JP2501874Y2 - Spindle device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to an improvement of a spindle device having a balance ring.

[Problems to be solved by conventional techniques and devices]

In the conventional spindle device, since the balance ring is fixed to the spindle shaft by shrink fit, once attached, it is almost impossible to remove it. For example, in the case of a motor built-in spindle for a machining center, because the shaft mounting parts such as the bearing and rotor inserted through the spindle shaft are removable, the mounting positional relationship with the balance ring is limited and the degree of freedom in design is low. Few. That is, the balance ring is arranged in the middle of the two bearings, that is, in front of and behind the rotor so as to be sandwiched at a predetermined distance from the rotor, and is attached by shrink fit.

This balance ring is fixed to the shaft and firmly attached so that it is not loosened by centrifugal force due to high speed rotation.
Therefore, the balance flange and the rotor could not be removed, which was the same as the case where the fixed flange was formed on the spindle shaft.

For this reason, the bearing must be able to be pulled out toward the front end and the rear end of the spindle shaft, respectively. Therefore, the shaft end of the spindle shaft has a structure that cannot be made larger than the inner diameter of the bearing.

However, the shaft diameter at the front end cannot be reduced because a taper hole for mounting a tool is provided at the front end of the spindle. Therefore, the entire shaft diameter and bearing must be large, and the rotor diameter also becomes large, so the moment of inertia becomes large, the rotation speed is limited, and high-precision rotation control becomes difficult. There were problems such as.

[Means for Solving the Problem] In the spindle device of the present invention, a front end of a rotatable spindle shaft supported in a housing by a bearing has a portion having a diameter larger than an inner diameter of the bearing, and At least one balance ring is removably attached to the shaft.

Any one of the following configurations is provided as a detachable attachment mechanism of the balance ring.

The balance ring is fitted to the outer diameter of the spindle shaft with a tightening margin, and a screw hole for connecting to a hydraulic supply hose is provided on the outer surface of the balance ring, and the screw hole opens on the inner surface of the balance ring. It is in communication with the pores.

The balance ring is screwed to the outer diameter of the spindle shaft with a tightening allowance, and is screwed to a sleeve having a screw hole connected to the hydraulic supply hose on the outer surface and a hole communicating with the screw hole and opening to the inner surface. .

The balance ring is fixed to the spindle shaft by a wedge member having an inner surface that slides on the outer surface of the spindle shaft.

The balance ring is fixed to the spindle shaft with a set screw screwed to the balance ring.

The balance ring is fixed to the spindle shaft with a nut screwed with a screw engraved on the spindle shaft.

The balance ring is composed of a plurality of divided pieces divided by a center line, and each divided piece is an annular body which is coupled with a screw and is fastened to the spindle shaft.

[Action]

The balance ring once fixed to the spindle shaft can now be easily removed. Therefore, the bearing can be easily replaced. Also, the bearing and other spindle mounting parts can be attached and detached only from one end side of the spindle. As a result, it is possible to realize a rotary spindle device which has a large degree of freedom in the layout of assembling parts to the spindle, and can reduce the spindle moment other than the front end of the spindle for mounting the tool to reduce the overall moment of inertia.

〔Example〕

 Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows an embodiment of the present invention. The outer diameter of the spindle shaft 1 is the largest at the front end (left end) portion, and is made thinner from the step portion 2 and thereafter, and a tool mounting taper hole is formed at the front end.

