JP2005246489A - Workpiece holder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To facilitate the rotation angle control of a spindle in a workpiece holder for holding/releasing a workpiece using the rotation of the spindle of a machine tool. <P>SOLUTION: Three parallelogrammic links 130 including levers 132, 134 and links 136 are turnably mounted to a casing 78, and each link 136 is provided with a holding part 176. The rotation of a rotary shaft 90 is converted into the turning motion of the levers 132, 134 by a motion converter 92 comprising an external screw member 180, an internal screw member 182, a projecting part 200 and a groove 202, and the link 136 is moved to hold the workpiece 10 by the holding part 176. The external screw member 180 has a small lead angle, and even if there is an error in the rotation stop position of a tool spindle 22, the stop position error of the holding part 176 is small, and control accuracy of the rotation angle of the tool spindle 22 may be low. Rotation angle control becomes much easier by transmitting the rotation of the internal screw member 182 to the external screw member 180 through a torque limiter 88 to prevent transmission of excessive torque. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a work holder, and more particularly to a work holder that holds and releases a work piece by utilizing rotation of a spindle of a processing machine.

  This type of work holder is already known as described in Patent Document 1 and Patent Document 2, for example. The work holder described in Patent Document 1 is configured to clamp and release a workpiece by using a cam to bring a pair of clamping claws closer to and away from each other. The work holder is supported by a housing so as to be relatively rotatable and rotated by a main shaft, and an operation shaft which is relatively non-rotatable by the housing and is relatively movable in the axial direction and is held concentrically with the rotating shaft. A cylindrical driving cam fixed to the rotating shaft, a cylindrical driven cam provided on the operating shaft so as to face the driving cam, and a housing that are three-dimensionally intersecting at right angles with the rotating axis of the rotating shaft. And a pair of sandwiching claws provided so as to be able to approach and separate from each other, and a pair of links connecting the operating shaft and the pair of sandwiching claws. Corrugated cam surfaces having crests and troughs at a rotation angle interval of 90 degrees are formed on end surfaces of the driving cam and the driven cam, which are opposed to each other. And the driven cam are biased in the direction in which the cam surfaces mesh with each other. If the rotating shaft is rotated 90 degrees by the main shaft from the state where the crests and troughs of each cam surface of the driving cam and the driven cam are engaged with each other, the crests of each cam surface come into contact with each other, and the operating shaft is It is moved in a direction away from the rotation shaft, the pair of links are rotated, the pair of clamping claws are separated from each other, and the workpiece is released. If the rotating shaft is further rotated 90 degrees in the same direction or in the opposite direction by the main shaft, the peak portion and the valley portion are engaged with each other, and the pair of holding claws are brought close to each other to hold the workpiece.

The work holder described in Patent Document 2 is configured to use a rack and a pinion to bring a pair of gripping members closer to and away from each other and grip and release the workpiece. This work holder is supported by a housing so as to be relatively rotatable and rotated by a main shaft, a pinion concentrically provided on the rotation shaft and provided with a non-rotatable and non-relatively movable axially, and a housing. A pair of racks that are held so as to be relatively movable in a direction perpendicularly intersecting the rotation axis of the rotation axis and meshed with the pinions, and a gripping member held in each of the racks are provided. The pair of racks are provided in parallel to each other, and if the rotation shaft is rotated by the main shaft, the pinion is rotated, the pair of racks are moved in opposite directions, and the pair of gripping members are separated from each other, Release the workpiece. If the rotating shaft is rotated in the opposite direction, the pair of racks are moved in the opposite direction to the above, and the pair of gripping members are brought close to each other to grip the workpiece.
JP-A-9-29574 JP 2003-181736 A

However, in the work holder described in Patent Document 1, the rotation angle of the rotating shaft when changing the distance between the pair of clamping claws from the minimum to the maximum is 90 degrees, and the workpieces having different dimensions are clamped. Therefore, it is necessary to increase the accuracy of the rotation stop position control of the rotation shaft, since it is necessary to stop the rotation of the rotation shaft at a plurality of rotation positions in the rotation angle range of 90 degrees. If the rotation angle is insufficient, the clamping may be insufficient and the workpiece may be dropped. If the rotation angle is excessive, the force applied by the clamping claws to the workpiece may be excessive, which may damage the workpiece. Because.
Also, in the work holder described in Patent Document 2, since the length of the pair of racks is naturally limited due to the structure, the pinion and the rotation shaft when the distance between the pair of gripping members is changed from the minimum to the maximum. The rotational angle is limited to be relatively small, and it is necessary to increase the accuracy of the rotational stop position control of the rotational shaft.
In view of the above circumstances, the present invention provides a work holder for holding and releasing a workpiece by using the rotation of the spindle of the processing machine in order to attach and detach the workpiece to and from the workpiece holding part of the processing machine. An object of the present invention is to facilitate rotation angle control.

In order to solve the above problems, a work holder according to the present invention includes: (A) a rotary shaft that is rotatably and detachably attached to a main shaft of a processing machine; A body member that is engaged with a non-rotating part of the processing machine; and (C) a plurality of holding members that are provided so as to be relatively movable with respect to the body member and hold the workpiece together. D) a motion conversion device that is provided between the rotating shaft, the main body member, and the holding member, and converts a relative rotation of the rotating shaft with respect to the main body member into a motion of holding and releasing the workpiece of the holding member, A motion conversion device, (a) a first screw member that rotates together with the rotating shaft, and (b) is held by the main body member so as not to be relatively rotatable and relatively movable in the axial direction, and is screwed to the first screw member. And a second screw member Flip is characterized in that the relative movement in the axial direction relative to the body member of the member is to convert the motion of said plurality of retaining members.
The first screw member and the second screw member may be arranged coaxially with the rotation axis, or may be arranged on different axes. For example, the first and second screw members may be located in one plane including the axis of the rotation axis and disposed on an axis parallel to the axis of the rotation axis. In this case, for example, a rotation transmission device that transmits the rotation of the rotation shaft to the first screw member is provided between the first screw member and the rotation shaft so that the first screw member rotates together with the rotation shaft. .

In the work holder according to the present invention, the rotation shaft is rotated and the first screw member is rotated, whereby the second screw member screwed with the first screw member is moved in the axial direction, and a plurality of screw members are moved. The holding members are moved all at once to hold and release the workpiece. The first screw member is rotated in opposite directions when holding and releasing the workpiece, and the plurality of holding members are moved simultaneously in the workpiece holding direction or the releasing direction.
According to this work holder, it is possible to easily control the rotation angle of the rotation shaft, that is, the rotation angle of the main shaft of the processing machine. If the lead angle of the screw of the first and second screw members is reduced, the axial movement distance of the second screw member with respect to the same rotation angle of the first screw member can be shortened, and the actual rotation angle of the rotation shaft However, even if it is slightly larger than the angle required for holding the workpiece, the increase in the movement distance in the axial direction of the second screw member can be small. Therefore, even if the rotation angle of the rotating shaft for holding and releasing the workpiece is slightly larger than the angle suitable for holding, the workpiece is securely held without being damaged by applying excessive holding force. Therefore, the accuracy of the rotation angle control of the rotation shaft can be lowered, and the control becomes easy.
In addition, this work holder is suitable for holding a plurality of types of workpieces having different sizes of held parts. If the rotation angle of the rotating shaft and the first screw member is increased, the moving distance of the holding member increases. Therefore, the rotation angle range of the rotating shaft for holding and releasing them according to the dimensions of multiple types of held parts. By setting a plurality of types (angle range between the holding angle and the release angle), it is easy to cope with the difference in the size of the held portion.

Aspects of the Invention

  In the following, the invention that is claimed to be claimable in the present application (hereinafter referred to as “claimable invention”. The claimable invention is at least the “present invention” to the invention described in the claims. Some aspects of the present invention, including subordinate concept inventions of the present invention, superordinate concepts of the present invention, or inventions of different concepts) will be illustrated and described. As with the claims, each aspect is divided into sections, each section is numbered, and is described in a form that cites the numbers of other sections as necessary. This is for the purpose of facilitating the understanding of the claimable invention, and is not intended to limit the combinations of the constituent elements constituting the claimable invention to those described in the following sections. In other words, the claimable invention should be construed in consideration of the description accompanying each section, the description of the embodiments, etc., and as long as the interpretation is followed, another aspect is added to the form of each section. In addition, an aspect in which constituent elements are deleted from the aspect of each item can be an aspect of the claimable invention.

  In each of the following paragraphs, (1) corresponds to claim 1, (2) corresponds to claim 2, (3) claim 3, (5) claims 4 and ( Item 6) corresponds to item 5 respectively.

(1) a rotating shaft that is rotatably and detachably attached to the main shaft of the processing machine;
A main body member that holds the rotation shaft so as to be relatively rotatable and is engaged with a non-rotating portion of the processing machine;
A plurality of holding members provided so as to be relatively movable with respect to the main body member and holding the workpiece in cooperation with each other;
A motion conversion device that is provided between the rotating shaft, the main body member, and the holding member, and converts relative rotation of the rotating shaft with respect to the main body member into a motion of holding and releasing the workpiece of the holding member. A work holder that holds the workpiece for attaching to and detaching from the work holding portion of the processing machine,
The motion conversion device is
A first screw member that rotates with the rotating shaft;
A second screw member that is held by the main body member so as not to rotate relative to the main body and that can move relative to the axial direction, and is screwed with the first screw member, the second screw member moving relative to the main body member in the axial direction; A work holder that converts the movement into the movement of the plurality of holding members.
(2) The first screw member is held by the main body member so as to be relatively rotatable, and torque less than a set value is transmitted between the first screw member and the rotary shaft, but exceeds the set value. The work holder as set forth in (1), wherein a torque limiter that does not transmit is provided.
When holding the workpiece, if the plurality of holding members come into contact with the workpiece, the rotating shaft is further rotated from the held state, and the first screw member is rotated, the force by which the holding member holds the workpiece is increased. There is a concern that at least one of the workpiece and the holding member may be damaged. On the other hand, if the torque limiter is provided, even if the rotating shaft is further rotated from the state where the plurality of holding members hold the workpiece, the rotational torque exceeding the set value is not transmitted to the first screw member. Therefore, for example, even if there is an error in the rotation angle control of the rotation shaft, the workpiece can be held without being damaged. In addition, even if the holding member is worn, an insufficient approach / separation distance between the two holding members is automatically avoided, and the workpiece is reliably held.
Furthermore, as described above, the rotation angle control of the rotation shaft that is facilitated by including the first and second screw members in the motion conversion device is further facilitated. This is because even if the rotation angle of the rotation shaft is large, the torque limiter prevents transmission of torque exceeding the set value to the first screw member, thereby avoiding damage to the workpiece.
(3) The torque limiter is
A first limiter member that always rotates with the first screw member;
A second limiter member that always rotates with the rotating shaft;
One of the first limiter member and the second limiter member is provided with a plurality of first engaging portions provided on a circumference around one rotation axis, and the first limiter member and the second limiter member. A second engagement portion that is held on the other side and elastically engages with the first engagement portion, and the relative rotational torque between the first limiter member and the second limiter member is equal to or less than the set value. The work holder according to item (2), wherein the second engaging portion does not come off from the first engaging portion and comes off when exceeding the set value.
The first screw member and the first limiter member, and the second screw member and the second limiter member may be arranged coaxially or on different axes.
The first limiter member and the second limiter member rotate relative to each other if the relative rotational torque exceeds the set value. However, since the plurality of first engaging portions are provided, the first and second limiter members are Regardless of the phase of the two limiter members, the first engagement portion and the second engagement portion are engaged with each other, and the torque limiter transmits torque below the set value but does not transmit torque exceeding the set value. Easy to return automatically. Therefore, for example, when the workpiece is released after holding the workpiece, the operator does not engage the first and second engaging portions with each other so that the rotation of the rotating shaft is transmitted to the first screw member. Often done.
(4) The work holder according to (3), wherein the first engagement portion and the second engagement portion face each other in the axial direction.
The first limiter member and the second limiter member are fitted so that one of the first limiter member and the second limiter member can be relatively rotated inside or outside of the other. It is also possible to make them face each other. However, if the first engaging portion and the second engaging portion are opposed to each other in the axial direction, the torque limiter can be configured compactly.
(5) The work holder according to (3) or (4), wherein the first engaging portion is configured by a part of a corrugated uneven portion formed continuously along the circumference of the circle.
The portion of the corrugated uneven portion that engages with the second engaging portion when the rotating shaft stops constitutes the first engaging portion, and the first engaging portion and the second engaging when the rotating shaft stops rotating Regardless of the relative phase with respect to the part, the first and second engaging parts are engaged, and a state of functioning as a torque limiter is obtained.
(6) The second engagement portion is
An accommodating recess provided in the other of the first limiter member and the second limiter member;
A ball that is held so that at least a part thereof protrudes from the front end opening of the housing recess;
The work holder according to any one of (3) to (5), further comprising an elastic member disposed in the housing recess and biasing the ball in a protruding direction.
In the state where the relative rotational torque is not more than the set value, the ball is kept engaged with one of the first and second limiter members and rotates both limiter members integrally. If the relative rotational torque exceeds the set value, the ball is retracted into the receiving recess against the urging force of the elastic member, and the relative rotation of the first and second limiter members is allowed and the torque transmission is interrupted.
The set value of the relative rotational torque is set to a magnitude corresponding to the elastic force of the elastic member. When a plurality of second engaging portions are provided, the number is selected such that the sum of the relative rotational torques according to the elastic forces of the plurality of elastic members becomes a set value.
(7) The work holder according to any one of (3) to (6), wherein the first limiter member is provided coaxially with the first screw member.
The first limiter member may be provided on a different axis from the first screw member. In this case, for example, a rotation transmission device is provided between the first limiter member and the first screw member so that the rotation of the first limiter member is transmitted to the first screw member and rotates together. According to the work holder of this section, for example, the work holder can be configured compactly with respect to the direction intersecting the rotation axis of the rotation shaft.

