JPH0617377U - coil - Google Patents

Abstract

(57) [Summary] [Purpose] To shorten the rise time in the coil and speed up the response time. [Structure] The linear motor coil has a structure in which a primary coil 16a and a secondary coil 16b formed coaxially outside the primary coil 16a are connected in parallel. Primary coil 16a
The secondary coil 16b applies the current in the opposite direction with the same winding direction, or applies the current in the same direction with the opposite winding direction. [Effect] Since the magnetic flux generated by the mutual inductance is canceled out, the combined self-inductance of the primary coil 16a and the secondary coil 16b can be reduced.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a coil, and particularly to a coil having a small inductance and capable of shortening the rise time of the linear motor coil when used in a coil for a linear motor.

[0002]

[Prior art]

 2. Description of the Related Art Conventionally, there is a vibration isolation table for insulating mounted equipment from vibration transmitted from the floor or the like. The anti-vibration table actively reduces the vibration of the floor via an air spring and the like, and at the same time, detects the vibration with a sensor and applies a force to cancel the vibration to actively remove the vibration. As a device for actively removing vibration, there is a linear motor that electrically applies a load to the vibration isolation table by a signal from a sensor.

A linear motor uses a repulsive force between a permanent magnet and a coil, and its operating amount is variable depending on the current supplied to the coil, and controls the vibration of a vibration isolation table.

[0004]

[Issues to be solved by the device]

 As shown in FIG. 2, such a linear motor 1 includes a rear yoke 2 having an iron bottom surface 2a and columns 2b perpendicular to the bottom surface 2a, and a bottom surface 2a of the rear yoke 2 which is perpendicular to the circumference of the bottom surface 2a. The side yoke 3 made of iron to be bonded, the pillar 2b of the rear yoke 2 joined to the inside of the side yoke 3 and the permanent magnet 5 provided with a gap 4 are integrally formed, and the coil 6 is vertically arranged in the gap 4. It is movably inserted. The amount of vertical movement of the coil 6 is determined by the current supplied to the coil 6, and the vibration isolation table is loaded.

Here, when the current flowing through the coil changes during the time t, the magnetic flux changes due to this current, and an electromotive force is induced in the direction in which the change in the magnetic flux is hindered. So-called self-induction (self-inductance) occurs. If the permeability of the surrounding material is constant, the change in magnetic flux is proportional to the change in current, and the change in electromotive force per unit time is proportional to the change in current flowing in the coil. The self-inductance is represented by the proportional constant at this time, that is, the magnitude of the self-inductance coefficient (self-induction coefficient).

However, the conventional coil is composed of one coil 6 as shown in FIG. 3, and accordingly, in the linear motor in which the current flowing with the change of the vibration constantly changes in order to control the vibration, Research has been conducted to reduce the self-inductance by suppressing the generation of electromotive force that interferes with the change in current, and to shorten the rise time to speed up the response time of the linear motor, but there was a limit.

An object of the present invention is to provide a coil that can reduce the inductance and suppress the generation of electromotive force that hinders the change of the current of the coil.

[0008]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, the coil of the present invention is a coil consisting of at least two in which an opening is provided at the center, the primary coil is coaxially located inside, and the secondary coil is arranged outside the primary coil. Then, the windings of the primary coil and the secondary coil are made to have the same winding direction and currents in opposite directions are applied, or the windings of the primary coil and the secondary coil are applied. The current is applied in the same direction, with the winding directions of and being opposite.

[0009]

[Action]

 A secondary coil is formed coaxially with the primary coil and outside the primary coil. Mutual induction (mutual inductance) that induces electromotive force in the other coil is generated by the current flowing in one coil when multiple coils are brought close to each other, but the primary coil and the secondary coil are provided coaxially, If the magnetic fluxes generated in both coils are connected in opposite directions, the mutual magnetic flux can be reduced. Moreover, by providing both coils in parallel, the inductance can be reduced even if the total number of turns of the plurality of coils is the same as the number of turns when the number of coils is one. When such a coil is used in a linear motor, mutual inductance can be reduced, generation of electromotive force that hinders changes in coil current can be suppressed, and the startup time of the linear motor can be shortened.

