JP2001317970A - Stepping motor, instrument using the stepping motor, and method of assembling the instrument - Google Patents

Abstract

(57) [Summary] [Problem] A problem at the time of press-fitting of the pointer can be solved.
To provide a stepping motor suitable for use in an instrument such as a vehicle instrument, an instrument using the stepping motor, and a method of assembling the instrument. SOLUTION: A stepping motor 50 according to the present invention includes a rotor 56 serving as a power source for driving an output shaft 57,
A stator 54, a coil 55 attached to the stator 54, and case members 51 and 52 that house the rotor 56, the stator 54 and the coil 55 are provided. Output shaft 5
7 has one end projecting from the upper surface of the case member 51 for attaching the pointer 20 and the other end 5.
7A2 is located on the same plane as the bottom surface 52c of the case member 52 or protrudes from the bottom surface 52c.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a stepping motor suitable for a vehicle, an instrument using the stepping motor, and a method of assembling the instrument.

[0002]

2. Description of the Related Art Conventionally, as a vehicle instrument, a cross-coil instrument has been generally used, and among the cross-coil instruments, there is a pointer-type instrument capable of holding a pointer position. In this type of needle, a bearing part is formed inside the instrument case for bearing of the pointer shaft (output shaft) to which the pointer is attached, and a silicon gel reservoir for regulating the rotation of the pointer is formed in the bearing part. Have.

[0003] On the other hand, a stepping motor is used as an actuator component of an instrument in the field of various OA equipment, home electric appliances and the like. As the cost of stepping motors has been reduced, stepping motors have also been used as actuator parts of vehicle instruments. For example, a vehicle is equipped with a vehicle instrument that displays measured values such as a vehicle speed and an engine speed. In this vehicle instrument, a stepping machine is used as an internal unit that drives a pointer disposed on the front of a dial. A motor is used.

Here, an example of a conventional vehicle instrument using a stepping motor will be described with reference to FIG.

FIG. 6 is a sectional view showing an example of the structure of a vehicle instrument using a conventional stepping motor. In FIG. 6, the vehicle instrument comprises a stepping motor 50 and a pointer 20 attached to a pointer shaft 57 as an output shaft of the stepping motor.

[0006] The stepping motor 50 has a case member having a mounting surface 52c mounted on a wiring board (not shown) of the instrument for a vehicle. This case member includes an upper case 51 and a lower case 52 made of synthetic resin, and the bottom surface of the lower case 52 corresponds to the mounting surface 52c. In addition, a rotor 56 serving as a power source for driving the pointer shaft 57 and a coil 55 fixed to the extending portions 54a and 54b of the stator 54 to excite the rotor 56 are accommodated in the case member. The pointer shaft 57 is formed of a metal member. One end of the pointer shaft 57 protrudes from the mounting hole 51c of the upper case 51, and the other end is fitted to the bearing 52e of the lower case 52.

The stepping motor 5 having the above structure
At the tip of one end of the zero pointer shaft 57, the pointer 20
Is mounted by press-fitting to form a vehicle instrument.

[0008] The stepping motor 50 to which the pointer 20 is attached is used as an instrument for the vehicle, and is provided with a lower case 5.
The terminals 55c and 55d protruding from the second mounting surface 52c are attached to the wiring board by penetrating one ends of the terminals 55c and 55d through through holes provided in the wiring board. Although a dial is arranged between the hands 20 and the stepping motor 50, it is not shown here.

[0009]

By the way, in a vehicle instrument using a cross coil type instrument or a stepping motor as described above, the attachment of the pointer to the pointer shaft is usually performed by press-fitting. When the case is made of synthetic resin which is easy to mold and inexpensive, the surface receiving the press-fitting load (for example, about 10 kg) when press-fitting the pointer is the bottom of the bearing portion of the synthetic resin case. For this reason, there is a problem that the bottom of the bearing portion may be depressed into a concave shape by receiving the press-fitting load, and the height of the pointer may change.

In order to solve such a problem, for example, it is conceivable to form the instrument case with metal instead of synthetic resin, but there is a problem that the cost is increased. Also,
Since the above-described needle-type cross-coil type instrument has a silicon gel reservoir, it is not possible to take measures to eliminate the inconvenience by working the bearing part or outside the case.

