JP3123396B2 - Variable steering angle ratio steering system for vehicles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable steering angle ratio steering apparatus for a vehicle, and more particularly to a variable steering angle ratio steering apparatus for a vehicle which can change a ratio between a steering operation angle and a steering angle of a steered wheel.

[0002]

2. Description of the Related Art Conventionally, in a vehicle such as an automobile, a ratio of a steering operation angle to a steering wheel turning angle in accordance with a vehicle speed,
That is, a vehicular steering angle ratio variable steering device capable of changing a steering angle ratio is known, and one example thereof is disclosed in JP-A-6-645.
No. 53 discloses this.

As shown in FIG. 10, a vehicular steering angle ratio variable steering device 70 includes a first shaft 74 that is moved in an axial direction in accordance with the rotation of a steering 72, and a first shaft 74 that is moved in the axial direction.
Are arranged substantially in parallel to each other and are moved in the axial direction.
A second shaft 76 for steering the motor 5, a first engaging portion 78 and a second engaging portion 80 rotatably supported by the shafts 74 and 76, respectively, and the first engaging portion 78 And a lever 82 slidably engaged with the second engagement portion 80, respectively.
A fulcrum support member 84 rotatably supporting a fulcrum member 83 located between the first engagement portion 78 and the second engagement portion 80
And a fulcrum position moving mechanism 8 for moving the fulcrum support member 84 in a direction substantially orthogonal to the first shaft 74 and the second shaft 76.
6 is provided. The steering angle ratio is varied according to the vehicle speed. At low speed, the fulcrum support member 84 is connected to the first shaft 74.
Side, the amount of movement of the output shaft 76 with respect to the operation angle of the steering 72 is increased.

[0004]

However, in this vehicle steering angle ratio variable steering apparatus 70, as shown by broken lines S1 (at low speed) and S2 (at high speed) in FIG. The amount of increase in the amount of movement of the output shaft 76 with respect to the amount of increase in the steering angle, that is, the steering angle ratio is constant. For this reason, the steering angle ratio in the vicinity of the neutral position of the steering 72, which is the normal operation range, that is, the steering angle ratio in the small steering angle range W is large in the steering angle range apart from the vicinity of the neutral position of the steering 72, which is the range where the steering is not usually performed much. It becomes the same as the steering angle ratio.

In view of the above, it is an object of the present invention to provide a vehicular steering angle ratio variable steering apparatus capable of suppressing a change in a steering wheel turning angle with respect to a steering operation amount near a steering neutral position. .

[0006]

According to a first aspect of the present invention, there is provided a vehicle steering angle ratio variable steering apparatus according to the present invention, wherein an input shaft that rotates in response to a steering operation and an input shaft that rotates in accordance with the rotation of the input shaft. A pair of moving means, an output shaft connected to the steered wheels, a pair of guide members arranged in parallel with the output shaft, and one end rotatably connected to the pair of moving means and the other end. A pair of first guides guided by the pair of guide members
A connection member, a second connection member having one end rotatably connected to one end of the pair of first connection members, and the other of the pair of first connection members movably engaged along the longitudinal direction;
It is characterized by having a guide portion formed along the longitudinal direction on the second connecting member, and an engaging portion provided on the output shaft and guided by the guide portion.

Therefore, in the present invention, the input shaft rotates in response to the steering operation, and the pair of moving means move along the input shaft by the rotation of the input shaft. When the moving means moves, one end of the pair of first connecting members is guided by the pair of guide members and moves in parallel with the output shaft, and the pair of first connecting members is connected to the pair of moving means. Rotate around. Due to this rotation, the second connecting member rotates around a point connected to one of the first connecting members, and by this rotation, the engaging portion provided on the output shaft becomes a guide formed on the second connecting member. The output shaft moves in the axial direction, and the steered wheels are steered.

According to a second aspect of the present invention, in the vehicle steering angle ratio variable steering apparatus according to the first aspect, the pair of guide members are movable in a direction in which the guide members come into contact with and separate from each other.

Therefore, according to the present invention, when the pair of guide members are moved in a direction in which the pair of guide members move toward and away from each other in accordance with the running state of the vehicle such as the vehicle speed, the second connection with respect to the amount of change in the steering operation angle. The change amount of the rotation angle of the member changes, and the steering angle ratio changes.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a vehicle steering angle ratio variable steering apparatus according to the present invention will be described with reference to FIGS.

