JP2003011842A - Vehicular steering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicular steering device not needing strength increase in a tie rod tube even when an offset between a ball stud and a tube inserting hole is increased. SOLUTION: The vehicular steering device is provided with right and left ball studs connected to tips of right and left tie rod arms and having ball joints, right and left tie rod ends with one ends connected to the right and left ball joints and formed with tube inserting holes offset in a vehicular vertical direction from the ball joints in another end sides, and the tie rod tube with both ends respectively inserted in each tube inserting holes of the right and left tie rod ends. A tie rod tube receiving part in parallel with an axial direction and with a predetermined length and a diameter larger than that of the tube inserting hole is formed in an opening end of the tube inserting hole.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle steering system, and more particularly to a structure of a tie rod end.

[0002]

2. Description of the Related Art In recent years, there has been a tendency for the turning angle of a wheel during steering of a vehicle to increase with the demand for a small turning performance of the vehicle. When steering a wheel, it is necessary to secure a clearance between the front axle and the tie rod for the tie rod that transmits the steering force to the wheel.Therefore, the tie rod is the center of the ball joint connected to the tie rod arm and the tie rod. A design with an offset between the tubes in the vertical direction of the vehicle is adopted.

As a steering mechanism having such a tie rod, for example, those shown in FIGS. 6 and 7 are known.
In the figure, left and right knuckles 2 and 2 are attached to both ends of a front axle 1. These left and right knuckles 2, 2
Is swung by the rotation of the steering arm 3. The base ends of the left and right tie rod arms 4 and 4 are connected to the left and right knuckles 2 and 2.

8 and 9 show the vicinity of one tie rod end. In the figure, the eyeball portion 4A at the tips of the left and right tie rod arms 4 and 4 in FIGS. 6 and 7 and the stud portion 5A at one end of the ball stud 5 are connected by pin coupling. The ball stud 5 is composed of a stud portion 5A on one end side and a ball joint 5B on the other end side that is continuous with the stud portion 5A. The ball joint 5B includes a ball seat portion 6A and a ball portion 6B held in the ball seat portion 6A.

Left and right tie rod ends 6, 6 (only one shown) are connected to the left and right ball joints 5B, 5B (only one shown). The tie rod end 6 is composed of an arm portion 7 and a cylindrical support portion 8 continuous with the arm portion 7. The tie rod end 6 is a rigid body and has a shape that is hard to be deformed even when receiving a force.

The cylindrical support portion 8 has a notched cylindrical portion 9 formed by linearly cutting the tubular body along the axial direction, and the cylindrical portion 9 described above.
Tightening flanges 10, 1 that continuously face the notch tip of the
It is composed of 0 and. The tightening flange portions 10, 10 are tightened with the clamp bolt 11. The cylindrical portion 9 includes a tube insertion hole 12 and the tube insertion hole 12
And a screw hole 13 continuous with the. The tube insertion hole 12 is formed on the other end side of the tie rod end 6, and the axis L of the tube insertion hole 12 is arranged offset from the center of the ball joint 5B in the vehicle vertical direction (dimension H). ).

A tie rod tube 14 is stretched between the left and right tie rod ends 6 and 6. The tie rod tube 14 is a hollow thin-walled steel tube, and has a shape that is easily deformed when subjected to a force. At both ends of the tie rod tube 14, a fitting part 15 having a circular cross section and a screw part 16 having a circular cross section continuous with the fitting part 15 are formed. The fitting portions 15 at both ends of the tie rod tube 14 are fitted into the tube insertion holes 12 of the left and right tie rod ends 6 and 6, and the screw portions 16 at both ends of the tie rod tube 14 are screwed into the screw holes 13 and 13. . As a result, the tie rod tube 14 is connected between the left and right tie rod ends 6 and 6 to form the tie rod 18.

The chamfered portions 17, 17 are provided at the open ends of the left and right tube insertion holes 12, 12 for the purpose of workability and safety.
Are formed respectively.

[0009]

However, the conventional tie rod has the following problems.

As described above, the turning angle of the wheels tends to increase when the wheels are steered due to the requirements for the small turning performance of the vehicle. Since the tie rod tube 14 is arranged immediately behind the front axle 1, as shown in FIGS. 6 and 10, the tie rod tube 14 moves from the neutral state (shown by the solid line) to the front axle 1 when steering the wheels. Approaches the state indicated by the chain double-dashed line. As shown in FIG. 10, when the tie rod tube 14 and the flange portion 1A of the front axle 1 are arranged at the same height, the gap between the front axle 1 and the tie rod tube 14 becomes narrower or interferes when steering the wheels. The possibility arises. In order to avoid this, a design is adopted in which the offset H between the central portion of the ball joint 5B and the tie rod tube 14 is increased (the position where the tie rod tube 14 is arranged is moved away from the front axle 1 in the Y direction of FIG. 10). There is.

