JP3283756B2 - Ultrasonic motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic motor, and more particularly, to an ultrasonic motor having a piezoelectric element for applying ultrasonic vibration to a driver for rotationally driving a rotor serving as a load. is there.

[0002]

2. Description of the Related Art FIG.
91893) is a conventional ultrasonic motor, and in the figure, a polarization mark is formed on a disc-shaped substrate 21 made of an elastic body such as a metal.
Four piezoelectric elements 22 distributed evenly by printing
The four driving elements 23 are arranged at a constant distance from each other, and the rotor 24 is pressed against this. With the above configuration, ultrasonic vibration is generated in the piezoelectric element 22 to rotate the rotor 24 in one direction.

[0003]

In the conventional ultrasonic motor as described above, it is difficult to switch the rotation direction of the rotor because the mutual operation relationship between the piezoelectric element for excitation and the driver is constant. SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problem, and an object of the present invention is to provide a small, thin, and highly mass-produced ultrasonic motor capable of freely controlling the rotation direction of a rotor.

[0004]

According to a first aspect of the present invention, there is provided a
The sound wave motor is placed on the substrate on the disk or on the top of the piezoelectric material.
At least one of which is placed and forms a polarized printed main vibration system
A set of first piezoelectric elements and one each of the first piezoelectric elements
Correspondingly placed on the lower surface of the substrate or piezoelectric material, the first
And two piezoelectric elements, each of which is polarized and printed with a different polarity.
A second piezoelectric element of a switching system disposed, and the first piezoelectric element
A driving element coupled to the boundary of the element and driving the rotor to rotate;
Comprising the first piezoelectric element and one of the second
When the piezoelectric element is subjected to bending vibration in parallel with the
Node line generated by piezoelectric element and second piezoelectric element
Nodal due to resultant force with node line caused by child
In the main vibration system as a node line.
The second piezoelectric element vibrates in addition to the vibration of one piezoelectric element.
By selectively switching the element, the node
Biasing the drive to either side of the driver
The direction of rotation of the data is switched.

[0005] A second ultrasonic motor according to the present invention has a circular shape.
Piezoelectric element that forms one of plate, ring and cylinder
Of the main vibration system printed diagonally on the surface of the
Even number of first piezoelectric elements and that of this first piezoelectric element
Two switching systems each on the scissors corner corresponding to each
A second piezoelectric element, and a rotor coupled to the first piezoelectric element.
A driving element for rotationally driving the motor.
Element and one of the second piezoelectric elements in parallel
When bending vibration occurs, noise generated by the first piezoelectric element
And the node line generated by the second piezoelectric element.
The node line of the main vibration system
And contribute to the vibration of the first piezoelectric element.
To selectively switch the second piezoelectric element that vibrates
More the node line of the main vibration system on both sides of the driver
The direction of rotation of the rotor is switched by biasing to either direction.
It is.

A third ultrasonic motor according to the present invention is a circular ultrasonic motor.
Substrate made of a plate-like, annular or cylindrical elastic body
And the polarization-printed main vibration arranged on the diagonal of this substrate
An even number of first piezoelectric elements of the system and
Each two placed on the corresponding scissors corner
A second piezoelectric element of a switching system mounted and supported on the substrate,
A driver coupled to the first piezoelectric element to rotationally drive the rotor
And the first piezoelectric element, and one of the first
When the two piezoelectric elements are placed in parallel and subjected to bending vibration, the first
The node line generated by the piezoelectric element of
Node due to resultant force with node line generated by element
Line as the main vibration node line,
The second pressure oscillating in addition to the vibration of the first piezoelectric element
By selectively switching the electric element, the node of the main vibration system
The line is biased to either side of the driver,
The direction of rotation of the motor is switched.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (Embodiment 1) FIGS. 1 and 2 show a first embodiment of the present invention. In FIG. As shown in FIG. 1A, the first piezoelectric elements 2a and 2b of the main vibration system, which are divided into 分割 and polarized positively and negatively, respectively,
On the lower surface, as shown in FIG. 3B, the second piezoelectric elements 3a and 3b and 4a and 4b of the switching system are provided with the first piezoelectric element.
The polarities are different from each other, and the polarizers are divided into four parts with the polarization shown in the figure, and are attached. That is, two second piezoelectric elements are arranged corresponding to each of the even number of first piezoelectric elements. In general, these piezoelectric elements are formed by dividing a single piece of piezoelectric ceramic plate into electrodes, and performing polarization processing to a predetermined polarity, thereby substantially forming a plurality of piezoelectric elements. Of course, the separated piezoelectric elements may be individually attached to each other. The polarities and positions in FIG. 1B are perspective views from the upper surface, and are matched so that bending occurs in the same direction when driven in parallel within the same position on the upper and lower surfaces. The drivers 5a and 5b are coupled at a concentric distance on the boundary between the piezoelectric elements 2a and 2b. Also, substrate 1
Is located on the line of the node of vibration (hereinafter simply referred to as “node line
Above. " ) , The vibration loss is small even if it is used with a hole for fixing the assembly.

