JP2001062615A5 - - Google Patents

Description

Patent application title: Workpiece holding apparatus and processing method using the same
[Claim of claim]
1. A plurality of radial gripping members for gripping a workpiece from its radial direction, an abutting member against which the rear end of the workpiece is axially butted, and the abutting member An axial gripping member for gripping the workpiece in the axial direction with the contact member by abutting from the front to the workpiece is provided on the main shaft, and the radial gripping member is used to grip the workpiece Radial drive means for switching between the grip position and the release position for releasing the work, and the radial drive means operating independently, the axial gripping member being in contact with the axial gripping member It comprises: a holding position for holding the work in the axial direction with the member; and an axial drive means for moving the work between a holding position for holding the work from the holding position and a front position.An inner shaft drive means for displacing the inner shaft and the outer cylinder on the central shaft of the main shaft so as to be axially movable independently of each other, and for moving the inner shaft in the axial direction; A drive transmission mechanism which causes the radial gripping member to switch between the gripping position and the releasing position in accordance with axial movement of the shaft, an outer cylinder driving means for moving the outer cylinder in the axial direction, and a shaft of the outer cylinder It has a connecting member for connecting the outer cylinder and the axial gripping member so that the axial gripping member moves between the holding position and the withdrawal position with the movement of the direction.A workpiece gripping device characterized by
2. The workpiece gripping device according to claim 1, wherein when the axial gripping member is retracted to the retracted position, the axial gripping member is retracted radially outward from the front of the workpiece. A workpiece gripping device characterized in that the axial drive means is configured to rotate the axial gripping member.
3. A workpiece holding apparatus according to claim 1 or 2At least one of the inner shaft driving means and the outer cylinder driving means is constituted by a fluid pressure cylinder, and a cylinder bore of the fluid pressure cylinder is formed in the main shaftA workpiece gripping device characterized in that.
Claim 41 or 2In the described workpiece gripping device,The inner shaft drive means and the outer cylinder drive means are constituted by two fluid pressure cylinders independent of each other, and the cylinder bores of both fluid pressure cylinders are formed in the main shaftA workpiece gripping device characterized in that.
Claim 54In the described workpiece gripping device,Both cylinders are formed at both ends of the main shaftA workpiece gripping device characterized in that.
Claim 61 to 5In the workpiece gripping device according to any one ofDuring machining of the workpiece, the radial driving means is first operated to switch the radial gripping member from the release position to the gripping position, and after the end face machining of the workpiece in this state is finished, the axial driving is performed Means is operated to move the axial gripping member from the stand-by position to the gripping position, and then the radial driving means is actuated to switch the radial gripping member from the gripping position to the release position.A workpiece gripping device characterized in that.
Claim 71 to 5In the workpiece gripping device according to any one ofWhen machining the workpiece, the radial drive means is first operated to switch the radial gripping member from the release position to the gripping position, and the axial drive means is actuated to move the axial gripping member from the retreat position The radial direction driving means is moved to the holding position and the radial direction driving means is operated to switch the radial direction holding member from the holding position to the release position, and after the circumferential surface processing of the work in this state is finished. Is operated to switch the radial gripping member from the release position to the gripping position and then operate the axial driving means to switch the axial gripping member from the gripping position to the retracted position.A workpiece gripping device characterized in that.
[Claim 8]A machining method using the workpiece gripping device according to any one of claims 1 to 5, wherein the radial gripping member is switched from the release position to the gripping position by the operation of the radial direction driving means, and the radial gripping is performed. After the workpiece is gripped from the radial direction by the member and the end surface processing of the workpiece is performed in this state, the axial gripping member is moved from the stand-by position to the gripping position by the operation of the axial drive means After the workpiece is held in the axial direction by the direction gripping member and the contact member, the radial direction gripping member is returned to the release position by the operation of the radial direction driving means, and the peripheral surface processing of the workpiece is performed in this state. A processing method using a workpiece holding device characterized by performing.
Claim 91 to 5And the radial direction gripping member is switched from the release position to the grasping position by the operation of the radial direction driving means.The centering of the workpiece is performed, and the axial gripping member is moved from the retracted position to the gripping position by the operation of the axial drive means, and the workpiece is gripped in the axial direction by the axial gripping member and the contact member. After that, the radial direction gripping member is returned to the release position by the operation of the radial direction driving means, and after the peripheral surface processing of the work is performed in this state, the radial direction gripping member is performed by the operation of the radial direction driving means Is switched from the release position to the gripping position and the workpiece is gripped in the radial direction by the radial gripping member, and then the axial gripping member is returned to the withdrawal position by the operation of the axial drive means. Perform end face processing of objectsA processing method using a workpiece gripping device characterized in that.
