JP2005103676A - Tool clamp mechanism for machine tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tool clamp mechanism of high reliability positively driving a wedge member with simpler constitution than conventional one while shortening a loop of clamping force transmission path. <P>SOLUTION: This tool clamp mechanism 10A pulls in a pull stud 5 backward in an axial direction by inserting the wedge member 11 between a flange face 5b of the pull stud 5 and a wedge receiving face 13 provided in a spindle 1 being positioned on the front end side of the spindle 1 rather than the flange face 5b. The wedge member 11 is provided with a clamping tapered face 11c abutting from the outer peripheral side in a radial direction of the spindle 1, and an unclamping tapered face 11d abutting from the center side in the radial direction. A draw bar 12 is provided with a wedge driving part 17 having a first tapered face 17 abutting on the clamping tapered face 11c from the outer peripheral side in the radial direction, and a second tapered face 17b abutting on the unclamping tapered face 11d from the center side in the radial direction. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a tool clamp mechanism for a machine tool that uses a wedge action to pull a pull stud of a tool holder into a main shaft.

  2. Description of the Related Art Conventionally, as a tool clamping mechanism of a machine tool, generally used is a mechanism in which a rear end portion of a pull stud inserted into a main shaft is gripped by a collet, and the collet is pulled behind the main shaft by a draw bar. The draw bar is biased rearward of the main shaft by a number of disc springs, and the pull stud is pulled rearward by the force of the disc springs. And the transmission path of the force to pull the pull stud (hereinafter referred to as the clamping force) has a contact portion between the taper shank of the tool holder and the taper hole of the main shaft as the front end, and greatly increases from there to the rear end of the draw bar. I draw a loop around.

  By the way, if the transmission path of the clamping force draws a loop, the chatter stability limit at the time of machining is lowered, and the stability of the spindle system against heavy cutting is lowered. Since the clamping force depends on the force of the disc spring, it is necessary to use a disc spring having a larger spring constant in order to prevent the clamp from loosening due to the pulling force acting on the tool. In this case, a large pulling force acts on the elongated drawbar, which is disadvantageous in terms of rigidity and strength.

In the clamping mechanism described in Patent Document 1, a flange surface of a pull stud inserted into the main shaft, and a wedge receiving portion of a collet opener fixed in the main shaft at a position closer to the front end of the main shaft than the flange surface In between, the wedge member (collet) is pushed in, and the pull stud is pulled behind the main shaft. According to such a clamping mechanism, the wedge member and the collet opener enter between the pull stud and the main shaft in a region in front of the pull stud (front end side of the main shaft) to form a transmission path for the clamping force. Therefore, it is possible to close the loop of the transmission path of the clamping force in a range in front of the pull stud.
JP-A-10-58210

However, the clamp mechanism described in Patent Document 1 described above includes the following problems.
(1) By causing the rear end portion of the wedge member to protrude rearward of the main shaft from the pull stud, bringing the protruding portion into contact with the tapered surface of the collet holder, and biasing the collet holder forward of the main shaft with a disc spring The wedge member is driven radially outward to release the pull stud. That is, when the draw bar moves forward and the wedge member is released, the collet holder receives the force of the disc spring and pushes the rear end portion of the wedge member forward, and the pushing force passes through the tapered surface and the wedge member. The wedge member moves to the radially outer peripheral side by acting as a force toward the radially outer peripheral side. In such a structure, the wedge member is pushed to the outer peripheral side in the radial direction at a position relatively far behind the main shaft with respect to the contact position between the pull stud and the wedge member, so that a moment acts on the wedge member. As a result, the wedge member may not be smoothly moved when releasing the pull stud.
(2) A cylinder case, which is attached to the tip of the draw bar and pushes the wedge member toward the radial center, is in line contact with the tapered surface of the outer periphery of the wedge member. Stress concentration tends to occur at the contact portion, and a large clamping force cannot be obtained.
(3) Since the movement of the wedge member toward the center in the radial direction and the movement toward the outer periphery in the radial direction are performed as separate parts, the number of parts increases, the assembly man-hour increases due to the complicated mechanism, and the reliability increases. Inconvenience such as decline is inevitable.

  Therefore, an object of the present invention is to provide a highly reliable tool clamping mechanism that can shorten the loop of the transmission path of the clamping force and can reliably drive the wedge member with a simpler configuration than the conventional one.

