JP4835042B2 - Vibration wave motor - Google Patents

Description

  The present invention relates to a vibration wave motor that generates vibration waves in a vibrator using an electromechanical transducer and frictionally drives a relative motion member using the vibration waves.

Conventionally, this type of vibration wave motor has a problem that abnormal noise is generated due to vibration of other members such as a relative motion member due to vibration of a vibrator during driving.
In order to reduce this abnormal noise, Patent Document 1 discloses an example in which an abnormal noise is reduced by using a rubber vibration-proof member as a part of the moving body. However, there are many types of rubber, and if selected incorrectly, there is a problem that abnormal noise is caused.

For example, Patent Document 2 describes a vibration actuator in which a rubber material formed of butyl rubber is provided between a moving body and a driven body. However, the physical properties of butyl rubber are likely to change due to changes in temperature, and there is a problem that vibration absorption capacity declines and abnormal noise is generated particularly in a low temperature environment.
JP-A-61-224884 JP 2001-57787 A

  An object of the present invention is to provide a vibration wave motor that always generates less abnormal noise regardless of the use environment.

In order to solve the above-mentioned problem, the invention according to claim 1 is directed to a vibrator that generates vibration by excitation of an electromechanical transducer and a pressure contact between the vibrator and the vibrator by the vibration. A vibration wave motor comprising: a relative motion member that performs relative motion at a pressure; a pressure unit that pressurizes and contacts the vibrator and the relative motion member; and a relative motion member-side support member that supports the relative motion member. The noise reduction member formed of ethylene-propylene rubber at a position sandwiched between the relative motion member and the relative motion member side support member in the direction in which the pressurizing unit pressurizes the noise reduction member. Is a vibration wave motor characterized by having a Shore hardness of 50 or less .
According to a second aspect of the present invention, there is provided a vibrator that generates vibration by excitation of an electromechanical transducer, and a relative motion member that is in pressure contact with the vibrator and performs relative motion between the vibrator and the vibrator. A vibration wave motor comprising: a pressurizing unit that pressurizes and contacts the vibrator and the relative motion member; and a vibrator-side support member that supports the vibrator. A noise reducing member formed of ethylene-propylene rubber at a position sandwiched between the vibrator and the vibrator-side support member, and the noise reducing member has a Shore hardness of 50 or less. This is a characteristic vibration wave motor.
The invention according to claim 3 is the vibration wave motor according to claim 1 or 2, wherein the ethylene-propylene rubber is EPDM.
According to a fourth aspect of the present invention, in the vibration wave motor according to any one of the first to third aspects, the noise reduction member divides a surface pressure applied to the noise reduction member by a compression elastic modulus. The vibration wave motor is characterized in that the compression ratio is 0.002 or more and 0.25 or less.
According to a fifth aspect of the present invention, in the vibration wave motor according to any one of the first to fourth aspects, the pressurizing unit pressurizes between the relative motion member and the pressurizing unit. The vibration wave motor is characterized in that the vibrator is located in the position.
The invention according to claim 6 is the vibration wave motor according to any one of claims 1 to 5 , wherein the output shaft that rotates integrally with the relative motion member while supporting the relative motion member; And a flange portion provided at one end of the output shaft, wherein the noise reduction member is sandwiched between the flange portion and the relative motion member.
According to a seventh aspect of the present invention, in the vibration wave motor according to the sixth aspect , the vibration wave motor includes a fixing member that supports the vibrator, and the fixing member is rotatably positioned with respect to the output shaft via one bearing. This is a vibration wave motor.
According to an eighth aspect of the present invention, in the vibration wave motor according to the seventh aspect , the bearing is positioned between the vibrator and the pressurizing unit in a direction in which the pressurizing unit pressurizes. It is a vibration wave motor.

According to the present invention, the following effects can be obtained.
Strange noise reducing member is an ethylene - formed by propylene rubber, since the pressure portion is provided at a position sandwiched between the relative moving member and the relative movement member supporting member in the direction for pressurizing, the relative moving member and the relative movement member side Abnormal noise transmitted to the support member or the like can be absorbed to reduce the occurrence of abnormal noise. In addition, ethylene-propylene rubber has higher aging resistance, cold resistance, and the like than butyl rubber and the like, and thus is effective in reducing abnormal noise even when used in a low temperature environment where abnormal noise is likely to occur.

