JPH10263902A - Spindle device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a spindle device having support rigidity so high as to hold tools even when a large force applies to axial direction in processing. SOLUTION: A tool holder 103 is attached to a spindle shaft 101, and a setscrew 152 which prevents the approach of a flange unit 103b of the tool holder 103 and the spindle shaft 101, is provided. Accordingly, even when a comparatively large force is loaded in an axial direction, the contact state between a taper shunk unit 104 of the tool holder 103 and a sleeve for fixing 133 is maintained, which enables sufficient holding of the tool holder 103.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a spindle device used for a machine tool or the like.

[0002]

2. Description of the Related Art For example, a lathe or a machining center (M
In a machine tool such as C), a spindle device as disclosed in JP-A-7-178607 is used for attaching a tool coaxially to a rotating shaft. FIG.
It is an axial sectional view of such a spindle device according to the prior art.

In FIG. 4, a spindle shaft 1 is rotatably supported horizontally in a housing 8 via a plurality of (four in the figure) ball bearings 6 and one roller bearing 7. The housing 8 has a cylindrical shape surrounding the outer periphery of the bearings 6 and 7 and has an outer cylinder 1 having a mounting flange 9 on the outer periphery.
0, a front lid 11 fixed to the left end face of the outer cylinder 10 with bolts B1 and a rear lid 12 fixed to the right end face with bolts B2.
It is composed of

[0004] When the spindle device of FIG. 4 is mounted on a bore (not shown) of a lathe or the like, E forms a spiral passage between the bore and the inner surface of the bore. The cooling fluid is circulated to cool the spindle device. The front lid 11 is provided with the outer race 6 of the plurality of ball bearings 6.
a is fixed to the inner surface of the housing 8 via the outer spacer. The inner ring 6b of the ball bearing 6 is fixed to the outer peripheral surface of the spindle shaft 1 by a retaining ring via an inner spacer.

On the other hand, the rear lid 12 is provided with an outer race 7a of the roller bearing 7
Is fixed to the inner surface of the housing 8. The inner ring 7 b of the roller bearing 7 is fixed to the outer peripheral surface of the spindle shaft 1 via a ring-shaped inner ring pressing cover 16 by a pulley 17 that is in contact with the inner ring pressing cover 16. The pulley 17 is attached to the outer peripheral surface of the spindle shaft 1 by interference fit. F is a fluid pressure supply port that applies pressure to the fitting surface when the pulley 17 is attached or detached.

At the center of the shaft end of the spindle shaft 1 rotatably supported in this way, a tapered hole 2 for mounting a tool is formed. Further, a through hole 18 that extends from the back of the tapered hole 2 to the rear end of the spindle shaft is provided with the spindle shaft 1.
Are formed through the axis of the shaft. A tool attachment / detachment mechanism described below is disposed in the through hole 18.

A tapered shank 4 of a tool holder 3 for holding a tool 21 is fitted into the tapered hole 2. The tool holder 3 is provided with a flange portion 3f having a larger diameter than the taper shank portion 4 on the left side of the taper shank portion 4. A pull stud 22 having a small-diameter neck portion 22a and a large-diameter head portion 22b is provided on the right side of the tapered shank portion 4 so as to extend into the through hole 18 of the spindle shaft. ing.

The tool attaching / detaching mechanism arranges a plurality of balls 23 for holding the pull studs 22 of the tool holder 3 extending into the through hole 18 at equal intervals in the circumferential direction and holds the balls 23 so as to be retractable in the radial direction. A drive draw bar 25 for driving the sleeve 24 to move forward and backward passes through the through hole 18, and the right end thereof protrudes from the spindle shaft 1.

The right end of the drawbar 25 is driven to be pressed by a piston (not shown). When the push of the drawbar 25 is released by the piston, the drawbar 25 is retracted by a disc spring 26, and Thereby, the sleeve 24 is also retracted.

