JPH11138305A - Spindle device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the generation of a chatter by damping a self-exciting oscillation. SOLUTION: A preload member 9 is furnished with the first and the second laminate springs 91 and 92 held between the first spring seat 81 to be the end face of a rear lid 41b, and the second spring seat 82 to be the inner surface of a flange 42a provided at an inner tube member 42. Both laminate springs 91 and 92 are circular bodies laminating a pair of disk springs of the same form by uniforming their project sides, and they are contacted each other at the inner diameter side, and contacted to both spring seats 81 and 82 at the outer diameter side. The preload member energizes the both members 41 and 42 in the reverse directions along an axis RA. Consequently, almost a constant load seperating along the axis RA can be given between bearings 6 fixed to the inner tube member 42, and the self-exciting oscillation of a rotary member 2 can be prevented by a surface contact generated by laminating the disk springs.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spindle device used for cutting and grinding, and more particularly to a spindle device having a constant-pressure preload structure for applying a preload to a bearing.

[0002]

2. Description of the Related Art As a conventional spindle device, a constant-pressure preload structure for applying a constant preload in the axial direction between a pair of bearings movable in the axial direction and absorbing thermal expansion of a rotating shaft supported by the pair of bearings. Spindle devices are known.

FIG. 4 is a sectional view showing the structure of a conventional spindle device. This spindle device includes a rotating member 2
And a cylindrical stationary member 4 enclosing the rotating member 2.
The rotor 20 is fixed to the outer peripheral surface of the rotating member 2, and the stator 40 is fixed to the inner peripheral surface of the stationary member 4. The stationary member 4 supports the rotating member 2 rotatably about the axis RA via a pair of bearings 5 and 6. The stationary member 4 includes an outer cylinder member 41 that holds one bearing 5 inside, and an inner cylinder member 42 that fixes the other bearing 6 inside. Both members 4
The members 1 and 42 can move in the direction of the axis RA via the sliding surface 44, and the distance between the bearings 5 and 6 changes according to the change in the position of the members 41 and 42. In addition, the outer cylinder member 4
A spring hole 4 for accommodating the coil spring 45 is provided at one end.
1 a is formed, and one end of the coil spring 45 housed in the spring hole 41 a is in contact with a flange portion 42 a provided on the inner cylinder member 42. By the coil spring 45, the outer cylinder member 41 and the inner cylinder member 42 are relatively urged in opposite directions along the axis RA. As a result, the difference in thermal expansion between the rotating member 2 and the stationary member 4 is absorbed, and the two bearings 5,
6, a substantially constant load along the direction of the axis RA can be applied. In this spindle device, the spring constant of the coil spring 45 is considerably smaller than the spring constant of the bearings 5 and 6 (about 1/1000), so that the change in the bearing preload caused by elongation of the rotating member 2 and the like can be reduced. Preventing.

A spindle device disclosed in Japanese Utility Model Publication No. 6-15484 discloses a spindle device which applies a preload to a pair of bearings and absorbs thermal expansion of a rotary shaft. In this spindle device, a pair of opposed disc springs is used as a means for applying the above preload.

[0005]

However, in the former spindle device shown in FIG. 4, when the load applied to the rotating member 2 is alternately pushed and pulled in the direction of the axis RA during cutting, grinding, or the like, the rotating member is not rotated. 2 may self-excitedly vibrate in the direction of the axis RA to cause resonance called chatter.

Also, in the latter spindle device disclosed in Japanese Utility Model Publication No. 6-15484, when the load applied to the rotating member alternately changes in the axial direction by pushing and pulling, the rotating portion and the like move in the axial direction similarly to the above. Self-excited vibration may cause chatter.

Accordingly, an object of the present invention is to provide a spindle device capable of suppressing the occurrence of self-excited vibration in various use states.

[0008]

In order to solve the above-mentioned problems, a spindle device according to the present invention supports a first member and the first member so as to be rotatable together, and relatively rotates in the axial direction with each other. A spindle device having a preload structure, comprising: a slidable second and third member; and a preload member that generates a preload that axially urges the second member against the third member. The member is a laminated spring that is sandwiched between the second member and the third member, and is a laminated spring in which a plurality of plate-shaped springs are laminated so as to make surface contact.

