WO2022044215A1

WO2022044215A1 - Hydraulic clamp device, workpiece gripping start point detection method of hydraulic clamp device, workpiece gripping start point detection device, and workpiece gripping method

Info

Publication number: WO2022044215A1
Application number: PCT/JP2020/032424
Authority: WO
Inventors: 薫直居; 正樹佐藤; 厚山田
Original assignee: 黒田精工株式会社
Priority date: 2020-08-27
Filing date: 2020-08-27
Publication date: 2022-03-03
Also published as: JP6825172B1; JPWO2022044215A1

Abstract

[Problem] To provide a hydraulic clamp device that does not need a slidable sealing part in a pressurizing part for pressurizing a working fluid in a working fluid chamber, thereby solving the occurrence of defects related to a sealing part. [Solution] A hydraulic clamp device 10 which has a body 12 provided with an outer peripheral surface 14A and a first cylindrical member 20 provided with an inner peripheral surface 20B overlapping with the outer peripheral surface 14A and in which a portion where the body 12 and the first cylindrical member 20 overlap has a recessed section 26 that defines a working fluid chamber 22, and the pressure of a working fluid sealed in the working fluid chamber 22 causes the first cylindrical member 20 to be elastically deformed to clamp a member W1 to be clamped, the hydraulic clamp device comprising: a pressurizing container 40 that defines a pressurizing chamber 32 communicating with the working fluid chamber 22 and filled with the working fluid and, by being elastically deformed, pressurizes the working fluid in the pressurizing chamber 32; and an elastic deformation-providing device 56 that elastically deforms the pressurizing container 40.

Description

Work gripping start point detection method, work gripping start point detection device and work gripping method in hydraulic clamp device, hydraulic clamp device

INDUSTRIAL APPLICABILITY The present invention detects a work gripping start point in a hydraulic clamping device and a hydraulic clamping device that clamp (hereinafter, also referred to as gripping) a member to be clamped used in the machining field and the measuring field by applying pressure to a working liquid. The present invention relates to a method, a work gripping start point detection device, and a work gripping method.

The hydraulic clamp device has a main body including a thin-walled tubular portion that defines a working liquid chamber, and a pressurizing portion that is provided in the main body and pressurizes the working liquid that is sealed in the working liquid chamber. It is known that a thin-walled tubular portion clamps a member to be clamped (hereinafter, also referred to as a work) by elastically deforming in the radial direction by applying pressure to the working liquid enclosed in the working liquid chamber. The pressurizing portion has a piston slidably provided on the main body and a working screw screw-engaged with the main body, and is a piston type that pressurizes the working liquid by advancing the piston by the screwing of the working screw ( For example, Patent Document 1).

Japanese Patent No. 6340493

The piston-type pressurizing part has a high degree of liquidtightness between the main body and the piston in order to ensure the liquidtightness of the working liquid chamber, that is, to prevent the boosted working liquid from leaking to the outside of the working liquid chamber. A seal that guarantees is required.

Since the seal part is a dynamic one that can slide with respect to the main body, it is inevitable that the sealability will deteriorate due to wear and deterioration during use, and maintenance is required. In addition, the balance between the sliding resistance of the seal portion and the elastic force of the thin-walled cylindrical portion may hinder the restoration of the thin-walled tubular portion to the original state, and the clamped member can be unclamped smoothly. It causes a problem that it is not done.

The problem to be solved by the present invention is a hydraulic clamp device that eliminates the need for a slidable seal portion in the pressurizing portion for boosting the hydraulic fluid in the hydraulic fluid chamber and eliminates the occurrence of defects caused by the seal portion. , And a method for detecting a work gripping start point, a work gripping start point detecting device, and a work gripping method in the hydraulic clamp device.

(1) In order to solve such a problem, the hydraulic clamping device according to one embodiment of the present invention includes a first member having a first peripheral surface forming an outer peripheral surface or an inner peripheral surface, and the first member. The first member has a second member having a second peripheral surface forming an inner peripheral surface or an outer peripheral surface that overlaps the peripheral surface of the above, and the first member and the second member overlap each other. A working liquid chamber is defined by a recess provided on at least one of the peripheral surface and the second peripheral surface, and the second member is elastically deformed by the pressure of the working liquid enclosed in the working liquid chamber. A hydraulic clamping device that clamps a member to be clamped, and a pressure vessel that communicates with the working liquid chamber to define a pressure chamber filled with the working liquid and pressurizes the working liquid in the pressure chamber by elastic deformation. The pressure vessel is provided with an elastic deformation imparting device that elastically deforms the pressure vessel.

According to this configuration, the working liquid in the working liquid chamber can be boosted without the need for a piston. This eliminates the need for a seal portion that inevitably slides in the pressure portion including the piston, and eliminates the occurrence of problems caused by the seal portion.

(2) In the hydraulic clamp device, preferably, the pressure vessel is integrally provided with the first member, and a part thereof is composed of the first member.

According to this configuration, the pressure vessel is simply configured.

(3) In the hydraulic clamping device, preferably, the pressure vessel includes a shaft-shaped portion of the first member and a tubular member mounted on the outer periphery of the shaft-shaped portion, and the shaft-shaped portion and the shaft-shaped portion. The pressure vessel is defined by the tubular member, and the elastic deformation imparting device engages with the outer periphery of the tubular member so as to be able to reduce the diameter, and the diameter reduction member deforms the tubular member by the diameter reduction. The hydraulic clamping device according to claim 1, wherein the first member includes an internal passage connecting the working liquid chamber and the pressure vessel.

According to this configuration, the working liquid in the working liquid chamber is boosted by the reduced diameter deformation of the tubular member of the pressure vessel. In addition, the pressure vessel is simply constructed, and communication between the working liquid chamber and the pressure chamber is reliably performed without the need for external piping.

(4) In the hydraulic clamping device, preferably, the tubular member has a portion in which the elastic modulus in the radial direction is higher than the elastic modulus in the radial direction of the portion where the second member defines the working liquid chamber. Includes.

According to this configuration, the reduced diameter deformation of the tubular member of the pressure vessel is surely and smoothly performed.

(5) In the hydraulic clamping device, preferably, the pressure vessel is attached to the end portion of the first member, and the tubular portion and the end of the tubular portion opposite to the first member. The pressure vessel is defined by the end portion of the first member and the cup-shaped member, and the elastic deformation imparting device is contracted to the outer periphery of the tubular portion, including a cup-shaped member having an end wall for closing the portion. A diameter-reducing member that engages diametrically and deforms the tubular portion by diameter reduction is included, and the first member includes an internal passage that communicates the working liquid chamber and the pressure vessel.

According to this configuration, the working liquid in the working liquid chamber is boosted by the reduced diameter deformation of the tubular member. In addition, the pressure vessel is simply constructed, and communication between the working liquid chamber and the pressure chamber is reliably performed without the need for external piping.

(6) In the hydraulic clamping device, preferably, the pressure vessel is attached to the end portion of the first member, and the tubular portion and the tubular portion including a tapered outer peripheral surface at least in a part in the axial direction. The pressure vessel is defined by a cup-shaped member having an end wall that closes an end portion of the portion opposite to the first member, and the end portion of the first member and the cup-shaped member define the pressure vessel. The elastic deformation imparting device is provided with an inner peripheral surface that is slidably fitted to the tapered outer peripheral surface in the axial direction, and the outer fitting that deforms the tubular portion by reducing the diameter due to the axial displacement with respect to the cup-shaped member. The first member includes an internal passage connecting the working liquid chamber and the pressure vessel.

(7) In the hydraulic clamping device, preferably, the tubular portion has a portion in which the elastic modulus in the radial direction is higher than the elastic modulus in the radial direction of the portion where the second member defines the working liquid chamber. Includes.

According to this configuration, the reduced diameter deformation of the cylindrical portion can be reliably and smoothly released.

(8) In the hydraulic clamping device, preferably, the pressure vessel is attached to the end portion of the first member, and the tubular portion and the end of the tubular portion opposite to the first member. The pressure vessel is defined by the end portion of the first member and the cup-shaped member, and the elastic deformation imparting device includes an axis line with respect to the cup-shaped member. Includes an axially moving member that is displaceable in the direction and deforms the end wall in the axial direction due to axial displacement, the first member having an internal passage connecting the working liquid chamber and the pressure vessel. include.

According to this configuration, the working liquid in the working liquid chamber is boosted by the deformation of the end wall in the axial direction. In addition, the pressure vessel is simply constructed, and communication between the working liquid chamber and the pressure chamber is reliably performed without the need for external piping.

