JP2012228966A - In-wheel motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an in-wheel motor in which the coaxial accuracy of a pair of fixed axes projected from both right and left sides of a hub is improved to suppress vibration, abnormal sounds, and noise from being generated, thereby contributing to improvement in ride quality.SOLUTION: The in-wheel motor 10 includes: the hub 12; a first fixed axis member 20 penetrating one surface side of the hub 12 and rotatably supporting the hub 12; a second fixed axis member 24 penetrating the other surface side of the hub 12 coaxially with the first fixed axis member 20 and rotatably supporting the hub 12; a motor 26 disposed in the hub 12; a reduction mechanism 28 having a through hole 66a coaxially with the second fixed axis member 24 and reducing the rotation speed of a rotor core 52; an internal gear 46 which is fixed to an inner periphery of the hub 12, and to which an output gear of the reduction mechanism 28 is connected; and a third fixed axis member 40 for coupling the first fixed axis member 20 with the second fixed axis member 24 via the through hole 66a on axis lines thereof.

Description

  The present invention relates to a technique for improving vibration characteristics and noise characteristics of an in-wheel motor, particularly an in-wheel motor.

  Conventionally, an in-wheel motor has been used as one of driving sources for running a vehicle. For example, there are an electric motorcycle, an electric wheelchair, a motorized scooter, an electric cart, a golf cart, an electric bicycle, and the like. An in-wheel motor is, for example, as described in Patent Document 1, a ring-shaped internal gear in which a rotor of a motor housed in a wheel hub is fixed to an inner wall surface of a hub via a gear train. The rotor is connected and transmits the rotational force of the rotor to the hub.

Japanese Patent No. 3803252

  As shown in Patent Document 1 described above, when an in-wheel motor is used in an electric motorcycle or the like, the in-wheel motor is a fork that is a pair of fixed shafts that protrude from the left and right sides of the hub and that is a part of the vehicle frame. Supporting structures are common. At this time, the pair of fixed shafts protruding left and right from the hub needs to have high coaxial accuracy. If the coaxial accuracy is low, the hub, that is, the center of rotation of the in-wheel motor is inclined and fixed with respect to the support center of the fork of the vehicle. As a result, the vehicle is caused to vibrate up and down and left and right when the wheels rotate, and it may cause abnormal noise and noise due to the vibration. The occurrence of vibration, abnormal noise, noise, and the like also causes a decrease in riding comfort.

  In the case of the structure of Patent Document 1, the fixed shaft protruding from the left and right sides of the hub is supported by a bearing provided on the hub that houses a rotor, a stator, a speed reducer, and the like. In this case, the force applied to the fixed shaft protruding from the left and right of the hub, for example, the force due to the weight of the vehicle or the weight of the passenger or the load is applied to each fixed shaft. Since the fixed shafts protruding from the left and right are individually supported by the hub via bearings, when a force is applied, the fixed shaft protruding to the left side tilts to the left and the fixed shaft protruding to the right side tilts to the right. That is, there is a problem that it is difficult to maintain the coaxial accuracy of the left and right fixed shafts. Further, the bearing has a backlash between the inner ring and the outer ring, and this backlash has caused a decrease in the coaxial accuracy of the left and right fixed shafts. In the case of the structure of Patent Document 1, the left and right fixed shafts are indirectly connected via the rotor. However, since it is necessary to rotate the rotor with respect to the fixed shaft, it is necessary to interpose a plurality of bearings. . As a result, the coaxial accuracy of the left and right fixed shafts is reduced due to the backlash of the bearing as described above.

  The present invention has been made in view of such circumstances, and its purpose is to improve the coaxial accuracy of a pair of fixed shafts protruding from the left and right sides of the hub, and to suppress the generation of vibration, abnormal noise and noise, and to improve the riding comfort. It is providing the in-wheel motor which can contribute to.

  In order to solve the above-described problems, an in-wheel motor according to an aspect of the present invention includes a cylindrical hub to which a wheel is to be coupled to the outer periphery, and a first that penetrates one surface of the hub and rotatably supports the hub. A fixed shaft member, a second fixed shaft member that is coaxial with the first fixed shaft member, passes through the other surface side of the hub and rotatably supports the hub, and is disposed inside the hub, and the first fixed shaft member passes through the first fixed shaft member. And a motor base fixed to the first fixed shaft member, a stator fixed to the motor base, a rotor disposed in an inner peripheral region of the stator and rotatably supported by the first fixed shaft member, a second A reduction mechanism that has a through-hole that is coaxial with the fixed shaft member and that receives a rotational force from the rotor to reduce the rotational speed of the rotor, is fixed to the inner peripheral surface of the hub, and is connected to the output side gear of the reduction mechanism. Ring-shaped internal gear And a third fixed shaft member for connecting the first fixed shaft member and the second fixing shaft member through the mouth with them on the axis, a.

