TW201836911A - Power unit for electric vehicle - Google Patents

Abstract

In a power unit for an electric vehicle, a speed-reduction mechanism part (R) includes: a speed-reduction sun gear (51) that is rotated by a motor (M); a first gear (52a) meshing with the speed-reduction sun gear; a speed-reduction carrier (53) rotatably supporting a second gear (52b) aligned coaxially with the first gear; a first speed-reduction ring gear (54) fitted into an opening end portion (31a) of a motor case (31) and meshing with the first gear; and a second speed-reduction ring gear (55) provided at a one end wall portion (He) of a hub case (H) and meshing with the second gear. A bearing (B7) is interposed between the first speed-reduction ring gear (54) and the hub case (H), the first speed-reduction ring gear (54) being rotatably supported on the hub case (H) via the bearing (B7). Accordingly, while securing a high speed-reduction ratio at the speed-reduction mechanism part that transmits a drive force of the motor to the hub case, the first speed-reduction ring gear on the motor case side can be supported stably and firmly on the hub case.

Description

Power unit for electric vehicles

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle, and more particularly to a power unit for an electric vehicle, which is a speed reduction mechanism that decelerates and transmits a driving force of a motor to a hub casing, and is arranged in the axial direction and housed in the wheel. A hub shell, wherein the hub shell of the wheel is rotatably supported on the hub axle.

In the present invention and the present specification, the "axial direction" and the "diameter direction" mean the axial direction and the radial direction with the hub axis as a reference, respectively.

BACKGROUND OF THE INVENTION As a power unit for an electric vehicle, there is known a unit including a reduction sun gear, a reduction bracket, and a reduction ring gear that is rotationally driven by a motor to a speed reduction mechanism portion including a planetary gear mechanism. The reduction bracket is rotatably supported by a reduction planetary gear that meshes with the reduction sun gear, and the reduction ring gear is fixed to an open end of the motor casing (the first outer casing member 32) constituting the bottom cylinder and meshes with the deceleration planet The gear is fixed to and supported by the closed end of the motor casing (see, for example, Patent Document 1 below). Prior technical literature

Patent Document Patent Document 1: Japanese Patent No. 5300830

SUMMARY OF THE INVENTION Problems to be Solved by the Invention However, in the above-described conventional structure, on the free end portion (i.e., the open end portion) of the motor casing which is further away from the support point (i.e., the closed end portion) of the hub axle in the axial direction The reduction ring gear is fixed, and is a support form in which the reduction ring gear is supported in a cantilever shape with respect to the hub axle. Therefore, there is a concern that the reduction ring gear is easily vibrated due to the rotational vibration of the motor or the like, and the tooth bearing failure or the partial wear of the meshing portion of the reduction ring gear and the reduction planetary gear is generated by the vibration. Problems such as noise caused by meshing.

The present invention has been made in view of the above circumstances, and an object of the invention is to provide a reduction ratio that ensures a high reduction ratio in a speed reduction mechanism portion and that can stably and securely support a reduction ring gear to a hub casing. A power unit for an electric vehicle that can solve the above problems. Means to solve the problem

In order to achieve the above object, a first aspect of the present invention provides a power unit for an electric vehicle, in which a one end wall portion and a other end wall portion of a hub casing of a wheel are rotatably supported by a hub axle, and a motor, And a speed reduction mechanism that decelerates the driving force of the motor and transmits the same to the hub casing in the axial direction, and the motor has an end portion that is open and faces the one end wall portion of the hub casing. a bottom cylindrical motor casing fixed to the other end of the bottom wall of the motor casing and supported by the hub axle, wherein the speed reduction mechanism portion includes a reduction sun gear that is rotationally driven by the motor, and a speed reduction bracket that rotates freely Supporting the first gear and the second gear, wherein the first gear meshes with the reduction sun gear, the second gear is coaxially arranged with respect to the first gear; and the first reduction ring gear is embedded in the motor casing The one end portion is meshed with the first gear; and the second reduction ring gear is disposed on the hub casing and meshed with the second gear Wheel, and between the first reduction ring gear and the hub shell, so that the plug with the first reduction ring gear is rotatably supported by the hub bearing housing.

According to a second aspect of the present invention, in addition to the first feature, the side wall portions of the first and second gears are sandwiched in the axial direction of the deceleration bracket, and are rotatably supported by the hub. axis.

According to a third aspect of the present invention, in addition to the first or second feature, the first reduction ring gear integrally has a ring gear extension portion that is axially larger than the aforementioned motor housing. One end portion extends outside the motor casing, and an outer circumferential surface or an inner circumferential surface of the extending portion is a mounting surface on the first reduction ring gear side of the bearing. Effect of the invention

According to the first aspect of the present invention, the planetary gear of the speed reduction mechanism portion including the planetary gear mechanism has the first and second gears that are coaxial, and the first reduction ring gear that meshes with the first gear is embedded in the bottom. One end portion (open end portion) of the cylindrical motor casing is provided with a second reduction ring gear that meshes with the second gear in the hub casing, and is inserted between the first reduction ring gear and the hub casing to make the first Since the reduction ring gear is rotatably supported by the bearing of the hub casing, it is possible to ensure a high reduction ratio in the speed reduction mechanism portion and to improve the support rigidity of the first and second reduction ring gears.

In particular, the first reduction ring gear is fixed to the free end portion (one end portion) of the motor casing and is in a cantilever support configuration with respect to the hub axle. However, the first reduction ring gear is rotatably transmitted through the bearing. Supported by the hub casing, the first reduction ring gear is substantially in the form of a double arm support, and the support is stabilized and effective for preventing the shaft from being deviated. With this configuration, even if the rotational vibration of the motor is directly transmitted to the first reduction ring gear, the vibration of the first reduction ring gear can be effectively suppressed. Therefore, the toothing of the meshing portion between the first reduction ring gear and the reduction planetary gear can be made good. And the durability is improved, and the generation of noise from the meshing portion can be reduced.