(9) In the hydraulic clamping device, the first member includes a recess opened at an end, and the pressure vessel includes an end wall that closes the opening of the recess, and the end of the first member. The pressure vessel is defined by the end portion of the first member and the end wall member, and the elastic deformation imparting device can be displaced in the axial direction with respect to the end wall member. The first member includes an internal passage connecting the working liquid chamber and the pressure vessel.

According to this configuration, the working liquid in the working liquid chamber is boosted by deforming the end wall in the axial direction. In addition, the pressure vessel is simply constructed, and communication between the working liquid chamber and the pressure chamber is reliably performed without the need for external piping.

(10) The hydraulic clamping device preferably includes a portion of the end wall whose axial elastic modulus is higher than the radial elastic modulus of the portion where the second member defines the working liquid chamber. I'm out.

According to this configuration, the deformation of the end wall in the axial direction is surely and smoothly performed.

(11) The hydraulic clamping device preferably has an urging member provided between the first member and the end wall and urging in a direction for restoring axial deformation of the end wall. ..

(12) In order to solve such a problem, the work gripping start point detecting method in the hydraulic clamping device according to one embodiment of the present invention is a first method including a first peripheral surface forming an outer peripheral surface or an inner peripheral surface. It has a member and a second member having a second peripheral surface forming an inner peripheral surface or an outer peripheral surface that overlaps the first peripheral surface, and the first member and the second member overlap each other. A working liquid chamber is defined in the portion by a recess provided in at least one of the first peripheral surface and the second peripheral surface, and the second member is formed by the pressure of the working liquid sealed in the working liquid chamber. A pressure vessel that clamps the member to be clamped by elastic deformation, further defines a pressure chamber filled with the working liquid by communicating with the working liquid chamber, and pressurizes the working liquid in the pressure chamber by the elastic deformation. In a hydraulic clamping device having an elastic deformation applying device that elastically deforms the pressure vessel, the work gripping start point at the time when the second member starts abutting against the clamped member is detected. The method is to detect the work gripping start point based on the pressure change of the working liquid with respect to the driving amount of the elastic deformation imparting device.

According to this method, the work gripping start point can be accurately detected.

(13) In the work gripping start point detection method in the hydraulic clamp device, preferably, the pressure of the working liquid with respect to the driving amount of the elastic deformation imparting device in a state where the clamped member is attached to the hydraulic clamp device. The time point at which the rate of increase changes is defined as the work gripping start point.

(14) In order to solve such a problem, the work gripping method by the hydraulic clamp device according to one embodiment of the present invention is the work gripping start point detected by the work gripping start point detection method in the hydraulic clamp device. The gripping force of the clamped member is set based on the driving amount of the elastic deformation applying device or the pressure of the working liquid.

According to this method, even if the clamped member has variations in dimensions, the clamped member can be accurately gripped with a required gripping force.

(15) In order to solve such a problem, the work gripping start point detecting device in the hydraulic clamping device according to the one embodiment according to the present invention has a first peripheral surface forming an outer peripheral surface or an inner peripheral surface. It has a member and a second member having a second peripheral surface forming an inner peripheral surface or an outer peripheral surface that overlaps the first peripheral surface, and the first member and the second member overlap each other. A working liquid chamber is defined in the portion by a recess provided in at least one of the first peripheral surface and the second peripheral surface, and the second member is formed by the pressure of the working liquid sealed in the working liquid chamber. A pressure vessel that clamps the member to be clamped by elastic deformation, further defines a pressure chamber filled with the working liquid by communicating with the working liquid chamber, and pressurizes the working liquid in the pressure chamber by the elastic deformation. In a hydraulic clamping device having an elastic deformation applying device that elastically deforms the pressure vessel, the work gripping start point at the time when the second member starts abutting against the clamped member is detected. The device includes a pressure detecting device for detecting the pressure of the working liquid and an arithmetic processing device for detecting the work gripping start point based on the change in the pressure with respect to the driving amount of the elastic deformation applying device.

According to this configuration, the work gripping start point can be accurately detected.

According to the hydraulic clamping device according to the present invention, it becomes pistonless, and the sealing portion inevitably sliding in the pressurizing portion for boosting the working liquid in the working liquid chamber becomes unnecessary, which is caused by the sealing portion. The occurrence of problems is resolved.

A vertical sectional view showing the first embodiment of the hydraulic clamp device according to the present invention. Sectional drawing along line II-II of FIG. The block diagram which shows the work gripping start point detection device in the hydraulic clamp device which concerns on Embodiment 1. A graph showing the relationship between the bolt rotation amount (diameter reduction amount) and the hydraulic pressure (pressure) of the working liquid in the hydraulic clamp device according to the first embodiment. A vertical sectional view showing the second embodiment of the hydraulic clamp device according to the present invention. Longitudinal sectional view showing Embodiment 3 of the hydraulic clamp device according to the present invention. Longitudinal sectional view showing Embodiment 4 of the hydraulic clamp device according to the present invention. Longitudinal sectional view showing Embodiment 5 of the hydraulic clamp device according to the present invention.

Hereinafter, embodiments of the present invention will be described.

[Embodiment 1]
Embodiment 1 of the present invention will be described with reference to FIGS. 1 and 2.

The hydraulic clamp device 10 of the first embodiment is a mandrel type and has a main body (first member) 12. The main body 12 has a first axial portion 14, a flange portion 16, and a second axial portion 18 having a circular cross section (cross section orthogonal to the central axis) on the same axis in order in the axial direction. The first axial portion 14 and the second axial portion 18 have the same outer diameter. The flange portion 16 has an outer diameter larger than that of the first axial portion 14 and the second axial portion 18, and extends outward in the radial direction with respect to the first axial portion 14 and the second axial portion 18. It is formed.

A first cylindrical member (second member) 20 having an annular cross-sectional shape forming a wall body having a thin wall structure is fitted on the outer periphery of the first axial portion 14. The first tubular member 20 is a cylindrical wall body that defines the working liquid chamber 22 on the inner surface side, and has an outer peripheral surface (clamping surface) 20A and a first axial portion 14 that clamp the cylindrical member to be clamped W1. The inner peripheral surface (second peripheral surface) 20B fitted to the outer peripheral surface (first peripheral surface) 14A of the above is provided. The first tubular member 20 has one end surface abutted against one end surface of the flange portion 16 and the other end surface abuts on one end surface of the snap ring 24 mounted on the first axial portion 14. , Is fixed to the first axial portion 14 so as not to move in the axial direction. The fixing of the first cylindrical member 20 to the outer periphery of the first shaft-shaped portion 14 may be performed by another method such as press fitting or adhesion.

A circumferential groove-shaped recess 26 is formed on the outer peripheral surface 14A of the first axial portion 14. The first axial portion 14 and the first tubular member 20 have a cross-sectional shape extending over the entire circumference of the outer peripheral surface 14A of the first axial portion 14 by a recess 26 in a portion that overlaps each other in the radial direction. An annular working liquid chamber 22 is defined.

Thus, the first tubular member 20 defines the working liquid chamber 22 on the inner surface side and the clamp surface (outer peripheral surface 20A) on the outer surface side.

On the outer peripheral surface 14A of the first axial portion 14, O-rings 28 for ensuring the liquidtightness of the working liquid chamber 22 are mounted on both sides of the working liquid chamber 22 in the axial direction. The first cylindrical member 20 may be liquidtightly joined to the first shaft-shaped portion 14 by brazing or the like. In this case, the O-ring 28 may be omitted.

A second cylindrical member 30 having an annular cross-sectional shape forming a thin-walled wall is fitted on the outer periphery of the second axial portion 18. The second tubular member 30 is a cylindrical wall body that defines the pressure chamber 32 on the inner surface side, and includes an outer peripheral surface 30A and an inner peripheral surface 30B that fits into the outer peripheral surface 18A of the second axial portion 18. The second tubular member 30 has one end face abutted against the other end face of the flange portion 16 and the other end face abuts against one end face of the snap ring 34 mounted on the second axial portion 18. , Is fixed to the second axial portion 18 so as not to move in the axial direction.

A circumferential groove-shaped recess 36 is formed on the outer peripheral surface 18A of the second shaft-shaped portion 18. The second axial portion 18 and the second tubular member 30 have a cross-sectional shape extending over the entire circumference of the outer peripheral surface 18A of the second axial portion 18 by a recess 36 in a portion that overlaps each other in the radial direction. An annular pressure chamber 32 is defined.

