JPH0627465Y2 - Safety device for vehicle having steering wheel speed increasing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a vehicle safety device having a steering wheel speed increasing device.

(B) Conventional technology Conventionally, for example, in a four-wheel drive vehicle such as an agricultural tractor, when the turning wheel (front wheel) has a longer path length than the rear wheel due to an inner wheel difference when turning, etc. Since it is driven at high speed, there is a drawback that it is difficult to make a sharp turn, and in order to eliminate this drawback, a speed increasing device that can switch the speed ratio is interposed between the final drive device of the front wheels and the front propeller shaft. When the steering wheel is steered greatly, the speed ratio switching mechanism operates to automatically switch the speed increasing device to the speed increasing operation side, thereby eliminating the difficulty of a sharp turn due to the difference in the path length. It is known that the above method is used (see, for example, Japanese Patent Laid-Open No. 62-55226).

(C) Problems to be solved by the invention However, the speed ratio switching device is interlocked with the steering wheel, and if the steering wheel is steered greatly, the steered wheel speed increasing device is interlocked with the steering wheel. However, there is a drawback in that a sudden turn is performed by switching to the speed-up operation state, which causes a risk of overturning the body.

(D) Means for Solving the Problems In the present invention, there is provided a steering wheel speed increasing device capable of driving front and rear wheels and capable of switching a speed ratio between a final drive device for front wheels and a front propeller shaft. In a vehicle in which a speed ratio switching mechanism interveningly connected to a steering wheel is used to switch the speed increasing device from a constant speed operating state to a speed increasing operating state, a front axle case supporting front wheels is The tilt mechanism is pivoted so that it can be tilted to the left and right around the swing axis, and a detection mechanism that detects the relative tilt angle between the aircraft and the case is provided. When the steering wheel speed increasing device is connected, the steering wheel speed increasing device is configured to automatically maintain a constant speed operation state when the left and right tilt angles are larger than a preset angle. Does not provide a safety device for vehicles with It is what

(E) Action / Effect According to this invention, since the front axle case supporting the front wheels can be swung to the left and right, it is possible to detect the left and right inclination of the body by the relative inclination angle between the body and the front axle case. When this angle becomes larger than the preset angle, the constant speed operation state of the steering wheel speed increasing device is forcibly maintained to prevent sudden turning of the aircraft and ensure safety. can do.

In addition to the unevenness and inclination of the ground, the cause of the body tilt is that the center of gravity becomes high when a work machine is connected to the machine, especially when a front-mounted work machine is connected, and However, in the present invention, when the machine body tilts at a predetermined angle or more, the steered wheel speed increasing device immediately becomes a constant speed operation state, and a sudden turn is prevented to maintain safety.

(F) Embodiment An embodiment of the present invention will be described in detail with reference to the drawings. In FIG. 7, (A) shows a four-wheel drive tractor, which is powered by an engine section (1) provided at the front of the machine body. , The clutch housing (2) and the transmission case (3) to drive the left and right rear wheels (4) arranged on the left and right sides of the same case (3) to extend the front propeller extending in front of the transmission case (3). shaft
(5), left and right front wheels via final drive device (6)
The steering wheel (8) provided behind the engine unit (1) is used to drive the (7) and steer the left and right front wheels (7).

A differential device for distributing power to the front and rear wheels, a so-called center differential, is not equipped with emphasis on straightness during work traveling.

Further, bevel gears (9a) (9b) (9c) (9d) are used between the front propeller shaft (5) and the final drive device (6) of the front wheels (7) as shown in FIG. There is a differential type steering wheel speed increasing device (9) that can switch the speed ratio, and the bevel gear (9d) is connected to the dog clutch (10) by the front propeller shaft (5).
By connecting the bevel gear (9a) connected to the final drive device (6) by connecting to the input shaft (11) connected to the front propeller shaft (5), the power is transmitted at a rotation speed equal to that of the front propeller shaft (5). The bevel gear (9d) is a wet multi-plate type brake (12).
Then, by fixing it to the case (13) of the speed increasing device (9),
Power is transmitted to the final drive device (6) at the double rotation speed via the bevel gear (9a).

The speed ratio switching operation described above is performed by forming one tooth (10a) of the dog clutch (10) at one end of the slider (14) externally fitted to the input shaft (11) and the brake (12) at the other end. The pressure plate (12a) is formed, and the slider (14) is moved by the operation of the shift fork (15a) fixed to the shift shaft (15) through which the case (13) is inserted.

In the figure, (16) indicates a return spring for urging the slider (14) toward the dog clutch (10) to maintain a constant speed operation state.

A switching lever (17) is fixed to the end of the shift shaft (15) protruding outside the case (13) as shown in FIGS. 3 and 4, and the tip of the lever (17) is fixed. The push rod (2) of the speed ratio switching mechanism (19) is attached to the joint metal fitting (18) that is pivotally attached.
(0) is slidably inserted, and the shift shaft (15) is rotated by pushing the spring (25) in the buffer mechanism (24) provided in the middle of the rod (20). I have to.

