JP2010057362A - Vibration wave driver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vibration wave driver that drives stably, even if an external force is applied to an output shaft from various directions. <P>SOLUTION: The vibration wave driver is provided with a case, including a vibrating body and a rotating body, the case supporting the vibrating body with a vibrating body supporting member; a plurality of bearings provided in the case that support an output shaft; a means for deciding a position of the output shaft in relation to the case, and for sandwiching the bearings from both sides; and a bearing that supports the output shaft, the bearing being provided in a through-hole formed in the vibrating body and being provided in contact with the output shaft. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a vibration wave driving device having an output shaft.

Conventionally, several vibration motors (vibration wave driving devices) having an output shaft are known. For example, as shown in FIG. 4, there is a motor disclosed in Patent Document 1 . In this motor, piezoelectric elements 142 and 144 are arranged between a metal block 150 and a metal block 152 as a hollow cylindrical elastic body, and cylindrical coupling bolts arranged on the inner peripheral side of these metal blocks 150 and 152. A combination of the metal blocks 150 and 152 by 154 is used as the vibrating body 140. On the other hand, in the motor housing (outer case), the cylinder portion at the center of the motor forms a motor support portion, and a bearing 172 is disposed on the motor support portion to support the output shaft 134, and the coupling bolt 154 A ring-shaped brim portion 175 provided on the inner diameter portion is fixed and supports the vibrating body 140. In addition, a rotor part 130 as a contact body is disposed on one side of the vibrating body 140, and the rotor part 130 includes a rotor body (disk) 132 fixed to the output shaft 134 in the rotation direction, a support plate 136, and the like. In this configuration, the rotor 133 is placed in pressure contact with the end face of the metal block 152 by the spring force of the spring 133.

Japanese Patent Laid-Open No. 5-38170

  However, in the conventional example, since there is one bearing, when a force from a side surface is applied to the output shaft, the output shaft is tilted with the bearing as a fulcrum, and the rotor portion is displaced from the vibrating body. As a result, the frictional contact state at the rotor contact surface 160 where the rotor body 132 is in contact with the metal block 152 becomes non-uniform, resulting in problems such as reduced motor efficiency, squealing, and contact surface wear (reduced motor life). .

  An object of the invention according to the present application is to provide a vibration wave driving device that can be stably driven even when an external force acts on the output shaft from various directions.

Configuration for realizing the object of the invention according to this application, electrical - a vibration body to form a circular or elliptic motion by combining the mechanical energy conversion element and the vibrating body support member is fixed to the elastic member two bending vibrations, the a rotary body rotating by pressure contact with the circular or elliptical motion to the vibrating body, the vibrating body and having a, an output shaft passing through the through hole provided in the rotating body, the output shaft is the rotator In the vibration wave drive device that rotates integrally with the case, the vibration body and the rotation body are built in, the case supports the vibration body via the vibration body support member, the case is provided with the output shaft Yes a plurality of bearings for supporting, scissors the bearing from both sides, and means for determining the position relative to the casing of said output shaft, provided in the through-hole of the vibrating body, a bearing for rotatably supporting said output shaft, a characterized in that it

  With the above configuration, even when a force from the side acts on the output shaft, such as when a gear is attached to the output shaft and the output is taken out to the outside, the rotating body does not shift or tilt. Therefore, the vibration of the vibrating body is stably transmitted to the rotating body, and the motor has excellent performance.

  Since the bearing and the output shaft are all loosely fitted (gap fit, the output shaft can rotate with respect to the bearing), the vibrating body does not tilt with respect to the output shaft.

  Furthermore, if at least one of the surface members that contact each other is formed of resin at the part where the bearing and the output shaft are loosely fitted, the vibration of the vibrating body is transmitted to the output shaft, as in the case of metal. Is likely to cause noise, but this is not the case.

  In general, it is necessary to avoid applying lubricating oil to the loosely fitting portion. This is because when the lubricating oil moves to the friction contact surface, the torque of the motor is remarkably reduced. It is desirable to use oil-impregnated metal or oil-impregnated resin to reduce the friction loss and wear of the bearing.

As described above, according to the present invention, since the positional relationship of the output shaft with respect to the through hole and the case of the vibrating body is determined, even if force is applied to the output shaft from various directions , the contact of the friction sliding surface Since the state is stable, the vibration wave drive device has high efficiency and long life.

