In-wheel motor

Abstract

Provided is an in-wheel motor capable of suppressing excessive torque from being transmitted to a rotor or a wheel and capable of shortening the length of a shaft. In an outer rotor type motor in which a rotor (9) is provided on the outer periphery of a stator (6), an in-wheel motor (1) provided inside a wheel is provided with a driving-side rotating member (10) that rotates integrally with the rotor (9), a driven-side rotating member (17) that rotates integrally with the wheel, and a transmission portion (18) that transmits torque between the driving-side rotating member (10) and the driven-side rotating member (17). The transmission portion (18) is configured to, in a case where torque acting on either of the driving-side rotating member (10) and the driven-side rotating member (17) is equal to or greater than a predetermined torque that is predetermined in advance, cause the driving-side rotating member (10) and the driven-side rotating member (17) to relatively rotate, thereby limiting torque transmitted between the driving-side rotating member (10) and the driven-side rotating member (17) to the predetermined torque.

Description

Technical Field

[0001] This invention relates to an in-wheel electric motor that is built into a wheel. Background Technology

[0002] Patent Documents 1 and 2 disclose an in-wheel motor that is a so-called internal rotor type motor. This internal rotor type motor has an annular stator connected to a housing held on a vehicle body, and a rotor arranged inside the stator at predetermined intervals. In these in-wheel motors, a wheel is connected to its output shaft via a transmission component such as a speed reducer. Furthermore, a torque limiter is provided to suppress damage to the motor or speed reducer in the event of an unexpectedly large load being input from the wheel.

[0003] Specifically, in the in-wheel motor described in Patent Document 1, a reduction gear pair is mounted on the output shaft of the motor, and a cylindrical shaft protruding in the axial direction is formed on the output gear of the reduction gear pair. At the end of the cylindrical shaft, slits are formed in the circumferential direction at predetermined intervals. Furthermore, the wheel hub on which the wheel is mounted is arranged on the same axis as the cylindrical shaft, and a protrusion that engages with the slit is formed on the portion of the wheel hub opposite the cylindrical shaft. The protrusion is formed with strength sufficient to break under unexpected loads applied to the wheel, thus functioning as a torque limiter.

[0004] Patent Document 2 describes an in-wheel motor with a hollow transmission shaft that transmits torque from the motor via a reduction gear pair. A wheel is connected to this transmission shaft via a planetary gear that functions as a speed reducer. The transmission shaft has a weakest portion, which is formed with a plate thickness (wall thickness) thinner than other portions, or made of a material less durable than other portions. Furthermore, this weakest portion is configured to function as a torque limiter. That is, the plate thickness and material of the weakest portion are determined in such a way that the weakest portion will break if an unexpected load is applied to the wheel.

[0005] Patent Document 3 describes an in-wheel motor comprising an external rotor type motor. This external rotor type motor has an annular stator connected to a housing held on a vehicle body, and a rotor arranged at predetermined intervals on the outside of the stator. Furthermore, the rotor and a rotating shaft mounted on a central axis of rotation are connected by a bushing, and a wheel is mounted on this rotating shaft. Additionally, an inverter for controlling the frequency or current value of the alternating current energizing the coils wound on the stator is disposed within the space on the inner periphery of the stator.

[0006] Prior art literature

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2016-130572

[0009] Patent Document 2: Japanese Patent Application Publication No. 2010-47121

[0010] Patent Document 3: Japanese Patent Application Publication No. 2020-14303 Summary of the Invention

[0011] The problem that the invention aims to solve

[0012] The in-wheel motor described in Patent Document 1 is configured to connect a rotating component on the motor side to a rotating component on the wheel side, and this connection functions as a torque limiter. Furthermore, the in-wheel motor described in Patent Document 2 has a weakest point that functions as a torque limiter on the transmission shaft that transmits torque from the motor to the wheel. That is, in the in-wheel motors described in Patent Documents 1 and 2, the motor, the input-side transmission component (or input-side transmission section) that transmits the motor's torque, the torque limiter (or the weakest point), and the output-side transmission component (or output-side transmission section) are arranged in the axial direction. Therefore, it is necessary to ensure the portion of the torque limiter is arranged in the axial direction, and correspondingly, there is a possibility that the shaft length of the in-wheel motor may increase. That is, there is a possibility that the mounting capacity of the in-wheel motor may decrease.

