WO1998005114A1

WO1998005114A1 - Stepping motor

Info

Publication number: WO1998005114A1
Application number: PCT/JP1997/001701
Authority: WO
Inventors: Kouichi Satoh; Hiroyasu Numaya; Kouichi Jinushi
Original assignee: Nippon Seiki Co., Ltd.
Priority date: 1996-07-26
Filing date: 1997-05-20
Publication date: 1998-02-05
Also published as: JPH1042541A

Abstract

A stepping motor such that the smoothness of rotation of the rotor is improved. A first annular stator (1) is made up of an inner yoke (14), an outer yoke (13) and an annular bobbin (12) around which a coil is wound. A second annular stator (2) is made up of an inner yoke (24), an outer yoke (23) and an annular bobbin (22) around which a coil is wound. The two annular stators are joined concentrically. The rotor (4) is journaled in the hollow portion (S) in the stacked structure. Pole teeth (15, 16) each in a nearly trapezoid shape are so arranged like an annular comb, on the inner and outer yokes as to confront the rotor. Similarly pole teeth (25, 26) each in a nearly trapezoid shape are so arranged like an annular comb on the inner and outer yokes as to confront the rotor. The height (H) of each pole tooth is 75 to 90 % of the distance (HO) between the inner side surface of the inner yoke and the inner side surface of the outer yoke. The width (W1) of the root of each pole tooth is 60 to 80 % of the pitch (P) of the pole teeth. The width (W2) of the end of each pole tooth is 60 to 150 % of the thickness (T) of the inner and outer yokes.

Description

Description Stepping motor Technical field

The present invention relates to a so-called permanent magnet type stepping motor, and more particularly to a stepping motor useful as a movement of an analog indicating instrument. Background art

Conventionally, permanent magnet-type stepping motors have been widely used as actuator parts in the fields of equipment, home appliances, automobiles, etc. A stator and a rotor composed of a permanent magnet rotatably supported in the hollow of the annular stator, and a plurality of magnetic poles are provided on a peripheral surface of the rotor facing the annular stator. , S are alternately magnetized at a constant pitch, and the annular stator is formed with a plurality of pole teeth extending from the yoke into the hollow and facing the rotor magnetic poles in an annular comb-shaped arrangement with a constant pitch. A yoke including pole teeth is magnetized by supplying a pulse signal to the excitation coil, and the rotor is rotated by a predetermined rotation angle by a magnetic action between the pole teeth and the magnetic poles of the rotor. In addition, since it has various advantages such as high driving torque can be obtained despite its small size, in recent years, it has been attracting attention as a movement for an analog indicating instrument such as a speedometer or an engine tachometer. Is

By the way, when this type of stepping motor is used as a moving element of an analog indicating indicator, it is connected and fixed through a rotor, a pointer and a rotating shaft, and the rotor linked with the pointer is pulsed according to the measured amount. The force that can be driven by signal supply; the stepping motor also performs the operation of instructing the measured amount by the pointer connected to the rotor because the stepper motor steps the mouth according to the pole tooth hitch. Inevitably, it becomes step-wise = intermittent and behaves strangely. For this reason, when using a stepping motor as a movement of an instrument, as shown in JP-A-6-38497, it is necessary to directly connect the rotating shaft of the rotor and the pointer. Avoid using a speed reduction mechanism consisting of a plurality of gears between them, or as shown in JP-A-6-82271, a staircase-like pulse signal ( Voltage) is applied to each excitation coil to finely step-drive the rotor, so-called micro-step driving has been proposed.

However, the former using the speed reduction mechanism is disadvantageous in terms of productivity because the motor itself becomes larger and the number of parts increases, which is disadvantageous in terms of productivity. On the other hand, there are concerns about problems such as brushing. On the other hand, in the latter micro-step drive, the intermittent operation of the rotor (pointer) is visually observed by finely step-driving the mouth to a predetermined number of divisions. It is possible to alleviate the force to a level that does not cause discomfort due to the force; due to the imbalance of the magnetic circuit formed at each step between the magnetic pole of the rotor and the yoke including the pole teeth, etc. The rotational angular velocity of the rotor tends to vary at each step, and the smoothness of the rotor operation is not sufficient.To ensure sufficient smoothness, the excitation coil must be Need to correct the pulse signal waveform itself according to the rotor operation

