JP4768382B2 - Tailstock - Google Patents

Description

  The present invention is arranged so as to face the spindle of the lathe, the index table, etc., and one end of the workpiece is held on the lathe, the index table, etc. by pressing and supporting the other end of the workpiece, thereby displacing the workpiece by the processing force. This is related to a tailstock that suppresses the workpiece and maintains the machining accuracy of the workpiece.

  The tailstock is disposed so as to face the main shaft of the lathe, the index table, and the like, and the tailstock shaft advances to press one end of the work held on the lathe, the index table, and the like. Thereby, the other end of the workpiece is supported by the core pushing shaft, and the displacement due to the machining force is suppressed, and the machining accuracy is maintained.

  However, the core pushing shaft is supported by the frame of the tailstock, that is, the main body, and is supported so as to be slidable and rotatable, so that an appropriate gap is formed between the through hole of the main body to be inserted. In need of. Therefore, the core pushing shaft is displaced by the machining force from the tool through the workpiece, and there is a problem that micro vibrations, so-called chattering occurs, and the workpiece slightly vibrates together with the core pushing shaft, and the surface roughness and machining accuracy are impaired. .

In order to suppress the above-described chattering of the core pressing shaft during processing without impairing the support of the core pressing shaft in a slidable and rotatable state, in the publication of Patent Document 1, three piezoelectric elements are provided. The shafts are disposed at equal intervals in the through holes, and a voltage is applied to the piezoelectric element only during processing. At the time of non-processing, a gap is formed between the piezoelectric element and the core pressing shaft, and the core pressing shaft is slidable and rotatable with respect to the main body without being constrained by the piezoelectric element. . At the time of processing, the piezoelectric element expands due to the application of voltage, and the radially inner portion is displaced toward the core pressing shaft to eliminate the gap with the core pressing shaft and further press the core pressing shaft. Accordingly, the gap between the core pressing shaft and the piezoelectric element is eliminated, and the displacement of the core pressing shaft is regulated by the piezoelectric element acting as a clamp member. Therefore, during processing, the core pushing shaft is free from chatter, and it can be avoided that the processing accuracy of the workpiece is impaired.
Japanese Patent Publication No. 6-88166

  However, in the device of Patent Document 1, the piezoelectric element also serves as a bearing member. When not processed, the core pressing shaft is in contact with the inner surface in the radial direction of the piezoelectric element. The three piezoelectric elements slide and rotate while making particularly strong contact with the radially inner side surface of any one of the three piezoelectric elements. Therefore, the piezoelectric element with which the core pushing shaft is in strong contact is quickly worn out, and if the wear exceeds the allowable amount, the concentricity of the core pushing shaft with the lathe or index table is impaired, and the core pushing shaft is sufficiently Since it becomes impossible to press, it needs to be replaced.

  However, since the piezoelectric element is attached to the groove formed in the through hole of the main body, the replacement work of the piezoelectric element is not easy, and the electric wire that applies voltage to the piezoelectric element is not damaged during the replacement. Therefore, it is necessary to pay sufficient attention, and from this point of view, it is not easy to replace the piezoelectric element.

  In view of the above-mentioned problems of the prior art, the object of the present invention is to securely clamp the core pressing shaft during processing to suppress the chatter of the core pressing shaft, to maintain the processing accuracy of the workpiece, and to support the shaft pressing shaft. An object of the present invention is to provide a tailstock that can easily perform replacement of a bearing member when the member is worn.

  The present invention has been made to achieve the above object, and includes a main body having a through hole, a core shaft that is inserted into the through hole and supported so as to be slidable and rotatable, and the core shaft. It is premised on a core push stand provided with a fluid pressure drive device that drives and presses against a workpiece.

  In the present invention, the tailstock is a pair of bearing members that are provided between the through hole and the corestock shaft and that support the corestock shaft in a slidable and rotatable manner. And a pair of bearing members that can be inserted from the side opposite to the workpiece and spaced apart from each other in the axial direction, and a clamp device that is provided between the pair of bearing members in the axial direction and surrounds the core pressing shaft. And a clamp device including a high-pressure fluid supply device that supplies a high-pressure fluid to the internal space of the hollow member, and the hollow member in the clamp device is fixed to the main body and radially inward. The portion is reduced in diameter with the inflow of the high-pressure fluid to press the core pressing shaft, and when the high-pressure fluid is not supplied, the core pressing shaft is not pressed.

