JP2009100573A - Brushless motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a brushless motor capable of reducing the cost. <P>SOLUTION: In this brushless motor 10, an outer ring 40B of a second ball bearing 40 is inserted into the inside of a cylindrical portion 42, held by an axial hole portion 36 for fitting and holding. The cylindrical portion 42 is provided with a second ball bearing support portion 44A and a second support portion 56 on one side (Z1 side) and the other side (Z2 side) in an axial direction of a rotating shaft 26. The outer ring 40B of the second bearing 40 is supported by the second ball bearing support portion 44A and the second support portion 56 from one side and the other side in the axial direction of the rotating shaft 26. In addition, the outer ring 38B of a first ball bearing 38 is inserted into the axial hole portion 36 of a stator 14 for fitting and holding, while being pressed against to one side, in the axial direction of the rotating shaft 26 relative to a pressing member support portion 44C by a wave washer 46. Accordingly, this structure eliminates the need for a bush that holds the first ball bearing 38, and thereby reducing the number of parts and the number of man-hours to achieve cost reduction. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a brushless motor, and more particularly, to a brushless motor configured to rotatably support a rotating shaft with a pair of ball bearings.

  Conventionally, as this type of brushless motor, for example, there is the following (for example, see Patent Document 1). For example, in the example described in Patent Document 1, a pair of ball bearings is disposed between the housing and the rotor hub with an interval in the axial direction of the motor. The outer ring of one ball bearing is mounted on the hub body, and the outer ring of the other ball bearing is mounted on a sleeve member (bush).

Although not used in the example described in Patent Literature 1, some brushless motors of this type use a pressing member for applying a preload to the pair of ball bearings in the axial direction of the motor. .
JP 2000-145793 A

  However, in the example described in Patent Document 1, a sleeve member (bush) is necessary to hold the other ball bearing. For this reason, the number of parts and manufacturing man-hours increase by using this sleeve member. Therefore, there is room for improvement in order to reduce the number of parts and the number of manufacturing steps to reduce the cost.

  The present invention has been made in view of the above problems, and an object thereof is to provide a brushless motor capable of reducing the cost.

  In order to solve the above-mentioned problem, the brushless motor according to claim 1 is formed along a rotation shaft, a rotor fixed to one axial direction of the rotation shaft, and an axial direction of the rotation shaft. The rotating shaft has an axial hole portion that is rotatably accommodated, a stator that forms a rotating magnetic field for rotating the rotor, an inner ring is fixed to one axial direction of the rotating shaft, and an outer ring is A first ball bearing held in the axial hole, a second ball bearing in which an inner ring is fixed to the other axial side of the rotary shaft, and the axial direction formed along the axial direction of the rotary shaft A cylindrical portion that is held in the hole and in which the outer ring of the second ball bearing is held; and an outer ring of the second ball bearing that is provided on one side of the cylindrical portion in the axial direction of the rotating shaft. Shi A first support part that is supported from one axial side of the shaft, and an outer ring of the second ball bearing that is provided on the other axial side of the rotary shaft in the cylindrical part and supports the outer ring of the second ball bearing from the other axial side of the rotary shaft. A center piece configured to include a second support portion, and a pressing member that presses the outer ring of the first ball bearing against the first support portion toward the one axial side of the rotary shaft. It is characterized by that.

  According to the brushless motor of the first aspect, the outer ring of the second ball bearing is held inside the cylindrical portion held in the axial hole portion, and one axial direction side of the rotary shaft in the cylindrical portion and The first support portion and the second support portion provided on the other side are supported from one side and the other side in the axial direction of the rotating shaft. Further, the outer ring of the first ball bearing is held in the axial hole portion of the stator and is pressed against the first support portion toward the one axial direction of the rotary shaft by the pressing member. Therefore, a sleeve member (bush) for holding the first ball bearing or the second ball bearing is unnecessary. Thereby, since a number of parts and a manufacturing man-hour can be reduced, cost can be reduced.