Two angular ball bearings 3 are provided with a front bearing housing 6 via an inner ring spacer 4 and an outer ring spacer 5 for applying a preload.
The front bearing block 7 fitted to the inner diameter surface of is inserted from the rear end of the spindle shaft 1, and one side surface of the inner ring 3A of the ball bearing 3 on the front side is locked to the step portion 2. One side surface of the outer ring 3B of the ball bearing 3 is locked to a front lid 8 attached to an end surface of the front bearing housing 6. Next, the fixed sleeve 10 which has been warmed and whose inner diameter has been expanded is inserted from the rear end of the spindle shaft 1. The tip of the fixed sleeve 10 is pushed until it comes into contact with the side surface of the inner ring 3A of the rear ball bearing 3 so as to push in the axial direction.
The fixed sleeve 10 is fixed to the outer diameter of the spindle shaft 1 at room temperature by fitting with a tight margin, that is, by shrink fitting. The inner diameter surface having the tightening allowance has a hydraulic chamber 11 as a detaching means for taking out the fixing sleeve 10 by applying an oil pressure at the time of detaching and expanding the inner diameter.

When hydraulic pressure is supplied from the hydraulic pressure supply port 12 which is a screw hole provided on the side surface of the fixed sleeve 10, since this screw hole communicates with the hydraulic chamber 11 on the inner surface of the sleeve by a fine hole, the hydraulic pressure is the inner surface of the fixed sleeve 10. And the fixed sleeve 10 is expanded in diameter, the oil communicates with the hydraulic chamber 11, and the fixed sleeve 10 moves to the right by hydraulic pressure and can be removed.

A first balance ring 13, which is inserted into the spindle shaft 1 by a loose fit, is integrally fixed to the rear end surface of the fixed sleeve 10 by using a hexagon socket head cap screw 14 as a detaching means. The fixed sleeve 10 and the first balance ring 13
Is aligned with the alignment mark engraved on the spindle shaft 1,
Always installed in the same phase.

Subsequently, the warmed and expanded inner diameter rotor 15 is likewise inserted from the rear end side of the spindle shaft 1 and fixed to the outer diameter of the spindle at a predetermined position somewhat away from the balance ring 13 by fitting with a tight margin. To be done. This fixed also the rotor
By aligning the alignment marks of 15 and the spindle shaft 1, it is always performed in the same phase. The rotor 15 has an aluminum die-cast rotor bar inserted into the laminated iron core.
It has a cage shape with both ends connected by a short-circuit ring 15a, and is generally unbalanced. Therefore, it is conceivable to give a hole for balance adjustment to this short-circuit ring 15a to achieve balance, but since the material is aluminum and it is light, the cutting volume becomes large for balance correction, and if balance processing is performed Since the shape of the rotor 15 becomes non-uniform and the induced current flowing therethrough changes and the characteristics of the electric motor change, the balance weight is not adjusted by the rotor 15 itself. Therefore, the balance adjustment is performed by the balance ring separately attached to the spindle shaft 1.
A rotor sleeve 16 made of steel is shrink-fitted to the inner circumference of the rotor 15, and the rotor sleeve 16 is used to insert the rotor sleeve 16 into the rotor 15.
15 is fitted to the outer diameter of the spindle shaft 1. The fitting surface has a hydraulic pressure supply recess 17 as a rotor attachment / detachment means for applying hydraulic pressure to expand the inner diameter. This hydraulic supply recess 17
Is connected to a hydraulic pressure supply port 18 which is a screw hole provided on the side surface of the sleeve.

Following the rotor 15, a second balance ring 20 which has been warmed and whose inner diameter has been expanded is also inserted from the rear end side of the spindle shaft 1 and is tightened to the outer diameter of the spindle shaft at a predetermined position somewhat away from the rotor 15. Fixed with. This fixing is also performed by aligning the alignment marks of the second balance ring 20 and the spindle shaft 1 so that they are always in the same phase. The tightening margin inner diameter surface of the second balance ring 20 has a hydraulic chamber 21 as a detaching means for withdrawing the second balance ring 20 by applying hydraulic pressure to expand the inner diameter. When hydraulic pressure is supplied to the hydraulic pressure supply port 22 which is a screw hole provided on the outer diameter surface of the balance ring 20, this hole communicates with the inner surface of the balance ring 20 through the pores, so the hydraulic pressure is applied to the inner surface of the balance ring 20. Supplied and balanced ring 20
Is expanded, the hydraulic pressure communicates with the hydraulic chamber 21, and the balance ring
20 moves to the right due to the hydraulic pressure difference in the hydraulic chamber 21 and can be removed.

