Drive unit for human-powered vehicle

Abstract

To provide a drive unit that can suppress concentration of stress.SOLUTION: A drive unit for a human-powered vehicle comprises a housing which includes two side surfaces in which through-holes are formed, a first connection part provided on either of the two side surfaces, and a second connection part provided on the other of the two side surfaces. An input rotary shaft to which man-powered driven force is inputted can be inserted through the through-holes. The first connection part has a first connection hole that is configured to penetrate in an axial direction of the input rotary shaft in an inserted state where the input rotary shaft is inserted through the through-holes, and to connect to a first fastener by which the first connection part is mounted on the man power driven vehicle. The second connection part at least partially overlaps with the first connection part when viewed from an axial direction, and has a second connection hole constituted to connect to a second fastener by which the second connection part is mounted on the man power driven vehicle. The first connection part is arranged to extend in a first direction from one side surface when viewed from the axial direction, and the second connection part is arranged to extend from the other side surface, in a second direction different from the first direction when viewed from the axial direction.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to technology for 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 housing including a rear flange portion that can be attached to a frame with bolts. A crankshaft is inserted into the housing. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-168314 Summary of the Invention [Problem to be solved by the invention]

[0004] A load acts on the housing of the drive unit. For example, a load acts on the housing when a rider presses down on a pedal connected to the crankshaft. In conventional drive units, a technology is desired that can alleviate stress concentration when a load acts on the housing.

[0005] One object of the present disclosure is to provide a drive unit that can reduce stress concentration. [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, and includes two side surfaces having a through hole formed therein, a first connecting portion provided on one of the two side surfaces, and a second connecting portion provided on the other of the two side surfaces. The drive unit has a housing in which an input rotating shaft to which human-powered driving force is input can be inserted into the through hole. When the input rotating shaft is inserted into the through hole, the first connecting portion has a first connecting hole that passes through in the axial direction of the input rotating shaft and is configured to connect to a first fastener that attaches the first connecting portion to the human-powered vehicle. The second connecting portion at least partially overlaps with the first connecting portion when viewed in the axial direction and has a second connecting hole that is configured to connect to a second fastener that attaches the second connecting portion to the human-powered vehicle. The first connecting portion is arranged to extend in a first direction from one of the side surfaces when viewed in the axial direction, and the second connecting portion is arranged to extend in a second direction different from the first direction from the other side surface when viewed in the axial direction. According to the drive unit on the first side surface, the first connecting portion and the second connecting portion can be appropriately positioned according to the direction of the load acting on the two side surfaces, thereby reducing the concentration of stress.

[0007] In the drive unit of the second side according to the first side, the first connecting portion and the second connecting portion are attached to the human-powered vehicle by the first fastener and the second fastener, and in a horizontal mounting state in which all wheels of the human-powered vehicle are in contact with the horizontal ground, the inclination of the first direction relative to the vertical direction is different from the inclination of the second direction relative to the vertical direction. The drive unit of the second aspect can reduce stress concentration.

[0008] In the drive unit of the third side according to the second side, an output rotating shaft can be placed in the through hole on the other side to transmit manual driving force and motor driving force from an electric motor placed in the internal space of the housing. According to the drive unit on the third side, it is possible to reduce the concentration of stress in the housing, on the other side of which the output rotation shaft can be disposed.

[0009] In a drive unit of a fourth side according to the third side, the input rotating shaft has a rotation center axis, the first connecting hole and the second connecting hole are arranged coaxially when viewed from the axial direction, the first direction is defined by a first straight line that is inclined with respect to a reference line passing through the center of the first connecting hole and the rotation center axis when viewed from the axial direction in the inserted state, the second direction is defined by a second straight line that is inclined with respect to the reference line when viewed from the axial direction, and the first angle defined by the first straight line and the reference line is greater than the second angle defined by the second straight line and the reference line. According to the drive unit of the fourth aspect, by making the first angle larger than the second angle, the first connecting portion and the second connecting portion can be appropriately positioned, thereby alleviating stress concentration.

[0010] In the drive unit of the fifth aspect according to the fourth aspect, the difference between the first angle and the second angle is set within a range of 35 degrees to 45 degrees. According to the drive unit of the fifth aspect, the difference between the first angle and the second angle can be appropriately set, so that the concentration of stress can be further alleviated.

[0011] In a drive unit having a sixth side according to the fourth or fifth side, the first straight line is inclined relative to the reference straight line so as to pass below the central axis of rotation when viewed from the axial direction in a horizontally mounted and inserted state. According to the drive unit of the sixth aspect, in a horizontally mounted and inserted state, the first direction can be defined by a first straight line passing below the central axis of rotation when viewed from the axial direction.

[0012] In the drive unit of the seventh side face that conforms to any one of the fourth to sixth side faces, the first straight line passes through the tip end of the first connecting portion and the first connecting hole when viewed in the axial direction. According to the drive unit of the seventh aspect, the first direction can be defined by the tip end of the first connecting portion and the first straight line passing through the first connecting hole when viewed in the axial direction.

[0013] In the drive unit of the eighth side surface according to any one of the fourth to seventh side surfaces, the first straight line is a straight line that bisects the first connecting hole when viewed in the axial direction. According to the drive unit of the eighth aspect, the first direction can be defined by the first straight line that bisects the first connecting hole.

[0014] In the drive unit of the ninth side face according to the eighth side face, the first connecting portion has a pair of first outer edge portions that are symmetrical with respect to the first straight line when viewed in the axial direction. According to the drive unit of the ninth aspect, the first connecting portion having the pair of first outer edge portions can be appropriately arranged.

[0015] In the drive unit of the tenth aspect according to the ninth aspect, a pair of first outer edge straight lines along the pair of first outer edge portions as viewed in the axial direction intersect with each other. According to the drive unit of the tenth aspect, the first connecting portion can be appropriately positioned so that the pair of first outer edge straight lines intersect with each other.

[0016] In a drive unit of an 11th side according to any one of the 4th to 10th sides, the second straight line is inclined with respect to the reference straight line so as to pass below the central axis of rotation when viewed from the axial direction in a horizontally mounted state and inserted state. According to the drive unit of the eleventh aspect, in a horizontally mounted and inserted state, the second direction can be defined by a first straight line passing below the central axis of rotation when viewed from the axial direction.

[0017] In the drive unit of a tenth side face according to any one of the fourth to eleventh side faces, the second straight line passes through the tip end of the second connecting portion and the second connecting hole when viewed in the axial direction. According to the drive unit of the twelfth side face, the second direction can be defined by the tip end of the second connecting portion and the second straight line passing through the second connecting hole when viewed in the axial direction.

[0018] In the drive unit of a thirteenth side face according to any one of the fourth to twelfth side faces, the second straight line is a straight line that bisects the second connecting hole when viewed in the axial direction. According to the drive unit of the thirteenth side face, the second direction can be defined by the second straight line that bisects the second connecting hole.

[0019] In the drive unit of the fourteenth side face according to the thirteenth side face, the second coupling portion has a pair of second outer edge portions that are symmetrical with respect to the second line when viewed in the axial direction. According to the drive unit of the fourteenth aspect, the second connecting portion having the pair of second outer edge portions can be appropriately arranged.