  The brushless motor according to claim 2 is the brushless motor according to claim 1, wherein the pressing member is a wave washer.

  According to the brushless motor of the second aspect, the outer ring of the first ball bearing can be pressed against one side in the axial direction of the rotating shaft against the first support portion by using the wave washer as the pressing member.

  The brushless motor according to claim 3 is the brushless motor according to claim 1 or 2, wherein the center piece includes a plate portion that closes an opening portion on the other axial side of the rotary shaft in the cylindrical portion. And the second support part is provided on the plate part.

  According to the brushless motor according to claim 3, the second ball bearing is provided by the second support portion provided in the plate portion simultaneously with the step of closing the opening portion on the other axial side of the rotating shaft in the cylindrical portion with the plate portion. The outer ring can be supported from the other axial side of the rotary shaft. This reduces the number of manufacturing steps compared to a configuration in which the step of closing the opening of the cylindrical portion with the plate portion and the step of supporting the outer ring of the second ball bearing by the second support portion need to be performed separately. Cost can be reduced.

  A brushless motor according to a fourth aspect of the present invention is the brushless motor according to the first or second aspect, wherein the second support portion is configured such that the other axial direction of the rotating shaft in the cylindrical portion is caulked radially inward. It is characterized by being a crimped portion formed.

  According to the brushless motor of the fourth aspect, the second ball is formed by the caulking portion as the second support portion only by caulking the other axial side of the rotating shaft in the cylindrical portion radially inward. The outer ring of the bearing can be supported from the other axial side of the rotating shaft. This eliminates the need for a member for supporting the outer ring of the second ball bearing from the other axial side of the rotary shaft, thereby further reducing the number of components.

  The brushless motor according to claim 5 is the brushless motor according to any one of claims 1 to 4, wherein the cylindrical portion is provided on the other axial side of the rotary shaft with respect to the first ball bearing. It is characterized by that.

  According to the brushless motor of the fifth aspect, the cylindrical portion is provided on the other axial side of the rotary shaft with respect to the first ball bearing. Therefore, for example, the length of the cylindrical portion in the axial direction of the rotary shaft can be shortened as compared with the configuration in which the first ball bearing and the second ball bearing are disposed inside the cylindrical portion. Thereby, the material cost of a centerpiece can be reduced, and the cost of the whole motor can be reduced by extension.

  The brushless motor according to claim 6 is the brushless motor according to any one of claims 1 to 5, wherein the first support portion has an outer ring of the second ball bearing in an axial direction of the rotary shaft. It has the 2nd ball bearing support part supported from one side, and the press member support part which supports the said press member from the axial direction other side of the said rotating shaft, It is characterized by the above-mentioned.

  According to the brushless motor of the sixth aspect, the second ball bearing support portion that supports the outer ring of the second ball bearing from one axial direction side of the rotating shaft, and the pressing member is supported from the other axial direction side of the rotating shaft. The pressing member support portion is provided on the common first support portion. Therefore, the center piece can be reduced in size as compared with the configuration in which the second ball bearing support portion and the pressing member support portion are provided at different locations of the center piece. Thereby, the material cost of a centerpiece can be reduced, and the cost of the whole motor can be reduced by extension.

  The brushless motor according to claim 7 is the brushless motor according to any one of claims 1 to 6, wherein the brushless motor is for a vehicle in which a blower fan is provided on the rotor so as to be integrally rotatable. It is a fan motor.

  According to the brushless motor of the seventh aspect, since the cost can be reduced, an inexpensive vehicle fan motor can be provided on the market.

  Hereinafter, an embodiment of a brushless motor of the present invention will be described with reference to the drawings.

  FIG. 1 is a side sectional view showing the overall configuration of a brushless motor 10 according to an embodiment of the present invention. The brushless motor 10 shown in this figure is suitably used as a vehicle fan motor for cooling a radiator mounted on a vehicle such as a passenger car, for example, and includes a rotor 12, a stator 14, and a centerpiece. 16 as a main configuration.