(8) The work holder according to any one of (1) to (7), wherein the first screw member is disposed coaxially with the rotating shaft.
According to the work holder of this section, for example, the work holder can be configured compactly with respect to the direction intersecting the rotation axis of the rotation shaft.
(9) Item (1) to Item (8), wherein the first screw member has an external thread formed on the outer peripheral surface, and the second screw member has an internal thread formed on the inner peripheral surface. The work holder according to any one of the above.
(10) Item (1) to Item (8), wherein the first screw member has an internal thread formed on the inner peripheral surface, and the second screw member has an external thread formed on the outer peripheral surface. The work holder according to any one of the above.

(11) A parallelogram link including the main body member, a pair of levers rotatably held by the main body member, and a connecting member that connects the free ends of the pair of levers has an axis of symmetry. A plurality of parallelogram links formed on the body member in axial symmetry with respect to the body member, and the motion conversion device converts relative rotation of the rotating shaft with respect to the body member into motion of the parallelogram links The work holder according to any one of (1) to (10), wherein a holding portion is provided in each of the plurality of connecting members, and the connecting members function as the holding member.
There may be two parallelogram links, or three or more. Even if there are two, for example, if the holding part has a holding surface that comes into surface contact with the held part of the workpiece, the workpiece can be stably held.
The motion conversion device converts the rotation of the rotary shaft into an axial movement by the first and second screw members, and converts the axial movement into a rotational movement of a pair of levers, and a plurality of parallelogram links The pair of levers are simultaneously rotated while maintaining a state of axial symmetry with respect to the symmetry axis, and the plurality of holding members approach and separate from each other to hold and release the workpiece.
By setting at least one of the length of the lever, that is, the distance between the rotation axis of the lever relative to the main body member and the rotation axis of the connecting member, and the rotation angle of the lever, the maximum approach / separation distance of the plurality of holding portions is set. Can be changed. In particular, the larger the ratio of the lever ratio, that is, the length of the lever and the length of the lever rotation axis and the portion on which the driving force obtained by the motion conversion device acts, the greater the holding member can be moved. Therefore, the lever has a length capable of giving the holding member a moving amount capable of holding a plurality of types of workpieces having different sizes, and the lever ratio is set as large as possible so that the workpiece can be covered. By setting the rotation angle of the lever according to the size of the holding portion, the holding member is moved by a distance according to the size of the held portion, and multiple types of workpieces having different sizes can be easily held. be able to.
For example, when a plurality of holding members are moved toward and away from each other by a linear motion to hold and release a workpiece, a guide device for guiding the movement is necessary, and the workpiece holder has the largest workpiece to be held. A guide device capable of guiding the movement of the plurality of holding members when holding the piece is provided, and the size becomes large. On the other hand, if the lever is used, when the held part holds a large workpiece, the rotation angle of the lever is increased and the holding part is greatly separated from the axis of symmetry, but when the workpiece is not held, , The lever can be turned to the main body member side and kept closed, and if the held part is small, the turning angle is small and does not always require a large space, and the work holder becomes large Thus, a work holder that can hold a plurality of types of workpieces having different sizes can be obtained.
In addition, since the holding part is provided on the connecting member of the parallelogram link, even if the rotation angle of the lever is different, the posture of the holding part with respect to the main body member does not change, and the sizes of the held parts are different. Can be held in the same posture.
(12) The work holder according to item (13), wherein the parallelogram link group includes three parallelogram links.
The work holder in this section includes three holding portions, and can stably hold the workpiece at three locations. For example, a workpiece having a circular cross-sectional shape of the gripped surface can be centered and held, which is suitable for holding the workpiece.
(13) A plane including two relative rotation axes of the pair of levers with respect to the main body member and a plane including two relative rotation axes of the free end portions of the pair of levers with respect to the connecting member. The work holder according to (11) or (12), wherein both are parallel to the axis of symmetry and parallel to each other.
In the work holder of this section, when the parallelogram link group is moved by the motion conversion device, the connecting member is moved while maintaining a posture parallel to the symmetry axis. Therefore, for example, if the held part is a workpiece parallel to the axis of symmetry, the holding parts provided in each of the connecting members can always be engaged with the held part in the same state even if the sizes are different.

(14) The workpiece includes a supported surface and two engaged surfaces extending in opposite directions and extending in a direction intersecting the supported surface, and the two holding members are provided. And at least one of the two holding members includes a support member having a support surface that supports the supported surface and an engagement member that engages with the engaged surface, and the other includes at least the engaged member. Including an engaging member that engages with a mating surface, wherein each of the motion conversion devices includes two levers that are respectively held by the body member and hold each of the two holding members, and rotate the levers. The work holder according to any one of (1) to (10), wherein the two holding members are moved in a direction in which the two engaging members approach and separate from each other.
In the work holder of this section, similarly to the work holder described in the section (11), it is possible to hold a plurality of types of workpieces having different sizes of held parts while preventing the work holder from becoming large. Can do.
The engaging member and the supporting member may be directly fixed to each other, or may be indirectly fixed via another member such as a lever. Further, they may be integrated with each other.
In the workpiece holder of this section, the two levers are rotated, and the two engaging members are engaged with the engaged surfaces to hold the workpiece. Further, when the two engaging members engage with the workpiece, the supporting member can come into contact with the supported surface of the workpiece on the supporting surface, and the workpiece can be supported. If the two levers are rotated in opposite directions, the two engaging members are separated from the engaged surface to release the workpiece, and the support member is separated from the supported surface to release the workpiece. To do.
By setting at least one of the length of the lever, that is, the distance between the lever rotation axis and the engagement member, and the rotation angle of the lever, the maximum approach / separation distance between the two engagement members can be changed. Therefore, the lever has a length capable of holding a plurality of types of workpieces having different sizes of the held portion, and the rotation angle of the lever is set according to the distance between the two engaged surfaces. Thus, a plurality of types of workpieces can be held. When holding a workpiece having a large distance between the two engaged surfaces, the lever is rotated so that the engaging member is largely separated from the main body member. Can be rotated and closed to the main body member side, and a work holder capable of holding a plurality of types of workpieces having different sizes can be obtained while avoiding the work holder from becoming large.
Moreover, since this work holder is provided with the support surface and can support a workpiece by a surface, it can hold | maintain a workpiece stably. For example, when the supported surface is downward and the support surface is provided upward, the support member can support the workpiece from below, and when the workpiece is heavy, the engagement member is particularly heavy and has two centers of gravity. Even when a rotational torque around the straight line that deviates from the straight line connecting the two engaged parts held by the above-mentioned line is generated, it can be stably held. When the supported surface is an upward surface, the support surface is a downward surface, but rotation around the straight line connecting the two engaged portions of the workpiece is still prevented by the support surface, and the work holder is heavy. Even a workpiece can be stably held. The same applies to the case where the supported surface and the supporting surface are vertical or inclined. In order to hold the workpiece stably, it is desirable to provide two support members. However, the workpiece holder is provided in the processing machine and is used to attach and detach the workpiece to the workpiece holder. It does not have to be held with high accuracy and accuracy, and there may be only one support member. Even if there is only one support surface, the workpiece can be supported widely by the surface, and sometimes only one is sufficient.
(15) The work holder according to (14), wherein the support surfaces of the support members are parallel to the axis of the rotation shaft.
According to this section, for example, the work holder can be made compact in the direction intersecting the rotation axis.
(16) The work holder according to (15), wherein a support surface of the support member is positioned on one plane, and the main body member, the support member, and the motion conversion device are arranged on one side of the plane.
If a main body member or the like is arranged on one side of the support surface, a space on the opposite side of the support surface from the main body member or the like is vacant, for example, a work piece having various shapes, dimensions, etc. may interfere with the main body member or the like And can be supported on the support surface.
In the work holder of this section, when support members are provided corresponding to the two holding members, the support surfaces of the support members are respectively positioned on one plane. It is not essential that the two support surfaces are located on the same plane. For example, the support surfaces may be provided so as to be located in two different planes parallel to each other. The workpiece holder having the support surface is suitable for holding a workpiece having two supported surfaces, each of which has a stepped portion and is positioned in two different planes parallel to each other.

(17) The plurality of holding members are arranged symmetrically with respect to one symmetry axis, and the motion conversion device is
A cam having a cam surface that is held by the body member so as to be movable on the one axis of symmetry and is inclined with respect to the axis of symmetry;
Biasing means for pressing the cam followers of the plurality of holding members against the cam surface of the cam;
The work holder according to any one of (1) to (10), including a rotation / linear motion conversion mechanism that converts relative rotation of the rotation shaft with respect to the main body member into movement of the cam.
When the cam is moved, the cam follower is moved in a direction orthogonal to the symmetry axis against the urging force of the urging means, and the plurality of holding members are separated (or approached) all at once. If the cam is moved in the reverse direction, the cam follower is moved by the urging force of the urging means, and the plurality of holding members are moved toward (or separated from) each other. The workpiece is held / released by the approach / separation of the plurality of holding members.
(18) The cam includes two cam followers that are provided at two positions separated from the cam surface in the axial direction, and each of the plurality of holding members is engaged with the cam surfaces at the two positions. Work holder according to item.

