JP2009101496A - Machine tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a machine tool capable of increasing flexibility of workpiece machining. <P>SOLUTION: The machine tool includes: a workpiece holding means 20 for releasably holding a workpiece W1; a workpiece discharge member 30 inserted into a main spindle 12 in a manner that the workpiece discharge member 30 moves in a forward direction D2 and a backward direction D3; an elastic means 40 for biasing the workpiece discharge member 30 by elastic force in the forward direction D2; a regulatory means 50 for restraining the workpiece discharge member 30 from moving in the forward direction D2 while permitting the workpiece discharge member 30 to move in the backward direction D3 by a movement restraint part 54 configured to move in the forward direction D2 and the backward direction D3; and an actuator 60 for transmitting driving force toward the backward direction D3 to the workpiece discharge member 30 restrained from moving in the forward direction D2 by the regulatory means 50 with the movement restraint part 54 moved in the forward direction D2 and the backward direction D3. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a machine tool having a rotatable spindle.

  In a lathe that grips a workpiece with a gripping tool attached to the end of the main shaft and performs processing, a workpiece discharge shaft is inserted into the main shaft in order to discharge the processed workpiece, that is, a product. A discharge pin is attached to the tip of the workpiece discharge shaft so as to be detachable so as to correspond to workpieces of various shapes. When processing a workpiece, there is a discharge pin behind the workpiece gripped by the gripping tool. When the workpiece is processed, the product is released from the gripping of the gripping tool, and the discharge pin pushes out the product by the advancement of the workpiece discharge shaft.

  As a mechanism for moving the workpiece discharge shaft forward, there are a coil spring that urges the workpiece discharge shaft in the forward direction within the main shaft and an air cylinder that drives the workpiece discharge shaft in the forward and backward directions. When the workpiece discharge shaft is moved forward with a coil spring, the coil spring pushes the workpiece discharge shaft in the forward direction to bring the discharge pin into contact with the rear part of the workpiece. Therefore, even if there is a through hole in the workpiece longitudinal direction (main axis axis direction) Occasionally dust and cutting oil can be prevented from entering the spindle. When the workpiece discharge shaft is driven by the air cylinder, the discharge pin can be separated from the rear portion of the workpiece when the workpiece is processed, and it is possible to prevent the product after processing from being scratched.

Patent Document 1 describes a lathe that drives a knockout bar corresponding to the workpiece discharge shaft with a cylinder. The knockout bar of this lathe is connected to the operation rod via an abnormality detection piece, a compression spring, a second operation plate, and a first operation plate. Therefore, when the cylinder drives the operating rod in the forward or backward direction, the knockout bar moves in the forward or backward direction. When machining the workpiece, the nozzle of the knockout rod that moves forward by driving the cylinder is separated from the rear portion of the workpiece. In addition, since the abnormality detection sensor for detecting the displacement of the abnormality detection piece is fixed to the first operating plate, if the knockout bar is pushed too far in the backward direction, the compression spring is pushed to detect the displacement of the abnormality detection piece. .
Japanese Patent Laid-Open No. 2-100801

In a lathe that drives a workpiece discharge shaft with a cylinder, the retracted position of the workpiece discharge shaft cannot be set so that the discharge pin contacts the rear portion of the workpiece, so that a gap is generated between the discharge pin and the workpiece rear portion. Since this gap may cause dust and cutting oil to enter the spindle, such a lathe is not suitable for machining a workpiece having a through hole in the longitudinal direction.
On the other hand, in a lathe that advances the workpiece discharge shaft with a coil spring, the product is pushed out of the main shaft by the biasing force of the coil spring, so that the product that jumps out of the main shaft may hit the product receiver and cause damage. Accordingly, such a lathe is not suitable for machining a workpiece in which it is not important that there is no flaw and it is suitable for machining a workpiece in which shortening the cycle time of the workpiece machining is important.
Note that the compression spring described in Patent Document 1 is a spring for detecting the positional deviation of the abnormality detection piece, and is provided between the second operation plate interlocked with the operating rod and the abnormality detection piece, so that it is knocked out. The rod is not energized. Therefore, the gap between the discharge pin and the rear part of the workpiece is not eliminated by the compression spring, and dust and cutting oil enter the main shaft through the gap.

  The present invention has been made in view of the above problems, and an object thereof is to improve the degree of freedom of workpiece processing.

  In order to achieve the above object, the present invention provides a machine tool including a rotatable spindle, and a workpiece gripping means for releasably gripping a workpiece with a gripping tool attached to the spindle, and the workpiece on the spindle. And a work discharge member inserted into the main shaft so as to be movable in a reverse direction opposite to the forward direction, and elasticity for urging the work discharge member in the forward direction by elasticity. The movement of the workpiece discharge member in the forward direction is restricted while permitting movement of the workpiece discharge member in the backward direction at the movement restricting portion configured to move in the forward direction and the backward direction. The control means moves the movement restricting portion in the forward direction and the backward direction, and is moved in front of the workpiece discharge member whose movement in the forward direction is restricted by the restricting means. Characterized in that it comprises an actuator which transmits a driving force to the retraction direction.

