Drive unit and assembly method of drive unit

Abstract

To provide a drive unit and an assembly method of the drive unit which can improve location accuracy of an electric motor with respect to a housing.SOLUTION: A drive unit 1 comprises: a housing 4; and an electric motor 2 comprising a motor case 6 accommodated in the housing 4. The motor case 6 comprises: a cylinder part 13; and a flange part 12 radially projecting from an opening end of the cylinder part 13. The housing 4 comprises: a plurality of positioning projections 43, 44 with which the flange part 12 is brought into contact; and female screw parts 45 for fixing the flange part 12.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a drive unit and a method for assembling a drive unit. [Background technology]

[0002] Among the drive devices that generate driving force for operating various mechanical devices, there are some that include an electric motor. In many cases, the electric motor is fixed to the corresponding mechanical device via a housing (casing). For example, the electric motor is fastened to the housing by bolts. The housing is also provided with a plurality of gears, and the rotation of the electric motor is transmitted to the mechanical device via the gears, so that the driving force for operating the mechanical device is generated by the driving device. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6812458 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-mentioned drive device, when trying to improve the efficiency of power transmission from the electric motor to the mechanical device, the positional accuracy of the gears and the electric motor is important because it is necessary to take into account the meshing resistance of the gears, etc. However, simply fixing the electric motor to the housing poses the problem that it is difficult to improve the positional accuracy of the electric motor relative to the housing because the cumulative tolerances of the housing and the electric motor have a large effect.

[0005] Therefore, the present invention provides a drive device and a method for assembling the drive device that can improve the positional accuracy of the electric motor with respect to the housing. [Means for solving the problem]

[0006] In order to solve the above problems, in a first aspect of the present invention, a drive device comprises a housing and an electric motor having a motor case accommodated in the housing, the motor case having a cylindrical portion and a flange portion extending radially from an open end of the cylindrical portion, and the housing has a plurality of positioning protrusions against which the flange portion abuts and a fixing portion for fixing the flange portion.

[0007] With this configuration, the contact area between the housing and the electric motor (motor case) can be reduced as much as possible. This makes it possible to minimize the effect of cumulative tolerances between the housing and the electric motor on the positional accuracy of the electric motor relative to the housing. In addition, because the contact area of ​​the electric motor with the housing can be reduced, the accuracy of this contact area (flatness, etc.) can be easily improved. This makes it possible to improve the positional accuracy of the electric motor with respect to the housing.

[0008] In a second aspect of the present invention, in the drive device of the first aspect, the fixing portion may be formed on a contact surface of the positioning protrusion with the flange portion.

[0009] With this configuration, the contact area between the housing and the electric motor can be further reduced. Moreover, the electric motor can be easily fixed to the housing while the flange portion is abutting against the positioning protrusion. This makes it easy to improve the positioning accuracy of the electric motor relative to the housing.

[0010] In a third aspect of the present invention, in the drive mechanism of the first or second aspect, a fastener fixed to the fixed portion may be provided, and the flange portion may have a fastener insertion hole through which the fastener is inserted.

[0011] With this configuration, the electric motor can be easily positioned in the radial direction relative to the housing by utilizing the fastener and the fastener insertion hole.

[0012] In a fourth aspect of the present invention, in the drive device of any one of the first to third aspects, the housing may have a storage recess for storing the motor case, and the motor case may be fitted into the storage recess with the radial gap formed between the motor case and the storage recess.

[0013] With this configuration, the position of the electric motor can be finely adjusted while the electric motor is housed in the housing, which makes it easier to position the electric motor relative to the housing.

[0014] In a fifth aspect of the present invention, in the drive device of the third aspect, the motor case is formed by pressing a metal plate, the fastener insertion hole is formed by punching out the flange portion by the press processing, and burrs generated on the periphery of the fastener insertion hole may protrude on the opposite side to the positioning protrusion.

[0015] With this configuration, the flange portion can be brought into close contact with the positioning protrusion, thereby further improving the positioning accuracy of the electric motor with respect to the housing.

