JPH10191667A - Oscillation type driving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the load to be borne by a part of bearings from being increased in an oscillation type driving device. SOLUTION: In an oscillation type driving device provided with an oscillating body 2 by which the oscillation is excited, a moving body 3 which is brought into contact with the oscillating body and driven, a pressing member 6 to connect the moving body to an output shaft 4, and to pressingly bring the moving body into contact with the oscillating body, and a plurality of bearing members (e.g. roller bearing) 81, 82 to rotatably support the output shaft, the press reaction by the pressing member 6 is borne by a plurality of bearing members 81, 82 through the output shaft, and in addition, the press reaction to be borne respective is used as the internal pre-load of the bearing members 81, 82.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration type driving device for obtaining a driving force by bringing a moving body into pressure contact with a vibrating body.

[0002]

2. Description of the Related Art A vibration-type driving device (vibration-type motor) brings a moving body into pressure contact with a vibrating body made of an elastic member to which an electro-mechanical energy conversion element is joined, and applies an AC voltage to the conversion element. The moving body is driven by friction by generating a progressive vibration wave in the vibrating body.

FIG. 7 shows a conventional vibration type motor. A connector 110 is provided on the lower surface of a ring-shaped stator (vibrating body) 102 fixed to a base 101 and an elastic body 121.
And the electro-mechanical energy conversion element 122 energized through the flexible substrate 111 and the elastic body 121.
A friction member 123 is adhered to the upper surface of the first member. The outer periphery of a pressure spring 106 is attached to the upper surface of the rotor (moving body) 103 via a rubber plate 107, and the inner periphery of the pressure spring 106 is attached to a disk 105 shrink-fitted to an output shaft 104. Have been.

The output shaft 104 is rotatably supported by a pair of rolling bearings 181 and 182 having an outer ring fixed to the base 101 and an inner ring fitted on the outer periphery of the output shaft 104. The disk 105 is in contact with the inner ring of the rolling bearing 182. On the other hand, the inner ring of the rolling bearing 181 has the output shaft 1 together with the inner ring of the disk 105 and the rolling bearing 182 by the amount of displacement of the pressure spring 106 for bringing the rotor 103 into press contact with the stator 102 with an appropriate force.
04 with the output shaft 1 pushed into the stator 102 side.
It is engaged with the snap ring 109 attached to the groove of No. 04.

As a result, as shown in FIG.
2, the pressing spring 106 is applied to the inner ring by the disk 105.
A preload in the same direction as the pressing force is applied, and the radial play in the bearing 182 is eliminated. On the other hand, in the bearing 181, a preload is applied to the inner ring by the snap ring 109 in a direction opposite to the pressing force of the pressing spring 106, and the radial direction in the bearing 182 is eliminated. In this way, since the radial directions of the bearings 181 and 182 are eliminated, the radial deviation of the output shaft 104 can be suppressed.

Here, the pressure reaction force of the pressure spring is F, and the bearing 1
Assuming that the preload of 81 is P1 and the preload of the bearing 182 is P2, a relationship of F = P1-P2 is established between these three forces.

As can be seen from this, since the bearing 181 receives the sum of the pressure reaction force and the preload of the bearing 182 as the preload, the preload becomes extremely larger than the preload of the bearing 182.

[0008]

Generally, the fatigue life of a bearing is inversely proportional to the cube of the bearing load. Therefore, the fatigue life of the bearing 181 subjected to a large preload is extremely shorter than that of the bearing 182. Further, since the vibration type motor is often used at a low speed and an oil film is not easily formed between the rolling element of the bearing and the raceway surface, it is necessary to reduce the load of the rolling element of the bearing as compared with usual.

[0009] The torque that can be generated by the motor depends on the maximum frictional force between the stator and the rotor. Since this frictional force is determined by the friction coefficient between the rotor and the stator and the pressing force, it is effective to increase the pressing force when increasing the maximum torque.

However, in the conventional motor, since the bearing 181 bears all the pressing force, a bearing having a larger rated load must be used to increase the pressing force without shortening the life of the bearing. And expensive.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a vibration-type drive device which can extend the life of a bearing, and hence the life of a drive device, and can use a bearing having a small rated load to save cost and space.