  In addition, by providing a bearing in the through hole of the rotating body, when the rotating body rotates, the eccentricity with respect to the vibrating body axis decreases, so that the motor is more excellent. Furthermore, the occurrence of noise was suppressed by using a resin for the bearing surface of the slide bearing or the surface of the output shaft that is supported by the bearing surface.

Sectional drawing which shows 1st Embodiment. Sectional drawing which shows 2nd Embodiment. Sectional drawing which shows 3rd Embodiment. Sectional drawing of the conventional vibration motor.

(First embodiment)
FIG. 1 shows a first embodiment of the present invention.

  The vibration wave driving device according to the present embodiment includes a ring-shaped piezoelectric element 4 as an electromechanical energy conversion element and a vibrating body support member 3 formed of a thin plate of metal or the like, and a rod-like hollow as two elastic bodies. The vibrating members are configured by sandwiching the metal members 5 and 6 between the metal hollow bolts 1 and nuts 7 serving as fastening members.

The vibrating body according to the present embodiment combines two bending vibrations to form a circular or elliptical motion on the driving surface. The driving principle is described in Japanese Patent Laid-Open No. 3-011981 and the like. Since there is, explanation is omitted .

  In the vibration wave driving device according to the present embodiment, a rotating body 8 is disposed on one side of the vibrating body, and a cylindrical sliding member 8a is fixed to the outer peripheral portion of the rotating body 8. The tip of the sliding member 8a comes into contact with the friction sliding member 5a on the vibrating body side provided at the outer peripheral end of the end surface of the metal member 5 constituting the vibrating body. The rotating body 8 is fitted to the outer diameter portion of the pressure spring 9 of a disc spring whose coaxiality and inclination with the output shaft 2 are regulated by the caulking member 12. The sliding member 8a and the friction sliding member 5a on the vibrating body side are brought into pressure contact.

  The vibrating body of the present embodiment is configured by sandwiching and fixing the vibrating body support member 3 simultaneously with the piezoelectric element 4. The vibrating body support member has a disk shape, and its outer peripheral portion is joined to the butted surfaces of the case portions 15 and 16 of the outer two-divided case. This joining is performed by electric resistance welding, laser welding, bonding with an adhesive or brazing.

  The role of the vibrating body support member 3 is to support the vibrating body. However, if the vibrating body support member is too thick and too rigid, vibration generated in the vibrating body is transmitted to the case, and the efficiency is improved. High vibration energy is not generated. Therefore, the vibrating body support member 3 has appropriate flexibility. As a result, the spatial position of the vibrating body is not firmly determined with respect to the outer case, and is inclined or eccentric.

As a result, the vibration of the vibrating body is not efficiently transmitted to the frictional sliding member 8a of the rotating body 8, resulting in the following problems.
1. 1. Generation of motor noise 2. Friction sliding member wears unevenly and motor life decreases. Reduction of motor efficiency In order to prevent these problems, in the present embodiment, the through hole 1a of the hollow bolt 1 serves as a bearing that supports the output shaft 2.

  In the present embodiment, a sintered metal oil-impregnated bearing 11 is caulked in one outer case portion 15, and the ball bearing bearing 10 is press-fitted in the other outer case 16 on the opposite side. The output shaft 2 is pivotally supported by these two bearings 10 and 11.

  Further, since the two retaining rings 17 are arranged so as to sandwich the ball bearing 10 from both sides, the spatial position of the output shaft 2 is determined with respect to the outer case. That is, the position of the output shaft 2 is first determined with respect to the outer case, and the through hole 1a acts as a bearing with respect to the output shaft 2, so that the position of the vibrating body is determined.

  On the other hand, the rotating body 8 is fitted to the outer diameter portion of the pressure spring 9 whose coaxiality and inclination with the output shaft 2 are regulated by the caulking member 12. Accordingly, the rotational position of the rotating body 8 can be determined with respect to the output shaft 2.

  As described above, since the position of the vibrating body and the rotating body 8 is determined based on the output shaft 2, the rotating body-side frictional sliding member 8a and the vibrating body-side frictional sliding member 5a can stably contact each other. became.

  In the present embodiment, the vibration isolating rubber 23 is interposed between the rotating body 8 and the pressure spring 9, thereby preventing the vibration of the rotating body 8 from propagating to the output shaft 2. Also, the rotating body 8 and the pressure spring 9 are joined.

