Clamping mechanism of rotation table device

Abstract

A clamping mechanism of rotation table device includes a shaft fixing a workpiece to an end portion thereof, a brake disk fixed to the shaft, and a clamping mechanism clamping or unclamping the brake disk by driving a piston. The clamping mechanism includes a plate spring fixed to a rear plate fixed to a casing and a piston and urging the piston in a clamping direction at all times by an elastic deformation restoring force and the plate spring is fixed to the rear plate or the piston through an annular plate.

Claims

1. A clamping mechanism of a rotation table device, wherein the rotation table device comprises: a shaft which is rotatably provided inside a casing and an end portion of which a workpiece or a jig is fixed to, and a brake disk provided on the shaft in a manner such that the brake disk cannot rotate with respect to the shaft, the clamping mechanism is configured to clamp the brake disk so that the shaft is not rotatable, and unclamp the brake disk so that the shaft is rotatable, the clamping mechanism comprises: a piston that is driven by a working fluid in a direction in which the brake disk is clamped or unclamped; and a plate spring which is fixed to (i) the piston and (ii) a rear plate fixed to the casing, and which urges the piston in the clamping or unclamping direction at all times by an elastic deformation restoring force, wherein the plate spring is fixed to any one of or both the rear plate and the piston through an annular plate.

2. The clamping mechanism according to claim 1, wherein the annular plate is provided between the plate spring and a fixing member fixing the plate spring to the piston or the rear plate.

3. The clamping mechanism of rotation table device according to claim 2, wherein the fixing member is configured as a fixing bolt, and the annular plate is provided between the plate spring and a head part of the fixing bolt.

4. The clamping mechanism according to claim 1, wherein the annular plate is provided between (i) the plate spring and (ii) the rear plate or the piston.

5. The clamping mechanism according to claim 1, wherein the plate spring is fixed to at least one of the rear plate and the piston through the annular plate provided at a fixing portion where the plate spring is fixed to the rear plate or to the piston.

6. The clamping mechanism according to claim 1, wherein the annular plate includes a first annular plate provided between the plate spring and a first fixing member fixing the plate spring to the piston, and a second annular plate provided between the plate spring and a second fixing member fixing the plate spring to the rear plate.

7. The clamping mechanism according to claim 1, wherein the annular plate includes a first annular plate provided between the plate spring and the piston, and a second annular plate provided between the plate spring and the rear plate.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The forgoing and other objects and feature of the invention will be apparent from the following description of preferred embodiments of the invention with reference to the accompanying drawings, in which:

(2) FIG. 1 is a cross-sectional view showing a face passing through a center line of a rotation table device including a direct drive mechanism with a clamping mechanism according to an embodiment of the present invention;

(3) FIG. 2 is an enlarged view showing a fixing portion of a spring disk (a plate spring) of the rotation table device shown in FIG. 1;

(4) FIGS. 3A to 3C are top views respectively showing a shape example (in a top view) of an annular plate disposed between a fixing part (a head part of a fixing bolt) and the fixing portion of the spring disk of FIG. 2;

(5) FIG. 4 shows an example in which the annular plate shown in FIG. 2 is disposed between a piston and a first fixing portion of a spring disk;

(6) FIG. 5 shows an example in which the annular plate shown in each of FIGS. 3A to 3C is disposed between a second fixing portion of a spring disk and a head part of a second fixing bolt;

(7) FIG. 6 shows an example in which the annular plate shown in each of FIGS. 3A to 3C is disposed between a second fixing portion of a spring disk and a rear plate;

(8) FIG. 7 shows an example in which the annular plate shown in each of FIGS. 3A to 3C is disposed between a first fixing portion of a spring disk and a head part of a first fixing bolt and between a second fixing portion of the spring disk and a head part of a second fixing bolt; and

(9) FIG. 8 shows another example in which the annular plate shown in each of FIGS. 3A to 3C is disposed between a first fixing portion of a spring disk and a piston and between a second fixing portion of the spring disk and a rear plate.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(10) An index rotation table device including a direct drive mechanism with a clamping mechanism according to an embodiment of the present invention will be described with reference to FIG. 1.

(11) A shaft 1 of the rotation table device is rotatably supported by a housing 3 fixed to a casing 2 through a bearing 4. A workpiece or jig (not shown) is removably fixed to the shaft at the end portion thereof. A stator 5a of a motor for rotationally driving the shaft 1 is fixed to the housing 3 and a rotor 5b of the motor is attached to the shaft 1 while being rotatably supported by the casing 2.

(12) A cylinder 7 and a rear plate 8 are also fixed to the casing 2. A brake disk 6 is sandwiched between an end face of the shaft 1 and an end face of an attachment member 14. With this configuration, the brake disk 6 is coupled to the shaft 1 so as not to be rotatable and rotates along with the shaft 1 with respect to the casing 2. The piston 9 is disposed in a groove shape formed by the cylinder 7 and the rear plate 8 fixed to the casing 2. Further, the clamping member 13 fixed to the casing 2 faces a disk face of the brake disk 6.

(13) A spring disk 10 which is a plate spring includes a first fixing portion 10a, a second fixing portion 10b, and a support portion 10c which supports the first fixing portion 10a and the second fixing portion 10b, as shown in an enlarged view of FIG. 2. In the spring disk 10, the first fixing portion 10a is fixed to the piston 9 by the first fixing bolt 12a of the fixing part and the second fixing portion 10b is fixed to the rear plate 8 by the second fixing bolt 12b. With this configuration, the rotation of the piston 9 with respect to the shaft 1 is prevented. Further, the spring disk 10 is configured to urge the brake disk 6 in a clamping direction at all times by a repelling force caused by the elastic deformation of the support portion 10c supporting the first and second fixing portions 10a and 10b. In addition, the repelling force caused by the elastic deformation of the spring disk 10 may be used to urge the brake disk 6 in an unclamping direction at all times.