[0012]

In order to achieve the above object, according to the present invention, there is provided a vibrating body in which vibration is excited, a moving body driven in contact with the vibrating body, and a moving body and an output shaft. And a plurality of bearing members (for example, rolling bearings) that rotatably support the output shaft, and a pressurizing member that pressurizes and contacts the moving body and the vibrating body. The pressure reaction force by the pressure member is borne by the plurality of bearing members via the output shaft, and the pressure reaction force borne by each is used as the internal preload of each bearing member.

In other words, the preload direction of each bearing is made equal and the same direction as the pressing reaction force, so that the pressing reaction force, which was conventionally borne by one bearing, is dispersed as a preload to a plurality of bearings. In this way, the life of the bearing and hence the drive unit can be extended.

The pressure reaction force is applied to a plurality of bearing members in accordance with the ratio of the rated load of each bearing member, or the reaction force between the rolling surface and the rolling element of each bearing member (rolling bearing) is controlled. It is desirable to extend the life of the drive device by sharing the contact surface pressure so that the bearings have substantially the same life.

As a specific configuration, each inner ring of the plurality of rolling bearings and the output shaft are integrally and movably connected in the direction in which the pressure reaction force acts on the output shaft. In this case, a plurality of rolling bearings may be arranged on both sides in the axial direction of the output shaft with the pressing means interposed therebetween.

Further, an inner ring of a predetermined rolling bearing and an output shaft of the plurality of rolling bearings are integrally movably connected in a direction in which a pressure reaction force acts on the output shaft. A spring is arranged between the other rolling bearing and the inner ring. In this case, the displacement of the spring is applied to each rolling bearing,
The pressure reaction force may be set so as to be shared according to the ratio of the rated load of each of the rolling bearings, or may be set so that the contact surface pressure between the raceway surface of each rolling bearing and the rolling element is equal.

Further, the rolling elements of the plurality of rolling bearings may be configured to roll a track groove formed on the outer periphery of the output shaft.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) FIG. 1 shows a vibration type driving device according to a first embodiment of the present invention. The ring-shaped metal stator (vibration body) 2 fixed to the base 1 is an elastic body 2
1, a connector 10 and a flexible substrate 11
An electro-mechanical energy conversion element 22 that is energized through the elastic member 21 is joined, and a friction member 23 is adhered to the upper surface of the elastic body 21. A rubber plate 7 is provided on the upper surface of the rotor (moving body) 3.
The outer peripheral portion of the pressure spring 6 is attached via a through hole, and the inner peripheral portion of the pressure spring 6 is attached to the disk 5 shrink-fitted to the output shaft 4.
Attached to.

The output shaft 4 is rotatably supported by a pair of deep groove ball bearings (rolling bearings) 81, 82 having an outer ring fixed to the base 1 and an inner ring fitted on the outer periphery of the output shaft 4.

An inner ring of each of the bearings 81 and 82 has a pressure spring 6 for bringing the rotor 3 into pressure contact with the stator 2 with an appropriate force.
The disk 5 and the output shaft 4 by the amount of displacement of the stator 2
Side, and the bearings 81,
82 is engaged with a snap ring 9 mounted in a groove formed on the lower side. Thus, the output shaft 4 and the inner rings of the bearings 81 and 82 can move integrally with each other in the direction in which the pressure reaction force from the pressure spring 6 to the output shaft 4 acts. In addition,
The disk 5 is separated from the inner and outer rings of the bearing 82.

A wave washer 12 is interposed between the inner ring of the bearing 82 and the snap ring 9 engaged with the inner ring. The amount of deformation of the wave washer 12 is set to the amount of deformation in which the reaction force component acts on the inner ring of the bearing 82 when the above-described press reaction force is proportionally distributed to the ratio between the rated loads of the bearings 81 and 82.

By applying a pressing reaction force to the inner rings of the bearings 81 and 82 via the output shaft 4 and the snap ring 9 as described above, the reaction force components borne by the respective bearings 81 and 82 are reduced.
1,82 will be used as preload. In this way, since the radial directions of the bearings 81 and 82 are eliminated, the radial deviation of the output shaft 4 can be suppressed.