  In the present invention, the bearing member may be fitted and held in an annular holding member and inserted into the through hole via the holding member. Furthermore, the holding member may have a flange portion having a diameter larger than that of the through hole, and the flange portion may be fixed to the work-side end surface or the non-work-side end surface of the main body.

  According to the tailstock of the present invention, the hollow member in the clamping device has a radially inner portion reduced in diameter as the high-pressure fluid is supplied to the inner space, and presses the corestock shaft. The push shaft is integrated with the main body via the hollow member, so that the slight vibration caused by the processing force, so-called chatter, is suppressed, and the processing accuracy of the workpiece is maintained. Further, the hollow member does not press the core pushing shaft when high-pressure fluid is not supplied, that is, when it is not processed, so it does not wear due to sliding or rotation of the core pushing shaft and needs to be replaced due to wear. do not do. Further, since the hollow member surrounds the core pushing shaft, the radially inner portion presses the core pushing shaft all around as the high pressure fluid flows in, and the core pushing shaft is moved in the radial direction by the processing force. It is possible to effectively suppress the occurrence of micro vibrations, so-called chatter, due to displacement.

  Further, according to the core stock of the present invention, the clamping device is provided between the pair of bearing members, and the pair of bearing members are respectively provided between the through hole of the main body and the core shaft from the work side and the non-work side. Because it is mounted, even if a pair of bearing members needs to be replaced due to wear, in the replacement work, removal of the worn product and installation of the replacement product can be easily performed without being hindered by the clamp device, It is securely attached in place. Further, since the hollow member is disposed between the two bearing members, the pair of bearing members has a sufficient interval while the axial length of the through hole is suppressed, that is, the axial length of the main body is suppressed as much as possible. It is possible to support the core pushing shaft, to reduce the resistance of the core pushing shaft, particularly the sliding resistance, to suppress wear, and to support the core pushing shaft with high accuracy.

  Further, if the bearing member is configured to be mounted in the through hole of the main body via the holding member, the bearing member is integrated with the holding member at the time of replacement, that is, while being assembled to the holding member, from the through hole. Removal and attachment to the through hole are possible. Therefore, workability is ensured, and the bearing member can be easily detached from the holding member and can be easily fitted into the holding member without damage to the bearing member.

  Further, if the holding member has a flange portion having a diameter larger than the through hole of the main body, and the flange portion is fixed to the work side end surface or the non-work side end surface of the main body, the holding member is a taper pin or the like. It can be fixed to the work-side end surface or the non-work-side end surface of the main body via a member that removably fixes a holding member such as a pin member or screw member, and the bearing member can be easily replaced by removing the holding member. can do. Note that the flange portion does not necessarily have to be a circle, and only the portion that engages with a member that removably fixes a holding member such as an ellipse or a star member, such as a pin member or a screw member, is formed to have a larger diameter than the through hole. The flange portion may be formed.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 to FIG. 3 are cross-sectional views of the tailstock 30 according to the first embodiment of the present invention. 1 and 3 show the time when the core pushing shaft is finally retracted and the time when the core push shaft is advanced, respectively. FIG.

  The tailstock 30 of this embodiment includes a main body 1, a metal holder 2, a shaft 6, a center 7, a plunger 9, a plunger guide 10, pipe pipes 14, 15, 16, a clamp ring 8, a front lid 12, and a rear side. A lid 11 is provided.

  The main body 1 has a through hole 1a and a base portion 1d. The base portion 1d is fixed to a slide rail 51 of a machine tool, and faces a workpiece 52 held on a main shaft or an index table (not shown) of the machine tool.

