Komatsu WA65-3, WA90-3, WA95-3 Wheel Loader Service Manual

Table of Contents

00 SAFETY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 00-3
01 GENERAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 01-1
10 STRUCTURE AND FUNCTION . . . . . . . . . . . . . . . . . . . . . . 10-1
20 TESTING AND ADJUSTING . . . . . . . . . . . . . . . . . . . . . . . . 20-1
30 DISASSEMBLY AND ASSEMBLY . . . . . . . . . . . . . . . . . . . 30-1
90 APPENDIX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90-1

Manual Extract Variable displacement motor:

Function
• The drive motor is the opposite working principle to the drive pump. In this case oil under pressure is sent to the drive motor.

Oil enters the motor through the control plate into the cylinders. Four or five cylinders are in connection through the kidney shaped inlet port with oil under pressure. The other cylinders are connected through the kidney shaped outlet port to the oil return side.

At least one cylinder is closed at the top or bottom dead center.
The oil pressure forces the piston out, the guide shoes slide on the swash plate and causes the cylinder head to rotate.
The cylinder turns through the action of the nine pistons and so drives the output shaft. The torque required is dependent on the drive pressure and is transmitted to the drive shaft through the pistons in the cylinder head. The oil volume determine the drive speed.

• The drive torque is created directly at the drive shaft from the pistons in the cylinder head.
• A change in the swing angle is achieved by a radial movement of the swash plate with the control piston.
• The swash plate in the variable displacement motor has a small angle in the neutral/ start position. When the 1st drive speed is selected, the variable displacement motor moves to a larger swing angle when taking up the drive and stays in this position.

• When the 2nd drive speed is selected, the swash plate in the variable displacement motor has a small swing angle and stays in this position until a drive pressure of 190 – 200 bar is reached. Above this pressure the swash plate moves to a greater angle and at full drive pressure reaches the largest swing angle.