Next, the outer cylinder 23 is inserted from the rear end side of the spindle shaft 1, and the front end is fixed to the front bearing housing 6 with a bolt. A stator 25 fixed to a stator sleeve 24 is fitted to the inner diameter surface of the outer cylinder 23, and is arranged circumferentially opposite to the rotor 15. An annular space, which is the cooling jacket 26 of the stator 25, is formed on the inner diameter surface of the stator sleeve 24, and O-ring seals 27 are attached before and after the annular space to prevent leakage of the cooling fluid. The supply / discharge port for the cooling fluid is omitted in the figure.

A rear lid 28 is bolted together with a case 29 to the rear end of the outer cylinder 23. A cylindrical roller bearing 30 is fitted on the inner diameter surface of the rear lid 28 and fixed by an outer ring retainer 31. Cylindrical roller bearing 30
The inner ring 30a is loosely fitted to the outer diameter surface of the spindle shaft 1, and the front side surface of the inner ring is locked to the step portion of the spindle shaft 1. The rear surface of the inner ring 30a is axially pressed by a spacer 32 fitted to the spindle shaft 1.

For example, a detection ring 34 of a magnetic rotary encoder 33 is fitted as a rotational position sensor at the rear end of the spindle shaft 1, and a tightening nut 36 is screwed into a male screw 35 formed at the rear end of the spindle shaft 1. Fixed. Teeth are formed at the same pitch on the outer periphery of the detection ring 34 of the rotary encoder 33, and the read head 37 is attached to and supported by the rear lid 28. Based on the position detection signal of the rotary encoder 33, the rotation of the servomotor including the stator 25 and the rotor 15 is controlled.

Reference numeral 38 is a tip cover, which is bolted to the front bearing housing 6 together with the front lid 8. 39 is a lid at the rear end, which is screwed to the case 29.

 Next, the operation will be described.

The balance correction of this spindle device is performed as follows. First, on the spindle shaft 1, the fixed sleeve 10,
The first balance ring 13, the rotor 15, and the second balance ring 20 are inserted, and the phases are aligned with the alignment marks to temporarily assemble them. In this temporarily assembled state, the imbalance of the spindle shaft 1 and the rotor 15 is inspected. The unbalance is corrected by processing the first balance ring 13 and the second balance ring 20. When the imbalance is corrected, the above-mentioned parts assembled to the spindle shaft 1 are temporarily removed from the spindle shaft 1.

In the case of this disassembly, the hydraulic pressure supply hose from the hydraulic pressure source is connected to the hydraulic pressure supply port 22 of the second balance ring 20, and
Apply hydraulic pressure to 21. This makes the second balance ring
20 is expanded in the radial direction, the tightening force with the spindle shaft 1 is released, and the hydraulic pressure in the hydraulic chamber 21 causes axial hydraulic pressure to move the balance ring 20 to the right in FIG. Can be removed.

The rotor 15 connects a hydraulic pressure supply hose from a hydraulic pressure source to the hydraulic pressure supply port 18 of the rotor sleeve 16 in the same manner, and applies a hydraulic pressure to the hydraulic pressure chamber 17. As a result, the rotor sleeve 16 is expanded in the radial direction and the tightening force with the spindle shaft 1 is released, so that it can be easily attached and detached.

Since the first balance ring 13 is a clearance fit with respect to the spindle shaft 1, a hexagon socket head cap screw which is a detachable means.
It can be easily attached and detached only by removing 14.

The fixed sleeve 10 connects a hydraulic pressure supply hose from a hydraulic pressure source to the hydraulic pressure supply port 12 on the outer surface, and applies a hydraulic pressure to the hydraulic pressure chamber 11. As a result, the diameter of the fixed sleeve 10 is expanded and can be easily attached and detached.

