JP2003333793A - Motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a motor in which lubricant is secured permanently and smooth rotation is guaranteed for a long term while reducing the rotation sound over a long term. <P>SOLUTION: A boss 28 is formed on the bottom face of a case body 12 and the forward end part of a supporting shaft 16 is press fitted in a recess existing in the center of the boss 28 thus securing the supporting shaft 16. An annular wall part 30 is formed to project upward at the outer circumferential part of the boss 28. An oil storing part exists in the wall part 30 and lubricant is stored therein. A rotor 18 having permanent magnets 20 arranged on the outer circumferential side is supported by the supporting shaft 16 while engaging with the supporting shaft 16 rotatably. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor which is miniaturized and can operate smoothly, and is suitable for a two-phase electric motor such as a stepping motor for a meter mounted on a vehicle.

[0002]

2. Description of the Related Art Generally, an analog type meter mounted on a vehicle and displaying an analog signal has a pointer driven by a cross coil motor. However, in recent years, this has been replaced by an improvement in pointing accuracy and size reduction. Another type of motor, the stepping motor, has been adopted.

That is, as a stepping motor for an on-vehicle meter, for example, one described in Japanese Patent Publication No. 11-501800 is known. The conventional stepping motor disclosed in this publication is a permanent magnet in which a plurality of magnetic poles are continuously magnetized along the circumferential direction on the outer peripheral side of a rotor 112, which is a rotor, as shown in FIGS. Not only the magnet 118 is attached, but also the exciting coil 116 is attached to the two supporting portions 114A and 114B provided on the magnetic yoke 114 which is a stator arranged around the rotor 112.
A and 116B are provided respectively.

[0004]

The operation of the stepping motor is as follows. First, as the rotor 112 having the support shaft 130 supported by the boss 132 rotates,
The rotation of the driving gear 122 attached to the rotor 112 is transmitted to the output gear 126 via the intermediate gear 124, and the output shaft 128 of the stepping motor rotates in a decelerated form. That is, when this stepping motor is used for a vehicle-mounted meter, reduction of rotation noise and smooth operation are particularly required in such applications, so that the driving gear 122, the intermediate gear 124, and the output gear 1 are required.
It was necessary to apply lubricating oil to the bearing portions that support the respective 26.

On the other hand, in the case of a motor for a vehicle-mounted meter, -4
It is generally required to operate reliably in a wide temperature range from 0 ° C to + 105 ° C, and it is necessary to select a lubricating oil with low viscosity in order to ensure smooth operation even at a low temperature of -40 ° C. Had. However, when such a low-viscosity lubricating oil is used, when the temperature becomes high, for example, about + 105 ° C., the viscosity becomes unnecessarily low and the lubricating oil may spread on the surface of the case. Then, as the lubricating oil gets wet and spreads, the amount of oil decreases, and as a result, there is a drawback that the rotation noise becomes loud.
Incidentally, this defect was particularly remarkable in the bearing portion of the rotor 112 that rotates at the highest speed.

In view of the above facts, an object of the present invention is to provide a motor capable of permanently securing a lubricating oil, reducing a rotating sound for a long period of time, and ensuring a smooth rotation operation for a long period of time. .

[0007]

According to a first aspect of the present invention, there is provided a motor including a housing provided with a shaft mounting portion, a support shaft having one end fixed to the shaft mounting portion of the housing, and a support shaft rotatably engaged with the support shaft. A rotating body whose one end is supported by the shaft mounting portion of the housing while being assembled,
And an annular wall portion which is arranged on the outer peripheral portion of the shaft mounting portion and stores the lubricating oil.

The operation of the motor according to claim 1 will be described below. According to the present invention, one end side of the support shaft is fixed to the shaft mounting portion provided on the housing, and the one end of the rotating body is rotatably engaged with the support shaft while the one end of the rotating body is mounted on the shaft mounting portion. Supported by. Further, an annular wall portion for storing lubricating oil is arranged on the outer peripheral portion of the shaft mounting portion.

Therefore, the annular wall portion is arranged around the support shaft fixed to the shaft mounting portion of the housing, and the lubricating oil is stored in this wall portion, so that the operation is performed at a low temperature. Even if a low-viscosity lubricating oil is selected to ensure
From the low temperature to the high temperature, the lubricating oil is reliably dammed up by the wall, preventing it from getting wet and spreading on the surface of the housing.
As a result, the amount of oil in the bearing portion of the rotating body does not decrease, so that the rotation noise of the rotating body does not increase and smooth rotation of the rotating body is not hindered. As described above, the motor according to the present invention can permanently secure the lubricating oil, reduce the rotation noise of the rotating body for a long period of time, and ensure a smooth rotation operation for a long period of time.