Accordingly, the present invention can solve the above-mentioned problem at the time of press-fitting of the pointer, and is suitable for use in an instrument such as a vehicle instrument, a stepping motor using the stepping motor, and an assembling of the instrument. It is intended to provide a way.

[0012]

According to a first aspect of the present invention, there is provided a stepping motor comprising: a rotor serving as a power source for driving an output shaft; a stator; A stepping motor including a coil attached to the rotor, the rotor, the stator, and a case member accommodating the coil.
The output shaft has one end protruding from the upper surface of the case member for attaching the pointer, and the other end is located on the same plane as the bottom surface of the case member or protrudes from the bottom surface. It is characterized by the following.

According to the first aspect of the present invention, a stepping motor includes a rotor serving as a power source for driving an output shaft, a stator, a coil attached to the stator, and a case accommodating the rotor, the stator, and the coil. And a member. The output shaft has one end protruding from the upper surface of the case member to attach the pointer,
The other end is located on the same plane as the bottom surface of the case member or protrudes from the bottom surface.

As a result, a stepping motor suitable for use in an instrument constituted by press-fitting the pointer into the output shaft is obtained.

According to a second aspect of the present invention, in the stepping motor according to the first aspect, the other end of the output shaft is provided with a portion protruding from a bottom surface of the case member to rotate the output shaft. It is characterized in that a rotation regulating portion for regulating is formed.

According to the second aspect of the present invention, the other end of the output shaft is provided with a rotation restricting portion for restricting the rotation of the output shaft at a portion protruding from the bottom surface of the case member. Therefore, when the pointer is pressed into the output shaft, the rotation restricting portion can be engaged with the engaging portion of the jig to restrict the output shaft from rotating, and the mounting angle of the pointer can be accurately determined. Can be.

According to a third aspect of the present invention, there is provided a gauge according to the first or second aspect, wherein a pointer is attached to one end of the output shaft of the stepping motor.

According to the third aspect of the present invention, a pointer is attached to one end of the output shaft in the stepping motor according to the first or second aspect. Thereby, a suitable instrument using the stepping motor is obtained.

According to a fourth aspect of the present invention, there is provided a method for assembling an instrument according to the third aspect, wherein the other end of the output shaft is placed on an upper surface of a jig. Press-fitting a pointer into one end of the output shaft.

According to a fourth aspect of the present invention, there is provided a method of assembling a meter according to the third aspect, wherein the other end of the output shaft is placed on the upper surface of the jig, and a pointer is provided on one end of the output shaft. And press-fitting. As a result, the bearing portion of the output shaft is not depressed, and an error in the press-fitting height of the pointer can be eliminated.

According to a fifth aspect of the present invention, in the instrument assembling method according to the fourth aspect, the step of placing the other end of the output shaft on the upper surface of the jig is formed on the upper surface of the jig. Engaging the rotation restricting portion with the engaging portion.

According to the fifth aspect of the present invention, the step of placing the other end of the output shaft on the upper surface of the jig includes the step of engaging the rotation restricting portion with an engaging portion formed on the upper surface of the jig. including. Therefore, when the pointer is pressed into the output shaft, the rotation restricting portion can be engaged with the engaging portion of the jig to restrict the output shaft from rotating, and the mounting angle of the pointer can be accurately determined. Can be.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which a stepping motor according to the present invention is applied to an instrument for a vehicle will be described below with reference to FIGS. In the present embodiment, the same or corresponding parts as those described in the description of the related art are denoted by the same reference numerals.

FIG. 1 is a perspective view showing the appearance of a stepping motor according to the present invention, FIG. 2 is an exploded perspective view of the stepping motor shown in FIG. 1, and FIG.
It is an expanded sectional view of the arrow direction which passes the -A line.

As shown in FIGS. 1 to 3, the stepping motor 50 includes an upper case 51 made of synthetic resin or the like.
And a lower case 52. The upper case 51 and the lower case 52 are positioned by fitting the corresponding fitting projections 52a of the lower case 52 into the pair of fitting holes 51a of the upper case 51, respectively. The hole 51b is engaged with and fixed to an engaging projection 52b provided on the outer wall of the lower case 52.

