JPS61295174A - Four-wheel steering gear of four-wheel vehicle - Google Patents

Abstract

PURPOSE:To facilitate the setting of turn steering characteristic by taking out the reciprocating linear motion of a vehicle body in a substantial front and rear direction from a front wheel steering mechanism, and converting the reciprocating linear motion to the rotating motion, and making the turn steering of rear wheels by means of the rotating motion. CONSTITUTION:Splines 35s are formed in the outer periphery of the rear portion of a slide shaft 35 which is adjustable in the length, and further a pin 36 is inserted into the rear end in a vertical direction. And the pin 36 is fixed by fastening a bolt 37 from the rear end surface of the slide shaft 35, and the upper portion of the pin 36 is upwardly projected from the shaft 35. The rear portion of the slide shaft 35 is inserted into a cylindrical case 42, and the splines of the shaft 35 are fitted into the splines provided in the front wall of the case 42 to make the slide shaft 35 be slidable against the case 42 only in a front and rear direction. A drum 43 is rotatably inserted into the case 42, and a groove 44 is formed on the drum 43, and the pin 36 is engaged with the groove. A rear steering arm 47 is fitted into the outer periphery of the rear portion of the drum 43 with the splines.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a four-wheel steering system for a four-wheel vehicle.

(Prior Art and Object of the Invention) A vehicle is equipped with a straddle-type seat and is equipped with a steering transmission mechanism that mechanically interlocks a front wheel steering mechanism from a steering wheel to a front wheel and a rear wheel steering mechanism, thereby enabling four-wheel steering. A straddle-type four-wheeled vehicle is disclosed in Japanese Patent Application Laid-Open No. 58-182685, and its steering transmission mechanism is constituted by a link type mechanism.

An object of the present invention is to extract reciprocating linear motion in a substantially longitudinal direction of the vehicle body from a front wheel steering mechanism in place of a conventional link type steering transmission mechanism in a four-wheeled vehicle, convert this reciprocating linear motion into rotational motion, and convert the reciprocating linear motion into rotational motion. To provide a four-wheel steering device using a novel system in which rear wheels are steered by interlocking rotation.

(Structure and operation of the invention) Therefore, the present invention provides a handle (3) in the four-wheeled vehicle.
Front wheel steering mechanism (29) from 2) to front wheels (2), (2)
A steering transmission mechanism (34) that mechanically interlocks the rear wheels (3) and the steering mechanism (18) of (3) is connected to the front wheel steering mechanism (2).
A slide shaft (35) is connected to the rear wheel steering mechanism (18) and is connected to the rear wheel steering mechanism (18) to convert the reciprocating linear motion of the slide shaft (35) into rotational movement. and a rear wheel steering angle generating mechanism (41) that steers the rear wheels (3), (3).

The rear wheel steering angle generating mechanism (41) has a pin (36) provided on the slide shaft (35), and a pin (36) provided on the slide shaft (35).
36) and provided with a groove (44) intersecting the axis center line (L) of the slide shaft (35).
Equipped with.

The linear slow movement of the slide shaft (35) is achieved by the pin (36) and groove (
44), the rotation of the drum (43) is linked, and the rear wheels (3), (3) are steered.

Especially the rear wheel (3) by simply changing the shape of the groove (44).

(3) can be steered to the same phase or opposite phase as the front wheels (2), (2), from the same phase to the opposite phase, or from the opposite phase to the same phase, and the rear wheels (3), (3) The steering characteristics can be easily set.

(Example) Examples will be described below based on accompanying drawings.

Figures 1 to 5 are an exterior W side view, a perspective plan view, and an exterior side view from the right side of the four-wheel steering (4WS) and four-wheel drive (4WD) straddle-type four-wheeled vehicle. , a perspective side view and an exterior side view from the left side of the vehicle body, front wheels (2), (2) and rear wheels (3), (3) are suspended on the front, rear, left and right sides of the frame (1), and the frame (1) )l- is equipped with a body cover (4), and the body cover (4) is equipped with a front fender (4f).
), (4f) and rear 7x (4r).

(4r) are integrally formed. Here, the wheels (2w) and (3w) of each front wheel (2) and rear wheel (3) are equipped with ultra-low pressure balloon tires (2t) for driving on rough terrain.
3t) is attached.

An engine (5) is mounted at the bottom of the frame (1), approximately midway between the front and rear and left and right, which lowers the center of gravity of the vehicle. A straddle-type seat (8) is arranged in the frame (D, +-, section), and two I-steps (7), (
7) is provided. The crankcase (5C) of this engine (5), the cylinder part (5s) that stands up at I- is tilted forward, and a transmission case (5m) is integrally provided at the rear of the crankcase (5C). (
A gear box (8) serving as a power take-off section is attached to the left side surface of the motor.

A rear propulsion shaft (11) and a front propulsion shaft (21) are incorporated into this gearbox (8), and both propulsion shafts (11) and (21), which form a power transmission mechanism to the axle, are on the left side of the engine (5). The rear end of the rear propulsion shaft (11) is located almost parallel to the left-right center line (C) of the vehicle body, and the differential case (12)
The front end of the front translation shaft (21) is assembled into the front differential case (22). Both differential cases (+2)
, (22) have left and right drive shafts (+3) and (14), respectively.
).

