JPH035351B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an improvement in a steering device for front and rear wheels of a vehicle.

(Prior Art) In the four-wheel steering system of a vehicle, the present applicant has filed a patent application as one of the so-called symmetrical function type steering systems in which the rear wheels have the same maximum steering angle as the front wheels in the same phase and in the opposite phase. We proposed No. 1983-93394 (patent application No. 58-209657). In this steering system, a joint member that connects and supports the left and right rear wheel tie rods is rotatably fitted onto an eccentric shaft installed at the rear end of the input shaft of the rear wheel steering system, which rotates in conjunction with the steering wheel. Furthermore, this joint member is supported on the vehicle body via a link mechanism to control vibrations of the joint member.

Furthermore, prior to this, the applicant had filed a patent application in 1983-
No. 127188 (Japanese Unexamined Patent Publication No. 58-30869) proposes a steering system in which the eccentric shaft and the joint member are slidably engaged and the joint member can only be moved in the left and right directions.

(Problems to be Solved by the Invention) The steering system disclosed in Japanese Patent Application No. 57-93394 has the following technical problems.

First of all, since a link mechanism is used to restrict the swinging of the joint member, it is necessary to take up space for this purpose, making it difficult to assemble the device as a whole, making it difficult to check the performance before assembling it into the vehicle, and making it difficult to attach the link to the vehicle body. Installation is difficult both in terms of strength and precision. In addition, since a link mechanism that extends to one side of the vehicle body is used, the structure is asymmetrical, and the relationship between the rotation of the input shaft and the left-right position of the ball joint is slightly different between counterclockwise and clockwise, resulting in errors in left-right steering angle changes. occurs.

Specifically, the tie rod for the rear wheel is connected to the left and right sides of the joint member via a ball joint, but since the joint member performs a composite movement in the left-right and up-down directions, the ball joint also moves up and down. There is a difference in setting the rear wheel steering angle. In addition, if the ball joint is placed far from the center of the joint member, the force applied to the link mechanism will increase and there will be limits in terms of strength and rigidity.Therefore, there are various restrictions when determining the position of the ball joint to match the suspension. It is difficult to freely combine it with different types of suspensions.

Furthermore, since the input shaft and the joint member are all sliding in the thrust direction, friction is large, accuracy is difficult to achieve, play is unavoidable, and there is a possibility of the occurrence of hitting noise.

In addition, the clearance of all roller bearings used for input shafts, eccentric shafts, and joint member bearings cannot be adjusted, so extreme precision is required to assemble them without play, resulting in high costs and time-consuming processing and inspections. .

Furthermore, since the input shaft is supported by being attached to the vehicle body using a relatively thin holder, force is concentrated and soft mounting rubber cannot be used, making it difficult to insulate sound and vibration.

On the other hand, according to the steering system disclosed in Japanese Patent Application No. 56-127188, since the circumference of the eccentric shaft is directly engaged with the joint member, precision is required for centering, and in particular, the generation of clearance in the radial direction at the engagement part is difficult. There are technical challenges that are difficult to avoid.

The present invention has been made to solve the technical problems in both the above-mentioned steering systems, and is the first specific invention.
The object of the invention is to have the advantages of both steering systems at the same time, namely to achieve compactness of the entire device, elimination of errors in left and right steering angle changes as well as errors in set steering angles, and adaptation to various types of suspensions. In addition, it realizes automatic alignment of the eccentric shaft and joint member, and also allows the use of soft mount rubber, which is advantageous in isolating noise and vibration.Furthermore, it is possible to adjust the assembly of the input shaft and joint member. To provide a steering device for front and rear wheels that is highly practical.

A second invention having the first invention as a main part further provides a steering device for front and rear wheels that can maintain zero clearance between an input shaft and a joint member during long-term use. purpose.

