JPH0716138Y2 - Shift buffer for HST transmission - Google Patents

Description

[Detailed Description of the Invention] (a) Industrial field of application The present invention relates to a structure of a shock absorber for preventing a sudden change during a gear shift operation of an HST type transmission and for absorbing a shock at the time of gear shift rotation. is there.

(B) Prior Art Conventionally, a structure in which a shock absorber is provided in connection with a gear shift operation portion of an continuously variable transmission has been known. For example, Japanese Utility Model Sho 61-32653, Japanese Utility Model Sho 59-149523, Japanese Utility Model Sho 60-662.
The technology is disclosed in No. 9 and No. 57-5327.

(C) Problems to be solved by the invention These conventional shock absorbers are commercially available ones that are arranged near the operation lever or operation pedal portion, and are also arranged outside the mission case. The material had to be sealed and rust-proofed, which was expensive.

(D) Means for Solving the Problem The present invention has the following configuration in view of such a point.

In an axle drive device in which an HST transmission is arranged in the mission case 10, a transmission arm for rotating a rotating swash plate 25 of the HST transmission and one end of a rod protruding from the damper A are pivotally connected, The damper A is configured as a gas type damper and is disposed outside the lubricating oil in the transmission case 10.

(E) Embodiment of the Invention The purpose and structure of the present invention are as described above, and the structure of the embodiment shown in the accompanying drawings will be described.

FIG. 1 is an internal plan view of an HST type axle drive equipped with the shock absorber of the present invention, and FIG. 2 is a side sectional view of a damper mounting portion.

Power is transmitted from the engine on the traveling vehicle to the pulley on the pump shaft 24 protruding from the transmission case 10 via the V belt, and the rotation of the pump shaft 24 drives the hydraulic pump P to discharge pressure oil. The motor shaft 28 of the hydraulic motor M is driven.

A brake drum 40 is fixedly attached to the tip of the motor shaft 28, and the brake drum 40 is braked by being tightened by a brake pad by depressing a brake pedal. A counter shaft in which a large diameter gear 46 is meshed and the large diameter gear 46 is fixedly installed.
An engraved gear 47 is engraved on the 22. The ring gear 48 of the differential device D is meshed with the engraved gear 47, and the motor shaft is
The rotation of 28 drives the axles 11L and 11R via the engraved gear 45, the large diameter gear 46, the engraved gear 47, and the ring gear 48.

The hydraulic pump P is attached on the horizontal plane of the oil passage plate 23 configured in an "L" shape, and the hydraulic motor M is attached on the outside of the vertical surface of the oil passage plate 23, and is arranged in the upper and lower halves of the oil passage plate 23. The mission case 10 is fixed to the lower surface of the upper half case 10a.

The discharge direction and discharge amount of the pressure oil from the hydraulic pump P are determined by the pump shaft.
It is adjusted by changing the inclination of the rotary swash plate 25 fitted on the outer periphery of the rotary swash plate 24, and the rotary swash plate 25 is rotatably operated by the speed change arm lever 9 through the sliding body 9a.
It is fixedly mounted on a pivot pipe 5 which is pivotally supported by 15, and a transmission arm 7 and an arm 12 are further projected from the pivot pipe 5, and a transmission roller 8 is axially supported at the tip of the transmission arm 7. The shift roller 8 is fitted in the cam groove 1a of the shift cam plate 1.

The speed change cam plate 1 is fixed to a speed change cam plate shaft 13, and is connected to a speed change lever or a speed change pedal through a link 18 from an arm 19 fixed to the speed change cam plate shaft 13 and is rotated by an operator's speed change operation. The swash plate 25 is configured to rotate.

The cam groove 1a formed in the shift cam plate 1 reduces the speed increasing rate near the shift neutral position of the shift roller 8 with respect to the normal rotation of the shift cam plate 1, and increases the speed away from the neutral position. The position is set to increase the speed increase rate.

