Mounting structure for a motor system housed in a wheel

Abstract

A mounting structure for a wheel-mounted motor system (100) is disclosed. The mounting structure includes the wheel-mounted motor system installed in a wheel (110) of the vehicle, and a torsion bar axle (TBA) assembly (200) for mounting the wheel-mounted motor system to a vehicle body. A rear portion of a motor housing (180) includes a stepped portion (185) formed in a stepped manner to have a reduced diameter and an annular mounting surface (186) arranged vertically from the stepped portion. The TBA assembly includes a drag arm (210) provided with a through hole (215) for surrounding the stepped portion of the motor housing, a bracket (220) integrated with the drag arm for mounting the drag arm to a vehicle body, and a plurality of mounting bolts (240) for mounting the motor housing to the drag arm.wherein, when the step portion is fitted into and coupled with the through hole, the mounting surface is in close contact with the towing arm.,

Description

Background1. Field of InterestEmbodiments of the present invention relate to a mounting structure for a motor system accommodated in a wheel, which enables the motor system accommodated in the wheel to be stably installed in a wheel of a vehicle, and which can increase the efficiency of mounting and removing the motor system accommodated in the wheel.2. Description of the Prior ArtIn general, an engine accommodated in a wheel, which is a technology applied to an electric engine using electricity as its power source, allows power to be transmitted directly from the engine disposed inside a rim of a wheel to the wheel, unlike transmission of power to the wheel through an engine, a transmission, and a drive shaft for rotating the wheel in a gasoline or diesel fuel-driven vehicle.Such an engine accommodated in a wheel can eliminate the need for driving and power transmission devices such as an engine, a transmission, and a differential gear, thereby reducing the weight of the vehicle, providing independent control of the wheel, improving the running performance, and reducing the power transmission energy loss.FIG. 1 is a perspective view schematically illustrating the arrangement of a conventional in-wheel engine system in a wheel, and FIG. 2 is a cross-sectional view illustrating the arrangement of the in-wheel engine system of FIG. 1.Referring to FIG. 1, when the motor system accommodated in the wheel is attached to the wheel 10, it is moved from the inside of the vehicle toward the outside of the vehicle. The in-wheel motor system includes an axle 20 installed at the center of the wheel 10 to rotate together with the wheel 10, a reducer 30 for reducing the rotational force of the in-wheel motor 40 and transmitting the reduced force to the axle 20, a motor 40 connected to the reducer 30 and accommodated in the wheel, and a disc brake 60 for generating a braking force by applying pressure to a disc 50 disposed between the wheel 10 and the axle 20.In such an in-wheel motor system, the reducer 30 needs to be provided to increase the torque of the in-wheel motor 40, and a brake system for performing braking, i.e., the disk 50 and the disk brake 60, needs to be installed in the wheel 10, and therefore, the attachment of the in-wheel motor system to the wheel 10 may result in inefficient utilization of the space and poor drivability of the vehicle due to the increase of unsprung mass.Further, when the motor system accommodated in the wheel is fixed to the wheel 10, the disc 50, the disc brake 60, and the reducer 30 are accommodated in the wheel, but due to the limited space in the wheel 30, the motor 40 accommodated in the wheel may protrude from the wheel 10, that is, toward the inside of the vehicle, and thus may be damaged by an impact from an external object.Further, the attachment of the wheel-housed motor system to the vehicle by a bracket (not shown) that usually has two bolt attachment holes can prevent stable installation of the wheel-housed motor system to the vehicle by a motor housing 41 of the wheel-housed motor 40, resulting in uncertain effectiveness of the support of the wheel-housed motor system when vibrations and shocks are transmitted from the road surface to the system.Korean Patent KR 10 0 875 004 B1 discloses a structure for fixing an engine system accommodated in a wheel to a vehicle. According to the disclosure of this document, the mounting structure for the motor accommodated in the wheel is provided with a bolt mounting hole in a bracket of a stator of the motor accommodated in the wheel to allow a bolt to pass through the hole, and the joint (bracket) to be installed on the vehicle is provided with two through holes penetrated by bolts such that the bolts are mounted in the bolt mounting holes in the bracket of the stator through the through holes in the joint. That is, as described above, the effectiveness of strength for assisting the attachment of the engine accommodated in the wheel to the vehicle may be uncertain when vibrations and shocks are transmitted from the road surface, and therefore there may be a risk of damage to the system by