Drive unit for human-powered vehicles

Abstract

To provide a drive unit for a human powered vehicle which can inhibit entry of foreign objects from a gap between a housing and a rotary shaft.SOLUTION: A drive unit 1 for a human powered vehicle includes: a housing 10; a rotary shaft 20 protruding to an external space of the housing 10; a drive member 40 including at least one of an electric motor 41 and a transmission 42; a bearing 30 rotatably supporting the rotary shaft 20; and a cover member 50 which is provided at an outer periphery part around a rotation center axis C1 of the rotary shaft 20 and is disposed spaced apart from the housing 10. The cover member 50 is at least partially disposed at the external space of the housing 10 and covers a gap between an outer peripheral surface 21C around the rotation center axis C1 of the rotary shaft 20 and an inner peripheral surface 11A, on which a through hole 9 of the housing 10 is defined, when viewed from a direction in which the rotation center axis C1 extends.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to the technology of drive units for human-powered vehicles. [Background technology]

[0002] Conventionally, drive units for human-powered vehicles have been known. For example, the drive unit disclosed in Patent Document 1 includes a crankshaft and a housing that rotatably supports the crankshaft via a bearing. The crankshaft is inserted into a through hole of the housing. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-24700 A Summary of the Invention [Problem to be solved by the invention]

[0004] Because there is a gap between the through hole of the housing and the rotating shaft, foreign matter such as water, mud, and dust may get into the housing. If foreign matter gets into the housing, various problems may occur, such as an increase in the rotational resistance of the crankshaft.

[0005] An object of the present disclosure is to provide a drive unit for a human-powered vehicle that can prevent foreign matter from entering through the gap between the housing and the rotating shaft. [Means for solving the problem]

[0006] A drive unit according to a first aspect of the present disclosure is a drive unit for a human-powered vehicle, comprising: a housing forming an internal space and having a through hole connecting the internal space and an external space; a rotating shaft having a rotation central axis and a portion thereof disposed in the internal space and protruding into the external space of the housing through the through hole; a driving member disposed in the internal space and including at least one of an electric motor and a transmission; a bearing disposed in the internal space and at least one of the through holes and rotatably supporting the rotating shaft; and a cover member provided on an outer periphery around the rotation central axis of the rotating shaft and disposed at a distance from the housing, at least a portion of the cover member being disposed in the external space of the housing and covering a gap between an outer periphery surface around the rotation central axis of the rotating shaft and an inner periphery surface of the housing that defines the through hole, as viewed in a direction in which the rotation central axis extends. The cover member includes an attachment portion attached to the rotating shaft, a wall portion extending radially from the attachment portion with respect to the rotation central axis and formed in a ring shape, and a protrusion portion extending from a radial outer end portion of the wall portion toward the housing and formed in a ring shape, wherein the outer peripheral surface of the protrusion portion on the radially outer side with respect to the rotation central axis has a first tapered surface that inclines toward the rotating shaft as it approaches the housing in the extension direction of the rotation central axis, and the outer surface of the housing has a second tapered surface opposite to the first tapered surface. According to the drive unit of the first aspect, it is possible to prevent foreign matter from entering through the gap between the housing and the rotating shaft. Furthermore, according to the drive unit of the first side face, foreign matter that has entered between the housing and the cover member can be easily expelled from between the first tapered surface and the second tapered surface.

[0007] A drive unit according to a second aspect of the present invention, The outer wall of the housing has an annular groove formed therein in which the free end of the projection is disposed. According to the drive unit of the second aspect, it is possible to further prevent foreign matter from entering through the gap between the housing and the rotating shaft.

[0008] First or second aspect In a third aspect of the drive unit according to The first tapered surface is formed so as to be equidistant from the second tapered surface, or so as to increase in distance from the second tapered surface as it moves from the free end of the protrusion toward the base end of the protrusion. According to the third aspect of the drive unit, Foreign matter that has entered between the housing and the cover member can be more easily expelled from between the first tapered surface and the second tapered surface.

[0009] Any one of the first to third aspects In a fourth aspect of the drive unit according to The outer circumferential surface of the protrusion further includes a third tapered surface that is connected to the first tapered surface and inclines in the direction in which the rotation central axis extends so as to approach the rotation axis as it moves away from the housing. According to the drive unit of the fourth aspect, foreign matter that has entered between the housing and the cover member can be easily expelled from between the first tapered surface and the second tapered surface.

[0010] Any one of the first to fourth aspects In a fifth aspect of the drive unit according to The outer surface of the housing further includes a fourth tapered surface connected to the second tapered surface and inclined in the direction in which the rotation central axis extends so as to move away from the rotation axis as it moves away from the free end of the protrusion. According to the drive unit of the fifth aspect, foreign matter that has entered between the housing and the cover member can be more easily expelled from between the first tapered surface and the second tapered surface.

