JPS5850147Y2 - Seal structure of transmission case - Google Patents

Description

[Detailed explanation of the invention] This invention is based on the seal structure of the mission case.
This invention relates to an improvement in the mounting structure of an oil seal interposed between a transmission case and an operating shaft inserted therein.

In the above-mentioned seal structure, the oil seal has conventionally been located within the wall of the transmission case, and therefore, when attaching and detaching the oil seal, the operating shaft must be inserted and removed, resulting in poor work efficiency.

The present invention aims to solve the above-mentioned problems by rationally improving the mounting structure of the oil cooler, and to provide a sealing structure with high sealing effect.

Next, embodiments of the present invention will be described based on illustrative drawings.

A pair of left and right drive wheels 4, 4 are mounted on a machine frame 2 with an engine 1 mounted on the front thereof via a mission case 3, and a control handle 5 is attached thereto.The mission case 3 is further equipped with an output section. , a connecting portion 6 is attached to the rear of the machine frame 2, thereby configuring a self-propelled vehicle to which a working device such as a tiller (not shown) can be connected.

A driven wheel body 2 that can be slid by a fork 20 is attached to each of the axles 19 and 19 that are moved separately from the axles 4, 4.
1 is spline-fitted with the driven wheel body 21,
A pawl clutch (not shown) is interposed between the engine 1 and a driving wheel body 22 that is interlocked with the engine 1, and the clutch is engaged by the fork 20.

A pair of left and right clutches 7゜7 that separately connect and disconnect power transmission from the engine 1 to both axles 4, 4 by turning the transmission case 3 are internally installed in the transmission case 3, and each fork 20
．． A rotary operating shaft 8.8 for swinging the 20 is protruded from the tension case 3 to the rear of the vehicle body, and each operating shaft 8,
A clutch operating arm 9 is removably fixed to the protrusion of 8 with a bolt 10, and both clutch arms 9
, 9 are provided with a pair of left and right clutch operating levers 11, 11 separately connected by wires to the handle 5.
Said lever 11. Clutch operation shaft 8, 80 according to 'If
By rotating the clutches 7 and 7, both clutches 7 and 7 are connected and disconnected to steer the vehicle body.

Measures to prevent oil leakage from inside the mission case 3 at each of the operating shaft protruding portions of the mission case 3 are constructed as shown in FIG.

That is, an outer end hole portion 12a having a diameter larger than the diameter of the operation shaft 8 is formed at the outer end of the operation shaft insertion hole 12 formed in the transmission case 3, and on the other hand, the operation shaft insertion hole 12a of the transmission case 3 is It has a cylindrical portion 14 having a smaller diameter than the outer diameter of the boss portion 13 in the shaft protruding portion, and a cylindrical portion 15 having a diameter equal to or larger than the outer diameter of the boss portion 13, and the outer diameter of the operating shaft The seal holder 16 has an inner diameter larger than that of the seal holder 16.

Then, both the large and small diameter cylindrical parts 14 and 15 are fitted onto the operating shaft 8, and the large diameter cylindrical part 15 is positioned outside the mission case 3.

Further, with the small diameter cylindrical portion 14 fitted into the outer end hole portion 12a of the operation shaft insertion hole 12 via an elastic material 17 attached to its outer periphery as a sealing and fastening member, the seal holder 16 is inserted into the mission case 3. An oil seal 18 is fitted between the large diameter cylindrical portion 15 and the protruding portion of the operating shaft 8 from the mission case 3.

First, the oil seal 1B is configured to be interposed between the mission case 3 and the operating shaft 8 via the seal holder IS in a state where the oil seal 1B is located outside the mission case 3, and the oil seal 18 is attached and detached. In this case, the clutch operating arms 9, 9 are detached from the operating shafts 8, 8, and are integrally attached to and detached from the transmission case 3 with the seal holder 16.

In summary, the seal structure of the □ tension case according to the present invention is such that an outer end hole portion with a larger diameter than the operating shaft is formed at the outer end of the operating shaft insertion hole formed in the □ tension case, and a smaller diameter A seal holder having a cylindrical portion and a large-diameter cylindrical portion is provided, and the small-diameter cylindrical portion is fitted into the outer end hole portion of the operation shaft insertion hole through an elastic material attached to the outer periphery of the small-diameter cylindrical portion. It is characterized in that it is fixedly attached to the transmission case and that an oil seal is fitted between the large-diameter cylindrical portion and the operating shaft.

In other words, with the oil seal holding part, which is a large-diameter cylinder, located outside the transmission case, the oil seal is installed between the transmission case and the operating shaft via the seal holder configured to be installed on the transmission case. Therefore, the oil seal can be installed and removed simply by installing and removing the seal holder without inserting and removing the operating shaft as in the past, and this work can be done more efficiently. is attached to the outer end hole of the operating shaft insertion hole through an elastic material, so even if the operating shaft insertion hole and the seal holder are misaligned, the surface of the oil seal relative to the operating shaft The pressure can be made uniform over substantially the entire circumference.

If the operating shaft insertion hole and the seal holder are misaligned, one side of the oil seal will be strongly compressed, which tends to cause uneven sealing performance. Since the holder is fitted into the outer end of the operation shaft insertion hole, it can be moved to the compressed side, so the surface pressure of the oil cooler on the compressed side can be reduced, and as a whole, the oil The surface pressure of the seal can be made approximately equal, and the sealing effect can be improved.

[Brief explanation of the drawing]

The drawings show an embodiment of the seal structure of the transmission case according to the present invention, and FIG. 1 is an overall side view of the self-propelled vehicle, and FIG. 2 is a sectional view showing the main parts. 3...Mission case 8...Operation shaft, 12...Operation shaft insertion hole, 12a...
・Outer end hole part, 14... Small diameter cylinder part, 19...
...Large diameter cylinder part, 16...Cool holder 1
7...Rubber 18...Oil seal O

Claims (1)

[Claims for Utility Model Registration] ■ At the outer end of the operation shaft insertion hole 12 formed in the mission case 3, an outer end hole portion 12a having a diameter larger than that of the operation shaft 8 is formed, and a small diameter cylindrical portion 14 is formed. A seal holder 16 having a large-diameter cylindrical portion 15 is inserted into the outer end hole portion 12a of the operating shaft insertion hole 12 via an elastic member 17 attached to the outer circumference of the small-diameter cylindrical portion 14. A seal structure for a mission case, characterized in that the oil seal 18 is fitted between the large diameter cylindrical portion 15 and the operating shaft 8. (2) The seal structure for a mission case according to claim 1, wherein the operating shaft 8 is a rotary operating shaft.