Drive unit cover for moving body

Abstract

This drive unit cover (30) for a moving body comprises: a side cover (40); an undercover (50) assembled, together with the side cover (40), to a motor bracket (10) or a drive unit (20); and a vent hole (31) formed in a portion covering the front surface of the drive unit (20). The side cover (40) has a cut-out (43) as an element constituting the vent hole (31), and the undercover (50) has a frame part (53). The vent hole (31) is formed at the boundary between the side cover (40) and the undercover (50) by combining the cut-out (43) and the frame part (53).

Description

Cover for drive unit of mobile device

[0001] The present invention relates to a cover for a drive unit of a moving object.

[0002] Electrically assisted bicycles, which provide assistance to the rider by providing auxiliary driving force from a motor in addition to the human driving force based on pedal force, are well known as vehicles equipped with a drive unit including a motor. Small vehicles that run solely on motor power, such as electric kick scooters, have also become popular in recent years. The drive units installed in such vehicles are typically fitted with a plastic cover to protect them from damage from external impacts and to improve their design.

[0003] For example, Patent Document 1 discloses a resin cover attached to the drive unit of an electrically assisted bicycle. The drive unit generates heat when driven because it needs to output power to propel the vehicle. Therefore, if the drive unit is covered with a cover, heat can accumulate inside the cover, causing the unit's temperature to rise and resulting in a decrease in performance. Furthermore, if the drive unit becomes too hot, problems such as deterioration of components and a shortened lifespan can occur. For this reason, the cover is provided with ventilation holes for cooling.

[0004] The cover disclosed in Patent Document 1 has multiple slits formed as cooling vents. The multiple slits formed in the cover facilitate contact of outside air with the drive unit, contributing to suppressing temperature increases in the motor. The slits are formed with a width of 10 mm or less to prevent a user's fingers from touching the drive unit through the slits.

[0005] JP 2011-35110 A

[0006] As described above, the cover disclosed in Patent Document 1 has many ventilation holes (slits), but forming many ventilation holes in the cover and increasing the opening area reduces the rigidity of the cover, making it more susceptible to deformation when subjected to external forces. On the other hand, reducing the number of ventilation holes and their size reduces the deformation of the cover, but makes it difficult to sufficiently suppress the temperature rise of the drive unit. In other words, it is not easy to realize a cover that contributes to suppressing the temperature rise of the drive unit while suppressing deformation due to external forces.

[0007] One aspect of the present invention is a cover for a drive unit of a movable body, which is a cover that covers the drive unit of a movable body, and comprises a first divided body, a second divided body that is assembled together with the first divided body to the drive unit or the movable body, and an air vent formed in a portion that covers the front of the drive unit, wherein the first divided body and the second divided body each have first and second elements that constitute the air vent, and the air vent is formed at the boundary between the first divided body and the second divided body by the combination of the first and second elements.

[0008] Another aspect of the present invention is a cover for a drive unit of a movable body, which is a cover that covers the drive unit of a movable body, and comprises a first divided body, a second divided body that is assembled to the drive unit or the movable body together with the first divided body, and an air vent formed in a portion that covers the front of the drive unit, wherein the front face of the second divided body has a shape that protrudes further forward than the front face of the first divided body toward the front of the movable body, and the air vent is formed on the front face of the first divided body, which is recessed further rearward than the front face of the second divided body.

[0009] The cover for a drive unit of a vehicle according to the present invention is resistant to deformation due to external forces, and contributes greatly to suppressing temperature increases in the drive unit. The cover according to the present invention is highly durable and can efficiently introduce outside air into the cover while the vehicle is moving.

[0010] 1 is a perspective view of a vehicle that is an example of an embodiment; FIG. 2 is a perspective view of a drive unit cover that is an example of an embodiment, as seen from the front left of the vehicle, showing a state in which the cover is assembled to the drive unit and a motor bracket (drive unit assembly); FIG. 3 is a perspective view of the drive unit cover as seen from the rear left of the vehicle, showing a state in which the cover is assembled to the drive unit and a motor bracket; FIG. 4 is an exploded perspective view of a drive unit assembly; FIG. 5 is a perspective view of a side cover and an under cover that constitute the drive unit cover; FIG. 6 is a view in which the cover is cut at a portion in FIG. 2 where an air vent is formed; FIG. 7 is a view showing the flow of air introduced into the cover from the air vent when the vehicle is running; FIG. 8 is a view for explaining the mounting structure of the side cover to the drive unit and the motor bracket; and FIG. 9 is a view showing the alignment structure of a stator cover that constitutes the drive unit cover with respect to the drive unit.

[0011] Hereinafter, with reference to the drawings, an embodiment of a drive unit cover for a moving body according to the present invention will be described in detail. The embodiment described below is merely an example, and the present invention is not limited to the following embodiment. Furthermore, forms obtained by selectively combining multiple embodiments and modified examples described below are included within the scope of the present invention.

[0012] 1 is a diagram showing the appearance of a vehicle 1 equipped with a drive unit cover 30, which is an example of an embodiment. In this specification, terms indicating front-rear, up-down, and left-right directions are used, and the terms front-rear, up-down, up-down, and left-right of the vehicle 1 and each component refer to the front-rear, up-down, up-down, and left-right directions of the vehicle 1 and each component in a normal use state of the vehicle 1. Left and right refer to the left and right directions as viewed from the front (direction of travel) of the vehicle 1. Furthermore, the front surface of the drive unit cover 30 and the like refers to the surface facing forward of the vehicle 1, and the rear surface refers to the surface facing rearward of the vehicle 1.

[0013] In this embodiment, a vehicle 1 shown in FIG. 1 is used as an example of a mobile body equipped with a drive unit, but the mobile body is not limited to the vehicle 1. The drive unit cover according to the present invention can also be applied to other mobile bodies besides the vehicle 1. Examples of other mobile bodies include electric vehicles similar to bicycles and motorcycles, stand-up electric vehicles such as electric kick scooters, and electric wheelchairs. The electric vehicle may be a vehicle classified as a specified small motorized bicycle or a special specified small motorized bicycle under the Road Traffic Act, or may be a vehicle capable of running by switching driving modes.