On the upper surface of the upper case 51, there are provided through holes 51c, 51c1 through which a pointer shaft (output shaft) 57 to be described later penetrates. On the side wall of the upper case 51, an arm-shaped hook 51e is provided.
Has an engaging portion that penetrates the wiring board 40 and engages with the surface thereof. The outer surface of the bottom plate constituting the lower case 52 is a mounting surface 52c fixed to the wiring board 40 of the vehicle instrument device, and the inner surface of the lower case 52 located on the back side of the mounting surface 52c is the first surface. 52d.

The lower case 52 further includes a bearing 52 e for rotatably fitting a pointer shaft 57, which will be described later, and a bearing 5.
Through hole 52e penetrating from 2e to mounting surface (bottom surface) 52c
1, a rotor bearing 52f to which one end of the rotor shaft member 53a is fixed, and a gear bearing 52g to which one end of the gear shaft member 53b is fixed. In addition, the lower case 5 of the rotor shaft member 53a and the gear shaft member 53b.
The part fixed to 2 is knurled to prevent the rotor shaft member 53a and the gear shaft member 53b from rotating.

The stator 54 is formed by laminating a plurality of (for example, three) metal plates made of, for example, a silicon steel plate or the like, and is formed in a frame shape corresponding to the shape of the lower case 52. Further, the stator 54 includes two rectangular extension portions 54a and 54b formed in a positional relationship orthogonal to the inside of the frame in order to mount the two coils 55.
Further, the stator 54 is provided with a hole 54c through which the gear shaft member 53b passes.

The coil 55 is made of a synthetic resin or the like, and has a coil bobbin 55a having a rectangular cross section at the center and having a through hole 55e, a coil wire 55b composed of a copper wire wound around the coil bobbin 55, and a coil bobbin. The terminals 55c and 55d are press-fitted into the terminal 55a and electrically connected to both ends of the coil wire 55b, that is, at the beginning and end of winding, by means such as soldering.

One end of each of the terminals 55c and 55d protrudes from a mounting surface 52d of the lower case 52 through a terminal through hole 52h provided in the lower case 52.

The rotor 56 is a drive source of the stepping motor 50, is formed of plastic and a magnet, and has a through hole (not shown) through which the rotor shaft member 53a passes. Also, the rotor 5
A rotor gear 56 a having a through hole connected to the through hole of the rotor 56 is mounted on the upper surface of the rotor 6.

The pointer shaft 57 is formed of a metal cylindrical member, and has through holes 51c, 51c of the upper case 51.
An upper small-diameter portion protruding from 1, an intermediate large-diameter portion 57A1 to which a pointer gear 57a made of, for example, plastic is fixed by press-fitting, and a lower small-diameter portion 57A2 penetrating from the through hole 52e1 to the bottom surface 52c of the lower case 52. Have. The step portion of the intermediate large-diameter portion 57A1 and the lower small-diameter portion 57A2 of the pointer shaft 57 is fitted into the bearing 52e of the lower case 52.

The gear 58 controls the rotation of the rotor 56 by the pointer shaft 5.
7, a large gear that is made of, for example, a synthetic resin and meshes with the rotor gear 56a of the rotor 56, and a small gear that meshes with the pointer gear 57a and has a smaller diameter than the large gear.

Next, the assembly of the stepping motor 50 will be described.

First, the extending portions 54a, 54 of the stator 54
b, the coil 55 is attached to each. Next, the rotor bearing 52f and the gear bearing 52 of the lower case 52
g, one end of the rotor shaft member 53a and one end of the gear shaft member 53b are attached. In this state, the gear shaft member 53b is positioned by penetrating the hole 54a of the stator 54, and the terminal 55 of the coil 55 is positioned.
c, 55 d through the terminal through-hole 52 h of the lower case 52 to allow the stator 54 to be connected to the lower case 52.
Attach to

Next, the rotor 56 is connected to the rotor shaft member 53.
a, and a pointer shaft 57 to which a pointer gear 57a is fixed is rotatably fitted to a bearing 52e of the lower case 52, and the lower case 5 is inserted through the through hole 52e1.
2 to the bottom surface 52c. Then, the gear 58 is rotatably attached to the gear shaft member 53b such that the large gear of the gear 58 meshes with the rotor gear 56a of the rotor 56 and the small gear meshes with the pointer gear 57a.

