JP4543723B2 - Vibration actuator - Google Patents

Description

  The present invention relates to a vibration actuator that supports a shaft connected to a rotating body via a bearing fixed to a vibrating body that drives the rotating body.

A vibration actuator refers to one that obtains a mechanical output such as rotational motion using vibration generated by applying an AC voltage to a piezoelectric element, an electrostrictive element, etc., and particularly uses vibration in the ultrasonic range. Things are called ultrasonic motors.
For example, Patent Document 1 describes an ultrasonic motor that drives an axis using ultrasonic vibration.
JP 2001-8472 A (1st page, FIG. 1 etc.)

FIG. 4 is a cross-sectional view of a vibration actuator proposed by the inventors of the present invention.
The vibration actuator 10 includes a vibration body 11 and a rotor 15, and the vibration body 11 side is fixed and the rotor 15 side is rotationally driven.

  The vibrating body 11 includes a stator 12 and an electromechanical conversion element (hereinafter referred to as “piezoelectric body”) 13 that is joined to the stator 12 and converts electrical energy into mechanical energy. As the piezoelectric body 13, for example, a piezoelectric element or an electrostrictive element is used. A traveling wave (for example, a traveling wave having 9 wavelengths per round) is generated in the vibrating body 11. In addition, a flexible printed circuit board (FPC) 14 for supplying a driving voltage is connected to the lower surface of the piezoelectric body 13.

  The stator 12 is made of a metal material having a high resonance sharpness, and has a ring shape. The stator 12 has a comb tooth 12a having a groove formed on the opposite surface to which the piezoelectric body 13 is joined. The reason for forming the comb teeth 12a is to amplify the amplitude of the traveling wave on the driving surface by bringing the neutral surface of the traveling wave as close as possible to the piezoelectric body 13 side.

  The piezoelectric body 13 is divided into two phases (A phase and B phase) along the circumferential direction, and in each phase, elements with alternating polarization for each half wavelength are arranged. An interval of ¼ wavelength is provided between the A phase and the B phase.

  The rotor 15 is made of, for example, a light metal such as aluminum, and the sliding surface thereof is subjected to a surface treatment for improving wear resistance.

  The stator 12 has a flange portion 12b formed on the inner periphery thereof, and is attached to the stator mount 16 with this flange portion 12b. A shaft 18 is rotatably attached to the stator mount 16 via a bearing 17. The shaft 18 has a rotor 15 attached to the tip thereof.

  The bearing 17 is a single row deep groove ball bearing, and has, for example, a metal inner ring and outer ring made of bearing steel. The outer ring is inserted into the vibrating body mounting base 16, and the shaft 18 is inserted into the inner ring.

  The pressurizing unit 19 is a unit that pressurizes the rotor 15 against the stator 12, and is provided on the shaft 18. The pressurizing means 19 is disposed in contact with the spring 20 and the bearing 17, a press ring 21 that presses one end of the spring 20, a press ring 22 that presses the other end of the coil spring 20, and a groove formed in the shaft 18. And an E-ring 23 that regulates the position of the pressing ring 22.

  In the vibration actuator 10 described above, the inner ring of the bearing 17 and the outer surface of the shaft 18 slide little by little along the longitudinal direction of the shaft 18 due to the vibration generated by the stator 12 and the pressurization by the pressurizing means 19. To do. For this reason, this contact surface portion is a so-called clearance fit (free fit) with a minute interval.

  However, in such a clearance fit portion, metal wear powder is generated due to friction between metals, which may enter into the bearing 17 and cause damage. Furthermore, if the metal wear powder enters the sliding surface portion between the stator 12 and the rotor 15, the sliding surfaces of the stator 12 and the rotor 15 may be damaged, and the performance of the vibration actuator may be deteriorated.

