JP6822716B1 - Bearing fixing structure in outer rotor type rotary electric machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an improved outer rotor type rotary electric machine bearing fixing structure. SOLUTION: A housing is composed of an inner housing 40 and an outer housing 50, both of which have an outer surface and an inner side surface, and has a cylindrical shape having a square cross section, and a first portion at the center of each side of both ends of the inner housing 40. 1 An arc-shaped first bearing body mounting groove 41 corresponding to the outer diameter and width of the first bearing body 21 of the flanged bearing 20 is provided in the central portion of each side of both ends of the outer housing 50. An arc-shaped first flange portion mounting groove 51 corresponding to the outer diameter of the first flange portion 22 of the flanged bearing 20 is formed, and the first bearing body 21 is formed in the first bearing body mounting groove 41 of the inner housing 40. It is mounted by press fitting, and the first flange portion 22 is mounted on the first flange portion mounting groove 51 of the outer housing 50. [Selection diagram] Fig. 1

Description

The present invention relates to an improvement in a bearing fixing structure in an outer rotor type rotary electric machine in which a rotor is arranged on the outside of the stator and the shaft and the rotor are rotated via the bearing.

For example, as a countermeasure against the labor shortage that is becoming more serious in the fields of logistics and agriculture, the range of utilization of drones, which are unmanned aerial vehicles equipped with multiple rotors and capable of flying wirelessly using radio waves, is expanding. In drones, from the viewpoint of the need to transport heavy objects to long distances such as depopulated areas and remote islands, it is desired to popularize motors that are larger than the small motors that have been used conventionally.

In this drone, a rotating electric machine (motor) that works as an electric machine occupies an important position as a power source. An outer rotor type rotary electric machine is generally used for the rotary blade of the drone.

The outer rotor type rotary electric machine is a rotary electric machine in which a rotor is arranged outside the stator to rotate the shaft, and a bearing is arranged at the rotating portion of the shaft. For example, Patent Document 1 discloses the following structure with respect to the fixed structure of the bearing.

As shown in FIG. 5, a hollow housing 110 is fixed to the front cover 100, and a stator core 130 constituting the stator 120 is attached to the outer periphery of the housing 110. A coil 150 wound around the bobbin 140 is attached to the stator core 130.

Further, the housing 110 is formed with a through hole 111 penetrating the central portion and a wide hole portion 113 at the upper and lower ends having a diameter longer than that of the through hole 111 and whose side surface portion is a bearing mounting surface 112. .. The pair of bearings 200 and 300 are inserted into the wide hole portion 113 and fixed to the bearing mounting surface 112. The rotor shaft 600 is rotatably supported via a pair of bearings 200 and 300. The rotor 160 includes a cup-shaped rotor case 170 in which the base end of the rotor shaft 600 is press-fitted to the bottom surface, and a cylindrical permanent magnet 180 fixed to the inside of the cylindrical wall surface of the rotor case 170. .. The pair of bearings 200 and 300 used in Patent Document 1 are general bearings without flanges.

On the other hand, Patent Document 2 discloses a technique using a flanged bearing. As shown in FIG. 6, 210 is a flanged bearing. Reference numeral 220 denotes a labyrinth seal formed by a gap between the flange flat portion 211 of the bearing 210 and the opposing labyrinth flat portion 221. In the bearing 210, the bearing main body 212 is inserted into the groove 231 of the housing 230, and the inner ring portion of the bearing 210 is pressed by the height setting protrusion 241 of the spindle hub 240, so that the flange portion is attached to the end portion of the housing 230. The bearing body 212 side of 213 is in contact and fixed to the housing 230.

JP-A-2007-288939 Japanese Unexamined Patent Publication No. 4-317546

By the way, the method of mounting the bearing on the housing is performed by press-fitting to the bearing mounting surface and / and tightening the end surface of the raceway ring with nuts and bolts. However, in the case of press-fitting, the bearing is a precision part, so it has a substantially cylindrical shape. When processing a thick metal housing, it is necessary to keep the dimensional accuracy, shape accuracy, roughness, etc. of the bearing mounting portion within the allowable tolerances, which increases the cost.