In a preferred aspect, the laminated spring is a plurality of coned disc springs stacked in the same convex direction.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a spindle device according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a longitudinal sectional view showing the structure of the spindle device of the embodiment. This spindle device includes a rotating member 2 that is a spindle shaft and a cylindrical stationary member 4 that rotatably supports the rotating member 2.

The stationary member 4 includes an outer cylindrical member 41 for fixing a set of bearings 5 therein, and an inner cylindrical member 42 as a bearing sleeve for fixing a set of bearings 6 therein. Inner tube member 4
Numeral 2 is prevented from rotating around the axis RA by a detent mechanism (not shown), and is movable in the direction of the axis RA. The two members 41 and 42 are arranged concentrically around the axis RA and are relatively movable in the direction of the axis RA. In this way, by making the relative positions of the two members 41 and 42 variable, even when the rotating member 2 extends in the direction of the axis RA due to thermal expansion, the interval between the two bearings 5 and 6 is changed by the amount of the extension. Thus, it is possible to prevent unnecessary distortion loads from being generated in the dual bearings 5 and 6.

A mechanism for making the relative positions of the two members 41 and 42 variable will be described in more detail. The inner circumference of the rear lid 41b fixed to one end of the main body 41a of the outer cylinder member 41 faces the outer circumference of the inner cylinder member 42 with a plurality of balls 7 interposed therebetween. In other words, the inner circumference of the rear lid 41b and the outer circumference of the inner cylinder member 42 are kept at the same distance, and the rear lid 41b and the inner cylinder member 42 move smoothly in the direction of the axis RA and move relative to each other in the direction of the axis RA. Is changing. Note that the rear cover 41
The ball 7 arranged in the gap between the inner cylinder member 42 and the inner cylinder member 42 is guided by a holder (not shown).

The preload member 9 and the two members 41 and 42 are urged in opposite directions along the axis RA. Thereby, the outer cylinder member 41
The bearing 5 fixed to the inner cylinder member 42 and the bearing 6 fixed to the inner cylinder member 42 can apply a substantially constant load that is separated in the direction of the axis RA.

The preload member 9 is provided on the outer periphery of the inner cylinder member 42 with a first spring seat 81 which is a rear end face of the rear lid 41b and an inner cylinder member 42
Spring seat 8, which is the front end face of flange portion 42a provided at
2, a first and a second laminated spring 91 sandwiched between
92. Each of the laminated springs 91 and 92 is an annular body formed by laminating a pair of disc springs of the same shape with their convex directions aligned, and is in contact with each other so as to face each other on the inner diameter side. 81 and 82 are in contact.

The rotor 20 is fixed on the outer peripheral surface of the rotating member 2, and the rotor 2 is fixed on the inner peripheral surface of the main body 41 a of the outer cylindrical member 41.
The stator 40 is fixed so as to face 0. The rotor 20 and the stator 40 constitute a motor. In addition, an induction coil 40 a is wound around the stator 40. By supplying power to the coil 40a at an appropriate timing, the rotating member 2 rotates with respect to the stationary member 4. A processing tool, for example, can be connected to the extension of the rotating member 2, and in this case, processing such as cutting and grinding becomes possible.

FIGS. 2 and 3 are views for explaining the structure of the laminated spring 92. FIG. FIG. 2 is a view for explaining the structure of one disc spring 92a constituting the laminated spring 92 of FIG. 1. FIG. 2 (a) is a plan view, and FIG. 2 (b) is a side sectional view. is there. The disc spring 92a is an annular plate-like body having one convex side, and has a convex outer surface US and a concave inner surface IS.
And

