JPH03125017A - Magnetic control bearing unit - Google Patents

Abstract

PURPOSE:To damp the vibration of a rotational shaft by having a middle seat sandwiched by a magnetic pole face of an electromagnet and an outer peripheral surface of a bearing holder, and by providing an acceleration sensor that detects vibrational acceleration transmitted to the bearing holder. CONSTITUTION:A rotational shaft is inserted in the inside of a rolling bearing 3, which is supported by a bearing holder 10 made of magnetic material. Around the bearing holder 19, plural electromagnets 22a-22d are arranged. A middle seat 24 made of non-magnetic material is sandwiched between a magnetic pole surface of each electromagnet 22a-22d and an outer peripheral surface of the bearing holder 19. A controller is provided so as to control electrification to each electromagnet 22a-22d, based on a signal from an acceleration sensor that detects vibrational acceleration transmitted to the bearing holder 19. The vibration of each rotational shaft is thus damped, and the growth of the vibration can thus be prevented.

Description

Detailed Description of the Invention (Field of Industrial Application) The magnetically controlled bearing unit according to the present invention is used in various machine tools, etc. to rotate a rotating shaft with a large dynamic hand balance or a rotating shaft that rotates at high speed. It is used to rotatably support a shaft while suppressing vibration, or to rotatably support a member that receives a large impact load, such as a steel rolling roller.

(Prior art) For example, in the case of a rotating shaft with a large dynamic hand balance or a rotating shaft that rotates at high speed, it often vibrates as it rotates, but if no measures are taken to suppress this vibration, this may occur due to resonance etc. The vibrations gradually grow, and in severe cases, it becomes impossible to operate machine tools equipped with rotating shafts.

For this reason, as seen in, for example, Japanese Unexamined Utility Model Publication No. 62-77322 and Japanese Unexamined Patent Publication No. 63-135612,
Devices are known for damping vibrations of a rotating shaft by mechanical means or by viscous fluid means.

Among these, disclosed in Japanese Utility Model Application Publication No. 62-77322,
A mechanically vibration-isolated 'type bearing unit is constructed as shown in FIGS. 3 and 4.

In Figs. 3 and 4, 1 is a rotating shaft, and a bearing holder 2
It is rotatably supported inside via a rolling bearing 3. The bearing holder 2 is supported inside the bearing casing 4 via a damper member 5.

The damper member 5 made of an elastic material has a plurality of outer convex portions 7.7 and a plurality of inner convex portions 8.8 on the outer circumferential surface and inner circumferential surface of the short cylindrical main portion 6, respectively, in a staggered manner. The outer protrusions 7.7 are elastically pressed against the inner circumferential surface of the bearing casing 4, and the inner protrusions 8.8 are elastically pressed against the outer circumferential surface of the bearing holder 2. There is.

As a result, in the case of the vibration-proof bearing unit shown in FIGS. 3 and 4, even when the rotating shaft 1 vibrates, the main portion 6 of the damper member 5 elastically deforms to absorb the vibration. Prevent this vibration from growing.

Further, a vibration-proof bearing unit using viscous fluid means disclosed in Japanese Patent Application Laid-open No. 135612/1983 is constructed as shown in FIG.

In this FIG. 5, 9.9 is a pair of viscous fluid dampers provided with the rotating shaft 1 in between, and each viscous fluid damper 9.9
, each of which is compressed by a compression spring 10.10,
The piston 11.1 is elastically biased toward the outer circumferential surface of the piston 11.1.
1 is built-in. A sliding contact piece 13.13 is provided at the tip end of the rod 12.12 whose base end is connected to each piston 11.11, and each sliding contact piece 13.13 is moved by the elasticity of the compression spring 10. , is pressed against the outer peripheral surface of the rotating shaft 1. Further, a thermo module 1 is installed in the middle of the pipe 14.14 connecting the pair of viscous fluid dampers 9.9.
5.15 etc., so that the temperature of the viscous fluid flowing inside the pipe 14.14 can be adjusted.

Since it is configured as described above, even if the rotating shaft 1 vibrates, this vibration is caused by the pistons 11.11 incorporated in the pair of viscous fluid dampers 9.9 trying to displace in the viscous fluid. It is absorbed and the vibration of the rotating shaft 1 is prevented from growing.

