JPH0244611Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an improvement of a power steering device used in, for example, agricultural tractors.

(Prior art) Conventionally, as shown in Japanese Utility Model Application Publication No. 1987-1987,
A drive shaft that is rotated in conjunction with the rotation of the handle is provided on the outside of the tractor body in a forward protruding manner, and is provided on the front end of the drive shaft in the front-rear direction along the outside of the vehicle body. The rear end of the joint shaft was interlockingly connected via a universal joint, and the front end of the joint shaft was interlockingly connected via a universal joint to a valve operating shaft of a power steering body provided at the center of the front part. . In order to absorb minute axial movements (approximately 2 mm) caused by rotation of the valve operating shaft, the valve operating shaft and the yoke of the universal joint are spline-coupled to allow relative movement in the axial direction.

(Problems to be solved by the invention) According to the above conventional structure, the front end of the joint shaft and the valve operating shaft are arranged at a certain angle, and the universal joint that interlocks and connects them is bent. As a result, it is difficult to achieve smooth relative movement in the axial direction at the spline joint between the valve operating shaft and the yoke of the universal joint. Particularly, when the spline joints were moved in the direction of fitting into each other, the resistance was large. Therefore, when operating the steering wheel, there is a drawback that, for example, it is harder to turn the steering wheel to the left than to turn the steering wheel to the right. SUMMARY OF THE INVENTION In view of the above-mentioned problems, it is an object of the present invention to smoothly absorb minute movements in the axial direction accompanying the rotation of a valve operating shaft, thereby enabling smooth handle operation.

(Means for solving the problem) The technical means is that a drive shaft 21, which is rotated in conjunction with the rotation operation of the handle 15, is provided in a forward protruding shape on the side of the vehicle. The rear end of a joint shaft 22 provided in the longitudinal direction along the side of the vehicle is interlocked and connected to the front end of the joint shaft 21 via a universal joint 23, and the power steering body is provided at the center of the front of the vehicle. In the power steering device, the front end of the joint shaft 22 is interlocked and connected to the valve operation shaft 24 of No. 8 through a universal joint 25, in which the front end of the drive shaft 21 and the yoke 32 of the universal joint 23 are connected to the valve operating shaft 24 of the drive shaft 21. A biasing spring 33 that biases the yoke 32 forward is connected to the drive shaft 21 by a spline connection that is relatively movable in the axial direction.
is at the point extrapolated to .

(Function) According to the present invention, the drive shaft 2 at the side of the vehicle
The front end of the drive shaft 21 and the rear end of the joint shaft 22 are interlocked and connected by a universal joint 23, and the front end of the drive shaft 21 and a yoke 32 of the universal joint 23 are spline-coupled so as to be relatively movable in the axial direction of the drive shaft 21. Since the joint shaft 22 and the drive shaft 21, which are provided in the front-rear direction along the side of the vehicle, are arranged in parallel, the relative movement at the spline joint is performed smoothly. When operating the steering wheel, it can be operated smoothly regardless of whether the steering wheel is turned to the right or to the left. Furthermore, since the yoke 32 of the universal joint 23 is urged in the pulling direction by the urging spring, a good spline connection condition is always obtained, and the handle can be operated more smoothly.

(Example) Hereinafter, an example of the present invention will be described based on the drawings. In Figures 1 to 4, 1 is a tractor body, and an engine 2, a clutch housing 3, a transmission case 4, etc. are included as a structure. Front wheels 7, which are steering wheels, are supported at the front of the tractor body 1 via a front axle frame 5, a front axle case 6, etc., and each front wheel 7 is supported by a power steering wheel mounted on the front axle frame 5. Steering operation is enabled by lateral movement of the tie rod 9 of the main body 8.

10 is a rear wheel, 11 is a rear wheel fender, 12 is a hydraulic system for lifting and lowering the working machine, and 13 is a bonnet that covers the engine 2 and the like.

Reference numeral 14 denotes a driver's seat, which is provided so as to be changeable between a position above the hydraulic system 12 and a position above the rear of the bonnet 13. A handle 15 is fixed to the upper end of a handle shaft 16, and the handle shaft 16 is rotatably inserted into a handle post 17. 18
is a front mounting portion for mounting the handle 15 in a forward facing state, and is provided on the upper surface of the clutch housing 3. Reference numeral 19 denotes a rear attachment portion for attaching the handle 15 in a rearward position, which is attached to the side surface of the hydraulic device 12, and the handle post 17, handle shaft 16, etc. can also be attached to this rear attachment portion 19. Reference numeral 20 denotes a relay gear box, which is installed so as to close an opening formed at the lower part of one side of the clutch housing 3. This relay box 20 has a built-in bevel gear mechanism, and a drive shaft 21 in the front and rear direction.
is rotatably supported via a bearing. That is, the drive shaft 21 is pivotally supported on the outer side of the vehicle body 1. A joint shaft 22 is provided along the outer side of the vehicle body 1 in the front-rear direction, and its rear end is interlockingly connected to the front end of the drive shaft 21 via a universal joint 23. Further, the front end of the joint shaft 22 is connected to the rear end of a valve operating shaft 24 that switches the valves of the power steering body 8.
They are interlocked and connected via 5. The front and rear ends of the joint shaft 22 have respective universal joints 23,
25 yokes 26, 27 are integrally fixed. A spline portion 28 is formed at the protruding end of the valve operating shaft 24, and a yoke 29 of the universal joint 25 is spline-coupled to the spline portion 28 and fixed with a bolt 30 so as not to come off. A spline portion 31 is formed at the forwardly projecting end of the drive shaft 21, and a yoke 32 of the universal joint 23 is spline-coupled to the spline portion 31. The spline joint portion allows the yoke 32 to move relative to the drive shaft 21 in the axial direction. Further, between the relay gearbox 20 and the yoke 32, a biasing spring 33 made of a coil spring is provided in a manner that is inserted over the drive shaft 21, and biases the yoke 32 forward, that is, in the withdrawal direction.

