JP2815655B2 - Moving magnet type linear motor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a movable magnet type linear motor.

2. Description of the Related Art At present, various types of movable magnet type linear motors exist. The apparatus disclosed in Japanese Patent Laid-Open Publication No. Sho 59-70178 will be described with reference to FIGS. 8 to 10 as a conventional example of a movable magnet type linear motor.
The movable magnet type linear DC motor 1 includes a mover 2 and a stator 3. First, the mover 2 includes a yoke 4 having a U-shaped cross section, a magnet 5 mounted on the bottom surface of the yoke 4, and a wheel 7 rotatably mounted at four corners of the yoke 4 via shafts 6. Consisting of The magnet 5 is formed by alternately magnetizing N poles and S poles in the longitudinal direction of the stator 3.

On the other hand, the stator 3 includes a long base plate 9 having a groove or a stepped guide portion 8 for guiding the rolling of the wheel 7, and a stator yoke fixed on a center line of the base plate 9. An armature 12 comprising an armature coil 11 continuously mounted on the stator yoke 10;
And Hall elements 13, which are magnetic field conversion elements, respectively attached to the side portions.

The armature coil 11 formed on the stator 3 is opposed to the magnet 5 of the mover 2 with a fixed gap therebetween, and together with the Hall element 13,
It is connected to a drive control circuit (not shown) including a drive circuit and a control circuit of a CPU (Central Processing Unit).

In such a configuration, in the movable magnet type linear DC motor 1, the mover 2 linearly moves on the stator 3 by the magnetic action between the magnet 5 and the current applied from the drive control circuit to the predetermined armature coil 11. Moving.

The movable magnet type linear DC motor 1 described above
In order to control the excitation switching timing, the Hall element 13 connected to the drive control circuit of the CPU detects the magnetic field generated by the magnets 5 facing each other, so that the position of the mover 2 can be detected without using a brush. It is supposed to be.

Problems to be Solved by the Invention A movable magnet type linear DC motor 1 as described above
The armature coil 11 is freely and linearly moved by program control of energization to each armature coil 11 by a drive control circuit of the CPU. However, the CPU of the above-mentioned device may run away due to external noise etc.
A malfunction will occur in energization of each armature coil 11 under program control. Then, the mover 2 becomes uncontrollable, and the device is damaged by, for example, overrunning on the stator 3 and coming off from above the base plate 9.

Means for Solving the Problems According to the invention as set forth in claim 1, a stator in which a number of coils are continuously arranged in a longitudinal direction is provided, and a movable member movably disposed on the stator has a stator. A movable circuit having a drive circuit for inputting a drive current to a coil of a stator, and a control circuit for controlling an output of the drive circuit, the magnet being provided with an N-pole and an S-pole alternately in the longitudinal direction; In a magnet type linear motor, a magnetic field conversion element facing the magnet of the mover is attached near both ends of the stator, and the output of the drive circuit connected in parallel with the control circuit is regulated in accordance with the detection of the magnet of the magnetic field conversion element. An overrun prevention circuit is provided.

According to a second aspect of the present invention, there is provided a stator in which a number of coils and a magnetic field conversion element for detecting the position of the mover are continuously arranged in the longitudinal direction, and the mover is movably disposed on the stator. A magnet is provided alternately with N poles and S poles in the longitudinal direction of the stator, a magnet facing the coil and the magnetic field conversion element is provided, and a driving circuit for inputting a driving current to the coil of the stator is provided. In a movable magnet type linear motor provided with a control circuit for controlling based on a detection value of a magnetic field conversion element, a magnetic field conversion element having higher sensitivity than other magnetic field conversion elements is provided near both ends of a stator, and these high sensitivity are provided. An overrun prevention circuit is provided for regulating the output of a drive circuit connected in parallel with the control circuit in response to detection of the magnet of the magnetic field conversion element.