[0016] In a sixth aspect of the present invention, a method for assembling a drive unit includes a housing having a storage recess, and an electric motor having a motor case stored in the storage recess, the motor case having a cylindrical portion and a flange portion extending radially from an opening end of the cylindrical portion, and the housing having a plurality of positioning protrusions against which the flange portion abuts, and a fixing portion for fixing the flange portion, the method including a storage step of gripping a motor shaft of the electric motor using a jig and storing the electric motor in the storage recess, a flange portion pressing step of, after the storage step, pressing from above around the periphery of a portion of the flange portion corresponding to the positioning protrusion and pressing the flange portion against the positioning protrusion, and a fixing step of, after the flange portion pressing step, fixing the flange portion using the fixing portion.

[0017] By using this method, the contact area between the housing and the electric motor (motor case) can be reduced as much as possible, and fine adjustment of the electric motor can be easily performed when assembling the electric motor to the housing, thereby improving the positional accuracy of the electric motor relative to the housing.

[0018] In a seventh aspect of the present invention, in the method of assembling the drive device of the sixth aspect, a fixing device is fixed to the fixed portion, the flange portion has a fixing device insertion hole through which the fixing device is inserted, and the motor case is formed by pressing a metal plate, and the punching direction when forming the fixing device insertion hole may be a direction from the abutment surface side with the positioning protrusion to the opposite side of the abutment surface with the positioning protrusion.

[0019] By using this method, the flange portion can be tightly attached to the positioning protrusion, which further improves the positioning accuracy of the electric motor with respect to the housing. Effect of the Invention

[0020] According to the present invention, the positional accuracy of the electric motor with respect to the housing can be improved. [Brief description of the drawings]

[0021] [Figure 1] FIG. 2 is a cross-sectional view of a drive device according to an embodiment of the present invention. [Diagram 2] FIG. 2 is an exploded perspective view of a drive device according to the embodiment of the present invention. [Diagram 3] 5A and 5B are explanatory diagrams illustrating a shape of a part of a flange portion in the embodiment of the present invention. [Figure 4] 1 is a plan view of a drive device according to an embodiment of the present invention, viewed from above. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Next, an embodiment of the present invention will be described with reference to the drawings.

[0023] <Drive unit> Fig. 1 is a cross-sectional view of the drive device 1. Fig. 2 is an exploded perspective view of the drive device 1. The drive unit 1 is a device that serves as a power source for starting an engine (prime mover) of, for example, a two-wheeled vehicle or a four-wheeled vehicle. The drive unit 1 is provided, for example, in a power unit (not shown). The power unit is an integrated unit of an engine and a transmission (not shown). For example, the power unit of a two-wheeled vehicle is connected to the rear wheel via a chain-type transmission mechanism.

[0024] As shown in Figs. 1 and 2, the drive device 1 includes two electric motors 2, a holder 3 that integrally holds the two electric motors 2, and a housing 4 that houses the two electric motors 2. The two electric motors 2 are arranged side by side. The two electric motors 2 are arranged symmetrically with the electric motors 2 at the center. The two electric motors 2 have the same configuration. Therefore, in the following description, only one of the two electric motors 2 will be described, and the description of the other will be omitted. The two electric motors 2 are given the same reference numerals.

[0025] <Electric motor> The electric motor 2 is a so-called brushed motor. The electric motor 2 includes an armature 5 and a motor case 6 in which the armature 5 is rotatably housed. The armature 5 includes a motor shaft 7, an armature core 8 fitted and fixed to the motor shaft 7, and a commutator 9 fitted and fixed to the motor shaft 7. In the following description, the axial direction of the motor shaft 7 will be simply referred to as the axial direction. The radial direction of the motor shaft 7 will be simply referred to as the radial direction. The rotation direction of the armature 5, that is, the direction around the motor shaft 7 will be simply referred to as the circumferential direction.

[0026] A coil (not shown) is wound around the armature core 8. An end portion of the coil is connected to the commutator 9. The commutator 9 has a plurality of conductive commutator pieces 9a. The commutator pieces 9a are arranged at predetermined intervals in the circumferential direction. The commutator 9 and the armature core 8 are arranged side by side in the axial direction. Hereinafter, in the axial direction, the armature core 8 side may be referred to as the lower side, and the commutator 9 side may be referred to as the upper side.

[0027] The motor case 6 has a cylindrical yoke portion 11 with a bottom, and a flange portion 12 integrated with the yoke portion 11. The yoke portion 11 has a cylindrical portion 13 centered in the axial direction, and a bottom portion 14 formed at the lower end of the cylindrical portion 13. A permanent magnet 23 is provided on the inner peripheral surface of the cylindrical portion 13. The permanent magnet 23 faces the armature core 8 in the radial direction. A bearing boss 14a that protrudes downward is formed on the bottom portion 14. A bearing 15 is provided on the bearing boss 14a. The bearing 15 supports the lower end portion 7a of the motor shaft 7 so as to be rotatable.