As the offset H increases, the bending moment acting on the tie rods 18 increases during steering of the wheels, and the buckling strength and fatigue strength of the tie rods 18 may be insufficient. That is, when the wheel is steered, the tie rod tube 14 bends due to the bending moment,
It is pressed against the open end of the tube insertion hole 12 of the tie rod end 6. Since the tie rod tube 14 is weaker than the tie rod end 6, the tie rod tube 14 is
Stress suddenly changes at the boundary with the opening end of the tube insertion hole 12, and stress concentration occurs. Tie rod tube 1
In No. 4, in order to deal with this stress concentration, it is inevitable to increase the strength by increasing the size, increasing the wall thickness, and increasing the weight. In addition, increasing the size of the tie rod tube 14 may return to the above-described problem that the tie rod tube 14 approaches and interferes with the front axle 1, which is not preferable.

The present invention has been made to solve the above-mentioned problems, and an object thereof is a vehicle in which the strength of a tie rod tube need not be increased even if the offset between the ball stud and the tube insertion hole is increased. Is to provide a steering device.

[0013]

The invention according to claim 1 is
Left and right tie rod arms, tubes connected to the ends of the left and right tie rod arms and having left and right ball studs having ball joints, and one end connected to the left and right ball joints, and a tube offset in the vehicle vertical direction from the ball joints. A steering device for a vehicle, comprising: left and right tie rod ends having insertion holes formed on the other end side; and tie rod tubes having both ends fitted into the respective tube insertion holes of the left and right tie rod ends. A tie rod tube receiving portion having a predetermined diameter along the axial direction and having a diameter larger than that of the tube insertion hole is formed at the open end of the.

According to a second aspect of the present invention, in the tie rod according to the first aspect, the length of the tie rod tube receiving portion in the axial direction is 1 of the diameter of the tube insertion hole.
/ 20 or more. According to a third aspect of the present invention, in the tie rod according to the first or second aspect, the receiving portion for the tie rod tube has a chamfer formed in the middle of the tube insertion hole, and a cross-sectional circle continuous with the chamfer. It is characterized by being configured with an inner peripheral wall portion having a shape.

(Operation) In the inventions of claims 1 to 3, when the wheel is steered, the ball stud and the tube insertion hole are offset in the vehicle vertical direction, so that a bending moment acts on the tie rod end. . This bending moment causes the tie rod tube to bend.

Since a tie rod tube receiving portion having a diameter larger than the diameter of the tube insertion hole and having a predetermined length along the axial direction is formed at the open end of the tube insertion hole, the bent tie rod is Make surface contact with the tie rod tube receiving part of the tube insertion hole of the tie rod end. Therefore, the stress acting on the tie rod tube is dispersed.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

An embodiment of a vehicle steering system according to the present invention will be described with reference to FIGS. 1 and 2. In the embodiment of the present invention, the same components as those of the conventional example are designated by the same reference numerals, and the description thereof will be omitted. Only different components will be described. In the embodiment of the present invention, the tie rod tube receiving portion 22 is formed at the opening end 21 of the tube insertion hole 12.

The tie rod tube receiving portion 22 is formed with a diameter larger than the diameter of the tube insertion hole 12 and along the axial direction (1/20 or more of the diameter of the tube insertion hole 12). Chamfer 2 formed on the
3 and the inner peripheral wall portion 2 having a circular cross section continuous with the chamfered portion 23.
It is composed of 4 and. When the wheel is steered, the center portion of the ball stud 5 and the axis L of the tube insertion hole 12 are offset in the vehicle vertical direction, so that a bending moment acts on the tie rod end 6. Due to this bending moment, the tie rod tube 14 bends (for example, shown by a chain double-dashed line (a) in FIG. 2).

The bent tie rod tube 6 comes into surface contact with the tie rod tube receiving portion 22 and is received by the surface contact portion (b). Therefore, the force applied to the tie rod tube 13 is dispersed, and the stress generated in the tie rod tube 13 is reduced. According to the above configuration,
Even if the offset H accompanying the increase of the turning angle of the wheel is increased, the tie rod tube receiver having a larger diameter than the tube insertion hole 12 and a predetermined length in the axial direction is provided at the opening end 21 of the tube insertion hole 12. Since the portion 22 is formed, the tie rod tube receiving portion 2 of the tie rod tube 14 is formed.
The force received from the inner peripheral wall surface of 2 is dispersed, so that the tie rod tube 14 does not need to be increased in size, thickness, weight and the like to increase strength.

