JP2003143797A - Motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor wherein a bearing housing and a motor case are assembled together to structurally prevent plays and the effect of cooling the inside of the motor. SOLUTION: Auxiliary projections 8 are formed between adjoining whirl-stop projections 7 of at least one bearing housing 2. Auxiliary notches 9 in which the auxiliary projections 8 are fitted are formed in the end face of the cylindrical motor case 1. Notches and the auxiliary notches 9 are extended in the direction of the thrust of a rotating shaft 4, to form cooling openings 10 for letting cooling air into the motor case 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor having a structure in which a bearing stand, which supports a bearing that pivotally supports a rotary shaft of a rotor, is attached to both end faces of a cylindrical motor case.

[0002]

2. Description of the Related Art As shown in FIG. 5, conventionally, a bearing base 2 supporting a bearing 5 pivotally supporting a rotary shaft 4 of a rotor 3 is attached to both end faces of a cylindrical motor case 1. In the motor, notches 6 are provided at a plurality of positions on both cylinder end surfaces of the cylindrical motor case 1, and a plurality of anti-rotation projections 7 are provided on the outer peripheral surface of the bearing base 2 in the outer diameter direction. The rotation stopper projections 7 are fitted into the notches 6 to prevent rotation in the circumferential direction, and the bearing bases 2 are attached to both cylinder end surfaces of the motor case 1. Here, the anti-rotation projections 7 and the notches 6 are located at four positions on the outer peripheral surface of the bearing base 2 and the cylinder end surface of the motor case 1 at intervals of approximately 90 ° in the axial direction of the rotary shaft 4. Are provided in each. In addition, the bearing base 2 and the motor case 1 are attached by bending both cylinder end faces of the motor case 1 inward so that the outer peripheral surface of the respective bearing bases 2 other than the rotation stopping projections 7 is fixed to the rotary shaft 4. It is performed by crimping in the thrust direction. Reference numeral 20 in the drawing denotes a cooling air introduction hole for introducing cooling air into the motor case 1, and reference numeral 21 in the drawing denotes a magnet mounted on the inner surface of the motor case 1.

[0003]

By the way, although the above-mentioned motor is used for various purposes, for example, when it is used by being incorporated in an electric tool such as an electric drill, the motor drive is particularly transmitted. When a gearbox in which gears and the like are installed is fixed to a housing of an electric tool, and a bearing base 2a on the output side is fixed to the gearbox and a motor is installed in the housing, the power is rapidly turned on and off. Due to the operation, a load that causes the fixed bearing base 2a to rotate in the circumferential direction is exerted on the motor case 1, and therefore, the motor case 1 will change with time.
The bearing base 2 may cause rattling in the circumferential direction. For this reason, there have been problems that the driving loss of the motor increases and the power consumption increases, and that the life of the bearing 5 that pivotally supports the rotating shaft 4 is shortened. Further, there is a problem that the coil portion 12 of the rotor 3 generates heat when the motor is overloaded and the coil portion 12 is burned.

The present invention has been made in view of the above points, and a motor in which the bearing base and the motor case are mounted to prevent rattling and at the same time the cooling effect inside the motor is improved. The challenge is to provide.

[0005]

In order to solve the above problems, a motor according to claim 1 of the present invention has notches 6 at a plurality of positions on both end faces of a cylindrical motor case 1 for housing a rotor 3. A plurality of anti-rotation protrusions 7 are provided on the outer peripheral surface of the bearing stand 2 that supports the bearing 5 that pivotally supports the rotation shaft 4 of the rotor 3, and the anti-rotation protrusions 7 are fitted into the notches 6, respectively. In the motor in which the bearing bases 2 are attached to both cylinder end surfaces of the motor case 1 so as to cover the respective cylinder end faces, the auxiliary protrusions 8 are provided between the adjacent detent protrusions 7 of at least one bearing base 2 and An auxiliary notch 9 for fitting the auxiliary protrusion 8 is provided on the cylinder end surface of the motor case 1, and the notch 6 and the auxiliary notch 9 are extended in the thrust direction of the rotating shaft 4 to cool the motor case 1 with cooling air. Shape cooling opening 10 for introducing Characterized in that it was. As a result, the auxiliary protrusion 8 is provided between the adjacent detent protrusions 7 of at least one bearing base 2 and the motor case 1
By providing the auxiliary notch 9 for fitting the above-mentioned auxiliary protrusion 8 on the cylindrical end surface of the, the mounting of the motor case 1 and the bearing base 2 is assisted in addition to the fitting of the whirl-stop protrusion 7 into the notch 6. The projection 8 is fitted into the auxiliary notch 9 so as to be strongly regulated in the circumferential direction, that is, the rattling of the bearing base 2 and the motor case 1 in the circumferential direction is further strongly prevented. It is a thing. At this time, the cylinder end surface of the motor case 1 is provided with a large number of notches such as the auxiliary notch 9 in addition to the notch 6, and these notches (notch 6 and auxiliary notch 9) are provided in the rotary shaft 4 Since the cooling opening 10 for introducing the cooling air is formed in the motor case 1 by extending in the thrust direction, the rattling of the bearing base 2 and the motor case 1 in the circumferential direction is prevented as described above. At the same time, a large amount of cooling air can be introduced into the motor case 1 from a large number of places by the cooling opening 10 and the cooling effect inside the motor can be improved.