According to the first aspect of the present invention, there is provided a stator in which a large number of coils are continuously arranged in the longitudinal direction, and a movable member movably disposed on the stator has N poles S in the longitudinal direction of the stator. A movable magnet type linear motor having a pole and a magnet opposite to the coil, a drive circuit for inputting a drive current to the coil of the stator, and a control circuit for controlling the output of the drive circuit. A magnetic field conversion element facing the magnet of the child was mounted near both ends of the stator, and an overrun prevention circuit was provided to regulate the output of the drive circuit connected in parallel with the control circuit in accordance with the detection of the magnet of the magnetic field conversion element. As a result, even if the mover becomes uncontrollable due to runaway of the drive control circuit, etc., when the mover moves to the vicinity of the end of the stator, the magnetic field conversion element turns on the magnet of the mover. Upon detection, the overrun prevention circuit operates,
The output of the drive circuit is regulated and the movement of the mover is stopped,
In addition, since the overrun prevention circuit and the drive control circuit are connected to the drive circuit in parallel, the drive of the mover is normally controlled by the drive control circuit in normal times, and regardless of the output of the drive control circuit only when the equipment is abnormal. The mover is stopped.

According to a second aspect of the present invention, there is provided a stator in which a number of coils and a magnetic field conversion element for detecting the position of the mover are continuously arranged in the longitudinal direction, and the mover is movably disposed on the stator. A magnet is provided alternately with N poles and S poles in the longitudinal direction of the stator, a magnet facing the coil and the magnetic field conversion element is provided, and a driving circuit for inputting a driving current to the coil of the stator is provided. In a movable magnet type linear motor provided with a control circuit for controlling based on a detection value of a magnetic field conversion element, a magnetic field conversion element having higher sensitivity than other magnetic field conversion elements is provided near both ends of a stator, and these high sensitivity are provided. By providing an overrun prevention circuit that regulates the output of a drive circuit connected in parallel with the control circuit in response to the detection of the magnet of the magnetic field conversion element, the existing movable magnet linear motor can be overrun. It is possible to obtain the movable magnet type linear motor overrun of the movable member is prevented only by providing a stop circuit.

Embodiment An embodiment of the invention will be described with reference to FIGS. 1 to 3. FIG. The same parts as those of the movable magnet type linear DC motor 1 illustrated in FIGS. 8 to 10 are denoted by the same names and reference numerals, and description thereof is omitted. First, in the movable magnet type linear motor 14 of the present embodiment,
A sensor probe 16 is attached to a side surface of the sensor probe 15.

Hall elements 18 which are magnetic field conversion elements are mounted near both ends of the stator 17.
Is arranged to face the magnet 5 when the mover 15 is located at the end of the moving area. Also, the stator
A rail-shaped position detection sensor 19 is provided on a side portion of the mover 15 at a position facing the sensor probe 16 of the mover 15.

Next, the circuit structure of the movable magnet type linear DC motor 14 will be described with reference to FIG. First, a CPU 20, which is a control circuit to which the position detection sensor 19 is connected, is connected to a drive IC 22 connected to each armature coil 11 of the stator 17 via a drive circuit 21, and these circuit components
A drive circuit 23 is formed by 21, 22. On the other hand, the comparator 25 to which the Hall element 18 and the reference voltage power supply 24 are connected is connected in parallel to the CPU 20 to an AND gate 26, and the AND gate 26 is connected to the drive IC 22 so that the circuit component 24 26 form an overrun prevention circuit 27.

In such a configuration, in the movable magnet type linear DC motor 14, a position detection signal is output from the position detection sensor 19 corresponding to the position of the sensor probe 16 attached to the mover 15, and based on the position detection signal, CPU20
Program-controls the drive IC 22. Then, this drive IC
The power supplied to each armature coil 11 from the drive circuit 21 by the drive circuit 21 is controlled, and the mover 15 performs operations such as moving and stopping in a predetermined direction.

The program control of the drive IC 22 by the CPU 20 includes, for example, a Start / Stop signal and a CW / CCW signal (Clock Wise / Count).
er Clock Wise) are output as Hi / Low signals.