[0011] According to the sixth aspect of the present disclosure In the drive unit, A drive unit for a human-powered vehicle comprises: a housing that forms an internal space and has a through hole that connects the internal space with an external space; a rotating shaft that has a central rotation axis and is partially disposed in the internal space and protrudes into the external space of the housing through the through hole; a driving member that is disposed in the internal space and includes at least one of an electric motor and a transmission; bearings that are disposed in the internal space and in at least one of the through holes and rotatably support the rotating shaft; and a cover member that is provided on an outer periphery around the central rotation axis of the rotating shaft and is disposed at a distance from the housing, wherein the rotating shaft includes an output shaft that is directly or indirectly connected to a crankshaft, and the cover member is provided on the outer periphery of the output shaft, at least a portion of the cover member is disposed in the external space of the housing, and covers a gap between an outer periphery surface around the central rotation axis of the rotating shaft and an inner periphery surface of the housing that defines the through hole, when viewed in a direction in which the central rotation axis extends. According to the sixth aspect drive unit, This can prevent foreign matter from entering through the gap between the housing and the rotating shaft.

[0012] No. 1 A drive unit according to any one of the seventh to sixth aspects, The housing further includes a seal member that is disposed between the bearing and the cover member and that contacts the rotating shaft. According to the seventh aspect drive unit, This further prevents foreign matter from entering through the gap between the housing and the rotating shaft.

[0013] 7th aspect In a drive unit according to the eighth aspect of the present invention, The seal member is a single lip type seal member. According to the drive unit of the 8th aspect, An increase in rotational resistance caused by contact of the seal member with the rotating shaft can be suppressed.

[0014] Any one of the first to eighth aspects In a drive unit according to a ninth aspect of the present invention, The device further includes grease arranged to fill at least a portion of a gap formed by the cover member and the housing. According to the 9th aspect drive unit, This further prevents foreign matter from entering through the gap between the housing and the rotating shaft.

[0015] A drive unit according to a tenth aspect of the present invention, the drive unit being in accordance with any one of the first to ninth aspects, The cover member is made of a resin material. According to the drive unit of the 10th aspect, The increase in weight of the drive unit can be suppressed.

[0016] 1st to 5th 5 In a drive unit of an eleventh side according to any one of the sides, the mounting portion of the cover member has at least one convex portion protruding toward the rotating shaft, and the outer periphery of the rotating shaft has at least one concave portion with which at least a portion of the at least one convex portion engages. According to the drive unit of the eleventh aspect, the cover member can be easily attached to the rotating shaft.

[0018] No. 6 Side following 12 In the drive unit on the side, the crankshaft and the output shaft are arranged coaxially, and the output shaft is arranged radially outward of the crankshaft with respect to the central axis of rotation. No. 12 The side drive unit allows the arrangement space for the crankshaft and the output shaft to be reduced.

[0019] No. 12 Side following 13 In the side drive unit, the output shaft is spaced apart from the crankshaft, and the rotating shaft further includes a transmission shaft, which is disposed radially outside the crankshaft, and the transmission shaft is disposed between the output shaft and the crankshaft. No. 13 The drive unit on the side can prevent foreign matter from entering through the gap between the housing and the transmission shaft.

[0020] No. 13 Side following 14 The drive unit on the side further includes a detection section provided on the transmission shaft for detecting a manual driving force. No. 14 The side drive unit can detect the manual driving force using the transmission shaft. Effect of the Invention

[0021] According to the drive unit of the present disclosure, it is possible to prevent foreign matter from entering through the gap between the housing and the rotating shaft. [Brief description of the drawings]

[0022] [Figure 1] FIG. 2 is a side view showing a drive unit according to an embodiment of the present invention. [Diagram 2] Cross-sectional view taken along line D5-D5 in Figure 1. [Diagram 3] A partially enlarged view of Figure 2. [Figure 4] A partially enlarged view of Figure 3. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] The configuration of a drive unit 1 of a human-powered vehicle according to one embodiment of the present invention will be described below. Figures 1 to 3 are used to explain the configuration of the drive unit 1 according to one embodiment of the present invention.

[0024] The human-powered vehicle to which the drive unit 1 is attached is a vehicle that has at least one wheel and can be driven at least by human-powered driving force. Human-powered vehicles include various types of bicycles, such as mountain bikes, road bikes, city bikes, cargo bikes, hand bikes, and recumbents. The number of wheels that a human-powered vehicle has is not limited. Human-powered vehicles include, for example, one-wheeled vehicles and vehicles with two or more wheels. Human-powered vehicles are not limited to vehicles that can be driven only by human-powered driving force. Human-powered vehicles include E-bikes that use not only human-powered driving force but also the driving force of an electric motor for propulsion. E-bikes include electrically assisted bicycles whose propulsion is assisted by an electric motor.

