JPH05184127A - Linear pulse motor - Google Patents

Abstract

PURPOSE:To accurately obtain an electronic control signal and to accurately perform a control based on the signal. CONSTITUTION:Two sets of primary coils 1, 2 of a phase modulation type inductosyn are disposed to be alternately deviated by 1/4 pitch of a phase on the same gap surfaces as teeth for constituting a magnetic circuit of a stator side. A driving circuit for supplying AC currents having phases deviated by 90 deg. to the coils 1, 2 is provided. A secondary coil 3 of the inductosyn is formed on the same surface as teeth of a movable element opposed at a constant gap to the stator. Further, a phase difference between phase change information obtained from the coil 3 and reference signals of the coils 1, 2 are detected, and a phase correcting position error signal is obtained by using the difference.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linear pulse motor, and more particularly to a linear pulse motor having a position error detecting function by an inductosyn.

[0002]

2. Description of the Related Art Conventionally, in a linear pulse motor, a magnetic circuit is constructed with a movable element and a stator sandwiching a parallel gap, and a magnetic bias by a permanent magnet and a magnetic field sequentially switched by a driving coil are applied to this magnetic circuit. The mover was moved by. When this linear pulse motor is used as an actuator for magnetic recording, the stopping accuracy is
It is determined by the mechanical precision of the teeth forming the magnetic circuit, the parallelism of the gap, and the like. Linear pulse motor
As an actuator for a 3.5-inch floppy disk 135TPI, it has many market achievements by taking advantage of its features of ultra-small size, light weight and high accuracy. Larger capacity
406TP for 3.5 inch floppy disk
In order to triple the I and track accuracy, the linear pulse motor tooth pitch is tripled to improve the accuracy of the actuator.

[0003]

In a magnetic recording apparatus using a linear pulse motor, when further increasing the track density, relying on the mechanical accuracy of the tooth pitch causes a technical limit. For this reason, it is generally considered to be used in combination with an external scale, but there are many difficulties such as an increase in size of the device in order to optimize the external scale in terms of accuracy, reliability, cost, and the like.

[0004]

It is an object of the present invention to improve the disadvantages of the conventional example, and in particular, to provide a linear motor which can obtain an electronic control signal with high accuracy and can perform position control with high accuracy based on the electronic control signal. That is the purpose.

[0005]

According to the present invention, a magnetic circuit is constructed with a mover and a stator sandwiching a gap parallel to each other, and a magnetic bias and a drive for driving the permanent magnet to the magnetic circuit. In a hybrid type linear pulse motor that moves the mover in steps by switching each phase of the coil, a phase modulation type inductin sync on the same gap surface as the teeth forming the magnetic circuit on the stator side. Two sets of primary side coils are arranged with a phase shift of 1/4 pitch from each other, and each coil is equipped with a drive circuit for passing an alternating current with a 90 ° phase shift, keeping a certain gap with the stator. A secondary coil of the inductin is formed on the same surface as the facing tooth portion of the mover, and the phase difference between the phase change information obtained from the secondary coil and the reference signal of the primary coil is detected. , Using this, a position error signal for position correction is obtained. Is adopted. This aims to achieve the above-mentioned object.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. First, based on FIG. 1, the operation principle of the phase modulation type inductocin will be described. Reference numeral 1 in FIG.
Reference numeral 2 indicates two sets of coils in which their coil pitches are out of phase with each other by 1/4 pitch. A signal having a waveform as shown in FIG. 2, that is, an alternating current having the same amplitude and the same period with a phase difference of 90 ° from each other is applied to each of the coils 1 and 2. In FIG. 1, the A-phase coil 1
, Sin ωt waveform 4, B phase coil 2 cos ωt waveform 4
Shed. As a result, in the secondary coil, the output is constant and the induced voltage "sin
(Ωt + (2π / p) x) ”is obtained.

