JPH0613299B2 - Power steering device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a power steering device, and is used, for example, in a traveling vehicle such as an agricultural tractor.

(Prior Art) A power steering device for a tractor slidably supports an axle through a center shaft on an axle frame, and steerably attaches steering wheels to both ends of the axle through king pins.
A cylinder tube of a power cylinder was attached to an axle in parallel with this, and a piston rod of this power cylinder was connected to a steering arm by a tie rod having a pair of joints.

(Problems to be Solved by the Invention) However, in the conventional technology, the tie rod is connected to the most advanced piston rod of the power cylinder, and since the left and right end distances of the piston rod are long, the tie rod is short and the tread When adjusting, the adjustment distance cannot be lengthened.

This is because the tube of the power cylinder is fixed to the axle and the steering arm rotates, so that it must be connected by a tie rod having a joint in order to absorb them.

This causes problems such as difficulty in narrowing the tread and loss of steering force transmission to the steering arm.For example, in a narrow tractor such as a vineyard, the cutting angle is reduced. It is disadvantageous because the (operation angle) is large and the tread cannot be narrowed.

An object of the present invention is to solve the above-mentioned problems by mounting a tube of a power cylinder on an axle so as to be rotatable in the front-rear direction.

(Means for Solving the Problems) According to the present invention, an axle 12 is slidably supported on an axle frame 7 via an axle 23, and steerable steering wheels 2 are supported on both ends of the axle 12. In the power cylinder 26 for steering the steered wheels 2 mounted substantially parallel to the axis of the axle 12, the following technical means are taken to achieve the stated purpose.

That is, the present invention is the support member 33 fixed to the axle 12.
, A cylinder tube 27 of the power cylinder 26 is pivotally supported by a support shaft 35 in the axial direction of the axle so as to be slidable forward and backward, and a steering wheel 2 is fitted on the axis of piston rods 28 and 29 fitted into the cylinder tube 27. It is characterized by being linked to the side.

(Operation) When the hydraulic pressure is supplied to the cylinder tube 27 of the power cylinder 26 from the control unit (valve) which is switched by the operation of the steering handle 4, the piston rods 28 and 29 are slid to steer the steering arm 20. The force is transmitted, and each steering arm 20 is rotated in the direction of arrow B in FIG. 2 to steer the steering wheels 2, 2.

The movement of the steering arm 20 makes an arcuate movement B, and accordingly, the left and right and front and rear movements must be allowed, but the cylinder tube 27 is centered on the support shaft 35 and is in the front and rear direction in the direction of arrow A in FIG. Since it swings to the left and right, it can be steered without being twisted while allowing forward and backward and up and down movements.

Further, as a result, the force of the piston rods 28, 29 in the axial direction acts directly on the steering wheel 2 via the steering arm 20 to transmit power without loss.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

In FIG. 7, 1 is a tractor, a pair of left and right front wheels 2,
It is a two-axis, four-wheel type having a pair of left and right rear wheels 3 and front wheels.
2 is the steering wheel.

In FIG. 7, reference numeral 4 denotes a steering wheel, which operates the control valve of the all-hydraulic power steering. The bonnet 5 covers the engine 6 and its trap.

1 to 4, reference numeral 7 denotes an axle frame, which is made of, for example, cast metal and has a saddle shape in a side view, has a mounting hole 8 for a bumper or the like on its front end elevation surface, and has a tractor on its rear end elevation surface. It has a mounting hole 9 for the machine body 1A.

10 is a center bearing front bracket, 11 is also a rear bracket, and bolts 10A and 11A are attached to the front and rear lower surfaces of the axle frame 7.
Is detachably attached.

12 is an axle, and in this embodiment, a diff mechanism is provided in the central case 13.
A front wheel drive type that has 14 and has cylindrical cases 15 on the left and right of the central case 13 and encloses the differential output shaft 16.

An electric case 17 with a built-in transmission mechanism linked to the differential output shaft 16 is attached to each outer end of the left and right tubular cases 15,
A front wheel case 19 is steerably supported on each electric case 17 via a kingpin 18. A steering arm 20 is provided on the front wheel case 19 and a front wheel (steering wheel) 2 is supported as a drive type. Has been done.

Reference numeral 21 is a propulsion shaft device, which is interlocked and connected to the transmission system of the rear wheel 3,
It is interlocked with the differential mechanism 14 via the differential drive shaft 22 on the rear bracket 11 side.

Reference numeral 23 denotes a center shaft, which is projected from the central case 13 on the extension line of the differential drive shaft 22 and is rotatably supported by the bearing cylinder 24 via the front bracket 10. Here, the axle 12 has the center shaft 23. It is slidably supported by the axle frame 7 via. The differential drive shaft 22 also functions as a so-called center shaft, and 25 indicates a differential case lid.

A power cylinder 26 for steering includes a cylinder tube 27, a double action type piston fitted to the cylinder tube 27, and a pair of left and right piston rods 28 and 29 connected to the piston.

Reference numeral 30 denotes a power cylinder accommodating chamber, which is formed on the front side of the central case 19 so as to penetrate in the left-right direction through a partition wall 31. Inside the accommodating chamber 30, the cylinder tube 27 has its axis centered on the axle.
It is housed approximately parallel to the 12 axes.

A mounting boss 32 is formed on the upper wall of the central case 19 so as to project therefrom.
The support member 33 is fixed to the axle 12 and extends in the front horizontal direction.