[0025] The drive unit 1 includes a housing 10 that defines an internal space 8. The drive unit 1 includes a rotating shaft 20, a portion of which is disposed in the internal space 8 of the housing 10. The rotating shaft 20 includes a crankshaft 21. The crankshaft 21 has a substantially cylindrical shape. The crankshaft 21 may be formed as a solid body. The crankshaft 21 has a rotation center axis C1. The crankshaft 21 is provided rotatably about the rotation center axis C1 relative to the housing 10. In this specification, the direction in which the rotation center axis C1 of the crankshaft 21 extends is defined as a first direction X1 in Figs. 2 to 4.

[0026] The housing 10 is formed with a through hole 9 that connects the internal space 8 of the housing 10 to an external space. In this embodiment, the through hole 9 includes a first through hole 11 formed in a first side wall 10A of the housing 10 in the first direction X1, and a second through hole 12 formed in a second side wall 10B of the housing 10 in the first direction X1. The first through hole 11 is formed to extend in the first direction X1 and connect the internal space 8 of the housing 10 to an external space. The second through hole 12 is formed to extend in the first direction X1 and connect the internal space 8 of the housing 10 to an external space.

[0027] The crankshaft 21 protrudes into the external space of the housing 10 through the through hole 9. A first end 21A of the crankshaft 21 in the first direction X1 protrudes into the external space of the housing 10 through the first through hole 11. A second end 21B disposed opposite the first end 21A of the crankshaft 21 in the first direction X1 protrudes into the external space of the housing 10 through the second through hole 12.

[0028] The rotating shaft 20 further includes an output shaft 22 connected directly or indirectly to the crankshaft 21. The output shaft 22 has a substantially cylindrical shape. The output shaft 22 and the crankshaft 21 are arranged coaxially. The output shaft 22 has a rotation center axis C1 and is provided to be rotatable about the rotation center axis C1 relative to the housing 10. The output shaft 22 is provided radially outward of the crankshaft 21 with respect to the rotation center axis C1. The output shaft 22 is provided on the second end 21B side of the crankshaft 21. A portion 22A of the output shaft 22 in the first direction X1 protrudes into the external space of the housing 10 through the second through hole 12.

[0029] The crankshaft 21 and the rear wheel are connected by a drive mechanism. The rear wheel is driven by the rotation of the crankshaft 21. The drive mechanism includes a rotating member connected to the crankshaft 21. The rotating member may include a sprocket, a pulley, or a bevel gear. The crankshaft 21 and the rotating member may be connected to rotate together, or may be connected via a one-way clutch 15. The one-way clutch 15 includes, for example, a roller clutch, a sprag clutch, a pawl ratchet clutch, or a face-chate clutch. The one-way clutch 15 is configured to rotate the rotating member forward when the crankshaft 21 rotates forward, and to allow relative rotation between the crankshaft 21 and the rotating member when the crankshaft 21 rotates backward.

[0030] The one-way clutch 15 is disposed between the crankshaft 21 and the output shaft 22 in a transmission path of the manual driving force. A transmission shaft 17 configured to transmit the manual driving force from the crankshaft 21 to the one-way clutch 15 may be provided between the crankshaft 21 and the one-way clutch 15. For example, the transmission shaft 17 is formed by a hollow shaft and is disposed coaxially with the crankshaft 21. The transmission shaft 17 may be provided with a detector for detecting the manual driving force. The detector for detecting the manual driving force may be disposed on the outer periphery of the transmission shaft 17. The detector includes a strain sensor, a magnetostrictive sensor, or the like.

[0031] The drive unit 1 includes a bearing 30 disposed in at least one of the internal space 8 and the through hole 9 of the housing 10. The bearing 30 includes a first bearing 31, a second bearing 32, and a third bearing 33. The first bearing 31 is disposed in the internal space 8 of the housing 10, the first through hole 11, or both the internal space 8 and the first through hole 11 of the housing 10. The first bearing 31 rotatably supports the crankshaft 21 with respect to the housing 10. The second bearing 32 is disposed in the internal space 8 of the housing 10, the second through hole 12, or both the internal space 8 and the second through hole 12 of the housing 10. The second bearing 32 rotatably supports the output shaft 22 with respect to the housing 10. The third bearing 33 is disposed between an inner periphery of the output shaft 22 and an outer periphery of the crankshaft 21. The output shaft 22 rotatably supports the crankshaft 21 via the third bearing 33. The first bearing 31, the second bearing 32, and the third bearing 33 may each be a ball bearing, a roller bearing, or a plain bearing. In this embodiment, the first bearing 31 and the second bearing 32 are configured as radial bearings, and the third bearing 33 is configured as a needle bearing.

