Wheel systems for vehicles, vehicles and wheel rims

Abstract

A wheel system for a vehicle is provided, comprising a stator, a rotor, a rotary bearing, and an in-wheel motor. The in-wheel motor includes a motor stator and a motor rotor. The rotor is coupled to the stator via a rotary bearing for rotation about a rotation axis. The motor stator is connected to the stator. The motor rotor is coupled to the motor stator for cooperation with the motor stator to generate an electromagnetic force to rotate the rotor relative to the stator about the rotation axis. The motor stator has a center extending therethrough and defining a center plane perpendicular to the rotation axis. The center plane has an inboard and outboard side. In driving use, the inboard side faces toward the center of the vehicle, and the outboard side faces away from the center of the vehicle. The rotor has a mounting surface configured to be connected to a wheel rim. The mounting surface is located on the inboard side. The rotor connects the mounting surface to the stator via only the inboard side.

Description

Technical Field

[0001] The present invention relates to a wheel system for a vehicle, a vehicle including the wheel system, and a wheel rim used in the wheel system.

[0002] The project leading to this application has received funding from the European Union's Horizon 2020 research and innovation program under grant agreement No. 848620.

Background Art

[0003] Wheel systems for vehicles have been known for centuries, but there is ongoing development to improve existing wheel systems.

[0004] A wheel system is typically connected to a suspension system having springs and dampers. One side of the suspension system is connected to the vehicle chassis. The other side of the suspension system supports the wheel system. The suspension system at least partially isolates the chassis from vibrations and forces generated by traveling over uneven surfaces such as bumps and holes.

[0005] An important characteristic of a wheel system is the so-called unsprung mass. The unsprung mass is the combined mass of the components supported by the suspension system, for example, the combined mass of the rotor, rim, and tire. In some cases, part of the suspension system is included in the unsprung mass. Since the unsprung mass is located between an uneven surface, such as a road surface, and the suspension system, the suspension system cannot isolate the unsprung mass from vibrations and forces generated by traveling over an uneven surface. When traveling over a bump, only the tire provides some isolation with respect to the unsprung mass.

[0006] When driving over a bump, the unsprung mass is accelerated forcefully upward, while the chassis is accelerated much more slowly due to the suspension system. Because the unsprung mass is accelerated forcefully upward, a large contact force can be generated between the road surface and the rim. This contact force is particularly large when driving over a steep bump at high speed. Large contact forces can cause damage to the tire, such as leakage, and / or damage to the rim, such as plastic deformation or cracking. The smaller the unsprung mass, the smaller the contact force for a particular bump at a particular vehicle speed. For example, lightweight alloy rims with less mass have been developed than steel rims of the same size to reduce unsprung mass. Also, less unsprung mass typically improves vehicle handling and comfort.

[0007] Another ongoing development is the development of in-wheel motors. In-wheel motors are electric motors located inside the wheels. In-wheel motors have the advantage of significantly reducing the weight of the vehicle by eliminating the need for a transmission system. In addition, each wheel with an in-wheel motor can be controlled individually, improving the performance of the vehicle.

[0008] In-wheel motors are known from German patent application DE19548117A1 (Patent Document 1). Known in-wheel motors have a stator and a rotor. The rotor rotates relative to the stator along the motor axis. A rim is connected to the rotor via connecting bolts. A stack of magnets, coils, and sheet metal is provided to generate an electromagnetic force to rotate the rotor.

[0009] A known drawback of in-wheel motors is their large unsprung mass due to their placement within the wheel. The magnets and sheet metal stack are heavy components. Driving a vehicle equipped with a known in-wheel motor over uneven surfaces, such as over curbs or potholes, can cause damage to the tire, rim, or rotor. [Prior art documents] [Patent Documents]

[0010] [Patent Document 1] German Patent Application No. DE19548117A1 Specification [Overview of the project] [Problems that the invention aims to solve]

[0011] One objective of the present invention is to reduce the unsprung mass of the wheel system. [Means for solving the problem]

[0012] The object of the present invention is achieved by a wheel system for a vehicle comprising a stator, a rotor, a rotary bearing, and an in-wheel motor including a motor stator and motor rotor. The rotor is connected to the stator via a rotary bearing so as to rotate around a rotation axis. The motor stator is connected to the stator. The motor rotor is connected to the rotor so as to cooperate with the motor stator to generate an electromagnetic force that causes the rotor to rotate relative to the stator around a rotation axis. The motor stator has a center through which a central plane extends and perpendicular to the rotation axis is defined. The central plane has an inboard side and an outboard side. In driving use, the inboard side faces toward the center of the vehicle, and the outboard side faces away from the center of the vehicle. The rotor has a mounting surface configured to be connected to a wheel rim. The mounting surface is located on the inboard side. The rotor connects its mounting surface to the stator only via the inboard side.

[0013] A vehicle has a wheel system that supports the weight of the vehicle and guides it in a desired direction. Therefore, forces are applied between the road surface and the vehicle's chassis via the wheel system. The chassis, or at least a large portion of the chassis, is located on the inboard side. Therefore, by positioning the mounting surface on the inboard side and connecting the mounting surface to the stator only through the inboard side, forces between the road surface and the chassis are transmitted along the shortest possible path. Because these forces are transmitted along the shortest possible path, the rim and rotor require less material to transmit these forces with acceptable deformation and stress.