As shown in FIG. 1, in a vehicle steering angle ratio variable steering apparatus 10 according to the present embodiment, a steering shaft 12A of a steering wheel 12 is connected to an input shaft by a connecting means such as a gear not shown. The ball screw 14 is connected to the ball screw 14 and operates according to the operation of the steering wheel 12.
Rotate in the direction around the axis (the direction of arrow A in FIG. 1). The output shaft 16 indicated by an imaginary line in FIG. 1 is arranged on the near side of the ball screw 14 in the drawing, in a direction orthogonal to the ball screw 14. The output shaft 16 is movable in the axial direction (the direction of the arrow G in FIG. 1), and left and right steering wheels 18 are connected to both ends of the output shaft 16 via well-known connecting members. .

The ball screw 14 is screwed with ball nuts 20, 22 as a pair of moving means. These ball nuts 20 and 22 are provided at a point P where the ball screw 14 and the output shaft 16 intersect when the vehicle is traveling straight, that is, when the steering wheel 12 is in the neutral position (the state shown in FIGS. 1 and 5).
, And extend in opposite directions along the output shaft 16. When the ball screw 14 rotates, the ball nuts 20 and 22 move in the same direction (the directions of arrows B and C in FIG. 1).

The tip portions 20A of the ball nuts 20, 22
One end of a first arm 28, 30 as a pair of first connecting members is connected to 22A via pins 24, 26, respectively. , 26 in the directions of arrows D and E in FIG. First arm 28, 30
Pins 32 and 34 are provided at the other end of the pair, respectively. These pins 32 and 34 are engaged with grooves 36A and 38A of groove plates 36 and 38 as a pair of guide members. The groove plates 36 and 38 are disposed in parallel with each other with the point P interposed therebetween, and the grooves 36A and 38A are parallel to the output shaft 16, respectively.

Accordingly, when the ball nuts 20, 22 move in the directions of arrows B and C in FIG. 1, the pins 32, 34 move along the grooves 36A, 38A, and the first arms 28, 3A move.
Numerals 0 rotate in the directions of arrows D and E in FIG. 1, respectively. The pin 32 is engaged with a groove 40A formed along the longitudinal direction of the second arm 40 as the second connecting member, and the pin 32 extends along the groove 40A along the longitudinal direction of the second arm 40. It is relatively movable in the direction. One end 40B of the second arm 40 is
The pins 32 and 34 are rotatably supported by the
When moved along A and 38A, the second arm 40 rotates about the pin 34 in the direction of arrow F in FIG.

On the second arm 40, a groove 40C is formed as a guide on the back side (front side in FIG. 1) of the groove 40A, similar to the groove 40A. Output pin 42 is rotatably and slidably engaged. The output pin 42 is connected to the output shaft 16, and when the second arm 40 swings in the direction of arrow F in FIG. 1, the output pin 42 moves in the groove 40A and
6 (in the direction of arrow G in FIG. 1), and the output pin 4
The output shaft 16 connected to the second shaft 2 moves in the direction of arrow G in FIG.

As shown in FIG. 2, the groove plates 36, 3
8 has a rack 4 parallel to the ball screw 14.
4 and 46 are extended, and these racks 44 and 46 are extended.
Is meshed with a pinion 48. In addition, pinion 4
8 is fixed to the rotating shaft 50A of the motor 50.

Accordingly, when the rotating shaft 50A of the motor 50 rotates, the racks 44, 46, that is, the groove plates 36, 38, which are screwed to the pinion 48, move toward and away from each other in response to the rotation (arrows in FIG. 2). H direction). The motor 50 is connected to the control circuit 52. Further, the control circuit 52 is connected to a vehicle speed sensor 54, and the control circuit 52 controls the motor 50 based on a detection value of the vehicle speed sensor 54 and the like.

Next, the operation of the embodiment will be described. In the vehicular steering angle ratio variable steering device 10 of the present embodiment, the ball screw 14 connected to the steering shaft 12A rotates in the direction of arrow A in FIG. Moves in the direction of arrow B or the direction of arrow C in FIG.

For example, as shown in FIG. 3, when the steering wheel 12 is turned to the left and reaches the left turning end, one ball nut 20 reaches a position farthest from the point P, and the other ball nut 22 It reaches the position closest to the point P. Therefore, the first arm 28 rotates about the pin 24 to reach a position parallel to the ball screw 14, and the first arm 30 rotates about the pin 26 to move to a position parallel to the output shaft 16. Reach

As a result, the second arm 40 is
2 moves leftward in FIG. 3 to rotate about the pin 34 to reach a parallel position separated from the ball screw 14 in the leftward direction in FIG. Therefore, the output pin 42 engaged with the groove 40C of the second arm 40 moves leftward in FIG. 3 while sliding in the groove 40C of the second arm 40, and moves to the position farthest from the point P. Reach. That is, the output shaft 16 connected to the output pin 42 moves leftward in FIG. 3 along the axial direction, and the steering wheel 18 (see FIG. 1) connected to the output shaft 16 is turned to the left. Reach the left end position.

