JP2011025326A - U-shaft holder unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a U-shaft holder unit capable of easily inhibiting a shift in position of a cutting tool. <P>SOLUTION: The U-shaft holder unit 1 for moving a cutter tip T in a direction intersecting with a spindle rotation center P includes a hydraulic pressure generating means 7 for generating hydraulic pressure based on rotation force of a driving shaft 5 provided along the spindle rotation center P, and the cutter tip T is moved by the hydraulic pressure from the hydraulic pressure generating means 7. The U-shaft holder unit 1 includes: a first hydraulic cylinder chamber 9 serving as the hydraulic pressure generating means 7 having a first piston 8 working in a direction along the spindle rotation center P by driving of a driving rod 8A; a second hydraulic cylinder chamber 11 having a second piston 10 having the cutter tip T attached to the leading edge of a rod 10A and working in the direction intersecting with the spindle rotation center P; and a hydraulic closed circuit for connecting between the first hydraulic cylinder chamber 9 and the second hydraulic cylinder chamber 11. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a U-axis holder unit mounted on a machine tool such as a machining center.

  As a conventional example of a U-axis holder unit provided with a conversion mechanism that converts the amount of rotation of the drive shaft around the center of rotation of the spindle into the cutting feed amount of the cutting tool in the direction orthogonal to the center of rotation of the main shaft, Patent Documents 1 and 2 describe Things. As the conversion mechanism, Patent Document 1 describes a technique composed of a planetary gear mechanism and a differential gear mechanism. A technique is described in which the screw rod 31 is moved by a feed screw action by rotation of the driving bevel gear 11 to slide the slide portion 3 with the blade tool from 72 to the planetary gear mechanism 10 through the differential gear mechanism 6.

  On the other hand, Patent Document 2 describes a technique composed of a rack and pinion mechanism as the conversion mechanism, and a pinion 12 is formed on the head of the feed shaft 11 when described with the reference numeral. A technique for engaging the rack 13 of the rack slider 9 to which the tool post 14 is attached with the pinion 12 is described.

JP-A-5-301101 (paragraphs [0007] to [0013]) Japanese Patent No. 3293252 (paragraph [0009])

  However, both the techniques of Patent Document 1 and Patent Document 2 have a problem that the position of the cutting tool tends to be displaced due to backlash due to the structure using the gear mechanism.

  The present invention was created in order to solve such problems, and an object thereof is to provide a U-axis holder unit that can easily suppress the displacement of the cutting tool.

  In order to solve the above-described problems, the present invention generates hydraulic pressure based on the rotational force of a drive shaft provided along the spindle rotation center in a U-axis holder unit that moves the cutting tool in a direction intersecting the spindle rotation center. A hydraulic pressure generating means is provided in the housing, and the cutting tool is moved by the hydraulic pressure from the hydraulic pressure generating means.

  According to the said structure, since the cutting feed amount of a blade tool will be controlled by hydraulic pressure, the feed precision of a blade tool will improve and the position shift of a blade tool can be suppressed.

  According to the present invention, there is provided a first hydraulic cylinder chamber as the hydraulic pressure generating means having a first piston that operates in a direction along a spindle rotation center by driving a rod, and a cutting tool attached to a tip end side of the rod. And a second hydraulic cylinder chamber having a second piston that operates in a moving direction of the first hydraulic cylinder, and a hydraulic closed circuit that connects the first hydraulic cylinder chamber and the second hydraulic cylinder chamber.

  According to this configuration, since the hydraulic circuit is simple, the hydraulic mechanism can be easily accommodated in the housing, and the U-axis holder unit can be made compact.

  In the invention, it is preferable that the closed hydraulic circuit has a configuration in which head-side oil chambers and rod-side oil chambers of the first hydraulic cylinder chamber and the second hydraulic cylinder chamber are connected to each other.

  As the hydraulic closed circuit, it is possible to configure a hydraulic closed circuit only between the head side oil chambers, and the rod side oil chamber can be an air chamber. Although a closed circuit can be configured and the head side oil chamber can be an air chamber, a vent hole for opening the air chamber to the atmosphere is required. On the other hand, if a hydraulic closed circuit is configured for both the head-side oil chambers and the rod-side oil chambers, it is not necessary to provide a vent hole, so that the housing can be easily sealed.