The operation of the motor according to claim 2 will be described below. This claim has the same structure as that of claim 1 and operates in the same manner. However, in this claim, the rotating body is a rotor in which permanent magnets are arranged on the outer peripheral side and gears are arranged at the ends. It is configured to In other words, when the motor has a gear train for deceleration, by applying this claim to a rotor having a permanent magnet that rotates at the highest speed, lubricating oil is permanently applied to the bearing portion of this rotor. The rotation noise of the rotor can be reduced and the smooth rotation operation can be ensured for a long period of time.

The operation of the motor according to claim 3 will be described below. This claim has the same structure as that of claim 1 and operates in the same manner. However, in this claim, the lubrication is formed at the distal end portion of the annular wall portion so as to project toward the inner peripheral side. The oil spill prevention piece is provided. Therefore, by providing the lubricating oil outflow prevention piece that protrudes toward the inner peripheral side at the tip of the annular wall portion, it is possible to more reliably prevent the lubricating oil from leaking out of the wall portion, and The oil can be held in the bearing portion of the rotating body more reliably.

[0012]

DETAILED DESCRIPTION OF THE INVENTION A first embodiment of a motor according to the present invention will be described below with reference to the drawings.
The present invention will be clarified. As shown in FIGS. 1 to 4, a case body 12 made of a synthetic resin constitutes a casing which is an outer frame of a stepping motor 10 which is a motor according to a first embodiment of the present invention. A lid member 14 made of synthetic resin also constitutes the lid of the main body 12. These lids 1
The end portions of the support shafts 16 are fitted to and supported by the same parts of the casing 4 and the case body 12, respectively, and the support shafts 16 are hung between them.

That is, as shown in FIG. 4, the case body 1
A boss 28, which is a circular shaft attachment portion, is provided on the bottom surface of the support shaft 16. The tip end portion of the support shaft 16 is press-fitted into the recess 28A existing in the center of the boss 28 to fix the support shaft 16. . An annular wall portion 30 is formed on the outer peripheral portion of the boss 28 so as to project upward. Therefore, an oil storage portion 32, which is a space, is present in the annular wall portion 30 arranged around the portion of the case body 12 to which the support shaft 16 is fixed, and the fluorine oil is stored in the oil storage portion 32. Lubricating oil L such as is stored.

A cylindrical permanent magnet 2 is attached to the support shaft 16.
The rotor 18, which is a rotating body with 0 disposed on the outer peripheral side, is supported while being engaged in a rotatably fitted manner, and the contact portion 18A protruding downward from the lower center of the rotor 18 has a boss 28. Abuts the top surface of. Therefore, a bearing portion is formed between the support shaft 16 and the rotor 18. Further, a plurality of, for example, 10 magnetic poles are formed on the permanent magnet 20 at equal intervals along the circumferential direction. That is, five N poles and S poles are formed adjacent to each other, and a total of 10 magnetic poles are formed.

On the other hand, at the bottom of the case body 12 near the outer peripheral side of the rotor 18, there is provided a stator base 22 shown in FIGS. 1 and 2 which is formed of a ferromagnetic material such as iron in an arc shape. The rotor 18 is fixed at one end side thereof. In addition, the pair of magnetic yokes 24 and 26 are attached to the bobbin 4.
By passing through each of the 0 through holes 40A, the coils 34 and 36, which are exciting coils wound around the bobbin 40, are attached and fixed to the pair of magnetic yokes 24 and 26, respectively.

As shown in FIG. 2, the pair of magnetic yokes 24 and 26 are formed so that their longitudinal directions extend in the direction orthogonal to the axial direction of the rotor 18.
The pair of magnetic yokes 24 are fixed to the stator base 22 so that a magnetic path can be formed in the stator base 22.
26 will be installed. Here, the angle α around the center of the rotor 18 between the pair of magnetic yokes 24 and 26 is, for example, 126 degrees.