  Further, at the contact portion between the inner peripheral surface of the inner ring of the bearing 17 and the shaft 18, abnormal noise may occur during operation due to a collision between the metal surfaces. Furthermore, the vibration transmitted from the stator 12 to the rotor 15 is also transmitted to the bearing 17 via the shaft 18, which may damage the inside thereof and shorten the life.

  An object of the present invention is to provide a vibration actuator that maintains performance over a long period of time and reduces abnormal noise.

In order to solve the above-mentioned problem, the invention of claim 1 is directed to a vibrating body, a rotating body that rotates by being in pressure contact with the vibrating body, a shaft that supports the rotating body, and the vibrating body are fixed. A fixed member; a pressure member that pressurizes and contacts the rotating body with the vibrating body; a rolling bearing having an outer ring held by the fixed member and an inner ring that rotates together with the shaft; and an inner ring of the shaft and the rolling bearing. A solid lubricating member that is fixed to the inner ring and is movable in the rotational axis direction with respect to the shaft, and at least a surface having solid lubricity, and the pressure member includes: A first spring receiving portion fixed in the direction of the rotation axis with respect to the shaft; a second spring receiving portion fixed in the direction of the rotation axis with respect to an inner ring of the rolling bearing; and the first spring support. Spring provided between the first spring receiving portion and the second spring receiving portion Has, the second spring receiving portion is a vibration actuator according to claim, that it is formed integrally with the solid lubricant member.

According to a second aspect of the present invention, there is provided a vibrating body, a rotating body that rotates in pressure contact with the vibrating body, a shaft that supports the rotating body, a fixing member to which the vibrating body is fixed, and the rotating body. Fixed to the shaft between a pressure member that makes pressure contact with the vibrating body, a rolling bearing having an outer ring held by the fixed member and an inner ring that rotates together with the shaft, and the shaft and the inner ring of the rolling bearing A solid lubricant member having at least a surface having solid lubricity, wherein the pressurizing member is fixed to the shaft in the rotation axis direction, and the rolling bearing. A second spring receiving portion fixed in the direction of the rotation axis with respect to the inner ring, and a spring provided between the first spring receiving portion and the second spring receiving portion. Can move in the rotational axis direction of the shaft with respect to the solid lubricating member Lying, a vibration actuator according to claim.

According to a third aspect of the present invention, there is provided a vibrating body, a rotating body that rotates in pressure contact with the vibrating body, a shaft that supports the rotating body, a fixing member to which the vibrating body is fixed, and the rotating body. A pressure member that is in pressure contact with the vibrating body; and a rolling bearing having an outer ring held by the fixed member and an inner ring that rotates together with the shaft, and the pressure member is configured to rotate the rotating shaft relative to the shaft. A first spring receiving portion fixed in the direction, a second spring receiving portion fixed in the direction of the rotation axis with respect to the inner ring of the rolling bearing, the first spring receiving portion and the second spring The inner ring is movable in the direction of the axis of rotation of the shaft with respect to the solid lubricating member, and the shaft has a contact surface with the inner ring that is solid lubricated. that it is formed in a solid lubricant member having a gender, and wherein the vibration Actuator It is over data.

According to a fourth aspect of the present invention, in the vibration actuator according to any one of the first to third aspects , the material of the solid lubricating member has an impact buffering property. is there.

A fifth aspect of the present invention is the vibration actuator according to any one of the first to fourth aspects, wherein the solid lubricating member is made of resin.

According to a sixth aspect of the present invention, in the vibration actuator according to the fifth aspect , the resin includes at least one selected from the group consisting of polyacetal, polytetrafluoroethylene, polyamide, polypropylene, and polyethylene. Actuator.

According to a seventh aspect of the present invention, in the vibration actuator according to the second aspect, the shaft is formed such that an outer diameter of a portion corresponding to the rolling bearing is smaller than other portions, and the outer diameter is formed smaller. The vibration actuator is characterized in that the solid lubricating member is formed in a portion.

The invention according to claim 8 is the vibration actuator according to claim 3 , wherein the shaft is made of resin.

