Working machinery

Abstract

To provide a machine tool equipped with a workpiece guide at the center of the spindle chuck. [Solution] A machine tool comprising: a work spindle device equipped with a spindle chuck for rotatably gripping a workpiece; a turret device having a plurality of tools mounted on a swivelable tool post for machining by moving the tools on a workpiece gripped by the work spindle device; and a control device for controlling the drive of the work spindle device and the turret device, wherein the work spindle device is mounted to the axial center of the spindle chuck so as to be able to move back and forth and is equipped with a work guide that is inserted into the inner diameter of the workpiece in an advanced position pushed out by fluid pressure; and the turret device is mounted on the tool post and is equipped with a pusher that pushes the work guide to a retracted position and presses the workpiece against the seating surface of the spindle chuck.

Description

Technical Field

[0001] The present invention relates to a machine tool provided with a work guide at the center of a spindle chuck.

Background Art

[0002] Some spindle devices for gripping a work are provided with a work guide that holds the work at a central position in order to grip the work with the spindle chuck. For example, Patent Document 1 listed below discloses a centering mechanism for a machine tool. An inner diameter centering unit is provided at the center of the spindle chuck, and after a machined work is discharged, a centering cylinder extends to advance to a centering position against a spring force. The centering position of the inner diameter centering unit is confirmed by a proximity switch. Then, the work W is manually inserted into the inner diameter centering unit of the spindle chuck. Thereafter, by the output of a supporting cylinder, a plunger that advances against the spring force pushes centering pins outward in the radial direction, so that the inner peripheral surface of the work is supported and centering is completed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the aforementioned conventional example, the internal diameter centering unit is advanced by a centering cylinder, and a plunger pushes out a centering pin by a support cylinder to support the workpiece. Such workpiece centering mechanisms increase the number of parts in the spindle unit and also increase the size of the spindle unit itself due to the incorporation of cylinders. Furthermore, combining a cylinder that outputs axial movement to a rotating spindle chuck complicates the structure of the spindle unit. Therefore, there is a need for a machine tool that simplifies the configuration of the spindle unit while still having a workpiece guide at the center of the spindle chuck.

[0005] Therefore, the present invention aims to provide a machine tool equipped with a work guide at the center of the spindle chuck in order to solve these problems. [Means for solving the problem]

[0006] The present invention comprises a work spindle device equipped with a spindle chuck for rotatably gripping a workpiece, a turret device having a plurality of tools mounted on a swivelable tool post for machining by moving the tools on a workpiece gripped by the work spindle device, and a control device for controlling the drive of the work spindle device and the turret device, wherein the work spindle device is mounted to the axial portion of the spindle chuck so as to be able to move back and forth and is equipped with a work guide that is inserted into the inner diameter portion of the workpiece in an advanced position pushed out by fluid pressure, and the turret device is mounted on the tool post and is equipped with a pusher that pushes the work guide to a retracted position and presses the workpiece against the seating surface of the spindle chuck. [Effects of the Invention]

[0007] According to the above configuration, the drive control in the control device causes the workpiece held in the spindle chuck of the workpiece spindle device to rotate, and the tool mounted on the tool post of the turret device, which is indexed by rotation, moves to perform predetermined workpiece machining. At this time, a workpiece guide is mounted on the axis of the spindle chuck of the workpiece spindle device so as to be able to move back and forth, and the inner diameter of the workpiece is fitted into the workpiece guide, which is pushed out in the forward position by fluid pressure. Then, a pusher mounted on the tool post of the turret device pushes the workpiece guide holding the workpiece to the retracted position, and the workpiece is pressed against the seating surface of the spindle chuck. After that, the workpiece is held in the spindle chuck, and turning or other machining of the inner diameter is performed on the tool on the tool post. [Brief explanation of the drawing]

[0008] [Figure 1] This is a perspective view showing the internal structure of one embodiment of a machine tool. [Figure 2] This is a cross-sectional view showing the internal structure of the first workpiece spindle device. [Figure 3] This is a partial cross-sectional view of a spindle chuck equipped with a work guide. [Figure 4] This is a cross-sectional view showing a part of the spindle chuck and the pusher, which is a means of pushing back. [Figure 5] This is a cross-sectional view showing the situation in which a pusher acts on a work guide. [Figure 6] This diagram shows the internal diameter machining process on a workpiece. [Modes for carrying out the invention]

[0009] An embodiment of the machine tool according to the present invention will be described below with reference to the drawings. Figure 1 is a perspective view showing the internal structure of an embodiment of the machine tool. The machine tool 1 of this embodiment is an NC lathe, and various processing devices for machining a workpiece are assembled on the bed 6. The machine tool 1 is a two-spindle turret lathe with opposing axes, mounted on a slant-type bed that is inclined so that the front side is lower. As processing devices for machining a workpiece, a first workpiece spindle device 3 that rotatably grips the workpiece, a second workpiece spindle device 4 arranged opposite to the first workpiece spindle device 3, and a turret device 5 having a plurality of tools are provided, and their drive control is performed by a control device.

