JPH032116B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a four-wheel steering device suitable for a vehicle such as a riding work machine having a handle in the center of the vehicle body.

(Prior Art) Agricultural working machines such as tractors have a large steering angle, so the front wheels are smaller than the rear wheels.In order to improve running performance, the applicant has designed the front wheels to have approximately the same diameter as the rear wheels. The applicant proposed a device with a large diameter.

In such a configuration, if the steering angle of the front wheels is set large, there is a risk that the front wheels will interfere with the front side of the vehicle body, and therefore, setting the steering angle large is accompanied by difficulty. On the other hand, this type of working machine is required to have a small rotation semi-mechanism so that it can turn easily, so attempts have been made to steer the front and rear wheels in opposite phases to reduce the turning radius.

Conventional four-wheel steering mechanisms for this type of working machine include Utility Model Publication No. 29-4015 and Japanese Patent Publication No. 37-2362.

(Problems to be Solved by the Invention) Regarding the above-mentioned prior art, first of all, in Utility Model Publication No. 29-4015, a frame and a link mechanism are provided between the front wheels, and since the engine is disposed in this part, the link mechanism, etc. It is difficult to actually install it, and since it has to be installed under the engine, it is disadvantageous in terms of protecting the mechanism.
If you try to increase the distance from the road surface, the ground clearance will increase, and the mechanism will become more complicated due to the need for the engine. If a layout in which a transmission is disposed between the rear wheels is adopted, the rear wheel steering mechanism will be located below this, resulting in the same inconvenience as described above.

On the other hand, in Japanese Patent Publication No. 37-2362, the steering interlocking mechanism of the front and rear wheels is performed by intersecting links in an X-shape in plan view, but this requires two interlocking links, which increases the number of parts, and By arranging two links vertically and crossing them, it is necessary to bend or escape the intersection of the links so that they do not interfere.
This involves complicating the link structure, ensuring rigidity, and other inconveniences in implementation.

The present invention has been made to solve the above technical problems.

(Objective of the Invention) The object of the present invention is to provide a vehicle in which an engine is disposed between the front wheels and a transmission between the rear wheels, and a steering and interlocking mechanism is disposed between these without interfering with these. , ensuring smooth and sufficient movement of these mechanisms, ensuring a sufficient steering angle, realizing the above with a simple configuration, and arranging these mechanisms extremely advantageously in terms of space utilization. The purpose is to obtain a wheel steering device.

(Means for Solving the Problems) In order to solve the above problems and achieve the object, the present invention provides a vehicle in which an engine is disposed between the front wheels and a transmission is disposed between the rear wheels. To,
A pair of left and right front wheel steering tie rods extending in the vehicle width direction, and an arm that connects and supports the inner ends of both tie rods at the center of the vehicle width direction, and swings left and right in conjunction with steering operation of the steering wheel. On the other hand, a pair of left and right rear wheel steering tie rods extending approximately in the longitudinal direction is provided on the sides of the transmission, and the front and rear wheels are connected and supported between the front ends of the two tie rods at the center in the vehicle width direction. The present invention is characterized in that a swingable arm is disposed in front of the transmission, and this arm and the arm are connected by a link extending substantially in the front-rear direction.

(Effects of the above means) As described above, four-wheel steering is achieved, and the tie rod can move without interfering with the engine and transmission.

(Embodiment) Next, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

The embodiment will be explained using a riding work machine as an example, but
The present invention can be implemented in any vehicle in which the steering mechanism is located at the center in the width direction of the vehicle.

FIG. 4 is a perspective side view showing a main part of the riding work machine 1 in cross section, in which a frame 3 having a box-like cross section is provided in the lower part of the vehicle body 2 at the center in the vehicle width direction in the front and rear direction. The frame 3 consists of a front part 301 and an intermediate part 302 connected to the front part, and an engine 4 is mounted on the front part.
02 is arranged inclined to one side as shown in FIG. A crankshaft 403 disposed in a crankcase 401 of the engine 4 faces in the front-rear direction, and a flywheel 404 and a cooling fan are provided at the rear end of the crankshaft 403, and the output section 406 is connected rearward via a joint 407. The propulsion shaft 40 is connected to a first propulsion shaft 408 extending to
8 is disposed below the floor 201 of the vehicle body 2 and above the frame 3.

