JP2009090982A - Hub unit for motor-driven wheel and vehicle provided with the same hub unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance a cooling effect of a motor of a hub unit of an assist bicycle. <P>SOLUTION: This hub unit has a motor 9 provided with a stator 3 and a rotor 4, and a hub 7 storing the motor 9 therein and rotated and driven by rotation of the rotor 4. The hub unit is provided with a pump 8 to discharge air in the hub 7 according to rotation of the hub 7. Intake of outside air is performed from a ventilation hole 59 formed in the hub 7 by discharge of air in the hub 7 accompanying an operation of the pump 8, the outside air is supplied to the motor 9 to cool the motor 9, and overheat of the motor 9 is surely prevented. A tube is connected to the ventilation hole 59, and an end portion of the tube is extended to a place where water does not enter. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a hub unit for an electric wheel and a vehicle such as an assist bicycle or a wheelchair provided with the hub unit.

Conventionally, when a hub unit incorporating a motor or the like is mounted on the wheel hub of a bicycle, and the load of a certain value or more is applied to the pedal of the bicycle, the motor is driven to run easily on a slope. For example, Japanese Patent Laid-Open Publication No. 2002-514550 discloses an electric bicycle that can perform the above.
Special table 2002-514550

  The hub unit generates heat by energizing the motor. When the motor is overheated, the motor cannot be rotated with a high torque. Therefore, a device for releasing the heat of the motor is required.

  However, in the configuration of Patent Document 1, since the motor housing surrounds the stator in a sealed state, the stator cannot be radiated effectively.

  For this reason, cooling liquid is accommodated in the hub, and the motor housing is cooled from the outside to suppress the heat generation of the winding. When the coolant is stored in the hub, it is necessary to take measures against the liquid leakage, resulting in high costs. Further, the weight is increased by the amount of the coolant.

  The present invention clarifies a hub unit that can enhance the cooling effect of a motor and prevent heating, and a vehicle including the hub unit.

  An electric wheel hub unit of the present invention is an electric wheel hub unit having a motor including a stator and a rotor, and a hub that accommodates the motor therein and is driven to rotate by rotation of the rotor. A fixing support shaft protruding in a fixed manner with respect to the motor housing on the rotation center shaft of the hub and protruding outside the hub is provided, and a ventilation hole for taking in outside air is formed in the vicinity of the fixing support shaft. A tube is connected to the air hole, and the end of the tube is extended to a place where water of the electric vehicle does not enter, and as the hub rotates, outside air is taken into the hub through the air hole to cool the motor. A motor cooling means is provided.

  Preferably, the hub is formed with a pump mechanism that is operated by a protrusion formed on the outer periphery of the motor housing and discharges air in the hub.

  The stator is preferably configured by bolting a pair of end plates arranged opposite to each other with a laminated metal plate interposed therebetween, and the outer peripheral surface of the stator opens between the end plates to the inner surface of the hub.

  It is preferable that a planetary gear mechanism that is operated by rotation of the rotor is housed in the hub, and an inner tooth that meshes with the planetary gear of the planetary gear mechanism is provided on the inner surface of the hub.

  According to the present invention, the motor can be automatically and efficiently cooled by the outside air taken in with the rotation of the hub, and overheating of the motor can be surely prevented.

  As in the prior art, it is not necessary to contain the coolant in the hub to suppress overheating of the windings. The cylinder wall of the motor housing can be omitted, and the labor for accommodating the coolant is not required, so that the manufacturing cost can be reduced. Further, it is possible to contribute to weight reduction by omitting the cylindrical wall and the coolant. Furthermore, since the outer diameter of the stator can be increased by the amount that the cylindrical wall does not exist, the power of the rotational force can be increased.

It is a front view of an electrically assisted bicycle. It is sectional drawing of a hub unit. It is sectional drawing seen from the other direction of the hub unit. It is sectional drawing seen from the other direction of the hub unit. It is an exploded perspective view of a laminated metal plate.

FIG. 1 shows an example of an electrically assisted bicycle 1 having a hub unit 2 of the present invention.

  A hub unit 2 is attached to the tip of the front fork 12 of the assist bicycle 1, and the rim 13 of the front wheel 11 and the hub unit 2 are connected by spokes 14 and 14.

