Workpiece pressing device, machine tool, and workpiece pressing method

Abstract

To provide a workpiece pressing device, a machine tool and a workpiece pressing method capable of pressing a workpiece properly.SOLUTION: A workpiece pressing device 40 includes: a pusher 41 provided so as to be movable relative to a bed 11 in a prescribed axial direction and pushing a workpiece temporarily attached to a shaft toward the shaft along the prescribed axial direction; and an auxiliary pressure device 42 provided so as to be movable relative to the bed 11 in the prescribed axial direction and pushing, toward the shaft, the workpiece pushed by the pusher 41 along the prescribed axial direction.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present specification relates to a control device and a machine tool. [Background technology]

[0002] Conventionally, for example, a center pushing tool (hereinafter simply referred to as "pushing tool") for an NC lathe is known, as disclosed in Patent Document 1. This conventional pushing tool is a pusher that can be attached to and detached from the tool rest of a turret device to correct the center position of a workpiece, and is designed to be installed on an NC lathe equipped with a tailstock. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Utility Model Application Publication No. 5-78401 Summary of the Invention [Problem to be solved by the invention]

[0004] In the conventional pressing tool described above, the pusher is attached to the tool table of the turret device. Therefore, when the pusher presses the workpiece, there is a possibility that an excessive load is applied to the turret device. Therefore, with the conventional pressing tool, it is necessary to reduce the load on the turret device, which may result in the pusher not being able to press the workpiece in enough.

[0005] The present specification aims to provide a workpiece pressing device, a machine tool, and a workpiece pressing method that can press a workpiece appropriately. [Means for solving the problem]

[0006] This specification discloses a work pressing device that includes a pusher that is movable relative to the bed in a predetermined axial direction and presses a workpiece temporarily attached to the shaft along the predetermined axial direction toward the shaft, and an auxiliary pressing device that is movable relative to the bed in the predetermined axial direction and presses the workpiece pressed by the pusher toward the shaft along the predetermined axial direction.

[0007] With this, the pusher presses the workpiece temporarily attached to the shaft toward the shaft, and the auxiliary pressing device can further press the workpiece pressed by the pusher toward the shaft. Therefore, the workpiece pressing device can press the workpiece toward the shaft by eliminating insufficient pressing of the workpiece by the pusher. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic perspective view showing an entire machine tool. [Figure 2] FIG. 1 is a diagram for explaining a configuration of a machine tool. [Figure 3] FIG. 2 is a partial cross-sectional view for explaining the configuration of a workpiece pressing device. [Figure 4] FIG. 4 is a partial cross-sectional view for explaining a state in which the pusher of FIG. 3 presses the workpiece. [Figure 5] 4 is a partial cross-sectional view for explaining a state in which the auxiliary pressing device of FIG. 3 presses the workpiece. FIG. [Figure 6] FIG. 10 is a partial cross-sectional view illustrating a state in which the workpiece pressing device presses the workpiece according to a first modified example. [Figure 7] FIG. 10 is a partial cross-sectional view illustrating a state in which a workpiece pressing device presses a workpiece according to a second modified example. [Figure 8] FIG. 10 is a partial cross-sectional view illustrating a state in which an auxiliary pressing device of a workpiece pressing device presses a workpiece according to a third modified example. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, a workpiece pressing device, a machine tool, and a workpiece pressing method will be described with reference to the drawings. In this embodiment, a case will be described in which a machine tool, which is an NC lathe, performs cutting on a workpiece that has been pressed and positioned by a workpiece pressing device.

[0010] 1. Machine tools 10 1 and 2, the machine tool 10 is mounted on a bed 11 and includes a headstock 20, a machining head 30, and a workpiece pressing device 40. The machine tool 10 also includes a control device 12 that controls the operation of each of the headstock 20, the machining head 30, and the workpiece pressing device 40. The control device 12 is primarily composed of a computer device, and controls the operation of each of the headstock 20, the machining head 30, and the workpiece pressing device 40 by executing various programs (not shown).

[0011] In this embodiment, the bed 11 employs a slant bed structure in which the guide surface 111 is inclined toward the front of the machine body in the X-axis direction (the machine body longitudinal direction). However, it goes without saying that the bed 11 may employ a flat bed structure that does not have an inclined guide surface 111.