The invention according to claim 9 is the vibration actuator according to claim 8 , wherein the resin contains reinforcing fibers.

According to the present invention, the following effects can be obtained.
(1) Since the contact surface where the sliding occurs due to the vibration generated by the vibrating body and the pressurization by the pressurizing means has at least one solid lubricity, the generation of metal wear powder due to wear is prevented. It is possible to prevent damage and deterioration of performance due to the inside of the bearing and the sliding surface portion between the vibrating body and the rotating body.
(2) Since the material having solid lubricity has shock buffering properties, generation of abnormal noise due to collision between the surfaces of the sliding portion is prevented.
(3) Due to the above-described shock-absorbing property, vibration transmitted from the vibrating body to the rotating body can be prevented from being transmitted to the bearing through the shaft, the damage can be prevented, and the life can be ensured.

  An object of the present invention is to provide a vibration actuator that maintains performance over a long period of time and reduces noise, and an inner diameter side of a bearing that rotatably supports a shaft connected to a rotor with respect to a stator. This is solved by providing a resin member having solid lubricity between the outer peripheral surface of the resin.

Hereinafter, the present invention will be described in more detail with reference to the drawings and the like.
FIG. 1 is a cross-sectional view of a first embodiment of a vibration actuator to which the present invention is applied.
In the following embodiments, an ultrasonic motor which is a traveling wave motor using an ultrasonic vibration region will be described as an example of a vibration actuator.
Moreover, in each Example shown below, the part which fulfill | performs the same function as the vibration actuator of FIG. 4 mentioned above attaches | subjects what added the other code | symbol to the same code | symbol or the same code | symbol, and repeated. Description to be omitted is omitted as appropriate.

  An outer ring 17a of a bearing 17 which is a single row deep groove ball bearing, for example, is inserted and fixed to the inner peripheral surface portion of the stator mount 16 of the vibration actuator 10A of the present embodiment. The outer ring 17a is fixed to the stator mount 16 by, for example, press fitting or adhesion.

  On the other hand, between the inner ring 17b of the bearing 17 and the shaft 18, a resin member 30 that is a solid lubricating member formed in a cylindrical shape is provided. The inner ring 17b is held in contact with the resin member 30 on the inner circumferential surface in the radial direction and on the end surface opposite to the rotor 15 in the axial direction. The outer ring 17a and the inner ring 17b are each made of a bearing metal such as high carbon chrome steel or stainless steel.

  A shaft 18 is inserted on the inner diameter side of the resin member 30. The interval between the outer peripheral surface of the shaft 18 and the inner peripheral surface of the resin member 30 is such that the resin member 30 is slidable in the axial direction with respect to the shaft 18 and between the resin member 30 and the shaft 18. It is set taking into consideration that there is no excessive rattling.

The resin member 30 is formed of a resin material having solid lubricity. In this specification, having solid lubricity means obtaining a desired low coefficient of friction only by self-lubricating action without interposing a liquid layer such as lubricating oil or a gas phase between the object to be frictioned. It shall be said to be done.
Further, this resin material also has shock buffering properties. That is, when a part of a member made of such a resin material is vibrated, vibrations in other parts away from the member are reduced.
Specific examples of such a resin material include polyacetal (POM), polytetrafluoroethylene (PTFE), polyamide (PA), polypropylene (PP), and polyethylene (PE).

  Further, the pressurizing means 19A for pressurizing and contacting the rotor 15 with the stator 12 is fixed to the shaft 18 by a coil spring 20 provided substantially concentrically with the shaft 18 and an E ring 23 and is in contact with one end of the coil spring 20. 22. The resin member 30 is formed with a press ring 31 that contacts the other end of the coil spring 20.

