JPS61214768A - Detector of movable unit in linear motor - Google Patents

Abstract

PURPOSE:To detect the position of a movable element in noncontacting state by detecting the lines of magnetic force of a plurality of magnets of the element, and selecting the signal of a magnetic force plate sensor by the signal logic state. CONSTITUTION:A movable element 1 of a linear motor is supported at the prescribed interval in parallel with tees, and magnets 2 are disposed longitudinally. A linear encoder magnetizing plate 6 is provided oppositely to the element 1, and linear encoder sensors SL1-SLn are disposed at the opposed position. Magnetic position detectors 5V1-5W1 are disposed at 2/3 pitch, and the drive coil 4 of the element 1 is controlled to be energized by an inverter 6. Thus, the outputs of the sensors LS are selected by a linear encoder converter 10 by the output of the detector 5 through a magnetic position distributor 9, and input to a calculator 11 which obtains the position and the traveling speed of the element 1.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a detection device for a movable element in a linear motor, and particularly relates to an improvement to a detection apparatus suitable for controlling the position of a movable element.

[Background of the invention]

In conventional linear motor control devices, consideration was not given to cases in which the mover moves over long distances or at high speeds6.
As stated in Publication No. 7, a rotary ballast generator is attached to the rotor to detect the position and speed of the movable element, and wiring is made to take in the paus signal to the control circuit. be. If a contact type detector such as a rotary pulse generator or signal wiring is used, there is a limit when the movable element can move over a long distance, and it may cause problems even when moving at high speed. Become.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a detection device for a movable element in a linear motor, which makes it possible to detect the position of the movable element during long-distance movement or high-speed travel without mechanical contact.

[Summary of the invention]

In order to achieve the above object, the present invention detects the lines of magnetic force of a plurality of magnets attached to the mover, and uses the signal logic state to generate a signal from a magnetic plate sensor that detects the lines of magnetic force of a magnetic plate interlocked with the mover. The position of the movable element is detected in the contacted state by selecting the movable element.

That is, in a linear motor equipped with a movable element that faces a plurality of drive coils arranged in a straight line and moves parallel to the arrangement direction, the linear motor has the same length as the movable element and is interlocked with the movable element. A magnetic plate is provided, and a magnetic plate sensor is provided which is arranged along the moving direction of the magnetic plate at a pitch equal to the length of the magnetic plate and outputs a pulse train signal with a predetermined repetition period as the magnetic plate moves. , a plurality of magnets are arranged along the longitudinal direction of the movable element so that magnetic poles with different polarities are alternately located on the movable element, and at least one magnet is arranged at each of the adjacent magnetic poles in accordance with the arrangement pitch of the magnetic plate sensor. Magnetic sensors are placed at each position and at one position between them, each of which outputs a logic signal in response to the polarity of the electric magnet.

A switching device is provided for selecting the output of the magnetic plate sensor corresponding to the magnetic sensor that outputs 0 only when the logical product of the logical signals of the respective magnetic sensors is O, and the output of the selected magnetic plate sensor is provided. 1. A detection device for a movable element in a linear motor, comprising a calculation device that calculates the position or moving speed of the movable element using pulses.

[Embodiments of the invention]

Next, one embodiment of the present invention will be described with reference to FIGS. 1 to 3.

FIG. 1 shows the main parts of a linear motor and the overall configuration of one detector according to the present invention.

Three phases (U, V, W) are set as n (n≧1 positive number>
(7) Tee X (3U1,3V,,3W,,-.

3.U,,3V,,3W,), drive coil 4 with stator (4U1.4V,,4W,,4U,,4V,).

4), magnetic pole position detector 5 (5U, , etc.) such as a Hall element
5V1,5W,, ,5U,,5V,.

5W, ), linear encoder sensors LS such as magnetoresistive elements, LS2', . . . , LS.

The movable element 1 is supported by a support mechanism (not shown) so that a constant gap is maintained parallel to the teeth 2, and can freely move in the direction in which the drive coils 4 are arranged. Further, a plurality of magnets 2 are arranged in the movable element 1 in such a manner that magnetic poles having different magnetic properties are alternately located in the longitudinal direction of the movable element 1. That is, they are arranged in the order of S pole, N pole, S pole, and N pole.

