JPH06298055A - Parking brake device for running vehicle - Google Patents

Abstract

PURPOSE:To lock a front wheel at engine stop, in a parking brake device for a running vehicle such as a tractor, by forming an engaging part on the piston of a hydraulic clutch, and also an engaged part to be engaged with the engaging part by pushing back the piston to a transmission shaft by a return spring. CONSTITUTION:A front wheel transmission system is branched from a rear wheel transmission system having a hydraulic clutch 3, and a transmission shaft 9 for regularly forming the interlocking relation to a front wheel is interposed in the hydraulic clutch 3. The hydraulic clutch 3 has a piston 60 which is pushed against a return spring 63 by the oil pressure supply to an oil chamber 47, and an engaging part 61 is formed on the transmission shaft 39 side. On the other hand, an engaged part 62 engaged with the gear part 61 by returning back the piston 60 by the return spring 63 is formed on the transmission shaft 39 side. When a rear wheel parking brake mechanism is operated, thus, the hydraulic clutch 3 is brought into the engaged state, and the rotation of the front wheel is also locked to ensure the parking.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a parking brake device for a traveling vehicle such as a tractor.

[0002]

2. Description of the Related Art For example, in the case of a tractor having a hydraulic clutch in a rear wheel transmission system, when the engine is stopped, the hydraulic clutch is disengaged, and the rear wheel cannot be braked by the engine. A rear wheel parking brake mechanism is provided on a rotating shaft that is always linked to the rear wheel, and the rear wheel parking brake mechanism is operated by a parking brake operating means.

[0003]

In the above-mentioned prior art, in the case where the front wheel transmission system has a hydraulic clutch, when this hydraulic clutch is in the disengaged state, the rear wheels can be rotationally locked but the front wheels cannot be rotationally locked. It is difficult, and when a heavy work implement is installed in the front like a tractor equipped with a front loader, the load applied to the rear wheels is reduced, and it may shift when parked on a slope. .

By the way, the hydraulic clutch of the front wheel transmission system is
As shown in FIG. 3, the first and second hydraulic packs 3A, 3B are located on both sides of the clutch body 40 in the axial direction, and each hydraulic pack 3A, 3B supplies a pressure oil to the oil chamber 48 to move the piston 49. By pushing against the return spring 50, the friction plate 51 and the clutch plate 52 are pressed to enter the clutch state, and the pressure oil supply to the oil chamber 48 is stopped, the return spring 50 returns the piston 49. The clutch is disengaged.

An electromagnetic switching valve 53 for supplying pressure oil to each oil chamber 48 is connected to the first and second hydraulic packs 3A and 3B, and when one of the electromagnetic switching valves 53 is turned on, the second hydraulic pack 3B enters the state. Thus, the rotation of the first transmission shaft 38 is directly transmitted to the second transmission shaft 39, at which time the other electromagnetic switching valve 53 is turned off and the other electromagnetic switching valve 53 is turned off.
When the first hydraulic pack 3A is turned on, the rotation of the first transmission shaft 38 is transmitted to the second transmission shaft 39 via the gears 41 and 43, the rotation shaft 7 and the gears 44 and 42, and both electromagnetic switching is performed. When the valve 53 is turned off, the power transmission from the first transmission shaft 38 to the second transmission shaft 39 is cut off. That is, when the engine is stopped and both electromagnetic switching valves 53 are turned off, the front wheels are in an idle state, and even if the rear wheels are rotationally locked, the front wheels cannot be rotationally locked.

According to the present invention, a hydraulic clutch for transmitting and disconnecting power to a front wheel is formed, and a meshing portion is formed on the piston and a meshed portion is formed on the front wheel transmission shaft side. When the hydraulic pressure is supplied, the piston is pushed to engage the meshing portion. When the engine is stopped, the front wheels can be rotationally locked by disengaging the clutches to the clutch disengaged state, and when the hydraulic pressure is stopped, the piston is returned by the spring force and the meshing part meshes to enter the clutch. An object is to provide a parking brake device for a vehicle.

[0007]

A concrete means for solving the problem in the present invention is to hydraulically branch a rear wheel transmission system having a hydraulic clutch 2 to a transmission shaft 39 which is always interlocked with a front wheel. A front wheel transmission system for transmitting power through the clutch 3 in a freely connectable / disconnecting manner is formed, and a rear wheel parking brake mechanism 5 is provided on a rotating shaft 4 which is always interlocked with the rear wheel. In the parking brake device for a traveling vehicle in which the piston 60 can be pushed against the return spring 63 by supplying the pressure oil to the oil chamber 48, the hydraulic clutch 3 forms the meshing portion 61 on the piston 60, and the transmission is performed. The piston 60 returns to the shaft 39 side and the spring 63
That is, a meshed portion 62 that meshes with the meshing portion 61 by being pushed back by is formed.

