JP2012225454A - Drive unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve reduction in number of parts, reduction in size in a radial direction, and simplification of structure.SOLUTION: A drive unit 10 includes: a pair of fixed shafts 12, 14; a rotor 16 having an output shaft 34; a stator 18 disposed radially outside of the rotor 16; a motor housing 20 fixed to one fixed shaft 12 and the stator 18 and rotatably supporting the output shaft 34 through bearings 56, 60; an external gear 22 rotatably supported by an eccentric shaft 36 eccentrically disposed to the output shaft 34, through a bearing 62, and having a plurality of transmission holes 64; a carrier 24 having a plurality of inner pins 66 eccentrically inserted into the plurality of transmission holes 64, and a carrier body 68 supporting the plurality of inner pins 66 and formed integrally with the other fixed shaft 14; a hub 26 rotatable with respect to the pair of fixed shafts 12, 14 by bearings 84, 88; and an internal gear 28 internally meshed with the external gear 22 and fixed to be rotatably integrally with the hub 26.

Description

  The present invention relates to a drive unit.

  2. Description of the Related Art Conventionally, a fixed shaft (31) and an output shaft (21) rotatably supported on the fixed shaft (31) via a bearing are provided, and the output shaft (21) is rotatably supported with respect to a motor housing. A motor (2) having a bearing for rotating, a cycloid gear (42) rotatably supported by an eccentric shaft (22) provided on the output shaft (21) via a bearing (424), and the cycloid gear ( A reduction plate (43) having a pin (431) inserted into a conduction hole (423) formed in 42) and rotatably supported by a fixed shaft (31) via a bearing (435); A hub (1) that can rotate integrally with the speed reducer (43), and a rotating needle fixing ring (41) that is fixed to the motor (2) in a non-rotatable state and meshes with the cycloid gear (42). Cycloid deceleration equipped Electric wheel motor is known (e.g., see Patent Document 1).

JP 2001-140996 A (FIG. 6)

  However, the cycloid reduction type electric wheel motor has the following problems.

  That is, the fixed shaft (31) is inserted inside the output shaft (21). For this reason, the bearing which supports an output shaft (21) rotatably with respect to this fixed shaft (31) is needed, and a number of parts increases.

  A bearing that rotatably supports the output shaft (21) with respect to the fixed shaft (31) and a bearing that rotatably supports the output shaft (21) with respect to the motor housing are disposed concentrically. Yes. For this reason, the motor (2) is enlarged in the radial direction.

  Further, since the rotating needle fixing ring (41) is fixed to the motor (2) in a non-rotatable state, the speed reducer (43) needs to be rotatable with respect to the fixed shaft (31), and the structure is To be complicated.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a drive unit that can reduce the number of parts, can be downsized in the radial direction, and can simplify the structure. .

  In order to solve the above-mentioned problem, the drive unit according to claim 1 is arranged coaxially with each other, and a pair of fixed shafts fixed to the outside, respectively, and the pair of fixed shafts between the pair of fixed shafts A rotor having an output shaft arranged coaxially with the rotor, a stator formed in an annular shape and provided radially outside the rotor, and fixed to one of the pair of fixed shafts, and fixed to the stator And a motor housing that rotatably supports the output shaft via a first bearing, and an eccentric shaft that is provided in an eccentric state on the output shaft and is rotatably supported via a second bearing. An external gear in which a plurality of conduction holes are formed side by side in the rotation direction, a plurality of inner pins inserted into the plurality of conduction holes in an eccentric state, and the pair of fixed pins that support the plurality of inner pins Installed on the other side of the shaft so that it can rotate integrally. A carrier body, a rotating member that can be rotated by a third bearing with respect to the pair of fixed shafts, and the external gear is inscribed and meshed with the rotating member. An internal gear that is fixed in a possible manner.

  According to this drive unit, the pair of fixed shafts are arranged coaxially with each other, and the output shaft of the rotor is arranged between the pair of fixed shafts. For this reason, the bearing which supports an output shaft rotatably with respect to a pair of fixed shaft becomes unnecessary, and can reduce a number of parts.

