JP5985354B2 - Tailstock and machine tool - Google Patents

Description

  The present invention relates to a tailstock or the like that presses and supports the end surface of the other end portion of the workpiece with a center in a state where one end portion of the workpiece is gripped by a spindle of a machine tool such as a lathe.

  Conventionally, various developments have been made on tailstocks used in machine tools such as lathes, and there is one disclosed in Patent Document 1 as a prior art of tailstocks. The configuration of the tailstock according to the prior art will be briefly described as follows.

  On the lathe bed, a tailstock block (tailstock main body) is provided so as to face the headstock of the lathe in the Z-axis direction and be movable in the Z-axis direction. In addition, the tailstock block is provided with a movable sleeve that can move in the Z-axis direction. The movable sleeve is taper-fitted with the base end of the center on the headstock side (one side in the Z-axis direction). It has a center holding part that can be combined. Further, a sleeve hydraulic cylinder for moving the movable sleeve in the Z-axis direction is provided on the opposite side (the other side in the Z-axis direction) of the tailstock block side, and one end of the sleeve hydraulic cylinder is provided. From the side to the other end side, an insertion hole is formed (penetrated) along the Z-axis direction, and the insertion hole communicates with the movable sleeve.

  Therefore, after gripping one end of the workpiece by the spindle and taper-fitting the center of the center to the center holding part of the movable sleeve, the tailstock block is moved to the spindle base by driving an appropriate block electric motor. . Thereby, a center can be made to approach the end surface of the other end part of a work.

  Subsequently, the movable sleeve is moved to the headstock side by driving the sleeve hydraulic cylinder. Thereby, the end surface of the other end part of the workpiece can be pressed and supported by the center, and preparation for cutting by the lathe is completed.

  After cutting the workpiece, the movable sleeve is moved to the opposite side of the headstock side by driving the hydraulic cylinder for sleeves, and the tailstock block is moved to the side of the headstock side by driving an appropriate block electric motor. Move to the other side. As a result, the center can be separated from the end face of the other end of the machined workpiece, the gripping state of the spindle can be released, and the machined workpiece can be taken out from the spindle.

  Although not described in Patent Document 1, when removing the center from the center holding portion of the movable sleeve, an appropriate push rod is used, and the side of the sleeve hydraulic cylinder (side in the Z-axis direction), in other words, The push rod is inserted through the insertion hole of the sleeve hydraulic cylinder from the side of the tailstock. Thus, the end surface of the base end portion of the center can be pressed toward the headstock by the push rod, the taper fitting state between the center base portion and the center holding portion of the movable sleeve is released, and the center is moved to the center of the movable sleeve. It can be removed from the holding part.

Japanese Utility Model Publication No. 7-24503

  By the way, as described above, when removing the center from the center holding portion of the movable sleeve, the work using the push rod must be performed on the side of the tailstock, and at least the push rod as a work space for removing the center is required. A space of a size corresponding to the length is required. Therefore, when installing the lathe in the factory, in addition to the installation space for the lathe, it is necessary to secure a work space for removing the center of a size corresponding to the length of the push bar on the side of the tailstock. There is a problem that it is difficult to make effective use of factory space.

  Therefore, an object of the present invention is to provide a tailstock having a novel configuration that can solve the above-described problems.

  A first feature of the present invention is a tailstock that presses and supports the end surface of the other end of the work with a center in a state where the one end of the work is gripped by the spindle of the machine tool. A tailstock block (tailstock body) provided opposite to the spindle of the machine in the Z-axis direction and movable in the Z-axis direction relative to the spindle stock, and a Z A center holding portion that is provided so as to be movable in the axial direction and that can be taper-fitted with the base end portion of the center on the head stock side (one side in the Z-axis direction) and removes the center from the center holding portion A movable sleeve configured to move in the Z-axis direction within a stroke (movement range) set in advance in a normal case other than the case and the tailstock block are provided, and the movable sleeve is moved in the Z-axis direction. Actuator for moving sleeve An eta, and is provided in the movable sleeve, extends in the Z-axis direction, and is movable in the Z-axis direction integrally with the movable sleeve in the normal case. A pressing rod for pushing the center to the headstock side when removing from the center holding portion, and the movable sleeve exceeds the stroke (stroke end of the stroke) and is opposite to the headstock side ( When moving to the other side in the Z-axis direction, the pressing rod moves toward the headstock relative to the movable sleeve, and presses the end surface of the base end portion of the center toward the headstock. The summary is as follows.

