JPH035352B2 - - 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) The present applicant proposed Japanese Patent Application No. 127188/1983 (Japanese Patent Application No. 30869/1983) as one of the four-wheel steering systems for vehicles. This steering system involves slidably engaging 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 a joint member that connects and supports the tie rods for the left and right rear wheels. , the joint member can only be moved in the left-right direction.

(Problems to be Solved by the Invention) According to such a steering system, since the eccentric shaft is directly engaged with the joint member, precision is required for alignment.
In particular, there is a technical problem in that it is difficult to avoid the occurrence of clearance in the radial direction at the engaging portion.

The present invention has been made to solve the technical problems in both the above-mentioned steering systems, and its purpose is to:
The front and rear wheels are designed to realize automatic centering between the eccentric shaft and the joint member, prevent clearance from occurring at the engagement portion between the eccentric shaft and the joint member, and further prevent rearward deflection of the joint member. To provide steering equipment.

(Means for Solving the Problems) Therefore, the present invention provides an eccentric shaft 2 provided at the rear end of an input shaft 20 of a rear wheel steering system that rotates in conjunction with a steering wheel.
2 and a joint member 40 that connects and supports the left and right 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. , a preload means 6 that engages the eccentric shaft 22 and the joint member 40 at a tapered engagement portion 47 and urges the input shaft 20 in the direction of the joint member 40.
2,162, and further the joint member 40
It is characterized in that a regulating means 87 is provided at the rear of the central portion.

Specifically, the regulating means 87 includes a guide member 80 disposed between the joint member 40 and its holder 50, and a roller 85 whose axis is horizontal, which is interposed between the guide member and the joint member.
It consists of adjustment bolts 83, 83 that press against a guide member that is screwed into the holder from the rear.

(Function) Since the eccentric shaft 22 and the joint member 40 are slidably engaged with each other at the taper engaging portion 47 in this way, automatic centering can be performed by the centripetal action of the tapered engaging portion 47, and the input shaft 20 Since the preload means 62 and 162 are provided to bias the joint member 40, the engagement state of the tapered engaging portion 47 can be maintained properly at all times by the pressing force thereof. 87, it is possible to prevent the joint member 40 from deflecting rearward due to the pressing force of the preload means 62, 162, thereby improving responsiveness.

(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. 7 are schematic perspective views of the entire steering system.

As shown in Fig. 7, the support shaft 2 of the handle 1 is built into a gearbox 3 of the rack pinion type, and tie rods 5, 5 are connected to both ends of the rack shaft 4, and the tie rods 5, 5 support the front wheels 7, 7. The knuckle arms 6, 6 are connected to each other, and as is known, the front wheels 7, 7 are connected to each other.
is steered in the steering direction of the steering wheel 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 on the rear wheel of this input shaft 20, and an eccentric shaft 22 is provided to protrude from this flange 21. The base of this eccentric shaft 22 is formed into a male tapered portion 23 .

On the eccentric shaft 22, a pinion 31 is mounted at the front.
A cylindrical member 30 integrally provided with a circular eccentric cam 32 at the rear thereof is rotatably fitted thereinto. That is, the inner periphery of the pinion 31 of the cylindrical member 30 is formed into a female tapered member 33,
Balls 24 are interposed between the male taper portion 23 to form an angular bearing, and rollers 25 are interposed between the inner periphery of the eccentric cam 32 and the tip of the eccentric shaft 22. do.

On the other hand, as shown in FIG. 7, 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 40 via ball joints 14, 14, respectively. As shown in FIG. 1, an engaged member 41 is fixedly provided at the center of the joint shaft 40. As shown in FIG. That is, the engaged member 41 is fixedly integrated with the center of the joint shaft 40 from the rear lower part using two bolts 49, 49 as shown in FIG. Female tapered portions 44, 44 facing forward are formed on opposing surfaces of the vertical wall portions 43, 43.

Then, an engaging member 36 is mounted on the eccentric cam 32 with balls 35 interposed therebetween, and the eccentric cam 32 is provided with a contact type angular bearing.
Male tapered surfaces 38, 38 facing rearward are formed on the side surfaces of the left and right vertical wall portions 37, 37 of this engaging member 36. Stopper protrusions 39, 39, 39, 39 protrude from the upper and lower ends of the male and female tapered surfaces 38, 38.

