JPH09271161A - Stepping motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stepping motor which protects electric connection part members of a stepping motor such as coils, terminals, and lead wires, and enables to ensure electric connection of the coil to the electric connection part members. SOLUTION: A stepping motor 2 is equipped with the following; an annular bobbin 7 made of resin around which a coil 6 is wound, and outer yoke 8 and an inner yoke 9 which interpose the annular bobbin 7 and are provided with a plurality of magnetic teeth arranged in a cylindrical shape, a rotor 11 which is provided with a plurality of magnetic poles positioned in the central part of the cytlindrial magnetic teeth 8a, 9a, and has a rotary shaft 10, retaining plates 12, 13 provided with bearing parts 12a, 13a which fix the rotary shaft 10, and terminals 14 as electric connection part members which supply an electric signal to the coil 6. A protective part 12c for protecting the terminals 14 protruding toward the side part of the stepping motor 2 is integrally formed with the retaining plate 12.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a PM (permanent magnet).
The present invention relates to a stepping motor, for example, a stepping motor used as a movable part of an indicating instrument.

[0002]

2. Description of the Related Art A PM type stepping motor has been widely used as an actuator component in the field of office automation equipment, home electric appliances, automobiles, etc., and it is easy to control forward / reverse rotation and downsized depending on driving torque. Since it is also easy, in recent years, it has been attracting attention as a moving part of an instrument which replaces an air core type movement such as a cross coil type instrument.

Most of the PM type stepping motors are hollow, for example, as disclosed in Japanese Utility Model Laid-Open No. 5-72107, in which two coil-shaped annular bobbins are sandwiched between two pairs of annular yokes. Each of the corresponding annular yokes is provided by providing a cup-shaped stator having a portion and housing a rotor made of a permanent magnet having a rotating shaft in the hollow portion of the stator, and supplying an exciting signal to each coil. Exciting magnetic poles are formed on the plurality of pole teeth formed in the above, and the rotor is rotated in the forward and reverse directions by a predetermined pitch.

In order to supply an excitation signal (electrical signal) to each coil from a circuit board or the like, a terminal fixing portion is formed so as to project on a part of the annular bobbin of the stepping motor, and the terminal is fixed to this terminal fixing portion. It is provided. An excitation signal is supplied to each of the coils by electrically connecting to the circuit board via this terminal.

[0005]

By the way, in the stepping motor, the excitation signal is supplied to the coil by the exposed terminal formed by projecting radially outward from the cup-shaped stator. When an operator attaches the stepping motor to the circuit board or the like, the operator may touch the terminal and damage the terminal, and the stepping motor may be electrically connected to the circuit board. There is a risk that it will not be possible or that the stepping motor itself will be damaged.

Further, in a stepping motor using a lead wire instead of the terminal as disclosed in Japanese Utility Model Laid-Open No. 5-50987, for example, touch the vicinity of the connecting portion between the lead wire and the coil. Therefore, there is a possibility that the electrical continuity between the lead wire and the coil may be caused.

Therefore, the present invention provides a stepping motor capable of protecting the coil of the stepping motor and the electric connecting members such as terminals and lead wires and ensuring reliable electrical connection between the coil of the stepping motor and the electric connecting member. The purpose is to do.

[0008]

In order to achieve the above object, the present invention has a yoke provided with a resin-made annular bobbin around which a coil is wound, and a plurality of pole teeth which sandwich the annular bobbin and are arranged in a cylindrical shape. A rotor having a plurality of magnetic poles located at the center of the cylindrical pole teeth and a rotating shaft,
A stepping motor comprising: a supporting member having a bearing portion that supports the rotating shaft; and an electric connecting member that supplies an electric signal to the coil, the electric connecting member protruding laterally of the stepping motor. A protective portion for protecting the above is integrally formed with the support member.

Further, the supporting member provided with the protective portion is formed of an insulating member.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION A resin-made annular bobbin around which a coil is wound, a yoke having a plurality of pole teeth that sandwich the annular bobbin and are arranged in a cylindrical shape, and located at the center of the cylindrical pole teeth. A rotor having a plurality of magnetic poles and a rotating shaft, a supporting plate that is a supporting member that includes a bearing portion that supports the rotating shaft, a terminal that is an electrical connecting member that supplies an electrical signal to the coil, A stepping motor having a lead wire, wherein the coil and the terminal or lead are integrally formed with the support plate to protect the terminal or the lead wire protruding laterally of the stepping motor. Prevents disconnection from wires and protects the terminals and lead wires. It also prevents damage to terminals and lead wires themselves.

Further, since the protective portion is formed integrally with the support plate having the bearing portion, the terminals and the lead wires can be protected without increasing the number of parts.

Further, since the support plate is made of a resin material having an insulating property, even when the terminal or the lead wire comes into contact with the protective portion, the terminal portion and the lead wire are not connected to each other through the protective portion. It is possible to prevent a short circuit.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the accompanying drawings. In each of the embodiments, a stepping motor according to the present invention is used as a movable portion of a vehicle instrument.