(19) The work holder according to any one of (1) to (18);
A tool spindle as the spindle that rotates with a tool holding device that removably holds a processing tool at the tip; and
A workpiece attachment portion to which a workpiece to be machined by the machining tool is attached;
The tool spindle and the work mounting part are moved relative to each other so that the work holder held by the tool holding device of the tool spindle holds the work piece and is attached to the work mounting part, and instead of the work holder. And a relative movement device that causes the work tool held by the tool holding device to work the workpiece attached to the work attachment portion.
Using the tool spindle, the tool holding device, and the relative movement device, the work holder can be attached to the work attachment portion. As compared with the case where the workpiece holder is moved by a dedicated relative movement device and the workpiece is attached to the workpiece attachment portion, the processing machine can be configured easily and inexpensively. Further, if the work holder is accommodated in the processing tool accommodating device, a dedicated accommodating space is not required.
An automatic tool changer provided separately from the relative movement device performs an automatic change function for exchanging the work holder held in the tool holding device of the tool spindle with the machining tool or exchanging the work tool with the work holder. It is also possible to make it. However, it is also possible for the relative movement device to perform at least part of the automatic exchange function, which can further simplify the configuration.

  In the following, several embodiments of the claimable invention will be described in detail with reference to the drawings.

<First Example>
1 and 2 schematically illustrate a processing machine which is an embodiment of the claimed invention. This processing machine is a machining center, and various workpieces including the workpiece 10 are processed. The workpiece 10 is provided with an opening 14 which opens on an end surface 12 which is one surface of the workpiece 10 and which is an outer surface perpendicular to the axis. In the present embodiment, the opening 14 has a circular cross-sectional shape, and the inner side surface 16 is a cylindrical surface and is orthogonal to the end surface 12. The workpiece 10 is, for example, a housing of an automobile transmission.

  The processing machine includes a work holder 20, a tool spindle 22 as a spindle, a workpiece holding jig 24, a tool spindle moving device 26 as a relative moving device, a tool storage device 27, and an automatic tool changing device 28. This processing machine is a so-called vertical machine in which the tool spindle 22 is provided so as to be rotatable about a vertical axis, and the tool spindle moving device 26 has two directions orthogonal to each other in the horizontal plane (one in the X axis direction and the other in the other direction). Is moved in the Y-axis direction) and in the vertical direction (Z-axis direction). Therefore, the tool spindle moving device 26 includes an X-axis moving device 30, a Y-axis moving device 32, and a Z-axis moving device 34, as schematically shown in FIGS. The X-axis moving member 36 of the X-axis moving device 30 is moved in the X-axis direction by an X-axis driving device that uses a servomotor with an encoder (not shown) as a drive source, and the Y-axis moving member 38 of the Y-axis moving device 32. Is moved in the Y-axis direction on the X-axis moving member 36 by a Y-axis drive device using a servomotor with an encoder as a drive source. The Z-axis moving member 40 of the Z-axis moving device 34 is moved in the Z-axis direction on the Y-axis moving member 38 by a Z-axis driving device using a servomotor with an encoder as a drive source. A spindle housing 50 is provided on the Z-axis moving member 40 and constitutes a non-rotating portion of the processing machine. The tool spindle 22 is held so as to be rotatable about a vertical axis. The tool spindle 22 is a servo motor with an encoder. It is rotated by a spindle rotation driving device 52 as a driving source. The servo motor is an electric motor capable of accurately controlling the rotation angle, and a step motor may be used instead of the servo motor.

  In this embodiment, the work holding jig 24 is fixedly provided at a position adjacent to the X-axis moving device 30 in the X-axis direction, constitutes a work mounting portion, and holds and releases the workpiece 10. To do. In addition, as shown in FIG. 2, a tool storage device 27 is provided at a position adjacent to the tool spindle moving device 26 in the Y-axis direction. In the tool storage device 27, a plurality of types of processing tools 62 and the work holder 20 are stored. The tool storage device is a tool storage device in which the processing tool 62 is mainly stored. An automatic tool changer 28 is mounted on the Z-axis moving member 40 together with the tool spindle 22. In the present embodiment, the automatic tool changer 28 is provided so as to be rotatable about a vertical axis, and a holding arm 68 as a holding member provided with holding parts 66 at both ends, and an arm rotation driving device for rotating the holding arm 68. (Not shown) and an arm moving device (not shown) that moves the holding arm 68 in a direction parallel to the rotation axis, and the like. By rotating and moving the holding arm 68, the tool spindle 22 and the tool storage device 27 The processing tool 62 and the work holder 20 are delivered between the two. In the present processing machine, the workpiece 10 is carried in and out by a robot (not shown). The work holder 20 is attached to the tool spindle 22 and transfers the workpiece 10 to and from the robot and the workpiece holding jig 24.

The work holder 20 will be described.
In this embodiment, as shown in FIG. 3, the work holder 20 includes a casing 78 as a main body member, a relative rotation prevention device or engagement device 80, a parallelogram link group 82, and a parallelogram link as described later. A plurality of, for example, three holding members constituted by links, a drive device 86 and a torque limiter 88 are included. The drive device 86 includes a rotation shaft 90 and a motion conversion device 92. The casing 78 holds the rotating shaft 90 through a plurality of bearings 94 so as to be relatively rotatable about a vertical axis thereof and not to be relatively movable in the axial direction. The rotating shaft 90 is provided with a shank portion 96 whose diameter decreases linearly toward the projecting end of the projecting portion from the casing 78. The shank portion 96 has a tapered shape provided at the tip of the tool spindle 22. A pull stud (not shown) that is fitted in the fitting hole 97 and protrudes from the shank portion 96 is pulled by the draw bar, and drawn into the tool spindle 22 and held. In addition, a plurality of engagement protrusions 98 provided at the tip of the tool spindle 22 are respectively fitted into a plurality of engagement recesses 100 provided at the base end portion of the shank portion 96 and are engaged with each other. The rotation shaft 90 is prevented from rotating with respect to the tool spindle 22, and the rotation shaft 90 is rotatably attached to the tool spindle 22 together. The engagement protrusion 98 and the engagement recess 100 each constitute an engagement portion or a rotation transmission portion, and both constitute a rotation transmission device. The rotating shaft 90 can be detached from the tool spindle 22 by moving the rotating shaft 90 in a direction of coming out of the tool spindle 22 in a state where the holding of the pull stud by the draw bar is released.

  The casing 78 is engaged with the main shaft housing 50 by the engaging device 80 and is prevented from relative rotation. The engaging device 80 includes a casing 106 provided integrally with the casing 78, an engaging member 108 movably fitted in the casing 106 in a direction parallel to the axis of the rotating shaft 90, and the engaging member 108. And a compression coil spring 110 as an elastic member, which is a kind of a biasing device that biases the casing in the rearward direction, that is, in the direction in which the shank portion 90 of the casing 78 projects from the same side. The compression coil spring 110 is a kind of spring, and the limit of movement of the engaging member 108 by the bias of the spring 110 is that the flange portion 112 radially outward as an engaging portion provided in the engaging member 108 is used. It is defined by engaging a shoulder surface 114 as a stopper provided in the casing 100. In addition, the engaging member 108 is inserted into a pair of notches 118 that are provided in the casing 106 and constitute an engaging portion, by engaging a pin 116 as an engaging member penetrating in the diametrical direction. The rotation with respect to the casing 106 is prevented.

  The pin 116 extends from the casing 106 toward the rotating shaft 90, and when the work holder 20 is detached from the tool main shaft 22, the engaging member 108 is at a movement limit position due to the bias of the spring 110. The protruding end portion of 116 is fitted into a groove 120 provided at the proximal end portion of the shank portion 96, and the rotation of the rotating shaft 90 relative to the casing 78 is prevented. When the rotary shaft 90 is fitted to the tool spindle 22, first, the engagement protrusion 122 provided on the engagement member 108 is fitted into the engagement recess 124 provided on the spindle housing 50, and the engagement member 108. Movement is stopped. When the rotary shaft 90 is further fitted to the tool spindle 22 from this state, the casing 78, the rotary shaft 90, and the casing 106 move relative to the engaging member 108 in the axial direction, and the tool spindle 22 and the spindle housing 50 are moved. And the pin 116 is pulled out of the groove 120. The engaging protrusion 98 is fitted into the engaging recess 100 before the pin 116 comes out of the groove 120. By the extraction of the pin 116, relative rotation between the casing 78 and the rotating shaft 90 is allowed. The casing 78 holds the rotating shaft 90 so as to be relatively rotatable, and the casing 78 is engaged with the main shaft housing 50 so as not to be relatively rotatable. The rotating shaft 90 can be rotated together with the tool spindle 22. When the work holder 20 is removed from the tool spindle 22, the pins 116 are fitted into the grooves 120 before the engaging protrusions 98 come out of the engaging recesses 100, and the phase between the rotating shaft 90 and the casing 78 is determined.

  The work holder 20 is attached to the tool spindle 22 similarly to the processing tool 62. The processing tool 62 includes a tapered shank portion, an engagement recess that is fitted to the engagement protrusion 98 of the tool spindle 22, and the tool spindle 22 is fitted to the tool spindle 22 so as not to rotate relative thereto. It is drawn into and held inside. In this embodiment, the engagement protrusion 98, the tapered fitting hole 97 into which the shank portion 96 is fitted, the draw bar, and the like constitute a tool holding device.

  The parallelogram link group 82 includes a plurality of, for example, three parallelogram links 130 as shown in FIG. These three parallelogram links 130 are composed of a casing 78, a pair of levers 132 and 134, and one link 136 as a connecting member, as shown in FIG. As shown, the casing 78 is provided at equiangular intervals around the rotation axis of the rotation shaft 90. The three parallelogram links 130 are configured on the casing 78 so that the rotational axis of the rotational shaft 90 is a symmetric axis, and is symmetrical about the symmetric axis.

  As shown in FIGS. 3 and 4, the casing 78 opens to the tip end surface (the end surface opposite to the side from which the shank portion 96 of the rotating shaft 90 is projected) and the outer peripheral surface. A plurality of, for example, three, for example, three grooves 138 that are located in one plane including the rotation axis and extend in the axial direction are provided at equal angular intervals. One end of each of the levers 132 and 134 is fitted in each of the grooves 138 and can be rotated around an axis that is three-dimensionally intersected with the casing 78 by a shaft 140 and 142 at a right angle to the rotation axis of the rotation shaft 90. Is attached. The relative rotation axes of the levers 132 and 134 with respect to the casing 78 are parallel to each other. In this embodiment, the two relative rotation axes are included in one plane parallel to the rotation axis of the rotation shaft 90. Yes.

  The free end portion of the lever 132 is divided into two forks, and a yoke portion 144 is provided. As shown in FIG. 5, the other end portion of the link 136 is fitted, and the shaft 148 causes the lever 132 to move relative to the casing 78. It is connected so as to be rotatable around an axis parallel to the rotation axis. The free end portion of the lever 134 is thinned and fitted into a yoke portion 150 provided at one end portion of the link 136, and is rotated around an axis parallel to the relative rotation axis of the lever 134 with respect to the casing 78 by the shaft 152. It is linked movably. The relative rotation axes of the free ends of the levers 132 and 134 with respect to the links 138 are parallel to each other, and the two relative rotation axes are included in one plane parallel to the rotation axis of the rotation shaft 90. ing. A plane including two relative rotation axes for the casing 78 of each of the pair of levers 132 and 134, and a plane including two relative rotation axes for each casing 78 of the free ends of the pair of levers 132 and 134 Are parallel to the axis of the rotation axis 90, both of which are symmetrical axes, and parallel to each other. Therefore, the link 136 is moved in the radial direction and the axial direction of the work holder 20 while maintaining the posture in which the longitudinal direction is parallel to the rotation axis of the rotation shaft 90.