On the other hand, in the case of tightening the end face of the raceway ring with nuts and bolts, the structure becomes complicated, and the cost increases and the weight increases at the same time.

Therefore, the present invention solves the above-mentioned problems and improves the fixing structure of the bearing. Therefore, in the present invention of claim 1, the rotor is arranged on the outside of the stator, and the shaft and rotation are provided via the bearing. It is a fixed structure of the bearing in the outer rotor type rotary electric machine that rotates the child, the bearing is a bearing with a flange, and the housing accommodating the bearing with a flange is an inner housing in which the shaft is arranged inside and an inner housing. The inner housing and the outer housing both have an outer surface and an inner side surface, and the cross section is a tubular shape having a square outer surface and an inner side surface, and the outer housing is a shaft. In the insertion direction of, at both ends of the inner housing, at the center of each side with a square cross section, an arc-shaped bearing body corresponding to the outer diameter and width of the bearing body of the flanged bearing A mounting groove is formed, and at both ends of the outer housing, an arc-shaped flange mounting groove corresponding to the outer diameter of the flange of the bearing with a flange is formed at the center of each side having a square cross section. The bearing body of the bearing with a flange is attached by press fitting to the bearing body mounting groove of the inner housing so that the bearing body faces each other, and the flange of the flanged bearing is attached to the flange mounting groove of the outer housing. It is a fixed structure of bearings in an outer rotor type rotary electric machine, which is characterized by being able to be mounted.

In the present invention of claim 1, the bearing is a flanged bearing, and the housing accommodating the flanged bearing is composed of an inner housing in which the shaft is arranged inside and an outer housing arranged outside the inner housing. The inner and outer housings are both tubular with outer and inner surfaces and square in cross section on both the outer and inner surfaces, and the outer housing is longer and inner than the inner housing in the shaft insertion direction. At both ends of the housing, arc-shaped bearing body mounting grooves corresponding to the outer diameter and width of the bearing body of the flanged bearing are formed at the center of each side with a square cross section, and both ends of the outer housing. In the central portion of each side having a square cross section, an arc-shaped flange mounting groove corresponding to the outer diameter of the flange of the flanged bearing is formed, so that the inner housing for mounting the flanged bearing and the inner housing for mounting the flanged bearing are formed. It is possible to reduce the number of arc-shaped processed portions with respect to the outer housing.

The inner housing and the outer housing both have a square cross section and are not cylindrical, but in the outer rotor type rotary electric machine, the inner housing and the outer housing are both fixed and do not rotate, so that the performance of the rotary electric machine There is no effect on.

Further, since the bearing body portion of the flanged bearing is press-fitted into the bearing body portion mounting groove portion of the inner housing, the flanged bearing can be reliably mounted on the inner housing.

Further, the outer housing is longer than the inner housing in the shaft insertion direction, and the flanged bearing is press-fitted into the bearing body mounting groove of the inner housing so that the flange body faces the bearing body. Since the flange portion of the flanged bearing is attached to the flange portion mounting groove portion of the outer housing, the flanged bearing can be fixed by sandwiching the inner housing and the outer housing from both ends.

According to a second aspect of the present invention, in the first aspect of the present invention, the inner housing and the outer housing are aluminum bearing fixing structures in an outer rotor type rotary electric machine.

In the present invention of claim 2, since the inner housing and the outer housing are made of aluminum, the weight of the inner housing and the outer housing can be reduced.

Further, since aluminum is a soft metal, it is easy to process, and in the inner housing, when the bearing body is press-fitted, the bearing body mounting groove can be expanded outward, and the bearing body to the bearing body can be expanded. The pressure from the side surface of the mounting groove can be relaxed.