FIG. 3 is a side sectional view of the laminated spring 92. The laminated spring 92 in FIG. 1 is configured by laminating a pair of disc springs 92a and 92b having the structure shown in FIG. 2 as shown in FIG. 3, and includes an inner surface IS of the disc spring 92a and an outer surface US of the disc spring 92b. Are in surface contact. Thus, both disc springs 9
2a and 92b are brought into surface contact with each other and
Can be prevented from causing the resonance called chatter due to the self-excited vibration of the rotating member 2 in the direction of the axis RA. That is, both laminated springs 91, 92 are sandwiched between the spring seats 81, 82.
Is compressed, for example, the second laminated spring 92 deforms flat. Thus, in the second laminated spring 92, a frictional force is generated due to surface contact between the pair of disc springs 92a and 92b. This frictional force damps self-excited vibration when a forward / reverse load is applied to the rotating member 2 in the direction of the axis RA, thereby effectively suppressing chatter. Note that a pair of disc springs 92a, 9
If the outer diameters are not overlapped with each other and the outer diameters are in contact with each other, no frictional force is generated between the pair of disc springs 92a and 92b. Would.

Further, by forming the laminated spring 92 by laminating the disc springs 92a and 92b, the spring constant in the direction of the axis RA can be increased as compared with a coil spring or the like, and the amount of compressive deformation thereof is relatively small. Thus, the effect of preventing the occurrence of self-excited vibration can be enhanced. The spring constant of the preloading member 9 including the pair of laminated springs 91 and 92 is
6 is adjusted so as to fall within a range of about 1/20 to 1/70 of the spring constant of itself. That is, the material and shape of the coned disc spring constituting the preload member 9 and the spring seat 8 for sandwiching them
The spring constant of the preloading member 9 is appropriately set by appropriately adjusting the intervals and the like of 1, 82.

Although the present invention has been described with reference to the embodiment, the present invention is not limited to the above embodiment. For example, the preload member 9 sandwiched between the pair of spring seats 81 and 82 may be constituted by only a single laminated spring 91, and may be a combination of three or more laminated springs. You may.

Further, the laminated springs 91 and 92 are not limited to a laminate of two disc springs, but may be a laminate of three or more disc springs with their convex directions aligned.

The laminated springs 91 and 92 are connected to the inner cylindrical member 4.
It is not necessary to arrange concentrically with 2;
A plurality of small laminated springs having a diameter substantially equal to the radial width of the two spring seats 81 and 82 may be prepared, and these may be arranged at appropriate intervals.

Further, the laminated springs 91 and 92 are not limited to laminated disc springs, but may be composed of laminated various plate-shaped springs.

The mechanism for making the relative positions of the two members 41 and 42 variable is not limited to the ball bush type sliding mechanism shown in FIG. Can be.

[0025]

As is apparent from the above description, according to the spindle device of the present invention, the preload member is provided with the second preload member.
Since it is a laminated spring that is sandwiched between a member and the third member and is laminated so that a plurality of plate-shaped springs are brought into surface contact, the relative position of the second and third members changes. When each spring is deformed, a frictional force is generated due to surface contact between the springs. This frictional force attenuates the self-excited vibration,
The self-excited vibration when a forward / reverse load in the axial direction is applied to the member is attenuated to suppress chatter.

In a preferred embodiment, since the laminated spring is a plurality of disc springs stacked in the same convex direction, the self-excited vibration can be effectively prevented with a simple structure.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view illustrating the structure of a spindle device according to an embodiment of the present invention.

FIGS. 2 (a) and 2 (b) are a front view and a side sectional view showing a structure of a disc spring constituting a main part of the spindle device of FIG. 1;

FIG. 3 is a diagram illustrating a structure of a laminated body in which the disc springs of FIG. 2 are laminated.

FIG. 4 is a longitudinal sectional view illustrating the structure of a conventional spindle device.

[Explanation of symbols]

 Reference Signs List 2 rotating member 4 stationary member 5, 6 bearing 9 preload member 41 outer cylinder member 41a main body 41b back lid 42 inner cylinder member 42a flange portion 81, 82 spring seat 91, 92 first and second laminated springs 92a, 92b coned spring RA axis

Claims (1)

[Claims] 1. A first member, a second member and a third member which rotatably support the first member together and are slidable relative to each other in the axial direction, and the second member A preload structure spindle device comprising: a preload member that generates a preload that urges a third member in an axial direction, wherein the preload member is sandwiched between the second member and the third member. And a stacked spring in which a plurality of plate-shaped springs are stacked so as to make surface contact.