At this time, the ball 23 moves from the relatively large-diameter space 18a of the through hole 18 to the smaller-diameter space 18b.
While being pushed by the inner peripheral surface of the hole, protruding toward the inner diameter side of the sleeve 24, and locked to the neck 22 b of the pull stud 22 in the tool holder 3. Also, the piston 2 is driven to
When the ball 4 is moved forward, the ball 23 moves into the large-diameter space 18a of the through hole 18, and can be retracted by the expansion of the inner diameter, so that the ball 23 is retracted from the inner diameter surface of the sleeve 24.
Thereby, the tool holder 3 can be extracted.

A number of disc springs 26 are mounted on the outer periphery of the draw bar 25 inside the through hole 18, and constantly urge the draw bar 25 rightward. 27 is a disc spring 26
, A fixing nut 28 for fixing the pressing ring 27 to the spindle shaft 1, and 29 a tool holder 3
And a drive key for positioning the spindle shaft 1 in the rotation direction, and is fixedly attached to the spindle shaft 1a with bolts B3.

On the outer periphery of the spindle shaft 1, a fixing sleeve 33 having a predetermined interference with the spindle shaft 1 is fitted. Connected to the source. Note that the interference of the fixing sleeve 33 is a tight fit to the extent that the fixing sleeve 33 fitted to the end of the spindle shaft 1 is firmly tightened and held.

The spindle device constructed as described above is mounted on a spindle mount of a machine tool via a flange 9 of a housing 8. A pulley 17 at the right end of the spindle shaft 1 is connected to an output shaft of a drive motor (not shown) via a belt and is driven to rotate.

When the tool holder 3 is mounted on the shaft end of the spindle shaft 1, the draw bar 25 of the tool attaching / detaching mechanism is advanced by driving a piston (not shown) against the elasticity of the disc spring 26. In this state, the tapered shank portion 4 of the tool holder 3 is inserted into the tapered hole 2 of the spindle shaft 1.

When the flange portion of the tool holder 3 comes to a position close to the fixing sleeve 33, the hydraulic pressure P is supplied through the port 35. Due to the hydraulic pressure, a radially outward force acts on the inner peripheral surface of the fixing sleeve 33,
The inner diameter of the fixing sleeve 33 is expanded, and the interference of the fixing sleeve 33 with respect to the spindle shaft 1 is canceled.

At the same time, a force in the thrust direction acts between the spindle shaft 1 and the fixing sleeve 33, whereby the distal end surface of the fixing sleeve 33 comes into contact with the flange 3f of the tool holder 3. In this state, the tool holder 3
, The taper shank portion 4 of the tool holder 3 is fitted into the taper hole 2, and the pull stud 22 at the top of the taper shank portion 4 is fitted into the sleeve 24 at the tip of the tool attaching / detaching mechanism.

In such a case, when the drive of the piston (not shown) is released, the drawbar 25 is retracted, and the sleeve 24 is moved from the large-diameter space 18a of the through hole 18 to the small-diameter space 1.
8b, the ball 23 of the sleeve is pushed by the space 18b to a small diameter and protrudes inside the sleeve 24, and the root of the head 22b of the pull stud 22 of the tool holder 3 is pulled in, thereby holding the tool holder 3. It will be.

The drawbar 25 is urged rightward by the strong elastic force of the large number of disc springs 26 so that the tapered surface of the tapered shank portion 4 of the tool holder 3 comes into close contact with the inner surface of the tapered hole 2. It has become.

Thereafter, by removing the hydraulic pressure applied to the inner surface of the fixing sleeve 33, the inner diameter of the fixing sleeve 33 is reduced, and the outer periphery of the spindle shaft 1 is tightened.
At this time, the distal end surface of the fixing sleeve 33 is kept in close contact with the end surface of the flange portion 3f of the tool holder 3, but there is a predetermined clearance between the end surface of the flange portion 3f and the distal end surface of the spindle 1. Is interposed. Therefore, when attaching or detaching the mounted tool holder 3 from the spindle shaft 1, there is no need to apply hydraulic pressure, and the taper hole 2 and the taper shank portion 4 are simply moved forward by simply driving the drawbar 25 of the tool attachment / detachment mechanism forward. It is sufficient to release the fitting of the pull stud 22 and the grip of the pull stud 22 by the ball 23.