(14) In the present invention, since stress concentrates on the vicinity of the fixing portion of the spring disk 10, the spring disk 10 is fixed to the piston 9 and the rear plate 8 through an annular plate 11 so that the concentration of stress is distributed.

(15) In the examples shown in FIGS. 1 and 2, the annular plate 11 is fixed while being disposed between the first fixing portion 10a of the spring disk 10 and (the head part of) the first fixing bolt 12a serving as the fixing part.

(16) The piston 9 is able to move forward and backward inside the groove-shaped space. The inside of the groove-shaped space is divided into a clamping air chamber 15a and an unclamping air chamber 15b through the piston 9 so that the piston is movable by compressed air serving as a working fluid. A control of air into these two air chambers 15a and 15b is performed by an electromagnetic valve (not shown).

(17) When a clamping instruction is input, the electromagnetic valve is operated so that the compressed air flows into the clamping air chamber 15a and the compressed air of the unclamping air chamber 15b is discharged to the outside of the unclamping air chamber 15b and the piston 9 is operated toward the brake disk 6 so that the brake disk 6 is sandwiched by the piston 9 and the clamping member 13 fixed to the casing 2. As a result, the shaft 1 becomes not rotatable.

(18) When an unclamping instruction is input, on the contrary, the electromagnetic valve is operated so that the compressed air flows into the unclamping air chamber 15b and the compressed air of the clamping air chamber 15a is discharged to the outside of the clamping air chamber 15a and the piston 9 moves in the reverse direction so that the brake disk 6 is released from the piston 9 and the clamping member 13. As a result, the shaft 1 is rotatable.

(19) Further, in the embodiment, the compressed air is used as the working fluid for driving the piston 9, but a different working fluid such as working oil may be used.

(20) The annular plate 11 is disposed between the first fixing portion 10a of the spring disk 10 and the head part of the first fixing bolt 12a as shown in FIG. 2. With this configuration, since the concentration of stress on the vicinity of the bolt of the spring disk can be distributed during a clamping or unclamping operation, it is possible to prevent a crack or plastic deformation of the first fixing portion 10a of the spring disk 10.

(21) FIGS. 3A to 3C respectively show examples of the annular plates 11 having different shapes. Each of these annular plate 11 has a plurality of holes through which a fixing part such as a fixing bolt is allowed to pass.

(22) Further, in FIG. 2, the annular plate 11 is disposed between the first fixing portion 10a of the spring disk 10 (a portion of the spring disk 10 which is fixed to the piston 9 by means of the first fixing bolt 12a) and the head part of the first fixing bolt 12a. However, instead of such configuration, the annular plate 11 may be disposed between the second fixing portion 10b of the spring disk 10 (a portion of the spring disk 10 which is fixed to the rear plate 8 by means of the second fixing bolt 12b) and the head part of the second fixing bolt 12b or between the spring disk 10 and the rear plate 8 or the piston 9 of the fixing target fixing the spring disk 10.

(23) FIG. 4 shows an example in which the annular plate 11 is disposed between the first fixing portion 10a of the spring disk 10 and the piston 9. The first fixing portion 10a of the spring disk 10 is fixed to the piston 9 by means of the first fixing bolt 12a.

(24) FIG. 5 shows an example in which the annular plate 11 is disposed between the second fixing portion 10b of the spring disk 10 and the head part of the second fixing bolt 12b. The second fixing portion 10b of the spring disk 10 is fixed to the rear plate 8 by means of the second fixing bolt 12b.

(25) FIG. 6 shows an example in which the annular plate 11 is disposed between the second fixing portion 10b of the spring disk 10 and the rear plate 8. The second fixing portion 10b of the spring disk 10 is fixed to the rear plate 8 by means of the second fixing bolt 12b.

(26) FIG. 7 shows an example in which the annular plate 11 is disposed between the first fixing portion 10a of the spring disk 10 and the head part of the first fixing bolt 12a and also between the second fixing portion 10b of the spring disk 10 and the head part of the second fixing bolt 12b. The first fixing portion 10a of the spring disk 10 is fixed to the piston 9 by means of the first fixing bolt 12a and the second fixing portion 10b is fixed to the rear plate 8 by means of the second fixing bolt 12b.

(27) FIG. 8 shows an example in which the annular plate 11 is disposed between the first fixing portion 10a of the spring disk 10 and the piston 9 and also between the second fixing portion 10b of the spring disk 10 and the rear plate 8. The first fixing portion 10a of the spring disk 10 is fixed to the piston 9 by means of the first fixing bolt 12a and the second fixing portion 10b is fixed to the rear plate 8 by means of the second fixing bolt 12b.

(28) As shown in FIGS. 2 to 8, when the annular plate 11 is disposed at any position to which the spring disk 10 is fixed, the concentration of stress on the vicinity of the fixing portion can be distributed and thus a crack or plastic deformation of the fixing portion of the spring disk 10 can be prevented.

(29) In the above-described embodiment, an example has been described in which the present invention is applied to the rotation table device of the direct drive mechanism, but the present invention can be also applied to the rotation table device of a different driving mechanism such as a driving mechanism of a worm gear structure. Further, the present invention can be also applied to the rotation table device without the driving mechanism.