[0008]

When the traveling vehicle is stopped and the parking brake operating means is operated, the rear wheel parking brake mechanism 5 is operated to lock the rotary shaft 4 so as not to rotate, and the electromagnetic switching valve 53 is turned off, so that the hydraulic clutch 3 is operated. The pressure oil supply to the is stopped. When the supply of pressure oil to the second hydraulic pack 3B of the hydraulic clutch 3 is stopped, the piston 60 is pushed from the clutch disengaged state to the clutch engaged state by the urging force of the return spring 63, and the meshing portion 61 of the piston 60 moves. It meshes with the meshed portion 62 formed on the second gear 42 that is integral with the second transmission shaft 39, and the clutch is engaged. As a result, the second transmission shaft 39, which is always interlocked with the front wheels, moves the rotation shaft 4
The first transmission shaft 38 is directly connected to the first transmission shaft 38, and the rotation shaft 4 is rotationally locked by the rear wheel parking brake mechanism 5, so that the front wheels are also locked.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. In FIGS. 1 to 3, reference numeral 11 denotes a transmission case constituting a vehicle body of a traveling vehicle such as a tractor, in which a traveling system and a PTO system transmission are arranged, and a front portion of the transmission case via a clutch housing portion 12. Is connected to the engine E. 13 is a flywheel,
It is directly connected to the PTO propulsion shaft 14, and is connected to the traveling propulsion shaft 15 via the main clutch 16 so that power can be connected and disconnected.

The traveling power transmission system includes a hydraulic propulsion shaft 15 to a hydraulic switching type high / low speed changing mechanism 18 having a hydraulic clutch 17, a 5-speed manual switching main speed changing mechanism 19, and a hydraulic switching type forward / backward traveling having a hydraulic clutch 2. It has a switching mechanism 20, a manual switching-type auxiliary transmission mechanism 21, etc., and is capable of transmitting power from the bevel pinion shaft 22 to the left and right rear wheels via the rear wheel differential mechanism 23. I can say.

The transmission gear 2 is attached to the bevel pinion shaft 22.
5 is provided and always meshes with the gear 26 of the rotary shaft 4. The rotary shaft 4 is capable of transmitting power to a hydraulic switching type front wheel drive / double speed switching mechanism 27 having a hydraulic clutch 3. Power is transmitted from the drive / double speed switching mechanism 27 to the front wheels via the transmission shaft 28. These are front wheel transmission systems, and the power branched from the rear wheel transmission system is transmitted via the gears 25 and 26.

A transmission mechanism having a hydraulic clutch is not provided between the bevel pinion shaft 22 and the rear wheels. Therefore, the hydraulic clutch 2 (or the hydraulic clutch 17 may be used) is disengaged. Even if the interlocking relationship between the engine 22 and the engine E is cut off, the rotary shaft 4 is in an interlocking relationship such that it can always rotate integrally with the rear wheels, and the rear wheel parking brake mechanism 5 is provided on the rotary shaft 4. Has been.

In the rear wheel parking brake mechanism 5, a plurality of friction plates 30 are spline-fitted to the rotary shaft 4, and the friction plates 30 can be sandwiched between a brake pad 32 provided on a brake case 31 and a brake plate 33. The cam 34 presses these to lock the rotation of the rotary shaft 4. The brake case 31 having the brake pad 32 and the brake plate 33 is a unit, and can be inserted into the inside of the transmission case 11 from the side surface thereof.
It also supports a cam shaft 35 that rotates. This camshaft 35
A lever 36 is fixed to and is rotated by a Bowden wire and parking brake operating means (not shown).
A return force is applied to the lever 36 by a spring.

The front wheel drive / double speed switching mechanism 27 is provided between a first transmission shaft 38 directly connected to the rotary shaft 4 and a second transmission shaft 39 directly connected to the transmission shaft 28, and in parallel with these shafts. A rotary shaft 7 is arranged as a counter shaft. The clutch body 40 of the hydraulic clutch 3 is fixed to the first transmission shaft 38, the first gear 41 is loosely fitted to the first transmission shaft 38, and the second gear 42 is fixed to the second transmission shaft 39. The pack selectively fixes the first gear 41 and the second gear 42 to the clutch body 40.
Third and fourth gears 43 and 44 are fixed to the rotary shaft 7, the third gear 43 meshes with the first gear 41, and the fourth gear 4
4 is always meshed with the second gear 42.

That is, the hydraulic clutch 3 has first and second hydraulic packs 3A, 3B. The first hydraulic pack 3A is a multi-plate type for front wheel double speed, as in the prior art, and when in the engaged state, The first gear 41 is fixed to the clutch body 40, and the power of the first transmission shaft 38 is transmitted to the second transmission shaft 39 by increasing the speed of the power of the first transmission shaft 38 in two stages via the rotary shaft 7, and the front wheel is about twice as large as the rear wheel. Drive at peripheral speed. The second hydraulic pack 3B is a mesh type for the front wheel constant velocity, and when in the engaged state, the second gear 39 is fixed to the clutch body 40, and the power of the first transmission shaft 38 is directly transmitted to the second transmission shaft 39. , Drive the front wheels at approximately the same circumferential speed as the rear wheels.

There is no speed change mechanism having a hydraulic clutch between the second transmission shaft 39 and the front wheels. Therefore, either of the first and second hydraulic packs 3A and 3B of the hydraulic clutch 3 is engaged. Then, since the second and fourth gears are always meshed with each other, the first transmission shaft 38 is in an interlocking relationship such that it can always rotate integrally with the front wheel.
When the rotary shaft 4 directly connected to 8 is locked by the rear wheel parking brake mechanism 5, the front wheels are also locked.

