lathe

Abstract

The present invention provides a lathe capable of shortening a spindle in the direction of the spindle center line. A spindle (52) having a holding portion (60) disposed at the front is rotatably supported on a support portion (53) via bearings (B1, B2). An opening and closing device (6) comprises a claw component (20) and a shifter (10) for opening and closing the holding portion (60). Between the front bearing (B1) and the rear bearing (B2), a built-in motor (55) for rotating the spindle (52) and a claw component (20) capable of tilting on the outside of the spindle (52) are arranged. The claw component (20) comprises a movable end portion (21), and the distance of the movable end portion (21) from the spindle center line (AX0) changes between a first posture (PO1) in which the holding portion (60) is in an open state (ST1) and a second posture (PO2) in which the holding portion (60) is in a closed state (ST2). The shifter (10) is movable outside the claw member (20) toward the spindle centerline and is arranged at a first position (LO1) for setting the claw member (20) in a first posture (PO1) and a second position (LO2) for setting the claw member (20) in a second posture (PO2).

Description

Technical Field

[0001] The present invention relates to a lathe having a main spindle provided with a holding portion for releasably holding a workpiece. Background Art

[0002] As a lathe, there is a known NC (Numerical Control) lathe that performs front processing on a workpiece held on a front spindle and delivers the workpiece after the front processing to a back spindle for back processing. The front spindle and the back spindle have a holding portion such as a collet at the front to hold the workpiece. As shown in Patent Document 1, the support portion of the spindle supports the spindle rotatably via a front bearing and a rear bearing. An internal motor that rotates the spindle is arranged between the front bearing and the rear bearing. The clamping mechanism for opening and closing the collet is arranged further back than the rear bearing. Here, the clamping mechanism includes: a shifter that can move in the direction of the spindle centerline on the outside of the spindle; and a claw member that has a front end that protrudes forward and contacts the outer peripheral surface of the shifter, and can tilt in the direction of the distance change from the spindle centerline to the front end. The shifter is a shape that surrounds the spindle with the spindle centerline as the center. A plurality of claw members are in contact with the shifter. The shifter and the claw member rotate around the spindle centerline as the center. Here, since the front end of the claw member is present outside the shifter centered on the spindle centerline, the clamping mechanism is referred to as an outer-claw type clamping machine.

[0003] If the shifter is driven to the rear side, the claw member is tilted in a direction in which the front end of the claw member is away from the center line of the spindle, and the collet is closed through the sleeve member. As a result, the workpiece is held by the collet. In addition, if the shifter is driven to the front side, the claw member is tilted in a direction in which the front end of the claw member is close to the center line of the spindle due to the force from the collet opening spring, and the collet is opened. As a result, the workpiece is released from the collet.

[0004] As described above, the shifter and the claw member rotate around the spindle centerline. In order to prevent the front end of the claw member from moving away from the spindle centerline due to centrifugal force when the shifter is driven, the claw member is configured to extend rearward relative to the tilting center. The shifter is configured to extend forward from the vicinity of the front end of the claw member.

[0005] Background Art Literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Laid-Open No. 2018-149643 (especially Figure 2 ) Summary of the invention

[0008] [Problems to be solved by the invention]

[0009] In order to avoid interference between the spindle stand and structures such as the tool holder that move in the direction of the spindle center line, the front part of the spindle supported by the support part is sometimes extended. However, the clamping mechanism located further back than the rear bearing cannot be simply moved between the front bearing and the rear bearing where the built-in motor exists. The reason is that the clamping mechanism is longer in the direction of the spindle center line, and if there is no intermediate bearing between the front bearing and the rear bearing and between the clamping mechanism and the built-in motor, the support part cannot support the spindle to rotate at high speed. Therefore, when both the clamping mechanism and the built-in motor are arranged between the front bearing and the rear bearing, the structure of the spindle stand becomes complicated, and the front side of the spindle becomes too long.

[0010] Furthermore, the problems as described above exist in various lathes.

[0011] The invention discloses a lathe capable of shortening a main shaft in the direction of the main shaft center line.

[0012] [Technical means to solve the problem]

[0013] The lathe of the present invention has the following form, and comprises: a spindle, a holding portion having a closed state for holding a workpiece and an open state for releasing the workpiece is provided at the front, and can rotate around the center line of the spindle;

[0014] A support portion rotatably supports the main shaft via a front bearing and a rear bearing;

[0015] a built-in motor disposed between the front bearing and the rear bearing and causing the main shaft to rotate; and

[0016] An opening and closing device, which opens and closes the holding portion;

[0017] The opening and closing device comprises:

[0018] a claw member, which is arranged between the front bearing and the rear bearing on the outside of the main shaft, is tiltable, and has a movable end portion, the distance of which from the center line of the main shaft changes between a first posture in which the retaining portion is in an open state and a second posture in which the retaining portion is in a closed state; and

[0019] The shifter is movable outside the claw member in the direction of the spindle centerline and is arranged at a first position where the claw member is in a first posture and a second position where the claw member is in a second posture.

[0020] [Effects of the Invention]

[0021] According to the present invention, it is possible to provide a lathe in which a main spindle is shortened in the main spindle centerline direction. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a diagram schematically showing a configuration example of a lathe.

[0023] Figure 2 It is a longitudinal sectional view schematically showing an example of a sub-spindle stock.

[0024] Figure 3 It is a perspective view showing an example of a clamping mechanism and its surroundings.

[0025] Figure 4 This is a longitudinal sectional view showing an example of a clamping mechanism and its surroundings.

[0026] Figure 5 It is a perspective view showing an example of a claw member.

[0027] Figure 6 It is a perspective view showing an example of a claw holder.

[0028] Figure 7 It is a perspective view showing an example of a shifter.

[0029] Figure 8 It is a diagram schematically showing an example of a driving unit of a shifter.

[0030] Fig. 9 This is a longitudinal sectional view showing an example of the clamping mechanism when the holding portion is in an open state.

[0031] Fig.10 2 is a longitudinal sectional view showing an example of the clamping mechanism at a time point when the shifter reaches the second position that closes the retaining portion.

[0032] Fig.11 This is a longitudinal sectional view showing an example in which the insertion portion of the shift rod is separated from both side surfaces of the outward groove when the shifter is located at the second position.

[0033] Fig.12 2 is a longitudinal sectional view showing an example of the clamping mechanism at a time point when the shifter reaches the first position to open the retaining portion.

[0034] Fig.13 This is a longitudinal sectional view showing an example of a state in which a holding portion is in a closed state in an example in which a roller is provided on a shifter of an outer claw type clamping mechanism.

[0035] Fig.14 This is a longitudinal sectional view showing an example of a state where the holding portion is in an open state in an example where a roller is provided on the shifter of the outer claw type clamp mechanism.

[0036] Fig.15 This is a longitudinal sectional view showing an example of a state where the holding portion is in a closed state in an example where a roller is provided on the claw member of the inner claw type clamping mechanism.

[0037] Fig.16 This is a longitudinal sectional view showing an example of a state where the holding portion is in an open state in an example where a roller is provided on the claw member of the inner claw type clamping mechanism. DETAILED DESCRIPTION

[0038] The following will describe embodiments of the present invention. Of course, the following embodiments are merely illustrative of the present invention, and all features disclosed in the embodiments are not necessarily essential to the solution means of the invention.

[0039] (1) Overview of the technology included in the present invention:

[0040] First, refer to Figures 1 to 16 The examples shown illustrate the outline of the technology included in the present invention. In addition, the figures of this case are schematic diagrams of examples, and the magnifications of the directions shown in these figures are sometimes different, and the figures sometimes do not match. Of course, the elements of the present technology are not limited to the specific examples shown by the symbols.