When adjusting the vibration damping performance of the pair of viscous fluid dampers 9.9, the viscosity of the viscous fluid is changed by raising and lowering the temperature of the viscous fluid using the thermo module 15.15.

(Problems to be Solved by the Invention) However, in the case of the conventional anti-vibration bearing unit that is configured and operates as described above, the following disadvantages occur.

That is, since the magnitude, frequency, etc. of the vibrations of the rotating shaft 1 vary depending on the operating conditions of the machine tool, etc. in which the rotating shaft 1 is incorporated, it is preferable that the performance of damping the vibrations of the rotating shaft 1 is also adjustable. .

However, in the case of the 8a mechanical type as shown in Figures 3 and 4, not only is it impossible to adjust the vibration damping performance afterwards, but the bearing rigidity (-load capacity/displacement) itself is sufficiently large. Therefore, it could not be used in parts that are subject to large impact loads, such as rolling rollers.

In addition, in the case of the viscous fluid type shown in Fig. 5, although it is possible to adjust the vibration damping performance later, it takes time to change the temperature of the viscous fluid using the thermo modules 15, 15, so the rotation The responsiveness when the vibration condition of the shaft 1 suddenly changes cannot necessarily be said to be sufficient.

The magnetically controlled bearing unit of the present invention eliminates all of the above-mentioned disadvantages.

(Means for Solving the Problems) Each magnetically controlled bearing unit of the present invention includes a bearing into which a rotating shaft is inserted, a bearing holder made of a magnetic material that supports this bearing inside, and a surrounding area around the bearing holder. The bearing holder includes a plurality of electromagnets arranged in the bearing holder, an acceleration sensor that detects vibrational acceleration transmitted to the bearing holder, and a controller that controls energization of each of the electromagnets based on a signal from the acceleration sensor.

In the magnetically controlled bearing unit according to the first aspect, a spacer made of a non-magnetic material is sandwiched between the magnetic pole surface of each electromagnet and the outer peripheral surface of the bearing holder.

Further, in the magnetically controlled bearing unit according to the second aspect of the present invention, a film made of a non-magnetic material is formed on the outer peripheral surface of the bearing holder.

Furthermore, the magnetically controlled bearing unit according to claim 3 includes:
A coating made of a non-magnetic material is formed on the magnetic pole surface of each electromagnet.

(Function) The magnetically controlled bearing unit of the present invention configured as described above attenuates the vibration of the rotating shaft and prevents the vibration from growing.The function is as follows.

When the rotating shaft inserted inside the bearing supported by the bearing holder vibrates, the acceleration sensor detects the acceleration of this vibration and sends this detection signal to the controller.

Then, the controller energizes the electromagnet based on the detection signal to pull the bearing holder in a direction opposite to the direction in which the rotating shaft vibrates.

As a result, the kinetic energy of the rotating shaft due to vibration and the kinetic energy based on the attractive force of the electromagnet cancel each other out, damping the vibration of the rotating shaft and preventing the vibration from growing.

(Example) Next, the present invention will be explained in more detail while explaining the illustrated embodiment.

1 and 2 show examples of the present invention, FIG. 1 is a view corresponding to the AA cross section in FIG. 2, and FIG. 2 is a view corresponding to the B--
It is a sectional view of B.

3.3 is a rolling bearing in which a rotating shaft 1 (see Figs. 3 and 4; omitted in Figs. 1 and 2) is inserted inside each bearing; an inner ring raceway formed on the outer peripheral surface of an inner ring 16 and an outer ring 17; A plurality of rolling elements 18.18 are provided between the outer ring raceway formed on the inner peripheral surface of the inner ring 16.16, and the rotating shaft 1 is inserted inside the inner ring 16. There is.

A pair of rolling bearings 3.3 as described above have their respective outer rings 17.17 fitted into the bearing holder 19, and the retaining nuts 20
It is supported inside this bearing holder 19 by preventing it from being pulled out.

The bearing holder 19 is made of a magnetic material such as steel and has a cylindrical shape.
The inner circumferential surface is cylindrical, and the outer circumferential surface is a square tube in which the first, second, third, and fourth planes 21 a, 2 l b, 21 c, and 21 d are continuous, and the rolling bearing 3 .3
The outer rings 17, 17 of the bearing holder 19 are each fixedly fitted in this bearing holder 19.

