A hydraulic pump is disclosed which uses a side-discharge valve plate. The present valve plate includes a valve plate body having front and back surfaces with a side defining the peripheral surface therebetween. First and second fluid passages are formed on at least one of said front and back surfaces for respectively defining a fluid inlet for supplying hydraulic fluid to a piston and a fluid outlet for receiving pressurized hydraulic fluid from a piston. At least one fluid access is formed in the side of the valve plate body, connecting with at least one of said fluid passages to define a fluid pathway therewith. The design of the present invention thereby permits a pump design have shorter axial length, permitting a smaller size pump which offers improved space considerations. Also, the present valve plate also has few contact surfaces, thereby reducing leakage and improving pump efficiency.
A piston type compressor having a drive plate (swash plate), wherein sliding friction between the drive plate and shoes is reduced and the compressor is made smaller by slidably attaching the shoes engaged with spherical ends of pistons to a shoe holding plate formed with guide grooves in the radial direction and supporting the shoe holding plate by the drive plate through a thrust bearing. The drive plate is connected to an arm of the shaft side through a double slide link mechanism to enable it to be supported by only a front end of the front housing.
An in-line axial piston hydraulic pump has a cylinder block with a plurality of bores in which separate pistons slide. The cylinder block is supported on one side by a bearing and axle arrangement. The other side of the cylinder block has an integral shaft with a ball that is received in a spherically concave socket coupled to the housing. The socket provides a drive surface that is non-orthogonal to the rotational axis of the cylinder block and the pistons ride against that surface. The engagement of the pistons with that socket surface produces the sliding movement of the pistons within the bores and thus the pumping action.