[0014] As shown in FIG. 1 , vehicle 1 is an electrically assisted bicycle equipped with pedals 7 for applying human-powered driving force and a drive unit 20 including a motor. Vehicle 1 further includes a battery 8 for supplying power to drive unit 20. Vehicle 1 is configured to assist driving by applying auxiliary driving force from the motor to the human-powered driving force based on the force applied to pedal 7. Note that the driving modes of vehicle 1 may be set to a self-propelled mode in which vehicle 1 travels using only the driving force of the motor, a push-walk mode in which auxiliary driving force from the motor is applied when the vehicle is pushed, or the like. Vehicle 1 may also include an operating unit for adjusting the output of the motor, such as an accelerator grip or an accelerator lever.

[0015] Similar to a typical bicycle, the vehicle 1 includes a frame 2, a front wheel 3a, a rear wheel 3b, handlebars 4 including brakes, a saddle 5, crank arms 6, pedals 7, and a chain (not shown). The frame 2 is a framework connecting the front wheel 3a, the rear wheel 3b, the handlebars 4, the saddle 5, and the like, and is composed of multiple tubes. In this embodiment, the multiple tubes include a head tube 2a, a front fork 2b, a down tube 2c, a seat tube 2d, a top tube 2e, a chainstay 2f, and a seat stay 2g. The crank arms 6 are fixed to both ends of an output shaft 24 of the drive unit 20 (see FIG. 2, etc., described below). A front sprocket 28 is attached to the output shaft 24. The battery 8 is attached to the down tube 2c and can be removed by unlocking it.

[0016] The vehicle 1 further includes a motor bracket 10 to which the drive unit 20 is fixed, and a drive unit cover 30 (hereinafter simply referred to as "cover 30"). The cover 30 is a resin cover that covers the drive unit 20 and is composed of first and second separate bodies that can be separated from each other. As will be described in detail below, the cover 30 has a side cover 40 that is the first separate body, and an undercover 50 that is the second separate body that is attached to the motor bracket 10 or the drive unit 20 together with the side cover 40. The motor bracket 10 forms part of the frame 2 and functions as a fixing member for the drive unit 20 and as a connecting member for connecting the down tube 2c and the seat tube 2d.

[0017] In this embodiment, the side cover 40 is fixed to the drive unit 20, and the under cover 50 is fixed to the motor bracket 10. The side cover 40 and the under cover 50 can be fixed separately to their respective fixing targets. In other words, the order in which the side cover 40 and the under cover 50 are attached is not limited, and it is also possible to remove only one of them. The cover 30 further has a stator cover 60, which is a third divided body. Hereinafter, an assembly in which the cover 30 is attached to the motor bracket 10 or the drive unit 20 will be referred to as a "drive unit assembly."

[0018] The vehicle 1 further includes a switch unit 9. The switch unit 9 is generally called a hand switch and is installed on the handlebars 4. The switch unit 9 has operating elements such as a power switch and an assist level selector switch. When the power switch is turned on, the drive unit 20 starts up and the vehicle enters an assisted driving mode using motor power or a self-propelled mode in which the vehicle travels solely using motor power. An operating element for executing the push-walking mode and a display element such as an LCD monitor may be provided on or near the switch unit 9. The vehicle 1 may also include safety components such as headlights, taillights, direction indicators, and a maximum speed indicator.

[0019] The configuration of the drive unit cover 30 and the drive unit assembly will be described in detail below with reference to FIGS.

[0020] 2 and 3 are perspective views of the drive unit assembly. Fig. 4 is an exploded perspective view of the drive unit assembly. For clarity of illustration, in Fig. 4, the bolts 29 are shown fastened to the first fixing portion 25 of the drive unit 20. The bolt reference numerals and the circuit board 23 are only shown in Fig. 4. Fig. 5 is a perspective view of the side cover 40 and the under cover 50, and will be referred to as appropriate.

[0021] 2 to 4, the cover 30 includes a side cover 40, an under cover 50, and a stator cover 60, and covers the drive unit 20 fixed to the motor bracket 10. A portion of the drive unit 20 is housed within the motor bracket 10, but most of the drive unit 20 is exposed from the motor bracket 10, and the exposed portion is covered by the cover 30. The cover 30 protects the drive unit 20 to prevent damage, and also hides the drive unit 20 to improve the design of the vehicle 1. The thickness of the cover 30 is, for example, not less than ** mm and not more than ** mm.

[0022] The cover 30 is fixed to the motor bracket 10 or the drive unit 20 to form a drive unit assembly. Because the motor bracket 10 houses a portion of the drive unit 20, it can be said that the cover 30 covers the drive unit 20 together with the motor bracket 10. The motor bracket 10 mainly covers the top and rear surfaces of the drive unit 20, the side cover 40 covers the left side surface and front surface of the drive unit 20, and the under cover 50 covers the bottom and front surface of the drive unit 20. On the other hand, most of the right side surface of the drive unit 20 is exposed and not covered by the cover 30, and is covered by the front sprocket 28.

[0023] The motor bracket 10 is a component that constitutes part of the frame 2 and is made of the same material as the other parts of the frame. The motor bracket 10 is made of a metal material, such as aluminum, an aluminum alloy, or stainless steel. The motor bracket 10 has an internal space that can accommodate part of the drive unit 20. The motor bracket 10 includes a first portion formed in a rectangular cylindrical shape and a second portion that extends from the first portion toward the rear of the vehicle 1 and curves downward as it approaches the rear end, and covers the top and rear surfaces of the drive unit 20.

[0024] The motor bracket 10 is preferably welded to the down tube 2c and the seat tube 2d (see FIG. 1). The motor bracket 10 has a first opening 11 formed in the first portion and a second opening 12 formed in the second portion, and is welded to each tube with the first opening 11 connected to the interior space of the down tube 2c and the second opening 12 connected to the interior space of the seat tube 2d. For example, rainwater or the like may seep into the interior of the seat tube 2d. The rainwater passes through the second opening 12, inside the cover 30, and is then discharged from a through-hole 52 in the undercover 50 (described later).