  In the specification and claims of the present application, the “Z-axis direction” refers to a direction parallel to the axis of the main shaft. Further, “provided” means that it is indirectly provided through another member in addition to being directly provided. Furthermore, “provided so as to face the headstock in the Z-axis direction” includes being provided so as to face the headstock in the Z-axis direction when cutting or grinding the workpiece. I mean.

  According to the first feature, after the one end portion of the workpiece is gripped by the spindle and the base portion of the center is taper-fitted to the center holding portion of the movable sleeve, the tailstock block is moved to the spindle head side. Move. Thereby, the said center can be made to approach the end surface of the other end part of a workpiece | work.

  Subsequently, the movable sleeve is moved toward the headstock within the stroke by driving the sleeve actuator. Thereby, the end surface of the other end part of the workpiece can be pressed and supported by the center, and preparation for cutting or grinding by the machine tool is completed.

  After cutting or grinding the workpiece, the movable sleeve is moved to the opposite side of the headstock within the stroke by driving the sleeve actuator, and the tailstock block is moved to the headstock. Move to the opposite side. As a result, the center can be separated from the end face of the other end of the machined workpiece, the gripping state of the spindle can be released, and the machined workpiece can be taken out from the spindle.

  When the center is removed from the center holding portion of the movable sleeve, the movable sleeve is moved to the opposite side of the headstock side over the stroke by driving the sleeve actuator. As a result, the pressing rod moves relative to the movable sleeve toward the headstock side, and the end surface of the base end portion of the center can be pressed toward the headstock side. The center can be removed by releasing the taper fitting state of the movable sleeve with the center holding portion. In other words, the taper fitting state between the base portion of the center and the center holding portion of the movable sleeve is performed without performing work using a push rod on the side of the tailstock (the other side in the Z-axis direction). The center can be removed from the center holding portion of the movable sleeve by releasing.

  The gist of a second feature of the present invention is that a machine tool that performs cutting or grinding on a workpiece includes a tailstock having the first feature.

  According to the 2nd characteristic, there exists the same effect as the 1st characteristic.

  According to the present invention, since the center can be removed from the center holding portion of the movable sleeve without performing a work using a push bar on the side of the tailstock, the machine tool is installed in a factory. In this case, it is not necessary to secure a work space for removing the center on the side of the tailstock, and the factory space can be used effectively.

FIG. 1 is a front cross-sectional view showing a tailstock according to the first embodiment of the present invention. FIG. 2A is an enlarged view of the arrow IIA in FIG. 1 and shows a state in which the pressing rod is positioned at a reference relative position, and FIG. The state which has pressed the end surface of the base end part to the headstock side is shown. FIG. 3 is a schematic front view of the machine tool according to the first embodiment of the present invention. FIG. 4 is a front sectional view showing a tailstock according to the second embodiment of the present invention. FIG. 5A is an enlarged view of the arrow VA in FIG. 4 and shows a state in which the end surface of the distal end portion of the first operating rod is in contact with the stopper ring, and FIG. The state where the pressing rod presses the end surface of the base end portion of the center toward the headstock side is shown. FIG. 6 is a schematic front view of a machine tool according to the second embodiment of the present invention.

(First embodiment)
A first embodiment of the present invention will be described with reference to FIGS.

  As shown in FIG. 3, the machine tool 1 according to the first embodiment of the present invention performs cutting or grinding on a workpiece W, and includes a bed 3 as a base. A spindle stock 5 is provided on one side of the bed 3 in the Z-axis direction, and a spindle 7 is provided on the spindle stock 5 so as to be rotatable around its axis. Has a chuck 9 for gripping one end of the workpiece W on the tip side. Further, the spindle stock 5 is provided with a spindle electric motor 11 for rotating the spindle 7 around its axis. Although not shown, on one side of the headstock 5 in the bed 3 in the X-axis direction, a processing head such as a turret tool post for performing cutting or grinding is provided in the X-axis direction, the Y-axis direction, and It is provided so as to be movable in the Z-axis direction.

  A tailstock 13 is provided on the other side of the bed 3 in the Z-axis direction so as to face the headstock 5 in the Z-axis direction. The tailstock 13 is connected to one end of the workpiece W by the chuck 9 of the spindle 7. The center 15 presses and supports the end surface (center hole formed in the end surface) of the other end of the work W with the center 15 in a state where the portion is gripped. And the specific structure of the tailstock 13 is as follows.