[0010]

【Example】

 An embodiment in which the coil of the present invention is applied to a linear motor will be described with reference to the drawings. As shown in FIG. 1, the linear motor coil 16 of the present invention is a coil used in a linear motor similar to the linear motor 1 shown in FIG. That is, the rear yoke 2 including the bottom surface 2a and the pillars 2b that are iron cores that are vertically provided on the bottom surface 2a, the side yoke 3 that is vertically provided on the circumference of the bottom surface 2a of the rear yoke 2, and the inside of the side yoke 3. A permanent magnet 5 which is joined to the support column 2b of the rear yoke 2 and has a gap 4 is integrated, and a coil 16 is loosely inserted in the gap 4 to form a linear motor. Is.

The coil 16 is composed of a primary coil 16a formed by providing an opening 40 in the center and a secondary coil 16b coaxially formed outside the primary coil 16a. The primary coil 16a and the secondary coil 16a have approximately the same number of turns, and the primary coil 16a and the secondary coil 16b are connected so that the magnetic fluxes generated in the primary coil 16a and the secondary coil 16b are in mutually opposite directions. 16b are provided in parallel.

In order for the magnetic fluxes generated in the primary coil 16a and the secondary coil 16b to be in mutually opposite directions, the winding directions of the primary coil 16a and the secondary coil 16b should be the same, and the primary coil 16a 17a and the end 18b of the secondary coil 16b, the end 17b of the primary coil 16a and the start end 18a of the secondary coil 16b are mutually connected, or the primary coil 16a and the secondary coil 16b are wound. The directions are reversed, and the starting end 17a of the primary coil 16a, the starting end 18a of the secondary coil 16a, the end 17b of the primary coil 16a, and the end 18b of the secondary coil 16b are connected to each other. By making such a connection, the directions of the magnetic flux generated in the primary coil 16a and the secondary coil 16b can be reversed.

The primary coil 16a and the secondary coil 16b thus connected are coaxially wound, and the magnetic flux generated by the current of one coil is linked with the other coil. Here, assuming that the number of turns of the two coils provided coaxially, the primary coil 16a and the secondary coil 16b is N ₁ and N ₂ , respectively, and there is no leakage magnetic flux, the magnetic flux generated by the current of one coil is the other. Since it is linked to the coil of the primary coil 16a, the magnetic flux when an invariant current is applied to the primary coil 16a is φ ₁ , the self-inductance of the primary coil 16a is L ₁ , Let M be the mutual inductance of L ₁ = N ₁ φ ₁ M = N ₂ φ ₁ = (N ₂ / N ₁ ) L ₁ (Equation 1).

Similarly, assuming that the magnetic flux generated when an invariable current flows through the secondary coil 16b is φ ₂ and the self-inductance of the secondary coil 16b is L ₂ , L ₂ = N ₂ φ ₂ M = N ₁ φ ₂ = (N ₁ / N ₂ ) L ₂ (Equation 2).

When such a primary coil 16a and a secondary coil 16b are connected in parallel so that mutual magnetic fluxes are in opposite directions, and an invariable current is flown, the primary coil 16a and the secondary coil 16b are generated. Letting the magnetic fluxes be φ ₁ and φ ₂ , respectively, they all interlink with both coils, and if the combined self-inductance of the primary coil 16a and the secondary coil 16b is L ₁ ′ and L ₂ ′, then L ₁ ′ = N ₁ (φ ₁ −φ ₂ ) L ₂ ′ = N ₂ (φ ₂ −φ ₁ ), where N ₁ φ ₁ = L ₁ , N ₂ φ ₂ = L ₂ N ₁ φ ₂ = M, From N ₂ φ ₁ = M, L ₁ ′ = L ₁ −M L ₂ ′ = L ₂ −M.