In the invention of claim 2, the thickness of the closest portion between the outer surface of the inner housing and the bearing body mounting groove in the cross section of the inner housing is 0.001 mm or more, 0. . This is a fixed structure of bearings in an outer rotor type rotary electric machine of 500 mm or less.

In the present invention of claim 3, in the cross section of the inner housing, the thickness of the closest portion between the outer surface of the inner housing and the bearing body mounting groove is 0.001 mm or more and 0.500 mm or less. When the bearing body is press-fitted, the effect of expanding the side surface of the bearing body mounting groove to the outside becomes remarkable, and the pressure from the side surface of the bearing body mounting groove on the bearing body can be relaxed. The thickness of the closest portion between the outer surface of the inner housing and the bearing body mounting groove is more preferably 0.001 mm or more and 0.100 mm or less, and further preferably 0.001 mm or more and 0.050 mm or less. ..

The bearing is a flanged bearing, and the housing accommodating the flanged bearing is composed of an inner housing in which the shaft is arranged inside and an outer housing in which the shaft is arranged outside the inner housing. Both have an outer surface and an inner side surface, and the cross section is a square shape on both the outer surface and the inner side surface. The outer housing is longer than the inner housing in the insertion direction of the shaft, and the cross section is formed at both ends of the inner housing. An arc-shaped bearing body mounting groove corresponding to the outer diameter and width of the bearing body of the flanged bearing is formed in the center of each side of the square, and each side of the square cross section is formed at both ends of the outer housing. Since an arc-shaped flange mounting groove corresponding to the outer diameter of the flange of the flanged bearing is formed in the central portion of the above, an arc-shaped processed portion for the inner housing and the outer housing for mounting the flanged bearing is formed. Can be reduced.

Further, since the bearing body portion of the flanged bearing is press-fitted into the bearing body portion mounting groove portion of the inner housing, the flanged bearing can be reliably mounted on the inner housing.

Further, the outer housing is longer than the inner housing in the shaft insertion direction, and the flanged bearing is press-fitted into the bearing body mounting groove of the inner housing so that the flange body faces the bearing body. Since the flange portion of the flanged bearing is attached to the flange portion mounting groove portion of the outer housing, the flanged bearing can be fixed by sandwiching the inner housing and the outer housing from both ends.

It is a vertical sectional view explaining the fixing structure of the bearing which concerns on embodiment of this invention. It is sectional drawing of the bearing with flange which concerns on embodiment of this invention. (A) is a top view and (b) is a sectional view taken along the line AA in (a) of the inner housing according to the embodiment of the present invention. (A) is a top view and (b) is a sectional view taken along the line BB in (a) of the outer housing according to the embodiment of the present invention. It is a vertical cross-sectional view explaining the fixed structure of a conventional bearing (Patent Document 1). It is a vertical cross-sectional view explaining the fixed structure of a conventional bearing, and (b) is an enlarged view of the alternate long and short dash line portion in (a) (Patent Document 2).

Hereinafter, the bearing fixing structure according to the present invention will be described with reference to FIGS. 1 to 4. The types of flanged bearings, shafts, inner housing, outer housing dimensions, etc. described below are examples, and may be appropriately changed depending on the specifications of the rotary electric machine, the specifications of the flanged bearings used, and the like.

FIG. 2 is a cross-sectional view of the flanged bearing 10 according to the present embodiment. As shown in FIG. 1, in the present embodiment, in consideration of the ease of inserting the shaft 60 into the flanged bearing 10, the first flanged bearing 20 and the second flanged bearing 30 having different inner diameters d are used. .. In addition, you may use only two of only one of them.

Further, from the relationship between the inner housing 40 and the outer housing 50, which will be described in detail later, the bearing 20 with the first flange and the bearing 30 with the second flange to be used have the outer diameter D and the flange portion 12 of the bearing body 11 of FIG. It is desirable to use the same outer diameter D1.