  The rotor 12 includes a bottomed cylindrical rotor housing 18 and a rotor magnet 20. A cylindrical fitting portion 24 is formed at the center of the bottom portion 22 of the rotor housing 18, and one axial direction side (Z1 side) of the rotary shaft 26 is inserted into the fitting portion 24 and fitted. It is fixed.

  A rotor magnet 20 arranged in an annular shape along the circumferential direction of the rotary shaft 26 is fixed to the inner peripheral surface of the cylindrical portion 28 of the rotor housing 18, and the outer peripheral surface of the cylindrical portion 28 of the rotor housing 18 is The blower fan 30 is mounted so as to be integrally rotatable.

  The stator 14 includes a stator coil 32 and a stator core 34. The stator coil 32 is wound around a plurality of teeth formed on the stator core 34 and is electrically connected to a control circuit (not shown). The stator 14 is configured to form a rotating magnetic field for rotating the rotor 12 in accordance with a control signal from a control circuit (not shown).

  An axial hole 36 is formed in the central portion of the stator core 34 along the axial direction of the rotary shaft 26, and the rotary shaft 26 is rotatably accommodated in the axial hole 36.

  An inner ring 38A of the first ball bearing 38 is press-fitted and fixed to the rotating shaft 26 on one side (Z1 side) in the axial direction, and an inner ring 40A of the second ball bearing 40 is press-fitted and fixed on the other side (Z2 side) in the axial direction. Has been. An outer ring 38B of the first ball bearing 38 is inserted and held in the axial hole 36, and an outer ring 40B of the second ball bearing 40 is inside a cylindrical part 42 formed in the center piece 16 described later. It is inserted and held in (hole).

  The center piece 16 is made of iron and is disposed on the other side in the axial direction of the rotary shaft 26 with respect to the rotor 12. A cylindrical portion 42 extending along the axial direction of the rotary shaft 26 is formed at the center portion of the center piece 16, and one axial direction side of the rotary shaft 26 in the cylindrical portion 42 in the axial direction of the rotary shaft 26. A first support portion 44 is formed between the first ball bearing 38 and the second ball bearing 40.

  The first support portion 44 includes a second ball bearing support portion 44A, a cylindrical portion 44B, and a pressing member support portion 44C.

  The second ball bearing support portion 44 </ b> A extends from one axial direction side of the rotation shaft 26 in the cylindrical portion 42 toward the rotation shaft 26 side, and the outer ring 40 </ b> B of the second ball bearing 40 extends in the axial direction of the rotation shaft 26. Support from one side.

  The cylindrical portion 44B is arranged offset to the rotating shaft 26 side with respect to the cylindrical portion 42, and extends from the second ball bearing support portion 44A toward one axial direction of the rotating shaft 26. The center piece 16 is fixed integrally with the stator core 34 by inserting the cylindrical portion 44B and the above-described cylindrical portion 42 into the axial hole portion 36 and fitting with each other.

  The pressing member support portion 44C extends from the axial direction one side of the rotating shaft 26 in the cylindrical portion 44B toward the rotating shaft 26 side. The pressing member support portion 44C is arranged offset to the rotary shaft 26 side with respect to the second ball bearing support portion 44A, and a wave washer 46 as a pressing member interposed between the first ball bearing 38 and the second ball bearing support portion 44A. A radially inner portion is supported from the other axial side of the rotary shaft 26.

  The radially outer portion of the wave washer 46 is in contact with the outer ring 38B of the first ball bearing 38. The wave washer 46 rotates the outer ring 38B of the first ball bearing 38 against the pressing member support portion 44C. Is pressed to one side in the axial direction. As a result, a preload is applied to the outer ring 38B of the first ball bearing 38 and the inner ring 40A of the second ball bearing 40 as indicated by an arrow P in FIG.

  Further, the center piece 16 described above is provided with a disk-shaped plate-like portion 48 that spreads radially outward from the outer peripheral portion on the other axial side of the rotating shaft 26 in the cylindrical portion 42. Further, the above-described center piece 16 is configured to have a disk-shaped plate portion 50, and the plate portion 50 is integrally fixed to the plate-shaped portion 48.