[0010] The first workpiece spindle unit 3 is designed so that the centerline of the spindle is in the machine width direction and horizontal, and the second workpiece spindle unit 4 has its spindles arranged coaxially with those of the first workpiece spindle unit 3. In this embodiment, the direction parallel to the spindle of the first workpiece spindle unit 3 (the width direction of the bed 6) will be described as the Z-axis. In the first workpiece spindle unit 3, the headstock 11 is integrated with the base 13, and the base 13 is fixed to the bed 6 by bolts. A spindle is rotatably mounted on the cylindrical headstock 11, and a spindle chuck 12 for gripping and releasing workpieces is attached thereto. The second workpiece spindle unit 4 is similar to the first workpiece spindle unit 3 in that a spindle chuck 16 is provided on a rotatable spindle on the headstock 15, but it is able to move in the Z-axis direction by a spindle slide 14.

[0011] The turret device 5 is configured such that multiple tools T are mounted at equal intervals in the circumferential direction on a disc-shaped tool post 18, and the tool T to be used for machining can be selected by swivel indexing. The tool post 18 is mounted on a turret Z-axis slide 19 and is located behind the second work spindle device 4. The tool post 18 can move in the Z-axis direction parallel to the spindle, in the X-axis direction with a forward tilt of 45 degrees, the same as the inclination of the bed 6, and in the vertical Y-axis direction. The turret device 5 and the second work spindle device 4 are equipped with a sliding structure that slides along guide rails in each axial direction, and a ball screw mechanism that converts the rotation of a servo motor into linear motion.

[0012] Figure 2 is a cross-sectional view showing the internal structure of the first workpiece spindle unit 3. This first workpiece spindle unit 3 performs internal diameter machining on a ring-shaped workpiece W, and a workpiece guide 21 is provided at the center of the spindle chuck 12. The first workpiece spindle unit 3 has a spindle 22 rotatably mounted inside a cylindrical headstock 11, with the spindle chuck 12 fixed to one end of the spindle 22, and a rotary hydraulic cylinder (chuck cylinder) 23 provided on the opposite side. A pulley 24 is fixed to the spindle 22, and a timing belt is stretched between it and the pulley on the servo motor side.

[0013] The chuck cylinder 23 is a double-rod type hydraulic cylinder, configured to receive hydraulic pressure via a built-in inducer. The spindle chuck 12 is connected to the piston rod of the chuck cylinder 23 via a drawbar 26, and the chuck jaws 27 are opened and closed by hydraulic pressure. In the first workpiece spindle device 3, the piston rod of the chuck cylinder 23 and the drawbar 26 are cylindrical, and a central hole is formed in the piston, making the center of rotation hollow. Pipes 28 and 29 for passing fluid are inserted into this hollow section in a double structure.

[0014] Coolant acting on the work guide 21 is supplied to the inner pipe 28 via an inducer 31, and air for seating determination is supplied to the outer pipe 29 via an inducer 32. The machine tool 1 is equipped with a coolant system for handling coolant used for cleaning chips generated during work processing and cooling the processed area. The coolant system has a coolant tank (not shown) located below the processing chamber where work processing takes place, and the coolant stored there is used repeatedly. A coolant pump equipped with a strainer is installed in the coolant tank, and coolant can be supplied to various locations via coolant pipes.

[0015] The spindle chuck 12 is a retractable pin arbor chuck, with three chuck jaws 27 arranged on the same circumference, each attached to the tip of a pin arbor 35. The pin arbor 35 is assembled to the main body block 36 so as to slide at a predetermined inclination angle with respect to the center line O, and is configured to transmit the output of the chuck cylinder 23 through a connecting structure with the drawbar 26. The spindle chuck 12 is designed so that when the three pin arbors 35 are retracted to the left side of the drawing, each chuck jaw 27 moves simultaneously to grip the workpiece W towards the center line O. At that time, it is necessary to maintain the workpiece W in a fixed position until the chuck jaws 27 grip it, and for this purpose, the spindle chuck 12 is provided with a workpiece guide 21.

[0016] Figure 3 is a partial cross-sectional view of a spindle chuck 12 equipped with a workpiece guide 21. The spindle chuck 12 consists of two central blocks 37 and 38, which are joined together by bolts (not shown), with the central block 38 being bolted to the main body block 36. A cylinder portion 39 is formed in the central blocks 37 and 38, into which the piston portion 212 side of the workpiece guide 21 is inserted. The workpiece guide 21 has an enlarged piston portion 212 formed at one end of a cylindrical sliding portion 211.

