JPH0728035Y2 - Axle drive - Google Patents

Description

[Detailed Description of the Invention] (a) Field of Industrial Application The present invention is applied in a transaxle case for driving an axle.
The present invention relates to a mechanism for returning a speed change lever to a neutral position when a brake pedal is operated in an HST type axle drive device configured to be installed inside an HST speed change device.

(B) Conventional technology Conventionally, in a traveling vehicle equipped with an HST transmission,
A technique in which the shift lever of the ST transmission is configured to reliably hold the neutral position is known.

For example, it is as in Japanese Utility Model Publication No. 63-3527.

(C) Problems to be solved by the present invention In addition to the conventional technique, the present invention is configured such that even when the operator depresses the brake pedal, the shift lever is interlocked to return to the neutral position. Furthermore, the mechanism that links the brake device and the gear shift lever is not exposed to the outside, but is housed inside the transaxle case where the HST gear is arranged, so that a complicated link mechanism is exposed to the outside of the aircraft. It is configured to not exist.

(D) Means for Solving the Problems The purpose of the present invention is as described above, and the configuration for achieving the purpose will be described below.

In the transaxle case M, a hydraulic continuously variable transmission,
In an axle drive device that accommodates an axle 33 connected thereto via a power transmission mechanism and is provided with a brake device that brakes the axle 33, neutralize the hydraulic continuously variable transmission before operating the brake device. An interlocking mechanism for forcibly returning to the position is formed inside the transaxle case M.

Further, the hydraulic continuously variable transmission is configured such that the hydraulic pump P and the hydraulic motor Mo are arranged side by side in a direction parallel to the axle 33, and the hydraulic pressure is applied prior to operating the brake device. When viewed from the top view of the transaxle case M, the interlocking mechanism for forcibly returning the automatic continuously variable transmission to the neutral position is seen from the top view of the transaxle case M, the hydraulic continuously variable transmission, the power transmission mechanism, and the axle 33.
It is arranged in the space surrounded by.

The transaxle case M is composed of at least two upper case M1 and lower case M2 joined together, and forcibly returns the hydraulic continuously variable transmission to the neutral position prior to operating the brake device. The interlocking mechanism is suspended and supported inside the upper case M1.

(E) Embodiments The purpose and configuration of the present invention are as described above. Next, the configuration for achieving the purpose will be described.

FIG. 1 shows a tractor equipped with a mower device or the like as a traveling vehicle. The steering wheel 48 is the front wheel and the driving wheel 47 is the rear wheel.

The axle 33 that drives the drive wheels 47 is supported by the transaxle case M.

The transaxle case M comprises an upper case M1 and a lower case M2, each of which is vertically separable on a line passing through the axis of the axle 33.

The hydraulic continuously variable transmission is arranged inside the transaxle case M, and the interlocking mechanism of the brake device and the speed change operation system, which will be described in detail later, is housed therein.

A pump shaft 40 that drives a hydraulic pump P of the hydraulic continuously variable transmission protrudes above the transaxle case M, and a horizontal pulley 46 fixed to the pump shaft 40 receives a power from an engine (not shown) V It is configured to be transmitted by a belt.

Reference numeral 8 is a link connecting the transmission pedal 28 to the transmission lever 1 (FIG. 2).

The link 7 of the brake pedal 45 is connected to the link 29 of the brake lever 2 via a spring mechanism.

The speed change pedal 28 and the brake pedal 45 are usually arranged in parallel in the left-right direction of the machine body, and in FIG.

FIG. 2 is a plan view of the transaxle case M. A transmission lever shaft 43, a brake lever shaft 18, an interlocking arm shaft 21, and a pump shaft 40 are provided on the upper surface of an upper case M1 that constitutes the transaxle case M so as to project therefrom.

A gear shift lever 1 is fixed to the gear shift lever shaft 43, and a gear shift pedal 28 is connected to the gear shift lever 1 via a link 8.

