JPH056440B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for driving a dual-rotation step motor.

[Prior Art] Conventionally, two coils are magnetically coupled to a stator having two main magnetic poles and one sub-magnetic pole, and driving pulses are applied to each coil separately.
Driving methods for rotating a step motor in both directions have been known. Furthermore, there is a known driving method in which a step motor having two coils is applied with a driving pulse whose voltage polarity is reversed while a driving pulse is applied to one coil of the other coil. was. For example, JP-A-54-8815
Such a structure is disclosed in Japanese Patent Application Laid-Open No. 15163/1983.

[Problem to be solved by the invention]

However, in the conventional method of driving a double-rotation step motor, the number of poles on the rotor must be multi-pole, and the operation cannot be stabilized unless the number of poles is two or the specifications of the two coils are precisely matched. I have an assignment.

Therefore, the purpose of this invention is to solve these conventional problems by creating a small, mass-producible, two-pole step motor that can stably rotate in both directions without having to precisely match the specifications of the two coils. The key is to get a good step motor.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic diagram of a step motor according to the present invention. The rotor 4 is a cylindrical magnet with two
It is polarized. The stator consists of main magnetic poles 1 and 2 and a sub magnetic pole 3, and the rotor facing angle a of the sub magnetic pole 3 is smaller than the rotor facing angle of the main magnetic poles 1 and 2.

There are two coils, 5 and 6. Coil 5 has main magnetic pole 2 and sub magnetic pole 3, and coil 6 has main magnetic pole 1 and sub magnetic pole 3.
are magnetically connected to each other. Both winding ends 7, 8, 9, and 10 of the two coils 5 and 6 are all connected to a drive circuit.

Figure 2 shows the rotation angle θ of the rotor 4 when not driven.
It is a graph showing potential energy. If there is no auxiliary magnetic pole 3 and the main magnetic poles 1 and 2 each have a rotor facing angle of 180°, the potential energy curve will have a substantially sinusoidal shape as shown by the broken line 11. When the sub magnetic pole 3 is present, it works to lower the peak value of potential energy at rotor rotation angles of 90° and 270°. However, sub magnetic pole 3
By appropriately designing the strength of the magnetic force on the rotor, it is possible to obtain a potential energy curve such as the solid line 12 that does not significantly disturb the sinusoidal shape. The stable positions of the rotor 4 are approximately 90° and 270° for such potential energy curves.

Next, Figure 3, Figure 4 a, b, c, Figure 5 a,
The driving method of the double-rotation step motor according to the present invention will be explained with reference to b, c, and d.

FIG. 3 shows an embodiment of the drive circuit. Inverters 14 , 15 , 16 , and 17 convert the drive pulse waveform generated by electronic circuit 13 into electric power and apply it to coils 5 and 6 . Figure 4a is an example of the voltage waveform applied to terminals 8, 7, 10, and 9 of coils 5 and 6, and b is the voltage waveform of terminals 8 and 10 based on terminals 7 and 9 in that case. be. Hereinafter, the drive pulse waveform will be illustrated in the format b. FIG. 4b shows the drive pulse waveform for clockwise rotation, and FIG. 4c shows the drive pulse waveform for counterclockwise rotation.

Next, the operation will be explained with reference to FIGS. 5a, b, c, and d. FIG. 5a shows the state at the time of the pre-pulse section 24 in which only the drive pulse for the coil 5 shown in FIG. 4b is rising. At this point, the main magnetic pole 1 and the sub magnetic pole 3 are the S pole, and the main magnetic pole 2 is the N pole, so the rotor 4
starts rotating in the right rotation direction (clockwise direction). FIG. 5b shows the time point of the main drive pulse section 25 in which the drive pulse is applied to both coils 5 and 6. At this point, main magnetic pole 1 has an S pole, and main magnetic pole 2 has an N pole.
A pole appears, and since no strong magnetic pole appears in the sub-magnetic pole 3, the rotor 4 continues to rotate further, and in the case of a two-pole rotor as shown in the figure, one step (180°) of rotation is completed.

