JPH11206155A - Ultrasonic motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to reduce the cost of parts, by reducing number of parts and man-hours in a manufacturing step. SOLUTION: An ultrasonic motor includes an annular stator block made up of an annular stator 2 and a supporting member 21 with an inner circular circumferential face, on which the stator 2 is fixed, a rotor block made up of a rotor 3 driven rotatively by the stator 2, and a holder ring 22 with a pivotally supporting face on an outer circular circumferential face. The supporting member 21 has a screw part 21a tightened with a base member on an inner circumferential face thereof. The holder ring 22 has a fitting part 22d fitted to the supporting member 21 and a screw part 22b tightened with the supporting member 22. Then the supporting member 21 and the holder ring 22 are directly tightened with the screw parts 21a and 22b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an annular ultrasonic motor having an improved stator block fixing method.

[0002]

2. Description of the Related Art FIG. 3 is a longitudinal sectional view showing a conventional example of an annular ultrasonic motor. The holder ring 1 is a member on which the stator block SB is mounted.
The holder ring 1 has an outer peripheral surface 1a and screw portions 1b and 1c.
And a contact surface 1d. The inclination of the screw portion 1b with respect to the outer peripheral surface 1a is suppressed by component precision. Further, the inclination of the contact surface 1d with respect to the screw portion 1b is suppressed by component precision.

[0003] The stator block SB includes a stator 2 and
It is a block including a support member 19. The stator 2
It is a stator of an ultrasonic motor, and a piezoelectric element 17 for applying excitation is affixed thereto. The stator 2 is adhered to the support member 19 by a joint 2a.

The support member 19 is a member for supporting the stator 2, and includes a fitting surface 19a, a groove 19b, and a space 19c.
And a vertical surface 19d and the like. Mating surface 19a
Is a portion for fitting the support member 19 to the outer peripheral surface 1a of the holder ring 1. The groove 19b is formed in the inner peripheral portion of the support member 19 in a comb-like shape in the circumferential direction, so that the convex portion 20a of the press ring 20 is fitted.
That is, the support member 19 has a structure in which it is movably engaged with the holder ring 1 in the axial direction and does not rotate in the radial direction. This is because when the stator block SB tries to rotate the rotor 3,
This is to prevent the stator block SB itself from rotating.

The holding ring 20 is a member for holding the stator block SB so as not to come off from the holder ring 1. The holding ring 20 includes a projection 20a, a space 20b, a vertical surface 20c,
And a screw portion 20d. The screw portion 20d is connected to the screw portion 1b of the holder ring 1 by screw connection.

The power supply brush block 14 includes a power supply board 15
Block that supplies power to the The power supply board 15 is fixed to a side of the holding ring 20 opposite to a surface on which the support member 19 of the stator 2 abuts. Power supply board 15 and piezoelectric element 1
7 is electrically connected to a power supply space 20b of the press ring 20 and a power supply space 19c of the support member 19 by a lead wire (not shown) or the like.

[0007] The rotor 3 is a rotor of an ultrasonic motor, and has an inner diameter portion 3a, a contact portion 3b and the like. The rotor 3 has a sliding member 4 attached to a contact portion 3b with the stator 2. The inner diameter portion 3 a of the rotor 3 is fitted to the small diameter portion 5 a of the rotor support ring 5, and the rotor 3 is attached to the rotor support ring 5 with a fixing tape 8 via a buffer member 9.

The rotor support ring 5 is a member for supporting the rotor 3 and includes a small-diameter portion 5a, an inner peripheral surface 5b, and space portions 5c provided at three locations in the circumferential direction. I have. The inner peripheral surface 5b is fitted to the outer peripheral surface 1a of the holder ring 1. That is, the rotor support ring 5 is movable in the axial direction and rotatable in the circumferential direction.
Are fitted and arranged. A drive lever 6 for transmitting rotation to the outside of the motor block is directly attached to the rotor support ring 5 by a screw 7.