On the other hand, as shown in FIG. 4, when the steering wheel 12 is turned to the right and the right turning end is reached, one ball nut 20 reaches a position closest to the point P, and the other ball nut 22 moves to a point It reaches the position farthest from P. Therefore, the first arm 28 rotates about the pin 24 to reach a position parallel to the output shaft 16 and the first arm 30
Rotates about the pin 26 and reaches a position parallel to the ball screw 14.

As a result, the second arm 40 is
4 is rotated about the pin 34 and reaches a parallel position separated from the ball screw 14 to the right in FIG. Therefore, the output pin 42 engaged with the groove 40C of the second arm 40 moves rightward in FIG. 4 while sliding in the groove 40C of the second arm 40, and moves to the position farthest from the point P. Reach. That is, the output shaft 16 connected to the output pin 42 moves rightward in FIG. 4 along the axial direction, and the steered wheels 18 (see FIG. 1) connected to the output shaft 16 are turned right. The right turn end position is reached.

As shown in FIG. 9, the amount of operation of the steering wheel 12, that is, the amount of movement of the output shaft 16 with respect to the steering angle at this time is as shown by a solid line F1, and the small steering angle range W near the neutral position of the steering wheel. , The amount of movement can be suppressed as compared with the conventional movement amount indicated by the broken line S1. That is, in the vehicle steering angle ratio variable steering device 10 according to the present embodiment, the amount of change in the steering angle of the steered wheels with respect to the steering operation amount can be suppressed near the steering neutral position.

In the vehicle steering angle ratio variable steering apparatus 10 according to the present embodiment, the control circuit 52 controls the motor 50 based on the detection value of the vehicle speed sensor 54 and the like. When the rotation shaft 50A of the motor 50 rotates by this control, the racks 44 and 46 screwed to the pinion 48, ie, the groove plate 3
6 and 38 move in a direction in which they come and go (a direction indicated by an arrow H in FIG. 2). When the groove plates 36 and 38 move in the direction in which they come into contact with and separate from each other, as shown in FIGS. 1 and 5, the inclination of the second arm 40 changes at the steering neutral position, and FIGS. As shown in FIG. 8, the swing angle of the second arm 40 with respect to the movement amount of the ball nuts 20 and 22 changes. Due to these changes, the movement amount of the output pin 42 with respect to the operation angle of the steering wheel 12, that is,
The movement amount of the output shaft 16 changes.

Therefore, for example, the motor 50 is controlled by the control circuit 52 and the pinion 48 is rotated to
46, that is, the groove plates 36, 38 are moved in the direction away from each other from the position closest to each other (the position at the time of low speed shown in FIG. 2) as shown in FIG. 7, the inclination of the second arm 40 at the steering neutral position increases, and as shown in FIGS. 7 and 8, the amount of movement of the ball nuts 20 and 22, that is, the second angle with respect to the operation angle of the steering wheel 12, is increased. The swing angle of the arm 40 is reduced.

Therefore, when the vehicle is in a high-speed running state, as shown in FIGS.
8 in the direction away from each other,
By reducing the ratio of the steering angle of the steered wheels 18 to the operation angle of the vehicle, it becomes easier to secure running stability. On the other hand, when the vehicle is running at a low speed, the groove plates 36 and 38 are moved in a direction approaching each other as shown in FIGS. Increasing the ratio facilitates garage entry and the like.

Further, in the vehicular steering angle ratio variable steering apparatus 10 according to the present embodiment, as shown by solid lines F1 and F2 in FIG. 9, the output increases as the steering angle increases right and left around the steering neutral position. The amount of increase in the amount of movement of the shaft 16 is also large. Accordingly, the steering angle ratio is changed from F2 at high speed to F2 at low speed.
In the conventional structure, the change amount Δ1 of the movement amount of the output shaft when changing to 1 is compared with the change amount Δ2 of the movement amount of the output shaft when the steering angle ratio changes from S2 at high speed to S1 at low speed. Small in small steering angle range W. For this reason, in the small steering angle range W, the steering angle ratio can be made substantially constant in all speed ranges from low speed to high speed, and it is possible to reduce discomfort or the like at the time of steering operation due to the change in the steering angle ratio.