In order to further rotate one step clockwise from this state, the polarity of the driving pulse may be reversed and applied as shown in FIG. 4b.

Figures 5c and 5d are examples of left rotation (counterclockwise) drive. The driving pulse waveform is shown in FIG. 4c. In this case, the coil 6 is first energized by the pre-pulse section 26, causing the rotor 4 to rotate counterclockwise.

In this manner, the direction of rotation can be determined by applying a voltage according to the pre-pulse section to either one of the coils.

FIG. 6 shows an embodiment in which the driving circuit and driving method are devised.

In particular, drive inverters 29, 30, 3 are installed in the IC.
1, this type of connection is advantageous because the area occupied by the driving inverter within the IC can be reduced. In this example, terminal 8 of coil 5 is connected to inverter 29, and terminal 9 of coil 6 is connected to inverter 31.
and terminal 7 of coil 5 and terminal 1 of coil 6
Both terminals 0 and 0 are connected to the inverter 30 and serve as a common terminal.

By providing a suitable logic circuit in the electronic circuit 28, it is possible to obtain clockwise rotation drive pulse waveforms and counterclockwise rotation drive pulse waveforms for the coils 5 and 6 as shown in FIGS. 4b and 4c. FIGS. 7a and 7b show an example of the voltage waveforms of the outputs 8 and 9 of the drive inverters 29, 30 and 31 and the drive pulse waveforms applied to the coils 5 and 6.

Next, a second embodiment of the drive circuit and drive method will be described.

In FIG. 8, an electronic circuit 40 and driving inverters 41, 42, and 45 are composed of C-MOSICs, and only the inverter 45 has gate inputs of a P-channel gate 43 and an N-channel gate 44 separated. ing. Therefore, by turning off both gates 43 and 44, the output can be placed in a high impedance state. FIG. 9 is a schematic diagram showing this driving method. In this example, the outputs of the three drive inverters 41, 45, and 42 are represented by H, L, and a high impedance state X.

In FIG. 9a, all three terminals are at "L" and no current flows during non-drive. Next, considering the case of performing clockwise rotation drive, as the pre-pulse section, Fig. 9b
When terminal 8 is set to "H" and terminals 7, 10, and 9 are set to "L", current flows only to coil 5. Next, as shown in FIG. 9c, by setting the terminals 7 and 10 to the high impedance state "X" while leaving the terminals 8 and 9 as they are, the current flows through the coils 5 and 6 and becomes the main drive pulse section. . As a result, after the rotor has rotated 180 degrees clockwise, if the conditions d and e in FIG. 9 are applied, the rotor will further rotate clockwise, making continuous clockwise rotation possible. FIGS. 9f, g, and i show the driving method for left rotation driving. The difference between the second embodiment and the first embodiment is that in the first embodiment, a voltage is applied to both coils in parallel during the main drive pulse period, whereas in the second embodiment, voltage is applied to both coils in parallel. The point is that a voltage is applied in series to the coil.

Next, FIG. 10 shows a specific embodiment of a double-rotation step motor according to the present invention.

The coil portion has a structure in which winding portions 51 and 52 are provided at two locations on a magnetic core 50 that is integrally formed of a high magnetic permeability material. A lead board 53 having a conductive pattern 54 is arranged between the two winding parts 51 and 52, and the ends of the windings are connected to this.

The stator portion 55 has an integral structure in which a pair of main magnetic poles 60, 61 and a sub magnetic pole 62 are connected by saturable narrow portions 56, 57, 58. The saturable narrow portion is magnetically saturated when the motor is driven, and the stator portion functions as three magnetically separated magnetic poles.

The rotor part is constituted by a permanent magnet 58 magnetized into two poles in the radial direction and a pinion part 59 for extracting rotational force, and is supported by tenon parts 63 and 64 provided above and below. The stator part and the coil part are magnetically coupled by tightening screws through three screw holes 60, 61, and 62, and furthermore, in the screw hole 61, the lead board having the terminal from the drive circuit and the coil lead board 53 face each other. The screws are then tightened and electrically connected.