  As shown in FIGS. 1 and 3, on the other side of the bed 3 in the Z-axis direction, a tailstock block (tailstock body) 17 is opposed to the headstock 5 in the Z-axis direction and a plurality (only one) is provided. A guide hole 21 is formed (through-formed) along the Z-axis direction in the tailstock block 17. A block electric motor 23 for moving the tailstock block 17 in the Z-axis direction is provided at an appropriate position of the bed 3.

  As shown in FIGS. 1 and 2A, a guide sleeve 21 of the tailstock block 17 is provided with a movable sleeve 25 extending in the Z-axis direction so as to be movable in the Z-axis direction. The movable sleeve 25 is provided with a cylindrical movable sleeve main body 27, and is provided concentrically with the movable sleeve main body 27 on the main shaft base 5 side (one side in the Z-axis direction) within the movable sleeve main body 27. A cylindrical center holder 29 as a center holding portion capable of fitting and holding the end portion, and a tip end portion (the other end portion in the Z-axis direction) of the center holder 29 is provided concentrically with the movable sleeve body 27. And a stepped support pipe 31. Further, the movable sleeve 25 is configured to move in the Z-axis direction within a stroke (movement range) S set in advance in a normal case other than when the center 15 is removed from the center holder 29. If the movable sleeve 25 is provided in the tailstock block 17 so as to be movable in the Z-axis direction, the guide hole 21 may be omitted from the tailstock block 17.

  On the other side of the tailstock block 17 in the Z-axis direction, a sleeve electric motor 33 that moves the movable sleeve 25 in the Z-axis direction is provided via a pulley box 35. In the movable sleeve body 27, a ball screw 37 as a screw member extending in the Z-axis direction is provided concentrically with the movable sleeve body 27 (movable sleeve 25). The ball screw 37 is a main pulley. 39, a timing belt 41, and a driven pulley 43, which are linked to the output shaft of the sleeve electric motor 33. Further, the base end side (the other side in the Z-axis direction) of the ball screw 37 is rotatably supported by the tailstock block 17 via a radial bearing 45, and includes a main pulley 39, a timing belt 41, and a driven pulley. 43 is located in the pulley box 35. A nut member 47 screwed into the ball screw 37 is provided at the other end of the movable sleeve body 27 in the Z-axis direction. The ball screw 37 may be coupled to the output shaft of the sleeve electric motor 33 via a coupling (not shown) instead of the main pulley 39 or the like.

  In the support pipe 31, a stepped pressing rod 49 extending in the Z-axis direction is provided so as to be movable in the Z-axis direction via the key bolt 51 and the key groove 53 and non-rotatable. When the center 15 is removed from the center holder 29, the center 15 is pushed out toward the headstock 5 side. Further, a recess 55 is formed at the center of the end surface of the proximal end portion of the pressing rod 49 (the end surface on the other side in the Z-axis direction).

  As shown in FIG. 2A, in the support pipe 31, in the normal case, the pressure rod 49 is opposite to the headstock 5 side so as to be positioned at a reference relative position with respect to the support pipe 31 (movable sleeve 25). A spring 57 is provided as an urging member for urging to the side (the other side in the Z-axis direction). Here, the reference relative position is a relative position with respect to the support pipe 31 for maintaining a non-contact state between the end surface of the distal end portion of the pressing rod 49 and the end surface of the proximal end portion of the center 15. The relative position with respect to the support pipe 31 when the wall surface on one side in the Z-axis direction of the key groove 53 is brought into contact with the key bolt 51. In the normal case, the pressing rod 49 is positioned at a reference relative position with respect to the support pipe 31, so that the pressing rod 49 can move in the Z-axis direction integrally with the movable sleeve 25.

  A steel ball receiving member 59 is integrally provided at the tip of the ball screw 37, and the steel ball receiving member 59 is provided with a steel ball 61 that rotatably contacts the depression 55 of the pressing rod 49. ing. Instead of the steel ball receiving member 59 and the like provided at the tip of the ball screw 37, a thrust bearing (not shown) that rotatably contacts the end face of the proximal end of the pressing rod 49 may be provided. Absent.