[0013] This invention was made in view of the above-mentioned technical problems, and its purpose is to provide an in-wheel motor that can suppress the transmission of excessive torque to the rotor or wheel and can shorten the shaft length.

[0014] Methods for solving problems

[0015] To achieve the above objective, this invention is an in-wheel motor, in which an external rotor type motor is disposed inside the wheel. The external rotor type motor is composed of a stator formed into a cylindrical shape and a cylindrical rotor disposed on the outer periphery of the stator at predetermined intervals. The in-wheel motor is characterized by comprising: a drive-side rotating member that rotates integrally with the rotor; a driven-side rotating member that rotates integrally with the wheel; and a transmission unit that transmits torque between the drive-side rotating member and the driven-side rotating member. The transmission unit is configured such that, when the torque acting on either the drive-side rotating member or the driven-side rotating member is greater than or equal to a predetermined torque, the drive-side rotating member and the driven-side rotating member rotate relative to each other, thereby limiting the torque transmitted between the drive-side rotating member and the driven-side rotating member to the predetermined torque.

[0016] Furthermore, in this invention, at least a portion of the transmission part may overlap with the stator in the direction of the rotational center axis of the wheel.

[0017] Alternatively, in this invention, the transmission part may be disposed on the inner periphery of the stator.

[0018] Furthermore, in this invention, the transmission unit may be configured to transmit torque by being integrated with either the driving-side rotating member or the driven-side rotating member, and by being in contact with the other of the driving-side rotating member and the driven-side rotating member in the rotational direction.

[0019] Furthermore, in this invention, the transmission unit may also be configured such that it will break if the torque transmitted between the electric motor and the wheel exceeds a predetermined upper limit torque.

[0020] Furthermore, in this invention, the driving-side rotating member can also be formed as an annular shape, the driven-side rotating member can be formed as an annular shape, and the outer peripheral side is formed in contact with the side of the driving-side rotating member, and the transmission part is configured to connect the contact part that contacts the side of the driving-side rotating member and the side of the driven-side rotating member.

[0021] Furthermore, in this invention, the driving-side rotating member can also be configured such that it is formed in an annular shape, the driven-side rotating member has a shaft portion fitted into the inner circumference of the driving-side rotating member, a key is formed on either the inner circumferential surface of the driving-side rotating member or the outer circumferential surface of the shaft portion, and a keyway engaging with the key is formed on the other of the inner circumferential surface of the driving-side rotating member or the outer circumferential surface of the shaft portion, and the transmission part includes the key.

[0022] Furthermore, in this invention, it can also be configured such that, when the driving-side rotating member and the driven-side rotating member are connected, the transmission part forms a predetermined gap between either the driving-side rotating member or the driven-side rotating member in the rotational direction of the rotor.

[0023] Furthermore, in this invention, it can also be configured such that, in the state where the driving-side rotating component and the driven-side rotating component are connected, the transmission part is in close contact with the driving-side rotating component and the driven-side rotating component in the rotational direction of the rotor.

[0024] Furthermore, in this invention, the transmission unit may also be configured to transmit torque through the frictional force generated by the contact between the driving-side rotating member and the driven-side rotating member.

[0025] Furthermore, in this invention, the transmission unit may be configured such that it will slip when the torque transmitted between the electric motor and the wheel is above a predetermined upper limit torque.

[0026] Furthermore, in this invention, the driving-side rotating member may be formed in an annular shape, the driven-side rotating member may have a shaft portion fitted into the inner circumference of the driving-side rotating member, and the transmission portion may include a contact portion in which the inner circumferential surface of the driving-side rotating member contacts the outer circumferential surface of the shaft portion.

[0027] Furthermore, in this invention, one of the driving-side rotating member and the driven-side rotating member may also be provided with two plates, the two plates being spaced apart by a predetermined interval in the axial direction of the rotor and being arranged opposite each other such that they are separated by the inner edge of the driving-side rotating member or the outer edge of the driven-side rotating member, and the transmission part includes a contact part in which the two plates contact the side surface of the driving-side rotating member or the driven-side rotating member.