[0014] In comparison, in the known wheel motor of German patent application DE19548117A1, the rim is connected to the rotor's most outboard axial plane via connecting bolts. Rotary bearings closest to the most outboard axial plane support the rotor to the stator. The stator extends all the way through the in-wheel motor toward the suspension system. Due to the weight of the vehicle, radial forces are generated on the rim. These radial forces must first be transmitted from the rim toward the axial plane of the rim in the outboard direction. The radial forces are then transmitted from the rim toward the rotor's most outboard axial plane. Subsequently, the radial forces are transmitted from the rotor toward the most outboard portion of the stator and then toward the inboard direction. As a result, the rim and stator of the known in-wheel motor require far more material than the in-wheel motor according to the present invention to achieve acceptable deformation and stress.

[0015] The stator can be made shorter by positioning the mounting surface on the inboard side and by connecting the mounting surface to the stator only through the inboard side. The stator does not need to extend outboard to support the rotor via a rotating bearing. Instead, the stator only needs to extend far enough outboard to support the motor stator. In one example, the stator extends outboard to the in-wheel motor but does not support the rotor on the outboard side of the in-wheel motor, so it can have a lighter configuration than the stator of known in-wheel motors. Since the stator does not extend beyond the in-wheel motor outboard to support the rotor, the rotor does not support the rim on the outboard side. The rotor does not have any structures that transmit force from the rim to the stator through the outboard side. As a result, the rotor can be made lighter than the rotor of known in-wheel motors by removing material from the rotor on the outboard side. Some of the material removed from the outboard side can be added to reinforce the rotor on the inboard side. In the example, all the material removed from the outboard side is added to reinforce the rotor on the inboard side. As a result, instead of achieving a reduction in rotor mass, a rotor that is more resistant to damage or deformation is obtained.

[0016] Because the mounting surface is on the inboard side, the rim does not require an axial surface on the outboard side of the rim that is strong enough to support the weight of the vehicle. Instead, because the rim is mounted to the rotor more inboard, no material is required on the axial surface on the outboard side.

[0017] In the in-wheel motor according to the present invention, the stator is provided with, for example, a connection means for connecting to a vehicle's suspension system. For example, the stator has a mounting surface for bolting the stator to the body of the suspension system. The stator has, for example, a cylindrical shape. The suspension system has a circular opening for receiving the cylindrical shape of the stator. In another example, the suspension system has a shaft. The cylindrical shape of the stator is mounted on the shaft of the suspension system. The stator is integrated with the suspension system, for example. For example, the stator can be connected to a shock absorber.

[0018] The rotor is connected to the stator via a rotating bearing so as to rotate around the axis of rotation. The axis of rotation is the axis around which the wheel rotates, allowing the vehicle to move. In this patent application, terms such as “radial,” “axial,” and “tangential” refer to the axis of rotation unless otherwise specified. The expressions “radial direction” and “axial direction” refer to the direction relative to the axis of rotation, i.e., the radial direction and the axial direction relative to the axis of rotation, respectively. The axial direction is along the longitudinal direction of the axis.

[0019] The terms "inboard side" and "outboard side" are used to indicate the side of a component or surface that is closest to the center of the vehicle, or the side that is furthest from the center of the vehicle.

[0020] The rotor extends radially outward from the axis of rotation. In one example, the rotor radially surrounds the stator. An in-wheel motor is housed within an enclosure formed by the rotor. In one example, the rotor has a substantially disc shape. The disc shape extends radially. The disc shape extends, for example, from the rotating bearing through the inboard side of the stator to the mounting surface. For example, the mounting surface is configured as an axial surface of the disc shape. The axial surface faces at least partially in the axial direction of the axis. The motor rotor is coupled to the rotor on the axial surface of the disc shape. The mounting surface and the motor rotor are coupled to the same axial surface of the disc shape or to different axial surfaces of the disc shape. The rotor is axially symmetric or rotationally symmetric. In an example where the rotor is rotationally symmetric, the rotor is provided with ribs extending, for example, between the rotating bearing and the mounting surface. The rotor may have three, four, five, six, or any appropriate number of ribs. The ribs may provide radial and axial rigidity to the rotor. The rotor has, for example, a material that extends tangentially between the ribs and is thinner in the axial direction of the rotor than the ribs. The material can provide tangential rigidity to the rotor to transmit driving torque between the motor rotor and the wheel rim. The material is sufficiently suitable for transmitting driving torque because it extends tangentially between the ribs, even though it is thinner in the axial direction of the rotor than the ribs. In one example, the rotor has a cylindrical shape. The cylindrical shape has one side that is substantially closed by the axial face of the rotor. The axial face of the rotor is connected to a rotating bearing in the stator. The axial face is located at least partially on the inboard side of the stator. The axial face extends through the inboard side of the stator between the rotating bearing and the mounting surface. The axial face is provided with ribs, for example, to reinforce the axial face. The ribs extend, for example, radially. An in-wheel motor is located inside the cylindrical shape. For example, the motor rotor is located on the inner surface of the cylindrical shape.

[0021] A rotary bearing is a bearing that supports the rotor on the stator. A rotary bearing can be, for example, a roller bearing such as a tapered roller bearing or a needle roller bearing, or a ball bearing such as a double-row ball bearing. A rotary bearing is configured to allow the rotor to rotate relative to the stator around a rotation axis, and also to restrain the rotor relative to the stator in all other directions. For example, a rotary bearing can restrain the rotor relative to the stator radially, axially, and in a rotational direction perpendicular to the rotation axis. A rotary bearing may be a single bearing or include multiple bearings, such as two bearings. Multiple bearings are arranged at a distance from each other along the rotation axis, for example, to better restrain the rotor relative to the stator in a rotational direction perpendicular to the rotation axis. In the case of multiple bearings, the rotor is configured to connect its mounting surface to the multiple bearings only via the inboard side. The rotor does not connect its mounting surface to any one of the multiple bearings via the outboard side of the stator.