  A battery 17 is mounted between the seat post 15 and the rear wheel 16. A sensor (not shown) for energizing the motor 9 of the hub unit 2 from the battery 17 when the pedal load reaches a certain value is provided at an appropriate place where the depression force of the pedal 18 acts.

  The hub unit 2 basically includes a motor 9 having a stator 3 and a rotor 4, a hub 7 that accommodates the motor inside and is rotationally driven by the rotation of the motor 9, and a hub 7. And a support shaft 57 for fixing projecting out of the hub 7 in a fixed state with respect to the motor housing 5.

  As shown in FIG. 5, the laminated metal plate 31 of the stator 3 is formed by laminating a predetermined number of punched metal plates 31a. The punched metal plate 31a is provided with a plurality of, in the embodiment, twelve T-shaped convex portions 31b projecting toward the center of the ring at equal intervals in the circumferential direction on the inner periphery of the ring.

  A winding 32 is applied to each laminated convex portion 31b in which the phases of the laminated metal plates 31 are aligned. Conventionally, the laminated metal plate 31 is formed by laminating a metal plate material with a punching die to form the punched metal plate 31a, and at the same time with the punched posture.

  For this reason, the positions of the burrs generated in each punched metal plate 31a are aligned in the adjacent punched metal plates 31a and 31a.

  If burrs are uniformly generated in the circumferential direction in one punched metal plate 31a, the thickness of one laminated metal plate 31 is uniform.

  However, the above is hardly possible, and if one punched metal plate 31a is observed, the position of the burr is not uniform in the circumferential direction. In this case, if the punched metal plates 31a that are continuously punched are simply laminated, the thickness of the single laminated metal plate 31 is about 0.1 to 0.3 mm, but a thick portion and a small portion are generated.

  For reasons to be described later, it is necessary to suppress the generation of a thick portion and a small portion in the laminated metal plate 31. For this reason, the laminated metal plate 31 is divided into a plurality of unit bodies 31c made up of a unit number of punched metal plates 31a, and the unit bodies are stacked with a predetermined angle shift.

In the embodiment, the laminated metal plate 31 is formed by sequentially shifting 360 ° by an angle obtained by dividing the number of unit bodies 31c. For example, when the number of the unit bodies 31c is 3, the three unit bodies 31c are shifted by 120 ° and the windings 32 are applied to the respective stacked convex portions 31b.
When the laminated metal plate 31 is punched out of a metal plate and laminated while forming the punched metal plate 31a, each time the punched metal plate 31a is punched out by the number of unit bodies 31c, the metal plate material is cut at a predetermined angle in a horizontal plane. In the embodiment, it can be easily formed by rotating 120 °.

  Note that the number of inwardly protruding portions 31b of the punched metal plate 31a is limited to a number that is divisible by the number of unit bodies 31c.

  A rotor 4 is disposed in the stator 3 so as to be rotatable concentrically with the stator 3. The rotor 4 is formed at the center of the circular laminated metal plate 42 through the rotating shaft 41 so as to be integrally rotatable with the laminated metal plate 42.

  A plurality of permanent magnets 43 are embedded in the outer peripheral portion of the laminated metal plate 42 in parallel with the rotation shaft 41 at equal intervals in the circumferential direction of the laminated metal plate 42 with alternating S and N poles.

  The housing 5 of the motor 9 sandwiches the laminated metal plate 31 of the stator 3 between the first and second pair of end plates 51 and 52 from the axial direction of the stator 3, and the both end plates 51 and 52 are laminated on the laminated metal plate 31. Are tightened with a plurality of tightening bolts 53 penetrating the outer peripheral portion. The fastening of the both end plates 51 and 52 with the fastening bolts 53 is performed by a cam-like projecting portion 54 that protrudes from the periphery of the both end plates 51 and 52 to the outer periphery, and the cam-like projecting portion 54 of the second end plate 52 will be described later. It functions as a cam for operating the pump 8 to be operated.

  The laminated metal plate 31 of the stator 3 plays a role for fixing the first end plate 51 and the second end plate 52 with a constant interval.

  The first end plate 51 and the second end plate 52 are provided with bearings 58 and 58 inside the center, respectively, and both ends of the rotating shaft 41 of the rotor 4 are supported by both bearings 58 and 58.

