JPH08331828A - Linear vibrating motor - Google Patents

Abstract

PURPOSE: To enable a linear vibrating motor to make smooth reciprocating vibrations with small driving energy. CONSTITUTION: A linear vibrating motor is constituted of a stator 1 composed of an electromagnet or permanent magnet, a mover 2 which is provided with a permanent magnet or electromagnet and supported by springs, a detecting means which detects the moving direction of the mover 2 when the mover 2 makes reciprocating vibrations, and a control means which controls the direction of the electric current supplied to the coil 11 of the electromagnet in accordance with the output of the detecting means. Therefore, the occurrence of such a case that the vibrations of the mover 2 is braked by giving a driving force to the mover 2 while the mover 2 makes vibrations can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linear vibration motor which causes a linear motor to reciprocate.

[0002]

2. Description of the Related Art JP-A-2-52692 discloses that a linear motor is used as a source of reciprocating vibration. This linear vibration motor used as a drive source of a reciprocating electric shaver has a mover made of a rod-shaped permanent magnet, and a U
It is formed as a single-phase synchronous motor consisting of a stator with a coil wound around each piece of a U-shaped iron core, and a full-wave rectifier circuit supplies a DC voltage of twice the AC frequency to the coil. The mover is reciprocating.

[0003]

In this case, a strong electromagnetic force is required to reciprocate the mover to generate vibration, but the mover is supported by a spring to constitute a spring vibration system. If the driving is performed in synchronization with the natural frequency of the spring vibration system, the energy required for driving can be reduced.

However, when such driving is performed,
When a temporary stop occurs due to an overload or the like, the moving direction of the mover may deviate from the driving direction, and smooth driving may not be possible. The present invention was invented in view of the problems of the above-mentioned conventional example, and the purpose thereof is to:
It is an object of the present invention to provide a linear vibration motor that can obtain a smooth reciprocating vibration while requiring a small driving energy.

[0005]

SUMMARY OF THE INVENTION The linear vibration motor according to the present invention, however, includes a stator composed of an electromagnet or a permanent magnet, a mover having the permanent magnet or the electromagnet and spring-supported, and a reciprocating motion of the mover. It is characterized in that it comprises a moving direction detection means for vibration and a control means for controlling the direction of current supplied to the coil in accordance with the output of the detection means.

[0006]

According to the present invention, it is possible to prevent a situation in which a driving force is applied to a moving movable element in the wrong direction to brake the vibration.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the embodiments shown in the accompanying drawings. First, an example of the structure of the linear vibration motor will be described. FIGS. 4 and 5 show a linear vibration motor for a reciprocating electric shaver, which includes a stator 1 and a mover 2 (two movers 21 in the figure). , 22) and a frame 3.

The stator 1 includes an E-shaped yoke 10 in which a sintered body of a magnetic material or an iron plate of a magnetic material is laminated, and this yoke 10.
The coil 11 is wound around the central piece of the above, and pins 12 are provided so as to project from both end surfaces of the yoke 10. The frame 3 to which the stator 1 is fixed has a bottom plate 31, 31 between the lower parts of the ends of the pair of side plates 30, 30, respectively.
The stator 1 has its pins 12 fitted in fixing grooves 32 formed in the side plate 30 and fixed to the frame 3 by welding or caulking.

As shown in FIG. 5, each of the two types of movers 21 and 22 has a reinforcing plate 25 made of a non-magnetic metal plate and a back yoke 26 on the lower surface of the driven bodies 23, 23 made of synthetic resin. The permanent magnet 20 is fixed to the driven body 23 of the mover 21 in a planar shape in a square shape, and the reinforcing plate 25, the back yoke 26, and the permanent magnet 2 are provided.
0 is provided on each lower surface of both side pieces of the driven body 23,
Further, the reinforcing plates 25 on both sides are integrally formed.
The reinforcing plate 25 is integrated with the driven body 23 by insert molding (outsert molding). Reference numeral 24 in the drawing denotes a connecting portion which is integrally provided on the driven body 23 and to which the inner blade of the reciprocating electric shaver is connected.

Both ends of the movers 21 and 22 are connected to the frame 3 via leaf springs 4 and 4. The leaf spring 4 here is formed by punching from the metal plate 4 ', and the support plate 40 is attached to the fixed portion to the frame 3 and the connecting plate 43 is attached to the fixed portion to the movers 21 and 22, respectively. The central plate spring part 41 connected to the mover 22 and the pair of left and right plate spring parts 42, 42 connected to the mover 21 are integrally connected at the support plate 40. 40 is fixed to both ends of the frame 3 by means such as welding, and each connecting plate 43 is attached to the mover 2
When fixed to the end portions of the reinforcing plates 25 of the Nos. 1 and 22 by means such as welding, both the movers 21 and 22 are suspended from the frame 3, and are placed inside the mover 21 having a square shape in plan view. The connecting portion 24 of the mover 22 is located. Also,
Between the spring bearing portions 26, 26 on the inner surface of the mover 21 and the spring bearing portions 27, 27 of the connecting portion 24 of the mover 22, a pair of compression coil springs are formed in the reciprocating direction of the movers 21, 22. Spring members 28, 28 are provided.