(Means for Solving the Problems) Therefore, in the first aspect of the present invention, an eccentric shaft 22 provided at the rear end of an input shaft 20 of a rear wheel steering system that rotates in conjunction with a steering wheel, A joint member 30 that connects and supports the rear wheel tie rods 15, 15 and is supported by the vehicle body so as to be horizontally movable in the left and right direction.
In the front and rear wheel steering device in which the eccentric shaft 22 and the joint member 30 are slidably engaged with each other, the engagement portions between the eccentric shaft 22 and the joint member 30 are located on the right and left sides of the eccentric shaft 22 and are formed in a vertical direction. The present invention is characterized in that it is configured as a tapered engaging portion 37 and is provided with adjusting means for adjusting the position of the input shaft 20 in the front-rear direction.

Specifically, the adjustment means includes angular bearings 28, 29, 123 interposed between the input shaft 20 and its bearing holder 42, the bearing holder 42,
Sleeve 50, 1 screwed into 142 so that it can move forward and backward
50, this sleeve and the outer ring 2 of the bearing.
Thrust washer 51,1 interposed between 9,125
It consists of 51.

Furthermore, a second invention is characterized in that, in addition to the configuration of the first invention, a preload means for urging the input shaft 20 toward the joint member 30 is provided.

Specifically, the preload means includes the sleeve 5
0,150 and the washer 51,1
Coil spring 52,1 that presses 51 backward
It is 52.

(Function) In this way, since the eccentric shaft 22 and the joint member 30 are slidably engaged at the left and right taper engaging portions 37, automatic centering can be performed by the centripetal action of the tapered engaging portions 37, especially for the rear wheels. The left and right rudder angle changes and the set rudder angle can be maintained with high precision.

Since the adjusting means for adjusting the longitudinal position of the input shaft 20 is provided, the input shaft 20 can be moved toward the rear wheel and the engagement state of the tapered engaging portion 37 can be properly initialized.

Furthermore, since a preload means is provided to urge the input shaft 20 in the direction of the joint member 30, the engagement state of the taper engaging portion 37 can be maintained properly at all times due to the pressing force, and the taper engaging portion 37 can be kept in an appropriate engaged state at all times during long-term use. 37 clearance can be maintained at zero in both the radial and thrust directions.

(Embodiments) Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a cross-sectional view of the steering angle function generating mechanism of the rear wheel steering system showing the main part of the present invention, and FIG.
The line sectional view and FIG. 4 are schematic perspective views of the entire steering system.

As shown in Fig. 4, the support shaft 2 of the handle 1 is built into a rack and pinion type gear box 3, and tie rods 5, 5 are connected to both ends of the rack shaft 4, and the front wheels 7, 7 are connected to the tie rods 5, 5. The supported knuckle arms 6, 6 are connected, and as is known, the front wheels 7,
7 is steered in the steering direction of the handle 1.

A long linkage shaft 10 is connected to a pinion shaft 8 led out rearward from the gearbox 3 via a universal joint 9, and a universal joint 11 is connected to the rear wheel of the shaft 10.
An input shaft 20 of a rear wheel steering system is connected thereto.
As shown in FIG. 1, a flange 21 is formed at the rear end of this input shaft 20, and an extremely short eccentric shaft 22 is provided protruding from this flange 21.

On the other hand, as shown in FIG. 4, tie rods 15, 15 connected to knuckle arms 16, 16 supporting rear wheels 17, 17 are connected and supported to both ends of a joint shaft 30 via ball joints 13, 13, respectively. As shown in FIG. 1, an engaged member 31 is fixedly provided at the center of the joint shaft 30. As shown in FIG. That is, the engaged member 31 is connected from the rear with two bolts 39,
At 39, it is fixedly integrated with the central part of the joint shaft 30, and female tapered surfaces 34, 34 facing forward are formed on opposing surfaces of the two right and left vertical walls 33, 33 that protrude forward of the joint shaft 30.

The engaging member 24 is mounted on the eccentric shaft 22 with balls 23 interposed therebetween, and the eccentric shaft 22 is provided with a contact type angular bearing. Male tapered surfaces 26, 26 facing rearward are formed on the side surfaces of the left and right vertical wall portions 25, 25 of this engaging member 24.
Stopper protrusions 27, 27, 27, 27 protrude from the upper and lower ends of the male and female tapered surfaces 26, 26.