external shocks.Patent document JP 2005-329 817 A discloses a mounting structure for a wheel drive with a motor system comprising two motors arranged concentrically and in a step shape, wherein the motor system is mounted frontally on a wheel carrier.Patent document US 5 382 854 A discloses an engine system accommodated in a wheel, wherein a conventional strut suspension for attachment to a chassis is shown.Cited documentsPatent DocumentsKR 10 0 875 004 B1 (ILJIN GLOBAL CO., LTD.), 12 December 2008, page 4, paragraphs 12 to 15, FIG. 3 and FIG. 4.JP 2005-329 817 AU.S. Pat. No. 5,382,854 ASummaryAn object of the present invention is to provide an alternative mounting structure for a wheel-mounted motor system which can provide a miniaturized, compact wheel-mounted motor system for obtaining the best in-wheel space utilization, preventing damage to a wheel-mounted motor, and securing a stable connection of the wheel-mounted motor system by improving strength for assisting the mounting of the wheel-mounted motor to a vehicle.It is another aspect of the present invention to provide a mounting structure for an engine system accommodated in a wheel, which can improve the efficiency of installing and removing the engine system accommodated in the wheel by allowing the engine accommodated in the wheel to be easily installed in and removed from the vehicle without interference with other components.Additional aspects of the invention are set forth in part in the description which follows and in part will be obvious from the description, or may be learned by practice of the invention.To achieve the above objects, there is provided a mounting structure for an engine system housed in a wheel according to claim 1.According to an aspect of the present invention, a mounting structure for a wheel-mounted motor system for installing the wheel-mounted motor system in a vehicle includes the wheel-mounted motor system installed in a wheel of the vehicle for generating a rotational force for driving the wheel, and a torsion bar axle (TBA) assembly for mounting the wheel-mounted motor system to a vehicle body, wherein a rear part of a motor housing forming an outer appearance of the wheel-mounted motor system includes a step portion formed in a stepped manner to have a reduced diameter and an annular mounting surface vertically disposed from the step portion, and the TBA assembly includes a drag arm having a through hole, which is penetrated to surround the step portion of the motor housing, includes a bracket integrated with the trailing arm for fixing the trailing arm to a vehicle body, and a plurality of fixing bolts for fixing the motor housing to the trailing arm, wherein when the step portion is fitted into and coupled to the through hole, the fixing surface is in close contact with the trailing arm.A plurality of fastening holes may be formed at a constant interval along an outer circumferential surface of the fastening surface of the motor housing, and a plurality of coupling holes may be formed at positions corresponding to the fastening holes in a radial direction of the through hole of the trailing arm such that the fastening bolts are screw-connected to the fastening holes through the coupling holes.The motor system accommodated in the wheel may include: an in-wheel motor provided with a rotor and a stator disposed in a space formed in the wheel to generate a rotational force for driving the wheel, the rotor and the stator being disposed to face each other to define an accommodation space therebetween; a cycloid reducer installed in the accommodation space of the in-wheel motor and provided with an output shaft for transmitting a reduced amount of rotation to an axle installed on the wheel; and an input shaft for penetrating the motor accommodated in the wheel to rotate together with the rotor; a disc installed at an end of the input shaft protruding through the in-wheel motor, a disc brake for applying a braking force to the disc, and the motor housing provided with a front housing surrounding a front part of the motor accommodated in the wheel and having an open center, and a rear housing surrounding a rear part of the motor accommodated in the wheel and coupled to the front housing.The cycloid reducer may include: the input shaft fixed by the rotor to rotate together with the rotor; a pair of eccentric bearings connected to the input shaft to eccentrically transmit rotation of the input shaft; a pair of cycloid disks installed on the eccentric bearings, respectively, each of the eccentric bearings being positioned at a center of a corresponding one of the cycloid disks; and provided with a plurality of through holes formed radially around the center of each of the cycloid disks to eccentrically rotate the cycloid disks; a ring gear housing installed to surround the cycloid disks and provided with a plurality of rollers installed at a constant interval along an inner circumferential surface of the ring gear housing to contact outer circumferential surfaces of the cycloid disks, to enable the cycloid disks to perform a revolution rotation and a rotation about the center of the cycloid