[0020] In the drive unit of the fifteenth side face according to any one of the first to seventh side faces, a pair of second outer edge straight lines along the pair of second outer edge portions as viewed in the axial direction intersect with each other. According to the drive unit of the fifteenth aspect, the second connecting portion where the pair of second outer edge straight lines intersect with each other can be appropriately positioned. [Effects of the Invention]

[0021] According to the drive unit of the present disclosure, stress concentration can be alleviated. [Brief explanation of the drawings]

[0022] [Figure 1] 1 is a right side view showing a human-powered vehicle equipped with a drive unit according to a first embodiment. [Figure 2] FIG. 2 is a left side view showing the drive unit and the frame according to the first embodiment. [Figure 3] 3 is a cross-sectional view taken along line D3-D3 in FIG. 2. [Figure 4] FIG. [Figure 5] FIG. [Figure 6] FIG. [Figure 7] FIG. [Figure 8] FIG. 4 is a right side view showing the first line, the second line, and the reference line. DETAILED DESCRIPTION OF THE INVENTION

[0023] (First embodiment) A human-powered vehicle 1 equipped with a drive unit 29 according to a first embodiment will be described. The human-powered vehicle 1 will be described with reference to FIG.

[0024] The human-powered vehicle 1 is a vehicle that has at least one wheel and can be propelled at least by human driving force. Human-powered vehicles 1 include various types of bicycles, such as mountain bikes, road bikes, city bikes, cargo bikes, hand bikes, and recumbents. There is no limit to the number of wheels that the human-powered vehicle 1 has. Human-powered vehicles 1 include, for example, unicycles and vehicles with two or more wheels. The human-powered vehicle 1 is not limited to vehicles that can be propelled solely by human driving force. Human-powered vehicles 1 include E-bikes that use not only human driving force but also the driving force of an electric motor M for propulsion. E-bikes include electrically assisted bicycles whose propulsion is assisted by an electric motor M. In the following embodiments, the human-powered vehicle 1 will be described as an electrically assisted bicycle.

[0025] In this specification, the following directional terms, such as "front," "rear," "forward," "backward," "left," "right," "sideways," "upward," and "downward," as well as any other similar directional terms, refer to those directions determined with reference to a rider facing the handlebars 22 at a reference position on the human-powered vehicle 1 (e.g., on the saddle or seat 21).

[0026] The human-powered vehicle 1 includes a crank 10, a frame 11, a seat 21, handlebars 22, a front fork 23, a front wheel 24, a rear wheel 25, a drive mechanism 26, a transmission 27, a battery 28, and a drive unit 29. The crank 10 shown in Fig. 1 includes a crankshaft 10a that is rotatable relative to the frame 11, and a pair of crank arms 10b provided at both axial ends of the crankshaft 10a. Pedals 10c are respectively connected to the pair of crank arms 10b.

[0027] A seat 21 is attached to the frame 11 via a seat post 21a. The frame 11 rotatably supports a handlebar 22 and a front fork 23. The handlebar 22 is configured so that it can be grasped by a rider. When the handlebar 22 rotates relative to the frame 11, the front fork 23 rotates, and the traveling direction of the human-powered vehicle 1 changes.

[0028] The front wheel 24 is rotatably attached to the front fork 23. The rear wheel 25 is rotatably attached to the frame 11. The drive mechanism 26 connects the crank 10 and the rear wheel 25. The drive mechanism 26 includes a chain ring 26a, a rear sprocket 26b, and a chain 26c.

[0029] The chainring 26a includes, for example, one chainring 26a. The chainring 26a may include multiple chainrings 26a. The chainring 26a is configured to rotate integrally with the crankshaft 10a when the crankshaft 10a rotates in a first rotational direction. When the chainring 26a rotates in conjunction with the rotation of the crankshaft 10a in the first rotational direction, the human-powered driving force is transmitted to the rear wheel 25. The human-powered vehicle 1 moves forward as the human-powered driving force is transmitted to the rear wheel 25. The chainring 26a may be connected to the crankshaft 10a via a one-way clutch that allows the crankshaft 10a and the chainring 26a to rotate integrally when the crankshaft 10a rotates in the first rotational direction, and that prohibits the crankshaft 10a and the chainring 26a from rotating integrally when the crankshaft 10a rotates in a second rotational direction opposite to the first rotational direction.

[0030] The rear sprocket 26b may include, for example, a plurality of rear sprockets 26b. The rear sprocket 26b may include a single rear sprocket 26b. The rear sprocket 26b is connected to the rear wheel 25. The chain 26c transmits the rotational force of the chain ring 26a to the rear sprocket 26b. The configuration of the drive mechanism 26 is not limited to this embodiment. The drive mechanism 26 may connect the crank 10 and the rear wheel 25 by, for example, a pulley and a belt.

[0031] The transmission 27 changes the gear ratio of the human-powered vehicle 1. The gear ratio indicates the ratio of the rotational speed of the rear wheel 25 to the rotational speed of the crankshaft 10a. The transmission 27 includes at least one of an external transmission and an internal transmission. In this embodiment, the transmission 27 includes an external transmission. When the transmission 27 includes an external transmission, the gear ratio is calculated, for example, by dividing the number of teeth of the chain ring 26a with which the chain 26c engages by the number of teeth of the rear sprocket 26b with which the chain 26c engages. The external transmission includes at least one of a front derailleur and a rear derailleur 27a. In this embodiment, the external transmission includes the rear derailleur 27a. The rear derailleur 27a is configured to switch the chain 26c between the multiple rear sprockets 26b when the rider operates a gear shifting device provided on the handlebar 22.

[0032] The battery 28 supplies power to components mounted on the human-powered vehicle 1. The components include, for example, a drive unit 29. The battery 28 includes, for example, at least one of a non-rechargeable battery and a rechargeable battery. The rechargeable battery is configured to be rechargeable with power from an external power source. The battery 28 is provided on the frame 11. In this embodiment, at least a portion of the battery 28 is disposed in the interior space of the frame 11. The drive unit 29 is configured to provide propulsive force to the human-powered vehicle 1.

[0033] The frame 11 will be described using FIGS. 2 and 3. FIG. 2 is a view of the frame 11 and the drive unit 29 as seen from the left side of the human-powered vehicle 1 in a horizontal position with all wheels of the human-powered vehicle 1 in contact with the horizontal ground. In this embodiment, the wheels include a front wheel 24 and a rear wheel 25. FIG. 2 schematically illustrates the frame 11. The frame 11 has a down tube 12, a seat tube 13, a chainstay 14, and a support portion 15. The support portion 15 is configured to support the drive unit 29. The support portion 15 is provided, for example, in a portion of the frame 11 where the down tube 12, the seat tube 13, and the chainstay 14 are connected to one another. The support portion 15 is formed to fit along a portion of the outer edge of the drive unit 29. The support portion 15 may be formed integrally with the frame 11 as a single member, or may be formed separately from the frame 11 and attached to the frame 11.

[0034] As shown in FIG. 3, the cross section of the support portion 15 is formed in an inverted U shape. The support portion 15 has an extension portion 16, a first protruding portion 17, and a second protruding portion 18. The extension portion 16 is formed to extend along part of the outer edge of the drive unit 29. The first protruding portion 17 and the second protruding portion 18 are formed to protrude from the extension portion 16. The first protruding portion 17 and the second protruding portion 18 are arranged so as to overlap part of the drive unit 29 in a side view when the human-powered vehicle 1 is in a horizontal position. The first protruding portion 17 and the second protruding portion 18 are arranged at a distance from each other in the left-right direction of the human-powered vehicle 1 when the human-powered vehicle 1 is in a horizontal position.