The present invention has been made in view of these points, and its purpose is to improve the smoothness of the rotation operation of the rotor itself by devising the pole teeth structure of the yoke, and to move the analog-to-analog indicating instrument. In this case, it is possible to obtain the rotation of the pointer without feeling uncomfortable without using a deceleration mechanism, and when micro-step driving, stepping that requires almost no modification of the drive signal waveform DISCLOSURE OF THE INVENTION Which Does Not Provide a Motor The present invention provides a combination of two sets of inner and outer yokes, and first and second annular bobbins on which first and second excitation coils are wound, respectively. A rotor having a rotating shaft is rotatably supported in a hollow portion of a laminated body formed by concentrically laminating the annular stators, and the rotor is rotatably supported in each of the first and second annular stators. A plurality of pole teeth, which extend from the outer yoke into the hollow portion and are opposed to the rotor with an annular comb-like arrangement, are formed. The length of the pole teeth is determined by the length between the inner and outer yokes. Approximately 75 to 90% of the height dimension, the root width of the pole tooth is approximately 60 to 80% of the pole formation pitch, and the tip width of the pole tooth is approximately the inner and outer yoke plate thickness of approximately 6 to 80%. 0 ~! By setting (5)%, the smoothness of the rotation operation of the rotor is improved, and when used as a movement of an analog indicating instrument, a sense of discomfort can be felt even without a reduction gear mechanism. A smooth and highly accurate rotation of the pointer can be obtained without any need for correction of the drive signal waveform during micro-step driving.

1 is an external perspective view of a stepping motor according to an embodiment of the present invention, FIG. 2 is an exploded cross-sectional view of FIG. 1, FIG. 3 is a cross-sectional view of FIG. 1, and FIG. FIG. 5, FIG. 5 is a waveform diagram showing a waveform of a Hals signal supplied to an excitation coil, and FIG. 6 is a table showing a rotation operation characteristic of a rotor.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 1] is a perspective view of the outer appearance of the stepping motor according to the embodiment of the present invention, FIG. 2 is an exploded sectional view showing the internal configuration of FIG. 1, and FIG. 3 is a sectional view of FIG. In FIG. 2, the steering motor according to the present embodiment includes a first and second annular stators 1 and 2, a rotor 4 having a rotating shaft 3 as a center, and a rotatably supported shaft through the rotating shaft 3. The first, the first

Consists of two bearing flats 5, 65 In FIG. 2, a first annular stator 1 has a first annular bobbin 12 in which a first exciting coil 11 is wound in an annular shape and has a hollow inside, and an annular shape having a through hole in the center. A force-shaped outer yoke 13 formed on the inner yoke 13 and an inner yoke disposed on the opening side of the outer yoke 13 and having a through-hole in the center and formed in an annular flat plate shape] 4 And the third annular bobbin 1′λ is disposed in a housed state between the outer and inner yokes 13 and 14, so that the outer and inner yokes 13 and 14 have the thickness of the first rectangular bobbin i2. The outer and inner yokes 13 and 14 are provided with pole teeth 15 and 15 along the axial direction of the rotating shaft 3 of the rotor 4 on the periphery of each through hole. 16 are formed by a plurality of fixed hitches, and these pole teeth 15 and 1 are alternately combined in the hollow of the first annular bobbin 12 to form an annular comb-shaped arrangement. It has a row shape so that it faces the peripheral surface of the rotor 4.

The second annular stator 2 also has a structure similar to that of the first annular stator 1, and includes a second annular bobbin 22 having a second exciting coil 21 wound in an annular shape and having a hollow inside. A cup-shaped outer work 23 formed in an annular shape having a through hole in the center, and a flat plate having a through hole in the center and arranged on the opening side of the outer yoke 23. The second annular bobbin 22 is disposed in a housed state between the outer and inner yokes' 2: 5, 24, thereby forming the outer and inner yokes 2; , 24 are concentrically opposed to each other with an interval corresponding to the thickness of the second annular bobbin 22, and the rotation of the rotor 4 is also provided around the through-holes of the outer and inner yokes 2: 24. Axes: A plurality of poles 齿 25, 2 β are formed with a plurality of constant hitches along the axial direction of 3, and these pole teeth 25, 26 are alternately arranged in the hollow of the second annular bobbin 22. Braid And has an annular comb-teeth arrangement so as to face the peripheral surface of the rotor 4.