disks, and the output shaft coupled to the axis to rotate together with the axis, and provided with a plurality of output pins inserted into the respective through holes to compensate for the eccentricity of the center of the cycloid disks.An output housing and an input housing having hollow portions for allowing the output shaft and the input shaft to pass therethrough, respectively, may be further provided at a front portion of the output shaft and a rear portion of the ring gear housing, respectively, wherein the output housing, the input housing, and the ring gear housing are coupled by a plurality of coupling bolts, and the coupling bolts are fixed to the motor housing to prevent rotation of the ring gear housing.The output shaft may be provided with a shaft having a predetermined length and coupled to the axle and a flange extending from an end of the shaft in a radial direction of the shaft, wherein the output pins may be installed at the rear of the flange.Brief Description of the DrawingsThese and / or other aspects of the invention will become apparent and more readily understood from the following description of the embodiments given in conjunction with the accompanying drawings, of which: FIG. 1 is an exploded perspective view schematically illustrating a conventional motor system housed in a wheel; FIG. 2 is a cross-sectional view illustrating the arrangement of the in-wheel motor system of FIG. 1 ; FIG. 3 is an exploded perspective view illustrating a wheel-housed motor system of a mounting structure for a wheel-housed motor system according to an embodiment of the present invention; FIG. 4 is a cross-sectional view illustrating the arrangement of FIG. 3 ; FIG. 5 is an exploded perspective view illustrating a cycloid reducer provided in the in-wheel motor system according to the embodiment of the present invention; FIG. 6 is an exploded perspective view illustrating a mounting structure for the in-wheel motor system according to the embodiment of the present invention; and FIG. 7 is a cross-sectional view illustrating the arrangement of FIG. 6.Detailed DescriptionReference will now be made in detail to the embodiments of the present invention illustrated in the accompanying drawings. It should be noted that the terms used in the specification and appended claims should not be construed as being limited to general and dictionary meanings, but should be construed based on the meanings and concepts according to the spirit of the present invention on the basis of the principle that the inventor is allowed to define appropriate terms for best explanation. The preferred embodiments described in the specification and shown in the drawings are illustrative only and are not intended to represent all aspects of the invention, such that various equivalents and modifications may be made without departing from the spirit of the invention.Embodiments of the present invention are directed to a mounting structure for a wheel-mounted motor system that enables the wheel-mounted motor system to be stably mounted on a vehicle by a torsion bar axle (TBA) assembly (hereinafter referred to as a TBA assembly). The structure of the engine system housed in the wheel will be described below.FIG. 3 is an exploded perspective view illustrating a motor system accommodated in a wheel according to an embodiment of the present invention. FIG. 4 is a cross-sectional view illustrating the arrangement of FIG. 3, and FIG. 5 is an exploded perspective view illustrating a cycloid reducer provided in the motor system housed in the wheel.Referring to FIGS. 3 to 5, the wheel-housed motor system 100 according to the illustrated embodiment includes an axle 120 that rotates together with the wheel 110, a motor 130 housed in the wheel for generating a rotational force for driving the wheel 110, a cycloid reducer 140 for decreasing the rotational force and transmitting the decreased force to the axle 120, a disc 160 rotated by the motor 130 housed in the wheel, a disc brake 170 for applying pressure to the disc 160 to generate a braking force, and a motor housing 180 for forming an external appearance of the wheel-housed motor system 100.The axle 120 is coupled to the wheel 110 to rotate together with the wheel 110. A plurality of axle bolts 122 are radially installed on the axle 120 spaced from the center of the axle 120. The axle bolts 122 penetrate the wheel 110 and are fixed to the wheel 110 by the wheel nuts 112.The in-wheel motor 130, which is an electric motor provided with a rotor 134 and a stator 135, is installed in the wheel 110 to generate power for driving the wheel 110. The wheel-housed motor 130 is installed in the motor housing 180 having a front housing 181 and a rear housing 182 connected to each other by bolts 183, and a housing space 131 is provided in the center of the motor housing 180. The in-wheel motor 130 is provided with the rotor 134 and the stator 135 disposed in an inner space defined by the arrangement of the front housing 181 and the rear housing 182 so as to face each other. Magnets 134' are installed along the outer circumferential surface of the rotor 134 so as to be spaced apart