Furthermore, when the engaging member 36 and the engaged member 41 are engaged and assembled, both the left and right tapered surfaces 38, 44, 3
As shown in Fig. 3 between 8 and 44, the retainer 4
Rollers 46 . . . , 46 .

The above input shaft 20 and joint shaft 40 are connected to a box 51 at the center, and pipes 5 at the front, rear, left and right sides.
It is supported by a holder 50 integrally formed with 2, 53, and 53. That is, with the engaged member 41 facing inside the box 51 of the holder 50, the joint shaft 40 is inserted into the left and right pipes 53, 53 with metal bearings 54, 5.
4, it is pivoted so that it can slide horizontally from side to side. Then, with the eccentric shaft 22 facing inside the box 51, the engaging member 3
6 to the engaged member 41, the rollers 46..., 46
. . . to connect the input shaft 20 to the front pipe 5.
It is rotatably supported within 2.

Furthermore, an internal ring gear 70 is provided in the inner part of the box 51 when viewed from the rear, and the pinion 31 meshes with the internal ring gear 70 and the thrust is restricted by a snap ring 79. This ring gear 70 consists of two ring gears 71 and 72 stacked in the axial direction,
One gear 71 is unrotatably fixed to the box 51 with a bolt 78, and upper and lower stepped portions 73, 73 are formed on one side of the other gear 72, and are screwed together from the top and bottom of the box 51 for adjustment. The bolts 77, 77 are applied to the stepped portions 73, 73. Also, both ring gears 71,
A large number (six in FIG. 4) of recesses 74 are provided on the outer circumference of the recess 72 that penetrate in the axial direction.
An S-shaped spring 75 as shown in FIG. 5 is compressed in the circumferential direction to preload the rotatable gear 72.

Specifically, the input shaft 20 is supported by installing a ring 27 with balls 26 interposed on the front part of the flange 21 at the rear end, a contact type angular bearing, and connecting the ring 27 to the pipe 52. Fits lightly into the inner periphery of the proximal end. Then, a thrust washer 61 is applied to the front end of the ring 2, a sleeve 60 is screwed and inserted into the pipe 52, and the rear end of the sleeve 60 is abutted against the washer 61. A space is provided between the sleeve 60 and the input shaft 20, a coil spring 62 is inserted into this space, and the spring 62 is compressed between the washer 61 and the seat 64 which is regulated by a step 63 at the middle part of the inner circumference of the sleeve 60. The ring 27 is preloaded to urge the ring 27 rearward. Furthermore, a lock nut 65 is screwed onto the sleeve 60. Further, a roller bearing 66 is interposed between the front end of the sleeve 60 and the input shaft 20, and a seal cap 67 is mounted on the roller bearing 66.

In the above, a vertical surface 47 is formed on the rear surface of the engaged member 41, as shown in FIG. A guide groove 57 is formed in the left-right direction in the boss 56, and a vertical surface 81 facing the vertical surface 47 is formed in the groove 57.
A guide bar 80 is inserted. This vertical surface 8
Stopper protrusions 82, 82 protrude from the left and right ends of 1. Two adjustment bolts 83, 8 on the left and right screw the guide bar 80 into the cover 55 from behind.
A roller 85 . . . whose axis is perpendicular is interposed between both vertical surfaces 47 and 81 and held by a retainer 84 . Also guide bar 80
A plate spring 86 is interposed between the guide bar 80 and the cover 55, and preloads the guide bar 80 so as to always urge it forward.

In this way, the holder 50 is arranged with the input shaft 20 aligned with the left and right center line of the vehicle body, and the left and right pipes 5
3 and 53 are supported on vehicle body side brackets 92 and 92 with soft mount rubbers 91 and 9 interposed therebetween.
The left and right ball joints 14, 14 are covered with compact rubber boots 94, 94 tightened with bands on the ends of the pipe 53 and the tie rod 15, respectively.

The settings of the above-mentioned 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 3. Here, the pinion 31 is the fourth
As shown in the figure, the eccentric cam 32 meshes with the lowest part of the internal ring gear 70, and the top part 34 of the eccentric cam 32 faces vertically downward as shown in FIG.