[0028] The flange portion 12 is formed by pressing a metal plate so as to close the opening 13a of the tube portion 13. The flange portion 12 is formed so as to protrude radially from the opening 13a of the tube portion 13. The flange portion 12 is formed in a pentagonal shape when viewed from the axial direction. That is, when viewed from the axial direction, the flange portion 12 has a bottom portion 12a, two side portions 12b extending from both ends of the bottom portion 12a in a direction perpendicular to the bottom portion 12a, and two oblique portions 12c extending obliquely from the end of the side portion 12b opposite the bottom portion 12a. The ends of the two oblique portions 12c opposite the side portion 12b are connected to each other. Therefore, two bottom corners 12d are formed between the bottom portion 12a and the side portion 12b. Two oblique corners 12e are formed between the side portion 12b and the oblique portion 12c. A vertex 12f is formed at the point where the two oblique portions 12c are connected.

[0029] Fig. 3 is an explanatory diagram for explaining the shape of a part of the flange portion 12. In Fig. 3, the scale has been appropriately changed for ease of understanding. 1 to 3, a bottom bolt insertion hole 18a is formed in each of two bottom corners 12d of the flange portion 12. A vertex bolt insertion hole 18b is formed in the vertex portion 12f of the flange portion 12.

[0030] The bolt insertion holes 18a, 18b are formed in the same shape by the same processing. The bolt insertion holes 18a, 18b are formed by punching the flange portion 12. The punching direction D is a direction from the lower surface 12g of the flange portion 12 on the yoke portion 11 side toward the upper surface 12h of the flange portion 12 opposite the lower surface 12g. Therefore, burrs 24 generated on the periphery of the bolt insertion holes 18a, 18b when forming the bolt insertion holes 18a, 18b protrude from the upper surface 12h toward the opposite side to the yoke portion 11 (upward). The bolts 10 for fixing the flange portion 12 (motor case 6) to the housing 4 are inserted into the bolt insertion holes 18a, 18b.

[0031] A bearing boss 16 that protrudes axially outward is provided at the center of the flange portion 12 when viewed from the axial direction. A through hole 16b is formed in a bottom portion 16a of the bearing boss 16. The upper end portion 7b of the motor shaft 7 is inserted into the through hole 16b. The bearing boss 16 is provided with a bearing 17. The bearing 17 rotatably supports the motor shaft 7 near the upper end portion 7b. The upper end portion 7b of the motor shaft 7 protrudes upward through the through hole 16b of the bearing boss 16. A pinion gear 19 is fitted and fixed into this protruding portion.

[0032] A brush holder 20 is provided on a lower surface 12g of the flange portion 12 on the yoke portion 11 side. The brush holder 20 holds a brush (not shown) that is in sliding contact with the commutator piece 9a. The brush holder 20 is integrally formed with two terminal holding portions 21a, 21b (a first terminal holding portion 21a and a second terminal holding portion 21b) that protrude from an upper surface 12h opposite to the lower surface 12g of the flange portion 12. The two terminal holding portions 21a, 21b are disposed opposite each other on both sides of the fitting cylindrical portion 32 of the flange portion 12.

[0033] More specifically, of the two terminal holding portions 21a, 21b, the first terminal holding portion 21a is disposed between the two bottom side bolt insertion holes 18a. The distance of the first terminal holding portion 21a from the bottom side portion 12a is longer than the distance of the bottom side bolt insertion hole 18a from the bottom side portion 12a. That is, the first terminal holding portion 21a is disposed closer to the bearing boss 16 than the bottom side bolt insertion hole 18a. Of the two terminal holding portions 21a, 21b, the second terminal holding portion 21b is disposed between the apex side bolt insertion hole 18b and the bearing boss 16.

