JPS6157464A - Rear-wheel steering actuator for vehicles - Google Patents

Abstract

PURPOSE:To aim at the promotion of low-unit cost of production, by constituting an elastic body so as to produce preload by means of elastic deformation in the sheering direction and thereby simplifying its structure, in case of the above captioned actuator that makes rear wheels so as to be checked in a nonsteering position by the preload of the elastic body at normal temperature. CONSTITUTION:When hydraulic fluid is fed to a pressure chamber 25 from a control valve, for example via a port 27, a rear-wheel steering actuator 1 makes an actuating rod 17 being solidly provided with a piston 22 move to the right and steers rear wheels to the right. At the abovementioned, preload generating parts 29 and 30 for the actuating rod 17 are set up on both end faces of an outer tube of the actuator1. These preload generating aprts 29 and 30 are constituted of installing an eleastic body 33 composed of annular rubber interposingly between an inner sleeve 31 and an outer sleeve 32. And, in time of being built-in, the elastic body 33 makes both sleeves 31 and 32 relatively move axially in a direction where an overlapping value increases, whereby the elastic body 33 is made so as to be assembled in a state of being elastically deformed in the shearing direction.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to an actuator that controls rear steering of a vehicle.

(Prior art) Vehicles are required to maintain running stability under high pressure while turning.
In the case of low-ranking, it is required to be able to make small turns. For this reason,
It is considered that when the front wheels are steered by the steering wheel, the rear wheels are also steered at the same time.In this case, for the former purpose, the rear wheels are steered in the same direction and in the same phase as the front wheels, and for the latter purpose, the rear wheels are steered in the same direction as the front wheels. The wheels are steered in the opposite direction to the front wheels.

By the way, these rear wheel steerings are generally performed using hydraulic actuators. As an actuator of this kind, the applicant of the present application previously published Japanese Patent Application Laid-Open No. 58-21
We have already proposed something like the one shown in Publication No. 4470.

This actuator is configured to restrain the rear wheels to a non-steering position by preloading an elastic body (rubber bushing) in a normal state when no hydraulic pressure is supplied, and operates against the preload by supplying hydraulic pressure to steer the rear wheels. It is something.

(Problem that the invention seeks to solve).

However, in such an actuator, the elastic body is arranged so as to generate the above-mentioned preload by elastic deformation in the pressure a (extension direction). It became non-linear as shown by the dotted line α, causing the following problems.

In other words, in this case, in order to obtain the linear required steering amount (actuator stroke f) necessary to obtain a stable running condition, the supplied hydraulic pressure must be varied along nonlinear characteristics.However, in practice, It is extremely difficult to control the oil pressure in a non-linear manner, and therefore the amount of rear wheel steering must be approximately controlled, which inevitably results in inaccurate control.

In addition, it is difficult to determine the limit value of the actuator stroke amount.
It is necessary to separately provide a stopper in the rear wheel steering system to set a limit on the amount of rear wheel steering, resulting in the problem that the rear wheel steering system becomes expensive.

(Means for Solving the Problems) In the present invention, the elastic body is configured and arranged to generate the preload by elastic deformation in the shear direction.

(According to this configuration, when the actuator is supplied with hydraulic pressure and operates against the preload, the change characteristic of the stroke amount with respect to the supplied hydraulic pressure becomes a straight line, and the amount of rear wheel steering is uniquely determined by the supplied hydraulic pressure.) The elastic body itself can be used as a stopper to determine the limit of the actuator stroke, eliminating the need to add a separate stopper. Therefore, the rear wheel steering device can be constructed at low cost.

(Example) Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

1 and 2 show a rear wheel steering device configured to steer left and right rear wheels 2, 3 by an actuator 1 of the present invention. Both rear wheels 2 and 3 are rotatably supported by wheel support members 4 and 5, respectively, and these members are supported in the longitudinal direction of the vehicle body 8 (arrow a is toward the front of the vehicle body) by radius rods 6 and 5, respectively. Chiral rod performed 9. IO and 11
．． Struts 13t14 are provided which support the vehicle body 8 in the lateral direction by 12 and extend to the vehicle body 8 above the members 4 and 5, and suspension springs 15 and 16 of these struts are provided.
The member 4.5 is elastically supported in the vertical direction of the vehicle body.

The lateral rods 10 and 12 are interconnected by the actuating rod 17 of the actuator 1, and both ends of the actuating rod are connected to the lateral rods to and 12 by universal joins 18 and 19, respectively. The actuator 1 is attached to the vehicle body 8 via a pair of brackets 21 fixed to an outer cylinder 20 thereof.

Next, the detailed structure of the actuator 1 will be explained in detail with reference to FIG. 3. The actuating rod 17 penetrates an outer cylinder 20 and integrally has a piston 22 that slides inside the outer cylinder. A guide ring 28 and a seal ring 24 are fitted to both ends of the outer @ 20 to set pressure chambers 25 t 26 on both sides of the piston 22, and the guide ring 23 guides the actuating rod 17, while the seal ring 24 releases pressure The chambers 25 and 26 are sealed. Further, the outer cylinder 20 is provided with hydraulic pressure supply bows 27 and 28 that open into the chambers 25 and 26.

