Hydraulic stepless transmission device

Abstract

A hydraulic stepless transmission having increased layout freedom and a compact structure with the functions of conventional hydraulic stepless transmission retained and having increased easiness of production. In the hydraulic stepless transmission (1), the movable swash plate (input side swash plate (6)) of a variable displacement plunger hydraulic pump or motor is tilted by a hydraulic servo mechanism (3). The hydraulic servo mechanism (3) has a power piston (15) connected to one end of the input side swash plate (6) and tilting it, a servo spool (13) placed normal to the direction of sliding of the power piston (15) and substantially in parallel to the input side swash plate (6), and a feedback link (24) for connecting the servo spool (13) and the input side swash plate (6).

Description

technical field [0001] The present invention relates to the technology of a hydraulic continuously variable transmission device that can be widely used in various vehicles such as motor vehicles and agricultural work vehicles. Background technique [0002] In the past, the hydraulic continuously variable transmission (HST) included: first and second rotating shafts, first and second plungers reciprocating in the axial direction, first and second slides reciprocating in the same axial direction The valve, which accommodates the first and second plungers, the first and second slide valves, and the cylinder that rotates integrally with the first rotating shaft, abuts against the first plunger on a swash plate surface whose inclination angle relative to the axis can be changed. The movable swash plate connected to the axis is a fixed swash plate that abuts against the second plunger and rotates integrally with the second rotating shaft on the swash plate surface at a specified i...

AI Technical Summary

Problems solved by technology

[0007] That is, under such circumstances, it is difficult to configure a hydraulic continuously variable transmission device compactly.

[0008] In addition, in the prior art, for a cylinder block suitable for a hydraulic continuously variable transmission device, a cylindrical steel material is machined to form a plurality of holes, and it is produced through a time-consuming process such as boring, which requires a lot of man-hours.

Therefore, it is difficult to make the cylinder

[0009] In addition, since the details of the cylinder must be machined, it is also difficult to miniaturize the cylinder itself, and thus it is also difficult to miniaturize the hydraulic continuously variable transmission as a whole.

[0010] Furthermore, the first and second spool valves mentioned above often repeatedly slide back and forth at a certain timing to switch the oil passage during the operation of the device. If the timing is out of order, the hydraulic continuously variable transmission cannot operate normally. timing must be fixed

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