At the bottom of the front and rear of the vehicle body 2 are left and right front wheels 501, 5.
02, the left and right rear wheels 503, 504 are arranged, and in this embodiment, the crankshaft 4 facing forward and backward as described above is installed.
03 so that a part thereof faces within the trajectory A of the front wheels 501 and 502. The drive system for the wheels 501 to 504 is as follows.

A transmission 6 is disposed at the rear of the vehicle body 2, and the rear end of the first propulsion shaft 408 is connected to an input shaft 601 via a joint 409. A gear shift lever 605 is provided extending forward from the top of this, with the knob 604 facing above the floor 201. A reduction case 607 is installed hanging down from the rear left and right sides of the lower part 606 of the case 602, and left and right rear wheels 503, 504 are mounted on a rear axle 608 extending outward from the lower half of the case 602. The rear wheels 503, 504 are connected to each other and drive the rear wheels 503, 504.
The left and right reduction cases supporting 504 are pivoted to the frame side in the same manner as the front wheels described later, and can be steered left and right.

Transmission case 602 lower part 606
faces the rear of the frame 3, the output shaft 609 protrudes from the front of this part, and the joint 41 is attached to this.
0 to connect the rear end portion of the second propulsion shaft 411.
The second propulsion shaft 411 extends forward through a duct-like space 303 provided in the front-rear direction inside the frame 3, and connects the front end of the propulsion shaft 411 to the joint 41.
The transmission case 7 is connected to the input shaft 701 of the transmission case 7 through the frame 3, and the transmission case 7 is provided at the middle part in the longitudinal direction of the front part 301 of the frame 3 and the middle part in the vehicle width direction, and the front part 301 of the frame is shown in FIG. As shown, shallow channel-shaped members 304 and 305 are configured to face each other vertically, and the members 304 and 30
A transmission case 7 is disposed between 5 and 5.

Output shafts 702, 702 are provided on the left and right sides of the transmission case 7.
stands out, and the universal joint 70
Drive transmission shaft 7 extending left and right through 3,703
04, 704 are connected, and the shafts 704, 70
Connect the other end of 4 to the universal joint 705, 70
5 to the left and right reduction cases 706, 7.
06 input shafts 707, 707. Output shaft 70 of left and right reduction cases 706, 706
8,708 are connected to the front wheels 501, 502, and the reduction cases 706, 706 are connected to each transmission shaft 70.
4,704 are placed before and after this,
Arms 306 extending outward (left and right),
307...come in between. The arms 306, 307... have respective proximal ends of the links 8, 8 pivotally attached 801, and the links 8 extend outwardly, with the tips 802 connected to the king pin unit 803 of the reduction case 706.
This allows the front wheels 501, 502 to swing up and down, and the front wheels 501, 502 are pivoted around the upper and lower king pins 804, 805 of the unit 803 as fulcrums.
02 can swing left and right and performs steering and turning. The rear wheels 503, 504 are similarly suspended, and the left and right output shafts 610, 610 of the transmission 6 are connected to the left and right transmission shafts 612, 612 via a joint 611.
and connect the transmission shafts 612, 612 to the joint 6.
13 and 613 are connected to the input shaft 614 of each reduction case 607 to transmit power to the rear wheels 503 and 504.