  The present invention will be described below. In order to facilitate understanding of the present invention, reference numerals in the accompanying drawings are appended in parentheses, but the present invention is not limited to the illustrated embodiment.

  The tool clamp mechanism (10A, 10B, 10C) according to the present invention has a flange surface (5b) of the pull stud (5) inserted into the main shaft by the operation of the draw bar (12) in the axial direction of the main shaft (1). And a wedge member (11) between the flange surface and a wedge receiving portion (13) provided in the main shaft positioned closer to the front end of the main shaft, and pulling the pull stud backward in the axial direction. In the tool clamp mechanism of the machine tool configured as described above, the wedge member can be brought into contact with the wedge contact portion (11c) capable of contacting from the outer peripheral side of the main shaft in the radial direction and from the center side in the radial direction. The unclamp contact portion (11d) is provided, and the draw bar has a first contact portion (17a) that contacts the clamp contact portion from the outer peripheral side in the radial direction, and the unclamp contact portion. Contact A wedge drive part (17) having a second contact part (17b) that comes into contact with the center in the radial direction is provided so as to be integrally movable forward and backward in the axial direction, and the clamp contact part and At least one of the first contact portions is configured to convert the movement of the draw bar toward one side in the axial direction of the main shaft into the movement toward the radial center of the wedge member by a wedge action. It is formed in a tapered surface inclined with respect to the direction, and at least one of the unclamping contact portion and the second contact portion causes the draw bar to move toward the other side in the axial direction of the main shaft. The above-described problem is solved by the fact that the wedge member is formed in a tapered surface inclined with respect to the axial direction so as to be converted into the movement of the wedge member toward the radially outer peripheral side by the wedge action.

  According to this clamp mechanism, when the draw bar is moved to one side in the axial direction of the main shaft, the first contact portion of the wedge drive portion pushes the clamp contact portion toward the radial center, thereby the wedge member. Is pushed between the flange surface of the pull stud and the wedge receiving portion on the main shaft side, and the pull stud is pulled rearward in the axial direction of the main shaft. Since the wedge member is located between the wedge receiving portion on the main shaft side and the flange surface of the pull stud, the loop drawn by the transmission path of the clamping force can be closed in a range ahead of the flange surface of the pull stud. Therefore, the chatter stability limit of the spindle system can be improved.

  On the other hand, when the draw bar is moved to the other side in the axial direction of the main shaft, the unclamping contact portion is pushed to the outer peripheral side in the radial direction by the second contact portion of the wedge driving portion, so that the wedge member is moved radially outward. It retracts to the side and the pull stud pull-in is released. As described above, the wedge member is driven to the outer peripheral side in the radial direction by the operation of the draw bar while the wedge driving portion provided on the draw bar is in contact with the wedge member, so that the wedge member is reliably retracted to the outer peripheral side in the radial direction. Can do.

  Furthermore, since the wedge member is driven to the center side and the outer peripheral side in the radial direction by the wedge drive unit at the tip of the draw bar, the number of parts is reduced and the mechanism is simplified. Therefore, the assembly man-hour is reduced and the reliability is improved.

  In the clamp mechanism of the present invention, the clamp contact portion and the first contact portion may be formed in a tapered surface shape that is inclined in the same direction with respect to the axial direction and in surface contact with each other. In this case, since the first contact portion of the wedge drive portion and the contact portion for clamping the wedge member are in surface contact, stress concentration is caused at the contact portion between the wedge member and the wedge drive portion when the pull stud is retracted. Can hardly occur and a large clamping force can be applied.

  The clamping contact portion and the unclamping contact portion may be disposed so as to face each other in a region on the outer peripheral side with respect to a contact position between the flange surface and the wedge member (FIGS. 2 and 6). . In this case, the wedge member can be compactly gathered on the outer peripheral side of the flange surface, and in the direction other than the radial direction by inputting the driving force for clamping or the driving force for unclamping from the draw bar to the wedge member. This is convenient for suppressing the movement of the wedge member.

