Patent ID: 8511216
Filing Date: 2013-08-20
Classification: B60Y,F04B,F16H

Abstract:
1. A hydraulic actuator unit comprising a pump case, first and second pump shafts that are supported by the pump case in a rotatable manner around respective axis lines in a state of being positioned in parallel to each other and being operatively connected to each other, first and second hydraulic pump main bodies that are accommodated in the pump case in a state of being supported by the first and second pump shafts respectively in a relatively non-rotatable manner with respect thereto, first and second variable displacement mechanisms that change displacements of the first and second hydraulic pump main bodies, respectively, and first and second electric motors that actuate the first and second variable displacement mechanisms, respectively, the hydraulic actuator unit being characterized in that, the first pump shaft has first and second ends positioned on one and the other sides in its axis line direction, the first end being extended outward from the pump case to form an input end that is operatively connected to a driving power source, the second pump shaft has first and second ends that are positioned on the same side as the first and second ends of the first pump shaft in the axis line direction, the second end being extended outward from the pump case to drive a cooling fan, the first and second variable displacement mechanisms include first and second movable swash plates each of which changes a displacement of the corresponding hydraulic pump main body in accordance with its slanting position around a swing axis line, and first and second control shafts each of which is supported by the pump case in a rotatable manner around its axis line, each of the first and second control shafts has a first end operatively connected to the corresponding movable swash plate in such a manner as to slant the movable swash plate in accordance with its rotation around the axis line and a second end extended outward from the pump case, the first and second control shafts are supported by the pump case in such a manner as that they are orthogonal to the first and second pump shafts and their second ends are faced in the same direction to each other, each of the pair of electric motors has an electric motor main body that is controlled and driven based on an external electric signal, an electric motor output mechanism that is operatively connected to an output shaft of the electric motor main body, and an electric motor case that supports the electric motor main body and the electric motor output mechanism, the hydraulic actuator unit further includes a pair of electric motor covers for connecting the pair of electric motors to the pump case, one of the pair of electric motors is mounted to one of the pair of electric motor covers to form a first electric motor assembly that is detachably mounted to the pump case so as to rotate the first control shaft around the axis line, the other one of the pair of electric motors is mounted to the other one of the pair of electric motor covers to form a second electric motor assembly that is detachably mounted to the pump case so as to rotate the second control shaft around the axis line, the first electric motor assembly is mounted to the pump case so that the corresponding electric motor has a rotational axis line in parallel with the first pump shaft in a state where the electric motor is positioned on an opposite side to the second control shaft with respect to the first control shaft and is also positioned on an opposite side to the first end of the first pump shaft with respect to a virtual plane that passes through the axis lines of the first and second control shafts, and the second electric motor assembly is mounted to the pump case at a posture obtained by rotating the first electric motor assembly by 180 degrees about a virtual center line that is disposed in parallel with the first and second control shafts and is located at a center between the first and second control shafts, thereby the electric motor of the second electric motor assembly is positioned on an opposite side to the cooling fan with respect to the virtual plane.