JPH09290302A - Main spindle device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain the deterioration of support rigidity to the radius direction of a tool, even if a main spindle main body is rotated by a high speed, relating to the main spindle device. SOLUTION: When a main spindle main body 30 is rotated, a centrifugal force is applied to a main spindle main body 30, a taper part 14 and a tool holder 12 respectively. In this time, the taper part 14 is expanded in an arrow mark D4 direction to the outside for the tool holder 12 relatively. When the taper part 14 is expanded to the outside, it is moved in an arrow mark D6 direction by a coned disc spring 24 by an expanded amount. Therefore, in the tool side of the taper part 14 (an opening edge side), a clearance between the tool holder 12 and the taper part 14 is not generated but the taper part 14 is pressed by an amount by which a clearance is produced and the clearance is buried. Thus, even if the main spindle main body 30 is rotated by a high speed, the support rigidity to the radius direction of the tool 10 (tool holder 12) is not deteriorated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spindle device, and more particularly to a technique for firmly attaching a tool holder to a spindle body during high speed rotation.

[0002]

2. Description of the Related Art A conventional spindle device 210 will be described with reference to FIG. In FIG. 17, the main spindle body 206 is provided with a tapered concave portion 206a. The tool holder 202 is provided with a tapered convex portion 202a that is fitted into the concave portion 206a. Spindle body 2
A draw bar 208 penetrates along the axis 06, and the draw bar 208 is urged by an elastic body 212 toward the non-tool side (right side in the drawing). The tool 200 is fixed to the tool holder 202. According to this structure,
The tool holder 202 is pulled to the side opposite to the tool by the draw bar 208, the convex portion 202a is inserted into the concave portion 206a and fitted into each other, and the tool holder 202 is attached to the main spindle body 206.

When the main spindle body 206 is rotated at high speed in this state, the concave portion 206a spreads outward relative to the convex portion 202a due to centrifugal force. At this time, the concave portion 206a becomes wider as it approaches the opening edge 206b. When the recess 206a is expanded outward in this manner, the drawbar 208
Thereby, the tool holder 202 is deeply drawn into the recess 206a. As a result, the axial position of the tool 200 changes. To solve this problem, a technique described in Japanese Patent Laid-Open No. 7-223146 has been proposed, and the spindle main body 2 can be used depending on the rotation speed.
The position of the tool 200 in the axial direction is corrected to maintain the position of the tool 200 in the axial direction at a constant position against the fluctuation of the rotation speed.

However, even with this technique, the recess 206 is formed.
It has not been possible to deal with the problem that a spreads wider near the opening edge 206b. That is, the recess 20
Even when the tool holder 202 is deeply inserted into the concave portion 206a when 6a spreads relatively outward with respect to the convex portion 202a, the radial direction between the concave portion 206a and the convex portion 202a is increased in the vicinity of the opening edge 206b. It is inevitable that the clearance will occur. Therefore, the problem that the support rigidity of the tool 200 in the radial direction is reduced has not been solved. Further, as described in JP-A-6-226516, when a tool is fixed to the tool holder by covering the outer periphery of the tool holder with a high tension nut, the opening edge on the tool holder side is prevented from expanding outward. There are also things to try.

[0005]

SUMMARY OF THE INVENTION A first object of the present invention is to realize a spindle device capable of suppressing a decrease in supporting rigidity in a radial direction of a tool holder even when the spindle body is rotated at a high speed. is there.

On the other hand, when the axial position of the tool is important, the technique disclosed in Japanese Patent Laid-Open No. 7-223146 is certainly an effective method. However, in that method, the axial position of the main spindle body must be finely controlled according to the rotation speed. A second object of the present invention is to realize a spindle device that can prevent axial displacement of a tool with respect to a spindle body when axial position is important.

[0007]

According to a first aspect of the present invention, one of the tool holder and the spindle main body is provided with a tapered concave portion, and the other is provided with a convex portion to be fitted into the concave portion. In the spindle device in which the tool holder is attached to the main spindle body by inserting the convex portion into the concave portion, the vicinity of the opening edge of the concave portion is relatively outside with respect to the convex portion due to the high speed rotation of the main spindle body. Is characterized in that a supplementary means is added to fill the clearance generated between the vicinity of the opening edge of the recess and the projection. According to the invention as set forth in claim 1, the concave portion expands outward relative to the convex portion due to centrifugal force, and a clearance is apt to be generated in the radial direction between the concave portion and the convex portion in the vicinity of the opening edge. However, the existence of the filling means prevents the occurrence of clearance. Therefore, even if the main spindle body is rotated at high speed, the supporting rigidity of the tool in the radial direction does not decrease, and the machining accuracy can be maintained.

