JPH0623177Y2 - Electromagnetic drive - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to an electromagnetic drive device such as a voice coil motor and a bridge control motor.

(Prior Art) Conventionally, an electromagnetic drive device having a speed signal detection circuit as shown in FIG. 5 that does not use a speed detection coil is known from Japanese Patent Laid-Open No. 59-156139. 11 in the figure
Is a drive coil in an electromagnetic drive device such as a voice coil type motor or a cylindrical servomotor, and has an inductance L and a resistance R _{C. RS} is a drive current detection resistance connected in series with the drive coil 11, and R and C are drive output detection resistance and drive output detection connected in parallel with the drive coil 11 and the drive current detection resistance _RS. A condenser, 12 is an output circuit including a drive amplifier for driving and moving the drive coil 11, and 13 is an arithmetic circuit including an arithmetic unit.

In the speed signal detection circuit in this electromagnetic drive device, the input signal is amplified by the output circuit 12 and applied to the drive coil 11 via the drive current detection resistor R _S, and the drive output detection resistor R and the drive output detection capacitor C are connected. current of the drive coil 11 by the drive current detecting resistor R _S is detected is applied to the series circuit, the drive voltages across both ends of the driving output detection capacitor C of the drive current detection resistor R _S is compared computed by the computing circuit 13 The velocity signal of the coil 11 is detected. The speed signal of the drive coil 11 is the drive coil 1
The back electromotive force generated when 1 moves is detected.

Cutoff frequency _A of this speed signal detection circuit in the electromagnetic drive consists of a drive coil 11 a drive current detection resistor R _s L / R integration circuit Therefore, the cutoff frequency _B of the R / C integrating circuit including the drive output detection resistor R and the drive output detection capacitor C is _B 1 = 1 / 2πCR. R _C , R _S , L, C, and R are determined to have values such that _A = _B, and the variation of L, R _S , C, and R is small, but R _C is the resistance value of the drive coil 11. Normally, there is a large variation (+10 depending on the wire material and winding conditions).
%). Due to this variation, the variation of the cutoff frequency of the L / R integration circuit becomes large, and the arithmetic circuit 1
The S / N of the speed signal from 3 deteriorates.

Therefore, in the speed signal detection circuit of this electromagnetic drive device, as shown in FIG. 6, a minute resistance R _a for correction is inserted in series with the drive coil 11, and this correction resistance R _a and the resistance value R _{C of the} drive coil 11 are set. There has been proposed a method in which the variation of the cut-off frequency of the L / R integration circuit is reduced by setting the combined resistance value of 1 to a constant value. Here, the electromagnetic drive device is composed of, for example, a linear motor, and the drive coil 11 is wound around the drive coil bobbin 14. The drive coil bobbin 14 is provided so as to surround the inner yoke 15 and be movable in the axial direction thereof, and both ends of the inner yoke 15 are coupled to the outer yoke 16 to form a closed magnetic circuit. The permanent magnet 17 faces the outer peripheral surface of the outer yoke 16, and the drive coil 11 is driven by the output circuit 12 to move along the inner yoke 15. The main board 18 is a printed wiring board on which the output circuit 12, the drive output detection resistor R, the drive output detection capacitor C, and the arithmetic circuit 13 are printed. Based on the speed signal from the arithmetic circuit 13, the speed control circuit gives the output circuit 12 an input signal for moving the drive coil 11 at a predetermined speed. The drive current detection resistor R _S is wound around the drive coil 11 as a resistance wire that is folded back so that the generated magnetic fields cancel each other out, and the correction resistor R _a is mounted on the main substrate 18 that is separated from the drive coil bobbin 14.

In this electromagnetic drive device, the cutoff frequency _C of the L / R integration circuit is Therefore, the correction resistance R _a causes R _C + R _s + R _{a to} be substantially constant, so that the cutoff frequency of the L / R integration circuit is
The variation of _c can be reduced and the S / N of the speed signal from the arithmetic circuit 13 can be improved.

(Problems to be Solved by the Invention) In the electromagnetic drive device of FIG. 6, since the correction resistor _Ra is mounted on the main board 18 which is separate from the drive coil bobbin 14, the drive coil bobbin 14 and the main board 18 are separated from each other. It is necessary to assemble in a one-to-one correspondence, and the assembly workability and productivity are poor.

(Means for Solving Problems) The present invention is to connect a drive current detection resistor in series with a drive coil of an electromagnetic drive device and to provide a drive output detection resistor in parallel with the drive coil and the drive current detection resistor. In the electromagnetic drive device having a speed signal detection circuit in which a drive output detection capacitor and a drive output detection capacitor are connected in series, a correction resistor is connected in series to the drive coil, and the correction resistor is connected to the drive coil or the drive coil bobbin. It is attached so as to be integrated with.