[0028] Furthermore, it can also be configured to include an elastic component that presses at least one of the two plates toward the other plate.

[0029] Invention Effects

[0030] According to this invention, an in-wheel motor is constructed by using an external rotor type motor with a rotor provided on the outer periphery of the stator. The in-wheel motor is configured such that, when the torque acting on either a drive-side rotating member that rotates integrally with the rotor or a driven-side rotating member that rotates integrally with the wheel exceeds a predetermined torque, the rotating members of these components are rotated relative to each other, thereby limiting the transmitted torque to a predetermined torque. In other words, a torque limiter is provided on the output side of the rotor in the external rotor type motor. By constructing it in this way, the motor section that generates torque and the torque transmission section that transmits the torque to the wheel can be arranged radially, and the shaft length of the in-wheel motor can be shortened. Attached Figure Description

[0031] Figure 1 This is a cross-sectional view illustrating a first embodiment of an in-wheel motor in an embodiment of the invention.

[0032] Figure 2 for Figure 1 An enlarged view of part A in the image.

[0033] Figure 3 To indicate Figure 2 Arrow B in the view.

[0034] Figure 4 This is a perspective view illustrating the structure of a second embodiment that connects the rotor cover and the connecting component.

[0035] Figure 5 This is a cross-sectional view used to illustrate the structure of the connecting portion in the second embodiment.

[0036] Figure 6 This is a cross-sectional view illustrating the structure of a third embodiment that connects the rotor cover and the connecting component. Detailed Implementation

[0037] exist Figure 1 The image shows a cross-sectional view of an example of an in-wheel motor used to illustrate an embodiment of the invention. Figure 1 The in-wheel motor 1 shown has a retaining part 3 with a through hole 2, into which a shock absorber mechanism 4, such as a suspension or shock absorber, is inserted. That is, the in-wheel motor 1 is held in the vehicle body (not shown) by the shock absorber mechanism 4.

[0038] On the outer side of the retaining part 3 in the vehicle width direction (hereinafter referred to as the outer panel side), a steering knuckle 5 with a rectangular cross-sectional shape is connected. Therefore, the retaining part 3 and the steering knuckle 5 are integrated and configured to rotate around the shock absorber mechanism 4.

[0039] A cylindrical stator 6 is connected to the steering knuckle 5 in such a way that it surrounds the outer periphery of the steering knuckle 5. Figure 1 The stator 6 shown includes a cylindrical base portion 6a centered on the central axis J of the wheel, a cylindrical stator yoke 6b fitted onto the outer periphery of the base portion 6a, and an annular mounting portion 6c formed on the inner periphery of the base portion 6a. Additionally, in Figure 1 The base portion 6a shown has a hollow portion formed therein, and is configured such that the stator 6 is cooled by allowing refrigerant to flow in the hollow portion.

[0040] A stator yoke 6b is mounted on the outer peripheral surface of the base portion 6a by means of heat fitting or spline engagement. The stator yoke 6b is constructed by laminating a steel plate formed into a ring shape, and is assembled by fitting the stator yoke 6b into the base portion 6a. Specifically, the stator yoke 6b is mounted from one side of the base portion 6a in the axial direction (…). Figure 1 The stator yoke 6b is fitted onto the base portion 6a by means of the left side shown, thereby assembling the stator yoke 6b onto the base portion 6a. Therefore, in Figure 1 In the example shown, a flange portion 6d is formed on the outer plate side of the base portion 6a in order to achieve positioning of the stator yoke 6b. In addition, when the base portion 6a and the stator yoke 6b are splinedly engaged, a limiting member such as an elastic retaining ring may be provided on the inner plate side of the stator yoke 6b to limit the movement of the stator yoke 6b inward in the vehicle width direction (hereinafter referred to as the inner plate side).