FIG. 1 is a sectional view of a stepping motor of the first embodiment of the present invention, FIG. 2 is a top view of the stepping motor of the same embodiment, and FIG. 3 is a perspective view of the stepping motor of the same embodiment. FIG. 4 is a side view when the stepping motor of the same embodiment is used for a vehicle instrument.

FIG. 4 shows the case where the stepping motor according to the first embodiment of the present invention is used as a movable part of the instrument body in a vehicle instrument, and is composed of a speedometer for measuring and instructing the traveling speed of a vehicle such as an automobile. A stepping motor 2 that drives the pointer 1 in response to a signal from a speed sensor (not shown) and a design portion (not shown) such as scales and characters are formed, and the pointer 1 is rotated on the design portion. An instrument dial plate 3 that enables contrast reading, and a light guide 4 that guides and illuminates light from a light source (not shown) such as the pointer 1 and the design portion.
And a hard printed circuit board 5 located behind the stepping motor 2 and electrically connected thereto.

FIGS. 1 to 3 show a stepping motor 2 according to a first embodiment of the present invention. The stepping motor 2 includes a resin annular bobbin 7 around which a coil 6 is wound, and SEC and SPC. , Two stators A housed in outer and inner yokes 8 and 9 made of an iron-based metal material such as permalloy are coaxially arranged. Outer inner yoke 8, 9
Has a plurality of pole teeth 8a, 9a arranged in a cylindrical shape, and the pole teeth 8a, 9 are provided with a rotating shaft 10 at the center thereof and a plurality of magnetic poles are magnetized at a constant pitch. It has a rotor 11 consisting of. The rotor 11 includes support plates 12 and 13 which are a pair of support members for supporting the rotary shaft 10 of the rotor 11.

The annular bobbin 7 comprises a cylindrical winding portion 7a and a pair of disc-shaped winding guides 7b located at both ends thereof. Then, a terminal fixing portion 7c is formed by extending a part of the winding guide 7b to the outside, and the terminal fixing portion 7c is formed.
A metal terminal 14, which is an electrical connection member, is fixed to. This terminal 14 is provided with a current-carrying portion 14a extending parallel to the rotary shaft 10 for directly electrically connecting to the printed circuit board 5. An end portion (not shown) of the coil 6 is fixed to the terminal 14 by solder (not shown).

The outer and inner yokes 8 and 9 are composed of an outer yoke 8 formed in a substantially cup shape, and a substantially flat plate-shaped inner yoke 9 having an outer diameter slightly smaller than the inner diameter of the outer yoke 8 on the opening side. The outer and inner yokes 8 and 9 house the annular bobbin 7 inside the outer yoke 8 and
And the annular bobbin 7 are sandwiched between and. For this reason, the outer yoke 8 is provided with a cutout portion 8b for exposing the terminal fixing portion 7c and the terminal 14 to the outside of the outer yoke 8.

As described above, the two stators A having the annular bobbin 7 and the outer and inner yokes 8 and 9 are concentrically stacked on each other, and both opening sides of each outer yoke 8 are electrically welded to the center. A hollow portion S (see FIG. 1) is formed in
The rotor 11 is rotatably housed in the hollow portion S, and the rotor 11 is axially supported by the pair of support plates 12 and 13 through the rotating shaft 10.

The rotor 11 arranged in the hollow portion S of the stator A has a magnetic pole of the rotor 11 and an exciting magnetic pole of each coil 6 guided to each pole tooth 8a, 9a in response to a signal from the speed sensor. The rotating shaft 10 is driven by rotating the rotating shaft 10 by a predetermined pitch by the magnetic attraction and repulsion action of.

The support plate 12 is made of a synthetic resin material, and a bearing portion 12a for rotatably supporting the rotary shaft 10 is provided at the substantially center thereof.
Further, at both ends thereof, similarly, the tapping screws 15 are screwed into the rotary shaft 10 in the axial direction, and mounting portions 12b for fixing the instrument dial plate 3 and the light guide 4 are formed. (See Figure 4). The support plate 12 is integrally provided with a protective portion 12c that covers the terminal 14 protruding from the outer yoke 8. The protective portion 12c covers the terminal 14 from above, and is formed so that an operator does not touch the terminal 14 when handling the stepping motor 2. Therefore, when the stepping motor 2 is handled, the terminal 14 is not touched, the terminal 14 is not deformed, and the portion where the terminal 14 and the coil 6 are connected is not touched. It is possible to prevent disconnection between the coil 6 and the coil 6. The protection unit 1
Since 2c is formed of an insulating synthetic resin, the protective portion 1
Even if 2c is deformed and comes into contact with the terminal 14, the protective portion 12c
There is no short circuit between the terminals 14 via the.

The lower support plate 13 on one side is
It is made of a metal material, and is provided with a cylindrical metal bearing portion 13 a which substantially protrudes in the axial direction of the rotary shaft 10 and axially supports the rotary shaft 10 at substantially the center thereof.