  In the metal holder 2, the oil-impregnated metal 4 is fitted into the inner peripheral surface of the metal holding portion 2a, the outer peripheral surface of the metal holding portion 2a is fitted into the through hole 1a, and the flange portion 2b having a larger diameter than the through hole 1a is provided. It is fixed to the workpiece side end surface 1b of the main body 1 through a hexagon socket head bolt 21 so as to be detachable. In the metal holder 3, the oil-impregnated metal 5 is fitted into the inner peripheral surface of the metal holding portion 3a, the outer peripheral surface of the metal holding portion 3a is fitted into the through hole 1a, and the flange portion 3b having a larger diameter than the through hole 1a is provided. It is fixed to the non-workpiece side end surface 1c of the main body 1 through a hexagon socket bolt 22 so as to be detachable. Accordingly, the oil-impregnated metals 4 and 5 fitted in the metal holders 2 and 3 are separated from each other in the direction of the axis C of the through hole 1a.

  The shaft 6 extends in the direction of the axis C of the through hole 1a, is inserted into the oil-impregnated metals 4 and 5, and is supported so as to be slidable and rotatable. The center 7 has a front end portion, that is, a workpiece side end portion formed in a conical shape, and a rear side, that is, a non-workpiece side is formed in a tapered shape and is fitted into a tapered hole formed on the workpiece side of the shaft 6. The shaft 6 is integrated with the shaft 6 to form a core pressing shaft together with the shaft 6.

  The plunger 9 is inserted into a cylinder hole 6a formed on the side opposite to the workpiece of the shaft 6, and has a piston portion 9a on the outer peripheral surface of which the piston ring 13 is attached at the workpiece side end. The plunger guide 10 is fitted to the end of the cylinder hole 6a opposite to the workpiece and integrated with the shaft 6, and has a through hole through which the plunger 9 is inserted.

  Piping pipes 14 and 15 are connected to the end of the plunger 9 opposite to the workpiece, and communicate passages 9b and 9c provided in the plunger 9 with a hydraulic pump (not shown).

  In the clamp ring 8, the clamp device portion 3 c is formed by the metal holder 3 between the oil-impregnated metals 4 and 5, and the outer peripheral surface has an annular groove 8 a and is fitted to the inner peripheral surface of the clamp device portion 3 c. By being fixed to, the radially inner portion of the hollow member is formed, and the hollow member is formed with the clamp device portion 3c to surround the shaft 6.

  The pipe 16 is connected to the main body 1 and is not shown in the internal space of the hollow member via a passage 1e provided in the main body 1 and two passages 3d provided at equal intervals in the circumferential direction in the clamp device portion 3c. Supply high pressure oil from hydraulic pump.

  The front lid 12 is fixed to the metal holder 2 via a hexagon socket head bolt 23. The rear lid 11 fixes the plunger 9 to the main body 1 by fitting the rear end portion of the plunger 9 and fitting the rear lid 11 to the metal holder 3.

  In the present embodiment, a hydraulic pressure driving device is used as a fluid pressure driving device that drives the shaft 6 and the center 7 that are core pushing shafts to press the workpiece 52, and is driven by a hydraulic pump (not shown) and By adjusting the pressure to a predetermined value via a regulator (not shown), the pressing force of the core pressing shaft is adjusted to a value that matches the machining conditions of the workpiece 52. Further, as the high-pressure fluid supplied to the internal space of the hollow member, high-pressure oil is used in the same manner as the fluid pressure driving device of the core pushing shaft, that is, the hydraulic driving device, and is supplied from the hydraulic pump and specified via the regulator. Adjusted to the pressure of

  The piston portion 9 a of the plunger 9 is slidable relative to the cylinder hole 6 a of the shaft 6, and the plunger 9 is fixed to the main body 1 via the rear lid 11 and the metal holder 3. The hole 6a, that is, the shaft 6 slides.

  When the hydraulic oil from the hydraulic pump flows into the cylinder hole 6a between the rear end of the piston portion 9a and the plunger guide 10 via the pipe 14 and the passage 9c, as shown in FIG. Retreats, and the shaft 6 fitted with the plunger guide 10 and integrated with the plunger guide 10 retreats until it abuts against the piston portion 9a and is regulated. Further, when the hydraulic oil flows into the cylinder hole 6a from the front end of the piston portion 9a through the piping pipe 15 and the passage 9b, the shaft 6 is regulated by the center 7 contacting the work 52 as shown in FIG. Until the workpiece 52 is pressed. In addition, when the workpiece | work 52 is not attached, when not regulated by the workpiece | work 52, the shaft 6 advances until the plunger guide 10 contact | abuts to the piston part 9a and is regulated.