[0012] The headstock 20 rotatably supports the spindle 21, which is a shaft body having an axis O along the Z-axis direction (machine body width direction), which is a predetermined axis direction. The spindle 21 is rotationally driven, for example, by a spindle motor or the like. The headstock 20 is provided with a spindle chuck 22 that grips the workpiece W at the tip of the spindle 21. In this embodiment, as shown in FIG. 2 , the spindle 21 is provided with an insertion hole 211 to hold the shaft-shaped workpiece W. A push-out device 23 is incorporated inside the spindle 21 and moves the push-out shaft back and forth along the axis O using an actuator. Depending on the shape of the workpiece W, the insertion hole 211 and the push-out device 23 may be omitted.

[0013] 1 and 2, the machining head 30 includes a guide 31 extending in the Z-axis direction on the guide surface 111 of the bed 11, and a Z-axis slide 32 slidably assembled to the guide 31 and guided in the Z-axis direction. The machining head 30 also includes a pair of guide rails 33 extending in the X-axis direction on the Z-axis slide 32, and an X-axis slide 34 guided in the X-axis direction by the guide rails 33. The Z-axis slide 32 and the X-axis slide 34 are adapted to reciprocate along the guide 31 and the guide rail 33, respectively, by a servo motor, a ball screw mechanism, etc. (not shown).

[0014] 1, the machining head 30 is equipped with a turret device 35 supported on an X-axis slide 34. The turret device 35 has a polygonal tool table 36 that can rotate around a rotation axis parallel to the Z-axis. The turret device 35 selects, by rotation indexing, a predetermined tool 37 or pusher 41 appropriate for machining the workpiece W from among various tools 37 attached to each side of the tool table 36 and pushers 41 that form a workpiece pressing device 40 (described later).

[0015] Here, the machining head 30 is supported by an X-axis slide 34. Furthermore, the X-axis slide 34 is supported by a Z-axis slide 32. As a result, the machining head 30 can move in directions along the guide surface 111, i.e., in predetermined axial directions, that is, the Z-axis direction (machine body width direction), the X-axis direction (machine body front-rear direction), and the Y-axis direction (machine body up-down direction), by movement of the Z-axis slide 32 and the X-axis slide 34. Then, by the moved Z-axis slide 32 and X-axis slide 34, the machining head 30 is positioned at a machining position where a tool 37 machines the workpiece W, or at a pressing position where a workpiece pressing device 40 (described later) presses the workpiece W.

[0016] 2. Workpiece pressing device 40 1 and 2, the workpiece pressing device 40 includes a pusher 41 attached to the tool rest 36 of the turret device 35 in the machining head 30, and a tailstock 42 as an auxiliary pressing device provided so as to be movable relative to the bed 11. Here, the tailstock 42 is one device that forms the machine tool 10, and in this embodiment, the tailstock 42 is used as the auxiliary pressing device.

[0017] 2-1. Pusher 41 3, the pusher 41 has a base plate 411, a guide portion 412, a shaft 413 as a pressed portion, a spring 414, and a plate member 415. The base plate 411 is a member for attaching the pusher 41 to the tool table 36 of the turret device 35.

[0018] The guide portion 412 accommodates and guides the protrusion W1 provided on the workpiece W, and also presses the workpiece W. For this reason, the guide portion 412 has a conical recess whose inner diameter gradually decreases as it moves away from the protrusion W1 of the workpiece W. As a result, the guide portion 412 accommodates the protrusion W1 of the workpiece W, thereby guiding the workpiece W toward the axis O of the spindle 21, which is a shaft body.

[0019] 2, when the workpiece W is mounted on the headstock 20, the machining head 30 is positioned at a position where the workpiece pressing device 40 presses the workpiece W, and where the axis of the pusher 41 is coaxial with the axis O of the spindle 21 of the headstock 20. As a result, the guide portion 412 guides the workpiece W (protrusion W1) to the axis O of the spindle 21 of the headstock 20.

