JPS6240727Y2 - - Google Patents

Description

[Detailed Description of the Invention] Technical Field of the Invention The present invention relates to a centering device for centering and positioning a cylindrical workpiece or a workpiece having a partially cylindrical portion.

Technical background of the invention In general, a collect chuck is often used as a method for centering and gripping a workpiece based on the inner surface of the workpiece in a machine tool. FIG. 1 shows a longitudinal sectional view of a conventional collector chuck.

an actuator 2 and a main shaft 3 attached to the support frame 1; a drawbar 4 that passes through the main shaft 3 and the support frame 1 and is moved in the axial direction by the actuator 2 and has a tapered portion 4a at the tip; The taper portion of the collet 5 comes into contact with the taper portion 4a. The taper portion 4a of the drawbar 4 is moved by the actuator 2 in the direction of the arrow 6 to enlarge the collet 5. At the same time, the collet 5 is moved in the direction of the arrow 6 by the taper part 4a of the drawbar 4, and the outer diameter of the collet 5 is evenly expanded by the taper part 3a provided on the main shaft 3.
The workpiece 7 is pressed against the inner surface of the workpiece 7 placed on the outside of the workpiece 7 to center the workpiece 7, and the end surface of the workpiece 7 comes into contact with a positioning piece 8 provided on the main shaft to position the workpiece 7 in the axial direction. conduct.

Problems with the Background Art The conventional collect chuck described above has a mechanism that expands the collet 5 by moving the drawbar 4 and pulls the workpiece 7 toward the positioning piece 8 provided on the main shaft. Since the amount of expansion cannot be large due to the structure, depending on the dimensional accuracy of the inner surface of the workpiece 7 that serves as the centering and gripping surface, the end surface of the workpiece 7 may not come into contact with the positioning piece 8, or the collet 5 may A problem arises in that the workpiece 7 is not gripped, which increases the cost due to the need to improve the accuracy of the inner dimensions of the gripping surface, and the need to prepare a large number of collects with small dimensional differences in outer diameter. The inner gripping portion of the workpiece cannot sufficiently grip unprocessed products such as castings, resulting in a large number of defective products.

Purpose of the invention The present invention was made in order to eliminate this drawback, and even if the inner gripping part of the workpiece is an unprocessed product such as a casting, the gripping part can be To provide a centering device capable of positioning a workpiece in the axial direction after reliably holding the inner surface of the workpiece, even if the machining dimensions of the inner surface of the workpiece vary, without preparing various collets. It is in.

Summary of the invention Consists of a drawbar with a tapered part and a slider that comes into contact with the taper part of the drawbar, moves in the radial direction in a long hole through which the main shaft passes, and has a replaceable pin. By moving and pressing against the inner surface of the workpiece, the workpiece is positioned in the radial direction, and the main shaft, which is gripped by the workpiece, is moved in the axial direction.
This centering device is characterized in that it positions a workpiece in the axial direction by coming into contact with a stopper.

Embodiment of the Invention The centering device of the invention will be explained below with reference to drawings of one embodiment. Figure 2 is a cross-sectional plan view of the present invention;
FIG. 3 is a cross-sectional view taken along the - line in FIG.
and an actuator 11 attached to this support frame 10, and a flange 2 that penetrates in the radial direction with a flange that is slidable in the axial direction in a guide hole 10a bored in the support frame and held by a spring 12. A main shaft 13 having two long holes 13a in the axial direction, and a support frame 1.
0 and the main shaft 13, and the actuator 1
1, the two tapered parts 1
4a, and a drawbar 14 that abuts each tapered portion 14a of the drawbar 14, moves in the radial direction within the elongated hole 13a of the main shaft 13, and has a replaceable pin 15 on the outside.
The main shaft 13 constantly presses the slider 16 toward the center, a spring 17 wound around the outer circumference of the slider 16, and a positioning piece 18 provided on the support frame 10.