[0041] [Form 1]

[0042] A lathe 1 of one form of the present technology includes a main shaft (for example, a back main shaft 52), a support portion 53, a built-in motor 55, and an opening and closing device 6. The main shaft 52 is provided with a holding portion 60 having a closed state ST2 for holding a workpiece W0 and an open state ST1 for releasing the workpiece W0 at the front, and is rotatable around the main shaft centerline AX0. The support portion 53 rotatably supports the main shaft 52 via the front bearing B1 and the rear bearing B2. The built-in motor 55 is arranged between the front bearing B1 and the rear bearing B2 and rotates the main shaft 52. The opening and closing device 6 has a claw member 20 and a shifter 10 to open and close the holding portion 60. The claw member 20 is arranged between the front bearing B1 and the rear bearing B2 on the outside of the main shaft 52 and is tiltable. The claw member 20 has a movable end portion 21, and the distance of the movable end portion 21 from the spindle center line AX0 changes between a first posture PO1 when the holding portion 60 is in an open state ST1 and a second posture PO2 when the holding portion 60 is in a closed state ST2. The shifter 10 can move in the direction of the spindle center line AX0 (for example, the Z-axis direction) outside the claw member 20, and is configured at a first position LO1 where the claw member 20 is in the first posture PO1 and a second position LO2 where the claw member 20 is in the second posture PO2.

[0043] For comparison, refer to Fig.13 , 14 , a brief description is given of the outer claw type clamping mechanism arranged further rearward than the rear bearing. Fig.13 , 14The back spindle clamping mechanism 6b shown includes: a shifter 10, which can move in the Z-axis direction on the outside of the back spindle 52; and a claw member 20, which protrudes forward and contacts the outer periphery of the shifter 10, and can tilt in the direction of the change in the distance from the spindle center line AX0 to the movable end 21. The shifter 10 is shaped so as to surround the back spindle 52 with the spindle center line AX0 as the center. A plurality of claw members 20 are in contact with the shifter 10. The shifter 10 and the claw member 20 rotate around the spindle center line AX0. As shown in FIG. Fig.14 As shown, in order to prevent the movable end 21 of the claw member 20 from moving away from the spindle center line AX0 due to centrifugal force when the shifter 10 is driven forward, the claw member 20 is shaped to extend rearwardly relative to the tilting center and has a weighted extension 22c. In addition, the shifter 10 is shaped to extend forward from the vicinity of the front end of the claw member 20.

[0044] According to the above, the outer claw type clamping mechanism is long in the direction of the spindle centerline and cannot be simply moved between the front bearing and the rear bearing where the built-in motor exists. In order to support the spindle where the clamping mechanism and the built-in motor are arranged between the front bearing and the rear bearing so that it can rotate at high speed, an intermediate bearing is required. However, when the intermediate bearing is used, the structure of the spindle table becomes complicated and the front side of the spindle becomes too long. In addition, the clamping mechanism is arranged further behind the rear bearing, which becomes disadvantageous in terms of high-speed rotation of the spindle.

[0045] On the other hand, in the clamping mechanism 6a of the above-mentioned form 1, the shifter 10 is arranged outside the claw member 20 located outside the spindle 52 so as to be movable in the direction of the spindle centerline AX0. Therefore, the clamping mechanism 6a of this form can be shorter in the spindle centerline direction than the outer claw type clamping mechanism, and can be arranged between the front bearing B1 and the rear bearing B2 where the built-in motor 55 exists even without an intermediate bearing. In the case where the front part of the spindle 52 must be lengthened for reasons such as avoiding interference between the spindle table 51 and the tool rest 30, the clamping mechanism 6a can be arranged in the space on the front side of the lengthened spindle 52, and the rear side of the spindle 52 can be shortened. Therefore, this form can provide a lathe with a spindle shortened in the spindle centerline direction.

[0046] Here, the main axis includes a main main axis also called a front main axis and a sub-main axis also called a back main axis.

[0047] The holding portion includes a mechanism for holding the workpiece using various holding units such as a collet or a claw.

[0048] The concept of artifacts also includes products.

[0049] In addition, the above-mentioned remarks also apply to the following forms.

[0050] [Form 2]

[0051] The lathe 1 may also include: a main spindle table (for example, the front spindle table 41) provided with a main spindle (for example, the front spindle 42) holding the workpiece W0; a tool rest 30 for processing the workpiece W0 held by the main spindle 42; and a sub-spindle table (for example, the back spindle table 51) provided with a sub-spindle (for example, the back spindle 52) as the spindle facing the main spindle 42 and receiving the workpiece W0 from the main spindle 42. The sub-spindle table 51 moving in the spindle centerline direction must avoid interference with the tool rest 30 for processing the workpiece W0 held by the main spindle 42. In the case where the front portion of the sub-spindle 52 must be lengthened for reasons such as avoiding interference between the sub-spindle table 51 and structures such as the tool rest 30, the clamping mechanism 6a can be arranged in the space on the front side of the lengthened sub-spindle 52, so that the rear side of the sub-spindle 52 can be shortened. In this way, this aspect can provide a lathe in which the sub-spindle is shortened in the main spindle centerline direction.

[0052] [Form 3]

[0053] Here, the claw member 20 and the shifter 10 can also be located further forward than the built-in motor 55 in the direction of the spindle centerline AX0. The diameter of the built-in motor 55 centered on the spindle centerline AX0 is relatively large, and on the other hand, the diameter of the clamping mechanism 6a can be relatively small. Therefore, it is easy to put the clamping mechanism 6a in the space on the front side where the spindle 52 is lengthened for reasons such as avoiding interference with structures such as the tool holder 30. In addition, the distance from the holding portion 60 located at the front of the spindle 52 to the clamping mechanism 6a is shortened, so the structure of the opening and closing device 6 of the holding portion 60 can be simplified. Therefore, this form can provide a suitable lathe that shortens the spindle in the direction of the spindle centerline.

[0054] [Form 4]

[0055] In addition, a lathe 1 of another form of the present technology includes a spindle (e.g., a back spindle 52) and an opening and closing device 6. The spindle 52 is provided with a holding portion 60 having a closed state ST2 for holding a workpiece W0 and an open state ST1 for releasing the workpiece W0, and is rotatable around the spindle centerline AX0. The opening and closing device 6 includes a claw member 20 and a shifter 10, which open and close the holding portion 60. The claw member 20 can tilt outside the spindle 52, and has a first posture PO1 in which the holding portion 60 is in the open state ST1 and a second posture PO2 in which the holding portion 60 is in the closed state ST2. The shifter 10 can move outside the spindle 52 in the direction of the spindle centerline AX0 (e.g., the Z-axis direction), and is configured at a first position LO1 in which the claw member 20 is in the first posture PO1 and a second position LO2 in which the claw member 20 is in the second posture PO2. A roller 15 is mounted on the shifter 10 at a position where the shifter 10 contacts the claw member 20 so as to be rollable in the direction of the main shaft center line AX0.

[0056] In the form 4, since the roller 15 installed on the shifter 10 is in contact with the claw member 20, when the retaining portion 60 is opened and closed, the roller 15 rolls in the direction of the center line of the main shaft. As a result, the friction between the shifter 10 and the claw member 20 is reduced, and the load on the driving source of the shifter 10 is reduced. In addition, the wear of the roller 15 and the claw member 20 can be reduced. Furthermore, although it takes time to extract the entire shifter around the main shaft 52 and install a new one around the main shaft 52, this form does not need to replace the entire shifter even if the roller 15 must be replaced, so the work of replacement can be reduced. In addition, when the roller is installed on the claw member, because the roller is in contact with the shifter, the roller and the shifter gradually wear out, and it becomes necessary to replace the entire shifter. By installing the roller on the shifter, the contact portion between the shifter and the claw member is limited to the roller, and there is no need to replace the entire shifter. Therefore, this aspect can provide a lathe that facilitates maintenance of the clamping mechanism.

[0057] [Form 5]

[0058] The shifter 10 may also have a retaining portion 14 on which an axial component (e.g., a roller pin 16) along the central axis AX3 of the rolling of the roller 15 is removably mounted. The roller 15 may also have a through hole 15a through which the axial component 16 passes in the direction of the central axis AX3, and can roll around the axial component 16 passing through the through hole 15a. In this form, if the axial component 16 is removed from the retaining portion 14 of the shifter 10, the roller 15 can be removed from the shifter 10, and if the axial component 16 of the roller 15 passing through the through hole 15a is mounted on the retaining portion 14 of the shifter 10, the replacement of the roller 15 is completed. Therefore, this form can provide a suitable lathe that makes it easy to maintain the clamping mechanism.

