JPS627769B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electric-to-drive force converter that operates linearly, and aims to reduce the size and power consumption.

Conventionally, most electric-drive force converters (hereinafter referred to as linear actuators) that operate linearly and are used in small devices such as small tape recorders are plunger solenoids.

The plunger solenoid does not have any magnetic circuit including a permanent magnet as a driving source, and generates driving force using only the magnetic field generated by energizing the coil, so it consumes a large amount of power and requires a battery as a power source. Not only does this shorten battery life in devices that require large driving force, but the current consumption must also increase when large driving forces are required, forcing the overall size to become larger, making it difficult to incorporate it into smaller devices. I can't.

Also, it is impossible to perform bidirectional drive with a single plunger solenoid, so two plunger solenoids are required to perform bidirectional drive, and the size of small equipment is larger than that of a plunger solenoid. It was supposed to be restricted.

Furthermore, due to its operating principle, plunger solenoids not only cannot have long strokes, but also have iron cores that collide with each other and generate loud noises.Additionally, if soundproofing is applied to prevent this noise, the driving force will be reduced. It has many drawbacks such as being weak.

The present invention solves the above-mentioned drawbacks by generating driving force using a magnetic circuit using permanent magnets and a coil installed perpendicular to the magnetic field of the magnetic circuit.

In other words, the magnetic field of a magnetic circuit using permanent magnets and the current flowing through the coil cause a force to act in a direction perpendicular to the direction of the magnetic field and the current, as per Fleming's left-hand rule, and this force acts as a linear actuator. Bidirectional drive is possible by changing the direction of the current flowing through the coil.

The principle is the same as the voice coil section of a speaker, but the present invention focuses on extracting driving force as a linear actuator.
By making the magnetic circuit into a rectangular shape, the magnetic flux density in the gap in the magnetic path is increased, and a large force is extracted by the interaction between the magnetic force of the magnetic circuit and the magnetic force generated by energizing the coil. I'm trying to get it. Therefore, it is possible to generate large driving force even with small power consumption.

In addition, if a coil exists in the gap of the magnetic circuit, it will generate a constant driving force, so if you use a coil that is longer than the gap by the length of the stroke, the Not only does it always generate a constant force, so the length of the stroke can be freely selected, but by using a coil with a coil section longer than the air gap, the loss due to the coil increases, but the current value Therefore, the magnetic flux in the gap can be used most effectively.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The linear actuator of the present invention will be described in detail below with reference to the accompanying drawings showing one embodiment.

As shown in FIGS. 1 to 3, the linear actuator of the present invention includes a magnetic circuit consisting of a center pole 1, a yoke 2, a permanent magnet 3 fixed to the yoke 2, a bobbin 4, and a magnetic circuit wound around the bobbin 4. and an actuating section consisting of a coil 5.

The yoke 2 includes a substantially rectangular substrate 2' to which a center pole 1 having a rectangular cross-sectional shape is fixed, and side plates 2'' extending from the four edges of the substrate 2' in a direction parallel to the center pole 1. It consists of

Note that the adjacent side plates 2'' are not in direct contact with each other but are spaced apart from each other.

Plate-shaped permanent magnets 3 are provided at predetermined positions on the opposing inner surfaces of the side plates 2'', and the polarities of the opposing surfaces of the permanent magnets 3 are opposite to each other.

Therefore, the inner surface of the permanent magnet 3 and the outer surface of the center pole 1 facing the permanent magnet 3 are parallel to each other, and the magnetic flux density within the gap formed between the permanent magnet 3 and the center pole 1 can be increased.

Since there is always a magnetic field in a fixed direction between the permanent magnet 3 and the center pole 1, when the coil 5 is energized, the coil 5 moves in one direction due to the interaction between the magnetic field and the magnetic field generated by the coil 5. A driving force is applied to it, and it moves in one direction together with the bobbin 4. If the current is applied in the opposite direction, the direction of the magnetic field generated by the coil 5 will be reversed, so that the coil 5 will be moved in the opposite direction.

Note that, as shown in the center longitudinal sectional plan view of FIG. 1 and the center longitudinal sectional side view of FIG. It is in contact with the outer surface of pole 1. With this configuration, the actuating part is supported by the center pole 1 in a stationary state, while sliding along the outer surface of the center pole 1 in an actuated state.

Furthermore, since the magnetic field in the air gap directly acts on the coil located in the air gap and generates a driving force, if the length of the coil is determined according to the stroke, it will be as shown in the solid line in Figure 4. The same driving force can always be generated within a determined stroke, and it is possible to eliminate the drawback that the driving force suddenly decreases as the stroke increases, as in the plunger solenoid shown by the broken line in the figure.

In the figure, 6 is a connecting portion that connects the driven object and the bobbin 4, and 7 is a connecting hole.

The electricity-driving force converter of the present invention as described above has the following effects.

Since it is composed of a magnetic circuit including a permanent magnet and a coil, bidirectional driving is possible depending on the direction of energization to the coil.

Since the yoke and center pole have a rectangular cross section, the magnetic flux in the gap can be effectively used when downsized, and a large driving force can be obtained.

Incidentally, if the yoke and center pole were made cylindrical, it was not possible to obtain a large driving force when the yoke and center pole were incorporated into equipment such as a small tape recorder. This is because in order to obtain a large driving force, it is necessary to increase the depth of the yoke and center pole in order to generate a large magnetic flux in the air gap. However, in this case, the magnetic flux concentrated at the center pole becomes saturated, and therefore it is not possible to generate a large magnetic flux in the air gap. On the other hand, when the yoke and center pole have a rectangular cross section, when incorporated into the above-mentioned equipment, it is easy to incorporate the yoke and center pole into a small equipment by simply widening the width to an appropriate extent while keeping the depth of the yoke and center pole. By reducing the depth, saturation due to concentration of magnetic flux on the center pole can be avoided, so a large magnetic flux can be generated in the air gap, and a large driving force can thereby be obtained.

The same driving force can always be generated within the stroke range determined by the length of the coil.

Since the yoke and center pole have a rectangular cross section, it is easy to process the permanent magnet, and space can be used effectively, especially in small equipment.

Since the inner surface of the bobbin with the coil wound thereon is in contact with the center pole on all four sides, the operating section can be supported by the center pole, which simplifies the support structure of the operating section and improves the transmission of driving force. becomes good. In this case, it is extremely important that the center pole has a rectangular cross-sectional shape. If the cross-sectional shape of the center pole is circular, if the driven object connected through the connecting part is likely to generate rotational moment, the bobbin around which the coil is wound will easily rotate due to that rotational moment. As a result, stable reciprocating motion cannot be achieved. On the other hand, if the center pole has a rectangular cross-sectional shape as in the present invention, it is possible to prevent the above-mentioned careless rotational movement and to stably realize accurate reciprocating movement.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG.
The figure is a side view of the central longitudinal section, Figure 3 is a front view of the same, and Figure 4 is a front view of the same.
The figure shows the stroke-driving force characteristics. 1...Center pole, 2...Yoke, 3...Permanent magnet, 4...Bobbin, 5...Coil.

Claims (1)

[Claims] 1. A plate-shaped permanent magnet is fixed on four sides of the inner surface of a yoke whose internal space has a square cross section, and a center pole with a square cross section is fixedly arranged in the center of the internal space of the yoke, and the center pole and the A bobbin with a coil wound between plate-shaped permanent magnets,
The bobbin is slidably installed with four inner surfaces in contact with the center pole, and the bobbin can be driven in both directions by changing the direction of energization to the coil. Electricity-driving force converter.