  In the vicinity of the ball bearing 10, a rotating plate 13 that is an encoder component for detecting the rotational position is fixed to the output shaft 2. A number of holes are formed in the rotating plate 13 in the radial direction, and the position is detected by counting the rotation by blocking and passing light from the photo interrupter 14 fixed inside the case 16. . The photo interrupter 14 is more desirable because it can improve the resolution and increase the positioning accuracy if a fiber type thin light beam can be obtained. Although a light detection type sensor is used in the present embodiment, a potentiometer or the like that detects a rotational position by a change in electric resistance value may be incorporated in the case.

(Second Embodiment)
FIG. 2 shows a second embodiment of the present invention.

  Unlike the first embodiment, the vibrating body of the present embodiment does not use a hollow bolt that is a fastening member. The metal members 5 and 6 as two elastic members, the vibrating body support member 3 and the piezoelectric element 4 are bonded and bonded by an adhesive.

  In the present embodiment, the friction sliding portions are provided at both ends of the vibrating body, and two rotating bodies 8 are also provided. As a result, the generated torque is usually doubled compared to a motor with a single rotating body. In addition, a large-diameter hole is formed in the shaft center of the rotating body 8 from the outer end side, and the inner end side is set to a small diameter so that the pressurizing coil spring 9 does not fall out into the large-diameter hole. Has been placed.

  Further, a rotation stopper 12 is attached to the large-diameter hole on the outer end side of each rotating body 8, and a spline is cut on the outer periphery of the rotation stopper 12, so that the rotating body 8 is fitted. Yes. The rotation stopper 12 is inserted into the inner spline portion of the rotating body 8 while being pressed into the output shaft 2 and compressing the pressure spring 9. The rotating body 8 is restrained from rotating with respect to the rotation stopper 12, but can freely slide in the axial direction. Therefore, only the rotational force of the rotating body 8 can be transmitted to the output shaft 2.

  At the inner diameter ends of the elastic members 5 and 6, a slide bearing type slide bearing 18 with a flange is provided. In the present embodiment, the bearing portion of the slide bearing 18 is made of polyacetal, but depending on the operating temperature of the motor, it is better to have a high heat-resistant temperature such as nylon, Teflon (registered trademark), PPS or the like. In some cases.

  In the present embodiment, the slide bearing 18 is fixed to the outside of the metal members 5 and 6 as elastic members, and the output shaft 2 rotates relative to the slide bearing 18, but the output shaft 2 and the slide bearing 18 are fixed. The slide bearing 18 and the metal members 5 and 6 may be rotatable. In this case, the output shaft 2 may be covered with a heat shrinkable tube made of resin, or the output shaft 2 may be coated with a resin such as Teflon (registered trademark). Further, it is desirable that oil is contained in the resin because the output shaft 2 can rotate more smoothly.

  Since this oil does not flow out to the outside, there is no fear of oil sneaking around the frictional sliding part of the vibrating body or the rotating body. Further, the sliding bearing 18 may be arranged at a position that becomes a vibration node of the vibrating body so that vibration leakage is small. The slide bearing 18 may be made of oil-impregnated sintered metal, but a resin is preferable because noise is easily generated due to vibration of the vibrating body.

  The vibrating body and the rotating body are press-fitted with the rotation stopper 12 into the output shaft 2, assembled in advance outside the case, and inserted into the outer case 30 formed by a press drawing.

  Since the vibrating body support plate 3 has three legs extending radially outward and the distal end is bent as shown in FIG. 2, the insertion into the outer case 30 can be performed smoothly. When the rotation stopper 12 hits the slide bearing type slide bearing 11, the vibrating body is rotated with respect to the outer case around the output shaft, and the vibrating body support member 3 is inserted into the three holes 30 a provided in the outer case 30. Fit the three legs using their elastic restoring force.

  The number of legs of the vibrating body support member is not limited to three, and may be one. The role of the support member is to resist torsional force applied to the vibrating body without transmitting the vibration of the vibrating body to the case. Since the displacement near the center of the vibrating body is minute and substantially perpendicular to the output shaft, the support member is designed to be soft in this direction and stiff in the torsional direction of the vibrating body.

  Then, the lid 31 is fitted into the outer case 30, and at this time, the resin spacer 19 is put into the output shaft 2. Even when an axial force is applied to the output shaft 2 by the spacer 19, an excessive force is not applied to the vibrating body support member 3 and the like.