[0059] [Form 6]

[0060] Furthermore, a lathe 1 of another form of the present technology includes a spindle (e.g., a back spindle 52) and an opening and closing device 6. The spindle 52 is provided with a holding portion 60 having a closed state ST2 for holding a workpiece W0 and an open state ST1 for releasing the workpiece W0, and is rotatable around the spindle center line AX0. The opening and closing device 6 includes a claw member 20, a shifter 10, and a drive unit DR1, which open and close the holding portion 60. The claw member 20 rotates around the spindle center line AX0 on the outside of the spindle 52, and is tiltable, and has a first posture PO1 in which the holding portion 60 is in the open state ST1 and a second posture PO2 in which the holding portion 60 is in the closed state ST2. The shifter 10 rotates around the spindle center line AX0 on the outside of the spindle 52. The shifter 10 is movable in the direction of the spindle centerline AX0 (for example, the Z-axis direction), and is arranged at a first position LO1 where the claw member 20 is in the first posture PO1 and a second position LO2 where the claw member 20 is in the second posture PO2. The driving unit DR1 has a shift rod 68 that moves the shifter 10 in the direction of the spindle centerline AX0. An outward groove 12 is provided on the outer surface 11 of the shifter 10, which is centered around the spindle centerline AX0 and into which the insertion portion 68a of the shift rod 68 enters. A shifter bearing B3 is provided on the insertion portion 68a of the shift rod 68, which can contact the side surfaces 12a and 12b of the outward groove 12. In the claw member 20 and the shifter 10, for one member, a roller 15 capable of rolling in the direction of the spindle centerline AX0 is provided at a position in contact with the other member, and for the other member, a groove 25 is provided for the roller 15 to enter when the retaining portion 60 is in the open state ST1.

[0061] In the sixth embodiment, when the retaining portion 60 is in the open state ST1, the roller 15 located in one of the claw member 20 and the shifter 10 enters the groove 25 located in the other. Thus, even if the retaining portion 60 is in the open state ST1, the shifter bearing B3 can be kept separated from the side surfaces 12a and 12b of the outward groove 12 of the shifter 10. Therefore, the present embodiment can provide a lathe capable of extending the life of the shifter bearing.

[0062] [Form 7]

[0063] Furthermore, the lathe 1 according to another aspect of the present technology also has the following aspects.

[0064] A lathe 1 comprises: a spindle (e.g., a back spindle 52) having a holding portion 60 having a closed state ST2 for holding a workpiece W0 and an open state ST1 for releasing the workpiece W0, and being rotatable about a spindle centerline AX0; and

[0065] An opening and closing device 6, which opens and closes the holding portion 60;

[0066] The opening and closing device 6 has:

[0067] The claw member 20 is rotatable around the main shaft center line AX0 outside the main shaft 52, and can be tilted, and has a first posture PO1 in which the holding portion 60 is in an open state ST1 and a second posture PO2 in which the holding portion 60 is in a closed state ST2;

[0068] The shifter 10 is rotatable about the spindle center line AX0 on the outside of the spindle 52 and can be moved in the direction of the spindle center line AX0 (for example, the Z-axis direction), and is configured at a first position LO1 that makes the claw member 20 in the first posture PO1 and a second position LO2 that makes the claw member 20 in the second posture PO2; and

[0069] The driving unit DR1 has a shift rod 68 for moving the shifter 10 in the direction of the spindle centerline AX0;

[0070] On the outer surface 11 of the shifter 10, an outward groove 12 is provided which is around the main axis AX0 and is provided for the insertion portion 68a of the shift rod 68 to enter;

[0071] A shifter bearing B3 capable of contacting the side surfaces 12a, 12b of the outward groove 12 is provided at the insertion portion 68a of the shift rod 68; and

[0072] The driving unit DR1 drives the shift rod 68 so that the shifter bearing B3 is separated from the side surfaces 12 a and 12 b of the outward groove 12 after moving the shifter 10 in the direction of the spindle centerline AX0 .

[0073] In the seventh embodiment, after the shifter 10 is moved in the direction of the spindle centerline AX0 by the shift rod 68 driven by the drive unit DR1, the shifter bearing B3 is separated from the side surfaces 12a and 12b of the outward groove 12 of the shifter 10. Thus, the state in which the shifter bearing B3 is separated from the side surfaces 12a and 12b of the outward groove 12 of the shifter 10 can be maintained. Therefore, the present embodiment can provide a lathe capable of extending the life of the shifter bearing.

[0074] (2) Specific example of the structure of a lathe:

[0075] Figure 1 The configuration of a spindle-moving type NC (numerical control) lathe 1 in which the front spindle 42 moves is schematically illustrated as an example of a lathe. Figure 1 This is only a simplified example for explaining the present technology, and does not limit the present technology. In addition, the description of the positional relationship of each part is only for example. Therefore, changing the left and right direction to the up and down direction or the front and back direction, or changing the up and down direction to the left and right direction or the front and back direction, or changing the front and back direction to the left and right direction or the up and down direction, or changing the rotation direction to the opposite direction, etc. are also included in the present technology. In addition, the same direction or position is not limited to strict consistency, and includes situations where it deviates from strict consistency due to errors.

[0076] Figure 1 The lathe 1 shown has a front spindle head 41 on which a front spindle 42 is installed, a guide sleeve 35, a back spindle head 51 on which a back spindle 52 is installed, a comb-shaped tool rest 31, a back processing tool rest 32, a turret tool rest 33, etc. on a base 2. In addition, the front spindle 42 is an example of a main spindle, the front spindle head 41 is an example of a main spindle head, the back spindle 52 is an example of a sub-spindle, and the back spindle head 51 is an example of a sub-spindle head. In addition, the comb-shaped tool rest 31, the back processing tool rest 32, and the turret tool rest 33 are collectively referred to as a tool rest 30. Figure 1 For convenience, an NC device (numerical control device) 80 for numerically controlling the movement of the spindle table 41, 51 or the guide sleeve 35 or the tool holder 30 is also shown, but the NC device 80 is not limited to the one located at Figure 1 Position shown.

[0077] Figure 1In the figure, the front spindle stage 41 including the front spindle 42 can move in the Z-axis direction, the back spindle stage 51 including the back spindle 52 can move in the Z-axis direction and the X-axis direction, the comb tool holder 31 can move in the X-axis direction and the Y-axis direction, the back processing tool holder 32 can move in the Y-axis direction, and the turret tool holder 33 can move in the X-axis direction, the Y-axis direction and the Z-axis direction. Here, the Z-axis direction is an example of the direction of the spindle centerline, the Z-axis direction and the X-axis direction are orthogonal to each other, the Z-axis direction and the Y-axis direction are orthogonal to each other, and the X-axis direction and the Y-axis direction are orthogonal to each other. In addition, the Z-axis direction and the X-axis direction may or may not be orthogonal, the Z-axis direction and the Y-axis direction may or may not be orthogonal, and the X-axis direction and the Y-axis direction may or may not be orthogonal. Of course, the moving direction of the spindle stage 41, 51 or the tool holder 30 is not limited to. Figure 1 direction shown.

[0078] The base 2 is also called a base or a stage, and constitutes a basic part that directly or indirectly supports the above-mentioned parts 41, 35, 51, 30, etc. Figure 1 It is shown that the base 2 supports the guide sleeve 35 via the support 36 .

[0079] The front spindle 42 has a holding portion such as a collet, and the holding portion can releasably hold the cylindrical (rod-shaped) workpiece W1 inserted in the Z-axis direction. The NC device 80 rotates the front spindle 42 around the spindle centerline AX1 along the length direction of the workpiece W1 via a drive portion such as a built-in motor. As a result, the front spindle 42 rotates the workpiece W1 around the spindle centerline AX1.

[0080] The guide sleeve 35 disposed in front of the front spindle 42 supports the long workpiece W1 passing through the front spindle 42 so that it can slide in the Z-axis direction, and is driven to rotate about the spindle centerline AX1 in synchronization with the front spindle 42. In addition, the present technology can also be applied to lathes without guide sleeves.

[0081] The back spindle 52 faces the front spindle 42 and receives the front-machined workpiece W0 from the front spindle 42. The back spindle 52 has a holding portion 60 such as a collet, and the holding portion 60 can releasably hold the front-machined workpiece W0 inserted in the Z-axis direction when the spindle center lines AX1 and AX0 are aligned with each other. Figure 2The driving unit such as the built-in motor 55 shown in the figure rotates the back spindle 52 around the spindle center line AX0. As a result, the back spindle 52 rotates the workpiece W0 around the spindle center line AX0. The back spindle 52 is sometimes referred to as an opposing spindle in the sense of being opposite to the front spindle. Hereinafter, in the case of including both the spindle center line AX1 of the front spindle 42 and the spindle center line AX0 of the back spindle 52, it is simply referred to as the spindle center line AX0, and in the case of including both the workpiece W1 held by the front spindle 42 and the workpiece W0 held by the back spindle 52, it is simply referred to as the workpiece W0.