  According to this aspect, the third fixed shaft member that penetrates the through hole formed in the speed reduction mechanism inside the hub directly connects the first fixed shaft member and the second fixed shaft member on the axis thereof. The coaxial accuracy of the fixed shaft member and the second fixed shaft member can be improved. Further, by directly connecting the first fixed shaft member and the second fixed shaft member by the third fixed shaft member, the shaft rigidity can be improved and the coaxial accuracy can be maintained. As a result, it is possible to suppress the occurrence of vibration, abnormal noise, and noise of the in-wheel motor.

  ADVANTAGE OF THE INVENTION According to this invention, the in-wheel motor which improves the coaxial precision of a pair of fixed shaft member which protrudes from the right and left of a hub, suppresses generation | occurrence | production of a vibration, abnormal noise, and noise, and can contribute to improvement of riding comfort can be provided. .

It is an enlarged view of the wheel part of the vehicle to which the in-wheel motor of this embodiment is applied. It is sectional drawing for demonstrating the internal structure of the in-wheel motor of this embodiment. It is explanatory drawing explaining an example of the other connection method of the 1st fixed shaft member of the in-wheel motor of this embodiment, a 2nd fixed shaft member, and a 3rd fixed shaft member. It is explanatory drawing explaining the insertion position of the washer in the gear fixed shaft of the planetary gear of the in-wheel motor of this embodiment. It is explanatory drawing explaining the shape and mounting position of the elastic member with which the gear fixed axis | shaft of the planetary gear of the in-wheel motor of this embodiment is mounted | worn.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention (hereinafter referred to as embodiments) will be described with reference to the drawings. The same or equivalent components and members shown in the drawings are denoted by the same reference numerals, and repeated descriptions are appropriately omitted. In addition, the dimensions of the members in each drawing are appropriately enlarged or reduced for easy understanding. In addition, in the drawings, some of the members that are not important for describing the embodiment are omitted.

  FIG. 1 is an enlarged view of a wheel portion of a vehicle to which the in-wheel motor of the present embodiment is applied. The in-wheel motor 10 incorporates a motor inside a cylindrical hub 12, and one end side of a plurality of spokes 14 extending radially is fixed to the outer periphery of the hub 12. Further, the other end side of the spoke 14 is fixed to a rim 18 that supports the tire portion 16. The rim 18 is joined to the hub 12 and the spoke 14 to form a wheel skeleton. Further, a first fixed shaft member 20 protruding from the hub 12 (in the case of FIG. 1, only the first fixed shaft member 20 protruding from one side of the hub 12 is shown) is fixedly supported on a fork 22 which is a part of the vehicle frame. Has been. Therefore, the wheel including the hub 12, the spoke 14, the tire portion 16, and the rim 18 is configured to rotate around the first fixed shaft member 20 and the second fixed shaft member paired with the first fixed shaft member 20. Yes.

  In the case of FIG. 1, the wheel is a so-called spoke wheel including the hub 12, the spoke 14, the tire portion 16, and the rim 18, but a so-called disc wheel using a disk instead of the spoke 14 may be used. .

  FIG. 2 is a cross-sectional view for explaining the internal structure of the in-wheel motor 10. The in-wheel motor 10 is roughly divided into a hub 12, a first fixed shaft member 20 and a second fixed shaft member 24 projecting from the left and right of the hub 12, a motor unit 26 housed in the hub 12, and a speed reduction mechanism 28. It consists of and.

  The hub 12 is a cylindrical part to which a wheel is to be coupled to the outer periphery. In the present embodiment, the hub 12 seals the cup-shaped first member 30 having an opening 30a on one surface and the opening 30a. It is comprised with the disk-shaped or lid-shaped 2nd member 32 to stop. The hub 12 can be formed of iron, casting, stainless steel, or the like. In the case of FIG. 2, the first member 30 is a cup-shaped integral part composed of a cylindrical body and a bottom that closes the body, but is not limited thereto. For example, the body portion and the bottom portion may be separately formed and combined. As a coupling method between the body portion and the bottom portion, a known coupling method such as welding or screw coupling can be used. As described above, when the hub 12 includes the lid-shaped second member 32, the inside of the hub 12 can be easily exposed by attaching and detaching the second member 32, which can contribute to improvement in assembling property and workability during maintenance. Although the hub 12 is not required to be completely airtight, it is preferable to achieve a waterproof level that does not allow water or the like to enter. For example, it is preferable to provide a waterproof sealing function by interposing an O-ring or the like at the joint between the first member 30 and the second member 32. Further, the labyrinth between the second member 32 on the rotating side and the first fixed shaft member 20 on the fixed side, or between the first member 30 on the rotating side and the second fixed shaft member 24 on the fixed side. May be provided to suppress the ingress of liquid.