Here, the relationship between the preloads of the bearings 81 and 82 will be described in detail with reference to FIG. FIG. 5 schematically shows the bearings 81 and 82, in which the rotor 3, the stator 2, and the pressure spring 6 are omitted.

The pressure reaction force F acts as an upward force on the output shaft 4, and the pressure reaction force F is applied to the two bearings 8.
1 and 82, and the preloads of the bearings 81 and 82 are P1 and P2, respectively.

Here, the preload P2 is determined by each bearing 8 during pressurization.
The spring force for the deformation of the wave washer 12, which is determined by the difference between the axial movement amounts of the inner rings 1, 82, the relative positions of the outer rings, and the interval between the two snap rings 9, 9 applied to the output shaft 4, is equal to the spring force.

Since the directions of the preloads P1 and P2 of the bearings 81 and 82 are equal and the same direction as the pressing reaction force F,
The preload P1 of 1 is a value obtained by subtracting the preload P2 of the bearing 82 from the magnitude of the pressing reaction force. As a result, the pressing reaction force F
Can be distributed to the two bearings 81 and 82 as preload.

It has been empirically known that the fatigue life of a ball bearing is expressed by the following equation.

L∝ (C / P) ³ where L: life, C: basic dynamic load rating of bearing, P: bearing load When a plurality of bearings are used, the shortest bearing life is the life of the drive unit. By setting the conditions such that the life of each bearing is substantially equal, the life of the drive device can be extended. For this purpose, from the above equation, the rated load C of each of the bearings 81 and 82 can be calculated.
The pressure reaction force F may be proportionally distributed to the ratio of the rated loads of the bearings 81 and 82 so that the ratio between the bearing load P and the bearing load P is equal to each bearing load (preload).

In this embodiment, the distance between the snap rings 9 and the position of the bearing outer ring may be determined so as to give a deformation amount of the wave washer 12 for generating a bearing load in which the press reaction force F is proportionally distributed. .

When the contact surface pressure between the raceway surface of the bearing and the rolling element is large when the bearing is stationary or rotating at extremely low speed, permanent deformation occurs on the raceway surface and the rolling element, and the bearing cannot be used. There is a risk.

For this reason, the pressure reaction force is set so that the safety coefficient f expressed by the ratio f = C ₀ / P ₀ between the basic static load C ₀ of the bearing and the static load P _{0 on} the bearing is equalized. What is necessary is just to make each bearing load proportionally distributed to the ratio of the rated load of each bearing.

Strictly speaking, since the contact surface pressure between the raceway surface and the rolling element is not proportional to the bearing load, the bearing load is adjusted so that the contact surface pressure between the raceway surface and the rolling element becomes equal in each bearing. May be allocated.

(Second Embodiment) FIG. 2 shows a vibration type driving device according to a second embodiment of the present invention. A ring-shaped metal stator (vibrator) 2 fixed to the base 1
An electro-mechanical energy conversion element 22 energized through the connector 10 and the flexible substrate 11 is joined to the lower surface of the elastic body 21, and a friction member 23 is bonded to the upper surface of the elastic body 21. An outer peripheral portion of a pressure spring 6 is mounted on the upper surface of the rotor (moving body) 3 via a rubber plate 7, and an inner peripheral portion of the pressure spring 6 is mounted on a disk 5 shrink-fitted on the output shaft 4. Have been.

The output shaft 4 is provided with a pressure spring 6 on the base 1.
And a pair of deep groove ball bearings (rolling bearings) 81 and 82 having an outer ring fixed at a position sandwiching the disk 5 and an inner ring fitted on the outer periphery of the output shaft 4.

The inner ring of the bearing 81 is connected to the rotor 3 by the stator 2.
The disk 5 and the output shaft 4 are formed on the lower side of the bearing 81 of the output shaft 4 in a state where the disk 5 and the output shaft 4 are pushed toward the stator 2 by an amount corresponding to the displacement amount of the pressure spring 6 for pressurizing contact with an appropriate force. Engaged with the snap ring 9 mounted in the groove. The inner ring of the bearing 82 is in contact with the upper surface of the disk 5 with the wave washer 12 interposed therebetween. This allows
The output shaft 4 and the inner races of the bearings 81 and 82 can move integrally with respect to the direction of action of the pressure reaction force from the pressure spring 6 to the output shaft 4.