  In other words, the workpiece discharge member inserted into the main shaft so as to be movable in the forward and backward directions is urged in the forward direction by the elasticity of the elastic means. Further, the movement restricting portion of the restricting means is moved in the forward direction and the backward direction by the actuator. While the workpiece discharge member is allowed to move in the backward direction, the movement restricting portion is restricted from moving in the forward direction. The workpiece discharge member, whose movement in the forward direction is restricted by the movement restriction portion, receives the driving force in the backward direction from the actuator. Therefore, when the actuator moves the movement restricting portion in the backward direction, the driving force of the actuator is transmitted to the work discharging member from the time when the movement of the workpiece discharging member in the forward direction is restricted by the movement restricting portion, and the workpiece discharging member also Move backward. Further, when the movement of the workpiece discharge member in the forward direction is not restricted by the workpiece but is restricted by the movement restriction portion, the workpiece discharge member also moves forward when the actuator moves the movement restriction portion in the forward direction.

In this machine tool, the workpiece discharge member whose movement in the forward direction is regulated by the regulating means can be brought into a position where it abuts against the workpiece. In this case, when the work is gripped by the gripping tool, the work discharging member is pushed in the backward direction. At this time, the work discharging member is released from the restriction by the restricting means, and is urged in the forward direction by the elastic means in a state of being abutted against the work. Thereby, even if there is a through hole in the longitudinal direction (main axis direction) of the workpiece, it is possible to prevent dust and cutting oil from entering the main shaft during workpiece processing.
On the other hand, when the product is discharged, the advance speed of the workpiece discharge member can be controlled by the actuator, so that the product can be prevented from jumping out of the main shaft.
From the above, it is possible to prevent dust from entering the spindle during workpiece machining, and to prevent the occurrence of scratches caused by the product jumping out of the spindle.
Of course, when the movement restricting portion is advanced by the actuator at a driving speed faster than the advance speed of the work discharge member by the elastic means, the work discharge member moves forward by the biasing force of the elastic means, and the work can be discharged quickly from the main shaft. it can.
Accordingly, it is possible to easily switch the mode in which the workpiece discharge speed is controlled by the actuator or the speed by the biasing force of the elastic means, and the degree of freedom of workpiece processing is improved.

  Even when the workpiece discharge member, whose movement in the forward direction is restricted by the restricting means, is in a position where it does not hit the work, the discharge speed of the work is set to a speed controlled by the actuator or a speed by the biasing force of the elastic means. Therefore, the degree of freedom of workpiece processing is improved.

  By the way, the movement position of the movement restricting portion that is moved by the actuator may be changeable in the forward direction and the backward direction. When the movement position of the movement restricting portion is changed in the forward direction so that the workpiece discharge member comes into contact with the workpiece, the workpiece discharge member comes into contact with the workpiece when the workpiece is held by the holding tool. On the other hand, when the movement position of the movement restricting portion is changed in the backward direction so that the workpiece discharge member does not hit the workpiece, a gap is generated between the workpiece discharge member and the workpiece when the workpiece is held by the holding tool. . As a result, it is possible to easily switch the mode in which dust and cutting oil are prevented from entering the spindle and the workpiece discharge member is prevented from being scratched by contact with the workpiece. The degree of freedom can be further improved.

  Further, the present invention is a machine tool having a rotatable spindle, and a workpiece gripping means for releasably gripping a workpiece with a gripping tool attached to the spindle, and pushing out the workpiece in the axial direction of the spindle. A workpiece discharge member that is inserted into the main shaft so as to be movable in a forward direction and a reverse direction opposite to the forward direction, and is rotatable about the rotation axis of the main shaft, and the workpiece discharge member is moved forward. A spring urging in the direction, a rod-shaped member adapted to move in the forward and backward directions, an actuator for driving the rod-shaped member in the forward and backward directions, and the rod-shaped member passed therethrough. And a connecting member that is pivotally supported by the work discharge member, and the rod-shaped member is moved so that passage of the passage portion is restricted at a position that is in the forward direction from the passage portion. Wherein the control part is provided.

  This machine tool can also control the advance speed of the workpiece discharge member with an actuator when discharging the processed product. Therefore, it is possible to prevent the product from jumping out of the main shaft. Of course, when the movement restricting portion is advanced by the actuator at a driving speed faster than the advance speed of the work discharge member by the spring, the work discharge member moves forward by the biasing force of the spring, and the work can be quickly discharged from the main shaft. Therefore, it is possible to easily switch between a mode in which the workpiece discharge speed is controlled by the actuator or a speed by the biasing force of the spring, and the degree of freedom of workpiece machining is improved.