[0017] The cylinder portion 39 is formed in the combined portion of the two central blocks 37 and 38, and the central block 37 has a sliding support portion 371 that penetrates from the cylinder portion 39 towards the seating surface 372. In addition, a protruding seating portion 373 is formed on the seating surface 372 of the central block 37, forming an outlet for the air supplied to the pipe 29. The work guide 21 is inserted so that the sliding portion 211 penetrates the sliding support portion 371, and is displaced by axial movement along the center line O to a forward position where the tip protrudes beyond the seating portion 373 and a backward position where it is retracted toward the sliding support portion 371 side of the seating portion 373.

[0018] A connection pipe for supplying the coolant fed into the pipe and the air fed into the aforementioned pipe to the spindle chuck is fitted into the central block. In the connection pipe, a coolant flow path is formed at a position overlapping the center line, and an air flow path is formed at a position deviated from the center line. In the connection pipe, the coolant flow path communicates with the cylinder portion, and the coolant is fed therein as indicated by the outlined arrow. The work guide is movable from the retracted position to the advanced position as the piston portion is pushed by the pressure of the supplied coolant.

[0019] The spindle chuck is provided with a positioning mechanism so that the work guide can be positioned at the advanced position and the retracted position. In this positioning mechanism, V-shaped annular grooves are formed in the sliding portion of the work guide, and a positioning plunger is incorporated in the central block. The positioning plunger is a ball plunger with a tip ball biased by a spring, and is mounted such that the ball is located inside the sliding support portion. The position where the ball of the positioning plunger fits into the annular groove is the advanced position of the work guide, and the position where the ball fits into the annular groove is the retracted position of the work guide.

[0020] In the spindle chuck, the work guide is movable to the advanced position by the pressure of the coolant, but is not provided with power for returning to the retracted position. Therefore, in the present embodiment, a turret device is used as means for pushing the work guide back to the retracted position. Figure 4 is a cross-sectional view showing a part of the spindle chuck and a pusher serving as the push-back means. In the turret device, a plurality of tools are mounted on the tool post, and in addition to the tools, a pusher for pressing the work against the seating portion is also mounted. Conventionally, the configuration was adapted only for the work, but the present embodiment has a configuration that can also cope with pushing back the work guide.

[0021] In the pusher 51, a support rod 54 is inserted into a base block 53 fixed to the tool post 18 side, and the pusher 51 is configured to be displaceable along a center line O1 parallel to the Z axis within the base block 53. The support rod 54 has a flange portion 541 formed at an intermediate portion thereof, and a biasing force from a coil spring 55 acts toward the opposing spindle chuck 12 side. The support rod 54 protruding from the base block 53 has a guide contact member 56 for pushing the work guide 21 to the retracted position and a work contact member 57 for pressing the work W against the seating portion 373 attached to its tip portion.

[0022] The guide contact member 56 and the work contact member 57 are configured to be replaceable according to the dimensions of the work W and the work guide 21. The guide contact member 56 has a cylindrical shape extending the tip of the support rod 54, and the work contact member 57 has a donut shape that widens the tip portion of the support rod 54 in the radial direction. Both the sliding portion 211 of the cylindrical work guide 21 and the guide contact member 56 are formed to match the inner diameter dimension of the work W. Such a pusher 51 is positioned such that its center line O1 and the center line O of the spindle chuck 12 are aligned on a straight line by the swiveling indexing of the tool post 18 and the movement of the turret device 5 in each axial direction relative to the tool post 18.

[0023] Next, the inner diameter machining of the work W performed by the first work spindle device 3 will be described. Here, Fig. 5 is a cross-sectional view showing a state where the pusher acts on the work guide, and Fig. 6 is a diagram showing a state of inner diameter machining on the work. Figs. 3 to 6 show stepwise the processes from the mounting of the work W to the spindle chuck 12 to the inner diameter machining. First, in order to machine the work W with the work spindle device 3, an operator manually mounts the work W to the spindle chuck 12. At that time, in the work spindle device 3, as shown in Fig. 3, the work guide 21 is pushed forward (to the right side in the drawing) by the pressure of the coolant fed into the cylinder portion 39.

[0024] The work guide 21 moves forward, and the ball of the positioning plunger 42 engages with the annular groove 215, stopping its pressurized movement under coolant. This stopping position relative to the annular groove 215 is the forward position of the work guide 21, and the tip of the work guide 21 protrudes beyond the seating portion 373 of the seating surface 372. Therefore, the operator can hold the workpiece W in the spindle chuck 12 as shown in Figure 4 by fitting the central hole (inner diameter portion) of the workpiece W into the work guide 21.

[0025] Next, before the workpiece W is gripped by the spindle chuck 12, the workpiece W is positioned by the pusher 51. Therefore, in the turret device 5, the pusher 51 attached to the tool post 18 is pivoted and indexed, and the pusher 51 moves to the position shown in Figure 4 by moving in each axial direction. Then, with the center line O1 of the pusher 51 aligned with the center line O of the spindle chuck 12, it moves further, and the guide contact member 56 abuts against the workpiece guide 21 as shown in Figure 5.