  The object of the present invention is to provide a vibration wave motor that always generates less abnormal noise regardless of the usage environment, and has a shore hardness of 50 or less and a compression obtained by dividing the surface pressure applied when the vibration wave motor is driven by the compression modulus. The noise reduction member formed by EPDM having a rate of 0.002 to 0.25 is provided between the relative motion member and the relative motion member-side support member that supports the relative motion member.

Hereinafter, Example 1 of the present invention will be described in detail with reference to the accompanying drawings. In the following embodiments, an ultrasonic motor using an ultrasonic vibration region will be described as an example of a vibration wave motor.
FIG. 1 is a cross-sectional view schematically showing a first embodiment of a vibration wave motor according to the present invention.
The ultrasonic motor 10 includes a vibrator 11, a moving body 14, an abnormal noise reducing member 15, supports 16A and 16B, a pressure unit 18, and the like.

The vibrator 11 is a substantially ring-shaped member, and includes an elastic body 12 and a piezoelectric body 13.
The piezoelectric body 13 is an electromechanical transducer such as a piezoelectric element or an electrostrictive element that converts electrical energy into mechanical energy, and is joined to an elastic body 12 described later. The piezoelectric body 13 is excited by a drive signal supplied from a flexible printed board (not shown) that is electrically connected to the predetermined electrode portion.
The elastic body 12 is a substantially annular member formed of an iron alloy such as a stainless material or an invar material, and a piezoelectric body 13 is bonded to one surface of the elastic body 12 with a conductive adhesive or the like. On this surface, a comb tooth portion formed by cutting a plurality of grooves is provided. The tip surface of the comb tooth portion is a drive surface that pressurizes and contacts the moving body 14 to be described later and drives the moving body 14.
A progressive vibration wave (hereinafter referred to as a traveling wave) is generated in the elastic body 12 by the excitation of the piezoelectric body 13.
The moving body 14 has a substantially annular shape, and is a relative motion member that is pressed against the elastic body 12 by a pressurizing unit 18 described later and is frictionally driven by a traveling wave generated on the driving surface of the elastic body 12.

The noise reduction member 15 is a substantially ring-shaped member formed by EPDM (Ethylene-Propylene-Diene Methylene Linkage), which is a kind of ethylene-propylene rubber, and is in a direction in which a pressurizing unit 18 to be described later pressurizes. It is provided at a position sandwiched between the moving body 14 and the support 16A.
The support body 16 </ b> A is a relative motion member-side support member that supports the moving body 14. The support body 16A and the moving body 14 are engaged by an engaging portion (not shown) so that the support body 16A and the moving body 14 rotate together, and the rotational movement of the moving body 14 is not allowed. It is a member which transmits to the driven member of illustration.

The pressurizing unit 18 is a portion that pressurizes the vibrator 11 and the moving body 14 and includes a pressurizing plate 18a, a disc spring 18b, and the like. The pressure plate 18a is a plate that receives the applied pressure generated by the disc spring 18b.
The buffer member 17 is formed of a non-woven fabric or felt, and is a member that prevents the vibration of the vibrator 11 from being transmitted to the pressurizing unit 18, and is provided between the piezoelectric body 13 and the pressurizing plate 18a.
The support 16B is a vibrator-side support member that fixes the ultrasonic motor 10 to, for example, a lens barrel of a camera.

Next, the noise reduction member 15 of the ultrasonic motor 10 of this embodiment will be described in more detail.
The elastic body 12 is made of stainless steel (SUS304). The elastic body 12 has a piezoelectric body 13 bonded to an opposite surface of the driving surface with an epoxy adhesive.
On the other hand, the moving body 14 is made of an Al alloy (A6063), and an oxide film such as alumite is formed on the surface by performing anodizing treatment or the like.
The noise reduction member 15 is formed by punching a sheet-like member formed by EPDM, and the surface thereof is a glossy surface. In this embodiment, the Shore hardness of the noise reduction member 15 is 50 or less, and the compression rate (hereinafter referred to as compression rate) obtained by dividing the surface pressure applied to the noise reduction member 15 by the compression elastic modulus is 0.002. It is set to be 0.25 or less.

  Here, in order to evaluate the effect of noise reduction according to the present embodiment, the noise reduction member 15 having substantially the same shape as the noise reduction member 15 of the present embodiment and having a different material, shore hardness, compressibility, etc. A plurality of samples were prepared, and were actually driven using an ultrasonic motor similar to the ultrasonic motor 10, and the occurrence of abnormal noise during the driving was measured.