  Further, the present invention is characterized in that the rod of the first piston is driven by an operation of a feed screw mechanism having the drive shaft as a male screw.

  According to this configuration, the number of parts can be reduced and the structure can be reduced as a mechanism for converting the rotation of the drive shaft into the operation of the first piston.

  Further, the present invention provides a third hydraulic cylinder chamber having a third piston that is arranged in parallel with the first hydraulic cylinder chamber and operates in a direction along the spindle rotation center by driving a rod, and the second hydraulic cylinder chamber. A hydraulic closed circuit that connects the third hydraulic cylinder chamber and the fourth hydraulic cylinder chamber, and a fourth hydraulic cylinder chamber that is provided in parallel and has a fourth piston that operates as a balance weight in a direction intersecting the spindle rotation center. And the feed screw mechanism includes a slider that is screwed to the male screw of the drive shaft, and the rods of the first piston and the third piston are attached to the slider. Features.

  According to this configuration, the number of parts on the balance weight side and reduction in size can be achieved by attaching the drive rod of the third hydraulic cylinder together with the drive rod of the first hydraulic cylinder to the slider.

  In addition, the present invention is characterized in that a biasing member that constantly biases the slider in a direction along the drive shaft is provided.

  Although the backlash of the feed screw mechanism does not occur much as compared with the gear mechanism, the backlash of the feed screw mechanism can be reliably suppressed by providing a biasing member that constantly biases the slider in the direction along the drive shaft. The feed accuracy is further improved.

  According to the present invention, the cutting feed amount of the cutting tool is controlled by hydraulic pressure, the feeding accuracy of the cutting tool is improved, and the positional deviation of the cutting tool is suppressed.

It is a plane sectional view of the U-axis holder unit of the present invention. It is AA sectional drawing in FIG. It is BB sectional drawing in FIG. It is C arrow line view in FIG. It is action | operation explanatory drawing of the U-axis holder unit of this invention.

  In FIG. 1, a detachable holder 2 is integrally provided on the other end side of the U-axis holder unit 1 that is attached to a main shaft (not shown) of a machine tool such as a machining center by closely contacting shank surfaces. The detachable holder 2 may be formed integrally with the housing 3 of the U-axis holder unit 1 or may be a separate member.

  The U-axis holder unit 1 includes a drive shaft 5 that rotates about a main shaft rotation center P. Reference numeral 6 denotes a bearing for supporting the drive shaft 5 on the housing cap 4. Although not described in detail, the pull stud 2a of the attachment / detachment holder 2 is rotatably attached to the attachment / detachment holder 2, for example, and is rotated by being connected to a rotation member (not shown) on the main shaft side. The drive shaft 5 rotates by being connected to the pull stud 2a via a speed reducer (not shown), for example. Further, when the pull stud 2a is configured so as not to rotate with respect to the detachable holder 2, for example, the pull stud 2a is hollow, and the rotating member on the main shaft side and the drive shaft 5 are connected via the hollow portion. The

  In FIG. 2, an appropriate rotational speed difference is generated between the housing 3 and the drive shaft 5 on one end side of the U-axis holder unit 1, thereby intersecting the main shaft rotation center P, orthogonal in the present embodiment. A cutting tool (cutter tip T) that is cut and fed in the direction of cutting is provided. The U-axis holder unit 1 according to the present invention has a structure that converts the amount of rotation of the drive shaft 5 into the cutting feed amount of the cutter tip T, and has a hydraulic pressure generating means 7 that generates hydraulic pressure based on the rotational force of the drive shaft 5. The main feature is that the cutter tip T is moved by the hydraulic pressure from the hydraulic pressure generating means 7.

  The U-axis holder unit 1 includes a first hydraulic cylinder chamber 9 as the hydraulic pressure generating means 7 having a first piston 8 that operates in a direction along the spindle rotation center P by driving a rod 8A (hereinafter referred to as a drive rod). A cutter tip T is attached to the distal end side of the rod 10A, and a second hydraulic cylinder chamber 11 having a second piston 10 that operates in a direction perpendicular to the spindle rotation center P in this embodiment in the moving direction of the cutter tip T. And a hydraulic closed circuit that connects the first hydraulic cylinder chamber 9 and the second hydraulic cylinder chamber 11.