By the way, the main spindle includes a front main spindle provided on the front main spindle, a rear main spindle provided on the rear main spindle, and the like.
The gripping tool includes various types called collets and nails.
The workpiece discharge member may be a member in which a discharge pin is detachably attached to a tip end portion of a rod-like (including a cylindrical shape) main body member, or may be a member composed of a single part.
The elastic means includes a spring or rubber having elasticity.
The actuator includes a cylinder, a motor, and the like.
The movement restricting portion may be an independent member, or may be a portion formed on a member that moves in the forward direction and the backward direction. Further, the movement restricting portion may directly restrict the movement of the workpiece discharge member in the forward direction, or indirectly in the forward direction of the workpiece discharge member via a member such as the connecting member that is different from the workpiece discharge member. May be restricted.
The rod-like member driven by the actuator includes a cylindrical member.
The passage part includes a through-hole penetrating the connecting member in the axial direction, a recessed part that is recessed from the edge of the connecting member and a rod-like member is inserted, and the like.

According to the invention which concerns on Claim 1, Claim 4, the machine tool which can improve the freedom degree of workpiece processing can be provided.
In the invention according to claim 2, it is possible to further improve the degree of freedom of workpiece machining.
In the invention according to claim 3, it is possible to provide a machine tool having a suitable configuration that improves the degree of freedom of workpiece machining.

(1) Explanation of machine tools:
FIG. 1 is a plan view schematically showing the configuration of a lathe (machine tool) 1 according to an embodiment of the present invention, and FIGS. 2, 5, 7, and 8 are plan views showing a main portion of the lathe 1 in partial cross-sectional view. 3 is an exploded plan view of the main part of the workpiece discharge member 30, FIG. 4 is a right side view for showing an example of the connecting plate, and FIG. 6 is a timing chart showing an example of the operation of the lathe. .

  As shown in FIG. 1, a lathe 1 includes a front headstock 2 having a rotatable front spindle 11, a rear spindle stock 3 having a rotatable rear spindle 12, and a front spindle (not shown) that rotationally drives the front spindle 11. Motor, a back spindle motor (not shown) that rotates the back spindle 12, a tool post 4 provided with a turret 5, a tool indexing servo motor 7 that rotates the turret 5, a loader (not shown), a control unit 80, and the like. ing. The front headstock 2 can rotate the front main shaft 11 and can drive the front main shaft 11 at least in the Z-axis direction, that is, in the axial direction of the front main shaft 11. A linear actuator 60 is fixed to the back spindle 3 that rotationally drives the back spindle 12, and the work discharge member 30 is moved in the axial direction of the back spindle 12 by this actuator. A plurality of tools such as a cutting tool 6a for front processing and a cutting tool 6b for back processing are attached to the turret 5. The loader supplies the workpiece W1 to the front spindle 11. The control unit 80 is configured by a computer system having a CPU, ROM, RAM, timer circuit, input / output circuit, and the like, and according to a program recorded in the memory, the front spindle stock 2, the rear spindle stock 3, both spindle motors, The operation of the tool post 4, the servo motor 7, the loader, etc. is controlled.

With the above configuration, first, the workpiece W1 supplied by the loader is gripped by the collet of the front spindle 11, and front machining is performed. Next, for example, the front main shaft 11 moves toward the rear main shaft 12, and the workpiece W <b> 1 is gripped by the collet 21 of the rear main shaft 12. Accordingly, the workpiece W1 gripped by the collet 21 has the front-side processed portion as the rear side and the front-side portion processed as the back side. The workpiece W1 after the back surface processing, that is, the product is discharged to the product receiver by the workpiece discharge member 30 that moves forward.
In addition to the arrangement shown in FIG. 1, various arrangements of the respective parts constituting the lathe are conceivable. The tool rest 4 is arranged on the front spindle stock 2 and the rear spindle stock 3, or the rear spindle 12 is placed above or below. The actuator 60 may be arranged on the front.

As shown in FIG. 2, the back spindle 12, the work gripping means 20, the work discharging member 30, the coil spring (elastic means) 40, the regulating means 50, the linear actuator 60, etc. are provided on the back spindle stock 3. It has been.
The back spindle 12 is rotatably attached to the back spindle 3 via a bearing 13 so that the workpiece discharge member 30 can be inserted in the axial direction D1. That is, the back main shaft 12 rotates around the workpiece discharge member 30 about the rotation axis AX1. A male screw 12a is formed on the outer peripheral surface of the rear end portion of the back main shaft 12, and a cap member 14 having a female screw is screwed into the male screw 12a. The cap member 14 engages with the rear end portion of the spring 40 and rotates together with the back main shaft 12. The back spindle 12 is rotationally driven by the back spindle motor at a timing according to the control of the control unit 80.

The workpiece gripping means 20 includes a collet (gripping tool) 21, a collet holding member 22, and collet opening / closing mechanisms 23 to 29, and grips the workpiece W <b> 1 with the collet 21 in a releasable manner.
The collet 21 is attached to the tip of the back main shaft 12 and is rotated together with the back main shaft 12. The collet 21 is formed with a tapered portion 21a that becomes thinner toward the rear side, and a slit is formed at a plurality of locations (for example, three locations) of the tapered portion. Therefore, when the taper portion 21a is tightened, the workpiece is gripped, and when the taper portion 21a is loosened, the workpiece is released.
The collet holding member 22 is attached to the front end portion of the back main shaft 12 and holds the collet 21 at the front end portion of the back main shaft 12.