Furthermore, when the engaging member 24 and the engaged member 31 are engaged and assembled, both the left and right tapered surfaces 26, 3
As shown in FIG. 2, rollers 36 . . . , 36 .

The above input shaft 20 and joint shaft 30 are connected to a box 41 at the center and pipes 4 at the front and left and right sides.
It is supported by a holder 40 integrally formed with 2, 43, 43. That is, with the engaged member 31 facing inside the box 41 of the holder 40, the joint shaft 30 is inserted into the left and right pipes 43, 43 with metal bearings 44, 4.
4, it is pivoted so that it can slide horizontally from side to side. Then, with the eccentric shaft 22 facing inside the box 41, the engaging member 2
4 to the engaged member 31, the rollers 36..., 36
. . . to connect the input shaft 20 to the front pipe 4.
It is rotatably supported within 2.

Specifically, the input shaft 20 is supported by installing a ring 29 on the front part of the flange 21 at the rear end with balls 28 interposed therein, a contact type angular bearing, and attaching the ring 29 to the pipe 42. Fits lightly into the inner periphery of the proximal end. Then, a thrust washer 51 is applied to the front surface of the ring 29, a sleeve 50 is screwed and inserted into the pipe 42, and the rear end of the sleeve 50 is abutted against the washer 51. A space is provided between the sleeve 50 and the input shaft 20, a coil spring 52 is inserted into this space, and the spring 52 is compressed between the washer 51 and the seat 53 which is regulated by a step 54 at the intermediate portion of the inner circumference of the sleeve 50. The ring 51 is preloaded so as to urge the ring 51 rearward. Furthermore, a lock nut 55 is screwed onto the sleeve 50. Further, a roller bearing 56 is interposed between the front end of the sleeve 50 and the input shaft 20, and a seal cap 57 is mounted on the roller bearing 56.

In this way, the opening of the box 41 is closed with the cover 45, the input shaft 20 is aligned with the left and right center line of the vehicle body, and the left and right pipes 43, 43 are connected to the vehicle body side bracket 4 by interposing soft mounting rubbers 46, 46.
Supported by 7,47. In addition, the left and right ball joints 13,1
3 is covered with compact rubber boots 48, 48 which are fastened with bands to the end of the pipe 43 and the end of the tie rod 15, respectively.

The settings of the above steering system are such that the eccentric shaft 22 is initially set vertically to the input shaft 20, for example, vertically downward as shown in FIG. Set the crank to rotate clockwise in Figure 2.

When the handle 1 is rotated, the input shaft 20 of the rear wheel steering system is rotated in conjunction with the linkage shaft 10 connected to the front wheel steering system, and the eccentric shaft 22 integrated therewith is rotated by a crank.

This crank movement of the eccentric shaft 22 causes the eccentric shaft 22 to
An engaging member 24 provided on the top via a ball 23...
From there, rollers 36..., 3 are placed on both left and right sides of each other.
6... are converted into a left-right direction movement of the engaged member 31 which is engaged in vertical sliding engagement.
That is, the joint shaft 30 to which the engaged member 31 is fixed moves in the left-right direction, and the rear wheel tie rods 15, 15 connected to both ends thereof move in the left-right direction, thereby causing the rotation of the rear wheels 17, 17. The rudder is done.

Therefore, as the crank rotates from the initial position of the eccentric shaft 22, if the rotation angle is less than 180°, the rear wheels 17, 1
7 is steered in the same direction as the front wheels 7, 7. In this case, the rear wheel steering angle is maximum at 90°, and when it exceeds 180°, it is steered in the opposite direction, and the rear wheel steering angle is 270°. is the maximum, and the maximum steering angles of the rear wheels 17, 17 in the same phase and in the opposite phase as the front wheels 7, 7 are equal.

