JPH0655309A - Spindle supporting device - Google Patents

Abstract

PURPOSE:To simplify the mechanical structure and control circuit for fine movement to effectively reduce cost, etc., while supporting a whole spindle in a non-contact manner. CONSTITUTION:A spindle 1 is supported by non-contact bearings so that it can be moved to either a thrust direction or a radial direction. The bearing to support in moving direction is a magnetic bearing 5, and the bearing to support in fixed direction is a fluid bearing 6. The spindle 1 is supported by the magnetic bearing 5 in a direction required for the movement to, while supporting the whole spindle 1 in a non-contact manner, reduce movement control elements that must be set on a table.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spindle support device applied to support a blade supporting spindle of a machine tool and the like, and more particularly to a spindle support device capable of fine movement with a simple structure.

[0002]

2. Description of the Related Art For example, in a precision grinding machine for making minute cuts, a high-speed rotating spindle, to which a blade such as a grindstone is attached, is precisely controlled to move in a thrust direction or a radial direction. In recent years, non-contact bearings such as fluid bearings and magnetic bearings are often used to support such spindles in order to achieve stable driving and prolong life.

When a fluid bearing is applied to support the spindle, the bearing supporting the spindle is fixed to a movable table, and the position of the blade or the like is controlled by moving the table. On the other hand, when a magnetic bearing is applied, a large number of bearings are arranged in the thrust direction and the radial direction of the spindle, and 5-axis control of the bearing for directly moving and supporting the spindle by magnetic adjustment is performed.

FIG. 5 shows a conventional spindle for performing 5-axis control of such a bearing. As shown in this figure, the spindle 12 has a thrust direction (Z-axis direction).
A metal disk 14 used for displacement control of the magnetic disk is fixed, and a pair of electromagnets 30 for magnetically levitating the spindle in the thrust direction in the Z-axis direction with the metal disk 14 sandwiched therebetween.
Are arranged.

Further, on the circumference of the spindle 12, the spindle 12 is sandwiched in the radial direction (W axis direction, V axis direction).
A pair of magnetic levitation electromagnets 32 and 34 are respectively disposed in. Similarly, the magnetic levitation electromagnets 36 and 38 are arranged to face each other at positions separated from the electromagnets 32 and 34. That is, four of the electromagnets 32, 34 and the electromagnets 36, 38 are arranged at intervals of 90 ° on the circumference of the spindle 12 as a center.
4, 36, 38 magnetically levitates the spindle 12 in the radial direction.

Then, each electromagnet 30, 32, 34, 3
Sensors 40, 42, 44, 46 and 48 for detecting the displacement of the spindle 12 are arranged at the respective proximity positions 6 and 38. Each of these electromagnets and sensors is connected to a controller (not shown). Then, the current supplied to the electromagnet 30 is changed so that the metal disk 14 when the spindle 12 is magnetically levitated will be at a predetermined position based on the detection signal from the sensor 40.

Further, when the spindle 12 is magnetically levitated, the electromagnet 32 is arranged so that the magnetically levitated spindle 12 is at a predetermined position in the V direction and the W direction based on the detection signals from the sensors 42, 44, 46 and 48. , 34, 36, 3
The 5-axis control for the spindle 12 is performed by changing the current supplied to the spindle 8.

[0008]

However, in most cases, the fluid bearing and the magnetic bearing are individually applied in the related art, which causes various problems. For example, in the case of using a fluid bearing, even the minute movement of the spindle has to rely on the movement control of the table, which complicates the structure.

When a magnetic bearing is used, the feed of the spindle itself can be controlled by directly controlling the current supplied to the electromagnets 30, 32, 34, 36, 38, so that a mechanical structure is provided. Is relatively simple, but the control circuit is complicated and the manufacturing cost is considerably high.

Particularly in precision machining, it is necessary to consider the origin alignment of the blade, adjustment for thermal expansion during the work of the spindle, etc., and it is necessary to perform extremely precise fine movement control. Therefore, the above-described mechanical structure and complication of the control circuit are serious problems.

The present invention has been made in order to solve such a problem, and while supporting the entire spindle in a non-contact manner, it is possible to simplify the mechanical structure and the control circuit relating to the minute movement, and reduce the cost. An object of the present invention is to provide a spindle support device that can be effectively aimed.

[0012]

In order to achieve such an object, the present invention provides a spindle support device for movably supporting a spindle in either a thrust direction or a radial direction by a non-contact bearing. The bearing that supports the above is a magnetic bearing, and the bearing that supports in the fixed direction is a fluid bearing.

[0013]

The movement of the blade supporting spindle, which is generally set for cutting in a machine tool or the like, is sufficient in either the thrust direction or the radial direction. Therefore, according to the configuration of the present invention described above, by supporting the spindle in the direction necessary for its movement by the magnetic bearing, the movement control element to be set on the table or the like without losing the advantage of non-contact support of the entire spindle. Can be reduced.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the spindle support device of the present invention will be described below with reference to FIGS. FIG. 1 shows the basic structure of a spindle support device, and FIG. 2 is for explaining the operation thereof.