from each other by a predetermined distance, and the stator 135 formed so as to surround the rotor 134 at a distance therefrom is wound by a coil (not shown). When electric power is supplied to the coil, an attractive force and a repulsive force are generated between the magnets 134' and the coil to rotate the rotor 134.The front housing 181 is provided with an open portion 181a having an opening at the center thereof. When the cycloid reducer 140 described later is installed in the accommodation space 131, a part of the cycloid reducer 140 is exposed through the open region 181 a.The rear portion of the rear housing 182 is provided with a step portion 185 formed in a stepped manner to have a reduced diameter and an annular mounting surface 186 vertically disposed from the step portion 185. A plurality of mounting holes 188 are formed at a mutual interval along the outer circumferential surface of the mounting surface 186. The fixing holes 188 are installed to penetrate the rear housing 182 and a part of the front housing 181, and are threaded on the inner circumferential surface thereof. Each of the mounting holes 188 may be formed to have a length that is about two-thirds the width of the motor housing 180, thereby improving the mounting of the motor housing 180 to the TBA assembly (see FIG. 6, "200") when the motor housing 180 is threadably coupled to the TBA assembly by mounting bolts (see FIG. 6, "240").The mounting surface 186, the step portion 185, and the mounting holes 188 provided to install the in-wheel motor system 100 to the TBA assembly 200 will be described below.The rear wall of the rear housing 182, i.e., the step portion 185, is provided with a three-phase supply terminal 136 for supplying electric power to the coil and an installation portion 189 in which the disc brake 170 is installed. The installation portion 189 protrudes from the rear wall of the step portion 185, and an input shaft 141 is installed in the installation portion 189 through the center of the installation portion 189. That is, as shown in FIGS. 3 to 5, the disc 160 is installed at the end of the input shaft 141, and the disc brake 170 is installed in the installation region 189 so as to apply a pressure to the disc 160. A bearing 137 is installed between the input shaft 141 and the installation portion 189, and the pulley 160 installed at one end of the input shaft 141 is fastened by a pair of pulley fastening nuts 161 installed on the front side and the rear side of the pulley 160 so that the pulley 160 rotates together with the input shaft 141. Here, the three-phase supply terminal 136, the installation portion 189 formed on the step portion 185, and the disk 160 are installed so as not to come out of the step portion 185 in the radial direction thereof. This prevents the components formed on the step portion 185 from not interfering with insertion of the step portion 185 into a through hole (see FIG. 6, "215") of a trailing arm (see FIG. 6, "210") of the TBA assembly 200 described later.The disc 160 and the disc brake 170 are brake devices generally used to decelerate a vehicle to a standstill, and therefore, they are sufficiently understood by those skilled in the art so that a detailed description thereof will be omitted.The cycloid reducer 140 according to the illustrated embodiment includes the input shaft 141 coupled to the rotor 134, a pair of eccentric bearings 142 connected to the input shaft 141 to eccentrically transmit the rotation of the input shaft 141, a pair of cycloid disks 143 eccentrically rotated by the eccentric bearings 142, a ring gear housing 144 having rollers 145 installed thereon to allow the cycloid disks 143 to be fixed and rotate about its own axis, and an output shaft 151 provided with output pins 153 inserted into a plurality of through holes 143' formed in the cycloid disks 143, respectively.The cycloid reducer 140, which functions to boost the torque of the motor 130 housed in the wheel, is located in the housing space 131 of the motor 130 housed in the wheel.The input shaft 141 has a predetermined length and is installed through the rotor 134. As shown in FIGS. 3 to 5, the input shaft 141 has a portion near the center thereof fitted into the rotor 134, and is fastened to rotate together with the rotor 134 by the input shaft fastening nuts 139 installed to form close contact with the front and rear sides of the rotor. An end portion of the input shaft 141 penetrates the rear housing 182 of the motor housing 180, and the disc 160 is installed at the one end of the input shaft 141 as described above. The other end portion of the input shaft 141 is coupled to the pair of eccentric bearings 142. The other end of the input shaft 141 is provided with a spline 141a projecting from the outer circumferential surface of the input shaft 141, and each of the eccentric bearings 142 is provided with a spline 142' matched with the spline 141a in shape.A connecting ring 141 bis installed at the outer end of the input shaft 141 to prevent displacement of the eccentric bearings 142.The pair of eccentric bearings 142 is provided with an eccentric hole formed to be offset from