A motor according to claim 2 is the motor according to claim 1.
In addition, at least one of the anti-rotation protrusion 7 and the auxiliary protrusion 8 is extended to the outside of the bearing stand 2 to form the heat dissipation portion 11. As a result, the heat generated in the rotor 3 reaches the bearing base 2 through the motor case 1, but at least one of the anti-rotation protrusion 7 and the auxiliary protrusion 8 provided on the bearing base 2 is located outside the bearing base 2. The heat dissipation part 11
That is, the heat dissipation portion 11 is positioned so as to face the cooling opening 10 of the notch 6 or the auxiliary notch 9, and the heat dissipation portion 11 is introduced into the motor case 1. Cooling opening 10 which is a passage for cooling air
The surface area of the bearing base 2 is increased so that the heat dissipation effect to the air of the bearing base 2 can be improved, and thus the cooling effect inside the motor can be further improved. .

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below based on the embodiments shown in the accompanying drawings.

1 and 2 show an example of an embodiment of the present invention. The motor of this example has a coil portion 12 on the periphery of the rotary shaft 4.
Is integrally provided to form the rotor 3, and the outer surface of the coil portion 12 is arranged along the inner surface of the magnet 21 arranged along the inner surface of the cylindrical motor case. The rotor 3 is housed inside a cylindrical motor case 1 so as to be positioned on the cylinder end surface, and the motor is mounted in the center of a bearing stand 2 mounted so as to cover both cylinder end surfaces of the motor case 1. A bearing accommodating portion 13 which is recessed outward from the inside of the case 1 is formed, and a bearing 5 pivotally supporting the rotating shaft 4 is accommodated in the bearing accommodating portion 13.
A rotary shaft through hole 14 is formed in the center of the bearing housing 13 so as to penetrate the inside and outside of the motor case 1, and both ends of the rotary shaft 4 are inserted into the rotary shaft through hole 14. . Here, in the bearing bases 2 attached to both cylinder end surfaces of the motor case 1, the end projection amount of the rotary shaft 4 of the rotor 3 protruding from the rotary shaft through hole 14 to the outside of the motor case 1 is increased and the rotor 3 is Bearing base 2 at the end of
Is a bearing base 2a on the output side, and the amount of protrusion of the end portion of the rotating shaft 4 of the rotor 3 protruding from the rotating shaft through hole 14 to the outside of the motor case 1 is reduced. In addition, the bearing stand 2 in which the brush 15 is interposed between the end of the rotor 3 and the bearing stand 2 is a bearing stand 2b on the input side.
Is. Reference numeral 16 in the figure denotes a commutator that is in contact with the brush 15 and supplies a current to the rotor 3.

The mounting portion between the motor case 1 and the bearing base 2 has the following structure. In the bearing base 2, anti-rotation protrusions 7 are provided outward at a plurality of locations on the outer peripheral surface thereof. And, in the output side bearing stand 2a,
In addition to the above-mentioned anti-rotation protrusion 7, an auxiliary protrusion 8 is provided outside between the adjacent anti-rotation protrusions 7. On the other hand, in the motor case 1, cutouts 6 into which the above-mentioned rotation-stopping projections 7 are fitted are provided at a plurality of positions on both end faces of the cylinder. On the cylinder end surface of the motor case 1 to which the output side bearing stand 2a is attached, in addition to the notch 6, an auxiliary notch 9 into which the auxiliary protrusion 8 is fitted is provided in the adjacent notch 6. It is provided in between. Also, the output side bearing stand 2a
The notch 6 and the auxiliary notch 9 provided on the cylinder end surface of the motor case 1 on which the motor is mounted are extended in the thrust direction of the rotary shaft 4 to introduce cooling air into the motor case 1. The part 10 is formed. In this example, the anti-rotation protrusions 7 and the notches 6 are arranged on the outer peripheral surface of the bearing base 2 and the cylindrical end surface of the motor case 1 at intervals of about 90 ° in the axial direction of the rotary shaft 4. The auxiliary protrusions 8 and the auxiliary cutouts 9 are provided at the respective positions, and the auxiliary protrusions 8 and the auxiliary cutouts 9 are provided on the outer peripheral surface of the bearing stand 2 and the cylinder end surface of the motor case 1 at the installation positions of the above-mentioned rotation stopper projections 7 and the cutouts 6. Are provided at four positions with an interval of about 45 ° in the circumferential direction of the rotary shaft 4. In addition, the motor case 1 is formed by thinning the wall thickness of the motor case 1 at a portion where both the notches 6 and the auxiliary notches 9 are not provided in the both end surfaces of the motor case 1 while leaving the flush outer surface of the motor case 1 as it is. A fin piece 17 is formed. The inner surface of the fin piece 17 forms a step portion 18 arranged so that the bearing base 2 is fitted therein.