The amount of deformation of the wave washer 12 is set to the amount of deformation in which the reaction force component acts on the inner ring of the bearing 82 when the above-mentioned pressure reaction force is proportionally distributed to the ratio between the rated loads of the bearings 81 and 82. I have.

In this embodiment, two bearings 81,
By applying a preload in the same direction in which the pressing reaction force is proportionally distributed to the ratio of the rated load to the bearing 82, the pressing reaction force is applied to the bearings 81 and 82.
As a result, the life of the drive device can be extended.

Further, the two bearings 81 and 82 are
Further, by providing the disk 5 (that is, the rotor 3 and the stator 2) at the position, the distance between the bearings can be increased, and the rigidity of the output shaft 4 against the radial load can be increased.

(Third Embodiment) FIG. 3 shows a third embodiment of the present invention.
1 shows a vibration type driving device according to an embodiment. Base 1
Ring-shaped metal stator (vibrator) 2 fixed to
Is connected to an electro-mechanical energy conversion element 22 energized through the connector 10 and the flexible substrate 11 on the lower surface of the elastic body 21, and the friction member 23
It is configured by bonding. An outer peripheral portion of a pressure spring 6 is mounted on the upper surface of the rotor (moving body) 3 via a rubber plate 7, and an inner peripheral portion of the pressure spring 6 is mounted on a disk 5 shrink-fitted on the output shaft 4. Have been.

The output shaft 4 is rotatably supported by a pair of deep groove ball bearings (rolling bearings) 81, 82 having an outer ring fixed to the base 1 and an inner ring fitted on the outer periphery of the output shaft 4.

The inner ring of the bearing 81 connects the rotor 3 to the stator 2
The disk 5 and the output shaft 4 are bonded to the outer periphery of the output shaft 4 in a state where the disk 5 and the output shaft 4 are pushed toward the stator 2 by the amount of displacement of the pressure spring 6 for bringing the pressure contact into contact with an appropriate force. Further, the compression coil spring 32 is held between the inner ring of the bearing 81 and the inner ring of the bearing 82 in a state of being compressed by a predetermined amount. The amount of compression of the compression coil spring 12 is set to the amount of deformation in which the reaction force component acts on the inner ring of the bearing 82 when the above-described pressure reaction force is proportionally distributed to the ratio between the rated loads of the bearings 81 and 82.

In this embodiment, two bearings 81,
By applying a preload in the same direction in which the pressing reaction force is proportionally distributed to the ratio of the rated load to the bearing 82, the pressing reaction force is applied to the bearings 81 and 82.
As a result, the life of the drive device can be extended.

In this embodiment, since both ends of the compression spring 32 are supported by bearing inner races, and one of the bearing inner races is bonded to the output shaft 4, a groove for fitting a snap ring on the output shaft 4 is machined. Without the cost, it is possible to extend the life at low cost.

(Fourth Embodiment) FIG. 4 shows a fourth embodiment of the present invention.
1 shows a vibration type driving device according to an embodiment. Base 1
Ring-shaped metal stator (vibrator) 2 fixed to
Is connected to an electro-mechanical energy conversion element 22 energized through the connector 10 and the flexible substrate 11 on the lower surface of the elastic body 21, and the friction member 23
It is configured by bonding. The rotor (moving body) 43
The pressure spring 43a and the disk 43b are integrally provided. The disk portion 43b of the rotor 43 is bonded to the output shaft 44 in a state where the output shaft 44 is inserted from below the base 1 and is pushed in by a displacement for obtaining an appropriate pressing force.

The output shaft 44 includes an output shaft 4 having a rolling element that rolls in a track groove 44a formed on the outer periphery of the output shaft 44.
4 is rotatably supported by a pair of bearings (rolling bearings) 81 and 82 integrated with the bearing 4. The outer ring of the bearing 81 is the base 1
, And the outer ring of the bearing 82 is held by the base 1 via the compression spring 42. The outer ring of the bearing 82 is the base 1
Is pressed down by a compression spring 42.

The compression amount of the compression spring 42 is
The reaction force component when the pressure reaction force of a is proportionally distributed to the ratio of the rated loads of the bearings 81 and 82 is set to the amount of deformation acting on the inner ring of the bearing 82.

