JP2000197337A - Linear motor and positioning device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To deal with the change of the number of coils flexibly so as to be able to change the movable range of a linear motor easily, and to reduce the number of distributing wires, by providing modules having coils and connectors, connecting a plurality of modules to one another with connectors and constituting a stator for a linear motor. SOLUTION: A linear motor (stator) is composed of combinations of coil modules 1-n each of which is a pair of a coil 104 and a switch 120. Each coil module 1-n owns each distributing wire for driving currents DRV, coil section SEL, and grouding 190 in common, and a coil module is connected with an adjoining coil module or driver through a connector 130. Each switch 120 of the coil modules 1-n has an inherent identification number respectively, and a driving current DRV is caused to flow in a coil 104, when a coil selection SEL signal coincides with its own identification number.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linear motor having a plurality of coils which need to selectively switch a coil to be energized according to a detection position of a movable body. The invention also relates to a positioning device for positioning an object using such a linear motor.

[0002]

2. Description of the Related Art FIG. 5 shows a configuration of a conventional linear motor.

The linear motor shown in FIG.
04 are arranged side by side on a straight line. The coil support member 303 supports the coil 304. A pair of guides 3
02 on both sides of the coil support member 303
Are provided in parallel with the arrangement direction of each coil. A table top plate 301 is provided on the guide 302 with the bearing 30.
6 is attached. Table top plate 301
Are movably guided by the guide 302 in the coil arrangement direction. Further, the table top plate 301 has a permanent magnet 3
The permanent magnets 305 are arranged in four pairs with alternating polarities along the coil arrangement direction.

A position detector (linear scale) 307 for detecting the position of the table top 301 is provided beside the guide 302. An up / down signal is output from the position detector 307 according to the moving amount and direction of the table top 301. The output signal is taken into the counter unit 310, and the position information of the table top 301 is obtained. The counter unit 310 is initialized when the light blocking plate 308 attached to the table top plate 301 passes through the origin photo switch 309.

[0005] A servo controller 311 is connected to the counter unit 310, and a target position of the table 1 and a table top 301 obtained from the counter unit 310.
The PID operation is performed on the difference between the current position and the current position, and the control output obtained by this operation is output to the D / A converter 313 as a command value.

Next, FIG. 6 shows an example of a linear motor stator used in a conventional linear motor.

The linear motor stator shown in FIG. 1 has four coils arranged in a straight line, an amplifier 418 corresponding to each coil 404, and a detection resistor 416 provided in each amplifier 418.
And a differential amplifier 417. Coil 40
4 is measured by the differential amplifier 417 from the voltage across the detection resistor 416, and the difference from the command is amplified by the power operational amplifier 418 to form a current feedback circuit. In this example, a current feedback circuit is provided for each coil.

FIG. 7 shows another example of a linear motor stator used in a conventional linear motor.

In FIG. 1, instead of switching control commands, a switch 1 composed of an FET or the like connected to each coil is used.
19 are sequentially switched.

[0010]

However, in the above-described conventional example, when a long-stroke linear motor in which, for example, several tens of coils are connected is formed, the wiring from the driver to the linear motor becomes extremely large. Would. Since the wiring here must pass the drive current, it cannot be made very thin, and the connector also becomes large,
When the number of wirings for the drive current increases, it becomes difficult to mount the linear motor.

Further, in the above-mentioned conventional example, when an attempt is made to add a coil for the purpose of increasing the movable range of the driver or the like, a drastic change of the linear motor driver such as addition of an amplifier or addition of a changeover switch is required. You. For this reason, in the conventional linear motor, a change in the number of coils cannot be easily performed in order to increase the stroke by increasing the number of coils because the entire system needs to be changed. Therefore, the linear motor has been designed and manufactured in a state where the movable range is determined in advance.

It is a first object of the present invention to change the number of coils of a linear motor so that the movable range of the linear motor can be changed freely and easily. A second object of the present invention is to improve a conventional linear motor and reduce wiring from a driver to the linear motor.