Detailed Description of the Invention
[0001]
Field of the Invention
The present invention relates to a workpiece gripping device for gripping a workpiece in a machine tool and a processing method using the same.
[0002]
[Prior Art]
Generally, in a machine tool for processing the inner and outer peripheral surfaces and end faces of a workpiece, a workpiece gripping device for gripping the workpiece on the spindle side is provided, and the processing proceeds with the workpiece gripped by this device Be
[0003]
Heretofore, the followings have been known as the workpiece gripping device.
[0004]
A) Radial gripping type (FIG. 9 (a)): In this type of device, a plurality of dowels (radial gripping members) 90 are disposed at equal intervals around the workpiece 30, The respective gripping claws 90 grip (clamp) the workpiece 30 in the radial direction (solid line position in the figure) and release positions (two-dot chain line position in the figure) separated from the circumferential surface of the workpiece 30 And can be switched.
[0005]
B) Axial gripping type (FIG. 9 (b)): This type of device is a backing plate (abutment) in which the rear end face (left end face in the figure) of the workpiece 30 is butted in the axial direction (left and right direction in the figure) A member 92 and a pulling claw 94 are provided. The pulling claw 94 is in pressure contact with the front end surface 30b of the work piece 30 and holds the work piece 30 in the axial direction with the backing plate 92 (solid line position in the figure) and forward from the front end face 30b of the work piece 30 It is configured to be switchable to a retreat position (two-dot chain line position in the drawing) to be retreated.
[0006]
[Problems to be solved by the invention]
In the radial direction gripping type device of A), due to the radial clamp by the holding claws 90, elastic distortion is likely to occur in the shape of the cylindrical workpiece 30. When internal grinding is performed with a grindstone 64A as shown in FIG. 1A, for example, as shown in FIG. 1A in such a distorted state, when the clamp is released after the grinding, the processed surface of the workpiece 30 by the amount of the distortion That is, the shape of the inner circumferential surface 30a is deviated from a true circle, and high processing accuracy can not be obtained.
[0007]
Therefore, in this type of device, the clamping force by the holding claws 90 must be set low in order to suppress the distortion, but if the clamping force is low, the workpiece 30 becomes easier to move, so the workpiece The cutting speed must be reduced to reduce the grinding resistance acting on 30. Therefore, there is a disadvantage that the cycle time is long and the processing efficiency is low.
[0008]
On the other hand, in the device of the axial gripping type in B), it is possible to increase the cutting speed because distortion due to the above-mentioned clamping force is unlikely to occur, but the pulling claw 94 is the front end face of the workpiece 30 during clamping. Since 30b is covered from the front, processing (end surface processing) of the front end surface 30b can not be performed. Therefore, in order to process both the circumferential surface and the inner surface of the workpiece 30 using this device, it is absolutely necessary to use it together with the device of the radial direction gripping type A), and the equipment becomes large. Moreover, the combined use of such devices requires work to transfer the workpiece between the devices at the time of transition from the peripheral surface processing step to the end surface processing step (or transition from the end surface processing step to the peripheral surface processing step). , The processing efficiency is reduced accordingly.
[0009]
In view of such circumstances, the present invention provides a workpiece holding device capable of processing both the peripheral surface and the end surface of a workpiece efficiently and with high accuracy and a processing method using the same in a compact configuration. The purpose is to
[0010]
[Means for Solving the Problems]
As means for solving the above problems, according to the present invention, there are provided a plurality of radial direction gripping members for gripping the workpiece in its radial direction, and an abutting member against which the rear end of the workpiece is axially butted. An axial gripping member is provided on the main shaft for axially clamping the workpiece with the abutment member by abutting from the front against the workpiece abutted against the abutment member, and the radial direction gripping member Radial driving means for switching between the holding position for holding the workpiece and the releasing position for releasing the work, and the radial driving means operating independently of the radial driving means, the axial holding member And an axial driving means for moving between the holding position where the axial holding member holds the workpiece in the axial direction with the contact member and the retreating position where the axial holding member holds the workpiece in the axial direction. is there.