  On the other hand, the abutting portion for clamping is disposed in a region on the outer peripheral side from the contact position between the flange surface and the wedge member, and the abutting portion for unclamping is disposed from a contact position between the flange surface and the wedge member. Also, it may be arranged rearward in the axial direction and closer to the center in the radial direction than the abutting portion for clamping (FIG. 5). In this case, the expansion of the wedge member toward the outer peripheral side in the radial direction can be suppressed. Therefore, it is suitable when the inner diameter of the main shaft is limited.

  At least one of the abutting portion for clamping and the first abutting portion converts the movement of the draw bar rearward in the axial direction into the movement of the wedge member toward the center in the radial direction by a wedge action. In addition, it may be formed in a tapered surface shape that deviates toward the outer peripheral side in the radial direction toward the rear in the axial direction (FIGS. 2 and 6). In this case, the pull stud can be pulled into the main shaft and restrained by moving the draw bar to the rear of the main shaft.

  Further, at least one of the abutting portion for clamping and the first abutting portion converts the motion of the draw bar forward in the axial direction into the motion of the wedge member toward the center in the radial direction by a wedge action. Thus, it may be formed in a tapered surface shape that deviates toward the outer peripheral side in the radial direction as it goes forward in the axial direction (FIG. 6). In this case, the pull stud can be pulled into the main shaft and restrained by operating the draw bar so as to push it forward of the main shaft.

  When both the clamp contact portion and the first contact portion are formed in a tapered surface, the inclination angle of the clamp contact portion and the first contact portion with respect to the axial direction of the main shaft is the pulling angle. Self-holding action that prevents the wedge member from slipping out to the outer peripheral side in the radial direction due to the input of force from the stud side is prevented by the frictional force acting between the clamping contact portion and the first contact portion. It is desirable that the range is set. In this case, after the wedge member is driven to the center in the radial direction and the pull stud is pulled into the main shaft, the pull stud is firmly tightened in the main shaft even if the clamping force is not continuously applied from the draw bar to the wedge member. It is possible to maintain the state of being drawn into. This improves the reliability and stability of the clamp.

  Further, the tool clamp mechanism (10A, 10B, 10C) of the present invention has a flange surface (5) of the pull stud (5) inserted into the main shaft by the operation of the draw bar (12) in the axial direction of the main shaft (1). 5b) and a wedge member (11) is inserted between the flange surface and the wedge receiving portion (13) provided in the main shaft so as to be closer to the front end of the main shaft, and the pull stud is moved rearward in the axial direction. In the tool clamp mechanism of a machine tool that is pulled into the wedge member, the wedge member has a taper surface for clamping (11c) facing the outer peripheral side in the radial direction of the main shaft, and faces the center side in the radial direction and An unclamping taper surface (11d) inclined in the same direction as the clamping taper surface is provided, and the draw bar has a first taper surface (17a) in surface contact with the clamping taper surface and a front surface. Wedge drive having unclamping tapered surface and the second tapered surface to surface contact with (17b) (17) may be as provided movably integrally with the forward and backward said axis.

  According to the clamping mechanism of the present invention, the wedge member is pushed between the wedge receiving portion of the main shaft and the flange surface of the pull stud so that the pull stud is pulled into the main shaft. It is possible to close the front end of the flange surface of the pull stud, thereby improving the chatter stability limit of the main spindle system. In addition, since the wedge member is driven at the time of clamping and unclamped by the wedge drive portion provided on the draw bar, the wedge member is moved radially inward and outward by the reciprocating motion of the draw bar in the axial direction. It is possible to increase the stability and reliability of the clamp mechanism by driving it reliably. Furthermore, since the wedge member is driven to the center side and the outer peripheral side in the radial direction by the wedge drive portion of the draw bar, the number of parts is reduced and the structure of the mechanism is simplified, so that the number of assembly steps is reduced. , Improve reliability. Furthermore, when the contact portion for clamping the wedge member and the first contact portion of the wedge drive portion are brought into surface contact, it is possible to suppress stress concentration on these contact portions and to give a larger clamping force. Become.

  FIG. 1 shows a first embodiment of a clamping mechanism of the present invention. As is well known, a tapered hole 2 is formed at the front end of the main shaft 1. The taper shank 4 of the tool holder 3 is inserted from the taper hole 2 and the pull stud 5 is pulled backward (to the left in FIG. 1) of the main shaft 1 by the clamp mechanism 10A. The tool holder 3 is attached to the main shaft 1 coaxially in close contact.

