JPH026028A - Method for working spherical surface of spherical head section - Google Patents

Abstract

PURPOSE:To apply a form rolling load to the entire surface of a spherical head section and to uniformly enhance the roughness of the entire spherical surface of the section by forming the spherical head section so that its equatorial diameter can become a little longer than its meridian diameter. CONSTITUTION:The spherical surface 4 of the spherical head section 3 of a ball stud 1 formed to an orange-like shape is finished as it is by form rolling without machining. Since the equatorial radius 6 of the section 3 is made slightly longer than the meridian radius 8 of the section 3, the spherical surface 5 at the equatorial section is abutted with the form rolling surface 21 of a form rolling roller 20 prior abutting to the spherical surface 7 at the end sections. Therefore, form rolling is started initially to the spherical surface 5 which is positioned to nearly center of the section 3 in the axial direction and a step- difference 13 is corrected. Thereafter, the spherical head section 3 is reformed to a real sphere by gradually increasing the area of the spherical surface abutting with the form rolling surface 21 of the roller 20 by means of the pressing force of the roller 20 while releasing the blank volume of the section 3 to both ends in the axial direction in a well-balanced state.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a ball head of a part having a ball head, such as a pole stud for a ball jaw used in, for example, a steering system and a suspension system of an automobile. This paper relates to a spherical surface machining method.

Conventional technology The conventional spherical surface processing method by rolling a ball head involves forging or additionally cutting the ball head so that it becomes a true sphere, which is the shape after rolling. Therefore, there is a method in which the ball is formed from the beginning and then finished by rolling with a rolling roller in order to increase the surface roughness of the spherical surface of the ball head.

Problems to be Solved by the Invention When using the above-mentioned method to roll and finish the spherical surface of the ball head of a pole stud, for example, in the method of forming the ball head by cutting, it is difficult to form the ball head by cutting. At this stage, the ball head has already been formed into a perfect sphere. Therefore, since the spherical surface of the spherical head and the rolling surface of the rolling roller completely match before rolling starts, there is a problem that even if the load is increased to increase the surface roughness, the surface roughness does not increase. In other words, the equatorial spherical surface of the ball head during rotation of the pole stud axis has virtually no place for the material volume to escape even if it receives the pressing force from the rolling roller, and it becomes undeformable like a rigid body. . Therefore, no rolling load is applied to the spherical surface near the end, resulting in no increase in surface roughness. In addition, forging rough forming,
It also has the disadvantage of being expensive because it requires two steps: cutting.

Therefore, if the ball head is formed into a true sphere by forging only, as shown in the left half of FIG. ,
The handle-side hemisphere 315 and the opposite-handle hemisphere 314 of the ball head 303 may be misaligned, and a step 313 may be formed on the equatorial spherical surface 305. Or, as shown in Fig. 3, a spherical surface 405 with an equatorial part corresponding to the gap between the split parts of the spherical head mold.
A convex ring 413 may be formed on the surface.

Of these, the spherical surface 30 of the spherical head 303 with the step 313
4, as shown in the left half of FIG.
22 hemispherical parts are formed. Therefore, the ball head 3
The balance of the rolling load applied to 03 becomes uneven, and therefore the surface roughness does not increase uniformly.

In addition, the spherical surface 4 of the spherical head 403 where the convex ring 413 is formed
When 04 is finished rolling, as shown on the right side of Fig. 4, the convex ring 413 comes into contact with the rolling surface 421 of the rolling roller 420 and is corrected, but the spherical head 403 itself is not a true sphere. After that, a situation similar to the above-mentioned case of forming the spherical head by cutting occurs, and as a result, the spherical surface 407 near the end
There is a problem that the surface roughness does not increase.

Means for Solving the Problems A spherical head is formed in advance into a spherical shape so that the diameter of the equatorial part of the spherical head perpendicular to the axial direction thereof is a very small length,
Thereafter, a rolling process is performed to correct the slight major axis of the spherical surface of the spherical head.

Function: In the rolling finishing process, rolling starts from the equatorial spherical surface located approximately in the center of the ball head in the axial direction, and then the material volume is released in a well-balanced manner to both ends in one direction along the axis, while the spherical surface and the rolling roller are The contact area with the rolled surface can be gradually increased.

Example Embodiments of the present invention will be described below based on the drawings.

FIG. 1 shows the rolling process according to the first embodiment of the present invention, with the left half showing the state at the start of rolling, and the right half showing the state at the end of rolling.

1 is a ball stud with a ball head 3 used for ball joints, etc., and 2 is a handle connected to the ball head 3.

20. 20 is a pair of rolling rollers with a concave spherical rolling surface 2.
1.21.

Next, a method of machining the spherical surface of the ball head 3 of the ball stud 1 will be explained.

First, the ball head 3 is forged. This ball head 3 after forging
As shown in the left half of Figure 1, the shape of is, if the radius after rolling is L, the equatorial radius 6 perpendicular to the axial direction is length L+a (a>0), and the radius near the end is 8. is length L + b
(a > 0 > b).

In other words, the spherical head 3 is forged into a flat, so-called tangerine shape, in which the equatorial radius 6 is longer than the radius 8 near the end. In this ball head 3, the handle side hemisphere 15 and the credit side hemisphere 14 are slightly shifted. Therefore, a step 13 is formed on the spherical surface near the equator. This is caused by the hemispherical portions of the ball head mold for forming the ball head 3 being shifted from each other during forging.

Next, the spherical surface 4 of the tangerine-shaped ball head 3 of the ball stud 1 is rolled and finished without being cut.

