JP2000107963A - Clamp mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a clamp mechanism furnished with a brake ring which can prevent a fatigue failure, and has a durability. SOLUTION: The brake ring 6 of a clamp mechanism 1 is furnished with a flexible cylinder part 7; a ring form diaphragm 8 extending to the outer side in the radial direction continued to the end opening edge of the cylinder part 7; and a flange 9 for installing continued to the outer peripheral edge of the diaphragm 8. To the cylinder part 7, two streaks of annular projections 71 and 72 are formed. By forming the diaphragm 8 and the annular projections 71 and 72, the stress distribution when the cylinder part 7 is bent by the hydraulic pressure can be made in a gentle slope as the whole, and the maximum stress generation is also reduced. As a result, the fatigue failure of the brake ring can be prevented, and the durability is also improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a clamp mechanism used for switching a table shaft between a clamped state and an unclamped state in an indexing machine, for example.

[0002]

2. Description of the Related Art FIG. 5 shows an example of a hydraulic clamp mechanism used for an indexing machine or the like. The clamp mechanism 100 is configured between a ring-shaped table shaft 101 and a concentrically arranged ring-shaped table housing 102, and receives hydraulic pressure from outside via a hydraulic pressure supply passage 103 formed in the table housing 102. Is supplied, the table shaft 101 is clamped to the table housing 102 side, and when the hydraulic pressure is released, the table shaft 10 is clamped.
1 is returned to the unclamped state again.

FIG. 6 shows the clamp mechanism 100 on an enlarged scale. The clamp mechanism 100 includes a brake ring 110
The brake ring 110 has an annular mounting flange 111 fastened and fixed to the annular end surface 104 of the table housing 102, and extends in the direction of the central axis 101a from the inner peripheral edge 112 of the mounting flange 111. Flexible cylindrical portion 113.

[0004] The flexible cylindrical portion 113 is attached to the table shaft 10.
One circular outer peripheral surface 105 is concentrically surrounded by a slight gap. A pair of right and left O-rings 106 and 107 are mounted on the inner peripheral surface of the table housing 102 surrounding the outer periphery of the flexible cylindrical portion 113. A hydraulic chamber (pressure chamber) 120 is defined by the inner peripheral surface 108 of the table housing between the O-rings and the flexible cylindrical portion 113. It is possible to externally apply and release the hydraulic pressure to the hydraulic chamber 120 via the hydraulic supply path 103 opened on the inner peripheral surface 108. On both sides in the central axis direction of the flexible cylindrical portion 113,
Oil seals 121 and 122 are mounted respectively.

When a hydraulic pressure is externally applied to the hydraulic chamber 120 through the hydraulic supply passage 103, the pressure receiving portion of the flexible cylindrical portion 113 of the brake ring 110 that divides the hydraulic chamber 120 deflects radially inward. No. As a result, the flexible cylindrical portion 113 is pressed against the outer peripheral surface 105 of the table shaft 101.
The table shaft 101 is clamped on the table housing 102 side. When the hydraulic pressure is released, the flexible cylindrical portion 113 elastically returns, so that the table shaft 101 returns to the unlocked state again.

[0006]

In the brake ring 110 having the above-mentioned structure, stress concentration occurs in the flexible cylindrical portion 113 in the clamped state, and thus, there is a problem that fatigue fracture easily occurs. FIG. 4A shows an example in which the stress distribution of each part of the brake ring 110 is analyzed in a state where a predetermined torque is applied to the table shaft in the clamped state. The points A to F in the stress distribution curve I respectively correspond to the points A to F of the brake ring 110 shown in FIG.

As can be seen from the stress distribution curve I, the greatest stress concentration is observed at points D and E supported by the O-ring in the flexible cylindrical portion 113. Also, the mounting flange 1 in the cylindrical portion 113
At point B, which corresponds to the end of attachment 11 to the inner peripheral edge 112, the next largest stress concentration is seen. On the other hand, the stress value is greatly reduced between the point B and the point D, and almost the same stress appears in a portion between the point D and the point E, that is, a portion where the hydraulic pressure acts. I have. Further, the stress sharply decreases from the point B toward the other inner peripheral edge A of the mounting flange 111, and similarly, the stress sharply decreases from the point E toward the tip edge F of the cylindrical portion 113. are doing.