[0020] As shown in FIG. 3 , the shaft 413 has a fixing portion 413a at its tip end that coaxially fixes the guide portion 412, and an accommodating recess 416 at its base end that accommodates a pressing portion 421 of the tailstock 42, which will be described later. The accommodating recess 416 is formed coaxially with the shaft 413, in other words, coaxial with the axis of the pusher 41 including the guide portion 412. In this embodiment, as shown in FIG. 3 , when the pusher 41 is disposed in the pressing position, that is, when the pusher 41 is disposed coaxially with the axis O of the spindle 21, the accommodating recess 416 is coaxial with the axis O. The shaft 413 also has a large-diameter flange portion 413b approximately in the center, and the outer circumferential surface of the shaft 413 on the tip side of the flange portion 413b is slidably supported by a sliding bearing 417, and a spring 414 is disposed on the base end side of the flange portion 413b.

[0021] The spring 414 is housed between the flange portion 413b of the shaft 413 and a plate member 415 fixed to the base plate 411, and is supported radially by a collar 418. The spring 414 is compressed between the flange portion 413b and the plate member 415. As a result, the shaft 413 is constantly biased by a first pressing force F1 (see FIG. 4, for example) from the spring 414 in a direction in which the flange portion 413b abuts against a step formed inside the base plate 411. Therefore, the shaft 413 is biased in a direction in which the guide portion 412, which houses the protrusion W1 of the workpiece W, presses the workpiece W, i.e., in a direction along the axis O that coincides with the Z-axis direction, which is a predetermined axial direction.

[0022] Furthermore, the pusher 41 is equipped with a proximity switch 419 that outputs a signal according to the distance between the base plate 411 and the guide portion 412. The proximity switch 419 outputs an ON signal to the control device 12 when the distance between the base plate 411 and the guide portion 412 becomes less than a preset threshold, and outputs an OFF signal to the control device 12 when the distance is equal to or greater than the threshold. Here, the threshold is a value that is determined based on, for example, the magnitude of the load acting on the tool table 36 of the turret device 35. It goes without saying that a detector other than the proximity switch 419 can be used as long as it can detect the positional relationship between the base plate 411 and the guide portion 412.

[0023] 2-2. Tailstock 42 The tailstock 42 is used to center the workpiece W temporarily attached to the spindle 21. When used in a lathe, the tailstock 42 is also called a tailstock, and is arranged coaxially with the axis O of the spindle 21 of the headstock 20 in the Z-axis direction. As shown in FIGS. 2 and 3, the tailstock 42 includes a shaft-shaped pressing portion 421 and a support portion 422 that supports the pressing portion 421. The shaft-shaped pressing portion 421 has a pointed tip, and as shown by the dashed dotted line in FIG. 3, it moves relative to the bed 11 in the Z-axis direction (direction of the axis O), which is a predetermined axial direction, to be accommodated in an accommodating recess 416 formed in the shaft 413 of the pusher 41.

[0024] 2, the tailstock 42 is equipped with a pair of guide rails 423 extending in the Z-axis direction on the bed 11, and a drive unit 424 that reciprocates the pressing portion 421 and the support portion 422 along the Z-axis direction while being guided by the guide rails 423. The drive unit 424 reciprocates the pressing portion 421 and the support portion 422 along the guide rails 423, i.e., coaxially with the axis O of the spindle 21 of the headstock 20, by means of a servo motor, a ball screw mechanism, or the like (not shown). The operation of the drive unit 424 is controlled by the control device 12 of the machine tool 10.

[0025] When the drive unit 424 presses the pusher 41 with the pressing portion 421 housed in the housing recess 416 provided in the shaft 413, the drive unit 424 can, for example, use the driving force of a servo motor to press the pressing portion 421 with a second pressing force F2 (see, for example, FIG. 5 ) that is greater than the first pressing force F1. Incidentally, the tailstock 42 is provided on the bed 11 so as to be coaxial with the axis O of the spindle 21 of the headstock 20, and as described above, when the pusher 41 is disposed in the pressing position, it is coaxial with the axis O of the spindle 21 of the headstock 20. Therefore, when the pressing portion 421 of the tailstock 42 presses the pusher 41, the tailstock 42 presses the workpiece W toward the headstock 20 (spindle 21) via the pusher 41 with the second pressing force F2, i.e., in the direction of the axis O of the spindle 21.

