JPH06257647A - Differential gear lock device - Google Patents

Abstract

PURPOSE:To provide a hydraulic differential gear lock device allowing easy assembly and maintenance without impairing responsiveness. CONSTITUTION:This differential gear lock device 11 has a shift fork 16 on a shift rod 15, and locks a differential gear device 2 via the axial shift of a differential gear lock shifter 14 where the shift fork 16 comes to be. engaged. In addition, the boss section 17 of the shift rod 15 or the shift fork 16 is provided with a hydraulic actuator 20 for shifting the shifter 14 in a locking direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diff lock device.

[0002]

2. Description of the Related Art When a tractor turns, the trajectories of inner and outer wheels are different, and even if the rotational speeds of the left and right wheels are different, the driving force must be transmitted equally. Therefore, a diff device is adopted. ing. On the other hand, the resistance of the tractor to the left and right wheels may differ depending on the soil conditions and the state of work even when the tractor is straight ahead, and when the differential device is operated, the straightness is inferior or the traction force is reduced.

Therefore, a diff lock device for stopping the operation of the diff device is adopted, and the diff lock device is classified into a mechanical type and a hydraulic type (new edition agricultural machine handbook No. 2).
See pages 84-285).

[0004]

Compared to the mechanical type, the hydraulic type has a good responsiveness since the valve (solenoid valve) is turned on / off to switch the hydraulic pressure when the pedal is operated, and the pedal is kept depressed. It is used for large tractors because it has the advantages that it does not need to be kept and the operator is less tired.

However, in the conventional hydraulic type, since the piston and the cylinder are built in the differential case, the assembly is very troublesome and the maintenance is difficult. Therefore, an object of the present invention is to facilitate the assembling and maintenance of the hydraulic differential lock without impairing its advantages.

[0006]

According to the present invention, a shift fork 16 is provided on a shift rod 15, and a diff lock shifter 14 with which the shift fork 16 engages is axially moved to lock the diff device 2. In order to achieve the above-mentioned object in the device 11, the following technical measures are taken.

That is, according to the present invention, the hydraulic actuator 20 for moving the differential lock shifter 14 in the locking direction.
The shift rod 15 and / or the shift fork 16
It is characterized in that it is provided in the boss portion 17 of.

[0008]

According to the present invention, when the hydraulic pressure is sent to the hydraulic actuator 20 via the solenoid valve by depressing a pedal or the like (not shown), the diff lock shifter 14 is moved through the shift fork 16.
Is operated in the locking direction to lock the differential device 2. Since the hydraulic actuator 20 is provided on the boss portion 17 of the shift rod 15 / or the shift fork 16,
Assembling and maintenance of the differential case 4 is easier than that of the built-in differential case 4.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described in detail below with reference to the drawings. In FIG. 1 illustrated for a rear wheel of a tractor, a four-pinion type is used in a mission case 1 which also serves as a tractor vehicle body. The diff device 2 is built in. The differential device 2 has pinion gears 6 at both ends of a pinion shaft 5 crossing each other in a diff case 4 having a large differential gear (crown gear) 3, and a pair of left and right differential side gears 7 meshing with the pinion gear 6. A brake shaft 8 as a differential output shaft is connected to each of the differential side gears 7 by a spline or the like.

A differential input shaft (not shown) is engaged with the large differential gear 3, the differential device 2 is rotatably supported by the transmission case 1 via a pair of left and right bearing cases 9, and a brake shaft 8 is provided. Is equipped with a brake device 10 and is connected to the rear wheels via a speed reducer (not shown). That is, when the left and right wheels have the same resistance, the differential device 2 rotates together with the differential case 4 while the six gears 6 and 7 of the differential case 4 are in mesh with each other.

On the other hand, if the resistance of the inner wheels increases during turning, and a difference in force occurs at the meshing point between the gears 6 and 7 in the differential case 4, the diff pinion gear 6 rotates, and as a result, the outer axle shaft is rotated. The number of rotations is increased to ensure a smooth turn. In this diff device 2, the resistance of the left and right wheels may differ depending on the soil conditions and the working conditions even when the tractor goes straight, and if the diff action works as described above, the straight running property and traction force decrease.

Therefore, the differential lock device 11 is provided. In the embodiment shown in FIG. 1, a lock hole 12 is formed on the rear surface of one of the differential side gears 7, and a differential lock shifter 14 having a lock pin 13 which can be engaged with and disengaged from the lock hole 12 is axially provided on a boss portion of the differential case 4. It is fitted so that it can move freely. Shift rod 15 in mission case 1
The boss portion 17 of the shift fork 16 is slidably fitted onto the shift rod 15, and the forked portion 16A of the shift fork 16 is engaged with the circumferential groove of the shifter 14. .

On the left and right of the boss portion 17 of the shift fork 16, cylinders 18 and 19 are axially immovably mounted on the shift rod 15, and a hydraulic actuator 20 is formed therein. By depressing the outer differential lock pedal to turn on / off the solenoid valve, the hydraulic pressure can be switched between the differential pressure direction hydraulic oil portion 20A and the unlock direction pressure hydraulic portion 20B.