On the other hand, a rectangular frame-shaped housing 25 is provided around the bearing holder 19 so as to surround the bearing holder 19. And on the inner peripheral surface of this housing 25,
First to fourth electromagnets 22 a, 22 b, respectively.
22 c and 22 d are the respective electromagnets 22 a to 2
The magnetic pole surface at the inner end of 2d is aligned with the first to fourth planes 21a to 2d.
21d.

Furthermore, a first acceleration sensor (not shown) is attached to the first flat surface 21a of the outer peripheral surface of the bearing holder 19,
A second acceleration sensor 23 is attached to a second plane 21b adjacent to the first plane 21a.

On the other hand, between the magnetic pole surfaces of the first to fourth electromagnets 22a to 22d and the first to fourth planes 21a to 21d that constitute the outer peripheral surface of the bearing holder 19, aluminum, synthetic resin, etc. A spacer 24 made of non-magnetic material is sandwiched therebetween.

Furthermore, in the case of the magnetically controlled bearing unit of the present invention, the detection signals of the first and second acceleration sensors 23 are input to a controller (not shown), and the controller controls the electromagnets based on the detection signals. Electricity is supplied at a voltage corresponding to the magnitude of the acceleration signal.

With the magnetically controlled bearing unit of the present invention configured as described above, a pair of rolling bearings 3.
The operation of damping the vibration of the rotary shaft 1 rotatably supported via the rotary shaft 1 and preventing the vibration from growing is as follows.

When the rotating shaft 1 vibrates, this vibration causes the inner ring 16.16 and the rolling elements 18.18 that constitute a pair of rolling bearings 3.3 to vibrate.
, is transmitted to the bearing holder 19 via the outer ring 17.17, and this bearing holder 19 generates an acceleration in the same direction as the rotation @1 and vibrates.

The acceleration (direction and magnitude) of such vibration of the bearing holder 19 is detected by one or both of the first acceleration sensor and the second acceleration sensor 23, and a detection signal representing this detected value is used for control. sent to the vessel.

Based on the detection signal, the controller energizes the first to fourth electromagnets 22a to 22d to move the bearing holder 19, into which the rotating shaft 1 is inserted, in the direction in which the rotating shaft 1 is about to be displaced based on the vibration. pull in the opposite direction.

For example, at the moment when the rotating shaft 1 is about to move to the right in FIG. 1 due to vibration, the controller, based on the signal from the first acceleration sensor, The amount of current supplied to the first electromagnet 22c is increased, and the amount of current supplied to the first electromagnet 22a provided on the right side of the figure is decreased (including stopping the supply of current). The bearing holder 19 supporting the holder 19 tends to be pulled to the left in the figure. At this time, the amount of current applied to the first and third electromagnets 22a and 22c is adjusted based on the vibration acceleration of the bearing holder 19 detected by the first acceleration sensor.

At the moment when the rotating shaft 1 is about to shift to the left in FIG. 1, the controller reduces the amount of current applied to the third electromagnet 22c, and reduces the amount of current applied to the first electromagnet 22a on the opposite side. is increased to tend to pull the bearing holder 19 to the right in the figure.

As a result, the kinetic energy of the rotating shaft 1 due to vibration and the kinetic energy based on the attractive force of the third electromagnet 22C1 and the first electromagnet 22a cancel each other out, and the rotating shaft 1
This damps the vibrations and prevents them from growing.

When the rotating shaft 1 vibrates in the vertical direction in FIG. 1, this vibration is damped by appropriately energizing the second and fourth electromagnets 22b and 22d, and the rotating shaft 1 further vibrates in an oblique direction. In this case, this vibration is attenuated by appropriately energizing the first to fourth electromagnets 22a to 22d.

In this way, since the action of damping vibrations by the first to fourth electromagnets 22a to 22d is performed electrically, the rotating shaft 1
Even if the vibration state of the device suddenly changes, it is possible to immediately respond to this change.

In particular, in the case of the magnetically controlled bearing unit of the present invention, the magnetic pole surfaces of the first to fourth electromagnets 22a to 22d and the bearing holder 19
Since the spacer 24 made of non-magnetic material is interposed between the first to fourth planes 21a to 21d, each electromagnet 22a to 2
2d and the bearing holder 19 do not move together, and the vibration of the bearing holder 19 can be reliably damped by controlling the energization to each of the electromagnets 22a to 22d.