[0011]
According to this device, by moving the axial gripping member to the gripping position, the axial gripping member and the abutting member can sufficiently clamp the workpiece without causing a large clamp distortion on the workpiece. The workpiece can be clamped in the axial direction, and the peripheral surface of the workpiece can be efficiently processed in this state. On the other hand, the end face of the workpiece can be machined without inconvenience by retracting the axial gripping member and switching the radial gripping member to the gripping position.
[0012]
Moreover, in this apparatus, since the axial gripping member and the radial gripping member are provided on the common main shaft so as to be able to operate independently of each other, the work is moved with a compact configuration. Instead, both the peripheral surface and the end surface can be processed efficiently. Specifically, the radial direction gripping member is switched from the release position to the gripping position by the operation of the radial direction driving means, and the workpiece is gripped from the radial direction by the radial direction gripping member, and in this state the end face of the workpiece After processing is performed, the axial direction gripping member is moved from the retracted position to the clamping position by the operation of the axial direction drive means, and the workpiece is axially clamped by the axial direction gripping member and the abutting member. The radial gripping member is returned to the release position by the actuation of the radial drive means, and the circumferential surface processing of the workpiece is carried out in this state, or the radial gripping by the actuation of the radial drive means
The member is switched from the release position to the grip position to center the workpiece, and the axial drive member moves the axial grip member from the stand-by position to the grip position to abut the axial grip member. After the workpiece is held in the axial direction by the member and the radial direction gripping member is returned to the release position by the operation of the radial direction driving means, the circumferential surface processing of the workpiece is performed in this state, and then the radial direction The radial gripping member is switched from the release position to the gripping position by actuation of the driving means, and the workpiece is gripped in the radial direction by the radial gripping member, and then the axial gripping member is The peripheral surface processing and the end surface processing of the workpiece can be smoothly performed by the method of returning to the retreat position and performing the end surface processing of the workpiece in this state.
[0013]
Furthermore, according to the present invention, as a specific configuration thereof, the inner shaft and the outer cylinder are disposed on the central axis of the main shaft so as to be axially movable independently of each other, and the inner shaft is axially An inner shaft driving means for moving the outer cylinder, a drive transmission mechanism for switching the radial gripping member between the holding position and the releasing position along with the axial movement of the inner shaft, and moving the outer cylinder in the axial direction Outer cylinder driving means, and a connecting member for connecting the outer cylinder and the axial gripping member so that the axial gripping member moves between the holding position and the retreating position along with the axial movement of the outer cylinder. As a result, the entire device can be made more compact by arranging both the inner shaft transmitting the radial drive force and the outer cylinder transmitting the axial drive force on the central axis of a single spindle. can do.
[0014]
In this device, when the axial gripping member is retracted to the retraction position, the axial gripping member is rotated in a direction in which the axial gripping member retracts radially outward from the front of the workpiece. It is more preferable to configure the directional drive means. Thereby, interference with the said axial direction holding member and the workpiece set from the front with respect to the said contact member becomes difficult to occur, and the carrying-in operation | work of a workpiece becomes easier. In addition, interference with the end surface processing tool is less likely to occur, and end surface processing is also facilitated.
[0015]
The specific configuration of the radial drive means and the axial drive means is not limited as long as both can operate independently (that is, they can operate independently without interlocking).
[0016]
Furthermore, according to at least one of the inner shaft driving means and the outer cylinder driving means formed by a fluid pressure cylinder, and the cylinder bore formed on the main shaft, the fluid pressure cylinder is provided further outside the main shaft. As well as being compact, the number of parts is reduced and costs are reduced.
[0017]
Furthermore, if two fluid pressure cylinders independent of each other are provided as the inner shaft drive means and the outer cylinder drive means, and these cylinder bores are formed in the main shaft, there is no need to provide the drive means outside the main shaft. Compactification and reduction of the number of parts will be further promoted.
[0018]
When two fluid pressure cylinder parts are formed on the main shaft in this way, if the formed portions are at both ends of the main shaft, machining (for example, boring) is performed than when the fluid pressure cylinder part is formed in the middle part of the main shaft And costs are further reduced.