Also in this embodiment, two bearings 81,
By applying a preload in the same direction in which the pressing reaction force is proportionally distributed to the ratio of the rated load to the bearing 82, the pressing reaction force is applied to the bearings 81 and 82.
As a result, the life of the drive device can be extended.

Further, in this embodiment, the number of parts is small, and the whirling of the output shaft due to the engagement between the bearing having the bearing inner ring and the output shaft is also small. It can be a simple driving device.

[0049]

As described above, according to the present invention, the reaction force of the pressing force for bringing the moving body into pressure contact with the vibrating body is distributed to a plurality of bearings, and this is applied to each bearing. Since the bearing is used as a preload, the size and life of each bearing can be reduced, and a compact and long-life vibration type driving device can be realized.

If the load distribution of each bearing is proportionally distributed to the ratio of the rated load of each bearing or the contact surface pressure between the bearing raceway surface and the rolling element is made equal, further bearing and vibration The life of the mold driving device can be extended.

[Brief description of the drawings]

FIG. 1 is a sectional view of a vibration type driving device according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a vibration type driving device according to a second embodiment of the present invention.

FIG. 3 is a sectional view of a vibration type driving device according to a third embodiment of the present invention.

FIG. 4 is a sectional view of a vibration type driving device according to a third embodiment of the present invention.

FIG. 5 is a schematic view of a bearing section of the first embodiment.

FIG. 6 is a schematic view of a bearing portion of a conventional vibration type driving device.

FIG. 7 is a sectional view of a conventional vibration type driving device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Base 2 Stator 3, 43 Rotor 4, 44 Output shaft 5 Disk 6 Pressure spring 7 Rubber 81, 82 Bearing 9 Snap ring 10 Connector 11 Flexible board 12 Wave washer 32 Compression coil spring 42 Compression spring

Claims (11)

[Claims] A vibration member for exciting vibration, a moving member driven by contacting the vibration member, connecting the moving member to an output shaft, and applying a force to the moving member and the vibration member. In a vibration type driving device having a pressing member to be brought into pressure contact and a plurality of bearing members rotatably supporting the output shaft, the plurality of bearings apply a pressing reaction force by the pressing member via the output shaft. A vibration type driving device characterized in that a member is borne. 2. The vibration type driving device according to claim 1, wherein the pressure reaction force is used as an internal preload of the plurality of bearing members. 3. The vibration type drive according to claim 1, wherein the pressure reaction force is shared between the plurality of bearing members according to a ratio of a rated load of each of the plurality of bearing members. apparatus. 4. The vibration type driving device according to claim 1, wherein the plurality of bearing members are rolling bearings. 5. The pressure reaction force is shared by the plurality of rolling bearings so that the contact surface pressure between the raceway surface of each of the rolling bearings and the rolling element is equal. 5. The vibration type driving device according to 4. 6. The output shaft according to claim 6, wherein each of the inner races of the plurality of rolling bearings and the output shaft are integrally movably connected in a direction in which the pressure reaction force acts on the output shaft. Item 6. The vibration type driving device according to item 4 or 5. 7. The vibration type drive according to claim 4, wherein the plurality of rolling bearings are arranged on both sides of the output shaft in the axial direction with the pressing means interposed therebetween. apparatus. 8. An inner ring of a predetermined rolling bearing among the plurality of rolling bearings and the output shaft are integrally movably connected in a direction in which the pressure reaction force acts on the output shaft. The vibration type driving device according to claim 4 or 5, wherein a spring is provided between an inner ring of a predetermined rolling bearing and an inner ring of another rolling bearing. 9. The apparatus according to claim 8, wherein the displacement of the spring is set so that the respective rolling bearings share the pressing reaction force in accordance with the ratio of the rated loads of the respective rolling bearings. Vibration type driving device. 10. The vibration type driving device according to claim 8, wherein the displacement of the spring is set such that the contact surface pressure between the raceway surface of each of the rolling bearings and the rolling element becomes equal. 11. The rolling element of the plurality of rolling bearings,
The vibration type driving device according to claim 4, wherein the orbiting groove formed on the outer periphery of the output shaft is rolled.