[0032] The drive unit 1 includes a drive member 40. The drive member 40 is disposed in the internal space 8 of the housing 10 and includes at least one of an electric motor 41 and a transmission 42. In this embodiment, the transmission 42 includes a reduction gear. The drive member 40 may include only the electric motor 41. The drive member 40 may include only the transmission 42 without including the electric motor 41. The drive member 40 may include only the transmission, for example, as described in EP 2379402. The drive member 40 may include an electric motor, a reduction gear, and a transmission, for example, as described in US 2016 / 0040763, WO 2016 / 062436, and WO 2017 / 080726. The configurations of the electric motor 41 and the transmission 42 are not particularly limited.

[0033] The electric motor 41 is configured to provide a propulsive force to the human-powered vehicle. The electric motor 41 is configured to transmit a rotational force to rear wheels of the human-powered vehicle, for example, via the output shaft 22. The electric motor 41 includes an output shaft 41A. The output shaft 41A is supported by the housing 10 via a pair of fourth bearings 34 so as to be rotatable relative to the housing 10. The fourth bearings 34 may be ball bearings, roller bearings, or plain bearings. The electric motor 41 is provided in the housing 10. The electric motor 41 is disposed in the internal space 8 of the housing 10.

[0034] A one-way clutch 16 is preferably provided in the power transmission path between the electric motor 41 and the crankshaft 21. The one-way clutch 16 is formed so as to suppress transmission of the rotational force of the crankshaft 21 to the electric motor 41 when the crankshaft 21 is rotated in the direction in which the human-powered vehicle moves forward. The one-way clutch 16 includes any one of a roller clutch, a pawl ratchet clutch, and a sprag clutch.

[0035] The transmission 42 is coupled to the output shaft 41A of the electric motor 41, and reduces the rotation speed of the electric motor 41. The rotational force of the electric motor 41 is transmitted to the transmission 42. The rotational force transmitted to the transmission 42 is transmitted to the rear wheels of the human-powered vehicle via the output shaft 22 and members of the drive mechanism. The type of the transmission 42 is not particularly limited. The transmission 42 includes at least one of, for example, a pair of gears that mesh with each other, a planetary gear mechanism, a pair of sprockets and chains, and a pair of pulleys and belts.

[0036] The drive unit 1 includes a cover member 50. The cover member 50 is configured to suppress the intrusion of foreign matter such as water, mud, and dust into at least one of the internal space 8, the first through hole 11, and the second through hole 12 of the housing 10. In this embodiment, the cover member 50 includes, for example, a first cover member 50A disposed near the first end 21A of the crankshaft 21, and a second cover member 50B disposed near the second end 21B of the crankshaft 21. In this embodiment, the dimensions of the first cover member 50A are different from the dimensions of the second cover member 50B, but the first cover member 50A and the second cover member 50B have substantially symmetrical shapes with respect to a plane perpendicular to the rotational center axis C1 of the crankshaft 21.

[0037] The drive unit 1 further includes a seal member 60 provided in the housing 10. The seal member 60 includes, for example, a first seal member 60A provided near the first end 21A of the crankshaft 21 and a second seal member 60B provided near the second end 21B of the crankshaft 21. The first seal member 60A is disposed in the internal space 8 of the housing 10, the first through hole 11, or both the internal space 8 and the first through hole 11 of the housing 10. The first seal member 60A is disposed on the radial outside of the crankshaft 21. The second seal member 60B is disposed in the internal space 8 of the housing 10, the second through hole 12, or both the internal space 8 and the second through hole 12 of the housing 10. The second seal member 60B is disposed on the radial outside of the output shaft 22.

[0038] The seal member 60 is a single-lip type seal member. The seal member 60 contacts the rotating shaft 20 between the bearing 30 and the cover member 50. For example, a part of the first seal member 60A contacts the crankshaft 21 between the first bearing 31 and the first cover member 50A. A part of the second seal member 60B contacts the output shaft 22 between the second bearing 32 and the second cover member 50B. The seal member 60 is made of a resin material. The resin material may have elasticity. The resin material includes, for example, ABS resin, synthetic rubber, etc. The seal member 60 may be made of a metal material.

[0039] The configuration of the cover member 50 of the drive unit 1 according to one embodiment of the present invention will be described. Figures 3 and 4 are used to explain the configuration of the cover member 50. The first cover member 50A and the second cover member 50B have the same shape except that the first cover member 50A is attached to the crankshaft 21 and the second cover member 50B is attached to the output shaft 22. Therefore, the first cover member 50A will be described and the second cover member 50B will be briefly described.

[0040] The cover member 50 is formed in a substantially annular shape. The cover member 50 is provided on the outer periphery of the rotation axis C1 of the rotating shaft 20. The first cover member 50A is provided on the outer periphery of the rotation axis C1 of the crankshaft 21. The second cover member 50B is provided on the outer periphery of the rotation axis C1 of the output shaft 22. The cover members 50 are arranged on the housing 10 with a gap therebetween. Preferably, the cover member 50 is made of a resin material. The cover member 50 may be made of a metal material.