Preload generating portions 29 and 80 for the actuating rod 17 are provided on both end faces of the outer cylinder 20, respectively, and since these have a similar configuration with left-right symmetry, only the right preload generating portion 80 will be described. Actuation rod 1 protruding from outer cylinder 20
7, an outer sleeve a2 is provided concentrically with the inner sleeve 81, and these sleeves 31, 82
An elastic body 88 made of annular rubber is interposed between the two, and
The inner and outer peripheral surfaces of the elastic body are glued to the corresponding sleeves 81 and 32, respectively. The relative positions of the sleeves 31 and 32 in the axial direction are set so that the free shape of the elastic body 83 is normally set so that the amount of overlap is smaller than that shown in the figure, and when assembling the two sleeves 31 and 32 as shown in the figure, the above-mentioned overlap is increased. The assembly is performed in a state where the elastic body 83 is elastically deformed in the shearing direction by relatively moving the sleeves 31 and 42 in the axial direction. Therefore, this assembly is performed on the rear outer sleeve 82.
is pressed against the seal ring 24, and the inner sleeve 3
1 is pressed against the universal joint 19, the right preload generating section 30 applies a preload to the actuating rod 17 in the direction of the arrow, and the left preload generating section 29 applies a preload in the direction C opposite to the actuating rod 17. Grants an equivalent preload of .

In addition, both ends of the outer m2o and the corresponding latera A10
0 and 12, respectively, are provided with dust boots 34 (not shown in the left dust boot, which provide a dustproof and universal joint between the inner sleeve 31 and the operating lid 17) 18 and 19. Do the following.

The supply and discharge of hydraulic pressure to and from the actuator T is controlled by an electromagnetic spool pulp 35 shown in FIG.

This pulp is supplied to a pump 38 which is equipped with a splinter center type spool 86 and which sucks oil in an oil reservoir 87.
The oil discharged from the inlet boat is supplied to the inlet boat 365L, and unnecessary oil is drained from the drain boat 85b.

850 and returns to the oil reservoir 37. spool) i3
6b and 850, and when solenoid a9 is energized, the amount proportional to the electromagnetic force moves to the left in the diagram and exit boat 3
5d, and when the solenoid 40 is energized, selectively outputs hydraulic pressure to the right-hand boat 35e in ff1fN proportional to the electromagnetic force, and makes the hydraulic pressure value proportional to the electromagnetic force. shall be.

In addition, such a bubble a5 has its exit bow) 35 e.

35d respectively for hydraulic supply boat 2 of actuator 1,
28 and used to control the actuator.

Energization, de-energization and energization of solenoid 89.40 111
! The magnetic force) is controlled by a mounting roller 41, and a signal from a steering angle sensor 43 that detects the operation 11 of the steering wheel 42 (front wheel steering ff1) is input to this controller. In response to this input information, the controller 41 controls the rear wheels 2,
It is determined whether the boat 35 (1, 3
If the rear wheels 2 and 8 are to be steered to the left without outputting hydraulic pressure from any of the rear wheels 58 and the rear wheels 2 and 8 are to be turned to the left as described later, the solenoid 40'rr - set to the required steering amount. The boat 36e outputs the corresponding hydraulic pressure by energizing the boat 36e in accordance with this, and steers the rear wheels as described later.If the rear wheels 2 and 3 are to be steered to the right, the solenoid 39 is activated according to the required steering amount. By energizing, a corresponding hydraulic pressure is output from the boat asa, and the rear wheels are steered as described later.

The operation of the above embodiment will be explained next. Actuator 1 moves from pulp 85 boats (asa, ase to boats) 27.
28, the preload b of the elastic body 88 is applied to the actuating rod 17.

C (see section ariiJ). By the way, since these preloads b and c are in opposite directions as described above, the operating rod 17 is in the neutral position, and the rear wheels 2 and 8 are kept in the non-steered state shown by the solid lines in FIG. . Furthermore, even if a kick pack is input from the road surface to the rear wheels 2 and 3 while driving, the toe angle of the rear wheels 2 and 3 is prevented by the preloads b and c, and the actuator 1 prevents the rear wheels from being inadvertently steered. It is possible.

When hydraulic pressure is supplied from the boat 85e to the pressure chamber 25 via the boat 27, the actuator 1 uses this hydraulic pressure to move the actuating rod 1f against the preload, and as shown in FIGS.
The image is shown in the figure. This allows the lateral rod 10.12
Since rear wheel 2. is also displaced in the same direction, rear wheel 2. A can be steered to the right as shown by the two-dot chain line in FIG. The amount of steering at this time is determined by the above-mentioned oil pressure value, and the inner sleeve 81 of the preload generating section 29 located on the left side determines the limit of the rear wheel steering by the seal ring 24 (the eighth
In the figure, only the right sealing ring 24 is shown).