[0019]
In this apparatus, when machining the workpiece, the radial driving means is first operated to switch the radial gripping member from the release position to the gripping position, and after the end face machining of the workpiece in this state is finished. Machining control for operating the axial drive means to move the axial gripping member from the withdrawal position to the sandwiching position and then operating the radial drive means to switch the radial gripping member from the gripping position to the release position Or when machining the workpiece, the radial drive means is first operated to switch the radial gripping member from the release position to the gripping position, and the axial drive means is actuated to carry the axial gripping member Is moved from the stand-by position to the holding position, and the radial direction drive means is operated to switch the radial direction holding member from the holding position to the release position. Circumferential surface processing of operating said radial drive means after completion of the
It is possible to provide processing control means for switching the radial gripping member from the release position to the gripping position and then operating the axial driving means to switch the axial gripping member from the gripping position to the retracted position. preferable. In this way, automation of a series of machining operations, including gripping of the workpiece, is promoted.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described based on the drawings.
[0021]
In FIG. 1 and FIG. 2, 10 is a main shaft of a machine tool, and a substantially cylindrical base member 11 is fixed to the tip of this main shaft 10, and a substrate 12 is fixed to the tip. A thin-walled diaphragm 13 is provided on the further front end side of the substrate 12, and a through hole 13 a for assisting the deformation of the diaphragm 13 is provided in the central portion thereof. A plurality of (three in the illustrated example) clamp members (radial direction grip members) 14 are fixed to the outer peripheral portion of the diaphragm 13 in the circumferential direction at equal intervals, and inward at the tip of each clamp member 14 The protruding claws 14a are formed.
[0022]
On the other hand, an inner shaft 16 and an outer cylinder 15, which are integrally rotated with the main shaft 10, are concentrically disposed at the center of the main shaft 10, and they are axially movable independently of each other. An operating member 17 is provided at the tip of the inner shaft 16, and a pusher 17a for pressing the peripheral edge of the through hole 13a of the diaphragm 13 is provided at the tip of the operating member 17 so as to project therefrom.
[0023]
In this configuration, when the pusher 17a of the operation member 17 is retracted to the position shown by the solid line in FIG. 1A and separated from the diaphragm 13, the diaphragm 13 is in a slightly deformed state and fixed to the diaphragm 13. As shown in FIGS. 1 (a) and 3 (a), the holding claws 14a are held at a holding position (holding position) for supporting the workpiece 30 from the side. On the other hand, the diaphragm 13 is deformed and fixed to the diaphragm 13 as the pusher 17a presses the center vicinity of the diaphragm 13 to the tip side as shown by the two-dot chain line in FIG. 1A. The dowel 14a is switched to the release position (open position) for releasing the workpiece 30 as shown by the two-dot chain line in FIG. 1 (a) and FIG. 3 (b).
[0024]
Therefore, a drive transmission mechanism is configured by the operation member 17 and the diaphragm 13 to switch the clamp member 14 between the holding position and the release position with the movement of the inner shaft 16.
[0025]
A nut 19 is screwed to the front end portion of the outer cylinder 15, and a donut plate-shaped operation plate 18 is disposed around the front end portion, and a central portion of the operation plate 18 corresponds to the nut 19 It is rockably engaged with a spherical surface 19a formed on the rear end face.
[0026]
The rear end of the operating shaft 20 is connected to the operating plate 18 so as to be relatively rotatable. The operation shaft 20 passes through a bush 22 and a diaphragm 13 provided on the substrate 12 and protrudes toward the tip end, and a pulling claw (axial direction gripping member) 24 is fixed to the tip end of the protrusion. As shown in FIG. 1 (b), a cam groove 20a having an inclined portion is formed on the outer peripheral surface of the operation shaft 20, while a pin 22a fitted in the cam groove 20a is fixed to the bush 22 The operating shaft 20 is rotated by a predetermined angle in conjunction with the axial movement of the operating shaft 20 by the cam mechanism composed of these components.
[0027]
A backing plate (contact member) 26 is disposed at a position immediately in front of the diaphragm 13. The backing plate 26 is supported on the side of the substrate 12 via a mounting shaft 28 passing through the diaphragm 13.