[0041] At least a part of the cover member 50 is disposed in the external space of the housing 10. In this embodiment, all parts of the cover member 50 are disposed in the external space of the housing 10. The cover member 50 covers a gap between the outer peripheral surface 21C of the rotating shaft 20 around the rotation center axis C1 and the inner peripheral surface 11A of the housing 10 that defines the through hole 9, as viewed from the direction in which the rotation center axis C1 extends. The first cover member 50A covers a gap between the outer peripheral surface 21C of the rotating shaft 20 around the rotation center axis C1 and the inner peripheral surface 11A of the housing 10 that defines the first through hole 11, as viewed from the direction in which the rotation center axis C1 extends. The second cover member 50B covers a gap between the outer peripheral surface 21C of the output shaft 22 around the rotation center axis C1 and the inner peripheral surface 11A of the housing 10 that defines the second through hole 12, as viewed from the direction in which the rotation center axis C1 extends. Each inner circumferential surface 11A includes a first chamfered portion 11B and a second chamfered portion 11C at both ends in the direction in which the rotation center axis C1 extends.

[0042] The cover member 50 includes an attachment portion 51 that is attached to the rotating shaft 20. The attachment portion 51 of the first cover member 50A is attached to the crankshaft 21. The attachment portion 51 of the first cover member 50A is formed so as to follow the entire circumference of the outer circumferential surface 21C of the crankshaft 21. The attachment portion 51 of the second cover member 50B is formed so as to follow the entire circumference of the outer circumferential surface 21C of the output shaft 22. The attachment portion 51 has at least one protruding portion 51A that protrudes toward the rotating shaft 20. The outer circumferential surface 21C of the rotating shaft 20 has at least one recessed portion 21D with which at least a portion of the at least one protruding portion 51A engages. The protruding portion 51A of the attachment portion 51 of the first cover member 50A protrudes toward the crankshaft 21. The recessed portion 21D formed on the outer circumferential surface 21C of the crankshaft 21 engages with the protruding portion 51A of the first cover member. The protrusion 51A of the attachment portion 51 of the second cover member 50B protrudes toward the output shaft 22.

[0043] The recess 21D formed on the outer circumferential surface 21C of the output shaft 22 engages with the protrusion 51A of the second cover member 50B. At least one protrusion 51A may be formed in an annular shape, or may be formed in a plurality of spaces around the rotation central axis C1. At least one recess 21D has a shape complementary to at least one protrusion 51A. At least one recess 21D may be formed in an annular shape, or may be formed in a plurality of spaces around the rotation central axis C1. The cover member 50 is fixed to the outer circumferential surface 21C of the rotating shaft 20, for example, by fitting the protrusion 51A of the mounting portion 51 into the recess 21D of the rotating shaft 20. The cover member 50 may be fixed to the rotating shaft 20 by adhesion. The cover member 50 may be formed integrally with the rotating shaft 20. The cover member 50 is rotatable integrally with the rotating shaft 20 by being fixed to the rotating shaft 20.

[0044] The cover member 50 includes a wall portion 52 extending radially from the attachment portion 51 with respect to the rotation center axis C1 of the rotating shaft 20. The wall portion 52 extends radially outward from a middle portion of the attachment portion 51 in the first direction X1, for example. The wall portion 52 extends radially outward beyond an inner circumferential surface 11A that defines the through hole 9. The wall portion 52 is formed in an annular shape. The wall portion 52 is formed in an annular shape, for example, when viewed from the extension direction of the rotation center axis C1.

[0045] The cover member 50 includes a protrusion 53 extending from a radially outer end of the wall portion 52 toward the housing 10. The protrusion 53 extends, for example, from the radially outer end of the wall portion 52 toward the housing 10 in the first direction X1. The protrusion 53 is formed in an annular shape. The protrusion 53 is formed, for example, in an annular shape when viewed from the extension direction of the rotation center axis C1.

[0046] An annular groove 14 in which a free end 53C of the protrusion 53 is disposed is formed in the outer wall 13 of the housing 10. The free end 53C of the protrusion 53 is, for example, an end of the protrusion 53 on the housing 10 side in the first direction X1. The groove 14 is formed, for example, in the outer surface of the housing 10 in the first direction X1 so as to be recessed from the outer space of the housing 10 toward the inner space 8 of the housing 10. The groove 14 is formed, for example, in an annular shape centered on the rotation center axis C1 when viewed from the direction in which the rotation center axis C1 extends. The protrusion 53 is disposed at a distance from an inner wall surface 14D of the groove 14.