[0041] On the outer circumferential surface of the stator yoke 6b, a plurality of stator teeth (not shown) are formed at predetermined intervals in the circumferential direction, and a coil 6e is wound on each stator tooth. Furthermore, the side of the mounting portion 6c facing the inner plate abuts against the opening end of the steering knuckle 5 and is fixed by bolts 7 in a clamping manner to the mounting portion 6c. Figure 1 In the example shown, the cylindrical shaft 8, integrally formed with the steering knuckle 5, contacts the end of the stator yoke 6b on the inner plate side. Furthermore, the coil 6e is air-cooled by the airflow generated within the rotor cover 10 due to the rotation of the rotor 9.

[0042] A cylindrical rotor 9 is arranged at intervals between itself and the outer peripheral surface of the stator 6 described above. That is, Figure 1 The in-wheel type motor 1 shown is an external rotor type motor in which a rotor 9 is provided on the outer periphery of the stator 6. The rotor 9 is formed in the same way as the stator yoke 6b by laminating multiple steel plates that are formed into a ring, and permanent magnets 9a are assembled on its inner periphery at predetermined intervals in the circumferential direction.

[0043] The rotor 9 is mounted on a rotor cover 10 (not shown) located inside a wheel by means of heat fitting or spline engagement. That is, the rotor 9 and rotor cover 10 are connected together in such a way that they rotate as a single unit. Specifically, Figure 1 The rotor cover 10 shown is composed of a cylindrical portion 10a on which the rotor 9 is connected to the inner surface, and an annular side portion 10b connected to the end of the outer plate side of the cylindrical portion 10a. The rotor 9 is connected to the inner surface of the cylindrical portion 10a in a manner that allows it to rotate integrally.

[0044] Figure 1 The inner diameter of the cylindrical portion 10a shown, up to the position where the rotor 9 is assembled, is formed to be larger than the inner diameter of the rotor cover 10 side. That is, a height difference is formed on the inner surface of the cylindrical portion 10a. Therefore, positioning is achieved when assembling the cylindrical portion 10a by means of this height difference. In addition, when the rotor 9 is splinedly engaged with the rotor cover 10, a limiting member such as an elastic retaining ring can be provided on the inner plate side of the rotor 9 to limit the movement of the rotor 9 towards the inner plate side.

[0045] Furthermore, the end of the inner plate side of the cylindrical portion 10a is formed to the same position as the end of the inner plate side of the cylindrical shaft 8, and a sealing member 11 for preventing foreign matter from mixing in from the outside is provided between the inner surface of the cylindrical portion 10a and the outer surface of the cylindrical shaft 8.

[0046] The outer peripheral portion of the side panel 10b is formed opposite to the ends of the coil 6e and the outer plate side of the base portion 6a by a predetermined gap, and bends towards the inner plate side at the portion closer to the base portion 6a. A sealing member 11 for preventing foreign matter from entering is provided between this bent cylindrical portion and the base portion 6a. Furthermore, the inner plate side end of the bent cylindrical portion is formed by bending inward. That is, at least a portion of the inner edge of the side panel 10b overlaps with the stator 6 on the inner side of the stator 6 or in the direction of the rotation center axis of the wheel. Furthermore, the plate thickness of the inner edge of the side panel 10b is formed to be thicker than the plate thickness of other portions. In addition, a recess 10c with a circular cross-sectional shape is formed on the outer plate side of the inner edge of the side panel 10b.

[0047] Furthermore, a cylindrical portion 5a protruding towards the outer plate side is integrally formed in the inner circumferential portion of the steering knuckle 5. In this hollow portion, a support shaft 12 is held in a manner that allows relative rotation with the cylindrical portion 5a. This support shaft 12 is a component for mounting the wheel and is composed of the cylindrical portion 12a inserted into the cylindrical portion 5a and a flange portion 12b formed at the end of the cylindrical portion 12a on the outer plate side. An external thread portion 13a is integrally formed on the flange portion 12b, and a nut (not shown) for fixing the wheel is threaded tightly onto the external thread portion 13a.