Next, the tip of the pointer shaft 57 is connected to the upper case 51.
And the other end of the shaft member 53a for the rotor and the other end of the shaft member 53b for the gear are provided on a second inner surface of the upper case 51 (not shown).
Fits. At the same time, the fitting projection 52a of the lower case 52 is fitted and positioned in the fitting hole 51a of the upper case 51, and the fitting hole 51b of the upper case 51 is
The upper case 51 and the lower case 52 are aligned and fixed by engaging with the second engaging projections 52b.

At this time, the upward movement of the pointer shaft 57 is caused by the upper small diameter portion and the middle large diameter portion 57A1 of the pointer shaft 57.
Is restricted by hitting the step portions of the through holes 51c and 51c1 of the upper case 51. Similarly, the pointer shaft 57
Is moved downward by the lower small diameter portion 57A of the pointer shaft 57.
2 and the step of the intermediate large diameter portion 57A1 are regulated by contacting the step of the bearing 52e of the lower case 52 and the step of the through hole 52e1, so that the pointer shaft 57 does not fall off the case member.

As described above, the stepping motor 5
0 is completed.

Next, the stepping motor 5 having the above structure
A method of assembling a vehicle instrument using 0 will be described.

First, the end of the lower small diameter portion 57A2 of the output shaft 57 projecting from the bottom surface 52c of the lower case 52 of the stepping motor 50 is placed on the upper surface 60a of a jig 60 made of metal or the like. Next, the pointer 20 is pressed into the tip of the upper small diameter portion of the output shaft 57 by applying an appropriate press-fit load (for example, 10 kg). As described above, a vehicle instrument in which the pointer 20 is attached to the pointer shaft 57 of the stepping motor 50 is completed.

In the above-described assembling method, the press-in is received by the jig 60 at the time of press-fitting the pointer, so that the step portion of the lower small-diameter portion 57A2 and the intermediate large-diameter portion 57A1 of the pointer shaft 57 is formed at the bottom of the bearing portion 52e. The bearing 52e is not depressed in a concave shape. Further, the height of the pointer 20 after the press-fitting is constant, and no error occurs.

In the vehicle instrument assembled as described above, the hook 51e provided on the side wall of the upper case 51 is attached to a mounting hole (not shown) of the wiring board.
Further, one end of each of the terminals 55c and 55d protruding from the mounting surface 52c of the lower case 51 is passed through a through hole provided in the wiring board, and the surface of the wiring board is brought into contact with the mounting surface 52c of the stepping motor 50. Fix it. And
The terminals 55c and 55d protruding from the rear surface of the wiring board are electrically connected by soldering.

The vehicle instrument attached to the wiring board is connected to terminals 55c, 5c through wiring patterns provided on the wiring board.
The electric signal corresponding to the measured amount is supplied to the coil 55, so that the rotation of the rotor 56 corresponding to the measured amount is transmitted to the pointer shaft 57 via the gear 58. Pointer 20 attached to the tip of pointer shaft 57
Is driven in accordance with the measured amount. Guideline 2
A dial is arranged between the zero and the stepping motor 50, but is not shown here.

As described above, the embodiment of the present invention has been described. However, the present invention is not limited to this, and various modifications,
Application is possible.

For example, in the above-described embodiment, the case where the stepping motor 50 is attached to the wiring board has been described. However, the present invention is not limited to this. It may be a plate, a light guide plate, a case, or the like.

In the above-described embodiment, the case where the mounting surface 52c of the stepping motor 50 is provided on the lower case 52 has been described. However, the present invention is not limited to this. It can be provided in the case 51.

In the above embodiment, the pointer shaft 57
The lower small diameter portion 57A2 of the lower case 52
c, but instead of this, the lower small diameter portion 5
The end face of 7A2 may be flush with the bottom face 52c.

