JP2566715B2 - Steering rod and manufacturing method thereof - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steering rod for converting a rotary motion of a steering shaft into a linear motion and transmitting the linear motion to a tie rod, and a manufacturing method thereof.

[0002]

2. Description of the Related Art FIG. 6 shows a conventional steering rod 1. The steering rod 1 has a rack 2 meshed with a pinion (not shown) that rotates in synchronization with a steering shaft (not shown), and converts the rotational movement of the pinion into a linear movement into a tie rod (not shown). By transmitting it, the wheels are turned. The steering rod 1 is made of carbon steel containing carbon at a predetermined rate to prevent wear, and is heat treated after processing the rack 2.

[0003]

On the other hand, in order to reduce the total weight of the vehicle body, the steering rod 1 is also required to be reduced in weight. For this reason, a long hole 3 along the axial direction is formed in a portion other than the rack 2. . However, since the hole 3 is long, its processing is extremely difficult and the material loss is large. From this, it is considered that a pipe is used as a raw material and a rack is formed on this pipe, but a pipe having a large amount of carbon is not commercially available at least to obtain the strength, and the strength cannot be satisfied. Further, a method is conceivable in which a pipe is formed by using a desired round bar as a raw material, and one end of a heat-treated rack is joined to the end portion of the pipe by means such as welding or screwing, but simply joining by welding. Some of the methods have insufficient bonding strength due to low reliability of welding work, and in the case of the screw-in type, the screws may be loosened.

[0004]

According to the present invention, there is provided a metal hollow shaft having a predetermined length, and a rod-shaped rack forming body which has a rack in a part thereof and is fitted to an end of the hollow shaft. An inner insertion tube portion is formed at an end portion of the rack forming body, a plurality of types of grooves are formed on the outer peripheral surface of the inner insertion tube portion in different directions, and the outer insertion surface is fitted to the outer periphery of the inner insertion tube portion by external pressure. An extrapolation tube portion that is bitten into the groove by deformation is formed at the end of the hollow shaft.

[0005]

According to the present invention, the outer insertion tube portion fitted to the outer circumference of the inner insertion tube portion is deformed by the external pressure, and the inner peripheral surface of the outer insertion tube portion is cut into the groove of the inner insertion tube portion. by different directions, the relative axial and rotational movement between the inner intubation portion and the outer cannula portion can be reliably secured, thereto
The length of the member connected to the rod-shaped rack forming body
Can be made of metal hollow shaft, and therefore special
Lightweight steering rod with a hollow shaft that does not require machining
In addition, it is possible to easily connect the insertion tube portion and the insertion tube portion by a method of applying pressure from the outside of the insertion tube portion fitted to the outer circumference of the insertion tube portion.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in the order of manufacturing steps with reference to FIGS. First, as shown in FIG. 3A, a commercially available iron hollow shaft (pipe) 4 and a rack forming body 5 are provided.
And prepare. An outer insertion tube portion 6 having a desired inner diameter is formed at the end of the hollow shaft 4. Rack forming body 5
Is formed by a round bar made of carbon steel, a rack 7 is formed in the middle of the rod, and an insertion tube 8 is formed at the end of the rod 7. A plurality of annular grooves 9 and spiral grooves 10 are formed as seed grooves. The formation of the annular groove 9 and the spiral groove 10 will be described in detail later. Then, the rack forming body 5 is cured by heat treatment. In this state, the outer diameter dimension of the inner insertion tube portion 8 matches the inner diameter dimension of the outer insertion tube portion 6.

Next, as shown in FIG. 3B, a die 11 and a punch 12 are prepared. The die 11 has a through hole 13 that matches the outer diameter dimensions of the hollow shaft 4, the rack forming body 5 and the punch 12, and an inner diameter that is located at the end of the through hole 13 and that is slightly smaller than the inner diameter of the through hole 13. Small-diameter hole 14 and step 1
It is formed with 5 as the border. The step portion 15 is formed so as to be steeply tapered.

