JPS63217980A - Structure of wave motor - Google Patents

Abstract

PURPOSE:To reduce the size, thickness and power of a wave motor by sticking a magnetic detector to part of a toothed section, and detecting a magnetic flux change due to the rotation of a moving element. CONSTITUTION:In a circular wave motor, a cutout 3 is formed on a ring-shaped permanent magnet 1 magnetized elevationally, and bonded to a nonmagnetic round ringlike plate 2. The plate 2 and the magnet 1 are matched to form a moving element. An electrostrictive element 6 made of polarized piezoelectric ceramics is bonded to the lower surface of a vibrator 4, an electric signal is applied to the pole to form a traveling wave. The vibrator 4 is formed at the contacting part with the moving element in a pectinated state to increase the width. A Hall element 5 is formed in the recess of the pectinated teeth. Thus, the position detection of the element with the magnet can be performed in a simple structure with low power consumption, thereby reducing the thickness, the size and the power consumption.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a structure for detecting the position of a moving body in a wave motor that drives a moving body by progressive waves generated in a vibrating body, and particularly relates to a structure for detecting the position of a moving body. It concerns the structure of moving bodies and vibrating bodies.

[A essential point of the invention]

The present invention provides a wave motor in which a permanent magnet is disposed in a part of a moving body, and in a vibrating body whose contact portion with the moving body has divided peaks (for example, comb teeth), a part of the peaks is provided. A magnetic detection element is fixed to the magnetic flux sensor to detect changes in magnetic flux due to the rotation of the moving body, thereby making it possible to detect the position of the moving body.

[Conventional technology]

Conventionally, there has been a method of detecting the position of a moving object by providing a slit in a gear attached to the output shaft of a wave motor and using a photodetector to detect the light passing through the slit plate, as in JP-A No. 61-189175. , Japanese Patent Publication No. 60-113
675, a through hole is provided in a part of the disc-shaped moving body of the wave motor, and the rotation angle of the moving body is determined by whether the light from the light emitting diode is irradiated to the phototransistor through the through hole. Both embodiments in which a detection method has been invented have a light source such as a light emitting diode, a photodetector such as a phototransistor, and a through hole for light that rotates by the rotation of the moving body. .

[Problem that the invention seeks to solve]

In the above structure, since a light source such as a light emitting diode is used, energy is required to cause the light emitting diode to emit light when detecting the position of a moving object. Although wave motors themselves are highly efficient and suitable for reducing power consumption, they require electric power to detect the position of moving objects, so they are not suitable for reducing power consumption in systems such as motors for electronic watches. Due to the thickness of the diode, it has the disadvantage that it is not suitable for making the motor thinner.

[Purpose of the invention]

The object of the present invention is to use a wave motor that can accurately display the position of the hands with low power consumption, such as the motor that drives the hands of an electronic watch, in a small, thin, low-power manner, and that can accurately detect the position of a moving object. The goal is to realize this with a simple structure and at low cost.

[Means for solving problems]

In order to solve the above problems, in the present invention, a permanent magnet is attached to the movable body and a magnetic detection element is housed in the comb teeth of the vibrating body, thereby making the movable body position Tl detection wave motor thin and Achieved low power consumption with a simple structure.

(Function) According to the above configuration, when the moving body rotates, the permanent magnet attached to the moving body also rotates. Magnetic flux changes or magnetic pole polarity changes occur due to rotation, such as by cutting a part of a permanent magnet or using a magnet that is polarized alternately between N and S poles. An electromotive force due to the Hall effect or an induced electromotive force due to rotation is generated in the detection element, making it possible to detect the position of the moving object.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a perspective view of an annular wave a1 motor according to the present invention. A ring-shaped permanent magnet 1 magnetized in the vertical direction has a cutout 3 and is adhered to a non-magnetic rounded temporary 2. In FIG. 1, for the sake of explanation, the hunting part lO
shows the cut surface. A non-magnetic round ring-shaped plate 2 and a permanent magnet are combined to form a moving body. The moving body is vibrating body 4
Although not shown in this embodiment, a friction material having a large PJ friction coefficient and wear resistance is bonded to the moving body between the vibrating body 4 and the moving body. A polarized piezoelectric ceramic i-strain element 6 is bonded to the lower surface of the . When electrical signals having temporally different phases are applied to each column of the electrostrictive element 6, the combined wave forms a progressive wave, and the position of the wave formed on the upper surface of the vibrating body 4 moves with time. The vibrating body 4 has its contact portion with the movable body shaped like a tooth to increase the amplitude. A Hall element 5 is bonded to the top surface of the tooth. From the Hall element, a beam 7
2 and 3 show how the Hall element 5 is fixed to the S moving body 4. The Hall element 5 is fixed to a recess provided in the comb teeth of the vibrating body. There is.

The top surface of the Hall element 5 is about 50 degrees from the top surface of the comb teeth of the vibrating body 4.
It is concave by μm. As a result, the Hall element 5 becomes
The reason why the Hall element 5 is fixed to the inner circumferential side of the comb teeth of the vibrating body 5, which does not come into direct contact with the moving body 4, is that the outer periphery of the comb teeth has a large amount of displacement, which increases the driving force applied to the moving body. Therefore, we left comb teeth on the outer periphery to obtain driving force.

In FIGS. 1, 2, and 3, the vibrating body 4 is not necessarily made of a magnetic material (or may be used; FIG. 4 is another example of a magnet for a moving body). A structure in which the magnetically polarized plastic magnet 8 is polarized to 60 or 120 poles and fixed to a non-magnetic ring-shaped plate to form a moving body, and a structure in which the plastic magnet 8 alone is used as a moving body are possible.