  As shown in FIG. 3, the link 136 is provided with a groove 170 as an engaging portion that opens on an outer surface thereof, that is, a surface opposite to the casing 78 side and penetrates in a direction parallel to the rotation axis. ing. In the present embodiment, the groove 170 is an annular groove centered on the rotation axis of the rotation shaft 90, and among the openings 14 of the plurality of types of workpieces 10 scheduled to be held by the work holder 20, It forms part of an annular groove having a curvature slightly larger than the curvature of the opening 14 having the smallest diameter. By providing the groove 170, the link 136 forms the bottom surface of the groove 170, is parallel to the rotation axis of the rotation shaft 90, and forms the partial cylindrical surface engaging surface 172 and the side surface of the groove 170. A planar support surface 174 that is perpendicular to the rotation axis of the rotation shaft 90 and orthogonal to the engagement surface 172 on the front end side (lower side) of the casing 78 is provided. When the levers 132 and 134 are rotated, the engagement surface 172 and the support surface 174 are moved together with the link 136 without changing the posture with respect to the rotation shaft 90. The portion of the link 136 provided with the groove 170 constitutes a holding portion 176, and in this embodiment, the link 136 functions as a holding member that holds the workpiece 10.

  As shown in FIG. 3, the lever 134 is provided with a plunger device 160. When the levers 132 and 134 and the link 136 are located at a storage position to be described later, the lever 134 is attached in the opening direction (holding position side). It has been made to force. The plunger device 160 includes a contact member 164 provided in the casing 162 so as to be movable in the axial direction, and biasing the contact member 164 in a direction in which the contact member 164 protrudes from the casing 162 toward the bottom surface of the groove 138 of the casing 78. There are provided urging means (for example, a compression coil spring as a spring which is a kind of elastic member) and a movement limit defining portion (not shown) for defining a movement limit of the contact member 164 by the urging means.

  In this embodiment, the motion conversion device 92 includes a male screw member 180 as a first screw member and a female screw member 182 as a second screw member, as shown in FIG. The male screw member 180 has a male screw portion 184 formed on the outer peripheral surface, and the lead angle of the male screw portion 184 is reduced. The male screw member 180 is fitted in a portion rotatably supported by the bearing 94 of the rotating shaft 90 so as to be relatively rotatable about the axis of the rotating shaft 90 and not to be relatively movable in the axial direction. The male screw member 180 is held by the casing 78 so as to be relatively rotatable, and is disposed coaxially with the rotating shaft 90. The female screw member 182 has a female screw portion 186 formed on the inner peripheral surface, and is screwed into the male screw member 180. As shown in FIGS. 3 and 4, the female screw member 182 is provided with a groove 188 as an engaging portion that opens in the outer peripheral surface thereof and extends parallel to the axial direction, and is provided in the casing 78 in the radial direction. A projecting portion 190 as a joint portion is fitted, so that the female screw member 182 can move relative to the casing 78 in the axial direction, but cannot rotate relative to the casing 78. Therefore, if the male screw member 180 is rotated, the female screw member 182 is moved in the axial direction and parallel to the rotation axis of the rotation shaft 90.

  One lever 132 of each of the three parallelogram links 130 is engaged with the female screw member 182 so as to be relatively rotatable. Each of the levers 132 is provided with a protrusion 200 that extends from a portion pivotally connected to the casing 78 by a shaft 140 to the center side of the casing 78, and has an opening 201 provided in the bottom wall of the groove 138. Through this, a groove 202 provided in the female screw member 182 is rotatably fitted. As shown in FIG. 4, a plurality of grooves 202 are provided in this embodiment. Each of these grooves 202 is opened on the outer peripheral surface of the female screw member 182 and penetrates in a direction perpendicularly intersecting the axis thereof so as to be provided at equiangular intervals.

  As shown in FIG. 3, the protrusion 200 has a relative rotation axis of the lever 132 with respect to the casing 78 and the rotation axis 90 in the rotation plane of the parallelogram link 130 including the lever 132 provided with the protrusion 200. The female screw member 182 of the groove 202 has a shape in which a part of the outer periphery of a cylinder that is orthogonal to a straight line passing through both of the rotation axes and that is centered on an axis parallel to the rotation axis of the lever 132 is cut out. A pair of side surfaces separated in a direction parallel to the rotation axis are brought into contact with each other so as to be capable of relative rotation with sliding. Therefore, if the female screw member 182 is moved in the axial direction, the protrusion 200 is rotated around the axis of the shaft 140 by the movement of the groove 202, and the lever 132 is rotated. The movement of the female screw member 182 in the axial direction is converted into the rotation of one lever 132 by the groove 202 and the protrusion 200, and the levers 132 and 134 of the three parallelogram links 130 are simultaneously rotated. The links 136 are moved all at once. Each of the levers 132 and 134 of the parallelogram link 130 is fitted in the groove 138 and is rotated along a plane including the rotation axis of the rotation shaft 90 and passing through the center in the width direction of the groove 138. The quadrilateral link group 82 is operated simultaneously while maintaining an axially symmetric state with respect to the symmetry axis. In this embodiment, the groove 202 constitutes a first engaging portion, the portion of the female screw member 182 provided with the groove 202 constitutes a movable member, the protrusion 200 constitutes a second engaging portion, and the male screw member The motion conversion device 92 is configured together with 180 and the female screw member 182. The lever 134 is provided with a notch 204 that avoids interference with the portion of the lever 132 where the protrusion 200 is provided.

  As shown in FIG. 3, the torque limiter 88 is provided between the male screw member 180 and the rotating shaft 90. The rear end portion of the male screw member 180, that is, the end portion on the shank portion 96 side of the rotating shaft 90 has a large diameter, and the first limiter member 220 is integrally provided. In this embodiment, the first limiter member 220 is provided coaxially with the male screw member 180 and always rotates together with the male screw member 180. On the annular end surface of the first limiter member 220, a corrugated uneven portion 222 is continuously formed along one circumference centered on the rotation axis of the male screw member 180, and constitutes a first engagement portion. ing. As shown in FIG. 6, the concavo-convex portion 222 has an arcuate cross-sectional shape and extends radially around the rotation axis of the male screw member 180. 226.

  As shown in FIG. 3, the second limiter member 230 is not rotatable relative to the rotary shaft 90 and is relatively unmovable relative to the first limiter member 220 in the axial direction and adjacent to the rear side (the shank portion 96 side). It is impossible to fit and is fixed. The rotation of the rotating shaft 90 constitutes an engaging portion, and is transmitted to the second limiter member 230 by fitting the pin 250 and the recess 252 constituting a relative rotation preventing device or a rotation transmitting device. The second limiter member 230 always rotates together with the rotary shaft 90, and holds a plurality of ball plungers 232 constituting the second engaging portion. The second limiter member 230 is provided with a plurality of receiving recesses 234 that are open on the surface of the first limiter member 220 on the side facing the concavo-convex portion 222 and extend in a direction parallel to the rotation axis of the rotation shaft 90 at equal angular intervals. In addition, each ball 236 is accommodated. The opening of the receiving recess 234 is slightly smaller than the diameter of the ball 236, and the ball 236 is held so that a part of the opening can protrude outward from the front end opening of the receiving recess 234. Further, the ball 236 is urged in a direction protruding from the housing recess 228 by a compression coil spring 238 as a spring which is a kind of elastic member disposed in the housing recess 234, and the projecting portion is The concave and convex portion 222 is fitted into the concave portion 224. The concavo-convex portion 222 and the ball plunger 232 face each other in the axial direction, and the first and second limiter members 220 and 230 have a plurality of balls 236 of the plurality of ball plungers 232 engaged with the plurality of recesses 224, respectively. Can be engaged with each other. In each phase of the concavo-convex portion 222, a portion where the ball 236 is fitted constitutes a first engaging portion, and a portion of the concavo-convex portion 222 constitutes the first engaging portion.

  The relative rotational torque between the first limiter member 220 and the second limiter member 230 is a set value, that is, a torque necessary for retracting the ball 236 against the biasing force of the spring 238 in each of the plurality of ball plungers 232. In the state below the sum, the ball 236 is kept in the recessed portion 224, the first and second limiter members 220 and 230 are rotated together, and the rotation of the rotating shaft 90 is transmitted to the male screw member 180. The male screw member 180 rotates together with the rotating shaft 90. If the relative rotational torque exceeds the sum of the above torques, the plurality of balls 236 are simultaneously retracted into the receiving recess 234 against the urging force of the spring 238, get over the protrusion 226, and the second limiter member 230 The rotation of the rotary shaft 90 is not transmitted to the male screw member 180 by rotating relative to the limiter member 220. The ball plunger 232 is provided in such a number that a set value (set torque) corresponding to the force with which each holding portion 176 of the three parallelogram links 130 can hold the workpiece 10 appropriately can be obtained.

  The present processing machine is controlled by a control device 270 (see FIG. 1). The control device 270 is mainly composed of a computer, and controls the work holding jig 24, the tool spindle moving device 26, the tool storage device 27, the automatic tool changer 28, the spindle rotation driving device 52, etc., and the work holder 20 The holding and releasing of the workpiece 10 by controlling the machining of the workpiece 10 by the machining tool 62 and the like are controlled.

The holding of the workpiece 10 by the work holder 20 will be described.
The workpiece holder 20 receives an unprocessed workpiece 10 from a robot (not shown) and holds it on the workpiece holding jig 24. After the processing, the workpiece holder 20 receives the processed workpiece 10 from the workpiece holding jig 24 and passes it to the robot. . Therefore, the work holder 20 is attached to the tool spindle 22 prior to machining. The tool spindle 22 is moved to the tool storage device 27 by the tool spindle moving device 26, and the processing tool 62 held by the tool spindle 22 is returned to the tool storage device 27 by the automatic tool changer 28, and the tool storage device 27 The work holder 20 accommodated in the tool 27 is held by the tool holding device of the tool spindle 22. At this time, as described above, the rotating shaft 90 of the work holder 20 is fitted into the fitting hole 97 of the tool spindle 22 in the shank portion 96, and relative rotation is achieved by fitting of the engaging protrusion 98 and the engaging recess 100. In addition to being blocked, the casing 78 is engaged with the main shaft housing 50 by the engaging device 80 so as not to rotate relative to the main shaft housing 50, so that the rotary shaft 90 can rotate together with the tool main shaft 22. Although the rotating shaft 90 rotates, the casing 78 does not rotate, and neither the parallelogram link group 82 nor the female screw member 182 rotate. In a state where the work holder 20 is accommodated in the tool accommodating device 27, the female screw member 182 is located at the retracted end position or the ascending end position, and three parallelogram links 130 are representatively shown in FIG. As described above, in both cases, the levers 132 and 134 and the link 136 are positioned at the storage position in which the longitudinal direction is substantially parallel to the rotation axis of the rotation shaft 90 and stored in the groove 138. Further, the protrusion 200 provided on the lever 132 includes the axis of the shaft 140 of the lever 132, and the axis of the shaft 140 with respect to a horizontal plane that is a plane perpendicular to the vertical rotation plane of the parallelogram link 130. It is located at the original position on the rear side (tool spindle 22 side). This storage position is also a non-holding position or a release position, and the work holder 20 is attached to the tool spindle 22 with the three parallelogram links 130 positioned at the storage position.