  In the present embodiment, the first piston 8 is operated by the operation of the feed screw mechanism 12 having the drive shaft 5 as a male screw. As shown in FIG. 1, a male screw 5A is screwed at the tip of the drive shaft 5, and a slider 13 is screwed into the male screw 5A. The slider 13 is formed as a circular member whose outer periphery is slidably in contact with the inner peripheral wall 14A of the slider accommodating space 14 of the housing 3 and is screwed with the male screw 5A at the center, but the first piston 8 is in an eccentric position. Since it is connected to the drive rod 8 </ b> A and the like, it cannot rotate relative to the housing 3, and moves along the drive shaft 5 without being accompanied by the drive shaft 5.

  In FIG. 2, the first hydraulic cylinder chamber 9 and the second hydraulic cylinder chamber 11 are formed, for example, in such a manner as to be drilled in a solid portion on one end side of the housing 3. The first hydraulic cylinder chamber 9 is formed of, for example, a hole space drilled in the one end wall 14B of the slider accommodating space 14, and the opening is closed by a spring support piece 17 to be described later, thereby forming a cylinder chamber. The Further, the outer peripheral surface on one end side of the housing 3 is notched at two locations across the spindle rotation center P, and each notch bottom surface 15 forms a plane parallel to the spindle rotation center P and faces each other. It is formed as follows. The second hydraulic cylinder chamber 11 is formed of a hole space that is drilled so as to penetrate through both the cutout bottom surfaces 15, and both openings are closed by a flat housing plate 16 that is fixed to each cutout bottom surface 15. This constitutes a cylinder chamber.

  A disc-like spring support piece 17 is fixed to one end wall 14B of the slider accommodating space 14, and the drive rod 8A of the first piston 8 is inserted into the spring support piece 17 and connected to the slider 13. Yes. Of course, the hole of the spring support piece 17 through which the drive rod 8A is inserted is appropriately subjected to oil seal processing. Between the spring support piece 17 and the slider 13, as a biasing member that constantly biases the slider 13 in the direction along the drive shaft 5, in this embodiment, toward the other end side of the U-axis holder unit 1. The compression coil spring 30 is provided.

  The rod 10A of the second piston 10 passes through one housing plate 16, and a blade support piece 18 having a cutter tip T is fixed to the tip of the housing plate 16. An oil seal process is appropriately performed on the hole of the housing plate 16 through which the rod 10A is inserted. In particular, the outer surface side of the hole is formed with a large diameter, and a ring-shaped sealing member 31 for sealing a gap with the rod 10A is attached to the large diameter portion. The blade support piece 18 has an L-shape when viewed from the side, one side of which is fixed to the rod 10A, and the other side is attached to the end surface of the housing 3 in order to move the cutter chip T without rattling. It is slidably fitted in the provided guide groove 19 (see FIG. 1).

  As the hydraulic closed circuit, the piston head is sandwiched between the head-side oil chamber 9A formed on the piston head side with the first piston 8 of the first hydraulic cylinder chamber 9 interposed therebetween, and the second piston 10 of the second hydraulic cylinder chamber 11 sandwiched therebetween. 11 A of head side oil chambers formed in the side are connected by the oil path 20, the circuit is filled with hydraulic fluid, and the rod side formed in the rod side across the first piston 8 of the first hydraulic cylinder chamber 9 The oil chamber 9B communicates with the rod-side oil chamber 11B formed on the rod side across the second piston 10 of the second hydraulic cylinder chamber 11 through an oil passage 21, and the circuit is filled with hydraulic oil.

  Similar to the hydraulic mechanism for the cutter tip T described above, the U-axis holder unit 1 is provided with a hydraulic mechanism for a balance weight. As shown in FIG. 1, the balance weight hydraulic mechanism is provided in parallel with the first hydraulic cylinder chamber 9, and has a third piston 22 that operates in the direction along the spindle rotation center P by driving the drive rod 22A. The second piston 10 is provided in parallel with the three hydraulic cylinder chambers 23 and the second hydraulic cylinder chamber 11 and intersects with the spindle rotation center P, in the present embodiment, in a direction orthogonal to the spindle rotation center P and as a balance weight. And a fourth hydraulic cylinder chamber 25 having a fourth piston 24 that operates in the opposite direction, and a hydraulic closed circuit that connects the third hydraulic cylinder chamber 23 and the fourth hydraulic cylinder chamber 25. Similarly to the drive rod 8 </ b> A, the drive rod 22 </ b> A of the third piston 22 is connected to the slider 13 through the spring support piece 17.