[0026] Subsequently, as the guide contact member 56 enters the inner diameter portion of the workpiece W, the workpiece guide 21 is pushed back and pushed out from the inner diameter portion of the workpiece W. At that time, the workpiece contact member 57 is pressed against the end face of the workpiece W, and the coil spring 55 is compressed by the reaction force. The workpiece contact member 57 presses the workpiece W against the seating portion 373 due to the spring force of the coil spring 55. At the same time, the ball of the positioning plunger 42 fits into the annular groove 216 of the workpiece guide 21, and the workpiece guide 21 is positioned in the retracted position.

[0027] Then, the spindle chuck 12 grips the workpiece W with the chuck jaws 27 as the pin arbor 35 is retracted, and the turret device 5 moves away from the workpiece W as the pusher 51 retracts in the opposite direction as indicated by the arrow in Figure 5. In the turret device 5, the corresponding tool T is indexed by swivel indexing, and turning is performed on the inner diameter of the workpiece W, as shown in Figure 6. In the machine tool 1, after the first machining is performed by the first workpiece spindle device 3, the workpiece W is transferred to the second workpiece spindle device 4 for the second machining. In the second workpiece spindle device 4, the spindle slide 14 moves to receive the workpiece W from the first workpiece spindle device 3 by the spindle chuck 16 and returns to its fixed position, the turret device 5 performs swivel indexing of the corresponding tool T, and the predetermined machining is performed on the workpiece W by the second workpiece spindle device 4.

[0028] Therefore, in this embodiment, the work guide 21 provided on the spindle chuck 12 is moved to the forward position by the pressure of the coolant and pushed back to the retracted position by the pusher 51 provided on the turret device 5. As a result, the first work spindle device 3 does not need to have a cylinder for the work guide as in the conventional design, and its configuration can be simplified and miniaturized. Furthermore, since the machine tool 1 utilizes the coolant device and turret device 5 that have been conventionally provided in turret lathes to move the work guide 21 forward and backward, the cost associated with the improvements can be kept down. In addition, in this embodiment, since coolant is used as the fluid to move the work guide 21 to the forward position, a highly airtight seal structure is not required in the cylinder section 39.

[0029] Although one embodiment of the present invention has been described above, the present invention is not limited thereto, and various modifications are possible without departing from its spirit. For example, the machine tool 1 shown in the above embodiment is just one example, and it may be a turret lathe with a different configuration. Also, the fluid used to move the work guide 21 to the forward position may be an oil other than coolant. [Explanation of Symbols]

[0030] 1...Machine tool 3...First workpiece spindle unit 5...Turret unit 12...Spindle chuck 18...Tool post 21...Workpiece guide 23...Chuck cylinder 31...Inducer 39...Cylinder section 56...Guide contact member 57...Workpiece contact member 215,216...Annular groove 411...Coolant passage

Claims

1. A workpiece spindle device equipped with a spindle chuck that rotatably grips a workpiece, A turret device is provided in which multiple tools are mounted on a rotatable tool post, and the tools are moved relative to a workpiece held by the workpiece spindle device to perform machining. A control device for controlling the drive of the work spindle device and the turret device, It has, The workpiece spindle device is mounted so as to be movable back and forth on the axial portion of the spindle chuck and includes a workpiece guide that is inserted into the inner diameter portion of the workpiece when pushed out by fluid pressure. The turret device is mounted on the tool post and includes a pusher that pushes the work guide to a retracted position and presses the workpiece against the seating surface of the spindle chuck, in a machine tool.

2. The machine tool according to claim 1, wherein the workpiece spindle device has a coolant channel formed inside, and the workpiece guide is pushed to an advanced position by the pressure of the coolant.

3. The machine tool according to claim 2, wherein the work spindle device is incorporated into a cylinder portion formed in the spindle chuck such that the work guide, which has a piston portion formed on it, protrudes from the seating surface, and the work guide is pushed to the forward position by coolant supplied to the cylinder portion from the coolant passage.

4. The machine tool according to any one of claims 1 to 3, wherein the work spindle device has two annular grooves formed in the cylindrical work guide, and a plunger is provided in the guide holding portion that slidably holds the work guide, which fits into the annular grooves to position the work guide in an advanced position and a retracted position.

5. The machine tool according to claim 1, wherein the pusher comprises a central member that can be inserted into the inner diameter of a workpiece and an outer diameter member positioned on the outer diameter side of the central member and pressed against the workpiece, the central member being integrally provided with a rod-shaped support member, and the support member being slidably assembled to a holder member that can be attached to the tool post side, while being biased by a spring member.

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