In addition, according to the second feature, the two side wall portions of the first and second gears can be rotatably supported by the deceleration bracket in the axial direction, so that it can be used in the hub shaft. The open end (one end portion) of the motor casing is supported by the first reduction ring gear and the bearing on the hub outer casing side to create a space around the hub axle, and the support bracket can be long in the axial direction of the reduction bracket ( Span) to support the arms. Thereby, it is possible to achieve both miniaturization of the power unit and stable support of the deceleration bracket.

Further, in particular, according to the third feature, since the first reduction ring gear integrally has a ring gear extension portion, the ring gear extension portion extends outward in the axial direction from the one end portion of the motor casing toward the outside of the motor casing, and The outer peripheral surface or the inner peripheral surface of the ring gear extending portion is a mounting surface on the first deceleration ring gear side of the bearing. Therefore, even if the diameter of the motor casing is not particularly increased, the bearing diameter can be easily ensured and It contributes to further miniaturization of the power unit.

MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described based on additional drawings. [First Embodiment]

First, a first embodiment of a power unit for an electric vehicle according to the present invention will be described with reference to Figs. 1 to 5 .

The electric bicycle power unit U, which is an example of a power unit for an electric vehicle, includes a single hub axle 11 that functions as an axle of an electric bicycle, for example, an axle of a rear wheel, and a hub casing H that is rotatably supported for use as a rear a hub shaft 11 that functions as a hub portion of the wheel; the speed change mechanism portion T is housed in the hub housing H, and the pedaling force input from the pedal is variably transmitted to the hub housing H; and the motor drive system MD is in the hub housing H The inside is disposed adjacent to the shifting mechanism portion T in the axial direction, and the hub housing H can be electrically driven.

In the present embodiment, the hub axle 11 is formed by forging or machining a shaft as a unitary body. Although not shown, both end portions of the hub axle 11 are inserted and supported on the left and right rear forks in the same manner as conventional electric bicycles, and are coupled and fixed by fastening means such as nuts.

The hub case H includes a bottomed cylindrical case body Hm having one end open and integrally having an end wall portion Hmb at the other end, and a ring-shaped end portion Hme detachably coupled to the open end portion Hme of the hub case body Hm. End wall member He.

In the present embodiment, the end wall member He is divided into, for example, an annular first end wall member half body He1 and a second end wall member half body He2 in order to facilitate the manufacturing process, wherein the second wall member He is divided into two, for example, an annular first end wall member half body He1 and a second end wall member half body He2. The end wall member half body He2 is formed so as to be fitted around the first end wall member half body He1 and fixed to the outer peripheral portion of the first end wall member half body He1. The outer peripheral portion of the second end wall member half body He2 is an end portion Hme into which the hub housing main body Hm is inserted and fitted. The first and second end wall member halves He1 and He2 may be joined to each other by a suitable joining means such as press fitting, welding, screwing, or the like, or may be integrally formed.

The means for joining the end wall member He to the hub casing body Hm is, in the present embodiment, penetrated through the end wall member He (more specifically, the second end wall member half body He2) and is screwed into one end portion of the hub casing body Hm. The plurality of bolts 14 of the outer peripheral boss portion of the Hme are formed, but other suitable joining means such as press fitting may be employed. A spoke (not shown) of the rear wheel is fixed to the outer peripheral portion of the hub casing body Hm.

The hub casing H is rotatably supported by the hub axle 11 by transmitting the end wall portion Hmb through the hub support first bearing B1 and the end wall member He through the hub support second bearing B2. More specifically, the support structure is such that the hub support ring 15r is supported by the support nut 15n on the hub shaft 11, and the hub support ring 15r holds the first support for the hub between the inner circumference of the end wall portion Hmb. Bearing B1. The support nut 15n is configured to fit and support the inner peripheral portion of the hub support ring 15r, and is screwed to the hub axle 11, and the screwing position thereof is fixed by the lock nut 16. In the assembly step of supporting the end wall portion Hmb to the hub axle 11 through the first support B1 for hub support and the hub support ring 15r, the preload of the first bearing B1 for hub support can be adjusted by the support nut 15n. .

Further, the hub shaft 11 is a shift bracket 22 that holds the speed change mechanism portion T of the hub support second bearing B2 between the inner wall member He (more specifically, the first end wall member half body He1). It is rotatably supported by the bracket supporting bearing B3 as will be described later.

Further, the first and second bearings B1 and B2 for the hub support are disposed on the inner side in the radial direction of the outer diameter of the motor drive system MD (the motor M) as viewed from the projection plane orthogonal to the hub axle 11.

Next, an example of the speed change mechanism portion T will be described. The speed change mechanism portion T includes a driven sprocket 21 as an input member for inputting a pedaling force from the pedal, and the shift bracket 22 is integrally coupled to the driven sprocket 21 and rotatable on the hub axle 11; 23, rotatably fitted and supported on the outer circumference of the hub axle 11; the shifting mechanism S is interposed between the shift sun gear 23 and the hub axle 11, and can be used to switch the shift sun gear 23 to the hub axle 11 to be fixed a switching device of a state and a rotatable state; a plurality of shifting planetary gears 24 rotatably supported by the shifting bracket 22 and meshing with the shifting sun gear 23; the shifting ring gear 25 meshing with the shifting planetary gear 24; the one-way transmission mechanism OT, in the fixed state of the shift sun gear 23 to the hub axle 11, the pedaling force input to the shift bracket 22 is transmitted to the end wall member He of the hub casing H through the shifting planetary gear 24 and the shift ring gear 25, In the rotatable state, the pedaling force is transmitted to the end wall member He without passing through the shifting planetary gear 24.

The pedal sprocket 21 transmits the pedaling force of the pedal as a rotational force through a chain transmission mechanism including the driven sprocket 21, transmits the rotational force to the shift bracket 22, and transmits the torque to the hub casing H through the shifting mechanism portion T. Drive the rear wheel.