[0013]

According to the present invention, there is provided a linear motor comprising a module having a coil and a connector, wherein a plurality of the modules are connected to each other by the connector. Is constituted.

Preferably, the connector is a connector for electrically connecting the modules. Further, it is preferable that a coil selection signal is transmitted to the module via the connector in order to select a coil to be energized among the plurality of coils of the plurality of modules.

It is preferable that the module has a switch for controlling power supply to the coil, and it is preferable that the switch be controlled based on the coil selection signal.

It is preferable that electric power to be supplied to the coil be supplied through the connector. Further, a current flowing through the coil may be fed back via the connector.

Preferably, the connector is a connector for mechanically connecting the modules.

Further, in order to achieve the above object, a linear motor according to another aspect of the present invention includes a plurality of coils, a switch provided for each of the coils, and a switch for controlling energization to each of the coils. A magnet facing the plurality of coils and moving relative to the coils, wherein the plurality of coils and the plurality of switches are provided integrally with the linear motor stator; .

Further, it is desirable to have a driver for controlling a coil selection signal for selecting the coil to be energized and a driving power for energizing the coil.

It is preferable that a selector for controlling the switch based on the coil selection signal is provided on the linear motor stator.

[0021]

<First Embodiment> FIG. 1 shows a linear motor stator and a driver used for a linear motor according to a first embodiment of the present invention.

Referring to FIG. 1, an amplifier 118 is provided in the driver to amplify a drive command signal from a controller. The driver includes a detection resistor 116 and a differential amplifier 117. Coil 104
Is measured by the differential amplifier 117 from the voltage across the detection resistor 416, and the difference from the command is amplified by the amplifier 118 to form a current feedback circuit.

The linear motor stator according to the present embodiment is constituted by a combination of a coil module in which a coil 104 and a switch 120 are paired. Each coil module shares a drive current line, a coil selection signal line, and a ground line, and is configured to be connectable to an adjacent coil module or driver through the connector 130. That is, the stroke can be changed only by adding the coil module electrically through the connector. Furthermore, if a coil module is provided with a connector for mechanically coupling with an adjacent coil module or driver, in addition to the electrical connector, the module can be easily added.

To configure the coil modules, the switches 120 of each coil module are assigned unique numbers that are not duplicated, and each switch 120 controls ON / OFF according to a coil selection signal. Is configured. That is, the controller
The switch number corresponding to the coil to be selected is sent to the linear motor stator as a coil selection signal, and the switch 120 of each coil module is connected when the coil selection signal matches its own unique number, and the drive current is The wire and the coil 104 are energized.

In the linear motor of the present invention, the number of wires from the driver to the linear motor can be greatly reduced by configuring the stator as described above. For example,
In the case of a linear motor having ten coils 104, in the conventional configuration, ten drive current lines and one ground line 1 are used.
A minimum of one (or ten ground lines) was required in total. On the other hand, according to the configuration of the present invention, it is possible to reduce the number of drive current lines and ground lines to one and four coil signal lines, for a total of six. As the number of coils 104 increases,
The number of wirings that can be reduced by the effects of the present embodiment increases. That is, in the conventional configuration, N + 1 wires from the driver to the stator are required for the number of coils N, but in the configuration of the present embodiment, the wiring from the driver to the stator is 2 + lo.
g2N (decimal part is rounded up) book.

FIG. 2 shows the relationship between the number of coils and the number of wires from the driver to the stator.

As can be seen from the figure, the present embodiment is more effective as the number of coils increases as the number of wirings can be significantly reduced as compared with the conventional case.

In the present embodiment, the number of signal lines obtained by converting the number of coils into bits is used. However, if a serial communication technique such as RS-232C is used, one signal line can be used regardless of the number of coils.
It is also possible to configure with a single signal line.

In addition, in this embodiment, the wiring from the driver to the linear motor stator can be made almost thinner for the same reason as in the above-described embodiment, which is very effective in terms of mounting.

