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Swing Drive Device and Work Machine

  • US 20080314038A1
  • Filed: 04/10/2006
  • Published: 12/25/2008
  • Est. Priority Date: 06/06/2005
  • Status: Active Grant
First Claim
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1. A swing drive device comprising:

  • a swing motor adapted to receive hydraulic fluid so as to rotate a load for performing swinging operation;

    a swing pump motor that is connected to the swing motor through a closed circuit and adapted to function as a pump for feeding hydraulic fluid to the swing motor and also function as a hydraulic motor driven by hydraulic fluid discharged from the swing motor;

    a directional control valve having a neutral position and a directional control position, the neutral position being a position at which the directional control valve interrupts a passage between the swing pump motor and the swing motor;

    a swing motor generator that is adapted to function as a generator by being driven by the swing pump motor when the swing pump motor is functioning as a hydraulic motor during braking operation of rotation of the load, the swing motor generator also being adapted to function as an electric motor by receiving electric power so as to drive the swing pump motor as a pump;

    an electric power storage device that serves to store electric power fed from the swing motor generator when the swing motor generator is functioning as a generator, electric power storage device also serving to feed electric power to the swing motor generator when the swing motor generator is functioning as an electric motor;

    an exterior-connecting passage for feeding hydraulic fluid from the closed circuit between the swing pump motor and the directional control valve to components outside a swing system;

    a connecting passage solenoid valve that is disposed in the exterior-connecting passage and adapted to be moved between a position for enabling supply of fluid to components outside the swing system and a position for interrupting the flow of fluid; and

    a hydraulic fluid replenishment means that serves to replenish hydraulic fluid in the closed circuit between the swing pump motor and the directional control valve.

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