[0025] The motor bracket 10 has a unit fixing portion 13 to which the drive unit 20 is fixed and a cover fixing portion 14 to which the cover 30 is fixed. The unit fixing portion 13 includes insertion holes for bolts 29 that are fastened to the first fixing portion 25 of the drive unit 20, and multiple unit fixing portions 13 are provided on each of the left and right sides of the motor bracket 10. Specifically, the motor bracket 10 has unit fixing portions 13 at the front end, rear end, and three locations in between, for a total of six locations on the left and right sides. The unit fixing portions 13 include recesses that are recessed inward and can accommodate the heads of the bolts 29. The cover fixing portions 14 are portions to which the undercover 50 is fixed, and are provided at the front and rear ends of the motor bracket 10.

[0026] The drive unit 20 includes a unit body 21 containing a motor, a circuit board 23, a drive mechanism for transmitting the power of the motor to the output shaft 24, and the output shaft 24 protruding in the left-right direction from the unit body 21. The unit body 21 includes a case that houses the motor and other components. The case is made of a metal such as aluminum or an alloy. Crank arms 6 are attached to both ends of the output shaft 24, and the force applied to the pedals 7 is transmitted to the rear wheel 3b via the crank arms 6, the output shaft 24, a front sprocket 28, and a chain (not shown). The power of the motor is also transmitted to the rear wheel 3b via the output shaft 24, the front sprocket 28, and the chain.

[0027] The motor may be any electric motor capable of driving the vehicle 1 using power supplied from the battery 8. An example of such a motor is a three-phase brushless DC motor. The circuit board 23 includes, for example, a control circuit that comprehensively controls the operation of the vehicle 1, and a drive circuit that controls the current supplied to the motor based on control signals output from the control circuit. The amount of current supplied to the motor is changed by the switching operation of the drive circuit, thereby controlling the output of the motor. The drive mechanism includes, for example, a reducer, a clutch, etc. The unit body 21 may also include various sensors built in, such as a rotation sensor, a torque sensor, a temperature sensor, and an acceleration sensor.

[0028] The front surface of the unit body 21 is greatly curved so as to convex toward the front of the vehicle 1, and is formed in an arc shape in a side view. A motor is disposed in the front portion of the unit body 21, and the outer shape of the unit body 21 is formed in a cylindrical shape corresponding to the stator of the motor. In this embodiment, the portion where the motor stator is disposed and having a shape corresponding to the stator is referred to as a "stator portion 22." In the front portion of the unit body 21, a convex portion 21a is formed in the left-right central portion, which protrudes forward and up and down more than both end portions, and a step is formed between the convex portion 21a (left-right central portion) and both left-right end portions.

[0029] The stator portion 22 is formed to protrude toward the left side of the vehicle, and the bottom surface of the cylinder of the stator portion 22 forms the left side of the unit body 21. Furthermore, a portion of the outer peripheral surface of the cylinder of the stator portion 22 forms the front surface of the stator portion 22 facing forward of the vehicle. The front surface of the stator portion 22 is located further rearward than the front surface of the convex portion 21a, and the lower end of the stator portion 22 is also located further upward than the convex portion 21a. In other words, the outer peripheral surface of the stator portion 22 is located further back than the convex portion 21a, and is therefore less susceptible to external impacts. Note that the stator portion 22 is a portion of the drive unit 20 that generates particularly large amounts of heat, so it is preferable that the cover 30 be configured to allow outside air to efficiently reach the stator portion 22.

[0030] An output shaft 24 is attached to the rear portion of the unit body 21, and a circuit board 23 is also disposed thereon. The portion of the case of the unit body 21 that is positioned around the output shaft 24 protrudes toward the left side of the vehicle, similar to the stator portion 22. A portion of the circuit board 23 is exposed from the case at the bottom of the unit body 21, and a cable connection portion is provided on this exposed portion of the circuit board 23. The cable connected to the circuit board 23 is introduced, for example, from inside the down tube 2c through the first opening 11 of the motor bracket 10 and into the cover 30. As will be described in detail later, a space for routing the cable is provided between the surface of the unit body 21 and the rear surface of the side cover 40.

[0031] The drive unit 20 further has a first fixing portion 25 that is fixed to the motor bracket 10 and a second fixing portion 26 to which the cover 30 is fixed. The first fixing portions 25 are formed in three locations on both the left and right sides of the unit main body 21: the front end, the top end, and the rear end. The first fixing portions 25 are portions that protrude from the unit main body 21 and include bolt holes into which bolts 29 are fastened. The first fixing portions 25 are fixed to the motor bracket 10 using the bolts 29 that are inserted into the unit fixing portions 13 of the motor bracket 10.

[0032] The second fixing portion 26 is a portion used to fix the side cover 40, and is formed on the left side surface of the unit main body 21. The second fixing portion 26 includes a bolt hole into which a bolt 48 is fastened. The side cover 40 is fixed to the drive unit 20 using a bolt 48 that is inserted through the fixing portion 44 of the cover and fastened to the second fixing portion 26. The second fixing portion 26 is formed in two locations, one above the other, in the center of the front-rear direction of the unit main body 21. The second fixing portion 26 is formed in a boss shape that protrudes toward the left side of the vehicle, and can support the side cover 40 while maintaining a gap between it and the case surface of the unit main body 21. This ensures a space for routing the above-mentioned cables behind the side cover 40.

[0033] As described above, the cover 30 includes the side cover 40, which is the first divided body, the under cover 50, which is the second divided body, and the stator cover 60, which is the third divided body. These three members that make up the cover 30 are independently detachable from the motor bracket 10 or the drive unit 20. The side cover 40 covers the left side surface, front surface, and bottom surface of the drive unit 20, and the under cover 50 covers the bottom surface and front surface of the drive unit 20. The bottom surface and front surface of the drive unit 20 are largely covered by the under cover 50, but the bottom surface and the portion of the front surface near the left side surface are covered by the side cover 40.