  The collet opening / closing mechanism includes a collet closing member 23, a coil spring 24 for opening the collet, an extension member 25, a claw opening / closing mechanism 26, a shifter 27, a shifter lever 28, and a collet opening / closing actuator 29. The collet closing member 23 comes into contact with the tapered portion 21a of the collet and slides in the axial direction D1 of the back main shaft 12. The coil spring 24 has an end on the forward direction D2 side hooked on the collet 21, and an end on the backward direction D3 side hooked on the inner peripheral surface of the collet closing member 23, thereby moving the collet closing member 23 in the backward direction D3. Is energized. The extension member 25 contacts the rear end portion of the collet closing member 23 and slides in the axial direction D1. The claw opening / closing mechanism 26 includes a claw member 26 a that can rotate together with the back main shaft 12, and a holder 26 b that holds the claw member 26 a on the back main shaft 12. The base portion 26 a 1 of the claw member 26 a is in contact with the rear end portion of the extension member 25. The shifter 27 is formed with a tapered portion 27a that becomes thinner toward the rear side, and slides in the axial direction D1. The tapered portion 27a of the shifter is in contact with the tip portion 26a2 of the claw member 26a. The shifter lever 28 slides the shifter 27 in the axial direction D <b> 1 by driving the actuator 29. The actuator 29 is configured by, for example, a hydraulic cylinder, and generates a driving force for tightening the collet 21 according to the control of the control unit 80.

  With the above configuration, when the actuator 29 transmits the driving force for moving the shifter 27 in the backward direction D3 to the shifter lever 28, the reverse shifter 27 rotates the claw member 26a so that the claw member tip 26a2 is expanded. Then, the base 26a1 of the claw member slides the collet closing member 23 in the forward direction D2 via the extension member 25, and the collet 21 is tightened. As a result, the workpiece W1 is gripped by the collet 21. On the other hand, when the actuator 29 transmits a driving force for moving the shifter 27 in the forward direction D2 to the shifter lever 28, the collet closing member 23 and the extension member 25 are retracted by the urging force of the collet opening spring 24, and the claw member distal end portion 26a2. The claw member 26a rotates so as to narrow. As a result, the collet 21 is loosened and the workpiece W1 is released from the collet 21.

  The work discharge member 30 is inserted into the back main shaft 12 so as to be movable in the forward direction D2 and the reverse direction D3, and is rotatable about the rotation axis AX1 of the back main shaft 12. Here, the forward direction D2 is a direction in which the workpiece W1 is pushed out to the front outside of the back main shaft 12 along the axial direction D1, and the backward direction D3 is a direction opposite to the forward direction D2. The work discharge member 30 includes a substantially cylindrical work discharge shaft 32 having a through hole 32c penetrating in the axial direction D1, and a discharge pin 34 detachably attached to a tip end portion 32a of the work discharge shaft. It is set as the structure which has.

As shown in FIGS. 2 and 3, the cylindrical workpiece discharge shaft 32 has a female screw 32d formed in the vicinity of the front end portion 32a and a bearing 58 attached in the vicinity of the rear end portion 32b. A hole 32e into which a rod 91 for removing the discharge pin 34 can be inserted is formed in the work discharge shaft 32 on the rear side of the female screw 32d, and extends radially outward on the work discharge shaft 32 on the rear side of the hole 32e. The enlarged diameter portion 33 is formed.
In the discharge pin 34, a male screw 34d screwed with the female screw 32d is formed in the vicinity of the rear end portion, and a hole 34e into which a rod 92 for removing the discharge pin 34 can be inserted is formed in the front side of the male screw 34d.

The coil spring 40 is fitted in the compressed state in the axial direction D1 outside the workpiece discharge shaft 32, the rear end portion is hooked to the cap member 14, and the front end portion is hooked to the enlarged diameter portion 33 of the workpiece discharge shaft. Has been. Therefore, the spring 40 is configured such that the rear end portion is fixed with respect to the axial direction D1 while the front end portion is moved in the axial direction D1, and the work discharging member 30 is urged in the forward direction D2 by elasticity.
The work discharge member 30 described above is not fixed to the back main shaft 12. However, since the rotating force is transmitted from the spring 40 hooked on the cap member 14 that rotates together with the back main shaft 12, the work discharge member 30 rotates to some extent when the back main shaft 12 rotates. There is a difference in rotational speed between the discharge pin 34 provided on the workpiece discharge member 30 and the workpiece W1 held by the collet 21.