  The lid-shaped second member 32 constituting the hub 12 has a through-opening 32 a that allows the first fixed shaft member 20 to pass through a central portion that is coaxial with the rotation center of the hub 12. A second bearing 32 that supports the second member 32, that is, the hub 12 so as to be rotatable, is fixed to the portion of the second member 32 corresponding to the through-hole 32a. In addition, on the inner side of the second member 32, that is, in the hub 12, a motor base 36 that serves as a base of the motor unit 26 is fixed to the first fixed shaft member 20. As shown in FIG. 2, the motor base 36 is formed with a bearing hole 36a through which the first fixed shaft member 20 passes, and the first fixed shaft member 20 is fixed by press-fitting, welding, or a combined process thereof. . Therefore, the motor base 36 is integrated with the first fixed shaft member 20, and the second member 32, that is, the hub 12 is configured to rotate around the motor base 36.

  The first fixed shaft member 20 is made of, for example, iron or stainless steel. As shown in FIG. 2, a line hole 20a through which a drive line 38 such as a signal line or a power line for driving the motor unit 26 passes is formed. ing. In the case of FIG. 2, the line hole 20 a is drawn with a relatively large diameter for the sake of explanation, but it is sufficient that the diameter is sufficient to allow the drive line 38 to be routed. Therefore, the diameter of the first fixed shaft member 20 and the diameter of the line hole 20a can provide rigidity capable of withstanding an additional load determined in consideration of the own weight of the vehicle to which the in-wheel motor 10 is assembled, the loaded weight of the vehicle, and the like. It is desirable to select as appropriate. Further, a connecting hole 20b for connecting a third fixed shaft member 40 to be described later is formed at the end of the first fixed shaft member 20 on the inner side of the hub 12.

  Similarly, the cup-shaped first member 30 constituting the hub 12 has a through-opening 30 b that allows the second fixed shaft member 24 to pass through a central portion that is coaxial with the rotation center of the hub 12. A second bearing 42 that rotatably supports the first member 30, that is, the hub 12, is fixed to a portion corresponding to the through hole 30 b of the first member 30 with the second fixed shaft member 24 as an axis. A gear case 44 constituting a part of a speed reduction mechanism 28 for reducing the rotational speed of the motor unit 26 is fixed to the second fixed shaft member 24 on the inner side of the first member 30, that is, in the hub 12. To be placed. As shown in FIG. 2, the gear case 44 is formed with a bearing hole 44a through which the second fixed shaft member 24 passes, and the second fixed shaft member 24 is fixed by press-fitting, welding, or a combined process thereof. . The second fixed shaft member 24 is made of, for example, iron or stainless steel, and a connection hole 24 a for connecting a third fixed shaft member 40 described later is formed at the inner end of the hub 12. A ring-shaped internal gear 46 that meshes with the output side gear of the speed reduction mechanism 28, that is, a planetary gear described later, is fixed to the cup-shaped inner peripheral surface of the first member 30. As described above, since the gear case 44 is fixed and integrated with the second fixed shaft member 24, when the internal gear 46 is rotated by the rotation of the output side gear of the speed reduction mechanism 28, the second fixed shaft member 24 is rotated. The first member 30, that is, the hub 12 rotates around the speed reduction mechanism 28. As described above, since the gear case 44 is fixed to the second fixed shaft member 24, the planetary gear 62 is restricted from revolving with respect to the second fixed shaft member 24 or the first fixed shaft member 20. Thus, it is supported by the gear case 44.

The motor unit 26 includes a motor base 36, a stator core 48, a coil 50, a rotor core 52, a magnet 54, and the like.
In the case of this embodiment, the motor base 36 has a cup shape and is formed of metal, resin, or a composite thereof. The cup-shaped motor base 36 accommodates therein a stator core 48 around which the coil 50 is wound and a rotor core 52 to which a ring-shaped magnet 54 is fixed.

  The stator core 48 is formed by laminating a magnetic material such as a silicon steel plate and then subjecting the surface to insulation coating by electrodeposition coating or powder coating. The stator core 48 is fixed to the motor base 36 by fastening means such as a plurality of screws 56. The stator core 48 has a ring shape having a plurality of salient poles (not shown) projecting inward, and a coil 50 is wound around each salient pole. The winding end of the coil 50 is connected to a drive line 38 drawn from the bottom surface of the motor base 36 via a connector or the like, and the coil 50 is supplied with electric power necessary for generating a magnetic field.