[0035] The first protrusion 17 is formed at the left end of the support part 15 when in a horizontal position. The first protrusion 17 has a first inner surface 17a and multiple first mounting holes 17b. When in a horizontal position, the first inner surface 17a is arranged to face the inside of the left and right sides of the human-powered vehicle 1. The multiple first mounting holes 17b are shaped so that first fasteners F1 can be attached from the outside of the first protrusion 17 on the left and right sides when in a horizontal position.

[0036] The first fastener F1 is configured to connect multiple components to one another. For example, the first fastener F1 is inserted through multiple components. In this embodiment, the first fastener F1 is inserted through a first connecting portion 42 of the drive unit 29 that can be attached to the frame 11, and a first protruding portion 17 of the frame 11. The first fastener F1 fastens the first connecting portion 42 to the first protruding portion 17, thereby connecting the first protruding portion 17 and the first connecting portion 42 to one another. The first fastener F1 includes, for example, at least one of a bolt and a rivet. The first fastener F1 is not shown in FIG. 2.

[0037] The multiple first mounting holes 17b penetrate the first protrusion 17 in the left-right direction of the human-powered vehicle 1 when it is in a horizontal position. As shown in Fig. 2, in this embodiment, the multiple first mounting holes 17b include three first mounting holes 17b. The number of first mounting holes 17b is not limited to this embodiment.

[0038] The second protrusion 18 shown in FIG. 3 is formed on the right end of the support portion 15 when the vehicle is in a horizontal position. The second protrusion 18 has a second inner surface 18a and multiple second mounting holes 18b. The second inner surface 18a is arranged to face the inside of the left and right sides of the human-powered vehicle 1 when the vehicle is in a horizontal position. The multiple second mounting holes 18b are formed in the same manner as the multiple first mounting holes 17b. The multiple first mounting holes 17b and the multiple second mounting holes 18b are arranged symmetrically when the vehicle is in a horizontal position. The second protrusion 18 is connected to a second connecting portion 52 of the drive unit 29, which can be attached to the frame 11, by a second fastener F2 configured in the same manner as the first fastener F1.

[0039] The drive unit 29 will be explained using Figures 2 to 8. Figure 4 is a view of the drive unit 29 as seen from the left side of the human-powered vehicle 1 in a horizontally mounted state. Figure 6 is a view of the drive unit 29 as seen from the right side of the human-powered vehicle 1 in a horizontally mounted state.

[0040] 4 and 6, the drive unit 29 is a drive unit 29 for a human-powered vehicle, and includes a housing 30 that includes two side surfaces 41, 51 with through holes 41a, 51a formed therein, a first connecting portion 42 provided on one of the side surfaces 41, 51, and a second connecting portion 52 provided on the other side surface 51 of the two side surfaces 41, 51, and through which an input rotation shaft AR1, to which human-powered driving force is input, can be inserted into the through holes 41a, 51a. In this specification, the state in which the first connecting portion 42 and the second connecting portion 52 are attached to the human-powered vehicle 1 by the first fastener F1 and the second fastener F2, and all of the wheels of the human-powered vehicle 1 are in contact with the horizontal ground, is referred to as the horizontal attachment state.

[0041] The two side surfaces 41, 51 form the outer surface of the housing 30. One side surface 41 of the two side surfaces 41, 51 forms the outer surface of the left side of the housing 30 in a horizontally mounted state. In this specification, the one side surface 41 may be referred to as the first side surface 41. The other side surface 51 of the two side surfaces 41, 51 forms the outer surface of the left side of the housing 30 in a horizontally mounted state. In this specification, the other side surface 51 may be referred to as the second side surface 51.

[0042] In this embodiment, the drive unit 29 includes a housing 30, a plurality of first inner members 60, a plurality of adjustment members 70, and a plurality of second inner members 80. The housing 30 is hollow. The housing 30 is made of magnesium, for example. As shown in FIGS. 3, 4, and 6, the housing 30 includes a first housing portion 40 and a second housing portion 50. The first housing portion 40 constitutes the left side of the housing 30 when the human-powered vehicle 1 is mounted horizontally. The second housing portion 50 constitutes the right side of the human-powered vehicle 1 when the human-powered vehicle 1 is mounted horizontally.

[0043] The second housing portion 50 is formed in a box shape that is open on the left side when mounted horizontally. The first housing portion 40 is formed so as to be able to close the opening of the second housing portion 50. When the first housing portion 40 closes the opening of the second housing portion 50, the first housing portion 40 and the second housing portion 50 are connected to each other.

[0044] The first housing portion 40 shown in Figures 3 and 4 includes a first side surface 41 and a first connecting portion 42. The first side surface 41 is the outer surface of the first housing portion 40. As shown in Figure 4, the first side surface 41 includes a first through hole 41a. The first through hole 41a is formed so that the input rotation shaft AR1 can be inserted therethrough.

[0045] The input rotation shaft AR1 is a shaft that rotates when a human-powered driving force is input. The input rotation shaft AR1 has a rotation center axis RCA1. The input rotation shaft AR1 includes, for example, a crankshaft 10a. In the axial direction AD relative to the rotation center axis RCA1, crank arms 10b are provided at both ends of the input rotation shaft AR1. The axial direction AD is parallel to the left-right direction of the human-powered vehicle 1 when the input rotation shaft AR1 is inserted through the first through-hole 41a and the second through-hole 51a and when the vehicle is mounted horizontally. The first through-hole 41a is circular when viewed from the left-right direction of the human-powered vehicle 1 when the vehicle is mounted horizontally.

[0046] The first connecting portion 42 is a portion of the housing 30 that can be attached to the first protrusion 17 of the frame 11. When viewed in the axial direction AD in the inserted state, the first connecting portion 42 extends away from the outer edge of the first side surface 41. As shown in FIGS. 2 and 3 , the first connecting portion 42 is disposed in the internal space of the support portion 15 in the horizontally mounted state. At least one first connecting portion 42 is provided on the first side surface 41. As shown in FIG. 4 , in this embodiment, a plurality of first connecting portions 42 are provided on the first side surface 41. The number of first connecting portions 42 is equal to the number of first mounting holes 17b of the first protrusion 17. The plurality of first connecting portions 42 include two first connecting portions 42A, 42B that are disposed above and in front of the rotation central axis RCA1 of the input rotation shaft AR1 in the horizontally mounted state, and one first connecting portion 42C that is disposed below and in rear of the rotation central axis RCA1 in the horizontally mounted state.

[0047] FIG. 5 illustrates one of the multiple first coupling portions 42, first coupling portion 42A, which is disposed forward and above the rotation center axis RCA1 of the input rotation shaft AR1 in the horizontally mounted state. In the horizontally mounted state, first coupling portion 42A is disposed forward of first coupling portion 42B. In this embodiment, a relatively large stress is likely to act on a portion of first coupling portion 42A, which is disposed farthest from the rotation center axis RCA1 among the multiple coupling portions 42. Therefore, drive unit 29 is configured to alleviate stress concentration in first coupling portion 42A. Because drive unit 29 is configured to alleviate stress concentration in first coupling portion 42A, this specification will describe only first coupling portion 42A shown in FIG. 5, and will omit description of the remaining first coupling portions 42B and 42C not shown in FIG. 5.

[0048] The first connecting portion 42A is disposed to extend in a first direction D1 from one side surface 41 as viewed in the axial direction AD. The first direction D1 is the direction in which the first connecting portion 42A extends toward a portion of the first housing portion 40 that is different from the first connecting portion 42A. The first direction D1 will be described later.