  Then, the work holder 20 attached to the tool spindle 22 receives the workpiece 10 from the robot. The present processing machine is a vertical type, and the work holder 20 is attached to the tool spindle 22 in a downward direction parallel to the vertical axis. Further, the workpiece 10 is held by the robot so that the opening 14 faces upward, similarly to the workpiece 10 held by the workpiece holding jig 24 shown in FIG. Located above the opening 14 of the held workpiece 10, the tool spindle 22 is lowered during holding, the work holder 20 is lowered, and the tip (lower end) of the three parallelogram links 130. Then, the holding portion 176 is caused to enter the workpiece 10 through the opening 14. The work holder 20 is lowered to a preset operation position or holding position in the vertical direction and stopped.

  In this state, the tool spindle 22 is rotated in the workpiece holding direction by the spindle rotation driving device 52. Thereby, the rotating shaft 90 is rotated, and the rotation is transmitted to the male screw member 180 via the torque limiter 88, and the male screw member 180 is rotated. When holding the workpiece 10, the ball 236 is fitted into the concave portion 224 of the concave and convex portion 222, and the male screw member 180 is rotated by the rotation of the rotary shaft 90. Thereby, the female screw member 182 is lowered, and the levers 132 and 134 of the three parallelogram links 130 are simultaneously rotated as shown in FIG. 3, and the link 136 is parallel to the rotation axis of the rotary shaft 90. It can be moved in a direction away from its rotational axis while maintaining a proper posture. The holding portions 176 of the three parallelogram links 130 are separated from each other, and a part of the part defining the opening 14 of the workpiece 10 is fitted into the groove 170 of each holding portion 176, and the engaging surface 172 is provided. Engage with the inner surface 16 of the opening 14. In this embodiment, the engaging surface 172 has a partial cylindrical surface shape, and the three engaging surfaces 172 are in linear contact with each other at three locations on the inner surface 16 in the direction perpendicular to the end surface 12, and cooperate with each other. Then, the workpiece 10 is held. The position of the lever 132 or the like when the three holding portions 176 hold the workpiece 10 is referred to as a holding position.

  If the rotation angle of the rotary shaft 90 and the male screw member 180 is increased, the moving distance of the holding portion 176 increases, and the maximum approaching / separating distance of the three holding portions 176 is changed by setting the rotation angle of the levers 132 and 134. be able to. The holding angle that is the rotation angle of the tool spindle 22 for holding the workpiece 10 by the three holding portions 176 is set in advance according to the size of the workpiece 10. The release angle, which is the rotation angle of the tool spindle 22 for causing the three holding portions 176 to release the workpiece 10, is an angle in a state where the lever 132 and the like are positioned at the storage position. The holding angle is set to such a size that the workpiece holder 20 can reliably hold the workpiece 10, and the tool spindle 22 has the engagement surface 172 of each holding portion 176 of the three parallelogram links 130 as the inner surface 16. It can be further rotated after engaging with. In this work holder 20, the male screw member 180 has a small lead angle, and the moving distance of the female screw member 182 relative to the unit rotation angle of the tool spindle 22, and hence the moving distance of the holding portion 176, is short. Even when an error occurs in the rotation stop position, the stop position error of the holding portion 176 may be small, the control accuracy of the rotation angle of the tool spindle 22 may be low, and the control can be easily performed.

  In addition, in the present embodiment, since the torque limiter 88 is provided, the workpiece 10 can be reliably held without being damaged, and the rotation angle can be controlled more easily. The rotational torque transmitted from the second limiter member 230 to the first limiter member 220 is not more than a set value until the engagement surface 172 is engaged with the inner surface 16. Furthermore, it increases rapidly by being rotated. If the set value exceeds a preset value, the ball 236 is retracted into the housing recess 234 against the biasing force of the spring 238 and gets over the projection 226, so that the second limiter member 230 moves against the first limiter member 220. The rotation torque exceeding the set value is transmitted to the male screw member 180. Therefore, even if the rotation angle of the tool spindle 22 is set to be large, the levers 132 and 134 are not forcibly rotated and the workpiece 10 is not damaged. The tool spindle 22 is stopped in a state where the tool spindle 22 is rotated by a predetermined angle, and the ball 236 is fitted into the recess 224. The concavo-convex portion 222 includes a plurality of concave portions 224 and convex portions 226, and the balls 236 are fitted into the concave portions 224 and relative to each other regardless of the phase of the first and second limiter members 220 and 230 when the rotation of the tool spindle 22 is stopped. It is possible to return to the rotational torque transmission state.

  Further, the lever 134 is provided with a plunger device 160, the lever 134 is reliably moved to the holding position, and the holding portion 176 can hold the workpiece 10 reliably. In a state where the three parallelogram links 130 are closed and the lever 132 and the like are located at the storage position, the contact member 164 of the plunger device 160 is brought into contact with the bottom surface of the groove 138 of the casing 78 and the spring The lever 134 is in a state of being retracted against the urging force, and the urging force of the spring acts on the lever 134 in the direction of moving to the holding position and opening. Therefore, when the female screw member 182 is lowered and the levers 132 and 134 and the link 136 are opened and moved from the storage position to the holding position, the lever 134 is urged in the direction to move to the holding position by the spring. The link 136 is on the side opposite to the posture when holding the workpiece 10, and is prevented from bending inward. The shaft 152 that connects the lever 134 and the link 136 so as to be relatively rotatable is orthogonal to both the axis of the shaft 142 of the lever 134 and the axis of the shaft 148 that connects the lever 132 and the link 136 so as to be relatively rotatable. Therefore, the lever 134 and the link 136 are prevented from being bent in a state where the lever 132 and the link 136 are positioned on the shaft 140 side of the lever 132. It is prevented that the situation which cannot hold | maintain and cannot hold | maintain the workpiece 10 generate | occur | produces. In the state where the holding portion 176 holds the workpiece 10, the contact member 164 is separated from the bottom surface of the groove 138 as shown in FIG. 3, and the tip thereof protrudes from the lever 134 by the bias of the spring. is there. When the lever 132 or the like is rotated to the storage position, the contact member 164 contacts the bottom surface of the groove 138, and the spring is compressed to apply a biasing force to the lever 134. The plunger device 160 constitutes a lever urging device or a pressure applying device which is a bending preventing device.

  If the workpiece holder 20 holds the workpiece 10 in this way, the tool spindle 22 is raised, and the workpiece holder 20 lifts the workpiece 10 from the robot. Then, the workpiece is moved to the workpiece holding jig 24 by the tool spindle moving device 26 and the workpiece 10 is transferred, but the workpiece 10 is moved while being suspended by the workpiece holder 20. The holding portion 176 includes a support surface 174 adjacent to the engagement surface 172 at the lower end thereof, and the support surface 174 causes a portion near the opening of the inner end surface that is the surface opposite to the end surface 12 of the workpiece 10. Can be supported from below, and even if the workpiece 10 is heavy, it can be reliably held and transported without fear of dropping.

  The workpiece holder 20 is lowered after moving to the workpiece holding jig 24, and the workpiece 10 is attached. After the workpiece 10 is held by the workpiece holding jig 24, the tool spindle 22 is rotated by the same angle in the opposite direction to that when holding the workpiece 10. Thereby, the male screw member 180 is rotated in the reverse direction, the female screw member 182 is retracted (raised), and the levers 132 and 134 of the three parallelogram links 130 are simultaneously rotated to the storage position. The two holding portions 176 are moved closer to each other and separated from the inner surface 16 to release the workpiece 10, and the lever 132 and the like are accommodated in the groove 138. After the workpiece 10 is released, the tool spindle 22 is raised and the parallelogram link 130 is pulled out of the workpiece 10 through the opening 14. Next, the work holder 20 is replaced with the processing tool 62, the work holder 20 is stored in the tool storage device 27, the processing tool 62 is attached to the tool spindle 22, and is moved by the tool spindle moving device 26 to hold the workpiece. The workpiece 10 held by the jig 24 is processed.

  After the machining is completed, the machining tool 62 is replaced with the work holder 20, and the work holder 20 is attached to the tool spindle 22. The tool spindle 22 is moved by the tool spindle moving device 26, and the work holder 20 holds the workpiece 10 after processing. This holding is performed in the same manner as when the workpiece holder 20 receives the workpiece 10 from the robot, and the workpiece 10 is removed from the workpiece holding jig 24 and transferred to the robot. Then, the unprocessed workpiece 10 is received from the robot and attached to the workpiece holding jig 24. For this reason, when the workpiece holder 20 releases the workpiece 10 delivered to the robot, the lever 132 and the like are not rotated to the storage position, and the engagement surface 172 is separated from the inner surface 16 to move the workpiece 10. The parallelogram links 82 are released and moved to a release position sufficient to exit the opening 14. The rotation angle of the tool spindle 22 in the reverse direction (workpiece release direction) is set as such. When receiving the unprocessed workpiece 10 from the robot, the lever 132 and the like are moved from the release position to the holding position, but this rotation angle is smaller than that when the lever 132 and the like are returned to the storage position, and the parallelogram link 130 is moved. Is quickly opened and closed, and the workpiece 10 is delivered quickly. After delivering the workpiece 10 to the robot, the lever 132 or the like may be returned to the storage position even when the workpiece 10 is received from the robot, or when the workpiece 10 is not received, the storage position is returned. Returned.

  In the work holder 20, for example, as shown in FIGS. 8 and 9, as the rotation angle of the levers 132 and 134 is increased, the movement distance in the direction orthogonal to the symmetry axis of the link 136 is increased, and the opening 14 is formed. A large workpiece 10 can be held. The rotation angle of the rotary shaft 90 or the tool spindle 22 is set according to the type of the workpiece 10. Even if the sizes of the openings 14 of the workpiece 10 are different, the postures of the respective holding surfaces 172 and the support surfaces 174 of the three holding portions 176 with respect to the symmetry axis do not change. Thus, the workpiece 10 can be held in a stable manner in a linear manner over the entire direction perpendicular to the workpiece 12. Further, the support surface 174 can also contact the portion in the vicinity of the opening of the inner end surface on the opposite side of the end surface 12 as a whole and support the workpiece 10. When the workpiece 10 is not held, the three parallelogram links 130 are closed as shown in FIG. 7, and the levers 132 and 134 and the link 136 can be stored in the groove 138. Can be shrunk to a compact state.

  When the workpiece 10 is attached to the workpiece holding jig 24, it is not essential to return the levers 132 and 134 and the link 136 to the storage position in order to release the workpiece 10. For example, in a work mode in which the work holder 20 continuously holds a plurality of workpieces 10 on the workpiece holding jig 24, the workpiece holder 20 holds one workpiece 10 on the workpiece holding jig 24. It is not necessary to house the lever 132 or the like in the groove 138 every time, and the levers 132 and 134 and the link 136 are moved from the holding position according to the size of the inner side surface 16 of the workpiece 10 to the inner side surface. The workpiece 10 may be released away from 16 and rotated and moved between a release position sufficient for the parallelogram link group 82 to come out of the opening 14. In this case, the tool spindle 22 or the rotary shaft 90 is rotated by an angle that moves the lever 132 or the like between the holding position and the release position that does not reach the storage position, and in both forward and reverse directions during holding and releasing. To the same angle. As the rotation angle of the rotation shaft 90 is increased, the moving distance of the holding portion 176 is increased, the workpiece 10 having a large inner surface 16 can be held, and the tool spindle 22 for holding and releasing the workpiece 10 A plurality of types of rotation angle ranges (angle ranges between the holding angle and the release angle) of the rotation shaft 90 are set according to the size of the inner surface 16.