The restricting means 50 includes a substantially cylindrical rod-shaped member 52, a stopper member (movement restricting portion) 54, and a connecting plate (connecting member) 56, and the stopper member 54 allows the workpiece discharge member 30 to move in the backward direction D3. However, the movement of the workpiece discharge member 30 in the forward direction D2 is restricted.
The rod-shaped member 52 has a front end connected to the linear actuator 60 with its longitudinal direction extending along the rotation axis AX1 of the main axis (axial direction D1), and is driven in the forward direction D2 and the backward direction D3 by the actuator 60. . If the actuator 60 is a cylinder, the rod-shaped member 52 may be called a cylinder rod. The rear part of the rod-shaped member 52 is formed with a male screw 53 and penetrates the through hole (passage part) 57 of the connecting plate 56 in the axial direction D1. The diameter of the rear portion of the rod-shaped member 52 is slightly smaller than the diameter of the through hole 57.
The rod-shaped member 52 may not be a solid member, and may be a cylindrical member such as a substantially cylindrical shape.

The stopper member 54 is a nut in which a female screw 55 to be screwed with the male screw 53 is formed, and is attached to the rear side portion of the rod-shaped member 52 at a position in the forward direction D2 from the through hole 57. Thus, the stopper member 54 moves in the forward direction D2 and the backward direction D3 along the rotation axis AX1 of the main shaft together with the rod-like member 52 by driving the actuator 60. Further, the outer diameter of the stopper member 54 is made larger than the diameter of the through hole 57. Therefore, the stopper member 54 is a movement restricting portion where passage of the through hole 57 is restricted.
In addition, by rotating the stopper member 54 with respect to the rod-shaped member 52, the position of the stopper member 54 with respect to the rod-shaped member 52 can be adjusted in the forward direction D2 and the backward direction D3. That is, the position adjusting means constituted by the male screw 53 and the female screw 55 can change the moving position (the forward position L1 and the backward position L2, L3) of the stopper member 54 moved by the actuator 60 to the forward direction D2 and the backward direction D3. is there. Here, the movement position is a position where the stopper member 54 moves when the workpiece W1 is continuously processed, the advance position L1 is the position of the stopper member 54 at the time of discharging the product shown in FIG. 5, and the retreat positions L2 and L3 are shown in FIG. It is set as the position of the stopper member 54 at the time of the workpiece | work processing shown to 2 and 7.

As shown in FIGS. 2 and 4A, the connecting plate (connecting member) 56 has a through hole 57 through which the rear side portion of the rod-like member 52 is passed, and is connected to the work discharge member 30 via a bearing 58. It is pivotally supported. That is, the connecting plate 56 is provided so as to be rotatable with respect to the work discharge shaft 32 and is not moved in the axial direction D1 with respect to the work discharge shaft 32. Thereby, the connecting plate 56 moves in the axial direction D1 together with the workpiece discharge shaft 32.
In addition, the passage site | part of the connection member which lets the rod-shaped member 52 pass is not limited to a through-hole. For example, as shown in FIG. 4B, a recess 157 that is recessed from the left edge of the connecting member 156 and into which a rod-shaped member 52 is inserted may be used. In this case, the work of combining the connecting member 156 and the rod-shaped member 52 is facilitated, and there is an advantage that it is easy to absorb the variation in the position of the rod-shaped member 52 with respect to the workpiece discharge shaft 32.
Of course, the shape of the connecting member is not limited to the shape shown in FIG. 4, and is not limited to the plate shape.

  The regulating means 50 having the above configuration regulates the movement of the workpiece discharge member 30 in the forward direction D2 by regulating the movement of the connecting plate 56 in the forward direction D2 by the stopper member 54. On the other hand, even if the stopper member 54 is in a position where the movement of the connecting plate 56 and the workpiece discharge member 30 in the forward direction D2 is restricted, the regulating means 50 moves the connecting plate 56 and the workpiece discharge member 30 in the backward direction D3. Allow.

  The linear actuator 60 is attached to the back spindle stock 3 along with the back spindle 12 by causing the rod-shaped member 52 to protrude in the backward direction D3. The actuator 60 is an actuator capable of operating speed control, such as an air cylinder or a servo motor, and drives the rod-shaped member 52 in the forward direction D2 and the backward direction D3 according to the control of the control unit 80. The actuator 60 can adjust the driving speed of the rod-shaped member 52. Thereby, the actuator 60 moves the movement restricting portion 54 in the forward direction D2 and the backward direction D3 along the rotation axis AX1 of the main shaft at the set driving speed. Further, when the stopper member 54 and the connecting plate 56 are in contact with each other, that is, when the movement of the work discharge member 30 in the forward direction D2 is restricted by the restricting means 50, the actuator 60 moves relative to the work discharge member 30. Thus, the driving force in the backward direction D3 is transmitted.

  In addition to the above, the blow head air supply mechanism 15 for supplying the back spindle 12 with compressed air for preventing the cutting spindle and oil from entering the back spindle 12 from the sliding of the collet 21. Also, a sealing air supply mechanism 16 for supplying pressurized air for preventing the oil in the bearing 13 portion from entering the main shaft is provided.