Reference numeral 35 denotes a support shaft, which has at least a rotating shaft center in the axial direction of the axle and pivotally supports the support member 33 and the cylinder tube 27 so as to be capable of swinging back and forth relatively, as shown in FIG. In the first embodiment, a female screw boss 27A is provided on the cylinder tube 27 on the vertical plane of the center shaft 23, a male screw portion 36 having a ball receiver is screwed into the female screw boss 27A, and a screw shaft 37 having a ball 37A is attached to the support member 33. It is exemplified as a universal joint structure in which a taper is inserted and fastened with a nut 38.

Therefore, an insertion window 30A is formed on the top wall of the accommodation chamber 30, and a fastening / loosening window 7A for the nut 38 is opened in the center of the upper ceiling wall of the axle frame 7.

Piston rods 28 and 29 extending outward in the left-right direction from the cylinder tube 27 have a male screw 28A as shown in FIG. 5, one of which is screwed onto a female screw 39A of a turnbuckle 39 to lock nut 40. Stop with the operation arm
Male thread 42 of tie rod 42 connected to 20 via pivot 41
A is screwed into the female screw 38B of the turnbuckle 39 and is fixed with a lock nut 43.There is an axis center of the tie rod 42, etc. on the extension line of the axis center of the piston rods 28, 29, and there is a steering arm. It is linked to the steering wheel 2 side via 20.

The female screws 39A and 39B of the turnbuckle 39 have opposite screw directions, and the toe-in adjustment of the steering wheel 2 is possible by loosening and extending the lock nuts 40 and 43.

In addition, 44 is a battery, which is closed to the window 7A and a battery mount 46 is attached to the top wall of the axle frame 7 with a bolt (not shown) through a cushion sheet (rubber plate) 45.
The battery 44 is stored in and is fixed by the bracing rod 47.

Reference numeral 48 is an air cleaner, and a support 43 is erected on the top wall of the axle frame 7 and is supported by the support 49. 50 is a radiator.

51 is a bonnet mounting seat, which has a bolt hole 51A in the seat 51 on the front surface of the axle frame 7, and the front side of the bonnet is supported by bolts screwed into the bolt hole 51A. A bent piece 5A at the lower end of the bonnet is fixed to a mounting seat 51 of the hood through a cushion sheet (rubber plate) 52 with a bolt 53 to prevent dust and the like from entering there.

FIG. 6 shows a second embodiment of the present invention, in which the support member 33 is formed into a bifurcated shape, and the support shaft 35 is inserted into the bifurcated portion 33A through an arm 27B protruding from the cylinder tube 27. Others are common to FIG. 1, and common parts are denoted by common reference numerals. The arm may be a screw structure and extendable.

In the above configuration, when hydraulic pressure is applied to the tube 27 of the power cylinder 26, the piston slides to the left or right, and in this example, one of the piston rods 28 and 29 presses the steering arm 20 and the other one. Then, the steering arm 20 is retracted, and the steering wheel 2 is steered at a predetermined turning angle.

In this steering, when the swing arm 20 swings in the direction of arrow B, the front and rear of FIGS. 1 and 6 centering on the pivot shaft 41 and the support shaft 35 of the piston rods 28 and 29 with respect to the steering arm 20. The power cylinder 26 is not twisted by the correction and absorption by the swing of the cylinder tube 27 in the direction A.

Further, the toe-in adjustment is made by fastening and loosening the lock nuts 40 and 43.

(Advantages of the Invention) The present invention is as described above, and a cylinder tube of a power cylinder is pivotally supported on a support member fixed to an axle so as to be swingable back and forth via a support shaft in the axial direction of the axle. Since it is characterized in that the inserted piston rod is interlockingly connected to the steering wheel side on the axial center line, it has the following advantages.

The stroke of the piston rod can be increased,
As a result, the power is sufficient even if the diameter of the cylinder tube is reduced, so that the cylinder tube can be mounted even in a narrow space.

The movement of the steering wheel due to steering can be followed by the movement of the cylinder tube around the support shaft in the front-rear direction, and the twisting is small, and the power to the steering wheel can be transmitted directly and surely without loss.

Therefore, it is useful when applied to the case where the steering wheel has a large cutting angle and the tread is narrowed.

[Brief description of drawings]

The drawings show an embodiment of the present invention. Fig. 1 is a side sectional view, Fig. 2 is a front (normal) view, Fig. 3 is a flat front view, and Fig. 4 is a rear (rear) view, Fig. 5 Is a sectional view of the buckle, and FIG.
FIG. 7 is a side sectional view of the embodiment, and FIG. 7 is a plan view of the tractor. 1 ... tractor, 2 ... steering wheel, 7 ... axle frame,
12 …… Axle, 20 …… Steering arm, 26 …… Power cylinder, 27 …… Cylinder tube, 28 …… Piston rod,
35 ... A spindle.

Claims (1)

[Claims] Claims: 1. An axle 12 is slidably supported on an axle frame 7 via a center shaft 23, and steerable steerable wheels 2 are supported at both ends of the axle 12, and the steerable wheels 2 are steered. A power cylinder 26 for mounting the power cylinder 26 substantially parallel to the axis of the axle 12, the power cylinder 26 is attached to the support member 33 fixed to the axle 12.
Cylinder tube 27 is rotatably supported in the front and rear direction via a shaft 35 in the axial direction of the axle, and is linked to the steering wheel 2 side on the axis of piston rods 28 and 29 fitted in cylinder tube 27. A power steering device characterized in that