Each of the reduction cases 706, 607 for the front wheels 501, 502 and the rear wheels 503, 504 has nutcle arms 51, 5 provided on the front, rear, left and right sides, respectively.
2, 53, and 54. The front wheel side knuckle arms 51, 52 are the rear parts 511, 52 of this
1 extends rearward in parallel, and the knurcle arm 51,
The rear portions 511, 521 of 52 are the tip portions 55 of tie rods 55, 56 extending inward in the vehicle width direction.
Pivotally connected to 1,561, tie rod 55,5
The tie rods 55 and 56 are provided in the vehicle width direction at the rear of the engine.
6. The base end portions 552, 562 facing the center of the vehicle body are pivotally connected to the left and right portions of the T-shaped front portion 571 of the center arm 57. The center arm 57 faces above the boundary between the middle part 302 and the front part 301 of the frame 3,
A steering gear box 58 is disposed on the arm 57. As shown in enlarged detail in FIGS. 2 and 3, the gearbox 58 has upper and lower halves 581,
As shown in FIGS. 1 and 2, a sector gear 59 is housed inside the sector gear 582, and a shaft 61 longitudinally connected to the base 591 of the gear 59 is connected to the outside and below the bottom of the lower half of the gear box 58. extended to
The extending end portion 611 is tied at the midpoint 572 of the arm 57. In front of the sector gear 59 is a toothed portion 59 of this.
A pinion 62 that meshes with the pinion 6 is installed vertically.
2 causes the shaft portion 621 to protrude above the upper half body 581,
This part is connected to the shaft 631 of the handle 63 disposed on the front part at the center part in the width direction of the floor 201, so as to rotate the rotary operation pinion 62 of the handle 63, and the shaft 631 is connected to the raised handle post 632. It hangs down through the inside.

The center arm 57 described above has a substantially L-shape with a large angle in plan view, and a rear portion 573 extending rearward and lateral behind the pin 61 is pivotally connected to the distal end portion 641 of the connecting link 64 . On the rear of the frame 3 is a support pin 6.
A pin 65 is provided at the center in the vehicle width direction in front of the transmission 6, and a center point 661 of a V-shaped rear center arm 66 in plan view is pivotally supported on this. In addition, the lengths of the arms 662 and 663 extending anterolaterally are unequal, and the tip of the long arm portion 662 and the rear end portion 6 of the link 64 described above
42 are pivotally connected, and the link 64 is disposed diagonally in the middle part of the vehicle body in the front-rear direction, with its tip facing toward one side and its rear end facing toward the other end, as shown in FIG. Then, the inner tip of the longer arm 662 and the tip of the other short arm 663 are pivotally connected to the tips 671, 672 of the left and right pair of tie rods 67, 68, and the pin 65 connects the rod 67. , 68 are of equal length, and the left and right tie rods 67, 68 are extended rearward so that their respective rear ends 672, 682 face outward, and the rear ends 672, 682 are connected to the rear wheel side. Each tip 5 of the left and right knuckle arms 53, 54
31, 541, and tie rods 67,
Numerals 68 are provided in a V-shape in plan view so as to be sequentially spaced apart from each other in a plan view, and pass on both sides of the transmission 6, which is the transmission.
1,541 faces Mission 6. This forms a steering mechanism 50, which is disposed on the frame 3 by utilizing the space between the upper and lower propulsion shafts 408, 411.

In this way, all four wheels 501 to 504 on the front, rear, left and right sides are driven, and the four wheels 501 to 504 are steered. Specifically, the engine power output by the propulsion shaft 408 is shifted in transmission by the transmission 6, and then transferred to the drive system 6.
Reduction case 60 via 10-614
7,607, which drives the rear wheels 503, 504, and is also input to the front transmission case 7 via the propulsion shaft 411, and its output is sent to the reduction case via the left and right drive systems 702 to 707. 7
06,706 and drives the front wheels 501,502. Four-wheel drive is achieved in this manner.

On the other hand, when the steering wheel 63 is rotated to the right or left, the pinion 62 is rotated to the right or left.
As a result, for example, the center arm 57 is swung counterclockwise in FIG.
1,512 to the left, and the king pin 80
The front wheels 501 and 502 are swung to the right using 4 and 805 as fulcrums, and the front wheels are steered. Also arm 57
Push the link 64 rearward by swinging in the same direction, swing the rear center arm 66 clockwise about the pin 65, push one tie rod 67,
Pull the other 68, push and pull the nutcle arms 53, 54, and move the left and right rear wheels 503, 504 to the front wheel 5.
01, 502 and is oscillatingly steered in the opposite phase. By steering the front wheels 501 and 502 in opposite phases in this way, the front wheels 501 and 502 are driven by wheels with approximately the same diameter as the rear wheels 503 and 504, and the steering angle of the front wheels 501 and 502 is small. The turning radius is also smaller than that of conventional small front wheels, and even though the large-diameter front wheels are used, they do not interfere with the front of the vehicle body.

