JPH03135357A - Linear motor - Google Patents

Abstract

PURPOSE:To permit speed control by detecting the speed of a motor from a total motor current by a method wherein the winding specification of either one of coils is made different from the winding specifications of other coils, in the multi-phase linear motor. CONSTITUTION:The movable block B of a linear motor is a 3-phase block, in which three pieces of electromagnets 8, consisting of a laminated core 2, coils 3 wound around the core 2, and a brush 4, contacted slidingly with a power supply substrate 5, to which one end of the coil 3 is connected, are arranged in series. Current is supplied to two phases among 3-phase coils 3a-3c and the movable block B is advanced by obtaining a thrust force in one given direction by a magnetomotive force generated upon conducting said two phases. In this case, the winding specification of the coil 3 of one-phase electromagnet 8 among 3-phase electromagnets 8a-8c is made different from the winding specifications of the coils 3 of the other electromagnets 8. According to this method, a change, indicating the advancing speed of a motor, may be generated in a total motor current and the advancing speed may be controlled by detecting the change.

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF APPLICATION IN FILM INDUSTRY 1 The present invention relates to a linear motor used for conveyance.

[Prior Art 1] Recently, linear motors have been used for conveyance, and in this type of linear motor, current is selectively passed through a plurality of fills in accordance with the movement of a movable block. for example,
In a moving coil type linear motor with a three-phase mover block, as shown in Fig. 9, the same winding specification is used as the fills 3a-,'(c) of each phase of the mover block. , one end of the coils 3a to 3C of each phase is commonly connected, and power is supplied between the other ends of any two of the coils 3a to 3c, so that current always flows through the coils 3 of the two phases. .

[Problem to be solved by the invention 1 However, when multiple coils 3 with the same winding specifications as described above
A polyphase linear motor using
), when a current is constantly passed through the fill 3 of any two phases, each phase is called the U, V, and W phase. ),
As shown in FIG. 3(d), there is almost no change in the total motor current that indicates the moving speed of the mover block. Moreover, in the moving coil type linear motor, a power supply circuit for supplying power to the coils 38 to 3c is provided on the stator block side separated from the mover block, so each coil 3a to 3
It is difficult to detect the current flowing through either of the motors individually, and as a result, the only way to detect the traveling speed of the linear motor is from the output current of the power supply circuit, that is, the total motor current. Therefore, if the change in the total motor current is small as described above, it is difficult to detect the traveling speed of the linear motor from this motor current. There is a problem in that it is difficult to perform speed control such as detecting the speed of the linear motor or controlling the speed to be constant.

The present invention has been made in view of the above points, and an object thereof is to provide a linear motor that can perform speed control by detecting the speed from the total motor current.

[Measures for Solving the Problems\i1] In order to achieve the above object, the present invention makes the winding specifications of one of the fills different from the winding specifications of the other fills.

[Operation 1] By configuring as described above, the present invention allows a clear change to appear in the total motor current representing the traveling speed, and by detecting this change, it is possible to control the traveling speed. It is something.

[Example] An embodiment of the present invention is shown in FIGS. 1 to 8.

The linear motor of this embodiment is of a moving coil type, and has a structure in which a movable block Bfyt slides along a stator block A.

The stator block A includes a long base body 7 with a cross section L'F-, a long permanent magnet 1 disposed over the entire length of the horizontal piece 7a of the base body 7, and a vertical piece 7 of the base body 7. )] and a power supply board 5 that is attached to the inner wall surface of the mover block B and supplies power to the filter 3 of the mover block B.

As shown in Fig. 4, the permanent magnet 1 has a flat plate shape and is magnetized alternately to N and S poles at a constant pitch in the longitudinal direction, and also in the thickness direction as shown in Fig. 5(b) or (
As shown in c), it is magnetized to N and S poles. The permanent magnet 1 is attached to the horizontal piece 7a of the base body 7 by gluing or caulking. The length of a pair of magnet pieces consisting of an N pole and an S pole in the longitudinal direction of the permanent magnet 1 is L as shown in FIG. 4.

As shown in FIG. 5(, ), the power supply board 5 has an M section 5c that meanders vertically at a right angle at regular intervals in the center, and conductors 11s5a, 5b are connected to the upper and lower sections separated by the insulating section 5c.
It's Toshide. Then, a positive voltage is applied from the upper conductor part 5a to the fill 3 of the mover block B, which will be described later, and a negative voltage is applied to the coil 3 from the lower conductor part 5b. Here, each conductor portion 5a.

The width of the part protruding toward the center of 5b is L/3, and the insulating part 5C located between both conductor parts 5a and Sb
The width is L/6.

The mover block B includes an iron core 2 formed by laminating substantially U-shaped yoke, a coil 3 wound around this iron core 2, and one end of this coil 3 connected to the above-mentioned power supply board 5. It has a three-phase structure in which three electromagnets 8 each consisting of a brush 4 in contact with each other are arranged in a row. In addition, fl of coil 3! The lu ends are commonly connected as shown in FIG. And the base 7 of each electromagnet 8
The length along the longitudinal direction is not more than L/3. In other words, if the length of the iron core 2 along the longitudinal direction of the stator block A is Pl, then 1. <L/3, and the length of the electromagnet 8 when the filler 3 is wound is also set not to exceed /3 as described above. The interval between the brushes 4 provided for each electromagnet 8 and attached to the mover block B by an insulating plate 20 is L/3, and these brushes 4 are connected to the power supply shown by the dashed line in FIG. It contacts the center position of the substrate 4.