  A boss 56 projects from the center outer side of the first end plate 51, and a fixing support shaft 57 projects outwardly through the boss 56. An external screw 57b is formed on the fixing support shaft 57. Reference numeral 59 denotes a vent hole formed in the first end plate 51, which communicates the interior and exterior of the motor housing 5 with the outside air as the pump 8 described later operates to exhaust the air in the motor housing 5. Is supplied to the motor 9 to cool the motor 9. A tube (not shown) is connected to the vent hole 59, and the other end of the tube is fixed at a position where it is difficult for water of the electric assist bicycle 1 to enter the tube.

  A speed reduction mechanism that decelerates the rotation of the rotor 4 and transmits it to the hub 7 is provided outside the second end plate 52.

  The speed reduction mechanism of the embodiment is a planetary gear speed reduction mechanism 6.

  The planetary gear support frame 61 of the planetary gear speed reduction mechanism 6 has three cylindrical leg portions 62 projecting from the second end plate 52 at equal intervals in the circumferential direction. The end plate 52 is fixed to the second end plate 52 by a bolt 63 passing through the leg portion 62.

  Three support shafts 64 are suspended at equal intervals in the circumferential direction of the second end plate 52 between the second end plate 52 and the planetary gear support frame 61, and the planetary gear 65 can be rotated by each support shaft 64. To support.

  The planetary gear 65 is coaxially formed with a large gear 65a on the second end plate 52 side and a small gear 65b on the opposite side.

  The large gear 65 a of the planetary gear 65 meshes with a sun gear 60 formed at the end of the rotating shaft 41 of the rotor 4. The small gear 65b of the planetary gear 65 meshes with an internal tooth 66a on the cover plate 72 of the hub 7 described later.

  A boss 67 is formed on the inner surface of the central portion of the planetary gear support frame 61, and a fixing support shaft 57a projects outwardly through the center of the boss 67. An external screw 57b is formed on the fixing support shaft 57a.

  The hub 7 is configured by a substantially cup-shaped hub main body 71 having an opening at the center of the bottom surface and opening the entire opposite side, and a lid plate 72 covering the entire opening.

  The hub main body 71 covers the motor housing 5 and the planetary gear speed reduction mechanism 6, and a bearing 73 is interposed between the bottom opening 70 and the boss 56 on the first end plate 51 of the motor housing 5. On the inner surface of the hub main body 71, a ring body 66 is screwed and fixed concentrically with the fixing support shaft 57, and on the inner surface of the ring body 66, an internal tooth 66a with which the planetary gear 65 is engaged is formed.

  The fixing support shaft 57a on the planetary gear support frame 61 passes through the hub main body 71 and protrudes to the outside. A bearing 75 is interposed between the hub main body 71 and the fixing support shaft 57a.

  On both sides of the outer peripheral surface of the hub main body 71, a peripheral wall 74 protrudes around the hub main body 71, and spoke attachment holes 74a are regularly opened in the circumferential direction on the peripheral wall 74.

  The cover plate 72 covers the opening of the hub main body 71 and is fixed to the hub main body 71 by a plurality of bolts 76.

  A pump 8 is fixed to the hub main body 71 and is disposed opposite to the position where the cam-like projecting portion 54 of the second end plate 52 is formed, and the second end plate 52 as the hub 7 rotates. The cam-like projecting portion 54 is operated to discharge air in the hub 7.

  In FIG. 2, the rotation shaft 41 of the rotor 4, the fixing support shaft 57 on the first end plate 51 of the motor housing 5, and the fixing support shaft 57 a penetrating the lid plate 72 of the hub 7 are aligned. .

  Further, when both the fixing support shafts 57 and 57a are fixed to the front fork 12 of the bicycle with screws, in FIG. 2, the left slanted hatched portion is a fixed portion, and the right slanted hatched portion is a rotating portion.

  However, if a load of a certain value or more is applied to the depression of the bicycle pedal 18, current is supplied from the battery 17 to the winding 32 of the stator 3, and the rotor 4 rotates.

  As the rotor 4 rotates, the sun gear 60 at the tip of the rotating shaft 41 also rotates, and the planetary gear 65 rotates at a fixed position. The rotation of the planetary gear 65 is decelerated and transmitted to the hub 7 via the internal teeth 66a, and the front wheel 11 is driven to rotate.

  With the rotation of the hub 7, the pump 8 discharges air in the hub 7, so that outside air is supplied from the vent hole 59 toward the motor 5, and the motor 5 is cooled to prevent overheating of the motor 5.