[0034] The cover 30 has air vents 31 formed in a portion covering the front of the drive unit 20. Because the air vents 31 open toward the front of the vehicle 1, outside air can be efficiently introduced into the cover 30 while the vehicle is moving. The outside air introduced through the air vents 31 directly hits the drive unit 20, thereby effectively cooling the drive unit 20. As will be described in detail below, the side cover 40 and the undercover 50 each have first and second elements that constitute the air vents 31, and the air vents 31 are formed at the boundary between the side cover 40 and the undercover 50 by combining the first and second elements.

[0035] The stator cover 60, which covers the left side of the drive unit 20 together with the side cover 40, has a circular shape in a side view. For example, letters and marks indicating the manufacturer's name, product name, etc. are displayed on the surface of the stator cover 60 (see FIG. 4 ). The stator cover 60 has an alignment mechanism (see FIG. 9 , described later) that allows the mounting angle to be adjusted, and the stator cover 60 can be mounted to the drive unit 20 so that the letters and marks on the surface are horizontal. Because the side cover 40 and the stator cover 60 are separate, the mounting angle of the stator cover 60 can be adjusted without being affected by the inclination of the side cover 40, which is fixed to the motor bracket 10 via the drive unit 20. The stator cover 60 is fixed to the stator portion 22 of the drive unit 20 using, for example, double-sided tape, but can also be fixed to the drive unit 20 using fastening members such as bolts.

[0036] As shown in FIGS. 2 to 5 , the side cover 40 has a shape corresponding to the left portion of the drive unit 20, is longer in the front-to-rear direction than in the up-to-down direction, and has curved front and rear ends that are convex in the front-to-rear direction. The side cover 40 is preferably made of a resin material from the standpoints of moldability, light weight, and the like. Examples of suitable resins for the side cover 40 include polycarbonate and ABS resin. The resin for the side cover 40 may contain pigments such as carbon black and various other additives. The undercover 50 and the stator cover 60 may also be made of, for example, the same material as the side cover 40. Furthermore, the three components may be made of metals such as aluminum, aluminum alloys, and stainless steel, taking heat dissipation into consideration.

[0037] The side cover 40 has a first opening 41 into which the stator cover 60 fits and a second opening 42 through which the output shaft 24 passes. The first opening 41 has a diameter slightly larger than that of the stator cover 60 so that the side cover 40 and the stator cover 60 do not interfere with each other. This allows the side cover 40 and the stator cover 60 to be attached and detached independently from the drive unit 20. Furthermore, because the drive unit 20 has an output shaft 24 extending from the unit main body 21 to the left side of the vehicle 1, the side cover 40, which covers the left side of the drive unit 20, must be formed with a second opening 42, which is a shaft hole through which the output shaft 24 passes. The second opening 42 is smaller than the first opening 41 and is formed rearward of the first opening 41 and aligned with the first opening 41 in the front-to-rear direction.

[0038] The side cover 40 has a stator housing 46 that houses the stator portion 22 of the drive unit 20. The stator housing 46 is cylindrically formed around the first opening 41 and covers the outer peripheral surface and the peripheral edge of the bottom surface of the columnar stator portion 22. The bottom surface of the stator portion 22 forms the left side surface of the unit main body 21, most of which is covered by a stator cover 60. The stator housing 46 is formed large in the front portion of the side cover 40, extending from the front end to the center in the longitudinal direction, and protrudes further to the left of the vehicle than the rear portion.

[0039] Similar to the stator housing 46, the side cover 40 has a shape in which the peripheral edge of the second opening 42, which is an axial hole through which the output shaft 24 passes, protrudes toward the left side of the vehicle. Note that the peripheral edge of the second opening 42 is susceptible to external impact. For this reason, in this embodiment, the peripheral edge of the second opening 42 protrudes in the direction in which the output shaft 24 extends beyond the portion where the fixing portion 44 to the drive unit 20 is formed, thereby increasing the rigidity of the side cover 40. The rear portion of the side cover 40, which is located rearward of the stator housing 46, has a raised shape from the peripheral edge of the second opening 42 to the stator housing 46.

[0040] The rear portion of the side cover 40 includes a first region 47a that protrudes from the peripheral edge of the output shaft 24 to the stator housing portion 46, a second region 47b that is formed in a generally U-shape surrounding three sides of the first region 47a in a side view, and a third region 47c that is formed at the lower end of the side cover 40. The rear portion of the side cover 40 has a multi-step shape in which the heights from the surface of the unit body 21 gradually decrease in the order of the first region 47a, the second region 47b, and the third region 47c. This multi-step shape increases the rigidity and durability of the side cover 40.

[0041] The second region 47b of the side cover 40 is formed in a generally U-shape in side view, forming a gap between it and the surface of the unit body 21. The third region 47c, which has the lowest height, is small and formed between the second region 47b and the stator housing portion 46 at the lower end of the side cover 40. The second region 47b is disposed in a position facing the circuit board 23 of the drive unit 20, thereby ensuring a routing space on the back side of the side cover 40 for cables connected to the circuit board 23. For example, the cables extend upward along the second region 47b, which is formed in a generally U-shape in side view, and pass through the motor bracket 10 and the inside of the down tube 2c to be connected to the battery 8, switch unit 9, etc.

[0042] The side cover 40 has a fixing portion 44 that is fixed to the drive unit 20, and an engagement claw 45 that hooks onto the back surface of the motor bracket 10. As will be described in detail below, the engagement claw 45 is formed on the upper front side of the side cover 40 and hooks onto the motor bracket 10 to prevent the cover from lifting up. The side cover 40 is also supported from the back side by support claws 15 formed on the motor bracket 10. The fixing portions 44 are formed in two locations, one above and one below, at the center of the side cover 40 in the fore-and-aft direction or slightly rearward of the center. The side cover 40 is fixed to the drive unit 20 only with two bolts 48 attached to the fixing portions 44.