Here, in the movable magnet type linear DC motor 14, for example, when the mover 15, which has become uncontrollable due to runaway of the CPU 20, moves to the vicinity of the end of the stator 17, the magnet 5 is detected by the Hall element 18. You. Therefore, the difference between the detection signal of the Hall element 18 that has detected the magnetic flux density of the magnet 5 and the reference voltage of the reference voltage power supply 24 is calculated by the comparator 25, and the calculated value is determined by the Hi signal and the Low signal according to detection and non-detection, respectively. Signal. Where the CPU is
Since the Start / Stop signal by 20 is also output as a Hi / Low signal, this signal and the output signal of the comparator 25 are combined by the AND gate 26 and input to the drive IC 22.

Therefore, the drive I controlled by the outputs of the comparator 25 and the CPU 20 of the movable magnet type linear DC motor 14
The output state of C22 is illustrated in the following table.

That is, in the movable magnet type linear DC motor 14, the output signal of the comparator 25 is always in the Hi state, so that the driving of the mover 15 is controlled by the CPU 20, and when the mover 15 moves to the end of the moving area, it is inevitable. Comparator 25
Becomes low, and the mover 15 stops regardless of the output signal of the CPU 20.

As described above, the movable magnet type linear DC motor 14 prevents overrun of the mover 15 by detecting the magnet 5 by the Hall element 18 on the bottom surface of the mover 15,
For example, when the stop position of the mover 15 is shifted due to a large inertia or the like, the magnet 5 is disengaged from above the Hall element 18, and the output signal of the comparator 25 becomes Hi state again,
There is concern that 15 runaways will resume.

Therefore, a holding circuit for holding the detection signal of the Hall element 18 is provided in the overrun prevention circuit 27 as described above, and the movable element 15 is provided.
It is conceivable to keep the stopping operation of. One such example is a comparator, as illustrated in FIG.
A circuit in which the FF circuit 28 is connected in the wiring from 25 to the AND gate 26 can be implemented. In this case, the output signal of the comparator 25 that has once been in the Low state by the FF circuit 28 is retained and output to the AND gate 26. Therefore, the mover 15 is reliably stopped irrespective of the stop position.

Next, an embodiment of the present invention will be described with reference to FIGS. 5 and 6. FIG. As shown in the drawing, the movable magnet type linear DC motor 29 has substantially the same structure as the movable magnet type linear motor illustrated in FIGS. 8 to 10, and is used for detecting excitation switching of the armature coil 11. Of the Hall elements 13, Hall elements 13a and 13b having higher sensitivity than the other Hall elements 13 are provided near both ends of the stator 3. These Hall elements 13a and 13b are connected to the comparator 25 of the overrun prevention circuit 27. In addition,
In the movable magnet type linear DC motor 29 of the present embodiment,
The Hall element 13 is arranged at the center of each armature coil 11.

In such a configuration, the movable magnet type linear DC motor 29 functions similarly to the above-described movable magnet type linear DC motor 14.

Here, this movable magnet type linear DC motor 29
Is a Hall element 13 used to detect the timing of excitation switching.
The overrun of the mover 15 is prevented by using the detected values of a and 13b. That is, the movable magnet type linear DC motor 29 of the present embodiment is, for example, provided with an overrun prevention circuit 27 including a comparator 25, an AND gate 26, and the like in an existing movable magnet type linear motor. This can be implemented by providing the Hall elements 13a and 13b having higher sensitivity than the Hall element 13, and it is possible to manufacture the movable magnet type linear DC motor 29 in which the overrun of the mover 15 is prevented with an extremely simple structure.

In addition, this movable magnet type linear DC motor 29 also
As illustrated in FIG. 7, the FF is included in the overrun prevention circuit 27.
By providing the circuit 28, overrun of the mover 15 can be reliably prevented.