  The rotor core 52 is disposed in the inner peripheral region of the stator including the stator core 48 and the coil 50. The rotor core 52 is obtained by processing iron into a ring shape by cutting or the like, and fixing a ring-shaped magnet 54 on the outer peripheral surface side. On the inner peripheral surface side, an outer ring of a third bearing 58 in which the inner ring side is press-fitted and fixed to the first fixed shaft member 20 is press-fitted and fixed. When a three-phase substantially sinusoidal current is passed through the coil 50 by a predetermined drive circuit, the coil 50 generates a rotating magnetic field at the salient pole of the stator core 48. Then, a rotational driving force is generated by the interaction between the driving magnetic pole of the magnet 54 and the rotating magnetic field, and the rotor core 52 can rotate around the first fixed shaft member 20 at a speed corresponding to the amount of current.

  In the present embodiment, the motor base 36 is formed in a cup shape, so that the exposure opening 36 b is formed so that at least a part of the stator core 48 and the coil 50, that is, the stator is exposed inside the hub 12. The coil 50 generates heat when the motor unit 26 is driven. The heat generated in the coil 50 is transferred to the motor base 36 through the stator core 48 and radiated. In this embodiment, the motor base 36 has an exposure port 36b and one surface of the stator including the coil 50 is connected to the inside of the hub 12. The heat dissipation effect is enhanced by exposing to the surface. Thus, by forming the exposure port 36b, compared with the case where the motor part 26 whole is covered with a casing, heat dissipation efficiency increases and it can suppress the fall of the motor performance by heat_generation | fever. Further, since the exposure port 36b is opened to the speed reduction mechanism 28 that is rotationally driven when the motor is driven, heat can be diffused and cooled by the rotational drive of the speed reduction mechanism 28, and the heat dissipation efficiency can be further increased. .

The speed reduction mechanism 28 includes a gear case 44, a sun gear 60, a plurality of planetary gears 62, an internal gear 46, and the like.
A plurality of gear fixed shafts 64 that support the planetary gears 62 are implanted in the gear case 44 fixed to the second fixed shaft member 24. The gear fixed shaft 64 supports the planetary gear 62 in a freely rotatable manner. The planetary gears 62 are arranged at equal intervals around the sun gear 60 arranged coaxially with the first fixed shaft member 20 and the second fixed shaft member 24 so that the positions of the planetary gears 62 are not biased. Yes. By arranging in this way, each planetary gear 62 is equally torqued. That is, smooth rotation and damage suppression of the planetary gear 62 are realized so that no stress is applied to the specific planetary gear 62. Therefore, it is necessary to arrange at least two planetary gears 62. The number of planetary gears 62 can be appropriately selected according to the torque required for the vehicle to which the in-wheel motor 10 is applied because the load on each planetary gear 62 can be reduced as the number increases. desirable. That is, the number of planetary gears 62 is two or more, and can be appropriately selected from the number that can be accommodated on the inner peripheral side of the internal gear 46. However, as the number of planetary gears 62 increases, the number of parts increases and the number of manufacturing steps increases. As a result of simulation, the present applicant confirmed that the number of man-hours for manufacturing is not an obstacle to practical use if the number of planetary gears 62 is 5 or less. Therefore, it is desirable that the number of planetary gears 62 be 2 to 5, and in the present embodiment, the optimum number of planetary gears 62 is set to 3 in view of the load reduction of each planetary gear 62 and the balance of manufacturing man-hours. Yes. Note that FIG. 2 shows a state where two planetary gears 62 are visible.