  The plate portion 50 is configured to have a closing portion 54 that closes the opening 52 on the other axial side of the rotary shaft 26 in the cylindrical portion 42, and the closing portion 54 includes an outer ring of the second ball bearing 40. A protruding second support portion 56 that supports 40B from the other axial side of the rotary shaft 26 is formed.

  And according to the brushless motor 10 which consists of the said structure, there exist the following peculiar effects.

  Here, in order to clarify the effect of the brushless motor 10 according to the embodiment of the present invention, first, a brushless motor 110 according to a comparative example will be described.

  FIG. 3 is a side sectional view showing the overall configuration of the brushless motor 110 according to the comparative example. In addition, in the brushless motor 110 according to this comparative example, the same reference numerals are used for the sake of convenience for the configurations having the same names as those of the brushless motor 10 according to the embodiment of the present invention described above.

  In the brushless motor 110 according to this comparative example, the cylindrical portion 42 of the center piece 16 is extended to one side in the axial direction of the rotary shaft 26, and the first ball bearing 38 and the second ball bearing 40 are arranged inside the cylindrical portion 42. It is inserted and held in (hole).

  The first ball bearing 38 includes a first support portion 44 provided on one side in the axial direction of the rotary shaft 26 in the cylindrical portion 42, and a bush 112 inserted into and held in the cylindrical portion 42. 26 is supported from one axial side (Z1 side) and the other side (Z2 side).

  The outer ring 40 </ b> B of the second ball bearing 40 is pressed against the plate portion 50 toward one axial direction of the rotary shaft 26 by a wave washer 46 interposed between the second ball bearing 40 and the plate portion 50. As a result, as indicated by an arrow P in FIG. 3, preload is applied to the inner ring 38 </ b> A of the first ball bearing 38 and the outer ring 40 </ b> B of the second ball bearing 40.

  However, in the brushless motor 110 according to this comparative example, the bush 112 is required to support the first ball bearing 38 from the other axial side of the rotary shaft 26. For this reason, the number of parts and manufacturing man-hours increase by using this bush 112. Therefore, there is room for improvement in order to reduce the number of parts and the number of manufacturing steps to reduce the cost.

  In the brushless motor 110 according to this comparative example, the bush 112 is omitted, and instead, a caulking portion 114 (illustrated by an imaginary line by a two-dot chain line) is caulked on a part of the inner peripheral surface of the cylindrical portion 42. It is also conceivable that the outer ring 38B of the first ball bearing 38 is supported from the other side in the axial direction of the rotating shaft 26 by the caulking portion 114.

  However, in this case, the caulking portion 114 is formed at a deep position from the opening 52 of the cylindrical portion 42. For this reason, it is necessary to process the inner wall from the inner peripheral surface of the cylindrical portion 42. However, the processing is very difficult.

  In the brushless motor 110 according to this comparative example, it may be considered that the bush 112 is simply omitted. However, in this case, the load of the rotating shaft 26, the first ball bearing 38, the second ball bearing 40, the rotor 12, etc. acts on the wave washer 46. Therefore, it is necessary to increase the durability of the wave washer 46, and it is difficult to reduce the cost.

  On the other hand, according to the brushless motor 10 according to the embodiment of the present invention shown in FIG. 1, the outer ring 40 </ b> B of the second ball bearing 40 is inserted into the cylindrical portion 42 held in the axial hole portion 36. One of the axial directions of the rotary shaft 26 is held by the second ball bearing support portion 44A and the second support portion 56 provided on one side and the other side of the rotary shaft 26 in the cylindrical portion 42. It is supported from the side and the other side.

  Further, the outer ring 38B of the first ball bearing 38 is inserted and held in the axial hole 36 of the stator 14 and is held by the wave washer 46 toward one side in the axial direction of the rotary shaft 26 with respect to the pressing member support 44C. It is pressed.