In this way, by operating the steering wheel at a small steering angle, the rear wheels can be steered in the same direction as the front wheels, and by operating the steering wheel at a large steering angle, the rear wheels can be steered in the opposite direction to the front wheels. In addition to improving maneuverability when changing lanes through steering operation,
The maneuverability of the vehicle is improved by making the turning radius smaller during U-turns, entering and exiting parking lots, etc. by manipulating the large steering angle of the steering wheel when driving at low speeds.

Then, the eccentric shaft 22 and the joint shaft 30 are slidably connected at the taper engaging portion 37, that is, the male taper member 24 is attached to the eccentric shaft 22 with the balls 23... Female taper member 3
3, 33 are integrated, and male and female tapered surfaces 26,
Rollers 36..., 36... between 34, 26, 34
Because of the interposition, friction can be minimized, and automatic centering can be performed by the centripetal action of the tapered engagement.

Moreover, the joint member that connects and supports the rear wheel tie rods 15, 15 does not swing in the vertical direction.
In other words, the joint shaft 3 moves horizontally only in the left and right direction.
0 to prevent the ball joints 13, 13 from swinging up and down, making it possible to prevent errors in left and right steering angle changes, prevent setting errors in the rear wheel turning angle, and facilitate performance confirmation. can.

Further, such a rear wheel steering system does not require a link mechanism, and the eccentric shaft 22 can be made as short as possible, so that the device can be made compact and the left and right shapes can be symmetrical.

Furthermore, joint shafts 30 with different lengths can be selected according to the suspension model, and ball joints 13, 1
There are no restrictions on the placement of 3.

In addition, since the left and right pipes 43, 43 of the holder 40 have a wide span to support the vehicle body, high rigidity can be obtained even with the use of soft mount rubbers 46, 46, which is effective against sound and vibration isolation. will also be advantageous.

Moreover, the sleeve 50 can be moved back and forth within the front pipe 42 of the holder 40, and the position of the input shaft 20 can be adjusted by the sleeve 50 via the washer 51 and angular ball bearings 28, 29. Since this is held, the engagement relationship can be adjusted. That is, by moving the input shaft 20 backward toward the joint member 30, the initial setting of the engagement state of the tapered engagement portion 37 can be properly performed without clearance while checking the performance. Therefore, the occurrence of hitting sounds can be prevented in advance.

Furthermore, since the assembly and adjustment can be performed in this manner, there is no need for the accuracy control and inspection of each part to be very high.

Furthermore, since the preload spring 52 presses the input shaft 20 backward through the washer 51 and the angular ball bearings 28 and 29, it is possible to constantly prevent the occurrence of play in the tapered engagement portion 37, and the engagement can be maintained even during long-term use. The condition can be maintained in good condition. That is, due to the pressing force of the spring 52, the angular ball bearings 28, 29, 23, 24,
Since the clearance of the tapered engaging portion 37 can be maintained at zero in both the radial and thrust directions, it is possible to prevent rattling between each component and to guarantee the set steering angle.

Next, another embodiment of the adjustment and preload structure will be described with reference to FIG.

A pipe 142 that pivotally supports the input shaft 20 is formed long in the front and back, a roller bearing 156 is interposed between the rear part of the input shaft 20 and the pipe 142, and adjustment means and preload means are configured between the front part of the input shaft 20 and the pipe 142. do.

That is, the front part of the input shaft 20 is formed into a small diameter part 121, the inner ring 124 of the angular ball bearing 123 is press-fitted into the stepped part 122, and the outer ring 125 is formed into a small diameter part 121.
into the large diameter portion 149 at the front of the pipe 142. Then, a thrust washer 151 is applied to the front surface of the outer ring 125, a sleeve 150 is screwed and inserted into the large diameter portion 149 of the pipe, and the rear end of the sleeve 150 is applied to the washer 151. A coil spring 152 is installed in the space between the sleeve 150 and the input shaft 20.
The spring 15 is inserted between the flange 154 provided on the inner periphery of the front part of the sleeve 150 and the washer 151.
Reduce 2. Furthermore, a lockite 155 is screwed onto the sleeve 150. In the figure, 158 is a seal ring.