<Second Example>
Another embodiment of the claimable invention will be described with reference to FIGS.
The processing machine of the present embodiment is a machining center, and is a so-called horizontal machine in which a tool spindle is rotatably provided around a horizontal axis, and various workpieces including the workpiece 10 are processed.

  As schematically shown in FIG. 10, the present processing machine includes a work holder 300, a tool spindle 302 (see FIG. 11) as a spindle, a workpiece holding jig 304, a tool spindle moving device 306 as a relative moving device, a tool, and the like. A storage device 307 and an automatic tool changer 308 are included. The tool spindle moving device 306 moves the tool spindle 302 in two directions orthogonal to each other in the horizontal plane (one is the X axis direction and the other is the Y axis direction) and the vertical direction (Z axis direction). Therefore, the tool spindle moving device 306 includes an X-axis moving device 310, a Y-axis moving device 312 and a Z-axis moving device 314. The X-axis moving member 316 of the X-axis moving device 310 is moved in the X-axis direction by an X-axis driving device using a servo motor (not shown) as a drive source, and the Y-axis moving member 318 of the Y-axis moving device 312 is On the X-axis moving member 316, it is moved in the Y-axis direction by a Y-axis drive device using a servo motor as a drive source. The Z-axis moving member 320 of the Z-axis moving device 314 is moved in the Z-axis direction on the Y-axis moving member 318 by a Z-axis driving device using a servo motor as a drive source. A spindle housing 330 is provided on the Z-axis moving member 320 and constitutes a non-rotating portion of the processing machine. The tool spindle 302 is held rotatably around a horizontal axis parallel to the X-axis direction. Is rotated by a spindle rotation driving device 332 using a servo motor as a driving source. These servo motors are provided with an encoder in this embodiment.

  In this embodiment, the work holding jig 304 is fixedly provided at a position adjacent to the X-axis moving device 310 in the X-axis direction, constitutes a work mounting portion, and holds and releases the workpiece 10. To do. A tool storage device 307 is mounted on the Y-axis moving member 318. In the tool storage device 307, a plurality of types of processing tools 342 and the work holder 300 are stored. An automatic tool changer 308 is mounted on the Z-axis moving member 320 together with the tool spindle 302. The automatic tool changer 308 is provided so as to be rotatable around a horizontal axis, and has a holding arm 348 as a holding member provided with holding parts 346 at both ends, an arm rotation driving device (not shown) for rotating the holding arm 348, and An arm moving device (not shown) that moves the holding arm 348 in a direction parallel to the rotation axis, and the like. By rotating and moving the holding arm 348, a machining tool is provided between the tool spindle 302 and the tool storage device 307. 342 and the work holder 300 are delivered. In the present processing machine, the workpiece 10 is carried in and out by a robot (not shown). The work holder 300 is attached to the tool spindle 302 and transfers the workpiece 10 to and from the robot and the workpiece holding jig 304.

The work holder 300 will be described.
As shown in FIG. 11, the work holder 300 includes a casing 400 as a main body member, an engagement device 402, two holding members 404, a drive device 408, and a torque limiter 410. The drive device 408 includes a rotation shaft 412 and a motion conversion device 414. The casing 400 holds the rotary shaft 412 via a plurality of bearings 416 so that the rotary shaft 412 can be relatively rotated around its axis and is not relatively movable in the axial direction. The rotating shaft 412 is provided with a shank portion 418 whose diameter decreases linearly toward the protruding end of the protruding portion from the casing 400, and the tapered fitting hole of the tool spindle 302 is the same as the rotating shaft 90. While being fitted to 420, the relative rotation with respect to the tool spindle 22 is prevented by the fitting of the engaging protrusion 426 and the engaging recess 428.

  In the present embodiment, the casing 400 includes a first member 440 and a second member 442 that are assembled and fixed together. The first and second members 440 and 442 function as an integral casing after assembly. The casing 400 is engaged with the main shaft housing 330 by the engaging device 402 to be prevented from rotating and allows the rotation shaft 412 to rotate. The engaging device 402 is configured in the same manner as the engaging device 80, and the same reference numerals are given to the constituent elements having the same action to show the corresponding relationship, and the description thereof is omitted.

  The first member 440 constituting the casing 400 has a generally cylindrical shape, and the second member 442 has a shape in which a part of a disk having a diameter larger than the outer diameter of the first member 440 is cut out. The one member 440 is fixed concentrically while closing the opening. The casing 400 is formed with lever grooves 468 at two locations separated in the diameter direction. Each of these lever grooves 468 is formed in the first member 440, and is formed in the groove 470 that opens to the outer peripheral surface and the front end surface thereof, and in the second member 442, penetrates the second member 442 in the axial direction, and the front end surface thereof And a groove 480 that opens to the outer peripheral surface. The grooves 470 and 480 have the same width, and a lever groove 468 is formed across the first and second members 440 and 442.

  The lever 406 is fitted in each of the two lever grooves 468, and the two levers 406 are respectively rotated by the shaft 472 to the casing 400 and the rotation shaft 412 at one end fitted to the groove 470 side. It is an axis that intersects perpendicularly with the axis at right angles, is vertical, and is mounted so as to be rotatable around axes parallel to each other. The lever 406 protrudes from the front end surface of the casing 400 through the groove 480 and is guided to rotate mainly by the groove 480. The groove 480 forms a guide.

  A holding member 404 is attached to each of the free ends of the two levers 406 and the protruding ends from the casing 400. As shown in FIGS. 11 and 12, each of these two holding members 404 includes a support plate 490 as a support member and a protruding member 492 as an engagement member in this embodiment. The support plate 490 has a longitudinal shape, and the projecting member 492 has a circular outer periphery in the cross-sectional shape. As shown in FIGS. 12 and 13, mounting portions provided at the free ends of the two levers 406, respectively. They are fixed together at 494 by bolts 496 which are a kind of fixing means, and are directly fixed to each other. As shown in FIG. 12, the second member 442 is cut out at a notch surface 500 parallel to the plane of the outer periphery of the second member 442 that is separated in a direction perpendicular to the plane including the two lever grooves 468. As shown in FIG. 12 and FIG. 13, the mounting portions 494 of the two levers 406 are respectively perpendicular to the longitudinal direction from the free end of the lever 406, and the rotation axis of the rotation shaft 412. It extends in a direction perpendicular to the three-dimensional intersection, and protrudes beyond one notch surface 500. A portion that is orthogonal to the plane including the two lever grooves 468 and that is separated from the notch surface 500 is also notched in a notch surface 501 that is parallel to the notch surface 500.

  At each of these protruding ends, the mounting surface 502 is provided in a state of being positioned on a horizontal plane parallel to the rotation axis of the rotating shaft 412, and the support plate 490 is placed on each mounting surface 502, respectively. The protruding member 492 is mounted in such a posture that its axis is perpendicular to the plate surface of the support plate 490 (vertical in this embodiment), and can be attached to and detached from the mounting portion 494 together by appropriate fixing means such as a bolt 496. It is fixed to. As shown in FIG. 13, the support plate 490 is detachably fixed to the mounting portion 494 by another bolt 503 as a fixing means. In each of the two support plates 490, the surface opposite to the attachment portion 494 forms a support surface 504, and the outer peripheral surface of the protruding member 492 forms an engagement surface 506 perpendicular to the support surface 504. These two support surfaces 504 are parallel to the axis of the rotating shaft 412 and are located on a horizontal plane, and the casing 400, the support plate 490, and the driving device 408 (including two levers 406) are arranged on one side of the plane. Is arranged. With respect to the support plate 490, a portion other than the portion constituting the support surface 504 is disposed on one side of one plane where the support surface 504 is located. Further, as shown in FIG. 11, the free end portion of the lever 406 is bent in one plane with respect to the base end portion, and the support plate 490 is fixed in a posture inclined with respect to the base end portion of the lever 406. The two support plates 490 are fixed in such a manner that their tip ends (the free end side of the lever 406) approach each other.

  The two projecting members 492 are fixed in a state of projecting from each of the two support surfaces 504, and each projecting end of each projecting member 492 extends outward in the radial direction as shown in FIG. A flange portion 510 is provided, and an annular groove 512 is provided between the protruding member 492, the support plate 490, and the flange portion 510.

In this embodiment, the motion conversion device 414 includes a male screw member 180, a female screw member 182, a protrusion 200, a groove 202, and two levers 406. The motion conversion device 414 is configured in the same manner as the motion conversion device 92 and has the same function. Constituent elements formed are denoted by the same reference numerals to indicate the corresponding relationship, and detailed description thereof is omitted.
Each of the two levers 406 is engaged with a female screw member 182 so as to be relatively rotatable, as shown in FIG. Each of these levers 406 is provided with a protrusion 200 that extends from a portion rotatably connected to the casing 400 by a shaft 472 to the center side of the casing 400 through an opening 520 provided in the bottom wall of the groove 470. In addition, each of the two grooves 202 provided in the female screw member 182 is rotatably fitted. As shown in FIG. 12, each of the two grooves 202 opens in the outer peripheral surface of the female screw member 182, and is in a direction that three-dimensionally intersects the axis at right angles and in a direction parallel to the rotation axis of the lever 406. It penetrates and is provided in parallel with each other.

  As shown in FIG. 11, the protrusion 200 is orthogonal to a straight line passing through both the rotation axis of the lever 406 and the rotation axis of the rotation shaft 412 in the rotation plane of the lever 406 (horizontal plane in this embodiment). A part of the outer periphery of a cylinder centered on an axis parallel to the rotation axis of the lever 406 is cut out, and a pair of side surfaces separated in a direction parallel to the axis of the female screw member 182 of the groove 202 are provided. Each is contacted so as to be capable of relative rotation with sliding. Therefore, when the female screw member 182 is moved in the axial direction, the protrusion 200 is rotated about the axis of the shaft 472 by the movement of the groove 202, and the lever 406 is rotated. The pair of levers 406 are simultaneously rotated by the movement of the female screw member 182 in the axial direction, and the two support plates 490 are moved in the directions in which the two protruding members 492 approach and separate from each other. In this embodiment, the groove 202 constitutes a first engaging portion, the portion of the female screw member 182 provided with the groove 202 constitutes a movable member, the protrusion 200 constitutes a second engaging portion, and the male screw member 180, the female screw member 182 and the two levers 406 constitute a motion conversion device 414.

  The torque limiter 410 is provided between the male screw member 180 and the rotating shaft 412. The torque limiter 410 is also configured in the same manner as the torque limiter 88, and the same reference numerals are given to components having the same action to indicate the corresponding relationship. In the torque limiter 410, the first limiter member 220 is integrally provided at the end of the male screw member 180 opposite to the shank portion 418, and the second limiter member 230 is on the front end side or front side of the first limiter member 220. It is fitted to the rotating shaft 412 (on the side opposite to the shank portion 418), is detachably fixed by appropriate fixing means such as bolts, and is rotatably held by the casing 400 by a bearing 248. The front end of the rotating shaft 412 is rotatably supported by the casing 400 via the second limiter member 230, and the second limiter member 230 always rotates together with the rotating shaft 412. Further description of the torque limiter 410 is omitted.

  This processing machine is controlled by a control device 550 (see FIG. 10). The control device 270 is mainly composed of a computer, and controls the work holding jig 304, the tool spindle moving device 306, the tool storage device 307, the automatic tool changer 308, the spindle rotation driving device 332, etc. The holding and releasing of the workpiece 10 by controlling the machining of the workpiece 10 by the machining tool 342 and the like are controlled.