[0034] A terminal 22 is inserted into each of the terminal holding portions 21a and 21b. A brush (not shown) is connected to the lower end of the terminal 22. A harness extending from an external power source (not shown) is connected to the upper end of the terminal 22. With this configuration, power from an external power source is supplied to the brushes via the terminals 22. The power supplied to the brushes is further supplied to a coil (not shown) via the commutator 9. This generates a predetermined magnetic field in the armature core 8, which generates magnetic attraction and repulsion between the armature core 8 and the permanent magnet 23 of the yoke portion 11. This causes the armature 5 to rotate continuously.

[0035] The two electric motors 2 are arranged symmetrically with respect to the space between the electric motors 2, and the motor shafts 7 are parallel to each other. The bottom sides 12a of the flanges 12 of the two electric motors 2 face each other. For example, a spur gear of a power unit (not shown) is arranged between the pinion gears 19 of the two electric motors 2. The pinion gears 19 mesh with each other, and the power of the drive device 1 is transmitted to the power unit.

[0036] <Holder> FIG. 4 is a plan view of the drive device 1 as viewed from above. 1, 2 and 4, the holder 3 is made of resin. The holder 3 has a plate-shaped base portion 31 and two fitting cylindrical portions 32 integrally molded with the base portion 31. The bearing bosses 16 of the electric motors 2 are fitted into the two fitting cylindrical portions 32, respectively. In other words, the holder 3 serves to temporarily position each electric motor 2.

[0037] The base portion 31 is formed across the two fitting cylindrical portions 32 so as to integrate the two fitting cylindrical portions 32. More specifically, the base portion 31 is formed in a rectangular shape that is long in the arrangement direction of the two electric motors 2 (left-right direction in Figs. 1, 2, and 4) as viewed from the axial direction. Hereinafter, the longitudinal direction of the base portion 31 as viewed from the axial direction will be referred to as the X-direction. The lateral direction of the base portion 31 will be referred to as the Y-direction.

[0038] The base portion 31 extends between the second terminal holding portions 21b of the two electric motors 2. That is, the periphery of the apex-side bolt insertion hole 18b of the flange portion 12 of the motor case 6 is located outside both sides of the holder 3 in the X direction. Therefore, when the holder 3 is viewed from above, the area from the oblique-side corner portion 12e to the apex portion 12f of the flange portion 12 is exposed.

[0039] The base portion 31 has terminal through holes 33 through which the first terminal holding portions 21a are inserted when the two electric motors 2 are assembled. The first terminal holding portions 21a protrude upward through the terminal through holes 33. Terminal recesses 34 are formed on both sides in the X direction of the base portion 31 at locations corresponding to the second terminal holding portions 21b when the two electric motors 2 are assembled. The second terminal holding portions 21b protrude upward through the terminal recesses 34.

[0040] A bolt insertion opening 35 is formed in one of the Y-direction sides of the base portion 31 (the upper side in FIG. 4) at a location corresponding to the bottom bolt insertion hole 18a when the two electric motors 2 are assembled. Jig insertion openings 36 are formed in the base portion 31 on both sides outside the bolt insertion opening 35 in the X-direction.

[0041] An assembly recess 37 is formed on the other of the two Y-direction sides of the base portion 31 (lower side in FIG. 4) at a location corresponding to the bottom side bolt insertion hole 18a and its surroundings when the two electric motors 2 are assembled. The assembly recess 37 has a bolt insertion recess 37a formed at a location corresponding to the bottom side bolt insertion hole 18a, and a jig insertion recess 37b formed on both sides outside the bolt insertion recess 37a in the X-direction. The bolt insertion recess 37a and the jig insertion recess 37b are in communication. The depth of the bolt insertion recess 37a in the Y-direction is deeper than the depth of the jig insertion recess 37b in the Y-direction.

[0042] In this way, when the holder 3 is viewed from above, the bolt insertion opening 35, the jig insertion opening 36, and the assembly recess 37 expose the bottom bolt insertion hole 18a and the area closer to the apex 12f in the X direction than the bottom bolt insertion hole 18a. In addition, a plurality of harness holding claws 38 are formed on the upper surface 31a of the base portion 31 opposite the electric motor 2. The harness holding claws 38 hold a harness (not shown) connected to the terminals 22 of the electric motor 2. Furthermore, a plurality of motor engagement claws 39 (four in this embodiment) that protrude downward are formed on both sides of the base portion 31 in the Y direction. The motor engagement claws 39 engage the holder 3 with the flange portion 12 of the electric motor 2.