Under the control of the control unit 80, the main lathe 1 continuously processes the workpiece W1 on the back according to the timing chart shown in FIG.
When the collet 21 is opened and the stopper member 54 is in the retracted position L2 shown in FIG. 2 or the retracted position L3 shown in FIG. 7, the workpiece W1 after front processing is supplied to the collet 21 by the control of the control unit 80. (Timing t1-t2). At this timing, for example, the front main shaft 11 moves toward the rear main shaft 12.

At subsequent timing t3, the collet opening / closing actuator 29 moves the shifter 27 in the backward direction D3. As a result, the collet 21 is closed and the workpiece W1 is gripped by the collet 21. Then, the workpiece W1 is released from the collet of the front main spindle 11.
At subsequent timings t4 to t5, the back surface processing of the workpiece W1 is performed under the control of the control unit 80. At this timing, for example, the turret 5 is driven so that the tool post 4 contacts the work W1 with the tool post 4 and the back spindle stock 3 drives the back spindle 12 in the axial direction D1.
At the subsequent timing t6, the collet opening / closing actuator 29 moves the shifter 27 in the forward direction D2. Thereby, the collet 21 is opened, and the workpiece W1 after processing is released.

At subsequent timings t7 to t8, the stopper member 54 is moved from the retreat positions L2 and L3 to the advance position L1 shown in FIG. 5 at the drive speed set by the actuator 60. At this time, the stopper member 54 that restricts the advancement of the connecting plate 56 moves forward, and the work discharge member 30 that pivotally supports the connecting plate 56 is biased in the forward direction D2 by the coil spring 40. The discharge member 30 moves forward, and the discharge pin 34 pushes the work W1. Accordingly, the processed workpiece W1 is pushed out from the back spindle 12 in the forward direction D2 and discharged to a product receiver (not shown).
At subsequent timings t9 to t10, the stopper member 54 is moved from the forward movement position L1 to the backward movement positions L2 and L3 shown in FIGS. 2 and 7 at the drive speed set by the actuator 60. When the retreating stopper member 54 is in contact with the connecting plate 56, the driving force from the actuator 60 is transmitted to the work discharging member 30 via the connecting plate 56, and the work discharging member 30 resists the biasing force of the spring 40. And retreat.

Thereafter, the next workpiece W1 is processed on the back surface at timings t1 to t10.
By repeating the operation according to the above timings t1 to t10, the workpiece W1 is continuously machined on the back surface.

  When changing the type of workpiece to be processed, it is necessary to replace the discharge pin in accordance with the workpiece to be processed. FIG. 8 shows a state where the discharge pin 34 is removed from the work discharge shaft 32. When the discharge pin 34 is replaced, the stopper member 54 is moved in the forward direction D2 on the male screw 53 of the rod-shaped member, and the collet holding member 22, the collet 21, the collet closing member 23, and the spring 24 are removed from the back main shaft 12. The stopper member 54 is advanced by the actuator 60. At this time, the work discharge member 30 advances by the biasing force of the spring 40, and the hole 34e of the discharge pin and the hole 32e of the work discharge shaft are brought out of the back main shaft 12. When the rods 91 and 92 are inserted into the holes 32e and 34e and the discharge pin 34 is rotated with respect to the workpiece discharge shaft 32, the discharge pin 34 can be attached and detached. Of course, after the discharge pin 34 is attached to the work discharge shaft 32, the stopper member 54 is retracted by the actuator 60, and the spring 24, the collet closing member 23, the collet 21 and the collet holding member 22 are mounted on the back main shaft 12, Accordingly, the stopper member 54 may be moved in the backward direction D3 on the male screw 53 of the rod-shaped member.

(2) Actions and effects of machine tools:
Next, functions and effects of the machine tool according to the present embodiment will be described.
2, when the work W1 is separated from the discharge pin 34 and the back surface processing is performed, the position of the stopper member 54 with respect to the rear portion of the rod-shaped member 52 is adjusted, and the discharge is performed when the stopper member 54 is in the retracted position L2. The pin 34 is kept slightly away from the workpiece W1 (gap C1). If the drive range of the actuator 60 can be set, the retreat position of the drive range may be set so that the discharge pin 34 is separated from the workpiece W1.
When the workpiece is continuously machined according to the timing chart shown in FIG. 6, a gap C1 is generated between the discharge pin 34 and the workpiece W1 when the workpiece W1 is gripped at timings t1 to t3. When back processing is performed at timings t4 to t5, a difference occurs between the rotation speed of the workpiece W1 and the rotation speed of the discharge pin 34. However, the rear portion of the workpiece W1 is not rubbed by the discharge pin 34, so the processed product is scratched. Can be prevented from occurring.