Thus, the second axial portion 18 and the second tubular member 30 cooperate with each other to form a pressure vessel 40 having a closed structure that defines the pressure chamber 32. That is, the pressure vessel 40 defines the pressure chamber 32 by the second shaft-shaped portion 18 and the second tubular member 30. As a result, the pressure vessel 40 is integrally provided on the main body 12, and a part thereof is composed of the second shaft-shaped portion 18. The second tubular member 30 has a larger wall thickness than the first tubular member 20, and the radial elastic modulus of the second tubular member 30 is the portion where the first tubular member 20 defines the working liquid chamber 22. Higher than the radial modulus.

On the outer peripheral surface 18A of the second axial portion 18, O-rings 38 for ensuring the liquidtightness of the pressure chamber 32 are mounted on both sides of the pressure chamber 32 in the axial direction. The second cylindrical member 30 may be liquidtightly joined to the second shaft-shaped portion 18 by brazing or the like. In this case, the O-ring 38 may be omitted.

The main body 12 includes

internal passages

42, 44 and 46 that communicate the working liquid chamber 22 and the pressure chamber 32 with each other. The internal passage 42 extends in the axial direction at the center of the main body 12, and both ends thereof are closed by the steel balls 48. Each steel ball 48 is pressed against the tapered surface around the internal passage 42 by the screwing of the set screw 50 screw-engaged with the main body 12, so that the end portion of the internal passage 42 is closed in a liquid-tight manner. The internal passage 44 extends in the radial direction and connects the internal passage 42 and the working liquid chamber 22 in communication with each other. The internal passage 46 extends in the radial direction and connects the internal passage 42 and the pressure chamber 32 in communication with each other.

The hydraulic fluid chamber 22, the pressure chamber 32, and the

internal passages

42, 44, and 46 are filled, sealed, or sealed with hydraulic oil, which is a hydraulic fluid. That is, the hydraulic fluid chamber 22, the pressure chamber 32, and the

internal passages

42, 44, and 46 are filled with hydraulic oil.

One of the sealing portions by the steel ball 48 includes a piston structure portion for adjusting the amount of hydraulic oil and the initial pressure in the hydraulic fluid chamber 22, the pressure chamber 32 and the

internal passages

42, 44 and 46. May be good. The sealed portion of the piston structure slides when the amount of hydraulic oil and the initial pressure are adjusted, but it does not slide when the clamped member W1 is clamped or unclamped, so that the clamped member W1 is unclamped. It does not cause problems such as improper operation.

A diameter reduction member 52 is engaged with the outer circumference of the second tubular member 30 so as to be able to reduce the diameter. As shown in FIG. 2, the diameter-reducing member 52 is composed of a C ring having an opening (discontinuous portion) 52A, and the opening 52A is deformed by reducing the diameter as seen in FIG. 2 in the vertical direction. .. A bolt through hole 52B is formed at one end of the diameter reduction member 52 on the opening 52A side. A screw hole 52C is formed at the other end of the reduced diameter member 52 on the opening 52A side. An actuating bolt 54 is inserted into the bolt through hole 52B. The actuating bolt 54 reduces the diameter-reducing member 52 by reducing the vertical distance between the openings 52A by screwing. Due to the reduced diameter deformation of the reduced diameter member 52, the second tubular member 30 is reduced in diameter under elastic deformation.

That is, the diameter-reducing member 52 engages with the outer periphery of the second tubular member 30 so as to be able to reduce the diameter, and the second tubular member 30 is deformed by the diameter reduction.

Thus, the diameter-reducing member 52 and the operating bolt 54 constitute an elastic deformation applying device 56 that deforms the second tubular member 30 in diameter.

Due to the reduced diameter deformation of the second tubular member 30, the volume of the pressure chamber 32 decreases, and the pressure of the hydraulic oil in the pressure chamber 32 increases accordingly. The pressure increase of the hydraulic oil in the pressure chamber 32 propagates to the hydraulic fluid chamber 22 through the

internal passages

42, 44 and 46, and the pressure of the hydraulic oil in the hydraulic fluid chamber 22 rises.

The pressure increase of the hydraulic oil in the hydraulic fluid chamber 22 causes the first tubular member 20 to expand its diameter outward in the radial direction under elastic deformation. As a result, the outer peripheral surface 20A of the first tubular member 20 comes into contact with the inner peripheral surface of the central hole A of the clamped member (work) W1 and is pressed against the inner peripheral surface to clamp the clamped member W1. Is done. That is, the clamped member W1 has a central hole A that fits on the outer periphery of the first tubular member 20, and the first tubular shape is formed on the inner peripheral surface of the central hole A due to the enlarged diameter deformation of the first tubular member 20. When the outer peripheral surface 20A of the member 20 is in close contact with the member 20, the member 20 is gripped (clamped) by the hydraulic clamping device 10.

When the diameter-reduced deformation of the second tubular member 30 is released when the clamped member W1 is unclamped, the elastic modulus in the radial direction of the second tubular member 30 is set to the working liquid chamber of the first tubular member 20. By being higher than the elastic modulus in the radial direction of the portion defining 22, the second tubular member 30 is surely restored to the original state with a higher repulsive force than the first tubular member 20, and the first tubular member 30 is restored. 20 is surely restored to the original state. That is, the reduction deformation of the second tubular member 30 is surely and smoothly performed. As a result, the depressurization of the hydraulic oil in the hydraulic fluid chamber 22 is surely and smoothly performed, and the unclamping of the clamped member W1 is smoothly and surely performed.

Since the hydraulic clamping device 10 of the present embodiment pressurizes the hydraulic oil in the hydraulic fluid chamber 22 by elastic deformation of the second tubular member 30 of the pressure vessel 40, the pressurizing portion of the hydraulic oil is like a piston. The sliding part disappears. That is, since the hydraulic clamp device 10 is pistonless and does not require a piston, there is no sealing portion of the sliding portion of the piston, and a problem caused by the sealing portion does not occur. Further, the balance between the sliding resistance of the seal portion and the elastic force of the thin-walled tubular portion does not cause a problem that the thin-walled tubular portion is prevented from being restored to the original state, and the clamped member W1 can be used. Unclamping is done smoothly.

According to the hydraulic clamping device 10, since a part of the pressure vessel 40 is composed of the main body 12, the pressure vessel 40 is simply configured and the communication between the working liquid chamber 22 and the pressure chamber 32 requires an external pipe. It is surely done without.

The radial elastic modulus of the second tubular member 30 is higher than the radial elastic modulus of the portion where the first tubular member 20 defines the working liquid chamber 22, so that the first tubular member constituting the clamp portion is formed. The wall thickness of 20 can be reduced, and as a result, the merit of increasing the amount of diameter expansion of the clamped member W1 and the first tubular member 20 at low pressure can be obtained.

A pressure sensor 60, which is a pressure detection device, is attached to the flange portion 16. The pressure sensor 60 applies the pressure of the hydraulic oil in the hydraulic fluid chamber 22 and the pressure chamber 32 by the internal passage 62 formed in the main body 12, and measures the pressure of the hydraulic oil. The pressure of the hydraulic oil in the hydraulic fluid chamber 22 and the pressure of the hydraulic oil in the pressure chamber 32 are the same pressure. The pressure sensor 60 is of a wireless communication type, and transmits measurement value data to a wireless reader 64 arranged in the vicinity of the hydraulic clamp device 10.

Next, embodiments of the work gripping start point detection device, the work gripping start point detection method, and the work gripping method in gripping the clamped member W1 using the hydraulic clamping device 10 will be described with reference to FIGS. 2 and 3. do.

As shown in FIG. 2, the working bolt 54 is screwed by an electric tool 72 that is rotationally driven by an electric motor 70. A rotation angle sensor 74 that measures the rotation angle (rotation amount) of the operating bolt 54 by the tool 72 based on the rotation angle of the motor is connected to the electric motor 70.

As shown in FIG. 3, the work gripping start point detecting device has an electronically controlled arithmetic processing unit 76 including a microcomputer. The arithmetic processing device 76 inputs a signal (measurement data) indicating the pressure of the hydraulic oil in the working liquid chamber 22 from the pressure sensor 60 of the hydraulic clamping device 10, and the rotation amount of the working bolt 54 from the rotation angle sensor 74, in other words. A signal (measurement data) indicating the amount of screwing of the working bolt 54 is input, and the working liquid chamber 22 with respect to the amount of rotation of the working bolt 54, that is, the driving amount of the elastic deformation imparting device 56, is driven by the rotation of the electric motor 70. The work gripping start point is detected based on the pressure change of the hydraulic oil.

