JPH0530724A - Winding structure of stepping motor - Google Patents

Abstract

PURPOSE:To get a stepping motor which can prevent the abnormal operation even if wire breaking, etc., occur in one part of the connection line between the stepping motor and a driving circuit. CONSTITUTION:The windings 11 and 12 of a stator coil 1 are put in the bifilar winding in the same direction, and similarly the windings 13 and 14 of a stator coil 2 are put in the bifilar winding in the same direction. Either the winding starts or the winding ends of the two windings 11 and 12 on the side of the said stator coil 1 are connected to independent terminals 16 and 17, respectively, and similarly either the winding starts or the winding ends of the two windings 13 and 14 on the side of the stator coil 2 are connected to terminals 19 and 20, respectively, whereby those are excited by a bipolar driving method.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a stepping motor, and in particular, two stator windings arranged vertically in the axial direction of the rotor are bifilarly wound in the same direction, and a bipolar drive system is used. The present invention relates to a stepping motor that rotates a rotor by being excited.

[0002]

2. Description of the Related Art FIG. 5 is an exploded perspective view of a general PM type stepping motor of a bipolar drive system using a unifilar winding, which can increase output torque at a low drive frequency, and FIG. It is a circuit diagram of a motor. This type of PM stepping motor has a winding 29
A (see FIG. 6) and terminals 34 and 35, and winding 29B (see FIG. 6) and terminals 36 and 37 are molded into stator coils 47 and 48, respectively, and a large number of claw poles 3.
Two stators 32 and 33, which are composed of magnetic pole plates 38 and 39 having 8A and 39A and stator covers 40 and 41,
And a rotor 30 magnetized in multiple poles, and the stators 32 and 33 are installed in the axial direction of the rotor 30. Further, although not shown, there is also a bifilar winding / unipolar drive system that can obtain an output torque up to a high drive frequency as compared with the above-mentioned unifilar winding / bipolar drive system.

Next, the operation of the conventional stepping motor of unifilar winding / bipolar drive will be described.
When driving a stepping motor, first, a stepping motor drive device 31 including a power supply and a switching circuit is provided.
Connect each terminal of multiple connecting wires (wire harness) 43.
Connect to 44 and 45/46. Then, the windings 29A and 29 are driven by the stepping motor driving device 31.
B in a defined direction (for example, first the exciting coil 10
The A / 10B is switched in the X direction, the 10A is in the X direction as it is, and the 10B is in the Y direction. ) To flow the current in order. The current directions of the windings 29A and 29B are alternately inverted and excited with X and Y, and the rotor 30 rotates stepwise by a constant angle.

[0004]

However, in the conventional unifilar winding / bipolar drive type stepping motor, the terminals 34 and 35 connected to the windings 29A and 29B by an external force such as bending or pulling force.
・ 36 ・ 37 and connecting lines 43 ・ 44 ・ 45 ・ 46
Among them, if it is disconnected or broken at one place,
It could not function as a stepping motor at all. That is, in the conventional unifilar winding type, when the terminal or the connecting wire has a conduction failure even at one place, the exciting coil is not excited and the stepping motor malfunctions and the step amount of the rotor 30 is not determined. However, there is a problem that it becomes difficult to control the stepping motor. Further, in the conventional bifilar winding / unipolar drive stepping motor, the magnetic field is reversed by winding two windings in opposite directions. If the conduction failure occurs even at one place on the line, there is a problem that the control of the stepping motor becomes difficult. The present invention has been made to solve the above problems, and is capable of preventing an abnormal operation even if a disconnection or the like occurs in a part of a connecting line between a stepping motor and a drive circuit. The purpose is to obtain.

[0005]

A winding structure for a stepping motor according to the present invention is a PM in which a stator 3 having a stator coil 1 and a stator 4 having a stator coil 2 are installed in the axial direction of a rotor 7. In the stepping motor, the windings 11 and 12 of the stator coil 1 are bifilar wound in the same direction, and the windings 13 and 14 of the stator coil 2 are bifilar wound in the same direction. Either the starting end or the terminating end of the two windings 11 and 12 on the side is connected to the independent terminals 16 and 17, respectively, and either the starting end or the terminating end of the two windings 13 and 14 on the stator coil 2 side is similarly set. It is characterized in that each of them is connected to independent terminals 19 and 20 to be excited by a bipolar drive system. .

[0006]

In the present invention, the two windings of each stator coil 1 and 2 are bifilar windings in the same direction. Therefore, during normal operation, the 1 and 2 phase windings 11 and 12 of the stator coil 1,
And windings 3 and 4 of the stator coil 2 for three and four phases
A predetermined pattern (for example, first the exciting coils 10A and 10B are in the X direction, and then 10A is the same as the X direction).
In the direction, 10B is sequentially switched to four directions such as the Y direction. ), A current is flowing in one side of the stator coil 1, or even if one phase of one side of the stator coil 2 or three phases of one side of the stator coil 2 is disconnected due to a connecting wire or the like, the other two phase or four phase is magnetic. Excited according to the excitation pulse in the circuit,
Since the claw pole is magnetized, the stepping motor can be controlled without causing an abnormal operation.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a vertical side view of a bipolar driving stepping motor according to the present embodiment. The stepping motor includes a housing 5 made of synthetic resin, stators 3 and 4 having stator coils 1 and 2 molded in advance with synthetic resin or the like, a rotor 7, and a base 8. 4 is integrally fixed in the housing 5. The rotor 7 is provided with a rotor shaft 7A at its axial center, and a cylindrical rotor magnet 7B is attached to the outer peripheral portion, and both axial end portions of the rotor 7 are fixed inside the housing 5. It is rotatably supported by two bearings 6A and 6B. 8A is a circular hole provided in the center of the base 8 for inserting the rotor shaft 7A. In addition, FIG.
A perspective view of the stator coils 1 and 2 is shown, in which 15
Is a common terminal of the starting ends of the windings 11 and 12, and 16.
Reference numeral 17 is a terminal terminal. In addition, 18 is a winding 13.1
4 is a common terminal at the starting end of 4 and 19 and 20 are terminals at the terminating end.