  In addition, as described above, by eliminating the need for bearings that rotatably support the output shaft with respect to the pair of fixed shafts, it is possible to avoid the concentric arrangement of a plurality of bearings, so that the drive unit can be reduced in diameter. It can be downsized in the direction.

  Furthermore, since the internal gear is connected to the rotating member so as to be integrally rotatable, the carrier body is provided on the other of the pair of fixed shafts so as to be integrally rotatable, so that the structure can be simplified.

  The drive unit according to claim 2 is the drive unit according to claim 1, wherein the motor housing has an opposing wall portion facing the carrier body in the axial direction of the output shaft, and the plurality of inner pins Both end portions in the axial direction are fixed to the carrier body and the opposing wall portion.

  According to this drive unit, since both end portions in the axial direction of the inner pin are supported by the carrier body and the opposing wall portion, the support rigidity of the inner pin can be increased. Thereby, vibration and noise can be suppressed.

  In addition, when both end portions in the axial direction of the inner pin are supported by the carrier main body and the opposing wall portion, the durability of the inner pin can be improved.

  The drive unit according to claim 3 is the drive unit according to claim 2, wherein the carrier penetrates in the axial direction of the inner pin coaxially with at least one of the plurality of inner pins. A plurality of press-fitting holes are formed in the opposing wall portion, and the tip portions of the plurality of inner pins are press-fitted, and are coaxial with at least the through-holes of the plurality of press-fitting holes. A screw hole portion is formed in the press-fitting hole located at, and a bolt is inserted into the through hole and the tip of the bolt is screwed into the screw hole portion of the carrier body and the opposing wall portion. Thus, they are fixed to each other.

  According to this drive unit, by screwing the bolt into the screw hole portion, it is possible to press-fit the respective distal end portions of the plurality of inner pins into the plurality of press-fit holes. As a result, workability when attaching the carrier to the motor housing (for example, workability when pressurizing each of the plurality of inner pins into the plurality of press-fitting holes) can be improved. .

  Moreover, the positioning accuracy of the carrier and the motor housing can be improved by press-fitting the tip portions of the plurality of inner pins into the plurality of press-fitting holes. Thereby, the coaxial precision of the motor part which has a rotor, a stator, and a motor housing, and the reduction gear mechanism which has an external gear, a carrier, and an internal gear can be ensured.

  Furthermore, since the carrier main body and the opposing wall portion of the motor housing are fixed to each other by bolts and screw hole portions, the rigidity of mounting the carrier to the motor housing can be increased. Thereby, vibration and noise can be further reduced.

  The drive unit according to claim 4 is the drive unit according to any one of claims 1 to 3, wherein the motor housing is opposed to the carrier body in the axial direction of the output shaft. The opposing wall is formed with an accommodation recess that is inserted inside the stator and opens toward the carrier body, and the internal gear and the external gear are accommodated in the accommodation recess. It is configured.

  According to this drive unit, a housing recess inserted into the stator is formed in the opposing wall portion of the motor housing, and an internal gear and an external gear are housed in the housing recess. Therefore, since the space where the stator is not used can be used effectively, the drive unit can be reduced in the axial direction.

  The drive unit according to claim 5 is the drive unit according to any one of claims 1 to 4, wherein a fixing portion that fixes the rotating member and the internal gear is more than the internal gear. Is also provided on the radially outer side.

  According to this drive unit, the fixed portion that connects the rotating member and the internal gear is provided on the outer side in the radial direction than the internal gear, whereby the moment length of the force transmitted from the internal gear to the rotating member is increased. Has been secured for a long time. Thereby, the structure of a fixing | fixed part can be simplified, for example.

  The drive unit according to claim 6 is the drive unit according to any one of claims 1 to 5, wherein the rotating member is the rotor, the stator, the motor housing, the carrier, and the external teeth. A case that houses a gear and the internal gear, and that has an opening on the other side of the pair of fixed shafts, and a cover that closes the opening, and the carrier is a member of the pair of fixed shafts. One of the pair of fixed shafts, the first bearing, the rotor, the stator, and the motor housing are assembled with each other to form a motor assembly, the eccentric shaft, The two bearings and the external gear are assembled together to form a gear assembly, and the cover, the third bearing, and the internal gear are assembled together to form a cover assembly. It has a configuration that make up the assembly.

