MSW020/025-E [A895]; MPB040-E [B827]; MPW045-E [B802]; MPW050-E [C802] PART NO YRM

Transcription

1 Maintenance BRAKES MSW020/025-E [A895]; MPB040-E [B827]; MPW045-E [B802]; MPW050-E [C802] PART NO YRM 1005

2 SAFETY PRECAUTIONS MAINTENANCE AND REPAIR When lifting parts or assemblies, make sure all slings, chains, or cables are correctly fastened, and that the load being lifted is balanced. Make sure the crane, cables, and chains have the capacity to support the weight of the load. Do not lift heavy parts by hand, use a lifting mechanism. Wear safety glasses. DISCONNECT THE BATTERY CONNECTOR before doing any maintenance or repair on electric lift trucks. Disconnect the battery ground cable on internal combustion lift trucks. Always use correct blocks to prevent the unit from rolling or falling. See HOW TO PUT THE LIFT TRUCK ON BLOCKS in the Operating Manual or the Periodic Maintenance section. Keep the unit clean and the working area clean and orderly. Use the correct tools for the job. Keep the tools clean and in good condition. Always use YALE APPROVED parts when making repairs. Replacement parts must meet or exceed the specifications of the original equipment manufacturer. Make sure all nuts, bolts, snap rings, and other fastening devices are removed before using forcetoremoveparts. Always fasten a DO NOT OPERATE tag to the controls of the unit when making repairs, or if the unit needs repairs. Be sure to follow the and CAUTION notes in the instructions. Gasoline, Liquid Petroleum Gas (LPG), Compressed Natural Gas (CNG), and Diesel fuel are flammable. Be sure to follow the necessary safety precautions when handling these fuels and when working on these fuel systems. Batteries generate flammable gas when they are being charged. Keep fire and sparks away from the area. Make sure the area is well ventilated. NOTE: The following symbols and words indicate safety information in this manual: Indicates a condition that can cause immediate death or injury! CAUTION Indicates a condition that can cause property damage!

3 Brakes Table of Contents TABLE OF CONTENTS General... 1 Description... 1 Special Precautions... 2 Brake Assembly Repair... 3 Brake Override... 3 Remove... 4 Repair... 6 Install... 7 Troubleshooting... 8 This section is for the following models: MSW020/025-E [A895]; MPB040-E [B827]; MPW045-E [B802]; MPW050-E [C802] 2005 Yale Materials Handling Corp. i

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5 1800 YRM 1005 Description General Do not operate a lift truck that needs repairs. If a repair is necessary, put a DO NOT OPERATE tag on the control handle. Remove the key from the key switch. Before performing repairs or adjustments on the brake system, blocks must be placed under each side of the frame to raise the drive tire off the ground. The blocks must prevent the lift truck from falling and causing personal injury or property damage. See Periodic Maintenance 8000 YRM 1009 or Periodic Maintenance 8000 YRM 1048, How to Put a Lift Truck on Blocks. Always disconnect and separate the battery connector so that the connector is completely free before performing any service or repairs. If the connector is not completely free, it can reconnect. Tag the connector: DO NOT CONNECT. This section has the description and repair procedures for the electric brake on the MSW020-E, MSW025-E, MPB040-E, MPW045-E, and MPW050-E lift trucks. Brake assemblies may vary in appearance. Although some assemblies may APPEAR to be adjustable, brake assemblies used on these trucks ARE NOT ADJUSTABLE. Friction between parts inside the brake will produce brake dust, squeaking, and extreme heat under normal operating conditions. Brake assemblies can generate surface temperatures up to 130 C (266 F) and odors during heavy operation. Functions of the brake assembly depend on a dry and clean environment. Small amounts of oil or grease on the friction surfaces of the brake can seriously compromise the brakes ability to function. Description Motorizedhandtruckshavethreemethodsofbraking: 1. Regenerative (Neutral) braking 2. Controlled plugging 3. Application of the spring-applied/electrically released friction brake NOTE: The preferred method of stopping the truck is: Regenerative (Neutral) braking or Controlled plugging Regenerative (Neutral) braking applies a retarding force to the drive wheel through the traction motor, allowing the unit to slow to a gradual stop. It is applied by returning the speed/direction control to the OFF position or by placing the hand brake lever(s) in the first stage position. Controlled plugging is reversing the speed/direction control while traveling, causing the unit to slow to a stop. Return the speed/direction control to the OFF position to remain stopped. If the speed/direction control is not returned to the OFF position, the lift truck will accelerate in the opposite direction. Controlled plugging should stop the truck within a few feet, depending on speed and load. The parking brake is a spring-applied, electrically released friction brake mounted to the drive motor. When the parking brake is applied, springs inside the brake assembly compress a rotating friction disk against two stationary plates. To release the brake: 1. Connect the battery. 2. Turn the key switch to the ON position. 3. Lower the control handle arm to the operating or BRAKE OFF position. Refer to Figure Rotate direction/speed control (butterfly knobs) in the direction of travel. 1