As described above, according to this embodiment, the support plate 12
By forming the protective portion 12c and the mounting portion 12b with which the tapping screw 15 is screwed, the terminal 14 can be protected, and the supporting plate 12 (stepping motor 2) and the instrument dial plate 3, can be protected by the tapping screw 15.
It can be fixed to the light guide 4 (other member). Fixing to other members with the tapping screw 15 is the instrument dial 3
After fixing, the pointer 1 is fixed from the front to the tip of the rotating shaft 10 penetrating on the instrument dial plate 3. This is particularly useful for a stepping motor type instrument in which the stepping motor 2 is fixed to the printed board 4 after the instrument dial 3 is mounted.

FIG. 5 is a sectional view when the stepping motor 2 of the second embodiment of the present invention is used in a vehicle instrument,
In this embodiment, the support plate 13 is formed of a metal material, and in order to protect the terminal 14, the support plate 13 is integrally formed with a protection portion 13b extending upward. The protective portion 13b has a U-shaped cross section and surrounds the terminal 14. The support plate 13 is provided with a current-carrying portion 1 of the terminal 14.
It has a hole 13c through which 4a penetrates. Further, the mounting portion 12b of the upper support plate 12 extends in the same direction as the protective portion 13b and is assembled so as to cover the opening 13d of the protective portion 13b. The protective portion 13c protects the terminal 14 and also covers the support plate 12, so that the operator does not directly touch the terminal 14 and the terminal 1
It is possible to prevent damage to the coil 4, disconnection of the coil 6, and the like. Needless to say, the support plate 13 may be made of synthetic resin.

According to this embodiment, since the support plate 13 is formed with the protection portion 13b for protecting the terminal 14,
The terminal 14 is prevented from being damaged, and the portion where the terminal 14 and the coil 6 are electrically connected is protected, so that disconnection of the coil 6 can be prevented.

Since the gist of the present invention is to protect the electric connecting members such as the terminals 14 protruding laterally of the stepping motor 2, as in the third embodiment of the present invention shown in FIG. Is provided in the bobbin 7, the energizing portion 14a is extended in the same direction as the rotating shaft 10 and protrudes from below the stepping motor 2, is electrically connected to the circuit board 5, and is connected to the coil 6 protruding to the side. It goes without saying that a part of the terminal 14 may be protected.

The electrical connecting member is not limited to the terminal 14 only, and may be the lead wire or the like shown in the above-mentioned conventional example. In this case as well, the coil 6 and the lead wire are connected by soldering. The part can be protected and the same effect can be obtained.

In each of the above embodiments, the terminal 14 is projected laterally from the intermediate portion of the stepping motor 2. However, the invention is not limited to the above embodiments, and the electric connection member may be projected laterally. It goes without saying that the stepping motor 2 may be on the upper end side or the lower end side.

[0029]

As described in detail above, according to the present invention, a resin-made annular bobbin wound with a coil, a yoke having a plurality of cylindrically arranged pole teeth and sandwiching the annular bobbin, A rotor having a plurality of magnetic poles located at the center of a cylindrical pole tooth and having a rotating shaft, a supporting member having a bearing portion for supporting the rotating shaft, and an electrical connection for supplying an electric signal to the coil. A stepping motor provided with a member, wherein a protection portion for protecting the electric connecting member protruding laterally of the stepping motor is integrally formed with the support member, so that an electric connection can be made when the stepping motor is handled. Since the member is not touched, the electric connecting member is not deformed, and further, the portion where the electric connecting member and the coil are connected is not touched. It can provide a stepping motor which can also prevent disconnection of the coil.

Further, according to the present invention, since the supporting member provided with the protective portion is formed of an insulating material, even if the protective portion is deformed or comes into contact with the electrical connection member, the protective member is electrically connected via the protective portion. It is possible to provide a stepping motor that does not cause a short circuit between the connecting members.

[Brief description of drawings]

FIG. 1 is a sectional view of a stepping motor according to a first embodiment of the present invention.

FIG. 2 is a top view of the stepping motor of the embodiment.

FIG. 3 is a perspective view of a stepping motor of the same embodiment.

FIG. 4 is a side view when the stepping motor of the same embodiment is used in a vehicle instrument.

FIG. 5 is a sectional view of a stepping motor according to a second embodiment of the present invention.

FIG. 6 is a sectional view of a stepping motor according to a third embodiment of the present invention.

[Explanation of symbols]

 2 stepping motor 6 coil 7 annular bobbin 8 outer yoke 8a pole teeth 9 inner yoke 9a pole teeth 10 rotating shaft 11 rotor 12 support plate (support member) 12a bearing portion 12c protection portion 13 support plate (support member) 13a bearing portion 13b protection Part 14 terminal (electrical connection member)

Claims (2)

[Claims] 1. A resin-made annular bobbin wound with a coil,
A yoke having a plurality of pole teeth arranged in a cylindrical shape and sandwiching the annular bobbin, a rotor having a plurality of magnetic poles located in the center of the cylindrical pole teeth and having a rotating shaft, and the rotating shaft A support member having a bearing portion for axially supporting
A stepping motor comprising an electric connection member for supplying an electric signal to the coil, wherein a protection part for protecting the electric connection member protruding laterally of the stepping motor is integrally formed with the support member. A characteristic stepping motor. 2. The stepping motor according to claim 1, wherein the supporting member provided with the protection portion is formed of an insulating member.