  As described above, the hydraulic oil flows into the cylinder from the front end of the piston portion 9a through the pipe pipe 15 and the passage 9b from the state in which the shaft 6 and the center 7 which are the core pushing shafts shown in FIG. Then, as shown in FIG. 2, the shaft 6 and the center 7 move forward to press the work 52 held on the lathe spindle, the index table or the like, and the work 52 is supported by the center 7.

  During processing of the workpiece 52, high pressure oil is supplied from the hydraulic pump, and the high pressure oil flows into the internal space of the hollow member formed by the clamp device portion 3c and the clamp ring 8 through the pipe 16 and the passages 1e and 3d. To do. The annular groove 8a provided on the outer peripheral surface of the clamp ring 8 forms an internal space and a hollow member, and the clamp ring 8 has a thin thickness at the annular groove 8a portion. It is easily deformed by high-pressure oil and comes into contact with the shaft 6, that is, the diameter is reduced and the shaft 6 is pressed. Since the clamp ring 8 is fitted into the metal holder 3 and integrated with the metal holder 3, the clamp ring 8 is integrated with the main body 1 via a hexagon socket bolt 22 that fixes the metal holder 3. Therefore, the shaft 6 is placed in a clamped state, and its rotation and sliding are restricted, and the entire circumference is supported by the clamp ring 8, and the radial displacement, specifically, the radius due to the machining force applied through the workpiece 52. Directional displacement is suppressed. Thereby, the shaft 6 is suppressed from micro-vibration during processing, so-called chattering, and the workpiece 52 is maintained in machining accuracy.

  The oil-impregnated metals 4 and 5 that are a pair of bearing members are spaced apart from each other in the direction of the axis C of the through-hole 1c and are disposed at both ends of the main body 1, so that the shaft 6 is supported with high accuracy and the shaft 6 Resistance, particularly sliding resistance can be reduced, and wear of the oil-impregnated metals 4 and 5 can be suppressed.

  If the oil-impregnated metals 4 and 5 are worn more than allowed, they are replaced as follows. The front lid 12 and the rear lid 11 are removed, and the shaft 6, the center 7 and the plunger guide 10, which are integral parts, are removed while the plunger 9 is assembled. The hexagon socket head cap bolts 21 and 22 are removed, and the metal holders 2 and 3 are removed from the main body 1 while the oil-impregnated metals 4 and 5 are fitted. The oil-impregnated metals 4 and 5 are pressed into metal by pressing the end surfaces of the oil-impregnated metals 4 and 5 with a cylindrical jig that can be inserted into the inner peripheral surfaces of the metal holders 2 and 3 using a vise or a press device. Remove from holders 2 and 3.

  Next, a cylindrical jig that can be inserted into the inner peripheral surface of the oil-impregnated metal 4 or 5 with a flange is used, and the flange of the jig is the end face of the oil-impregnated metal 4 or 5 by using a vise or a press device. Is pressed into the metal holders 2 and 3. The metal holders 2 and 3 are fitted into the through holes 1 a of the main body 1, and fixed to the main body 1 with hexagon socket head cap bolts 21 and 22. The shaft 6, the center 7 and the plunger guide 10 are inserted into the oil-impregnated metals 4 and 5 while the plunger 9 is assembled, and then the oil-impregnated metals 4 and 5 are attached by attaching the front lid 12 and the rear lid 11. The replacement work is completed. As described above, since the oil-impregnated metals 4 and 5 can be exchanged with the oil-removed metals 4 and 5 removed from the main body 1, workability is ensured, and the oil-impregnated metals 4 and 5 can be easily replaced without damage.

  FIG. 4 is a cross-sectional view showing the tailstock 40 according to the second embodiment of the present invention, and shows the time when the tailstock shaft is retracted last time. The through-hole 1a of the main body 1 is stepped so that the central portion 1aa is formed with a small diameter, and the clamp ring 8 having an annular groove 8a on the outer peripheral surface is fitted into the central portion 1aa of the through-hole 1a. Fixed to. Thereby, the hollow member of the clamping device of the shaft 6 is formed by the main body 1 and the clamp ring 8. Similar to the tailstock 30 of the first embodiment, during processing, high-pressure oil flows into the internal space of the hollow member from the hydraulic pump (not shown) through the pipe 16 and the passage 1e, and is the radially inner portion of the hollow member. The clamp ring 8 reduces the diameter and presses the shaft 6. As a result, the shaft 6 is integrated with the main body 1, and the entire circumference is pressed to restrict radial displacement, thereby suppressing fine vibration during processing, so-called chatter.