In the present embodiment, the shift bracket 22 is configured to be divided into a cylindrical first bracket half 22A and a disc-shaped second bracket half 22B, for example, in order to facilitate the manufacturing process. The one end portion 22Aa of the first bracket half 22A integrally has a bracket shaft supporting wall portion that supports both end portions of the bracket shaft 27, whereby the one end portion 22Aa can pass through the bracket shaft 27, the shifting planetary gear 24, and the shifting sun gear 23 It is supported by the hub axle 11. On the other hand, on the inner circumference of the other end portion 22Ab of the first bracket half 22A, the outer circumference of the stopper ring 17 that is not rotatably fitted (for example, pressed) with respect to the outer circumference of the hub axle 11 The bracket supporting bearing B3 is inserted, and the other end portion 22Ab is rotatably supported by the hub axle 11 through the bracket supporting bearing B3.

In the outer periphery of the intermediate portion of the first bracket half 22A in the axial direction, the inner peripheral portion of the second bracket half 22B is fitted and fixed by press fitting. Further, on the outer circumference of the first holder half 22A, spline fitting is performed on each inner peripheral portion of the driven sprocket 21 adjacent to the second holder half 22B, and the washer 28 and the snap ring 29 are provided. Come fixed.

Further, as a fixing means of the driven sprocket 21, other suitable fixing means may be employed instead of the snap ring 29, such as a nut. Furthermore, the first and second holder halves 22A and 22B may be combined with each other by other suitable bonding means such as welding, screwing, bonding, or the like, or may be integrally formed.

Further, the inner side surface in the axial direction of the outer peripheral portion of the second bracket half 22B is integrally protruded from the cylindrical bracket extending portion 22Ba extending toward the motor M side, and the bracket extending portion 22Ba is formed to have a diameter ratio of the shifting ring. The gear 25 has a larger cylindrical shape. Further, the second bearing B2 for hub support described above is inserted between the outer circumferential surface of the bracket extending portion 22Ba and the opposing circumferential surface of the inner circumference of the end wall member He (more specifically, the second end wall member half body He2). .

The shifting ring gear 25 integrally has a ring gear body portion 25m having an internal tooth 25mg that meshes with the shifting planetary gear 24, and a ring gear extending portion 25a that is a ring gear body portion 25m from the ring gear body portion 25m. It extends in the axial direction toward the side opposite to the motor drive system MD, and the ring gear extension 25a is surrounded by the bracket extension 22Ba in a concentric manner. A shift ring gear support bearing B4 is inserted between the inner circumferential surface of the ring gear extending portion 25a and the opposing circumferential surface of the outer periphery of the shift bracket 22 (more specifically, the one end portion 22Aa of the first bracket half 22A).

Next, an example of the one-way transmission mechanism OT will be described. The one-way transmission mechanism OT includes a first one-way clutch C1 and a second one-way clutch C1 which are provided between the shift ring gear 25 and the end wall member He, and can be provided only from the shift ring gear 25 The second one-way clutch C2 is disposed between the shift bracket 22 and the shift ring gear 25 at a position shifted from the first one-way clutch C1 in the axial direction, and is transmitted to the end wall member He side. Power transmission is performed from the shift bracket 22 to the shift ring gear 25 side.

In the present embodiment, the first one-way clutch C1 is interposed between the outer circumference of the ring gear main body portion 25m and the opposing circumferential surface of the inner circumferential seat portion 63 of the first end wall member half body He1. The second one-way clutch C2 is interposed between the inner circumference of the bracket extension portion 22Ba and the opposing circumferential surface of the outer circumference of the ring gear extension portion 25a.

In this way, at least a part of the second one-way clutch C2 (in the present embodiment, most of them) is at the same position in the axial direction as at least a part (in the present embodiment) of the variable-speed ring gear supporting bearing B4. , that is, a configuration that overlaps in the radial direction. Further, at least a part of the second one-way clutch C2 (all in the present embodiment) is at the same position in the axial direction as at least a part of the second bearing B2 for the hub support (in the present embodiment). , that is, a configuration that overlaps in the radial direction.

The first and second one-way clutches C1 and C2 are clutches having the same structure as the conventional one-way clutch structure. Although not shown, the first and second one-way clutches C1 and C2 include a plurality of engaging grooves and engaging members (for example, ratchet claws). And a spring, the plurality of engagement grooves being provided at intervals on a circumferential surface of one of an inner race and an outer race of the outer race, the snap is The pivoting support is pivotally supported on one of the other circumferential surfaces thereof and the engagement groove can be engaged and disengaged, and the spring can move the respective engaging bullets in the locking direction of the engaging groove. Further, the inner race and the outer race may be separately and independently formed from the members in which the first and second one-way clutches C1 and C2 are provided, and may be added later or integrally formed.

Further, in the present embodiment, the outer peripheral surfaces of the ring gear main body portion 25m and the ring gear extending portion 25a which are the mounting faces of the first and second one-way clutches C1 and C2 in the shift ring gear 25 have the same diameter. Further, the inner circumferential surface of the inner circumferential boss portion 63 of the first end wall member half body He1 serving as the mounting surface of the first one-way clutch C1 in the end wall member He and the second one-way direction in the shift bracket 22 The inner peripheral surface of the bracket extension portion 22Ba of the mounting surface of the clutch C2 is also the same diameter. Therefore, the first and second one-way clutches C1 and C2 can be used with the same specifications, and the cost savings due to the commonality of the components can be achieved. However, since the first and second one-way clutches C1 and C2 are opposite to each other in the power transmission direction, the direction of the circumferential direction of the engaging member and the engaging groove in the first one-way clutch C1 is set to be the second one. The circumferential direction of the clutch C2 is opposite to each other.

Next, an example of the shift mechanism S will be described mainly with reference to Figs. 3 to 5 .