[0026] 3. Operation of the workpiece pressing device 40 Next, the operation of the above-mentioned workpiece pressing device 40 will be described. When cutting a workpiece W in the machine tool 10, a predetermined tool 37 is selected by the rotational indexing of the turret device 35, and the machining head 30 is positioned at the machining position. Then, the workpiece W held by the spindle chuck 22 is rotated by the rotational drive of the headstock 20, and the blade of the tool 37 is brought into contact with the workpiece W, thereby performing machining such as outer diameter cutting.

[0027] Incidentally, when machine tool 10 performs automatic machining on workpiece W, for example, an automatic workpiece transport device (not shown) or the like is provided, and workpieces W are transported in order from a workpiece stocker. In this case, in order to maintain or improve the machining accuracy of the machining performed on workpiece W by machine tool 10, workpiece W needs to be properly held and mounted in spindle chuck 22 while always being arranged at a predetermined position on headstock 20 (spindle 21).

[0028] Therefore, in machine tool 10, control device 12 first selects pusher 41 of workpiece pressing device 40 attached to tool rest 36 by rotating and indexing turret device 35. Then, in this embodiment, workpiece pressing device 40 is operated to press workpiece W that has been transported and temporarily attached to spindle 21, which is a shaft, thereby pressing and arranging workpiece W at a predetermined position on spindle 21 (headstock 20). Below, a specific description will be given of a first step in which pusher 41 presses workpiece W toward spindle 21 (headstock 20), and a second step in which tailstock 42, which serves as an auxiliary pressing device, presses workpiece W pressed by pusher 41.

[0029] 3-1.First step In the first step, as shown in Fig. 2, the control device 12 drives the Z-axis slide 32 and the X-axis slide 34 to position the machining head 30, more specifically, the pusher 41 selected by the rotation index of the turret device 35, at the pressing position. As a result, the pusher 41 is arranged coaxially with the axis O of the main spindle 21, as shown in Fig. 4.

[0030] Next, the control device 12 moves the Z-axis slide 32 forward (relatively moves) toward the headstock 20, thereby moving the pusher 41 together with the turret device 35 (machining head 30) relatively to the bed 11 in the Z-axis direction, which is a predetermined axial direction, as shown by the thick dashed arrow in Fig. 4. As a result, the guide portion 412 of the pusher 41 receives the convex portion W1 of the workpiece W and presses the workpiece W toward the spindle 21 while guiding the workpiece W toward the axis O. As a result, the workpiece W temporarily attached to the spindle 21 moves relative to the spindle 21 (more specifically, the spindle chuck 22) so as to be coaxial with the axis O.

[0031] 3-2.Second process However, when the pusher 41 presses the workpiece W as the Z-axis slide 32 advances, a situation may arise in which the first pressing force F1 of the spring 414 is not enough to press the workpiece W, depending on, for example, the size and shape of the workpiece W. That is, in this case, the guide portion 412 and shaft 413 of the pusher 41 move rearward in the Z-axis direction relative to the base plate 411 against the first pressing force F1 of the spring 414. As a result, the load caused by the pressing of the workpiece W increases on the turret device 35 (tool table 36) that supports the pusher 41.

[0032] Therefore, in this embodiment, the control device 12 drives the drive device 424 of the tailstock 42 when an ON signal is received from the proximity switch 419, in other words, when the load on the tool post 36 of the turret device 35 becomes large. That is, in this embodiment, when assistance is required when the pusher 41 presses the workpiece W in the first step, the tailstock 42 is operated as an auxiliary pressing device in the second step to press the workpiece W.

[0033] Specifically, in the second step, the tailstock 42 advances in the Z-axis direction toward the headstock 20, i.e., the pusher 41 pressing the workpiece W, as shown by the thick dashed arrow in Fig. 5. As a result, the pressing portion 421 is accommodated in the accommodating recess 416 of the shaft 413, as shown in Fig. 5. Then, as the driving device 424 continues to be driven, the pressing portion 421 presses the shaft 413, which is the pressed portion, via the accommodating recess 416, with the second pressing force F2.