Further, in this embodiment, if a larger number of coil selection signal lines are provided in preparation for a change in the number of coils, the number of coils can be increased by changing the stroke without preparing an extra amplifier or switch in advance. can do. Therefore, the cost and space of the linear motor can be reduced. In addition, since the number of coil signal lines can be increased to almost twice the number of coils simply by adding one, it is easy to prepare for a change in the number of coils. When the serial communication technology is used for the coil selection signal, the number of coils is one, regardless of the number of coils. Therefore, even if the number of coils is changed, the driver does not need to change.

Further, by configuring the linear motor by a combination of coil modules, it is possible to more flexibly cope with a change in the number of coils. In other words, when adding a coil for reasons such as an increase in the stroke of the linear motor, the conventional configuration required modification of the linear motor and driver, whereas the configuration of the present embodiment added a coil module to the linear motor. Just do it. Thus, it is not necessary to redesign each time according to the stroke of the linear motor, and the driver and the coil module can be shared, so that a significant cost reduction can be achieved. Also, a general-purpose linear motor can be manufactured.

As described above, according to the configuration of the present embodiment, in a linear motor composed of a plurality of coils, such as a long-stroke linear motor, the number of wires between the driver and the linear motor stator is greatly increased. Since the wiring itself can be made very thin, a connector for connecting an adjacent coil module or a driver can be made small, which is advantageous when mounting. In addition, since the driver and the linear motor do not need to be changed even when the number of coils is changed due to the change in the stroke of the linear motor, it is possible to flexibly cope with the change in the stroke.

<Second Embodiment> FIG. 3 shows a linear motor stator and a driver used in a linear motor according to a second embodiment of the present invention.

In the figure, the same components as those in the above-described embodiment are denoted by the same reference numerals, and description thereof is omitted.

A drive current line for supplying a drive current to the coil, a coil selection signal line for selecting a coil to be energized, and a ground line are provided between the driver and the linear motor stator.

In the linear motor stator, N coils 104 each having a number suitable for the stroke of the linear motor mover (not shown) are linearly arranged along the driving direction of the linear motor mover (not shown). Are arranged side by side. A switch 121 corresponding to each coil 104 is installed in the linear motor stator.

A coil selection signal from the controller 111 is input to a selector 122 using a multiplexer, a PLD element, and the like in the stator of the linear motor.
1 is controlled to connect / disconnect the coil 104 and the drive current line. Here, the number of coil selection signal lines required to control ON / OFF of the N switches 121 is log2N (decimal parts are rounded up).
Can be configured.

The linear motor of the present invention can greatly reduce the number of wires from the driver to the linear motor, as in the above-described embodiment. Also, as the number of coils increases, the number of wirings can be significantly reduced as compared with the conventional case, which is more effective.

In this embodiment, as many signal lines as the number of coils converted into bits are used. However, if a serial communication technology such as RS-232C is used, one signal line can be used regardless of the number of coils.
It is also possible to configure with a single signal line.

Further, according to the conventional configuration, not only the number of wirings is large, but also most of the wiring from the driver to the stator is a drive current line. In general, it was necessary to make the wiring thicker. On the other hand, in the configuration of the present embodiment, most are coil selection signal lines, and the wiring from the driver to the stator can be made thin.

Further, according to the present embodiment, it is possible to mount a linear motor having a different number of coils without changing the driver by keeping a sufficient number of coils that can be handled by the coil selection signal line. For this reason, a common driver can be used, and only the linear motor can be changed according to the specifications of the device, so that the cost can be reduced.

<Embodiment 3> FIG. 4 shows a positioning device using any of the linear motors described above.

The linear motor shown in FIG.
04 are arranged side by side on a straight line. The coil support member 203 supports the coil 204. A pair of guides 2
02 on both sides of the coil support member 203,
Are provided in parallel with the arrangement direction of each coil. The guide 202 has a table top 201 on which the bearing 20 is attached.
6 is attached. Table top 201
Are guided by the guide 202 so as to be movable in the coil arrangement direction. Further, the table top 201 has a permanent magnet 3
The permanent magnets 205 are arranged in four pairs with the polarities alternately arranged along the coil arrangement direction.

