JPS61116962A - linear motor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a moving coil type linear motor using permanent magnets with high coercive force.

Conventional configurations and their problems In recent years, the production tact of production equipment has also been speeded up. For this reason, many drive devices utilize IJ near motors. Conventionally, when this linear motor was used in a vertical positioning mechanism, the moving parts of the linear motor were affected by gravity, which caused problems such as the control surface due to weight, the control circuit becoming complicated, and the power consumption of the other control circuit increasing. There were drawbacks.

Hereinafter, a conventional spring-based quad balance type linear motor as described above will be explained with reference to FIG.

In Fig. 1, 1 is an outer fixed core forming a magnetic path, 2
3 is a ferromagnetic material, and 4 is a center pole forming a magnetic path.
(・Bobbin, 5 is a coil wound around the bobbin 4, 6 is a weight balance spring for balancing the gravity of the entire movable part, 7 is a load weight, 8 is a guide roller that holds the bobbin/4t.

The operation of the +7 near motor configured as above will be explained below. First, the load weight 7 attached to the coil of the linear motor is controlled by the control method shown in Fig. °il 11
A current is applied to generate driving force and positioning. By detecting the positioned position with the position sensor 12, highly accurate positioning can be performed.

However, in the above configuration, weight balance is performed by a spring, and as the spring expands and contracts, the weight balance force changes in proportion to the position, as shown in FIG. Therefore, the current flowing through the coil for driving is inefficient because it not only drives the load weight, but also has to flow a driving current to cancel the reaction force of the spring. Further, since the reaction force generated by the spring is stopped by the extension of the spring, there is a drawback that the control circuit becomes complicated and adjustment becomes difficult.

Purpose of the Invention The present invention solves the problems of the conventional example described above, simplifies the mechanism (weight balance mechanism), and simplifies the mechanism (weight balance mechanism).
The present invention provides a linear motor that can reduce the control capacity of the motor.

Structure of the Invention The IJ near motor of the present invention includes a center pole made of a ferromagnetic material formed into an angular shape, inner and outer fixed cores arranged on the left and right sides of the center pole with a gap in between, and both ends of the inner and outer fixed cores and the above. A magnetic circuit is composed of a magnetic end plate that magnetically connects the center pole and a permanent magnet attached to the outer fixed core, and a control coil and a weight balance coil that aims to cancel the gravity applied to the load. is provided so as to be movable in the axial direction of the center pole. With this configuration, the spring 6 shown in FIG. 1 of the conventional example can be deleted, the power of the control amplifier due to the increase in load conditions due to the weight balance spring can be reduced, and the linear motor control circuit can be simplified.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 4 shows the structure of a linear motor in one embodiment of the present invention. In FIG. 4, 14 is an outer fixed iron core, 1ε is a center pole, 16 is a permanent magnet, 17 is a bobbin that drives up and down, 18 is a weight balance coil,
19 is a control coil, 20 is a load weight, and 21 is a roller that guides the load. FIG. 6 shows a control circuit for driving this linear motor. In FIG. 5, 22 is a weight command input terminal, 23 is a weight balance control coil amplifier, 25 is a position command input terminal, 26 is a linear motor control coil amplifier, and 28 is a position detector.

The operation of the near motor configured as described above will be explained below. Load weight 20 and bobbin 17 in Figure 4
A weight command current is input to terminal 22 so as to maintain a balance with the gravity applied to the terminal.

The input current is amplified by the amplifier 23 and supplied to the weight balance coil 18, so that the load weight 2Q is balanced with gravity, and becomes an apparent weight Og with respect to the control coil 19 of the linear motor.

Next, a positioning command current is supplied to the terminal 25 in order to position it to a free position above and below. The input current is amplified by the amplifier 26 and supplied to the control coil 19,
Positioned to the commanded position.

With the above configuration, the weight balance used in the conventional example is deleted. Also, the increase in power of the control amplifier due to uneven reaction force due to the weight balance spring is eliminated, and control efficiency can be improved. .

Effects of the Invention As described above, the present invention has a center pole made of a ferromagnetic material formed into an angular shape, inner and outer fixed cores arranged on the left and right sides of the center pole with a gap in between, and both ends of the inner and outer fixed cores. A magnetic circuit is composed of a magnetic end plate that magnetically connects the center pole with the permanent magnets attached to the outer fixed core, and a control coil and a weight balance coil for weight balance. By providing the center pole so as to be movable in the axial direction, a spring for balancing the weight with the load weight to be positioned becomes unnecessary. Furthermore, the power increase of the control amplifier due to non-uniform reaction force due to the positioning location of the weight balance spring is eliminated and the efficiency is increased, so the practical effect is significant.

[Brief explanation of the drawing]

Fig. 1 is an overall configuration diagram of a conventional linear motor with a weight balance spring, Fig. 2 is a control block diagram of a conventional linear motor, Fig. 3 is a characteristic diagram of a QUITE balance spring, and Fig. 4 is an embodiment of the present invention. Overall configuration diagram of a linear motor showing an example,
FIG. 6 is a control block diagram of an embodiment of the present invention. 18... Weight balance coil, 19...
... Control Koinope 23 ... QUITE balance amplifier, 26 ... Control coil amplifier, 28 ...
...Positioning detector. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Figure 〆θ Figure 3 Buff 0 Ishin v: (πm) i4 Figure 15, Figure 5

Claims (1)

[Claims] A center pole made of a ferromagnetic material formed into an angular shape, inner and outer fixed cores arranged on the left and right sides of the center pole through a gap, and a magnet that magnetically connects both ends of the inner and outer fixed cores to the center pole. The end plate and the permanent magnet attached to the outer fixed core constitute a magnetic circuit, and a control coil and a weight balance coil for weight balance are movable in the axial direction of the center pole. motor.