[0034] Here, in this embodiment, when the control device 12 receives an ON signal from the proximity switch 419, it stops the advancement (movement) of the Z-axis slide 32, i.e., the machining head 30, in the Z-axis direction. This allows the pusher 41 to apply the second pressing force F2 from the tailstock 42 to the first pressing force F1 from the spring 414, and press the workpiece W, without applying an excessive load to the tool rest 36 of the turret device 35 that forms the machining head 30.

[0035] In this case, the forward movement of the turret device 35 (machining head 30) stops, and the shaft 413 (and the guide portion 412) pressed by the tailstock 42 advances in the Z-axis direction relative to the base plate 411. Therefore, the compression of the spring 414 arranged between the flange portion 413b and the plate member 415 is gradually released, and the first pressing force F1 gradually decreases.

[0036] On the other hand, the tailstock 42 is driven by a drive device 424 having a servo motor or the like to move forward in the Z-axis direction, so that, for example, the second pressing force F2 can be increased in response to a decrease in the first pressing force F1, that is, the second pressing force F2 can be made greater than the first pressing force F1. Therefore, by being pressed (assisted) by the tailstock 42, the pusher 41 can press and push the workpiece W toward a predetermined position on the spindle 21 while the guide portion 412 guides the workpiece W to the axis O.

[0037] Then, for example, when the position of the workpiece W in the Z-axis direction grasped via the push-out device 23 incorporated inside the headstock 20 reaches a predetermined position, the control device 12 actuates the spindle chuck 22 to hold the workpiece W, thereby completing the attachment of the workpiece W to the headstock 20. As a result, the tailstock 42 and the Z-axis slide 32 move backward in the Z-axis direction, and the pusher 41 moves away from the workpiece W. Then, the control device 12 selects a tool 37 for cutting the workpiece W by rotating and indexing the turret device 35, and performs machining (cutting) on ​​the workpiece W.

[0038] As can be understood from the above explanation, the work pressing device 40 is provided with a pusher 41 that is movable relative to the bed 11 in the Z-axis direction, which is a predetermined axial direction, and presses the work W that is temporarily attached to the main spindle 21 as a shaft along the Z-axis direction, toward the main spindle 21, and a tailstock 42 that serves as an auxiliary pressing device that is movable relative to the bed 11 in the Z-axis direction and presses the work W pressed by the pusher 41 toward the main spindle 21 along the Z-axis direction.

[0039] According to this, in a first step, the pusher 41 presses the workpiece W temporarily attached to the spindle 21 toward the spindle 21, and further, in a second step, the tailstock 42 can press the workpiece W pressed by the pusher 41 toward the spindle 21. Therefore, by undergoing the first and second steps, the workpiece pressing device 40 can cause the tailstock 42 to eliminate the insufficient pressing of the workpiece W by the pusher 41 and press the workpiece W toward the spindle 21.

[0040] By eliminating the insufficient pressing, the workpiece W can be positioned at a predetermined position on the spindle 21, and the workpiece W can be finally attached to the spindle 21 by the spindle chuck 22. This allows the workpiece W to be always attached appropriately, which makes it possible to maintain and improve, for example, the machining accuracy of the machining performed on the workpiece W by the machine tool 10.

[0041] Furthermore, the existing tailstock 42 provided in the machine tool 10 can be used as the auxiliary pressing device. This eliminates the need to provide a separate auxiliary pressing device, which can reduce equipment costs, for example.

[0042] 4. Variations 4-1. First modified example In the embodiment described above, the advancement of the turret device 35 (machining head 30) is stopped when the tailstock 42 presses the pusher 41 in the second step. This makes it possible to position the workpiece W at a predetermined position on the spindle 21 while reducing the load on the tool rest 36 of the turret device 35. Alternatively, it is also possible to advance the turret device 35 (machining head 30) in synchronization with the advancement of the tailstock 42.

[0043] That is, in the second step, the control device 12 continuously advances the Z-axis slide 32, i.e., the turret device 35 (machining head 30), in the Z-axis direction, for example, in accordance with (synchronization with) the speed at which the tailstock 42 advances, as shown by the thick dashed arrow in Figure 6. This allows the pusher 41 to apply the second pressing force F2 from the tailstock 42 to the first pressing force F1 from the spring 414, thereby pressing the workpiece W. Therefore, the first modified example can achieve the same effects as the above-described embodiment.