  Therefore, the bush 112 for holding the first ball bearing 38 is unnecessary. Thereby, since a number of parts and a manufacturing man-hour can be reduced, cost can be reduced.

  Furthermore, according to the brushless motor 10 according to an embodiment of the present invention, the step of closing the opening 52 on the other axial side of the rotating shaft 26 in the cylindrical portion 42 with the plate portion 50 (that is, the plate portion 50 is plate-shaped). At the same time, the outer ring 40B of the second ball bearing 40 can be supported from the other axial side of the rotary shaft 26 by the second support portion 56 provided on the plate portion 50.

  Thereby, compared with the structure which needs to perform separately the process of obstruct | occluding the opening part 52 of the cylindrical part 42 with the plate part 50, and the process of supporting the outer ring | wheel 40B of the 2nd ball bearing 40 by the 2nd support part 56. In addition, since the number of manufacturing steps can be reduced, the cost can be reduced.

  Further, according to the brushless motor 10 according to the embodiment of the present invention, the cylindrical portion 42 is provided on the other axial side of the rotary shaft 26 with respect to the first ball bearing 38. The outer ring 38B of the first ball bearing 38 is held by the axial hole 36 of the stator 14, and only the outer ring 40B of the second ball bearing 40 is held by the cylindrical portion 42.

  Therefore, for example, as compared with the configuration in which the first ball bearing 38 and the second ball bearing 40 are arranged inside the cylindrical portion 42 as in the brushless motor 110 according to the comparative example, the cylindrical portion in the axial direction of the rotary shaft 26. The length of 42 can be shortened (L1 <L2). Thereby, the material cost of the center piece 16 can be reduced, and consequently the cost of the entire motor can be reduced.

  According to the brushless motor 10 according to the embodiment of the present invention, for example, even when the cylindrical portion 42 is formed by drawing, the length of the cylindrical portion 42 in the axial direction of the rotary shaft 26 can be shortened. Therefore, the processing accuracy of the cylindrical portion 42 can be improved as compared with the configuration in which the length of the cylindrical portion 42 is long like the brushless motor 110 according to the comparative example. Thereby, the holding | maintenance precision of the 2nd ball bearing 40 by the cylindrical part 42 can be improved, and the rotation balance of the rotor 12 can be made favorable by extension.

  Further, according to the brushless motor 10 according to the embodiment of the present invention, the second ball bearing support portion 44 </ b> A that supports the outer ring 40 </ b> B of the second ball bearing 40 from the one axial side of the rotary shaft 26, and the wave washer 46 are provided. 44 C of pressing member support parts supported from the other axial side of the rotating shaft 26 are provided in the common 1st support part 44, respectively.

  Therefore, the center piece 16 can be reduced in size as compared with the configuration in which the second ball bearing support portion 44 </ b> A and the pressing member support portion 44 </ b> C are provided at different locations of the center piece 16. Thereby, the material cost of the center piece 16 can be reduced, and consequently the cost of the entire motor can be reduced.

  As described above in detail, according to the brushless motor 10 according to an embodiment of the present invention, the cost can be reduced, and therefore, an inexpensive vehicle fan motor can be provided on the market.

  As mentioned above, although one Embodiment of this invention was described, this invention is not limited above, Of course, it can change and implement variously within the range which does not deviate from the main point. .

  For example, in the above embodiment, the center piece 16 is provided with the plate portion 50, and the second support portion 56 formed on the plate portion 50 causes the outer ring 40 </ b> B of the second ball bearing 40 to move from the other axial side of the rotary shaft 26. Although it was configured to be supported, it may be configured as follows.

  Here, in FIG. 2, a modified example of the brushless motor 10 according to one embodiment of the present invention is shown in a side sectional view. That is, as shown in this drawing, the other axial side of the rotating shaft 26 in the cylindrical portion 42 (near the opening 52) is caulked radially inward to form a caulking portion 58 as a second support portion, The caulking portion 58 may be configured so that the outer ring 40 </ b> B of the second ball bearing 40 is supported from the other axial side of the rotary shaft 26.