[0022] An in-wheel motor is an electric motor that generates an electromagnetic force. An in-wheel motor has a motor stator and a motor rotor. The electromagnetic force is generated by the interaction of the magnetic fields of the motor stator and the motor rotor. The magnetic field of one of the motor stator and motor rotor is generated by an electric coil. By applying an electric current through the electric coil, the electric coil generates a magnetic field. The magnetic field of the other of the motor stator and motor rotor is generated by a permanent magnet, a ferromagnetic material, a further electric coil, or a combination thereof. The magnetic fields of the ferromagnetic material and the further electric coil can be induced by the electric field generated by the electric current passing through the electric coil.

[0023] Considering providing an electric wire, the motor stator does not rotate relative to the chassis so that the motor rotor can rotate. Therefore, it is easier to supply current to the electric coil in the motor stator. In that example, the motor rotor is provided with a permanent magnet, a ferromagnetic material, and / or an electric coil having no wire connection with the chassis. In the chassis, a power source such as a battery supplies current to the electric coil. When the motor rotor includes the electric coil to which current is supplied, for example, slip rings are provided to bring current from the power source to the motor rotor. In another example, current is supplied to the electric coil in the motor rotor by induction.

[0024] The motor stator has a center that defines a central plane. The central plane extends through the center and is perpendicular to the rotation axis. The central plane extends through the center of the motor stator. For example, the motor stator extends parallel to the rotation axis from a first edge of the motor stator to a second edge of the motor stator. The center is a point along the rotation axis to the middle between the first edge and the second edge. In one example, the motor stator includes a plurality of electric coils, and the central plane extends through the centers of the electric coils. In another example, the motor stator includes a plurality of arrays of electric coils. The electric coils in the array are arranged in a tangential direction along the motor stator. The arrays are arranged adjacent to each other in a direction parallel to the rotation axis. In that example, the central plane passes through the center defined by the most inboard edge of the most inboard array and the most outboard edge of the most outboard array.

[0025] The central plane has an inboard side facing toward the center of the vehicle. Most or all of the vehicle's chassis is located on the inboard side of the central plane. For example, the vehicle's cabin is on the inboard side of the central plane. The central plane also has an outboard side facing away from the center of the vehicle. The outboard side is opposite the inboard side of the central plane. When viewed from the central plane toward the outboard side, parts of the chassis are not visible at all or very much. If a closed wheel arch is applied, the closed wheel arch is the portion of the chassis that may be located on the outboard side of the central plane. In some embodiments, the inboard side of the central plane faces the location where the suspension system connects to the chassis. In some embodiments, the inboard side of the central plane faces the suspension.

[0026] The rotor is provided with an attachment surface to which a wheel rim can be attached. The attachment surface is a surface that contacts the surface of the wheel rim for placing the wheel rim on the rotor. For example, screw holes are provided in the attachment surface. Wheel bolts can clamp the wheel rim to the attachment surface. In another example, a threaded rod is provided in the attachment surface. When the wheel rim is attached to the attachment surface, the threaded rod penetrates through a hole in the wheel rim. A wheel nut is arranged on the threaded rod so as to clamp the wheel rim to the attachment surface. For example, the attachment surface is provided with alignment features for concentrically aligning the wheel rim with the rotor. The alignment features include, for example, one or more protrusions on the attachment surface and / or one or more recesses on the attachment surface. The alignment features on the attachment surface cooperate with the alignment features on the wheel rim, such as protrusions or recesses. The alignment features on the attachment surface are formed, for example, by the shape of the screw holes or the threaded rod. The screw holes or the threaded rod may have a conical surface that cooperates with the conical surface of the wheel bolt or the wheel nut. In this example, the wheel bolt or the wheel nut not only clamps the wheel rim to the attachment surface but also concentrically aligns the wheel rim with respect to the rotor. In another example, the attachment surface is a conical surface that cooperates with the conical surface of the wheel rim to concentrically align the wheel rim with the rotor. The attachment surface includes a single surface for contacting the wheel rim or a plurality of separated surfaces for contacting the wheel rim. For example, the attachment surface includes three separated surfaces that are radially arranged around the axis of rotation at an angle of 120° to each other.

[0027] The attachment surface is arranged on the inboard side of the central plane. This means that the attachment surface is more on the inboard side than the central plane of the motor stator. The attachment surface is closer to the center of the vehicle than the central plane of the motor stator.

[0028] The rotor connects to the stator via its mounting surface only on the inboard side. Therefore, the rotor extends from the rotating bearing through the inboard side of the stator to the mounting surface. The rotor has no portion that extends from the rotating bearing through the outboard side of the stator to the mounting surface.

[0029] In one embodiment, the mounting surface is located radially outward from the motor rotor.

