Kanzaki Kokyukoki Mfg. Co., Ltd.

Yanmar Co., Ltd.

Yasuhisa Mochizuki

Koji Sakata

Ryota Ohashi

Toshifumi Yasuda

Kazuhiro Owada

Tomoyuki Tsuji

Hidemi Harada

Masaki Watanabe

Tooru Oota

Hideaki Syokita

An outer circumferential surface of a trunnion shaft includes a sliding contact region that has a circular arc shape as viewed along a slanting axis line and is substantially brought into contact with an inner circumferential surface of the bearing portion in a rotatably sliding manner, and at least one suction groove that forms a pocket portion between the suction groove and the inner surface of the bearing portion. The pocket portion is opened to an inner space of housing on at least one side in an axis line direction of the trunnion shaft.

Variable displacement axial piston device

In a hydrostatic transmission (HST), a lubricating fluid passage is formed in an input shaft and has a pair of radially opposite lubricating fluid spill ports open at an outer peripheral surface of the input shaft. Both of the radially opposite lubricating fluid spill ports face a lubricated object of the HST. The lubricating fluid passage includes an axial fluid passage and a pair of radial fluid passages that are extended radially from the axial fluid passage to the outer peripheral surface of the input shaft so as to be radially opposite each other. Open ends of the respective radial fluid passages at the outer peripheral surface of the input shaft serve as the respective radially opposite lubricating fluid spill ports.

Hydrostatic transmission

A hydrostatic transmission comprises a hydraulic pump, a hydraulic motor, first and second main fluid passages fluidly connecting the hydraulic pump to the hydraulic motor so as to constitute a closed fluid circuit, a charge fluid passage, a plurality of first charge check valves and a plurality of second charge check valves. The plurality of first charge cheek valves are interposed between the charge fluid passage and the first main fluid passage so as to allow only flow of fluid from the charge fluid passage to the first main fluid passage when the first main fluid passage is hydraulically depressed relative to the charge fluid passage. The plurality of second charge check valves are interposed between the charge fluid passage and the second main fluid passage so as to allow only flow of fluid from the charge fluid passage to the second main fluid passage when the second main fluid passage is hydraulically depressed relative to the charge fluid passage.

A hydrostatic transmission includes a closed fluid circuit, a hydraulic motor, a hydraulic pump fluidly connected to the hydraulic motor via the closed fluid circuit, and a fluid charging mechanism which supplies fluid delivered from the hydraulic pump to the closed fluid circuit during driving of the hydraulic pump.

A hydrostatic stepless transmission comprises: a hydraulic pump; a hydraulic motor, wherein at least one of the hydraulic pump and motor is variable in displacement, and is provided with a movable swash plate; a closed circuit connecting the hydraulic pump and motor to each other through a pair of main fluid passages, wherein one main fluid passage is higher-pressurized during forward traveling, and wherein the other main fluid passage is higher-pressurized during backward traveling; a hydraulic servomechanism for controlling a tilt angle of the movable swash plate of the at least one of the hydraulic pump and motor; a speed-controlling motive member attached to the hydraulic servomechanism, wherein the speed-controlling motive member interlocks with the movable swash plate and is moved by operating a speed control operation lever; and a load controlling system attached to the hydraulic servomechanism. The load controlling system includes an actuator for moving the speed-controlling motive member in a direction for deceleration, and a pair of check valves connected to the respective main fluid passages. Fluid is led from either of the main fluid passages to the actuator through the corresponding check valve so as to serve as an element for detecting load and as hydraulic pressure fluid for actuating the actuator.

Hydrostatic stepless transmission

There is provided a multiple pump unit including a pump shaft, a first pump, a pump housing, a second pump and a fluid passage block connected to one end surface in an axis line direction of the pump housing. One or both contacting surfaces of the pump housing and the fluid passage block is formed with a concave portion for accommodating the second pump. The pump housing is provided with a suction fluid passage guiding hydraulic fluid to a suction opening of the first pump and a first pump discharge fluid passage having a distal end that forms a first pump discharge port. The fluid passage block is provided with a second pump discharge port having the second pump as a hydraulic source.

Multiple pump unit

There is provided a hydrostatic transmission (HST) in which a hydraulic pump unit operatively driven by a driving power source and a hydraulic motor unit arranged spaced apart from the hydraulic pump unit and operatively driving a driving-wheel are fluidly connected by way of operation fluid lines so as to form a closed circuit. The hydraulic motor unit is provided with motor-side operation fluid passages forming one part of the operation fluid lines. A motor-side charge fluid passage having a first end opened to an outside to form a motor-side charge port and a second end fluidly connected to at least one of the motor-side operation fluid passages is also included. A check valve is interposed in the motor-side charge fluid passage so as to allow the fluid to flow from the motor-side charge port to one motor-side operation fluid passage while preventing reverse flow.

Growing community of inventors

Amagasaki, Japan

Yasuhisa Mochizuki