[0008]

In this case, filling means may be provided on the convex portion, and the filling means may be deformed outward by heat or centrifugal force to fill the clearance. According to the present invention, the clearance is filled with the filling means deformed by heat or centrifugal force. In this way, the supporting rigidity in the radial direction of the tool can be maintained without using another power source, so that the machining accuracy can be maintained.

Further, the means for supplementing the elastic force, centrifugal force,
It is also possible to use a member that is displaced by any one of inertial forces to fill the clearance. According to the present invention, the filling means is displaced by any one of the elastic force, the centrifugal force and the inertial force to fill the clearance. In this way, the supporting rigidity in the radial direction of the tool can be maintained without using another power source, so that the machining accuracy can be maintained.

Further, it is desirable to provide a restraining member between the tool holder and the main spindle body for restraining the relative movement of the two in the axial direction. According to the present invention, the axial movement of the tool holder is constrained by the constraining member. In this way, movement of the tool holder in the axial direction is prohibited,
It is possible to maintain machining accuracy in the axial direction.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. [Embodiment 1] First, in Embodiment 1, an example in which a taper portion that can be displaced in the axial direction is provided in a main spindle body will be described with reference to FIGS. 1 and 2. Here, in FIG. 1, a taper portion 14 which is displaceable in the axial direction on the main spindle body 30.
The spindle device provided with. FIG. 2 shows the tapered portion 1
4 shows the operation of No. 4.

In FIG. 1, the spindle device 22 is roughly divided into a spindle body 30, a spindle head 18, a cylinder 38 and a tool holder 12. A taper portion 14 is attached to the main spindle body 30 so as to be displaceable in the axial direction. The spindle head 18 rotatably supports the spindle body 30 via a bearing 16. Spindle body 30
Between the spindle head 18 and the spindle head 20
Is provided. The built-in motor 20 is composed of a stator 20a provided on the spindle head 18 side and a rotor 20b provided on the spindle body 30 side. The drawbar 26 is movably provided along the axis of the main spindle body 30, and a grip portion 26a provided at one end of the drawbar 26 grips one end 12a of the tool holder 12 and the other end of the drawbar 26 contacts the push bar 32. It is accessible.

The draw bar 26 is biased toward the opposite tool side (right side in the drawing) by a counter spring 28. The push bar 32 is connected to the piston 40 of the cylinder 38,
It is provided so as to be movable in the axial direction with the operation of the piston 40. The piston 40 is provided with an O-ring 36, and is urged toward the opposite side of the tool by a spring 34. The tool holder 12 is provided with a fitting bar 12a for fitting in the grip portion 26a.
Are fixed with bolts or the like.

A taper portion 14 is provided at the left end of the main spindle body 30.
Is assembled. The slide surface 14a of the taper portion 14 slides on the slide surface 30a on the main spindle body 30 side to be displaceable along the axis, and the taper portion 1
No. 4 and the main shaft body 30 are not tilted. The taper portion 14 is biased toward the tool side (left side in the drawing) by a countersunk spring 24. Tapered part 14
A tapered recessed portion 14b is formed in the. On the other hand, the tool holder 12 has a tapered recess 14
The convex part 12b fitted in b is formed. The concave portion 14b and the convex portion 12b each have a bell-shaped curved surface. Here, the bell-shaped curved surface means that when the tapered portion 14 spreads outward, when it is translated in the axial direction,
It is a shape that almost matches the curved surface before it spreads to the outside.