[0028]
In this configuration, when the outer cylinder 15 is pulled backward, the pull claw 24 connected to the outer cylinder 15 via the operation plate 18 and the operation shaft 20 is also integrally retracted, as shown in FIG. As shown by a solid line in FIG. 2, the workpiece 30 is held in a holding position where it is held in the front-rear direction with the backing plate 26. On the other hand, when the outer cylinder 15 advances, the pull claw 24 connected to the outer cylinder 15 via the operation plate 18 and the operation shaft 20 is also a workpiece as shown by a two-dot chain line in FIG. Retract from the holding position of 30 to the retraction position sufficiently spaced forward. Moreover, at this time, the operation shaft 20 and the pulling claw 24 are rotated and advanced by the cam action of the cam groove 20a and the pin 22a, and as a result, the angular position of the pulling claw 24 is as shown by the two-dot chain line in FIG. When setting the workpiece 30 from the front, it is switched to the retraction angle position that does not interfere with the workpiece 30.
[0029]
As means for moving the inner shaft 16 and the outer cylinder 15 individually, various drive devices conventionally known, such as one using a fluid pressure cylinder such as a hydraulic cylinder, one using a feed screw mechanism, are applied It is possible. An example of the drive mechanism is shown in FIG.
[0030]
In the figure, the front half (right half of the figure) of the spindle 10 is rotatably supported by the spindle support member 34 via a bearing 32. At a position immediately behind the spindle support member 34, a pulley 38 is fixed around the spindle 10 via a key 36, and the pulley 38 is connected to a drive source for spindle rotation via a belt (not shown). ing.
[0031]
At the rear end of the main shaft 10, a cylinder forming member 40 forming a hydraulic cylinder for driving the outer cylinder 15 and a cylinder forming member 42 forming a hydraulic cylinder for driving the inner shaft 16 are connected in series. It is fixed. At the rear end of the outer cylinder 15, a piston portion 15p having a diameter larger than that of the other portion is formed, and the piston portion 15p is fitted into the cylinder forming member 40. The rear end portion of the inner shaft 16 penetrates the rear end wall of the cylinder forming member 40 in a state of being sealed between the rear end wall, and the projecting end (rear end) has a larger diameter than other portions. The piston portion 16 p is formed, and the piston portion 16 p is inserted into the cylinder forming member 42.
[0032]
In a region between the cylinder forming members 40 and 42 and the pulley 38, a hydraulic pressure supply ring 46 is attached around the main shaft 10 via a bearing 44 so as to be relatively rotatable. A locking pin 48 is provided on the outer peripheral portion of the hydraulic pressure supply ring 46 so as to protrude, and when the locking pin 48 abuts on the base side locking member 50, the rotation of the hydraulic pressure supply ring 46 is restricted. That is, only the main shaft 10 is rotationally driven with the hydraulic pressure supply ring 46 left.
[0033]
Four circumferential grooves 51, 52, 53, 54 are axially juxtaposed on the inner circumferential surface of the hydraulic pressure supply ring 46. The circumferential groove 51 is in communication with the head side chamber (the hydraulic chamber behind the piston portion 16 p) in the cylinder forming member 42 through the oil passage 55 formed in the main shaft 10 and the cylinder forming members 40 and 42. The circumferential groove 52 is in communication with the rod side chamber (the hydraulic pressure chamber in front of the piston portion 16 p) in the cylinder forming member 42 through an oil passage 56 formed in the main shaft 10 and the cylinder forming member 40. Further, the circumferential groove 53 is in communication with the head side chamber (a hydraulic chamber behind the piston portion 15 p) in the cylinder forming member 40 through an oil passage 57 formed in the main shaft 10 and the cylinder forming member 40 The circumferential groove 54 is in communication with the rod side chamber (the hydraulic pressure chamber ahead of the piston portion 15 p) in the cylinder forming member 40 through an oil passage 58 formed in the main shaft 10.
[0034]
On the other hand, ports P1, P2, P3 and P4 connected to the circumferential grooves 51, 52, 53 and 54 are formed in the hydraulic pressure supply ring 46, and the hydraulic circuit 60 is connected to these ports P1, P2, P3 and P4. It is done. The hydraulic circuit 60 is provided with an oil pressure source, a tank, an oil pressure switching valve, etc. (not shown), and the inner shaft 15 and the outer cylinder 15 are individually operated in the front and rear direction by oil pressure supply to each port P1 to P4. It is configured. The specific relationship between the hydraulic pressure supply and the cylinder operation is as follows.