At the base end of the push rod (20), a cam plate (2
3) is fixed, and the pitman arm (21a) of the steering gear box (21) is in the recess (23a) formed in the plate (23).
The intermediate shaft (22) that is interlocked with is inserted through the cam plate.
Set the upper and lower cam surfaces (23b) and (23c) of (23) to the steering wheel.
When (8) has a large serpentine angle, the upper and lower cam rollers (29a) and (29b) are coaxially supported by the intermediate shaft (22) at a predetermined distance.
Is pushed by the rotation of the intermediate shaft (22), and the push rod
Press (20) to activate.

Further, the upper and lower cam rollers (29a) (29b) are roller support plates (31) protruding from the pipe shaft (30) spline-fitted to the intermediate shaft (22).
The pipe shaft (30) is supported by the
(N) is slid in the axial direction with the wire (32) connected to it so that the upper and lower cam rollers (29a) and (29b) do not come into contact with the upper and lower cam surfaces (23b) and (23c). The speed-increasing operation of the direction wheels is detected by the detection mechanism (N) and the front axle case (3
It is designed to operate only when the inclination angle with 6) is within the preset angle.

The detection mechanism (N) is a rocking shaft (39a) in the front-rear direction projecting from the center of the front axle case (36) supporting the left and right front wheels (7) as shown in FIGS. 1 and 2. The front axle case (36) is rotatably supported by the front and rear brackets (38a) and (38b) suspended from the lower surface of the frame (37) so that the front axle case (36) can be tilted left and right. A cam plate (40) is fixed to the rear surface of the (36), and a cam follower (41) is inserted into the rear bracket (38b), and the follower (41) is connected to the wire (32).

In the figure, (42) indicates a spring for urging the wire (32) in the pulling direction and for bringing the cam follower (41) into contact with the cam plate (40). Allows the cam follower (41) to move the ridge (4) of the cam plate (40).
0a) is in contact, slide the pipe shaft (30) of the speed ratio switching mechanism (19) in the direction of the cam plate (23) to increase the speed of the steering wheel speed increasing device (9). The cam follower (4
When 1) is in contact with the valley (40b), pull the wire (32) and slide the pipe shaft (30) through the lever (43) to slide the cam plate (23) and the upper and lower cam rollers. (29a) and (29b) are not forcibly contacted with each other, and the steering wheel speed increasing device (9) is forcibly held in a constant speed operation state.

In addition, in FIG. 2, (a1) is the maximum horizontal tilt range of the front axle case (36), (a2) is a preset angular range, and the front axle case (3
Only when the horizontal inclination angle of 6) is within this range, the steering wheel speed increasing device (9) is in the speed increasing operation state. (a3) (a3) shows the angular range in which the speed increasing device (9) is forced to operate at a constant speed.

In the figure, (33) is the pitman arm (21a) and the intermediate shaft (22).
An intermediate link connecting the and, (34) is a drag rod, and (35) is a return spring of the tube axis (30).

[Brief description of drawings]

FIG. 1 is a side view of the safety device according to the present invention (cross section of a main part). FIG. 2 is an enlarged side view of the same. FIG. 3 is a side view of the speed ratio switching mechanism. FIG. 4 is a plan view of the same. FIG. 5 is a vertical sectional view of the steering wheel speed increasing device. FIG. 6 is a side view of the steering system. FIG. 7 is an overall side view of a tractor having a safety device according to the present invention. (N): Detection mechanism (4): Rear wheel (5): Front propeller shaft (6): Final drive device (7): Front wheel (8): Steering wheel (9): Steering wheel speed increasing device (17) : Switching lever (19): Speed ratio switching mechanism (36): Front axle case (39a) (39b): Swing shaft

Claims (1)

[Scope of utility model registration request] 1. A steering system capable of driving front and rear wheels (7) and (4) and capable of switching a speed ratio between a final drive device (6) of front wheels (7) and a front propeller shaft (5). The steering wheel speed increasing device (9) is changed from the constant speed operating state to the speed increasing operating state by the speed ratio switching mechanism (19) interlockingly connected to the steering wheel (8) through the wheel speed increasing device (9). Front wheels (7) in vehicles configured to be switched
The front axle case (36) supporting the shaft is pivotally supported so that the front axle case (36) can be tilted left and right about the swing shafts (39a) (39b) in the front-rear direction. The detection mechanism (N) for detecting the tilt angle is provided, and the detection mechanism (N) and the speed ratio switching mechanism (19) are interlockingly connected, so that the left and right tilt angles are larger than the preset angle. Time,
A vehicle safety device having a steering wheel speed increasing device (9) configured to automatically maintain a constant speed operation state.