Stud having a spherical surface bearing

To make it easy to manufacture a stud 1 provided with a spherical surface bearing, a race (3) is composed of a first member (3a) and a second member (3b) so that a ball receiving portion (301) is separated. Coupling surfaces (5) and (6) that couple with each other are formed in the first and second members (3a) and (3b). Screw portions are formed on the coupling surfaces (5) and (6), respectively. When the stud (1) provided with the spherical surface bearing is manufactured, a ball (2a) is held by the first and second members formed indivisually, and the first and second members (3a) and (3b) are threadably engaged with each other at the screw portions. In this case, by adjusting an amount of a engagement at the screw portion, the positional relationship between the first and second members (3a) and (3b) is set as desired, to thereby suitably adjust a gap between the ball receiving portion (301) of the race (3) and the ball (2a). The positional relationship between the first and second members (3a) and (3b) is fixed by a pin (4) to thereby eliminate the gap change.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a stud having a spherical surface bearing 
for allowing two members, fixed to each other, to angularly move relative 
to each other. 
2. Description of the Related Art 
When two members are to be fixed to each other, in some cases, it is 
preferable to allow one member to move relative to the other by a constant 
amount of movement. For instance, when a window glass is fixed to a 
building or the like, in order to enhance a wind pressure resistance, a 
seismic resistance or the like, the window glass is fixed so as to allow a 
constant amount of the window glass movement. In this case, a stud 
provided at one end with a spherical surface bearing is used for fixing 
the respective members so as to be movable to each other by the spherical 
surface bearing. FIG. 2 shows the stud 1 provided with the spherical 
surface bearing. The stud 1 provided with the spherical surface bearing is 
composed of a stud rod 2 provided with one end with a ball 2a and a race 
3, wherein the ball 2a is supported by the race 3 at the spherical surface 
bearing. In this case, the race 3 holds the ball 2a by a ball receiving 
portion 301 so that the ball 2a may be prevented from falling off from the 
race 3 and may be swung. Also, the ball receiving portion 301 is opened to 
the outside through a conical wall surface 302 having a predetermined 
angle .theta. relative to an axis C of the race 3. The stud rod 2 projects 
to the outside of the race 3 from the conical wall surface 302. 
Accordingly, the stud rod 2 is held swivellable within the range of the 
angle .theta. relative to the axis C of the race 3 about a center of the 
ball 2a. 
By the way, upon manufacturing the stud having the above described 
structure, the conventional technology suffers from the following 
problems. As described above, the ball receiving portion 301 of the race 3 
has a necessity to prevent by itself the ball 2a from falling off by 
itself and to hold the ball 2a for allowing the swing movement of the ball 
2a. Accordingly, a continuous portion 303 between the ball receiving 
portion 301 and the conical wall surface 302 constitute an "under-cut". 
Conventionally, the race 3 has been formed into an integral part by plastic 
deformation. In this process, in the first place, the ball 2a is inserted 
into a material for the race 3 which substantially forms a cylinder. Then, 
a pressure is applied to the material from the outside to firmly fasten 
the ball 2a. As a result, the shape of the ball 2a is transferred to the 
material. In this case, when the shape of the ball 2a is transferred to 
the material, it is necessary to form the ball receiving portion 301 and 
the continuous portion 303. For this reason, upon the completion of the 
plastic deformation, there is a tendency that the force of the race 3 for 
holding the ball 2a is excessive, so that the swing motion of the ball 2a 
has been impossible. Accordingly, it is necessary to slightly increase a 
diameter of the ball receiving portion 301 as a post-step so as to form a 
gap such that the ball 2a may be swivelled relative to the ball receiving 
portion 301. However, regarding the post-step, almost all the steps have 
depended upon the experience and sense of the workers. Therefore, it has 
been very difficult to apply it to the work easily. Also, in order to 
facilitate the deformation of the material for the race 3, a setting of 
the thickness of the race is limited, and in addition, a pressure applied 
to the ball 2a (a pressure such that the ball 2a is deformed) should not 
be excessive. To meet these requirements, a pressure applied to the race 3 
has been restricted, as a result, it is difficult to determine the shape 
of the race as desired. 
Accordingly, there has been an approach to first form divided members of 
the race 3 (for example, ones divided along the line A--A of FIG. 2) and 
to weld the two members together after holding the balls by the divided 
members. However, also in this method, it has been difficult to optimally 
set the gap between the ball 2a and the ball receiving portion 301 after 
welding. It is thus difficult to finely adjust the gap after welding. 