  In both the first and second embodiments of the present invention, a hydraulic drive device is used as a fluid pressure drive device that drives the core pushing shaft and presses against the workpiece 52. However, a pneumatic drive device is used as the fluid pressure drive device. May be. In both the first and second embodiments, the high-pressure fluid supplied to the internal space of the hollow member surrounding the core pressing shaft is high-pressure oil, but it may be high-pressure air. In either case, the same effects as those of the first and second embodiments are obtained.

  In both the first and second embodiments of the present invention, the center 7 is fitted to the shaft 6 and integrated with the shaft 6 so as not to move relative to it, but is provided so as to be rotatable relative to the shaft 6 via a bearing. May be. During processing, the shaft 6 is clamped, but the center 7 can rotate integrally with the workpiece 52.

  When one end of the work 52 is held by the index table, a chucking device may be provided at the front end portion of the shaft 6 without providing the center 7, and the other end of the work 52 may be held by the device. The shaft 6 is clamped at the time of machining after indexing, so-called chatter due to machining force is suppressed, and the machining accuracy of the workpiece 52 is maintained.

  The present invention is not limited to any of the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

It is sectional drawing which shows the tailstock 30 of the 1st Example of this invention, and shows the time of the last retreat of a corestock shaft. It is a principal part enlarged view in FIG. In the tailstock 30 of the first embodiment of the present invention, the time of advancement of the tailstock shaft is shown. It is sectional drawing which shows the tailstock 40 of the 2nd Example of this invention, and shows the time of the last retreat of a corestock shaft.

DESCRIPTION OF SYMBOLS 1 Main body 1a Through-hole 1aa Center part of 1a Through-hole 1b Workpiece side end surface 1c Non-workpiece side end surface 1d Base part 2 Metal holder 2a Metal holding part 2b Flange part 3 Metal holder 3a Metal holding part 3b Flange part 3c Clamping device part 3d Passage 4 Oil impregnated metal 5 Oil impregnated metal 6 Shaft 6a Cylinder hole 7 Center 8 Clamp ring 8a Annular groove 9 Plunger 9a Piston portion 9b Passage 9c Passage 10 Plunger guide 11 Rear lid 12 Front lid 13 Piston ring 14 Piping pipe 15 Piping pipe 16 Piping Pipe 21 Hexagon socket head cap screw 22 Hexagon socket head cap screw 23 Hexagon socket head cap screw 30 Core press stand 40 Core press stand 51 Slide rail 52 Workpiece C

Claims (3)

A tailstock including a main body having a through hole, a core pushing shaft that is inserted into the through hole and supported so as to be slidable and rotatable, and a fluid pressure driving device that drives the core pushing shaft to press the workpiece. In
A pair of bearing members provided between the through hole and the core pressing shaft and supporting the core pressing shaft in a slidable and rotatable manner, each of which can be inserted from the work side and the non-work side and are mutually connected. A pair of bearing members provided to be spaced apart in the axial direction;
A clamping device provided between a pair of bearing members in the axial direction, a hollow member disposed to surround the core pressing shaft, and a high-pressure fluid supply device for supplying high-pressure fluid to an internal space of the hollow member And a clamping device including
The hollow member in the clamp device is fixed to the main body, and the radially inner portion is reduced in diameter with the inflow of the high-pressure fluid to press the core pushing shaft, and when the high-pressure fluid is not supplied, A tailstock that does not press the tailstock shaft. The core holder according to claim 1, wherein the bearing member is fitted and held in an annular holding member, and is inserted into the through hole through the holding member. 3. The core pressing according to claim 2, wherein the holding member has a flange portion having a diameter larger than that of the through hole, and the flange portion is fixed to a work side end surface or a non-work side end surface of the main body. Stand.

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