Next, the operation will be described. In FIG. 1, the bending state of the divided pattern of the piezoelectric element at the time of vibration is indicated by a circle and a triangle. In other words, when the half area on the side of the circle is bent upward, the other half of the area is bent downward, and the pattern is shown by a D1-D2 cross section in FIG.
(C). Now, the first piezoelectric elements 2a, 2b
When the second piezoelectric elements 3a and 3b are arranged in parallel to bend and resonate, only the piezoelectric elements 2a and 2b attempt to form a vibration node line on the line A1-A2 shown in FIG. , 3b alone, B1-B2 shown in FIG.
Try to make a node line of Since the actual vibration occurs at the same time, the combined node line is C1-
C2 is generated near the A1-A2 line by an amount corresponding to the strength of the piezoelectric element on the upper surface being stronger than the intermediate position between the two.

FIG. 2 shows the movement of the driver 5a during this period. FIG. 2 (a) shows the case where the node lines are A1-A2, and FIG. 2 (b) shows the case where the piezoelectric elements 3a and 3b are involved and the node line is C1. -C2. That is, the driver element 5a is only brought into the swing just to the left and right vibration of the substrate 1 in Fig. (A), when leading to FIG (b) Nodora
Since in is C1-C2, the vertical direction is y, the horizontal direction
It is displaced simultaneously with Дx in the direction. At this time, the rotor (not shown) in contact with the driver 5a receives a rightward force, and rotates leftward as viewed in FIG. Also, at this time, the other driver 5b is in a direction of descending, so that it is in a posture of moving away from the rotor. Thus, in the next half cycle, the reverse is now true, with the driver 5b working and the driver 5a resting, thus alternately rotating the rotor counterclockwise.

Next, for reverse rotation, if the lower piezoelectric element is switched to the second piezoelectric elements 4a and 4b in FIG. 1B, the node line is generated on the opposite side of the driver 5a. ,
The driver 5a in FIG. 2B has the opposite inclination, and the clockwise rotation of the rotor is achieved. The same applies to the driver 5b. As described above, switching of the rotation direction of the rotor can be performed by switching of the second piezoelectric element,
In addition, since the object can be achieved by energizing the bending operation, the efficiency is high.

(Embodiment 2) The structure shown in FIG.
The disk-shaped member can be formed only by the piezoelectric element which is disposed on the surface of the piezoelectric material and is polarization printed without using the piezoelectric element. In particular, in order to reduce the size and cost, it is preferable that the piezoelectric elements on the upper and lower surfaces are directly bonded to each other as in the case of the half-split system in FIG. FIG. 3 is an equivalent circuit diagram at this time, and reference numerals correspond to those in FIG. The piezoelectric elements on the upper and lower surfaces are electrically separated from each other, and the change-over switches SW1 and SW2 are two double-sided switches. In the manufacture of a piezoelectric element, usually, a long bar-shaped porcelain is sliced after the polarization treatment, and then the electrode treatment is performed. Since the QM of the material becomes the QM of the piezoelectric element structure as it is, it is necessary to select a large value and suppress vibration loss and heat generation.