  According to this drive unit, since the motor assembly, the gear assembly, and the cover assembly that are assembled in advance are provided, the entire assembly operation can be facilitated.

It is side surface sectional drawing of the drive unit which concerns on one Embodiment of this invention. It is a disassembled perspective view of the drive unit shown by FIG. FIG. 3 is a perspective view of the cover assembly shown in FIG. 2.

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

  Here, as an example, an example in which the drive unit of the present invention is used as a power source for an electric bicycle will be described.

  As shown in FIG. 1, a drive unit 10 according to an embodiment of the present invention includes a pair of fixed shafts 12, 14, a rotor 16, a stator 18, a motor housing 20, an external gear 22, and a carrier. 24, a hub 26 as an example of a rotating member, and an internal gear 28 are provided as main components.

  The pair of fixed shafts 12 and 14 are arranged coaxially with each other. Screw portions 12A and 14A are formed on the pair of fixed shafts 12 and 14, respectively, and nuts 30 and 32 are screwed onto the screw portions 12A and 14A, respectively. One fixed shaft 12 is fixed to the outside using a nut 30, and the other fixed shaft 14 is fixed to the outside using a nut 32. The outside in this case is, for example, a bicycle body.

  The rotor 16 constitutes a brushless motor together with a stator 18 described later. The rotor 16 has an output shaft 34 disposed coaxially with the pair of fixed shafts 12 and 14 between the pair of fixed shafts 12 and 14. On the other fixed shaft 14 side of the output shaft 34, an eccentric shaft 36 is provided in an eccentric state. The eccentric shaft 36 is coupled to the output shaft 34 by a serration coupling portion 38, and has a shaft portion 36A that protrudes on the opposite side of the output shaft 34 in the axial direction. The shaft portion 36 </ b> A is formed coaxially with the output shaft 34.

  The stator 18 is formed in an annular shape and is provided outside the rotor 16 in the radial direction. In the brushless motor having the rotor 16 and the stator 18, when a rotating magnetic field is generated in the stator 18, an attractive / repulsive force acts between the rotor 16 and the stator 18, and the output shaft 34 is rotated together with the rotor 16. The

  The motor housing 20 includes a first housing 40 attached to the stator 18 from one fixed shaft 12 side, and a second housing 42 attached to the stator 18 from the other fixed shaft 14 side. The first housing 40, the stator 18, and the second housing 42 are fixed by bolts 44. Further, the first housing 40 and the stator 18 are fixed by bolts 45.

  The first housing 40 is formed in a flat container shape having a bottom portion on the one fixed shaft 12 side. A disc-like spacer 46 is fixed to the bottom of the first housing 40 with bolts 48. A cylindrical portion 50 is formed at the center of the spacer 46, and one fixed shaft 12 is press-fitted and fixed to the cylindrical portion 50.

  On the other hand, the second housing 42 is formed in a disc shape. The second housing 42 is an example of an opposing wall portion, and is opposed to a carrier body 68 formed on the carrier 24 described later and the output shaft 34 in the axial direction. An accommodation recess 52 is formed in the second housing 42. The housing recess 52 has a concave shape that opens toward the carrier body 68 and is inserted inside the stator 18.

  An annular bearing housing 54 is formed at the center of the bottom of the housing recess 52, and a bearing 56, which is an example of a first bearing, is housed in the bearing housing 54. Similarly, a bearing housing portion 58 is formed at the center of the bottom of the first housing 40 described above, and a bearing 60 that is an example of a first bearing is housed in the bearing housing portion 58. The pair of bearings 56 and 60 rotatably supports both end portions of the output shaft 34 in the axial direction.

  The external gear 22 is rotatably supported on the eccentric shaft 36 via a bearing 62 which is an example of a second bearing. As shown in FIG. 2, a plurality of external teeth 22 </ b> A are formed on the outer peripheral surface of the external gear 22. The external gear 22 has a plurality of conductive holes 64 arranged in the rotational direction. As shown in FIG. 1, the external gear 22 is housed in the housing recess 52 together with the internal gear 28 described later.