An object of the present invention is to provide a clamp device provided with a durable brake ring which does not cause fatigue failure and pays attention to such a stress distribution state of the brake ring.

[0009]

In order to solve the above-mentioned problems, the present invention provides an outer peripheral surface formed on a first member and an inner peripheral surface formed on a second member so as to surround the outer peripheral surface. A brake ring fixed to the second member and having a flexible tubular portion positioned between the outer peripheral surface and the inner peripheral surface; and a brake ring between the brake ring and the inner peripheral surface. And a pressure chamber formed in the clamping device, wherein the fluid pressure acting on the pressure chamber presses the brake ring against the outer peripheral surface to form a clamped state of the first and second members. The brake ring has the following configuration.

[0010] That is, a brake ring according to the present invention includes an annular diaphragm extending radially outward from one opening edge of the cylindrical portion, and a mounting flange continuous with the outer peripheral edge of the annular diaphragm. And the mounting flange is fixed to the second member.

In the brake ring having this structure, the annular diaphragm bends following the deformation of the flexible cylindrical portion, so that the concentration of stress generated in the flexible cylindrical portion can be reduced.
Further, the maximum stress generated can be reduced, and the stress distribution can be made gentle. As a result, fatigue breakage of the brake ring can be prevented, and its durability is also improved.

Here, the flexible tubular portion is formed with two annular convex portions formed at intervals in the axial direction thereof, and the tubular portion located between these annular convex portions is formed. It is desirable to apply a fluid pressure to the part. By increasing the thickness of the part where the maximum stress occurs in this way,
The stress generated in the portion can be reduced. Therefore, the maximum stress value generated in the brake ring can be reduced.

On the other hand, it is preferable to apply shot peening to the surface (one surface or both surfaces) of the flexible tubular portion and the annular diaphragm of the brake ring, since the fatigue strength of these portions can be improved.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a hydraulic clamp device to which the present invention is applied will be described with reference to the drawings.

FIG. 1 shows a schematic configuration of the clamp mechanism of the present embodiment. This clamp mechanism 1 is, for example, shown in FIG.
6 can be used as a crank mechanism of the indexing machine shown in FIG.

The clamp mechanism 1 has a first member, for example, a circular outer peripheral surface 3 formed on a table shaft 2 of an indexing machine. In addition, a second member, for example, an inner peripheral surface 5 formed on a table housing 4 of the indexing board is provided, and the inner peripheral surface 5 concentrically surrounds the outer peripheral surface 3 of the table shaft 2. Further, the brake ring 6 includes a flexible cylindrical portion 7 and an annular diaphragm extending radially outward from an opening edge of one end of the flexible cylindrical portion 7. 8 and an annular mounting flange 9 which is continuous with the outer peripheral edge of the diaphragm 8.

The flexible cylindrical portion 7 of the brake ring 6
The table shaft 2 faces the outer peripheral surface 3 with a slight gap. The cylindrical portion 7 has a constant thickness as a whole, but has a thick wall protruding outward in the radial direction so as to have a trapezoidal cross section at a portion adjacent to the opening at both ends. Annular convex portions 71 and 72 are formed. In the portion of the inner peripheral surface 5 of the table housing 4 which faces the annular convex portions 71 and 72, annular grooves 41 and 42 having a rectangular cross section of a predetermined depth are carved, respectively. In
O-rings 11 and 12 are mounted. Each O-ring 1
1 and 12 are annular grooves 41 and 42 of the table housing 4.
And the surfaces of the annular projections 71 and 72 of the flexible cylindrical portion 7 of the rake ring 6 are in contact with each other. A hydraulic chamber 13 is defined. A hydraulic pressure supply passage 43 formed in the table housing 4 communicates with the hydraulic chamber 13.

On the other hand, the flange 9 for mounting the brake ring 6 is formed on the annular end face 4 formed on the table housing 4.
4 is fastened and fixed by a fastening bolt (indicated by a dashed line).