The motor case 1 constructed as described above
The bearing stand 2 and the bearing stand 2 are attached as follows.
First, the bearing stand 2b on the input side and the motor case 1 are arranged in the step portion 18 of the motor case 1 by fitting the anti-rotation protrusion 7 into the notch 6. Further, the output side bearing stand 2a and the motor case 1 are fitted to the cutouts 6 of the rotation preventing projections 7 and the auxiliary projections 8 are fitted to the auxiliary cutouts 9 so that the step portion 18 of the motor case 1 is fitted. The bearing stand 2a is arranged in the. And the fin piece 1 of the motor case 1
The tip end portion of 7 is bent in the inner diameter direction, and the bearing base 2 arranged in the step portion 18 is caulked at the tip portion of the fin piece 17 in the thrust direction of the rotating shaft 4 to cover the cylinder end surface of the motor case 1. The bearing base 2 is attached in such a manner.

As described above, in the state where the input side bearing stand 2b and the motor case 1 are attached, the rotation preventing projection 7 is fitted into the notch 6 as in the prior art, so that the rotation shaft 4 is fixed. Although it is provided with a rotation stopper in the circumferential direction of the shaft, in the state where the output side bearing base 2a and the motor case 1 are attached, the notch 6 of the rotation stopper protrusion 7 in the prior art is provided. In addition to the fitting of the auxiliary projection 8 into the auxiliary notch 9, the rotation of the rotary shaft 4 in the circumferential direction of the rotary shaft 4 is prevented. That is, in the mounting structure of the output side bearing stand 2a and the motor case 1,
The auxiliary protrusion 8 is fitted into the auxiliary notch 9 and therefore is provided with a stronger detent as compared with the prior art.
As described in the section of the prior art, a gearbox in which gears for transmitting the motor drive are installed is fixed to the housing of the electric tool, and the bearing stand 2a on the output side is fixed to the gearbox so that the motor is installed in the housing. Is installed (the output side bearing base 2a is in a completely fixed state and the motor case 1 is in an imperfectly fixed state), it is fixed to the motor case 1 by the abrupt on / off operation of the power supply. A load such as rotating in the circumferential direction is significantly applied to the output side bearing stand 2a, but in the motor of the present example, as described above, between the output side bearing stand 2a and the motor case 1. Since a strong detent is applied to the motor, the durability performance of the motor against the above load can be improved. Therefore, in the motor of this example, the backlash between the output side bearing base 2a and the motor case 1 does not occur in the circumferential direction even with time, and the output side bearing base 2
It should be noted that problems such as an increase in power consumption due to an increase in drive loss of the motor caused by rattling in the circumferential direction between the motor case 1 and the motor case 1 and a decrease in the life of the bearing 5 pivotally supporting the rotating shaft 4 do not occur. It has become.

When the motor is in use, especially when the motor is used in an overloaded state, the coil portion 12 of the rotor 3 generates heat. If the heat of the coil portion 12 is not properly dissipated, the coil portion 12 will be burnt. Even in the conventional motor, however, in order to dissipate the heat of the coil portion 12, the output side bearing stand 2
A cooling air introduction hole 20 is provided at an appropriate position in a, and cooling air is introduced into the motor case 1 through the cooling air introduction hole 20. The cooling air introduced into the motor case 1 is the air outside the motor case 1, and the larger the air volume is, the more heat is dissipated from the coil portion 12, which is preferable. In the motor of this example, as shown by the arrow A, in addition to the cooling air introduction hole 20 of the prior art, the cooling opening 10 described above is used.
Also, since the cooling air can be introduced into the motor case 1, that is, the opening area communicating with the inside and outside of the motor case 1 is increased so that a large amount of cooling air can be introduced into the motor case 1. The cooling effect inside the motor is improved. The cooling air taken into the motor case 1 is a cooling air discharge hole 19 that is opened on the cylinder side surface of the motor case 1 before the brush 15 installation portion.
Is discharged to the outside of the motor case 1. In this example, a plurality of cooling air discharge holes 19 are provided side by side in the circumferential direction of the cylinder side surface of the motor case 1 in order to improve the efficiency of cooling air discharge.