Further, when discharging the processed product at timings t7 to t8, if the setting of the advance speed of the actuator 60 is set slower than the moving speed of the work discharge member 30 that moves forward by the biasing force of the coil spring 40, the work discharge is performed. The advance speed of the member 30 is regulated by the advance speed of the stopper member 54. Thereby, the advance speed of the discharge pin 34 is controlled by the actuator 60, and the product can be prevented from jumping out from the back main shaft 12. Therefore, the occurrence of scratches caused by the product hitting the product receiving force is suppressed.
Of course, when continuously processing a workpiece in which it is important to shorten the cycle time of the workpiece processing, the advance speed of the actuator 60 is set faster than the moving speed of the workpiece discharge member 30 that moves forward by the biasing force of the spring 40. And it is sufficient. Then, the workpiece discharge member 30 moves forward by the biasing force of the spring 40, and the product is quickly pushed out by the discharge pin 34.

On the other hand, as shown in FIG. 7, when the back surface is processed by bringing the workpiece W1 into contact with the discharge pin 34, the position of the stopper member 54 with respect to the rear portion of the rod-shaped member 52 is adjusted, and the stopper member 54 is in the retracted position L3. Sometimes the discharge pin 34 is in contact with the workpiece W1. If the drive range of the actuator 60 can be set, the retracted position of the drive range may be set so that the workpiece W1 and the discharge pin 34 are in contact with each other.
When the workpiece is continuously machined according to the timing chart shown in FIG. 6, the discharge pin 34 is slightly pushed by the workpiece W1 when the workpiece W1 is gripped at timings t1 to t3. At this time, the connecting plate 56 pivotally supported by the workpiece discharge member 30 is slightly retracted, and a gap C <b> 2 is generated between the stopper member 54 and the connecting plate 56. That is, the work discharge member 30 is released from the restriction by the restriction means 50, and is urged in the forward direction D2 by the spring 40 in a state where it abuts against the work W1. Accordingly, when back machining is performed at timings t4 to t5, it is possible to prevent dust and cutting oil from entering the back spindle 12 even if there are through holes in the longitudinal direction of the workpiece.
Of course, when the processed product is discharged at timings t7 to t8, the forward speed of the discharge pin 34 is set to a speed controlled by the actuator 60 by the setting of the forward speed of the actuator 60, or the speed by the biasing force of the spring 40 is set. It can be done.

  If the workpiece discharge shaft is advanced only by a coil spring as in a conventional lathe, the workpiece may be damaged. Moreover, when the workpiece discharge shaft is driven only by the cylinder, the workpiece is less likely to be damaged, but dust or the like may enter the spindle during workpiece processing. Even if the lathe is configured so that the work discharge shaft is moved backward by the coil spring and the work discharge shaft is advanced by the cylinder, the advance position of the work discharge shaft is controlled by the cylinder so that the discharge pin contacts the rear part of the work. Since this is not easy, a gap is generated between the discharge pin and the rear part of the workpiece. Accordingly, even in the lathe, dust or the like may enter the spindle during workpiece machining.

The lathe according to the present embodiment adjusts the position of the stopper member 54 with respect to the rear portion of the rod-shaped member 52, thereby bringing the discharge pin 34 into contact with the workpiece W1 or separating the discharge pin 34 from the workpiece W1 during workpiece processing. The mode to perform can be easily switched. For example, when processing a workpiece in which it is important that there is no scratch, the discharge pin is processed away from the workpiece, and the advance speed of the discharge pin is set to a speed controlled by the actuator. Thereby, it is possible to prevent the product from being scratched. On the other hand, when processing a workpiece having a through hole in the workpiece longitudinal direction, the workpiece may be processed by bringing a discharge pin into contact with the workpiece. As a result, it is possible to prevent dust and the like from entering the spindle during workpiece machining.
Further, by adjusting the driving speed of the actuator 60, it is possible to easily switch the mode in which the discharge speed of the workpiece is set to a speed controlled by the actuator or to the speed by the biasing force of the elastic means.

Further, as shown in FIG. 8, by removing the collet holding member 22, the collet 21, the collet closing member 23, and the spring 24 from the back main shaft 12, the hole 34e of the discharge pin and the hole 32e of the work discharge shaft are formed from the back main shaft 12. Is issued. Therefore, it is possible to easily perform the operation of inserting the rods 91 and 92 into the holes 32e and 34e and attaching and removing the discharge pin 34 to and from the workpiece discharge shaft 32.
In the conventional lathe that drives the workpiece discharge shaft only with the cylinder, the position of the workpiece discharge shaft in the axial direction with respect to the cylinder rod cannot be changed, so that the discharge pin cannot be sufficiently taken out from the main shaft. Therefore, in such a conventional lathe, it is not easy to replace the discharge pin.

  As described above, according to the present invention, it is possible to provide a machine tool capable of improving the degree of freedom of workpiece machining. Further, since the stopper member 54 can be adjusted in the forward direction and the backward direction with respect to the rear portion of the rod-like member 52, it becomes possible to process workpieces of various lengths, and exchange the tip portion of the workpiece discharge member. Becomes easy.