(Function) The present invention detects the speed signal of the drive coil by comparing and calculating the voltage across the drive current detection resistor and the voltage across the drive output detection capacitor in the speed signal detection circuit.

(Embodiment) FIGS. 1 and 2 show a part of an embodiment of the present invention.

This embodiment eliminates the need for one-to-one correspondence of the assembling of the driving coil bobbin 14 and the main board 18 by forming a corrected resistance R _a together with the driving coil bobbin 14 in the electromagnetic driving device of the FIG. 6, the assembling workability, The productivity is improved, and the same parts as those in FIG. 6 are designated by the same reference numerals. The correction resistor R _a is printed on the correction resistor substrate 19 made of ceramic, and the correction resistor substrate 19 is integrally bonded to the drive coil bobbin 14. Both ends of the drive current detection resistor R _s are connected to pins 20 and 21 provided on the drive coil bobbin 14, and both ends of the drive coil 11 are connected to pins 22 and 23 provided on the drive coil bobbin 14. Correction resistor R _a
Both ends of the pin 2 are provided on the drive coil bobbin 14.
3, 24, while the main board 18 has pins 25
~ 28 are provided. The pin 25 is connected to the output terminal of the output circuit 12, and the pins 26 and 27 are connected to the inverting input terminal of the arithmetic circuit 13. The pin 28 is grounded, and both ends of the lead wire 29 are connected to the pins 20 and 27 by soldering. Both ends of the lead wire 30 are soldered to the pins 21 and 28, and both ends of the lead wire 31 are soldered to the pins 22 and 26. Both ends of the lead wire 32 are connected to the pins 24 and 25 by soldering.

FIG. 3 shows a part of another embodiment of the present invention.

In this embodiment, the correction resistor _Ra is wound around the drive coil 11 in the above-described embodiment (the winding is wound as a conductive wire folded so that the generated magnetic fields cancel each other). Correction resistor R
both ends of _a are connected by thermal welding on the main substrate 18. The correction resistor _Ra is made of the same material as the drive coil 11 or has the same resistance temperature coefficient as the drive coil 11. Although the drive coil 11 generates heat when energized, the correction resistor _Ra is always kept at the same temperature as the drive coil, the detection coil, etc., so that the temperature characteristics are superior to those in the above-described embodiment. In the above embodiment, the correction resistance R _a is inserted between the output circuit 12 and the driving coil 11, but the correction resistor R _a as shown in FIG. 4 in this embodiment is driving coil 11 and the driving current It is inserted between the detection resistor R _s and the detection resistor R _s .

As described above, according to the present invention, the drive current detection resistor is connected in series with the drive coil of the electromagnetic drive device, and the drive output is detected in parallel with the drive coil and the drive current detection resistor. A speed signal detection circuit in which a resistor and a drive output detection capacitor are connected in series, and the voltage across the drive current detection resistor and the voltage across the drive output detection capacitor are compared and calculated to detect the speed signal of the drive coil. In the electromagnetic drive device including the drive coil, the correction resistor is connected in series to the drive coil, and the correction resistor is mounted so as to be integrated with the drive coil or the drive coil bobbin. Assembling corresponding to one becomes unnecessary, and assembling workability and productivity can be improved.

[Brief description of drawings]

FIG. 1 is a schematic view showing a part of an embodiment of the present invention, FIG. 2 is a sectional view taken along the line II-II of FIG. 1, and FIGS. 3 (a) to (c).
Is a front view, a side view and a bottom view showing a part of another embodiment of the present invention, FIG. 4 is a circuit diagram showing an L / R integrating circuit of the same embodiment, and FIG. 5 is a conventional electromagnetic drive device. FIG. 6 is a circuit diagram showing a speed signal detection circuit, and FIG. 6 is a schematic diagram showing an example of an electromagnetic drive device. 11 ...... drive coil, _{R s} ...... drive current detection resistor, R ...
... Drive output detection resistor, C ... Drive output detection capacitor, _Rc ... Correction resistor, 14 ... Drive coil bobbin.

Continuation of the front page (72) Inventor Shinichi Niwa 14-888 Ako, Komagane City, Nagano Sanko Seiki Seisakusho Co., Ltd. Komagane Plant (56) Reference JP-A-59-156139 (JP, A) JP-A-1 -152984 (JP, A) Actually opened 51-127783 (JP, U)

Claims (1)

[Scope of utility model registration request] 1. A drive current detection resistor is connected in series with a drive coil of an electromagnetic drive device, and a drive output detection resistor and a drive output detection capacitor are connected in series so as to be parallel to the drive coil and the drive current detection resistor. The electromagnetic drive device having a speed signal detection circuit connected to detect the speed signal of the drive coil by comparing and calculating the voltage across the drive current detection resistor and the voltage across the drive output detection capacitor. An electromagnetic drive device in which a correction resistor is connected to the coil in series, and the correction resistor is mounted so as to be integrated with the drive coil or the drive coil bobbin.