A biasing spring 6 is pivotally supported on the shift cam plate shaft 13 to which the shift cam plate 1 is fixed, and a pin 33 projecting from the bottom face of the shift cam plate 1 and a pin 33 projecting from the bottom face of the shift cam plate 1 with their ends intersecting each other. When the shift cam plate 1 is rotated with the pinch 20 in between, one of the urging springs 6 is simultaneously rotated, but the other is locked by the pin 20, so a force to return is exerted, and the shift cam plate 1 is rotated. 1
Is configured to return to the neutral position.

In this overall structure, the damper A, which is the main part of the present invention, is fixed to the pivot pipe 5 and is fixed to the arm 12.
It acts as a buffer when shifting gears. That is, the support plates 35 and 36 are fixed to the upper half case 10a in the space between the differential device D and the speed change cam plate 1, the damper case 37 is fixed to the support plates 35 and 36, and the lubricating oil surface B
It is arranged in a position above which lubricating oil is not applied.

The damper A has a sliding body 32 inserted in a damper case 37, and the sliding body 32 projects rods 32b and 32b on both sides of a piston 32a. Piston holes 32c are formed in the piston 32a so that both sides of the damper case 37 can be formed. It is closed with lids 16 and 17. The interior of the damper case 37 may be filled with air or other gas. The rod 32b on the one side is pivotally connected to the arm 12.

With this configuration, when the operator operates the gear shift lever or the gear shift pedal, the arm 12 is also rotated, the rod 32b is slid, and the piston 32a slides in the damper case 37. At this time, the damper case 37
The gas inside passes through the throttle hole 32c and enters the damper chamber on the other side, and the passage of this gas is regulated by the throttle hole 32c, so that a rapid shift operation can be prevented.

Further, FIG. 3 shows an embodiment in which the damper A is integrally formed with the oil passage plate 23, and the air in the damper case 23a communicates with the inside of the mission case 10. The vertical portion of the oil passage plate 23 is shown in FIG. Damper case at a position not soaked in lubricating oil on the top of the
23a is arranged, and a sliding body 32 'is installed in the damper case 23a in the same manner as described above, and both ends of the damper case 23a are covered with a lid body 16'.
.Closed at 17 'and squeeze holes 16 in the lids 16' and 17 ', respectively.
By providing a ′ · 17a ′, air can flow from the throttle holes 16a ′ · 17a ′ into the damper case 23a and the mission case 10, and the air serves as a cushioning material.

Therefore, similarly to the above, at the time of gear shifting operation, the air flows in from one side through the throttle holes 16a 'and 17a' by the sliding of the rod 32b 'and flows out from the other side, and this inflow / outflow resistance is prevented from operating suddenly. -ing

(F) Effects of the Invention With the above-mentioned configuration, the invention has the following effects.

First, since the rod and the damper case are arranged inside the mission case, the sliding portion of the rod does not require anticorrosion treatment such as plating, the damper structure is simplified, and the shock absorber is inexpensive. It came to be obtained.

Second, since the shock absorbing material of the damper is gas, the influence on the temperature change is reduced, and the gear shifting operation can be made uniform.

Thirdly, since the cushioning material does not deteriorate, maintenance can be dispensed with.

Fourth, the gas is elastic so that it will not be locked even if the throttle hole is clogged.

[Brief description of drawings]

FIG. 1 is an internal plan view of an HST type axle drive equipped with a shock absorber of the present invention, FIG. 2 is a side sectional view of the same damper part, and FIG. 3 is a rear sectional view showing another embodiment. P …… hydraulic pump M …… hydraulic motor A …… damper 10 …… mission case 23a ・ 37 …… damper case 32b …… rod

Claims (1)

[Scope of utility model registration request] 1. In an axle drive device in which an HST transmission is arranged in a transmission case 10, a gear shifting arm for rotating a rotating swash plate 25 of the HST transmission and one end of a rod protruding from a damper A. A gear shift shock absorber for an HST transmission, characterized in that the damper A is configured as a gas damper and is disposed outside the lubricating oil in the transmission case 10.