  As shown in FIG. 2, the carrier 24 integrally includes a plurality of inner pins 66 inserted into the plurality of conductive holes 64 in an eccentric state and a disc-shaped carrier body 68 that supports the plurality of inner pins 66. Have. The carrier body 68 is formed integrally with the other fixed shaft 14. As shown in FIG. 1, a bearing 70 is provided between the carrier main body 68 and the shaft portion 36A. Further, as shown in FIG. 2, the carrier 24 is formed with a through hole 72 that is coaxial with some of the plurality of inner pins 66 and penetrates in the axial direction of the inner pins 66. Has been.

  On the other hand, a plurality of press-fitting holes 74 into which the respective distal end portions of the plurality of inner pins 66 are press-fitted (light press-fitting) are formed in the second housing 42 facing the carrier body 68. A screw hole 74A (see FIG. 1) is formed in the press-fit hole 74 located coaxially with the through-hole 72 among the plurality of press-fit holes 74. The carrier main body 68 and the second housing 42 are fixed to each other by inserting a bolt 76 through the through hole 72 and screwing the tip of the bolt 76 into the screw hole 74A. The through-hole 72 only needs to be formed in at least one of the plurality of inner pins 66. Further, the screw hole portion 74 </ b> A may be formed in all of the plurality of press-fitting holes 74.

  In addition, as the tip of the bolt 76 is screwed into the screw hole 74A in this way, the tip of each of the plurality of inner pins 66 is press-fitted into the plurality of press-fitting holes 74. The respective distal ends of the inner pins 66 are fixed to the second housing 42.

  The hub 26 includes a substantially cylindrical case 78 and a cover 80 that closes an opening located on the other fixed shaft 14 side among the openings formed in the case 78. The case 78 houses the rotor 16, the stator 18, the motor housing 20, the carrier 24, the external gear 22, the internal gear 28, and the like. In addition, a bearing housing portion 82 is formed in an opening located on the one fixed shaft 12 side among the openings formed in the case 78, and the bearing housing portion 82 is an example of a third bearing. The bearing 84 which is is accommodated. The bearing 84 rotatably supports the case 78 with respect to the above-described spacer 46 fixed to the one fixed shaft 12 so as to be integrally rotatable.

  On the other hand, a bearing housing portion 86 is formed at the center of the cover 80, and a bearing 88 that is an example of a third bearing is housed in the bearing housing portion 86. The bearing 88 rotatably supports the cover 80 with respect to the carrier 24 formed integrally with the other fixed shaft 14. The cover 80 is fixed to the internal gear 28 by a bolt 92 at a fixing portion 90 provided radially outside the internal gear 28. Further, the cover 80 is fixed to the case 78 with bolts 94.

  The internal gear 28 constitutes a speed reduction mechanism together with the external gear 22 and the carrier 24 described above, and has a plurality of internal teeth 28A (see FIG. 3) on the inner peripheral surface. The external gear 22 is in mesh with the internal gear 28.

  In the drive unit 10, when the output shaft 34 is rotated together with the rotor 16, the eccentric shaft 36 is rotated, whereby the meshing position between the internal gear 28 and the external gear 22 is changed. The hub 26 is rotated together with the internal gear 28.

  As shown in FIGS. 1 and 2, in the drive unit 10, one fixed shaft 12, first bearings 56 and 60 (see FIG. 1), rotor 16, stator 18, motor housing 20, and spacer. 46 (see FIG. 1) are assembled together to form a motor assembly 96. Further, the eccentric shaft 36, the bearing 62, the bearing 70, and the external gear 22 are assembled together to constitute a gear assembly 98. Further, as shown in FIGS. 1 and 3, the cover 80, the bearing 88, and the internal gear 28 are assembled together to form the cover assembly 100.

  The drive unit 10 is assembled in the following manner, for example. That is, first, the motor assembly 96, the gear assembly 98, and the cover assembly 100 are each assembled.