The holding of the workpiece 10 by the work holder 300 will be described.
The workpiece holder 300 receives an unprocessed workpiece 10 from a robot (not shown) and holds it on the workpiece holding jig 304. After the processing, the workpiece holder 300 receives the processed workpiece 10 from the workpiece holding jig 304 and passes it to the robot. . Therefore, the work holder 300 is attached to the tool spindle 302 prior to machining. The tool spindle 302 is moved to the tool storage device 307 by the tool spindle moving device 306, and the processing tool 342 held by the tool spindle 302 is returned to the tool storage device 307 by the automatic tool changer 308. The work holder 300 accommodated in 307 is held by the tool holding device of the tool spindle 302. At this time, as described above, the rotating shaft 412 of the work holder 300 is fitted in the fitting hole 420 of the tool spindle 302 in the shank portion 418 so as not to be relatively rotatable, and the casing 400 is driven by the engaging device 402 by the spindle housing 330. , The rotation shaft 412 can be rotated together with the tool spindle 302. The rotating shaft 412 rotates, but the casing 400 does not rotate, and the holding member 404, the lever 406, and the female screw member 182 do not rotate. When the work holder 300 is housed in the tool housing device 307, the two levers 406 are closed, and the entire longitudinal direction is substantially parallel to the rotation axis of the rotation shaft 412 as shown in FIG. It is stored in the groove 470 and the two holding members 404 are positioned at the storage position closest to each other. This storage position is also a non-holding position or a release position, and the tool spindle 302 is attached to the work holder 300 with the lever 406 and the like positioned at the storage position. This processing machine is a horizontal type, and the work holder 300 is held in such a posture that the rotation shaft 412 is horizontal and horizontal, and the support surfaces 504 of the two holding members 404 are horizontal and upward, and the two protruding members 492 are Each protrudes upward from the support surface 504.

  Then, the tool spindle 302 is moved by the tool spindle moving device 306, and the workpiece holder 300 held by the tool spindle 302 receives the workpiece 10 from the robot. At this time, the two levers 406 are closed and stored in the lever groove 468 in a posture substantially parallel to the rotation axis of the rotation shaft 412 as shown in FIG. Yes. The workpiece 10 is held by the robot in a state where the opening 14 and the end face 12 face downward, similarly to the workpiece 10 held by the workpiece holding jig 304 shown in FIG. Moved by the moving device 306, the two holding members 404 and the lever 406 are made to enter the lower side of the workpiece 10, and the protruding member 492 enters the opening 14 in a direction parallel to the axis of the protruding member 492, When the two levers 406 are opened, the lever 406 is moved to a position that engages with the inner side surface 16 and is set to a predetermined engagement position (also an operation position and a holding position).

  In this state, the tool spindle 302 is rotated in the workpiece holding direction by the spindle rotation driving device 332. Thereby, the rotating shaft 412 is rotated, and the rotation is transmitted to the male screw member 180 via the torque limiter 410, and the male screw member 180 is rotated. When holding the workpiece 10, the ball 236 is fitted in the concave portion 224 of the concave and convex portion 222, and the male screw member 180 is rotated by the rotation of the rotating shaft 412. Thereby, the female screw member 182 is advanced, for example, as shown in FIG. 14, the two levers 406 are simultaneously rotated symmetrically to protrude from the casing 400, and the two holding members 404 are rotated by the rotating shaft 412. The two projecting members 492 are separated from each other and opened. Then, the part defining the opening 14 of the workpiece 10 is fitted into the groove 512, and the engaging surfaces 506 of the projecting members 492 of the two holding members 404 are in contact with the two portions of the inner surface 16, respectively. Hold. The positions of the holding member 404 and the lever 406 when the two holding members 404 hold the workpiece 10 are referred to as holding positions (the holding positions in the approaching / separating direction of the two holding members 404).

  If the rotation angle of the rotating shaft 412 and the male screw member 180 is increased, the moving distance of the holding member 404 is increased, and the maximum approaching / separating distance between the two holding members 404 can be changed by setting the rotation angle of the lever 406. it can. A holding angle that is a rotation angle of the tool spindle 302 for holding the workpiece 10 on the two holding members 404 is set in advance according to the size of the workpiece 10. The release angle, which is the rotation angle of the tool spindle 302 for causing the two holding members 404 to release the workpiece 10, is an angle in a state where the lever 406 and the like are positioned at the storage position. The holding angle is set to such a size that the work holder 300 can reliably hold the workpiece 10. Since the male screw member 180 has a small lead angle, even if an error occurs in the rotation stop position of the tool spindle 302, the stop position error of the holding member 404 can be reduced. Further, the torque limiter 410 acts in the same manner as the torque limiter 88, and the work holder 300 securely holds the work piece 10 and the like without damaging them.

  If the workpiece holder 300 holds the workpiece 10 in this way, the tool spindle 302 is moved by the tool spindle moving device 306, and the workpiece 10 is removed from the robot. Then, the tool spindle 302 is moved to the workpiece holding jig 304, and the workpiece 10 is attached to the workpiece holding jig 304 by the workpiece holder 300. The workpiece holder 300 holds the workpiece 10 from below, As shown in FIG. 13, the portion of the workpiece 10 that defines the opening 14 is in the groove 512, and the support surface 504 is positioned below the end surface 12. Therefore, the workpiece holder 300 can contact the vicinity of the opening of the end surface 12 on the two support surfaces 504 to support the workpiece 10 from below, and even if the workpiece 10 is heavy, it can be held without fear of dropping. Can be transported. In particular, the work holder 300 includes two support members 404 each having a support surface 504, and the support plate 490 has a longitudinal shape and is fixed to the lever 406 while being inclined. While being enlarged, it is made to contact the end surface 12 in the largest possible area, and can support the workpiece 10 stably. The end surface 12 is a supported surface, and the inner side surface 16 is a surface extending in a direction orthogonal to the supported surface. Of these, the portions where the two projecting members 492 are engaged are two oppositely directed two supported surfaces. An engagement surface is formed.

  The workpiece holder 300 is lowered after moving to the workpiece holding jig 304, and the workpiece 10 is attached. After the workpiece 10 is held by the workpiece holding jig 304, the tool spindle 302 is rotated by the same angle in the opposite direction to that when the workpiece 10 is held. As a result, the male screw member 180 is rotated in the opposite direction, the female screw member 182 is retracted, the two levers 406 are simultaneously rotated to the storage position, and the two projecting members 492 are brought closer to each other, thereby causing the inner surface. Move away from 16 and release workpiece 10. Then, the tool spindle 302 is lowered by the Z-axis moving device 314 and is moved in the X-axis and Y-axis directions by the X-axis moving device 310 and the Y-axis moving device 312, so that the work holder 300 is removed from the workpiece 10. At the same time, the tool spindle 302 is moved by the tool spindle moving device 306, and the work holder 300 is moved to the tool storage device 307. Next, the workpiece holder 300 is replaced with the machining tool 342, the machining tool 342 is held by the tool holding device instead of the workpiece holder 300, the tool spindle 302 is moved by the tool spindle moving device 306, and the workpiece holding jig 304 is moved. The workpiece 10 held by the machining tool 342 is machined by the machining tool 342. The processing tool 342 processes, for example, the outer surface of the workpiece 10 or the inner surface of a hole opened on the outer surface.

  After the processing is completed, the processing tool 342 is replaced with the work holder 300, the work holder 300 is held by the tool holding device, the workpiece 10 after processing is held, removed from the workpiece holding jig 304, and handed to the robot. Then, the unprocessed workpiece 10 is received from the robot and attached to the workpiece holding jig 304. Reception of the workpiece 10 after processing from the workpiece holding jig 304 and delivery to the robot are performed in the same manner as reception of the workpiece 10 from the robot and attachment to the workpiece holding jig 304.

  In the work holder 300, as shown in FIG. 15, as the rotation angle of the rotation shaft 412 is increased and the rotation angle of the lever 406 is increased, the moving distance of the holding member 404 in the radial direction is increased, and the opening 14 Can hold a large workpiece 10. The rotation angle of the rotary shaft 412 or the tool spindle 302 is set in advance according to the type of the workpiece 10. When the workpiece 10 is not held, the two levers 406 are closed and stored in the lever groove 468 as shown in FIG. 11, and the work holder 300 is contracted to be in a compact state.

  The angle formed by the longitudinal support member and the longitudinal direction of the lever may be changeable. For example, in the above embodiment, the support plate 490 is fixed to the mounting portion 494 only by the bolt 496, the screwing of the bolt 496 is loosened, and the support plate 490 is rotated around the axis of the bolt 496 to Change the angle with the direction.

<Third embodiment>
Still another embodiment of a work holder that is attached to a tool spindle of a processing machine and holds a workpiece will be described with reference to FIGS.
Similar to the work holder 20, the work holder 600 is attached to a vertical machining center and holds the work piece 610. Similar to the workpiece 10, the workpiece 610 includes an opening 614 that opens to the outer end surface 612 that is one surface, and is held by the workpiece holder 600 on the inner side surface 616 thereof.

  The work holder 600 includes a casing 620 as a main body member, an engaging device 622, a plurality of holding members 624, a driving device 626, and a torque limiter 628 in this embodiment. The drive device 626 includes a rotation shaft 630 and a motion conversion device 632. The work holder 600 is attached to the tool spindle 22 and the spindle housing 50 of the vertical processing machine in the same manner as the work holder 20. Constituent elements having the same functions as those of the work holder 20 are denoted by the same reference numerals to indicate the corresponding relationship, and description thereof is omitted or briefly described.

  Each of the three holding members 624 has a longitudinal block shape as shown in FIGS. 16 and 17. The casing 620 has a cylindrical shape, and the rotary shaft 630 is held in a rear portion thereof via a bearing 636 so as to be relatively rotatable and not relatively movable in the axial direction, and a holding member 624 is held at a front end portion or a front end portion. ing. In the front end portion of the casing 620, a plurality of fitting holes 640 are formed through the peripheral wall in the radial direction, three in the present embodiment, and equiangular intervals are provided, and a holding member 624 is attached to each fitting hole 640. They are fitted so that they cannot move relative to each other and can move relative to each other in the radial direction. The three holding members 624 are arranged symmetrically with respect to the rotational axis of the rotational shaft 630 as an axis of symmetry, and each outer surface has a partially cylindrical engaging surface 642 with the symmetrical axis as the axis, respectively. A flat support surface 644 extending from the front end side of the engagement surface 642 perpendicular to the axis of symmetry and outward is provided.

  As shown in FIG. 16, cam followers 650 are respectively provided at two positions separated in the axial direction of the symmetry axis on the inner surface (the surface on the symmetry axis side) side of the holding member 624. In the present embodiment, each of the two cam followers 650 is a conical surface having a symmetry axis as a center line, and is an engaging surface that forms part of a conical surface whose diameter increases toward the rear side of the casing 620. It protrudes from the inner peripheral surface of the casing 620 toward the axis of symmetry and is engaged with two cam surfaces 658 of the cam 656, respectively. The cam 656 has an axial shape with a circular cross-sectional shape, and is held in a casing 620 so as not to be relatively rotatable and movable on a symmetric axis on which three holding members 624 are arranged. The relative rotation of the cam 656 relative to the casing 620 includes a recess 660 as an engaging portion provided in parallel to the axial direction of the cam 656 and a protrusion 662 as an engaging portion provided in the casing 620. Blocked by 664, axial relative movement is allowed.