6 Special Precautions 1800 YRM 1005 The parking brake is applied when the control handle arm is moved to the BRAKE ON position (full up or full down position) or if a traction fault occurs. The lift truck must meet the applicable HOLD ON GRADE requirements; the parking brake should be capable of holding the lift truck on a 10 percent grade with the maximum rated load. Figure 1. Brake Operation Block each side of the truck under the drive unit frame. Position blocks on both sides of the load wheels. The blocks must prevent the lift truck from falling and causing personal injury or property damage. The capacitor in the transistor controller can hold an electrical charge after the battery is disconnected. To prevent electrical shock and personal injury, discharge the capacitor before inspecting or repairing any component. Wear safety glasses. Make certain the battery has been disconnected. Discharge the capacitors in the controller by connecting a 200-ohm, 2-watt resistor across the controller s B+ and B terminals with insulated jumper wires. Do NOT use a screwdriver to discharge the traction motor controller. See Figure 2 or Figure 3. To avoid personal injury and prevent electrical shock, perform the following steps before performing any troubleshooting or adjustments, and Special Precautions before connecting or disconnecting a handset or computer. CAUTION To avoid controller damage, always disconnect the battery. Discharge the capacitor and never put power to the controller with any power wire disconnected. Never short any controller terminal or motor terminal to battery. Make sure to use proper procedure when servicing the controller. 1. Block the lift truck so that the drive wheel is off the floor. Refer to the proper section for your truck: Periodic Maintenance 8000 YRM 1009 or Periodic Maintenance 8000 YRM 1048, How to Put a Lift Truck on Blocks. 2. Turn the key switch to the OFF position and disconnect the battery. 3. Discharge the capacitors in the controllers by connecting a 200-ohm, 2-watt resistor across the controller s B+ and B terminals. See Figure 2 or Figure 3 for your truck. DO NOT short across the motor controller terminals with a screwdriver or jumper wire. Remove the 200-ohm, 2-watt resistor before reconnecting the battery. 2

7 1800 YRM 1005 Brake Assembly Repair 1. POSITIVE CONNECTION 2. NEGATIVE CONNECTION 3. INSULATED JUMPER WIRES OHM, 2-WATT RESISTOR Figure 2. Discharging Controller MPB040-E 1. NEGATIVE CONNECTION 2. POSITIVE CONNECTION OHM, 2-WATT RESISTOR 4. INSULATED JUMPER WIRES Figure 3. Discharging Controller MSW020/025-E and MPW045/050-E Brake Assembly Repair BRAKE OVERRIDE CAUTION Never operate the lift truck while the brake override feature is being used. The brake can be disengaged when a truck cannot be operated but needs to be moved. On the main wiring harness approximately 300 mm (12 in.) above the MDU, the brake wiring harness is connected. An extra four pin connector for the brake override feature is secured near this connection with wire ties. Disconnect the connectors and connect the brake wiring harness to the brake override connector. This will energize the brake coil which will release the brake. The drive motor will not activate while the jumper is installed. Roll the lift truck to a safe location and disconnect the brake override connector. The brake will apply when the brake override connector is disconnected or when power to the brake override circuit is interrupted. Reconnect the brake wiring harness to the main wiring harness and proceed with repairs. If the battery does not have sufficient charge, or if certain components of the lift truck are damaged, the brake may not release with the brake override circuit engaged. In this case, the malfunction must be corrected before the brake can be released. See Figure 4. 3