[0020]

In such a spindle device according to the prior art, the distal end surface of the fixing sleeve 33 is in close contact with the end surface of the flange portion 3f of the tool holder 3, so that the tool holder 3 is provided with high rigidity. It is possible to hold, and it is possible to perform cutting work and the like that is stable against axial force.
However, since the fixing sleeve 33 is held on the spindle 1 only by the frictional force based on the interference,
For example, in heavy cutting in which a force greater than the frictional force based on the interference is applied to the tool in the axial direction, the degree of contact between the tapered hole and the tapered shank may not always be correct on the entire surface. As a result, there is a possibility that cutting may become unstable due to misalignment or wobble of the tool.

The present invention has been made in view of the above problems, and has as its object to provide a spindle device having a high supporting rigidity enough to hold a tool even when a large axial force is applied during machining.

[0022]

In order to achieve the above-mentioned object, a spindle device according to the present invention has a spindle shaft having a tapered hole for mounting a tool formed at an end thereof, and is fitted into the tapered hole of the spindle shaft. A tool holder having a tapered shank portion to be formed and a flange portion having a larger diameter than the tapered shank portion, and a fixing sleeve fitted to the outer periphery of the spindle shaft and having one end abutting on the flange portion. And prevention means for preventing the flange portion of the tool holder from approaching the spindle shaft when the tool holder is attached to the spindle shaft.

[0023]

According to the spindle device of the present invention, when the tool holder is attached to the spindle shaft, there is provided a prevention means for preventing the flange portion of the tool holder from approaching the spindle shaft. Because
Even when a relatively large force is applied in the axial direction, the abutting state between the tapered shank portion of the tool holder and the fixing sleeve is maintained, so that the tool holder can be sufficiently held. Become.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a spindle device according to an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is an axial sectional view showing a part of a spindle device according to a first embodiment of the present invention. The detailed description of the configuration common to that of the related art in FIG. 4 is omitted.

In FIG. 1, a spindle shaft 101 having a tapered hole 102 formed coaxially at one end has a small diameter portion 130 and a large diameter portion 131 formed on the outer periphery thereof. The fixing sleeve 133 is arranged so that the inner circumference faces the outer circumference of the spindle shaft 101. Fixing sleeve 133
Are the small diameter portion 130 and the large diameter portion 131 of the spindle shaft 101.
And a small diameter portion 133b and a large diameter portion 133c each having an inner diameter corresponding to. The fixing sleeve 133
The inner diameters of the small diameter portion 133b and the large diameter portion 133c are smaller than the outer diameters of the small diameter portion 130 and the large diameter portion 131 of the spindle shaft 101 by a predetermined amount. Therefore, the fixing sleeve 133 is attached to the outer periphery of the spindle shaft 101 by shrink fitting. Further, a flange 133g extending inward in the radial direction is formed at the left end of the fixing sleeve 133.

In the spindle shaft 101, the small diameter portion 13
0 and the large diameter portion 131 are formed by a step 132 extending in the radial direction.
Connected by On the other hand, also in the fixing sleeve 133, the small diameter portion 133b and the large diameter portion 133c are connected by a step 133d extending in the radial direction. Further, the fixing sleeve 133 includes two steps 133d, 132d.
A port 135 is provided at the upper portion of the port 135, which communicates with the outside from the outside in a ring-shaped closed space partially sandwiching the portion. Port 135 has
For example, a pipe (not shown) for supplying a hydraulic pressure from a hydraulic source (not shown) such as a hydraulic pump or the like is connected. The area of the step portion 133d is determined from the relationship with the supplied oil pressure so that a necessary axial moving force of the fixing sleeve 133 can be obtained. When the tool holder is mounted, a predetermined clearance Δ is provided between the flange 133g of the fixing sleeve 133 and the end surface 101b of the spindle shaft 101.
(In this embodiment, 0.5 mm or more is sufficient)
It is necessary to provide an adjustment allowance for the set screw described later.

