JPH07323846A - Jacket tube of steering column and its manufacture - Google Patents

Abstract

PURPOSE:To provide the jacket tube of 8 vehicle steering column and its manufacture which does not require the lathe-cutting of a pipe inner diameter, the pressure entry of a ring and the stopping of its coming-off. CONSTITUTION:A ring 5 is fitted to the end portion of a mandrel 1, and the mandrel 1 is inserted into a pipe 2 whose diameter is larger than the ring 3, and the throttle processing of the end portion of the pipe 2 is conducted toward the ring 3 at a predetermined lengthy and the coming-off stop of the ring 3 is conducted at the step difference portion of the radially pipe 2 circulating radially into both the axial end portion sides of the ring 3, and tight coupling is conducted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle steering column jacket tube and a method of manufacturing the same.

[0002]

2. Description of the Related Art Steering columns in automobiles are
A steering shaft for transmitting steering torque of a steering wheel to a gear box to steer steering wheels is rotatably inserted into a jacket tube fixed to a vehicle body. That is, bearings are fixed to both ends of the jacket tube and are pierced through and supported by the steering shaft, whereby the steering shaft is rotatably supported about the axis.

Incidentally, it is customary to employ a structure in which the jacket tube is axially contracted by being divided in two in the axial direction and fitted to each other with a predetermined tightening force. Therefore, in accordance with this, the steering shaft is also bisected in the axial direction and contracted in the axial direction. Further, a clamp having a structure in which the jacket tube is detached from the vehicle body due to a load of an occupant colliding with the steering wheel is often used for connecting the jacket tube and the vehicle body.

By adopting such a contraction structure, when an occupant collides with the steering wheel during a vehicle collision,
By contracting the steering column in the axial direction, it is possible to absorb the impact load applied to the occupant.

In the manufacture of this type of steering column, conventionally, as shown in FIG. 4, the inner diameter surface of the end portion of the pipe 14 having a predetermined diameter is turned by a predetermined length in the radial direction and the axial direction,
Forming an inner diameter surface 16 approximately equal to the axial length L and outer diameter D ₂ of the bearing 15 to press-fit the bearing 15 from the end and bend the outermost end in the radial direction to prevent the bearing from coming off. Met. In the vicinity of the end of the pipe 14, a pipe having a predetermined diameter is used as the drawing portion 17 so that the end has a small diameter.

[0006]

However, according to the conventional steering column described above, turning the inner diameter surface of the pipe 14 in order to fit the bearing 15 is not possible.
Precision is strict in relation to the press-fitting margin, surface roughness is also required, and since the turned part has a thin wall, it is necessary to use a thick pipe, and turning scraps generate work environment. There are drawbacks such as worsening.

In addition, press-fitting the bearing 15 into the pipe 14 requires controlling the press-fitting force, and also causes an inclination between the axis C of the pipe 14 and the axis C ₁ of the bearing 15. In addition, there is a drawback that there is a high possibility that variations will occur between the inner diameter accuracy of the press-fitting margin and the outer diameter accuracy of the bearing.

Further, the bearing retainer is caulked at 6 to 8 places in the circumferential direction of the bearing, or by roll caulking such that the entire circumference of the pipe end is bent in the central direction orthogonal to the axis. The caulking has a polygonal shape and deteriorates in quality, and the roll caulking has disadvantages such as the need to process the entire circumference using a roll, which requires time, and is inefficient, resulting in high cost.

In order to solve the above-mentioned drawbacks, the present invention provides a jacket tube and a method for manufacturing the same, which does not require turning of the inner diameter of the pipe, press fitting of the ring, and retaining of the ring.

[0010]

In a jacket tube for a steering column according to the present invention, a bearing which is internally fitted to an end portion of a pipe is formed by drawing one end portion of the pipe and radially extending to both axial end portions of the bearing. It is characterized in that it is secured by a stepped portion formed by wrapping around and is tightened.

Further, the manufacturing method of the steering column is as follows.
A ring is fitted to the end of the mandrel, the mandrel is inserted into a pipe having a larger diameter than the ring, and the pipe end is drawn toward the ring at a predetermined length, It is characterized in that a step portion of the pipe formed so as to wrap around in the radial direction is formed on both end sides in the axial direction to prevent the ring from coming off and to tighten it.

[0012]

The present invention is an application of the fact that when the pipe is drawn, the diameter of the pipe that is drawn is smaller than the diameter of the die depending on the drawing angle. Therefore, since the ring is fastened by forming a step on both axial end portions by drawing the pipe, it is not necessary to perform turning of the pipe, press fitting of the ring, and retaining thereof.