  By the electric rotation of the rotor 4, it is possible to reduce the stepping force of the pedal 18 and run the bicycle. When the winding 32 is energized, the winding 32 generates heat, and the stator 3 has heat. However, since there is no cylindrical wall of the motor housing 5 that hinders heat dissipation of the stator 3 as in the prior art, even if the stator 3 is heated, the motor housing is opened from the opening between the pair of end plates 51 and 52 that sandwich the stator 3. 5 can be directly radiated to the outside. For this reason, it is possible to prevent the winding 32 from being overheated without containing the coolant in the hub 7 as in the prior art.

  Further, the cooling of the stator 3 is further promoted by the outside air supplied from the vent hole 59 toward the motor 5, and overheating of the winding 32 can be reliably prevented.

  The cylinder wall of the motor housing 5 can be omitted, and the labor for accommodating the coolant is not required, so that the manufacturing cost can be reduced. Further, the omission of the cylindrical wall and the coolant can contribute to weight reduction.

  Further, since the outer diameter of the stator 3 can be increased by the amount that the cylindrical wall does not exist, the rotational power can be increased.

  In the above embodiment, if the laminated metal plate 31 of the stator 3 has a large or small thickness in the circumferential direction, the parallelism of the both end plates 51 and 52 is distorted. Due to this deviation, a bending force acts on the rotating shaft 41 of the rotor 4 that is supported by the bearings 58 and 58 on the end plates 51 and 52 of both end plates, thereby hindering smooth rotation of the rotor 4. . Therefore, originally, as in the present invention, the laminated metal plate 31 of the stator 3 is sandwiched between the pair of end plates 51 and 52, and both end plates 51, 52 are arranged so that screw thrust is applied in the lamination direction of the laminated metal plate 31. It is problematic to fix 52 with the fastening bolt 53.

  However, in the embodiment, as described above, the laminated metal plate 31 of the stator 3 is laminated by shifting a plurality of unit bodies 31c obtained by laminating the unit number of punched metal plates 31a by a predetermined angle. The circumferential thickness of the plate 31 is made as uniform as possible. Therefore, the parallelism between the first end plate 51 and the second end plate 52 can be improved even if both the end plates 51 and 52 are tightened and fixed with the tightening bolts 53 so that a screw thrust is applied in the stacking direction of the stacked metal plates 31. High accuracy can be achieved.

  Therefore, the parallelism of the bearings 58 and 58 that support both ends of the rotating shaft 41 of the rotor 4 can be increased, and the rotor 4 can be smoothly rotated.

  The above description of the embodiments is for explaining the present invention, and should not be construed as limiting the invention described in the claims or reducing the scope thereof. In addition, the configuration of each part of the present invention is not limited to the above embodiment, and various modifications can be made within the technical scope described in the claims.

2 Hub unit 3 Stator 4 Rotor 5 Motor housing 6 Planetary gear reduction mechanism 7 Hub 8 Pump 9 Motor
31 laminated metal sheet
59 Vent

Claims (5)

A hub unit for an electric wheel having a motor including a stator and a rotor, and a hub that is housed in the motor and is driven to rotate by rotation of the rotor.
The hub is provided with a fixing support shaft that protrudes in a fixed state with respect to the motor housing on the rotation center axis of the hub and protrudes to the outside of the hub, and has a ventilation hole for taking in outside air in the vicinity of the fixing support shaft. Forming and connecting a tube to the vent hole, extending the end of the tube to a place where water of the electric vehicle does not enter, and with the rotation of the hub, outside air is introduced into the hub through the vent hole An electric wheel hub unit comprising motor cooling means for cooling an intake motor.   2. The hub unit for an electric wheel according to claim 1, wherein the hub is formed with a pump mechanism which is operated by a protrusion formed on the outer periphery of the motor housing and discharges air in the hub.   2. The stator according to claim 1, wherein a pair of end plates arranged opposite to each other with a laminated metal plate interposed therebetween are bolted together, and the outer peripheral surface of the stator opens between the end plates to the inner surface of the hub. The hub unit for electric wheels as described.   The hub unit for an electric wheel according to claim 1, wherein a planetary gear mechanism that is operated by rotation of the rotor is accommodated in the hub, and inner teeth that mesh with the planetary gear of the planetary gear mechanism are provided on the inner surface of the hub.   5. A vehicle using the electric wheel hub unit according to claim 1 as a wheel hub.

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