[0049] The first connecting portion 42A has a first connecting hole 44 that penetrates in the axial direction AD of the input rotation shaft AR1 when the input rotation shaft AR1 is inserted through the through holes 41a, 51a and is configured to connect to a first fastener F1 that attaches the first connecting portion 42A to the human-powered vehicle 1. In this embodiment, the first connecting portion 42A further has a first opposing surface 43, a base portion 45, and a tip portion 46. The first opposing surface 43 and the first connecting hole 44 of the first connecting portion 42A are configured similarly to the first opposing surface 43 and the first connecting hole 44 of the first connecting portion 42B shown in FIG. 3, and therefore the first opposing surface 43 and the first connecting hole 44 will be described using FIGS. 3 and 5.

[0050] The first opposing surface 43 is a surface that faces the first inner surface 17a of the first protruding portion 17 in the horizontally mounted state. In this embodiment, the first opposing surface 43 is a surface that faces toward the left of the human-powered vehicle 1 in the horizontally mounted state. The first connecting hole 44 is a hole for disposing the first inner member 60 in the internal space of the first connecting portion 42A. The first connecting hole 44 is formed in a cylindrical shape when viewed from the axial direction AD in the inserted state. The first connecting hole 44 is disposed coaxially with the first mounting hole 17b of the first protruding portion 17 when viewed from the axial direction AD in the inserted state.

[0051] 5 is a portion of the first connecting portion 42A that is closer to the first side surface 41 than the first connecting hole 44 when viewed from the axial direction AD in the inserted state. The tip portion 46 is a portion of the first connecting portion 42A that is farther from the first side surface 41 than the first connecting hole 44 when viewed from the axial direction AD in the inserted state. The tip portion 46 is formed in an arc shape when viewed from the axial direction AD.

[0052] The tip portion 46 does not have to be defined with reference to the first connecting hole 44. The tip portion 46 may, for example, include all of the portion of the first connecting portion 42A that is not adjacent to the first side surface 41 when viewed from the axial direction AD. The tip portion 46 may be the apex of a portion of the first connecting portion 42A that is formed in an arc shape when viewed from the axial direction AD. The base portion 45 does not have to be defined with reference to the first connecting hole 44. For example, the portion of the first connecting portion 42A other than the tip portion 46 may be the base portion 45.

[0053] The second housing portion 50 shown in FIGS. 3 and 6 includes a second side surface 51 and a second connecting portion 52. The second side surface 51 is the outer surface of the second housing portion 50. The second side surface 51 includes a second through hole 51a. The second through hole 51a is formed in a circular shape when viewed from the left and right direction of the human-powered vehicle 1 in a horizontally mounted state. The second through hole 51a is arranged coaxially with the first through hole 41a. The inner diameter of the second through hole 51a is larger than the inner diameter of the first through hole 41a. The second through hole 51a is formed so that the input rotation shaft AR1 can be inserted therethrough.

[0054] In this embodiment, an output rotation shaft AR2, to which manual driving force and motor driving force from an electric motor M disposed in the internal space of the housing 30 are transmitted, can be disposed in the through-hole in the other side surface 51. In this embodiment, the through-hole in the other side surface 51 includes a second through-hole 51a. The output rotation shaft AR2 is disposed coaxially with the input rotation shaft AR1. The output rotation shaft AR2 is inserted through the second through-hole 51a. A chain ring 26a that meshes with a chain 26c of the human-powered vehicle 1 is fixed to the output rotation shaft AR2.

[0055] The second connecting portion 52 is a portion of the housing 30 that can be attached to the second protrusion 18 of the frame 11. The second connecting portion 52 extends away from the outer edge of the second side surface 51 when viewed in the axial direction AD in the inserted state. The second connecting portion 52 is disposed in the internal space of the support portion 15 in the horizontally attached state. The second connecting portion 52 is disposed at a distance from the first connecting portion 42 in the axial direction AD in the inserted state. At least one second connecting portion 52 is provided on the second side surface 51. As shown in FIG. 6 , in this embodiment, a plurality of second connecting portions 52 are provided on the second side surface 51. The number of second connecting portions 52 is equal to the number of second mounting holes 18b of the second protrusion 18. The multiple second connecting portions 52 include, in a horizontally mounted state, two second connecting portions 52A, 52B arranged in front and above the rotation center axis RCA1 of the input rotation shaft AR1, and one second connecting portion 52C arranged in rear and below the rotation center axis RCA1.

[0056] FIG. 7 illustrates second coupling portion 52A, which, in the inserted state, is located on one side of first coupling portion 42 in the axial direction AD shown in FIG. 5 among the multiple second coupling portions 52. In the horizontally mounted state, second coupling portion 52A is located forward of second coupling portion 52B. In this embodiment, relatively large stress is likely to act on a portion of second coupling portion 52A, which is located farthest from rotation center axis RCA1 among the multiple coupling portions 52. Therefore, drive unit 29 is configured to alleviate stress concentration in second coupling portion 52A. Because drive unit 29 is configured to alleviate stress concentration in second coupling portion 52A, this specification will describe second coupling portion 52A shown in FIG. 7, and will omit description of the remaining second coupling portions 52B and 52C not shown in FIG. 7.

[0057] The second connecting portion 52A is disposed to extend from the other side surface 51 in a second direction D2 different from the first direction D1 when viewed from the axial direction AD. The second direction D2 is a direction in which the second connecting portion 52A extends toward a portion of the second housing portion 50 different from the second connecting portion 52A. The second direction D2 will be described later.

[0058] Because second connecting portion 52A is disposed to extend in second direction D2 different from first direction D1, first connecting portion 42A and second connecting portion 52A are disposed asymmetrically in the horizontal installation state. In this embodiment, first connecting portion 42A and first mounting hole 17b and second mounting hole 18b corresponding to second connecting portion 52A, which are disposed asymmetrically, are disposed symmetrically, which improves ease of manufacturing frame 11.

[0059] The second connecting portion 52A at least partially overlaps the first connecting portion 42A when viewed in the axial direction AD, and has a second connecting hole 54 configured to connect to a second fastener F2 that attaches the second connecting portion 52A to the human-powered vehicle 1. In this embodiment, the second connecting portion 52A further has a second opposing surface 53, a base portion 55, and a tip portion 56. The second opposing surface 53 and the second connecting hole 54 of the second connecting portion 52A are configured similarly to the second opposing surface 53 and the second connecting hole 54 of the second connecting portion 52B shown in FIG. 3, and therefore the second opposing surface 53 and the second connecting hole 54 will be described using FIGS. 3 and 7.

[0060] The second opposing surface 53 is a surface that faces the second inner surface 18a of the second protrusion 18 in the horizontal installation state. In this embodiment, the second opposing surface 53 is a surface that faces to the right of the human-powered vehicle 1 in the horizontal installation state. The second opposing surface 53 comes into contact with the second inner surface 18a of the second protrusion 18 in the horizontal installation state. The second connecting hole 54 is a hole for disposing the second inner member 80 in the internal space of the second connecting portion 52A. The second connecting hole 54 passes through the second connecting portion 52A in the axial direction AD in the inserted state. The second connecting hole 54 is formed in a cylindrical shape when viewed from the axial direction AD in the inserted state. In this embodiment, the first connecting hole 44 and the second connecting hole 54 are arranged coaxially when viewed from the axial direction AD.

[0061] 7 is a portion of the second connecting portion 52A that is closer to the second side surface 51 than the second connecting hole 54 when viewed from the axial direction AD in the inserted state. The tip portion 56 is a portion of the second connecting portion 52A that is farther from the second side surface 51 than the second connecting hole 54 when viewed from the axial direction AD in the inserted state. The tip portion 56 is formed in an arc shape when viewed from the axial direction AD.