  2B, the tailstock 13 is pressed by the ball screw 37 when the movable sleeve 25 moves beyond the stroke S (the stroke end of the stroke S) to the opposite side of the headstock 5 side. The movement of the rod 49 on the opposite side to the headstock 5 side with respect to the tailstock block 17 is restricted, and the pressing rod 49 resists the biasing force of the spring 57 and moves relative to the support pipe 31 from the reference relative position. It moves to the stage 5 side and is configured to press the end face of the base end portion of the center 15 toward the headstock 5 side.

  Then, the effect | action and effect of 1st Embodiment of this invention are demonstrated.

  After gripping one end portion of the workpiece W by the chuck 9 of the main shaft 7 and taperingly fitting the base portion of the center 15 to the center holder 29, the tailstock block 17 is moved to the main shaft base 5 side by driving of the block electric motor 23. Move. Thereby, the center 15 can be brought close to the end surface of the other end portion of the workpiece W.

  Subsequently, by rotating the ball screw 37 in the forward direction by driving the sleeve electric motor 33, the ball sleeve 37 and the nut member 47 are coupled together, and the movable sleeve 25 is moved toward the headstock 5 within the stroke S. Move. Thereby, the end surface of the other end part of the workpiece W can be pressed and supported by the center 15, and the preparation for cutting or grinding by the machine tool 1 is completed.

  After completing the preparation for cutting, etc., the machining head is rotated around the axis of the workpiece W integrally with the spindle 7 by driving the spindle electric motor 11, and the machining head is moved in the X axis direction, the Y axis direction, and the Z axis. Move in at least one of the directions. Thereby, cutting or grinding can be performed on the workpiece W.

  After the workpiece W is cut or ground, the ball screw 37 is rotated in the reverse direction by the drive of the sleeve electric motor 33, so that the ball screw 37 and the nut member 47 are coupled with each other. The sleeve 25 is moved in the stroke S to the opposite side of the headstock 5 side. Further, the tailstock block 17 is moved to the opposite side of the headstock 5 side by driving the block electric motor 23. Thereby, the center 15 can be separated from the end face of the other end of the processed workpiece W, the gripping state of the chuck 9 of the main shaft 7 can be released, and the processed workpiece W can be taken out from the main shaft 7. .

  When removing the center 15 from the center holder 29, the ball screw 37 is slightly rotated in the reverse direction by driving the sleeve electric motor 33, so that the movable sleeve 25 exceeds the stroke S and is opposite to the headstock 5 side. Move to. Thereby, the movement of the pressing rod 49 on the opposite side of the headstock 5 side with respect to the tailstock block 17 is restricted by the ball screw 37, and the pressing rod 49 is opposed to the movable sleeve 25 while resisting the urging force of the spring 57. Thus, the end face of the base end portion of the center 15 can be pressed toward the head stock 5 side by moving to the head stock 5 side, and the taper fitting state between the base portion of the center 15 and the center holder 29 is released, The center 15 can be removed. In other words, the taper between the base portion of the center 15 and the center holder 29 is not performed on the side of the tailstock 13 (the other side in the Z-axis direction) using the push rod (see the description of [Background Art]). The center 15 can be removed from the center holder 29 by releasing the fitted state.

  As described above, according to the first embodiment of the present invention, the center 15 can be detached from the center holder 29 without performing the work using the push rod on the side of the tailstock 13, so that the machine tool 1 is When installing in the factory, it is not necessary to secure a work space for removing the center 15 on the side of the tailstock 13, and the space in the factory can be used effectively.

(Second Embodiment)
A second embodiment of the present invention will be described with reference to FIGS.

  As shown in FIG. 6, the machine tool 63 according to the second embodiment of the present invention is similar to the machine tool 1 (see FIG. 5) according to the first embodiment of the present invention. A grinding work is performed, and a tailstock 65 having a configuration different from that of the tailstock 13 (see FIG. 1) is provided. Hereinafter, only the configuration different from the configuration of the machine tool 1 (the configuration of the tailstock 65) in the configuration of the machine tool 63 will be described. Of the plurality of components in the machine tool 63, those corresponding to the components in the machine tool 1 are denoted by the same reference numerals in the drawing.

  The tailstock 65 presses and supports the end surface (center hole formed in the end surface) of the other end of the workpiece W by the center 67 in a state where one end of the workpiece W is gripped by the chuck 9 of the main shaft 7. . And the specific structure of the tailstock 65 is as follows.