[0030] According to this embodiment, the electromagnetic force driving the vehicle is generated by the cooperation of the motor rotor and motor stator. The electromagnetic force acts on the motor rotor, and the same electromagnetic force acts on the motor stator in the opposite direction. The electromagnetic force needs to be transmitted from the motor rotor to the wheel rim, and through the wheel rim to the tire, and through the tire to the road surface. Since the tire supports the vehicle on the road surface with the radial surface of the tire, the wheel rim and tire are positioned radially outward from the motor rotor. This makes it possible to position the in-wheel motor radially inward from the tire and wheel rim. By positioning the mounting surface radially outward from the motor rotor, the electromagnetic force is transmitted from the motor rotor to the tire along the shortest possible path. The electromagnetic force is directed radially outward from the motor rotor to the mounting surface. The electromagnetic force is transmitted from the mounting surface to the wheel rim, and through the wheel rim to the tire. Since the electromagnetic force is transmitted radially outward from the motor rotor to the mounting surface, it does not need to be transmitted to any part of the rotor that is radially inward from the motor rotor. The portion of the rotor between the mounting surface and the motor rotor may be constructed with more material to transmit electromagnetic force, without requiring more material to be used on the radially inward side of the motor rotor, while reducing stress and deformation of the rotor.

[0031] In one embodiment, the motor stator includes a plurality of coils. The coils are configured to cooperate with the motor rotor to generate an electromagnetic force under the control of the current flowing through them. The central plane extends through the center of the coil.

[0032] In this embodiment, multiple electrical coils are provided. The electrical coils are further referred to as “coils.” The central plane extends through the center of the coil. For example, multiple coils are arranged tangentially along the motor stator. The centers of all coils are located in the same axial position on the axis of rotation. The rotor connects its mounting surfaces to the stator only via the inboard side of the central plane, which is on the inboard side of the multiple coils. The rotor does not connect its mounting surfaces to the stator via the outboard side of the multiple coils. In one example, the rotor is configured such that the outboard side of the motor stator does not face any part of the rotor in a direction parallel to the axis of rotation.

[0033] By supplying current through multiple coils, an electromagnetic force is generated between the coils in the motor stator and motor rotor. This electromagnetic force is sometimes called the Lorentz force. The motor rotor is equipped with coils, permanent magnets, or ferromagnetic materials that work in cooperation with the coils in the motor stator to generate the Lorentz force. To accelerate the vehicle, a large current is applied to the coils to generate a large electromagnetic force. To maintain the vehicle at a constant speed, a small current is applied to the coils to generate an electromagnetic force sufficient to compensate for wind and / or rolling resistance and / or elevation differences in the road surface. To decelerate the vehicle, the current can be reversed to generate an electromagnetic force in the opposite direction. Optionally, in-wheel motors are used as generators during vehicle deceleration, with the in-wheel motors generating current stored in the vehicle's battery.

[0034] In one embodiment, the motor rotor includes multiple magnets that work together with multiple coils to generate an electromagnetic force.

[0035] According to this embodiment, an electromagnetic force is generated by the interaction between the magnets of the motor rotor and the coils of the motor stator. This interaction occurs because a magnetic flux is generated in the gap between the magnets and the coils. The gap, which is not completely blocked and is preferably as small as possible, is typically called the flux bearing gap. The stronger the magnetic flux in the flux bearing gap, the stronger the electromagnetic force. The magnetic flux is determined by the strength of the magnetic field generated by the permanent magnets and the amount of current flowing through the coils. The flux bearing gap should be large enough not to block the flux bearing gap when the wheel system is in operation, for example, when it hits a curb. Safety measures may be taken to prevent the flux bearing gap from being accidentally blocked. The reluctance of the in-wheel motor is optionally reduced by placing a ferromagnetic material, such as back iron or iron teeth, near the permanent magnets. Back iron is a component that includes iron or any other ferromagnetic material. Multiple magnets are placed, for example, on the back iron on the side opposite to the side of the magnets facing the coils. For example, due to the superior permeability of ferromagnetic materials compared to air, the magnetic flux across the flux bearing gap can be increased by using iron or any other suitable ferromagnetic material.

[0036] In one embodiment, the in-wheel motor is either an axial flux motor or a radial flux motor.

[0037] In an axial flux motor, the flux bearing gap is positioned axially. In the example of coils and permanent magnets in the motor stator, this means the following: The coils and magnets are positioned offset from each other along the axial direction. The coils and magnets are positioned facing each other in the axial direction. The magnetic flux propagates axially across the flux bearing gap as a result. In one example, there are two flux bearing gaps, one on each side of the motor stator along the axial direction. In this example, there are two magnet arrays. Each magnet array faces one side of the motor stator. The coils of the motor stator are positioned axially between the two magnet arrays. The rotor is positioned, for example, to support the magnets of the motor rotor on the outboard side of the motor stator. Therefore, a portion of the rotor may be on the outboard side of the motor stator. However, the portion of the rotor that is on the outboard side of the motor stator does not connect its mounting surface to the stator.

[0038] In a radial flux motor, the flux bearing clearance is arranged radially. In the example of coils in the motor stator and permanent magnets in the motor rotor, this means the following: The coils and magnets are arranged offset from each other along the radial direction. The magnets in the motor rotor are arranged radially outward from the coils in the motor stator. The coils and magnets are arranged to face each other radially. The magnetic flux consequently propagates radially across the flux bearing clearance.

[0039] In one embodiment, the wheel system includes a cover plate connected to the rotor. The cover plate is positioned on the outboard side of the center plane. The cover plate is configured to cover the in-wheel motor in the axial direction.