The first and second hydraulic packs 3A and 3B are located on both sides of the clutch body 40 in the axial direction, and the first hydraulic pack 3A has the same construction as that of the prior art shown in FIG. By supplying the pressure oil, the piston 49 is pushed against the return spring 50, the friction plate 51 and the clutch plate 52 are pressed to enter the clutch state, and the supply of the pressure oil to the oil chamber 48 is stopped to return the piston 49. The spring 50 returns the piston 49 to the clutch disengaged state,
The electromagnetic switching valve 53 is also turned on to supply the pressure oil from the pump P to the first hydraulic pack 3A, and turned off to drain the oil.

On the other hand, in the second hydraulic pack 3B, as shown in FIG. 1, the piston 60 has an internal gear-like meshing portion 61.
The second gear has an external gear-like engaged portion 62, and a return spring 63 is arranged between the clutch body 40 and the outer circumference of the piston 60. This second
The hydraulic pack 3B pushes the piston 60 against the return spring 63 by supplying the pressure oil to the oil chamber 48 to disengage the meshing portion 61 from the meshed portion 62, and the oil chamber 48
When the oil is drained from the piston 60, the piston 60 is pushed back by the urging force of the return spring 63, the meshing portion 61 meshes with the meshed portion 62 and enters the clutch state, and the clutch body 40 and the second gear 42 are connected so as to rotate integrally. To do.

Electromagnetic switching valve 53 of the second hydraulic pack 3B
Is the same as that of the first hydraulic pack 3A, but when turned on, the pressure oil from the pump P is supplied to the oil chamber 48 to bring the clutch into a disengaged state, and when turned off, the oil chamber 48 is turned off.
Drain oil from the clutch and put it in the clutch. Then, when the engine E is stopped and the pump P is stopped, the supply of pressure oil is stopped and the second hydraulic pack 3B is put into a clutched state.

Both of the electromagnetic switching valves 53 are operated by the operating means for the front wheel drive / double speed switching mechanism 27, but in conjunction with the operating means for the rear wheel parking brake mechanism 5, When the wheel parking brake mechanism 5 is operated, the electromagnetic switching valve 53 can be set to be turned off. With such a configuration, when the rear-wheel parking brake mechanism 5 is operated by operating the rear-wheel parking brake operating means by turning off the engine E or without turning off the engine E, the front-wheel transmission system also rotates. You will be locked.

The present invention is not limited to the above embodiment, but can be variously modified. For example, the second hydraulic pack 3B of the hydraulic clutch 3 may be arranged on the double speed side of the front wheels, and the first and second hydraulic packs 3A and 3B may be switchable by a single switching valve. The hydraulic clutch 3 may be configured to only connect and disconnect the shafts 38 and 39, and the present invention may be applied thereto.

[0022]

According to the present invention described in detail above, the hydraulic clutch 3 has the meshing portion 61 formed on the piston 60, and the transmission shaft 3
The engaged portion 62 that engages with the engaging portion 61 when the piston 60 is pushed back to the 9 side by the return spring 63.
Therefore, when the engine E is stopped and the rear wheel parking brake mechanism 5 is operated, the hydraulic clutch 3 is engaged, and when the rear wheel is braked, not only the rear wheel but also the front wheel can be locked. By locking the front and rear wheels at the same time, even when a heavy work machine is mounted on the front part of the vehicle for slope parking, it is possible to park the vehicle more reliably than when locking only the rear wheels.

[Brief description of drawings]

FIG. 1 is an explanatory cross-sectional view of a main part showing an embodiment of the present invention.

FIG. 2 is an overall schematic diagram of a tractor mission.

FIG. 3 is a cross-sectional view showing a conventional technique.

[Explanation of symbols]

 2 hydraulic clutch 3 hydraulic clutch 4 rotary shaft 5 rear wheel parking brake mechanism 27 front wheel drive / double speed switching mechanism 38 first transmission shaft 39 second transmission shaft 40 clutch body 48 oil chamber 53 electromagnetic switching valve 60 piston 61 meshing portion 62 engaged Part 63 Return spring

Claims (1)

[Claims] 1. A branch from a rear-wheel transmission system having a hydraulic clutch (2) so that power can be freely connected to and disconnected from a transmission shaft (39) which is always interlocked with a front wheel via the hydraulic clutch (3). A rear wheel parking brake mechanism (5) is formed on a rotating shaft (4) that forms a front wheel transmission system for transmission and is always interlocked with the rear wheel.
And the hydraulic clutch (3) is provided with an oil chamber (48).
In a parking brake device for a traveling vehicle, in which the piston (60) can be pushed against the return spring (63) by supplying pressure oil to the hydraulic brake (3), the hydraulic clutch (3) is engaged with the piston (60) at a meshing portion ( 61) is formed, and the piston (6) is formed on the transmission shaft (39) side.
0) is pushed back by the return spring (63) to form a meshed portion (62) that meshes with the meshing portion (61).