The work gripping start point referred to here is the amount of rotation of the working bolt 54 and the working liquid chamber 22 at the time when the outer peripheral surface 20A of the first tubular member 20 starts abutting against the inner peripheral surface of the clamped member W1. Specified by hydraulic oil pressure.

Therefore, the detection of the work gripping start point by the arithmetic processing device 76 for detecting the work gripping start point is based on the pressure change of the hydraulic oil in the hydraulic fluid chamber 22 with respect to the rotation amount of the working bolt 54, and the first tubular member 20 is detected. By specifying the time when the outer peripheral surface 20A of the outer peripheral surface 20A starts to contact the inner peripheral surface of the clamped member W1, the rotation amount of the working bolt 54 and the pressure of the hydraulic oil in the working liquid chamber 22 at that time are detected. be. The detection result of the work gripping start point is displayed on the monitor 78 connected to the arithmetic processing unit 76.

The detection of the work gripping start point by the arithmetic processing unit 76 is performed by any one of the embodiments (A) to (C) or a combination thereof.

(A) The work gripping start point is a time point at which the pressure increase rate of the hydraulic oil in the hydraulic fluid chamber 22 with respect to the rotation amount of the hydraulic bolt 54 changes with the clamped member W1 attached to the hydraulic clamping device 10.

(B) The amount of rotation of the working bolt 54 and the working liquid chamber in the threaded section of the working bolt 54, which is presumed that the outer peripheral surface 20A of the first tubular member 20 does not abut against the inner peripheral surface of the clamped member W1. The equation (Equation 1) showing the relationship with the pressure of the hydraulic oil of 22 and the working bolt 54 presumed that the outer peripheral surface 20A of the first tubular member 20 abuts on the inner peripheral surface of the clamped member W1. The solution of the simultaneous equation by the equation (Equation 2) showing the relationship between the rotation amount of the working bolt 54 in the screwing section and the pressure of the hydraulic oil in the working liquid chamber 22 is set as the work gripping start point.

Assuming that the amount of rotation of the working bolt 54 is X and the pressure of the hydraulic oil in the working liquid chamber 22 is Y, (formula 1) is represented by Y = mX + A, and (formula 2) is represented by Y = nX + B. However, A and B are intercepts, respectively.

M and n in (Equation 1) and (Equation 2) are proportional constants, and m <n. The proportionality constants m and n correspond to the slopes of the straight lines according to the straight line data of the sections a and b of the graph shown in FIG. The solution of the simultaneous equations according to (Equation 1) and (Equation 2) is the intersection C of two straight lines. The intersection C of the two straight lines corresponds to the work gripping start point.

The spiraling section of the operating bolt 54 in which the outer peripheral surface 20A of the first tubular member 20 does not abut against the inner peripheral surface of the clamped member W1 and the outer peripheral surface 20A of the first tubular member 20 are inside the clamped member W1. When the tolerance of the clamped member W1 is known, the estimation of the threading section of the actuating bolt 54 that abuts on the peripheral surface can be estimated in consideration of the tolerance.

That is, the spiraling section of the operating bolt 54 in which the outer peripheral surface 20A of the first tubular member 20 does not abut against the inner peripheral surface of the clamped member W1 is the outer peripheral surface 20A of the first tubular member 20 from the initial position. The section up to the position where the outer diameter of the member expands to the outer diameter corresponding to the lower limit of the tolerance of the member W1 to be clamped. The threaded section of the working bolt 54 in which the outer peripheral surface 20A of the first tubular member 20 abuts on the inner peripheral surface of the clamped member W1 expands to an outer diameter corresponding to the lower limit of the tolerance of the clamped member W1. The section from the position to the position where the outer diameter of the outer peripheral surface 20A is the maximum allowable value.

(C) The pressure change of the hydraulic oil in the working liquid chamber 22 with respect to the rotation amount of the working bolt 54 in the state where the clamped member W1 is not attached to the hydraulic clamping device 10, and the clamped member W1 is attached to the hydraulic clamping device 10. The work gripping start point is detected from the mutual difference between the pressure change of the hydraulic oil in the hydraulic fluid chamber 22 with respect to the rotation amount of the hydraulic bolt 54 in the state of being in the state.

In the embodiment (C), similarly to the embodiment (B), the pressure of the hydraulic oil in the hydraulic fluid chamber 22 with respect to the rotation amount of the hydraulic bolt 54 in a state where the clamped member W2 is not attached to the hydraulic clamping device 10. An equation (Equation 1) showing the relationship and an equation (Equation 2) showing the relationship between the rotation amount of the working bolt 54 in the state where the clamped member W1 is attached to the hydraulic clamping device 10 and the pressure of the hydraulic oil in the working liquid chamber 22. ) Is the solution of the simultaneous equations as the work gripping start point.

In the embodiment (C), as compared with the embodiment (B), the rotation amount of the working bolt 54 and the hydraulic oil of the working liquid chamber 22 in the state where the clamped member W1 is not attached to the hydraulic clamping device 10 and in the state where the clamped member W1 is attached are respectively. Since the section having a large relationship with the pressure of is large, it can be expected that the detection accuracy of the work gripping start point is improved as compared with the embodiment (B).

The work gripping method according to the present embodiment is carried out in the following manner after the work gripping start point detection work described above.

With the work gripping start point (the amount of rotation of the working bolt 54 and the pressure of the hydraulic oil in the working liquid chamber 22) monitored and displayed, the diameter reduction member 52 is returned to the initial position, and the clamped member W1 is placed in the hydraulic clamping device 10. In the attached state, the pressure of the hydraulic oil in the hydraulic fluid chamber 22 at the work gripping start point is the work required for the pressure of the hydraulic oil in the hydraulic fluid chamber 22 at the work gripping start point by the screwing of the working bolt 54 by the tool 72. The pressure of the hydraulic oil is increased under the supervision of a monitor display or the like until the gripping force reaches the value obtained by adding the necessary pressure.

This completes the work gripping start point detection and the work gripping setup. The hydraulic clamp device 10 for which the setup has been completed is attached to a chuck device or the like of a machine tool while holding the clamped member W1.

That is, in the work gripping method according to the present embodiment, the gripping force of the clamped member W1 is set based on the pressure of the hydraulic oil in the hydraulic fluid chamber 22 at the work gripping start point detected by the work gripping start point detection method described above. do. Even if the gripping force of the member to be clamped W1 is set based on the driving amount of the elastic deformation applying device (rotation amount of the working bolt 54) instead of the pressure of the hydraulic oil in the working liquid chamber 22 at the work gripping start point. good.

According to the work gripping method described above, even if the clamped member W1 has variations in dimensions, the clamped member W1 can be accurately gripped with a required gripping force.

[Embodiment 2]
Next, the hydraulic clamp device 80 of the second embodiment will be described with reference to FIG. In FIG. 5, the portion corresponding to FIG. 1 is designated by the same reference numeral as that shown in FIG. 1, and the description thereof will be omitted.

The hydraulic clamp device 80 is a mandrel type. The hydraulic clamp device 80 has a cup-shaped member 82 joined to the second shaft-shaped portion 18 by brazing or the like. The cup-shaped member 82 has a cylindrical portion 84 having a circular cross-sectional shape and an end wall 86 that closes an end portion of the tubular portion 84 opposite to the second axial portion 18, and the second axial portion 18 and the tubular portion 18. Together they define the pressure chamber 32. In other words, the pressure vessel 40 includes the end portion of the second shaft-shaped portion 18 and the cup-shaped member 82, and the pressure chamber 32 is defined by the end portion of the second shaft-shaped portion 18 and the cup-shaped member 82. The pressure chamber 32 communicates with the working liquid chamber 22 by

internal passages

42 and 44.

An elastic deformation applying device 56 using a diameter reducing member 52 and an operating bolt 54 is mounted on the outer peripheral surface 84A of the tubular portion 84. The elastic deformation imparting device 56 deforms the tubular portion 84 in a reduced diameter (elastic deformation) as in the first embodiment.

Due to the reduced diameter deformation of the tubular portion 84 by the elastic deformation imparting device 56, the volume of the pressure chamber 32 decreases and the pressure rises in the hydraulic oil of the pressure chamber 32 accordingly, as in the first embodiment. The pressure increase of the hydraulic oil in the pressure chamber 32 propagates to the hydraulic fluid chamber 22 through the

internal passages

42 and 44, and the pressure of the hydraulic oil in the hydraulic fluid chamber 22 rises. By increasing the pressure of the hydraulic oil in the hydraulic fluid chamber 22, the first tubular member 20 is radially expanded and deformed, and the clamped member W1 is clamped.