A position detector (linear scale) 207 for detecting the position of the table top 201 is provided beside the guide 202. An up / down signal is output from the position detector 207 according to the amount and direction of movement of the table top 201. The output signal is taken into the counter unit 210, and the position information of the table top 201 is obtained. The counter unit 210 is initialized when the light blocking plate 208 attached to the table top 201 has passed through the origin photo switch 209.

A controller 211 is connected to the counter unit 210, and performs PID calculation of a difference between a target position of the table 1 and a current position of the table top 201 obtained from the counter unit 210, and outputs a drive command and a coil selection signal. I do.

According to the present embodiment, in the positioning device for mounting and positioning an object, the number of wires between the driver and the linear motor stator can be greatly reduced, and the wires themselves can be made very thin. . Further, a connector for connecting an adjacent coil module or a driver can be reduced in size, which is advantageous when mounting. In addition, since the driver and the linear motor do not need to be changed even when the number of coils is changed due to the change in the stroke of the linear motor, it is possible to flexibly cope with the change in the stroke of the positioning device.

[0047]

According to the linear motor according to the first aspect of the present invention, the linear motor can be constituted by a combination of modules, and the number of coils can be flexibly changed, so that the cost can be reduced. .

According to the tenth aspect of the present invention, the number of wirings can be reduced and the wirings can be made thinner.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a linear motor stator and a driver used in a linear motor according to a first embodiment of the present invention.

FIG. 2 shows the relationship between the number of coils and the number of wires in the embodiment of FIG. 1 and a conventional example.

FIG. 3 is a schematic diagram showing a linear motor stator and a driver used in a linear motor according to a second embodiment of the present invention.

FIG. 4 is a schematic view of a positioning device according to a third embodiment of the present invention.

FIG. 5 is a schematic view of a conventional positioning device.

FIG. 6 is a schematic view of a conventional linear motor stator.

FIG. 7 is a schematic view of another conventional linear motor stator.

[Explanation of symbols]

 104 coil 111 controller 116 detection resistor 117 differential amplifier 118 amplifier 120 switch 121 switch 122 selector 130 connector 201 table top plate 202 guide 203 coil support member 204 linear motor coil 205 movable magnet 206 bearing 207 position detector 208 light shielding plate 209 origin photo Switch 210 Counter unit 211 Controller

Claims (13)

[Claims] 1. A linear motor, comprising: a module having a coil and a connector, wherein a plurality of the modules are connected to each other by the connector to form a linear motor stator. 2. The linear motor according to claim 1, wherein the connector is a connector for electrically connecting the modules. 3. The module according to claim 2, wherein a coil selection signal is transmitted to the module via the connector in order to select a coil to be energized among the plurality of coils of the plurality of modules. Linear motor. 4. The module according to claim 3, wherein the module has a switch for controlling energization of the coil.
The linear motor as described. 5. The linear motor according to claim 4, wherein the switch is controlled based on the coil selection signal. 6. The linear motor according to claim 3, wherein the coil selection signal is transmitted by serial communication. 7. The linear motor according to claim 2, wherein electric power supplied to the coil is supplied via the connector. 8. The method according to claim 2, wherein a current flowing through the coil is fed back via the connector.
7. The linear motor according to any one of 7. 9. The linear motor according to claim 1, wherein the connector is a connector for mechanically connecting the modules. 10. A plurality of coils, a switch provided to correspond to each coil, for controlling energization of each coil, and a magnet facing the plurality of coils and moving relatively to the coil. The linear motor, wherein the plurality of coils and the plurality of switches are provided integrally with a linear motor stator. 11. A driver for controlling a coil selection signal for selecting a coil to be energized and a driving power for energizing the coil.
The linear motor as described. 12. The linear motor according to claim 10, wherein a selector that controls the switch based on the coil selection signal is provided on the linear motor stator. 13. A positioning device comprising the linear motor according to claim 1.