| 摘要 |
To enable effective use of the end portion of a male screw formed on a screw shaft in a ball screw mechanism for controlling the rolling of a swash plate. A hydraulic motor (M) comprises a motor cylinder 32 having motor plunger holes 32a, motor plungers 33 laid in the respective plunger holes, and a motor rolling member 35 which is tilted and rolled to change the angle of a swash plate. A motor servo mechanism (SV) for tilting and rolling the motor rolling member 35 (motor swash plate 31) comprises a screw shaft 61 having a male screw 61a, a ball nut 62 which has a ball thread 62a to be mated with the male screw and is connected to the arm portion 35a of the motor rolling member, and a swash plate control motor 67 for driving the screw shaft. A stopper 70 mounted to the end of the screw shaft consists of a ring portion 71 situated adjacent to the end of the male screw and a flange portion 72 to which the side face of the ball nut is contacted.
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