the center of the eccentric bearings 142 to allow the input shaft 141 to be inserted into the holes and to eccentrically rotate. The eccentric bearings 142 are connected to the input shaft 141 with their centers spaced apart from each other.The cycloid disks 143 are respectively installed on the eccentric bearings 142, and each of the eccentric bearings 142 is positioned at the center of the corresponding cycloid disk 143. That is, a pair of cycloid disks 143 are provided and are eccentrically rotated by the eccentric bearings 142.Such cycloid disks 143 are provided with a plurality of through holes 143' which are arranged radially around the centers of the cycloid disks 143. As shown in Figs. 3 to 5, each of the cycloid disks 143 is provided with eight through holes 143' spaced apart from each other. The number of through holes 143' may be increased or decreased depending on the capacity of the cycloid disks 143, and an output pin 153 is inserted into each of the through holes 143' to compensate for the eccentricity of the centers of the cycloid disks 143.On the outer circumferential surface of each of the cycloid disks 143, a lobe having a continuous cycloid curve is provided. A split ring 147 is interposed between the cycloid disks 143 to space the cycloid disks apart.The ring gear case 144 is disposed so as to surround the cycloid disks 143 at a certain distance therefrom. On the inner peripheral surface of the ring gear housing 144, a plurality of rollers 145 are installed to cause the cycloid disks 143 to rotate by contacting the outer peripheral surfaces of the cycloid disks 143, i.e., the lobes. The rollers 145 are installed on ring pins 145' rotatably installed along the inner circumferential surface of the ring gear housing 144 at a constant interval, and are in contact with the outer circumferential surfaces of the cycloid disks 143. The ring gear housing 144 is fixed to the motor housing 180 by coupling bolts 148 as described later, and thus rotation of the ring gear housing 144 is prevented.The output shaft 151 serves to receive the reduced rotational force from the cycloid disks 143 and transmit the rotational force to the axle 120. The output shaft 151 has a predetermined length and is provided with a shaft 151 acoupled to the axle 120 and a flange 151 bextending from the end of the shaft 151 ain the radial direction. On the rear side of the flange 151b, a plurality of output pins 153 inserted into respective through holes 143' are installed. It is obvious that the number of output pins 153 is equal to that of the through holes 143'.In addition, on the front side of the output shaft 151 and the rear side of the ring gear housing 144, there are respectively disposed an output housing 152 and an input housing 146 provided with hollow portions 152' and 146' through which the output shaft 151 and the input shaft 141 can pass. The output housing 152 and the input housing 146 serve to protect the components of the above-described cycloid reducer 140. The output housing 152, the input housing 143, and the ring gear housing 144 are coupled by the coupling bolts 148. Since the coupling bolts 148 are fixed to the front housing 181 of the motor housing 180, rotation of the ring gear housing 144 is prevented.Reference numeral 149 denotes a ball bearing installed between the input shaft 141 and the output shaft 151 to prevent the rotational force of the input shaft 141 from being directly transmitted from the output shaft 151, reference numeral 155 denotes a hub bearing installed between the output housing 152 and the axle 120, reference numeral 115 denotes a flange nut coupled to the end of the output shaft 151.In the above-described cycloid reducer 140, the cycloid disks 143 are in contact with the rollers 145 in the ring gear housing 144 to perform rotation about their center and revolution rotation when the eccentric bearings 142 rotate, which are connected to the input shaft 141 that rotates together with the rotor 134 of the wheel-housed motor 130. For example, when the cycloid disks 143 are rotated clockwise by the eccentric bearings 142, the cycloid disks 143 rotate clockwise about their center while rotating counterclockwise in engagement with the rollers 145. That is, the torque of the cycloid disks 143 corresponds to the number of decreased output rotations, and thus by using this mechanism, the decreased rotational force is transmitted to the axle 120 via the output shaft 151. Since rocking of the cycloid disks 143 is cancelled by connecting the output pins 153 to the through holes 143' of the cycloid disks 143, the axis 120 and the shaft 151a are aligned with each other when they are rotated by the rotational force received from the output shaft 151.That is, when the wheel-housed motor 130, the cycloid reducer 140, and the axle 120 are connected in series to boost the driving force of the wheel-housed motor 130 by the cycloid reducer 140 and transmit the boosted driving force to the axle 120, the cycloid reducer 140 is installed in the wheel-housed motor 130, and the wheel-housed motor 130 is positioned inside the wheel 110. This can reduce the overall size of the