Since the hydraulic clamp device 80 of the present embodiment also pressurizes the hydraulic oil in the hydraulic fluid chamber 22 by elastic deformation of the tubular portion 84 of the pressure vessel 40, it slides like a piston on the pressurized portion to be pressurized by the hydraulic oil. The part no longer exists. That is, since the hydraulic clamp device 80 is pistonless, there is no sealing portion of the sliding portion of the piston, and a problem caused by the sealing portion does not occur. Further, the balance between the sliding resistance of the seal portion and the elastic force of the thin-walled tubular portion does not cause a problem that the thin-walled tubular portion is prevented from being restored to the original state, and the clamped member W1 can be used. Unclamping is done smoothly.

The radial elastic modulus of the tubular portion 84 is higher than the radial elastic modulus of the portion where the first tubular member 20 defines the working liquid chamber 22 for reliable restoration of the tubular portion 84. As a result, at the time of unclamping, the reduced diameter deformation of the cylindrical portion 84 is surely and smoothly performed. As a result, the depressurization of the hydraulic oil in the hydraulic fluid chamber 22 is surely and smoothly performed, and the unclamping of the clamped member W1 is smoothly and surely performed under the reduced diameter deformation of the first tubular member 20.

The radial elastic modulus of the tubular portion 84 is higher than the radial elastic modulus of the portion where the first tubular member 20 defines the working liquid chamber 22, so that the first tubular member 20 constituting the clamp portion The wall thickness can be reduced, and as a result, the merit of increasing the diameter expansion amount of the clamped member W1 and the first tubular member 20 at low pressure can be obtained.

Even in the hydraulic clamping device 80, since a part of the pressure vessel 40 is composed of the main body 12, the pressure vessel 40 is simply configured and the communication between the working liquid chamber 22 and the pressure chamber 32 requires an external pipe. It is surely done without doing.

Also in the hydraulic clamping device 80, the above-mentioned is performed based on the measurement of the hydraulic pressure of the working liquid chamber 22 and the rotation amount of the working bolt 54 (see FIG. 1) (driving amount of the elastic deformation imparting device 56) by the pressure sensor 60. The work gripping start point can be detected and the work can be gripped by the same method as the work gripping start point detection method and the work gripping method in the hydraulic clamping device 10.

Also in this embodiment, the gripping force of the member to be clamped W1 is determined based on the pressure of the hydraulic oil in the hydraulic fluid chamber 22 at the work gripping start point detected by the work gripping start point detection method or the rotation amount of the working bolt 54. Can be set.

[Embodiment 3]
Next, the hydraulic clamp device 90 of the third embodiment will be described with reference to FIG. In FIG. 6, the portion corresponding to FIG. 1 is designated by the same reference numeral as that shown in FIG. 1, and the description thereof will be omitted.

The hydraulic clamp device 90 is a mandrel type. The hydraulic clamp device 90 has a cup-shaped member 92 joined to the second shaft-shaped portion 18 by brazing or the like. The cup-shaped member 92 has a cylindrical portion 94 having a circular cross-sectional shape and an end wall 96 that closes an end portion of the tubular portion 94 opposite to the second axial portion 18, with the second axial portion 18. Together they define the pressure chamber 32. In other words, the pressure vessel 40 includes the end portion of the second shaft-shaped portion 18 and the cup-shaped member 92, and the pressure chamber 32 is defined by the end portion of the second shaft-shaped portion 18 and the cup-shaped member 92. The pressure chamber 32 communicates with the working liquid chamber 22 by

internal passages

42 and 44.

The tubular portion 94 has a tapered outer peripheral surface 94B formed over a predetermined axial length at an intermediate portion in the axial direction of the outer peripheral surface 94A. The tapered outer peripheral surface 94B has a tapered shape in which the outer diameter increases toward the end of the second axial portion 18 from the side of the end wall 96. The outer peripheral surface 94A is a straight outer peripheral surface whose outer diameter does not change except for the tapered outer peripheral surface 94B.

A cup-shaped outer fitting member 98 constituting the elastic deformation imparting device is provided on the outside of the tubular portion 94. The outer fitting member 98 has a circular cross-sectional shape with a straight inner peripheral surface 100A that is slidably fitted to the outer peripheral surface 94A of the tubular portion 94 in the axial direction, and is opposite to the cylindrical portion 100 and the cup-shaped member 92. Has an end wall 102 that closes the end of the. In the outer fitting member 98, the inner peripheral surface 100A is in sliding contact with the tapered outer peripheral surface 94B due to the axial displacement to the right (the side of the cup-shaped member 92) with respect to the cup-shaped member 92, and the outer peripheral surface is tapered. By applying a radial component force to the surface 94B, the tubular portion 94 is deformed in diameter.

Between the end wall 96 of the cup-shaped member 92 and the end wall 102 of the outer fitting member 98, the compression coil spring 103 that urges the outer fitting member 98 to the left with respect to the cup-shaped member 92 in the figure. Is provided. The compression coil spring 103 can be replaced with a disc spring or the like.

A linear actuator 104 of an electric type, a fluid pressure type, or the like is arranged outside the outer fitting member 98. The linear actuator 104 is an elastic deformation imparting device, has a push rod 106 that can be displaced in the axial direction as an axial movement member, and the outer fitting member 98 is displaced against the compression coil spring 103 by the push rod 106. Move to the right in the axial direction. The linear actuator 104 is provided with a linear scale 108 that measures the amount of movement of the push rod 106 in the axial direction.

The tubular portion 94 is moved in the axial direction to the right of the outer fitting member 98 by the linear actuator 104, so that the tubular portion 94 is in the axial direction of the inner peripheral surface 100A of the outer fitting member 98 with respect to the tapered outer peripheral surface 94B of the cup-shaped member 92. Due to sliding, diameter reduction deformation (elastic deformation) occurs.

Due to the reduced diameter deformation of the tubular portion 94, the volume of the pressure chamber 32 decreases and the pressure of the hydraulic oil in the pressure chamber 32 increases accordingly, as in the first embodiment. The pressure increase of the hydraulic oil in the pressure chamber 32 propagates to the hydraulic fluid chamber 22 through the

internal passages

Since the hydraulic clamp device 90 of the present embodiment also pressurizes the hydraulic oil in the hydraulic fluid chamber 22 by elastic deformation of the tubular portion 94 of the pressure vessel 40, it slides like a piston on the pressurized portion to be pressurized by the hydraulic oil. The part no longer exists. That is, since the hydraulic clamp device 90 is pistonless, there is no sealing portion of the sliding portion of the piston, and a problem caused by the sealing portion does not occur. Further, the balance between the sliding resistance of the seal portion and the elastic force of the thin-walled tubular portion does not cause a problem that the thin-walled tubular portion is prevented from being restored to the original state, and the clamped member W1 can be used. Unclamping is done smoothly.

Further, since the outer fitting member 98 is urged in the return direction by the spring force of the compression coil spring 103, the tubular portion 94 by the outer fitting member 98 is surely and smoothly released from the reduced diameter deformation at the time of unclamping. It is done in. As a result, the depressurization of the hydraulic oil in the hydraulic fluid chamber 22 is surely and smoothly performed, and the unclamping of the clamped member W1 is surely and smoothly performed.

The radial elastic modulus of the tubular portion 94 is higher than the radial elastic modulus of the portion where the first tubular member 20 defines the working liquid chamber 22 for reliable restoration of the tubular portion 94. Also by this, at the time of unclamping, the reduced diameter deformation of the cylindrical portion 94 is surely and smoothly performed. As a result, the depressurization of the hydraulic oil in the hydraulic fluid chamber 22 is surely and smoothly performed, and the unclamping of the clamped member W1 is smoothly and surely performed under the reduced diameter deformation of the first tubular member 20.

The radial elastic modulus of the tubular portion 94 is higher than the radial elastic modulus of the portion where the first tubular member 20 defines the working liquid chamber 22, so that the first tubular member 20 constituting the clamp portion The wall thickness can be reduced, and as a result, the merit of increasing the diameter expansion amount of the clamped member W1 and the first tubular member 20 at low pressure can be obtained.