As described above, according to the first embodiment, the sliding due to the vibration of the vibrating body 11 and the pressurization by the pressurizing unit 19A is caused between the metal shaft 18 and the resin member 30 having solid lubricity. Therefore, the generation of metal wear powder can be reduced. Therefore, it is possible to prevent metal wear powder from entering the bearing 17 or between the friction surfaces of the rotor 15 and the stator 12, preventing damage to these portions, and maintaining performance over a long period of time.
Furthermore, since the resin member 30 is formed of a material having shock-absorbing properties, it is possible to prevent the generation of abnormal noise in the sliding portion between the resin member 30 and the shaft 18, and the shaft 18 is connected from the rotor 15 to the shaft 18. Thus, the ultrasonic vibration propagating to the bearing 17 can be attenuated, and the life of the bearing 17 can be extended.

FIG. 2 is a sectional view of a vibration actuator according to a second embodiment to which the present invention is applied.
As shown in FIG. 2, in the vibration actuator 10B of the second embodiment, the outer diameter of the intermediate portion of the shaft 18B corresponding to the vicinity of the bearing 17 is partially reduced, and a cylindrical shape is formed on the outer peripheral side of this portion by insert molding. Resin member 30B is formed. The outer diameter of the resin member 30B is made larger than the outer diameter other than the intermediate portion of the shaft 18A.

  The resin member 30B has a simple cylindrical shape having no spring receiving portion, and unlike the resin member 30 of the first embodiment, the resin member 30B does not function as a spring receiving member. Therefore, the pressure member 19B includes a spring receiving member 21B that is separate from the resin member 30B. In the spring receiving member 21B, the resin member 30B is inserted on the inner diameter side, and the end surface on the side not in contact with the spring is in contact with the end surface of the inner ring 17b of the bearing 17.

  As described above, according to the present embodiment, in addition to the effects of the first embodiment, the axial load generated by the pressurizing means is not applied to the resin member 30B, which is advantageous in terms of durability.

FIG. 3 is a sectional view of a vibration actuator according to a third embodiment to which the present invention is applied.
In the vibration actuator 10C according to the third embodiment, the entire shaft 18C is made of resin so that the outer peripheral surface of the shaft 18C is in contact with the inner peripheral surface of the inner ring 17b of the bearing 17; It is comprised similarly to this vibration actuator.

As described above, also in the third embodiment, the same effects as in the first embodiment can be obtained, and further, since the number of parts is reduced, there is an effect that the structure and the assembly can be simplified.
However, in the structural design, material selection, and production of the shaft 18C, it is necessary to give sufficient consideration so that the shaft 18C can obtain a desired strength and accuracy. The material of the shaft 18C may be the same as that of the resin component 30 described above, but, for example, polycarbonate (PC) may be used. Moreover, you may make it mix reinforcing fibers, such as glass fiber, carbon fiber, or a whisker, in this resin material, for example.

(Modification)
The present invention is not limited to the embodiments described above, and various modifications and changes are possible, and these are also within the equivalent scope of the present invention.
(1) In each embodiment, the resin members 30, 30B and the shaft 18C, which are solid lubrication members, are made of resin. For example, the core is formed of a material other than resin such as metal, and the surface thereof is as described above. It may be coated with an appropriate resin. Further, a material other than resin and having solid lubricity may be used. Furthermore, the surface of the desired material may be coated with a material having solid lubricity.
(2) The bearings of the above-described embodiments are single row deep groove ball bearings, but other types of bearings can be used as long as they can bear the desired radial load and the axial load (thrust load) generated by the pressure member. A rolling bearing may be used. For example, an angular ball bearing or a tapered roller bearing may be used. Further, a double row rolling bearing may be used.

It is sectional drawing of Example 1 of the vibration actuator to which this invention is applied. It is sectional drawing of Example 2 of the vibration actuator to which this invention is applied. It is sectional drawing of Example 3 of the vibration actuator to which this invention is applied. It is sectional drawing of an example of the vibration actuator which the inventor of this invention has proposed.