  As described above, the first fixed shaft member 20 has the connection hole 20b, and the second fixed shaft member 24 has the connection hole 24a. The third fixed shaft member 40 is inserted into the connecting hole 20b and the connecting hole 24a, and connects the first fixed shaft member 20 and the second fixed shaft member 24 on their axes. By directly connecting the first fixed shaft member 20 and the second fixed shaft member 24 on the axis by the third fixed shaft member 40, the coaxial accuracy between the first fixed shaft member 20 and the second fixed shaft member 24 is improved. Can do. That is, the vibration caused by the coaxial performance when the hub 12 rotates can be suppressed, and the generation of abnormal noise and noise accompanying the vibration can also be suppressed. Further, the first fixed shaft member 20 and the second fixed shaft member 24 are directly connected by the third fixed shaft member 40, whereby the first fixed shaft member 20 and the second fixed shaft member 24 are configured as one fixed shaft. As a result, the rigidity of the fixed shaft as a whole can be improved. As a result, the distortion of the member due to the vehicle's own weight or the mounted weight can be suppressed and the coaxial accuracy can be maintained, thereby contributing to the suppression of vibration, abnormal noise, and noise. For joining the first fixed shaft member 20 and the second fixed shaft member 24 and the third fixed shaft member 40, press-fitting, welding, adhesion, or the like can be used, and these can be used alone or in combination. it can. If the first fixed shaft member 20, the second fixed shaft member 24, and the third fixed shaft member 40 are within the allowable range of coaxial accuracy when connected, the first fixed shaft member 20 and the second fixed shaft member 24 are used. The third fixed shaft member 40 may be joined by a clearance fit. In this case, disassembly at the time of maintenance becomes easy and workability can be improved.

  Similar to the first fixed shaft member 20 and the second fixed shaft member 24, the third fixed shaft member 40 can be formed of iron or stainless steel. The third fixed shaft member 40 rotatably supports a gear holder 66 fixed so as to straddle the inner peripheral side of the ring-shaped rotor core 52 and the outer ring of the third bearing 58. A sun gear 60 having the third fixed shaft member 40 as the rotation center is fixed to the gear holder 66. In other words, the sun gear 60 rotates as the rotor core 52 rotates. As described above, the sun gear 60 is engaged with the plurality of planetary gears 62. The planetary gear 62 includes a first planetary gear 62 a that meshes with the sun gear 60 and a second planetary gear 62 b that meshes with the internal gear 46. Both the first planetary gear 62a and the second planetary gear 62b rotate around the gear fixed shaft 64 as a central axis. The first planetary gear 62a and the second planetary gear 62b may be formed separately and fixed to the gear fixed shaft 64, or the first planetary gear 62a and the second planetary gear 62b may be formed integrally to form the gear fixed shaft 64. It may be fixed to.

The present inventors have confirmed through various simulations that the reduction ratio of the speed reduction mechanism 28 is preferably 6 to 21 in the in-wheel motor 10 of the present embodiment, for example.
The reduction ratio is as follows when the number of teeth of the sun gear 60 is Za, the number of teeth of the internal gear 46 is Zc, the number of teeth of the first planetary gear 62a is Z1, and the number of teeth of the second planetary gear 62b is Z2. It becomes like this.
Reduction ratio ≒ (Z1 / Za) x (Zc / Z2)
Here, since the sizes of the teeth of the meshing gears, that is, the sizes of the teeth of the sun gear 60, the first planetary gear 62a, and the second planetary gear 62b, and the internal gear 46 are generally the same, The number of teeth can be considered to be proportional to the circumference of the corresponding gear. Therefore, the reduction ratio can be simply expressed by the following calculation formula using the reference pitch circle diameter of the gear. That is, the reference pitch circle diameter of the sun gear 60 is Da, the reference pitch circle diameter of the internal gear 46 is Dc, the reference pitch circle diameter of the first planetary gear 62a is D1, and the reference pitch circle diameter of the second planetary gear 62b is D2. When it becomes, it becomes as follows.
Reduction ratio ≒ (D1 / Da) x (Dc / D2)
Here, the inventors consider the required shaft strength of the sun gear 60 and the assembly workability of the entire in-wheel motor 10 for the lower limit value of the reference pitch circle diameter of the sun gear 60 in the configuration of the in-wheel motor 10 of the present embodiment. And examined. As a result, it is confirmed that the performance required for the in-wheel motor 10 can be maintained by setting D1 = 50.0 mm, D2 = 16.2 mm, and Dc = 77.2 mm with Da = 11.0 mm as the lower limit. did. The reduction ratio in this case was 21.7.

  Further, the inventors set the size and weight of the in-wheel motor 10, the internal space of the hub 12, the in-wheel motor 10, and the upper limit value of the sun gear 60 reference pitch circle diameter in the configuration of the in-wheel motor 10 of the present embodiment. Considered the whole assembly workability. As a result, by setting Da = 27.6 mm as an upper limit value and setting D1 = 33.4 mm, D2 = 16.2 mm, and Dc = 77.2 mm, the size and weight restrictions required for the in-wheel motor 10 are reduced. Confirmed to meet. The reduction ratio in this case was 5.77.