According to the first aspect of the present invention, a stator in which a number of coils are continuously arranged in a longitudinal direction is provided, and a movable member movably disposed on the stator has N in the longitudinal direction of the stator. In a movable magnet type linear motor, a magnet facing the coil is provided alternately with poles S, a drive circuit for inputting a drive current to the coil of the stator is provided, and a control circuit for controlling the output of the drive circuit is provided. A magnetic field conversion element facing the magnet of the mover is mounted near both ends of the stator, and an overrun prevention circuit that regulates the output of the drive circuit connected in parallel with the control circuit in accordance with the detection of the magnet of the magnetic field conversion element. With this arrangement, even if the mover becomes uncontrollable due to runaway of the drive control circuit, etc., when the mover moves to the vicinity of the end of the stator, the magnetic field conversion element turns the magnet of the mover. The overrun prevention circuit operates by detecting the
Since the output of the drive circuit is regulated and the movement of the mover is stopped, the mover is prevented from overrun and the device is prevented from being damaged, and the overrun prevention circuit and the drive control circuit are connected to the drive circuit in parallel. In normal times, the driving of the mover is controlled by the drive control circuit, and the mover is stopped regardless of the output of the drive control circuit only when the device is abnormal, which hinders the performance in normal times. In addition, the invention described in claim 2 can improve the reliability of the device without using a stator in which a number of coils and a magnetic field conversion element for detecting the position of the mover are continuously arranged in the longitudinal direction. A magnet opposed to a coil and a magnetic field conversion element is mounted on a mover movably disposed on the stator in such a manner that the magnetic pole and the magnetic field conversion element are provided alternately in the longitudinal direction of the stator. Current And a control circuit for controlling the output of the drive circuit based on the detected value of the magnetic field conversion element. By providing sensitive magnetic field conversion elements and providing an overrun prevention circuit that regulates the output of a drive circuit connected in parallel with the control circuit in response to the detection of magnets of these highly sensitive magnetic field conversion elements, By providing a movable magnet type linear motor with an overrun prevention circuit, a movable magnet type linear motor with a mover overrun prevented can be obtained. This has the effect of, for example,

[Brief description of the drawings]

1 is a plan view showing an embodiment of the invention according to claim 1, FIG. 2 is a front view, FIGS. 3 and 4 are block diagrams, and FIG. 5 is an embodiment of the invention according to claim 2. 6 and 7 are block diagrams, FIG. 8 is a plan view showing a conventional example,
FIG. 9 is a side view, and FIG. 10 is a plan view. 2,15 ... mover, 3,17 ... stator, 5 ... magnet, 11 ... coil, 13, 18 ... magnetic field conversion element, 14, 29 ... movable magnet type linear motor, 20 ... control circuit, 23 ... drive circuit, 27… Overrun prevention circuit

Claims (2)

(57) [Claims] 1. A stator in which a number of coils are continuously arranged in a longitudinal direction is provided, and an N pole and an S pole are alternately arranged in a longitudinal direction of the stator on a movable member movably disposed on the stator. A movable magnet type linear motor, comprising: a magnet opposed to the coil, a drive circuit for inputting a drive current to the coil of the stator, and a control circuit for controlling an output of the drive circuit. A magnetic field conversion element facing the magnet is mounted near both ends of the stator, and an overrun prevention circuit that regulates the output of the drive circuit connected in parallel with the control circuit in accordance with the detection of the magnet of the magnetic field conversion element. A movable magnet type linear motor characterized by being provided. 2. A stator in which a number of coils and a magnetic field conversion element for detecting a position of a mover are continuously arranged in a longitudinal direction, and the fixed member is fixed to a mover movably disposed on the stator. N and S poles are alternately provided in the longitudinal direction of the child, and a magnet opposed to the coil and the magnetic field conversion element is attached,
In a movable magnet linear motor, a driving circuit for inputting a driving current to the coil of the stator is provided, and a control circuit for controlling an output of the driving circuit based on a detection value of the magnetic field conversion element is provided. A magnetic field conversion element having higher sensitivity than other magnetic field conversion elements is provided near both ends, and the output of the drive circuit connected in parallel with the control circuit in response to the detection of the magnets of these high sensitivity magnetic field conversion elements. A movable magnet type linear motor characterized by having an overrun prevention circuit for regulating.