engine system housed in the wheel as compared with conventional cases. Therefore, damage to the in-wheel motor 130 can be prevented by external impacts, and since the unsprung mass is reduced, the driving safety of the vehicle can be improved, installation of the in-wheel motor system can be simplified, and freedom of design can be further improved by increased usability of an installation space.In order to stably fix the motor system 100 accommodated in the wheel to the vehicle, the TBA assembly 200 is used in the assembling process.FIG. 6 is an exploded perspective view illustrating the attachment structure for the in-wheel motor system according to the embodiment of the present invention, and FIG. 7 is a cross-sectional view illustrating the arrangement of FIG. 6.Referring to FIGS. 6 and 7, a mounting structure for the wheel-mounted motor system according to the illustrated embodiment of the present invention includes the wheel-mounted motor system 100 mounted in the wheel 110 of a vehicle and the vehicle-mounted TBA assembly 200 with the wheel-mounted motor 100 installed thereon.The TBA assembly 200 to attach the wheel-housed engine system 100 to the vehicle includes a drag arm 210 coupled to the engine housing 180 forming the outer appearance of the wheel-housed engine system 100, and a bracket 220 for attaching the drag arm 210 to a vehicle body. Reference numeral 230 denotes a shock absorber, a device used for stabilizing the vehicle body by damping the elastic action of a spring. Since the shock absorber is a known technology, a detailed description thereof will be omitted.The drag arm 210 is provided with a through hole 215 surrounding the step portion 185 of the motor housing 180. The diameter of the through hole 215 may be the same as that of the step portion 185. Also, a plurality of mounting holes 218 are formed in the drag arm 210 in the radial direction of the through hole 215 and are disposed at positions corresponding to those of the through holes 188 formed in the motor housing 180. Accordingly, when the step portion 185 is slidably inserted into the through hole 215 to combine the motor housing 180 with the drag arm 210, the step portion 185 is held by the through hole 215, and the mounting surface 186 of the motor housing 180 is in close contact with the drag arm 210. Here, it is apparent that the fixing holes 188 formed in the motor housing 180 are aligned with the coupling holes 218.When the motor housing 180 is combined with the tow arm 210 as described above, the motor housing 180 is fixed to the tow arm 210 by the fixing bolts 240. That is, by screw-coupling the fastening bolts 240 to the fastening holes 188 through the coupling holes 218, the motor housing 180 is fastened.In addition, FIGS. 6 and 7 illustrate that six fastening holes 188 and six coupling holes 218 are provided and are combined by the fastening bolts 240, but embodiments of the present invention are not limited thereto. The respective number of the attachment holes 188 and the coupling holes 218 may be selectively decreased or increased to stably attach the motor housing 180.The bracket 220 is integrally formed with the tow arm 210 and coupled to the vehicle body by separate bolts (not shown).Since the in-wheel engine system 100 is allowed to be mounted or detached by the fastening bolts 240 fastened to or removed from the TBA assembly 200 fastened to the vehicle body, the in-wheel engine system 100 can be easily mounted and detached without interference with other components. Also, since a plurality of fastening bolts 240 are coupled to the motor housing 180 together with the drag arm 210 to allow the drag arm 210 to surround the motor housing 180, the fastening area can be increased, and the combination can be stably maintained.As is apparent from the above description, a mounting structure for a wheel-mounted motor system according to embodiments of the present invention can increase the mounting contact area in mounting a motor housing of the wheel-mounted motor system to a vehicle, thereby ensuring the effectiveness of assisting the coupling between the wheel-mounted motor and the vehicle against vibration and shock.Second, the engine system housed in the wheel can be easily installed on and detached from the vehicle without hindrance from other components.Third, the design freedom can be improved by securing a space for a cycloid reducer and the motor housed in the wheel.Fourth, by attaching the motor accommodated in the wheel to a wheel such that the motor accommodated in the wheel is positioned in the wheel, the motor accommodated in the wheel can be protected from impacts from an external object, and damage to the motor accommodated in the wheel can be prevented.Finally, since a miniaturized compact motor system accommodated in the wheel is provided, the unsprung mass can be reduced, and thereby the driving safety can be increased.Therefore, as compared with conventional cases where a washer is used or a stopper is fixed to the upper side of opposite ends of the bypass passage, the overall length of the shock absorber can be reduced, and thus waste of raw materials can be reduced.