The brake lever 2 is fixed to the brake lever shaft 18. An arm 22 is fixedly mounted on the interlocking arm shaft 21, and the brake lever 2 is connected to a brake arm 26 via a buffer spring mechanism.

Further, the neutral detection switch 10 projects laterally of the upper case M1, and the hydraulic pressure release lever 42 projects laterally of the lower case M2.

The hydraulic pressure release lever 42 is a lever for hydraulically releasing the function of the HST transmission by hydraulically connecting the discharge passage of the hydraulic pump P and the return oil passage.

Next, description will be given with reference to FIGS.

Inside the transaxle case M, an axle drive device is configured as follows.

That is, the hydraulic continuously variable transmission described above comprises a combination of a variable displacement hydraulic pump P and a fixed displacement hydraulic motor Mo. The hydraulic pump P and the hydraulic motor Mo are attached to the axle 33. While arranging them side by side in a substantially parallel direction,
The pump shaft 40 of the hydraulic pump P and the motor shaft 35 of the hydraulic motor Mo are mounted on the manifold 42 so that the axes thereof are substantially orthogonal to each other.

The rotational speed change and torque of the hydraulic motor Mo to which the hydraulic pressure is supplied from the hydraulic pump P via the manifold 42 are controlled by changing the rotation angle of the movable swash plate 6 of the hydraulic pump P. The motor shaft 35 of the hydraulic motor Mo is connected to the left and right axles 33 via a power transmission mechanism.

The left and right axles 33 have a diff gear device D at the abutting portion.
Are provided and are differentially connected to each other.

The power transmission mechanism includes a gear 36 provided on the motor shaft 35 of the hydraulic motor Mo and a first intermediate gear 37 that meshes with the gear 36.
And a second shaft fixed to the intermediate shaft 65 supporting the first intermediate gear 37.
The intermediate gear 38 and the ring gear 39 of the differential gear device D that meshes with the intermediate gear 38 are configured.

The transaxle case M can be divided into two parts, an upper case M1 and a lower case M2, from a plane position including the motor shaft 35 of the hydraulic motor Mo, the intermediate shaft 65, and the shaft center of the axle 33, each of which is not shown. It is integrally joined by a bolt.

A shaft end portion of the motor shaft 35 of the hydraulic motor Mo projects to the outside of the transaxle case M, and a brake device for braking the axle 33 is provided at this portion.
Reference numeral 34 is a brake drum that is braked by operating the brake arm 26.

On the gear shift lever shaft 43, a movable swash plate rotating arm 5 is fixed to a portion located inside the upper case M1, and a neutral detent arm 3 is further fixed. The tip of the movable swash plate rotating arm 5 is spherical, and is fitted into the arm engaging portion 41 of the kamaboko-shaped movable swash plate 6.

At the engaging portion between the arm engaging portion 41 and the movable swash plate rotating arm 5, there is a margin in the horizontal direction and the vertical direction.

The kamaboko-shaped movable swash plate 6 is slidably fitted along the guide surface of the upper case M1 in the shape of a concave arc at its back.

Since the angle of the movable swash plate 6 changes according to the stepping direction and the stepping amount of the speed change pedal 28, the hydraulic oil is discharged from the hydraulic pump P so as to continuously rotate the hydraulic motor Mo in the forward direction or the reverse direction of the vehicle. is there.

As clearly shown in FIG. 4, when the hydraulic pump P is in the neutral position,
A detent fitting portion 3b is formed on the outer periphery of the neutral detent arm 3 so that the speed change lever 1 can be reliably stopped, and the neutral detent ball 9 is fitted into the detent fitting portion 3b.

The neutral detent ball 9 is biased by a biasing spring 9a, and a push pin 12 is provided between the neutral detent ball 9 and the neutral detection switch 10.

The push pin 12 is in a state in which the hydraulic pump P is driving the hydraulic motor Mo while the neutral detection switch 10 is being pushed, the neutral detent ball 9 is fitted into the detent fitting portion 3b, and the push pin 12 is pushed. The position where is released is the position of the hydraulic pump P.