[0047] The outer wall portion 13 of the housing 10 includes an outer surface 13A. The outer surface 13A includes a first outer surface 13B disposed radially inward from the groove 14 with respect to the rotation central axis C1, and a second outer surface 13C disposed radially outward from the groove 14 with respect to the rotation central axis C1. The first outer surface 13B is formed to have a step with respect to the second outer surface 13C. The first outer surface 13B is formed to be recessed toward the center of the rotation shaft 20 in the first direction X1 more than the second outer surface 13C. The wall portion 52 is disposed with a gap in the first direction X1 with respect to the first outer surface 13B of the housing 10. When viewed from the direction from the radial outside toward the radial inside with respect to the rotation central axis C1, the protrusion portion 53 is formed to cover the gap between the wall portion 52 and the first outer surface 13B of the housing 10.

[0048] The wall portion 52 covers the gap S between the outer circumferential surface 21C of the rotating shaft 20 and the inner circumferential surface 11A of the through hole 9 of the housing 10, thereby preventing foreign matter such as water, mud, and dust from entering through the gap S. The projection portion 53 and the groove 14 bend the gap between the cover member 50 and the groove 14 to form a labyrinth structure, thereby further preventing the entry of foreign matter.

[0049] The outer peripheral surface of the protrusion 53 that is radially outward with respect to the rotation center axis C1 has a first tapered surface 53A. The first tapered surface 53A is inclined in the direction in which the rotation center axis C1 extends so as to approach the crankshaft 21 as it approaches the housing 10. The first tapered surface 53A is inclined radially inward, for example, as it approaches the bottom surface of the groove 14.

[0050] Of the protrusion 53, an outer peripheral surface 53E on the radially outer side with respect to the rotation central axis C1 further includes a third tapered surface 53B connected to the first tapered surface 53A. The third tapered surface 53B is formed, for example, in the first direction X1 so as to be farther away from the housing 10 than the first tapered surface 53A and adjacent to the first tapered surface 53A. The third tapered surface 53B is inclined in the extension direction of the rotation central axis C1 so as to approach the rotation shaft 20 as it moves away from the housing 10. The third tapered surface 53B is inclined, for example, so as to move toward the radially outer side of the rotation shaft 20 as it moves toward the bottom surface of the groove 14. The first tapered surface 53A and the third tapered surface 53B are formed such that a plane including an intersection line P between the first tapered surface 53A and the third tapered surface 53B is positioned closer to the center of the rotation shaft 20 than the second outer surface 13C when viewed from a direction extending perpendicular to the rotation central axis C1. By positioning the intersection line P between the first tapered surface 53A and the third tapered surface 53B of the protrusion 53 closer to the center of the rotation shaft 20 than the second outer surface 13C of the housing 10, it is possible to suppress the intrusion of foreign matter from the radial outside with respect to the rotation central axis C1 through a gap between the cover member 50 and the housing 10.

[0051] The outer surface 13A of the housing 10 has a second tapered surface 14A facing the first tapered surface 53A. The second tapered surface 14A is formed, for example, on a radially outer wall surface of the inner wall surface 14D of the groove 14 with respect to the rotation center axis C1. The second tapered surface 14A is inclined in the direction in which the rotation center axis C1 extends so as to approach the bottom surface of the groove 14 and approach the rotation shaft 20. The second tapered surface 14A is inclined, for example, in the first direction X1 so as to approach the radially inward direction of the rotation shaft 20 as it approaches the center of the rotation shaft 20.

[0052] The first tapered surface 53A is formed so as to be equidistant from the second tapered surface 14A in the direction from the free end 53C of the protrusion 53 toward the base end 53D of the protrusion 53, or so as to increase the distance from the second tapered surface 14A toward the base end 53D of the protrusion 53 from the free end 53C of the protrusion 53. In a plane including the central axis of rotation C1, the relationship between the inclination angle α of the acute angle side of the second tapered surface 14A with respect to the first direction X1 and the inclination angle β of the acute angle side of the first tapered surface 53A with respect to the first direction X1 is α≧β.

[0053] The outer surface 13A of the housing 10 further includes a fourth tapered surface 14B connected to the second tapered surface 14A. The fourth tapered surface 14B is formed, for example, on the wall surface of the inner wall surface 14D of the groove 14 that is radially outward with respect to the rotation center axis C1. The fourth tapered surface 14B is disposed, for example, in a position farther away from the center of the rotation shaft 20 than the second tapered surface 14A in the first direction X1, and is formed adjacent to the second tapered surface 14A. The fourth tapered surface 14B is inclined in the direction in which the rotation center axis C1 extends so as to move away from the rotation shaft 20 as it moves away from the free end 53C of the protrusion 53. The fourth tapered surface 14B is inclined in the direction in which the rotation center axis C1 extends so as to move away from the rotation shaft 20 as it approaches the second outer surface 13C of the housing 10. In a plane including the rotation center axis C1, the inclination angle of the acute angle side of the fourth tapered surface 14B with respect to the extension direction of the rotation center axis C1 is larger than the inclination angle α of the acute angle side of the second tapered surface 14A with respect to the extension direction of the rotation center axis C1. A third chamfered portion 14C is formed at a corner where a wall surface of the inner wall surface 14D of the groove 14 that is radially inward with respect to the rotation center axis C1 intersects with the first outer surface 13B.

