JPH0313102B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a parking brake device for an agricultural tractor having a hydraulically operated travel brake.

(b) Prior Art Conventionally, in a vehicle operation pedal attachment device, a technique is known in which a plurality of arms serve as a pivot shaft.

For example, there is a technique described in Japanese Utility Model Publication No. 40-3138.

(c) Problems to be solved by the invention When using a mechanical travel brake device such as an internal expansion type brake, a locking device for maintaining the brake pedal of the travel brake device in a depressed state is required. If installed, it can also be used as a parking brake, but in the case of agricultural tractors with hydraulic travel brakes, even if you keep your foot on the brake pedal, the brakes will gradually loosen due to pressure oil leaks. If you stop it on a slope, etc., it will start.

In order to prevent this, agricultural tractors equipped with a hydraulic travel brake system are provided with a separate mechanical parking brake system. The present invention is intended to more simply configure this parking brake device.

In particular, the pivot shaft of the arm of the parking brake device,
By using it as the pivot shaft for the arm of the defrock pedal located nearby, the protrusion to the side wall of the transmission case can be reduced, and the cover of the creep transmission mounted on the side wall can be easily assembled. This is what I did.

(d) Means for solving the problems The problems to be solved by the present invention are as described above.
Next, means for solving the problem will be explained.

The pivot shaft 82 of the differential gear pedal 65 also serves as the pivot shaft of the arm 64 of the parking brake lever 62, and the pivot shaft 82 is connected to the cover body 60 of the creep transmission.
The push-up pin 67, which is arranged below the parking brake lever 62 and which is operated by the arm 64 of the parking brake lever 62, is connected to the cover body 60, with the arm 64 pivoted inwardly on the pivot shaft 82, and the defrock pedal 65 pivoted outwardly. An adjustment bolt 68 is interposed between the push-up pin 67 and the arm 64, and a parking brake device is disposed inside the cover body 60 of the creep transmission.

(E) Embodiment The problems to be solved by the present invention and the means for solving the problems are as described above. Next, the structure of the embodiment shown in the attached drawings will be explained.

FIG. 1 is a side sectional view of a transmission device for an agricultural tractor according to the present invention.

A clutch housing 1 is fixed to the rear surface of an engine of an agricultural tractor, a center plate 57 is sandwiched between the rear surfaces of the clutch housing 1, and a rear axle case 3 is fixed to the rear surface of a transmission case 2.

The rear half of the clutch housing 1 communicates with the inside of the transmission case 2 and rear axle case 3 to form an oil bath type transmission chamber.

Engine power is transmitted through the main clutch in the clutch housing 1 to the transmission chamber by an input shaft 11. The input shaft 11 is of a cantilever type and protrudes into the transmission chamber, and a fixed gear 15 at the rear end meshes with two loosely fitted gears 16 and 17 on the hydraulic clutch shaft 12.

The other 17 serves as a loose-fitting gear of the hydraulic clutch device 21a and a loose-fitting gear that meshes with the fixed gear 23 of the main speed change counter shaft 13.

Four fixed gears 2 on the main shift counter shaft 13
3, 24, 25, 26 are provided, and three of them 23, 25, 26 are always in mesh with loosely fitted gears 17, 18, 20 of the hydraulic clutch for main transmission. A reversing gear 19 is interposed between the fixed gear 26 and the loosely fitted gear 20.

Hydraulic clutch device 2 is activated by operating the hydraulic control valve.
1a, 21b, 22 is selected, and the forward 2
1 speed and 1 reverse speed. Since the rotation after the main shift is transmitted onto the hydraulic clutch shaft 12, this hydraulic clutch shaft 12 is extended and is also used as a hydraulic clutch shaft of the sub-transmission device constituted by the hydraulic clutch devices 38a and 38b.

Of course, since it is one shaft, the axis of the hydraulic clutch of the main transmission and the axis of the hydraulic clutch of the auxiliary transmission coincide, and furthermore, the axes of the auxiliary transmission counter shaft 35 and the main transmission counter shaft 13 also coincide. It is configured as much as possible. A one-way clutch 34 and a hydraulic pump 4 are interposed between these two front and rear counter shafts.

The low speed of the auxiliary transmission is controlled by the connection of the hydraulic clutch device 38a.
0→axis 43.