When hydraulic pressure is applied to the hydraulic chamber 13 in the clamp mechanism 1 having this configuration, the flexible cylindrical portion 7 receives a pressure receiving portion 73 between the annular convex portions 71 and 72 as shown by imaginary lines in the drawing. Is bent inward in the radial direction and pressed against the outer peripheral surface 3 of the inner table shaft. As a result, the table shaft 2 is clamped on the table housing 4 side. After the clamped state, a constant torque is applied to the table shaft 2 to maintain the clamped state. To release the clamp, first release the torque and then release the hydraulic pressure. As a result, the pressure receiving portion 73 of the cylindrical portion 7 elastically returns, and the table shaft 2 returns to the unclamped state again.

The distribution of the stress generated in the brake ring 6 when the clamped state is formed by the clamp mechanism 1 having this configuration was analyzed. FIG. 3A shows the obtained stress distribution curve. The points A to F of the stress distribution curve II correspond to the points A to F of the brake ring 6 shown in FIG.

As apparent from comparison of the stress distribution curve II with the stress distribution curve I of the conventional brake ring (see FIG. 4), the generated stress is reduced as a whole. Further, the values of points D and E where the maximum stress occurs are greatly reduced. Further, no stress concentration is observed between the cylindrical portion 7 and the mounting flange 9, and the stress distribution is gentle as a whole.

Accordingly, the brake ring 6 of the present embodiment is less likely to cause fatigue failure and has improved durability as compared with a brake ring having a conventional configuration.

Here, in the brake ring 6 of the present embodiment, it is preferable to perform shot peening on the surfaces of the cylindrical portion 7 and the diaphragm 8, since their fatigue strength can be increased. Shot peening can be applied to one or both sides of these parts.

In this embodiment, the cylindrical portion 7 is formed with two annular convex portions 71 and 72. Even when this is omitted, the stress distribution becomes gentler than that of the conventional brake ring. It was confirmed that the maximum stress was also reduced.

Next, referring to FIG. 2, desirable dimensions of each part of the brake ring 6 according to the present invention will be described. According to experiments performed by the present inventors, it has been found that the following ranges are desirable as the dimensions of the cylindrical portion 7 and the diaphragm 8 of the brake ring 6.

First, the thickness t1 of the pressure receiving portion 73 of the cylindrical portion 7
Is preferably in the range of 0.2 to 0.5% of the inner diameter ΦD1 of the cylindrical portion 7.

The annular convex portions 71, 7 formed on the cylindrical portion 7
The thickness t2 of 2 is preferably 1.5 times or more the thickness t1 of the pressure receiving portion 73. Furthermore, it is desirable to set it to 1.5 to 2 times.

It is desirable that the upper and lower lengths l of the annular convex portions 71 and 72 in the trapezoidal cross-sectional shape be four times or more the thickness t1. Furthermore, it is desirable to set it within the range of 4 to 8 times.

Regarding the inclination angles on both sides in the trapezoidal cross-sectional shape of the annular convex portions 71 and 72, if the inclination angle on the pressure receiving portion 73 side is θb and the inclination angle on the opposite side is θa,
The angle θa is equal to or larger than the angle θb, and the angle θa is 7 to 2
It is desirable that the angle θb be within the range of 0 degrees and the angle θb be within the range of 5 to 20 degrees. Further, it is desirable that the angle θa be in the range of 7 to 11 degrees and the angle θb be in the range of 5 to 9 degrees.

The inner diameter ΦD2 of the mounting flange 9 is desirably in the range of 105 to 130% of the inner diameter ΦD1 of the cylindrical portion 7. In other words, it is desirable to provide an annular diaphragm 8 having a width of these diameter differences.

The cross-sectional shape of the curved portion, which is the boundary between the diaphragm 8 and the cylindrical portion 7, has a radius of curvature R of the concave side curve.
1 is set to a value within the range of at least twice the thickness t1 of the pressure-receiving portion, and preferably within a range of 2 to 3 times, and the radius of curvature R2 of the convex side curve is set to at least twice the thickness t1 of the pressure-receiving portion, preferably 3 It is desirable that the value be within a range of up to 4 times and that R1 be a value equal to or greater than R2.

