JPH0451243Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention is mainly used mounted on a lawn tractor, etc., and the pulley shaft is fitted and supported in the opening of the transmission case via a bearing. This invention relates to a transmission in which a pulley boss of a pulley is fitted to the outer end of the shaft.

[Conventional technology]

Conventionally, in the structure of this type of transmission, a pulley shaft is fitted and supported in the opening of the transmission case via a bearing, and the inner circumferential surface of the opening and the outer circumferential surface of the pulley shaft are connected outwardly by the bearing. It was common practice to fit an oil seal into the gap between the oil seal and the pulley boss at the outer end of the pulley shaft located further outside the oil seal and outside the transmission case.

[Problem that the invention attempts to solve]

Therefore, the pulley boss is located outside the transmission case, which requires a larger area for the pulley to occupy, and the length of the pulley's protrusion is longer than the bearing of the pulley shaft. There was a problem in that the bending moment acting on the pulley shaft due to the belt tension applied to the pulley became large, and the diameter of the pulley shaft had to be increased.

The purpose of this invention is to make a simple modification to the oil seal mounting structure to suppress the protrusion length that protrudes further from the pulley shaft bearing support part to the outside of the transmission case, thereby solving the problems of the conventional structure. The point is to provide something.

[Means for solving problems]

The feature of the present invention is that the transmission equipped with the pulley as described above is configured as follows. That is, the pulley shaft is fitted and supported in the transmission case opening via a bearing, and the pulley shaft is positioned outward from the bearing, and
A pulley boss with a diameter smaller than the opening is fitted, and the pulley boss is attached to the pulley boss mounting part.
The part of the pulley boss on the bearing side is extended toward the bearing side, and an oil seal is provided in the gap between the outer circumferential surface of this extended part and the inner circumferential surface of the opening, and the inner circumferential surface of the extended part of the pulley boss and the outer circumference of the pulley shaft are provided. an O-ring is provided between the pulley body and the pulley body, and the pulley body is formed such that the belt groove of the pulley body is located closer to the bearing side than the attachment portion of the pulley boss in the direction along the pulley axis. be.

[Effect]

If configured as described above, the extended portion of the pulley boss 28 will enter into the opening 19A of the mission case 19, as shown in FIG. 1, for example.

Therefore, in this state, the outer circumferential surface 28A of the extended portion of the pulley boss 28 and the inner circumferential surface 19a of the opening 19A
By providing the oil seal 30 between the two, the length of the pulley boss 28 can be made relatively long, and at the same time, the length of the pulley shaft 34 protruding from the opening 19A can be shortened, thereby providing a seal structure.

By extending the pulley boss in this way, the attachment strength of the pulley boss to the pulley shaft can be made sufficient. By shortening the protruding length of the pulley shaft from the opening, even if belt tension is applied to the pulley shaft, the bending moment due to this tension can be suppressed, so there is no need to make the pulley shaft particularly thick.

Furthermore, as shown in FIG. 1, by inserting the pulley boss 28 into the opening 19A of the transmission case 19, the pulley body 29 can be brought closer to the transmission case 19, so the space occupied by the pulley body 29 is can also be reduced.

Assume that the pulley main body 29 and the pulley shaft 34 swing left and right due to vibrations from the belt side or the transmission case side. In this case, the pulley body 29 and the pulley shaft 34 are in a state where they can swing left and right about the bearing 23 as a fulcrum.

Therefore, as shown in FIG. 1 of the present invention, the belt groove 29A of the pulley body 29 is placed at the position of the bearing 23, which is the fulcrum of the aforementioned runout and has the smallest runout in the direction along the pulley shaft 34 (vertical direction in the paper). It is set close to each other. As a result, even if the pulley body 29 and the pulley shaft 34 swing from side to side, the swing of the belt groove 29A will be smaller compared to a belt groove provided at the same position as the attachment part of the pulley boss, resulting in large tension fluctuations in the belt. There is no possibility that the belt will become loose or come off from the belt groove 29A.

[Effect of idea]

As described above, by lengthening the pulley boss and suppressing the protruding length of the pulley shaft, we were able to maintain sufficient strength against bending moments from the belt and at the same time make the area around the pulley body more compact. .

Even if the pulley body and pulley shaft swing from side to side, the swing of the pulley groove can be suppressed, and situations such as belt tension fluctuations or the belt coming off can be prevented. I was able to do that.

〔Example〕

As shown in Figure 4, there is a bonnet 1 at the front of the aircraft.
The machine body is equipped with an engine 2 and a fuel tank 3 inside, and has a control section 7 with a control handle 4, a driver's seat 5, and a flat deck 6 on the left and right sides at the rear, and is supported by front and rear wheels 8 and 9 for harvesting. Able to run,
A lawn tractor is provided with a mower 10 located between the front and rear wheels 8 and 9, and a grass collection duct 11 and a grass collector 12 that are located between the left and right rear wheels 9 and 9 and extend rearward from the mower 10. has been configured.

To explain the transmission mechanism in detail, output pulleys 14 and 15 are arranged in upper and lower stages on the downward output shaft 13 of the engine 2.
The lower output pulley 15 and the input pulley 16 fitted to the input shaft of the mower 10 are connected by a belt 17 to form a working device transmission mechanism. On the other hand, an input pulley 20 of a transmission case 19 is connected to the upper output pulley 14 via belts 21 and 22 via a continuously variable belt transmission 18, and rear wheels 9 and 9 pivotally supported at the lower end of the transmission case 19 are connected to the upper output pulley 14. It is constructed into a traveling transmission system so that it can be driven.