[0035]
Pressure oil is supplied from the port P1 to the head side chamber of the cylinder forming member 42 through the oil passage 55, and the pressure oil is released from the rod side chamber of the member 42 to the tank through the oil passage 56 and the port P2. → The inner shaft 16 advances.
[0036]
Pressure oil is supplied from port P2 to the rod side chamber of the cylinder forming member 42 through the oil passage 56, and pressure oil is released from the head side chamber of the member 42 to the tank through the oil passage 55 and the port P1. → The inner shaft 16 moves backward.
[0037]
The pressure oil is supplied from the port P3 to the head side chamber of the cylinder forming member 40 through the oil passage 57, and the pressure oil is released from the rod side chamber of the member 40 to the tank through the oil passage 58 and the port P4. The outer cylinder 15 advances.
[0038]
Pressure oil is supplied from the port P4 to the rod side chamber of the cylinder forming member 40 through the oil passage 58, and the pressure oil is released from the head side chamber of the member 40 to the tank through the oil passage 57 and the port P3. → The outer cylinder 15 moves backward.
[0039]
A control device 62 comprising a microcomputer or the like is electrically connected to the hydraulic pressure switching valve provided in the hydraulic circuit 60, and an electrical signal is output from the control device 62 to the hydraulic pressure switching valve. The aforementioned hydraulic pressure supply switching is performed. That is, the control device 62 constitutes processing control means for controlling the longitudinal movement of the inner shaft 16 and the outer cylinder 15 through the hydraulic circuit 60.
[0040]
In the structure shown in FIG. 4, the inner shaft 16 and the outer cylinder 15 are concentrically incorporated on the central axis of the main shaft 10, and hydraulic cylinders for operating the inner shaft 16 and the outer cylinder 15 are attached to the main shaft 10. Therefore, a very compact structure is obtained, but a more preferable structural example is shown in FIG. Here, the cylinder forming member 40 shown in FIG. 4 is omitted, and instead, a cylinder bore 10 c is recessed at the front end of the main shaft 10. The front end opening of the cylinder bore 10c is closed from the front by the base member 11, and the piston portion 15p of the rear end of the outer cylinder 15 is loaded in the bore 10c, so that the hydraulic pressure is integrated with the main shaft 10. The cylinder has been formed.
[0041]
According to this structure, since the hydraulic cylinder portion for operating the outer cylinder 15 is integrally formed on the main shaft 10, the cylinder forming member 40 shown in FIG. Will be reduced. In addition, the structure is made more compact, and the torque required to rotationally drive the spindle 10 is also reduced. This effect can be similarly obtained by forming, in the main shaft 10, the cylinder bore of the hydraulic cylinder that operates the inner shaft 16, instead of the hydraulic cylinder that operates the outer cylinder 15.
[0042]
A further preferred structural example is shown in FIG. Here, in addition to the cylinder bore 10c at the front end of the main shaft 10, a cylinder bore 10y is formed at the rear end of the main shaft 10, and the rear end opening of this cylinder bore 10y is closed from behind by the lid 43 By loading the piston portion 16p at the rear end of the inner shaft 16 therein, a hydraulic cylinder that operates the inner shaft 16 in the front-rear direction is formed.
[0043]
According to this structure, in addition to the cylinder forming member 40 shown in FIG. 4, the cylinder forming member 42 is not necessary, and the further downsizing of the structure and the reduction of the number of parts are promoted. Further, since the cylinder bores 10c and 10y are formed at the front and rear ends of the main shaft 10, the processing and the loading of the piston portions 15p and 16p are very easy.
[0044]
In either of the structures shown in FIGS. 6 and 5, an oil passage passing through each cylinder chamber may be appropriately formed on the main shaft 10 or the like.
[0045]
Next, the contents of drive control performed by the control device 62 and the operation of the entire device will be described based on the flowchart of FIG.
[0046]
0) Initial setting (step S0 in FIG. 7)
In the initial stage before setting the work piece 30 on the main spindle 10, the inner shaft 16 is advanced to press the portion near the center of the diaphragm 13 against the operation member 17 at the front end thereof, thereby deforming the diaphragm 13 The holding claw 14a of the clamp member 14 fixed to 13 is made to stand by at the release position (open position) shown in FIG. 1 (a) and the two-dot chain line and FIG. 3 (b). Further, the outer cylinder 15 is also advanced to retract the pull claw 24 connected to the outer cylinder 15 forward to a retreat position shown by a two-dot chain line in FIG.