[0082] A plurality of tools T1 for processing the workpiece W0 are mounted on the tool rest 30. The comb tool rest 31 and the turret tool rest 33 can perform front processing on the workpiece W1 supported on the guide sleeve 35 by various tools T1. The plurality of tools T1 include cutting tools for cutting the workpiece W0 held by the two spindles 42 and 52. The back processing tool rest 32 and the turret tool rest 33 can perform back processing on the workpiece W0 separated by the cutting tools after the front processing.

[0083] The NC device 80 has a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), a clock circuit, an interface (I / F), etc., and receives input of various information from an operation panel (not shown) or an external computer and executes an NC program. Thus, the NC device 80 controls the movement of the spindle table 41, 51 or the tool rest 30, and the rotation of the spindle 42, 52 or the guide sleeve 35. The operator can use the operation panel or the external computer to store the NC program in the RAM of the NC device 80 in a rewritable manner.

[0084] Figure 2 The longitudinal section of the back spindle head 51 along the spindle centerline AX0 is schematically illustrated, and the actuator 69 located in a hidden position is also schematically illustrated. Figure 2 In the figure, the upper side from the spindle centerline AX0 shows the discharge member 70 in the closed state ST2 of the collet 61. Figure 2 The lower side from the spindle centerline AX0 shows the discharge member 70 moving to the right when the collet 61 is in the open state ST1. Figure 2 In addition, for the convenience of explanation, the direction in which the workpiece W0 as a product is discharged from the discharge component 70 ( Figure 2 The left side of the discharge member 70 is set as the front D1, and the direction in which the discharge member 70 retreats ( Figure 2The direction of the spindle centerline AX0 (to the right of the spindle) is defined as the rear direction D2, the direction away from the spindle centerline AX0 is defined as the outer direction, and the direction close to the spindle centerline AX0 is defined as the inner direction. Here, the front side, the rear side, the outer side, and the inner side are terms indicating positional relationships. The positional relationship represented by the front side or the rear side may also be a positional relationship deviating from the strict Z-axis direction, and the positional relationship represented by the outer side or the inner side may also be a positional relationship deviating from the direction strictly orthogonal to the spindle centerline AX0. Figure 3 The appearance of the clamping mechanism 6 a disposed outside the back spindle 52 is schematically illustrated. Figure 4 A longitudinal section of the clamping mechanism 6 a disposed outside the back spindle 52 is schematically illustrated. Figure 5 The appearance of the claw member 20 included in the clamping mechanism 6a is illustrated. Figure 6 The appearance of the claw holder 26 that tiltably holds the claw member 20 is illustrated. Figure 7 The appearance of the shifter 10 included in the clamping mechanism 6a is illustrated. Figure 8 The driving unit DR1 of the shifter 10 is schematically illustrated. Figures 9 to 12 The operation of the clamping mechanism 6a and its periphery is illustrated in a longitudinal cross-sectional view.

[0085] In addition, in order to make it easier to understand, Figure 2 , 4 In the cross-sectional views shown, there are portions where hatching is omitted.

[0086] The back spindle table 51 is provided with a back spindle 52 having a holding portion 60 for the workpiece W0 processed from the front, a support portion 53 of the back spindle 52, a built-in motor 55 for rotating the back spindle 52, an opening and closing device 6 of the holding portion 60, and a discharge member 70 for the workpiece W0 as a product. The support portion 53 may be a portion integrated with the back spindle table 51 or may be an independent component provided on the back spindle table 51. Figure 2 The support portion 53 shown is divided into a front portion where the front bearing B1 is provided and a rear portion where the rear bearing B2 is provided. The front portion is integrated with the rear spindle block 51, and the rear portion is an independent component provided on the rear spindle block 51. Of course, the front portion may be an independent component, and the rear portion may be integrated with the rear spindle block 51. The discharge component 70 is a replacement part, and is sometimes changed to allow the workpiece W0, which is a product, to be directed to the rear spindle block 51. Figure 2 The products passing through the right side pass through the tube, etc.

[0087] The back spindle 52 has a through hole 52a through which the discharge component 70 passes in the Z-axis direction, and is rotatably supported on the support portion 53 of the back spindle table 51 via rolling bearings B1 and B2, and is driven by a motor 55 to rotate around the spindle center line AX0. The chuck sleeve 63 and the push sleeve 65 are inserted into the through hole 52a in the Z-axis direction. These sleeves 63 and 65 have holes that pass through along the spindle center line AX1, and the discharge component 70 is inserted in the Z-axis direction. The sleeves 63 and 65 rotate around the discharge component 70 together with the back spindle 52 around the spindle center line AX1.

[0088] A collet 61 and a cover member 62 are provided at the front portion of the back spindle 52 as a holding portion 60 for holding the workpiece W0. A tapered portion 61a that becomes thinner toward the rear is formed on the outer peripheral surface of the collet 61. Slits are formed at multiple locations (for example, three locations) of the tapered portion 61a. The cover member 62 is mounted on the front end portion of the back spindle 52 to hold the collet 61. If the tapered portion 61a of the collet 61 is pressed against the inverted tapered portion 63a of the chuck sleeve 63, the collet 61 holds the workpiece W0. If the force of the inverted tapered portion 63a pressing the tapered portion 61a is released, the collet 61 releases the workpiece W0. In this way, the holding portion 60 has a closed state ST2 for holding the workpiece W0 and an open state ST1 for releasing the workpiece W0, and rotates together with the back spindle 52. The workpiece W0 released from the collet 61 is moved forward by the advancement of the discharge member 70. Figure 2 The left side is discharged.

[0089] The front bearing B1 is arranged on the front side of the clamping mechanism 6 a , and the rear bearing B2 is arranged on the rear side of the built-in motor 55 . Figure 2 The bearings B1 and B2 shown are ball bearings, but roller bearings etc. may be used as the bearings B1 and B2. The inner rings of the bearings B1 and B2 are mounted on the outer periphery of the rear main shaft 52. The outer rings of the bearings B1 and B2 are mounted on the support portion 53.

[0090] like Figure 1 As shown, there is a structure such as a comb-shaped tool rest 31, a back processing tool rest 32, or a turret tool rest 33 in the direction from the back spindle head 51 toward the support stand 36 of the guide sleeve 35. Figure 2 The main body 51a of the back spindle stock 51 shown has a structure that is supported so as to be movable in the X-axis direction and the Z-axis direction relative to the base 2, and is only close to the guide sleeve 35 to a position that does not interfere with the structure such as the tool holder 30. In order to make the front part of the back spindle 52 close to the guide sleeve 35, a relatively slender extension part 51b is provided, and the extension part 51b makes the front part of the back spindle 52 longer, and the front part of the back spindle 52 is rotatably supported on the back spindle stock 51 within a range that does not interfere with the structure such as the tool holder 30.

[0091] Between the front bearing B1 and the rear bearing B2, an internal motor 55 for rotating the back spindle 52 is arranged on the rear side of the clamping mechanism 6a. The internal motor 55 has a stator 56 on the support part 53 side and a rotor 57 on the back spindle 52 side, so as to drive the back spindle 52 to rotate according to the timing controlled by the NC device 80. As a driving part for rotating the back spindle, it is also considered to transmit the rotational driving force of the external motor to the back spindle 52 via a belt, but there are cases where the rotation of the back spindle cannot follow the rotation of the motor due to the expansion and contraction of the belt, or the belt is worn or broken. By using the internal motor 55 in the driving part for driving the back spindle 52, there is no need for a belt that may be worn or broken, and the rotation tracking performance of the back spindle 52 is improved.

[0092] The opening and closing device 6 of the holding portion 60 includes a chuck sleeve 63, a collet opening spring 64, a pressing sleeve 65, a clamping mechanism 6a including a claw member 20 and a shifter 10, and a driving portion DR1 including a shift rod 68 and a collet opening and closing actuator 69. In addition, in the above-mentioned forms 6 and 7 of the present technology, the shifter 10 is an example of one component, and the claw member 20 is an example of another component.