Now, when the workpiece 19 placed on the table 9 is inserted into the centering device until the end surface contacts the positioning piece 18 and the actuator 11 is operated, the drawbar 14 moves in the direction of the arrow 20. The main shaft 13 is
The slider 16 is pushed out evenly in the radial direction along the long hole 13a against the spring 17, and the slider 16
A pin 15 provided on the outside of the workpiece 6 is pressed against the inner surface of the workpiece 19. At this time, the slider 16 moves evenly, so even if the workpiece 19 is misaligned during insertion or the inner surface of the workpiece 19 is not a perfect circle, such as an unprocessed cast product, it will come into contact first. pin 1
5, the workpiece 19 is moved in the left and right direction to the average position of the inner surface shape of the workpiece 19,
The pins 15 on both sides come into contact with the inner surface of the workpiece 19, and the radial centering and gripping operation of the workpiece 19 is completed.

However, although the end surface of the workpiece 19 was originally brought into contact with the positioning piece 18 manually, the position of the workpiece 19 is often shifted and separated from the positioning piece 18 due to this centering operation. Therefore, the position of the workpiece 19 in the axial direction shifts, causing problems in subsequent machining. In order to solve this problem, the next positioning operation is performed successively after the centering and gripping operations are completed. The slider 16, which has the pin 15 pressed against the inner surface of the workpiece 16, is no longer able to move outward and is in a state where it grips the workpiece 19 by the initial tensile force of the actuator 11 in the direction of the arrow 20. The workpiece 19 moves in the direction of the arrow 20 together with the main shaft 13 and the drawbar 14 sliding through the guide hole 10a of the support frame 10 against the spring 12, and the end surface of the workpiece 19 comes into contact with the positioning piece 18 and stops, and the workpiece 19 moves in the axial direction. Positioning is complete. When the centering and positioning in the radial and axial directions are completed, the workpiece 19 is fixed to the table 9 by the clamp 21.

In addition, the pin 15 provided on the outside of the slider 16 makes point contact with the inner surface of the workpiece 19 when the inner surface of the workpiece 19 is an unprocessed cast product, etc. This is effective for absorbing errors, and even if the dimensional accuracy changes, it can be easily and inexpensively replaced by replacing only the pin 15.

Although the embodiment of the present invention has been described using two sliders, the same effect can be expected even if the number of sliders is two or more, such as three or four.

Effects of the Invention As explained above, in the present invention, the slider expands in the radial direction, ensures centering and gripping of the workpiece in the radial direction using pins provided on the outside of the slider, and then moves in the axial direction. Since the positioning in the axial direction can be performed reliably by using the slider, it is possible to completely eliminate any problems that may occur during machining after this, and since the amount of expansion of the slider in the radial direction is large, it is easy to do so by simply replacing the pins. It can be used for workpieces with different inner diameters, and even if the inner surface of the workpiece is an unprocessed product such as a casting, the workpiece can be processed reliably without being affected by shape errors such as burrs on the inner surface of the casting. It is possible to provide a highly reliable centering device that is extremely economical and capable of centering and positioning.

[Brief explanation of the drawing]

Figure 1 is a longitudinal cross-sectional view of a conventional collect chuck.
Figure 2 is a cross-sectional view showing one embodiment of the present invention;
The figure is a sectional view taken along the line -- in FIG. 2. 1, 10... Support frame, 2, 11... Actuator, 3, 13... Main shaft, 4, 14... Draw bar, 6, 20... Arrow direction, 7, 19... Workpiece, 8, 18... ...Positioning piece, 10a...Guide hole, 15...Pin, 16...Slider.

Claims (1)

[Scope of utility model registration request] a support frame, an actuator attached to the support frame, a main shaft attached to the support frame and having two or more axially long holes passing through the main shaft and the support frame; A drawbar that is moved in the axial direction by an actuator and has two or more tapered portions spaced apart in the axial direction on its outer circumferential surface, and a drawbar that abuts each of the tapered portions of the drawbar and extends inside each elongated hole of the main shaft. A centering device comprising two or more sliders each moving in a radial direction, a guide hole formed in a main shaft mounting portion of the support frame, a flange formed in a corresponding main shaft portion, and the guide hole. What is claimed is: 1. A centering device comprising: a main shaft that is slidably held in the axial direction by fitting a flange into the main shaft; and a replaceable pin on the outside of the slider.