  Subsequently, the bolt 76 is inserted into the through-hole 72, and the tip of the bolt 76 is screwed into the screw hole 74A, whereby the carrier body 68 and the second housing 42 are fixed to each other. At this time, the front end portions of the plurality of inner pins 66 are press-fitted into the plurality of press-fitting holes 74 as the front end portions of the bolts 76 are screwed into the screw hole portions 74 </ b> A.

  Further, the bearing 84 is assembled to the bearing housing 82 and the motor assembly 96 is assembled to the case 78 before and after the assembly of the carrier body 68 to the second housing 42. In this state, the cover 80 is fixed to the case 78 with the bolt 94. The drive unit 10 is assembled in the manner described above.

  Next, the operation and effect of one embodiment of the present invention will be described.

  According to the drive unit 10, the pair of fixed shafts 12 and 14 are disposed coaxially with each other, and the output shaft 34 of the rotor 16 is disposed between the pair of fixed shafts 12 and 14. For this reason, the bearing (fourth bearing) which supports the output shaft 34 rotatably with respect to a pair of fixed shafts 12 and 14 becomes unnecessary, and can reduce a number of parts.

  In addition, as described above, by eliminating the need for bearings that rotatably support the output shaft 34 with respect to the pair of fixed shafts 12 and 14, it is possible to avoid a plurality of bearings being arranged concentrically. The drive unit 10 can be reduced in size in the radial direction.

  Furthermore, since the internal gear 28 is connected to the hub 26 (cover 80) so as to be integrally rotatable, the carrier body 68 is provided to be integrally rotatable on the other fixed shaft 14, so that the structure can be simplified. Can do.

  In addition, since both end portions in the axial direction of the inner pin 66 are supported by the carrier body 68 and the second housing 42, the support rigidity of the inner pin 66 can be increased. Thereby, vibration and noise can be suppressed.

  In addition, in this way, when both axial ends of the inner pin 66 are supported by the carrier body 68 and the second housing 42, the durability of the inner pin 66 can be improved.

  Further, as described above, by screwing the bolts 76 into the screw hole portions 74 </ b> A, the respective leading end portions of the plurality of inner pins 66 can be press-fitted into the plurality of press-fit holes 74. Thereby, workability when attaching the carrier 24 to the motor housing 20 (for example, workability when pressurizing each of the plurality of inner pins 66 into the plurality of press-fit holes 74 is eliminated). can do.

  In addition, the respective leading end portions of the plurality of inner pins 66 are press-fitted into the plurality of press-fitting holes 74, whereby the positioning accuracy of the carrier 24 and the motor housing 20 can be improved. Thereby, the coaxial precision of the motor part which has the rotor 16, the stator 18, and the motor housing 20, and the reduction gear mechanism which has the external gear 22, the carrier 24, and the internal gear 28 is securable.

  Furthermore, since the carrier body 68 and the second housing 42 are fixed to each other by the bolt 76 and the screw hole 74A, the mounting rigidity of the carrier 24 to the motor housing 20 can be increased. Thereby, vibration and noise can be further reduced.

  Further, the second housing 42 is formed with a housing recess 52 inserted inside the stator 18, and the internal gear 28 and the external gear 22 are housed in the housing recess 52. Therefore, since the space where the stator 18 is not used can be used effectively, the drive unit 10 can be reduced in the axial direction.

  In addition, a fixing portion 90 that connects the cover 80 and the internal gear 28 is provided on the outer side in the radial direction than the internal gear 28, whereby the force transmitted from the internal gear 28 to the cover 80 (hub 26). A long moment length is secured. Thereby, the structure of the fixing | fixed part 90 can be simplified, for example.

  In addition, since the motor assembly 96, the gear assembly 98, and the cover assembly 100 that are pre-assembled are included, the entire assembly operation can be facilitated.

  Next, a modification of one embodiment of the present invention will be described.

  In the above-described embodiment of the present invention, the drive unit 10 is used as a power source of the electric bicycle, but may be used for other purposes.

  Further, the case 78 is rotatably supported by the spacer 46 via the bearing 84, but may be rotatably supported by the one fixed shaft 12 via the bearing 84.