  The hydraulic mechanism for the balance weight is provided at a position 180 degrees opposite to the hydraulic mechanism for the cutter tip T across the spindle rotation center P, and the operation direction of the fourth piston 24 is the opposite direction to the second piston 10. Except for this point, the configuration is the same as that of the hydraulic mechanism for the cutter tip T, and thus detailed description thereof is omitted.

  Since each hydraulic mechanism has a simple structure and becomes compact, all of them can be easily built in the housing (housing 3, housing cap 4, housing plate 16) of the U-axis holder unit 1 and can move through the inside and outside of the housing. As shown in FIG. 3, the members are only the rod 10 </ b> A of the second piston 10 and the rod of the fourth piston 24. Therefore, by sealing the hole of the housing through which these rods are inserted with the sealing member 31, the inside of the housing can be easily sealed, and the penetration of coolant and chips into the housing can be suppressed. .

  The U-axis holder unit 1 is configured as described above. In FIG. 5, when the rotational speed of the drive shaft 5 is higher than the rotational speed of the housing 3 (main shaft), the slider 13 screwed to the male screw 5 </ b> A is used as the feed screw. The first hydraulic cylinder is moved by the action to move to one end side of the U-axis holder unit 1 and the first piston 8 and the third piston 22 move to one end side of the U-axis holder unit 1 through the drive rods 8A and 22A, respectively. Hydraulic pressure is generated in the chamber 9 and the third hydraulic cylinder chamber 23. In the hydraulic closed circuit, the hydraulic oil in the head side oil chamber 9A of the first hydraulic cylinder chamber 9 flows into the head side oil chamber 11A of the second hydraulic cylinder chamber 11 through the oil passage 20, and the second hydraulic cylinder chamber 11 The hydraulic oil in the rod side oil chamber 11 </ b> B flows into the rod side oil chamber 9 </ b> B of the first hydraulic cylinder chamber 9 through the oil passage 21. The same applies to the third hydraulic cylinder chamber 23 and the fourth hydraulic cylinder chamber 25. Thereby, the 2nd piston 10 and the 4th piston 24 act | operate, and the cutter tip T and the balance weight move to a feed side.

  When the rotational speed of the drive shaft 5 is lower than the rotational speed of the housing 3 (main shaft), the operation is reversed, the slider 13 moves to the other end side of the U-axis holder unit 1, and the first piston 8 moves to the U-axis holder unit. The hydraulic oil flows from the head side oil chamber 11A to the head side oil chamber 9A, and the hydraulic oil flows from the rod side oil chamber 9B to the rod side oil chamber 11B. The same applies to the third hydraulic cylinder chamber 23 and the fourth hydraulic cylinder chamber 25. As a result, the cutter tip T and the balance weight move to the return side.

  As described above, if the hydraulic pressure generating means 7 for generating the hydraulic pressure based on the rotational force of the drive shaft 5 is provided in the housing 3 and the cutter tip T is moved by the hydraulic pressure from the hydraulic pressure generating means 7, the cutter Since the cutting feed amount of the tip T is controlled by hydraulic pressure, the feed accuracy of the cutter tip T is improved, and the displacement of the cutter tip T can be suppressed.

  Further, a first hydraulic cylinder chamber 9 as a hydraulic pressure generating means 7 having a first piston 8 that operates in a direction along the spindle rotation center P by driving the drive rod 8A, and a cutter tip T is attached to the tip side of the rod 10A. And a second hydraulic cylinder chamber 11 having a second piston 10 that operates in the moving direction of the cutter tip T, and a hydraulic closed circuit that connects the first hydraulic cylinder chamber 9 and the second hydraulic cylinder chamber 11. With this configuration, since the hydraulic circuit is simple, the hydraulic mechanism can be easily accommodated in the housing 3 and the U-axis holder unit 1 can be made compact.