The shift mechanism S includes a plurality of ratchet grooves 23a that are recessed in the circumferential direction on the inner circumferential surface of the shift sun gear 23, and a plurality of claw receiving holes 11a are formed on the outer circumferential surface of the hub shaft 11 in the circumferential direction. The ratchet pawl 41 is slidably fitted and supported by the pawl receiving hole 11a, and the claw distal end portion 41as of the claw main body portion 41a can be engaged with the ratchet groove 23a by the undulating swing. The ring spring 42 is fitted to the outer circumference of the hub axle 11 in an elastic contraction state for imparting potential energy to the ratchet pawl 41 toward the engagement direction of the ratchet groove 23a (that is, the rising direction of the ratchet pawl 41), and The outer circumference of the intermediate portion 41m of the ratchet pawl 41 is crimped; the operation roller 43 has a concave portion 431i on the inner circumferential surface that allows the claw distal end portion 41bs of the ratchet pawl 41 to be infested, and is set at a predetermined locking position. The outer circumference of the hub axle 11 is fitted and supported by the unlocked position; the return spring 44 is rotated by the side of the operating roller 43 toward the unlocked position (ie, the position of FIG. 5(B)). The movable end and the potential energy cause the movable end 44a to be locked to the twist of the operating roller 43 The spring receiving ring 45 is rotatably fitted (for example, pressed in) with respect to the outer circumference of the hub axle 11 and is locked by the fixed end 44b of the return spring 44; and the fixing ring 46 is for preventing the roller from being operated. It is disposed adjacent to the outer end of the operation drum 43 and is fitted (for example, pressed in) so as not to relatively rotate the outer circumference of the hub axle 11.

The operation roller 43 is divided by the first and second roller halves 431 and 432 which are coupled to each other (for example, meshing engagement) so as not to be rotatable relative to each other. A plurality of operation lever portions 432t that are arranged at intervals in the circumferential direction of the operation roller 43 are integrally extended from the outer end of the second roller half body 432 toward the outer side in the axial direction. Further, each of the operation lever portions 432t is loosely inserted through the insertion groove and protrudes toward the outer surface of the shift bracket 22, and the insertion grooves are recessed in the inner circumferential surfaces of the fixed ring 46 and the brake ring 17, respectively. The operation lever portion 432t is formed so as to be rotatable between the lock position and the unlock position by the operation unit CU, which will be described later.

Thus, when the operation roller 43 is held in the unlocked position shown in FIG. 5(B), the claw body portion 41a of the ratchet pawl 41 interlocked with the operation roller 43 can be placed against the imparting force of the ring spring 42 and The state of being separated from the ratchet groove 23a (that is, the state of being stored in the claw accommodation hole 11a). Thereby, the shift sun gear 23 is rotatable with respect to the hub axle 11, and the shifting planetary gear 24 is also rotatable similarly to the shift sun gear 23. Therefore, the rotation of the shifting bracket 22 in response to the pedaling force can be directly transmitted to the end wall member He via the second one-way clutch C2, the shifting ring gear 25, and the first one-way clutch C1 (ie, the transmission planetary gear 24 is not transmitted). And then to the hub shell H. In this manner, the first speed is established in the speed change mechanism portion T.

On the other hand, when the operation roller 43 is held in the lock position shown in FIG. 4(B) against the return spring 44, the ratchet pawl 41 released by the operation roller 43 is given by the ring spring 42. Since the potential capability is switched to the locked state of the ratchet groove 23a, the shift sun gear 23 is connected to the hub axle 11, that is, the fixed state, and the rotation is impossible. Thereby, since the shifting planetary gear 24 meshing with the shift sun gear 23 revolves around the hub axle 11 and rotates around the shift bracket shaft 27 with the rotation of the shift bracket 22, the rotation of the shift bracket 22 is borrowed. The speed change planetary gear 24 is idling and transmitted to the shift ring gear 25, and the rotation of the idle shift ring gear 25 is transmitted to the end wall member He via the second one-way clutch C2 and then to the hub shell H . In this way, the second speed after the acceleration is higher than the first speed is established in the speed change mechanism portion T.

Further, on the outer circumference of the hub axle 11, the unit casing CUc of the operation unit CU for switching the shift mechanism S is by the nut 18 at a position adjacent to the outer side in the axial direction of the shift bracket 22. fixed. In the unit casing CUc, an actuating plate 71 is rotatably received and supported, and the actuating plate 71 is engaged with the operating lever portion 432t of the shifting mechanism S and is capable of rotating the operating drum 43.

An operation lever 72 that protrudes outward from the unit casing CUc and that can rotate the actuation plate 71 is coupled to the actuation plate 71, and the operation lever 72 can be remotely operated from the outside. Thereby, the flight attendant can operate the operation unit CU in the manner of the remote control operation, and selectively switches the operation roller 43 of the shift mechanism S to any one of the lock position and the unlock position according to the operation input, whereby the operation can be arbitrarily performed The above-described shifting operation of the first speed and the second speed is performed.

Next, an example of the motor drive system MD will be described. The motor drive system MD includes an electric motor M and a speed reduction mechanism portion R that decelerates the drive force of the motor M and transmits it to the end wall member He of the hub casing H.

The motor M includes, for example, a motor casing 31 having a bottomed cylindrical shape in which the one end portion 31a is opened and a bottom wall member He, and a stator 32 fixed to the inner circumferential surface of the main body of the motor casing 31, and disposed on the radially inner side of the stator 32. The rotor 33 to which the permanent magnet is attached and the cylindrical motor shaft 34 that fixes the rotor 33 to the outer peripheral portion. The motor shaft 34 is rotatably fitted and supported by the pair of motor shaft supporting first and second bearings B5 and B5' and supported on the outer circumference of the hub axle 11.