8 Brake Assembly Repair 1800 YRM 1005 or repairing any component in the MDU compartment to prevent personal injury and damage to the electrical system. Always wear safety glasses. 3. Discharge capacitors. Refer to Special Precautions in the front of this section. 4. Remove Allen-head screws (7) and washers (8) from the cover that secure motor and brake assembly to MDU. 5. Support drive motor with one hand and remove remaining Allen-head screw (2) and washer (3) with other hand. 6. Remove motor and brake assembly from MDU. 7. Tag and remove wires and cables from motor and unplug brake wire harness. 8. Place motor on workbench securely supported in an upright position. 9. Remove O-ring from housing. 1. BRAKE WIRING HARNESS 2. MAIN WIRING HARNESS 3. BRAKE OVERRIDE CONNECTOR REMOVE Figure 4. Brake Override Connector Move the truck to a safe location before beginning work and block the wheels to prevent movement. Remove the key from the switch and disconnect the battery connector. NOTE: For the following instructions, refer to Figure Turn key switch to OFF position and disconnect battery. Block the drive tire to prevent movement. 2. Remove drive unit compartment covers and MDU covers. The capacitor in the transistor controller can hold an electrical charge after the battery is disconnected. Discharge the capacitor before inspecting 10. Remove nut (9) from motor shaft. 11. Remove gear (11) and woodruff key (16) from drive motor shaft. 12. Using a standard puller, remove the bearing (13) andoilslinger(12)fromdrivemotorshaft. CAUTION Brake assemblies may vary in appearance. Some assemblies have three Allen-head screws on top of the brake coil. DO NOT REMOVE the Allen-head screws on TOP of the brake coil. This can change the factory preset adjustment, rendering the brake inoperable. These brakes are preset from the factory and are NOT ADJUSTABLE. 13. Using a 3 mm Allen-head insert at least 55 mm long with a square socket adaptor, remove three Allenhead capscrews securing bottom plate of brake assembly to motor. 14. Slide brake from drive motor shaft. 15. Remove spacer (10), hub (18), and woodruff key (17). 4

9 1800 YRM 1005 Brake Assembly Repair 1. MDU HOUSING 2. ALLEN-HEAD SCREW 3. WASHER 4. DRIVE MOTOR 5. COVER 6. FILL PLUG 7. ALLEN-HEAD SCREW 8. WASHER 9. NUT 10. SPACER 11. GEAR 12. OIL SLINGER Figure 5. Brake Assembly 13. BALL BEARING 14. O-RING 15. BRAKE ASSEMBLY 16. WOODRUFF KEY (GEAR) 17. WOODRUFF KEY (HUB) 18. HUB 5

10 Brake Assembly Repair 1800 YRM 1005 REPAIR If a brake assembly is malfunctioning, the cause may be electrical, mechanical, or a combination of both. If the brake electrical system is functioning correctly, the brake should release with one solid "click" when energized. The brake coil is a large 24 V coil that acts as an electromagnet to pull the armature plate away from the friction disk. If the brake coil is too weak to compress the brake springs and release the friction disk, the brake must be replaced. 1. Disconnect the brake wiring harness (if brake is installed to truck). If removing the drive motor assembly from the lift truck, visually inspect the brake and check the air gap to determine if the brake is near the end of normal service life. Use a feeler gauge to check the gap between the brake coil and armature plate. Proper air gap measurements range from 0.2 to 0.6 mm ( to in.). See Figure 6. The brake must be replaced if it no longer meets the proper air gap specifications or if otherwise malfunctioning. The brake hub and the brake assembly can be replaced separately. However, if there is damage to the brake hub, there is most likely damage to the brake assembly. 2. Check voltage to the brake using a voltmeter. a. Turn the key switch to the ON position. b. Place the control handle arm in the BRAKE OFF position. c. Lightly rotate the directional controls to activate the brake coil circuit. d. Touch each lead of a voltmeter to each side of the MAIN WIRING HARNESS connector where the brake wiring harness connects. e. Voltage to the brake should read approximately 24 V. 3. Check the resistance of the brake coil using an ohmmeter. a. Touch each lead of the ohmmeter to each side of the brake wiring harness connector. b. If the brake coil resistance reads between and (ohms), the brake coil is functioning properly. c. If the resistance reading falls outside the specified range, the entire brake assembly must be replaced. If the brake mechanical functions are not operating correctly, the brake will not hold a fully loaded lift truck on a 10% grade. The brake is NOT ADJUSTABLE and must be replaced when it will not hold to specification. 1. BRAKE COIL 2. AIR GAP 3. ARMATURE PLATE 4. FEELER GAUGE Figure 6. Brake Assembly 6