Next, the structure of the stators 3 and 4 will be described in detail. However, since both have the same structure, the description of one stator will be omitted. As shown in FIG. 1, the stator 3 internally has an annular bobbin 9 having a U-shaped cross section, and the bobbin 9 has two phases of the stator coil 1 as shown in FIG. The (1 and 2 phase) windings 11 and 12 are wound in a bifilar winding in the same direction, and a common terminal 15 is connected to one end of each of the 1 and 2 phase windings 11 and 12 and the other. Terminals 16 and 17 are respectively connected to the terminals of and are excited by a bipolar drive system. The terminals 15, 16 and 17 are
Connecting wires 21, 22 ... to the stepping motor drive device 27
It is connected via 23.

[0009]

Operation of the embodiment In the stepping motor drive device 27, the switching transistors (not shown) are turned on / off to turn the windings 11, 12 and 3 of the 1 and 2 phases.
The current flows in the four-phase windings 13 and 14 according to the predetermined pattern as described above, and the current flows,
The rotor 7 rotates in steps. In this case, the 1 and 2 phase windings 11 and 12 and 13 and 14 of the 3/4 windings have the same resistance value R, and the windings 11 and 12 and 13 and 14 have currents in the same direction, respectively. Since the windings 11 and 12 and the windings 13 and 14 shown in FIG.
This is the same state as when replaced with a magnetic circuit such as A and 28B. Therefore, assuming that the current value I (A), the voltage E (V), and the resistance value R (Ω), the current value I flowing through the exciting coils 10A and 10B is I = E / (R ² / 2R) = (E / R) × 2. Here, for example, when one of the terminals 16, 17, 19, 20 and the connecting wire connected thereto is electrically disconnected, the windings of one stator coil 1 or stator coil 2 are connected in parallel. Therefore, only half of the current at normal times flows. However, even in this case, since the windings are bifilar windings in the same direction, the coil magnetic field can be reversed and the rotation of the rotor 7 can be controlled.
The decrease in motor output can be suppressed to 25%. Although not shown, the stepping motor driving device 2
7 is provided with a galvanic circuit for detecting a decrease in winding current due to disconnection, and when this signal is received, a program of a computer (not shown) in which the drive frequency is set to a low level is used. The stepping motor could be controlled almost in the same way. That is, the stepping motor of the present invention can operate even if one of the two windings wound around the stator coil 1 or 2 is broken. Further, in the above embodiment, the winding start of the winding is connected to the common terminal,
It is also possible to connect (not shown) to the drive circuit as independent terminals.

[0010]

As described above, the bifilar winding / bipolar drive type stepping motor according to the present invention is
Since the winding of each stator is an independent electric circuit and each stator is the same magnetic circuit, the motor output will drop slightly even if a part of the winding circuit breaks. The stepping motor can be controlled almost in the same way as before the disconnection by executing a computer program with a low drive frequency so that it is particularly suitable as a motor for a motor control device requiring reliability. It is something.

[Brief description of drawings]

FIG. 1 is a vertical sectional side view of a stepping motor of the present invention.

FIG. 2 is a perspective view of a stator coil of the present invention.

FIG. 3 is a circuit diagram showing a connection state between a stepping motor according to the present invention and a driving device thereof.

FIG. 4 is a simplified diagram showing the equivalent coil of FIG.

FIG. 5 is an exploded perspective view of a conventional stepping motor.

FIG. 6 is a circuit diagram showing a connection state between a conventional stepping motor and its driving device.

[Explanation of symbols]

1 Stator coil. 2 Stator coil.
3 Stator. 4 Stator. 5 housing. 7 rotor. 8 base. 9
Bobbin. 11 windings. 12 windings. Thirteen
Winding. 14 windings. 15 terminals.
16 terminals. 17 terminals. 18
Terminal. 19 terminals. 20 terminals. 21 connection line. 22 connection line.
23 Connection line. 24 connection lines. 25 connection lines. 26 connection line. 27 Stepping motor drive device.

Claims (1)

Claim: What is claimed is: 1. A PM type stepping motor, comprising a stator 3 provided with a stator coil 1 and a stator 4 provided with a stator coil 2 in the axial direction of a rotor 7. Windings 11 and 12 of the stator coil 2 are bifilar windings in the same direction, and windings 13 and 14 of the stator coil 2 are bifilar windings in the same direction.
· Either the start or the end of 12 is connected to the independent terminals 16 and 17, and similarly, the start or the end of the two windings 13 and 14 on the side of the stator coil 2 are independent terminals 19. A winding structure for a stepping motor, characterized in that the winding structure is connected to 20 and is excited by a bipolar drive system.