The elastic force of the spiral spring 28 is larger than that of the spiral spring 24. Therefore, unless the piston 40 of the cylinder 38 is moved to the tool side, the draw bar 26 is at the right dead center position. Even if the draw bar 26 is at the right dead center position, the draw bar 26 and the push bar 32 do not contact each other unless the piston 40 is moved to the tool side. Further, the tapered portion 14 is pressed against the tool holder 12 by the elastic force of the belleville spring 24. As a whole, the concave portion 14b of the taper portion 14 that rotates together with the main spindle body 30
The tool holder 12 is attached to the main spindle body 30 by inserting and fitting the convex portions 12 b of the tool holder 12 into. At this time, the tool holder 12 is constrained by the draw bar 26 located at the right dead center position and cannot be displaced in the axial direction. On the other hand, the tapered portion 14 is
It is displaceable in the axial direction on the front side of 0 (left side in FIG. 1) and restrains the tool holder 12 except in the axial direction.
At the time of unclamping, the piston 4 is resisted against the spring 34.
0 is pressed to the tool side (direction of arrow D2) by hydraulic pressure (or pneumatic pressure), and the push bar 32 is moved to the tool side and brought into contact with the other end of the draw bar 26. When the piston 40 is further moved to the tool side, the draw bar 26 moves to the tool side against the spring 28, and when the left dead point is reached, the grip portion 26a releases the tool holder 12.

To rotate the main shaft body 30, the built-in motor 20 is driven (specifically, the stator 20a).
Drives the rotor 20b). As the number of rotations of the main spindle body 30 increases, the main spindle body 30, the tapered portion 14,
A centrifugal force acts on each of the tool holders 12. At this time, the taper portion 14 spreads outward relative to the tool holder 12 in the direction of arrow D4 in FIG. When the taper portion 14 is displaced toward the tool holder 12 side and spreads outward,
The taper portion 14 is displaced in the direction of arrow D6 (that is, the tool side) by the force of the countersunk spring 24 accordingly. For this,
On the tool side of the tapered portion 14 (that is, on the opening edge side), no clearance is generated between the tool holder 12 and the tapered portion 14, and the tapered portion 14 is displaced by the amount that the clearance is about to be generated to fill the clearance. .

Thus, the tool holder 12 is the drawbar 2
The position of the tool tip in the axial direction can be maintained constant without being pulled deeply by 6. Further, the tapered portion 14 moves relative to the tool holder 12 to fill the clearance generated by the high speed rotation of the main spindle body 30. Therefore, by maintaining the contact pressure at the contact portion between them, the supporting rigidity of the tool holder 12 in the radial direction can be maintained. Therefore,
Even if the number of rotations of the main spindle body 30 changes, the tip position of the tool 10 does not change in the axial direction or the radial direction, and the machining accuracy can be maintained.

Instead of the structure in which the drawbar 26 is movable along the axial direction, the drawbar 26 may be fixed to the main spindle body 30 by a restraint member such as a bolt 42 as shown in FIG. Therefore, the cylinder 38, the piston 40, etc. as a means for moving the draw bar 26 in the axial direction are not necessary. In this configuration, the draw bar 26 is prevented from moving relative to the main spindle body 30, and the taper portion 14 is displaced toward the tool holder 12 side by the elastic force of the flat spring 24 so that the contact area of the contact portion is maintained substantially constant. It Thus, the movement of the tool holder 12 along with the displacement of the taper portion 14 is prohibited, so that the tool 10
The axial direction and the radial direction of are fixed. Therefore, the processing accuracy can be maintained more reliably. in this case,
When the tool holder 12 is replaced, the bolt 42 and the like are removed to free the draw bar 26.

Next, a method for exchanging (clamping / unclamping) the tool holder 12 will be described with reference to FIGS.
Will be described with reference to. Here, FIG. 12 shows the spindle device in an unclamped state, and FIG. 13 shows the spindle device in a clamped state. FIG. 14 shows the configuration of another taper portion. 15 and 16 show the configuration of the unclamping means.

First, the tool holder 12 is clamped as follows. That is, as shown in FIG. 12, the draw bar 26 is fixed to the main spindle body 30, and the tool holder 1
2 is in an unclamped state. The taper portion 14c is attachable to and detachable from the main spindle body 30, and is biased toward the tool side (left side in the drawing) by the spring spring 24. The taper portion 14c is moved to the tool side by the elastic force of the flat spring 24, and the grip portion 26a of the draw bar 26 is moved to the tool holder 12.
Grips one end 12a of the. In this way, the axial position of the tool holder 12 is fixed. When the tapered portion 14c further moves to the tool side, the tapered portion 14c and the tool holder 1
The two come into close contact with each other. In this way, the radial position of the tool holder 12 is fixed. FIG. 13 shows a state in which the tool holder 12 is clamped.