  As the hydraulic closed circuit, a hydraulic closed circuit is formed only between the head side oil chambers 9A and 11A of the first hydraulic cylinder chamber 9 and the second hydraulic cylinder chamber 11, and the rod side oil chambers 9B and 11B are It is also possible to use an air chamber, and conversely, it is possible to form a closed hydraulic circuit only between the rod-side oil chambers 9B and 11B, and the head-side oil chambers 9A and 11A can be used as air chambers. However, in this case, since a vent hole for opening the air chamber to the atmosphere is required, it is difficult to make the housing 3 have a sealed structure. On the other hand, if a hydraulic closed circuit is configured for both the head side oil chambers 9A and 11A and the rod side oil chambers 9B and 11B, there is no need to provide a vent hole, so that the housing 3 can be easily sealed. .

  Further, if the rod 8A of the first piston 8 is configured to be driven by the operation of the feed screw mechanism 12 using the drive shaft 5 as a male screw, the mechanism for converting the rotation of the drive shaft 5 into the operation of the first piston 8 is as follows. The number of parts can be reduced and the size can be reduced. In particular, when the balance weight hydraulic mechanism is also provided as in the present embodiment, the drive rod 22A and the drive rod 22A are coupled to the slider 13 of the feed screw mechanism 12, thereby reducing the number of parts on the balance weight side. It can also be made compact.

  Further, although the backlash of the feed screw mechanism does not occur so much as compared with the gear mechanism, if a biasing member (compression coil spring 30) for constantly biasing the slider 13 in the direction along the drive shaft 5 is provided, the feed screw The backlash of the mechanism 12 can be reliably suppressed, and the feeding accuracy of the cutter tip T is further improved.

  The preferred embodiment of the present invention has been described above. Examples of the urging member include elastic members such as a disc spring and a leaf spring in addition to the compression coil spring.

1 U-axis holder unit 3 Housing 5 Drive shaft 7 Hydraulic pressure generating means 8 First piston 8A Drive rod (rod)
9 first hydraulic cylinder chamber 9A head side oil chamber 9B rod side oil chamber 10 second piston 10A rod 11 second hydraulic cylinder chamber 11A head side oil chamber 11B rod side oil chamber 12 feed screw mechanism 13 slider 22 third piston 23 first 3 Hydraulic cylinder chamber 24 Fourth piston 25 Fourth hydraulic cylinder chamber 30 Compression coil spring (biasing member)
P Spindle rotation center T Cutter tip (cutting tool)

Claims (6)

In the U-axis holder unit that moves the cutting tool in a direction crossing the spindle rotation center,
The housing is provided with hydraulic pressure generating means for generating hydraulic pressure based on the rotational force of the drive shaft provided along the spindle rotation center,
A U-axis holder unit characterized in that the cutting tool is moved by hydraulic pressure from the hydraulic pressure generating means. A first hydraulic cylinder chamber as the hydraulic pressure generating means having a first piston that operates in the direction along the spindle rotation center by driving a rod;
A second hydraulic cylinder chamber having a second piston that is attached to the distal end side of the rod and that operates in the moving direction of the blade;
A hydraulic closed circuit connecting the first hydraulic cylinder chamber and the second hydraulic cylinder chamber;
The U-axis holder unit according to claim 1, comprising:   3. The U-axis according to claim 2, wherein the hydraulic closed circuit has a configuration in which head-side oil chambers and rod-side oil chambers of the first hydraulic cylinder chamber and the second hydraulic cylinder chamber are connected to each other. Holder unit.   4. The U-axis holder unit according to claim 2, wherein the rod of the first piston is driven by an operation of a feed screw mechanism using the drive shaft as a male screw. A third hydraulic cylinder chamber provided in parallel with the first hydraulic cylinder chamber and having a third piston that operates in a direction along the spindle rotation center by driving of a rod;
A fourth hydraulic cylinder chamber provided in parallel with the second hydraulic cylinder chamber and having a fourth piston that operates as a balance weight in a direction intersecting the spindle rotation center;
A hydraulic closed circuit connecting the third hydraulic cylinder chamber and the fourth hydraulic cylinder chamber;
Further comprising
The feed screw mechanism comprises a slider that is screwed into a male screw of the drive shaft,
The U-axis holder unit according to claim 4, wherein the rods of the first piston and the third piston are attached to the slider.   6. The U-axis holder unit according to claim 5, further comprising a biasing member that constantly biases the slider in a direction along the drive shaft.

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