The cooling opening 10 is formed by extending the notch 6 and the auxiliary notch 9 provided in the motor case 1 in the thrust direction of the rotary shaft 4 as described above. . That is, in order to improve the attachment strength between the motor case 1 and the bearing base 2, the cylinder end surface of the motor case 1 is provided with a plurality of notches 6 and auxiliary notches 9. Further, the cooling opening 10 is formed by utilizing the auxiliary notch 9 and extending the notch 6 and the auxiliary notch 9 in the thrust direction of the rotating shaft 4 so as to increase the opening area. The cooling opening 10 not only allows a large amount of cooling air to be introduced into the motor case 1 by the amount of the opening area of the cooling opening 10 as compared with the prior art, but also the cutout 6 and the auxiliary cutout. Since the plurality of notches 9 are arranged side by side in the circumferential direction of the cylinder end surface of the motor case 1, the cooling air is efficiently and substantially evenly distributed in the motor case 1 from the circumferential direction of the cylinder end surface of the motor case 1. It is possible to introduce it, that is, it is possible to introduce a large amount of cooling air into the motor case 1 efficiently. Since the cooling opening 10 is an opening formed on the side surface of the cylinder of the motor case 1, the bearing stand 2a on the output side is closely fixed to the gear box so that the cooling air introduction hole 20 is closed by the gear box. Even in the case of closing, the cooling opening 10 can be opened without any change, and there is an advantage that the cooling air can be introduced into the motor case 1.

3 and 4 show another embodiment of the present invention. This example is an example in which the anti-rotation protrusion 7 and the auxiliary protrusion 8 in the example of the previous embodiment are extended to the outside of the bearing base 2 to form the heat dissipation portion 11. As described in the example of the previous embodiment, when the motor is used, particularly when the motor is used in an overloaded state, heat is generated in the coil portion 12. In order to prevent the coil portion 12 from being burned by the heat, It is preferable that the heat is dissipated quickly. In the example of the previous embodiment, the large amount of cooling air is efficiently introduced into the motor case 1 to improve the heat radiation effect of the heat generated in the coil portion 12. However, in the present example, The heat generated in the coil portion 12 is further transferred by utilizing the heat transfer phenomenon (arrow B) that reaches the bearing stand 2 by heat conduction through the magnet 21 and the motor case 1 or heat transfer through the atmosphere inside the motor case 1. The heat radiation effect of the heat generated in the coil portion 12 is improved.

Specifically, the bearing stand 2 and the motor case 1
Is formed of a material having a high thermal conductivity such as metal, and the anti-rotation projection 7 and the auxiliary projection 8 provided on the bearing base 2 are formed on the bearing base 2.
The heat radiating portion 11 is formed by extending outward. According to this, the heat generated in the rotor 3 (coil portion 12) reaches the bearing base 2 through the motor case 1 and the like, but the heat dissipation portion 11 increases the surface area of the bearing base 2 in contact with the air around the motor. The heat dissipation effect of the heat transferred to the bearing stand 2 is improved. Here, particularly in the bearing stand 2a on the output side, the whirl-stop projection 7 and the auxiliary projection 8 that form the heat dissipation portion 11 are fitted into the notch 6 and the auxiliary notch 9 that form the cooling opening 10, respectively. Because
The heat radiating portion 11 of the output side bearing base 2a is arranged so as to face the cooling opening 10 which is a portion where the cooling air is introduced into the motor case 1, that is, the output side bearing base 2a.
Since the heat radiating portion 11 of a has an increased surface area in contact with the cooling air of the output side bearing base 2a, the output side bearing base 2a
The heat dissipation effect of the heat transferred to the is significantly improved. As described above, in the motor of this example, the cooling air introduction hole 20
In addition to introducing cooling air from the cooling opening 10 into the motor case 1 to air-cool the coil portion 12, the bearing stand on the output side so as to face the cooling opening 10 which is the passage of the cooling air. The surface area of 2a is increased by the heat radiating section 11 to radiate the heat conducted from the coil section 12 to the output side bearing stand 2a, and the cooling of the inside of the motor is possible even compared to the example of the previous embodiment. The effect is further improved.

