained as force to the mat. This force is created by spinning eccentric shafts inside the drums. There are two force settings, high & low. The change from one setting to the other is accomplished by changing the direction of shaft rotation. There is a loud clanging noise associated with starting or stopping the vibration or switching amplitude on the go. Many new users are alarmed by the noise. The noise is caused by the weights slamming into the stops. If the noise is only momentary it is normal. High amplitude is only available at 2500 & 3000 VPM (vibrations per minutes) 4000 VPM at high amplitude will damage the drum. There are safe guards provided to prevent 4000 VPM at high amplitude. They can be overcome accidently, use caution when making hydraulic and electrical repairs to the frequency & amplitude controls. Always use extreme caution when working on the following to prevent this. Vibe motor hydraulic connections, amplitude solenoid control valve hydraulic and electrical connections. Electrical connections to frequency solenoid control valve.
This diagram illustrated what the term Amplitude means. Drum vertical travel is less in low amplitude and about twice as much in high.
In the picture below, you can see how amplitude or force to the mat is changed. There are 2 sets of weights, in each set the outer 2 weights are fixed while the middle weight in each set can move half way around the shaft before contacting the stops. By changing the direction of shaft rotation high or low amplitude is selected.
Vibe shaft in high amplitude, force is at maximum. The small splines to the right connect to the vibe motor. The large splines to the left connect to a second shaft. Late model SW800 s have a solid single shaft.
Vibe Shaft in Low Amplitude Position, Force is Reduced. Vibe shafts must be aligned viewed from the end of the shaft. Later machine vibe shafts have pins in one side that must fit into holes in the second shaft to prevent mis-alignment.
Late model SW800 SN VSW25-50000 and up SW800 with Tier 3 engines use a single piece vibe shaft. There is no coupler and second set of bearings in mid drum as there is in the previous slide showing the SW850 shaft. The shaft does have a set of moveable weights allowing high & low amplitude.
Exact Compact Meter There s not much to diagnose on the Exact Compact Meter. No repairs normally needed inside the box, it s just circuit boards & LED s. Most problems come from the harness, electrical connections and the speed sensor. The speed sensor is threaded into the mount and is adjustable via a lock nut. Clearance between the sensor and the notched wheel on the rear drum should be about the thickness of a dime. Once the machine starts to travel the read out that displays your IPF selection turns into a speedometer. The Exact Compact Meter is standard on SW850 & 900. It is optional on SW800.
Exact Compact Meter On the jobsite, frequency is and speed are watched carefully to give the contractor control of Impacts Per Foot. IPF is exactly that, how many times the drum hits the mat over the course of 1 foot of travel. Typical settings range between 10 to 13 IPF. Fewer strikes and a washboard effect is created, too many and the aggregate in the mix can be damaged by over compaction and time & fuel wasted. Time because at a fixed VPM you can only change IPF by varying travel speed. Faster travel means a lower IPF, slower travel gives a higher IPF. So it s important to establish and then consistently travel at the frequency and speed that obtains the best results in the least time. Contractors find this sweet spot with a test strip then instruct operators accordingly. The exact compact meter makes it easy to consistently deliver best impacts per foot for the mix being used. The exact compact meter is really a speedometer and a calculator with indicator lights. It comes on with the key switch and has a single input button. By pushing the button you can input desired IPF from 8 to 20, after 20, 8 reappears. It receives the frequency setting from the FREQ switch and travel speed from a drum mounted speed sensor. Based on the IPF selected, when underway with vibe on, the indicator lights will guide the operator to the correct speed to obtain the selected IPF
Travel Speed Sensor on Rear Drum
Exact comp meter How it works The exact compact meter has no control over travel or vibration functions. The system examines these factors, position of frequency switch, IPF as input by the operator and travel speed. The meter does calculations based on these factors and simply guides the operator to travel at the correct speed to reach the impacts per foot via the indicator lights.
Travel Hydraulic System Travel system is very basic. The engine is coupled directly to the pump assembly. The pump next to the engine is travel, next is the vibe pump. Some machines have the charge pump at the end of this assembly but most have the charge pump driven directly off an engine gear train PTO. Sudden loss of all Hydraulic functions would mean a coupler failure. Sudden loss of steering would mean charge pump failure. The travel system is a closed loop system, oil is removed from the circuit by the flushing valve located at the rear drive motor & sent to the cooler. The charge pump replaces this oil through internal porting in the travel pump. On an incline the machine will creep in neutral, this is normal. If one drive loses traction & spins, the machine will stop, this is normal because there is a single pump driving two motors. Other than the brief overview above I don t spend much time on the travel function because the system gives very little trouble. In neutral on a slope with engine running, drift is normal.
Tow Valve Sudden loss or reduced travel performance can be caused by an open tow valve. Always check the tow valve first under these conditions.
Engine Diagnosis Working on SW800 and SW850 s you may encounter both Tier 2 & tier 3 engines. Early Tier 2 machines were equipped with Isuzu engines. There are a few Tier 2 Deutz machines. Beginning with SN VSW40-10101 800 s & 850 s are Tier 3 Deutz powered. It s east to recognize a T-3 machine, it will have a 3 position throttle switch instead of the traditional throttle lever. Tier 2 diagnostics remain basic on our machines. We see very few engine issues other than basics like filters, belts, throttle linkage wear and dirty radiators. Tier 3 engines are, as you know considerably more complicated. If you are not properly trained & equipped you should limit the time spent on an engine complaint. Under Sakai s warranty we will pay for reasonable diagnostic time even if the problem is Deutz related. Before calling the Deutz service dealer insure there is ample battery voltage plus fuel & air to the engine. Make other basic checks applicable to the complaint at hand but we advise against going further. Pull trouble codes and get engine SN before calling Deutz.
Water spray system
Water System Water systems on asphalt machines are critical, the machine cannot function without water spraying onto the drums.
The water controls are to the left of the steering wheel. Center switch sets operation mode, CONT will run the pumps selected at all times. A timer mode is used to extend the water supply by preventing waste.
With a single spray bar, to use the auxiliary pump, the pump selector valve must be switched to connect the active pump to the spray bar.
Single spray bar with primary & back up pump.
The difference in the earlier machines spray controls is there is only an option to turn off the primary pump and run the system via the auxiliary pump. Remember since there is no second spray bar the selector valve at the pumps has to be operated so that flow from the Aux pump is sent to the spray bar.
On new machines pump selector toggle switches on the right allow both spray bars on each drum to be active at once. It is unlikely conditions will ever require this. Each pump is connected to a spray bar. Earlier water systems have a primary & secondary pump with only one spray bar. That system requires a valve position change at the pumps to switch between the auxiliary & primary pumps.
Water system schematic decal
Scrapers Scrapers on asphalt machines are plastic. Mounting holes are slotted to allow adjustment for wear. The tab at the end makes it easy to kick them away from the drum. They are held in place via over center springs.
Maintenance Per op manual or maintenance decal on operator station.
Contact Feel free to contact me at any time with questions. Cell 770 712 6168 Email g-petty@sakaiamerica.com