(Embodiment 3) FIG. 4 shows an embodiment at the time of 1/4 division. The polarity of the first piezoelectric element is different from that of the first piezoelectric element. Two pairs of first piezoelectric elements 6a, 6b of the main vibration system are provided on the upper surface of the four pairs of second piezoelectric elements 7a, 7b, 7c of the switching system. , 6
7d and 8a, 8b, 8c and 8d are arranged on the lower surfaces c and 6d. Drivers 9a, 9b, 9c, 9d are connected to the boundary portion of the first piezoelectric element. The polarization polarity shown in FIG. 2B is arranged such that a bending mode as shown in FIG. Drivers 9a, 9b and 9b, 9c, when one works, the other rests, and alternates as in FIG. Polarization can be used in series with the same polarity. The number of drivers may be two.

(Embodiment 4) In order to further increase the power, the number of divisions can be increased as the diameter is increased. In the 1/6 division shown in FIG. 5, six drivers can be connected. Although not shown,
In the 1/8 split, every other two sets of eight drivers are alternately operated to kick out and rotate the rotor in an arbitrary direction. In the vibration mode of the present invention, the resonance frequency is proportional to the finished thickness of the disk and substantially inversely proportional to the square of the diameter. The center hole is hardly affected.

(Embodiment 5) FIG. 6 shows that one piezoelectric element is 1 /
A wide-angle first piezoelectric element 10a, 10b of the main vibration system, and a narrow-angle second piezoelectric element 11a, 11b and 12a, 12b of the main vibration system are provided only on the upper surface of the substrate 1.
Is provided. Now, the second piezoelectric elements 11a, 11
When b is applied to the first piezoelectric elements 10a and 10b in parallel, the node lines are deviated and the rotor rotates clockwise, and the piezoelectric elements 12a and 12b rotate counterclockwise. 5a and 5b are drivers. In the case of this embodiment, since only one piezoelectric element material is required, it is suitable for low cost and light load. Substrate 1
There is also an advantage that a workpiece or the like can be directly attached to the lower surface of the device.

(Embodiment 6) In the present invention, the shape of the piezoelectric element structure may be annular (donut-like) or cylindrical. FIG. 7 shows a case of a cylinder half-split. In the figure, second piezoelectric elements 14a, 14b and 15a, 15b of a switching system are disposed on the outer surface and inner surface of a cylindrical substrate 16 with respect to the first piezoelectric elements 13a, 13b of the main vibration system. Have been. The electrodes of the piezoelectric element are not shown. Driver 17
a and 17b are provided inside the cylinder so as to face each other. The operation is exactly the same, in which the disk is vibrated up and down in a radial area, whereas in the case of a cylinder, the difference is whether the entire area in the length direction of the cylinder bends further outward or inward. The mounting of the piezoelectric element on the cylindrical curved substrate is performed by a sputtering method or a hydrothermal method. A structure in which the layers are laminated only on the outer peripheral surface may be used. The location of the driver is not limited to the inner and outer peripheral surfaces, and there is no restriction on the length. In the ring shape, it is considered that the center hole of the disk is enlarged, and the operation behavior is similar to that of the disk.

[0016]

As is apparent from the above description, the present invention relates to a first piezoelectric element for generating a thrust on a driver and a switching system for vibrating by adding to the main vibration of the first piezoelectric element. Since the second piezoelectric element is provided and the node line of the main vibration is displaced to one of the two sides of the driver by switching the second piezoelectric element, there is no loss that is wasted on unnecessary vibration components, and the rotation of the rotor is reduced. The direction can be switched. further,
There are effects such as high efficiency, low cost with good mass productivity, and thin and various sizes can be easily obtained.

[Brief description of the drawings]

FIG. 1A is a top view, FIG. 1B is a bottom view, and FIG. 1C is a waveform chart of Embodiment 1 of the present invention.