The first and second annular stators 1.2 are arranged along the axis of the rotation axis' 3 of the rotor 4 so that the inner casings 14 and 24 are adjacent to each other. As shown in Fig. 3, annular stators 1 and 2 having a hollow portion S at the center In this embodiment, the rotor 4 rotates the first and second cylindrical magnets 41 and 42 made of, for example, magnets in a concentric manner and separated from each other through a magnet holder 4. A plurality of magnetic poles extending in the axial direction of the rotating shaft 3 are alternately N and S at a constant pitch along the rotating direction on the peripheral surface of the first and second magnets 41, 42. The magnetic pole phases in the magnets 41 and 42 match each other:

The rotor 4 is housed in the hollow portion S of the annular stator 1 and 2 laminates,

The first and second bearing plates 5 and 6 fixed to the annular stators 1 and 2 are rotatably held through first and second bearing plates 5 and 6, and the magnetic poles of the magnets 41 and 42 are connected to the inner and outer yokes 13 respectively. , 14, 2, 2, 4 oppose the pole teeth 15, 16, 25, 26 with a predetermined space (see Fig. 3) _r —

FIG. 4 is an exploded view of the stators 1 and 2. In FIG. 4, the pole teeth 15, 16, 25, and 26 are all formed in the same isosceles trapezoidal shape. The inner and outer yokes facing each other in pairs in the annular stators 1 and 2], 4 and 13 and the pole teeth 15 and 1 based on the inner surfaces of the inner and outer yokes 2.4.23. The length 11 in the rotation axis 3 direction to the tip of 6, 25, '26 is the length between the inner surfaces of the paired inner and outer yokes 14, 1, 1a, 24, 2, 2, Ί. Root width in the rotating direction of the rotor 4 of the pole teeth 15, 16, 25, 26 set in the range of about 75 to 90% of the dimension H 0 and in the shape of an isosceles trapezoid Are the inner peripheral dimensions of the inner and outer yokes 14, 1, 2, 24, respectively. The pole teeth 15, 1 β, 25 at the inner, outer yokes] 4, 13, 24, 23 The formation hitch of the pole teeth 15, 16, 25, 26 obtained by dividing by the number η of Is set within a range approximate approximately 6 0-8 0% of the tooth forming arsenide pitch) I ^J (teeth formed arsenate pitch 1) = L / n), further, the pole teeth 1 5 was isosceles trapezoid , 16, 25, and 26, the tip width dimension W 2 of the rotor 4 in the rotation direction is 60 to 90 mm of the thickness T of the inner and outer yokes 14, 1 * 3, 24, and 23. 50% In this case, the pole tooth forming hitches I) of the pole teeth 15, 16, 25, 26 at each of the inner and outer yokes 14, 1: 5, 24, 23 are The arrangement phases of the pole teeth 15 and 16 and the pole teeth 25 and 26 constituting each set are shifted in the direction of rotation of the 2P rotor 4, and are further shifted by〗 / 2P. The arrangement phases of the pole teeth 15 and 16 and the pole teeth 25 and 26 (that is, the phases of the first and second stators 1 and 2) are shifted in the rotation direction of the rotor 2P. Therefore, the farthest pole tooth 1Γ> and the pole tooth 26 will be displaced in the rotation direction of the rotor 4 by 1 / 4Ρ.

In the stepping motor of this embodiment having such a configuration, a drive circuit (not shown) supplies a Hals signal (voltage) having a waveform as shown in FIG. 5, for example, to the first and second excitation coils 11.2.11. This Hals signal is generated by a mechanical step operation (mechanical operation) determined by the pitch Ρ of the pole teeth 15, 16, 2, 2 of the outer and inner yokes 12, 1, 23, 24. SIN and COS waveforms, which are typical approximate waveforms for operating a micro-step (a rotation angle obtained by dividing a mechanical rotation angle into a predetermined number) by so-called micro-step driving The micro-step drive enables the rotor 4 to rotate in the forward and reverse directions at a predetermined rotation angle determined according to the number of divisions. Fixed and drive circuit By performing micro-step drive according to the measured amount of both speeds, etc., it can be used as a movement of an analog instrument