Next, an interlocking mechanism for forcibly returning the hydraulic continuously variable transmission to the neutral position first when the brake pedal is operated by operating the brake pedal 45 will be described. An interlocking arm 4 is fixed to a portion of the brake lever shaft 18 located inside the upper case M1.

A roller 27 is arranged at one end of the interlocking arm 4, and the roller 27 is fitted into an interlocking long hole 3a provided in the neutral detent arm 3.

When the brake pedal 45 is not depressed, the interlocking long hole 3a is located in the wide groove portion of the roller 27.
The town detent arm 3 has a freely rotatable shape without interfering with.

However, when the brake pedal 45 is depressed with the neutral detent arm 3 rotated to a certain speed change state, the interlocking arm 4
Rotates, and the roller 27 rotates so as to enter the narrow groove portion of the interlocking elongated hole 3a, so that the neutral detent arm 3 is forcibly returned to the neutral position where the detent fitting portion 3b fits into the neutral detent ball 9. It is configured accordingly. Then, the interlock dome 4 is formed with the long hole 4a so as to return the speed change to the neutral position before the brake device is operated, and the link 19
One end of is inserted.

The other end of the link 19 has an axle 33 as shown in FIG.
It is connected to the arm 20 by passing between a bearing portion 63 of the transaxle case M that supports the counter shaft 65 and a bearing portion 64 that supports the counter shaft 65.

The arm 20 is fixed to the brake operation shaft 21 located inside the upper case M1. The brake operating shaft 21 projects outside the upper case M1 and is connected to a brake arm 26 via an arm 22 and a link 25. A buffer spring mechanism is constituted by a spring receiver 23 and a buffer spring 24 between the links 25. The buffer spring mechanism provided in front of the brake arm 26 limits the load applied to the brake arm 26.

The interlocking mechanism described above is arranged in a space surrounded by the hydraulic continuously variable transmission, the power transmission mechanism, and the axle 33 when viewed from the upper surface of the transaxle case M, as shown in FIG.

Since the link 19 is located at one end of the elongated hole 4a, even if the interlocking arm 4 is rotated by depressing the brake pedal 45, the brake device is not operated until the neutral regulating arm 3 returns to the neutral position. It does not work. The brake device does not operate unless the brake pedal 45 is depressed to a certain angle.

When the brake pedal 45 is depressed, the interlocking arm 4 forcibly returns the neutral control arm 3 to the neutral position as described above, and at this time, the link 19 is positioned at the other end of the elongated hole 4a and the interlocking arm 4 is formed. When the interlocking arms 4 engage with each other and further rotate, the link 19 is pulled, and the arms 20, 22,
The brake arm 26 is operated via the link 25 and the spring cushioning mechanism, and the brake drum 34 is controlled to operate the brake device.

The configuration of the hydraulic pump P will be described with reference to FIG.

The hydraulic pump P is fixed to a manifold 42 fixed to the bottom surface of the upper case M1 with bolts. The manifold 42 is formed in an L shape, a hydraulic pump P is attached to the upper surface of the manifold 42, and a hydraulic motor Mo is attached to the side surface.

As described above, the spherical tip portion of the movable swash plate rotating arm 5 is fitted into the arm engaging portion 41 provided on the movable swash plate 6 of the hydraulic pump P.

FIG. 6 shows the shape of the movable swash plate 6.

Fig. 7 shows the brake lever shaft 18 pivotally supported on the upper case M1.
And the interlocking arm 4 and the brake lever 2 fixed to this
Shows the configuration of.

FIG. 8 shows a side sectional view of the neutral detection switch 10, the push pin 12, and the neutral detent ball 9.

The structure will be described in combination with the plan sectional view of FIG.

There is a slight error in the neutral position of the hydraulic pump P due to manufacturing and assembly errors.
There is also a slight error in the position of the detent fitting portion 3b provided in the.