Since the primary coil 16a and the secondary coil 16b are in parallel, the combined self-inductance L _{12 at} the terminals of the primary coil 16a and the secondary coil 16b is 1 / L ₁₂ = (1 / L ₁ ′) + _{(1 / L 2 ') =} (1 / L 1 -M) + (1 / L 2 -M) next, L ₁ ≒ L ₂ from the number of turns N ₁ ≒ N ₂ for now the primary coil 16a and the secondary coil 16b And the relationship of 1 / L ₁₂ ≈2 / L ₁ −M to L ₁₂ ≈ (L ₁ −M) / 2 holds. From Equation 1 and Equation 2, M ² = L ₁ L ₂ M = √ (L ₁ L ₂ ) and L ₁ ≈L ₂ , so M ≈L ₁ .

However, since there is actually a leakage magnetic flux, M = α√ (L ₁ L ₂ ) (0 ≦ α ≦ 1) M = αL ₁ L ₁₂ ≈ (1-α) L _1/2 , Since the combined self-inductance L ₁₂ can cancel the magnetic flux generated in the primary coil 16a and the secondary coil 16b, it can be made extremely small.

Considering the inductance composed of one coil, assuming that the total number of turns is 2N ₁ provided by dividing the number of turns into two coils and the change of the magnetic flux per unit current is φ ₃ , the inductance L ₃ is L ₃ = 2N ₁ φ ₃ . The change in magnetic flux φ ₃ is larger than the change in magnetic flux φ ₁ that occurs when the number of turns is N ₁ , and L ₃ = 2N ₁ φ ₃ > L ₁ = N ₁ φ ₁ . M≈L ₁ to L ₁ = N ₁ φ ₁ > L ₁₂ ≈ (L ₁ −M) / 2, and from the relationship of L ₃ > L ₁ > L ₁₂ , it is obvious that the number of turns is divided and the coils are provided in parallel. Greater inductance.

Therefore, when a coil having a small inductance is used in a linear motor, the rise time of the motor represented by t = R / L can be shortened. Therefore, it is possible to obtain a linear motor having a sharp response. The above description is an explanation of one embodiment, and the present invention is not limited to this, and may include not only two coils but also two or more coils. Further, not only a linear motor but also a coil having a small inductance and good responsiveness can be suitably used in any device.

[0020]

[Effect of device]

 As is clear from the above description, according to the coil of the present invention, the coil is divided and parallelized even with the same number of turns, so the inductance can be made extremely small by reducing the electromotive force due to the change in current. Therefore, a highly responsive coil can be obtained.

[Brief description of drawings]

FIG. 1 is a perspective view showing a coil for a linear motor according to an embodiment of the present invention.

FIG. 2 is a sectional view showing a linear motor in which the linear motor coil shown in FIG. 1 is used.

FIG. 3 is a perspective view showing a conventional linear motor coil.

[Explanation of symbols]

 16 ... coil for linear motor (coil) 16a ... primary coil 16b ... secondary coil 40 ... opening

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Creator Yasufumi Kamezawa 2-1-1 Oda Sakae, Kawasaki-ku, Kawasaki-shi, Kanagawa, Showa Electric Wire & Cable Co., Ltd. (72) Sukehiro Akama, Sakae Oda, Kawasaki-ku, Kawasaki-shi, Kanagawa No. 1-1 No. 1 Showa Electric Cable Co., Ltd.

Claims (1)

[Scope of utility model registration request] 1. A coil consisting of at least two in which an opening is provided at the center, a primary coil is coaxially located inside, and a secondary coil is arranged outside the primary coil. The wire and the winding of the secondary coil have the same winding direction, and currents of opposite directions are applied to each other, or the winding directions of the primary coil and the secondary coil are opposite to each other. A coil characterized by applying currents in the same direction.