The mission case 19 will be explained in detail. An input pulley shaft 34 with an input pulley 20 fitted thereon is supported in a protruding manner on the upper surface of the transmission case 19, and a first transmission shaft 36 which is transmitted between the input pulley shaft 34 and the bevel gear 35 is supported. A second transmission shaft 37, an intermediate shaft 38, and a rear wheel shaft 3 are installed on the lower side of the transmission.
9 is placed. A driving sprocket 40 integrally formed with the first transmission shaft 36 and a large and small two-stage gear 41 are spline-fitted to the first transmission shaft 36, and
A large and small two-stage gear 42 that can slide in the axial direction and also serves as a clutch sleeve is spline-fitted to the second transmission shaft 37, and a passive sprocket 43 is loosely fitted therein, and a drive sprocket 44 is spline-fitted therein. . Shift lever 4 of the large and small two-stage gear 42
The forward high speed is achieved by switching the engagement with the large and small two-stage gear 41 by sliding movement in conjunction with the switching operation of step 5.
F ₂ , neutral position N, forward low speed F ₁ , neutral position N, and reverse position R. During this backward movement, the gears 42 are shifted from the large and small gear 42 to the passive sprocket 4.
Reverse transmission is possible by fitting an engaging pin 46 protruding toward the third side with engaging holes 43a provided at multiple locations in the circumferential direction of the passive sprocket 43. The engagement hole 43a is formed into an elongated hole that is elongated in the circumferential direction, so that it can be smoothly engaged with the pin 46. The output shifted by the above configuration is transmitted through the large diameter passive sprocket 4 integrally formed with the drive sprocket 44 and the intermediate shaft 38.
7, and by the chain 51 transmission between the small diameter drive sprocket 48 integrally formed on the intermediate shaft 38 and the input sprocket 50, which is one of the input rotating bodies integrally fitted to the differential case 49, The power is transmitted to a rear wheel shaft 39 that supports the rear wheels 9, 9.

In the figure, 26 is a brake device, which is operated in conjunction with the operation of the main clutch pedal 27.

To explain the structure of the input part of the mission case 19 in detail, the input part of the mission case 19 is provided with a projecting opening 19A that opens outward, and two sets of large and small bearings 2 are installed in this opening 19A.
A pulley shaft 34 is supported by 3 and 24.

As shown in FIG. 1, a pulley boss 28 is spline-fitted to the upper end of the pulley shaft 34 in the drawing.
It is fixed with a bolt 25 to prevent it from coming off. In this pulley boss 28, the bearing 23
The side portion extends toward the bearing 23 (downward in the drawing) and enters the opening 19A.

An oil seal 30 is provided between the outer peripheral surface 28A of the extended portion of the pulley boss 28 and the inner peripheral surface 19a of the opening 19A. An O-ring 31 is provided between the outer peripheral surface of the shaft 34 and the inner race 23a of the bearing 23.
Further, shim members 32 for adjustment are provided on the upper and lower sides of the bearing 23 in the drawing.

In the pulley main body 29 that is bolted to the attachment part 28B of the pulley boss 28, the belt groove 29
so that A is at approximately the same position as the bearing 23 in the direction along the pulley shaft 34 (in the vertical direction on the page).
The pulley body 29 is bent and molded.

[Another example]

The above embodiments can also be applied to general vehicles other than lawn tractors.

[Brief explanation of the drawing]

The drawings show an embodiment of the transmission according to the present invention; FIG. 1 is a longitudinal cross-sectional view showing the input pulley shaft, FIG. 2 is a cross-sectional plan view of the entire transmission case, and FIG. FIG. 4 is a side view of the lawn tractor. 19... Mission case, 19A... Opening of mission case, 19a... Inner peripheral surface of opening, 23... Bearing, 28... Pulley boss,
28A...Outer peripheral surface of the extension part of the pulley boss, 28
B...Pulley boss attachment part, 29...Pulley body, 29A...Belt groove of pulley body, 30...
Oil seal, 31...O ring, 34...Pulley shaft.

Claims (1)

[Scope of utility model registration request] Insert the pulley shaft 34 into the transmission case 19 opening 1
9A via the bearing 23, and a pulley boss 28, which is positioned outwardly from the bearing 23 and has a smaller diameter than the opening 19A, is fitted onto the pulley shaft 34.
Attachment part 28 of pulley boss 28 to which 9 is attached
Pulley boss 2 closer to the bearing 23 than B
8 is extended toward the bearing 23 side, and an oil seal 30 is provided in the gap between the outer peripheral surface 28A of this extended portion and the inner peripheral surface 19a of the opening 19A, and the inner periphery of the extended portion of the pulley boss 28 is An O-ring 31 is placed between the surface and the outer peripheral surface of the pulley shaft 34.
and the belt groove 2 of the pulley body 29
A transmission in which the pulley body 29 is formed such that the pulley body 9A is located closer to the bearing 23 than the mounting portion 28B of the pulley boss 28 in the direction along the pulley shaft 34.