On the other hand, the projecting portions on the inner peripheral side of the stator base 22, which project in the direction orthogonal to the axial direction of the rotor 18, are bent upwards perpendicularly to the surface of the stator base 22, A pair of stator magnetic pole portions 22A and 22B are provided on the inner peripheral side portion of the stator base 22.

That is, the pair of stator magnetic pole portions 22
A and 22B are integrally formed with the stator base 22, and have a structure separate from the magnetic yokes 24 and 26. The angle β1 between the magnetic yoke 24 and the stator magnetic pole portion 22A around the center of the rotor 18 is, for example, 45 °.
The stator magnetic pole portion 22A is arranged so as to have an angle of. In addition, the stator magnetic pole portion 22 is set so that the angle β2 between the magnetic yoke 26 and the stator magnetic pole portion 22B around the center of the rotor 18 is, for example, 45 °.
B is arranged. As a result, the angle γ between the pair of stator magnetic pole portions 22A and 22B around the center of the rotor 18 is also 126 °.

From the above, the pair of magnetic yokes 24, 26 and the pair of stator magnetic pole portions 22A, 22B are arranged in the rotor 18
It will be arranged radially around the center of. further,
The pair of coils 34 and 36 are connected to a control circuit (not shown), and the control circuit sends a drive pulse current having a predetermined phase difference at a predetermined frequency.

The pair of coils 34 and 36 excite the pair of magnetic yokes 24 and 26, respectively, by the drive pulse, so that the stator magnetic pole portion 22A and the magnetic yoke 2 are excited.
4 forms a magnetic path, and the stator magnetic pole portion 22B and the magnetic yoke 26 form a magnetic path. As a result, the pair of magnetic yokes 24 and 26 and the pair of stator magnetic pole portions 22.
As A and 22B are sequentially magnetized, the rotor 18 rotates by the number of pulses.

On the other hand, as shown in FIGS. 1 and 3, a driving gear 50 is formed at the upper end of the rotor 18 by being integrally formed with the rotor 18. Further, the output shaft 48 press-fitted into the output gear 54 is rotatably supported by the recess 44A of the boss 44 formed in the case body 12. An intermediate gear 52 including a large gear 52A and a small gear 52B is engaged with the support shaft 46 so as to be rotatably fitted thereto, and the boss 42 formed on the case body 12.
The support shaft 46 is attached to the recess 42A.

As described above, the intermediate gear 52 is rotatably arranged between the driving gear 50 and the output gear 54. The driving gear 50 and the intermediate gear 52 are the intermediate gear 5
The second large gear 52A meshes with the output gear 54 and the intermediate gear 52 meshes with the small gear 52B of the intermediate gear 52 to reduce the rotation of the rotor 18.

Next, the assembly of the stepping motor 10 according to this embodiment will be described. The stator base 22 is manufactured in advance by pressing or the like, and the lid member 14 and the case body 12 are
The bobbin 40 is manufactured by injection molding or the like.
In addition, the rotor 1 is placed in the permanent magnet 20 formed in advance.
By forming the resin material portion 8 by injection molding or the like, the permanent magnet 20 is attached to the outer peripheral side of the rotor 18. Further, the permanent magnet 20 is magnetized so as to have a plurality of magnetic poles at equal intervals along the circumferential direction. The stator magnetic pole portions 22A and 22B are bent when the stator base 22 is pressed.

Thereafter, the magnetic yokes 24 and 26 are fixed to the stator base 22 at predetermined positions by welding or the like, and the coil 3
The magnetic yokes 24 and 26 are passed through the through hole 40A of the bobbin 40 around which the coils 4 and 36 are wound, and the stator base 22 is attached to the bottom of the case body 12. This causes the magnetic yokes 24 and 26 to move to the coils 34 and 36, respectively.
With the coils 34, 36 passing through the stator base 2
It will be attached to 2.

Further, the metal support shaft 16 is provided with a recess 28A of a boss 28 formed in the case body 12 from above in FIG.
By press-fitting the support shaft 46 into the recess 42 </ b> A of the boss 42 formed in the case body 12, one end sides of the support shafts 16 and 46 are respectively supported by the case body 12. By engaging the rotor 18 with the support shaft 16 in this state, the rotor 18 is rotatably mounted in the case body 12 so that the annular wall portion 30 enters the concave portion shown in FIG. To be

Further, the output shaft 48 press-fitted into the output gear 54 is provided with the recess 44 of the boss 44 formed in the case body 12.
After being rotatably attached to A, an intermediate gear 52 for reducing the rotation of the rotor 18 is rotatably engaged with the support shaft 46. Along with this, the intermediate gear 52 is engaged with the driving gear 50 and the output gear 54 that are integrally formed when the rotor 18 is injection-molded.