[0048] Between the aforementioned cylindrical portions 5a and 12a, a roller 14 is arranged to withstand the radial and axial loads generated between the cylindrical portions 5a and 12a. That is, an angular contact ball bearing functions as an outer race in the cylindrical portion 5a and as an inner race in the cylindrical portion 12a. Furthermore, sealing members 15 are provided on both sides of the roller 14, and a rotating shaft 16 is fitted into the hollow portion of the support shaft 12. A clamping mechanism is formed on the inner plate side of this rotating shaft 16. Figure 1 The flange 16a is formed in the manner of a roller 14 on the inner plate side, and an external thread 16b is formed on the outer plate side, so that the nut 16c, which abuts against the end of the support shaft 12 on its outer peripheral side, is fastened to the external thread 16b. That is, by fastening the nut 16c to the rotating shaft 16, the support shaft 12 is positioned, and as a result, the stator 6 and the rotor 9 are positioned in the axial direction.

[0049] A ring-shaped, plate-like connecting member 17 is provided for connecting the rotor 9 (more specifically, the rotor cover 10) and the support shaft 12 (more specifically, the flange portion 12b). The flange portion 12b abuts against the inner plate side of the connecting member 17, and the flange portion 12b and the connecting member 17 are integrated by means of a rivet 13 having the external thread portion 13a. That is, the connecting member 17 is provided in a manner that allows it to rotate integrally with the wheel.

[0050] In addition, such as Figure 2 As shown, the cross-sectional shape of the outer peripheral end of the connecting member 17 is formed into an L-shape. Specifically, it includes a fitting portion 17a and a side wall portion 17b, wherein the fitting portion 17a is opposite to the inner edge of the rotor cover 10 in the radial direction and fits the rotor cover 10, and the side wall portion 17b is on the inner peripheral side of the rotor cover 10 and abuts against the side of the inner plate.

[0051] In this side wall portion 17b, a through hole 17c is formed at a position corresponding to the recess 10c formed on the side wall portion 10b of the rotor cover 10. The through hole 17c is as follows: Figure 3 As shown, it has a predetermined length in the circumferential direction. Furthermore, a positioning pin 18 is provided, which passes through a through hole 17c formed in the side wall portion 17b and is pressed into a recess 10c formed in the side side portion 10b of the rotor cover 10. That is, the portion connecting the rotor cover 10 and the connecting member 17 by the positioning pin 18 overlaps with at least a portion of the stator 6 on the inner side of the stator 6 or in the direction of the rotational center axis of the wheel.

[0052] Alternatively, multiple recesses 10c, through holes 17c, and locating pins 18 can be provided at predetermined intervals along the circumferential direction of the rotor cover 10 or the connecting member 17. Furthermore, the side portion 10b of the rotor cover 10 and the connecting member 17 can be integrated in the axial direction by riveting the top end of the inner plate side of the locating pin 18. Moreover, the recesses 10c can be formed in an arc shape, the through holes 17c can be formed in a circle, and the locating pins 18 can be pressed into the through holes 17c to connect the rotor cover 10 and the connecting member 17.

[0053] The in-wheel motor 1 configured as described above is subjected to a load in the direction that rotates the rotor 9 by utilizing the magnetic flux generated by energizing the coil 6e and the magnetic flux of the permanent magnet disposed in the rotor 9, and generates a torque corresponding to the load and the radius of the rotor 9. This torque is transmitted to the locating pin 18 integrated with the rotor cover 10, and the outer peripheral surface of the locating pin 18 and the inner peripheral surface of the through hole 17c formed on the connecting member 17 contact each other in the rotational direction of the rotor 9, thereby being transmitted to the connecting member 17. That is, the torque is transmitted from the rotor 9 to the wheel via the rotor cover 10, the locating pin 18, and the connecting member 17. Therefore, the rotor cover 10 corresponds to the "drive-side rotating member" in the embodiment of the invention, the connecting member 17 corresponds to the "driven-side rotating member" in the embodiment of the invention, and the locating pin 18 corresponds to the "transmission part" in the embodiment of the invention.

[0054] Furthermore, when the in-wheel motor 1 is outputting drive torque, for example, if excessive torque is input to the wheel due to a sudden change in wheel speed, a load corresponding to this excessive torque will act on the locating pin 18. Similarly, if a controller (not shown) used to control the current value energizing coil 6e malfunctions, resulting in unintended excessive torque, a load corresponding to this excessive torque will also act on the locating pin 18.