  A cam surface 658 is formed at each of two locations separated from each other in the axial direction of the cam 656 by forming a surface that forms a part of a conical surface with the axis as the center line and the diameter increasing toward the rear. The cam surface 658 is inclined with respect to the symmetry axis, and each of the two cam followers 650 of the three holding members 624 is an elastic that is a kind of biasing means fitted to the outer peripheral surface of the casing 620. A spring 670 as a member is pressed against and engaged with the cam surface 658. In this embodiment, the spring 670 is formed by connecting both ends of one ring-shaped portion constituting the tension coil spring to form an endless ring, and the spring 670 is elastically deformed and extended. The two holding members 624 are fitted in grooves 674 formed in the circumferential direction. The three holding members 624 are urged by the spring 670 in a direction toward the rotation axis of the rotation shaft 630, and the two cam followers 650 are pressed against the cam surface 658, respectively. The casing 620 is also provided with an annular groove 672 that opens to the outer surface thereof, and a portion other than the portion fitted to the holding member 624 of the spring 670 is fitted into the groove 672 and abuts against the bottom surface of the groove 672. ing.

  A male screw member 690 is integrally provided at the rear end portion of the cam 656, and is screwed into a female screw member 692 that is relatively rotatable and axially immovable by the casing 620. The female screw member 692 rotates. By being rotated by the shaft 630, the male screw member 690 is moved in the axial direction, and the cam 656 is moved forward and backward. In this embodiment, the male screw member 690 constitutes a second screw member, the female screw member 692 constitutes a first screw member, and these constitute a rotation / linear motion conversion mechanism, together with a cam 656, a cam follower 650, and a spring 670. A motion conversion device 632 is configured.

  The torque limiter 628 includes a first limiter member 710 provided integrally with the female screw member 692, and a second limiter member 712 that is held on the rotating shaft 630 so as not to be relatively rotatable and relatively unmovable in the axial direction. The second limiter member 712 is also held by the casing 620 so as to be relatively rotatable. The first limiter member 710 and the second limiter member 712 are opposed to each other in the axial direction, and an uneven portion 714 and a plurality of ball plungers 716 are provided to face each other. The concavo-convex portion 714 and the ball plunger 716 are configured in the same manner as the concavo-convex portion 222 and the ball plunger 232, and the same reference numerals are given to the constituent elements having the same action, and the description is omitted. .

The holding / release of the workpiece 610 by the workpiece holder 600 will be described.
In the state in which the workpiece holder 600 does not hold the workpiece 610, as shown in FIG. 18, the cam 656 is positioned at the retracted end position, and the three holding members 624 are retracted to the most symmetrical axis side. Almost stored. The work holder 600 held vertically by the tool holding device is moved by the tool spindle moving device, and the holding member 624 is caused to enter the opening 614 as shown in FIG. The holding member 624 is advanced until the support surface 644 passes through the opening 14 and is positioned in the casing 620, and the rotation shaft 630 is rotated by a predetermined angle in the workpiece holding direction. As a result, the cam 656 is advanced, and the three holding members 624 are directed outward in the radial direction of the casing 630 against the urging force of the spring 670 and separated from each other by the cam action of the cam surface 658. The engagement surface 642 is engaged with the inner surface 616 to hold the workpiece 610. The work holder 600 is moved by the tool spindle moving device 26 in a state where the work piece 610 is hung, but the holding member 624 includes a support surface 644 and can support the work piece 610 at three positions from below. It can be transported without falling. The operation of the torque limiter 628 is the same as that of the torque limiter 88, and a description thereof will be omitted.

  When the workpiece holder 610 releases the workpiece 610, the rotation shaft 630 is rotated in the reverse direction at the same angle as when the workpiece is held, and the cam 656 is retracted. The holding member 624 is moved toward the axis of symmetry in the radial direction of the casing 630 by the bias of the spring 670, and the engagement surface 642 is separated from the inner side surface 616 to release the workpiece 610.

  As the rotation angle of the rotation shaft 630 is increased and the movement distance of the cam 656 is increased, for example, as shown in FIG. 19, the movement distance of the holding member 624 is increased and the workpiece 610 having a large opening 14 is held. Can do.

  The work holders 20 and 600 of the first and third embodiments may be attached to a horizontal machining center to hold the workpiece.

  The work holder 300 of the second embodiment may be attached to a vertical machining center (processing machine) to hold the workpiece. In this case, the work holder, for example, has a support surface vertical, and the two engaging members approach and separate from each other in the vertical plane to hold and release the workpiece. Although it does not support, the shift | offset | difference and inclination of a workpiece are controlled from the side, and the holding | maintenance of the workpiece by two engaging members is assisted.

  Further, when the workpiece holder 300 of the second embodiment is attached to the horizontal machining sensor and holds the workpiece, the workpiece is placed in a state where the support member is positioned above the engagement member and the support surface faces downward. It may be held. The workpiece holder may be held by the tool holding device so that the workpiece is suspended from above. In this case, the supporting surface is engaged with the upwardly supported surface of the workpiece from the upper surface to regulate its inclination and displacement, and is transported without falling.

  Furthermore, the tool spindle may be rotated around an axis other than the vertical axis and the horizontal axis.

  Further, as in the work holder 300 of the second embodiment, in a work holder having two levers and holding members held by the levers, and holding and releasing the workpiece by approaching and separating the holding members. One of the two holding members does not have a support member but has only an engagement member, and the work holder may have only one support member.

  Further, in each of the above-described embodiments, the work holder 20 or the like is configured such that a plurality of holding portions or holding members are separated from each other to hold the workpiece 10 or the like and are brought close to each other to release the workpiece 10 or the like. However, the workpieces 10 and the like may be held close to each other and may be separated from each other to release the workpieces 10 and the like. The workpiece holder holds the workpiece holding portion from the outside. In this case, the shape of the portion of the holding member that holds the workpiece is, for example, a shape corresponding to the shape of the held portion of the workpiece. For example, the holding member is provided with a concave portion having a triangular cross-sectional shape, and two surfaces of the concave portion that intersect each other are used as engaging surfaces and are held in contact with the outer side surface of the held portion as the held surface.

  Further, at least a part of the workpiece holding / release operation of the plurality of holding members and at least a part of the relative movement between the work holder and the work holding jig by the relative movement device may be performed in parallel. Good.

  Furthermore, the relative movement device may be a device that moves the workpiece attachment portion, or may be a device that moves both the tool spindle and the workpiece attachment portion.

  Furthermore, the claimable invention is a processing machine other than a machining center, and can be applied to a processing machine including a work holder and a work holder of the processing machine.

  Although several embodiments of the claimable invention have been described in detail above, these are merely examples, and the claimable invention includes the aspects described in the above [Aspect of the Invention]. The present invention can be implemented in various forms based on the knowledge of the trader.

It is a front view which shows the processing machine which is an Example of this claimable invention. It is a side view which shows the said processing machine. It is a front view (partial cross section) which shows the work holder of the said processing machine. It is a bottom view which shows the said work holder. It is a side view which shows the said work holder. It is an expanded view which shows the uneven | corrugated | grooved part and ball | bowl of the torque limiter of the said work holder. It is a front view (part cross section) which shows a part of state in which the said work holder does not hold | maintain a workpiece. It is a figure explaining holding of another work piece by the above-mentioned work holder. It is a figure explaining holding of another workpiece by the above-mentioned work holder. It is a front view which shows the processing machine which is another Example of this invention which can be claimed. It is a top view (partial cross section) which shows the work holder of the processing machine shown in FIG. It is a side view (partial cross section) which shows the work holder shown in FIG. It is a front view (partial cross section) which shows the work holder shown in FIG. It is a figure explaining holding | maintenance of the workpiece by the work holder shown in FIG. It is a figure explaining holding | maintenance of another workpiece by the workpiece holder shown in FIG. It is a front view (partial cross section) which shows the work holder of the processing machine which is another Example of this invention which can be claimed. It is a bottom view which shows the work holder shown in FIG. It is a figure which shows the state which does not hold | maintain the workpiece of the work holder shown in FIG. It is a figure explaining holding | maintenance of another workpiece by the workpiece holder shown in FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10: Workpiece 12: End surface 14: Opening 16: Inner side surface 20: Work holder 22: Tool spindle 24: Workpiece holding jig 26: Tool spindle moving device 27: Tool storage device 28: Automatic tool changer 50: Spindle housing 62: Processing tool 78: Casing 82: Parallelogram link group 86: Drive device 88: Torque limiter 90: Rotating shaft 92: Motion converter 130: Parallelogram link 132, 134: Lever 136: Link 172: Engagement surface 174: Support surface 180: Male screw member 182: Female screw member 184: Male screw portion 186: Female screw portion 200: Protruding portion 202: Groove 220: First limiter member 222: Concavity and convexity 224: Concavity 226: Protruding portion 230: Second limiter member 232: Ball plunger 234: receiving recess 236: ball 238: compression coil spring 300: work holder 302: tool spindle 304: work holding jig 306: tool spindle moving device 307: tool receiving device 308: automatic tool changer 330: spindle housing 342: Processing tool 404: Holding member 406: Lever 408: Drive device 410: Torque limiter 412: Rotating shaft 414: Motion conversion device 490: Support plate 492: Projection member 504: Support surface 506: Engagement surface 600: Work holder 610 : Workpiece 612: End surface 614: Opening 616: Inner surface 624: Holding member 626: Drive device 628: Torque limiter 630: Rotating shaft 632: Motion conversion device 642: Engagement surface 650: Cam follower 656: Cam 658: Cam surface 670: Tension spring 690: Male screw member 692: Female screw member 710: First limiter member 712: Second limiter member 714: Concavity and convexity 716: Ball plunger

Claims (5)

A rotating shaft that is rotatably and detachably attached to the main shaft of the processing machine;
A main body member that holds the rotation shaft so as to be relatively rotatable and is engaged with a non-rotating portion of the processing machine;
A plurality of holding members provided so as to be relatively movable with respect to the main body member and holding the workpiece in cooperation with each other;
A motion conversion device that is provided between the rotating shaft, the main body member, and the holding member, and converts relative rotation of the rotating shaft with respect to the main body member into a motion of holding and releasing the workpiece of the holding member. A work holder that holds the workpiece for attaching to and detaching from the work holding portion of the processing machine,
The motion conversion device is
A first screw member that rotates with the rotating shaft;
A second screw member that is held by the main body member so as not to rotate relative to the main body and that can move relative to the axial direction, and is screwed with the first screw member, the second screw member moving relative to the main body member in the axial direction; Is converted into the motion of the plurality of holding members. The first screw member is held by the main body member so as to be relatively rotatable, and torque less than a set value is transmitted between the first screw member and the rotary shaft, but torque exceeding the set value is not transmitted. The work holder according to claim 1, further comprising a torque limiter. The torque limiter is
A first limiter member that always rotates with the first screw member;
A second limiter member that always rotates with the rotating shaft;
One of the first limiter member and the second limiter member is provided with a plurality of first engaging portions provided on a circumference around one rotation axis, and the first limiter member and the second limiter member. A second engagement portion that is held on the other side and elastically engages with the first engagement portion, and the relative rotational torque between the first limiter member and the second limiter member is equal to or less than the set value. The workpiece holder according to claim 2, wherein the second engaging portion includes a member that does not come off from the first engaging portion and comes off when exceeding the set value. 4. The work holder according to claim 3, wherein the first engaging portion is constituted by a part of a corrugated uneven portion formed continuously along the circumference of the circle. The second engaging portion is
An accommodating recess provided in the other of the first limiter member and the second limiter member;
A ball that is held so that at least a part thereof protrudes from the front end opening of the housing recess;
The work holder according to claim 3, further comprising an elastic member that is disposed in the housing recess and urges the ball in a protruding direction.

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