A male screw 101a is engraved on the right side of the fixing sleeve 133 and on the outer periphery of the spindle shaft 101, and a female bearing 150a is screwed into the male screw 101a. Installed. The right end of the bearing holding nut 150 contacts the inner ring 106b of the ball bearing 106 that rotatably supports the spindle shaft 101 with respect to the housing 108, and the ball bearing 1
06 is fixed. Since the outer ring 106a of the ball bearing 106 is fixed to the housing 108, the bearing holding nut 150 does not move rightward from the illustrated state even when a large force is applied.

On the outer periphery of the bearing holding nut 150, a full-circumferential projection 150b projecting rightward is formed.
An annular front lid 111 attached to an end of the housing 108 radially outward of the bearing holding nut 150.
Is formed on the inner circumference with a full circumference projection 111a protruding leftward. The circumferential protrusions 150b and 111a have complementary shapes at a predetermined distance from each other, and form a clearance of a labyrinth structure therebetween to prevent foreign matter from entering while maintaining a non-contact relationship. To work. Note that a seal 151 for preventing intrusion of a large foreign substance is attached to the left side of the front lid 111.

In this embodiment, a hole 133e extending in the axial direction is formed below the fixing sleeve 133, and a female screw 133f is formed near the right end of the hole 133e. The male screw 152a formed on the outer periphery is screwed into the female screw 133f so that the set screw 15
2 are arranged in the hole 133e. The right end of the set screw 152 faces the left end surface of the bearing holding nut 150, while the left end of the set screw 152 has a hexagonal hole 152b.
Are formed.

The tool holder 103 includes a holder tip 121
(Partially omitted), the flange portion 103b, the tapered shank portion 104, and the pull stud 122 are integrally formed coaxially in this order. The outer diameter of the flange portion 103b is larger than the inner diameter of the flange 133g of the fixing sleeve 133, so that the right end 103a of the flange portion 103b abuts the left end 133a of the fixing sleeve 133 when the tool holder 103 is mounted. Has become.

The pull stud 122 includes a relatively long small diameter portion 122b and a head portion 122a formed at the tip thereof. A plurality of balls 123 are arranged on the outer periphery of the small diameter portion 122b and adjacent to the head 122a. Ball 1
Reference numeral 23 is included in a sleeve 124 provided in a through hole 118 penetrating the spindle shaft 101 in the axial direction. The through-hole 118 is provided between the tapered hole 102 and the enlarged diameter portion 1.
18a.

Next, the operation of this embodiment will be described below. The set screw 152 is assumed to be retracted into the hole 133e. When attaching the tool holder 103 to the shaft end of the spindle shaft 101, the sleeve 124 of the tool attaching / detaching mechanism is advanced leftward by driving a piston (not shown). In this state, the tapered shank portion 104 of the tool holder 103 is
02.

When the flange portion of the tool holder 103 comes to a position close to the fixing sleeve 133, the port 13
5 is supplied with hydraulic pressure. Due to the hydraulic pressure, a radially outward force acts on the inner peripheral surface of the fixing sleeve 133, the inner diameter of the fixing sleeve 133 is expanded, and the tightening force of the fixing sleeve 133 on the spindle shaft 101 is released. You.

At the same time, an axial force acts between the spindle shaft 101 and the fixing sleeve 133, whereby the end surface 133 a of the fixing sleeve 133 comes into close contact with the end surface 103 a of the flange portion 103 b of the tool holder 103. Touch

In this state, the tool holder 103 is further pressed against the spindle shaft 101, the taper shank portion 104 of the tool holder 103 is fitted into the taper hole 102, and the pull stud 122 at the top of the taper shank portion 104 is inserted into the tool. It fits into the sleeve 124 at the tip of the attachment / detachment mechanism.

In such a case, when the drive of the piston (not shown) is released, the sleeve 124 moves from the large-diameter portion 118a toward the smaller-diameter through hole 118, and the ball 123 in the sleeve is pushed into the through hole 118. Being sleeve 1
24, the tool holder 103 is held by applying a pressing force to the head 122b of the pull stud 122 of the tool holder 103 and pulling it in. The axial movement force of the fixing sleeve 133 is set to be smaller than the pull-in force of the tool holder 103 by the sleeve 124.