Here, the shape of the pole teeth 15, 1, 25, 26 at each of the inner and outer yokes 14, 13, 24, 2. 590% Dimension W 1 = Pole Tooth Hitch PX 608 ()%, Dimension W '2 Thickness TX 6 0 15 ()% In order to make the rotor 4 rotate smoothly, prepare several types of inner and outer yokes 14, 13, 24, 23 with different dimensions ti, H 0, W 1, W 2. Can be obtained by comparing and verifying each of these combinations in experiments. According to such an experiment, as shown in FIG. 6, the rotation characteristics of the rotor 4 were such that the shapes of the pole teeth 15, 16, 25, and 26 were H = H 0 X 75 to 9. 0%, W 1 = I) X 60 to 80%, W 2 = TX 6 () to 150%, the smoothness was found to be less than 0%. The smoothness (%) shown on the middle and vertical axes means that the (rotation) angular velocity (deg / sec) of the pointer is measured by fixing an optical rotary encoder to the rotating shaft 3 through experiments. Rotor 4) Calculate the average angular velocity per rotation (this value is A) and the guideline: σ (standard deviation value) of the angular velocity distribution during the rotation (this value is 、). ΒΖValue Λ X〗 () This value is calculated using (0). This value (%) Power: The smaller the force, the higher the smoothness becomes. And the value of the smoothness of 10% or less is, for example, rotation. Axis The Sutetsu ping motor mounted guidance when used as a Ana port grayed formula indicating instrument for Mubume emissions Bok, Ru der which a measure (lower limit) that does not feel uncomfortable with rotation of the pointer.

As described above, in this embodiment, two sets of inner and outer yokes〗 4,〗 3, 24, 23 and the first and second excitation coils 11, 12 are wound. The first and second annular stators 1 and 2 are provided in combination with the first and second annular bobbins 12 and 22, and the annular stators 1 and 2 are concentrically laminated. A rotor 4 having a rotating shaft 3 is rotatably supported in a hollow portion S of the body, and inner and outer yokes 14, 13, 24, 2 are respectively mounted on the first and second annular stators 1, 2. A plurality of pole teeth 15, 16, 25, 26, which extend in the hollow part S from 3 and are opposed to the mouth 4 with an annular comb shape arrangement, are formed. Length dimension 内 for inner and outer yokes 14, ：: Length between inner surfaces of 24, 23 Approximately 75% to 90% of Η0, pole teeth 15, 16, 25, 26 The root width W1 of the pole teeth is approximately 60 to 8 ()% of the pole tooth formation hitch Ρ, pole teeth 15, 1β, 25, By setting the tip width dimension W2 of 26 to approximately 60 to】 50% of the plate thickness dimension of the inner and outer yokes 14, 1, 24, and 23, the rotation of the rotor 4 is smooth. And the movement of the analog indicating instrument In the case of using a micro-step, it is possible to obtain a smooth and accurate rotation of the pointer without a sense of incongruity without using a deceleration mechanism. Industrial availability that can reduce the need for

As described above, the present invention has been described using a two-phase or four-phase permanent magnet type stepping motor as an example. However, the present invention is not limited to this, and a single-phase or four-phase or more multi-phase permanent magnet type stepping motor is used. It can be applied to the structure of

Claims

The scope of the claims

1. A first annular stator comprising an annular inner yoke and an outer yoke concentrically opposed to each other at a predetermined interval so as to form a magnetic path of a first exciting coil wound annularly; A second annular stator consisting of an inner ring and an outer ring which are concentrically opposed to each other at a predetermined interval so as to form a magnetic path of the rotated second excitation coil; The first and second annular stators are concentrically stacked so that the inner yokes are adjacent to each other. The permanent magnets are rotatably supported through a rotating shaft in a hollow portion of a stator laminate formed by a rotating shaft. A plurality of rotors each extending from the inner and outer yokes in the hollow portion along the axial direction of the rotor on each of the first and second annular stators. The substantially trapezoidal pole teeth facing the rotor The axial lengths up to the tip of the pole teeth with respect to the inner surfaces of the inner and outer yokes facing each other in the first and second annular stators are opposed to each other. It is set to approximately 75 to 90% of the length between the inner surfaces of the inner and outer yokes, and the root width and tip width of the substantially tooth-shaped pole teeth along the rotation direction of the rotor are set. In each case, the root dimension is about 60 to 8 ()% of the pole tooth forming hit in each of the inner and outer yokes, the tip width is each 內, and the thickness of the outer yoke is 6 () to 150 (50). %, Which is set to%