  In addition, the inventors have Da = 13.2 mm, D1 = 47.8 mm, D2 = 16.2 mm, and Dc = 77.2 mm, the shaft strength of the sun gear 60 and the assembly workability of the in-wheel motor 10 as a whole, It was confirmed that the optimum value satisfies the size and weight restrictions in a well-balanced manner. In this case, the reduction ratio is 17.3. As described above, the reduction ratio is within the range of 6 to 21, and the sun gear 60, the first planetary gear 62a, the second planetary gear 62b, and the internal gear depending on the type and application of the vehicle on which the in-wheel motor 10 is mounted. It is desirable to select and determine the 46 standard pitch circle diameter and the number of teeth as appropriate.

  By the way, as shown in FIG. 2, the in-wheel motor 10 of this embodiment has the through-hole 66a in the center part of the sun gear 60 which comprises the deceleration mechanism 28, and this through-hole 66a is used for the 3rd fixed shaft member 40. Penetrates to connect the first fixed shaft member 20 and the second fixed shaft member 24 on the axis. As a result, the first fixed shaft member 20 and the second fixed shaft member 24 are directly connected to each other without receiving interference from other components and without complicating the internal structure of the hub 12. While improving the coaxial precision of the shaft member 20 and the 2nd fixed shaft member 24, shaft rigidity is improved.

The operation of the in-wheel motor 10 configured as described above will be described.
By adjusting the opening of an accelerator device provided in a vehicle (not shown), a three-phase substantially sinusoidal current is passed through the drive line 38 from a drive circuit (not shown). As a result, the coil 50 generates a rotating magnetic field at the salient pole of the stator core 48. Then, a rotational driving force is generated by the interaction between the driving magnetic pole of the magnet 54 and the rotating magnetic field, and the rotor core 52 is rotated. Since the rotor core 52 is connected to the sun gear 60 via the gear holder 66, the rotor core 52 and the sun gear 60 rotate at the same speed. The sun gear 60 meshes with the first planetary gear 62a of the planetary gear 62, the first planetary gear 62a is coaxially joined with the second planetary gear 62b, and the second planetary gear 62b meshes with the internal gear 46. ing. Accordingly, the first member 30 to which the internal gear 46 is fixed is rotated by the rotation of the rotor core 52. The first member 30 and the second member 32 are integrated as a hub 12 by a fastening member such as a screw 68, and rotate using the first fixed shaft member 20 and the second fixed shaft member 24 as fixed rotation shafts. That is, the hub 12, that is, the wheels rotate with respect to the vehicle body to which the first fixed shaft member 20 and the second fixed shaft member 24 are fixed, thereby realizing the traveling of the vehicle.

  FIGS. 3A to 3C are explanatory views for explaining another structural example of the connection structure of the first fixed shaft member 20, the second fixed shaft member 24, and the third fixed shaft member 40. In the case of FIG. 2, the first fixed shaft member 20, the second fixed shaft member 24, and the third fixed shaft member 40 are formed as separate parts, and the joining methods such as press-fitting, welding, and bonding are used alone or in combination. An example of direct connection was shown. The example of FIG. 3A is an example in which the first fixed shaft member 20 and the third fixed shaft member 40 are integrally formed to form the fixed shaft 70. The third fixed shaft member 40 side of the fixed shaft 70 is directly connected to the connection hole 24a of the second fixed shaft member 24 by using a joining method such as press-fitting, welding, or adhesion alone or in combination.

  Similarly, the example of FIG. 3B is an example in which the second fixed shaft member 24 and the third fixed shaft member 40 are integrally formed to form the fixed shaft 72. The third fixed shaft member 40 side of the fixed shaft 72 is directly connected to the connection hole 20b of the first fixed shaft member 20 by using a joining method such as press-fitting, welding, or adhesion alone or in combination. As described above, the third fixed shaft member 40 is integrally formed on one of the first fixed shaft member 20 and the second fixed shaft member 24, so that the components can be compared with the case where each fixed shaft is a separate component. It is possible to reduce the number of points and manufacturing man-hours and improve the shaft rigidity.

  FIG. 3C is an example in which the first fixed shaft member 20, the second fixed shaft member 24, and the third fixed shaft member 40 are integrated into a fixed shaft 74. In this case, it is possible to further reduce the number of parts and the number of manufacturing steps, improve the shaft rigidity, and the like from the example of FIGS. 3 (a) and 3 (b). However, in the case of FIG. 3C, it is necessary to rotatably support the gear holder 66 and the sun gear 60 at a portion corresponding to the third fixed shaft member 40. In order to enable assembly in the case of such a structure, it is necessary to make the portion corresponding to the third fixed shaft member 40 the same diameter or larger than the first fixed shaft member 20 and the second fixed shaft member 24. is there. By increasing the diameter of the portion corresponding to the third fixed shaft member 40, it becomes necessary to increase the reference pitch circle diameter of the sun gear 60 and to reduce the reference pitch circle diameter of the planetary gear 62. It is preferable to determine the use of the fixed shaft 74 in consideration of the above.