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. When the eccentric shaft 22 rotates as a crank, the pinion 31 of the cylindrical member 30 rotatably fitted onto the eccentric shaft 22 moves toward the box 5.
By meshing with the internal ring gear 70 provided in 1, it revolves inside this ring gear 70 and rotates on the eccentric shaft 22. Since the cylindrical member 30 integrally includes a pinion 31 and an eccentric cam 32, the eccentric cam 32 also performs the same revolution and rotation as the pinion 31.

The combined movement of the eccentric cam 32 due to this revolution and rotation is caused by an engaging member 36 provided on the eccentric cam 32 via a ball 35..., and a movement via rollers 46..., 46... on both left and right sides of the eccentric cam 32, respectively. This is converted into a left-right direction movement of the engaged member 41 which is engaged by sliding up and down. That is, the joint shaft 40 to which the engaged member 41 is fixed moves in the left-right direction,
Rear wheel tie rods 15, 1 connected to both ends of the rear wheel tie rods 15, 1
5 moves in the left-right direction, and the rear wheels 17, 17 are steered.

Specifically, due to the above-mentioned initial setting, until the revolution angle of the pinion 31 due to crank rotation from the initial position of the eccentric shaft 22 is less than a predetermined angle, the rear wheel 1
7 and 17 are steered in the same direction as the front wheels 7 and 7, that is, in the small steering angle operation range of the steering wheel 1, the front and rear wheels are steered in the same phase. When the revolution angle of the pinion 31 reaches a predetermined angle, the steering angle of the rear wheels 17, 17 becomes zero. When the revolution angle of the pinion 31 exceeds a predetermined angle, the rear wheels 17, 17 are steered in the opposite direction to the front wheels 7, 7. In other words, in the large steering angle operation range of the handle 1, the front and rear wheels are steered in opposite phases. It has become something that is done.

Next, the maximum steering angle of the rear wheels when the front and rear wheels are steered in the same phase and when the wheels are steered in opposite phases will be explained.

First, the rotation direction of the pinion 31 due to crank rotation from the initial position of the eccentric shaft 22 is opposite to the rotation direction of the eccentric shaft 22 when the revolution angle is less than a predetermined angle.
Since the movement direction in the left-right direction is opposite to that of the top portion 34 of No. 2, the resultant displacement amount that is the difference therebetween is small. Therefore, since the maximum horizontal displacement of the joint shaft 40 that engages with the eccentric cam 32 is small, the rear wheels 17, 17
The maximum steering angle when the vehicle is steered in the same direction as the front wheels 7, 7 is small.

Furthermore, when the revolution angle of the pinion 31 exceeds a predetermined angle, the eccentric shaft 22 and the eccentric cam 3 relative to the input shaft 20
2 and the top 34 of the rear wheels 17 and 17, the combined displacement becomes larger with the positive and negative signs being reversed. Since the maximum displacement of the joint shaft 40 is large, the rear wheels 17 The maximum steering angle in the direction opposite to that of the front wheels 7, 7 becomes larger.

In this way, the maximum steering angle of the rear wheels in the same direction as the front wheels, which is achieved by operating the steering wheel at a large steering angle, is greater than the maximum steering angle of the rear wheels in the opposite direction to the front wheels, which is achieved by operating the steering wheel at a large steering angle. This allows for better maneuverability when changing lanes by operating a small steering angle of the steering wheel while driving at high speeds, and improves maneuverability when driving at low speeds such as making U-turns or parking lots by operating a large steering angle of the steering wheel. By making the turning radius smaller when entering and exiting the vehicle, the maneuverability of the vehicle can be further improved.

Then, the eccentric cam 32 and the joint shaft 40 are slidably engaged with each other at the tapered engaging portion 47, that is, the eccentric cam 32
A male taper member 36 is attached to the joint shaft 40 by interposing a ball 35 .
Rollers 46..., 46 between 8, 44, 38, 44
Because of the interposition of..., friction can be minimized, and automatic centering can be performed by the centripetal action of the taper engagement.

Furthermore, the sleeve 60 can be moved back and forth within the front pipe 52 of the holder 50, and the position of the input shaft 20 can be adjusted by the sleeve 60 via the washer 61 and the angular ball bearings 26, 27. Since this is held, the engagement relationship can be adjusted.

Furthermore, since the preload spring 62 presses the input shaft 20 backward through the washer 61 and the angular ball bearings 26 and 27, it is possible to prevent the taper engagement portion 47 from rattling, and maintain its engaged state even during long-term use. can be maintained in good condition. That is, due to the pressing force of the spring 62, the angular ball bearings 26, 27, 24, 30, 3
5, 36, since the clearance of the tapered engaging portion 47 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.