The high speed is transmitted from the hydraulic clutch shaft 12 to the hydraulic clutch device 38b to the fixed gear 40 to the shaft 43.
A creep shift is further performed between the shaft 43 and the shaft 36.

When the sliding gear 44 is slid backwards as shown by the solid line in FIG. 1, the shafts 43 and 36 are connected and the speed is normal.

In the case of creep speed, when the sliding gear 44 is slid forward, the fixed gear 4 and the sliding gear 44 mesh, and the fixed gear 42 is moved from the creep counter shaft 42.
a to the fixed gear 72 on the shaft 36. The fixed gears 72, 45, 36a on the shaft 36, the loosely fitted gears 47, 49 on the pinion shaft 37, and the spline sliding gear 48 perform the final shift between high, medium and low. 46 is a parking brake drum.

PTO shifting is carried out between the main shift counter shaft 13 and the PTO
The transmission is performed in four stages between the transmission shafts 14. That is, the four fixed gears 23, 2 on the main speed change counter shaft 13
4, 25, 26 and the loosely fitted gears 27, 28, 29, 30 on the PTO transmission shaft 14 are always in mesh with each other, and by sliding the transmission sliders 75, 76 back and forth, four-stage transmission is performed by color shift. . The rotation after the speed change is transmitted to the PTO shafts 77 and 10 via the coupling.

Ground between PTO shaft 77 and PTO shaft 10
PTO switching is performed. By moving the sliding gear 9 forward as shown in Fig. 1, the PTO shaft 77
When the PTO shaft 10 is connected to perform normal PTO rotation and the sliding gear 9 is moved backward, the internal gear 53
It engages with the ground PTO and rotates.

The ground PTO rotation is carried out from the fixed gear 50 of the pinion shaft 37 to the loosely fitted gear 51 on the PTO shaft 10.
Then, it is transmitted to the internal gear 53. Also, loose fit gear 5
2, the front wheel power take-off shaft 78 is meshed with the loosely fitted gear 54 to rotate.

When the clutch shifter 55 is moved backward, it engages with the collar shift portion of the loosely fitted gear 54 and drives the front wheel power take-off shafts 78 and 31.

A PTO clutch device between the PTO shaft 10 and the PTO shaft 6 is composed of a clutch case 7, a friction plate 8, a spring 56, and the like.

This clutch case 7 is slid back and forth in conjunction with the vertical movement of the hydraulic lift arm for lifting and lowering the work machine.
First, the friction plate 8 connects and disconnects the clutch, and then the clutch case 7 and the spline body 7a connect and disconnect the meshing clutch.
The PTO clutch device is designed to reduce shocks during engagement.

FIG. 2 is a side view of the parking brake device of the present invention;
FIG. 3 is a front sectional view, and FIG. 4 is a bottom view.

The parking brake device applies braking by tightening a parking brake drum 46, which is fixed to the front part of a pinion shaft 37, with a band 81, as shown in FIG. One end of the band 81 is locked to a pin 92 on a protruding wall from the rear axle case, and the other end is locked to one end of the bell crank 80 after winding around the parking brake drum 46.

This bell crank 80 has rear axle case 3
The bell crank 80 protrudes from an opening provided in the wall for mounting the creep device, and a push-up pin 67 contacts the other end of the bell crank 80 from below.

The push-up pin 67 is fitted into a hole in the lid 60 of the opening of the creep transmission and is configured to slide up and down to operate the bell crank 80.

An adjustment bolt 68 for adjusting the brake operation stroke is interposed between the arm 64 of the parking brake lever 62 and the push-up pin 67.

That is, the adjustment bolt 68 is used to adjust the operating amount of the push-up pin 67 when the parking brake band 81 is extended.

The push-up pin 67 is pushed from the upper end of the adjustment bolt 68 of the arm 64 when the parking brake lever 62 is pulled upward, the link 63 is pulled, and the arm 64 is rotated upward.

The push-up pin 67 is fitted into the cover body 60 of the opening for creep transmission insertion.

Further, the arm 64 of the parking brake lever 62 is loosely fitted inside the pivot shaft 82, and the arm 64 of the parking brake lever 62 is loosely fitted inside the pivot shaft 82.
A midway portion of the defrock pedal 65 is also pivotally supported at 2. On the pivot shaft 82, the arm 64 of the parking brake lever 62 is on the inside, and the differential pedal 6 is
5 is pivoted on the outside.