SUMMARY OF THE INVENTION 
In view of the foregoing problems, an object of the present invention is to 
provide a stud which can be manufactured at low cost and used in a wide 
field of application to thereby enhance a commercial value of the stud 
having a spherical surface bearing by facilitating the adjustment of a gap 
between a ball of a stud and a ball receiving portion of a race without 
any limit to a thickness, a shape or the like. 
A means to solve the above defect in the present invention, in a stud 
having a spherical surface bearing, provided at one end with a ball held 
by a race, is characterized in that a ball receiving portion of the race 
is composed of two members so that may be separated, in which each of said 
two members having a coupling surface which is coupled with the other, and 
screw portions are formed on each coupling surface. 
In this arrangement, the race is composed of two members. When each member 
is disassembled, the ball receiving portion may be separated. Also, each 
member has the coupling surface that couples with the other. The screw 
portions are formed on the respective coupling surfaces. When the stud is 
manufactured, the ball of the stud is held by the respective ball 
receiving portions formed independently with each other. The two members 
are fixed to each other by the screw portions penetrating the coupling 
surfaces of the respective members. In this case, by adjusting an amount 
of the engagement at the screw portions, the positional relationship 
between the two members may be set as desired. Accordingly, it is possible 
to set a gap between the ball receiving portion of the race and the ball 
as desired. By the way, the adjustment of the gap between the ball 
receiving portion of the race and the ball is performed not by deforming 
the race but by adjusting the amount of the engagement at the screw 
portions. 
Also, preferably, the stud may further comprise a fixing means for fixing a 
positional relationship between the coupling surfaces. By the fixing 
means, it is possible to position the two members constituting the race. 
Additionally, the respective members formed by dividing a single member 
may be firmly fixed to each other as a single race.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The present invention will now be described with reference to FIG. 1. 
Incidentally, in FIG. 1, the same reference numerals are used to indicate 
the same members or parts that have been explained in conjunction with the 
conventional technique. 
FIG. 1 shows a stud 1 provided with a spherical surface bearing in 
accordance with an embodiment of the present invention. The stud 1 is 
composed of a stud rod 2 provided at one end with a ball 2a and a race 3 
for holding the ball 2a. Furthermore, the race 3 is composed of a first 
member 3a and a second member 3b for separating from each other. Ball 
receiving portions 301 may be separated. The second member 3b has the ball 
receiving portion 301 and a conical wall surface 302 having a 
predetermined angle .theta. Then, the continuous portion 303 between ball 
receiving portion 301 and the conical wall surface 302 constitute the 
under-cut. 
By the way, coupling surfaces 5 and 6 of a first members 3a and a second 
member 3b are parallel to each other. Screw portions are formed in the 
coupling surfaces 5 and 6, respectively. The first member 3a and the 
second member 3b are made integrally with each other by the connection of 
the screw portions. Also, a pin 4 is used to pass through the coupling 
surfaces 5 and 6 of the first and the second members 3a and 3b. 
Now, a manufacturing process of the stud 1 provided with the spherical 
surface bearing according to the embodiment of the invention will be 
explained. The stud rod 2 provided at one end with the ball 2a is the same 
as the conventional one. With respect to the race 3, the first member 3a 
and the second member 3b are formed independently with each other. In this 
process, the first member 3a and the second member 3b are formed in such a 
way that a further forming precess is not necessary to be applied as the 
following steps, because, by merely integrating the both members, the 
configuration of the race 3 is formed. 
Subsequently, in the assembly steps for respective members, first of all, 
the ball 2a of the stud rod 2 is brought into contact with the ball 
receiving portion 301 of the first member 3a. Next, the second member 3b 
is inserted into the stud rod 2. The ball receiving portion 301 of the 
second member 3b is moved to a position to substantially come in contact 
with the ball 2a. Then, the screw portion formed on the coupling surface 5 
of the first member 3a and the screw portion formed on the coupling 
surface 6 of the second member 3b are threadably engaged with each other 
so that the ball 2a is clamped by the respective ball receiving portions 
301 of both members. In this case, by adjusting the amount of the 
engagement at the screw portions, the positional relationship between the 
first and second members 3a and 3b is set as desired. According to this, a 
suitable gap is formed so that the ball 2a and the ball receiving portion 
301 may be swivelled relative to each other without any displacement. 
Also, when the desired amount of the engagement at the screw portions has 
been set, a pin 4 as a fixing means (also called locking means) is 
press-fitted so as to penetrate the coupling surfaces 5 and 6 of the first 
and second members 3a and 3b to complete the stud forming process. By 
inserting the pin like the above, the positional relationship between the 
coupling surfaces 5 and 6 is fixed and it is possible to prevent an 
occurrence of any change of the gap between the ball receiving portion 301 
and the ball 2a and to prevent the disassembling of the first member 3a 
and the second member 3b. 