As shown in FIG. 3, the stator block A and movable block B are rectangular cylindrical pieces arranged in the idle rail 6, and an idle groove 9 is formed in the center of the lower surface of the idle rail 6 along the longitudinal direction. It is perforated. A connecting body 10 for connecting conveyed objects such as ornaments is integrally fixed to the mover block B, and a connecting piece 10m protruding from the connecting body 10 is inserted through the idle groove 9 of the idle rail 6. The movable block B is then housed within the guide rail 6. In addition, the connected body 1
Rollers 11 are provided on both sides of the mover block B to smooth the movement of the mover block B, and a slip plate 12 with a small friction coefficient can be attached to the part where the iron core 1 of the mover block B slides on the base 7. be. Further, the holes 16 formed in the connecting pieces 10& are for connecting objects to be transported.

In this linear motor, with the above-described structure, a current is constantly passed from the power supply board 5 to any two of the three-phase coils 3a to 3c, and the magnetomotive force generated at this time obtains a propulsive force in a fixed direction. The mover block 13 moves forward. In addition, when moving the movable block B in the opposite direction, the conductor portion 5m of the power supply board 5.

The polarity of the voltage of 5b may be reversed.

Incidentally, in this embodiment, the winding specifications of the coil 3 of the electromagnet 8 of one phase among the three-phase electromagnets 8a to 8c are different from the winding specifications of the coil 3 of the electromagnet 8 of the other phases. In the following explanation, a case will be explained in which the winding specifications of the coil 3b of the electromagnet 8b in FIG. 2 are different. In addition, in the following explanation, the electromagnet 88 (I phase, 8b is V phase, 8c is W phase)
6 (&) to () as in the conventional case.
As shown in c), pay 1! I can pass. In this case, specifically [
When the coil resistance of the 1-phase and W-phase fill 3a=3c is 2Ω, the coil resistance of the ■phase fill 3b is 8Ω, and the drive power supplied from the power supply board 5 is 24V, U
The motor current 11 when power is supplied to the -V phase and -W phase is 1, = 24/(2 + 8) = 2.4 (A), and U-W
The motor current ■2 when power is supplied to the phase is I, = 24/(2+2) = 6 (A). In other words, as mentioned above, any of the three phases h・1
By varying the winding specifications of the phase coils 3, the motor current changes in accordance with the traveling speed. Therefore, by detecting this periodic change, it is possible to control the speed of the linear motor.

An example of a power supply circuit that controls the speed of the linear motor is shown in FIG. 7. In this power supply circuit, the linear motor M
The traveling speed of the linear motor M is detected from periodic changes in the current flowing through the circuit, and a signal corresponding to this detection output is fed back to the control unit 14 of the switching power supply circuit 13 to keep the linear motor M at a constant speed. The constant speed control means 17 includes a current transformer T2, a waveform shaping circuit 15, a frequency/voltage conversion circuit (hereinafter referred to as an FV conversion circuit) 16, and a differential amplifier circuit A. It consists of 17. The current transformer T2 is connected in series with the linear motor M to the output of the switching power supply circuit 13, and the current transformer T2 controls periodic changes in the current flowing through the linear motor M, that is, the speed of the seven motors M. Detect. In addition, Figure 8 (
The current IN flowing through the linear motor M is shown in a), and the two major outputs v1 of the lance T2 have the signal waveform shown in FIG. 8(b). When these two outputs (■) are waveform-shaped by a waveform-shaping circuit 15 consisting of a comparator A2, a guiode D1, a resistor R7, and a reference voltage E2, the result is shown in Figure 8 (c).
A waveform shaped output v2 shown in is obtained. Then, the FV conversion circuit 16 converts the waveform shaped output V2 into a voltage signal VF according to the speed shown in No. 8 M(d). This voltage signal V
, is input to the differential amplifier circuit A, and is a speed setting voltage E whose voltage is WRg when varying the speed of the linear motor M.
The differential amplification output is input to the control terminal of the control unit 14.The control unit 14, to which the differential amplification output is input, adjusts the output tonnage according to the differential amplification output. The switching element Q is controlled to be turned on and off so that the speed of the linear motor M is kept constant at the speed set by the speed setting voltage E1. That is, in this power supply circuit, the speed of the linear motor M is detected by the constant speed control means 17, and a signal corresponding to this speed is fed back to the ll1lfRS14 of the switching power supply circuit 13, so that the linear motor M is controlled at a constant speed. It's Nishide.

Although the above explanation deals with constant speed control, it goes without saying that it can also be applied to speed control that variably adjusts the traveling speed, and the present invention may also be applied to fixed coil type linear motors. Effect 1 As described above, the present invention has the following advantages in a multiphase linear motor:
Since the @ wire specifications of one of the coils are different from the winding specifications of the other coils, it is possible to cause a change in the total motor current that represents the traveling speed, and by detecting this change, the traveling speed can be changed. can be controlled.

[Brief explanation of the drawing]

Fig. 1 is a front view of an embodiment of the present invention, Fig. 2 is a perspective view of the same as the above, and Fig. 3 is a perspective view when an idle rail is provided.
Figure 4 is a perspective view showing the structure of the main parts of the same as above, Figure 5 (a) is a front view of the power supply board, Figures (b) and (e) are explanatory diagrams showing the driving state of the movable block by the power supply board, Fig. 6 is an operation explanatory diagram showing the motor current as above, Fig. 7 is a circuit diagram of the power supply circuit, Fig. 8 is an explanatory diagram of the same operation as above, Fig. 9 is a connection diagram of the fill, and Fig. 10 is a conventional motor It is an explanatory diagram of electric current. A is stator block, B is mover block, 3a to 3C
is a coil.

Claims (1)

[Claims] (1) A multi-phase linear motor in which current is selectively passed through multiple coils according to the movement of a movable block, in which the winding specifications of one of the coils are different from the winding specifications of the other coils. .