[0055] The strength of the locating pin 18 is determined to suppress the transmission of such excessive torque; in other words, it functions as a torque limiter. Specifically, the strength of the locating pin 18 is determined in such a way that a predetermined torque (upper limit torque) can be transmitted between the rotor 9 and the wheel, and the locating pin 18 will break if torque exceeding this upper limit torque is transmitted to the rotor housing 10 or the connecting component 17. The strength of the locating pin 18 can be adjusted by appropriately setting the material or outer diameter of the locating pin 18, etc.

[0056] Therefore, by connecting the rotor 9 and the wheel using the rotor cover 10 and the connecting member 17, and by determining the strength of the connecting part (here, the locating pin 18) to function as a torque limiter that will break if a predetermined torque is transmitted, it is possible to suppress (limit) the transmission of excessive torque between the rotor 9 and the wheel. That is, the torque transmitted between the rotor cover 10 and the connecting member 17 can be limited to a predetermined torque.

[0057] Furthermore, as described above, by employing an external rotor type motor and providing a connecting part (here, the locating pin 18) that functions as a torque limiter at the output side of the rotor 9, the motor section that generates torque and the torque transmission section that transmits the torque to the wheel can be arranged radially. Therefore, compared to the case of using an internal rotor type motor, the shaft length of the wheel-mounted motor 1 can be shortened. In particular, by connecting the rotor cover 10 and the connecting member 17, and forming a part that functions as a torque limiter (here, the part where the locating pin 18 is provided) inside the stator 6, it is not necessary to ensure space for installing the torque limiter in the axial direction, thereby shortening the shaft length of the wheel-mounted motor 1.

[0058] Furthermore, as described above, by forming a through hole 17c of predetermined length in the circumferential direction on the connecting member 17, when the connecting member 17 is assembled onto the rotor cover 10, a phase (position in the rotational direction) offset between the rotor cover 10 and the connecting member 17 can be allowed, thereby improving assemblability. In other words, the error between the position of the recess 10c formed on the rotor cover 10 and the position of the through hole 17c formed on the connecting member 17 can be increased. That is, machining errors during the manufacturing of the rotor cover 10 and the connecting member 17 can be tolerated, thereby reducing manufacturing costs.

[0059] exist Figure 4 The diagram shows a perspective view of another embodiment (second embodiment) of the in-wheel motor used to illustrate an embodiment of the invention, and in Figure 5 A cross-sectional view of this embodiment is shown in the figure.

[0060] Figure 4 as well as Figure 5 The example shown is similar to the above in its mounting structure of rotor cover 10 and connecting component 17. Figures 1 to 3 The example shown is different. Specifically, a key 19 is formed on the outer peripheral surface of the fitting portion 17a along the axial direction of the connecting member 17. Furthermore, a keyway 20, which is wider than the key 19, is formed on the inner surface of the rotor cover 10. That is, in the above-described... Figures 1 to 3In the example shown, the rotor cover 10 and the connecting member 17 are connected in a manner capable of transmitting torque by means of the locating pin 18, in contrast, in Figure 4 as well as Figure 5 In the example shown, the rotor cover 10 and the connecting member 17 are connected in a manner capable of transmitting torque by key 19 and keyway 20. In addition, the aforementioned fitting portion 17a corresponds to the "shaft portion" in the embodiment of this invention.

[0061] Furthermore, the strength of key 19 is determined in a manner that allows it to function as a torque limiter. Specifically, the strength of key 19 is determined in the same way as the strength of locating pin 18 described above; that is, the torque that can be transmitted between rotor 9 and wheel is predetermined, and key 19 will break if a torque exceeding this value is transmitted. The strength of key 19 can be adjusted by appropriately setting the material or outer diameter of key 19. In other words, key 19 corresponds to the "transmission part" in the embodiment of this invention.

[0062] Therefore, as Figures 1 to 3 Similarly, in the example shown, the rotor 9 is connected to the wheel by means of the rotor cover 10 and the connecting member 17, and the strength of the connecting part (key 19 in this case) is determined to be such that it functions as a torque limiter that will break if a torque exceeding a predetermined torque is transmitted, thereby suppressing the transmission of excessive torque between the rotor 9 and the wheel.