  In the structure of the in-wheel motor 10 shown in FIG. 2, the planetary gear 62 employs a structure that rotates around the gear fixed shaft 64 without using a bearing or the like. Therefore, the upper and lower support end surfaces 62 slide on the supported surface. As a result, the support end surface of the planetary gear 62 supported by the gear fixed shaft 64 may be worn at an early stage during rotation. In the present embodiment, as shown in FIG. 4, the planetary gear 62 moves in the axial direction of the gear fixed shaft 64 to the gear fixed shaft 64 implanted in the gear case 44 fixed to the second fixed shaft member 24. A pair of ring-shaped washers 76 for restricting the operation are provided, and the planetary gear 62 is sandwiched and positioned. The washer 76 is configured to rotate together with the planetary gear 62. For example, the engaging claw formed on the washer 76 is engaged with the end face of the planetary gear 62. As a result, when the planetary gear 62 is rotated, the washer 76 is brought into contact with the fixed portion of the gear case 44 and the gear fixing shaft 64 so that the washer 76 is worn first. Therefore, the maintenance of the in-wheel motor 10 is performed based on the wear of the washer 76, and the replacement part can be made only by the washer 76. As a result, the maintenance cost of the in-wheel motor 10 can be reduced.

  The washer 76 can be formed using a metal such as stainless steel, iron, or copper. The washer 76 may be formed of a self-lubricating material. For example, the washer 76 may be formed of PEEK (polyether ether ketone). PEEK is a thermoplastic super heat-resistant polymer resin that has excellent fatigue resistance, impact resistance, and creep resistance, and that can be used for chemical resistance other than concentrated sulfuric acid, and has little elution of gas and metal ions. It is suitable for use in an in-wheel motor 10 that requires heat resistance, impact resistance, corrosion resistance, and the like. The washer 76 may be adjusted in durability by adjusting its thickness or by laminating.

  FIG. 5A is a perspective view showing an example of an elastic bracket 78 for improving the support stability of the planetary gear 62. The elastic bracket 78 functions as an elastic member that applies an elastic force between the gear case 44 and the planetary gear 62, and biases the planetary gear 62 in a predetermined direction, for example, a direction away from the gear case 44. Generate power. The elastic bracket 78 can be formed, for example, by punching and deforming a plate-shaped spring steel by pressing or the like. FIG. 5B is an explanatory diagram for explaining a state in which the elastic bracket 78 is interposed between the gear case 44 and the planetary gear 62. By energizing the planetary gear 62 in a certain direction (in the direction of arrow A in the figure) by the elastic bracket 78, the planetary gear 62 is energized to a fixing member such as a fixing ring 80 attached to the tip of the gear fixing shaft 64. Thus, vibration (flapping) is suppressed in the axial direction of the gear fixed shaft 64 when the planetary gear 62 rotates. In this way, by suppressing the vibration of the planetary gear 62 in the axial direction of the gear fixed shaft 64, it is possible to realize vibration suppression of the entire in-wheel motor 10, noise suppression, reduction of wear of the planetary gear 62, and the like.

  In the case of FIG. 5B, an example in which a washer 76 is interposed on the upper surface of the elastic bracket 78 is shown. In this case, the elastic bracket 78 urges the planetary gear 62 together with the washer 76, and the washer 76 and the planetary gear 62 rotate on the elastic bracket 78. Also. The washer 76 on the elastic bracket 78 may be omitted, and the planetary gear 62 may be biased and supported only by the elastic bracket 78. In this case, the elastic bracket 78 does not rotate with the planetary gear 62. Therefore, the elastic bracket 78 may be made of a self-lubricating material, or the upper surface of the elastic bracket 78 may be coated with a lubricating layer to reduce the wear of the planetary gear 62.

  5A shows an example in which the elastic bracket 78 has a circular opening through which the gear fixing shaft 64 can be inserted. However, the shape of the elastic bracket 78 only needs to generate a biasing force with respect to the planetary gear 62. For example, the insertion portion of the gear fixed shaft 64 may be U-shaped so that the gear fixed shaft 64 can be mounted from the lateral direction. Further, the elastic bracket 78 may be disposed at the upper and lower positions of the planetary gear 62. In this case, the planetary gear 62 may be positioned at the center of the gear fixed shaft 64 with the urging force of the pair of elastic brackets 78 being the same. Further, the biasing force may be varied to bias to one side.