[0093] The chuck sleeve 63 has an inverted tapered portion 63a on the inner circumferential surface of the front end portion, and is disposed on the outer side of the collet 61 centered on the spindle centerline AX0. The inverted tapered portion 63a moves farther away from the spindle centerline AX0 as it moves toward the front side along the tapered portion 61a of the collet 61. The chuck sleeve 63 can slide in the Z-axis direction. If it moves toward the front side, the tapered portion 61a of the collet 61 is locked inward (closed state ST2). If it moves toward the rear side, the locking of the tapered portion 61a of the collet 61 is released (open state ST1). The spring 64 is, for example, a coil spring, with the front end portion clamped to the collet 61 and the rear end portion clamped to the inner circumferential surface of the chuck sleeve 63 to apply a rearward force to the chuck sleeve 63. The front end portion of the push sleeve 65 abuts against the rear end portion of the chuck sleeve 63. As Figure 4 As shown, the rear end face 65b of the push sleeve 65 abuts against the contact portion 22b of the claw member 20. The push sleeve 65 can slide in the Z-axis direction, and moves forward when a driving force for moving forward is applied from the claw member 20, and moves backward when a force for moving backward is applied from the spring 64 when the driving force from the claw member 20 is released.

[0094] The clamping mechanism 6a is disposed between the front bearing B1 and the rear bearing B2 on the outside of the back spindle 52. The clamping mechanism 6a of this specific example has the following characteristics: it is an inner claw type in which a claw member 20 exists on the inner side of the shifter 10 centered on the spindle centerline AX0. The clamping mechanism 6a is located further forward than the built-in motor 55 in the Z-axis direction.

[0095] The claw member 20 included in the clamping mechanism 6a is arranged between the front bearing B1 and the rear bearing B2 on the outer side of the back spindle 52 centered on the spindle center line AX0, and rotates around the spindle center line AX0. Figure 4 As shown in FIG. 1 , the clamping mechanism 6a has claw members 20 at two locations across the spindle centerline AX0. The front end of the claw member 20 is a base end 22 whose distance from the spindle centerline AX0 does not substantially change, and the rear end of the claw member 20 is a movable end 21 whose distance from the spindle centerline AX0 changes. On the outer surface of the claw member 20 centered on the spindle centerline AX0, as shown in FIG. Figure 5 As shown, a recessed portion 20a recessed toward the spindle centerline AX0 is formed between the base end portion 22 and the movable end portion 21. The displacer 10 is arranged outside the claw member 20 in the recessed portion 20a.

[0096] The base end portion 22 of the claw member 20 has an insertion hole 22a for Figure 3 , 4 The claw pin 23 shown passes in the direction of the tilting center axis; and the contact portion 22b contacts the rear end face 65b of the push sleeve 65. The claw member 20 can tilt around the claw pin 23 passing through the insertion hole 22a. The contact portion 22b is located closer to the spindle center line AX0 than the insertion hole 22a, and is pushed backward by the rear end face 65b of the push sleeve 65 or pushes the rear end face 65b of the push sleeve 65 back forward.

[0097] The distance between the movable end portion 21 of the claw member 20 and the spindle center line AX0 changes in accordance with the tilting of the claw member 20. Figure 2 As shown below the spindle centerline AX0, when the contact portion 22b is pushed backward by the push sleeve 65 and the collet 61 is in the open state ST1, the claw member 20 is in the first posture PO1 where the movable end portion 21 is located relatively far from the spindle centerline AX0. Figure 2 As shown above the spindle center line AX0, when the contact portion 22b pushes the push sleeve 65 forward, the claw member 20 is in the second posture PO2 in which the movable end portion 21 is located relatively close to the spindle center line AX0, and the collet 61 is in the closed state ST2. That is, the claw member 20 has the first posture PO1 in which the movable end portion 21 is relatively far from the spindle center line AX0 and the collet 61 is in the open state ST1, and the second posture PO2 in which the movable end portion 21 is relatively close to the spindle center line AX0 and the collet 61 is in the closed state ST2.

[0098] A groove 25 is provided near the movable end 21 in the recess 20a of the claw member 20. The groove 25 allows the roller 15 of the shifter 10 to enter when the movable end 21 is relatively far from the spindle center line AX0 (the claw member 20 is in the first posture PO1) and the collet 61 is in the open state ST1. The direction of the groove 25 is a direction perpendicular to the spindle center line AX0. The roller 15 of the shifter 10 contacts the outer side surface of the claw member 20 centered on the spindle center line AX0 from the groove 25 to the movable end 21. The outer side surface of the movable end 21 is located outside the outer side surface of the recess 20a centered on the spindle center line AX0, and the claw member 20 can tilt around the insertion hole 22a of the base end 22. Therefore, when the position where the roller 15 contacts the claw member 20 changes from the groove 25 to the movable end 21, the movable end 21 approaches the spindle center line AX0 and the collet 61 is in the closed state ST2.

[0099] In order to support the claw member 20 in a tiltable manner, the clamping mechanism 6a has a Figure 6 The claw holder 26 shown. The claw holder 26 has a large diameter portion 26a at the front and a small diameter portion 26b in the range from the large diameter portion to the rear end. The claw holder 26 has a through hole 26c from the large diameter portion 26a to the small diameter portion 26b for the back spindle 52 to pass in the Z-axis direction. The small diameter portion 26b is formed with a slit 26d aligned with the position of each claw member 20. The shifter 10 is arranged on the outside of the small diameter portion 26b centered on the spindle center line AX0 so as to be slidable in the Z-axis direction, and the outer peripheral surface 26e of the small diameter portion 26b serves as a guide surface for the shifter 10. The large diameter portion 26a is provided with a retaining portion 27, and the retaining portion 27 is provided with a claw pin 23 of the claw member 20 along the center axis of the tilt so that it can be removably mounted. The retaining portion 27 is divided into two parts by a gap 27a into which the base end portion 22 of the claw member 20 enters. A recessed portion 27b is formed at a position of the large diameter portion 26a adjacent to each holding portion 27. Each holding portion 27 is located between the gap 27a and the recessed portion 27b. Each holding portion 27 has an insertion hole 27c formed therein that communicates from the recessed portion 27b to the gap 27a and allows the claw pin 23 to pass therethrough.

[0100] Based on the above, if the base end portion 22 of the claw member 20 is arranged in the gap 27a, the claw pin 23 is passed through the insertion holes 27c of the two holding portions 27 and the insertion holes 22a of the base end portion 22, and the stop rings 24 are installed at both ends of the claw pin 23 (refer to Figure 3 ), then the claw member 20 can be tiltably mounted on the claw holder 26. The claw holder 26 on which the claw member 20 is mounted rotates around the spindle centerline AX0.

[0101] The shifter 10 included in the clamping mechanism 6a can move in the Z-axis direction on the outside of the recessed portion 20a of the claw member 20 and the thin-diameter portion 26b of the claw holder 26 centered on the spindle centerline AX0, and can rotate around the spindle centerline AX0. The shifter 10 slides in the Z-axis direction within the range of the claw member 20 located between the front bearing B1 and the rear bearing B2, and is configured at a first position LO1 that causes the claw member 20 to be in a first posture PO1 and a second position LO2 that causes the claw member 20 to be in a second posture PO2. Because the shifter 10 as a whole overlaps with the claw member 20 in the Z-axis direction, the inner claw type clamping mechanism 6a of this specific example can be shorter in the Z-axis direction than the outer claw type clamping mechanism, and there is no problem as shown in FIG. Fig.13 , 14 As shown, the extension 22c has a weight, so it is lightweight.

[0102] The shifter 10 has a through hole 10a through which the claw holder 26 passes in the Z-axis direction. An outward groove 12 is provided on the outer surface 11 of the shifter 10. The outward groove 12 is centered around the spindle centerline AX0 and is provided with an insertion portion 68a (see Figure 8 ) to enter. Figure 3 , 8 As shown, the outward groove 12 has a front side surface 12a and a rear side surface 12b opposite to each other in the Z-axis direction, and has a bottom surface 12c between the front side surface 12a and the rear side surface 12b. Figures 9 to 12 The fixing portion of the inner ring of the shifter bearing B3 shown has a bottom surface 12c with a recessed portion 12d that is further lowered toward the main shaft centerline AX0.