In the stud 1 provided with the spherical surface bearing manufactured in 
the above-described way according to the present embodiment, the ball 
receiving portion 301 of the race 3 is opened to the outside through a 
conical wall surface 302 having a predetermined angle .theta., and the 
stud rod 2 is projected to the outside of the race 3 from the conical wall 
surface 302. Accordingly, the stud rod 2 is made swivellable within the 
range of the angle .theta. relative to the axis C of the race 3 about a 
center of the ball 2a. 
The function and effect obtained from the present embodiment of the above 
structure is as follows. The race 3 is composed of the first and second 
members 3a and 3b so that the ball receiving portion 301 can be separated. 
Then, the screw portions are formed on the coupling surfaces 5 and 6 of 
the first and second members 3a and 3b, so that the positional 
relationship between the first and second members 3a and 3b can be set as 
desired by adjusting an amount of the engagement at the screw portions. 
Therefore, in the ball receiving portion 301 of the race 3, the gap 
between the ball 2a and the ball receiving portion 301 can be adjusted 
readily so that the ball 2a may be prevented from falling off from the 
race 3 and also the ball 2a can be held angularly movable. 
Further, a pin 4 as a fixing means is press-fitted so as to penetrate the 
coupling surfaces 5 and 6 of the first and second members 3a and 3b to 
thereby fix the positional relationship between the coupling surfaces 5 
and 6. According to the above, it is therefore possible to prevent an 
occurrence of any change at the gap between the ball receiving portion 301 
and the ball 2a and to prevent the disassembling of the first member 3a 
and the second member 3b. Also, it is possible to fix the both surfaces by 
using a screw or an adhesive 7 or the like instead of the pin 4 as the 
fixing means. One skilled in the art would know how to apply an adhesive 7 
to coupling surfaces 5 and 6. 
Further, when the first member 3a and the second member 3b are formed 
independently with each other, the first member 3a and the second member 
3b are formed in such a way that a further forming process is not 
necessary to be applied as the following step, because, by merely 
integrating the both members, the configuration of the race 3 is formed. 
Since the respective members are formed independently with each other, it 
is easy to set the shape and the thickness of the race 3. It is therefore 
possible to enhance degrees of freedom in shape and thickness. 
With such an arrangement of the present invention, it is possible to play 
the following effect. In the stud provided with the spherical surface 
bearing, the race is composed of two members, in which each member has the 
coupling surface which couples with the other, and each coupling surface 
has a screw portion, respectively, therefore, upon manufacturing the stud, 
the ball of the stud may be clamped by the ball receiving portion, of 
which each member is formed independently, and the two members may be 
fixed to each other by the screw portions formed on the coupling surfaces 
of the rspective members. In this case, by adjusting the amount of the 
engagement at the screw portions, it makes possible to be set the position 
between each member at will. Also, it is possible to set the gap between 
the ball receiving portion of the race and the ball as desired. Namely, 
the adjustment of the gap between the ball receiving portion of the race 
and the ball, which has been difficult to attain, may readily be effected 
only by adjusting the amount of the engagement at the screw portions of 
the constituent parts of the race. Accordingly, it is unnecessary to 
depend largely on a skill or experience of the worker, and it is possible 
to remarkably reduce the manufacturing cost. 
Also, the adjustment of the gap between the ball receiving portion of the 
race and the ball is carried out only by the adjustment of the amount of 
the engagement at the screw portions. This does not depend upon such 
method as to bring the race into pressing contact with the surface of the 
ball to transfer its spherical shape as in conventional case. This makes 
it possible to set the shape and the thickness of the race as desired. It 
is therefore possible to expand a field of application of the stud 
provided with the spherical surface bearing. 
Furthermore, in the stud having the spherical surface bearing, the fixing 
means for fixing the positional relationship between the coupling surfaces 
is used to thereby position the two members constituting the race, i.e., 
without an occurrence of any change at the gap between the ball and the 
ball receiving portion. Also, the respective members formed by dividing a 
single member are firmly fixed as a single race to make it possible to 
prevent disconnecting with each other. It is therefore possible to enhance 
the reliability of the products. 
Various details of the invention may be changed without departing from its 
spirit nor its scope. Furthermore, the foregoing description of the 
embodiments according to the present invention is provided for the purpose 
of illustration only, and not for the purpose of limiting the invention as 
defined by the appended claims and their equivalents.