Such adjustment means and preload means are also included in the present invention.

(Effects of the Invention) As described above, according to the front and rear wheel steering device of the first invention, in particular, the eccentric shaft and the joint member that moves horizontally in the left and right direction are slidably engaged by the tapered engagement portion, By providing an adjustment means to adjust the longitudinal position of the input shaft, it is possible to make the device more compact, eliminate errors in rear wheel steering angle, and apply it to a variety of suspensions, as well as automatically align the eccentric shaft and joint member. It is also possible to combine the input shaft with the joint member, which allows the steering angle to be maintained with high precision.It also allows the use of soft mount rubber, which is advantageous in blocking noise and vibration.Furthermore, it is possible to adjust the assembly between the input shaft and the joint member. It is highly practical, as it allows the initial setting of the tapered engagement portion to be optimized.

Furthermore, in the second invention, since a preload means for biasing the input shaft toward the joint member is provided, the taper engagement portion can always be adjusted properly, preventing play from occurring due to long-term use and guaranteeing the set steering angle. be able to.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a steering angle function generating mechanism of a rear wheel steering system showing the main part of the present invention, and FIG.
A line sectional view, FIG. 3 is a cross-sectional view of a main part showing another embodiment of the adjustment and preload structure, and FIG. 4 is a schematic perspective view of the entire steering device. In the drawing, 1 is a handle, 15 is a rear wheel tie rod, 20 is an input shaft, 22 is an eccentric shaft, 23 is a ball, 24 is a male tapered member, 26 is a male tapered surface, 2
8, 29 and 123 are anguilla bearings, 29
and 125 are outer rings, 30 are joint members, 33 are female tapered members, 34 are female tapered surfaces, 36 are rollers, 37 are tapered engaging portions, 42 and 142 are bearing holders, 50 and 150 are sleeves, 51 and 151 are Thrust washers 52 and 152 are coil springs.

Claims (1)

[Scope of Claims] 1. An input shaft of a rear wheel steering system that rotates in conjunction with a steering wheel. Connects and supports an eccentric shaft provided on a rear wheel and tie rods for the left and right rear wheels, and is capable of horizontal movement in the left and right direction. In a vehicle steering system, the eccentric shaft and the joint member are slidably engaged with a joint member supported on the vehicle body, and the rear wheels are steered along with the front wheels by steering operation of a steering wheel. The front and back parts are configured as tapered engaging parts located on the left and right sides with respect to the eccentric shaft and formed in the vertical direction, and an adjusting means for adjusting the position of the input shaft in the front and back direction is provided. Wheel steering device. 2. In claim 1, the adjustment means includes: an angular bearing interposed between the input shaft and its bearing holder; a sleeve screwed into the bearing holder so that it can move forward and backward; and the sleeve. A front and rear wheel steering device comprising: a thrust washer interposed between outer rings of the bearing; 3. An eccentric shaft installed at the rear end of the input shaft of the rear wheel steering system that rotates in conjunction with the steering wheel and tie rods for the left and right rear wheels are continuously supported and supported by the vehicle body so as to be horizontally movable in the left and right direction. In a vehicle steering device in which a joint member is slidably engaged with the joint member so that both the front wheels and the rear wheels are steered by steering operation of a steering wheel, the engagement portion between the eccentric shaft and the joint member is aligned with respect to the eccentric shaft. The input shaft is configured as a tapered engagement portion located on the left and right sides and formed in the vertical direction, and further provided with an adjustment means for adjusting the position of the input shaft in the front and back direction, and further includes a preload for biasing the input shaft toward the joint member. A steering device for front and rear wheels, characterized in that a means is provided. 4. In claim 3, the adjusting means includes: an angular bearing interposed between the input shaft and its bearing holder; a sleeve screwed into the bearing holder so that it can move forward and backward; and the sleeve. A steering device for front and rear wheels, comprising: a thrust washer interposed between an outer ring of the bearing; and the preload means is a coil spring compressed within the sleeve to press the washer rearward. .