Claims

A mounting structure for a wheel-mounted motor system (100) for installing the wheel-mounted motor system (100) in a vehicle, comprising: the wheel-mounted motor system (100) installed in a wheel (110) of the vehicle for generating a rotational force for driving the wheel (110); and a torsion bar axle (TBA) assembly (200) for mounting the wheel-mounted motor system (100) to a vehicle body, wherein: a rear part of a motor housing (180) forming an outer appearance of the wheel-mounted motor system (100) includes a step portion (185) formed in a step manner to have a reduced diameter and an annular mounting surface (186) vertically disposed from the step portion (185); The TBA assembly (200) includes: a drag arm (210) provided with a through hole (215) surrounding the step portion (185) of the motor housing (180); a bracket (220) integrated with the drag arm (210) to fix the drag arm (210) to a vehicle body; and a plurality of fixing bolts (240) for fixing the motor housing (180) to the drag arm (210), wherein when the step portion (185) is fitted and coupled to the through hole (215), the fixing surface (186) is in close contact with the drag arm (210).The mounting structure according to claim 1, wherein a plurality of mounting holes (188) are formed at a constant interval along an outer circumferential surface of the mounting surface (186) of the motor housing (180), and a plurality of coupling holes (218) are formed at the respective positions of the mounting holes (188) in a radial direction of the through hole (215) of the drag arm (210) such that the mounting bolts (240) are screw-connected to the mounting holes (188) through the coupling holes (218).The mounting structure according to claim 1, wherein the motor system (100) accommodated in the wheel includes: an accommodated motor (130) provided with a rotor (134) and a stator (135) located in a space formed in the wheel (110) for generating a rotational force for driving the wheel (110), wherein the rotor (134) and the stator (135) are arranged to face each other to define an accommodation space (131) therebetween; a cycloid reducer (140) installed in the accommodation space (131) of the motor (130) accommodated in the wheel and provided with an output shaft (151) for transmitting a decreased rotation amount to an axle (120) installed on the wheel (110) and an input shaft (141) for penetrating the motor (130) accommodated in the wheel to rotate together with the rotor (134); a disc (160) installed at an end of the input shaft (141) protruding through the motor (130) accommodated in the wheel; a disc brake (170) for applying a braking force to the disc (160); and the motor housing (180) provided with a front housing (181) surrounding a front part of the motor (130) accommodated in the wheel and having an open center, and a rear housing (182) surrounding a rear part of the motor (130) accommodated in the wheel and coupled to the front housing (181).The mounting structure according to claim 3, wherein the cycloid reducer (140) includes: the input shaft (141) fixed by the rotor (134) to rotate with the rotor (134); a pair of eccentric bearings (142) connected to the input shaft (141) to eccentrically transmit the rotation of the input shaft (141); a pair of cycloid disks (143) installed respectively on the eccentric bearings (142), each of the eccentric bearings (142) being positioned at a center of the respective cycloid disk (143), and provided with a plurality of through holes (143') formed radially around the center of each of the cycloid disks (143) to eccentrically rotate the cycloid disks (143); a ring gear case (144) installed to surround the cycloid disks (143), and provided with a plurality of rollers (145) installed at a constant interval along an inner circumferential surface of the ring gear case (144) to be in contact with outer circumferential surfaces of the cycloid disks (143) to allow the cycloid disks (143) to perform a revolving rotation and a rotation about the center of the cycloid disks (143); and the output shaft (151) is coupled to the axle (120) to rotate together with the axle (120), and provided with a plurality of output pins (153) inserted into the respective through holes (143') to compensate for the eccentricity of the center of the cycloid disks (143).The mounting structure according to claim 4, wherein an output housing (152) and an input housing (146) having hollow portions (152', 146') for allowing the output shaft (151) and the input shaft (141) to pass therethrough, respectively, are further provided at a front portion of the output shaft (151) and a rear portion of the ring gear housing (144), respectively, the output housing (152), the input housing (146), and the ring gear housing (144) are coupled by a plurality of coupling bolts (148), and the coupling bolts (148) are fixed to the motor housing (180) to prevent rotation of the ring gear housing (144).The mounting structure according to claim 4, wherein the output shaft (151) is provided with a shaft (151a) coupled to the axle (120) and a flange (151b) extending from an end of the shaft (151) in a radial direction of the shaft (151), the output pins (153) being installed on a rear side of the flange (151b).

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