  As shown in FIGS. 4 and 6, on the other side of the bed 3 in the Z-axis direction, a tailstock block (tailstock body) 69 is opposed to the headstock 5 in the Z-axis direction and a plurality (only one) is provided. A guide hole 73 is formed (through-formed) along the Z-axis direction in the tailstock block 69. A block electric motor 75 for moving the tailstock block 69 in the Z-axis direction is provided at an appropriate position of the bed 3.

  As shown in FIGS. 4 and 5A, a movable sleeve 77 extending in the Z-axis direction is provided in the guide hole 73 of the tailstock block 69 so as to be movable in the Z-axis direction. 77 has a center holding portion 79 capable of being taper-fitted to the base end portion of the center 67 on the head stock 5 side (one side in the Z-axis direction). Further, the movable sleeve 77 is configured to move in the Z-axis direction within a preset stroke S in a normal case other than when the center 67 is removed from the center holding portion 79.

  A sleeve hydraulic cylinder 81 for moving the movable sleeve 77 in the Z-axis direction is integrally provided on the other side of the tailstock block 69 in the Z-axis direction. Details of the configuration of the sleeve hydraulic cylinder 81 are provided. The explanation is as follows.

  The sleeve hydraulic cylinder 81 includes a cylindrical cylinder main body 83 provided integrally with the tailstock block 69. The cylinder main body 83 has a ring-shaped cylinder cap 85 on the other side in the Z-axis direction. have. A first piston 87 is provided in the cylinder body 83 so as to be liquid-tightly slidable in the Z-axis direction. The first piston 87 in the cylinder body 83 is opposite to the headstock 5 side (Z-axis). On the other side of the direction, the second piston 89 is provided so as to be capable of liquid-tight sliding in the Z-axis direction. Although most of the cylinder main body 83 is configured by the same member as the tailstock block 69, the entire cylinder main body 83 may be configured by a member different from the tailstock block 69. Absent.

  A base end portion of a cylindrical first operating rod 91 extending in the Z-axis direction is integrally connected to the first piston 87, and a distal end portion of the first operating rod 91 is connected to the Z of the movable sleeve 77. It is integrally connected to the other end portion in the axial direction. Further, in the first operating rod 91, a second operating rod 93 extending in the Z-axis direction is penetratingly supported so as to be capable of liquid-tight sliding in the Z-axis direction relative to the first operating rod 91, The base end portion of the second operating rod 93 is integrally connected to the second piston 89. Further, a guide rod 95 extending in the Z-axis direction is pierced and supported in the cylinder cap 85 so as to be liquid-tightly slidable in the Z-axis direction. A base end portion of the guide rod 95 is integrated with the second piston 89. Connected.

  A first hydraulic chamber 97 is defined between the first piston 87 and the inner wall surface of the cylinder body 83 (an inner wall surface on one side in the Z-axis direction), and is formed on one side of the cylinder body 83 in the Z-axis direction. A first pressure oil port 99 is formed in communication with the first hydraulic chamber 97 to pressurize the first hydraulic chamber 97 and release the pressurized state. A second hydraulic chamber 101 is defined between the second piston 89 and the inner wall surface of the cylinder main body 83 (the other inner wall surface in the Z-axis direction). On the side, a second pressure oil port 103 for performing pressurization of the second hydraulic chamber 101 and release of the pressurized state is formed in communication with the second hydraulic chamber 101. Further, a third hydraulic chamber 105 is defined between the first piston 87 and the second piston 89, and the end surface of the tip of the guide rod 95 is pressurized and pressurized. A third pressure oil port 107 for releasing the state is formed in communication with the third hydraulic chamber 105.

  A pressing rod 109 extending in the Z-axis direction is provided in the movable sleeve 77 so as to be movable in the Z-axis direction. The pressing rod 109 is used when the center 67 is removed from the center holding portion 79 of the movable sleeve 77. This is for pushing the center 67 toward the headstock 5 side. Further, the proximal end portion of the pressing rod 109 is integrally connected to the distal end portion of the second operating rod 93. The pressing rod 109 is configured by the same member as the second operating rod 93, but may be configured by a member different from the second operating rod 93.