In the vehicle steering angle ratio variable steering apparatus 10 of the present embodiment, the steering angle ratio is changed by moving the groove plates 36 and 38 in the direction of coming and going from each other. The 12 neutral positions do not shift. Therefore, it is not necessary to correct the neutral position of the steering wheel 12 and to perform feedback control of the output variation with respect to the steering angle, so that the size of the apparatus can be reduced.

[0029]

According to the first aspect of the present invention, there is provided a vehicle steering angle ratio variable steering apparatus comprising: a pair of input shafts that rotate in accordance with a steering operation; A moving means, an output shaft connected to the steered wheels, a pair of guide members arranged in parallel with the output shaft, one end rotatably connected to the pair of moving means, and the other end guided by the pair of guide members. And a second connection in which one end of the pair of first connection members is rotatably connected to one end, and the other of the pair of first connection members is movably engaged along the longitudinal direction. The structure includes a member, a guide portion formed in the second connecting member along the longitudinal direction, and an engaging portion provided on the output shaft and guided by the guide portion. The change in the turning angle near the steering neutral position An excellent effect of being able to win.

According to a second aspect of the present invention, in the vehicle steering angle ratio variable steering system according to the first aspect, the pair of guide members can be moved in the direction of coming and coming from each other, so that the steering angle ratio can be varied. Further, in the small steering angle range, there is an excellent effect that the steering angle ratio can be made substantially constant in all the speed ranges from low speed to high speed.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a main part of a variable steering angle ratio steering device for a vehicle according to an embodiment of the present invention in a neutral state at a low speed.

FIG. 2 is a schematic configuration diagram showing a low-speed state of a part of the vehicular steering angle ratio variable steering apparatus according to the embodiment of the present invention;

FIG. 3 is a schematic configuration diagram illustrating a left-turn end state of a main part of the variable steering angle ratio steering device for a vehicle according to the embodiment of the present invention at a low speed.

FIG. 4 is a schematic configuration diagram showing a right-turn end state of a main portion of the variable steering angle ratio steering device for a vehicle according to the embodiment of the present invention at a low speed.

FIG. 5 is a schematic configuration diagram illustrating a high-speed neutral state of a main part of the vehicle steering angle ratio variable steering device according to the embodiment of the present invention.

FIG. 6 is a schematic configuration diagram showing a high-speed state of a part of the vehicular steering angle ratio variable steering apparatus according to one embodiment of the present invention;

FIG. 7 is a schematic configuration diagram showing a left turning end state at a high speed of a main part of the vehicle steering angle ratio variable steering device according to the embodiment of the present invention;

FIG. 8 is a schematic configuration diagram showing a right-turn end state at a high speed of a main part of the vehicular steering angle ratio variable steering apparatus according to one embodiment of the present invention.

FIG. 9 is a graph showing a relationship between a steering angle and a movement amount of an output shaft.

FIG. 10 is a perspective view showing a vehicle steering angle ratio variable steering device according to a conventional embodiment.

[Explanation of symbols]

 Reference Signs List 10 steering angle ratio variable steering device for vehicle 12 steering 12A steering shaft 14 ball screw (input shaft) 16 output shaft 18 steered wheel 20 ball nut (moving means) 22 ball nut (moving means) 28 first arm (first connecting member) 30) first arm (first connecting member) 36 groove plate (a pair of guide members) 38 groove plate (a pair of guide members) 40 second arm (second connecting member) 40A groove 40C groove (guide portion) 42 output pin (Engagement part) 44 rack 46 rack 48 pinion

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B62D 6/00-6/10 B62D 3/12 B62D 5/00-5/32 B62D 7/14

Claims (2)

(57) [Claims] 1. An input shaft that rotates in response to a steering operation, a pair of moving means that moves along the input shaft in accordance with the rotation of the input shaft, an output shaft connected to a steered wheel, and the output shaft. A pair of guide members disposed in parallel with each other, a pair of first connecting members one end of which is rotatably connected to the pair of moving means and the other end of which is guided by the pair of guide members; A second connecting member in which one of the first connecting members is rotatably connected, and the other of the pair of first connecting members is movably engaged along the longitudinal direction; And a guide portion formed along the guide shaft, and an engaging portion provided on the output shaft and guided by the guide portion. 2. The variable steering angle ratio steering device for a vehicle according to claim 1, wherein said pair of guide members are movable in a direction of coming and coming from each other.