[0044] In this case, in the second step, the turret device 35 (machining head 30) continues to move forward in synchronization with the tailstock 42, so the spring 414 continues to be compressed by the flange portion 413b of the shaft 413. Therefore, the first pressing force F1 by the spring 414 continues to act on the guide portion 412 and the shaft 413. In other words, in the first modified example, unlike the second step of the above-described embodiment, the pusher 41 can press the workpiece W with, for example, the maximum first pressing force F1, while the tailstock 42 can press (assist) the pusher 41 with the second pressing force F2.

[0045] 4-2. Second variant In the above-described embodiment and first modified example, the pusher 41 of the workpiece pressing device 40 presses the workpiece W in a first step. Then, in the above-described embodiment and first modified example, when an ON signal is received from the proximity switch 419, that is, when the load on the tool post 36 of the turret device 35 becomes large, the tailstock 42 presses the workpiece W via the pusher 41 in a second step. Alternatively, for example, if it is known in advance based on the shape and size of the workpiece W that the load on the tool post 36 of the turret device 35 will become large, the pusher 41 and the tailstock 42 may be connected in advance and the workpiece W may be pressed at the same time, as shown in FIG. 7 .

[0046] In the second modified example, as a first step, the pusher 41 is placed at the pressing position so as to be coaxial with the axis O of the headstock 20 (spindle 21), as in the above-described embodiment. Then, as shown in Fig. 7, for example, the control device 12 drives the drive device 424 of the tailstock 42, and the pressing portion 421 advances in the Z-axis direction and is accommodated in the accommodation recess 416 of the pusher 41, thereby connecting the pusher 41 and the tailstock 42.

[0047] In the second modified example, in a second step, for example, the control device 12 synchronously drives the Z-axis slide 32 and the drive device 424 as indicated by the thick dashed arrow in FIG. 7 . As a result, with the pusher 41 and the tailstock 42 coupled to each other, the guide portion 412 of the pusher 41 presses the workpiece W toward the spindle 21. In this case, as shown in FIG. 7 , the guide portion 412 and the shaft 413 of the pusher 41 move back slightly as they press the workpiece W, thereby generating a first pressing force F1 and pressing the workpiece W. Furthermore, the tailstock 42 is driven by the drive device 424 to generate a second pressing force F2 greater than the first pressing force F1, and presses the workpiece W toward the spindle 21 via the pusher 41. Therefore, the second modified example also provides the same effects as those of the above-described embodiment.

[0048] 4-3.Third modified example In the above-described embodiment and first modified example, the pusher 41 presses the workpiece W in a first step, and then the tailstock 42 presses the workpiece W via the pusher 41 in a second step. That is, in the above-described embodiment and first modified example, as shown in Figs. 5 and 6, while the pusher 41 is pressing the workpiece W, the tailstock 42 presses the pusher 41, thereby pressing the workpiece W.

[0049] Alternatively, for example, as shown in Fig. 4, after the pusher 41 presses the workpiece W in the first step, the control device 12 retracts the pusher 41 attached to the turret device 35 (machining head 30), and in the second step, the tailstock 42 can directly press the workpiece W after it has been pressed by the pusher 41, as shown in Fig. 8. In this case, as shown in Fig. 8, it is preferable that a recess W2 is provided in the convex portion W1 of the workpiece W to accommodate the tip of the pressing portion 421 of the tailstock 42.

[0050] As a result, in the third modified example, in the first step, the pusher 41 presses the workpiece W, whereby the workpiece W is guided to some extent toward the axis O of the spindle 21 and is positioned near a predetermined position on the spindle 21. Then, in the third modified example, in the second step, the tip of the pressing portion 421 of the tailstock 42 is directly received in the recess W2 formed in the protrusion W1 of the workpiece W, and the pressing portion 421 directly presses the workpiece W. As a result, the workpiece W becomes coaxial with the axis O and is pushed into and positioned at a predetermined position on the spindle 21. Therefore, in the third modified example, the same effects as those of the above-mentioned embodiment and first modified example can be obtained.