When the differential gear pedal 65 is depressed, the link 66 is raised, and an arm 87 fixed to the differential shifter shaft 83 is rotated upward.

FIG. 5 is a plan cross-sectional view of the defrock shifter section.

When the shifter shaft 83 rotates, the pin 85 rotates and pushes the cam surface of the differential shifter 84, which cannot rotate.
move to the left.

This engages the differential lock pin and locks the differential gear. A return spring 86 serves to return the differential shifter 84 to its original position when the differential pedal is released. 88 is a rear axle housing.

In the creep transmission, bearing protrusions 69a and 69b protrude inward from the lid 60 into the rear axle case 3, and the creep counter shaft 42 and shifter shaft 99 are supported by these bearing protrusions. A fixed gear 41 and a carved gear 42a for creep speed change are provided on the creep counter shaft 42.

The shifter 71 on the shifter shaft 99 allows the shaft 4
The sliding gear 44 on the top 3 is moved back and forth to perform creep shifting. A creep shift lever protrudes from a hole 61 above the lid 60, and the shifter 71 and sliding gear 44 are moved by rotation of the creep shift lever.

Bell crank 80 of the parking brake device of the present invention
The shaft of the arm and the push-up pin, which are protruded using the opening for the creep transmission and are moved by the parking brake lever 62, are supported by the lid 60.

FIG. 6 is a side view showing a configuration in which the parking brake lever arm pivot shaft 89 and the differential lock pedal 65 pivot shaft 98 are not used together, and FIG. 7 is a front view.

In this case, arm 6 of the parking brake lever
At step 4, the rotating arm 90 at the tip of the pivot shaft 89 protruding into the inside of the lid body is rotated upward to tighten the brake band.

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

First, since the arm pivot shaft for the defrock pedal and the parking brake arm are also used, the number of pivot shafts that protrude outward from the side of the transmission case or rear axle case can be reduced. It is possible to reduce the number of holes, protrusions, and other parts that require additional machining processes on the transmission case and rear axle case, which are large cast parts.
It is possible to lower processing costs and reduce casting errors in casting materials.

Second, in the case of the prior art configuration shown in FIG. 6, the arm 64 of the parking brake interferes with the differential pedal 65, so the cover 60 that constitutes the creep transmission device does not touch the differential pedal. It could not be removed without removing it.

However, as in the present invention, since both are pivoted together on the pivot shaft 82, the arm 64 is at the bottom,
By slightly depressing the differential pedal 65, the cover of the creep transmission can be removed from the abutting portion of the push-up pin and adjustment bolt.

Third, the arm 64 of the parking brake lever 62
Since an adjustment bolt 68 is interposed between the brake lever and the push-up pin 67, the brake operation stroke can be adjusted by the adjustment bolt 68.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view of a transmission device for an agricultural tractor of the present invention, FIG. 2 is a side view of a parking brake device of the present invention, FIG. 3 is a front sectional view, FIG. 4 is a bottom view, and FIG. The figure is a cross-sectional plan view of the differential shifter section, Figure 6 is a side view showing a configuration in which the parking brake lever arm pivot shaft and the differential pedal pivot shaft 98 are not used together, and Figure 7 is a front view. be. 62... Parking brake lever, 64... Parking brake lever arm, 65... Defrok pedal, 65a... Defrok pedal arm, 8
2... Pivot axis.

Claims (1)

[Claims] 1 The pivot shaft 82 of the differential lock pedal 65 serves as the pivot shaft of the arm 64 of the parking brake lever 62, and the pivot shaft 82 is connected to the cover body 60 of the creep transmission.
The push-up pin 67, which is arranged below the parking brake lever 62 and which is operated by the arm 64 of the parking brake lever 62, is connected to the cover body 60, with the arm 64 pivoted inwardly on the pivot shaft 82, and the defrock pedal 65 pivoted outwardly. A parking brake device for an agricultural tractor, characterized in that the parking brake device is fitted into and supported by a push-up pin 67 and an arm 64, an adjustment bolt 68 is interposed between a push-up pin 67 and an arm 64, and a parking brake device is disposed inside a cover body 60 of a creep transmission device. .