[0043] <Housing> The housing 4 has a block body 40 in which two storage recesses 41 are formed in which the electric motor 2 is stored. The storage recess 41 has a storage opening 41a at its upper part. When viewed from the axial direction, it is formed in a circular shape corresponding to the cylindrical portion 13 constituting the yoke portion 11 of the electric motor 2. The inner peripheral surface of the storage recess 41 is formed in a slight taper so that the inner diameter gradually increases from the storage bottom portion 41b toward the storage opening 41a, that is, so that it flares out toward the end. The entire yoke portion 11 is stored in such a storage recess 41.

[0044] The inner diameter of the storage recess 41 on the storage bottom 41b side is slightly larger than the outer diameter of the tubular portion 13 of the yoke portion 11. A bearing storage recess 47 in which the bearing boss 14a of the yoke portion 11 is stored is formed in the storage bottom 41b. The bearing storage recess 47 is also formed in a circular shape when viewed from the axial direction so as to correspond to the bearing boss 14a. The inner diameter of the bearing storage recess 47 is slightly larger than the outer diameter of the bearing boss 14a. Therefore, the electric motor 2 is fitted into the storage recess 41 with a radial gap formed. Therefore, the electric motor 2 can move slightly in the XY directions while stored in the storage recess 41.

[0045] A cylindrical portion 42 is formed on an upper surface 40a of the block body 40 on the storage opening 41a side so as to extend from the side surface of the block body 40. A cylindrical portion opening 42a is formed on the side of the cylindrical portion 42 opposite the block body 40. The upper surface 40a of the block body 40 and the inner surface 42b of the tube portion 42 are formed with a plurality of (six in this embodiment) positioning protrusions 43, 44 (bottom side positioning protrusion 43, apex side positioning protrusion 44) so ​​as to be joined to the upper surface 40a and the inner surface 42b.

[0046] Of the positioning protrusions 43, 44, the bottom side positioning protrusion 43 is formed at a location corresponding to the bottom side bolt insertion hole 18a of the flange portion 12. Each bottom side positioning protrusion 43 is formed in a circular shape when viewed in the axial direction. However, the bottom side positioning protrusions 43 adjacent to each other in the X direction are integrated with each other. Therefore, the two bottom side positioning protrusions 43 form an oval shape when viewed in the axial direction.

[0047] Of the positioning protrusions 43, 44, the apex side positioning protrusion 44 is formed at a location corresponding to the apex side bolt insertion hole 18b of the flange portion 12. Each apex side positioning protrusion 44 is formed in a circular shape when viewed from the axial direction. The upper surfaces 43a, 44a of each positioning protrusion 43, 44 are formed flat along the XY direction.

[0048] The periphery of the bottom side bolt insertion hole 18a of the flange portion 12 is placed on the upper surface 43a of the bottom side positioning protrusion 43. The periphery of the apex side bolt insertion hole 18b of the flange portion 12 is placed on the upper surface 44a of the apex side positioning protrusion 44. In this manner, each of the upper surfaces 43a, 44a serves as a contact surface with the flange portion 12. The lower surface 12g of the flange portion 12 is in contact with only each of the upper surfaces 43a, 44a of the housing 4. That is, the flange portion 12 of each electric motor 2 is in contact with only the corresponding three positioning protrusions 43, 44.

[0049] A female screw portion 45 into which the bolt 10 is screwed is formed on each of the upper surfaces 43a, 44a. The bolt 10 is screwed into each female screw portion 45 through each bolt insertion hole 18a, 18b after the flange portion 12 is placed on the upper surfaces 43a, 44a of the positioning protrusions 43, 44. This fastens and fixes each flange portion 12 (electric motor 2) to the housing 4. That is, the female screw portion 45 functions as a fixing portion for fixing the flange portion 12 to the housing 4. A method for assembling the drive unit 1 will be described in detail later.

[0050] <How to assemble the drive unit> Next, a method for assembling the drive unit 1 will be described. First, the electric motor 2 is assembled, and then the bearing boss 16 of the electric motor 2 is fitted into the fitting cylindrical portion 32 of the holder 3. Then, the motor engagement claw 39 of the holder 3 is engaged with the flange portion 12. As a result, the holder 3 and the two electric motors 2 are provisionally fixed and integrated.