[0043] The fixing portion 44 is formed at a position overlapping the second fixing portion 26 of the drive unit 20 and includes an insertion hole for the bolt 48. The fixing portion 44 is formed in a cylindrical shape with a bottom that protrudes toward the rear side, and the head of the bolt 48 can be accommodated within the cylinder. An insertion hole for passing the shaft of the bolt 48 is formed in the bottom of the cylinder of the fixing portion 44. The fixing portion 44 located at the top of the side cover 40 is formed in the second region 47b, and the fixing portion 44 located at the bottom is formed in the third region 47c. The third region 47c is formed only around the fixing portion 44. The two fixing portions 44 are disposed near the stator accommodating portion 46 and do not interfere with the routing of the cables.

[0044] The side cover 40 has a notch 43 formed therein as the first element constituting the air vent 31. The notch 43 is a cylindrical wall of the stator housing portion 46, which is formed in a cylindrical shape, and is formed in a portion of the front surface of the side cover 40 facing forward. That is, the notch 43 is formed in a portion of the portion covering the front surface of the stator portion 22 of the drive unit 20. The notch 43 can be formed by cutting out a portion of the molded cover, but from the standpoints of reducing manufacturing costs and improving the appearance of the cover, it is preferable to mold the notch 43 integrally with the other portions of the side cover 40 using a mold. The side cover 40 is manufactured by injection molding using, for example, polycarbonate, ABS resin, or the like.

[0045] The notch 43 is formed to be longer in the circumferential direction than in the axial direction of the stator accommodating portion 46. In this case, it is possible to efficiently direct the outside air introduced from the front of the vehicle over a wide area of ​​the front surface of the stator portion 22 while suppressing a decrease in the rigidity of the side cover 40. As will be described in detail later, the frame portion 53 of the undercover 50 fits into the notch 43 to form the vent hole 31, and therefore the width and length of the notch 43 are greater than the width and length of the opening of the vent hole 31.

[0046] The notch 43 is formed with a width that extends from one axial end of the stator accommodating portion 46 near the surface of the unit body 21, but does not reach the first opening 41 at the other axial end. Two edges of the notch 43 extending in the axial direction of the stator accommodating portion 46 are inclined with respect to the axial direction so that the length of the notch 43 along the circumferential direction of the stator accommodating portion 46 gradually decreases toward the other axial end (the first opening 41 side). In other words, the notch 43 has a tapered shape that tapers slightly toward the first opening 41 side, and is formed in a substantially trapezoidal shape. This makes it easy to suppress a decrease in the rigidity of the side cover 40 and also makes it easier to insert the frame portion 53.

[0047] The undercover 50 is elongated in the front-to-rear direction to widely cover the bottom and front of the drive unit 20, and has an overall curved shape resembling the bottom of a boat. The undercover 50 has a central portion in the front-to-rear direction or a portion slightly rearward thereof that is the lowest point of the drive unit assembly, and curves upward gradually toward the front and rear ends. In particular, the front portion of the cover is significantly curved so that the front end of the undercover 50 is positioned at the highest point. The undercover 50 has fixing portions 51 that are fixed to the motor bracket 10, and the fixing portions 51 are formed at the front and rear ends of the undercover 50.

[0048] The undercover 50 is fixed at its front and rear ends to the cover fixing portions 14 of the motor bracket 10 using two bolts 54 each. The fixing portions 51 have insertion holes for the bolts 54 that are fastened to the cover fixing portions 14. The undercover 50 is not fixed to the drive unit 20 or the side covers 40, but is fixed to the motor bracket 10 only by the fixing portions 51 at its front and rear ends. Therefore, the undercover 50 can be removed independently while the side covers 40 remain attached to the drive unit 20.

[0049] The undercover 50 has a through hole 52 formed in a portion of the cover 30 that is positioned rearward of the air vent 31 of the cover 30. The through hole 52 functions as a drain port for discharging rainwater and the like that has seeped into the cover 30, and also functions as an exhaust port for discharging outside air that has been introduced through the air vent 31 and used to cool the motor. In this embodiment, the through hole 52 is formed rearward of the stator portion 22. The through hole 52 is formed longer in the front-to-rear direction than in the left-to-right direction, and at least a portion of it is located at the lowest point of the undercover 50. By having the through hole 52 located at the lowest point of the undercover 50 when the undercover 50 is assembled to the vehicle 1, rainwater and the like can be efficiently discharged without remaining inside the undercover 50.

[0050] In order to miniaturize the drive unit assembly, it is preferable that the undercover 50 has a shape that conforms as closely as possible to the front and bottom surfaces of the unit main body 21. Because a convex portion 21a is formed in the left-right center portion of the unit main body 21, the left-right center portion of the front surface of the undercover 50 has a shape that convexes outward more than the other side portions. In other words, the left portion of the front surface of the undercover 50, which covers the front surface of the stator portion 22 together with the side cover 40, is located further rearward of the vehicle than the left-right center portion. It is preferable that the undercover 50 wraps around the right side surface of the drive unit 20 and covers part of the right side surface.

[0051] The undercover 50 has a frame portion 53, as the second element constituting the vent hole 31, that is formed to outline the vent hole 31 and fits into the cutout 43 of the side cover 40. The frame portion 53 preferably fits snugly into the cutout 43, has a shape corresponding to the cutout 43, and has substantially the same outer dimensions as the cutout 43. The frame portion 53 is formed by protruding a portion of the undercover 50 to the left side of the vehicle at a position opposite the front surface of the stator portion 22, and its outer shape has a tapered shape that tapers slightly toward the tip. This allows the frame portion 53 to be smoothly inserted into the cutout 43, improving the ease of assembling the cover 30.

[0052] The frame portion 53 is formed in a rectangular frame shape that extends longer in the circumferential direction than in the axial direction of the stator portion 22. Note that the vent hole 31 is formed by fitting into the cutout 43, and the opening surrounded by the frame portion 53 is the opening of the vent hole 31 that essentially passes outside air. The frame portion 53 forms the periphery of the vent hole 31 and has a substantially constant width over its entire length. The frame portion 53 is preferably molded integrally with the other portions of the undercover 50. Like the side covers 40, the undercover 50 is manufactured by injection molding using polycarbonate, ABS resin, or the like.