In the present embodiment, the first flanged bearing 20 is a flanged bearing DDLF-1910ZZ (inner diameter d = 10 mm) manufactured by MinebeaMitsumi Co., Ltd., and the second flanged bearing 30 is a DDRF-1980 (inner diameter d) manufactured by the same company. = 8 mm) was used. In the above two types of flanged bearings, the outer diameter D of the bearing body 11 in FIG. 2 is 19 mm, and the outer diameter D1 of the flange portion 12 is 22 mm, which are the same dimensions.

3A and 3B are views for explaining the inner housing 40, where FIG. 3A is a top view and FIG. 3B is a sectional view taken along the line AA in FIG. The inner housing 40 is a tubular square timber having a square cross section. The material is aluminum, and in (a), the width W1 of the outer surface is 19 mm and the wall thickness t1 is 2 mm.

As shown in FIGS. 1, 2 and 3 (b), both ends of the inner housing 40 have a depth corresponding to the width (B in FIG. 2) of the first bearing body 21 of the first flanged bearing 20. Depth (h2 = 4.5 mm) corresponding to the width (B in FIG. 2) of the first bearing main body mounting groove 41 and the second bearing main body 31 of the second flanged bearing 30 (h1 = 5.5 mm). ), The second bearing main body mounting groove 42 is formed. The length L1 of the inner housing 40 is 36 mm.

The diameter φ1 of the first bearing main body mounting groove 41 in FIG. 3A considers mounting by press fitting with respect to the outer diameter D of the bearing main body 11 (FIG. 2) (with respect to the outer diameter D of the bearing main body 11). Therefore, the diameter φ1 of the first bearing main body mounting groove 41 was designed to be slightly smaller) to be 18.998 mm. This also applies to the second bearing main body mounting groove 42. Therefore, the thickness of the closest portion between the first bearing main body mounting groove 41 and the second bearing main body mounting groove 42 and the outer surface of the inner housing 40 is 0.001 mm. The degree to which the diameter φ1 of the first bearing main body mounting groove 41 is designed to be smaller than the outer diameter D of the bearing main body 11 differs depending on the size of the bearing to be used and the like.

As is clear from FIG. 3, the processed portion of the inner housing 40 when forming the first bearing main body mounting groove 41 and the second bearing main body mounting groove 42 is compared with the case where the cylindrical housing is machined. Few. Needless to say, the processing accuracy can be the same as that for processing a cylindrical housing.

As shown in FIGS. 3A and 3B, an arcuate cutting hole 43 is formed inside the first bearing main body mounting groove 41 and the second bearing main body mounting groove 42 of the inner housing 40. There is. This is so that only the outer ring portion 13 of the bearing main body portion 11 in FIG. 2 is placed in the first bearing main body portion mounting groove portion 41 and the second bearing main body portion mounting groove portion 42. In the present embodiment, the diameter φ2 of the cutting hole 43 is set to 17.5 mm in accordance with the bearing 20 with the first flange.

When the wall thickness t1 of the inner housing 40 is thin and the width of the inner side surface is larger than the outer ring shoulder diameter Lo (FIG. 2) of the bearing main body 11, the cutting hole 43 is unnecessary. Further, the cutting hole 43 may be formed in accordance with the outer ring shoulder diameter Lo of the first flanged bearing 20 and the second flanged bearing 30, respectively. In this case, the diameter φ2 of the cutting hole 43 on the side of the bearing 30 with the second flange is 16.3 mm.

4A and 4B are views for explaining the outer housing 50, where FIG. 4A is a top view and FIG. 4B is a sectional view taken along line BB in FIG. 4A. Like the inner housing 40, the outer housing 50 is a tubular square timber having a square cross section, and the material is aluminum. In (a), the width W2 of the outer surface is 24 mm and the wall thickness t2 is 2 mm. ..

As shown in FIG. 4B, both ends of the inner housing 40 have a depth (h3 = 1.5 mm) corresponding to the width (C1 in FIG. 2) of the first flange portion 22 of the first flanged bearing 20. The second flange portion mounting groove portion 52 having a depth h4 corresponding to the width of the first flange portion mounting groove portion 51 and the second flange portion 32 of the second flanged bearing 30 is formed.