In the linear vibration motor constructed as described above, the permanent magnet 20 provided on the mover 2 is vertically opposed to the stator 1 with a predetermined gap, and the reciprocating direction of the mover 2 is increased and decreased. As shown in FIG. 2, the plate spring 4 is bent while moving to the left and right in accordance with the direction of the current flowing through the coil 11 of the stator 1, as shown in FIG. By switching the direction at an appropriate timing, the mover 2 can be caused to perform reciprocating vibration.

Further, here, the arrangement of the magnetic poles of the permanent magnets 20 provided on the mover 21 and the permanent magnets 2 provided on the mover 22.
Since the arrangement of the magnetic poles of 0 is reversed, both movers 2
1 and 22 perform reciprocating vibrations whose phases are different by 180 °. At this time, since the spring members 28, 28 are compressed and expanded, the spring system shown in FIG. 2 is constituted by the leaf spring 4 and the spring member 28 (strictly, a spring constant component due to the magnetic attraction force is further added). ing.

When vibrating a vibrating system having such a spring system, it is necessary to vibrate in synchronization with the natural frequency of the vibrating system, that is, to bring it into a resonance state in order to realize stable vibration. Since it is preferable in terms of reduction of driving energy, in order to perform such driving, power supply to the coil 11 is performed for a predetermined time T while switching the current direction at predetermined intervals t0 that match the natural frequency. In this example, the sensing magnet 29 is attached to the mover 21, and the sensor 39 including the sensing winding shown in FIG. It is assumed that the control output unit 5 controls the current flowing through the coil 11 based on the current (voltage) induced in the sensor 39 with the vibration of the child 21. There. In the illustrated example, the drive current amount is controlled by PWM control, and the current amount is gradually increased within the energization time.

That is, the voltage of the current induced in the sensor 39 changes according to the magnitude and position of the amplitude of the mover 2, the speed of vibration, the direction of vibration, etc., as shown in FIG.
That is, when the mover 2 reaches one end of the amplitude of its reciprocating motion, the movement of the magnet 29 stops and the change in the magnetic flux disappears, and the output of the sensor 39 becomes zero. The speed of No. 2 becomes maximum and the output voltage of the sensor 39 also becomes maximum. Since the direction in which the current flows changes depending on whether the moving direction of the mover 2 (magnet 29) is reciprocating, the mover 2 is in either moving direction of reciprocating depending on the polarity of the output voltage. Can be detected.

Based on the determination of the moving direction, the control output unit controls the direction of the current supplied to the coil 11 so that the driving force acts in the direction in which the mover 2 is currently moving. Therefore, a situation in which the drive current becomes a brake does not occur, and even if a temporary stop occurs due to an overload, the current can flow in an appropriate direction. Therefore, reliable driving can be performed. Note that if the natural frequency fluctuates due to deterioration over time and you try to drive at a constant frequency, the output timing will not match and you will be driven with the amplitude decreasing or you will become a brake and lose energy. Therefore, it is preferable to stop the output when the timing does not match.

As the detecting means, the combination of the sensing magnet 29 and the sensor 39 composed of a winding wire is used in the above embodiment, but it is not limited to this. For example, a combination of the sensing magnet 29 and the sensor 39 including a magnetic sensitive element, the slit plate 60 and the optical detecting element 38 shown in the embodiments of FIGS. 4 and 5 can be used. However, a non-contact type that does not interfere with the vibration of the mover 2 is preferable.

If the load fluctuation is large and the amplitude of the reciprocating vibration is likely to change due to this, the detecting means for detecting at least one of the displacement, speed and acceleration of the mover 2 and the mover 2 will be described. It is also possible to provide the detection means for detecting the reversal time point of the moving direction and control the amount of electric power supplied to the coil 11 and the energization start timing t in accordance with the output of these detection means. Even if the amplitude changes for some reason, the amplitude change can be detected, and the power supply according to the amplitude change (for example, energization time T
Adjustment), the amplitude can be made constant, and even when the natural frequency is constantly changed due to a change with time or the like, the power can be supplied at the timing t according to the change.
It will not cause energy loss.

[0018]

As described above, according to the present invention, in order to control the direction of the current supplied to the coil in accordance with the output of the detecting means for the moving direction in the reciprocating vibration of the mover, the moving mover is vibrated. It is possible to prevent a situation in which a driving force is applied in the wrong direction and the vibration is braked, and it is possible to stabilize the vibration and save power.

[Brief description of drawings]

FIG. 1 is a time chart showing the operation of an embodiment of the present invention.

FIG. 2 is a schematic view of the above.

FIG. 3 is a block diagram of the above.

FIG. 4 is an exploded perspective view of the above specific example.

FIG. 5 is an exploded perspective view of the mover of the above.

[Explanation of symbols]

 1 Stator 2 Movable Element 3 Frame 5 Control Output Section 11 Coil 39 Sensor

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Ude Claude France 25000 Besancon 78 Avenue Clemenceau Moving Magnet Technologies Society of Anonymous (72) Inventor Prudham Daniel France 25000 Besancon 78 Avenue Clemenceau Moving Magnet Technologies Societe Within anonym

Claims (1)

[Claims] 1. A stator comprising an electromagnet or a permanent magnet,
From a mover that is provided with a permanent magnet or an electromagnet and is spring-supported, a moving direction detection unit for reciprocating vibration of the mover, and a control unit that controls the direction of the current supplied to the coil according to the output of the detection unit. A linear vibration motor characterized by the following.