In the embodiment of the present invention, the front axle has been described as an example of the axle, but the present invention is not limited to this, and, for example, in the case of a front and rear wheel steering vehicle, the front axle. ， Applied to rear axle. Further, in the embodiment of the present invention, the shape of the tie rod tube receiving portion has been described with reference to the shape shown in FIG. 2, but the shape is not limited to this, and for example, the shape shown in FIGS. Can be

In FIG. 3, a tie rod tube receiving portion 31 is formed at the opening end 21 of the tube insertion hole 12. The tie rod tube receiving portion 31 is composed of an inner peripheral wall portion 31A having a circular cross section, and has a diameter larger than the diameter of the tube insertion hole 12 and a predetermined length along the axial direction (1/20 or more of the diameter of the tube insertion hole). is there. In FIG. 4, a tie rod tube receiving portion 32 is formed at the open end 21 of the tube insertion hole 12. The tie-rod tube receiving portion 32 has a diameter larger than the diameter of the tube insertion hole 12 and has a predetermined length along the axial direction (1 of the diameter of the tube insertion hole 12).
/ 20 or more), and is formed by a chamfered portion 33 formed in the middle of the tube insertion hole 12 and an inner peripheral wall portion 34 having a circular cross section and a tapered shape which is continuous with the chamfered portion 33.

In FIG. 5, a tie rod tube receiving portion 35 is formed at the opening end 21 of the tube insertion hole 12. The tie rod tube receiving portion 35 includes a tapered inner peripheral wall portion 35A. The inner peripheral wall portion 35A has a predetermined length along the axial direction (1 of the diameter of the tube insertion hole 12).
/ 20 or more) and has a circular cross section. The inner peripheral wall portion 35A rises from the middle portion of the tube insertion hole 12, and the diameter at the tip portion 35B is the tube insertion hole 1
It is larger than the diameter of 2.

[0024]

According to the first to third aspects of the present invention, even if the offset between the ball stud and the tube insertion hole is increased, the diameter of the opening of the tube insertion hole is larger than the diameter of the tube insertion hole. Since the tie rod tube receiving part with a predetermined length along the axial direction is formed, the force received from the tie rod tube receiving part of the tie rod tube can be dispersed, and the tie rod tube can be increased in size, thickness, weight, etc. It has the effect of not increasing the strength.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing the vicinity of a tie rod end of an embodiment of a vehicle steering system of the invention.

FIG. 2 is a cross-sectional view showing the main parts of the steering device of the present embodiment.

FIG. 3 is a first tie rod end according to the present embodiment.
It is an expanded sectional view showing a modification of.

FIG. 4 is a second tie rod end according to the present embodiment.
It is an expanded sectional view showing a modification of.

FIG. 5 is a third tie rod end according to the present embodiment.
It is an expanded sectional view showing a modification of.

FIG. 6 is a plan view showing a conventional steering device for a vehicle.

FIG. 7 is a front view showing a conventional steering device for a vehicle.

FIG. 8 is a cross-sectional view showing the vicinity of a conventional tie rod end.

9 is a cross-sectional view taken along line XX of FIG.

FIG. 10 is an explanatory diagram showing a relationship between a tie rod and a front axle during steering.

[Explanation of symbols]

4 Tie rod arm 5 ball studs 5B ball joint 6 Tie rod end 12 Tube insertion hole 14 Tie rod tube 21 Open end 22 Tie rod tube receiving part

Claims (3)

[Claims] 1. Left and right tie rod arms, left and right ball studs that are connected to the tips of the left and right tie rod arms and have ball joints, and one end is connected to the left and right ball joints. In a steering device for a vehicle, the left and right tie rod ends having tube insertion holes offset in the direction formed on the other end side, and tie rod tubes having both ends respectively inserted into the tube insertion holes of the left and right tie rod ends are provided. A steering device for a vehicle, wherein a tie rod tube receiving portion having a diameter larger than a diameter of the tube insertion hole and having a predetermined length along an axial direction is formed at an opening end of the tube insertion hole. 2. The length of the tie rod tube receiving portion along the axial direction is 1/2 of the diameter of the tube insertion hole.
The tie rod according to claim 1, wherein the tie rod is 0 or more. 3. The receiving portion for the tie rod tube includes a chamfered portion formed in the middle of the tube insertion hole, and an inner peripheral wall portion having a circular cross-section that is continuous with the chamfered portion. The tie rod according to claim 1 or 2.