Next, as shown in FIG. 3B, the die 1
Insert the hollow shaft 4 and the rack forming body 5 into the through hole 13 of 1,
The rear end of the rack forming body 5 is pressed by the punch 12. At this time, the tip end of the hollow shaft 4 is in contact with the step portion 15 and the outer periphery is pressed against the inner wall of the through hole 13 of the die 11, so that the inner peripheral surface side is plastically deformed inward. Due to this plastic deformation, the inner peripheral surface of the outer insertion tube portion 6 bites into the annular groove 9 and the spiral groove 10. Further, since the tip of the hollow shaft 4 is narrowed to the step portion 15 of the die 11, chamfering is performed at the same time.

Thereafter, the hollow shaft 4 and the rack forming body 5 are taken out from the die 11 to form the steering rod 16 as shown in FIG. FIG. 2 is a vertical cross-sectional side view showing a state in which the outer cannula portion 6 is plastically deformed. In this state, if the spiral groove 10 alone is considered, the movement in the axial direction while rotating with respect to the hollow shaft 4 is allowed, and if only the annular groove 9 is considered, the axial movement relative to the hollow shaft 4 is prevented. Although the movement in the rotation direction is allowed even if it is performed, the two types of annular groove 9
Since the direction of the spiral groove 10 is different from that of the spiral groove 10, movement of the rack forming body 5 with respect to the hollow shaft 4 in the axial direction and the rotation direction is reliably prevented. That is, the hollow shaft 4 and the rack forming body 5 can be firmly bonded to each other.

Further, since the hollow shaft 4 does not need to form the rack 7 on its own, it is not necessary to obtain a particularly high strength. Therefore, the cost can be reduced by using an inexpensive commercially available pipe as the hollow shaft 4. You can

Before the rack forming body 5 is inserted into the hollow shaft 4, a brazing brazing wire is housed in the end of the hollow shaft 4, and the inner peripheral surface of the outer insertion tube portion 6 is surrounded by an annular groove 9 and a spiral groove 10. After digging into and, the wax is melted by high-frequency heat or the like to form an annular groove 9
Further, the bonding strength between the hollow shaft 4 and the rack forming body 5 can be further increased by infiltrating into the gap between the spiral groove 10 and the inner peripheral surface of the outer insertion tube portion 6 by the capillary phenomenon. The same purpose can be achieved by adding welding work instead of brazing.

Although the annular groove 9 and the spiral groove 10 are formed in the rack forming body 5 by cutting or rolling, in the present embodiment, they are formed by rolling. Hereinafter, processing by rolling will be described. FIG. 4A shows the rolling machine 1.
7 is a plan view, and FIG. 4B is a front view showing the rolling machine 17. In the fixed part 18 and the movable part 19 of the rolling machine 17,
A headstock 21 and an auxiliary headstock 22 that rotatably support a main shaft 20 driven by a motor (not shown) are provided. Each main shaft 20 has a rolling roller 23,
24 is fixedly fitted. Rolling rollers 23, 24
Are separately formed and then joined. A support blade 25 is provided between the fixed portion 18 and the movable portion 19.

Therefore, the insertion tube portion 8 of the rack forming body 5 is placed on the support blade 25, the movable portion 19 is moved to the fixed portion 18 side while rotating the main shaft 20 in one direction, and the fixed portion 1
When the insertion tube part 8 is sandwiched between the rolling rollers 23 and 24 on the 8 side and the rolling rollers 23 and 24 on the movable part 19 side, the rolling roller 23 forms the annular groove 9, and the rolling roller 24 The spiral groove 10 is formed.

In the above-mentioned embodiment, the plural kinds of grooves having different directions have been described as the annular groove 9 and the spiral groove 10 along the circumferential direction, but another example of the groove having a different direction from the spiral groove 10 is shown in FIG. It will be described based on. FIG. 5A shows the rack forming body 5 in which a plurality of grooves 26 are formed in a spline shape along the axial direction. 5 (b) and 5 (c) show a plurality of grooves 27 or 28 along the axial direction formed in the rack forming body 5 by cutting.