[0051] Next, the portion of the motor shaft 7 of each electric motor 2 that is exposed to the outside between the bearing boss 16 and the pinion gear 19 is gripped by a tool (not shown). Then, the bottom 14 of the yoke portion 11 is faced to the storage opening 41a of the housing 4, and the electric motor 2 is stored in the storage recess 41 as it is (storing process). Then, the flange portion 12 is placed on the upper surfaces 43a, 44a of the positioning protrusions 43, 44. Here, burrs 24 that are generated around the periphery of the bolt insertion holes 18a, 18b when forming the bolt insertion holes 18a, 18b protrude from the upper surface 12h of the flange portion 12 toward the opposite side (upward) from the yoke portion 11. Therefore, the flange portion 12 is tightly attached to the upper surfaces 43a, 44a of the positioning protrusions 43, 44.

[0052] In the storage step, the motor shaft 7 is held as is by a tool (not shown), so that the dimension between the motor shafts 7 of the two electric motors 2 is determined with high precision regardless of the manufacturing error of each electric motor 2. Moreover, the electric motor 2 is fitted into the storage recess 41 with a radial gap formed. Therefore, the electric motor 2 can move slightly in the XY directions while stored in the storage recess 41. Therefore, the electric motor 2 can move slightly in the X direction. This makes it possible for the storage recess 41 to absorb manufacturing errors of the electric motor 2 and the housing 4. As a result, the electric motors 2 are stored in the storage recesses 41 while the dimension between the motor shafts 7 of the two electric motors 2 is maintained with high precision.

[0053] Next, the periphery of the portions of the flange portion 12 corresponding to the positioning protrusions 43, 44 is pressed from above by a pressing tool 50 (see FIG. 4). Then, the flange portion 12 is pressed against the positioning protrusions 43, 44 (pressing step). The periphery of the portion of the flange portion 12 corresponding to the positioning protrusions 43, 44 is the exposed portion of the flange portion 12 when the holder 3 is viewed from above.

[0054] Specifically, the pressing tool 50 is inserted into the jig insertion opening 36 of the holder 3, and the pressing tool 50 is inserted into the jig insertion recess 37b to press the flange portion 12. As a result, the bottom corner portion 12d of the flange portion 12 is pressed against the bottom positioning protrusion 43. Furthermore, both sides of the apex portion 12f of the flange portion 12 in the Y direction are pressed across the apex side bolt insertion hole 18b by the pressing tool 50. As a result, the apex portion 12f of the flange portion 12 is pressed against the apex side positioning protrusion 44.

[0055] After the pressing step, the female threads 45 of the positioning protrusions 43, 44 and the bolt insertion holes 18a, 18b are approximately coaxial with each other. Next, with the flange portion 12 pressed against the positioning protrusions 43, 44, the bolts 10 are screwed into the female threads 45 from above the flange portion 12 through the bolt insertion holes 18a, 18b. This fastens and fixes the flange portions 12 (electric motor 2) to the housing 4 (fixing process). Then, the assembly of the drive unit 1 is completed.

[0056] Thus, in the above-mentioned drive device 1, the electric motor 2 has a flange portion 12 that protrudes radially from the cylindrical portion 13. The housing 4 has a plurality of positioning protrusions 43, 44 against which the flange portion 12 abuts, and a female screw portion 45 as a fixing portion. Therefore, the contact area between the housing 4 and the flange portion 12 (electric motor 2) can be reduced as much as possible. As a result, the influence of accumulated errors between the housing 4 and the electric motor 2 on the position accuracy of the electric motor 2 relative to the housing 4 can be reduced as much as possible. In addition, since the contact area of ​​the electric motor 2 with the housing 4 can be reduced, the accuracy (flatness, etc.) of this contact area can be easily improved. In other words, it is only necessary to process, for example, the flatness of the upper surfaces 43a, 44a of the positioning protrusions 43, 44 with high accuracy. Therefore, the position accuracy of the electric motor 2 with respect to the housing 4 can be easily and reliably improved. In addition, for example, the drive device 1 can be properly meshed with a spur gear of a power unit (not shown), and the efficiency of drive transmission from the drive device 1 to the power unit can be improved.

[0057] The female screw portion 45 as a fixing portion is not formed with a fixing seat surface separate from each of the positioning protrusions 43, 44. By forming the female screw portion 45 on each of the positioning protrusions 43, 44, the positioning protrusions 43, 44 also serve as the fixing portion. This reliably reduces the contact area between the housing 4 and the flange portion 12. Moreover, it is possible to easily fix the electric motor 2 to the housing 4 while abutting the flange portion 12 against each of the positioning protrusions 43, 44. This makes it possible to easily improve the positional accuracy of the electric motor 2 relative to the housing 4.