(23), (24) are incorporated, and each drive shaft (13), (
+4).

At the outer ends of (23) and (24) are universal joints (i5) and (
15), (25).

(25) through axles (1B), (Iff), (2B)
, (2B) are respectively concatenated.

On the other hand, a bar handle (32) is fixed to the -L end of the steering shaft (31), which is inserted and supported by the head pipe (1h) at the front end of the frame (1).
) is the center! jl' (C), a steering arm (33) is fixed to its lower end, and left and right tie rods (27), (27) are pivotally attached to the rear of this steering arm (33). . Also the front wheel (2).

The axle (2B), (213) of (2) is the knuckle arm (
28).

(28), respectively supported by this knuckle arm (28).
Tie rods (2?) and (2?) are pivotally attached to B) and (28).

In this way, from the bar handle (32) to the front wheels (2), (2)
A front wheel steering mechanism (29) is constructed.

Furthermore, the axles (18), (1B) of the rear wheels ('3), (3) are also supported by the knuckle arms (18), (18), and the tie rods (1B) are attached to the knuckle arms (1B), (+8).
7) and (17) are pivotally connected, and thus the rear wheel steering mechanism (1
8) is constructed.

The rear wheel steering mechanism (19) is mechanically interlocked with the front wheel steering mechanism (29) and the steering transmission mechanism (34).

That is, a protrusion (33a) extending to the right side is formed on the steering arm (33), a slide shaft (35) is pivotally connected to this protrusion (33a), and the slide shaft (35) is connected to the engine (5). ) on the right side, approximately parallel to the center line (C),
■Arrange one above the footstep (7) so as to keep it almost horizontal. The rear part of this slide shaft (5) is incorporated into the rear wheel steering angle generating mechanism (41), and the rear steering arm (4) which forms the output part of this rear wheel steering angle generating mechanism (41) is assembled.
7), pivot the left and right tie rods (+7) and (+7).

The rear wheel steering angle generating mechanism (41) is as shown in Figs. 6 and 7, and has a slide shaft (35) formed with a spline (35s) on the rear outer periphery whose length can be adjusted, and a vertical spline (35s) on the rear end. Insert the pin (36) in the direction, and tighten the pin (37) from the rear end surface of the slide shaft (35) to fix the pin (36).
A portion of the pin (3B) protrudes above the shaft (35). The rear part of the slide shaft (35) is assembled into a cylindrical case (42) supported by the vehicle body, and the spline (42s) of the shaft (35) is connected to the spline (42s) provided on the front wall of the case (42).
35s) and slide the slide shaft (
35) can be slid only in the front and rear directions.

Then, the drum (43) is rotatably assembled into the case (42) from the rear via the front and rear bearings (45), (aa). A groove (44) extending substantially in the front-rear direction is formed in a portion of this drum (43). As shown in Fig. 7, this groove (44) has a straight part (44a) extending along the axis center line (L) I: and a straight part (44a) extending smoothly from the front of the straight part (44a) toward the side of the vehicle body. a continuous front curved portion (44f);
It consists of a straight portion (44a) and a rear curved portion (44r) that smoothly continues from the rear toward the other side of the vehicle body. The pin (36) is placed in the groove (44) intersecting the axis center line (L).
engage.

Furthermore, a drum (4) protrudes from the rear bearing (46).
Spline-fit the rear steering arm (47) to the outer circumference of the rear end of the drum (43), and fit the nut (4) to the outer circumference of the rear end of the drum (43).
8), and the left and right tie rods (17) are pivotally connected to the lower part of the rear steering arm (47).

In the embodiment, the length of the tie rods (17) and (17) can be adjusted using turnbuckles as shown in Figure 6, and the length of the tie rods (35) and the case (42) can be adjusted.
A flexible dust boot (48) is placed between them.

In this way, 4W with the number of midship engines (5)
In the S straddle type four-wheel vehicle, the midship engine (
5) The gear case (8
) to the front wheels (2), (2) and rear wheels (3), which are the driving wheels.
(3) axle (Ill), (18), (2B),
(2B) Front and rear propulsion shafts (It) that form the power transmission mechanism
, (21), the steering transmission mechanism (34) that interlocks and connects the front wheel steering mechanism (29) and the rear wheel steering mechanism (19) is disposed on the other side of the engine (5). The mold part balance is improved.

In addition, since the steering transmission mechanism (34) is placed on one side of the footstep (7), the height from the ground is secured, and the slide shaft (35) forming the steering transmission mechanism (34) and the rear wheel steering angle generating mechanism (41) can be protected.

The rear wheel steering angle generating mechanism (41) is connected to a pin (3B) provided on a slide shaft (35) that is movable only in the front and back direction in response to the steering arm (33), and a tie rod (+7) for the rear wheel. , (17) are jointed or composed of grooves (44) formed in the drum (43) integrated with the steering arm (47), the slide shaft (35)
) can be converted into a rotational movement of the drum (43) to steer the rear wheels (3), (3).