The drive shaft 21 is extended rearward, and its rear end is rotatably held by a bearing 34 fixed to the transmission case 4.
It is interlocked and connected to a connecting shaft via a rotational interlocking system consisting of two universal joints 35 and 36 and a joint shaft 37. The joint shaft 37 is the transmission case 4
It is rotatably held by a bearing fitting provided as appropriate. Reference numeral 38 denotes an interlocking shaft, which is disposed diagonally through the opening of the clutch housing 3 on one side of the deceleration case and downwardly downward.
The upper end is supported by a connecting shaft via a universal joint 39, the lower end is supported by a relay gear box 20 via a bearing, and is interlockingly connected to a drive shaft 21 via a bevel gear mechanism within the box 20.

40 is a step, and the drive shaft 21 and the like are arranged below this step 40.

The embodiment of the present invention is constructed as described above, and when the handle 15 is rotated, the handle shaft 16, the connecting shaft, the universal joint 39, the interlocking shaft 38, the bevel gear mechanism, the drive shaft 21, the universal joint 23, The valve operation shaft 24 of the power steering main body 8 can be rotated in forward and reverse directions via the joint shaft 22 and the universal joint 25, and the front wheels 7 can be steered. As the valve operating shaft 24 rotates forward and backward, the valve operating shaft 24 makes a minute movement in the axial direction, but this minute movement is caused by the spline portion of the drive shaft 21
1 and the yoke 32 of the universal joint 23 by relative movement of the spline joint. At this time, the drive shaft 21 and the joint shaft 22 are connected to the vehicle body 1.
Since they are disposed parallel to each other in the front-rear direction on the outer side of the spline joint, relative movement at the spline joint is performed smoothly. Therefore, there is less load when rotating the handle 15, and the handle 15 can be operated smoothly regardless of whether the steering wheel is turned to the right or to the left. In addition, since the yoke 32 of the universal joint 23 is biased forward, that is, in the direction of removal, by the biasing spring 33, the spline joint is not inserted more than necessary, and a good spline joint state can always be obtained. 15 operations can be performed more smoothly. Furthermore, the biasing force of the biasing spring 33 can prevent rattling in the spline joint.

In the above embodiments, a forward/reverse type tractor is shown, but a normal tractor may be used.

(Effect of the invention) According to the invention, the front end of the drive shaft on the side of the vehicle and the rear end of the joint shaft are interlocked and connected by the universal joint, and the front end of the drive shaft and the yoke of the universal joint are driven. The shafts are spline-coupled so as to be relatively movable in the axial direction of the shaft, and the joint shaft and the drive shaft, which are provided in the longitudinal direction along the side of the vehicle, are arranged in parallel. Relative movement is performed smoothly, and therefore, the steering wheel can be operated smoothly regardless of whether the steering wheel is turned to the right or to the left. Further, since the yoke of the universal joint is urged in the direction of removal by the urging spring, a good spline connection state can always be obtained, and there is an advantage that the handle can be operated more smoothly.

[Brief explanation of the drawing]

FIG. 1 is an enlarged sectional view of a main part showing an embodiment of the present invention, FIG. 2 is an overall side view, FIG. 3 is a plan view of the same part, and FIG. 4 is an explanatory diagram of a power steering device. 1... Tractor body, 8... Power steering body, 15... Handle, 21... Drive shaft, 2
2...Joint shaft, 23...Universal joint, 24...
... Valve operation shaft, 25 ... Universal joint, 32 ... Yoke, 33 ... Biasing spring.

Claims (1)

[Scope of utility model registration request] A drive shaft 21 that is rotated in conjunction with the rotation of the handle 15 is provided on the side of the vehicle in a forward protruding manner, and a drive shaft 21 is provided at the front end of the drive shaft 21 in the front-rear direction along the side of the vehicle. The rear end portion of the provided joint shaft 22 is interlocked and connected via a universal joint 23, and the joint shaft 22 is connected to a valve operating shaft 24 of a power steering body 8 provided at the front center of the vehicle.
In the power steering device, the front end of the drive shaft 2 is interlocked and connected via a universal joint 25.
1 and the yoke 32 of the universal joint 23 are spline-coupled so as to be relatively movable in the axial direction of the drive shaft 21, and a biasing spring 33 that biases the yoke 32 forward is attached to the drive shaft 21 externally. A power steering device characterized by being inserted.