However, the gap between the first to fourth planes 21a to 21d and the magnetic pole faces of the first to fourth electromagnets 22a to 22d, in which the spacer 24 is sandwiched, is approximately several hundred μm. Since the gap is narrow, in order to interpose a layer made of a non-magnetic material between each surface, instead of providing the spacer 24 made of a non-magnetic material in the above-mentioned gap, the first to fourth planes 21a to 21. 21d and the first ~
A film made of a non-magnetic material may be formed on one or both of the magnetic pole faces of the fourth electromagnets 22a to 22d to close the gap.

Note that each acceleration sensor for detecting vibration acceleration transmitted to the bearing holder 19 may be attached to the housing 25.

Further, the outer peripheral surface of the bearing holder 19 may be a cylindrical surface instead of a square cylindrical surface.

(Effects of the Invention) The magnetically controlled bearing unit of the present invention is configured and operates as described above, but since the vibrations generated in the rotating shaft are damped by the electromagnet, it is possible to effectively prevent vibrations in different conditions. Even if the vibration state suddenly changes, it is possible to respond quickly, and machine tools equipped with rotating shafts can always be operated in a stable state.

Further, the outer ring constituting the rolling bearing has first to fourth electromagnets made of a material having sufficient rigidity, a spacer or membrane made of a non-magnetic material, and a bearing holder in the housing. Since it is held through the bearing, the bearing rigidity is sufficient, and it can be used in parts that are subject to large impact loads, such as rolling rollers.

[Brief explanation of the drawing]

1 and 2 show examples of the present invention, FIG. 1 is a view corresponding to the AA cross section in FIG. 2, and FIG. 2 is a view corresponding to the B--
3 and 4 show a first example of a conventional bearing unit, FIG. 3 is a vertical sectional view, FIG. 4 is a half vertical sectional view of FIG. 3, and FIG. 5 is a conventional bearing unit. It is a sectional view showing a second example of the device. DESCRIPTION OF SYMBOLS 1: Rotating shaft, 2: Bearing holder, 3: Rolling bearing, 4: Bearing casing, 5: Damper member, 6: Main part, 7: Outer convex part, 8: Inner convex part, 9: Viscous fluid damper, 10: Compression spring, 11: Piston, 12: Rod, 13: Sliding piece, 1
4: Pipe, 15: Thermo module, 16: Inner ring, 17:
Outer ring, 18: Rolling element, 19: Bearing holder, 20: Lock nut, 21a: First plane, 21b: Second plane, 21
C: third plane, 21d: fourth plane, 22a: first electromagnet, 22b: second electromagnet, 22C: third electromagnet, 22d: fourth electromagnet, 23: first acceleration sensor,
24: Spacer, 25: Housing.

Claims (3)

[Claims] (1) A bearing into which a rotating shaft is inserted, a bearing holder made of magnetic material that supports this bearing inside, a plurality of electromagnets arranged around this bearing holder, the magnetic pole surface of each electromagnet, and the above bearing. A spacer made of non-magnetic material is sandwiched between the outer peripheral surface of the holder, an acceleration sensor that detects the vibration acceleration transmitted to the bearing holder, and energization of each of the electromagnets based on the signal from this acceleration sensor. A magnetically controlled bearing unit comprising a controller for controlling the magnetically controlled bearing unit. (2) A bearing into which a rotating shaft is inserted, a bearing holder made of magnetic material that supports this bearing inside, and a plurality of electromagnets arranged around this bearing holder, and vibration acceleration transmitted to the bearing holder. The magnetic bearing holder includes an acceleration sensor for detecting the acceleration, and a controller for controlling energization of each of the electromagnets based on the signal from the acceleration sensor, and a coating made of a non-magnetic material is formed on the outer peripheral surface of the bearing holder. Control bearing unit. (3) A bearing into which a rotating shaft is inserted, a bearing holder made of magnetic material that supports this bearing inside, and a plurality of electromagnets arranged around this bearing holder, and vibration acceleration transmitted to the bearing holder. A magnetic device comprising an acceleration sensor for detecting the acceleration, and a controller for controlling the energization of each of the electromagnets based on a signal from the acceleration sensor, and a coating made of a non-magnetic material is formed on the magnetic pole surface of each of the electromagnets. Control bearing unit.