(Relationship between Shore hardness and abnormal noise)
FIG. 2 is a table showing measurement results regarding the Shore hardness and the occurrence of abnormal noise.
Samples 1 to 8 of the noise reducing member used for this measurement are all substantially ring-shaped and have a thickness of 0.5 mm. Samples 1 to 6 are formed of EPDM and have a Shore hardness of 10, 20, 30, 40, 50, 60. Samples 7 and 8 are formed of IIR (butyl rubber) and have a Shore hardness of 40, 60. It is. The surface pressure applied to each sample when the ultrasonic motor is driven is 0.4 MPa, which is constant.
As shown in FIG. 2, the abnormal noise reducing members 1 to 5 of the abnormal noise reduction member formed by EPDM and having a Shore hardness of 50 or less did not generate abnormal noise in all temperature environments.
However, sample 6 of the noise reduction member formed by EPDM and having a Shore hardness of 60 or more is different from samples 7 and 8 of the noise reduction member formed by IIR and having a Shore hardness of 40 to 60 in a low temperature environment. Sound generation was confirmed.
As a result, the noise reduction member 15 is formed of EPDM as shown in the present embodiment, and its Shore hardness is 50 or less, which is required when noise reduction is required even in a low temperature environment. It is valid.

(Relationship between compression rate and abnormal noise)
FIG. 3 is a table showing measurement results regarding the compression rate and the occurrence of abnormal noise.
The sample of the noise reduction member used for this measurement is formed by EPDM, and its Shore hardness is 40, and the 10% compression elastic modulus is 3.0 MPa. The measurement was performed at room temperature, and the compression rate was changed by changing the pressure applied by the disc spring 18b.
From the measurement results shown in FIG. 3, the noise reduction member is effective in reducing noise if the compression ratio is 0.002 or more and 0.25 or less.

From the results shown in FIG. 2 and FIG. 3, the noise reduction member 15 is formed of EPDM, has a Shore hardness of 50 or less, and a compression rate of 0.002 or more and 0.25 or less, depending on the use environment. This is effective in reducing abnormal noise.
Moreover, since the loss of energy due to the generation of abnormal noise is reduced, the driving efficiency of the ultrasonic motor 10 can be improved.
Furthermore, since EPDM is lightweight, the product can be reduced in weight.
Here, when the abnormal noise reducing member 15 having a Shore hardness of 40 and a compression ratio of 0.1 is actually driven using the ultrasonic motor 10, even in a low temperature environment where abnormal noise is likely to occur, Abnormal noise was not generated, and an advantageous effect was obtained compared with the conventional vibration wave motor.

FIG. 4 is a sectional view schematically showing Embodiment 2 of the ultrasonic motor according to the present invention.
The ultrasonic motor 20 according to the second embodiment includes a vibrator 21, a moving body 25, a fixed member 26, a bearing 27, an output shaft 28, a pressure unit 29, and the like.
The vibrator 21 is a substantially annular member having an elastic body 22, a piezoelectric body 23 bonded to the elastic body 22, and the like. A traveling wave is generated in the vibrator 21 by the expansion and contraction of the piezoelectric body 23.

The elastic body 22 is formed of a metal having a high resonance sharpness, such as a stainless material, and has a substantially annular shape, and has a comb tooth portion 22a in which a plurality of comb teeth are formed in the circumferential direction, and is continuous in the circumferential direction. The base portion 22b is formed. The front end surface of the comb-tooth portion 22a is a drive surface that is brought into pressure contact with the moving body 25 described later.
The elastic body 22 is provided with a flange portion 22c on the inner peripheral side of the base portion 22b, and is supported and fixed to the fixing member 26 by the flange portion 22c.

The piezoelectric body 23 is an electromechanical conversion element such as a piezoelectric element or an electrostrictive element that converts electrical energy into mechanical energy. The piezoelectric body 23 has a range in which electric signals of two phases (A phase and B phase) are input along the circumferential direction. In the range corresponding to each phase, the piezoelectric body 23 is polarized every ½ wavelength. Are arranged in such a way that an interval of ¼ wavelength is provided between the A phase and the B phase.
The piezoelectric body 23 is connected to the wiring of the flexible printed circuit board 23 a to the electrodes of each phase, and expands and contracts by a drive signal supplied from the outside to the flexible printed circuit board 23 a to cause the elastic body 22 to vibrate.

  The moving body 24 is a member that is in pressure contact with the drive surface of the elastic body 22 and is rotationally driven by an elliptical motion caused by a traveling wave generated on the drive surface, and is fitted to the output shaft 18. The moving body 24 is made of a light metal such as aluminum.