[0040] According to this embodiment, the cover plate covers the in-wheel motor on the outboard side of the stator. The inboard side of the in-wheel motor is at least partially covered by the rotor, as the rotor connects its mounting surface to the stator on the inboard side of the motor stator. However, the rotor may not completely cover the in-wheel motor in the axial direction on the outboard side, but only partially. Considering the assembly of the in-wheel motor, it is beneficial that the rotor does not cover the in-wheel motor in the axial direction on the outboard side. This allows the in-wheel motor to be assembled within the rotor by moving the portion of the in-wheel motor towards the rotor axially toward the inboard side. However, during operation and use of the wheel system, the in-wheel motor needs to be protected from the ingress of liquids (e.g., rain), debris, and impacts. Also, because the in-wheel motor is a high-pressure component, safety measures are required to prevent someone from accidentally touching the electronic components of the in-wheel motor, for example, when changing a tire. The cover plate is provided to protect the in-wheel motor from water and dust, and to provide safety measures to prevent anything from accidentally touching the in-wheel motor. The cover plate may be, for example, a disc-shaped or conical plate. Alternatively, the cover plate may have a cylindrical shape. The end faces of the cylindrical shape cover the in-wheel motor axially. The sides of the cylindrical shape cover the in-wheel motor radially. There is no direct connection between the cover plate and the stator, as the rotor connects its mounting surface to the rotary bearing only on the inboard side of the motor stator. Instead, the cover plate is connected to the stator via the rotor and rotary bearing through the inboard side of the motor stator.

[0041] The cover plate is provided with mounting means for attaching the cover plate to the rotor, for example, at the edge of the cover plate. The mounting means include fasteners such as bolts and nuts that allow the cover plate to be removed from the rotor. This allows access to the in-wheel motor if the in-wheel motor requires repair. The fasteners include, for example, at least one lock nut or lock bolt that requires a special tool to remove the lock nut or lock bolt from the rotor. This can ensure that only qualified persons have access to the in-wheel motor. If the in-wheel motor is not expected to require repair, or requires it rarely, the cover plate may be glued to the rotor. To remove the cover plate from the rotor in case of repair, the adhesive must be cut, peeled off, or removed.

[0042] The cover plate may be provided with a reinforcing structure, for example. The reinforcing structure provides additional material to the cover plate to give it further strength. The reinforcing structure helps prevent or limit deformation of the cover plate when it is struck by an object, for example, in an accident, or when it hits an object on the road surface. For example, the reinforcing structure is a rib structure in which multiple ribs are arranged radially. The ribs extend, for example, from the center of the cover plate to the edge of the cover plate, near the mounting means to which the cover plate is connected to the rotor. The rib structure is arranged, for example, rotationally symmetrically around the axis of rotation. In another example, the reinforcing structure provides a cover plate with a thicker thickness at the center and a cover plate with a thinner thickness near the edge of the cover plate. In this example, the reinforcing structure provides additional rigidity to limit deformation of the center of the cover plate in the axial direction. In one example, the reinforcing structure has a combination of ribs and a rib-shaped structure to provide additional rigidity to the cover plate. The rigidity of the cover plate increases the rigidity of the rotor, for example. For example, the rigidity of the cover plate helps limit radial deformation of the rotor even when the vehicle is under heavy load. In another example, the rigidity of the cover plate helps reduce the noise-vibration-harshness (NVH) behavior of the vehicle. The reinforcing structure is, for example, an integrated part formed by casting or molding a cover plate having the reinforcing structure as a single piece of the cover plate. In another example, the reinforcing structure is attached to the cover plate, for example by welding, bolting, or bonding.

[0043] In one embodiment, the rotor surrounds the stator radially.

[0044] In this embodiment, the rotor surrounds the stator. In this way, a space is defined between the rotor and the stator to accommodate the in-wheel motor. As a result, a wheel system is obtained that efficiently uses the space to accommodate the rotor, stator, and in-wheel motor. Preferably, the rotor has the largest possible diameter. By providing a rotor with the largest possible diameter, the motor rotor can be positioned in the largest possible diameter. The larger the diameter in which the motor rotor is positioned, the more torque the in-wheel motor can provide. Preferably, the rotating bearing is positioned in the smallest possible radial position. By positioning the rotating bearing in the smallest possible radial position, any frictional force generated by the rotating bearing due to the rotation of the rotor relative to the stator is also in the smallest possible radial position. Because the frictional force is in the smallest possible radial position, it causes only a small loss of driving torque from the wheel system.

[0045] In one embodiment, the wheel system comprises a brake system having a brake disc and a caliper. The brake disc is connected to a rotor. The brake disc and caliper are configured to contact each other at the force position to generate a braking force. The mounting surface is located radially outward from the force position.

[0046] According to this embodiment, the brake disc and caliper work together to generate a braking force that decelerates the vehicle. The caliper is actuated, for example, hydraulically, pneumatically, electronically, or mechanically to contact the brake disc. When the caliper contacts the brake disc, a braking force is generated between the caliper and the brake disc, for example by contacting the brake disc on both opposing sides. As the caliper and brake disc move relative to each other while the braking force is being generated, energy is dissipated. Due to the dissipated energy, the vehicle loses kinetic energy and decelerates. The braking force needs to be transmitted from the rotor to the wheel rim, through the wheel rim to the tire, and through the tire to the road surface. Since the tire supports the vehicle on the road surface with the radial surface of the tire, the wheel rim and tire are positioned radially outward from the brake disc. By positioning the mounting surface radially outward from the brake disc, the braking force is transmitted from the brake disc to the tire along a short path. The braking force is directed radially outward from the brake disc to the mounting surface. Braking force is transmitted from the mounting surface to the wheel rim, and then through the wheel rim to the tire. Since the braking force is transmitted radially outward from the brake disc to the mounting surface, it does not need to be transmitted to any part of the rotor that is radially inward of the brake disc. The part of the rotor between the mounting surface and the motor rotor may be constructed with more material to transmit the braking force while reducing rotor stress and deformation, without requiring additional material to be added to the rotor radially inward of the brake disc.