Finally, as described above, the lid member 14 is attached to the upper surface of the case main body 12 while being fitted with the convex portion (not shown) formed on the case main body 12 in which the parts are contained, and fixed by screws or the like. The stepping motor 10 is completed. At the time of this assembly, the lubricating oil L is injected not only in the oil reservoir 32 but also in the bearing portion of each shaft.

Next, the operation of the stepping motor 10 according to this embodiment will be described. According to this embodiment, the rotor 18 has a structure in which the permanent magnet 20 is arranged on the outer peripheral side and the driving gear 50 is arranged on the upper end portion. Further, the support shaft 16 is attached to the boss 28 provided on the case body 12.
The lower end side which is one end side of the rotor 18 is fixed, and the rotor 18 is rotatably engaged with the support shaft 16, while the contact portion 18A that is one end of the rotor 18 is supported by the boss 28. An annular wall portion 30 for storing the lubricating oil L is arranged on the outer peripheral portion of the boss 28 to which the support shaft 16 is fixed.

Therefore, the annular wall portion 30 is arranged around the support shaft 16 fixed to the boss 28 of the case body 12, and the oil storage portion 32 in the wall portion 30 is lubricated with oil. Since L is stored, even when a low-viscosity lubricating oil L is selected to ensure operation at a low temperature, for example, from a low temperature of −40 ° C. to a high temperature of + 105 ° C., for example,
The lubricating oil L is securely stopped in the oil storage portion 32 by the wall portion 30, and the lubricating oil L is caused by the surface tension to cause the case body 1 to move.
The surface of No. 2 gets wet and does not spread. As a result, the amount of oil in the bearing portion of the rotor 18 does not decrease, so that the rotation noise of the rotor 18 does not increase, and smooth rotation of the rotor 18 is not hindered.

As described above, the stepping motor 10 according to the present embodiment has the gear train for deceleration and the permanent magnet 20.
However, according to the present embodiment, the lubricating oil L can be permanently secured and the rotation noise of the rotor 18 can be reduced for a long period of time. At the same time, a smooth rotation operation can be ensured for a long period of time.

On the other hand, the stepping motor 10 according to the present embodiment will rotate as follows. First, the pair of coils 34 and 36 attached to the pair of magnetic yokes 24 and 26 respectively excite the pair of magnetic yokes 24 and 26 as driving pulses having a phase difference are applied from the control circuit. To do. A pair of stator magnetic pole portions 22A and 22B, which are formed integrally with the stator base 22 and are separate from the magnetic yokes 24 and 26, form a magnetic path with the magnetic yokes 24 and 26. It is magnetized while forming.

As a result of this, for example, the coils 34, 36
When a drive pulse current having a phase difference is sent to the magnetic pole, a magnetic path is formed through the magnetic yoke 24 to the stator magnetic pole portion 22A via the stator base 22, and these magnetic poles become the S pole or the N pole. Magnetic yoke 2 with a phase difference
6 through the stator base 22 and the stator magnetic pole portion 22.
A magnetic path is formed up to B, and these become the S pole or the N pole.

As described above, the magnetic paths and the magnetic poles of the permanent magnets 20 of the rotor 18 cooperate to cause the rotor 18 to perform a stepping operation so as to rotate sequentially, and the stepping operation causes the rotor 18 to be integrally formed with the rotor 18. Driven gear 50
Is rotated, and this rotation is transmitted to the output gear 54 while being decelerated by the intermediate gear 52 to rotate the output shaft 48 and output to the outside of the stepping motor 10. That is, according to the present embodiment, the rotor 18 operates smoothly. Therefore, if the stepping motor 10 according to the present embodiment is adopted as a meter, the needle moved by the stepping motor 10 operates smoothly. Like

Next, a second embodiment of the motor according to the present invention will be described with reference to FIG. The same members as those described in the first embodiment are designated by the same reference numerals, and the duplicate description will be omitted. Although this embodiment has a structure similar to that of the first embodiment, as shown in FIG. 5, the inner peripheral surface of the distal end portion of the annular wall portion 30 that constitutes this embodiment is A lubricating oil outflow prevention piece 60 that projects toward the side is provided over the entire circumference.