Then, final assembly is performed. At this time, starting from the front bearing block 7, the fixed sleeve 10, the first balance ring 13, the rotor 15, the second balance ring 20, the outer cylinder 23. the cylindrical roller bearing 30, the spacer 32, the detection ring of the rotary encoder 34
Are aligned with the alignment marks and mounted on the spindle shaft 1 as described above. Finally, tighten the tightening nut 36.

Then, fine adjustment of the balance is finally performed in this assembled state. If there is an imbalance, the tightening nut 36 screwed to the rear end of the spindle shaft 1 is removed, and usually the outer diameter of the nut is drilled to correct the imbalance.

Thus, a spindle device that rotates in a very stable balance is obtained.

Also, for example, when the ball bearing 3 wears due to long-term use and the bearing needs to be replaced, the second balance ring 2
Since the 0, the rotor 15, the first balance ring 13, and the fixed sleeve 10 can be easily removed from the spindle shaft 1 from the rear end side, the bearing can be replaced quickly.

Further, since it is not necessary to pull out the bearing toward the tool mounting end side of the spindle shaft 1, that is, toward the front side, the shaft end can be made large in diameter, and a mounting taper hole for fitting the taper shank of the tool can be easily formed. The overall shaft diameter of the spindle shaft 1 can be made smaller and the diameter of the rotor can be made smaller. as a result,
The weight of the spindle shaft 1 is reduced, the moment of inertia is reduced, and the rotation speed can be increased. Furthermore, the motor output has a margin and the motor characteristics have been improved.

In the first embodiment, the balance ring has an inner diameter that is a loose fit with respect to the outer diameter of the spindle and is equipped with a detachable bolt, and a balance ring that has an inner diameter that is a tight fit with respect to the outer diameter of the spindle and is detachable. Although the one provided with the hydraulic pressure supply path for sometimes applying the hydraulic pressure has been described, the present invention is not limited to this, and the point is that it can be easily detached from the spindle.

2 to 5 show another example of the attachment / detachment structure of the balance ring.

The one shown in FIG. 2 is of a so-called spanning ring type, in which the inner diameter surface of the balance ring 40 is a tapered surface 40a and has an inner diameter that slides on the outer diameter of the spindle shaft 1. On the other hand, there is a flanged ring 41 as a wedge member that is fitted to the outer diameter of the spindle shaft 1 by a clearance.
Has a tapered surface. After the balance ring 40 and the flanged ring 41 are sequentially inserted into the spindle shaft 1 and positioned at predetermined positions, the bolts 42 inserted in the flanged ring 41 are screwed into the screw holes of the balance ring 40 and tightened. As a result, the tapered surfaces 40a and 41a are brought into close contact with each other, and the outer diameter surface 41a of the flanged ring 41 is strongly pressed by the slanting action, and the ring inner diameter is reduced and fixed to the spindle shaft 1. When detaching, the bolt 42, which is a detachable screw means, can be easily removed only by loosening.

The structure shown in FIG. 3 has a structure in which a clearance-fitting balance ring 43 is fixed to the spindle shaft 1 with a set screw 44.

In the structure shown in FIG. 4, a key groove 46 is provided on the inner diameter surface of the balance ring 45 and the outer diameter surface of the spindle shaft 1, a key 47 is fitted and positioned in the key groove 46, and a nut screwed to the spindle shaft 1 is used. The structure is fixed at 48.

FIG. 5 shows a structure in which a balance ring 49 is provided with an axial slot 50 and the slot 50 is tightened with a bolt 51.

In either case, since the balance ring can be easily removed from the spindle shaft 1, maintenance work such as bearing replacement can be performed efficiently, and the degree of freedom in designing the spindle shaft 1 is greater than in the past. It can also contribute to improvements in performance such as rotation characteristics and positioning accuracy.