[0047] In one embodiment, at least a portion of the rotating bearing is positioned closer to the center plane than the mounting surface is positioned to the center plane.

[0048] According to this embodiment, the rotary bearing and mounting surface are not in the same axial position. Instead, the rotary bearing is positioned closer to the center plane of the motor stator than the mounting surface is positioned to the center plane of the motor stator. This has the advantage that the mounting surface can be positioned axially farther in the inboard direction. This reduces the amount of material required for the rotor to transmit the force acting on the wheel rim through the inboard side of the motor stator to the rotary bearing. For example, if the mounting surface is positioned far enough away from the center plane, the portion of the rotor that starts radially inward from the mounting surface may be straight. This straight shape is particularly well suited to transmitting radial forces with low stress and minimal deformation. The rotary bearing is positioned more toward the center plane than the mounting surface, and this can be beneficial for several reasons. By positioning the rotary bearing more toward the center plane of the motor stator, the rotary bearing is, for example, more aligned with the center of the wheel rim. The more aligned the rotary bearing is with the center of the wheel rim, the lower the bending moment caused by the weight of the vehicle will be in the direction perpendicular to the axis of rotation at the rotary bearing. This allows for the use of a smaller and / or less expensive rotary bearing. Another example is that this frees up space for the wheel system or other components of the vehicle. For instance, by positioning the rotary bearings more towards the center plane, space can be created to accommodate mounting plates for attaching the stator to the suspension system. This can reduce the axial dimension of the wheel system.

[0049] In one embodiment, the wheel system comprises a wheel rim. The wheel rim includes two bead seats for holding a tire. The wheel rim defines a rim center plane in the radial direction of the wheel rim. The two bead seats are arranged symmetrically on opposite sides of the rim center plane. The wheel rim includes a mounting body configured to connect to a mounting surface. The mounting body is at least partially positioned on the inboard side of the rim center plane.

[0050] According to this embodiment, the two bead sheets provide the surfaces on which the tire is held by the wheel rim. The two bead sheets are the surfaces on which the edges of the tire's sidewalls contact after the tire has been inflated. One sidewall contacts one bead sheet. Each of the two bead sheets is adjacent to a radially extending projection, such as a flange of the wheel rim, to prevent the tire from moving axially away from the bead sheet. The bead sheets are arranged symmetrically with respect to the rim center plane, i.e., the axial distance between the rim center plane and one of the bead sheets is the same as the axial distance between the rim center plane and the other bead sheet. Since the tire has a symmetrical cross-section, the rim center plane aligns with the center of the tire. The wheel rim does not need to be perfectly symmetrical with respect to the rim center plane. For example, the wheel rim may have more material or extend more on one side of the rim center plane than on the other side. In another example, a complete wheel rim is symmetrical with respect to the rim center plane. The mounting body is the portion of the wheel rim configured to connect to the mounting surface. The mounting body has a surface for contacting the mounting surface. The mounting body is provided with, for example, through holes for accommodating bolts to clamp the mounting body to the mounting surface. The through holes are, for example, for accommodating threaded rods extending from the mounting surface, so that nuts can cooperate with the threaded rods to clamp the mounting body to the mounting surface. The mounting body is positioned at least partially on the inboard side of the rim center plane to shorten the path through which force is transmitted from the tire to the suspension system. This allows the wheel system to be manufactured with less material while maintaining acceptable stress and deformation caused by the forces acting on the tire.

[0051] In one embodiment, the rotary bearing is positioned aligned with the rim center plane.

[0052] According to this embodiment, the rotary bearing is aligned with the center of the tire. This has the advantage that the radial force acting on the tire, caused by the weight of the vehicle, is aligned with the rotary bearing. As a result, the bending moment perpendicular to the axis of rotation is absent or negligible in the rotary bearing due to the weight of the vehicle. This allows for the use of less expensive and / or smaller rotary bearings. To withstand large bending moments, the rotary bearing has large dimensions along the axis of rotation, for example, to provide sufficient bending stiffness. The large dimensions reduce the force on the rotary bearing caused by large bending moments. However, with respect to small or no bending moments, the dimensions of the rotary bearing along the axis of rotation can be reduced.

[0053] In one embodiment, the wheel system includes fasteners such as wheel nuts for clamping the mounting body between the mounting surface and the fasteners. The wheel rim includes a rim well. The rim well is located between the bead seats. At least a portion of the fasteners is located on the outboard side of the rim well.