Next, the unclamping of the tool holder 12 is performed as follows. That is, in the clamped state shown in FIG. 13, the tapered portion 14c is moved to the opposite tool side (right side in the drawing) against the elastic force of the flat spring 24. By the movement of the taper portion 14c, the close contact state between the taper portion 14c and the tool holder 12 is released first, and then the grip portion 26a of the draw bar 26 is opened to open the one end 12a of the tool holder 12. Thus, the tool holder 12 is shown in FIG.
The unclamped state shown in 2 is obtained.

With the above arrangement, the tool holder 12 can be replaced from the tool side (that is, the front surface of the spindle). Therefore, the number of movable parts inside the main spindle body 30 can be minimized, so that the main spindle body 30 can be rotated in a well-balanced manner. Further, as shown in FIG.
A configuration may be adopted in which b is attached and fixed to the spindle main body 30 from the tool side. In this case, since there is no portion penetrating the central portion of the main spindle body 30, the rigidity of the main spindle body 30 itself can be increased.

In general equipment such as machine tools,
Many have a working table on the tool side. In this case, the tool holder can be replaced more efficiently by the relative movement between the spindle device and the machining table. For example, as shown in FIG. 15, the column 94 provided with the spindle device 22 is movable in the direction of arrow D22, and / or the processing table 90 is indicated by arrow D20.
Some can move in any direction. In this case, the processing table 90 is provided with a replacement auxiliary member 92. The replacement auxiliary member 92 is formed of a ring, a protrusion, or the like, and has a function of pushing the tapered portion 14c against the elastic force of the flat spring 24. With this configuration, the spindle device 2
The tool holder 12 can be replaced by moving the two or / and the working table 90 relatively. Therefore, replacement of the tool holder 12 does not require another power source.

Similarly, as shown in FIG. 16, the ATC hand 96 may be provided with a replacement auxiliary member 92. In this case, the taper portion 14c is pushed in by moving the ATC hand 96 in the direction of arrow D24, and the tool holder 12 is freed. Further, by operating the claw 98 of the ATC hand 96 in the direction of arrow D26, the tool holder 12 is grasped and pulled out,
Can be unclamped. The tool holder 12 can be clamped by the reverse operation. Further, the tool holder 12 can be automatically replaced by continuously performing the unclamping and the clamping. The replacement auxiliary member 92 may be provided not only on the processing table 90 and the ATC hand 96 but also on a dedicated drive source provided in general equipment such as a machine tool.

[Second Embodiment] Next, in a second embodiment, an example of filling a clearance by utilizing thermal deformation will be described with reference to FIGS. Here, FIG.
Shows a spindle device provided with a heat source on the convex side. In FIG.
The contact surface pressure between the tool holder and the spindle body is shown. FIG.
Shows an example in which a heat transfer member is provided in place of the heater of the spindle device shown in FIG. The structures of the cylinder 38, the piston 40, etc. for pushing out the drawbar 66 are the same as those in the first embodiment, and therefore, the same reference numerals are given and the description thereof is omitted.

In FIG. 4, the spindle device 60 is roughly divided into a spindle body 68, a spindle head 56, a cylinder 38 and a tool holder 52. The spindle head 56 rotatably supports a spindle body 68 via a bearing 54. A built-in motor 58 is provided between the spindle head 56 and the spindle body 68.
A draw bar 66 is provided along the axis of the main shaft body 68 so as to be movable in the axial direction. A grip portion 66a provided at one end of the draw bar 66 grips one end of the tool holder 52, and the other end thereof has a push bar 32. Can be contacted with. The drawbar 66 is biased toward the opposite tool side by the countersunk spring 64. Note that the draw bar 66 and the push bar 32 do not come into contact with each other during normal clamping.

Further, a convex taper portion 68a is provided on the tool side of the main spindle body 68. The taper part 6
8a is formed of a material that easily expands when heated, and has a truncated cone shape with the tool side as an apex.
The substantially central portion of the tapered portion 68a is the grip portion 66a.
Is located, and the heater 62 (heat source) is arranged on the main shaft main body 68 near the convex tapered portion 68a. The tool holder 52 is formed in a concave shape so as to fit and fit so as to cover the entire convex tapered portion 68a, and a cooling fin 52a for heat dissipation is provided on the outer peripheral surface thereof. With this cooling fin 52a, the tool holder 52 has a tapered portion 68a (that is, the main spindle body 6).
Since it is maintained at a temperature lower than that of 8), thermal expansion does not easily occur. The tool 50 is fixed to the tool holder 52 with bolts or the like. When the rotation of the main spindle body 68 is stopped, the tip end surface 68c of the tapered portion 68a is brought into contact with the concave bottom surface 52c of the tool holder 52 by the elastic force of the countersunk spring 64, and the tool holder 52 is attached to the main spindle body 68. Therefore, the taper portion 68a and the taper surface of the tool holder 52 are fitted together, and the tip surface 68c and the bottom surface 5 are fitted together.
Two-sided restraint is realized by contact with 2c.

