JPH0750083Y2 - Guided center - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a center that supports a plurality of types of shafts when machining with a small machine tool.

[0002]

2. Description of the Related Art Conventionally, when a shaft having a small outer diameter of about several millimeters is supported by a center having a conical shape, it takes time and effort to insert the center into the center hole because the center hole of the shaft is small. Therefore, as shown in FIG. 3, a guide portion 2 having a conical recessed inclined surface 21 is provided on the outer periphery of the center 1 ', and the outer diameter of the shaft 3 is guided in advance so that the guide portion 2 is substantially centered. When the shaft 3 is guided, the tip of the center 1'is inserted into the center hole 31 'of the shaft 3.

[0003]

However, a shaft having a thread at its tip or a shaft 3 having a relatively large diameter is used.
When a small-diameter shaft is supported by the center 1'for supporting the shaft 1, the outer diameter of the center 1 ', that is, the inner diameter of the guide portion 2 becomes large.
Since it does not come into contact with the inclined surface 21 of the above, the center having the above-described configuration has a drawback that the guide portion of the small-diameter shaft cannot play a role and the labor for supporting the center cannot be saved. It is an object of the present invention to provide a center that can reliably guide a shaft having a different outer diameter or a shaft having a screw.

[0004]

SUMMARY OF THE INVENTION According to the present invention, a conical portion for supporting a center hole of a shaft is provided at a tip end, and a conical surface is inclined inwardly of an opening opening in the outer periphery of a side surface in the direction of the conical portion. In a center with a guide in which a guide portion provided with a surface is fitted and a compression spring that acts in a direction to push the guide portion toward the tip of the center is provided, the longitudinal side surface of the center is parallel to the axial direction. It is formed by two arc portions and two plane portions parallel to each other, and the distance between the two plane portions is smaller than the minimum diameter of the shaft to be used,
The guide portion is provided with a sliding hole that fits into the circular arc portion and the flat surface portion.

[0005]

[Function] Since the center is formed by cutting both side surfaces of the cylinder in a plane and the sliding hole to be fitted into the center is provided in the guide portion, both the small diameter shaft and the large diameter shaft are guided by the guide portion, A center hole is inserted in the cone of the center and can be supported by one center. .

[0006]

Embodiments of the present invention will be described with reference to the drawings.
1 (a) is a side sectional view of an essential part showing an embodiment of the present invention, FIG.
(B) is the front view, and the center 1 has a flange 11 at the base.
The center 1 is formed by two arc portions 12 parallel to the axial direction and two plane portions 13 parallel to each other in the longitudinal direction of the center 1, and both side surfaces of the cylindrical shape are cut along a plane. The distance L between the two flat portions 13 is smaller than the minimum diameter d of the shaft 3'to be used. A conical portion 14 is provided at the tip of the center 1. On the outer circumference of the center 1,
A guide portion 2 having a sliding hole 21 that fits into the arc portion 12 and the flat surface portion 13 is provided, and the tip of the opening portion of the guide portion 2 that opens toward the tip end of the center 1 has a conical surface shape recessed inward. The inclined surface 22 is provided. A compression spring 4 is provided between the flange 11 and the guide portion 2 so as to push the guide 2 toward the tip of the center 1. A casing 5 is provided on the outer periphery of the guide portion 2, and a stopper 23 protruding inside the casing 5 is abutted by a flange 23 protruding outside the guide portion 2 to prevent the guide portion 2 from coming off the center 1. .

Now, when supporting a small-diameter shaft 3'on the center 1, as shown in FIG. 1, the end of the shaft 3'is pressed against the inclined surface 22 of the guide portion 2 to resist the compression spring 4. When pressed, the distance L between the two flat portions is smaller than the diameter d of the shaft 3 ′, so that the portion of the inclined surface 22 in contact with the flat portion 13 is guided to the center of the center 1 and the center hole 3
The conical portion 14 of the center 1 is inserted into 1 ', and the ring-shaped portion shown by the dotted line in FIG.

When supporting the large-diameter shaft 3 on the center 1, as shown in FIG.
When the end portion of the shaft 3 is pressed against 2 and pressed against the compression spring 4, it is contacted and guided over the entire circumference of the inclined surface 22, and the conical portion 14 of the center 1 enters the center hole 31.
The ring-shaped part shown by the dotted line in FIG. 2B is in contact with and supported.

As described above, by providing a center having a cylindrical surface on both sides cut with a flat surface and a sliding hole fitted in the center in the guide portion, both the small diameter shaft and the large diameter shaft can be formed by one center. Can be supported.

[0010]

As described above, according to the present invention, a wide range of shafts from a relatively small diameter shaft to a large diameter shaft can be supported by a single center, so that a setup change is required. The shaft can be installed without doing this, which has the effect of greatly reducing the work time.

[Brief description of drawings]

FIG. 1 (a) is a side sectional view showing an embodiment of the present invention.

FIG. 1 (b) is a front view showing an embodiment of the present invention.

FIG. 2 (a) is a side sectional view for explaining the operation of the different shaft of the present invention.

FIG. 2 (b) is a front view for explaining the operation of the different shaft of the present invention.

FIG. 3 is a side sectional view showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Center 12 Arc part 13 Plane part 14 Conical part 2 Guide part 21 Sliding hole 22 Inclined surface 3, 3'Shaft 31, 31 'Center hole 4 Compression spring 5 Casing

Claims (1)

[Scope of utility model registration request] 1. A guide portion having a conical portion for supporting a center hole of a shaft at a tip thereof, and a conical inclined surface recessed inside an opening opening in the direction of the conical portion is fitted to an outer periphery of a side surface. In the center with a guide provided with a compression spring that acts to push the guide part toward the tip of the center, the side surfaces in the longitudinal direction of the center are parallel to two arcuate parts parallel to the axial direction. It is formed by two flat parts, and the distance between the two flat parts is smaller than the minimum diameter of the shaft to be used, and the guide part is provided with a sliding hole that fits into the arc part and the flat part. A center with a guide.