[0051] 4-4.Fourth modified example In the above-described embodiment and each of the above-described modified examples, a proximity switch 419 is provided. When the control device 12 acquires an ON signal output from the proximity switch 419, the tailstock 42 is automatically operated because the load on the tool post 36 of the turret device 35 is large. However, for example, when an operator operates the machine tool 10 manually, it is also possible to omit the proximity switch 419 and operate the tailstock 42 manually based on the operator's judgment, as in the above-described embodiment and each of the modified examples. Therefore, even in the case of the fourth modified example, the same effects as those of the above-described embodiment and each of the modified examples can be obtained.

[0052] 4-5. Fifth Modification In the above-described embodiment and each of the modified examples, the pusher 41 presses the workpiece W with a first pressing force F1 generated by a spring 414 as the turret device 35 (machining head 30) moves forward, and the tailstock 42 presses the workpiece W with a second pressing force F2 generated by a drive device 424 having a servo motor or the like. In other words, the above-described embodiment and each of the modified examples have been described by way of example with the case where the second pressing force F2 is greater than the first pressing force F1.

[0053] However, the magnitudes of the first pressing force F1 and the second pressing force F2 are not limited to the second pressing force F2 being greater than the first pressing force F1. In other words, as long as the workpiece W can be pushed and positioned at a predetermined position on the spindle 21, the second pressing force F2 applied to the workpiece W by the tailstock 42 may be smaller than the first pressing force F1 applied to the workpiece W by the pusher 41. In this way, even in the fifth modified example in which the magnitudes of the first pressing force F1 and the second pressing force F2 are not limited, the same effects as those of the above-described embodiment and each of the above-described modified examples can be expected.

[0054] 4-6. Sixth Modification In the above-described embodiment and each of the above-described modified examples, the pusher 41 is mounted to the tool table 36 of the turret device 35. As a result, the pusher 41 is provided so as to be movable relative to the bed 11 in the Z-axis direction, which is a predetermined axial direction, and presses the workpiece W temporarily attached to the spindle 21 toward the spindle 21 along the Z-axis direction. However, the attachment target of the pusher 41 is not limited to the tool table 36 of the turret device 35, and the pusher 41 may be provided in any location as long as it can press the workpiece W temporarily attached to the spindle 21. In this way, the same effects as those of the above-described embodiment and each of the above-described modified examples can be expected even in the sixth modified example, which does not limit the attachment target of the pusher 41.

[0055] However, when the pusher 41 is provided somewhere other than the tool table 36 of the turret device 35, it is preferable to provide the pusher 41 with a drive device equivalent to the Z-axis slide 32 so that the pusher 41 is movable relative to the bed 11 in the Z-axis direction, which is the predetermined axial direction, and presses the workpiece W temporarily attached to the spindle 21 toward the spindle 21. Note that, for example, in a machine tool in which the headstock 20 is configured to be movable relative to the bed 11 in the Z-axis direction, which is the predetermined axial direction, it is possible to omit the drive device because there is no need to move the pusher 41.

[0056] 4-7. Seventh Modification In the above-described embodiment and each of the above-described modified examples, the tailstock 42 is provided with a drive unit 424 that is guided in the Z-axis direction by a pair of guide rails 423, and the drive unit 424 is driven to move the pressing unit 421 relative to the bed 11. Alternatively or in addition to this, it is also possible to provide an actuator 425 that moves the pressing unit 421 and the support unit 422 relatively in the Z-axis direction, which is the predetermined axial direction, as shown by the two-dot chain line in Fig. 2 .

[0057] In this case, too, the actuator 425 is driven to cause the pressing portion 421 to press the workpiece W directly or via the pusher 41. Therefore, in the seventh modified example, the same effects as those of the above-described embodiment and each of the above-described modified examples can be obtained.

[0058] 4-8. Eighth Modification In the above-described embodiment and each of the modified examples, the shaft 413 of the pusher 41 is provided with an accommodating recess 416, and the pressing portion 421 of the tailstock 42 is accommodated in the accommodating recess 416. This ensures that the pusher 41 and the pressing portion 421 of the tailstock 42 are coaxial with the axis O. The tailstock 42 is mounted on the bed 11 so as to be coaxial with the axis O of the spindle 21 of the headstock 20. Therefore, although there is a possibility of some variation when the pressing portion 421 presses the pusher 41, it is possible to achieve a state in which the pusher 41 and the pressing portion 421 are approximately coaxial with the axis O. Therefore, it is possible to omit the accommodating recess 416, and even in this case, the same effects as those of the above-described embodiment and each of the modified examples can be expected. [Explanation of symbols]