  The clamp mechanism 10 </ b> A includes a plurality of wedge members 11... 11 arranged so as to surround the axis of the main shaft 1 and a draw bar 12 for driving the wedge members 11 in the radial direction of the main shaft 1. The draw bar 12 is urged to the rear of the main shaft 1 by a spring means (not shown) such as a disc spring, and is pushed and driven in front of the main shaft 1 against the spring means by a driving means such as a hydraulic cylinder. The configuration related to the driving of the draw bar 12 may be the same as that of the conventional clamping mechanism.

  FIG. 2 shows details of the clamping mechanism 10A. However, FIG. 2 is a half sectional view with the axis AX of the main shaft 1 as a boundary, where (a) shows the time of clamping and (b) shows the time of unclamping. On the inner surface of the main shaft 1, a wedge receiving surface (wedge receiving portion) 13 is provided in front of the flange surface 5 b provided on the enlarged portion 5 a at the rear end of the pull stud 5. It is movable along the wedge receiving surface 13 in the radial direction. An escape groove 1a for receiving the wedge member 11 at the time of unclamping is formed on the inner peripheral surface of the main shaft 1. As shown in FIG. 3, a plurality of wedge members 11 are provided in the circumferential direction of the main shaft 1 (six in the figure). Spacers 14... 14 are arranged between the wedge members 11. The wedge members 11... 11 are bundled in a ring shape by a holding ring 15 attached to the outer periphery thereof. The wedge member 11, the spacer 14, and the holding ring 15 constitute a clamp ring 16. 3A is a sectional view in the axial direction of the clamp ring 16, FIG. 3B and FIG. 3C are front views from the axial direction, FIG. 3B is when clamping, and FIG. 3C is when unclamping. The state of each is shown. At the time of unclamping, a center hole 16 a having a size through which the enlarged portion 5 a of the pull stud 5 can pass is formed at the center of the clamp ring 16. The holding ring 15 is made of an elastic material such as rubber or a coil spring.

  As shown in FIGS. 2A and 2B, the wedge member 11 has a tapered tool holding surface 11 a in surface contact with the flange surface 5 b of the pull stud 5 and a constraining surface in surface contact with the wedge receiving surface 13. 11b. The wedge receiving surface 13 is orthogonal to the axis AX of the main shaft 1, and the tool holding surface 11 a is tapered like a flange surface 5 b of the pull stud 5 that deviates toward the front of the main shaft 1 from the radially outer side toward the center. Is formed. Therefore, when the wedge member 11 is pushed toward the radial center along the wedge receiving surface 13, the flange surface 5b and the tool holding surface 11a come into contact with each other, and the pull stud 5 is drawn rearward of the main shaft 1.

  Further, on the outer peripheral side of the tool holding surface 11 a of the wedge member 11, a clamping taper surface (clamping contact portion) 11 c facing the radial outer peripheral side of the main shaft 1, and the radial center side of the main shaft 1 are provided. And an unclamping taper surface (unclamp contact portion) 11d facing each other is formed so as to face each other. These taper surfaces 11c and 11d are inclined so as to deviate toward the outer peripheral side in the radial direction toward the rear in the axial direction of the main shaft 1. The inclination angles α of the tapered surfaces 11c and 11d with respect to the axis AX of the main shaft 1 are the same. However, if the wedge member 11 can move sufficiently outward in the radial direction during unclamping, the inclination angle α of the taper surfaces 11c and 11d does not necessarily have to be set equal, and the inclination angle α of the unclamping taper surface 11d is set to be the taper surface 11c for clamping. It may be set larger than the inclination angle α.

  On the other hand, a wedge driving portion 17 for driving the wedge member 11 in the radial direction is integrally provided at the tip of the draw bar 12. The wedge drive portion 17 includes a first taper surface (first contact portion) 17a that abuts against the clamping taper surface 11c of the wedge member 11 from the radially outer side, and an unclamping taper surface 11d from the radial center side. A second tapered surface (second abutting portion) 17b that abuts is provided. The inclination angles of the first taper surface 17a and the second taper surface 17b with respect to the axis AX are the same as the inclination angles α of the taper surfaces 11c and 11d of the wedge member 11. Thereby, the 1st taper surface 17a can surface-contact with the taper surface 11c for clamping, and the 2nd taper surface 17b can surface-contact with the taper surface 11d for unclamping.