Therefore, by forming the lubricating oil outflow prevention piece 60 protruding toward the inner peripheral side over the entire circumference at the tip portion of the annular wall portion 30, the same operational effect as that of the first embodiment is obtained. In addition to the above, the lubricating oil L can be more reliably prevented from leaking from the inside of the wall portion 30, and the lubricating oil L can be held in the bearing portion of the rotor 18 more reliably. The lubricating oil outflow prevention piece 60 may be formed by attaching another ring-shaped member to the tip portion of the wall portion 30 by adhering it, and is formed integrally with the wall portion 30 by the same member as the wall portion 30. You may.

Next, the test results comparing the loudness of the rotating noise of the stepping motor with and without the lubricating oil will be described. As shown in FIG. 6, the meter needle 72 is attached to the stepping motor 10 connected to the motor tester 70, and the stepping motor 10 is arranged in the soundproof room 78. Then, in this state, the microphone 76 connected to the level meter 74 is arranged so as to face the stepping motor 10, and the stepping motor 10 is placed in the soundproof room 78.
The noise level of was measured. Further, the sample 1 is obtained by lubricating the oil storage portion 32 with the lubricating oil L in the structure of the stepping motor 10 according to the first embodiment, and the lubricating oil L is lubricated in the oil storage portion 32 with the structure of the stepping motor 10 as well. The measurement was carried out using the sample 2 that was not used as the sample.

[0037]

[Table 1]

From Table 1, the rotation speed of the needle 72 is 100
In both cases of degrees / second and 300 degrees / second, the noise level of sample 1 in which lubricating oil L is lubricated is lower than the noise level of sample 2 in which lubricating oil L is not lubricated. It was confirmed that the noise level of Sample 1 was not more than 40 dB which is generally required in all cases.
As described above, if the lubricating oil L is securely held in the oil reservoir 32 as in the above-described embodiment, the lubricating oil L spreads in the bearing portion of the rotor 18 and the rotation noise of the rotor 18 is used. It can be seen that it has been reduced to the extent possible.

In the above embodiment, the present invention has been described by using the support shaft 16 supporting the rotor 18, but the present invention can be applied to other support shafts. Further, although the annular wall portion is formed into an annular shape in the above embodiment, the wall portion may not be an annular shape and may be a polygonal shape such as a quadrangular shape.

[0040]

According to the motor of the present invention, it is possible to permanently secure the lubricating oil, reduce the rotation noise for a long period of time, and secure the smooth operation.

[Brief description of drawings]

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

FIG. 2 is a plan view of the stepping motor according to the first embodiment of the present invention with a lid member and gears removed.

FIG. 3 is a sectional view of the stepping motor according to the first embodiment of the present invention.

FIG. 4 is an enlarged cross-sectional view around a rotor of the stepping motor according to the first embodiment of the present invention.

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

FIG. 6 is an explanatory diagram of a test method when measuring a noise level of a stepping motor.

FIG. 7 is a sectional view of a conventional stepping motor.

FIG. 8 is a plan sectional view of a stepping motor according to a conventional technique.

[Explanation of symbols]

10 Stepping motor 12 Case body (case) 16 Support shaft 18 Rotor (rotating body) 20 permanent magnets 28 Boss (shaft mounting part) 30 walls 50 driving gear 60 Lubricant oil outflow prevention piece

Continued front page    F term (reference) 5H605 BB05 BB10 BB14 CC04 DD09                       EB06 EB12 EB28 GG16                 5H607 AA12 BB01 BB07 BB10 BB14                       BB25 CC01 DD05 DD14 EE31                       GG01 GG09 GG12 GG28 JJ06

Claims (3)

[Claims] 1. A housing provided with a shaft mounting portion, a support shaft having one end fixed to the shaft mounting portion of the housing, and a shaft mounting portion of the housing rotatably engaged with the support shaft. A motor including: a rotating body having one end supported; and an annular wall portion arranged on an outer peripheral portion of the shaft mounting portion to collect lubricating oil. 2. The motor according to claim 1, wherein the rotating body is a rotor in which a permanent magnet is arranged on an outer peripheral side and a gear is arranged at an end portion. 3. The motor according to claim 1, wherein a lubricating oil outflow prevention piece formed so as to project toward the inner peripheral side is provided at the tip portion of the annular wall portion.