In the present embodiment, the widths of the first flange portion 22 and the second flange portion 32 (C1 in FIG. 2) of the first flanged bearing 20 and the second flanged bearing 30 are the same, so h4 is also It is 1.5 mm. The length L2 of the outer housing 50 is 39 mm.

The diameter φ3 of the first flange portion mounting groove portion 51 in FIG. 4A is 22.13 mm, which is slightly larger than the diameter 22 mm of the first flange portion 22 of the first flanged bearing 20 (D1 in FIG. 2). In the present embodiment, the diameters of the first flange portion 22 and the second flange portion 32 (D1 in FIG. 2) of the first flanged bearing 20 and the second flanged bearing 30 are the same, so that the second The diameter of the flange portion mounting groove portion 52 is also 22.13 mm.

The first flanged bearing 20, the second flanged bearing 30, and the shaft 60 are assembled to the inner housing 40 and the outer housing 50 by the following procedure. As a result, the shaft 60, the first flanged bearing 20, and the second flanged bearing 30 are fixed to the inner housing 40 and the outer housing 50.

As shown in FIG. 1, the shaft 60 has a small diameter portion 61 that matches the inner diameter of the second flanged bearing 30 (d in FIG. 2) of 8 mm and the inner diameter of the first flanged bearing 20 (d in FIG. 2) of 10 mm. The large-diameter portion 62 corresponding to the above is a columnar object having a circular cross section formed continuously by the step portion 63. When two of only one of them are used, the step portion 63 is unnecessary.

First, the second bearing main body 31 of the bearing 30 with the second flange is passed from the side where the second flange mounting groove 52 is formed of the outer housing 50, and the second flange 32 is inserted into the second flange mounting groove 52. To do.

Next, the inner housing 40 is inserted into the outer housing 50 from the second bearing body 31 side of the second flanged bearing 30, and the outer ring portion 13 from the second flange 32 side of the second flanged bearing 30 (FIG. 2). ), The second bearing main body 31 of the second flanged bearing 30 is press-fitted into the second bearing main body mounting groove 42 of the inner housing 40.

At this time, since the thickness of the closest portion between the second bearing main body mounting groove 42 of the inner housing 40 and the outer surface of the inner housing 40 is 0.001 mm, the second bearing 30 with the second flange has a thickness of 0.001 mm. When the bearing main body 31 is press-fitted into the second bearing main body mounting groove 42, the second bearing main body mounting groove 42 is widened to the outside, so that the second bearing main body mounting groove 42 is attached to the second bearing main body 31. The pressure from the side surface can be relaxed.

Next, while pressing the inner ring portion 14 (FIG. 2) from the second flange portion 32 side of the second flanged bearing 30, the small diameter portion 61 of the shaft 60 is pressed from the second bearing main body portion 31 side of the second flanged bearing 30. It is inserted into the inner housing 40 and passed through the second bearing main body 31 of the second flanged bearing 30. Then, the step portion 63 completes the mounting of the shaft 60 on the second flanged bearing 30.

Next, the bearing 20 with the first flange is pressed against the large diameter portion 62 of the exposed shaft 60 from the side of the first bearing body 21 to the inner ring portion 14 and the outer ring portion 13 (FIG. 2) of the bearing 20 with the first flange. Insert and pass while.

Then, the first bearing main body 21 of the first flanged bearing 20 is press-fitted into the first bearing main body mounting groove 41 of the inner housing 40, and the first flange 22 of the first flanged bearing 20 is outside. It is inserted into the first flange portion mounting groove 51 of the housing 50, and the mounting / fixing of the second flanged bearing 30 and the first flanged bearing 20 to the inner housing 40 and the outer housing 50 is completed (FIG. 1).