  As shown in FIG. 5A, the distal end side of the second operating rod 93 is a stopper member that restricts the movement of the first operating rod 91 relative to the second operating rod 93 toward the headstock 5 side. A stopper ring 111 is provided. Further, the tailstock 65 presses the third hydraulic chamber 105 to press the end surface of the first operating rod 91 in a normal case other than when the center 67 is removed from the center holding portion 79 of the movable sleeve 77. The stopper ring 111 is brought into contact with the end surface of the distal end portion of the pressing rod 109 and the end surface of the proximal end portion of the center 67 so as to maintain a non-contact state. Further, the pressing rod 109 can move in the Z-axis direction integrally with the movable sleeve 77 by maintaining the contact state between the end face of the tip of the first operating rod 91 and the stopper ring 111 in the normal case. It has become.

  Then, as shown in FIG. 5B, the tailstock 65 releases the pressurization state of the second hydraulic chamber 101 and the third hydraulic chamber 105 and pressurizes the first hydraulic chamber 97 to move the movable sleeve 77. Moves beyond the stroke S to the opposite side of the headstock 5 side (the other side in the Z-axis direction), the contact state between the end surface of the tip of the first operating rod and the stopper ring is released, and the pressing rod 109 is moved. It moves to the headstock 5 side relative to the movable sleeve 77 and is configured to press the end face of the base end portion of the center 67 to the headstock 5 side.

  Next, the operation and effect of the second embodiment of the present invention will be described.

  After gripping one end portion of the workpiece W by the chuck 9 of the main shaft 7 and taper-fitting the base portion of the center 67 to the center holding portion 79 of the movable sleeve 77, the pressurized state of the second hydraulic chamber 103 is released and the second pressure chamber 103 is released. While pressurizing the first hydraulic chamber 97 and the third hydraulic chamber 105, the tailstock block 69 is moved to the headstock 5 side by driving the block electric motor 75. Thereby, the center 67 can be brought close to the end surface of the other end portion of the workpiece W.

  Subsequently, the movable sleeve 77 is moved toward the headstock 5 within the stroke S by releasing the pressurization state of the first hydraulic chamber 97 and pressurizing the second hydraulic chamber 101 and the third hydraulic chamber 105. Thereby, the end surface of the other end part of the workpiece W can be pressed and supported by the center 67, and preparation for cutting or grinding by the machine tool 1 is completed.

  After completing the preparation for cutting, etc., the machining head is rotated around the axis of the workpiece W integrally with the spindle 7 by driving the spindle electric motor 11, and the machining head is moved in the X axis direction, the Y axis direction, and the Z axis. Move in at least one of the directions. Thereby, cutting or grinding can be performed on the workpiece W.

  After cutting or grinding the workpiece W, the pressurization state of the second hydraulic chamber 101 is released and the first hydraulic chamber 97 and the third hydraulic chamber 105 are pressurized, so that the movable sleeve 77 is stroked S. To the opposite side of the headstock 5 side. Further, the tailstock block 69 is moved to the opposite side of the headstock 5 side by driving the block electric motor 75. Thereby, the center 67 can be separated from the end face of the other end of the processed workpiece W, the gripping state of the chuck 9 of the main shaft 7 can be released, and the processed workpiece W can be taken out from the main shaft 7. .

  When the center 67 is removed from the center holding portion 79 of the movable sleeve 77, the movable sleeve 77 is released by releasing the pressurization state of the second hydraulic chamber 101 and the third hydraulic chamber 105 and pressurizing the first hydraulic chamber 97. Move over the stroke S to the opposite side of the headstock 5 side. As a result, the contact state between the end surface of the distal end portion of the first operating rod 91 and the stopper ring 111 is released, and the pressing rod 109 moves toward the headstock 5 relative to the movable sleeve 77, and the center 67. The end surface of the base end portion can be pressed toward the headstock 5, the taper fitting state between the base portion of the center 67 and the center holding portion 79 of the movable sleeve 77 can be released, and the center 67 can be removed. In other words, the taper fitting state between the base portion of the center 67 and the center holding portion 79 of the movable sleeve 77 is performed without performing the work using the push rod on the side of the tailstock 65 (the other side in the Z-axis direction). The center 67 can be removed from the center holding portion 79 of the movable sleeve 77 by releasing.

  As described above, according to the second embodiment of the present invention, the center 67 can be detached from the center holding portion 79 of the movable sleeve 77 without performing the work using the push rod on the side of the tailstock 65. When the machine tool 63 is installed in the factory, it is not necessary to secure a work space for removing the center 67 on the side of the tailstock 65, and the factory space can be used effectively.