[0047]
1) Workpiece loading (step S1)
The workpiece 30 is transported to the front of the spindle 10 by a workpiece transport device (not shown), and is abutted against the backing plate 26 from the front. At this time, each pulling claw 24 not only retreats to the front, but also the angular position of the work 30 when setting the work 30 from the front as shown by a two-dot chain line in FIG. Since the workpiece 30 is rotated to the retraction angle position that does not interfere with the movement, the loading of the workpiece 30 is extremely smoothly performed.
[0048]
2) Holding clamp (step S2)
After the workpiece 30 is carried in, the inner shaft 16 is retracted to be separated from the diaphragm 13. As a result, the diaphragm 13 is in a slightly deformed state, and the holding claws 14a of the respective clamp members 14 fixed to the diaphragm 13 are switched to the holding position shown by the solid line in FIG. That is, the workpiece 30 is gripped from the outside in the radial direction by the respective holding claws 14a. The centering of the workpiece 30 is also automatically performed by the holding clamp.
[0049]
3) Edge grinding (step S3)
The main shaft 10 is rotationally driven at a predetermined rotational speed in the holding and clamping state. As a result, the workpiece 30 is also rotationally driven about its own axis integrally with the spindle 10. In this clamping state, the front end surface 30b of the workpiece 30 is open forward over the entire circumference, so that the end surface grinding stone 64B shown in FIG. 1A is pressed against the front end surface 30b, the front end The surface 30b can be ground. Further, in this end face grinding process, since the radial distortion of the workpiece 30 by the holding clamp hardly affects the processing accuracy, the clamping force of the holding clamp can be set to a sufficiently high value.
[0050]
4) Pull clamp (step S4)
After the end face grinding process, in addition to the inner shaft 16, the outer cylinder 15 is also retracted. In conjunction with this, each pulling claw 24 retreats. Moreover, at the time of the backward movement, the operation shaft 20 and the pulling claw 24 are rotated by the cam action of the cam groove 20a and the pin 22a, and as a result, the pulling claw 24 is in the holding position holding the workpiece 30 in the front-rear direction Move (Fig. 1 (a), Fig. 2). That is, the workpiece 30 is pulled and clamped in the axial direction.
[0051]
5) Hold clamp release (step S5)
After the pulling clamp is completed, the inner shaft 16 is advanced to deform the diaphragm 13, thereby returning each dowel 14a to the initial release position. As a result, the workpiece 30 is held by the main spindle 10 only by the pull clamp.
[0052]
6) Internal grinding (step S6)
While the main spindle 10 and the workpiece 30 are rotationally driven integrally, the inner grinding stone 64A shown in FIG. 1A is pressed against the inner peripheral surface 30a of the workpiece 30 from the inside in the radial direction, The peripheral surface 30a can be ground. At this time, since the workpiece 30 is gripped only by the pulling clamp (axial clamping by the pulling claw 24 and the backing plate 26), almost no radial distortion as in the case of holding and clamping occurs, and hence the workpiece 30 Internal grinding with high accuracy.
[0053]
7) Workpiece recovery (step S7)
After the internal grinding is completed and the machined workpiece 30 is gripped by the workpiece transfer device, the pull claw 24 is retracted to the retraction position. In this state, the machined workpiece 30 can be recovered without difficulty by the workpiece transport device.
[0054]
In the method described above, the radial gripping operation by the dowel 14 a and the axial gripping operation by the pulling pawl 24 are alternately performed, and the end surface grinding process is performed during the radial gripping operation, and the inner surface grinding process is performed during the axial gripping operation. The respective grinding processes can be performed efficiently and with high precision by taking advantage of the advantages of each gripping form. Moreover, since both the radial gripping operation and the axial gripping operation are performed by the single main spindle 10, there is no need to transport the workpiece 30 at the transition from the end face grinding process to the inner surface grinding process, and only switching the holding form It is good. Therefore, the cycle time is significantly reduced as compared to the case where two types of devices are used in combination.
[0055]
This effect can be similarly obtained in the case of performing the internal grinding process first and then performing the end face grinding process. An example is shown in the flowchart of FIG.