[0103] At the rear of the shifter 10, as Figures 2 to 4 As shown, a roller 15 capable of rolling in the Z-axis direction is installed at the position where the shifter 10 contacts the claw member 20. Each roller 15 has a through hole 15a for a roller pin 16 (an example of an axis member) to pass in the direction of the rolling center axis AX3, and can roll around the roller pin 16 passing through the through hole 15a. A retaining portion 14 is provided in the shifter 10 to the rear of the outer groove 12, and the roller pin 16 along the center axis AX3 is removably mounted. Figure 3 , 7 As shown, the holding portion 14 is divided into two parts by a gap 14a for the roller 15 to enter. A recess 14b is formed at a position adjacent to each holding portion 14 at the rear of the shifter 10. Each holding portion 14 is located at a position sandwiched by the gap 14a and the recess 14b. A through hole 14c is formed in each holding portion 14, which communicates from the recess 14b to the gap 14a and allows the roller pin 16 to pass through.

[0104] According to the above, if the roller 15 is arranged in the gap 14a and the roller pin 16 is passed through the insertion holes 14c of the two holding parts 14 and the insertion hole 15a of the roller 15, and the stopper rings 17 are installed at both ends of the roller pin 16, the roller 15 can be mounted on the shifter 10 so as to be rollable around the central axis AX3. In addition, if the stopper rings 17 are removed from both ends of the roller pin 16 and the roller pin 16 is pulled out from the insertion holes 14c and 15a, the roller 15 can be removed from the shifter 10.

[0105] like Figure 2 , 8 As shown, the driving unit DR1 of the shifter 10 includes a shift rod 68 provided with a shifter bearing B3 and an actuator 69.

[0106] like Figures 9 to 12 As shown, the drive unit DR1 has shift rods 68 at two locations across the spindle center line AX0. The two shift rods 68 have insertion portions 68a on mutually opposing surfaces near the front end 68c. Each insertion portion 68a enters the outward groove 12 of the shifter 10. If the base end 68b is driven by the actuator 69, each shift rod 68 slightly rotates around the fulcrum 68d, and the front end 68c moves approximately in the Z-axis direction. As a result, the shift rod 68 moves the shifter 10 in the Z-axis direction. The shifter 10 rotates around the spindle center line AX0, while the shift rod 68 does not rotate around the spindle center line AX0. Therefore, in the insertion portion 68a of the shift rod 68, as shown in FIG. Figures 9 to 12 As shown, a shifter bearing B3 capable of contacting the side surfaces 12a and 12b of the outward groove 12 is provided. The outer wheel of the shifter bearing B3 can rotate around the rotation axis AX4 intersecting the main shaft center line AX0, and the outer wheel can contact the side surfaces 12a and 12b of the outward groove 12. The shift rod 68 can be arranged in a manner that the outer wheel of the shifter bearing B3 is separated from both the front side surface 12a and the rear side surface 12b. That is, when the outer wheel of the shifter bearing B3 contacts the side surfaces 12a and 12b of the outward groove 12, it contacts only one of the front side surface 12a and the rear side surface 12b.

[0107] The actuator 69 includes a cylinder 69a and a piston 69b. The piston 69b protrudes from the cylinder 69a and is connected to the base end 68b of the shift rod 68 so that the front end can rotate. The shift rod 68 is driven according to the control of the NC device 80. The actuator 69 of this specific example is an electric actuator having an electric cylinder, but the cylinder 69a may also use an air cylinder, a hydraulic cylinder, or the like.

[0108] In addition, the shifter bearing also has a rolling bearing, which is a rolling bearing that allows the inner wheel that can rotate around the main shaft center line to enter the outward groove and contact the shifter. This rolling bearing is called a coaxial shifter bearing. The coaxial shifter bearing is arranged on the outside of the shifter with the main shaft center line as the center, so the diameter becomes larger. The outer wheel of the shifter bearing B3 in this specific example can rotate around the rotation axis AX4 that intersects the main shaft center line AX0. This shifter bearing B3 is called an opposing configuration type shifter bearing. The opposing configuration type shifter bearing B3 is smaller and cheaper than the coaxial shifter bearing. However, if the small shifter bearing B3 is in continuous contact with the side surfaces 12a and 12b of the outward groove 12 of the shifter 10, then when the back main shaft 52 rotates around the main shaft center line AX0, the shifter bearing B3 rotates faster than the back main shaft 52, and becomes easily consumed due to heat, etc.

[0109] Therefore, after the drive unit DR1 moves the shifter 10 in the Z-axis direction, the shifter bearing B3 is separated from the side surfaces 12a and 12b of the outer groove 12. In this way, the drive unit DR1 that drives the shift rod 68 can be realized by, for example, the operation of the actuator 69 under the control of the NC device 80. In this case, the drive unit DR1 includes the NC device 80. Figure 2 , 8 1 to 12, an operation example of the driving unit DR1 is described.

[0110] First, if Fig. 9 As shown, the shifter 10 is located at the first position LO1 on the front side, the movable end 21 is relatively far from the spindle center line AX0, the claw member 20 is in the first posture PO1, and the collet 61 is in the open state ST1 (refer to Figure 2 ), the shifter bearing B3 is located from the two side surfaces 12a, 12b of the outward groove 12 of the shifter 10 ( Figure 8 When the collet 61 is locked to hold the workpiece W0, the NC device 80 first drives the shift rod 68 so that the insertion portion 68a of the shift rod 68 moves backward. At this time, the piston 69b extending from the cylinder 69a moves forward, and the front end 68c of the shift rod 68 moves backward. As a result, the outer wheel of the shifter bearing B3 contacts the rear side surface 12b of the outward groove 12, as shown in FIG. Fig.10 As shown, the shifter 10 is moved to the second position LO2 at the rear side by the movement of the shift rod 68. As a result, the roller 15 of the shifter 10 rolls from the groove 25 to the movable end 21 with the central axis AX3 as the center, and the movable end 21 approaches the spindle center line AX0, so that the claw member 20 is in the second posture PO2, and the contact portion 22b of the claw member 20 pushes the chuck sleeve 63 forward via the pressing sleeve 65 (see Figure 2). When the chuck sleeve 63 moves forward, the reverse tapered portion 63a presses the tapered portion 61a toward the spindle centerline AX0, so that the collet 61 is locked and enters the closed state ST2.

[0111] Then, the NC device 80 causes the actuator 69 to drive the shift rod 68 so that the shifter bearing B3 is separated from the rear side surface 12b within a range that does not contact the front side surface 12a of the outward groove 12. At this time, the piston 69b extending from the cylinder 69a moves slightly backward, and the front end 68c of the shift rod 68 moves slightly forward. Fig.11 As shown, the shifter 10 reaches the second position LO2, and the shifter bearing B3 is separated from both side surfaces 12a and 12b of the outward groove 12. Therefore, even if the shifter 10 rotates at high speed around the main shaft centerline AX0, the shifter bearing B3 does not rotate at high speed.

[0112] When the collet 61 is opened to release the workpiece W0, the NC device 80 first drives the shift rod 68 so that the insertion portion 68a of the shift rod 68 moves forward. At this time, the piston 69b extending from the cylinder 69a moves backward, and the front end 68c of the shift rod 68 moves forward. As a result, the outer wheel of the shifter bearing B3 contacts the front side surface 12a of the outward groove 12, as shown in FIG. Fig.12 As shown, the shifter 10 is moved to the first position LO1 on the front side by the movement of the shift rod 68. As a result, the roller 15 of the shifter 10 rolls from the movable end 21 to the groove 25 around the central axis AX3, and the collet spring 64 for opening the collet pushes the push sleeve 65 backward via the collet sleeve 63 (see Figure 2 ), the movable end portion 21 moves away from the spindle center line AX0, and the claw member 20 is in the first posture PO1. If the chuck sleeve 63 moves backward, the force of the reverse tapered portion 63a pressing the tapered portion 61a toward the spindle center line AX0 is weakened, and the collet 61 is released to become the open state ST1.