  Finally, the vibrating body support member 3 was soldered to the hole 30a of the outer case 30, and the outer case 30 and the lid body 31 were joined with an adhesive. In these cases, of course, welding may be used. In the present embodiment, the rotating body 8 is pressed against the vibrating body side frictional sliding member 5a by the pressurizing spring 9, but the reaction force is received by the two rotation stoppers 12 press-fitted into the output shaft 2, respectively. Therefore, there is no friction loss due to the force generated in the axial direction in the bearing 11.

  In the first embodiment described above, the reaction force generated by pressurizing the pressure spring 9 is received by the ball bearing type ball bearing 10 through the retaining ring 17 outside the outer case. Yes. For this reason, this ball bearing 10 uses an expensive ball bearing in order to reduce friction loss. However, in the second embodiment, it is not necessary to use a ball bearing.

  Further, the rotating body side frictional sliding member 8a is bent at a position corresponding to the sliding portion. This is a means for widening the friction sliding area, reducing the surface pressure of the friction sliding surface, reducing wear of the friction material, and extending the life of the motor.

(Third embodiment)
FIG. 3 shows a third embodiment.

  In the third embodiment, similarly to the second embodiment, the rotating body 8 is provided at both ends of the vibrating body, and the holes on the small diameter side on the inner end side of each rotating body 8 are provided. Further, a slide bearing 22 composed of a slide bearing similar to the slide bearing 18 of the second embodiment is provided. The slide bearing 22 is made of resin and press-fitted into the aforementioned inner diameter of each rotating body 8. With this slide bearing 22, each rotating body 8 can also rotate without being eccentric with respect to the output shaft 2. As a result, the rotation unevenness of the motor is reduced.

  Further, in the present embodiment, slide bearing type slide bearings 32 are press-fitted into both ends of the inner diameter portion of the hollow bolt 1.

  The vibrating body support member 3 is sandwiched and fixed between the outer case portions 15 and 21.

  In addition to the piezoelectric element 4 and the vibrating body support member 3, the flexible printed board 20 is sandwiched and fixed between the two elastic members 5 and 6, and extends to the outside along the inner surfaces of the outer case portions 15 and 21. . This flexible printed circuit board 20 is used as wiring for supplying current to the piezoelectric element 4, current generated by the voltage generated by the piezoelectric element, and further supplying current to a rotational position detecting element such as a potentiometer.

DESCRIPTION OF SYMBOLS 1 Hollow bolt 2 Output shaft 3 Vibration body support member 4 Piezoelectric element 5,6 Elastic member 5a, 6a Vibration body side friction sliding member 7 Nut 8 Rotating body 8a Rotating body side friction sliding member 9 Pressure spring 10 Ball bearing bearing 11 Sliding Bearing 12 Rotation stop 13 Rotating plate 14 Photo interrupter 15 Outer case 16 Outer case 17 Stop ring 18 Slide bearing 19 Spacer 20 Flexible printed circuit board 21 Outer case 22 Slide bearing 23 Anti-vibration rubber

Claims (6)

Electrical - the vibration body to form a circular or elliptic motion by combining the mechanical energy conversion element and the vibrating body support member is fixed to the elastic member two bending vibrations, the pressure contact the circular or elliptic motion in said vibration member a rotating body that rotates, has an output shaft which passes through a through hole provided in said vibration member and said rotary member, in the vibration wave driving apparatus output shaft rotates in unison with the rotary member,
A case containing the vibrating body and the rotating body, and supporting the vibrating body via the vibrating body support member;
Provided in the casing, a plurality of bearings for rotatably supporting said output shaft,
Means for sandwiching the bearing from both sides and determining the position of the output shaft relative to the case;
Provided in the through-hole of the vibrating member, the vibration wave driving apparatus, characterized by chromatic and a bearing for supporting the output shaft.   The vibration wave driving device according to claim 1, further comprising a bearing provided in the through hole of the rotating body and supporting the output shaft. The vibration wave driving device according to claim 1, wherein the bearing provided in the through hole of the vibrating body is a sliding bearing. 4. The vibration wave driving device according to claim 1, wherein the bearing provided in the through hole of the vibrating body is made of resin. 5. 5. The vibration according to claim 1, wherein the bearing provided in the through hole of the vibrating body is disposed at a position that becomes a node of vibration of the two bending vibrations. 6. Wave drive device. A printed circuit board fixed to the elastic member for supplying a current to the electromechanical energy conversion element is provided so as to extend to the outside along the inner surface of the case.

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