A linear encoder magnetized plate (magnetic plate) 6 is provided in a direction opposite to the movable element 1 so as to be freely movable in the arrangement direction of the drive coils 4 in conjunction with the movable element 1. The reason why the linear encoder magnetized plate 6 is provided in the opposite direction to the movable element 1 is to prevent the influence of leakage magnetic flux of the magnet 2. A position facing this linear encoder magnetized plate 6,
Linear encoder sensors (magnetic plate sensors) LS, ~LS are arranged at a pitch corresponding to the length of the movable element 1.

E-)- on the side facing the mover 1 at a predetermined interval.
Magnetic position detectors 5 consisting of combinations +7) (5V, 5U1, 5W1) are arranged for each pitch of the linear encoder sensor. That is, the magnet 2 provided on the mover 1
is magnetized perpendicularly to the upper surface direction of the magnet 3 and the movable element 1, with north and south poles arranged alternately at a pitch of π. Correspondingly, magnetic position detector 5V1, 5U1, 5W
, are arranged at a pitch of 2/3π, as shown in FIG. Further, the teeth 3U1 to 3W are arranged at a pitch of 4/3π, each having a width of π.

Next, FIG. 2 shows the control circuit of the linear motor.

In Figure 2, coil 4U for driving movable +1
, ,4V, ,4W, ,-,4U, ,4V
, .

4W is connected to the inverter 7, and the drive power source of the inverter 7 is connected to the DC power source 13.

Further, a comparison amplifier 8 is connected to the inverter, and the difference between the detection signal from the current detector 14 and the current command signal from the calculation section 11 is determined, and the duty of the current flowing through the inverter 7 is controlled. There is.

The calculation unit 11 calculates the magnetic pole 2 detected by the magnetic pole position detectors 5V, 5U1 and 5W1 via the magnetic pole position distributor 9.
In response to the detection signal of the movable element 1, a signal for each layer to be energized to the drive coil 4 is output as a current command.

The magnetic pole position detector 5 outputs a logic signal H when there is no magnetic flux due to the magnet 2 and when the magnetic pole is an S pole, and outputs a signal with a cross logic when it is an N pole.

The linear encoder sensor Sl outputs a repetitive pulse signal with a predetermined period when the linear encoder magnetized plate 6 moves together with the movable element 1. For example, in the case shown in FIG. 2, the output of the linear encoder sensor LS□ is logic H.

However, if the mover 1 moves in the direction of the arrow, that is, to the right in the drawing, the linear encoder magnetized plate 6 overlaps both the linear encoder sensors LS and LS, and the linear encoder sensors LS1 and L
S, receives pulse output from magnetic pole position detector 5V,
Since the N pole of the magnet 2 faces the N pole of the magnet 2, the output of the magnetic pole position detector 5V is logical, and the output of the linear encoder sensor LS is selected by the linear encoder switch 10 based on the output of the magnetic position distributor 9. The selected signal is input to the calculation unit 11! Note that the command device 12 commands the current to be applied to the coil 4, and the speed of the movable element 1 is proportional to the commanded current.

Next, the detection operation will be explained in detail based on FIG. Third
The figure shows the relative positional relationship between the magnet 2 provided on the movable element 1, the magnetic position detector 5, the linear encoder magnetized plate 6, and the linear encoder sensor LS. Further, FIG. 4 is a signal waveform diagram showing detection signals from each sensor in a magnetic series.

Now, when the movable element 1 is located at the position shown in FIG.
When the output logic of U1 changes from H to L, it is 5V, then L
, 5W1 are in the H state. On the other hand, the magnetic force position detectors 5U, 5V, 5W, which are not affected by the magnetization of the magnet 2, are in a logic H state. As the movable element 1 moves to the right in the drawing, the magnetic pole position detection signal changes as shown in the drawing.