The sleeve 124 is urged rightward by a strong elastic force of a disc spring (not shown) so that the tapered surface of the tapered shank portion 104 of the tool holder 103 comes into close contact with the inner surface of the tapered hole 102. It has become.

Thereafter, the oil pressure applied to the inner surface of the fixing sleeve 133 is reduced to thereby reduce the pressure of the fixing sleeve 133.
Is reduced, whereby the outer periphery of the spindle shaft 101 is tightened. In this state, a tightening tool (not shown) is screwed into the hexagonal hole 15 of the set screw 152 through the hole 133e.
2b, and the set screw 1
The projection 52 is made to project, and its tip is brought into contact with the left end face of the bearing holding nut 150.

At this time, the end surface 133a of the fixing sleeve 133 is kept in close contact with the end surface of the flange portion 103b of the tool holder 103, but the end surface of the flange 133g of the fixing sleeve 133 and the end surface of the spindle shaft 101 are , There is a predetermined clearance Δ. Therefore,
The mounted tool holder 103 is moved to the spindle shaft 101.
It is not necessary to apply a hydraulic pressure when attaching and detaching from the ball, and by simply driving the sleeve 124 forward, the fitting between the tapered hole 102 and the tapered shank portion 104 and the ball 1
It is sufficient to release the grip of the pull stud 122 by 23.

According to the present embodiment, the tip of the set screw 152 is brought into contact with the left end face of the bearing holding nut 150 in a state where the tool holder 103 is mounted. Even when a large force is applied to the right side, the fixing sleeve 133 is prevented from moving to the right side, so that the holding of the tool holder 103 is ensured, so that heavy cutting or the like can be performed. ing.

The protrusion amount δ of the set screw 152 can be changed according to the dimensional relationship among the spindle shaft 101, the tool holder 103, and the fixing sleeve 133 by adjusting the screwing angle.

Next, a spindle device according to a second embodiment of the present invention will be described, focusing on only the differences from the first embodiment shown in FIG. Second
This embodiment is different from the first embodiment in the configuration of the set screw. FIG. 2 is a partial cross-sectional view of the fixing sleeve 233 according to the second embodiment.

In FIG. 2, a hole 233e extending in the axial direction is formed below the fixing sleeve 233, and a female screw 233f is formed in the right half of the hole 233e. On the other hand, the bolt 252 has a cylindrical shaft portion 252c, and forms a male screw 252a in the right half thereof. The bolt 252 is inserted into the hole 233e, and the male screw 252a is inserted.
Is screwed into the female screw 233f.

The right end of the bolt 252 faces the left end surface of the bearing holding nut 150, while its main body 252
A hexagonal hole 252b is formed at the left end of c. Since the overall length of the bolt 252 is slightly longer than the axial length of the hole 233e, the hexagon hole 252b of the bolt 252 is exposed from the hole 233e in the attached state.

The operation of the second embodiment will be described. After the tool holder is mounted on the spindle shaft in the same procedure as in the first embodiment described above, the inner diameter of the fixing sleeve 233 is reduced by reducing the hydraulic pressure applied to the inner surface of the fixing sleeve 233. Thus, the outer periphery of the spindle shaft is tightened. In this state, by inserting a tightening tool (not shown) into the hexagonal hole 252b of the bolt 252 and rotating the bolt, the bolt 252 is protruded and its tip is brought into contact with the left end face of the bearing holding nut 150.

According to the present embodiment, the tip of the bolt 252 is brought into contact with the left end face of the bearing holding nut 150 in a state where the tool holder is mounted, so that a large force is applied rightward in the axial direction from the tool. , The fixing sleeve 233 is prevented from moving to the right,
Thereby, the holding of the tool holder is ensured, so that heavy cutting or the like can be performed.

In addition, according to the present embodiment, the bolt 25
Since the second hexagonal hole 252b is located at a position within the hole 233e where a general tightening tool (for example, a hexagonal wrench) can sufficiently reach, the bolt 252 can be tightened using such a tightening tool, and the first embodiment Unlike special tools, special tools are not required for tightening.