The inner peripheral portion of the end wall portion 31b of the bottom wall of the motor casing 31 which is formed in a convex shape is, for example, fitted and fixed (in the present embodiment, spline-pressed) to the outer periphery of the boss member 35, wherein the boss member 35 is fitted (fixed in this embodiment) to the outer circumference of the hub axle 11. Further, the inner peripheral portion of the end wall portion 31b may be fixed to the outer circumference of the hub axle 11 by a fixing means different from the present embodiment (for example, a combination of a spline and a snap ring, or screwing).

Further, an electronic control unit ECU that performs energization control of the motor M (more specifically, the coil portion of the stator 32) may be attached to the outer surface of the end wall portion 31b of the motor casing 31. The wiring extending from the electronic control unit ECU is pulled out to the outside through the through hole of the hub support ring 15r. Furthermore, the wiring can be connected to a pedaling force detecting device, a vehicle battery, or the like, which is not shown.

Next, an example of the speed reduction mechanism portion R will be described. The speed reduction mechanism unit R includes a reduction sun gear 51 that is rotationally driven by the motor M, a first gear 52a that meshes with the reduction sun gear 51, and a second gear that is coaxially arranged with respect to the first gear 52a. The plurality of reduction planetary gears 52 that are integrally coupled to each other, the deceleration bracket 53 that rotatably supports the reduction planetary gear 52, and the first deceleration that is engaged with the one end portion 31a of the motor casing 31 and meshes with the first gear 52a. The ring gear 54 and the second reduction ring gear 55 meshing with the second gear 52b.

The reduction sun gear 51 is press-fitted and fixed to the outer circumference of the hub axle 11 adjacent to the first bearing B6 for supporting the reduction bracket described later. Further, as the fixing means of the reduction sun gear 51, a fixing means different from the present embodiment, for example, welding, splicing, splicing, spline fitting, and snap ring may be used.

The speed reduction bracket 53 includes a speed reduction bracket shaft 56, a first bracket half body 53a, and a second bracket half body 53b. The speed reduction bracket shaft 56 rotatably supports and supports the respective reduction planetary gears 52. The first bracket half body 53a has The first side wall portion s1 of one end portion of the speed reduction bracket shaft 56 is fixed, and the second holder half body 53b has the other end portion that fixes the reduction planetary gear 52 between the first side wall portion s1 and fixes the other end portion of the speed reduction bracket shaft 56. 2 side wall portion s2. The first holder half 53a integrally has a plurality of connecting arms 53au, and the front end portion of the connecting arm portion 53au is fixed to the second holder half 53b.

The first side wall portion s1 is rotatably supported by the motor shaft 34 (and rotatably supported by the hub shaft 11 through the motor shaft 34) through the first bearing B6 for supporting the reduction bracket, wherein the first bearing B6 for supporting the reduction bracket It is inserted between the inner circumference of the first holder half body 53a and the opposing circumferential surface of the motor shaft 34. On the other hand, the second side wall portion s2 is rotatably supported by the hub axle 11 through the second bearing B6' for supporting the reduction bracket, and the second bearing B6' for supporting the reduction bracket is inserted in the second bracket half. The inner circumference of 53b and the opposing circumferential surface of the hub axle 11. Further, a fixing ring 57 is fitted to the outer circumference of the hub axle 11 (for example, press-fitted), and the fixing ring 57 is engaged with the inner race of the second bearing B6' for the reduction bracket support to press the second bearing B6. '(The deceleration bracket 53 is followed) is held on the hub axle 11.

The first reduction ring gear 54 integrally has a ring gear main body portion 54m having inner teeth 54mg that meshes with the first gear 52a, and a ring gear extension portion 54a that faces the motor housing 31 in the axial direction from the ring gear main body portion 54m. Extend outside.

However, the outer end wall member He, in particular, in the axially inner side surface of the second end wall member half body He2, integrally protrudes in a cylindrical shape extending inward in the axial direction and fitted to the inner circumference of the hub casing body Hm. In the outer peripheral portion of the inner side surface of the second end wall member half body He2 in the axial direction, the outer side extending portion 61 is integrally provided with a cylindrical shape that extends inward in the axial direction and is concentrically surrounded by the outer extending portion 61. Inner extension 62. Further, the ring gear extending portion 54a of the first reduction ring gear 54 is an annular space defined by the outer extending portion 61 and the inner extending portion 62.

Further, between the inner circumference of the ring gear extending portion 54a and the outer circumference of the inner extending portion 62, a first reduction ring gear supporting bearing B7 is inserted, and the first reduction ring gear supporting bearing B7 is transmitted through the hub casing H ( More specifically, the second end wall member half body He2) rotatably supports the first reduction ring gear 54. Therefore, the inner circumferential surface of the ring gear extending portion 54a serves as a mounting surface on the side of the first reduction ring gear 54 of the bearing B7.

As described above, when the rotation of the reduction sun gear 51 driven by the motor M is transmitted to the first gear 52a of the reduction planetary gear 52, since the first reduction ring gear 54 is fixed to the motor casing 31, it is rotatably supported for deceleration. The reduction planetary gear 52 of the bracket 53 revolves around the reduction bracket shaft 56 while revolving around the hub axle 11. In addition, the rotation and rotation of the reduction planetary gear 52 are transmitted from the second gear 52b to the second reduction ring gear 55, and the rotation of the drive electric motor 4 can be transmitted to the higher reduction ratio as will be described later. Hub housing H.

Next, the action of the first embodiment will be described. During the walking of the electric assist bicycle, the pedaling force of the pedal by the rider can be shifted in two stages (the first speed or the second speed) through the speed change mechanism unit T, and transmitted to the end wall member He and then Hub housing H.

For example, when the operation roller 43 of the shift mechanism S is in the unlocked position and the connection between the shift sun gear 23 and the hub axle 11 is released, the rotation of the shift bracket 22 is passed through the second one-way clutch C2 and the shift ring gear. 25. The first one-way clutch C1 is directly transmitted to the end wall member He. Thereby, the hub housing H of a part of the rear wheel rotates at the same number of rotations as the shift bracket 22.