  According to this modification, only the other axial side of the rotating shaft 26 in the cylindrical portion 42 is caulked radially inward as the caulking portion 58, and the second ball bearing is formed by the caulking portion 58 as the second support portion. Forty outer rings 40 </ b> B can be supported from the other axial side of the rotary shaft 26. This eliminates the need for the plate portion 50 for supporting the outer ring 40B of the second ball bearing 40 from the other axial side of the rotary shaft 26, thereby further reducing the number of components.

  Moreover, according to this modification, the position where the caulking portion 58 is formed is the other side in the axial direction of the rotating shaft 26 in the cylindrical portion 42 (in the vicinity of the opening portion 52), so that caulking is easy.

  Moreover, in the said embodiment, although the wave washer was used as a press member, of course, other members may be used.

  Moreover, in the said embodiment, although the brushless motor 10 was supposed to be used as a fan motor for vehicles, it is needless to say that it may be used for other uses.

It is side surface sectional drawing which shows the whole structure of the brushless motor which concerns on one Embodiment of this invention. It is side surface sectional drawing which shows the modification of the brushless motor which concerns on one Embodiment of this invention. It is side surface sectional drawing which shows the whole structure of the brushless motor which concerns on a comparative example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Brushless motor, 12 ... Rotor, 14 ... Stator, 16 ... Centerpiece, 26 ... Rotating shaft, 30 ... Fan for blowing, 34 ... Stator core, 36 ... Axial hole part, 38 ... First ball bearing, 40 ... First Double ball bearing, 42 ... cylindrical part, 44 ... first support part, 44A ... second ball bearing support part, 44B ... cylindrical part, 44C ... pressing member support part, 46 ... wave washer (pressing member), 50 ... plate Part 56 ... second support part 58 ... caulking part (second support part)

Claims (7)

A rotating shaft;
A rotor fixed to one axial side of the rotating shaft;
A stator that is formed along the axial direction of the rotary shaft and has an axial hole in which the rotary shaft is rotatably accommodated, and that forms a rotating magnetic field for rotating the rotor;
A first ball bearing in which an inner ring is fixed to one axial side of the rotating shaft and an outer ring is held in the axial hole;
A second ball bearing in which an inner ring is fixed to the other axial side of the rotary shaft;
A cylindrical portion formed along the axial direction of the rotating shaft and held in the axial hole portion and holding the outer ring of the second ball bearing therein, and the axial direction of the rotating shaft in the cylindrical portion A first support portion provided on one side for supporting an outer ring of the second ball bearing from one axial side of the rotary shaft; and a second support portion provided on the other axial side of the rotary shaft in the cylindrical portion. A center piece configured to have a second support portion that supports the outer ring of the ball bearing from the other axial side of the rotating shaft;
A pressing member that presses the outer ring of the first ball bearing against the first support portion toward the one axial side of the rotary shaft;
A brushless motor characterized by comprising: The pressing member is a wave washer,
The brushless motor according to claim 1. The center piece has a plate portion that closes an opening on the other axial side of the rotating shaft in the cylindrical portion,
The second support part is provided on the plate part,
The brushless motor according to claim 1, wherein the motor is a brushless motor. The second support part is a caulking part formed by caulking the other axial side of the rotating shaft in the cylindrical part radially inward.
The brushless motor according to claim 1, wherein the motor is a brushless motor. The cylindrical portion is provided on the other axial side of the rotary shaft with respect to the first ball bearing.
The brushless motor as described in any one of Claims 1-4 characterized by the above-mentioned. The first support part is
A second ball bearing support portion that supports the outer ring of the second ball bearing from one axial side of the rotary shaft;
A pressing member support that supports the pressing member from the other axial side of the rotating shaft;
Having
The brushless motor according to any one of claims 1 to 5, wherein: The brushless motor is a vehicle fan motor in which a blower fan is provided on the rotor so as to be integrally rotatable.
The brushless motor according to claim 1, wherein the motor is a brushless motor.

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