[0062] The tip portion 56 does not have to be defined with reference to the second connecting hole 54. The tip portion 56 may, for example, include the entire portion of the second connecting portion 52A that is not adjacent to the second side surface 51 when viewed from the axial direction AD. The tip portion 56 may be the apex of a portion of the second connecting portion 52A that is formed in an arc shape when viewed from the axial direction AD. The base portion 55 does not have to be defined with reference to the second connecting hole 54. For example, the portion of the second connecting portion 52A other than the tip portion 56 may be the base portion 55.

[0063] 3, in the inserted state, an end face width W1 along the axial direction AD from the first opposing surface 43 to the second opposing surface 53 is smaller than an inner face width W2 along the axial direction AD from the first inner face 17a of the first protruding portion 17 to the second inner face 18a of the second protruding portion 18. In the present embodiment, the end face width W1 is smaller than the inner face width W2, and the second opposing surface 53 contacts the second inner face 18a of the second protruding portion 18, so that the first opposing surface 43 is disposed at a distance from the first inner face 17a of the first protruding portion 17 in the axial direction AD in the inserted state.

[0064] The plurality of first inner members 60 are configured to be connected to the first fasteners F1. The plurality of first inner members 60 are disposed in the internal spaces of the plurality of first connecting portions 42. FIG. 3 illustrates one of the plurality of first inner members 60. Because the plurality of first inner members 60 are configured similarly to one another, in this specification, only the first inner member 60 shown in FIG. 3 will be described, and a description of the remaining first inner members 60 not shown in FIG. 3 will be omitted.

[0065] The first inner member 60 is formed in a cylindrical shape when viewed in the axial direction AD in the inserted state. The first inner member 60 is made of aluminum, for example. The first inner member 60 may be formed integrally with the first connecting portion 42 as a single member by insert molding.

[0066] The multiple adjustment members 70 are configured to fill gaps between the multiple first connecting portions 42 and the second protruding portions 18. The multiple adjustment members 70 are provided on the multiple first inner members 60. FIG. 3 shows one of the multiple adjustment members 70. Because the multiple adjustment members 70 are configured similarly to one another, this specification will describe the adjustment member 70 shown in FIG. 3, and descriptions of the remaining adjustment members 70 not shown in FIG. 3 will be omitted. The adjustment member 70 is formed in a cylindrical shape when viewed from the axial direction AD in the inserted state. An internal thread portion is formed on the inner circumferential surface of the adjustment member 70 to threadably engage with the external thread portion of the first fastener F1. In the drawings, the external thread portion of the first fastener F1 and the internal thread portion of the adjustment member 70 are omitted.

[0067] The adjustment member 70 is fixed to the inner circumferential surface of the first inner member 60. The adjustment member 70 is fixed to the inner circumferential surface of the first inner member 60 by, for example, press-fitting. The adjustment member 70 may be fixed to the inner circumferential surface of the first inner member 60 by a method other than press-fitting. In the inserted state, the adjustment member 70 protrudes from the first inner member 60 toward the first protruding portion 17 in the axial direction AD, and comes into contact with the first inner surface 17a of the first protruding portion 17. The adjustment member 70 comes into contact with the first inner surface 17a of the first protruding portion 17, thereby filling the gap between the first opposing surface 43 and the first inner surface 17a of the first protruding portion 17.

[0068] The material of the adjustment member 70 is not particularly limited. The adjustment member 70 may be made of aluminum, for example. By providing the female thread portion of the adjustment member 70 made of aluminum in the first connecting portion 42 included in the housing 30 made of magnesium, the strength and corrosion resistance of the portion connected to the first fastener F1 can be improved.

[0069] The plurality of second inner members 80 are configured to be connected to the second fasteners F2. The plurality of second inner members 80 are disposed in the internal spaces of the plurality of second connecting portions 52. FIG. 3 illustrates one of the plurality of second inner members 80. Because the plurality of second inner members 80 are configured similarly to one another, in this specification, only the second inner member 80 shown in FIG. 3 will be described, and a description of the remaining second inner members 80 not shown in FIG. 3 will be omitted.

[0070] The second inner member 80 is formed in a cylindrical shape when viewed in the axial direction AD in the inserted state. The second inner member 80 is made of aluminum, for example. The second inner member 80 may be formed integrally with the second connecting portion 52 as a single member by insert molding. An internal thread portion is formed on the inner peripheral surface of the second inner member 80 to threadably mate with an external thread portion formed on the outer peripheral surface of the second fastener F2. In the drawings, the external thread portion of the second fastener F2 and the internal thread portion of the second inner member 80 are omitted. By providing the internal thread portion of the second inner member 80 made of aluminum on the second connecting portion 52 included in the housing 30 made of magnesium, the strength and corrosion resistance of the portion connected to the second fastener F2 can be improved.

[0071] When the first connecting portion 42 of the drive unit 29 is disposed in the internal space of the support portion 15, the first fastener F1 is threadedly engaged with the adjustment member 70, thereby attaching the first connecting portion 42 to the first protruding portion 17 of the frame 11. When the second connecting portion 52 is disposed in the internal space of the support portion 15, the second fastener F2 is threadedly engaged with the second inner member 80, thereby attaching the second connecting portion 52 to the second protruding portion 18 of the frame 11. In this embodiment, the gap between the first opposing surface 43 and the second inner surface 18a of the second protruding portion 18 is filled with the adjustment member 70, thereby increasing the tightening force of the first fastener F1 in the attached state.

[0072] In the horizontal mounting state, loads L1 and L2 are likely to act on the left and right sides of the housing 30 in different directions. For example, when a rider applies a pedaling force to the input rotation shaft AR1 by stepping on the pedal 10c connected to the crank arm 10b, a downward load L1 acts on the left side of the housing 30 shown in FIG. 4. The pedaling force is an example of a manual driving force. In the horizontal mounting state, the first connecting portion 42A located on the left side of the housing 30 receives the downward load L1.

[0073] 6, a chain 26c is connected to the right side of the housing 30 via the output rotation shaft AR2, and therefore, when a pedaling force is applied to the input rotation shaft AR1, chain tension acts in addition to a downward load L1. In the horizontally mounted state, the chain tension acts in addition to the load L1, and as a result, a rearward and downward load L2 acts on the right side of the housing 30. In the horizontally mounted state, the second connecting portion 52A, which is located on the right side of the housing 30, receives the rearward and downward load L2.

[0074] In this embodiment, the first direction D1 of the first connecting portion 42A and the second direction D2 of the second connecting portion 52A are different from each other, so that the first connecting portion 42A and the second connecting portion 52A can be positioned so that they face in an appropriate direction depending on the direction of the loads L1 and L2.

[0075] In the horizontal installation state, a downward load L1 acts on the left side of the housing 30. Therefore, for example, the first direction D1 and the second direction D2 may be set based on the vertical direction VD, which is related to the direction of the load L1. As shown in Fig. 8, for example, in the horizontal installation state in which the first connecting portion 42 and the second connecting portion 52 are attached to the human-powered vehicle 1 by the first fastener F1 and the second fastener F2, and all of the wheels of the human-powered vehicle 1 are in contact with the level ground, the inclination of the first direction D1 with respect to the vertical direction VD may be different from the inclination of the second direction D2 with respect to the vertical direction VD. In Fig. 8, the inclination of the first direction D1 with respect to the vertical direction VD is smaller than the inclination of the second direction D2 with respect to the vertical direction VD.

