JPH0727825Y2 - Linear generator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial field of application) The present invention makes it possible to obtain a voltage proportional to the speed of a mover and to reduce iron loss to obtain high efficiency. With respect to linear generators, it is used as a generator and speed sensor for free piston Stirling engines.

(Prior Art) As described in U.S. Pat. No. 4,602,174, a conventional linear generator is a cylindrical permanent magnet movable generator, in which a cylindrical radially magnetized magnet is made of a highly magnetically permeable material. A free piston Stirling engine reciprocates on the outer or inner circumference of a coil wound around an iron core to change the number of magnetic fluxes linked to the coil to generate electricity.

(Problems to be Solved by the Invention) However, in the above-described conventional linear generator, since the coil is wound so as to be orthogonal to the movement direction of the permanent magnet and the linear generator is formed in a cylindrical shape, Is very difficult to stack, and the iron loss cannot be reduced, and high efficiency cannot be obtained. Further, it is difficult to manufacture a cylindrical magnet, and therefore, if the magnet is divided into four parts, the accuracy cannot be obtained, the air gear cup cannot be shortened, and the efficiency is reduced.

These problems can be solved if the coil is wound in parallel with the movement direction of the permanent magnet to form the linear generator in a flat plate shape, but if the shape is changed from a cylindrical shape to a flat shape, the magnetic attraction force by the permanent magnet is increased. Therefore, the load of the bearing increases and the life of the bearing decreases.

Therefore, the present invention optimizes the method of arranging the permanent magnets to eliminate the generation of magnetic attraction force and reduce the iron loss by reducing the iron loss by making the shape of the linear generator flat without reducing the durability of the bearing. That is the technical problem.

[Structure of Invention]

(Means for Solving the Problem) The technical means taken for solving the above-mentioned technical problem is that the configuration of the linear generator is magnetized in a direction orthogonal to its movement direction and is reversed by adjacent comrades. A mover composed of a plurality of flat permanent magnets having polarities, an iron core arranged on both sides of the mover with a gap in the magnetizing direction, and an iron core and the iron core. A stator composed of a coil wound in the moving direction of the mover,
The direction of the magnetic flux passing through the mover is orthogonal to the moving direction of the mover.

(Operation) The magnetic path of the magnetic flux generated from the permanent magnet changes due to the relative displacement between the mover and the stator, the amount of magnetic flux linked to the coil changes, and voltage is induced in the coil to generate electricity. At this time, since the direction of the magnetic flux passing through the permanent magnet is only the direction orthogonal to the movement direction, the magnetic flux density in the gap between the permanent magnet and each stator becomes the same, and the generation of magnetic attraction force can be eliminated. ,
As a result, the durability of the bearing is not reduced, and the linear generator is shaped like a flat plate to reduce iron loss and obtain high efficiency.

(Example) Hereinafter, one example of the linear generator according to the present invention will be described with reference to the drawings.

In FIG. 1, two flat plate-shaped permanent magnets 1, which are movable elements in the present invention, are attached to a shaft (not shown) that is coupled to a reciprocating rod of a Stirling engine (not shown) and is supported by a holder (not shown) via a bearing. 2, the magnetizing directions are perpendicular to the movement direction (direction B in FIG. 1) and the polarities of the magnets are opposite to each other, and the magnets 2 are arranged side by side and fixed. Stator cores 3 and 4 are arranged on both sides of the permanent magnets 1 and 2 on the magnetization direction side. The stator cores 3 and 4 are formed by laminating thin steel plates having high saturation magnetic flux density and have an E shape.
Coils 5 and 6 are wound around the stator cores 3 and 4 in parallel with the moving directions of the permanent magnets 1 and 2, respectively, as shown in FIG. The stator cores 3 and 4 and the coils 5 and 6 form the stator in the present invention. Incidentally, FIG. 3 shows an external view of the linear generator in this embodiment.

The stator cores 3 and 4 are arranged so that their E-shaped opening sides are opposed to each other, and magnetic poles 7 and 8 are respectively provided between the permanent magnets 1 and 2 on their opposing surfaces so as to be separated from each other. 10 are formed integrally with each other. The gap L between the magnetic poles 7 is made as small as possible, and the permanent magnets are always attached to the magnetic poles 7 and 8.
The magnetic resistance between the permanent magnets 1 and 2 and the magnetic pole 7 is made constant by making 1 and 2 face each other, and the change of the magnetic energy stored in the air gears 9 and 10 is made small, and the cogging, which is the thrust when no load is applied. The power is reduced.

The operation of this embodiment having the above configuration will be described.