The output shaft 28 has a substantially cylindrical shape, has a substantially disk-shaped flange portion 28 a at one end thereof, and is rotatably attached to the fixed member 26 via a bearing 27. The output shaft 28 and the moving body 24 are fitted in a so-called D-cut shape, and the output shaft 28 rotates integrally with the moving body 24 to rotate the moving body 24 to a driven member (not shown). introduce.
Further, the output shaft 28 is configured such that a pressurizing unit 29 described later regulates the position of the moving body 24 in a direction in which the moving body 24 and the vibrator 21 are pressed, and also supports the moving body 24. It functions as a support member.

  The noise reduction member 25 is a substantially ring-shaped member, and is provided at a position sandwiched between the flange portion 28a of the output shaft 28 and the moving body 24 in a direction in which a pressurizing portion 29 described later pressurizes. This noise reduction member 25 is formed by stamping a sheet-like member formed of EPDM, similar to the noise reduction member 15 shown in Example 1, and its surface is a glossy surface. Its thickness is 0.5 mm. The noise reduction member 25 is set so that the Shore hardness is 50 or less and the compression rate is 0.002 or more and 0.25 or less.

  The pressurizing unit 29 is a mechanism that pressurizes the vibrator 21 and the moving body 24, and is provided on the output shaft 28. The pressurizing unit 29 is disposed in contact with the spring 29a that generates a pressing force, the bearing 27, a press ring 29b that presses one end of the spring 29a, a press ring 29c that presses the other end of the spring 29a, and an output shaft 28. And an E-ring 29d for restricting the position of the pressing ring 29c.

By using the noise reduction member 25 of the present embodiment for the ultrasonic motor 20, it is possible to reduce the occurrence of noise and improve the drive efficiency of the ultrasonic motor 20, as in the first embodiment.
As mentioned above, according to the said Example, there can exist the following effects.
(1) The noise reduction members 15 and 25 are made of ethylene-propylene rubber, and the moving members 14 and 24 and the support member 16A or the output shaft 28 on the relative motion member side in the direction in which the pressurizing portions 18 and 29 pressurize. Therefore, it is possible to reduce the generation of abnormal noise by absorbing unnecessary vibration transmitted to the movable bodies 14 and 24, the support 16A on the relative motion member side, the output shaft 28, and the like. In addition, ethylene-propylene rubber has higher aging resistance, cold resistance, and the like than butyl rubber and the like, and thus is effective in reducing abnormal noise even when used in a low temperature environment where abnormal noise is likely to occur.
(2) Since ethylene-propylene rubber is EPDM, its physical properties are unlikely to change even in a low temperature environment where abnormal noise is likely to occur, and the vibration absorption capability does not decrease, which is effective in reducing abnormal noise. Moreover, since EPDM is lightweight, it can also be expected to reduce the weight of the product.
(3) Since the noise reduction members 15 and 25 have a Shore hardness of 50 or less, they can absorb unnecessary vibration and are effective in reducing the noise.
(4) Since the compression ratio obtained by dividing the surface pressure applied to the noise reduction members 15 and 25 by the compression elastic modulus is 0.002 or more and 0.25 or less, the abnormal noise reduction members 15 and 25 cause unnecessary vibration. It can absorb and is effective in reducing abnormal noise.

(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 Example 1, although the abnormal noise reduction member 15 showed the example provided in the position pinched | interposed into the moving body 14 and the support body 16A in the direction which the pressurization part 18 pressurizes, it is not restricted to this, For example, you may provide in the position (position of the buffer member 17) pinched by the vibrator | oscillator 11 and the support body 16B in the direction which the pressurization part 18 pressurizes.
Further, it is provided at both the position sandwiched between the moving body 14 and the support 16A in the direction in which the pressurizing unit 18 presses and the position sandwiched between the vibrator 11 and the support 16B in the direction in which the pressurizing unit 18 pressurizes. May be.
The noise reduction member is formed of ethylene-propylene rubber and is provided at a position sandwiched between the vibrator 11 and the support 16B on the vibrator side in the direction in which the pressurizing unit 18 applies pressure, and thus absorbs unnecessary vibration. Thus, the vibrator-side support 16B and the like can be prevented from vibrating and the occurrence of abnormal noise can be reduced. In addition, ethylene-propylene rubber has higher aging resistance, cold resistance, and the like than butyl rubber and the like, and thus is effective in reducing abnormal noise even when used in a low temperature environment where abnormal noise is likely to occur.