Explanation of symbols

10, 10A, 10B, 10C Vibration actuator 11 Vibration body 12 Stator 12a Comb tooth 12b Flange portion 13 Piezoelectric body 14 FPC
15 Rotor 16 Stator mount 17 Bearing 17a Outer ring 17b Inner ring 18, 18B, 18C Shaft 19, 19A, 19B Pressure member 20 Coil spring 21 Spring receiving member 22 Spring receiving member 23 E-ring 30, 30B Resin member 31 Spring receiving portion

Claims (9)

A vibrating body,
A rotating body that rotates in pressure contact with the vibrating body;
A shaft that supports the rotating body;
A fixing member to which the vibrating body is fixed;
A pressing member that pressurizes and contacts the rotating body with the vibrating body;
A rolling bearing having an outer ring held by the fixing member and an inner ring rotating with the shaft;
Is fixed is provided on the inner ring between the inner ring of the rolling bearing and the shaft, it is movable in its axial direction relative to said axis, and a solid lubricant member at least the surface is provided with a solid lubricant ,
The pressure member is
A first spring receiving portion fixed in the direction of the rotation axis with respect to the shaft;
A second spring receiving portion fixed in the direction of the rotation axis with respect to the inner ring of the rolling bearing;
A spring provided between the first spring receiving portion and the second spring receiving portion;
The second spring receiving portion is formed integrally with the solid lubricating member;
Vibration actuator characterized by A vibrating body,
A rotating body that rotates in pressure contact with the vibrating body;
A shaft that supports the rotating body;
A fixing member to which the vibrating body is fixed;
A pressing member that pressurizes and contacts the rotating body with the vibrating body;
A rolling bearing having an outer ring held by the fixing member and an inner ring rotating with the shaft;
A solid lubricating member provided between the shaft and the inner ring of the rolling bearing and fixed to the shaft, and having at least a surface having solid lubricity;
The pressure member is
A first spring receiving portion fixed in the direction of the rotation axis with respect to the shaft;
A second spring receiving portion fixed in the direction of the rotation axis with respect to the inner ring of the rolling bearing;
A spring provided between the first spring receiving portion and the second spring receiving portion;
The inner ring is movable in the rotational axis direction of the shaft with respect to the solid lubricating member;
Vibration actuator characterized by A vibrating body,
A rotating body that rotates in pressure contact with the vibrating body;
A shaft that supports the rotating body;
A fixing member to which the vibrating body is fixed;
A pressing member that pressurizes and contacts the rotating body with the vibrating body;
A rolling bearing having an outer ring held by the fixing member and an inner ring rotating with the shaft;
The pressure member is
A first spring receiving portion fixed in the direction of the rotation axis with respect to the shaft;
A second spring receiving portion fixed in the direction of the rotation axis with respect to the inner ring of the rolling bearing;
A spring provided between the first spring receiving portion and the second spring receiving portion;
The inner ring is movable in the rotational axis direction of the shaft with respect to the solid lubricating member,
The shaft is formed of a solid lubricating member having a solid lubricating property on a contact surface with the inner ring;
Vibration actuator characterized by In the vibration actuator according to any one of claims 1 to 3 ,
The solid lubricating member has a shock-absorbing material;
Vibration actuator characterized by In the vibration actuator according to any one of claims 1 to 4 ,
The solid lubricating member is made of resin.
Vibration actuator characterized by The vibration actuator according to claim 5 , wherein
The resin has at least one selected from the group consisting of polyacetal, polytetrafluoroethylene, polyamide, polypropylene, and polyethylene;
Vibration actuator characterized by The vibration actuator according to claim 2 ,
The shaft is formed such that the outer diameter of the portion corresponding to the rolling bearing is smaller than that of the other portion, and the solid lubricating member is formed in a portion where the outer diameter is smaller,
Vibration actuator characterized by The vibration actuator according to claim 3 , wherein
The shaft is made of resin.
Vibration actuator characterized by The vibration actuator according to claim 8 , wherein
The resin contains reinforcing fibers;
Vibration actuator characterized by

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