On the other hand, when the operating roller 43 of the shifting mechanism S is in the locked position and the shifting sun gear 23 is fixed to the hub axle 11, the rotation of the shifting bracket 22 is accelerated by the shifting planetary gear 24 and the shifting ring gear 25 And communicated to the end wall member He. Thereby, the rotation of the hub shell H with respect to the shift bracket 22 is accelerated and rotated.

Further, since the second one-way clutch C2 is inserted between the shift bracket 22 and the shift ring gear 25, and the first one-way clutch C1 is inserted between the shift ring gear 25 and the end wall member He, For example, even when the pedal is rotated slowly and the rotation of the hub casing H is fast in the downhill slope, there is no case where the rotation of the hub casing H is transmitted to the pedal side.

Further, when the traveling load of the rear wheel is detected by the load detecting device (not shown) during the traveling of the power-assisted bicycle, the motor M is energized from the electronic control unit ECU, and is sufficiently supplied via the speed reducing mechanism unit R. The rotation of the motor shaft 34 is decelerated to be communicated to the end wall member He to the hub shell H. Thereby, since the driving force of the motor M can be used to assist the insufficient pedaling force, it is possible to travel without difficulty even if it is uphill, for example.

Further, in the speed change mechanism portion T of the present embodiment, the first one-way clutch C1 that is inserted between the end wall member He and the shift ring gear 25 is inserted between the shift ring gear 25 and the shift bracket 22. The second one-way clutch C2 is disposed in series on the shift ring gear 25 (more specifically, the outer peripheral surfaces of the shift ring gear main body 25m and the ring gear extending portion 25a) at positions shifted from each other in the axial direction, and is further inserted into the shifting ring gear 25 The hub-supporting second bearing B2 between the shift bracket 22 and the end wall member He is disposed so as to be in the same position as the majority of the second one-way clutch C2 in the axial direction (that is, overlap in the radial direction). And around the circumference of the second one-way clutch C2. With this configuration, the speed change mechanism portion T can be miniaturized in the axial direction compared to the conventional structure in which the first and second one-way clutches C1 and C2 and the second hub-supporting bearing B2 are arranged in the axial direction. Therefore, the miniaturization of the power unit U can be achieved in accordance with the degree of miniaturization.

Further, on the other hand, the first and second one-way clutches C1 and C2 are arranged in series on the shift ring gear 25 as described above, and on the other hand, the one end wall portion of the hub casing H, that is, the end wall member He is provided. The passive portion (more specifically, the inner extending portion 62 of the second end wall member half He2) from the motor drive system MD can be input. Thereby, the passive portion that receives the power from the end wall member He is the passive portion (the inner extending portion 62 of the second end wall member half He2) from which the power is supplied from the motor drive system MD and the power from the first one-way clutch C1. In the passive portion (the inner circumferential boss portion 63 of the first end wall member half body He1), it is possible to reduce the size and structure of the end wall member He, and it is possible to reduce the size of the power unit U.

Further, the shift ring gear 25 has a ring gear body portion 25m and a ring gear extending portion 25a having internal teeth 25mg that mesh with the shifting planetary gear 24, and the ring gear extending portion 25a is a ring gear body portion The 25m extends outward in the axial direction, and the second one-way clutch C2 can be inserted between the outer circumference of the ring gear extending portion 25a and the inner circumference of the bracket extending portion 22Ba. With this, even if the total axial width of the first and second one-way clutches C1 and C2 is longer than the tooth width of the shifting planetary gear 24, the two clutches C1 and C2 are adjacent to each other in the axial direction. Then, it can be arranged in-line on the shift ring gear 25 without difficulty.

Further, a shift ring gear support bearing B4 is inserted between the inner circumference of the ring gear extending portion 25a and the opposing circumferential surface of the shift bracket 22, and the shift ring gear support bearing B4 is disposed in the axial direction and 2 One-way clutch C2 is mostly in the same position. With this configuration, even if the shift ring gear 25 is arranged in the axial direction as the first and second one-way clutches C1 and C2 are arranged in the axial direction, the shift ring gear support bearing B4 can be transmitted through the shifting ring gear support bearing B4. Since it is supported by the shift bracket 22, the gear bearing of the shifting planetary gear 24 is also good, and the shifting planetary gear 24 can be smoothly and quietly rotated. Further, since the variable-speed ring gear supporting bearing B4 is partially overlapped with the ring gear extending portion 25a in the radial direction, the axial direction of the bearing B4 can be suppressed from being extended, so that the axial direction of the power unit U can be made small. Chemical.

Further, in the speed reduction mechanism portion R of the present embodiment, the reduction planetary gear 52 has the first and second gears 52a and 52b that are coaxially arranged, and the first reduction ring gear 54 that meshes with the first gear 52a is embedded in The one end portion 31a of the bottomed cylindrical motor casing 31 is provided with the second reduction ring gear 55 meshed with the second gear 52b at the end wall member He (more specifically, the inner end portion 62 of the second end wall member half body He2) In the inner circumference, the first reduction ring gear support bearing B7 is inserted between the first reduction ring gear 54 and the end wall member He (more specifically, the outer circumference of the inner extension portion 62). Thereby, the speed reduction mechanism portion R can secure a high reduction ratio, and the support rigidity of the first and second reduction ring gears 54, 55 for ensuring the reduction ratio can be sufficiently ensured by the end wall member He. .

In particular, the first reduction ring gear 54 is fixed to the one end portion 31a of the motor casing 31, that is, the free end portion (open end portion), and is in a cantilever support form with respect to the hub axle 11, but by this The ring gear extending portion 54a of the first reduction ring gear 54 is supported by the end wall member He through the first reduction ring gear support bearing B7, and the first reduction ring gear 54 is substantially in the form of a double arm support, thereby stabilizing the support. And it is effective for prevention of the axis deviation. Therefore, even if the rotational vibration of the motor M is directly transmitted to the first reduction ring gear 54, the vibration of the first reduction ring gear 54 can be suppressed as much as possible, so that the first reduction ring gear 54 and the reduction planetary gear 52 can be more specifically The meshing portion of the first gear 52a) has good teeth and improves durability, and it is also possible to reduce the generation of noise from the meshing portion.