[0059] 10...machine tool, 11...bed, 111...guide surface, 12...control device, 20...headstock, 21...spindle (shaft body), 211...through hole, 22...spindle chuck, 23...extrusion device, 30...machining head, 31...guide, 32...Z-axis slide, 33...guide rail, 34...X-axis slide, 35...turret device, 36...tool table, 37...tool, 40...workpiece pressing device, 41...pusher, 411...base plate, 41 2...Guide portion, 413...Shaft, 413a...Fixed portion, 413b...Flange portion, 414...Spring, 415...Plate member, 416...Accommodating recess, 417...Slide bearing, 418...Collar, 419...Proximity switch, 42...Tailstock (auxiliary pressing device), 421...Pressing portion, 422...Support portion, 423...Guide rail, 424...Drive device, 425...Actuator, W...Workpiece, W1...Convex portion, W2...Concave portion, O...Axis center

Claims

1. a pusher that is provided so as to be movable relative to the bed in a predetermined axial direction and that presses a workpiece temporarily attached to a shaft body along the predetermined axial direction toward the shaft body; a workpiece pressing device provided so as to be movable relative to the bed in the predetermined axial direction, and which presses the pusher, which is pressing the workpiece along the predetermined axial direction, toward the shaft.

2. The workpiece pressing device according to claim 1 , wherein the pusher and the auxiliary pressing device press the workpiece toward the shaft body while being connected to each other.

3. The pusher presses the workpiece with a first pressing force; The workpiece pressing device according to claim 1 or 2, wherein the auxiliary pressing device presses the workpiece toward the shaft body with a second pressing force that is greater than the first pressing force.

4. The workpiece pressing device according to any one of claims 1 to 3, wherein the pusher has an accommodating recess in a pressed portion pressed by the auxiliary pressing device, the accommodating recess accommodating the shaft-shaped pressing portion of the auxiliary pressing device.

5. The workpiece pressing device according to claim 4 , wherein the accommodating recess is disposed coaxially with the axis of the pusher.

6. The workpiece pressing device according to any one of claims 1 to 5, wherein the pusher has a guide portion that receives a convex portion formed on the workpiece and guides the workpiece to the axis of the shaft body.

7. The workpiece pressing device according to any one of claims 1 to 6 is provided, A machine tool that performs machining on the workpiece positioned at a predetermined position on the spindle, which is the shaft body, by the workpiece pressing device.

8. The pusher is provided on a tool table that can select one of a plurality of tools for performing the machining on the workpiece by turning and indexing, 8. The machine tool according to claim 7, wherein the auxiliary pressing device is a tailstock that performs centering of the workpiece temporarily attached to the spindle.

9. 9. The machine tool according to claim 8, wherein the tailstock presses the pusher, which is pressing the workpiece, along the predetermined axial direction, thereby pressing the workpiece toward the spindle.

10. The machine tool according to claim 8 or 9, wherein the pusher and the tailstock press the workpiece toward the spindle while being connected to each other.

11. The machine tool according to any one of claims 8 to 10, wherein the tailstock, together with the pusher, presses the workpiece toward the spindle, and after the workpiece is positioned at the predetermined position on the spindle, the workpiece is fixed and attached to the spindle.

12. The present invention is applied to the workpiece pressing device according to any one of claims 1 to 6, a first step in which the pusher presses the workpiece temporarily attached to the shaft toward the shaft along the predetermined axial direction; a second step in which the auxiliary pressing device presses the pusher, which is pressing the workpiece, toward the shaft along the predetermined axial direction.

13. In the second step, 13. The workpiece pressing method according to claim 12, wherein the auxiliary pressing device presses the pusher, which is pressing the workpiece in the first step, along the predetermined axial direction, thereby pressing the workpiece toward the shaft body.

14. The present invention is applied to the workpiece pressing device according to any one of claims 1 to 6, a first step of connecting the auxiliary pressing device to the pusher; a second step of pressing the workpiece temporarily attached to the shaft body toward the shaft body while the pusher and the auxiliary pressing device are connected to each other.

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