In this embodiment, the detection ring 34 has teeth formed on the outer surface, but it is also possible to use a ring having NS magnetized alternately on the circumferential surface.

[Effect of device]

As described above, according to the present invention, in the spindle device in which the rotatable spindle shaft is supported in the housing by the bearing, the front end portion of the spindle shaft has a portion having a diameter larger than the inner diameter of the bearing. At least one balance ring is detachably attached to the spindle shaft. Therefore, the balance ring once fixed to the spindle shaft can be easily removed, and the effect of facilitating maintenance work such as bearing replacement can be obtained. And, it becomes possible to attach and detach the bearings and other spindle mounting parts only from one end side of the spindle. As a result, the degree of freedom in the layout of the parts assembly to the spindle shaft is increased, and the spindle other than the spindle front end part where the tool is mounted is The diameter can be reduced to reduce the moment of inertia of the whole, and an effect that a highly accurate spindle device can be obtained can be obtained.

[Brief description of drawings]

FIG. 1 is a semi-longitudinal sectional view of an embodiment of the spindle device of the present invention, and FIGS. 2, 3, and 4 are longitudinal sectional views of a main part showing another example of a balance ring attaching / detaching structure, respectively. FIG. 5 is a transverse sectional view of another example. In the figure, 1 is a spindle shaft, 13, 20, 40, 43, 45, 49 are balance rings, and 14, 42, 44, 48, 51 are screw means.

Claims (6)

(57) [Scope of utility model registration request] 1. A spindle device in which a rotatable spindle shaft is supported in a housing by a bearing, and a front end portion of the spindle shaft has a portion having a diameter larger than an inner diameter of the bearing, wherein at least one balance ring is provided. It is fitted to the outer diameter of the spindle shaft with an interference, and a screw hole for connecting to a hydraulic pressure supply hose is provided on the outer surface of the balance ring, and the screw hole communicates with a small hole opened on the inner surface of the balance ring. Spindle device characterized by being provided. 2. A spindle device in which a rotatable spindle shaft is supported in a housing by a bearing, and a front end portion of the spindle shaft has a portion having a diameter larger than an inner diameter of the bearing, wherein at least one balance ring comprises: It is screwed to a sleeve fitted with an interference with the outer diameter of the spindle shaft, and the sleeve has a screw hole for connecting to a hydraulic supply hose on the outer surface and a hole communicating with the screw hole and opening on the inner surface. Spindle device characterized by being. 3. A spindle device in which a rotatable spindle shaft is supported in a housing by a bearing, and a front end portion of the spindle shaft has a portion having a diameter larger than an inner diameter of the bearing, wherein at least one balance ring comprises: A spindle device, wherein the spindle device is fixed to the spindle shaft by a wedge member having an inner surface that slides on the outer surface of the spindle shaft. 4. A spindle device in which a rotatable spindle shaft is supported in a housing by a bearing, and a front end portion of the spindle shaft has a portion having a diameter larger than an inner diameter of the bearing, wherein at least one balance ring comprises: A spindle device, wherein the spindle device is fixed to the spindle shaft with a set screw screwed to the balance ring. 5. A spindle device in which a rotatable spindle shaft is supported in a housing by a bearing, and a front end portion of the spindle shaft has a portion having a diameter larger than an inner diameter of the bearing, wherein at least one balance ring comprises: A spindle device, wherein the spindle device is fixed to the spindle shaft with a nut that is screwed into a screw engraved on the spindle shaft. 6. A spindle device in which a rotatable spindle shaft is supported in a housing by a bearing, and a front end portion of the spindle shaft has a portion having a diameter larger than an inner diameter of the bearing, wherein at least one balance ring comprises: A spindle device comprising a plurality of divided pieces divided by a center line, each divided piece being an annular body coupled by a screw and fastened to the spindle shaft.