Further, by passing the first reduction ring gear 54 and the first reduction ring gear support bearing B7 as described above, the one end portion 31a of the motor casing 31 is supported on the hub casing H side, so that it is unnecessary to make one end portion of the motor casing 31 The 31a side is supported by the hub axle 11, and in this case, a margin of space is generated around the hub axle 11. In the present embodiment, the two side wall portions s1 and s2 (the first and second bracket halves 53a and 53b) of the deceleration bracket 53 are transmitted through the deceleration bracket supporting first and second bearings B6. B6' is supported on the hub axle 11, so that the deceleration bracket 53 having a wide width in the axial direction can be supported by the support with a long span in the axial direction. Thereby, it is possible to reduce the size of the power unit U and to achieve stable support of the deceleration bracket 53.

Further, the first reduction ring gear 54 of the present embodiment integrally has a ring gear extending portion 54a extending outward from the one end portion 31a of the motor casing 31 toward the motor casing 31 in the axial direction, and the circumference of the ring gear extending portion 54a is provided. Since the surface is the mounting surface of the first reduction ring gear support bearing B7, a sufficient bearing diameter can be secured without particularly increasing the diameter of the main body of the motor casing 31. [Second Embodiment]

Next, a second embodiment of the present invention will be described with reference to Fig. 6 . In the second embodiment, the difference from the first embodiment is that the first reduction ring gear support bearing B7 is inserted into the outer circumference of the ring gear extension portion 54a' of the first reduction ring gear 54, and The outer peripheral surface of the ring gear extending portion 54a' and the inner peripheral surface of the outer extending portion 61' become the first reduction ring gear supporting bearing between the inner circumferences of the outer extending portions 61' of the second end wall member half body He2 The mounting surface of the B7.

Since the other configuration of the power-assisted bicycle power unit U of the second embodiment is the same as that of the power unit U of the first embodiment, the components corresponding to the first embodiment are shown in FIG. The same reference symbols are left in the addition, and their re-construction description is omitted. As described above, in the second embodiment, the same operational effects as those of the first embodiment can be expected. [Third embodiment]

Next, a third embodiment of the present invention will be described with reference to Fig. 7 . In the first and second embodiments, the outer peripheral portions 61 and 61' protruding from the inner side surfaces of the end wall member He in the axial direction define an annular gap between the opposing circumferential surfaces of the inner extending portions 62 and 62'. And the ring gear extensions 54a, 54a' of the first reduction ring gear 54 protrude into the annular gap, and the circumferential surface of the ring gear extensions 54a, 54a' facing the annular gap is set as the first reduction ring The mounting surface of the bearing B7 for the gear support.

On the other hand, in the third embodiment, the inner extending portion 62" is integrally connected to the inner peripheral side of the outer extending portion 61" which is formed on the inner side surface of the end wall member He in the axial direction, thereby improving the inner side. The rigidity of the extending portion 62" (the second reduction ring gear 55) is such that the extended end of the ring gear extending portion 54a" of the first reduction ring gear 54 is closer to the extended end of the inner extending portion 62".

The other configuration of the power-assisted bicycle power unit U of the third embodiment is the same as that of the power unit U of the second embodiment. Therefore, in FIG. 7, each component is a component corresponding to the second embodiment. The same reference symbols are left in the addition, and their re-construction description is omitted. Further, in the third embodiment, the same operational effects as those of the first and second embodiments can be expected.

In the above, the first to third embodiments of the present invention have been described, but various modifications can be made without departing from the scope of the invention.

For example, in the above embodiment, the power unit U is disposed on the rear wheel, but it may be disposed on the front wheel.

Further, in the above-described embodiment, the vehicle in which the power unit U is mounted is a power-assisted bicycle. However, the power unit of the present invention is also applicable to a pedal-type electric assist tricycle or a four-wheeled vehicle. .

Further, in the above-described embodiment, the vehicle in which the power unit U is mounted is an electric assist vehicle that uses electric power and human power (foot input) for driving the wheels (that is, the electric assist bicycle and the electric assist three or four. The form of the wheeled vehicle is described, but the present invention is also applicable to an electric vehicle of a type that only electrically drives a wheel (for example, an electric two-wheeled vehicle or an electric three- or four-wheeled vehicle).

Further, although not shown in the above embodiment, in order to prevent dragging resistance of the motor M, it is also possible to arrange only the second deceleration between the hub outer casing H (end wall member He) and the second reduction ring gear 55. The one-way clutch that the ring gear 55 transmits power to the hub housing H side.

11‧‧·Wheel axle

11a‧‧‧ claw storage hole

14‧‧‧ bolt

15n‧‧‧Support nut

15r‧‧·Wheel support ring

16, 18‧‧‧ nuts

17‧‧‧Brake ring

21‧‧‧ Passive sprocket

22‧‧‧Transmission bracket

22A‧‧‧1st bracket half

22Aa‧‧‧One end of the first bracket half

22Ab‧‧‧The other end of the first bracket half

22B‧‧‧2nd bracket half

22Ba‧‧‧ bracket extension

23‧‧‧ Variable speed sun gear

23a‧‧‧ Ratchet groove

24‧‧‧ Variable speed planetary gear

25‧‧‧ Variable speed ring gear

25a, 54a, 54a', 54a" ‧‧" ring gear extension

25m, 54m‧‧‧ ring gear body

25mg‧‧‧ internal teeth meshing with variable speed planetary gears

27‧‧‧ bracket shaft

28‧‧‧Washers

29‧‧‧Knock ring

31‧‧‧Motor housing

31a‧‧‧One end of the motor casing

31b‧‧‧End wall portion of the motor casing (the other end)