  Similarly, the cover 80 is rotatably supported by the carrier 24 via the bearing 88, but may be rotatably supported by the other fixed shaft 14 via the bearing 88.

  Although one embodiment of the present invention has been described above, the present invention is not limited to the above, and other various modifications can be made without departing from the spirit of the present invention. It is.

DESCRIPTION OF SYMBOLS 10 ... Drive unit, 12, 14 ... Pair of fixed shaft, 16 ... Rotor, 18 ... Stator, 20 ... Motor housing, 22 ... External gear, 24 ... Carrier , 26 ... hub (rotating member), 28 ... internal gear, 34 ... output shaft, 36 ... eccentric shaft, 36A ... shaft portion, 38 ... serration coupling portion, 40 ... 1st housing, 42 ... 2nd housing (opposite wall part), 46 ... Spacer, 50 ... Cylindrical part, 52 ... Housing recess, 56, 60 ... Bearing (No. One bearing), 60 ... Bearing, 62 ... Bearing (second bearing), 64 ... Conduction hole, 66 ... Inner pin, 68 ... Carrier body, 72 ... Through hole, 74A ... Screw hole, 74 ... Press-fit hole, 76 ... Bolt, 78 ... Case, 80 ... Cover, 8 , 88 ... bearing (third bearing), 90 ... fixed portion, 96 ... motor assembly, 98 ... gear assembly, 100 ... cover assembly

Claims (6)

A pair of fixed shafts arranged coaxially with each other and fixed to the outside;
A rotor having an output shaft disposed coaxially with the pair of fixed shafts between the pair of fixed shafts;
A stator formed in an annular shape and provided radially outside the rotor;
A motor housing fixed to one of the pair of fixed shafts, fixed to the stator, and rotatably supporting the output shaft via a first bearing;
An external gear that is rotatably supported via a second bearing on an eccentric shaft provided in an eccentric state on the output shaft, and in which a plurality of conduction holes are formed side by side in the rotational direction;
A carrier having a plurality of inner pins inserted into the plurality of conduction holes in an eccentric state, and a carrier body that supports the plurality of inner pins and is integrally rotatable on the other of the pair of fixed shafts; ,
A rotating member that is rotatable by a third bearing with respect to the pair of fixed shafts;
The external gear is internally meshed, and the internal gear fixed to the rotating member so as to be integrally rotatable;
Drive unit equipped with. The motor housing has an opposing wall portion facing the carrier body in the axial direction of the output shaft,
Both axial end portions of the plurality of inner pins are fixed to the carrier body and the opposing wall portion,
The drive unit according to claim 1. The carrier is formed with a through-hole penetrating in the axial direction of the inner pin, coaxially with at least one of the plurality of inner pins.
The opposing wall is formed with a plurality of press-fitting holes into which the tip portions of the plurality of inner pins are press-fitted,
A screw hole portion is formed in the press-fitting hole located coaxially with at least the through-hole among the plurality of press-fitting holes,
The carrier body and the opposing wall portion are fixed to each other by inserting a bolt into the through hole and screwing a front end portion of the bolt into the screw hole portion.
The drive unit according to claim 2. The motor housing has an opposing wall portion facing the carrier body in the axial direction of the output shaft,
The opposing wall portion is formed with an accommodation recess that is inserted inside the stator and opens to the carrier body side,
In the housing recess, the internal gear and the external gear are housed.
The drive unit as described in any one of Claims 1-3. The fixing portion that fixes the rotating member and the internal gear is provided on a radially outer side than the internal gear.
The drive unit as described in any one of Claims 1-4. The rotating member is
A case that houses the rotor, the stator, the motor housing, the carrier, the external gear, and the internal gear, and that has an opening on the other side of the pair of fixed shafts;
A cover for closing the opening;
Have
The carrier is formed integrally with the other of the pair of fixed shafts;
One of the pair of fixed shafts, the first bearing, the rotor, the stator, and the motor housing are assembled together to form a motor assembly,
The eccentric shaft, the second bearing, and the external gear are assembled together to form a gear assembly,
The cover, the third bearing, and the internal gear are assembled together to form a cover assembly.
The drive unit as described in any one of Claims 1-5.