[0076] Because the inclination of the first direction D1 with respect to the vertical direction VD is smaller than the inclination of the second direction D2 with respect to the vertical direction VD, the first connecting part 42A can be arranged so as to face in a direction closer to the direction of the downward load L1 than the second connecting part 52A in the horizontally mounted state. The direction closer to the direction of the downward load L1 is a direction that, when viewed from the axial direction AD in the horizontally mounted state, forms an angle with the direction of the downward load L1 smaller than that of the second direction D2.

[0077] In the horizontally mounted state, when viewed from the axial direction AD, the angle formed between the direction of the downward load L1 and the first direction D1 is desirably an angle that can alleviate, to some extent, the concentration of stress in the first connecting portion 42A when the load L1 acts on the housing 30. The angle formed between the direction of the downward load L1 and the first direction D1 is desirably equal to or less than a predetermined threshold value, for example. The predetermined threshold value may be set appropriately depending on the magnitude of the downward load L1 expected in advance, the strength of the housing 30, and the like. By being able to arrange the first connecting portion 42A so that it faces a direction close to the direction of the downward load L1 in the horizontally mounted state, when the downward load L1 acts on the first connecting portion 42A, stress is less likely to concentrate on a part of the first connecting portion 42A, thereby alleviating the stress concentration.

[0078] 8, when viewed from the right side of the human-powered vehicle 1 in the horizontal mounting state, the second direction D2 extends upward and forward from the center C1 of the first connecting hole 44, and when viewed horizontally, is tilted more with respect to the vertical direction VD than the first direction D1. Therefore, the second connecting part 52A can be positioned so that it faces in a direction closer to the direction of the rear-downward load L2 than the first connecting part 42A. A direction closer to the direction of the rear-downward load L2 is a direction that, when viewed from the axial direction AD in the horizontal mounting state, forms an angle with the direction of the rear-downward load L2 that is smaller than the first direction D1.

[0079] In the horizontally mounted state, when viewed from the axial direction AD, the angle formed by the direction of the rearward-downward load L2 and the second direction D2 is desirably an angle that can alleviate, to a certain extent, the concentration of stress on the second connecting portion 52A when the load L2 acts on the housing 30. The angle formed by the direction of the rearward-downward load L2 and the second direction D2 is desirably within a predetermined range, for example. The predetermined range may be set appropriately depending on the magnitude of the rearward-downward load L2 that is expected in advance, the strength of the housing 30, and the like. By being able to position the second connecting portion 52A so that it faces a direction close to the direction of the rearward-downward load L2 in the horizontally mounted state, when the rearward-downward load L2 acts on the second connecting portion 52A, stress is less likely to concentrate on a part of the second connecting portion 52A, and the stress concentration can be alleviated.

[0080] For example, the first direction D1 may be defined by a first straight line LN1 that is inclined with respect to a reference line RLN that passes through the center C1 of the first connecting hole 44 and the rotation central axis RCA1 when viewed from the axial direction AD in the inserted state. The first straight line LN1 is a line for defining the first angle A1. The second direction D2 may be defined by a second straight line LN2 that is inclined with respect to the reference line RLN when viewed from the axial direction AD. The second straight line LN2 is a line for defining the second angle A2. The first straight line LN1 and the second straight line LN2 will be described later.

[0081] When the first direction D1 is defined by a first straight line LN1 and the second direction D2 is defined by a second straight line LN2, it is desirable that the first angle A1 defined by the first straight line LN1 and the reference straight line RLN is greater than the second angle A2 defined by the second straight line LN2 and the reference straight line RLN.

[0082] The reference line RLN is a line for defining both the first angle A1 and the second angle A2. The reference line RLN changes depending on the positional relationship between the rotational axis RCA1 and the center C1 of the first connecting hole 44. For example, the reference line RLN shown in FIG. 8 is a line extending rearward and downward from the center C1 of the first connecting hole 44 because the rotational axis RCA1 is located rearward and downward from the center C1 of the first connecting hole 44 in the horizontal mounting state.

[0083] The first angle A1 is the angle between the reference line RLN and the first line LN1 when viewed from the axial direction AD. The first angle A1 is defined by the acute angle formed by the reference line RLN and the first line LN1 when the housing 30 is viewed from the right side of the human-powered vehicle 1 in a horizontally mounted state, for example. The first angle A1 is measured as a positive value when the first angle A1 is formed counterclockwise from the reference line RLN when the housing 30 is viewed from the right side of the human-powered vehicle 1 in a horizontally mounted state. The first angle A1 is measured as a negative value when the first angle A1 is formed clockwise from the reference line RLN when the housing 30 is viewed from the right side of the human-powered vehicle 1 in a horizontally mounted state, for example.

[0084] The second angle A2 is the angle between the reference line RLN and the second line LN2 when viewed from the axial direction AD. The second angle A2 is measured in the same manner as the first angle A1. For example, the second angle A2 is defined as the acute angle formed by the reference line RLN and the second line LN2 when the housing 30 is viewed from the right side of the human-powered vehicle 1 in a horizontally mounted state. The second angle A2 is measured as a positive value if the second angle A2 is formed counterclockwise from the reference line RLN when the housing 30 is viewed from the right side of the human-powered vehicle 1 in a horizontally mounted state. In this embodiment, the difference between the first angle A1 and the second angle A2 is set within a range of 35 degrees to 45 degrees. The difference between the first angle A1 and the second angle A2 is preferably 41 degrees.

[0085] By setting the difference between the first angle A1 and the second angle A2 within a range of 35 degrees or more and 45 degrees or less, the first connecting portion 42A and the second connecting portion 52A can be appropriately positioned. For example, in the horizontal mounting state, the second connecting portion 52 can be positioned so that the second direction D2 is less inclined than the first direction D1 with respect to a reference line RLN that extends rearward and downward from the center C1 of the first connecting hole 44 toward the rotation central axis RCA1, and so that the second connecting portion 52 faces in a direction close to the direction of the load L2.

[0086] The first direction D1 is inclined within a range of 35 degrees or more and 45 degrees or less with respect to the second direction D2 of the second connecting part 52, which is closer to the direction of the load L2. By having the first direction D1 inclined within a range of 35 degrees or more and 45 degrees or less with respect to the second direction D2, the first connecting part 42 can be arranged so that it faces in a direction close to the direction of the load L1. By being able to arrange the second connecting part 52 so that it faces in a direction close to the direction of the load L2 and to arrange the first connecting part 42 so that it faces in a direction close to the direction of the load L1, it is possible to alleviate stress concentration in the first connecting part 42 and the second connecting part 52.

[0087] The first straight line LN1 will be described with reference to FIGS. 5 and 8. The first straight line LN1 is a line passing through the first connecting portion 42A when viewed from the axial direction AD in the inserted state. The first straight line LN1 is defined according to the shape of the first connecting portion 42A. In the present embodiment, the first straight line LN1 is set according to the pair of first outer edge portions 47 of the first connecting portion 42A shown in FIG. 5. The pair of first outer edge portions 47 are formed to be a pair with the first connecting hole 44 in between when viewed from the axial direction AD. The pair of first outer edge portions 47 are formed to be continuous with the tip portion 46. The pair of first outer edge portions 47 are formed linearly when viewed from the axial direction AD. The lengths of the pair of first outer edge portions 47 are different from each other. The pair of first outer edge portions 47 are formed to be close to each other on the tip portion 46 side.