Conversely, when hydraulic pressure is supplied from &-) 85d to the pressure chamber 26 via the boat 28, the actuator 1 uses this hydraulic pressure to move the operating rod 17 to the left in FIGS. 1 to 8 against the preload. . This allows the lateral rod lo,
Since 1g is also displaced in the same direction, the rear wheels 2 and 8 can be steered to the left. The amount of steering at this time is also determined by the value of the oil pressure, and the limit of such rear wheel steering can be determined by the collision T of the inner sleeve 31 of the preload generating section 80 on the right side against the seal ring 24.

During such rear wheel steering, the supply oil pressure of the actuator 1 is
Since the preloads b and c are imparted by the elastic deformation of the elastic body 33 in the shear direction, the change characteristics of the stroke amount are direct as shown by the solid line β in FIG. This allows the rear wheel steering amount to be accurately controlled. In addition, the inner sleeve 31 of the pre-opening/dead generating portion 2g, 80 collides with the seal ring 24, thereby increasing the limit of the stroke amount (rear wheel steering amount) to δ in FIG.
, -δ, can be determined in a known manner, so there is no need to provide a separate stopper for this purpose, and the rear wheel steering system can be constructed at low cost. Figures 4 and 5 show another example of the actuator of the present invention. By way of example, elastic bushings 44 are used to connect both ends of actuating rod 17 to lateral rod 10912 (only the latter lateral rod 12 is shown in the drawing). This elastic bushing consists of an inner ring 44a, an outer ring 44b, and an annular rubber body 440 interposed between these rings.
Weld b to the lateral rod.

Then, the yoke 45 is fixed to the end surface of the actuating rod 17,
An elastic bushing 44 is inserted between the opposing legs, and
By inserting bolts 46 through these legs and the inner ring 44&, both ends of the actuating rod 17 are connected to the lateral rod. Further, an O-ring 47 is provided at the fitting portion between the inner sleeve 81 and the operating rod 17, and a portion of the outer sleeve 32 is fitted into the outer cylinder 20, and an O-ring 48 is also provided at this fitting portion.

In the configuration of this example, the O-rings 47 and 48 perform the oil leakage function and prevent dust from entering, and the elastic bushings 44
Since 84 does not require dust protection, it is shown in Figure 8.
Since a dust boot as shown in FIG. Further, the elastic bushing 44 can block vibrations directed from the rear wheel toward the operating rod 17 due to the vibration-proofing function of the annular rubber body 440.
This can have the effect of alleviating vibration transmission to the vehicle body.

FIG. 6 shows still another example of the present invention, in which the outer cylinder 20
The outer sleeve 32 is fitted over its entire length into this extended end, and the outer sleeve is screwed onto the extended end of the outer cylinder 20 between the cap 49 and the seal ring 24. position. In this case, since the outer sleeve 32 is firmly held in the radial direction within the extension end of the outer cylinder 20, the outer sleeve 32 axially supports the actuating rod 17 via the elastic body 33 and the inner sleeve 81. It also serves as a guide. Therefore, fJ for this guide? There is no need for a guide ring as shown by 28 in FIG.

(Effect of the invention JA!:) As described above, the rear wheel steering actuator 1 of the present invention has the elastic body 88 configured and arranged so as to generate the preloads b and c by elastic deformation in the shearing direction. The change characteristic of the stroke amount with respect to the supplied oil pressure can be made linear as shown by β in FIG. Wheel steering amount control can be performed accurately. Further, by arranging the elastic body 38 as shown in the figure, for example,
The actuator itself can also be used as a stopper for the actuator stroke limit, and the stroke limit can be set, for example, by δ as shown in Fig. 7.
, -δ, and there is no need to separately provide a stopper for this purpose, and the rear wheel steering device can be constructed at low cost.・

[Brief explanation of the drawing]

FIG. 1 is a plan view of a rear wheel steering device equipped with the actuator of the present invention, and FIG. 2 is a rear view of the same as seen from the rear of the vehicle.
FIG. 8 is a partially cutaway enlarged side view of the actuator of the present invention used in the apparatus shown in FIGS. 1 and 2, FIG. 4 is a partially enlarged sectional view showing another example of the actuator of the present invention, and FIG. Similarly, FIG. 6 is a partially enlarged sectional view similar to FIG. 4 showing still another example of the present invention, and FIG. 7 shows the change characteristics of the stroke amount with respect to the oil pressure supplied to the actuator in the conventional case. FIG. 4 is a diagram comparing and showing the case of the present invention. 1°... Actuator of the present invention 2, 8... Rear wheel 4
．． 5 Wheel support member 6, 7... Radius rod 8
...Vehicle body 9-12...Lateral rod 13.14...Strut 17...Operating rod 18.1
9...Universal joint 20...Outer cylinder
21...Bracket 22...Piston
23...Guide ring 24...Seal ring

Claims (1)

[Claims] 1. An actuator for steering rear wheels of a vehicle, which normally restrains the rear wheels to a non-steering position by preloading an elastic body, and operates against the preload by supplying hydraulic pressure to steer the rear wheels, An actuator for steering a rear wheel of a vehicle, characterized in that the elastic body is configured and arranged to generate the preload by elastic deformation in the shear direction.