32‧‧‧ Stator

33‧‧‧Rotor

34‧‧‧Motor shaft

35‧‧‧Stent members

41‧‧‧ Ratchet Claw

41a‧‧‧ claw body

41as‧‧‧ claw front part of the claw body

41b‧‧‧ base end

41bs‧‧‧ claw end of the base end

41m‧‧‧ middle part

42‧‧‧ring spring

43‧‧‧Operating roller

431‧‧‧1st roller half

431i‧‧‧ recess

432‧‧‧2nd roller half

432t‧‧‧Operation part

44‧‧‧Return spring

44a‧‧‧ movable end

44b‧‧‧fixed end

45‧‧‧ Spring bearing ring

46‧‧‧Fixed ring

51‧‧‧Deceleration sun gear

52‧‧‧Deceleration planetary gears

52a‧‧‧1st gear

52b‧‧‧2nd gear

53‧‧‧Deceleration bracket

53a‧‧‧1st bracket half

53au‧‧‧Connected wrist

53b‧‧‧2nd bracket half

54‧‧‧1st reduction ring gear

54mg‧‧‧ internal teeth meshing with the first gear

55‧‧‧2nd reduction ring gear

56‧‧‧Deceleration bracket shaft

57‧‧‧Fixed ring

61, 61', 61" ‧ ‧ outer extension (end wall extension)

62, 62', 62" ‧ ‧ inner extension (end wall extension)

63‧‧‧The inner circumference of the first end wall member half

71‧‧‧ actuation board

72‧‧‧Operation lever

B1‧‧·1st bearing for hub support (bearing for hub support)

B2‧‧·Second bearing for hub support (bearing for hub support)

B3‧‧‧Support for bearings

B4‧‧‧Resting ring gear support bearing

B5‧‧‧1st bearing for motor shaft support

B5'‧‧‧2nd bearing for motor shaft support

B6‧‧‧1st bearing for support of reduction bracket

B6'‧‧‧2nd bearing for support of reduction bracket

B7‧‧‧1st reduction gear bearing support (bearing)

C1‧‧‧1st one-way clutch

C2‧‧‧2nd one-way clutch

CU‧‧‧Operating unit

Unit housing for the CUc‧‧ operating unit

ECU‧‧‧Electronic control unit

H‧‧·wheel shell

He‧‧‧ end wall member (one end wall)

He1‧‧‧1st end wall member half

He2‧‧‧2nd end wall member half

Hm‧‧·Wheel shell body

End wall of the Hmb‧‧ hub housing body (the other end wall)

One end of the Hme‧‧ wheel housing body

M‧‧ motor

MD‧‧‧Motor drive system

OT‧‧ unidirectional transmission mechanism

R‧‧‧Deceleration Mechanism Department

S‧‧‧ Shift mechanism (switching device)

S1‧‧‧1st side wall portion (side wall portion)

S2‧‧‧2nd side wall part (side wall part)

T‧‧‧Transmission Mechanism Department

U‧‧‧Power unit for electric assisted bicycles (power unit for electric vehicles)

Fig. 1 is an overall longitudinal sectional view of a power unit for a power-assisted bicycle according to a first embodiment of the present invention. (First Embodiment) Fig. 2 is an enlarged view of a direction of view of an arrow 2 in Fig. 1 . (First Embodiment) Fig. 3 is an enlarged view of a view of an arrow 3 in Fig. 1 (a cross-sectional view taken along line 3-3 of Fig. 4). (First Embodiment) Fig. 4 is a view showing a locked state of a sun gear with respect to a hub axle. Fig. 4(A) is a cross-sectional view taken along line 4A-4A of Fig. 3, and Fig. 4(B) is a 4B- of Fig. 3. Section 4B line diagram. (First Embodiment) Fig. 5 is a view showing an unlocked state of a sun gear with respect to a hub axle, Fig. 5(A) is a corresponding view of Fig. 4(A), and Fig. 5(B) is Fig. 4(B) Corresponding map. (First embodiment) Fig. 6 is a view corresponding to Fig. 2 showing a second embodiment of the present invention. (Second embodiment) Fig. 7 is a view corresponding to Fig. 2 and Fig. 6 showing a third embodiment of the present invention. (Third embodiment)

Claims (3)

A power unit for an electric vehicle is configured such that an end wall portion and a other end wall portion of a hub casing of a wheel are rotatably supported by a hub axle, and a motor and a driving force of the motor are decelerated and transmitted to the hub casing The speed reduction mechanism portion is arranged in the axial direction and housed in the hub casing, and the motor has a bottomed cylindrical motor casing that opens at one end and faces the one end wall portion of the hub casing, and is a motor casing. The other end portion of the bottom wall is fixed to and supported by the hub axle. The power unit for an electric vehicle includes: a reduction sun gear that is rotatably driven by the motor; and a deceleration bracket that rotatably supports the first a gear and a second gear, wherein the first gear meshes with the reduction sun gear, the second gear is coaxially arranged with respect to the first gear; and the first reduction ring gear is fitted to the one end of the motor casing and Engaged in the first gear; and the second reduction ring gear is disposed on the hub casing and meshed with the second gear Between the first reduction ring gear and the hub shell, so that the plug with the first reduction ring gear is rotatably supported by the hub bearing housing. The power unit for an electric vehicle according to claim 1, wherein the side wall portions of the first and second gears are sandwiched in the axial direction of the speed reduction bracket, and are rotatably supported by the hub shaft. The power unit for an electric vehicle according to claim 1 or 2, wherein the first reduction ring gear integrally has a ring gear extension portion that is more toward the motor in the axial direction than the aforementioned one end portion of the motor casing The outer peripheral surface or the inner peripheral surface of the ring gear extending portion is extended as a mounting surface on the first reduction ring gear side of the bearing.