[0088] When the pair of first outer edge portions 47 are formed close to each other on the tip end portion 46 side, a pair of first outer edge straight lines LN47 along the pair of first outer edge portions 47 intersect with each other when viewed from the axial direction AD. When the pair of first outer edge straight lines LN47 intersect with each other, a first outer edge angle A47 is defined by the pair of first outer edge straight lines LN47. The first outer edge angle A47 is the angle formed by one of the pair of first outer edge straight lines LN47 and the other of the pair of first outer edge straight lines LN47. In this embodiment, the first straight line LN1 is set as a straight line that bisects the first outer edge angle A47.

[0089] The first straight line LN1 may be set by a method different from that of the present embodiment. For example, when the pair of first outer edge portions 47 are formed parallel to each other as viewed in the axial direction AD, the first straight line LN1 may be set as a straight line that passes between the pair of first outer edge portions 47 and is parallel to the pair of first outer edge portion straight lines LN47 as viewed in the axial direction AD. For example, the first straight line LN1 may be set according to a portion of the first connecting portion 42 that is different from the pair of first outer edge portions 47. For example, because the first connecting hole 44 is formed in the first connecting portion 42, the first straight line LN1 may be set as a straight line that passes through the first connecting hole 44.

[0090] In this embodiment, the first straight line LN1 passes through the tip end 46 of the first connecting portion 42A and the first connecting hole 44 as viewed in the axial direction AD. The first straight line LN1 passes through the center C1 of the first connecting hole 44 and the base 45 as viewed in the axial direction AD. Because the first connecting hole 44 is cylindrical as viewed in the axial direction AD, the first straight line LN1 passing through the center C1 of the first connecting hole 44 bisects the first connecting hole 44 as viewed in the axial direction AD. Bisecting the first connecting hole 44 means that when the first connecting portion 42A is projected from the axial direction AD, the projected area of ​​the first connecting hole 44 is bisected. For example, if the shape of the first connecting hole 44 is asymmetric with respect to the first straight line LN1, the first straight line LN1 may bisect the projected area of ​​the first connecting hole 44 by passing through a portion of the first connecting hole 44 other than the center C1.

[0091] As shown in Fig. 8, in the horizontal installation state and in the inserted state, the first line LN1 is inclined with respect to the reference line RLN so as to pass below the rotation center axis RCA1 when viewed from the axial direction AD. In the horizontal installation state, the rotation center axis RCA1 shown in Fig. 8 is disposed rearward and below the center C1 of the first connecting hole 44. Therefore, the first line LN1 is inclined with respect to the reference line RLN so as to pass below the rotation center axis RCA1, and the first angle A1 is greater than the second angle A2. Therefore, in the horizontal installation state, the first line LN1 can be oriented closer to the vertical direction VD than the second line LN2.

[0092] The first direction D1 is set appropriately in accordance with the first straight line LN1. For example, in FIG. 8, the first direction D1 is defined as a direction parallel to the first straight line LN1. The first direction D1 is defined, for example, as a direction along the first straight line LN1 that moves away from the base 45 toward the first side surface 41 shown in FIG. 5. The first direction D1 does not have to be parallel to the first straight line LN1. For example, the first direction D1 may be a straight line such that, when viewed from the axial direction AD, the angle formed between the first direction D1 and the first straight line LN1 is equal to or smaller than a predetermined threshold.

[0093] In the horizontal installation state, the first straight line LN1 is closer to the vertical direction VD than the second straight line LN2, and therefore the first direction D1 is defined by the first straight line LN1, so the first connecting part 42 can be arranged so that it faces in a direction close to the direction of the load L1. By being able to arrange the first connecting part 42 so that it faces in a direction close to the direction of the load L1, stress concentration in the first connecting part 42 can be alleviated.

[0094] The second straight line LN2 will be described with reference to Figures 7 and 8. The second straight line LN2 is a straight line that passes through the second connecting portion 52A when viewed from the axial direction AD in the inserted state. Like the first straight line LN1, the second straight line LN2 is defined according to the shape of the second connecting portion 52A. In this embodiment, the second straight line LN2 is set according to the pair of second outer edge portions 57. The pair of second outer edge portions 57 are configured similarly to the pair of first outer edge portions 47, except that they have the same length.

[0095] When the pair of second outer edge portions 57 are configured similarly to the pair of first outer edge portions 47 except for the fact that they have the same length, a pair of second outer edge straight lines LN57 along the pair of second outer edge portions 57 intersect with each other when viewed from the axial direction AD. When the pair of second outer edge straight lines LN57 intersect with each other, a second outer edge angle A57 is defined by the pair of second outer edge straight lines LN57. The second outer edge angle A57 is defined as the angle between the pair of second outer edge straight lines LN57, similar to the first outer edge angle A47. The second straight line LN2 is set as a line that bisects the second outer edge angle A57. Because the pair of second outer edge portions 57 have the same length, the pair of second outer edge portions 57 of this embodiment are axisymmetric with respect to the second straight line LN2 when viewed from the axial direction AD.

[0096] The second straight line LN2 may be set by a method different from that of the present embodiment. For example, when the pair of second outer edge portions 57 are formed parallel to each other as viewed in the axial direction AD, the second straight line LN2 may be set as a single straight line that passes between the pair of second outer edge portions 57 and is parallel to the pair of second outer edge portions 57 as viewed in the axial direction AD. For example, the second straight line LN2 may be set according to a portion of the second connecting portion 52 that is different from the pair of second outer edge portions 57. For example, because the second connecting hole 54 is formed in the second connecting portion 52, the second straight line LN2 may be set as a straight line that passes through the second connecting hole 54.

[0097] In this embodiment, the second straight line LN2 passes through the tip end 56 of the second connecting portion 52A and the second connecting hole 54 as viewed in the axial direction AD. The second straight line LN2 passes through the center of the second connecting hole 54 and the base 55 as viewed in the axial direction AD. The second connecting hole 54 is cylindrical as viewed in the axial direction AD and is coaxial with the first connecting hole 44. Therefore, the second straight line LN2 passing through the center of the second connecting hole 54 bisects the second connecting hole 54 as viewed in the axial direction AD. Bisecting the second connecting hole 54 means that when the second connecting portion 52A is projected from the axial direction AD, the projected area of ​​the second connecting hole 54 is bisected. For example, if the second connecting hole 54 is asymmetric with respect to the second straight line LN2, the second straight line LN2 may pass through a portion of the second connecting hole 54 other than the center and bisect the projected area of ​​the second connecting hole 54.

[0098] 8, in the horizontally mounted state and in the inserted state, the second straight line LN2 is inclined with respect to the reference line RLN so as to pass below the rotation center axis RCA1 when viewed from the axial direction AD. In this embodiment, because the first angle A1 is greater than the second angle A2, the second straight line LN2 is not inclined relatively greatly with respect to the reference line RLN. In the horizontally mounted state, the inclination of the second straight line LN2 with respect to the vertical direction VD is greater than the inclination of the first straight line LN1 with respect to the vertical direction VD.

[0099] The second direction D2 is set appropriately in accordance with the second straight line LN2. For example, in FIG. 8, the second direction D2 is defined as a direction parallel to the second straight line LN2. The second direction D2 is defined, for example, as a direction along the second straight line LN2 that moves away from the base 55 toward the second side surface 51 shown in FIG. 7. The second direction D2 does not have to be parallel to the second straight line LN2. For example, the second direction D2 may be a straight line such that, when viewed from the axial direction AD, the angle formed between the second direction D2 and the second straight line LN2 is equal to or smaller than a predetermined threshold.