(2) In the second embodiment, the example in which the noise reduction member 25 is provided between the moving body 24 and the output shaft 28 is shown, but the present invention is not limited to this. For example, the fixing member 26 and the vibrator 21 ( You may provide between flexible printed circuit boards 23a).

(3) In each embodiment, the noise reduction members 15 and 25 are formed by punching, and the surface thereof is a glossy surface. It may be formed by a method. Further, the surface state of the noise reduction members 15 and 25 may be matte finish and is not particularly limited.

(4) In each embodiment, the example in which the noise reduction members 15 and 25 are formed of a single EPDM has been shown. However, the present invention is not limited to this, and for example, EPDM may be used by bonding a film, an adhesive, or the like. Good.

(5) In each embodiment, the noise reduction members 15 and 25 are applied to the rotary ultrasonic motors 10 and 20, but the present invention is not limited to this. You may apply.

(6) In each Example, although the noise reduction members 15 and 25 showed the example applied to the ultrasonic motors 10 and 20 which drive the mobile bodies 14 and 24 by a progressive vibration wave, it did not restrict to this. For example, the present invention may be applied to a vibration wave motor that drives a moving body by vibration of a torsional vibrator.

(7) In each of the embodiments, the example in which the noise reduction members 15 and 25 are applied to the ultrasonic motors 10 and 20 has been described. You may apply.

It is sectional drawing which shows typically Example 1 of the ultrasonic motor by this invention. It is a table | surface which shows the measurement result regarding generation | occurrence | production of Shore hardness and abnormal noise. It is a table | surface which shows the measurement result regarding compression rate and generation | occurrence | production of abnormal noise. It is sectional drawing which shows typically Example 2 of the ultrasonic motor by this invention.

Explanation of symbols

10, 20: Ultrasonic motor, 11, 21: Vibrator, 12, 22: Elastic body, 13, 23: Piezoelectric body, 14, 24: Mover, 15, 25: Noise reduction member, 16A, 16B: Support Body, 17: buffer member, 18, 29: pressurizing part, 28: output shaft

Claims (8)

A vibrator that generates vibration by excitation of an electromechanical transducer;
A relative motion member that is in pressure contact with the vibrator and performs relative motion with the vibrator by the vibration;
A pressurizing unit that pressurizes and contacts the vibrator and the relative motion member;
A relative motion member-side support member that supports the relative motion member;
In the vibration wave motor with
In a position sandwiched between the relative motion member and the relative motion member side support member in a direction in which the pressurizing unit pressurizes, an abnormal noise reducing member formed of ethylene-propylene rubber is provided ,
The abnormal noise reducing member has a Shore hardness of 50 or less,
Vibration wave motor characterized by A vibrator that generates vibration by excitation of an electromechanical transducer;
A relative motion member that is in pressure contact with the vibrator and performs relative motion with the vibrator by the vibration;
A pressurizing unit that pressurizes and contacts the vibrator and the relative motion member;
A vibrator-side support member that supports the vibrator;
In the vibration wave motor with
An abnormal noise reducing member formed of ethylene-propylene rubber is provided at a position sandwiched between the vibrator and the vibrator side support member in a direction in which the pressurizing unit pressurizes ,
The abnormal noise reducing member has a Shore hardness of 50 or less,
Vibration wave motor characterized by In the vibration wave motor according to claim 1 or 2,
The ethylene-propylene rubber is EPDM;
Vibration wave motor characterized by In the vibration wave motor according to any one of claims 1 to 3 ,
The noise reduction member has a compression ratio of 0.002 or more and 0.25 or less obtained by dividing the surface pressure applied to the noise reduction member by the compression elastic modulus.
Vibration wave motor characterized by In the vibration wave motor according to any one of claims 1 to 4 ,
The vibration wave motor, wherein the vibrator is positioned between the relative motion member and the pressurizing unit in a direction in which the pressurizing unit pressurizes. In the vibration wave motor according to any one of claims 1 to 5 ,
An output shaft that rotates integrally with the relative motion member while supporting the relative motion member;
A flange portion provided at one end of the output shaft,
The vibration wave motor, wherein the noise reduction member is sandwiched between the flange portion and the relative motion member. The vibration wave motor according to claim 6 ,
A fixing member for supporting the vibrator;
The fixed wave member is positioned so as to be rotatable with respect to the output shaft through one bearing. In the vibration wave motor according to claim 7 ,
The vibration wave motor, wherein the bearing is positioned between the vibrator and the pressurizing unit in a direction in which the pressurizing unit pressurizes.

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