Therefore, at the time of assembly, it is necessary to determine the position of the neutral detent ball 9 in accordance with the position of the individual detent fitting portion 3b.

That is, in FIG. 4, adjustment of the neutral detent ball 9 in the front-back direction of the machine body is performed by loosening the lock nuts 16 and 17 holding the holding plate 13 and inserting the ball case 15 into the insertion hole.
It is rotated inside the 50.

The ball case 15 is, as shown in FIG.
Since the insertion hole for the neutral detent ball 9 is opened at a position eccentric from the center of the, the position of the neutral detent ball 9 changes in an arc by rotating and adjusting the ball case 15. Thickness of the neutral detent arm 3
There is T3, even if the position of the neutral detent ball 9 changes,
It is set to be performed within the range of plate thickness T3.

The eccentric state of the insertion hole of the neutral detent ball 9 with respect to the ball case 15 is clear because the upper and lower wall thicknesses are different from t1 and t2.

The amount of protrusion of the neutral detent ball 9 is adjusted by loosening the lock nuts 16 and 17 and moving the mounting position of the ball case 15 with respect to the holding plate 13 into and out of the fitting hole 50. The holding plate 13 is fixed to the side surface of the upper case M1 with a fixing bolt 14.

FIG. 9 is a plan sectional view showing another embodiment of the interlocking mechanism mounted on the axle drive device, and FIG. 10 is a developed side sectional view along the operation shaft portion.

9 and the embodiment disclosed in FIGS. 9 and 10 are different in the interlocking mechanism between the fine adjustment turning mechanism of the movable swash plate 6 and the neutral holding of the neutral detent arm 3. Part of the device.

In the above-described embodiment, the speed change lever 1 is directly fixed to the speed change lever shaft 43, and the operation angle of the speed change lever 1 is converted into the rotation angle of the movable swash plate rotation arm 5 as it is. Of.

In the embodiment shown in FIG. 9, the speed change lever 1 is first integrated with the arm shaft 53 of the neutral detent arm 3, and the neutral detent arm 3 is rotated directly by stepping on the speed change pedal 28. is there.

A fine shift fine adjustment cam groove 3c is formed in the neutral detent arm 3, and a roller 55 provided on the other end side of the movable swash plate rotating arm 5 is fitted in the fine shift fine adjustment cam groove 3c. .

The shift fine adjustment cam groove 3c is a cam groove in which a change in the operating angle of the movable swash plate rotating arm 5 is gentle when the vehicle starts from the neutral position and the operating angle changes normally after reaching a constant speed. Is there.

The neutral position holding device for the movable swash plate 6 is a roller that is pivotally supported by the neutral position holding cam 50 in the detent fitting portion 3b.
I'm holding 52.

The cam shaft 51 that pivotally supports the neutral position holding cam 50 projects to above the upper case M1 as shown in FIG. 10, and the arm 61 provided at this portion is configured to operate the neutral detection switch 10.

Then, in order to constantly urge the roller 52 of the neutral position holding cam 50 toward the detent fitting portion 3b side, the urging rod 56 and the urging spring 58,
It is arranged inside the upper case M1 in the front-rear direction.

The urging rod 56 is suspended from the upper case M1 by a holding fitting 57.

Further, the manifold 42 is fixedly installed on the lower surface of the upper case M1, but a mounting hole for the upper case M1 of the manifold 42 is provided.
42a, 42a, and 42a are three pieces, and the manifold 42 is made of die-cast casting so that it can be mounted even when the mounting surface is not sophisticated.

Further, as shown in FIG. 10, the portion of the shift lever shaft 43 serves as a pivot shaft, and the movable swash plate rotating arm 5 is loosely fitted to the outer periphery of the shift lever shaft 43. The lower pivot 43a is slightly eccentric, and when the gearshift lever shaft 43 is slightly rotated by a driver, etc., the pivot 43a is rotated.
The center of 43a changes, and the center position of the movable swash plate 6 can be adjusted.