Even in the hydraulic clamping device 90, since a part of the pressure vessel 40 is composed of the main body 12, the pressure vessel 40 is simply configured and the communication between the working liquid chamber 22 and the pressure chamber 32 requires an external pipe. It is surely done without doing.

In the hydraulic clamping device 90, the above-mentioned is performed based on the measurement of the hydraulic pressure of the working liquid chamber 22 by the pressure sensor 60 and the axial movement amount (driving amount of the elastic deformation imparting device) of the push rod 106 by the linear scale 108. The work gripping start point can be detected and the work can be gripped by the same method as the work gripping start point detection method and the work gripping method in the hydraulic clamping device 10.

In this embodiment, the amount of rotation on the horizontal axis in FIG. 4 is replaced with the amount of movement in the axial direction, and the arithmetic processing unit 76 in FIG. 3 uses the measured value of the amount of movement in the axial direction of the push rod 106 instead of the measured value of the amount of rotation. Should be entered.

In this embodiment, the clamped member W1 is gripped based on the pressure of the hydraulic oil in the working liquid chamber 22 at the work gripping start point detected by the work gripping start point detection method or the axial movement amount of the push rod 106. The force can be set.

[Embodiment 4]
Next, the hydraulic clamp device 110 of the fourth embodiment will be described with reference to FIG. 7. In FIG. 7, the portion corresponding to FIG. 1 is designated by the same reference numeral as that shown in FIG. 1, and the description thereof will be omitted.

The hydraulic clamp device 110 is a mandrel type. The hydraulic clamp device 110 has a cup-shaped member 112 joined to the second shaft-shaped portion 18 by brazing or the like. The cup-shaped member 112 has a cylindrical portion 114 having a circular cross-sectional shape and an end wall 116 that closes an end portion of the tubular portion 114 opposite to the second axial portion 18, with the second axial portion 18. Together they define the pressure chamber 32. In other words, the pressure vessel 40 includes an end portion of the second shaft-shaped portion 18 and a cup-shaped member 112, and the pressure chamber 32 is defined by the end portion of the second shaft-shaped portion 18 and the cup-shaped member 112. The pressure chamber 32 communicates with the working liquid chamber 22 by

internal passages

42 and 44.

The end wall 116 has a base portion 116A provided in the central portion and an annular thin-walled portion 116B extending between the base portion 116A and the tubular portion 114. The thin-walled portion 116B has a lower flexural rigidity than the base portion 116A, and is easily elastically deformed in the axial direction. By elastically deforming the thin portion 116B to the right in the figure in the axial direction, the volume of the pressure chamber 32 is reduced and the pressure of the hydraulic oil in the pressure chamber 32 is increased.

The pressure increase of the hydraulic oil in the pressure chamber 32 propagates to the hydraulic fluid chamber 22 through the

internal passages

A compression coil spring 128 is provided between the base portion 116A and the second axial portion 18 to urge the end wall 116 to the left with respect to the second axial portion 18 in the figure. The compression coil spring 128 can be replaced with a disc spring or the like.

A cup-shaped base 118 is attached to the cup-shaped member 112. The base 118 has a circular cross-sectional shape of the tubular portion 120 joined to the outer end of the tubular portion 114 of the cup-shaped member 112 by brazing or the like, and the cylindrical portion 120 on the opposite side of the cup-shaped member 112. It has an end wall 122 that closes the end.

A screw hole 124 is formed through the end wall 122 in the axial direction. An actuating bolt 126 that can be displaced in the axial direction is screw-engaged in the screw hole 124 as an axially moving member of an elastic deformation applying device that elastically deforms the thin portion 116B of the end wall 116 in the axial direction. The actuating bolt 126 abuts on the base 116A of the end wall 116 and presses the base 116A by screwing to elastically deform the thin portion 116B to the right in the drawing in the axial direction. The actuating bolt 126 is rotationally driven by an electric tool (not shown) similar to the electric tool 72 of the first embodiment, and is screwed to the right in the figure.

Since the hydraulic clamp device 110 of the present embodiment pressurizes the hydraulic oil in the hydraulic fluid chamber 22 by elastic deformation of the thin-walled portion 116B of the pressure vessel 40, a sliding portion such as a piston is applied to the pressurized portion to be pressurized by the hydraulic oil. Does not exist. That is, since the hydraulic clamp device 110 is pistonless, there is no sealing portion of the sliding portion of the piston, and a problem caused by the sealing portion does not occur. Further, the balance between the sliding resistance of the seal portion and the elastic force of the thin-walled tubular portion does not cause a problem that the thin-walled tubular portion is prevented from being restored to the original state, and the clamped member W1 can be used. Unclamping is done smoothly.

Further, since the elastic deformation of the thin wall portion 116B is released by the spring force of the compression coil spring 128, the elastic deformation of the thin wall portion 116B in the axial direction is surely and smoothly released at the time of unclamping. Will be. As a result, the depressurization of the hydraulic oil in the hydraulic fluid chamber 22 is surely and smoothly performed, and the unclamping of the clamped member W1 is surely and smoothly performed.

The elastic modulus in the axial direction of the end wall 116 including the thin-walled portion 116B is higher than the elastic modulus in the radial direction of the portion where the first tubular member 20 defines the working liquid chamber 22. Also by this, at the time of unclamping, the elastic deformation in the axial direction of the thin-walled portion 116B is surely and smoothly released. As a result, the depressurization of the hydraulic oil in the hydraulic fluid chamber 22 is surely and smoothly performed, and the unclamping of the clamped member W1 is smoothly and surely performed under the reduced diameter deformation of the first tubular member 20.

The elastic modulus in the axial direction of the end wall 116 including the thin-walled portion 116B is higher than the elastic modulus in the radial direction of the portion where the first tubular member 20 defines the working liquid chamber 22, so that the first cylinder constituting the clamp portion is formed. The wall thickness of the shaped member 20 can be reduced, and as a result, there is an advantage that the clamp of the clamped member W1 at a low pressure and the diameter expansion amount of the first tubular member 20 are increased.

In the hydraulic clamp device 110, the hydraulic clamp device 10 described above measures the hydraulic pressure of the working liquid chamber 22 and the rotation amount of the working bolt 126 (driving amount of the elastic deformation imparting device) by the pressure sensor 60. The work gripping start point can be detected and the work can be gripped by the same method as the work gripping start point detection method and the work gripping method.

In this embodiment, the gripping force of the member W1 to be clamped is determined based on the pressure of the hydraulic oil in the working liquid chamber 22 at the working gripping start point detected by the work gripping start point detecting method or the rotation amount of the working bolt 126. Can be set.

[Embodiment 5]
Next, the hydraulic clamp device 130 of the fifth embodiment will be described with reference to FIG.

The hydraulic clamp device 130 is a chuck type and has a main body (first member) 132. The main body 132 has a first axial portion 134, a flange portion 136, and a second axial portion 138 having a circular cross-sectional shape on the same axis in order in the axial direction.

At the center of the first axial portion 134, there is a circular cross-sectional shaped bottomed hole 139 opened on the right end surface in the figure and a circumference opened on the inner peripheral surface 139A (first peripheral surface) of the bottomed hole 139. A groove-shaped recess 144 is formed. A tubular member (second member) 140 having an annular cross-sectional shape forming a wall body having a thin wall structure is fitted in the bottomed hole 139.

The tubular member 140 is joined to the first axial portion 134 by brazing or the like, and has a recess 144 on the outer peripheral surface 140A (second peripheral surface) side over the entire circumference of the inner peripheral surface 139A of the bottomed hole 139. The extending cross-sectional shape defines the annular working liquid chamber 142.

The tubular member 140 defines a clamp surface for clamping the round bar-shaped member to be clamped (work) W2 by the inner peripheral surface 140B.

Thus, the tubular member 140 defines the working liquid chamber 142 on the outer peripheral side and the clamp surface (inner peripheral surface 140B) on the inner peripheral side.

The second axial portion 138 includes a recess 146 opened in the central portion of the outer end. An end wall member 148 including an end wall that closes the opening of the recess 146 is joined to the outer end (end) of the second axial portion 138 by brazing or the like. As a result, the end wall member 148 cooperates with the second axial portion 138 to define the pressure vessel 149. In other words, the pressure vessel 149 includes the second shaft-shaped portion 138 and the end wall member 148, and the pressure chamber 150 is defined by the second shaft-shaped portion 138 and the end wall member 148. The pressure chamber 150 communicates with the working liquid chamber 142 by

internal passages

151, 152, 154 and 156 formed in the main body 132.