In the above, the front tie rods 55 and 56 are arranged behind the engine 4, and are moved left and right by the gear box 58 in the center of the vehicle body and the center arm 57 in the center, so that the front tie rods 55 and 56 are pushed and pulled for left and right steering motion. When moving, the amount of tilt is small, so there is no interference with the engine, and the rear wheels are simultaneously steered in opposite phases, which improves the steering function of the front wheels and prevents interference with the engine and peripheral equipment. It can be avoided.

On the other hand, the rear tie rods 67 and 68 are arranged in a V-shape, pass on both sides of the transmission 6, and are pushed and pulled by the V-shaped rear center arm 66, so they move approximately in a straight line, and therefore move left and right. Since the amount of movement is small, interference with the transmission can be avoided.

In this way, the four-wheel steering function can be smoothly operated while avoiding interference with the engine and transmission.

By the way, a seat 9 is provided at the center in the vehicle width direction on the rear part of the vehicle body 2, and the seat 9 is provided at the same position behind the steering wheel 63, and there is only one occupant. Seat 9 is attached to base 1 above transmission 6.
0 via the substrate 901, and the base 10
A hitch 101 is swingably extended rearward at the lower rear portion of the rotor, and the hitch 101 is swung up and down via a link 102, and a rotor and other components are assembled to the hitch portion 103. Also, the upper member 30 of the frame front part 301
4. A base 11 is provided at the front part of the base 11, and a hitch 111 is provided at the lower part of the base so as to be swingable via a link 112. The hitch part 113 projects forward and is used to assemble rollers and the like.

In Fig. 1, 12 indicates a fuel tank, and 13 indicates a muffler. In the embodiment, a part of the crankshaft 403 faces within the trajectory A of the front wheels 501, 502, so the overall height of the engine 4 is low, and the front part of the vehicle body is The bonnet 202 provided at the front can be lowered so as to be tilted forward and downward.

(Effects of the Invention) As described above, according to the four-wheel steering device of the present invention,
without interfering with the engine located between the front wheels.
By swinging the arm that is located in the center of the rear of the engine and linked to the steering operation of the steering wheel, the front wheel steering tie rod can be moved from side to side in the vehicle width direction behind the engine, and the front wheels can be steered. The rear wheels can be steered approximately in the front-rear direction on the side of the transmission by swinging an arm installed in the front center of the transmission and connected to the arm via a link without interfering with the transmission installed in the transmission. The rear wheels can be steered by moving the tie rod back and forth, which reduces the vehicle's ground clearance and simplifies the mechanism by utilizing the space between the engine at the front of the vehicle and the transmission at the rear of the vehicle. A four-wheel steering mechanism can be installed while achieving this.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention; FIG. 1 is a plan view showing the power and steering mechanism for explaining a four-wheel steering system, FIG. 2 is an enlarged plan view of a gearbox, and FIG. 3 is an enlarged plan view of the same. 4 is an explanatory longitudinal side view of a riding work machine as an example of a vehicle; FIG. 5 is an explanatory longitudinal front view showing the front wheel side; and FIG. 6 is a front view for explaining the power transmission mechanism. 7 are plan views of the vehicle. In the drawing, 501 and 502 are the front wheels, and 503 and 50 are the front wheels.
4 is the rear wheel, 4 is the engine, 6 is the transmission, 55,
56, 67, and 68 are tie rods, 64 is a link, and 57, 59, 62, and 63 are steering mechanisms.

Claims (1)

[Scope of Claims] 1. A vehicle in which an engine is disposed between the front wheels and a transmission is disposed between the rear wheels, comprising: a pair of left and right front wheel steering tie rods extending in the vehicle width direction behind the engine; An arm is provided that connects and supports the inner ends of the tie rod at the center in the vehicle width direction, and swings left and right in conjunction with the steering operation of the steering wheel, while an arm that swings left and right in conjunction with the steering operation of the steering wheel is provided on the side of the transmission. A pair of left and right rear wheel steering tie rods extending from one side to the other is disposed, and an arm capable of swinging back and forth is disposed in front of the transmission to connect and support the front end portions of the two tie rods at a central portion in the width direction of the vehicle. Also, a four-wheel steering system for a vehicle, in which this arm and the arm are connected by a link extending substantially in the longitudinal direction.