In the above, a regulating means 87 is provided at the rear of the center of the joint shaft 40, that is, a guide bar 80 is provided at the rear of the center of the joint shaft 40, and rollers 85 are interposed between this and the joint shaft 40,
Since the joint shaft 40 is biased forward by the elastic force of the plate spring 86, backward deflection of the joint shaft 40 due to the bias of the preload spring 62 can be prevented.
0 sliding friction can also be reduced, and responsiveness can be improved. Further, even if the span of the metal bearings 54, 54 that pivotally support the joint shaft 40 is widened, the rigidity of the joint shaft 40 can be ensured, and wear of the metal bearings 54, 54 can be prevented.

Next, another embodiment of the adjustment and preload structure of the input shaft 20 will be described based on FIG. 6.

A pipe 152 that pivotally supports the input shaft 20 is formed long in the front, a roller bearing 166 is interposed between the rear part of the input shaft 20 and the pipe 152, and adjustment means and preload means are configured between the front part of the input shaft 20 and the pipe 152. do.

That is, the front part of the input shaft 20 is formed into a small 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 part 121.
and fit lightly into the large diameter portion 159 at the front of the pipe 152. Then, a thrust washer 161 is applied to the front surface of the outer ring 125, a sleeve 160 is screwed and inserted into the large diameter portion of the pipe 159, and the rear end of the sleeve 160 is abutted against the washer 161. A coil spring 162 is installed in the space between the sleeve 161 and the input shaft 20.
The spring 16 is inserted between the flange 164 provided on the inner periphery of the front part of the sleeve 160 and the washer 161.
Reduce 2. Furthermore, a lock nut 165 is screwed onto the sleeve 160.

In addition, in the embodiment, a so-called asymmetric function type steering device was described in which the maximum steering angle of the rear wheels is larger when the front wheels are out of phase than when they are in the same phase. The present invention also includes a steering system with a symmetric function that is made to match.

(Effects of the Invention) As described above, according to the front and rear wheel steering device of the present 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, and input Since a preload means is provided to bias the shaft toward the joint member, and a regulating means is provided to prevent rearward deflection at the center of the joint member, automatic centering of the eccentric shaft and the joint member can be performed. , the rudder angle can be maintained with high precision,
Moreover, it is possible to always optimize the taper engagement part, prevent the occurrence of backlash due to long-term use, and guarantee the set steering angle.In addition, it is possible to ensure the rigidity of the joint member and improve responsiveness. It is highly practical as it also makes it possible to reduce the sliding friction of the joint member.

[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.
3 is a sectional view taken along the line in FIG. 1, FIG. 4 is a sectional view taken along the line in FIG. FIG. 7 is a sectional view of a main part showing another embodiment, and a schematic perspective view of the entire steering device. In the drawing, 1 is a handle, 15 is a tie rod for the rear wheel, 20 is an input shaft, 22 is an eccentric shaft, 30 is a cylindrical member, 31 is a pinion, 32 is an eccentric cam, 35 is a ball, 36 is a male taper member, 38 is a male tapered surface,
40 is a joint member, 43 is a female taper member, 4
4 is a female tapered surface, 46 is a roller, 47 is a tapered engagement part, 62, 162 is a preload means, 70 is an internal gear, 80 is a guide member, 83 is an adjustment bolt, 85 is a roller, 86 is a plate spring,
87 is a regulating means.

Claims (1)

[Scope of Claims] 1. An eccentric shaft provided at the rear end of the input shaft of the rear wheel steering system that rotates in conjunction with the steering wheel connects and supports the left and right rear wheel tie rods, and is movable horizontally 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 eccentric shaft and the joint member are engaged with each other in a tapered manner. A preload means is provided that engages at the mating portion and urges the input shaft toward the joint member, and further a restricting means is provided at the rear of the central portion of the joint member to prevent the joint member from deflecting rearward. A front and rear wheel steering device characterized by: 2. In claim 1, the regulating means includes: a guide member disposed between the joint member and its holder; and a roller whose axis is perpendicular, interposed between the guide member and the joint member; A front and rear wheel steering device comprising an adjustment bolt that is screwed into the holder from the rear and pressed against the guide member.