When the spindle main body 68 is rotated by the built-in motor 58, the tool holder 52 expands in the direction of arrow D10 by centrifugal force, as shown in FIG. on the other hand,
The convex tapered portion 68 a is heated by the heater 62. The heating causes the tapered portion 68a to thermally expand in the direction of the arrow D10, so that the clearance that is likely to occur between the tapered portion 68a and the tool holder 52 is filled. Therefore, the contact area of the contact portion between the tapered portion 68a and the tool holder 52 is maintained substantially constant, and the contact pressure is maintained. In this example, the concave bottom surface 52c of the tool holder 52 and the tip surface 68 of the taper portion 68a are
Due to the surface restraint with c, the drawbar 66 is not pulled to the opposite tool side by the countersunk spring 64, and the support rigidity in the radial direction of the tool holder 52 can be maintained while maintaining the two-face restrained state. Therefore, even when the main spindle body 68 rotates at a high speed, the tool tip position does not change in the radial direction or the axial direction as in the case of the low speed rotation, and the machining accuracy can be maintained.

According to this embodiment, even if the concave portion of the tool holder 52 expands outward with the rotation of the main spindle body 68, the convex tapered portion 68a (complementing means) is deformed to the outside and both of them are expanded. Fill in the clearance that is about to occur. In this way, since the supporting rigidity of the tool holder 52 in the radial direction is maintained without using another power source, the machining accuracy can be maintained.

Although the heater 62 is provided in the main spindle body 68 in the above embodiment, the main spindle body 68 can be easily heated to 100 by the heat generated by the built-in motor 58.
May reach ° C. When the convex tapered portion 68a can be sufficiently deformed by this heat, the heater 62 is unnecessary. Further, the temperature of the entire main body 68 of the spindle is increased by the built-in motor 58 and the heater 62, but in this case, it is necessary to cool the part which is troubled if the temperature becomes high. Therefore, as shown in FIG. 6, passages 56a and 66b communicating with a portion requiring cooling may be provided and cooled with air (or cooling water or the like). In FIG. 6, the heater 62
Instead of this, a member having good heat conduction (for example, a copper rod or a heat pipe) is embedded in the main spindle body 68. In this way, the built-in motor 58 is attached to the convex taper portion 68a.
By transmitting the heat generated in the above, the heat can be sufficiently deformed so as to fill the clearance.

FIG. 7 shows an example in which a power supply mechanism for the heater 62 is provided in the main spindle body 68. Specifically, the heater 6
A coil 70 to be connected to the main shaft main body 68 is provided in the main body 68 and a permanent magnet 72 is provided in the main spindle head 56. According to this structure, when the main shaft main body 68 is rotated, the magnetic flux of the permanent magnet 72 is cut by the coil 70, and power is generated and power can be supplied. An electromagnet may be used instead of the permanent magnet 72, or the magnetic field of the built-in motor 58 may be used to omit the permanent magnet 72. Also,
When the stator 58a of the built-in motor 58 is an electromagnet and the rotor 58b is a coil, a part of the built-in motor 58 is used as it is for the heater 6
It is also possible to supply power to 2.