[0054] The gaps between the first tapered surface 53A and the third tapered surface 53B of the protrusion 53 and the second tapered surface 14A and the fourth tapered surface 14B of the groove 14 are formed so as to widen as they approach the opening of the groove 14, making it easier to expel foreign matter that has entered the housing 10 to the outside.

[0055] The drive unit 1 further includes grease 70 arranged to fill at least a part of a gap formed by the cover member 50 and the housing 10. The grease 70 is arranged, for example, in a gap formed by the cover member 50 and the groove 14 of the housing 10 and the first outer surface 13B. The grease 70 can prevent foreign matter from entering the housing 10 through a gap between the groove 14 and the protrusion 53 of the cover member 50.

[0056] The drive unit 1 according to this embodiment includes the cover member 50, which can prevent foreign matter such as water, mud, and dust that is splashed up by the running of the human-powered vehicle from entering through the gap between the inner circumferential surfaces 11A of the through holes 11, 12 of the housing 10 and the rotating shaft 20. The drive unit 1 includes the single-lip type seal member 60 and the cover member 50, which can ensure sealing performance while preventing an increase in the rotational resistance of the rotating shaft 20.

[0057] (Modification) The explanations of the embodiments are merely examples of forms that the drive unit for a human-powered vehicle according to the present invention may take, and are not intended to limit the present invention. For example, the configuration of the drive unit 1 in each embodiment is merely an example, and the drive unit 1 may include various devices that are not shown in the embodiments, or may be configured not to include some of the various devices shown in the embodiments.

[0058] For example, in the embodiment, the cover member 50 is provided on the outer periphery of the crankshaft 21 and the output shaft 22, but it may be provided only on the outer periphery of the crankshaft 21, or only on the outer periphery of the output shaft 22. The seal member 60 is not limited to a single-lip type seal member, and may be, for example, a double-lip type seal member. The drive unit 1 does not need to include the grease 70.

[0059] The rotating shaft 20 may include only the crankshaft 21, or may include only the output shaft 22. The output shaft 22 and the crankshaft 21 may not be arranged coaxially, but may be arranged apart from each other in a direction intersecting the first direction X1.

[0060] The one-way clutch 15 may be omitted. When the one-way clutch 15 is omitted, the third bearing 33 may be omitted, and the input rotating shaft and the output shaft may be integrally formed as a one-piece member.

[0061] The shape of the cover member 50 is not limited to the shape of this embodiment, and for example, the cover member 50 does not need to include the protrusion 53. The protrusion 53 may include, for example, either the first tapered surface 53A or the third tapered surface A. The protrusion 53 may not need to include, for example, the first tapered surface 53A or the third tapered surface A.

[0062] The shape of the housing 10 is not limited to the shape of this embodiment, and for example, the housing 10 may not include the groove 14. The groove 14 may include, for example, either the second tapered surface 14A or the fourth tapered surface 14B. The groove 14 may not include, for example, the second tapered surface 14A or the fourth tapered surface 14B.

[0063] The length of the wall portion 52 of the cover member 50 in the radial direction of the rotation center axis C1 is, for example, two or more times, and preferably four or more times, the length of the gap S in the radial direction of the rotation center axis C1. In the first direction X1, the minimum distance between the wall portion 52 of the cover member 50 and the housing 10 is, for example, 0.1 mm or more and 5 mm or less. The minimum distance between the cover member 50 and the housing 10 is, for example, 0.1 mm or more and 5 mm or less. In order to suppress adhesion of dirt to the grease 70, preferably, the grease 70 is not disposed between the first tapered surface 53A and the third tapered surface 53B of the cover member 50.