[0053] The air vent 31 is formed in a portion of the front surface of the cover 30 that is recessed further rearward than the front end of the cover 30. The left-right central portion of the front surface of the undercover 50 protrudes forward of the vehicle to form the front end of the cover 30, and the front surface of the side cover 40 and the left portion of the front surface of the undercover 50 are recessed from the front end of the cover 30 and are positioned further rearward than the front end. A notch 43 that forms the air vent 31 is formed in the front surface of the side cover 40, and a frame portion 53 that forms the air vent 31 is formed in the left portion of the front surface of the undercover 50. Although forming an air vent reduces the rigidity of the cover, in this embodiment, no air vent is formed in the front end of the cover 30, which is susceptible to external impacts. Instead, the air vent 31 is formed in a portion recessed rearward of the vehicle that is less susceptible to external impacts. As a result, deformation of the cover 30 is effectively suppressed.

[0054] As described above, when the side cover 40 is fixed to the drive unit 20 and the under cover 50 is fixed to the motor bracket 10, the frame portion 53 fits into the notch 43, and the vent hole 31 is formed at the boundary between the side cover 40 and the under cover 50. If a vent hole were formed in only one of the covers, the rigidity of that cover would be significantly reduced, but in this embodiment, by forming elements that constitute the vent hole 31 in both covers, this localized significant reduction in the rigidity of the covers is prevented. As a result, sufficient rigidity can be ensured for the entire cover.

[0055] Although the ventilation hole 31 can be formed by arranging the frame portion 53 so that it overlaps the peripheral edge of the cutout 43, it is preferable that the frame portion 53 is formed so that it fits snugly inside the cutout 43. Also, it is preferable that the surfaces of the side cover 40 and the under cover 50 are approximately flush around the ventilation hole 31. In this case, there are no steps that could cause snagging, improving the durability of the cover. The frame portion 53 reinforces the peripheral edge of the cutout 43, effectively preventing a decrease in the rigidity of the cover due to the formation of the ventilation hole 31.

[0056] The maximum width of the opening of the ventilation hole 31 is preferably greater than 10 mm, and particularly preferably greater than 10 mm and not greater than 13 mm. Here, the width of the ventilation hole 31 refers to the length of the opening of the ventilation hole 31 along the axial direction of the stator housing portion 46. If the opening width of the ventilation hole 31 is greater than 10 mm and not greater than 13 mm, it is easy to introduce outside air into the cover 30 while suppressing a decrease in the rigidity of the cover 30. Furthermore, if the opening width of the ventilation hole 31 is greater than 10 mm, for example, if dust is trapped between the drive unit 20 and the cover 30, the dust can be removed without removing the cover 30. For the same reasons, the maximum width (maximum length in the left-right direction) of the opening of the through-hole 52 is also preferably greater than 10 mm, and particularly preferably greater than 10 mm and not greater than 13 mm.

[0057] The cover 30 will be further described below with reference to FIGS.

[0058] FIG. 6 is a cross-sectional view of the cover 30 at the portion where the ventilation hole 31 is formed. As shown in FIG. 6 , the clearance α between the peripheral edge of the ventilation hole 31 and the stator portion 22 is preferably small, specifically, preferably 5.0 mm or less, and more preferably 4.0 mm or less. An example of a suitable range for the clearance α is 1.0 mm or more and 5.0 mm or less, or 2.0 mm or more and 4.0 mm or less. In this case, it is possible to prevent fingers from getting caught between the cover 30 and the stator portion 22 or to prevent dust from getting stuck between the cover 30 and the stator portion 22. Furthermore, by reducing the clearance α, it is possible to prevent objects from getting caught on the peripheral edge of the ventilation hole 31 and improve the durability of the cover 30.

[0059] The frame portion 53 of the undercover 50 preferably has a slope that is inclined so as to approach the stator portion 22 toward the inside of the air vent 31. In this embodiment, the clearance α between the back surface of the frame portion 53 and the stator portion 22 is substantially constant. That is, a slope is formed on the surface of the frame portion 53 such that the thickness of the frame portion 53 gradually decreases toward the inside of the air vent 31. The slope on the surface of the frame portion 53 is preferably formed around the entire circumference of the air vent 31. Forming a slope on the surface of the frame portion 53 makes it easier to introduce wind coming from the front of the vehicle into the cover 30. In addition, the reduced step at the periphery of the air vent 31 reduces the occurrence of snagging, contributing to improved durability of the cover 30.

[0060] FIG. 7 is a diagram showing the flow of air introduced into the cover 30 through the air vent 31 (not shown in FIG. 7 ) while the vehicle is running. As shown in FIG. 7 , the cover 30, through the air vent 31 and the through-holes 52, can efficiently introduce outside air into the cover while the vehicle is running, and can smoothly exhaust the outside air that has cooled the drive unit 20 from the cover. The air vent 31 opens toward the front of the vehicle and is formed in front of the stator portion 22, which generates a large amount of heat. Therefore, the outside air introduced through the air vent 31 directly hits the stator portion 22 while the vehicle is running. Furthermore, the through-hole 52 is formed at the lowest point of the cover 30, further rearward of the stator portion 22, so that the outside air that has cooled the stator portion 22 is smoothly exhausted without stagnating within the cover 30.

[0061] The air vent 31 is formed in a position facing the outer peripheral surface of the stator portion 22 and slightly below the center of the stator portion 22 in the up-down direction. The cover 30 is also formed to fit along the outer peripheral surface of the stator portion 22 with a small gap between it and the outer peripheral surface. Therefore, after hitting the outer peripheral surface of the stator portion 22, outside air introduced into the cover 30 through the air vent 31 flows along the outer peripheral surface toward the rear of the vehicle and is exhausted through the through-holes 52 located behind the stator portion 22. The cover 30 allows outside air to hit a wide area of ​​the outer peripheral surface of the stator portion 22 and cools the stator portion 22, allowing the outside air whose temperature has risen to be smoothly exhausted.

[0062] FIG. 8 is a diagram illustrating the mounting structure of the side cover 40. As shown in FIG. 8, the motor bracket 10 is formed with support claws 15 that support the side cover 40 from the back side. The side cover 40 is disposed on the support claws 15 and has engagement claws 45 that hook onto the back surface of the motor bracket 10. The side cover 40 is supported by and engaged with the motor bracket 10, but is not fixed to the motor bracket 10 or the undercover 50 with bolts; it is fixed to the drive unit 20 only by the fixing portions 44. Therefore, the side cover 40 can be removed independently while the undercover 50 remains attached to the motor bracket 10.