In the embodiment, the pin (36) is inserted into the straight portion (44a) of the groove (44) when the vehicle is traveling straight without steering the front wheels (2), (2).
If the initial setting is at the center of the slide axis (
35) moves back and forth, and the pin (36) engages with the front and rear curved portions (44f) and (44r) of the groove (44), causing the drum (43) to rotate, and the rear drum (43) to rotate together with this. Tie rod (17) by steering arm (47),
(+7) and knuckle arms (18), (1B) to steer the rear wheels (3), (3) in opposite phase to the front wheels (2), (2) with nonlinear characteristics.

Also, if the shape of the groove (44) is changed, the front wheels (2), (2)
The rear wheels (3), (3) can be steered in the same phase, from the same phase to the opposite phase, or from the opposite phase to the same phase, and furthermore, the steering characteristics of the rear wheels (3), (3) can also be changed arbitrarily and is easy to set.

By the way, according to the shape of the groove (44) in the example, since the intermediate straight part (44a) is formed long along the axis center line (L), the pin (36) is not engaged with this straight part (44a). In other words, in the small steering angle range of the steering wheel (32), in other words, in the small steering amount range of the front wheels (2), (2), the rotation of the rear wheels (3), (3) is The steering angle is kept at zero, and no rear wheel steering is performed, similar to normal front wheel steering (2WS).

As the steering wheel steering angle (front wheel turning amount) increases, the front and rear curved parts (44f) and (44r)
When engaged, the rear wheels (3), (3) engage the front wheels (2),
It is steered with a nonlinear steering characteristic in the opposite phase to (2).

Therefore, the rear wheels (3), (3) are generally used only in the large steering angle range of the steering wheel (32) when driving at low speeds.
2), the turning radius of the vehicle can be reduced by steering in the opposite phase to (2).

In this way, the large steering angle range of the steering wheel (32) improves the maneuverability of the vehicle, and the rear wheel ( 3), maneuverability similar to 2WS without steering is obtained.

(Effects of the Invention) As described above, according to the present invention, a steering transmission mechanism that mechanically interlocks the front wheel steering mechanism from the steering wheel to the front wheels and the rear wheel steering mechanism is provided, thereby enabling four-wheel steering. In four-wheeled vehicles, there are 11 slide shafts that are connected to the front wheel steering mechanism and perform reciprocating linear movement in the approximately longitudinal direction, and the rear wheel steering mechanism that converts the reciprocating linear motion of the slide shaft into rotational motion. Since the steering transmission mechanism is composed of a rear wheel steering angle generating mechanism that steers the rear wheels by turning the steering wheel, the linear slow motion taken out from the front wheel steering device can be converted into rotational interlocking for steering the rear wheels. According to the embodiment, steering characteristics such as the steering direction and amount of steering of the rear wheels can be easily set by simply changing the shape of the groove in which the pin engages.

[Brief explanation of drawings]

Fig. 1 is an external plan view of a straddle-type four-wheeled vehicle with 4WS and 4WD, Fig. 2 is a perspective side view of the same, Fig. 3 is an external side view of the vehicle from the right side, and Fig. 4 is a perspective side view of the same. Fig. 5 is an external side view of the vehicle from the left side, Fig. 6 is a perspective view of the rear wheel steering angle generating mechanism,
FIG. 7 is a developed sectional view of the same. In the drawings, (2) and (3) are wheels, (5) is a Mitsudoshi Lab engine, (6) is a straddle type seat, (7) is a foot step, (8) is a power take-off part, and (11) is a saddle type seat. ), (21) are propulsion shafts, (IB), (2B) are axles, (17), (27)
is the tie rod, (18) and (28) are the knuckle arms,
(18) is a rear wheel steering mechanism, (28) is a front wheel steering mechanism, (
31) is the steering shaft, (32) is the handle, (33)
) is the steering arm, (34) is the steering transmission mechanism, (
35) is the slide shaft, (36) is the pin, (41) is the rear wheel steering angle generation mechanism, (42) is the case, (43) is the drum,
(40 is a groove, (47) a beam steering arm.

Claims (1)

[Scope of Claims] 1. A four-wheeled vehicle capable of four-wheel steering by providing a steering transmission mechanism that mechanically interlocks a front wheel steering mechanism from a steering wheel to a front wheel and a rear wheel steering mechanism, transmission mechanism,
A slide shaft is connected to the front wheel steering mechanism and performs reciprocating linear motion in the approximately longitudinal direction of the vehicle body, and a slide shaft is connected to the rear wheel steering mechanism and converts the reciprocating linear motion of the slide shaft into rotational motion to drive the rear wheels. 1. A four-wheel steering device for a four-wheel vehicle, comprising a rear wheel steering angle generating mechanism that steers a rear wheel steering angle. 2. The rear wheel steering angle generating mechanism includes a pin provided on the slide shaft, and a drum engaged with the pin and provided with a groove intersecting the axial center line of the slide shaft. A four-wheel steering device for a four-wheel vehicle as described in Section 3.