In FIG. 1, the permanent magnets 1 and 2 reciprocate in the B direction from end to end of the stator cores 3 and 4 by the rod of a Stirling engine (not shown), and the magnetic flux generated from the permanent magnets 1 and 2 is thereby generated. The magnetic path of Φ changes due to the relative displacement between the mover and the stator, the amount of magnetic flux linked to the coils 5 and 6 changes, and voltage is induced in the coils 5 and 6 to generate electricity.

Generally, when the linear generator has a flat plate structure, it is easier to stack the stator cores and the iron loss can be reduced as compared with the cylindrical shape, but a large magnetic attraction force is generated by the permanent magnets, and a large magnetic force is generated. Bearing load will result in bearing loss and deteriorate durability. In this embodiment, the mover and the stator are arranged so that the direction of the magnetic flux passing through the mover, that is, the permanent magnets 1 and 2 is only the direction orthogonal to the movement direction of the permanent magnets 1 and 2. There is. Therefore, in FIG. 1, the magnetic flux Φ in the linear generator is a magnetic path that passes through the stator core 3, the permanent magnet 2, the stator core 4, the permanent magnet 1, and returns to the stator core 3. Even if the permanent magnets 1 and 2 are misaligned or the air gears 9 and 10 are different, the magnetic flux densities of the air gears 9 and 10 have the same value, and no magnetic attraction force is generated.

The gap L between the magnetic poles 7 is made as small as possible to reduce the cogging force as described above, and the permanent magnets 1 and 2 are always opposed to each other in the reciprocating motion of the permanent magnets 1 and 2. Since the operating points of the permanent magnets 1 and 2 are constant and the magnetic flux densities of the air gear cups 9 and 10 are constant, there is no fluctuation in the magnetic attraction force and fluctuations in the load, and the durability of the bearing can be improved.

Further, in this embodiment, since the entire surface of the mover is a magnet, the output per mass of the mover can be increased, and
Since the mover does not require an iron core, inertial force during movement can be reduced.

FIG. 4 shows another example of the mover of the present invention, and shows the mover structure in the case where the iron core is not required in the mover for reasons such as mounting of bearings. In this example, the flat permanent magnet 2
The magnets 0, 21 are arranged side by side so that their magnetizing directions are perpendicular to the movement direction (direction B in the figure) and the polarities of the magnets are opposite, and the plate-shaped permanent magnets 22, 23 are also magnetized. The magnetic direction is perpendicular to the movement direction (B direction in the figure) and the polarities of the magnets are opposite to each other, and the iron cores 24, 25 are arranged between the permanent magnets 20, 21 and 22, 23 of each set. It is held. The iron cores 24, 25 are divided by the non-magnetic body 26 at the adjacent points of the adjacent permanent magnets 20, 21 and 22, 23, so that the magnetic flux Φ ₁ of the permanent magnets does not flow in the movement direction, All flow in the direction orthogonal to the movement direction, and prevent the generation of magnetic attraction force.

〔The invention's effect〕

According to the present invention, since a voltage proportional to the speed of the mover can be obtained, a generator can be used as the speed sensor.

According to the present invention, the permanent magnets are arranged only in the direction in which the magnetic flux passing through the permanent magnets is orthogonal to the movement direction, and the magnetic flux density in the gap between the permanent magnets and each stator is optimized. It is possible to eliminate the generation of the magnetic attraction force, and thereby the durability of the bearing is not lowered, and the linear generator can be formed in a flat plate shape to reduce iron loss and obtain high efficiency.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a linear generator according to the present invention, FIG. 2 is a view taken in the direction of arrow A in FIG. 1, and FIG. 3 is an external view of the embodiment shown in FIG. FIG. 4 is a sectional view showing another example of the mover according to the present invention. 1,2 …… Permanent magnet, 3, 4 …… Stator core, 5, 6 …… Coil, 7,8 …… Magnetic pole, 9, 10 …… Air gear cup, 20, 21, 22, 23
...... Permanent magnet, 24,25 …… Iron core, 26 …… Non-magnetic material.

Claims (2)

[Scope of utility model registration request] 1. A mover composed of a plurality of flat plate-shaped permanent magnets which are magnetized in a direction orthogonal to the direction of movement and are adjacent to each other and have opposite polarities, and the permanent magnets on both sides of the mover. An iron core arranged so as to sandwich the magnet in the magnetizing direction, and a stator composed of a coil wound around the iron core in the moving direction of the mover, and the direction of the magnetic flux passing through the mover is A linear generator that is orthogonal to the moving direction of the mover. 2. The movable element is composed of a plurality of flat plate-shaped permanent magnets that hold an iron core in a magnetizing direction, and the iron core is divided by a non-magnetic material at a point adjacent to the permanent magnet. The linear generator described in 1).