[0063] Furthermore, as described above, by connecting the rotor cover 10 and the connecting member 17, and forming a part that functions as a torque limiter (here, the part with the key 19) inside the stator 6, it is not necessary to ensure space for setting the torque limiter in the axial direction, and the situation of increasing the size of the in-wheel motor 1 can be suppressed.

[0064] Furthermore, as described above, by making the width of the keyway 20 formed on the connecting member 17 wider than the width of the key 19 formed on the rotor cover 10, when the connecting member 17 is assembled onto the rotor cover 10, a phase (position in the rotational direction) offset between the rotor cover 10 and the connecting member 17 can be allowed, thereby improving assemblability. In other words, the error between the position of the key 19 formed on the rotor cover 10 and the position of the keyway 20 formed on the connecting member 17 can be increased. That is, machining errors during the manufacturing of the rotor cover 10 and the connecting member 17 can be tolerated, thereby reducing manufacturing costs.

[0065] In the above Figures 1 to 3 The structure shown, and Figure 4 as well as Figure 5 The structure shown improves the assemblability of the rotor cover 10 and the connecting component 17. However, in cases where the direction of the torque generated by the rotor 9 is reversed to suppress variations in driving force when traveling on uneven surfaces, the torque cannot be quickly transmitted to the wheels after the direction of the torque is reversed. Specifically, in Figures 1 to 3 In the example shown, during the period from when the locating pin 18 contacts one end of the through hole 17c until the locating pin 18 contacts the other end, torque is not transmitted to the wheel. Similarly, in Figure 4 as well as Figure 5 In the example shown, torque is not transmitted to the wheel during the period from when key 19 contacts one side of keyway 20 until key 19 contacts the other side.

[0066] Therefore, by forming the through hole 17c into a circle to press in the positioning pin 18, the positioning pin 18 can be made to fit tightly against the through hole 17c. Similarly, by forming the width of the keyway 20 to be approximately the same as the width of the key 19 and pressing the key 19 into the keyway 20, the key 19 can also fit tightly against the keyway 20.

[0067] Furthermore, in the aforementioned structures, the locating pin 18 and key 19 are configured to transmit torque by pressing the through hole 17c and keyway 20, and to function as torque limiters by breaking the locating pin 18 and key 19. Therefore, if a large torque is input causing the locating pin 18 and key 19 to break, it will become impossible to transmit torque between the rotor 9 and the wheel.

[0068] Therefore, in another embodiment of the invention (the third embodiment), it is configured such that, even after a large torque is input to the rotor 9 or the wheel, the torque can be transmitted in the same manner as before the torque transmission was interrupted. Figure 6 The image shows an enlarged cross-sectional view used to illustrate the structure.

[0069] Figure 6 The in-wheel motor 1 shown is configured such that the rotor cover 10 and the connecting member 17 transmit torque through friction. Specifically, spline teeth 17d are formed on the outer peripheral surface of the fitting part 17a, and two annular plate members 21a and 21b that engage with the spline of the fitting part 17a are arranged in a mutually opposing manner.

[0070] Furthermore, annular friction members 22 are installed on two surfaces of the inner circumference of the rotor cover 10, and two plate members 21a and 21b clamp the rotor cover 10 in contact with the friction members 22. To generate the clamping force on the rotor cover 10, a disc spring 23 is provided between the side wall portion 17b and one plate member 21a. This disc spring 23 is a component for defining the upper limit torque transmitted between the rotor cover 10 and the connecting member 17, and its spring constant and displacement are set such that they exert a frictional force corresponding to the predetermined upper limit torque.

[0071] Furthermore, an elastic retaining ring 24 is provided to generate a reaction force to overcome the pressing force produced by the disc spring 23. This elastic retaining ring 24 is positioned relative to the inner plate side of the other plate component 21b. Figure 6 The movement of the disc spring (on the left side) is restricted. Furthermore, the disc spring 23 described above corresponds to the "elastic member" in the embodiment of this invention.

[0072] As described above, by using two plate components 21a and 21b to clamp the rotor cover 10, it is possible to assemble it without aligning the rotor cover 10 with the connecting component 17 in phase (position in the rotation direction), thereby improving assemblability.