The hydraulic fluid chamber 142, the pressure chamber 150, and the

internal passages

151, 152, 154, and 156 are filled with hydraulic oil as the hydraulic fluid.

The end wall member 148 has a pedestal portion 148A provided in the central portion and an annular thin-walled portion 148B extending between the pedestal portion 148A and the second axial portion 138. The thin-walled portion 148B has a lower bending rigidity than the base portion 148A, and is easily elastically deformed in the axial direction. By elastically deforming the thin portion 148B to the right in the figure in the axial direction, the volume of the pressure chamber 150 is reduced and the pressure of the hydraulic oil in the pressure chamber 150 is increased.

The pressure increase of the hydraulic oil in the pressure chamber 150 propagates to the hydraulic fluid chamber 22 through the

internal passages

151, 152, 154 and 156, and the pressure rises in the hydraulic oil in the hydraulic fluid chamber 22. By increasing the pressure of the hydraulic oil in the hydraulic fluid chamber 22, the first tubular member 20 is radially inwardly deformed to clamp the member to be clamped W2.

Between the base portion 148A and the second axial portion 138, a plurality of disc springs 162 for urging the end wall member 148 to the left with respect to the second axial portion 138 are provided. The disc spring 162 can be replaced with a compression coil spring or the like.

A linear actuator 158 of an electric type, a fluid pressure type, etc. is arranged outside the end wall member 148. The linear actuator 158 is an elastic deformation imparting device, has a push rod 160 that can be displaced in the axial direction as an axial movement member, and the push rod 160 resists the base portion 148A of the end wall member 148 against the disc spring 162. Press to the right in the figure to elastically deform the thin portion 148B to the right in the figure in the axial direction. The linear actuator 158 is provided with a linear scale 166 that measures the amount of movement of the push rod 160 in the axial direction.

Since the hydraulic clamp device 130 of the present embodiment pressurizes the hydraulic oil of the hydraulic fluid chamber 142 by elastic deformation of the thin-walled portion 148B of the pressure vessel 149, a sliding portion such as a piston is applied to the pressurized portion of the hydraulic oil. Does not exist. That is, since the hydraulic clamp device 130 is pistonless, there is no sealing portion of the sliding portion of the piston, and a problem caused by the sealing portion does not occur. Further, the balance between the sliding resistance of the seal portion and the elastic force of the thin-walled tubular portion does not cause a problem that the thin-walled tubular portion is prevented from being restored to the original state, and the clamped member W2 Unclamping is done smoothly.

Further, since the elastic deformation of the thin-walled portion 148B is urged by the spring force of the disc spring 162 in the direction of releasing the elastic deformation of the thin-walled portion 148B, the elastic deformation of the thin-walled portion 148B in the axial direction is surely and smoothly performed at the time of unclamping. As a result, the depressurization of the hydraulic oil in the hydraulic fluid chamber 142 is reliably and smoothly performed, and the unclamping of the clamped member W2 is reliably and smoothly performed under the expanded diameter deformation of the tubular member 140.

The elastic modulus in the axial direction of the end wall member 148 including the thin-walled portion 148B is higher than the elastic modulus in the radial direction of the portion where the tubular member 140 defines the working liquid chamber 142. Also by this, at the time of unclamping, the elastic deformation of the thin portion 148B in the axial direction is surely and smoothly performed. As a result, the depressurization of the hydraulic oil in the hydraulic fluid chamber 142 is reliably and smoothly performed, and the clamped member W2 is smoothly and reliably unclamped under the expanded diameter deformation of the tubular member 140.

The elastic modulus in the axial direction of the end wall member 148 including the thin-walled portion 148B is higher than the elastic modulus in the radial direction of the portion where the tubular member 140 defines the working liquid chamber 142, so that the tubular member 140 constituting the clamp portion is formed. As a result, the clamp of the member to be clamped W2 at a low pressure and the merit of increasing the diameter reduction amount of the tubular member 140 can be obtained.

Even in the hydraulic clamping device 130, since a part of the pressure vessel 149 is composed of the main body 132, the pressure vessel 149 is simply configured and the communication between the working liquid chamber 142 and the pressure chamber 150 requires an external pipe. It is surely done without doing.

A pressure sensor (pressure measuring device) 60 is attached to the second shaft-shaped portion 138. The pressure sensor 60 applies the pressure of the hydraulic oil in the hydraulic fluid chamber 142 and the pressure chamber 150 by the internal passage 164 formed in the main body 12, and measures the pressure of the hydraulic oil. The pressure of the hydraulic oil in the hydraulic fluid chamber 142 and the pressure of the hydraulic oil in the pressure chamber 150 are the same pressure. The pressure sensor 60 is of a wireless communication type, and transmits measurement value data to a wireless reader 64 arranged in the vicinity of the hydraulic clamp device 130.

In the hydraulic clamping device 130, the above-mentioned is performed based on the measurement of the hydraulic pressure of the working liquid chamber 142 by the pressure sensor 60 and the axial movement amount (driving amount of the elastic deformation imparting device) of the push rod 160 by the linear scale 108. The work gripping start point can be detected and the work can be gripped by the same method as the work gripping start point detection method and the work gripping method in the hydraulic clamping device 10.

In this embodiment, the amount of rotation on the horizontal axis in FIG. 4 is replaced with the amount of movement in the axial direction, and the arithmetic processing unit 76 in FIG. 3 is used to measure the amount of movement in the axial direction of the push rod 160 instead of the measured value of the amount of rotation. Should be entered.

In this embodiment, the clamped member W1 is gripped based on the pressure of the hydraulic oil in the working liquid chamber 142 at the work gripping start point detected by the work gripping start point detection method or the axial movement amount of the push rod 160. You can set the force.

The present invention has been described above with respect to preferred embodiments thereof, but as can be easily understood by those skilled in the art, the present invention is not limited to such embodiments and deviates from the gist of the present invention. It can be changed as appropriate to the extent that it does not.

For example, the structure of the pressure vessel 40 and the elastic deformation imparting device 56 of the mandrel type

hydraulic clamp devices

10, 80, 90 and 110 of the first to fourth embodiments are the chuck type hydraulic clamp device 130 of the fifth embodiment. On the contrary, the structure of the pressure vessel of the chuck type hydraulic clamp device 130 of the fifth embodiment and the elastic deformation imparting device and the like can be applied to the mandrel type

hydraulic clamp devices

10, 80, 90 and 110 of the first to fourth embodiments. Can also be applied to. The

recesses

26 and 144 may be provided in the first cylindrical member 20 and the tubular member 140. In the above embodiment, an example in which hydraulic oil is used as the hydraulic liquid has been described, but water or a gel-like substance can also be used in addition to this.

The elastic modulus in the radial direction of the second tubular member 30, the

tubular portions

84, 94 or the elastic modulus in the axial direction of the end wall 122 and the end wall member 148 is such that the first tubular member 20 defines the working liquid chamber 22. The portion or the tubular member 140 may be equal to the radial elastic modulus of the portion defining the working liquid chamber 142. The pressure sensor 60 is not limited to the wireless communication type, and may be a wired type that transmits a signal via a connector or the like.

Further, not all of the components shown in the above embodiments are indispensable, and they can be appropriately selected as long as they do not deviate from the gist of the present invention.