[0058] The electric motor 2 is fixed to the housing 4 using bolts 10. A bottom bolt insertion hole 18a and a top bolt insertion hole 18b for inserting the bolts 10 are formed in the flange portion 12 of the electric motor 2. Therefore, by inserting the bolts 10 into the bolt insertion holes 18a, 18b and screwing the bolts 10 into the female threaded portion 45, it is possible to easily determine the radial positioning of the electric motor 2 relative to the housing 4 to a certain extent. This makes it possible to easily improve the positional accuracy of the electric motor 2 relative to the housing 4.

[0059] The electric motor 2 is fitted into the storage recess 41 with a radial gap formed therein. Therefore, the electric motor 2 can move slightly in the XY directions while stored in the storage recess 41. That is, the position of the electric motor 2 can be finely adjusted while stored in the housing 4. This makes it easier to position the electric motor 2 relative to the housing 4.

[0060] The bolt insertion holes 18a, 18b formed in the flange portion 12 are formed by punching the flange portion 12 by press working. The punching direction D is a direction from the lower surface 12g of the flange portion 12 on the yoke portion 11 side toward the upper surface 12h of the flange portion 12 opposite the lower surface 12g. Therefore, the burrs 24 generated on the periphery of the bolt insertion holes 18a, 18b when forming the bolt insertion holes 18a, 18b protrude from the upper surface 12h toward the opposite side (upward) from the yoke portion 11. As a result, when the flange portion 12 is placed on the upper surfaces 43a, 44a of the positioning protrusions 43, 44, the flange portion 12 can be in close contact with the upper surfaces 43a, 44a of the positioning protrusions 43, 44. Therefore, the positional accuracy of the electric motor 2 with respect to the housing 4 can be further improved.

[0061] The method for assembling the drive unit 1 includes a storage step of storing the electric motor 2 in the storage recess 41, a flange portion pressing step of pressing the flange portion 12 against each of the positioning protrusions 43, 44 after the storage step, and a fixing step of fixing the flange portion 12 to the housing 4 with the bolts 10 after the flange portion pressing step. This makes it easy to fine-tune the electric motor 2 when assembling it to the housing 4 while minimizing the contact area between the housing 4 and the electric motor 2 (motor case 6). This improves the positional accuracy of the electric motor 2 relative to the housing 4.

[0062] This can improve the positioning accuracy of the electric motor 2 relative to the housing 4 and, for example, can also improve the efficiency of power transmission from the drive unit 1 to the power unit, making it possible to contribute to Goal 7 of the Sustainable Development Goals (SDGs) led by the United Nations, "Ensure access to affordable, reliable, sustainable and modern energy for all," Goal 9, "Build resilient infrastructure, promote inclusive and sustainable industrialization and foster innovation," and Goal 12, "Ensure sustainable consumption and production patterns."

[0063] The present invention is not limited to the above-described embodiment, and includes various modifications to the above-described embodiment without departing from the spirit of the present invention. For example, in the above embodiment, the electric motor 2 is a so-called brushed motor, but is not limited to this and may be a so-called brushless motor.

[0064] In the above embodiment, the flange portion 12 of the electric motor 2 is formed in a pentagonal shape when viewed in the axial direction. The housing 4 is in contact with one flange portion 12 and three positioning protrusions 43, 44. However, this is not limited to this, and the shape of the flange portion 12 can be determined arbitrarily. The number of positioning protrusions may be more than one.

[0065] In the above embodiment, the female screw portion 45 is formed as a fixing portion in each of the positioning protrusions 43, 44. However, this is not limited to this, and for example, a fixing seat may be provided separately from each of the positioning protrusions 43, 44, and the female screw portion 45 may be formed on this fixing seat.

[0066] In the above embodiment, a description has been given of a case in which the female thread portion 45 is used as a fixing portion and the bolt 10 is used as a fastener fixed to the female thread portion 45 as a means for fastening the flange portion 12 to the housing 4. However, this is not limited to this, and various fixing portions and fasteners can be applied. For example, a fixing pin may be used as the fastener instead of the bolt 10. In this case, a fixing hole into which the fixing pin is press-fitted may be used as the fixing portion instead of the female thread portion 45.