Therefore, when hydraulic pressure is applied to the pressure oil portion 20A, the shift fork 16 slides in the L direction shown by the arrow using the shift rod 15 as a guide, and moves the shifter 14 in the same direction against the return spring 21. The lock pin 13 to the lock hole 1
Insert in 2 and diff lock. On the other hand, when hydraulic pressure is applied to the pressure oil portion 20B, the pressure oil portion 20B moves in the opposite L direction to release the diff lock.

The differential lock state is the switch S1.
Then, the release of the diff lock is detected by the switch S2, and the buzzer
An alarm device such as a lamp is operated, and the shift rod 15 is restrained from moving in the axial direction by screwing a screw plug 22 into an insertion hole 1A formed in the mission case 1. Therefore, the assembly and maintenance of the hydraulic actuator 20 can be easily performed through the insertion hole 1A, the upper opening 1B of the transmission case 1, and the like.

FIG. 2 shows an embodiment applied to a front wheel diff device. The diff device is a two-pinion type, and the fact that the diff device is built in a cylindrical front axle case 23 is the same as in FIG. Differences and common parts are indicated by common symbols, and the differences will be described below. The front axle case 23 is swingably suspended around the front center pin 24 and the rear center pin 25,
The rear center pin 25 is substantially a differential drive pinion shaft.

A locked dog 26 is formed on the end surface of the boss portion of the differential case 4, and a dog that engages with and disengages from the locked dog 26 is attached to the end surface of the cylindrical shifter 14 inserted in the differential support cylinder 27. 27 is formed. The hydraulic actuator 20 is assembled in the carrier 28 so as to be freely assembled and disassembled, and the forked portion 16A of the shift fork 16 is provided with the shifter 1
4 is engaged with the end surface.

The brake shaft shown in FIG. 1 serves as a pair of left and right differential output shafts, and is connected to the front wheels via final reduction gears provided at the ends of the respective shafts. FIG. 3 shows a third embodiment of the present invention, in which a liquid feeding passage 29A for the hydraulic actuator 20 is provided.
The difference is that 29B is formed on the shift rod 14 and the friction disk 30 is used for the differential lock, and this third embodiment can be adopted for both the front and rear wheels.

FIG. 4 shows a fourth embodiment, and in FIG.
The hydraulic actuator 20 applies hydraulic pressure only in the locking direction, and employs a return spring 31 for releasing the diff lock. FIG. 5 shows a fifth embodiment, which is different from the first embodiment shown in FIG. 1 in that the dock 32 is used instead of the pin, and the pressure oil portion 20B is a return spring 33.

FIG. 6 shows a sixth embodiment, which is different from the fifth embodiment in FIG. 5 in that the passage 34 for the pressure oil portion 20A is formed in the axial direction of the shift rod 14. FIG. 7 shows a seventh embodiment, in which the passage 3 for the pressure oil portions 20A and 20B is provided.
5A and 35B are formed in the axial direction of the shift rod 14,
The shifter 14 is formed with a dog 36, and the others are common to the above-described embodiments.

FIG. 8 shows an eighth embodiment in which the boss portion of the shift fork 16 is fixed to the shift rod 14, and the lock and unlock hydraulic actuators 20 are provided at both shaft ends of the shift rod 14. Is. That is, the shift rod 14 is slidably installed on the mission case 1, and both shaft ends of the shift rod 14 are used as piston portions. Therefore, the cylinder portions 37A and 37B are formed on both side walls of the mission case 1.

FIG. 9 shows the ninth embodiment, and in the previously described eighth embodiment, the differential lock is released not by the hydraulic pressure but by the return spring 3
It was set to 8. As described above, the first to ninth embodiments can be combined with each other. In any of the embodiments, the hydraulic actuator 20 is so-called externally mounted on the differential device so that the assembling, maintenance and the like are easy. Are common in that

[0023]

As described above in detail, according to the present invention,
Assembling maintenance and the like can be easily and easily performed without impairing the advantages of the hydraulic diff lock device such as good responsiveness and little operator fatigue. Therefore,
The present invention is useful when applied to a tractor.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a first embodiment of the present invention.

FIG. 2 is a plan sectional view showing a second embodiment of the present invention.

FIG. 3 is a vertical sectional view showing a third embodiment of the present invention.

FIG. 4 is a vertical sectional view showing a fourth embodiment of the present invention.

FIG. 5 is a vertical sectional view showing a fifth embodiment of the present invention.

FIG. 6 is a vertical sectional view showing a sixth embodiment of the present invention.

FIG. 7 is a vertical sectional view showing a seventh embodiment of the present invention.

FIG. 8 is a vertical sectional view showing an eighth embodiment of the present invention.

FIG. 9 is a vertical sectional view showing a ninth embodiment of the present invention.

[Explanation of symbols]

 2 diff device 14 diff lock shifter 15 shift rod 16 shift fork 20 hydraulic actuator

Claims (1)

[Claims] 1. A shift fork (16) is provided on a shift rod (15), and a differential lock shifter (14) engaged with the shift fork (16) is moved in the axial direction to lock the differential device (2). In the diff lock device (11), a hydraulic actuator (20) for moving the diff lock shifter (14) in the lock direction is provided with the shift rod (1).
5) / or the boss part (17) of the shift fork (16)
A diff lock device that is equipped with.