11 1800 YRM 1005 Brake Assembly Repair INSTALL For the following instructions, refer to Figure Install woodruff key (17) to drive motor shaft and slide hub onto shaft and key. Make sure groove and key are aligned properly. 2. Install spacer (10) and brake assembly on to motor shaft and slide down on to hub. Make sure brake spline align with teeth on the hub. CAUTION Brake assemblies may vary in appearance. Some assemblies have three Allen-head screws on top of the brake coil. DO NOT TURN the Allen-head screws on TOP of the brake coil. This can change the factory preset adjustment, rendering the brake inoperable. These brakes are preset from the factory and are NOT ADJUSTABLE. 8. Place motor shaft assembly into housing. Position motor and brake correctly to align brake wiring harness in notch. See Figure 7. Hold the motor in place until next step is complete. 9. Install Allen-head screw (2) and washer (3). 10. Install Allen-head screws (7) and washers (8). Torque all three Allen-head screws to 10 N m (7 lbf ft). 11. Install MDU covers and drive unit compartment covers. 12. Reconnect battery, and remove blocks from wheels. 13. Brake should hold parked lift truck loaded to capacity on a 10% grade. Test for proper operation before returningtoservice. 3. Using a 3 mm Allen-head insert at least 55 mm long with a square socket adaptor, install three Allenhead capscrews securing bottom plate of brake assembly to motor. Torque to 2.8 N m (25 lbf in) 4. Install bearing assembly (13), and oil slinger (12), on to shaft using a standard press. 5. Install woodruff key (16), gear (11), and nut (9) to shaft. Torque nut to 26 N m (19 lbf ft). 6. Install O-ring into housing. Lubricate O-ring with grease to ensure proper installation of drive motor shaft assembly. 7. Reconnect wiring as removed. CAUTION The brake wiring harness must be aligned with the notch in the MDU housing. If the motor and brake assembly is secured to the MDU incorrectly, the brake wiring harness may be damaged. 1. MDU HOUSING 2. BRAKEWIRENOTCH Figure 7. MDU Brake Wire Notch 7

12 Troubleshooting 1800 YRM 1005 Troubleshooting PROBLEM POSSIBLE CAUSE PROCEDURE OR ACTION Brake does not release. Key switch is in the OFF position. Turn key switch to the ON position. Handle is not in the BRAKE OFF position. Control handle arm prox switch is out of adjustment/damaged. Coil is open. Coil has shorted to frame or between the windings. Incorrect or no voltage supplied to brake. Air gap is too large. MovethehandletotheBRAKE OFF position. Adjust/replace control handle arm prox switch. See the section Electrical System 2200 YRM Measure coil resistance. If resistance is too high (above ), replace the brake assembly. Measure coil resistance. If resistance is too low (below ), replace the brake assembly. Check coil for short to frame using an ohmmeter. If shorted to frame, replace the brake assembly. Measure voltage to brake using a voltmeter. If voltage is not 24 VDC ±10%, check connector. Troubleshoot electrical system. Replace the brake assembly. Brake does not hold truck loaded to capacity on 10% grade. Air gap is too large. Friction disk is too worn. Brake hub damaged. Replace the brake assembly. Replace the brake assembly. Replace brake and hub assembly. 8

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14 Yale Materials Handling Corp Sullivan Dr., Greenville, NC YRM /05 (5/03 )(1/02) Printed in U.S.A.