[0064] The term "at least one" as used herein means "one or more" of the desired options. As an example, the term "at least one" as used herein means "only one option" or "both of two options" if the number of options is two. As another example, the term "at least one" as used herein means "only one option" or "any combination of two or more options" if the number of options is three or more. [Explanation of symbols]

[0065] 1...drive unit, 8...internal space, 9...through hole, 10...housing, 11...first through hole, 11A...inner peripheral surface, 12...second through hole, 13...outer wall portion, 13A...outer surface, 14...groove, 14A...second tapered surface, 14B...fourth tapered surface, 20...rotating shaft, 21...crankshaft, 21C...outer peripheral surface, 21D...recess, 22...output shaft, 30...bearing, 31...first bearing, 32...second bearing, 33...third bearing, 40...driving member, 41...electric motor, 42...transmission, 50...cover member, 51...mounting portion, 51A...projection portion, 52...wall portion, 53...projection portion, 53A...first tapered surface, 53B...third tapered surface, 53C...free end, 53D...base end portion, 53E...outer peripheral surface, 60...sealing member, 70...grease

Claims

1. A drive unit for a human-powered vehicle, a housing that defines an internal space and has a through hole that connects the internal space with an external space; a rotation shaft having a rotation center axis, a portion of which is disposed in the internal space and which protrudes into an external space of the housing through the through hole; a drive member disposed in the interior space and including at least one of an electric motor and a transmission; a bearing disposed in at least one of the internal space and the through hole, the bearing rotatably supporting the rotating shaft; a cover member provided on an outer periphery of the rotating shaft around the central axis of rotation and disposed on the housing at a distance, The cover member is at least a portion of the housing is disposed in an external space, and covers a gap between an outer peripheral surface of the rotation shaft about the rotation central axis and an inner peripheral surface of the housing that defines the through hole, as viewed from a direction in which the rotation central axis extends; The cover member is A mounting portion that is attached to the rotating shaft; a wall portion extending from the mounting portion in a radial direction with respect to the central axis of rotation and formed in an annular shape; a protrusion extending from the radially outer end of the wall portion toward the housing and formed in an annular shape, The protrusion has an outer peripheral surface on a radially outer side with respect to the rotation central axis, the outer peripheral surface having a first tapered surface that is inclined in a direction in which the rotation central axis extends so as to approach the rotation shaft as it approaches the housing, The outer surface of the housing has a second tapered surface opposite the first tapered surface.

2. The drive unit according to claim 1 , wherein an annular groove is formed in an outer wall of the housing, in which the free end of the protrusion is disposed.

3. 3. The drive unit of claim 1, wherein the first tapered surface is formed so as to be equidistant from the second tapered surface, or so as to increase in distance from the second tapered surface as the first tapered surface moves from the free end of the protrusion toward the base end of the protrusion.

4. A drive unit as described in any one of claims 1 to 3, wherein the outer surface of the protrusion portion further includes a third tapered surface connected to the first tapered surface and inclined in the direction in which the rotation center axis extends so as to approach the rotation axis as it moves away from the housing.

5. A drive unit as described in any one of claims 1 to 4, wherein the outer surface of the housing further includes a fourth tapered surface connected to the second tapered surface and inclined in the direction in which the rotation center axis extends so as to move away from the rotation axis as it moves away from the free end of the protrusion.

6. A drive unit for a human-powered vehicle, a housing that defines an internal space and has a through hole that connects the internal space with an external space; a rotation shaft having a rotation center axis, a portion of which is disposed in the internal space and which protrudes into an external space of the housing through the through hole; a drive member disposed in the interior space and including at least one of an electric motor and a transmission; a bearing disposed in at least one of the internal space and the through hole, the bearing rotatably supporting the rotating shaft; a cover member provided on an outer periphery of the rotating shaft around the central axis of rotation and disposed on the housing at a distance, The rotating shaft includes an output shaft directly or indirectly connected to a crankshaft, The cover member is provided on an outer periphery of the output shaft, At least a portion of the cover member is disposed in the exterior space of the housing, When viewed from the direction in which the rotation central axis extends, the gap is covered between an outer peripheral surface of the rotation shaft around the rotation central axis and an inner peripheral surface of the housing that defines the through hole. Drive unit.

7. The drive unit according to claim 1 , further comprising a seal member provided in the housing, the seal member being in contact with the rotating shaft between the bearing and the cover member.

8. 8. The drive unit according to claim 7, wherein the seal member is a single-lip type seal member.

9. The drive unit according to claim 1 , further comprising grease arranged to fill at least a portion of a gap formed by the cover member and the housing.

10. The drive unit according to claim 1 , wherein the cover member is made of a resin material.

11. The mounting portion of the cover member has at least one protrusion protruding toward the rotation shaft, The drive unit according to claim 1 , wherein the outer circumferential portion of the rotating shaft has at least one recess with which at least a portion of the at least one protrusion is engaged.

12. The crankshaft and the output shaft are arranged coaxially, The drive unit according to claim 6 , wherein the output shaft is disposed radially outward of the crankshaft with respect to the central axis of rotation.

13. The output shaft is provided at a distance from the crankshaft, The rotating shaft further includes a transmission shaft, the transmission shaft being disposed radially outward of the crankshaft, The drive unit according to claim 12, wherein the transmission shaft is provided between the output shaft and the crankshaft.

14. A drive unit as described in claim 13, further comprising a detection unit for detecting a manual driving force provided on the transmission shaft.

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