Therefore, since the grooves 26, 27, 28 are formed parallel to the axial direction of the rack forming body 5, when the grooves 26, 27, 28 are made to bite into the inner circumference of the outer insertion tube portion 6, Movement in the direction of rotation is blocked. Therefore, the movement of the spiral groove 10 in the rotational direction and the axial movement associated therewith are reliably prevented. Further, although not shown, the same purpose can be achieved by forming a spiral groove 10 and a spiral groove inclined in a direction different from the inclination direction of the spiral groove 10 in the insertion tube portion 8.

[0016]

According to the present invention, a metal hollow shaft having a predetermined length and a plurality of metal end shafts having a closing portion and a mechanism portion for closing both end surfaces of the hollow shaft are provided. The inner tube is formed on both ends of the shaft or the hollow shaft, and plural kinds of grooves are formed on the outer peripheral surface of the inner tube in different directions, and the inner tube is fitted to the outer circumference of the inner tube and deformed by external pressure. Since the outer insertion pipe part that is bite into the groove is formed at both ends or the end shaft of the hollow shaft, the outer insertion pipe part fitted to the outer circumference of the inner insertion pipe part is deformed by external pressure, and the inner circumference of the outer insertion pipe part Although the surface digs into the groove of the insertion tube part, the relative axial movement and rotation direction movement of the insertion tube part and the outer insertion tube part can be reliably fixed by the different direction of the grooves. ,this
The member connected to the rod-shaped rack forming body can be
Can be a hollow shaft made of metal and therefore special
With a hollow shaft that does not require special processing, a lightweight steering lock
Can be obtained de, also Ki de easily be coupled to the inner intubation portion and the outer cannulated portion in a manner to pressurize the outer cannula portion outside fitted to the outer periphery of the inner cannula portion, is La, hollow Since the shaft does not need to form a rack on its own, it is not necessary to obtain a particularly high strength, and this has the effect that the cost can be reduced by using an inexpensive commercially available pipe.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional front view showing a steering rod according to an embodiment of the present invention.

FIG. 2 is a vertical sectional front view of a main part.

FIG. 3 is a vertical sectional front view showing a manufacturing process of the steering rod.

FIG. 4 is a view showing a state in which a groove is formed in an inner tube,
(A) is a plan view and (b) is a front view.

FIG. 5 is a vertical side view showing another example of the groove.

FIG. 6 is a vertical sectional front view showing a conventional example.

[Explanation of symbols]

 4 Hollow shaft 5 Rack forming body 6 External insertion pipe part 7 Rack 8 Internal insertion pipe part 9-10 groove 26-28 groove

Claims (2)

(57) [Claims] 1. A metal-made hollow shaft having a predetermined length, and a rod-shaped rack forming body having a rack partially fitted into the end of the hollow shaft are provided, and the end of the rack forming body is provided. An inner insertion tube portion is formed on the outer peripheral surface of the inner insertion tube portion, and a plurality of types of grooves extending in different directions are formed on the outer peripheral surface of the inner insertion tube portion. A steering rod, wherein an extrapolation tube portion is formed at an end of the hollow shaft. 2. A metal hollow shaft having a predetermined length and a rod-shaped rack forming body having a rack formed in a part thereof are provided, and an insertion tube portion is formed at an end of the rack forming body. A plurality of types of grooves are formed on the outer peripheral surface of the intubation portion in different directions, and an outer insertion tube portion fitted to the outer periphery of the inner insertion tube portion is formed at the end of the hollow shaft. A method of manufacturing a steering rod, characterized in that after inserting the inner insertion tube portion into the groove, the outer insertion tube portion is deformed inward by an external pressure so that the inner circumference of the outer insertion tube portion is bitten into the groove. .