[0056]
In the figure, the steps of initial setting (step S0) and workpiece loading (step S1) are completely the same as the method shown in FIG. After loading, the holding claw 14a is switched to the gripping position only for the purpose of centering the workpiece 30 (step S2). In this state, after switching the pulling claw 24 to the holding position (step S8), the holding claw 14a is switched to the releasing position (step S9) to set it in the pulling clamp state (axial direction holding state). Perform (step S10).
[0057]
After the internal grinding process, the holding claw 14a is switched to the holding position (step S11), and then the pulling claw 24 is released to the withdrawal position (step S12) to be in the holding clamp state (radial holding state). After the end face grinding process (step S13) is performed in this state, the workpiece 30 is recovered (step S14).
[0058]
In the method of FIG. 8, before performing the axial holding of the work piece 30 (step S8), an operation to switch the holding claw 14a to the holding position for the purpose of centering only is necessary (step S2). The method 7 is more efficient because the workpiece 30 can be machined (edge grinding) as it is after the dowel 14a is switched to the gripping position.
[0059]
Besides the above, the present invention can also take, for example, the following embodiments.
[0060]
-Although the hydraulic cylinder was used as a means to drive the holding claw 14a and the pulling claw 24 in the said embodiment, when required holding force is small, you may use a pneumatic cylinder. Alternatively, it is also possible to use an electrical means such as a servomotor.
[0061]
In the embodiment described above, the deformation of the diaphragm 13 is used to open and close the holding claws 14a. However, a collet chuck that is opened and closed by a taper action may be used as the radial direction gripping member. Alternatively, the radial direction gripping member may hold the workpiece from the inside in the radial direction (that is, press-contact with the inner circumferential surface of the workpiece).
[0062]
The shape of the workpiece 30 is not limited to the cylindrical shape as illustrated, and the present invention can be applied to the processing of workpieces of various shapes in which any circumferential surface and end surface are set as a processing surface. is there.
[0063]
【Effect of the invention】
As described above, the present invention is a device in which the radial direction gripping member and the axial direction gripping member are provided on the same main shaft so as to be able to operate independently of each other, and in this device, the radial direction gripping member The end face processing is performed while holding the workpiece, and the peripheral surface processing is performed while holding the workpiece by the axial direction gripping member. Therefore, the peripheral surface and the end surfaces of the workpiece are compacted. There is an effect that both can be processed efficiently and with high precision.
Brief Description of the Drawings
FIG. 1A is a cross-sectional side view showing an example of a workpiece gripping apparatus according to an embodiment of the present invention, and FIG. 1B shows the shape of a cam groove provided on the operation shaft of FIG. FIG.
2 is a front view of the workpiece gripping device according to FIG. 1;
3 (a) is a cross-sectional side view schematically showing a state in which the holding claws of the workpiece holding device according to FIG. 1 are in the holding position, and FIG. 3 (b) is a schematic view showing the holding claws in the released position. It is a cross-sectional side view shown to.
FIG. 4 is a cross-sectional view showing an example of a driving mechanism of a holding claw and a pulling claw in the workpiece gripping device.
FIG. 5 is a cross-sectional view showing an example in which a hydraulic cylinder for driving the pulling claws, which is a driving mechanism of the holding claws and the pulling claws in the workpiece gripping device, is integrally formed on a main shaft.
FIG. 6 is a cross-sectional view showing an example in which a driving mechanism of a holding claw and a pulling claw in the workpiece gripping device and hydraulic cylinders for driving the holding claw and the pulling claw are integrally formed on a main shaft.
FIG. 7 is a flow chart showing a control operation of a control device in the workpiece gripping device.
FIG. 8 is a flowchart showing another example of the control operation of the control device in the workpiece gripping device.
9A is a view showing an example of a conventional radial direction gripping type workpiece holding device, and FIG. 9B is a view showing an example of a conventional axial direction gripping type workpiece holding device.
[Description of the code]
10 spindles
10c, 10y cylinder bore
13 diaphragm (constitutes drive conversion mechanism)
14 Clamping member (radial gripping member)
14a Hugging
15 outer cylinder
16 inner shaft
17 Operation member (constitutes drive conversion mechanism)
18 Operation board (consisting of connecting members)
20 Operating shaft (consisting of connecting member)
24 Pull claw (axial direction gripping member)
26 backing plate (contact member)
30 works
30a inner surface of the work
30b Workpiece front end face
40, 42 cylinder forming member
60 hydraulic circuit
62 Control device (processing control means)