Position detection at a rotation angle of 6° is possible by detecting both polarized north and south poles or by detecting only the north pole. In systems such as electronic watches where the second hand and minute hand are directly driven by this wave motor, either a motor that rotates exactly once per minute or hour, or a wave motor that is driven in steps corresponding to minute and second scales is used. It becomes necessary. A general wave motor cannot be used as is because the speed of the moving body varies depending on the applied voltage, load conditions, etc. Therefore, it is necessary to provide a position detection means in the moving body for control.

FIG. 5 shows a structure in which the position of a moving object can be detected using a coil without using a Hall element. Vibrating body 4 made of high magnetic permeability material
A recess is provided in a part of the recess, a wire 9 is wound around the recess, and the position of the movable body is detected by detecting the induced voltage generated when the movable body rotates. This recess is located below half the height of the comb teeth of the vibrating body 4. Since the vibration on the bottom surface is reduced, fatigue breakage of the wire due to vibration can be prevented. FIG. 6 is a perspective view of a moving body showing another embodiment. A rectangular permanent magnet 10 magnetized in the circumferential direction is placed on a non-magnetic ring-shaped plate 2. FIG. 7 is a sectional view of the vibrating body 4 and the movable body of the embodiment shown in FIG. 6. The length of the permanent magnet in the magnetization direction is approximately equal to the length of the comb teeth of the vibrator. In this way, a magnetic flux loop is formed in which the magnetic flux from the north pole passes through the a teeth of the comb teeth and returns to the south pole via the b teeth. When a coil 9 is wound around this a-tooth, the coil 9 detects changes in magnetic flux caused by rotation of the moving body. This method of detecting the position of a moving body using the induced voltage in the coil requires less power consumption because it is not necessary to flow current through the coil for detection.

Although this example shows a square permanent magnet fixed on the non-magnetic ring-shaped plate 2, the effect remains the same even if the magnet is embedded in the non-magnetic ring-shaped plate 2. The reason for winding the wire 9 there is to provide a space for winding the wire since there is a narrow gap between the mountains, and also to prevent the winding from breaking. In Fig. 7, a coil is used as a magnetic detection means. However, it is also easy to use the Hall element of the embodiment shown in FIG. 4 as a magnetic detection means.

〔Effect of the invention〕

As explained above, this invention has a simple structure for detecting the position of a moving body with a magnet and can detect the position with low power consumption by housing a magnetic detection element in the comb teeth of a vibrating body that comes into contact with a moving body. Thin, compact, low power consumption, L
OW Co5t is highly effective as a motor for electronic watches where the position of a moving object must be accurately informed.

Further, according to the embodiment in FIG. 1, if the vibrating body is made of a magnetic material,
Since the moving body and vibrating body are pressurized by the absorption force of the magnet,
It also has the effect of making it possible to move Jl% without using any special pressure means.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of an annular wave motor showing an embodiment of the present invention, Fig. 2 is a partial sectional view (1) of a vibrating body showing an embodiment of the invention, and Fig. 3 is an embodiment of the present invention. FIG. 4 is a partial plan view of a vibrating body showing an example, FIG. 4 is a magnet for a moving body showing an embodiment of the present invention, and FIG. FIG. 6 is a perspective view of a moving body showing another embodiment of the present invention, and FIG. 7 is a sectional view of a vibrating body and a moving body showing another embodiment of the present invention. 1... Permanent magnet 2... Non-magnetic ring plate 3... Permanent magnet cutout 4... Vibrating body 5... Hall element 6... Electrostrictive element 7... Lead 8 ...Plastic magnet 9...Coil wire 1O...Square magnet or more Applicant: Seiko Electronic Industries Co., Ltd. Agent: Patent attorney: Tsutomu Mogami (and 1 other person) Figure 1 Partial rainbow view of the VJ cup (1) ) Figure 2 JP-A-1 magnet 1. Fig. 4 'Fr#tf14-24+-#vrmOko (2) Fig. 5 Fig. 6'

Claims (9)

[Claims] (1) In a wave motor that applies a frequency voltage to an electrostrictive element and drives a moving body connected to the vibrating body by progressive waves generated in a vibrating body connected to the electrostrictive element, a part of the moving body 1. A structure of a wave motor, characterized in that a permanent magnet is disposed, and a magnetic detection element is disposed in a part of the tooth part of a vibrating body, which has a tooth part whose contact part with a moving body is divided. (2) The structure of the wave motor according to claim 1, wherein the moving body is formed by joining a non-magnetic thin plate and a ring-shaped magnet with a partially cutout. (3) The structure of a wave motor according to claim 1, wherein the moving body is formed by joining ring-shaped magnets having N and S poles alternately polarized to a non-magnetic thin plate. (4) The structure of the wave motor according to claim 1, wherein a part of the inner periphery of the upper surface of the tooth portion of the vibrating body is provided with a cutout portion to accommodate a Hall element. (5) The structure of the wave motor according to claim 4, wherein the upper surface of the Hall element is concave than the upper surface of the teeth of the vibrating body. (6) The structure of the wave motor according to claim 1, wherein the vibrating body is made of a magnetic material with high magnetic permeability, and a coil is wound around a part of the teeth. (7) The structure of the wave motor according to claim 6, wherein a recess is provided in a part of the teeth of the vibrating body, and a coil is wound around the recess. (8) The structure of the wave motor according to claim 7, wherein the recessed portion of the tooth of the vibrating body is arranged downward from the central axis of the height of the tooth. (9) The movable body has a permanent magnet arranged on a non-magnetic thin plate, and the length of the permanent magnet in the magnetization direction is approximately equal to the pitch length of the divided teeth of the vibrating body. Structure of wave motor.