  In addition, this invention is not restricted to description of the above-mentioned embodiment, It can implement in a various aspect as follows. Further, the scope of rights encompassed by the present invention is not limited to the above-described embodiment.

S Stroke W Work 1 Machine tool 3 Bed 5 Spindle base 7 Spindle 9 Chuck 11 Spindle electric motor 13 Tailstock 15 Center 17 Tailstock block 19 Guide rail 21 Guide hole 23 Block electric motor 25 Movable sleeve 27 Movable sleeve body 29 Center holder 31 Support pipe 33 Electric motor for sleeve 47 Nut member 49 Press rod 51 Key bolt 53 Key groove 63 Machine tool 65 Tailstock 67 Center 69 Tailstock block 71 Guide rail 73 Guide hole 75 Block electric motor 77 Movable sleeve 79 Center holding part 81 Hydraulic cylinder for sleeve 83 Cylinder body
85 Cylinder cap 87 First piston 89 Second piston 91 First operating rod 93 Second operating rod 95 Guide rod 97 First hydraulic chamber 101 Second hydraulic chamber 105 Third hydraulic chamber 109 Press rod 111 Stopper ring

Claims (2)

In a tailstock that presses and supports the end surface of the other end of the workpiece by the center while holding one end of the workpiece by the spindle of the machine tool,
A tailstock block provided on the bed of the machine tool so as to be opposed to the headstock of the machine tool in the Z-axis direction and movable in the Z-axis direction relative to the headstock;
When the tailstock block is provided so as to be movable in the Z-axis direction, and has a center holding portion that can be taper-fitted to the base end portion of the center on the headstock side, and the center is removed from the center holding portion A movable sleeve configured to move in the Z-axis direction within a stroke set in a normal case other than
An actuator for a sleeve provided on the tailstock block and moving the movable sleeve in the Z-axis direction;
The center is provided in the movable sleeve, extends in the Z-axis direction, is movable in the Z-axis direction integrally with the movable sleeve in the normal case, and the center is the center holding portion of the movable sleeve. A pressing rod for pushing the center toward the headstock when removing from
When the movable sleeve moves beyond the stroke to the opposite side of the headstock side, the pressing rod moves toward the headstock side relative to the movable sleeve, and the end surface of the base end portion of the center Is pressed against the headstock side,
The sleeve actuator includes a cylindrical cylinder main body provided in the tailstock block, a first piston provided in the cylinder main body so as to be liquid-tightly slidable in the Z-axis direction, and the first actuator in the cylinder main body. A second piston provided on the opposite side of the headstock side from the first piston so as to be capable of liquid-tight sliding in the Z-axis direction, a base end portion is integrally connected to the first piston, and a tip end portion is the movable sleeve. A cylindrical first operating rod that is integrally connected to the Z-axis and extends in the Z-axis direction, and is capable of liquid-tight sliding in the Z-axis direction relative to the first operating rod in the first operating rod. A second hydraulic rod, which is supported through and has a base end integrally connected to the second piston and extends in the Z-axis direction, is provided between the first piston and the inner wall surface of the cylinder body. A chamber is defined and said second A sleeve hydraulic cylinder in which a second hydraulic chamber is defined between a stone and an inner wall surface of the cylinder body, and a third hydraulic chamber is defined between the first piston and the second piston. ,
The proximal end portion of the pressing rod is integrally connected to the distal end portion of the second operating rod,
A stopper member that is provided on a distal end side of the second operating rod and restricts the movement of the first operating rod relative to the second operating rod toward the headstock side;
In the normal case, by pressing the third hydraulic chamber, the end surface of the distal end portion of the first operating rod is brought into contact with the stopper member, and the end surface of the distal end portion of the pressing rod and the proximal end portion of the center Configured to maintain a non-contact state with the end face of the
When the movable sleeve moves beyond the stroke to the opposite side of the headstock side by releasing the pressurization state of the second hydraulic chamber and the third hydraulic chamber and pressurizing the first hydraulic chamber, The contact state between the end surface of the distal end portion of the first operating rod and the stopper member is released, and the pressing rod moves toward the headstock relative to the movable sleeve, so that the proximal end portion of the center tailstock end faces of you characterized by being configured to press into the headstock side. In machine tools that perform cutting or grinding on workpieces,
A machine tool comprising the tailstock according to claim 1 .

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