[0067] In the above embodiment, the drive device 1 is described as having two electric motors 2. However, this is not limited to this, and the number of electric motors 2 may be one, or three or more. Even in these cases, the positional accuracy of the electric motor 2 with respect to the housing 4 can be improved by the above-mentioned configuration. [Explanation of symbols]

[0068] 1...drive device, 2...electric motor, 3...holder, 4...housing, 5...armature, 6...motor case, 7...motor shaft, 7a...lower end, 7b...upper end, 8...armature core, 9...commutator, 9a...commutator piece, 10...bolt, 11...yoke portion, 12...flange portion, 12a...bottom portion, 12b...side portion, 12c...hypothetical portion, 12d...bottom side corner portion, 12e...hypothetic side corner portion, 12f...apex portion, 12g...lower surface, 12h...upper surface, 13...tubular portion, 13a...opening portion, 14...bottom portion, 14a...bearing boss, 15...bearing, 16...bearing boss, 16a...bottom portion, 16b...through hole, 17...bearing, 18a...bottom bolt insertion hole, 18b...apex bolt insertion hole, 19...pinion gear, 20...brush holder, 21a...first 1 terminal holding portion, 21b...second terminal holding portion, 22...terminal, 23...permanent magnet, 24...burr, 31...base portion, 31a...upper surface, 32...fitting cylindrical portion, 33...terminal through hole, 34...terminal recess, 35...bolt insertion opening, 36...jig insertion opening, 37...assembly recess, 37a...bolt insertion recess, 37b...jig insertion recess, 38...harness holding claw, 39...motor engagement claw, 40...block body, 40a...upper surface, 41...storage recess, 41a...storage opening, 41b...storage bottom, 42...tubular portion, 42a...tubular portion opening, 42b...inner surface, 43...positioning protrusion, 43a...upper surface, 44...positioning protrusion, 44a...upper surface, 45...female thread portion, 47...bearing storage recess, 50...pressing tool, D...punching direction, X...longitudinal direction, Y...transverse direction

Claims

1. Housing and an electric motor having a motor case accommodated in the housing; Equipped with The motor case includes: A cylindrical portion and a flange portion extending radially from an open end of the cylindrical portion; having The housing includes: A plurality of positioning protrusions to which the flange portion is abutted; A fixing portion for fixing the flange portion; having A drive device characterized by:

2. The fixing portion is formed on a contact surface of the positioning protrusion with the flange portion.

2. The drive device according to claim 1 .

3. A fixture is provided to be fixed to the fixed portion, The flange portion has a fastener insertion hole through which the fastener is inserted.

3. The drive device according to claim 1 or 2.

4. the housing has a storage recess for storing the motor case, the motor case is fitted into the storage recess with a gap formed between the motor case and the storage recess in the radial direction; 3. The drive device according to claim 1 or 2.

5. The motor case is formed by pressing a metal plate, the fastener insertion hole is formed by punching out the flange portion by the press working, The burrs generated on the periphery of the fastener insertion hole protrude on the opposite side to the positioning protrusion.

4. The drive device according to claim 3.

6. a housing having a storage recess; an electric motor having a motor case that is accommodated in the accommodation recess; Equipped with The motor case includes: A cylindrical portion and a flange portion extending radially from an open end of the cylindrical portion; having The housing includes: A plurality of positioning protrusions to which the flange portion is abutted; A fixing portion for fixing the flange portion; A method for assembling a drive device, comprising: a housing step of gripping a motor shaft of the electric motor using a jig and housing the electric motor in the housing recess; a flange portion pressing step of pressing a periphery of a portion of the flange portion corresponding to the positioning protrusion from above after the storing step, and pressing the flange portion against the positioning protrusion; a fixing step of fixing the flange portion using the fixing portion after the flange portion pressing step; Equipped with A method for assembling a drive device comprising the steps of:

7. A fixture is provided to be fixed to the fixed portion, The flange portion has a fastener insertion hole through which the fastener is inserted, The motor case is formed by pressing a metal plate, a punching direction when forming the fastener insertion hole is a direction from the contact surface side with the positioning protrusion toward the opposite side to the contact surface with the positioning protrusion; 7. The method for assembling a drive device according to claim 6.

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