[0063] The support claws 15 of the motor bracket 10 are protrusions formed on the left side of the motor bracket 10 and are large enough to support the side cover 40 from the back side. Two support claws 15 are formed on the rear side of the motor bracket 10, between the two unit fixing portions 13. The rear end of the side cover 40 is raised above the surface of the unit main body 21 because a space for passing cables is formed between the side cover 40 and the unit main body 21. For this reason, it is preferable to position the rear end of the side cover 40 on the support claws 15 to prevent the cover from sinking.

[0064] The engagement claw 45 of the side cover 40 is a protrusion formed on the front side of the side cover 40 and is sized to engage with the back surface of the motor bracket 10. One engagement claw 45 is formed at the front end of the side cover 40, adjacent to the unit fixing portion 13. A stator accommodating portion 46 that covers the bottom surface of the stator portion 22 is formed in the front portion of the side cover 40, so that the side cover 40 is supported from the back side by the stator portion 22 and does not sink. Meanwhile, the front end of the side cover 40 is farther from the fixing portion 44 than the rear end. For this reason, it is preferable to hook the engagement claw 45 onto the back surface of the motor bracket 10 to prevent the side cover 40 from lifting up.

[0065] 9 is a diagram showing the alignment structure of the stator cover 60 relative to the drive unit 20. As shown in FIG. 9, a plurality of alignment protrusions 27a are formed on the bottom surface of the stator portion 22, and a plurality of alignment grooves 61a are formed on the back surface of the stator cover 60. A large number of alignment grooves 61a are formed in an annular shape, and by fitting the alignment protrusions 27a into the desired groove, the stator cover 60 can be attached at a desired angle relative to the drive unit 20. As described above, letters, marks, etc. indicating the manufacturer name, product name, etc. are displayed on the surface of the stator cover 60, and the stator cover 60 can be attached so that these letters, etc. are horizontal.

[0066] An annular recess 27b is formed on the bottom surface of the stator portion 22, and six alignment protrusions 27a are formed at equal intervals within the recess 27b. An annular protrusion 61b is formed on the back surface of the stator cover 60, and multiple alignment grooves 61a are formed at equal intervals within the protrusion 61b. The alignment grooves 61a are formed, for example, at intervals of approximately 10° relative to the center of the protrusion 61b. The stator cover 60 is fixed to the stator portion 22 by inserting the protrusions 61b into the recess 27b, fitting the alignment grooves 61a into the alignment protrusions 27a, adjusting the angle of the characters on the cover surface, and then firmly pressing the cover against the bottom surface of the stator portion 22. The method for fixing the stator cover 60 to the bottom surface of the stator portion 22 is not particularly limited, but in this embodiment, double-sided tape is used.

[0067] As described above, the drive unit assembly having the above configuration makes it difficult for the cover 30 to deform due to external forces, and effectively suppresses temperature increases in the drive unit 20. The cover 30 is highly durable and can efficiently introduce outside air into the interior while the vehicle is running.

[0068] Because the ventilation holes 31 in the cover 30 are formed in front of the stator portion 22, outside air efficiently hits the front surface of the stator portion 22, and the outside air that has cooled the stator portion 22 is smoothly exhausted through the through holes 52 in the undercover 50 formed behind the stator portion 22. This smooth flow of outside air efficiently cools the stator portion 22, so even with only one ventilation hole 31, it is possible to effectively suppress a rise in temperature of the drive unit 20. Furthermore, by forming the ventilation holes 31 using the notches 43 in the side covers 40 and the frame portion 53 of the undercover 50, the durability of the entire cover can be improved.

[0069] The above-described embodiment may be modified in design without departing from the scope of the present invention. For example, in the above-described embodiment, the cover 30 is configured from three separate sections, including the side cover 40, the undercover 50, and the stator cover 60. However, the stator cover 60 may be integrated with the side cover 40. In this case, the side cover does not have the first opening 41 and covers the bottom surface of the stator portion 22. Another example of the drive unit cover may be configured only with a first separate section having a notch and a second separate section having a frame portion. When a stator cover separate from the side cover is provided, the stator cover may be fixed to the stator portion first, and then the side cover may be fixed. In this case, the side cover can prevent the stator cover from falling off.

[0070] In the above embodiment, most of the front surface of the undercover 50, which is the second segment, protrudes further forward than the front surface of the side cover 40, which is the first segment. In other words, the front surface of the side cover 40 is recessed further rearward than the front surface of the undercover 50, making it less susceptible to external impacts. In this case, air vents may be formed only on the front surface of the first segment. Even if the rigidity of the first segment is reduced by the air vents, the first segment is less susceptible to external impacts than the second segment, making it less likely to deform. However, forming air vents in both the first and second segments can more reliably suppress deformation of the cover.

