JPH0619342Y2 - Surface wave motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a surface acoustic wave motor, and more particularly to a surface acoustic wave motor improved so that its casing can be made flat.

[Conventional technology]

The surface wave motor is a motor that has been developed relatively recently with the progress of semiconductor technology, and is characterized by low speed and large torque as compared with conventional motors that use electromagnetic attraction and repulsion. One of the features is that it does not require reduction gear means because it has low speed and large torque. In addition, since it has no brushes, it does not generate electrical noise, and because it does not have a magnetic iron core, it is small and lightweight, so it can be used as a drive source for vehicle-mounted auxiliary equipment. Is also expected for its future.

FIG. 2 is a schematic sectional view showing an example of a surface acoustic wave motor,
An annular elastic ring (made of metal) 13 to which an annular piezoelectric element 12 is fixed and an annular rotor 15 to which an annular slider (made of rubber) 14 are adhered face each other and are in contact with each other.

As shown in FIG. 3, the surface of the piezoelectric element 12 is circumferentially divided and symmetrically opposed to each other to provide electrodes A and B, and an earth electrode E in the middle thereof.

From the inverter, a sine wave voltage V ₀ sin is applied to the above electrode A.
In addition to giving ωt, a cosine wave voltage V ₀ cos ωt having a phase difference of 90 degrees is given to the electrode B. Then, a traveling wave due to bending vibration is generated in the elastic ring 13,
16 is driven in the direction opposite to the traveling wave.

When the polarity changeover switch 16 inverts the voltage waveform applied to the electrodes A and B, the rotation direction of the rotor 4 is inverted.

FIG. 4 is a vertical cross-sectional view showing a conventional example of a surface acoustic wave motor configured to be mounted on an automobile.

The stator assembly 1 is constructed by attaching a piezoelectric element 12 to an elastic ring 13, and is fixed to a main body 4a of the case 4.

The rotor assembly 2 is constructed by attaching a slider 14 to a rotor 15 and fixed to a shaft 3. In the present invention, an assembly is a so-called subassembly, which is a group of members assembled from a plurality of constituent members.

One end (upper end in the figure) of the shaft 3 is the case 4
It is inserted into the case 4 by penetrating the main body 4a and faces the inner wall surface of the lid 4b of the case 4.

The tip of the shaft 3 is rotatably supported by the case lid 4b via a bearing sleeve 6, and a thrust bearing 5 supports a load in the thrust direction.

A flange 3a is provided near the tip of the shaft 3, and the rotor assembly is attached to the flange 3a.

7 is a dust cover, 8 is packing, 9 is a spring,
10 is a bearing.

[Problems to be solved by the invention]

In the above-mentioned conventional example (FIG. 4), in order to house the bearing sleeve 6 and the thrust bearing 5, the case cover 4b is formed with the bulging portion 4b _-1, and the height dimension H of the case 4 as a whole is reduced. It's a big one.

In addition, it is difficult to connect both sides (upper side and lower side in FIG. 4) of this surface wave motor with electric wires. This causes a problem that it is difficult to pull out the electric wire from the mechanical portion driven by the surface wave motor (located below the case body 4a in this figure).

The present invention has been made in view of the above circumstances, and a bulging portion (4b _-1 in the above-mentioned conventional example) for housing the shaft support member, which can have a flat and thin case. It is an object of the present invention to provide a surface acoustic wave motor that can eliminate the above and flatten the entire structure, and that can easily draw out an electric wire from a mechanical portion driven by the surface acoustic wave motor.

[Means for solving problems]

To achieve the above object, in the surface wave motor according to the present invention, the bearing sleeve that supports one end of the shaft is not housed in the bulging portion of the case but is fitted in the through hole provided in the case. The thrust bearing is a plain bearing and is integrally connected to the bearing sleeve.

Further, the shaft is formed in a hollow tubular shape.

[Action]

By fitting the bearing sleeve into the through hole of the case, the bulging portion of the case is eliminated, and in addition to the fact that the thrust receiving member is a plain bearing, the overall shape is flat.

Further, the electric wire can be inserted through the hollow portion of the shaft and the through hole of the case.

〔Example〕

FIG. 1 is a sectional view showing an embodiment of a surface acoustic wave motor according to the present invention.

In this embodiment, the present invention is applied to the conventional surface acoustic wave motor shown in FIG. 4 and improved.

The same reference numerals as those in the conventional example (FIG. 4) are the same as or similar to those in the conventional example.

Next, differences from the conventional example (FIG. 4) will be described.

The dust cover 7 ', the packing 8', and the spring 9'shown with dashes are similar components corresponding to the dust cover 7, packing 8 and spring 9 in the conventional example (Fig. 4), respectively. is there.

The shaft 23 of this example is formed in a hollow tubular shape, is provided with a flange 23a slightly apart from the upper end thereof, and a journal 23b is provided above the flange 23a.

The flange 23a is a component corresponding to the flange 3a in the conventional example (FIG. 4).

The case lid 4b is provided with a through hole 4b _-1 , and the bearing sleeve 26 is fitted and fixed. Fixing in this case is as much as positioning as it is, and it is not sufficient to provide a means for locking rotation. The bearing sleeve 26 rotatably supports the journal 23b.

A flange-shaped thrust receiving portion 26a is formed at the lower end of the bearing sleeve 26 to receive the thrust of the shaft 23.

As a result, the thickness h of this embodiment (FIG. 1) is significantly reduced as compared with the size H of the conventional example (FIG. 4), and the overall shape becomes flat.

Further, the electric wire 27 can be inserted as shown by a virtual line.

[Effect of device]

As described above, the surface wave motor to which the present invention is applied has a thin casing as a whole without a bulging portion in the casing. Moreover, the electric wire can be easily pulled out from the component driven by the surface wave motor through the surface wave motor.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of the surface acoustic wave motor of the present invention. 2 and 3 are principle explanatory views of a known surface wave motor. FIG. 4 is a vertical sectional view of a conventional surface acoustic wave motor. 1 ... Stator assembly, 2 ... Rotor assembly, 3, 3 '
...... Shaft, 4,4 '... Case, 4a ... Case body, 4b, 4b' ... Case lid, 4b _-1 ... Perforation hole, 5 ...
Thrust bearing, 6 ... Bearing sleeve, 7, 7 '...
... Dust cover, 8,8 '... Packing, 9,9' ...
Spring, 10 ... ball bearing, 23 ... tubular shaft, 26 ... bearing sleeve, 26a ... thrust receiving part, 2
7 ... electric wire.

Claims (1)

[Scope of utility model registration request] 1. A stator assembly is fixed to a case; (b) A rotor assembly is fixed to a shaft which penetrates a wall of the case and has one end inserted into the case; ) In a surface wave motor in which an end portion of the shaft is rotatably supported with respect to the case via a bearing sleeve and a thrust bearing, (d) the shaft is formed into a hollow tubular shape, and (e) The thrust bearing is a plain bearing, the plain bearing is integrally connected to the bearing sleeve, and (f) a through hole is provided in the case, and the bearing is provided in the through hole. A surface wave motor characterized in that a sleeve is fitted and fixed.