FIG. 2 is an operation waveform diagram according to the first embodiment of the present invention.

FIG. 3 is a circuit diagram according to a second embodiment of the present invention.

4A is a top view, FIG. 4B is a bottom view, and FIG. 4C is a waveform chart of Embodiment 3 of the present invention.

5 (a) is a top view and FIG. 5 (b) is a waveform chart of Embodiment 4 of the present invention.

FIG. 6 is a top view of a fifth embodiment of the present invention.

FIG. 7 is a front view of a sixth embodiment of the present invention.

8A is a top view and FIG. 8B is a side sectional view of a conventional ultrasonic motor.

[Explanation of symbols]

 1 Substrate 2a, 2b First piezoelectric element 3a, 3b, 4a, 4b Second piezoelectric element 5a, 5b Driver 6a, 6b, 6c, 6d First piezoelectric element 7a, 7b, 7c, 7d Second piezoelectric element Element 8a, 8b, 8c, 8d Second piezoelectric element 9a, 9b, 9c, 9d Driver 10a, 10b First piezoelectric element 11a, 11b, 12a, 12b Second piezoelectric element 13a, 13b First piezoelectric element 14a, 14b, 15a, 15b Second piezoelectric element 16 Substrate 17a, 17b Driver

Claims (3)

(57) [Claims] 1. A substrate on a disk or an upper surface of a piezoelectric material
At least one pair forming a polarized and printed main vibration system
Pair of the first piezoelectric element and one of the first piezoelectric elements.
Correspondingly placed on the lower surface of the substrate or piezoelectric material
Arranged two by polarization printing with different polarity from the piezoelectric element
Switched second piezoelectric element and the first piezoelectric element
And a driving element coupled to the boundary of
Comprising, the first piezoelectric element, one of the second
When bending vibration is performed with the piezoelectric element in parallel, the first pressure
Node line generated by the piezoelectric element and the second piezoelectric element
Node line due to the resultant force with the node line
Is generated as a node line of the main vibration system.
The second piezoelectric element vibrating in addition to the vibration of the piezoelectric element
Node switching of the main vibration system
The rotor to either side of the driver,
Ultrasonic motor that switches the rotation direction of the motor. 2. The method according to claim 1, wherein the disk-shaped, annular or cylindrical shape is selected.
Polarized printed on the diagonal of the surface of the piezoelectric material to be formed
Even number of first piezoelectric elements of the main vibration system
Each 2 placed on the scissors corner corresponding to each of the piezoelectric elements
A second piezoelectric element for each switching system, and the first piezoelectric element;
A driving element coupled to the driving element to rotationally drive the rotor.
The first piezoelectric element described above and one of the second piezoelectric elements
And in parallel bending vibration, the first piezoelectric element
The resulting node line and the second piezoelectric element
Maintain the node line due to the resultant force with the resulting node line
The first piezoelectric element is generated as a dynamic system node line.
Select the second piezoelectric element that vibrates in addition to the vibration of the child
By switching, the node line of the main vibration system is
Rotating the rotor by biasing it to either side of the driver
Ultrasonic motor that switches direction. 3. A disc-shaped, annular or cylindrical bullet
And a polarization mark placed on the diagonal of this substrate
An even number of the first piezoelectric elements of the main vibration system
It is arranged on the scissors corner corresponding to each of the one piezoelectric element
The second pressure of the switching system mounted and supported on the substrate by two each.
Rotating the rotor coupled to the piezoelectric element and the first piezoelectric element.
A driving element for driving, the first piezoelectric element,
One of the two piezoelectric elements is placed in parallel with
Caused by the first piezoelectric element
And the node line generated by the second piezoelectric element
Node line by force as node line of main vibration system
And vibrates together with the vibration of the first piezoelectric element.
By selectively switching the second piezoelectric element,
Place the node line of the vibration system on either side of the driver
An ultrasonic motor that switches the rotation direction of the rotor by biasing
Ta.