This method can be applied not only to a simple ring such as a collar but also to fitting a bearing into a pipe, and can be established as a method for internally fitting a small diameter ring at the end of the pipe. Therefore, if it is applied to the production of a jacket tube for a steering column, it will greatly reduce the number of steps and reduce the cost.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the illustrated embodiments. FIG. 1 shows an example in which the present invention is applied to a jacket tube of a steering column, in which a bearing 12 is fastened to a tapered end portion 11 of a pipe 2 by step portions 9 and 10 and fitted therein. Needless to say, the bearing 12 rotatably supports the steering shaft 13 about its axis.

The manufacturing process of this jacket tube will be described. As shown in FIGS. 2 and 3, a pipe 2 is inserted into a mandrel 1 to fix one end thereof, and a ring 3 such as a bearing is attached to the end of the mandrel 1. Fitting orthogonally, the ring 3 faces the other end of the pipe 2. The other end of the pipe 2 is arranged so as to slightly protrude from the ring 3, and is bent in the direction of the center of the ring 3 so as to form a retaining member.
In addition, a ring-shaped pedestal 4 is fitted to the mandrel 1 near the end of drawing.

The ring 3 has a diameter smaller than the inner diameter of the pipe 2, and therefore, in order to fasten the ring 3 with the pipe 2, a drawing die 5 is used. This drawing die 5
As shown in FIGS. 2 and 3, is a hole having a head portion 6, a throttle portion 7 following the head portion 6 at a predetermined throttle angle α, and a ring holding portion 8 following the head portion 6, and whether or not it rotates about its axis. ,
Alternatively, the drawing die 5 is fixed and the mandrel 1 is inserted into the hole of the drawing die 5 while rotating the mandrel 1 about the axis thereof.

Therefore, when the mandrel 1 is moved toward the drawing die 5 while rotating either or both of the mandrel 1 and the drawing die 5, the end of the pipe 2 is radiused by the head 6 at the radius of the ring 3. While being bent in the direction, the drawing part 7 draws, and the ring holding part 8 presses the ring 3, so that, as shown in FIGS. The ring 3 is prevented from coming off and the ring 3 is tightened at the step portions 9 and 10 formed by wrapping around.

That is, in the step portions 9 and 10, the diameter D _{1 of the} pipe 2 is smaller than the diameter D _{1 of the} drawing die 5 by the drawing angle α when the pipe 2 is drawn (for example, 0.2 to 0). 0.5 mm) is applied.
If the radius of the rounded portion formed on the peripheral portion of the end surface of the ring 3 is made as small as possible, the thrust releasing force becomes larger, and further, if the stepped portion 10 is subjected to a drawing process of bending it by approximately 90 degrees in the radial direction, the same. The thrust release force is large and the ring 3 is more completely prevented from coming off.

Needless to say, the present invention is not limited to the above embodiment, and the ring 3 may be a simple ring such as a collar.

Thus, the inner diameter surface is not turned from the end portion of the pipe having the predetermined diameter in the radial direction and the axial direction by a predetermined length, and the inner diameter surface which is almost equal to the axial length and the outer diameter of the bearing is formed. In addition, there is no need to press-fit the bearing from the end portion, and further, it is not necessary to apply the bearing retaining process to the end portion.

[0021]

According to the present invention described above, since the turning of the inner diameter of the pipe is not required, the turning process can be omitted, and since the pipe is drawn, the wall thickness of the ring holding portion can be made constant, and It is possible to form a constant ring holding part even if there are variations in the ring outer diameter and the pipe inner diameter,
In the manufacturing of the steering column jacket, it is possible to significantly shorten the process and reduce the cost.

[Brief description of drawings]

FIG. 1 is a semi-sectional side view of a tube end portion of a jacket tube showing an example in which the present invention is applied to a steering column.

FIG. 2 is a half sectional side view of an internal fitting manufacturing process.

FIG. 3 is a half cross-sectional side view of an internal fitting manufacturing process.

FIG. 4 is a half sectional side view of a jacket tube in a conventional steering column.

[Explanation of symbols]

 1 ... Mandrel 2 ... Pipe 3 ... Ring 4 ... Receiving stand 5 ... Drawing die 6 ... Head 7 ... Drawing part 8 ... Ring pressing part 9, 10 ... Step part

Claims (3)

[Claims] 1. A bearing to be fitted in an end portion of a jacket tube is prevented from coming off by a step portion formed by drawing one end portion of the jacket tube and wrapping radially toward both axial end portions of the bearing. The steering tube jacket tube is characterized by being tightened. 2. A ring is fitted to the end of the mandrel, the mandrel is inserted into a pipe having a diameter larger than that of the ring, and the pipe end is drawn toward the ring by a predetermined length. The jacket tube of the steering column is characterized in that a step portion of the pipe is formed on both ends in the axial direction of the ring so as to wrap around in the radial direction so as to prevent the ring from coming off and tighten it. Manufacturing method. 3. The method for manufacturing a jacket tube for a steering column according to claim 2, wherein the pipe is a jacket tube for a steering column, and the ring is a bearing for supporting a steering shaft.