[0073] Furthermore, when a large torque is applied to the rotor housing 10 and the connecting member 17, by rotating (sliding) the rotor housing 10 and the connecting member 17 relative to each other, excessive torque can be suppressed from being transmitted to the rotor 9 or the wheel. That is, the contact portion between the rotor housing 10 (specifically the friction member 22) and the connecting member 17 functions as a torque limiter. Thus, even when the rotor housing 10 and the connecting member 17 rotate relative to each other, the torque acting on them is reduced, so that when the rotor housing 10 and the connecting member 17 rotate as a unit, the same torque as before the relative rotation can be transmitted thereafter. Therefore, even after functioning as a torque limiter, it is not necessary to replace the in-wheel motor 1, etc.

[0074] In addition, Figure 6 In the example shown, although the two plate components 21a and 21b are connected to the connecting member 17, the two plate components 21a and 21b can also be arranged such that they rotate integrally with the rotor cover 10 and clamp the outer periphery of the connecting member 17. Furthermore, the structure in which the rotor cover 10 and the connecting member 17 are connected in a manner capable of transmitting torque through friction is not limited to... Figure 6 The structure shown can also be configured, for example, to press the fitting portion 17a into place. Figure 1The torque is transmitted through the friction between the inner circumferential surface of the rotor cover 10 and the outer circumferential surface of the connecting member 17.

[0075] Symbol Explanation

[0076] One wheel with an internal electric motor;

[0077] 5a, 12a cylindrical sections;

[0078] 6. Stator;

[0079] 6a Base section;

[0080] 6b Stator yoke;

[0081] 6c Installation Section;

[0082] 6d flange portion;

[0083] 6e coil;

[0084] 9. Rotor;

[0085] 9a Permanent magnet;

[0086] 10. Rotor cover;

[0087] 10a Cylindrical section;

[0088] 10b Side view;

[0089] 10c concavity;

[0090] 17 Connecting components;

[0091] 17a Fitting part;

[0092] 17b Side wall portion;

[0093] 17c Through hole;

[0094] 17d spline teeth;

[0095] 18 locating pins;

[0096] 19 keys;

[0097] 20 keyways;

[0098] Components 21a and 21b;

[0099] 22 Friction components;

[0100] 23. Disc spring;

[0101] 24. Elastic retaining ring.

Claims

1. An in-wheel motor comprising an external rotor type motor disposed inside the wheel, the external rotor type motor comprising a stator formed into a cylindrical shape and a cylindrical rotor disposed on the outer periphery of the stator at predetermined intervals. The in-wheel motor is characterized by having: A drive-side rotating component that rotates integrally with the rotor; Driven-side rotating component, which rotates integrally with the wheel; The transmission unit transmits torque between the driving-side rotating component and the driven-side rotating component. The transmission unit is configured such that, when the torque acting on either the driving-side rotating member or the driven-side rotating member is greater than or equal to a predetermined torque, the driving-side rotating member and the driven-side rotating member rotate relative to each other, thereby limiting the torque transmitted between the driving-side rotating member and the driven-side rotating member to the predetermined torque. The drive-side rotating component comprises a cylindrical portion and a side portion connected to the rotor on the inner surface. The side portion extends radially inward from the end of the cylindrical portion on the outer side of the vehicle in the vehicle width direction, and bends towards the inner side of the stator on the inner side of the stator in the vehicle width direction, and further extends radially inward from this bent portion. The driven-side rotating component is annular and plate-shaped, and has an inner peripheral portion integrated with the wheel, and an outer peripheral portion that fits into the inner peripheral end of the innermost peripheral side of the side portion. The transmission section is configured to have a key integrally formed on the outer periphery in a radially outward state, and a keyway formed on the inner periphery end in a manner corresponding to the key, and the torque is limited by the key breaking.

2. The in-wheel motor as described in claim 1, characterized in that, The width of the key in the rotational direction of the driven side rotating component is smaller than the width of the keyway in the rotational direction of the driven side rotating component.

3. The in-wheel motor as described in claim 1 or 2, characterized in that, A sealing member for sealing with the stator is fitted onto the outer periphery of the portion of the side portion that extends radially inward from the end of the cylindrical portion in the vehicle width direction and bends inward from the inner periphery of the stator towards the vehicle width direction.

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