(3) Modification:
By the way, this invention is applicable also to the lathe etc. of the part which performs front processing.
The workpiece discharge member for discharging the workpiece may be a rod-shaped member (including a cylindrical shape) made of a single component.
The elastic means for urging the workpiece discharge member in the forward direction may be rubber.
The movement restricting portion that restricts the movement of the workpiece discharge member in the forward direction may not be an independent member such as a portion formed in the rod-like member with a large diameter.

  Note that the present invention is not limited to the above-described embodiments and modifications, but the configurations disclosed in the above-described embodiments and modifications are mutually replaced, the combinations are changed, known techniques, and the above-described configurations. Configurations in which the respective configurations disclosed in the embodiments and modifications are mutually replaced or combinations thereof are also included.

The top view which shows the outline of a structure of a lathe. The top view which shows the principal part of the lathe of the state which hold | gripped the workpiece | work in partial cross section. The principal part top view which decomposes | disassembles and shows the front-end | tip part of a workpiece | work discharge member. The right view which shows the principal part of the lathe of the part in which the connection board was provided. The top view which shows the principal part of the lathe when discharging the product after a process in partial cross section. The timing chart which shows an example of operation | movement of a lathe. The top view which shows the principal part of the lathe of the state which made the discharge pin contact and hold | gripped the workpiece | work in partial cross section. The top view which shows a mode that a discharge pin is removed from a workpiece | work discharge axis | shaft, and a partial cross section is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Lathe (machine tool), 2 ... Front spindle stock, 3 ... Back spindle stock, 4 ... Turret,
11 ... Front spindle, 12 ... Back spindle, 14 ... Cap member,
20: Work gripping means,
21 ... Collet (gripping tool), 22 ... Collet holding member, 23 ... Collet closing member,
24 ... Collet opening spring, 25 ... Extension member, 26 ... Claw opening / closing mechanism,
27 ... Shifter, 28 ... Shifter lever, 29 ... Collet opening / closing actuator,
30 ... Work discharge member, 32 ... Work discharge shaft, 33 ... Expanded diameter part, 34 ... Discharge pin,
40: Spring (elastic means),
50 ... regulatory means,
52 ... Rod-shaped member, 53 ... Male screw (part of the position adjusting means),
54 ... Stopper member (movement restriction part), 55 ... Female screw (a part of position adjusting means),
56, 156 ... connecting plate (connecting member), 57 ... through hole (passing part), 58 ... bearing,
60 ... Linear actuator,
80 ... control unit,
AX1 ... rotating shaft, D1 ... axial direction, D2 ... forward direction, D3 ... reverse direction,
L1, L2, L3 ... movement position, W1 ... work,

Claims (4)

A machine tool with a rotatable spindle,
A workpiece gripping means for releasably gripping the workpiece with a gripping tool attached to the spindle;
A work discharge member inserted into the main shaft so as to be movable in a forward direction in which the work is pushed out in the axial direction of the main shaft and in a reverse direction opposite to the forward direction;
Elastic means for urging the workpiece discharge member in the forward direction by elasticity;
Restriction means for restricting movement of the workpiece discharge member in the forward direction while permitting movement of the workpiece discharge member in the backward direction at a movement restriction portion adapted to move in the forward direction and the reverse direction; ,
An actuator that moves the movement restricting portion in the forward direction and the backward direction, and that transmits a driving force in the backward direction to the workpiece discharge member whose movement in the forward direction is restricted by the restricting means. A machine tool characterized by that.   The machine tool according to claim 1, wherein the restricting unit includes a position adjusting unit that can change a movement position of the movement restricting portion moved by the actuator in the forward direction and the backward direction. The restricting means includes a rod-shaped member that is driven in the forward direction and the backward direction by the actuator, and a connecting member that has a passage portion through which the rod-shaped member has passed and is pivotally supported by the work discharge member,
The movement restricting portion is a stopper member that is attached to the rod-shaped member at a position that is in the forward direction from the passage portion, and that is restricted from passing through the passage portion,
The position adjusting means is a means in which a male screw formed on the rod-shaped member and a female screw formed on the stopper member are screwed together to adjust the movement position of the stopper member;
The machine tool according to claim 2, wherein the actuator transmits a driving force in the backward direction to the workpiece discharge member when the stopper member and the connecting member are in contact with each other. A machine tool with a rotatable spindle,
A workpiece gripping means for releasably gripping the workpiece with a gripping tool attached to the spindle;
Workpiece discharge that is inserted into the main shaft so as to be movable in a forward direction in which the work is pushed in the axial direction of the main shaft and in a reverse direction opposite to the forward direction, and is rotatable about the rotation axis of the main shaft Members,
A spring for biasing the workpiece discharge member in the forward direction;
A rod-shaped member adapted to move in the forward direction and the backward direction;
An actuator for driving the rod-shaped member in the forward direction and the backward direction;
A connecting member that has a passage portion through which the rod-shaped member has passed and is pivotally supported by the work discharge member;
A machine tool, wherein the bar-like member is provided with a movement restricting portion where passage of the passing portion is restricted at a position in the forward direction from the passing portion.

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