The pressurizing spring 11 is for generating a necessary pressing force between the stator 2 and the rotor 3 by the pressing force. For example, a wave washer is used. The pressure spring 11 has one side (the left side in FIG. 3) abutting on the bearing 16 via the holding washer 10, and the other side (the right side in FIG. 3) is pressed by the spring holding ring 12. The spring holding ring 12 is connected to the screw portion 1c of the holder ring 1 by screw connection. Adjustment ring 1
Reference numeral 3 denotes a member for adjusting the pressing force of the pressing spring 11, and the pressing force is adjusted by changing its thickness.

The bearing 16 has a structure for receiving the pressing force of the pressure spring 11, and is provided with a space 5 of the rotor support ring 5.
c, is fixed to the fixing screw 18. For this reason, the rotor support ring 5 receives the pressing force by the bearing 16 so that the load loss is sufficiently reduced.

That is, the rotor support ring 5 is always pushed forward in the axial direction by the pressure spring 11 through the buffer member 9 by screwing the spring holding ring 12 to the holder ring 1. Due to the pressing force, the rotor 3 and the stator 2 are in frictional contact with each other via the sliding member 4.

[0012]

However, due to the characteristics of the ultrasonic motors described above, the contact surfaces 2a (with the rotor 3) of the stator 2 which are pressed against each other and are in frictional contact with each other,
It is necessary that the sliding member 4 attached to the rotor 3 is in uniform contact. Therefore, the allowable inclination amount with respect to the contact surface 2a of the stator 2 (with the rotor 3) and the outer peripheral surface 1a of the holder ring 1, which is the fitting surface of the rotor support ring 5, is very small.

Due to this characteristic, the conventional ultrasonic motor is required to have the following accuracy. (1) The vertical accuracy of the vertical surface 19d of the support member 19 and the allowable amount of verticality with respect to the fitting surface 19a must be kept small at the intersection of the parts. (2) The surface accuracy of the vertical surface 20c of the press ring 20 and the allowable amount of verticality with the screw portion 20d must be kept small by the intersection of the parts. (3) The tolerance of the inclination of the threaded portion 1b with respect to the outer peripheral surface 1a of the holder ring 1 must be kept small at the intersection of the parts.

Further, a comb-shaped groove 19b is required in the inner peripheral portion of the support member 19 in the circumferential direction.
Requires a projection 20a. As described above, the number of steps for processing the parts of the support member 19 and the presser ring 20 is significantly increased, and the cost of parts is increased. Further, the presser ring 20 itself is required.

Accordingly, the present invention is to reduce the number of processing steps and the number of parts themselves, while maintaining the accuracy of the contact surface between the stator member and the rotor member and the amount of inclination of the stator member, thereby reducing the cost of parts. It is an object to provide an ultrasonic motor that can be used.

[0016]

In order to solve the above-mentioned problems, a first aspect of the present invention provides a support member (21) having an annular stator member (2) and a circular inner peripheral surface to which the stator member is fixed. ), A rotor block including a rotor member (3) that is brought into pressure contact with one end of the stator member and is driven to rotate by the stator member, and the stator block is fixed. An ultrasonic motor comprising: a base member having a circular outer peripheral surface for rotatably supporting a rotor block; wherein the support member is screwed to the base member on the circular inner peripheral surface. (21a) is formed, and the base member (22) is provided with a locking portion (2) for locking the support member.
2d) and a screw portion (22b) for fastening to the support member are formed, and the support member and the base member are directly fastened by the respective screw portions (21a, 22b). It is.

According to a second aspect of the present invention, in the ultrasonic motor according to the first aspect, the base member has the screw portion and the locking portion provided on the circular outer peripheral surface. It is an ultrasonic motor.

According to a third aspect of the present invention, there is provided the first or second aspect.
5. The ultrasonic motor according to claim 1, wherein the support member is provided with a power supply encoder on a surface on the opposite side to which the stator member is fixed.

[0019]

FIG. 1 is a view schematically showing an embodiment of an ultrasonic motor according to the present invention, and FIG. 2 is a view of a support member 21 viewed from a direction B in FIG. Note that the same reference numerals are given to portions that perform the same functions as the above-described conventional example, and
Duplicate descriptions will be omitted as appropriate, and mainly, differences from the conventional example will be described.