(F) Effect of the Invention Since the present invention is configured as described above, it has the following effects.

Since it is constructed as in claim 1 of the utility model registration, in the prior art, the interlocking mechanism of the brake pedal 45 and the speed change pedal 28 is arranged in the state of being exposed to the outside of the transaxle case.・ There were problems that grass and soil adhered and movement was not smooth, rust created aesthetic loss, and movement became stiff when lubrication grease in that part was lost. In this case, since the interlocking mechanism itself is also housed inside the transaxle case M, the interlocking mechanism can be operated smoothly without the portion exposed to the outside.

Further, by arranging the main parts such as the link, the arm, the roller 27, etc. inside the case, it is possible to prevent lubrication of the link, prevention of rust, and prevention of wear of the sliding part.

Since the utility model registration is constructed according to claim 2, the inside of the transaxle case M, which is formed in a substantially square shape in plan view, is divided into four housing portions, and the HST transmission and the power transmission mechanism are provided for each of them. Since the differential gear device D and the interlocking arm mechanism can be arranged, the overall structure of the transaxle case M can be made compact.

Since the utility model registration is constructed as in claim 3, it is possible to assemble the mechanism for interlocking the speed change pedal 28 and the brake pedal 45, the neutral position holding mechanism, and the neutral position adjusting mechanism on the upper case M1 side. It's done, upper case M1 separately
Since these can be put into a working state and then covered and fixed to the lower case M2, the assembly is simplified.

[Brief description of drawings]

FIG. 1 is a side view of a traveling vehicle equipped with the HST type axle drive device of the present invention, FIG. 2 is a plan view of the HST type axle drive device of the present invention, and FIG. 3 is an upper case of a transaxle case M.
Fig. 4 is a plan view showing the inside of the lower case M2 with M1 removed.
FIG. 5 is a plan view showing an interlocking mechanism of the gear shift lever 1 and the brake device of the HS type transmission, FIG. 5 is a side sectional view of a hydraulic pump P portion of the HST transmission, and FIG. 6 is a perspective view of a movable swash plate 6 of the hydraulic pump P. 7 and 8 are sectional views of the brake lever 2 portion, FIG. 8 is a sectional view of the neutral detent arm 3 and the neutral detent ball 9, and FIG. 9 is another sectional view of the interlocking mechanism mounted on the axle drive device. The cross-sectional plan view showing the embodiment, FIG.
It is a development side sectional view along an operation axis part. M …… Transaxle case 1 …… Shift lever 2 …… Brake lever 3 …… Neutral detent arm 4 …… Interlocking arm 5 …… Movable swash plate rotating arm 6 …… Movable swash plate 28 …… Shift pedal 45 …… break pedal

Claims (3)

[Scope of utility model registration request] 1. A transaxle case M, a hydraulic continuously variable transmission, and an axle 33 connected thereto via a power transmission mechanism.
And an axle drive device provided with a brake device for braking the axle 33, the interlock mechanism for forcibly returning the hydraulic continuously variable transmission to the neutral position prior to operating the brake device. An axle drive device, which is configured inside a case M. 2. The axle drive system according to claim 1, wherein the hydraulic continuously variable transmission is configured such that the hydraulic pump P and the hydraulic motor Mo are arranged in parallel in a direction parallel to the axle 33. In view of a top view of the transaxle case M, the interlocking mechanism for forcibly returning the hydraulic continuously variable transmission to the neutral position prior to operating the brake device is viewed from above the hydraulic continuously variable transmission and the power. An axle drive device arranged in a space surrounded by a transmission mechanism and an axle 33. 3. The axle drive device according to claim 1, wherein the transaxle case M is formed by joining at least two upper cases M1 and lower cases M2,
An axle drive device characterized in that an interlocking mechanism for forcibly returning the hydraulic continuously variable transmission to a neutral position prior to operating the brake device is suspended and supported inside the upper case M1.