10: Hydraulic clamp device 12: Main body (first member)
14: First axial portion 14A: Outer peripheral surface (first peripheral surface)
16: Flange portion 18: Second axial portion 18A: Outer peripheral surface 20: First tubular member (second member)
20A: Outer peripheral surface 20B: Inner peripheral surface (second peripheral surface)
22: Working liquid chamber 24: Snap ring 26: Recess 28: O ring 30: Second tubular member 30A: Outer peripheral surface 30B: Inner peripheral surface 32: Pressure chamber 34: Snap ring 36: Recess 38: O ring 40: Pressure Container 42: Internal passage 44: Internal passage 46: Internal passage 48: Steel ball 50: Push screw 52: Diameter reduction member 52A: Opening 52B: Bolt through hole 52C: Screw hole 54: Actuating bolt 56: Elastic deformation imparting device 60: Pressure sensor (pressure detector)
62: Internal passage 64: Wireless reader 70: Electric motor 72: Tool 74: Rotation angle sensor 76: Arithmetic processing device 78: Monitor 80: Hydraulic clamp device 82: Cup-shaped member 84: Cylindrical portion 84A: Outer peripheral surface 86 : End wall 90: Hydraulic clamp device 92: Cup-shaped member 94: Cylindrical portion 94A: Tapered outer peripheral surface 96: End wall 98: Outer fitting member (elastic deformation imparting device)
100: Cylindrical portion 100A: Tapered inner peripheral surface 102: End wall 103: Compression coil spring 104: Linear actuator (elastic deformation imparting device)
106: Push rod (axis direction moving member)
108: Linear scale 110: Hydraulic clamp device 112: Cup-shaped member 114: Cylindrical portion 116: End wall 116A: Base portion 116B: Thin-walled portion 118: Base 120: Cylindrical portion 122: End wall 124: Screw hole 126 : Actuating bolt (elastic deformation imparting device)
128: Compression coil spring 130: Hydraulic clamp device 132: Main body (first member)
134: First axial portion 136: Flange portion 138: Second axial portion 139: Bottomed hole 139A: Inner peripheral surface (first peripheral surface)
140: Cylindrical member (second member)
140A: Outer peripheral surface (second peripheral surface)
140B: Inner peripheral surface 142: Working liquid chamber 144: Recessed 146: Recessed 148: End wall member 148A: Base 148B: Thin-walled portion 149: Pressure vessel 150: Pressure chamber 151: Internal passage 152: Internal passage 154: Internal passage 158 : Linear actuator (elastic deformation imparting device)
160: Push rod (axis direction moving member)
162: Belleville spring 164: Internal passage 166: Linear scale

Claims

A first member having a first peripheral surface forming an outer peripheral surface or an inner peripheral surface, and a second member having a second peripheral surface forming an inner peripheral surface or an outer peripheral surface overlapping the first peripheral surface. A working liquid chamber is defined by recesses provided in at least one of the first peripheral surface and the second peripheral surface in a portion where the first member and the second member overlap each other. A hydraulic clamping device that clamps a member to be clamped by elastically deforming the second member due to the pressure of the working liquid sealed in the working liquid chamber.
A pressure vessel that communicates with the working liquid chamber to define a pressure chamber filled with the working liquid and pressurizes the working liquid in the pressure chamber by elastic deformation.
An elastic deformation applying device that elastically deforms the pressure vessel,
Hydraulic clamp device with.
The hydraulic clamp device according to claim 1, wherein the pressure vessel is integrally provided with the first member and is partially composed of the first member.
The pressure vessel includes a shaft-shaped portion of the first member and a tubular member mounted on the outer periphery of the shaft-shaped portion, and the pressure chamber is defined by the shaft-shaped portion and the tubular member.
The elastic deformation imparting device includes a diameter-reducing member that engages with the outer periphery of the tubular member so as to be able to reduce the diameter and deforms the tubular member by reducing the diameter.
The hydraulic clamp device according to claim 1, wherein the first member includes an internal passage communicating the working liquid chamber and the pressure chamber.
The hydraulic clamping device according to claim 3, wherein the tubular member includes a portion in which the radial elastic modulus is higher than the radial elastic modulus of the portion in which the second member defines the working liquid chamber. ..
The pressure vessel comprises a cup-shaped member that is attached to the end of the first member and has a tubular portion and an end wall that closes the cylindrical portion and the end of the tubular portion opposite to the first member. The pressure vessel is defined by the end portion of the first member and the cup-shaped member.
The elastic deformation imparting device includes a diameter-reducing member that engages with the outer periphery of the tubular portion so as to be able to reduce the diameter and deforms the tubular portion by reducing the diameter.
The hydraulic clamp device according to claim 1, wherein the first member includes an internal passage communicating the working liquid chamber and the pressure chamber.
The pressure vessel is attached to an end portion of the first member, and has a cylindrical portion including a tapered outer peripheral surface at least in a part in the axial direction and an end of the tubular portion opposite to the first member. It is composed of a cup-shaped member having an end wall that closes the portion, and the pressure vessel is defined by the end portion of the first member and the cup-shaped member.
The elastic deformation imparting device is provided with an inner peripheral surface that is slidably fitted to the tapered outer peripheral surface in the axial direction, and the outer diameter of the tubular portion is deformed by displacement in the axial direction with respect to the cup-shaped member. Including fitting members
The hydraulic clamp device according to claim 1, wherein the first member includes an internal passage communicating the working liquid chamber and the pressure chamber.
The hydraulic type according to claim 5 or 6, wherein the tubular portion includes a portion in which the radial elastic modulus is higher than the radial elastic modulus of the portion in which the second member defines the working liquid chamber. Clamping device.
The pressure vessel comprises a cup-shaped member that is attached to the end of the first member and has a tubular portion and an end wall that closes the cylindrical portion and the end of the tubular portion opposite to the first member. The pressure vessel is defined by the end portion of the first member and the cup-shaped member.
The elastic deformation imparting device is provided so as to be displaced in the axial direction with respect to the cup-shaped member, and includes an axially moving member that deforms the end wall in the axial direction due to the displacement in the axial direction.
The hydraulic clamp device according to claim 1, wherein the first member includes an internal passage communicating the working liquid chamber and the pressure chamber.
The first member includes a recess opened at the end.
The pressure vessel includes an end wall member attached to the end portion of the first member, including an end wall that closes the opening of the recess, and the end portion of the first member and the end wall member. Demarcate the pressure vessel,
The elastic deformation imparting device is provided so as to be displaced in the axial direction with respect to the end wall member, and includes an axially moving member that deforms the end wall in the axial direction due to the displacement in the axial direction.
The hydraulic clamp device according to claim 1, wherein the first member includes an internal passage communicating the working liquid chamber and the pressure chamber.
The hydraulic clamp according to claim 8 or 9, wherein the end wall includes a portion in which the elastic modulus in the axial direction is higher than the elastic modulus in the radial direction of the portion where the second member defines the working liquid chamber. Device.
The invention according to any one of claims 8 to 10, further comprising an urging member provided between the first member and the end wall and urging in a direction for restoring axial deformation of the end wall. Hydraulic clamping device.
A first member having a first peripheral surface forming an outer peripheral surface or an inner peripheral surface, and a second member having a second peripheral surface forming an inner peripheral surface or an outer peripheral surface overlapping the first peripheral surface. A working liquid chamber is defined by recesses provided in at least one of the first peripheral surface and the second peripheral surface in a portion where the first member and the second member overlap each other. The pressure of the working liquid sealed in the working liquid chamber causes the second member to be elastically deformed to clamp the member to be clamped, and further communicate with the working liquid chamber to fill the working liquid. In a hydraulic clamping device having a pressure vessel that defines a chamber and pressurizes the working liquid in the pressure chamber by elastic deformation, and an elastic deformation applying device that elastically deforms the pressure vessel, the second member is the clamped member. It is a method of detecting the work gripping start point at the time when the contact with the object is started.
A method for detecting a work gripping start point in a hydraulic clamp device that detects a work gripping start point based on a pressure change of the working liquid with respect to a driving amount of the elastic deformation applying device.
The twelfth aspect of claim 12, wherein the work gripping start point is a time point at which the pressure increase rate of the working liquid with respect to the driving amount of the elastic deformation applying device is changed in a state where the clamped member is attached to the hydraulic clamping device. A method for detecting a work gripping start point in a hydraulic clamp device.
The clamped object is based on the driving amount of the elastic deformation applying device at the work gripping start point detected by the work gripping start point detecting method in the hydraulic clamping device according to claim 12 or 13, or the pressure of the working liquid. A work gripping method using a hydraulic clamp device that sets the gripping force of a member.
A first member having a first peripheral surface forming an outer peripheral surface or an inner peripheral surface, and a second member having a second peripheral surface forming an inner peripheral surface or an outer peripheral surface overlapping the first peripheral surface. A working liquid chamber is defined by recesses provided in at least one of the first peripheral surface and the second peripheral surface in a portion where the first member and the second member overlap each other. The pressure of the working liquid sealed in the working liquid chamber causes the second member to be elastically deformed to clamp the member to be clamped, and further communicate with the working liquid chamber to fill the working liquid. In a hydraulic clamping device having a pressure vessel that defines a chamber and pressurizes the working liquid in the pressure chamber by elastic deformation, and an elastic deformation applying device that elastically deforms the pressure vessel, the second member is the clamped member. It is a device that detects the work gripping start point at the time when the contact with the object is started.
A pressure detection device that detects the pressure of the working liquid, and
A work gripping start point detecting device in a hydraulic clamp device including an arithmetic processing unit that detects the work gripping start point based on a change in the pressure with respect to the driving amount of the elastic deformation applying device.