Furthermore, as the movable element 1 moves, the linear encoder magnetized plate 6 also moves, and this movement causes the linear encoder sensor LS1. LS2 also outputs a pulse signal as shown in FIG. The selection of the output signal of this linear encoder sensor is performed by a switch 10 (see Fig. 2), which selects the AND of the detection signals of the magnetic pole position detectors 5U1, 5V, 5W, and the magnetic position detector. 5U2, 5V.

It operates to select either the linear encoder sensor LS or LS depending on the logic state of the detection signal of 5W. That is, as can be seen from the 4th rjR,
Magnetic position detector 5U1,5V engineering.

If the AND of the detection signal logic of the 5W sensor is L, the output signal of the linear encoder sensor LS is selected. At this time, the magnetic position sensor 5U, 5V, etc.

5W, the detection signal logic is all H) Primary mover 1
The magnetic position detector 5U,,5V, moves.

When reaching the position 5W, the logical product of each signal becomes L, so the output signal of the linear encoder sensor LS is selected.

By the way, the span SP indicated by the dashed line in Fig. 4
In this section, the output signals of the linear encoder sensors LS1 and LS overlap, but in this span SP section, priority should be set to the linear encoder sensor located at the front in the moving direction of the mover 1 so that they are not selected at the same time. In this case, LS, ) is selected preferentially.

As described above, when the AND of the detection signal logic of the magnetic position detector 5 is L''Q, the corresponding output signal of the linear encoder sensor is selected by the switch 10. This allows you to calculate the running speed.The same goes for the rest.

A signal similar to the waveform shown in Fig. 4 is detected by the magnetic position detector 5U.
,,5V,,5W, and linear encoder sensor L
This will be repeated until S.

In the above explanation, we will explain the case of a three-layer linear motor.
However, it goes without saying that it is generally applicable to m-phase Niata.

Further, in the above embodiment, each sensor is emitted using magnetism, but instead of the magnet 2, a light emitting element is arranged, and the light emitted from the light emitting element is turned on one by one, and the light from the light emitting element is detected by the light receiving element. It is possible to implement the present invention optically, and in this case, it is effective when considering the influence of magnetic noise.

[Effects of the Invention] As described above, according to the present invention, a mover of a linear motor can be obtained! Can be detected in contact state.

Therefore, even when the movable element moves over a long distance or travels at high speed, it is extremely effective since there is no direct contact or signal wiring as in the prior art.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram of the embodiment by Kenmei Sakai, FIG. 2 is a block diagram showing the control circuit, and FIG. 3 is an explanatory diagram showing the relative positional relationship between the movable element, the encoder magnetized plate, and each sensor.
FIG. 4 is a time chart showing the output signal waveforms of each sensor. 1...Mover, 2...Magnet, 3...Teeth, 4
... Drive coil, 5... Magnetic pole position detector, 6...
Linear encoder, 7... Inverter, 8... Comparison amplifier, 9... Magnetic pole position distributor, 10... Linear encoder switching device, 11... Arithmetic unit, 12... Command unit, 13.・・DC power supply, 14 ・・Current detector, LS・
...Linear encoder sensor.

Claims (1)

[Scope of Claims] 1. A linear motor including a movable element that faces a plurality of linearly arranged drive coils and moves parallel to the arrangement direction thereof, the linear motor having the same length as the movable element. A magnetic plate is provided which interlocks with the movable element, and is arranged along the moving direction of the magnetic plate at a pitch equal to the length of the magnetic plate, and outputs a pulse train signal with a predetermined repetition period as the magnetic plate moves. A magnetic plate sensor is provided, and a plurality of magnets are arranged along the longitudinal direction of the movable element so that magnetic poles with different polarities are alternately located on the movable element, and the magnetic plate sensor is arranged at least at each arrangement pitch of the magnetic plate sensor. Magnetic sensors that output a logic signal in response to the polarity of the electric magnet are arranged, one at each of adjacent magnetic poles and one at a position between them, and the logical product of the logic signals of the respective magnetic sensors is arranged. is provided with a switching device that selects the output of the magnetic plate sensor corresponding to the magnetic sensor that outputs 0 only when A detection device for a movable element in a linear motor, characterized in that it is provided with a calculation device for calculation.