[Other Embodiments] In the spindle device of the present invention, the structure, shape, size, material, number, arrangement, operating conditions, etc. other than those described above are limited to those in the above embodiment. Not a thing. For example, each of the following modes to which the above-described embodiment is applied can be implemented. (1) In the first embodiment, the contact portion between the tool holder 12 and the tapered portion 14 is formed in a bell-shaped curved surface, but the area of the contact portion changes even if the tapered portion 14 is displaced in the axial direction, that is, the tool holder 12 side. It may be formed by another curved surface that does not exist. Even in this case, since the contact area does not change even if the taper portion 14 is displaced, the supporting rigidity of the tool holder 12 in the radial direction can be maintained. Therefore,
Since the clearance generated between the tool holder 12 and the tapered portion 14 is filled with the tapered portion 14, the supporting rigidity of the tool 10 in the radial direction is maintained, and the machining accuracy can be maintained. Similarly, as shown in FIG. 8, the contact portion between the tool holder 12 and the tapered portion 14 may be formed in a linear shape. In this case, the rotation of the main shaft body 30 causes the tapered portion 14 to expand in the radial direction by the centrifugal force, and the contact area of the contact portion decreases. However, since the position of the contact portion between the tool holder 12 and the taper portion 14 moves to the tool side, the tool holder 12 is gripped near the tool side. Therefore, rattling of the tool holder 12 is prevented, and the support rigidity in the radial direction of the tool holder 12 can be maintained substantially constant.

(2) Instead of the means for axially displacing the tapered portion 14 (compensation means) by the elastic force described in the first embodiment, a centrifugal force displacement means for displacing the compensation means by centrifugal force is applied. Good. This centrifugal force displacement means is, for example, in a spindle device 110 shown in FIG. 9, in which a plurality of grooves 106c extending in the axial direction are provided on the inner peripheral surface of a tapered concave portion 106a of a spindle body 106, and the grooves 106c are provided. A key 106b is provided so that it can slide. The depth of the groove 106b is set so as to decrease toward the tool side, and the key 106b protrudes into the recess 106a as the key 106b moves toward the tool side. according to this,
When the main shaft body 106 rotates at high speed and the recess 106a spreads outward, the key 106b moves to the tool side by centrifugal force, and the outer periphery of the tool holder 102 is constrained.
In this way, the key 106b fills the clearance created between the recess 106a and the tool holder 102.

(3) Similarly, inertial force displacement means for displacing the compensation means by inertial force may be applied. This inertial force displacing means is realized, for example, in the spindle device 110 shown in FIG. 10, by providing the movable member 104b movable along the circumferential direction of the tool holder 102 on the outer peripheral portion thereof. A ball, a key, or the like is used for the movable member 104b, and the movable member 104b is inserted into a groove along the circumferential direction of the tool holder 102. The depth of the groove is deep in the rotational direction and shallow in the counter rotational direction. For this reason, the movable member 104b moves to the shallower side of the groove due to the inertial force caused by the rotation of the main shaft body 106, and moves to a position where it projects outward so as to strongly press the outer peripheral portion of the tool holder 102. In this way, the movable member 104b moved by the inertial force fills the clearance that is likely to occur between the taper portion of the main spindle body 106 and the tool holder 102. Therefore, the tool holder 10
Since 2 is maintained at a fixed position in the radial direction, the supporting rigidity of the tool holder 102 in the radial direction can be maintained. In the case of the second embodiment, the inertial force displacing means may be applied to the tapered portion 68a.

(4) Instead of the means for deforming the tapered portion 68a (complementing means) by heat described in the second embodiment, a centrifugal force deforming means for deforming the compensating means by centrifugal force may be applied. In this centrifugal force deforming means, for example, in the main shaft 110 shown in FIG. 11, a plurality of cuts are made in the outer peripheral portion of the tool holder 102 along the axial direction, and the end pieces 104c formed by the cuts are subjected to centrifugal force. It is realized by configuring to spread. By doing so, the end piece 104c spreads by the centrifugal force, so that the end piece 104c fills the clearance that tends to occur between the taper portion of the spindle body 106 and the tool holder 102. In this way, since the tool holder 102 is maintained at a fixed position in the radial direction, the supporting rigidity of the tool holder 102 in the radial direction can be maintained.

(5) Countersunk springs 24, 28, 34, 64
Other elastic bodies such as a spiral spiral spring, a flat spiral spring, rubber, etc. can be optionally used depending on the size and weight of the spindle devices 22, 68. In this way, an appropriate elastic force is obtained, so that the drawbar 26 and the like can be appropriately pressed.

[0037]

[Other Aspects of the Invention] The embodiments of the present invention have been described above. Still other aspects of the invention will be listed below, and related explanations will be given if necessary.

[Mode 1] In the spindle device according to claim 1, the compensation means is provided at one of the tip end portion of the spindle body or the tool holder and is movable relative to the other. And spindle device. [Related Explanation of Aspect 1] The compensating means moves relative to the tip of the other spindle body or the tool holder to fill the clearance. Therefore, the processing accuracy can be maintained.

