| 摘要 |
<p>1,164,868. Hydrostatic transmission control. INTERNATIONAL HARVESTER CO. 23 Oct., 1967, No. 48075/67. Heading F2D. In a reversible hydrostatic transmission comprising a reversible variable-displacement swash-plate pump (11), Fig. 1 (not shown), and a similar motor (13), in which the swashplate angles are adjusted by hydraulic servocylinders 24, 25 through known linkages 26, 27, (not further described) and the servo-cylinders are controlled by cam slots 33-36 in a camplate 31 fast on a shaft 19 carrying a pedal or hand lever 22, which slots 33-35 act to uncover exhaust valves 44, 45 in the servocylinders on rotation of the cam-plate on either side of a centre neutral position, the cam plate, and hence the transmission, is automatically returned to its neutral position on removing pressure from the lever 22 by a spring 52, which spring also provides a substantially constant resistive torque to movement of the lever 22 from any position away from the neutral centre position. Raising or lowering of the lever 22, for reverse or forward, from its neutral position, rotates the cam-plate 31 and one of two levers 46, 46a, freely mounted on the shaft 19, by the abutment of a stud 53, on the cam-plate, with a shoulder 51 or 51a on the respective lever, the other lever being held by a stop 54 engaging one end of a recess 50, 50a in the lever. The levers carry the spring 52 between their ends 49, 49a, so that, on release of the lever 22, the spring urges the rotated lever, and hence the cam-plate back to its neutral position. Also, rotation of one lever extends the spring to increase its tension, but also the line of action of the spring is moved nearer to the shaft reducing its effective lever arm, and maintaining its moment about the shaft 19 substantially constant. Rotation of the cam, and hence slots 33-36 controls the servo-cylinders to first increase the tilt angle of the pump swash-plate from minimum to maximum, and then to reduce the motor swash-plate angle from maximum to minimum. The servo-cylinders are pivoted at their lower ends, and the engagement of cam follower 55, on servo-cylinder 24, in camslot 36 facilitates control of the pump swashplate.</p> |