In this example, the heat dissipation portion 11 is formed on both the rotation stop projection 7 and the auxiliary projection 8, but the heat dissipation portion 1 is formed on at least one of the rotation prevention projection 7 and the auxiliary projection 8.
Forming No. 1 can obtain the effect of the present example described above to some extent.

[0017]

As described above, in the invention according to claim 1 of the present invention, notches are provided at a plurality of positions on both cylinder end surfaces of a cylindrical motor case for accommodating a rotor, and a rotary shaft of the rotor is provided. A plurality of anti-rotation protrusions are provided on the outer peripheral surface of the bearing base that supports the pivotally supported bearing, and the anti-rotation protrusions are fitted into the notches to attach the bearing base to both cylinder end faces of the motor case. In the motor mounted as described above, auxiliary protrusions are provided between adjacent detent protrusions of at least one bearing stand, and auxiliary cutouts for fitting the auxiliary protrusions are provided on the cylinder end surface of the motor case. The notch and the auxiliary notch are extended in the thrust direction of the rotary shaft to form a cooling opening for introducing cooling air into the motor case. Lack In addition to the fitting of the auxiliary projections to the auxiliary notches, it is performed with a stronger regulation in the circumferential direction, that is, the backlash between the bearing stand and the motor case in the circumferential direction is strong. It will be prevented.
At this time, many cutouts such as auxiliary cutouts are made in addition to the cutouts on the cylinder end surface of the motor case. These cutouts (cutouts and auxiliary cutouts) are extended in the thrust direction of the rotary shaft. By forming the cooling opening for introducing the cooling air into the motor case, the play of the bearing stand and the motor case in the circumferential direction can be prevented as described above, and at the same time, the cooling opening allows the motor to move. A large amount of cooling air can be introduced into the case from a large number of places, and the cooling effect inside the motor can be improved.

In addition to the effect of claim 1, in the invention of claim 2, at least one of the anti-rotation projection and the auxiliary projection is extended to the outside of the bearing stand to form a heat dissipation portion. As a result, the heat generated in the rotor reaches the bearing base through the motor case, but the surface area of the bearing base is set so that the heat radiation part faces the cooling opening, which is the passage for the cooling air introduced into the motor case. Since the effect of radiating heat to the air from the bearing stand can be improved, the effect of cooling the inside of the motor can be further improved.

[Brief description of drawings]

FIG. 1 is a partial perspective view of a motor according to an example of an embodiment of the present invention.

2A and 2B show a motor of the above, where FIG. 2A is a left front view, FIG. 2B is a side sectional view, FIG. 2C is a right front view, and FIG. It is a partial side view which shows the fitting to an auxiliary notch, (e) is a partial side view which shows the fitting of a rotation stop protrusion to the notch, and (f) is a partial side view which shows a cooling air discharge hole. Is.

FIG. 3 is a partial perspective view of a motor according to another example of the embodiment of the present invention.

[Fig. 4] Fig. 4 is a view showing a motor of the same, in which (a) is a left front view, (b) is a side sectional view, and (c) is a right front view.

FIG. 5 shows a prior art example motor,
(A) is a left front view, (b) is a side sectional view,
(C) is a right front view.

[Explanation of symbols]

1 motor case 2 bearing stand 3 rotor 4 rotation axes 5 bearings 6 notches 7 Anti-rotation protrusion 8 auxiliary protrusions 9 auxiliary notches 10 Cooling opening 11 Heat sink

Claims (2)

[Claims] 1. A plurality of whirl-stops are provided on an outer peripheral surface of a bearing base that supports a bearing that pivotally supports a rotation shaft of a rotor, by providing notches at a plurality of positions on both end surfaces of a cylindrical motor case that houses a rotor. In a motor in which projections are provided in a protruding manner, and the above-mentioned detents are fitted in the notches, the bearing bases are attached so as to cover the end faces of both cylinders of the motor case, respectively. An auxiliary protrusion is provided between the stopper protrusions, an auxiliary notch for fitting the auxiliary protrusion is provided on the cylinder end surface of the motor case, and the notch and the auxiliary notch extend in the thrust direction of the rotary shaft. A motor characterized in that a cooling opening for introducing cooling air is formed in the motor case. 2. The motor according to claim 1, wherein at least one of the anti-rotation protrusion and the auxiliary protrusion is extended to the outside of the bearing stand to form a heat radiating portion.