In the above embodiment, the pointer shaft 57
Is formed of a cylindrical member, but as shown in FIG.
The lower small diameter portion 57A2 is formed in a semi-cylindrical shape, and a semicircular concave engaging portion 60b is formed on the upper surface 60a of the jig 60. The semi-cylindrical lower small diameter portion 57A2 is formed into a semicircular concave engaging portion 6A.
0b. In this case, the semi-cylindrical lower small diameter portion 57A2 serves as a rotation restricting portion that restricts the rotation of the pointer shaft 57, and the mounting angle of the pointer 20 to the pointer shaft 57 can be accurately determined.

The rotation restricting portion includes a lower small diameter portion 57A.
2 may be formed only in the portion protruding from the bottom surface 52c of the lower case 52. In addition, the rotation restricting portion 57A
The shape of 2 is not limited to a semi-cylindrical shape, and may be another shape.
Further, the shape of the engaging portion 60b is not limited to the semicircular concave shape, and may be another shape.

Further, the meter according to the present invention can be applied not only to vehicles, but also to other product fields such as various OA devices and home electric appliances.

[0052]

As described above, according to the stepping motor of the first aspect of the present invention, it is possible to obtain a stepping motor suitable for use in an instrument configured by inserting a pointer into an output shaft.

According to the second aspect of the invention, when the pointer is pressed into the output shaft, the rotation restricting portion is engaged with the engaging portion of the jig to restrict the output shaft from rotating. And the mounting angle of the pointer can be accurately determined.

According to the third aspect of the invention, a suitable instrument using a stepping motor can be obtained.

According to the meter assembling method of the present invention, the bearing of the output shaft is not depressed, and the error of the press-fitting height of the pointer can be eliminated.

According to the instrument assembling method of the invention, when the pointer is pressed into the output shaft, the rotation restricting portion is engaged with the engaging portion of the jig so that the output shaft is not rotated. The angle of the pointer can be accurately determined.

[Brief description of the drawings]

FIG. 1 is a perspective view showing the appearance of a stepping motor according to the present invention.

FIG. 2 is an exploded perspective view of the stepping motor of FIG.

FIG. 3 is an enlarged cross-sectional view taken along a line AA in FIG.

FIG. 4 is a cross-sectional view for explaining an example of a method of assembling an instrument using the stepping motor of FIG.

5A and 5B are diagrams illustrating another example of a method of assembling an instrument using the stepping motor of FIG. 1, wherein FIG. 5A is a partial cross-sectional view, FIG. 5B is a partial perspective view of a pointer shaft, and FIG. FIG. 2 shows a partial perspective view of a jig.

FIG. 6 is a cross-sectional view for explaining assembly of a vehicle instrument using a conventional stepping motor.

[Explanation of symbols]

 REFERENCE SIGNS LIST 20 pointer 50 stepping motor 51 upper case (case member) 52 lower case (case member) 54 stator 54 a extended portion 54 b extended portion 55 coil 56 rotor 57 pointer shaft (output shaft) 57 A2 lower small diameter portion (rotation restricting portion) 60 jig 60a upper surface 60b engaging portion

Claims (5)

[Claims] 1. A stepping motor including a rotor serving as a power source for driving an output shaft, a stator, a coil attached to the stator, and a case member accommodating the rotor, the stator, and the coil. The output shaft has one end protruding from the upper surface of the case member for attaching a pointer, and the other end is located on the same plane as the bottom surface of the case member or protrudes from the bottom surface. A stepping motor. 2. A rotation restricting portion for restricting rotation of the output shaft is formed at a portion protruding from a bottom surface of the case member at the other end of the output shaft. 2. The stepping motor according to 1. 3. An instrument according to claim 1, wherein a pointer is attached to one end of the output shaft in the stepping motor according to claim 1. 4. A method for assembling a meter according to claim 3, wherein the other end of the output shaft is placed on an upper surface of a jig, and a pointer is pressed into one end of the output shaft. A method for assembling an instrument, comprising: 5. The step of placing the other end of the output shaft on the upper surface of the jig includes the step of engaging the rotation restricting portion with an engaging portion formed on the upper surface of the jig. The method for assembling an instrument according to claim 4, wherein