[0100] Because the second straight line LN2 does not incline relatively greatly with respect to the reference line RLN, the second direction D2 is defined by the second straight line LN2, and therefore the second connecting portion 52A can be arranged so that it faces in a direction close to the direction of the load L2 in the horizontal installation state. By being able to arrange the second connecting portion 52A so that it faces in a direction close to the direction of the load L2, stress concentration in the second connecting portion 52 can be alleviated.

[0101] (Variation) The description of each embodiment is merely an example of a form that the present invention can take, and is not intended to limit the present invention. For example, the present invention can take the form of a modified example of each embodiment shown below, or a combination of at least two modified examples that are not mutually contradictory.

[0102] For example, the configuration of the drive unit 29 in each embodiment is an example, and the drive unit 29 may include various devices not shown in each embodiment, or may be configured not to include some of the various devices shown in each embodiment.

[0103] For example, the drive unit 29 may further include an intermediate member that can be attached to both the housing 30 and the frame 11. When the drive unit 29 includes the intermediate member, at least one of the first connecting portion 42 and the second connecting portion 52 is attached to the intermediate member by at least one of the first fastener F1 and the second fastener F2. When the drive unit 29 includes the intermediate member, the frame 11 is connected to the intermediate member. By including the intermediate member in the drive unit 29, for example, when the first connecting hole 44 is not positioned coaxially with the first mounting hole 17b, the drive unit 29 can be attached to the frame 11 via the intermediate member.

[0104] For example, the second connecting hole 54 only needs to at least partially overlap the first connecting portion 42A when viewed from the axial direction AD, and does not need to be disposed coaxially with the first connecting hole 44 when viewed from the axial direction AD.

[0105] For example, the first connecting portion 42A may have a pair of first outer edge portions 47 that are symmetrical with respect to the first straight line LN1 when viewed in the axial direction AD. For example, the second connecting portion 52A may have a pair of second outer edge portions 57 that are asymmetrical with respect to the second straight line LN2 when viewed in the axial direction AD.

[0106] For example, the first direction D1 and the second direction D2 are not limited to the directions shown in FIGS. 5, 7, and 8. For example, the first direction D1 and the second direction D2 may be set to face in directions different from those in each embodiment depending on the direction of the reference line RLN. For example, in a horizontal mounting state, when the center C1 of the first connecting hole 44 is positioned above or below the rotation central axis RCA1, the reference line RLN is a line along the vertical direction VD. When the reference line RLN is a line along the vertical direction VD, the first line LN1 defining the first direction D1 may be parallel to the reference line RLN. When the reference line RLN is a line along the vertical direction VD, the second line LN2 defining the second direction D2 may be inclined with respect to the reference line RLN.

[0107] Depending on the positional relationship between the rotation center axis RCA1 and the center C1 of the first connecting hole 44, the first straight line LN1 and the second straight line LN2 may be inclined with respect to the reference straight line RLN so as to pass above the rotation center axis RCA1 when viewed from the axial direction AD.

[0108] The phrase "at least one" as used herein means "one or more" of the desired options. As an example, the phrase "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 phrase "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]

[0109] 1...human-powered vehicle, 24...front wheel, 25...rear wheel, 29...drive unit, 30...housing, 41, 51...two side surfaces, 41...first side surface, 42, 42A...first connecting portion, 44...first connecting hole, 46...tip portion, 47...pair of first outer edge portions, 52, 52a...second connecting portion, 52...second side surface, 54...second connecting hole, 56...tip portion, 57...pair of second outer edge portions, A1...first angle, A 2...second angle, AD...axial direction, AR1...input rotation shaft, AR2...output rotation shaft, C1...center, D1...first direction, D2...second direction, F1...first fastener, F2...second fastener, LN1...first straight line, LN2...second straight line, LN47...pair of first outer edge straight lines, LN57...pair of second outer edge straight lines, M...electric motor, RCA1...rotation center axis, RL...reference line, VD...vertical direction

Claims

1. A drive unit for a human-powered vehicle, a housing including two side surfaces in which a through hole is formed, a first connecting portion provided on one of the two side surfaces, and a second connecting portion provided on the other of the two side surfaces, wherein an input rotation shaft to which a manual drive force is input can be inserted into the through hole; the first connecting portion has a first connecting hole that penetrates in the axial direction of the input rotation shaft when the input rotation shaft is inserted through the through hole and is configured to be connected to a first fastener that attaches the first connecting portion to the human-powered vehicle, the second connecting portion at least partially overlaps the first connecting portion when viewed in the axial direction and has a second connecting hole configured to connect to a second fastener that attaches the second connecting portion to the human-powered vehicle; the first connecting portion is disposed so as to extend in a first direction from the one side surface when viewed in the axial direction, The second connecting portion is arranged to extend from the other side surface in a second direction different from the first direction when viewed in the axial direction.

2. 2. The drive unit according to claim 1, wherein the first connecting portion and the second connecting portion are attached to the human-powered vehicle by the first fastener and the second fastener, and when the human-powered vehicle is in a horizontal mounting state with all wheels in contact with the horizontal ground, the inclination of the first direction with respect to the vertical direction is different from the inclination of the second direction with respect to the vertical direction.

3. 3. The drive unit according to claim 2, wherein an output rotating shaft to which a manual driving force and a motor driving force from an electric motor disposed in the internal space of the housing can be disposed can be placed in the through hole on the other side surface.

4. the input rotation shaft has a rotation center axis, the first connecting hole and the second connecting hole are arranged coaxially when viewed from the axial direction, the first direction is defined by a first straight line that is inclined with respect to a reference line that passes through a center of the first connecting hole and the rotation central axis when viewed from the axial direction in the inserted state, the second direction is defined by a second straight line that is inclined with respect to the reference straight line when viewed from the axial direction; 4. The drive unit according to claim 3, wherein a first angle defined by the first straight line and the reference straight line is greater than a second angle defined by the second straight line and the reference straight line.

5. The drive unit according to claim 4 , wherein the difference between the first angle and the second angle is set within a range of 35 degrees to 45 degrees.

6. 5. The drive unit according to claim 4, wherein the first straight line is inclined with respect to the reference straight line so as to pass below the central axis of rotation when viewed from the axial direction in the horizontally mounted state and the inserted state.

7. The drive unit according to claim 4 , wherein the first straight line passes through a tip end of the first connecting portion and the first connecting hole when viewed in the axial direction.

8. The drive unit according to claim 4 , wherein the first straight line is a straight line that bisects the first connecting hole when viewed in the axial direction.

9. The drive unit according to claim 8 , wherein the first connecting portion has a pair of first outer edge portions that are symmetrical with respect to the first straight line when viewed in the axial direction.

10. The drive unit according to claim 9 , wherein a pair of first outer edge straight lines along the pair of first outer edge portions as viewed in the axial direction intersect with each other.

11. 5. The drive unit according to claim 4, wherein the second straight line is inclined with respect to the reference straight line so as to pass below the central axis of rotation when viewed from the axial direction in the horizontally mounted state and the inserted state.

12. The drive unit according to claim 4 , wherein the second straight line passes through a tip end of the second connecting portion and the second connecting hole when viewed in the axial direction.

13. The drive unit according to claim 4 , wherein the second straight line is a straight line that bisects the second connecting hole when viewed in the axial direction.

14. The drive unit according to claim 13 , wherein the second connecting portion has a pair of second outer edge portions that are symmetrical with respect to the second straight line when viewed in the axial direction.

15. The drive unit according to claim 14 , wherein a pair of second outer edge straight lines along the pair of second outer edge portions as viewed in the axial direction intersect with each other.

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