The manufacturing technology for such a double-rotation step motor is
It has been established as a step motor for electronic watches, and uses samarium cobalt for the magnet material and permalloy material for the magnetic core and stator.The rotor diameter is 1 to 2 mm, the planar shape of the motor is 1 cm x 5 mm, and the thickness is 2.
With a size of about mm, it can be easily mass-produced.

〔Effect of the invention〕

As explained above, the present invention provides a step motor having a pair of main magnetic poles and one sub magnetic pole.
Two coils are connected in parallel or in series, and a driving pulse is applied to one coil, and the driving pulse is applied to the other coil after a predetermined time delay so that it is in the same direction as the magnetic flux generated by this driving pulse. Therefore, it has the effects described below.

Even without using a multi-pole rotor, a two-pole rotor allows the step motor to rotate in both directions.

The accuracy of matching the specifications of the two coils is not strict, and mass production is good.

A small double-rotation step motor is obtained.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram of a dual-rotation step motor according to the present invention, Fig. 2 is a graph showing the relationship between rotor rotation angle and potential energy, Fig. 3 is an example of a drive circuit, and Fig. 4 a, b, and c are graphs showing the relationship between rotor rotation angle and potential energy. Examples of coil terminal voltage waveforms and drive voltage waveforms; Figures 5a, b, c, and d are explanatory diagrams of the operation of a dual-rotation step motor; Figures 6 and 7a and b are examples of other drive circuits. Examples of coil terminal voltage waveforms and drive voltage waveforms, Figures 8 and 9a
to i are explanatory diagrams of an example of another drive circuit and a drive method, and FIG. 10 is a specific example of a dual-rotation step motor. 1, 2... Main magnetic pole, 3... Sub magnetic pole, 4... Rotor, 5, 6... Coil, 13, 28, 40... Electronic circuit, 14, 15, 16, 17, 29, 30,
31, 41, 42, 45... drive inverter,
24, 26... pre-pulse section, 25, 27...
Main drive pulse section, 50...Magnetic core, 51, 52...
...Winding part, 56, 57, 58...Saturable narrow part, 5
8... Rotor, 60, 61... Main magnetic pole, 62...
Sub magnetic pole.

Claims (1)

[Scope of Claims] 1. A rotor magnetized into two poles in the radial direction, a pair of main magnetic poles facing each other with the rotor interposed therebetween, and the strength of the magnetic force applied to the rotor is equal to the magnetic force of the main magnetic poles. a sub-magnetic pole smaller in strength than the main magnetic pole and provided substantially perpendicular to the main magnetic pole; a first coil magnetically coupled to one of the main magnetic poles and the sub-magnetic pole; and a second coil magnetically coupled to the auxiliary magnetic pole, the first coil and the second coil are connected in parallel, and the first coil or the second coil is connected in parallel. Applying a driving pulse to either one of the second coils, and applying the driving pulse so that magnetic flux in the same direction as the magnetic flux generated in the coil by the driving pulse is generated while the driving pulse is being applied. 1. A method for driving a dual-rotation step motor, characterized in that a drive pulse is applied to the other coil with a predetermined time delay after the start of application of the drive pulse. 2. A rotor magnetized into two poles in the radial direction, a pair of main magnetic poles facing each other with the rotor interposed therebetween, and the strength of the magnetic force on the rotor is smaller than the strength of the magnetic force of the main magnetic poles, and , a sub magnetic pole provided substantially perpendicular to the main magnetic pole, a first coil magnetically coupled to one of the main magnetic poles and the sub magnetic pole, another one of the main magnetic poles and the sub magnetic pole. a second coil magnetically coupled to a magnetic pole; the first coil and the second coil are connected in series, and either the first coil or the second coil Applying a drive pulse to one of the coils, at the time of starting application of the drive pulse so that a magnetic flux is generated in the same direction as the magnetic flux generated in the coil by the drive pulse while the drive pulse is being applied. 1. A method for driving a dual-rotation step motor, characterized in that a driving pulse is applied to the other coil with a predetermined time delay.