The spindle supporting device of this embodiment is applied to a grindstone supporting spindle of a grinding device, and a blade 2 is attached to the tip of the spindle 1. As the blade 2, for example, a cup grindstone, which is processed by moving in the thrust direction, is attached. The spindle 1 and the blade 2 are rotatably driven by a rotation mechanism (not shown) such as a motor.

A magnetic bearing 5 is arranged as a bearing for movably supporting the spindle 1 in the thrust direction. The magnetic bearing 5 is composed of a metal disk 3 provided on the spindle 1 and thrust electromagnets 4 arranged on opposite sides of the metal disk 3. Then, similar to the conventional spindle support device described with reference to FIG. 5, the spindle 1 is placed at the position near the thrust electromagnet 4.
A thrust position sensor (not shown) for detecting the displacement of the thrust direction is disposed.

On the other hand, as a bearing for fixedly supporting the spindle 1 in the radial direction, a hydrodynamic bearing 6 composed of a hydrostatic bearing or a hydrostatic bearing such as an air bearing or a hydraulic bearing is arranged. With such a configuration, when the blade 2 such as a cup grindstone is advanced in the thrust direction, as shown by an arrow a in FIG. 1, for example, while the position of the spindle 1 is being detected by a thrust position sensor (not shown), The spindle 1 can be moved by adjusting the current supplied to the thrust electromagnet 4 of the bearing 5. As a result, the state shown in FIG. 2 can be achieved, and similarly, by adjusting the current supplied to the thrust electromagnet 4, the spindle 1 can be retracted to the original position.

Therefore, according to such a spindle support device, the movement of the spindle 1 in the thrust direction can be performed with a simple structure without losing the advantage of non-contact support of the entire spindle. It is possible to simplify the mechanical structure and control circuit for the above, and effectively achieve cost reduction.

3 and 4 show a spindle support device according to another embodiment of the present invention. FIG. 3 shows the basic structure of the spindle support device.
Is for explaining the action. In this spindle support device, the blade 2 installed at the tip of the spindle 1 is equipped with, for example, a cylindrical grindstone or an outer peripheral grindstone, which is processed by the movement in the radial direction.

In this spindle support device, contrary to the spindle support device shown in FIGS. 1 and 2, the fluid bearing 9 fixedly supports the spindle 1 in the thrust direction, and the magnetic bearing 1
1 supports the spindle 1 movably in the radial direction. That is, the fluid bearing 9 supported in the thrust direction includes the metal disk 7 provided on the spindle 1 and the bearing members 8 arranged on both sides of the metal disk 7.
It consists of

On the other hand, the magnetic bearing 1 supported in the radial direction
Reference numeral 1 is composed of a plurality of radial electromagnets 10 arranged on the circumference of the spindle 1 so as to face each other with the spindle 1 interposed therebetween. A radial position sensor (not shown) that detects the displacement of the spindle 1 in the radial direction is also arranged in the vicinity of the radial electromagnet 10.

According to this structure, when the blade 2 such as a cylindrical grindstone is moved in the radial direction as shown by an arrow b in FIG. 3, the position of the spindle 1 is detected by a radial position sensor (not shown). Meanwhile, the spindle 1 is moved by adjusting the current supplied to the radial electromagnet 10 of the magnetic bearing 11. As a result, the state shown in FIG. 4 can be obtained.

Therefore, according to this embodiment, the spindle 1
Can be moved in the radial direction with a simple structure without losing the advantage of non-contact support of the entire spindle, and similarly to the above, the mechanical structure and control circuit for minute movement can be simplified.

[0024]

As described above, according to the present invention, the support in the direction necessary for the movement of the spindle is supported by the magnetic bearing, and the support in the fixed direction is supported by the fluid bearing. It is possible to reduce the number of moving elements while supporting the formula, simplify the mechanical structure and control circuit for moving, and effectively reduce the cost.

[Brief description of drawings]

FIG. 1 is a basic configuration diagram showing an embodiment of the present invention.

FIG. 2 is an explanatory view of the operation of the one embodiment.

FIG. 3 is a basic configuration diagram showing another embodiment of the present invention.

FIG. 4 is an operation explanatory view of the other embodiment.

FIG. 5 is a schematic configuration diagram of a conventional spindle support device that performs 5-axis direction control.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Spindle 2 Blades 3, 7 Metal disk 4 Thrust electromagnet 5,11 Magnetic bearing 6,9 Fluid bearing 8 Bearing member 10 Radial electromagnet

Claims (1)

[Claims] 1. A spindle support device for supporting a spindle movably in either a thrust direction or a radial direction by a non-contact bearing, wherein a bearing for supporting the moving direction is a magnetic bearing, and a bearing for supporting the fixed direction. A spindle support device characterized by being a fluid bearing.