  In the present embodiment, an example of the in-wheel motor 10 applied to an electric vehicle that is completely covered by the control of the motor unit 26 from the stop state to the maximum speed is shown. In the modified example, for example, a clutch mechanism may be provided inside the hub 12 so as to have an electric assist specification. For example, when the in-wheel motor 10 is used as a drive unit of an electrically assisted bicycle, a clutch mechanism is connected to the in-wheel motor 10 at the time of starting, and motor assist by the motor unit 26 is performed. Then, the clutch mechanism may be disengaged when the predetermined speed is exceeded or the driver requests, and the bicycle may be driven only by the pedal rotational force. In addition, the in-wheel motor 10 may provide a level of assist corresponding to the torque by incorporating a detector (torque) for riding the bicycle into the circuit. Furthermore, the in-wheel motor 10 of this embodiment may be combined with another drive source, and a plurality of drive sources including the in-wheel motor 10 may be used in the simultaneous use mode or in the selective use mode.

  In the above-described embodiment, the structure and effect have been described without specifying the vehicle on which the in-wheel motor 10 is mounted. Examples of the vehicle to which the in-wheel motor 10 is applied include, for example, an electric motorcycle, There are electric wheelchairs, motorized scooters, electric carts, golf carts, electric bicycles, and the like. Thus, the in-wheel motor 10 of this embodiment can comprise a self-propelled type wheel or a torque assist type wheel, and can obtain the same effect as the example mentioned above.

  The configuration of the in-wheel motor according to the embodiment has been described above. These embodiments are merely examples, and it is needless to say that they merely illustrate the principles and applications of the present invention. In the embodiment, many modifications and arrangements can be made without departing from the spirit of the present invention defined in the claims, and such modifications are also within the scope of the present invention. That is understood by the contractor.

  10 in-wheel motor, 12 hub, 20 first fixed shaft member, 24 second fixed shaft member, 28 speed reduction mechanism, 30a opening, 30 first member, 30b through port, 32 second member, 32a through port, 36 motor Base, 36b Exposed port, 40 Third fixed shaft member, 44 Gear case, 48 Stator core, 52 Rotor core, 60 Sun gear, 62 Planetary gear, 64 Gear fixed shaft, 66a Through port, 70, 72, 74 Fixed shaft, 76 Washer .

Claims (9)

A cylindrical hub to which a wheel should be coupled to the outer periphery;
A first fixed shaft member that passes through one side of the hub and rotatably supports the hub;
A second fixed shaft member that is coaxial with the first fixed shaft member and penetrates the other surface side of the hub and rotatably supports the hub;
A motor base disposed inside the hub, through which the first fixed shaft member passes and fixed to the first fixed shaft member;
A stator fixed to the motor base;
A rotor disposed in an inner peripheral region of the stator and rotatably supported by the first fixed shaft member;
A speed reduction mechanism that has a through-hole that is coaxial with the second fixed shaft member and receives a rotational force from the rotor to reduce the rotational speed of the rotor;
A ring-shaped internal gear fixed to the inner peripheral surface of the hub and connected to the output side gear of the speed reduction mechanism;
A third fixed shaft member for connecting the first fixed shaft member and the second fixed shaft member on their axes via the through hole;
An in-wheel motor comprising:   The in-wheel motor according to claim 1, wherein the third fixed shaft member is integrally formed with at least one of the first fixed shaft member and the second fixed shaft member.   The in-wheel motor according to claim 1, wherein the motor base has an exposure port that exposes at least a part of the stator inside the hub.   The said hub is comprised by the cup-shaped 1st member which has an opening part in one surface, and the disk-shaped 2nd member which seals the said opening part, The Claims 1-3 characterized by the above-mentioned. The in-wheel motor of any one of these.   The in-wheel motor according to any one of claims 1 to 4, wherein a reduction ratio of the reduction mechanism is 6 to 21.   The said reduction mechanism is comprised by the sun gear of the input side, and the several planetary gear meshing with it, The number of the said planetary gears is 2-5, The any one of Claims 1-5 characterized by the above-mentioned. In-wheel motor as described in.   The planetary gear is a pair of washers that rotate together with the planetary gear while restricting movement of the gear fixed shaft in the axial direction on a gear fixed shaft implanted in a gear case fixed to the second fixed shaft member. The in-wheel motor according to claim 6, wherein the in-wheel motor is sandwiched and positioned.   The in-wheel motor according to claim 7, wherein the washer is formed of a self-lubricating material.   The in-wheel motor according to claim 7, wherein an elastic member is interposed between the gear case and the planetary gear.

Images