That is, as shown in the left half of FIG.
20, rotate the ball stud 1 ball head 3,
It is pressed against the rolling surfaces 21, 21 of the rotating rolling rollers 20, 20.

As mentioned above, since the spherical head 3 is formed so that the radius 6 of the equatorial portion is larger than the radius 8 near the end, the rolling roller 2
The equatorial spherical surface 5 contacts the rolled surfaces 21.21 of 0 and 20 earlier than the end portion spherical surface 7. Therefore, rolling is started from the equatorial spherical surface 5 located approximately at the center in the axial direction of the ball head 3, the step 13 is corrected, and then the material of the ball head 3 is The entire ball head 3 is corrected into a true sphere by gradually increasing the contact area between the spherical surface 4 and the rolling surfaces 21, 21 of the rolling rollers 20, 20 while releasing the volume to both ends in the axial direction in a well-balanced manner. I will go there. Therefore, a rolling load is applied to the entire ball head 3, and after rolling is completed, the tangerine shape is corrected as shown on the right side of FIG. 1, and the spherical surface 4 of the ball head 3 and the rolling roller 20 , 20 coincide with the rolled surfaces 21 and 21.

In other words, the ball head 3 after rolling becomes a true sphere with a flat diameter 10 at the equator and a radius 12 near the end, both of which are L, and at the same time, both the spherical surface 9 at the equator and the spherical surface 11 near the end have surface roughness. is increasing evenly.

In the first embodiment, when the ball head is forged, the ball head of the ball stud has a step near the equator due to mutual misalignment of the hemispherical parts that make up the ball head mold. As shown in the left half of FIG. 2 as a second embodiment, a ball stud 101 has a convex ring 113 formed in a portion corresponding to the gap between the split parts of a ball head mold. The surface roughness of the spherical surface 104 can be increased by processing the spherical head 103 in the same manner.

This second embodiment will be explained below.

FIG. 2 shows the same state as FIG. 1 during the rolling process of the ball head 103 of the ball stud 101.

120 and 120 are a pair of rolling rollers having concave spherical rolling surfaces 121, 121. In addition, this rolling roller 12
0,120. has convex curved neck inserts 122, 122 adjacent to the handle 102 side of the ball stud 101 with a rolled surface 121°121. This neck pocket 122, 122
is for forming an annular concave neck portion 115 between the handle 102 and the ball head 103 of the ball stud 101 to be rolled. Therefore, as shown in the left half of FIG. 2, when the ball stud 101 is forged, the neck portion is not provided, and the straight portion 114 is extended in the axial direction.
It is connected to the ball head 103.

Moreover, the shape of the ball head 103 after forging is, assuming that the radius after rolling is 10OL, the flat diameter of the equatorial part perpendicular to the axial direction is 10
6 has a length of 100L+100a (100a>O), and the radius near the end 108 has a length of 100L+100b (100
a>0>100b). That is, it is orange-shaped like the first embodiment. As described above, a convex ring 113 is formed on the spherical surface of the spherical head 103 near the equator.

Therefore, when rolling starts, the rolling surface 1 of the rolling roller 120
21, 121, the convex ring 113 first contacts and starts rolling. Immediately after the start of rolling, this convex ring 113 is straightened, and then the rolling surface 1 of the rolling roller 120.
21, 121 and the equatorial spherical surface 105 come into contact and the rolling progresses, and as in the first embodiment, after the rolling is completed, the second
As shown on the right side of the figure, the tangerine shape is corrected and the ball head 1
03 Spherical surface 104 and rolling surface 1 of rolling rollers 120, 120
21,121 match.

In other words, the spherical head 103 is a true sphere with a flat diameter 110 at the equator and a radius 112 near the end of 10OL, and at the same time, the surface roughness of the spherical surface 109 at the equator and the spherical surface 111 near the end are uniformly increased. ing.

In addition, in this embodiment, the rolling roller 120.120
Since the neck insertion portions 122, 122 are provided, the neck portion 115 can also be formed at the same time in this rolling process.

In the first and second embodiments, the spherical head is formed by forging, but the surface roughness of the spherical head can be similarly improved if the spherical head is formed by cutting.

Effects As described above, according to the present invention, in the rolling finishing process, rolling is started from the equatorial spherical surface located approximately at the center in the axial direction of the ball head, and then the material volume is balanced toward both ends in the axial direction. Good (The contact area between the spherical surface and the rolling surface of the rolling roller is gradually increased while rolling, and the rolling load can be applied to the entire surface of the ball head, so the surface roughness of the spherical surface of the ball head can be improved. can be uniformly increased over the entire surface.

[Brief explanation of the drawing]

1 and 2 show the rolling process according to an embodiment of the present invention, FIG. 1 is the first embodiment, and FIG. 2 is the second embodiment.
FIG. 3 is a partially sectional plan view showing the second embodiment. FIG. 3 is a plan view of a separate ball stud in which the left half and right half are formed by a conventional method. The left half and right half of FIG. 4 are partially sectional plan views showing the rolling process of each ball stud shown in FIG. 3. (Explanation of symbols) - Ball head.・Spherical surface. patent applicant

Claims (1)

[Claims] The spherical head 3 is formed in advance into a spherical shape so that the diameter of the equatorial portion of the spherical head 3, which is perpendicular to the axial direction thereof, is a slight major axis, and then the minor major axis of the spherical surface 4 of the spherical head 3 is shaped. A method for processing a spherical surface of a spherical head, which is characterized by applying a rolling process for correction.