At this time, the thickness of the closest contact portion between the first bearing main body mounting groove 41 of the inner housing 40 and the outer surface of the inner housing 40 is 0.001 mm, so that the first bearing main body is mounted at the time of press fitting. The groove 41 can be widened outward to relieve the pressure from the side surface of the first bearing body mounting groove 41 on the first bearing body 21.

In the present embodiment, there is a gap between the outer surface of the inner housing 40 and the inner surface of the outer housing 50, but since both the inner housing 40 and the outer housing 50 have a square cross section, they are inside. The corners of the outer surface of the housing 40 abut against the inner surface of the outer housing 50 to secure the space between the inner housing 40 and the outer housing 50. Further, the above-mentioned gap facilitates insertion of the inner housing 40 into the outer housing 50.

Further, the above gap is formed in the inner housing when the first bearing main body 21 and the second bearing main body 31 are press-fitted into the first bearing main body mounting groove 41 and the second bearing main body mounting groove 42 of the inner housing 40. Allows the outer surface of 40 to spread outward.

Then, a stator core in which a coil is wound around the outer circumference of the outer housing 50 in FIG. 1 and a substrate for wiring from the coil are attached, and a rotor cup with a permanent magnet attached to the inner wall surface side thereof is press-fitted onto the shaft. As a result, the outer rotor type rotary electric machine is assembled by attaching the permanent magnet and the coil so as to face each other.

The practice of the present invention is not limited to the above embodiment, and various modifications can be made as long as the object of the present invention is not deviated.

For example, in the present embodiment, the shaft 60 is formed by continuously forming a small diameter portion 61 that matches the inner diameter of the second flanged bearing 30 and a large diameter portion 62 that matches the inner diameter of the first flanged bearing 20 by the stepped portion 63. It was attached from the bearing 30 with the second flange, but after forming a step on the bearing 20 with the first flange and inserting the shaft 60 into the bearing 20 with the first flange, the outer housing 50 , The inner housing 40 may be attached to the first flanged bearing 20 in this order, and then the second flanged bearing 30 may be attached.

20 Bearing with 1st flange 21 1st bearing main body 22 1st flange 30 2nd bearing with flange 31 2nd bearing main body 32 2nd flange 40 Inner housing 41 1st bearing main body mounting groove 42 2nd bearing main body Part Mounting groove 43 Cutting hole 50 Outer housing 51 1st flange mounting 52 2nd flange mounting 60 Shaft 63 Step

Claims (3)

A bearing fixing structure in an outer rotor type rotary electric machine in which a rotor is arranged outside the stator and the shaft and the rotor are rotated via a bearing.
The bearing is a flanged bearing.
The housing accommodating the flanged bearing is composed of an inner housing in which the shaft is arranged inside and an outer housing in which the shaft is arranged outside the inner housing.
The inner housing and the outer housing both have an outer surface and an inner surface, and have a tubular shape having a square cross section on both the outer surface and the inner surface.
The outer housing is longer than the inner housing in the insertion direction of the shaft.
At both ends of the inner housing, an arc-shaped bearing body mounting groove corresponding to the outer diameter and width of the bearing body of the flanged bearing is formed at the center of each side having a square cross section.
At both ends of the outer housing, an arc-shaped flange mounting groove corresponding to the outer diameter of the flange of the flanged bearing is formed at the center of each side having a square cross section.
The flanged bearing is provided so that the bearing body faces each other.
The bearing body of the flanged bearing is press-fitted into the bearing body mounting groove of the inner housing.
A bearing fixing structure in an outer rotor type rotary electric machine, wherein the flange portion of the flanged bearing is mounted in the flange portion mounting groove portion of the outer housing. The bearing fixing structure in the outer rotor type rotary electric machine according to claim 1, wherein the material of the inner housing and the outer housing is aluminum. The outer rotor type according to claim 2, wherein in the inner housing, the thickness of the closest portion between the outer surface of the inner housing and the bearing body portion mounting groove portion is 0.001 mm or more and 0.500 mm or less. Fixed structure of bearings in rotary electric machines.

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