  The wedge drive unit 17 can be provided by cutting the tip of the draw bar 12. Alternatively, the wedge drive unit 17 is first manufactured as a separate part from the draw bar 12, and the wedge drive unit 17 is fixed to the tip of the draw bar 12 using a fixing means such as a screw. It may be integrated with the draw bar 12. In short, the wedge drive unit 17 only needs to be able to move integrally with the draw bar 12 in the direction of the axis AX of the main shaft 1.

  In the clamp mechanism 10A configured as described above, when the draw bar 12 is driven forward of the main shaft 1, the second taper surface 17b and the unclamp taper surface 11d come into contact with each other as shown in FIG. 11 is driven radially outward. As a result, the center hole 16a of the clamp ring 16 expands, and the enlarged portion 5a of the pull stud 5 can be inserted and removed. On the other hand, when the draw bar 12 is retracted to the rear of the main shaft 1, the wedge member 11 is driven to the radial center side because the first tapered surface 17a pushes the clamping tapered surface 11c as shown in FIG. The Thereby, the wedge member 11 enters between the flange surface 5b and the wedge receiving surface 13, and the pull stud 5 is pulled backward. At this time, the loop LP of the clamping force is closed in a region in front of the main shaft 1 with respect to the pull stud 5. Therefore, the chatter stability limit is improved.

  FIG. 4 is a graph showing the relationship between the force increase rate defined as the ratio (Faz / Fe) between the pulling force 12 pulling force Faz (see FIG. 2A) and the drawbar 12 pulling force Fe, and the inclination angle (wedge angle) α. The result which calculated | required the relationship by the calculation is shown. As is clear from this figure, when the inclination angle β of the flange surface 5b of the pull stud 5 with respect to the direction orthogonal to the axis AX of the main shaft 1 is kept constant, the power increase rate can be increased as the inclination angle α is smaller. . In particular, it can be seen that the rate of increase in power can be made relatively large by setting the inclination angle α to 20 ° or less, preferably 15 ° or less.

  Furthermore, the inclination angle α is the self-holding action of the wedge member 11, that is, even if an external force is applied between the flange face 5b and the tool holding face 11a from the pull stud 5 side, the clamping tapered face 11c and the first tapered face 17a. It is more preferable to set the angle within a range (for example, 5 °) in which the action of maintaining the clamped state is obtained without the wedge member 11 coming out due to the frictional force therebetween.

  The wedge receiving surface 13 may be formed as a tapered surface inclined in the opposite direction to the flange surface 5b, that is, a tapered surface that is deviated toward the rear of the main shaft 1 toward the center in the radial direction. When the wedge receiving surface 13 is inclined as described above, the rotation of the wedge member 11 due to the moment Mc (FIG. 2) generated in the wedge member 11 due to the pushing force by the first tapered surface 17 a can be suppressed. If such a rotational moment Mc is left unattended, the wedge member 11 is inclined in combination with the centrifugal force acting on the wedge member 11 as the main shaft 1 rotates, and the force increase rate tends to decrease. Therefore, a countermeasure for suppressing the inclination of the wedge member 11 due to the rotational moment Mc is particularly effective when dealing with high-speed rotation. A similar effect can be obtained for the rotational moment Mc by reducing the inclination angle β (for example, about 5 °).

  FIG. 5 is a half sectional view similar to FIG. 2 regarding the clamp mechanism 10B according to the second embodiment of the present invention, wherein (a) shows a state at the time of clamping and (b) shows a state at the time of unclamping. In the clamp mechanism 10B, the unclamping taper surface 11d of the wedge member 11 is formed at a position rearward in the axial direction of the main shaft 1 with respect to the tool holding surface 11a and on the radial center side of the clamping taper surface 11c. This is different from the clamp mechanism 10A in FIG. The position of the second tapered surface 17b of the wedge driving unit 17 is also changed in accordance with the unclamping tapered surface 11d. According to such a configuration, expansion of the wedge member 11 toward the radially outer peripheral side of the main shaft 1 can be suppressed, and processing of the relief groove 1a (see FIG. 2) on the inner periphery of the main shaft 1 can be made unnecessary. Further, in the example of FIG. 5, a holding ring 18 for restraining the outer periphery of the wedge member 11 on the wedge receiving surface 13 is provided on the inner periphery of the main shaft 1 in order to prevent rattling of the wedge member 11 during unclamping. ing. Since almost no load is applied to the holding ring 18, the holding ring 18 may be formed of a material having low rigidity such as resin. As a method for attaching the holding ring 18, for example, a method in which the holding ring 18 is elastically deformed and inserted to the attachment position in the main shaft 1 and the holding ring 18 is restored to the original shape at the attachment position can be used.