The amount of protrusion of the bolt 252 can also be changed according to the dimensional relationship between the spindle shaft, the tool holder, and the fixing sleeve 233.

Next, a description will be given of a spindle device according to a third embodiment of the present invention, focusing on only different portions from the first embodiment shown in FIG. Third
This embodiment is different from the first and second embodiments in the manner of fixing the fixing sleeve. FIG.
FIG. 2 is a partial cross-sectional view of the spindle device according to the embodiment, similar to FIG. 1.

In the embodiment shown in FIG. 3, a male screw 301a engraved on the outer periphery of the spindle shaft 301 is extended leftward in the axial direction, and a nut 352 is attached to the male screw 301a.
Is screwed. The left end surface 352a of the nut 352 is
It faces the right end surface 333h of the fixing sleeve 333.

The operation of the third embodiment will be described. After the tool holder is attached to the spindle shaft in the same procedure as in the first embodiment described above, the inner diameter of the fixing sleeve 333 is reduced by reducing the hydraulic pressure applied to the inner surface of the fixing sleeve 333. Thus, the outer periphery of the spindle shaft 301 is tightened. In this state, the left end surface 352 a is rotated by a tightening tool (not shown) via the nut 352 to abut the right end surface 333 h of the fixing sleeve 333.

According to this embodiment, since the nut 352 is in contact with the fixing sleeve 333 in a state where the tool holder 103 is mounted, a large force is applied rightward in the axial direction from the tool. However, the fixing sleeve 333 is prevented from moving rightward, whereby the holding of the tool holder 103 is ensured, so that heavy cutting or the like can be performed.

In addition, according to the present embodiment, when the tool holder is attached, the nut 352 is not in contact with the bearing holding nut 150, so that a large force is transmitted rightward in the axial direction from the tool. However, this force is prevented from being transmitted to the bearing 106 via the bearing holding nut 150, so that the preload state of the bearing 106 is not changed by the force from the tool.

The axial position of the nut 352 can be changed according to the dimensional relationship between the spindle shaft 301, the tool holder 103, and the fixing sleeve 333. The set screw 152, the bolt 252, and the nut 352 constitute the prevention means.

As described above, the present invention has been described with reference to the embodiments. However, the present invention should not be construed as being limited to the above embodiments, and it is needless to say that the present invention can be appropriately changed and improved. is there. In the above-described embodiment, nuts and bolts are used to prevent the movement of the fixing sleeve. However, the present invention is not limited to this, and for example, an appropriate thickness is provided between the bearing holding nut and the fixing sleeve. You may chew a shim.

[0056]

According to the spindle device of the present invention, when the tool holder is mounted on the spindle shaft,
Since a preventing means for preventing the flange portion of the tool holder from approaching the spindle shaft is provided, even when a relatively large force is applied in the axial direction, the taper shank portion and the fixing sleeve of the tool holder are provided. Abutment between the tool holder and the tool holder is thereby provided.

[Brief description of the drawings]

FIG. 1 is an axial sectional view showing a part of a spindle device according to a first embodiment of the present invention.

FIG. 2 is an axial sectional view showing a part of a fixing sleeve according to a second embodiment of the present invention.

FIG. 3 is an axial sectional view showing a part of a spindle device according to a third embodiment of the present invention.

FIG. 4 is a cross-sectional view showing the entire spindle device according to the related art.

[Explanation of symbols]

 101, 301 ‥‥ spindle shaft 103 ‥‥ tool holder 133, 233, 333 ‥‥ fixing sleeve 152 ‥‥ set screw 252 ‥‥ bolt 352 ‥‥ nut

Claims (1)

[Claims] 1. A spindle shaft having a tapered hole for tool attachment formed at an end portion, a tapered shank portion fitted into the tapered hole of the spindle shaft, and a flange portion having a larger diameter than the tapered shank portion. A tool holder, a fixing sleeve fitted to the outer periphery of the spindle shaft, and one end of which is brought into contact with the flange portion; and the tool when the tool holder is attached to the spindle shaft. A spindle device comprising: a prevention unit for preventing the flange portion of the holder from approaching the spindle shaft.