[Mode 2] One of the tool holder and the main spindle body is provided with a tapered concave portion, and the other is provided with a convex portion to be fitted into the concave portion. By inserting the convex portion, the main spindle body is inserted. In a main spindle device in which a tool holder is attached to the main shaft main body, a centrifugal force caused by high-speed rotation of the main spindle main body causes a peripheral edge of the concave portion to expand outward relative to the convex portion, and the opening edge of the concave portion is expanded. A spindle device, wherein a supplementary means for maintaining contact between the vicinity and the convex portion is added. [Related Explanation of Aspect 2] Since the contact between the vicinity of the opening edge of the concave portion and the convex portion is maintained by the filling means, the clamping force is maintained. In this way, since the supporting rigidity of the tool holder in the radial direction is maintained, the processing accuracy can be maintained.

[Aspect 3] A spindle device according to Aspect 2, wherein a fixing member for fixing the position of the tool holder is added. [Related Explanation of Aspect 3] Since the tool holder is further prohibited from moving in the axial direction by the fixing member, it is possible to more reliably maintain machining accuracy.

[0041]

According to the present invention, a tapered recess provided in one of the tool holder and the main spindle body,
The compensating means fills the clearance that is about to be generated by the rotation of the main shaft main body with the convex portion provided on the other side and fitted into the concave portion. In this way, since the supporting rigidity of the tool holder in the radial direction is maintained, the processing accuracy can be maintained.

[Brief description of drawings]

FIG. 1 is a diagram showing a spindle device provided with a tapered portion that is movable along an axial direction.

FIG. 2 is a diagram showing an operation of a taper portion.

FIG. 3 is a diagram showing a case where a clamper is fixed.

FIG. 4 is a diagram showing a spindle device provided with a heater.

FIG. 5 is a diagram showing a contact surface pressure between a tool holder and a spindle.

6 is a diagram showing an example in which a heat transfer member is provided in place of the heater of the spindle device shown in FIG.

7 is a diagram showing an example in which a power feeding mechanism is provided in the spindle device shown in FIG.

FIG. 8 is a diagram showing another example of the tapered portion shown in FIG.

FIG. 9 is a schematic view showing an example in which a means for displacing the filling member by centrifugal force is provided.

FIG. 10 is a schematic view showing an example in which a means for displacing the filling member by inertial force is provided.

FIG. 11 is a schematic view showing an example in which a means for deforming the filling member by centrifugal force is provided.

FIG. 12 is a diagram showing a spindle device in an unclamped state.

FIG. 13 is a diagram showing a spindle device in a clamped state.

FIG. 14 is a diagram showing the configuration of another tapered portion.

FIG. 15 is a diagram showing a configuration of unclamping means.

FIG. 16 is a diagram showing a configuration of another unclamping means.

FIG. 17 is a view showing a conventional spindle device.

[Explanation of symbols]

 10,50 Tool 12,52 Tool holder 14 Tapered part 16,54 Bearing 18,56 Spindle head 20,58 Built-in motor 22,60 Spindle device 24,28,34,64 Flat spring (elastic body) 26,66 Drawbar 30, 68 main shaft body 32 push bar 36 O-ring 38 cylinder 40 piston 62 heater (heat source) 70 coil 72 permanent magnet

Claims (4)

[Claims] 1. A tapered recess is provided in one of the tool holder and the main spindle body, and a convex portion that is fitted into the concave portion is provided in the other, and the main shaft is formed by inserting the convex portion into the concave portion. In the spindle device in which the tool holder is attached to the main body, when the vicinity of the opening edge of the concave portion spreads outward relatively to the convex portion due to the high-speed rotation of the main spindle body, the vicinity of the opening edge of the concave portion A spindle device, characterized in that a supplementary means for filling a clearance generated between the convex portion and the convex portion is added. 2. The spindle device according to claim 1, wherein the compensation means is provided on the convex portion and is a member that is deformed by heat or centrifugal force to fill the clearance. . 3. The spindle device according to claim 1, wherein the compensation means is a member that is displaced by any one of elastic force, centrifugal force, and inertial force to fill the clearance. apparatus. 4. The spindle device according to claim 1, 2, or 3, wherein a restraint member that restrains relative movement of the tool holder and the spindle main body in the axial direction is provided between the tool holder and the spindle main body. Characteristic spindle device.