  Regarding the parts other than the above, the clamp mechanism 10B of FIG. 5 is the same as the clamp mechanism 10A of FIG.

  FIG. 6 is a half sectional view similar to FIG. 2 relating to the clamping mechanism 10C according to the third embodiment of the present invention, where (a) shows the time of clamping and (b) shows the time of unclamping. This clamping mechanism 10C sets the relationship between the direction of movement of the draw bar 12 and the direction of movement of the wedge member 11 by setting the inclination directions of the taper surface 11c for clamping and the taper surface 11d for unclamping to be opposite to those in FIG. It has been changed. That is, in the clamp mechanism 10C of FIG. 6, the taper surface 11c for clamping and the taper surface 11d for unclamping are both formed in a tapered surface shape that is displaced toward the outer peripheral side in the radial direction toward the front in the axial direction of the main shaft 1. Yes. For this reason, the wedge member 11 is pushed in by the forward movement of the draw bar 12 in the axial direction and the pull stud 5 is pulled backward, and the wedge member 11 moves to the outer peripheral side in the radial direction by the backward movement of the draw bar 12 in the axial direction. Thus, pull-in of the pull stud 5 is released. Regarding the parts other than the above, the clamping mechanism 10C in FIG. 6 is the same as the clamping mechanism 10A in FIG. According to the structure of FIG. 6, as the draw bar 12 is driven forward, the contact area between the first taper surface 17a of the wedge drive unit 17 and the taper surface 11c for clamping increases as the clamp progresses. Therefore, the contact area between the wedge member 11 and the wedge drive unit 17 in the clamped state can be ensured larger than in the examples of FIGS.

  In FIG. 6, the clamping taper surface 11c and the unclamping taper surface 11d are provided so as to face each other. However, similarly to FIG. 5, the unclamping taper surface 11d is located behind the tool holding surface 11a and the clamping taper. You may provide in the radial direction center side rather than the surface 11c.

  The present invention is not limited to the above embodiment, and may be implemented in various forms. For example, instead of a configuration in which the clamping contact portion and the first contact portion are formed on the tapered surfaces 11c and 17a having the same inclination angle and brought into surface contact, either one of the contact portions is formed in a protruding shape or the like. The contact portion may be brought into line contact. The unclamping contact portion and the second contact portion are also formed on the tapered surfaces 11d and 17b so as to be in surface contact with each other, and either one of the contact portions is formed in a protruding shape or the like. The contact portion may be brought into line contact. However, it is desirable that the clamping contact portion and the first contact portion are brought into surface contact as much as possible to avoid stress concentration.

  In the present invention, the tapered hole of the main shaft may be based on a standard that causes a self-holding action such as HSK or NC5, or may be based on a standard that does not cause a self-holding action such as a BT shank. When the main shaft taper hole in which the self-holding action occurs is adopted, the inclination angle β of the pull stud may be increased.

The axial direction sectional view of the clamp mechanism of a 1st embodiment of the present invention. The figure which shows the detail of the clamp mechanism of FIG. The figure which shows the structure of the clamp ring used with the clamp mechanism of FIG. The figure which shows the relationship between inclination-angle (alpha) and (beta) by the clamp mechanism of FIG. 2, and a power increase rate. The figure which shows the detail of the clamp mechanism of 2nd Embodiment. The figure which shows the detail of the clamp mechanism of 3rd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Main axis | shaft 2 Tapered hole 3 Tool holder 4 Tapered shank 5 Pull stud 5b Flange surface 10A, 10B, 10C Clamp mechanism 11 Wedge member 11a Tool holding surface 11b Restraint surface 11c Clamp taper surface (clamp contact part)
11d Taper surface for unclamping (unclamp contact part)
12 Drawbar 13 Wedge receiving surface (wedge receiving part)
14 Spacer 15 Holding ring 16 Clamp ring 17 Wedge drive part 17a 1st taper surface (1st contact part)
17b 2nd taper surface (2nd contact part)
18 Retaining ring AX Spindle axis