In this method, since the output is constant, the primary and secondary
The next gap adjustment can be rough. The signal thus induced in the secondary coil is amplified by the amplifier circuit 15 shown in FIG. 5, and the phase difference with the primary A-phase signal is detected by the comparator 16 by the phase difference detector 17. Is detected as the analog error amount 21 through the integrator 18, and the method is detected as the digital error amount 22 by counting the phase difference using the interpolation pulse. 6 to 9 show an example in which the above-mentioned phase modulation type inductosyn is configured in the gap portion of the linear pulse motor. Of these, FIG. 6 shows the appearance of the linear pulse motor. Since the teeth 34 and 35 constituting the magnetic circuit in the mover 31 and the stator 32 maintain a constant gap 32, the retainer of FIG. The held ball bearing 61 and the roller 62 are used. In this embodiment, in the primary coil, the stator is arranged on the gap surface of FIG.
These coils, which are coils for layers A and B, respectively, are arranged so as to be parallel to the teeth 52 of the magnetic circuit of the stator, and the gap between the coils 43 and the teeth 42 of the magnetic circuit is 42. It is set wider than the gap of 52 and 52.

Next, the secondary coil 43 is arranged parallel to the teeth 42 on the surface of the movable element gap side in FIG. On the other hand, in the linear pulse motor, the gap between the tooth 42 of the mover and the tooth 52 of the stator needs to be controlled with high accuracy of several tens [μm] in order to obtain thrust. Therefore, the ball of the retainer shown in FIG. The bearing 61 and the roller 63 are used.

In this embodiment, since the phase modulation type with a small gap accuracy is adopted as the inductin, the parallelism between the primary coil and the secondary coil and the teeth of the stator and the mover is rough. can do. Therefore, if the gap management is performed only on the linear pulse motor side, the gap on the inductosyn side can be automatically filled.

[0010]

As described above, according to the present invention,
By inserting the primary and secondary coils of the phase-modulation type inductin of the linear pulse motor into the gap, the gap of the inductin can be adjusted simply by performing the gap management required in the magnetic circuit of the linear pulse motor. Can be secured, and by using the position information obtained by the inductin thus obtained, it is possible to obtain a control signal capable of highly accurate position control. Can be improved. A linear pulse motor can be provided.

[Brief description of drawings]

FIG. 1 is a principle view showing a phase modulation type inductin used in an embodiment of the present invention.

2 is an explanatory diagram showing waveforms applied to the two primary coils of FIG. 1 and output waveforms of the secondary coil. FIG.

FIG. 3 is an explanatory diagram showing a phase change of an output of the secondary coil in FIG.

4 is a block diagram showing a circuit that forms a waveform applied to the two primary coils of FIG. 1. FIG.

5 is an explanatory diagram showing a processing circuit for a waveform output from the secondary coil of FIG. 1. FIG.

6 to 9 are explanatory views showing the structure of a linear motor equipped with the coil of the control circuit of FIG. 1.

[Explanation of symbols]

1 primary side A phase coil 2 primary side B phase coil 3 secondary coil 4 signal waveform applied to primary side A phase coil 5 signal waveform applied to primary side B phase coil 6 secondary coil output 21 secondary side output Phase error signal processed as an analog quantity by processing the output signal 22 Phase error signal processed as a digital quantity by processing the output signal on the secondary side

Claims (2)

[Claims] 1. A magnetic circuit is constructed by interposing a gap in which a mover and a stator are parallel to each other, and a magnetic bias by a permanent magnet and each phase of a drive coil are switched to this magnetic circuit. , In a hybrid type linear pulse motor that moves the mover in a stepwise manner, the primary side coils of the phase-modulating type inductin are mutually 1/1 on the same gap surface as the teeth forming the magnetic circuit on the stator side. Two sets are arranged with a phase shift of 4 pitches, each coil is equipped with a drive circuit for flowing an alternating current with a 90 ° phase shift, and the teeth of the mover facing the stator with a constant gap maintained. The secondary coil of the inductous membrane is formed on the same surface as the part of, and the phase difference between the phase change information obtained from the secondary coil and the reference signal of the primary coil is detected, and position correction is performed using this. For Linear pulse motor, characterized in that to obtain a 置誤 difference signal. 2. The linear pulse motor according to claim 1, wherein the frequency of the drive circuit used for the primary side coil of the inductosyn is separated from the frequency region used for recording and reproduction.