[0054] The fasteners include wheel nuts or wheel bolts or any other type of fasteners that can clamp the mounting body to the mounting surface. The fasteners are preferably easily removable so as to allow the tire to be changed. For example, the vehicle user should be able to remove the fasteners to change the wheel rim with a flat tire, or change a wheel rim with a summer tire to a wheel rim with a winter tire, and vice versa. One or more fasteners include, for example, a lock nut or lock bolt that can only be removed using a special tool. This helps to prevent the wheel rim from being stolen. The wheel rim has a radially outward-facing surface. The bead seat is part of the radially outward-facing surface. The cross section of the radially outward-facing surface faces the inside of the tire when the tire is mounted on the wheel rim. The cross section of the radially outward-facing surface also forms the rim well. The rim well is the surface that is radially inward of the bead seat. The rim well extends for several centimeters, for example, 5 cm, 10 cm, or 15 cm along the axial direction. The rim well is located several centimeters radially inward from the bead seat, for example, 2 cm, 5 cm, or 10 cm. The rim well can assist in mounting and removing the tire from the wheel rim. The rim well can help provide sufficient rigidity and flexibility to the wheel rim. By positioning part of the fastener on the outboard side of the rim well, there is more space for that part of the fastener. For example, a fastener includes a wheel bolt having a wheel bolt shaft and a wheel bolt head. The wheel bolt head has a larger diameter than the wheel bolt shaft. The wheel bolt shaft extends through the mounting body to the mounting surface. The mounting body extends radially inward from the rim well. The wheel bolt head is configured to clamp against the mounting body on the outboard side of the rim well. Because the rim well is the radially inward portion of the radially outward-facing surface, there is more space on the outboard side of the rim well for the wheel bolt head.Furthermore, there is more space for a socket wrench to be applied to the wheel bolt to tighten or loosen it. The same advantage applies in examples where the threaded rod extends from the mounting surface through the mounting body, and the wheel nut is applied to the threaded rod to clamp the mounting body to the mounting surface. The space on the outboard side of the rim well is used to accommodate wheel nuts that have a larger diameter than the threaded rod. Also, the space on the outboard side of the rim well is used to accommodate a socket wrench for tightening or loosening the wheel nut. By positioning part of the fastener on the outboard side of the rim well, there is more radial space for positioning an in-wheel motor in a larger diameter, resulting in a more efficient in-wheel motor.

[0055] In one embodiment, the wheel rim includes a wheel cap. The wheel cap is positioned on the outboard side of the rim center plane. The wheel cap is configured to axially cover at least a portion of the internal space radially enclosed by the wheel rim.

[0056] According to this embodiment, the wheel cap is provided to cover an internal space radially enclosed by the wheel rim. The wheel cap completely or partially covers the internal space axially. When the wheel cap completely covers the internal space axially, the wheel cap has, for example, a sealed disc shape that extends beyond the radial position of the mounting surface from the axis of rotation. The sealed disc shape is configured, for example, to prevent dust or water from entering the internal space from the outside of the internal space in order to allow the wheel cap to pass through. The sealed disc shape is configured, for example, to improve the aerodynamics of the wheel system. When the wheel cap partially covers the internal space axially, the wheel cap has, for example, a plurality of ribs with open spaces between them. The ribs are configured, for example, to protect components within the internal space. The rigidity and strength of the ribs are configured to prevent objects from entering the internal space. Objects could be, for example, debris on the road surface or tree branches that are accidentally struck while driving the vehicle. In one example, the wheel cap has a sealed disc shape reinforced by ribs. The wheel cap includes one or more parts. For example, a wheel cap has a main portion that covers most of the internal space. The main portion has holes that reach fasteners that clamp the wheel rim to the mounting surface. The wheel cap has a further portion that covers the holes in the main portion. The further portion can be easily removed to access the fasteners, for example, to replace the wheel rim. Thus, when removing the wheel rim, only a small portion of the wheel cap needs to be removed. The wheel cap is connected to the wheel rim, for example, on the mounting body, such as on the inboard side of the mounting body and / or on the outboard side of the mounting body. For example, the wheel cap is fastened to the mounting body by fasteners that are arranged alternately with the fasteners that fasten the mounting body to the mounting surface. This example utilizes the structural strength already available in the mounting body. Thus, the wheel rim requires little to no additional material to support the wheel cap. In one example, the wheel cap is not connected to the wheel rim at the rim center plane.This has the advantage that the wheel cap does not add rigidity to the edge of the wheel rim. When a vehicle drives over a curb or other sharp protrusion, a large contact force may be applied to the edge of the wheel rim. The flexibility of the wheel rim edge reduces such a large contact force. By mounting the wheel cap on the rim center plane, it is prevented that the wheel cap will increase the rigidity of the wheel rim edge. By preventing an increase in the rigidity of the wheel rim edge, large contact forces or large peak stresses can be prevented.

[0057] In one embodiment, the wheel cap includes a central hole for balancing the wheel rim in a balancing machine.

[0058] According to this embodiment, the central hole in the wheel cap is configured to position the wheel rim on a balancing machine. The balancing machine grips the wheel rim through the central hole in the wheel cap and rotates the wheel rim. The balancing machine measures the center of gravity of the combination of the wheel rim, wheel cap, and tire. Based on the measured center of gravity, the balancing machine indicates the position and amount of balancing weights to place. After applying the balancing weights, the center of gravity is at the center of the central hole in the wheel cap. The central hole in the wheel cap represents the center of the wheel rim, defined by the mounting body. The advantage of the central hole in the wheel cap is that it is possible to balance the wheel rim according to the present invention using a conventional balancing machine. Conventional balancing machines are configured to balance known wheel rims with small diameter central holes. However, the mounting body of the wheel rim according to the present invention is positioned much radially outward than the small diameter central hole of conventional wheel rims. By providing the central hole in the wheel cap, the wheel rim according to the present invention can be balanced on a conventional balancing machine without the need for further tools. In one example, a wheel cap includes an additional portion that covers the center hole when the vehicle is in use. This additional portion can be removed from the center hole when balancing the wheel rim.

[0059] In one embodiment, a vehicle is provided that includes the wheel system described above.