In the above description, the annular convex portions 71 and 72 formed on the cylindrical portion 7 have a trapezoidal cross section, but may have a cross-sectional shape that is raised in an arc shape. Further, the protrusion may be a protrusion protruding inward in the radial direction.

Although the above description is an example of a clamp mechanism using hydraulic pressure, it is also possible to use a fluid pressure other than hydraulic pressure.

[0034]

As described above, in the clamp mechanism of the present invention, the diaphragm is formed between the flexible cylindrical portion of the brake ring and the mounting flange mounted on the fixed member. The configuration is adopted. With this diaphragm, the stress distribution generated when the cylindrical portion is bent can be made gentle as a whole, and the stress concentration can be reduced. Therefore, fatigue destruction of the brake ring can be prevented, and durability of the brake ring is also improved.

Further, in the present invention, since the annular convex portion is formed at the maximum stress generating portion in the cylindrical portion of the brake ring, the stress generated at the portion can be greatly reduced. As a result, it is possible to reliably prevent the fatigue destruction of the brake ring,
Its durability can be further improved.

Further, in the present invention, since the surface of the cylindrical portion and the surface of the diaphragm, which are the bent portion of the brake ring, are subjected to shot peening, their fatigue strength can be increased.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a clamp mechanism to which the present invention is applied.

FIG. 2 is an explanatory diagram for explaining a desirable shape of each part of a brake ring of the clamp mechanism of FIG. 1;

FIG. 3 is an explanatory diagram showing a cross-sectional shape of a bent portion of a brake ring of the clamp mechanism of FIG. 1, and a graph showing a stress distribution curve thereof.

FIG. 4 is an explanatory diagram showing a cross-sectional shape of a bent portion of a brake ring of a conventional clamp mechanism, and a graph showing a stress distribution curve thereof.

FIG. 5 is a schematic sectional view showing a main part of an indexing board provided with a conventional clamping mechanism.

FIG. 6 is an enlarged view showing the clamp mechanism of FIG. 5 in an enlarged manner.

[Explanation of symbols]

 Reference Signs List 1 clamp mechanism 2 table shaft (first member) 3 outer peripheral surface of table shaft 4 table housing (second member) 5 inner peripheral surface of table housing 6 brake ring 7 flexible cylindrical portion 71, 72 annular convex portion 73 Pressure receiving part 8 Diaphragm 9 Flange for mounting 11, 12 O-ring 13 Hydraulic chamber 43 Hydraulic supply path

Continued on the front page (72) Inventor Yoshihide Kiyosawa 1856-1, Odaka, Hodaka-cho, Minamiazumi-gun, Nagano Prefecture Inside the Harmonic Drive Systems Co., Ltd. Hotaka Plant (72) Inventor Mitsuo Yajima, Odori-maki, Hotaka-cho, Minamiazumi-gun, Nagano 1856-1 Harmonic Drive Systems Co., Ltd. Hotaka factory F-term (reference) 3C028 EE00 3C048 BB12 CC17 DD12 3J022 DA15 EA42 FA08 GA10

Claims (3)

[Claims] An outer peripheral surface formed on a first member; an inner peripheral surface formed on a second member surrounding the outer peripheral surface;
A brake ring provided between the outer peripheral surface and the inner peripheral surface and fixed to the second member and formed between the brake ring and the inner peripheral surface; A pressure chamber, wherein the brake ring is pressed against the outer peripheral surface by a fluid pressure acting on the pressure chamber to form a clamped state of the first and second members. Has an annular diaphragm extending radially outward from one opening edge of the cylindrical portion, and a mounting flange continuous to the outer peripheral edge of the annular diaphragm, wherein the mounting flange is the first flange. A clamp device fixed to the second member. 2. The flexible tubular portion according to claim 1, wherein the flexible tubular portion has two annular convex portions formed at intervals in an axial direction thereof, and is located between the annular convex portions. A fluid pressure acts on the portion of the cylindrical portion to be clamped. 3. The clamping mechanism according to claim 1, wherein the surface of the flexible tubular portion of the brake ring and the surface of the annular diaphragm are subjected to shot peening.