Claims (8)

By the movement of the draw bar in the axial direction of the main shaft, the flange surface of the pull stud inserted into the main shaft and the wedge receiving portion provided in the main shaft positioned closer to the front end of the main shaft than the flange surface In a tool clamp mechanism of a machine tool in which a wedge member is inserted and the pull stud is pulled back in the axial direction,
The wedge member is provided with a clamp contact portion that can be contacted from the outer peripheral side in the radial direction of the main shaft, and an unclamp contact portion that can be contacted from the center side in the radial direction,
The draw bar has a first contact portion that comes into contact with the clamp contact portion from the radially outer side and a second contact that comes into contact with the unclamp contact portion from the radial center side. A wedge driving portion having a contact portion is provided so as to be integrally movable forward and backward in the axial direction;
At least one of the clamp contact portion and the first contact portion converts the movement of the draw bar toward one side in the axial direction into the motion toward the radial center of the wedge member by a wedge action. Formed into a tapered surface inclined with respect to the axial direction,
At least one of the unclamping contact portion and the second contact portion causes the movement of the draw bar toward the other side in the axial direction to move the wedge member toward the radially outer peripheral side by a wedge action. It is formed in a tapered surface inclined with respect to the axial direction so as to be converted,
A tool clamping mechanism for machine tools.   2. The tool according to claim 1, wherein the abutting portion for clamping and the first abutting portion are formed in tapered surfaces that are inclined in the same direction with respect to the axial direction and are in surface contact with each other. Clamp mechanism.   2. The clamp contact portion and the unclamp contact portion are disposed so as to face each other in a region on the outer peripheral side with respect to a contact position between the flange surface and the wedge member. Or the tool clamp mechanism of 2.   The clamp contact portion is disposed in a region on the outer peripheral side of the contact position between the flange surface and the wedge member, and the unclamp contact portion is positioned above the contact position between the flange surface and the wedge member. 3. The tool clamping mechanism according to claim 1, wherein the tool clamping mechanism is disposed rearward in the axial direction and closer to the center in the radial direction than the abutting portion for clamping.   At least one of the abutting portion for clamping and the first abutting portion converts the movement of the draw bar rearward in the axial direction into the movement of the wedge member toward the center in the radial direction by a wedge action. The tool clamping mechanism according to any one of claims 1 to 4, wherein the tool clamping mechanism is formed in a tapered surface that is displaced toward the outer periphery in the radial direction toward the rear in the axial direction.   At least one of the abutting portion for clamping and the first abutting portion converts the movement of the draw bar forward in the axial direction into the movement of the wedge member toward the center in the radial direction by a wedge action. The tool clamp mechanism according to any one of claims 1 to 4, wherein the tool clamp mechanism is formed in a tapered surface shape that deviates toward the outer peripheral side in the radial direction toward the front in the axial direction.   The inclination angle of the abutting portion for clamping and the first abutting portion with respect to the axial direction of the main shaft is determined so that the wedge member is pulled out to the outer peripheral side in the radial direction by the input of force from the pull stud side. The tool clamping mechanism according to claim 2, wherein the tool clamping mechanism is set in a range in which a self-holding action that is blocked by a frictional force acting between the contact portion and the first contact portion is generated. By the movement of the draw bar in the axial direction of the main shaft, the flange surface of the pull stud inserted into the main shaft and the wedge receiving portion provided in the main shaft positioned closer to the front end of the main shaft than the flange surface In a tool clamp mechanism of a machine tool in which a wedge member is inserted and the pull stud is pulled back in the axial direction,
The wedge member has a clamp taper surface facing the outer peripheral side in the radial direction of the main shaft, and an unclamp taper surface facing the center side in the radial direction and inclined in the same direction as the clamp taper surface. Provided,
In the draw bar, a wedge driving portion having a first taper surface in surface contact with the clamping taper surface and a second taper surface in surface contact with the unclamping taper surface is integrally moved forward and rearward in the axial direction. A tool clamping mechanism of a machine tool, wherein the tool clamping mechanism is provided as possible.

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