[0113] Then, the NC device 80 causes the actuator 69 to drive the shift rod 68 so that the shifter bearing B3 is spaced from the front side surface 12a within a range that does not contact the rear side surface 12b of the outward groove 12. At this time, the piston 69b extending from the cylinder 69a moves slightly forward, and the front end 68c of the shift rod 68 moves slightly backward. Fig. 9 As shown, the shifter 10 reaches the first position LO1 and the shifter bearing B3 is separated from both side surfaces 12a and 12b of the outward groove 12. Therefore, even if the shifter 10 rotates at high speed about the main shaft centerline AX0, the shifter bearing B3 does not rotate at high speed.

[0114] As described above, the opposed-type shifter bearing B3 contacts the front side surface 12a or the rear side surface 12b in the outward groove 12 only when the state of the collet 61 is switched between the open state ST1 and the closed state ST2. In the case of a coaxial shifter bearing, the shifter bearing B3 rotates in accordance with the rotation of the shifter centered on the main shaft center line, so the rotation of the shifter bearing B3 of this specific example can be reduced compared to the coaxial shifter bearing. As a result, the heat generation and even consumption of the shifter bearing B3 can be suppressed. Therefore, the lathe of this specific example can use a small and low-cost shifter bearing and extend the life of the shifter bearing.

[0115] (3) The effects and effects of the specific examples described:

[0116] like Figure 1 As shown, there is a structure such as a tool holder 30 in front of the back spindle 51. Figure 2 The main body 51a of the back spindle block 51 shown is only close to the guide sleeve 35 to a position where it does not interfere with the structure such as the tool holder 30. In the case where the front part of the back spindle 52 is simply extended and supported by the relatively slender extension 51b of the back spindle block 51, the inner space of the extension 51b in the Z-axis direction increases. Fig.13 , 14 The outer claw type clamping mechanism 6b shown is long in the Z-axis direction. Therefore, if there is no intermediate bearing between the clamping mechanism 6b and the built-in motor, the back spindle 52 cannot be rotated at high speed, and therefore cannot enter between the front bearing B1 and the rear bearing B2. In the case of using an intermediate bearing, although the back spindle 52 can be rotated at high speed, the structure of the back spindle base 51 becomes complicated, and the front side of the back spindle 52 becomes too long. In addition, the clamping mechanism 6b is arranged further behind the rear bearing B2, which is disadvantageous for the high-speed rotation of the back spindle 52.

[0117] On the other hand, Figures 2 to 4 In the clamping mechanism 6a shown in FIGS. 9 to 12, a shifter 10 that can move in the Z-axis direction is arranged outside the claw member 20 located outside the back spindle 52. As a result, the inner-claw type clamping mechanism 6a of this specific example can be shorter in the Z-axis direction than the outer-claw type clamping mechanism 6b, and even without an intermediate bearing, it can be arranged between the front bearing B1 and the rear bearing B2 where the built-in motor 55 exists, so that the back spindle 52 can be rotated at a high speed. In the case where the front part of the back spindle 52 must be lengthened, the clamping mechanism 6a can be arranged in the space on the front side of the lengthened back spindle 52, and the back side of the back spindle 52 can be shortened. In addition, because the diameter of the clamping mechanism 6a can be smaller than the diameter of the built-in motor 55, it is easy to put the clamping mechanism 6a in the space on the front side of the back spindle base 51 that is lengthened in order to avoid interference with structures such as the tool holder 30.

[0118] As described above, this specific example can shorten the back spindle 52 in the Z-axis direction. Furthermore, the distance from the collet 61 located in front of the back spindle 52 to the clamping mechanism 6a is shortened, so this specific example can simplify the structure of the opening and closing device 6 of the collet 61.

[0119] Furthermore, a roller 15 capable of rolling in the Z-axis direction is installed on the shifter 10 at a position where the shifter 10 contacts the claw member 20, so that when the collet 61 is opened and closed, the roller 15 rolls in the Z-axis direction. As a result, the friction between the shifter 10 and the claw member 20 is reduced, and the load on the actuator 69 is reduced. In addition, although the roller 15 and the claw member 20 that contact each other gradually wear, the wear of the roller 15 and the claw member 20 is small. Furthermore, the operation of extracting the entire shifter that has been around the back spindle 52 from the back spindle 52 and installing a new one around the back spindle 52 takes time, but in this specific example, even if the roller 15 needs to be replaced, the entire shifter does not need to be replaced, so the replacement operation takes less time. In addition, if the roller pin 16 is removed from the retaining portion 14 of the shifter 10, the roller 15 can be taken out from the shifter 10 to the outside of the radial direction intersecting the spindle centerline AX0. After that, if the roller pin 16 passing through the insertion hole 15a of the roller 15 is mounted on the holding portion 14 of the shifter 10, the roller 15 is replaced, so it is easy to replace the roller 15. The claw member 20 does not go around the back main shaft 52, so it is easy to replace. Therefore, this specific example can make the maintenance of the clamping mechanism easy.

[0120] Here, when using the opposed displacer bearings B3, in order to suppress the consumption of the displacer bearings B3, after the displacer 10 is moved in the Z-axis direction, the displacer bearings B3 must be separated from the side surfaces 12a and 12b of the outward groove 12. Fig.11 As shown in FIG. 1 , when the roller 15 of the shifter 10 at the second position LO2 on the rear side presses the movable end 21 of the claw member 20 toward the spindle centerline AX0, the collet 61 is in the closed state ST2 holding the workpiece W0, so a strong force is applied to the roller 15 from the movable end 21. Therefore, even if the shifter bearing B3 is separated from the side surfaces 12a and 12b of the outward groove 12, the shifter 10 will not move in the Z-axis direction. However, if Fig. 9As shown, when the roller 15 of the shifter 10 located at the first position LO1 on the front side enters the groove 25 of the claw member 20, the collet 61 is in the open state ST1 to release the workpiece W0. At this time, only a weak force from the spring 64 for opening the collet is applied to the roller 15 from the claw member 20, so if there is no groove 25, the shifter 10 moves in the Z-axis direction, and there is a possibility that the shifter bearing B3 contacts the side surfaces 12a and 12b of the outward groove 12. The roller 15 of the shifter 10 of this specific example enters the groove 25 of the claw member 20 when the collet 61 is in the open state ST1, so the shifter bearing B3 maintains a state of being separated from the side surfaces 12a and 12b of the outward groove 12 of the shifter 10. Therefore, this specific example can extend the life of the shifter bearing.

[0121] (4) Variations:

[0122] The present invention contemplates various variations.

[0123] For example, the lathe to which the present technology can be applied is not limited to a mobile spindle type lathe, and may be a fixed spindle type lathe in which the main spindle does not move.

[0124] The spindle to which the present technology can be applied is not limited to the sub-spindle, but may be the main spindle.

[0125] The number of claw members of the clamping mechanism is not limited to two, and may be three or more.

[0126] In the above-mentioned aspects 1 to 5 of the present technology, the shifter bearing may be a coaxial type shifter bearing centered on the main shaft center line, and the groove 25 may not exist in the claw member 20 .

[0127] In the above-mentioned aspects 1 to 3 of the present technology, the roller 15 may not be present in the shifter 10 .

[0128] In the above-mentioned aspects 1 to 3, 6, and 7 of the present technology, a roller that can roll in the Z-axis direction may be mounted on the claw member at a position where the shifter and the claw member contact each other.

[0129] The clamping mechanism in the above-mentioned aspects 4 to 7 of the present technology can be arranged further rearward than the rear bearing B2, and may be an outer claw type clamping mechanism.

[0130] Fig.13 , 14 The longitudinal section of the outer claw type clamping mechanism 6b and its surroundings arranged behind the rear side bearing B2 (not shown) is shown as an example included in the above-mentioned forms 4 to 7 of the present technology. Here, Fig.13 The shifter 10 is shown in the second position LO2 on the rear side, the claw member 20 is in the second posture PO2, and the collet 61 (not shown) is in the closed state ST2. Fig.14The shifter 10 is shown in the first position LO1 on the front side, the claw member 20 is in the first posture PO1, and the collet 61 (not shown) is in the open state ST1.

[0131] Fig.13 , 14 The shifter 10 shown is a shape that goes around the back spindle 52 with the spindle center line AX0 as the center, and contacts a plurality of claw members 20. In the shifter 10, a roller 15 that can roll in the Z-axis direction is removably mounted at a position that contacts the claw member 20, further back than the outward groove into which the shifter bearing B3 enters. The claw member 20 has a movable end 21 that protrudes forward, and an extension 22c that extends back from the claw pin 23, and can tilt in a direction in which the distance from the spindle center line AX0 to the movable end 21 changes. In the claw member 20, a groove 25 into which the roller 15 enters is formed near the movable end 21 when the collet 61 is in the open state ST1.