[0071] The present invention is further described by the following embodiments. Configuration 1: A cover for a drive unit of a movable body, the cover comprising: a first divided body; a second divided body that is assembled together with the first divided body to the drive unit or the movable body; and a ventilation hole formed in a portion covering the front surface of the drive unit, the first divided body and the second divided body each having a first and second element that constitutes the ventilation hole, and the ventilation hole being formed at a boundary between the first divided body and the second divided body by combining the first and second elements. Configuration 2: A cover for a drive unit of a movable body, the cover comprising: a first divided body; a second divided body that is assembled together with the first divided body to the drive unit or the movable body; and a ventilation hole formed in a portion covering the front surface of the drive unit, the front surface of the second divided body having a shape that protrudes further forward than the front surface of the first divided body, and the ventilation hole being formed in the front surface of the first divided body that is recessed further rearward than the front surface of the second divided body. Configuration 3: A cover for a drive unit of a movable body according to Configuration 1 or 2, wherein the first divided body has a stator housing portion that houses a stator of a motor that constitutes the drive unit, and a notch is formed in the stator housing portion as the first element that constitutes the air vent.Configuration 4: A cover for a drive unit of a movable body according to any one of Configurations 1 to 3, wherein the second divided body has a frame portion that is formed to outline the air vent and fits into the notch of the first divided body as the second element that constitutes the air vent.Configuration 5: A cover for a drive unit of a movable body according to Configuration 4, wherein the frame portion of the second divided body has a slope that is inclined toward the stator toward the inside of the air vent.Configuration 6: A cover for a drive unit of a movable body according to any one of Configurations 1 to 5, wherein a clearance between the peripheral edge of the air vent and the stator is 5 mm or less.Configuration 7: A cover for a drive unit of a moving body according to any one of configurations 1 to 6, wherein the first divided body has a first fixing portion fixed to the drive unit, and the second divided body has a second fixing portion fixed to a frame of the moving body, and the first divided body and the second divided body can be separately fixed to their respective fixing targets.Configuration 8: A cover for a drive unit of a moving body according to configuration 7, wherein the first divided body has a shaft hole through which an output shaft extending from a main body of the drive unit passes, and a peripheral portion of the shaft hole protrudes in the direction in which the output shaft extends beyond the portion where the first fixing portion is formed.Configuration 9: A cover for a drive unit of a moving body according to configuration 7 or 8, wherein the frame has support claws that support the first divided body, and the first divided body is positioned on the support claws and has engagement claws that hook onto the frame. Configuration 10: A drive unit cover for a movable body according to any one of configurations 7 to 9, wherein the second divided body has a through hole formed in a portion located rearward of the movable body relative to the vent hole, and the through hole is located at the lowest point of the second divided body when the second divided body is assembled to the movable body.Configuration 11: A drive unit cover for a movable body according to configuration 10, wherein the maximum width of the openings of the vent hole and the through hole is more than 10 mm and not more than 13 mm.Configuration 12: A drive unit cover for a movable body according to configuration 10, wherein the maximum width of the openings of the vent hole and the through hole is 10 mm or more.

[0072] 1 Vehicle, 2 Frame, 2a Head tube, 2b Front fork, 2c Down tube, 2d Seat tube, 2e Top tube, 2f Chain stay, 2g Seat stay, 3a Front wheel, 3b Rear wheel, 4 Handlebar, 5 Saddle, 6 Crank arm, 7 Pedal, 8 Battery, 9 Switch unit, 10 Motor bracket, 11 First opening, 12 Second opening, 13 Unit fixing portion, 14 Cover fixing portion, 15 Support claw, 20 Drive unit, 21 Unit body, 21a Convex portion, 22 Stator portion, 23 Board, 24 Output shaft, 25 First fixing portion, 26 Second fixing portion, 27a Alignment protrusion, 27b Recess, 28 Front sprocket, 29 Bolt, 30 Drive unit cover, 31 Ventilation hole, 40 Side cover, 41 First opening, 42 Second opening, 43 Notch, 44 Fixing portion, 45 Engagement claw, 46 Stator accommodating portion, 47a First region, 47b Second region, 47c Third region, 48 Bolt, 50 Under cover, 51 Fixing portion, 52 Through hole, 53 Frame portion, 54 Bolt, 60 Stator cover, 61a Alignment groove, 61b Convex portion

Claims

1. A cover for a drive unit of a moving body, comprising: a first divided body; a second divided body that is assembled to the drive unit or the moving body together with the first divided body; and an air vent formed in a portion covering the front of the drive unit, wherein the first divided body and the second divided body each have first and second elements that constitute the air vent, and the air vent is formed at the boundary between the first divided body and the second divided body by the combination of the first and second elements.

2. A cover for a drive unit of a moving body, comprising: a first divided body; a second divided body that is assembled to the drive unit or the moving body together with the first divided body; and an air vent formed in a portion that covers the front of the drive unit, wherein the front of the second divided body has a shape that protrudes more toward the front of the moving body than the front of the first divided body, and the air vent is formed in the front of the first divided body that is recessed further rearward of the moving body than the front of the second divided body.

3. A cover for a drive unit of a moving body as described in claim 1 or 2, wherein the first divided body has a stator accommodating section that accommodates the stator of the motor that constitutes the drive unit, and the stator accommodating section has a notch formed therein as the first element that constitutes the air vent.

4. A cover for a drive unit of a moving body as described in claim 3, wherein the second divided body is the second element constituting the ventilation hole, and has a frame portion formed to outline the ventilation hole and fitted into the notch of the first divided body.

5. A cover for a drive unit of a moving body according to claim 4, wherein the frame portion of the second divided body has a slope that is inclined so as to approach the stator toward the inside of the air vent.

6. A cover for a drive unit of a moving object according to claim 1 or 2, wherein the clearance between the peripheral edge of said ventilation hole and said stator is 5 mm or less.

7. A cover for a drive unit of a moving body as described in claim 1 or 2, wherein the first divided body has a first fixing portion fixed to the drive unit, the second divided body has a second fixing portion fixed to the frame of the moving body, and the first divided body and the second divided body can be fixed separately to their respective fixing objects.

8. A cover for a drive unit of a moving body as described in claim 7, wherein the first divided body has an axial hole through which an output shaft extending from the main body of the drive unit passes, and the peripheral portion of the axial hole protrudes in the direction in which the output shaft extends beyond the portion where the first fixing portion is formed.

9. A cover for a drive unit of a moving body as described in claim 7, wherein the frame is formed with support claws that support the first divided body, and the first divided body is positioned on the support claws and has an engaging claw that hooks onto the frame.

10. A cover for a drive unit of a movable body as described in claim 7, wherein the second divided body has a through hole formed in a portion located rearward of the movable body relative to the air vent, and the through hole is located at the lowest point of the second divided body when the second divided body is assembled to the movable body.

11. A cover for a drive unit of a moving object according to claim 10, wherein the maximum width of the openings of the ventilation holes and the through holes is more than 10 mm and not more than 13 mm.

12. A cover for a drive unit of a moving object according to claim 10, wherein the maximum width of the opening of the ventilation hole and the through hole is 10 mm or more.

Images