The support member 21 has a screw portion 21 on its inner peripheral portion.
a, and a contact surface 21 that maintains the vertical accuracy with the screw portion 21 a inside the mounting portion side of the power supply board 15.
b is provided.

On the other hand, the holder ring 22 is
And a contact surface 22 maintaining vertical accuracy with the screw portion 22b.
e and a convex portion 22d having e. Screw part 22b
The inclination of the holder ring 22 with respect to the outer peripheral surface 22a is suppressed by the component accuracy.

The support member 21 does not engage with the holder ring 22 in diameter, but the screw portions 21a and 22b are screwed together.
When the contact surface 21b contacts the contact surface 22e, it is directly fixed to the holder ring 22 by screwing.

At this time, the contact surface 2b (with the rotor 3) of the stator 2 which is in frictional contact by pressurization, and the rotor 3
The function of uniformly contacting the sliding member 4 attached to the sliding member 4 is not impaired. Further, since the support member 21 and the holder ring 22 are directly fixed, the rotation of the support member 21 due to the reaction force at the time of starting the motor does not occur.

The power supply board 15 is fixed to the support member 21 on the side opposite to the surface to which the stator 2 is bonded.
The power supply board 15 and the piezoelectric element 17 are electrically connected to each other by a lead wire or the like (not shown) using the power supply space 21 c of the support member 21. Here, the length from the joining portion 2a of the stator 2 to the power brush block 14 is smaller than that of the conventional example (L1 <L2) by the omission of the press ring 20 of the conventional example.

As described above, according to the present embodiment, the support member 21 is provided with the screw portion 21 a on the inner peripheral surface thereof, and the screw portion 2 a is provided inside the mounting portion of the power supply board 15.
A contact surface 21b which maintains vertical accuracy with respect to 1a,
The holder ring 22 has a contact surface 22 that maintains vertical accuracy with a screw portion 22b that contacts the contact surface 21b of the support member 21.
Since the projections 22d provided with e are provided, the support member 21 to which the stator 2 is attached can be directly fixed to the holder ring 22, and the holding ring 20 is not required.

Further, since the support member 21 is directly screwed to the holder ring 22, it is possible to prevent the support member 21 from rotating due to a reaction force when the motor is started, and the shape of the support member 21 itself is simple. And the number of processing steps can be reduced.

Accordingly, the ultrasonic motor according to the present embodiment does not require the holding ring 20 and can reduce the number of processing steps, so that the cost can be reduced and the components of the motor block itself can be reduced. Downsizing is also possible.

[0028]

As described above in detail, according to the present invention, the shape of the support member itself becomes simple, and the number of processing steps can be reduced, so that the cost can be reduced and the number of components of the component can be reduced. This has the effect of enabling small size.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an embodiment of an ultrasonic motor according to the present invention.

FIG. 2 is a view of the support member 21 viewed from a direction B in FIG.

FIG. 3 is a schematic sectional view showing a conventional ultrasonic motor.

[Explanation of symbols]

 Reference Signs List 2 Stator 3 Rotor 4 Sliding member 5 Rotor support ring 21 Support member 21a Screw portion 21b Contact surface 22 Holder ring 22a Outer peripheral surface 22b Screw portion 22d Convex portion 22e Contact surface

Claims (3)

[Claims] An annular stator block including an annular stator member and a support member having a circular inner peripheral surface to which the stator member is fixed; An ultrasonic motor comprising: a rotor block including a rotor member driven to rotate by a member; and a base member having a circular outer peripheral surface that fixes the stator block and rotatably supports the rotor block. A screw portion to be fastened to the base member is formed on the inner circumferential surface of the circular shape; and a locking portion for fastening the support member and a screw portion to be fastened to the support member are formed on the base member. An ultrasonic motor, wherein the member and the base member are directly fastened by the respective screw portions. 2. The ultrasonic motor according to claim 1, wherein the screw portion and the locking portion of the base member are provided on the circular outer peripheral surface. 3. The ultrasonic motor according to claim 1, wherein the support member has a power supply encoder provided on a surface on the opposite side to which the stator member is fixed. Ultrasonic motor characterized.