[0132] When the collet 61 in the closed state ST2 is opened, the shifter bearing B3 is shifted from Fig.13 The shift rod 68 is driven to move forward in the state shown, and the shifter 10 pushed against the shifter bearing B3 moves forward. Then, the roller 15 of the shifter 10 rolls toward the movable end 21 to the groove 25 with the central axis AX3 as the center, and the collet spring 64 is opened to push the push sleeve 65 backward through the collet sleeve 63 (see Figure 2 ). If the push sleeve 65 is pushed backward, the movable end 21 approaches the spindle center line AX0 and the claw member 20 is in the first posture PO1. If the chuck sleeve 63 moves backward, the collet 61 is loosened and becomes the open state ST1. This state is shown in Fig.14 middle.

[0133] Here, even if the shifter rod 68 is driven in a manner that the shifter bearing B3 is separated from both sides of the outward groove of the shifter 10, the roller 15 of the shifter 10 enters the groove 25 of the claw member 20, so that the shifter bearing B3 is maintained in a state of being separated from both sides of the outward groove of the shifter 10. Therefore, even if the shifter 10 rotates at a high speed around the main shaft center line AX0, the shifter bearing B3 does not rotate at a high speed, and the life of the shifter bearing B3 is extended.

[0134] Fig.15 , 16 The longitudinal section of the inner claw type clamping mechanism 6c and its surroundings disposed between the bearings B1 and B2 (not shown) is shown as an example included in the above-mentioned aspects 1 to 3, 6, and 7 of the present technology. Fig.15 The shifter 10 is shown in the second position LO2 on the rear side, the claw member 20 is in the second posture PO2, and the collet 61 (not shown) is in the closed state ST2. Fig.16 The shifter 10 is in the first position LO1 on the front side, the claw member 20 is in the first posture PO1, and the collet 61 (not shown) is in the open state ST1. In the above-mentioned sixth and seventh aspects of the present technology, the claw member 20 is an example of one member, and the shifter 10 is an example of the other member.

[0135] Fig.15 , 16 In each of the claw members 20 shown, a roller 15 capable of rolling in the Z-axis direction is removably mounted near the movable end 21 at a position in contact with the shifter 10. In the shifter 10, a groove 25 is formed behind the outward groove into which the shifter bearing B3 enters, into which the roller 15 enters when the collet 61 is in the open state ST1.

[0136] When the collet 61 in the closed state ST2 is opened, the shifter bearing B3 is shifted from Fig.15 The shift rod 68 is driven to move forward in the state shown, and the shifter 10 pushed against the shifter bearing B3 moves forward. Then, the roller 15 of the claw member 20 rolls to the groove 25 toward the rear end of the shifter 10 with the central axis AX3 as the center, and the collet spring 64 is opened to push the push sleeve 65 backward through the collet sleeve 63 (see Figure 2 ). If the push sleeve 65 is pushed backward, the movable end 21 moves away from the spindle center line AX0 and the claw member 20 is in the first posture PO1. If the chuck sleeve 63 moves backward, the collet 61 is loosened and becomes the open state ST1. This state is shown in Fig.16 middle.

[0137] Here, even if the shifter rod 68 is driven in a manner that the shifter bearing B3 is separated from both sides of the outward groove of the shifter 10, the roller 15 of the claw member 20 enters the groove 25 of the shifter 10, so that the shifter bearing B3 is maintained in a state of being separated from both sides of the outward groove of the shifter 10. Therefore, even if the shifter 10 rotates at a high speed around the main shaft center line AX0, the shifter bearing B3 does not rotate at a high speed, and the life of the shifter bearing B3 is extended.

[0138] (5) Summary:

[0139] As described above, according to the present invention, various forms can provide a lathe or other technology that can shorten the spindle in the spindle centerline direction, make the maintenance of the clamping mechanism easier, or extend the life of the shifter bearing. Of course, even if the technology is composed only of the constituent elements of the independent claim, it can also obtain the above basic functions and effects.

[0140] In addition, it is also possible to implement a configuration in which the configurations disclosed in the above examples are replaced with each other or are modified and combined, a configuration in which the known technology and the configurations disclosed in the above examples are replaced with each other or are modified and combined, etc. The present invention also includes these configurations, etc.

[0141] [Explanation of Symbols]

[0142] 1 Lathe

[0143] 6 Opening and closing device

[0144] 6a, 6b, 6c Clamping mechanism

[0145] 10 Shifter

[0146] 10a Through hole

[0147] 11 External surface

[0148] 12 Outward groove

[0149] 12a Front side

[0150] 12b Rear side

[0151] 14. Holding unit

[0152] 14a Gap

[0153] 14b recess

[0154] 14c Through hole

[0155] 15 Roller

[0156] 15a Through hole

[0157] 16 Roller pin (example of shaft component)

[0158] 20 claw parts

[0159] 20a recess

[0160] 21 Movable end

[0161] 22 Base end

[0162] 23 Claw pin

[0163] 25 slots

[0164] 26 claw holder

[0165] 27. Maintaining part

[0166] 30 Tool holder

[0167] 35 Guide bushing

[0168] 36 Support table

[0169] 41 Front spindle table (Example of front spindle table)

[0170] 42 Positive spindle (Example of positive spindle)

[0171] 51 Rear spindle table (Example of sub-spindle table)

[0172] 51a Main body

[0173] 51b Extension

[0174] 52 Back spindle (Example of a secondary spindle)

[0175] 52a Through hole

[0176] 53 Support

[0177] 55 Built-in motor

[0178] 56 Stator

[0179] 57 Rotor

[0180] 60 Holding part

[0181] 61 Collet

[0182] 62 Cover parts

[0183] 63 Collet Sleeve

[0184] 64 Spring

[0185] 65 Push sleeve

[0186] 68 Shift lever

[0187] 68a Insertion

[0188] 69 Actuator

[0189] 80 NC device

[0190] AX0, AX1 Spindle centerline

[0191] AX3 Rolling axis

[0192] AX4 Rotary Axis

[0193] B1 front bearing

[0194] B2 rear bearing

[0195] B3 shifter bearing

[0196] D1 Front

[0197] D2 rear

[0198] DR1 drive unit

[0199] LO1 First Position

[0200] LO2 Second position

[0201] PO1 First Pose

[0202] PO2 Second position

[0203] ST1 Open state

[0204] ST2 Closed state

[0205] W0, W1 workpieces.

Claims

1. A lathe comprising: a spindle, a holding portion having a closed state for holding a workpiece and an open state for releasing the workpiece provided at the front, and capable of rotating about a center line of the spindle; a support portion that rotatably supports the main shaft via a front bearing and a rear bearing; and a built-in motor disposed between the front bearing and the rear bearing and causing the main shaft to rotate; and An opening and closing device, which opens and closes the holding portion; The opening and closing device comprises: a claw member, which is arranged between the front bearing and the rear bearing on the outside of the spindle, is tiltable, and has a movable end portion, the distance of which from the center line of the spindle changes between a first posture in which the retaining portion is in an open state and a second posture in which the retaining portion is in a closed state; and a shifter capable of moving outside the claw member in the direction of the spindle centerline, and arranged at a first position where the claw member is in a first posture and a second position where the claw member is in a second posture; in In the direction of the spindle centerline, the claw member and the shifter are located further forward than the built-in motor; The claw member includes a base end portion having an insertion hole for inserting a claw pin, and the claw member has a recess and a groove formed on an outer peripheral surface of the claw member between the base end portion and the movable end portion; The concave portion and the groove are divided by a convex portion therebetween; The groove is located between the recess and the movable end portion and is narrower than the recess; The displacer is located in the recessed portion and the groove of the claw member in the first posture, and at least a portion of the displacer is located on the movable end portion of the claw member in the second posture.

2. The lathe according to claim 1, wherein the lathe comprises: A main spindle table is provided with a main spindle for holding the workpiece; a tool holder for machining a workpiece held on the positive spindle; and The sub-spindle table is provided with a sub-spindle as the main spindle, which is opposed to the main spindle and receives the workpiece from the main spindle.

Images