[0060] According to this embodiment, a wheel system according to the present invention is provided on a vehicle such as an automobile, truck, bus, or motorcycle. Preferably, the vehicle has a single-sided wheel suspension system. This means that the suspension system holds the stator only on the inboard side of the wheel system and not on the outboard side. This allows for easy access to the wheel rim and tire via the outboard side. For example, the wheel rim can be easily installed and removed via the outboard side. In comparison, a double-sided wheel suspension system holds the stator on both sides of the wheel rim. To replace the wheel rim, a portion of the double-sided wheel suspension needs to be disassembled.

[0061] The vehicle may, for example, have a battery to power the in-wheel motors. For example, the vehicle may have solar panels to power the battery and the in-wheel motors. The vehicle's electronics may, for example, be configured to use the in-wheel motors as generators when the vehicle needs to decelerate. The electronics may be configured to generate an electric current using the kinetic energy of the moving mass of the vehicle. The electric current charges the battery.

[0062] In one embodiment, a wheel rim for use in the wheel system described above is provided.

[0063] According to this embodiment, the wheel rim is configured to be mounted on the mounting surface of the rotor. The mounting body of the wheel rim is positioned at an appropriate radial location to cooperate with the mounting surface of the rotor. Optionally, the wheel rim includes a wheel cap with a central hole for balancing the wheel rim in a conventional balancing machine, for example.

[0064] The present invention will be described in more detail below with reference to the drawings illustrating exemplary embodiments of the invention, without limitation. [Brief explanation of the drawing]

[0065] [Figure 1A] This is a diagram of a wheel system according to one embodiment of the present invention. [Figure 1B] This is a diagram of a wheel system according to one embodiment of the present invention. [Figure 2] Figure 1 is a detailed diagram of the wheel system according to the embodiment shown in Figure 1. [Figure 3] This is a further detailed view of the wheel system according to the embodiment shown in Figure 1. [Figure 4] This is a cross-sectional view of a wheel system according to a second embodiment of the present invention. [Figure 5] This is a cross-sectional view of a wheel system according to a third embodiment of the present invention. [Figure 6] This is a diagram of a wheel system according to a fourth embodiment of the present invention. [Figure 7] This is a diagram of a wheel system according to a fourth embodiment of the present invention. [Modes for carrying out the invention]

[0066] Figures 1A and 1B show a wheel system 100 according to one embodiment of the present invention. The wheel system 100 is connected to a suspension system 102. The suspension system 102 connects the wheel system 100 to the vehicle chassis. The vehicle chassis is represented by reference numeral 104.

[0067] The suspension system 102 has two arms 106 and a shock absorber 108. The arms 106 are pivotally connected to the chassis so as to allow the wheel system 100 to move relative to the chassis. The shock absorber 108, which may include a damper and a coil spring, has one end connected to the upper arm 106. The other end of the shock absorber 108 is connected to the lower arm 106. When driving over an uneven surface, the position of the arms 106 changes relative to each other. As a result, the length of the shock absorber 108 changes, causing the shock absorber 108 to generate a reaction force. By generating a reaction force, the shock absorber 108 limits the transmission of vibrations from the wheel system 100 to the chassis while keeping the wheel system 100 in contact with the road surface as well as possible.

[0068] The wheel system 100 includes a stator 120, a rotor 130, a wheel rim 140, and a tire 150. The stator 120 is connected to the suspension system 102 via a suspension body 114. The rotor 130 is connected to the stator 120 via a rotating bearing 160. The rotating bearing 160 allows the rotor 130 to rotate relative to the stator 120 around a rotation axis 112. The rotation axis 112 is perpendicular to the direction of vehicle operation. The wheel rim 140 is connected to the rotor 130. The tire 150 is mounted on the wheel rim 140.

[0069] Figure 2 shows a detailed view of the wheel system 100 according to the embodiment of Figure 1. Figure 2 shows a cross-sectional view of the wheel system 100 comprising a stator 120, a rotor 130, and a rotary bearing 160. The rotor 130 is connected to the stator 120 via the rotary bearing 160. The wheel system 100 has an in-wheel motor 210 including a motor stator 212 and a motor rotor 214. The rotor 130 is connected to the stator 120 via the rotary bearing 160 so as to rotate around the rotation axis 112. The motor stator 212 is connected to the stator 120. The motor rotor 214 is connected to the rotor 130 so as to generate an electromagnetic force in cooperation with the motor stator 212 to rotate the rotor 130 relative to the stator 120 around the rotation axis 112. The motor stator 212 has a center through which a central plane 216 extends and is perpendicular to the rotation axis 112 is defined. The central surface 216 has an inboard side 202 and an outboard side 204. In operation, the inboard side 202 faces toward the center of the vehicle, and the outboard side 204 faces away from the center of the vehicle. The rotor 130 has a mounting surface 232 configured to connect to the wheel rim 140. The mounting surface 232 is located on the inboard side 202. The rotor 130 is configured to connect the mounting surface 232 to the rotary bearing 160 only via the inboard side 202.

[0070] Figure 2 shows that the rotor 130 does not connect its mounting surface 232 to the rotary bearing 160 via the outboard side 204. There is no portion of the rotor 130 that extends from the mounting surface 232 to the rotary bearing 160 via the outboard side 204. Instead, the rotor 130 extends from the mounting surface 232 to the rotary bearing 160 only via the inboard side 202.

[0071] Three distinct parts can be defined with respect to the rotor 130. The rotor 130 has a first part 131, a second part 132, and a third part 133. The first part 131 is connected to the rotating bearing 160 and extends radially outward. The first part 131 also extends in the inboard direction in the axial direction. By extending in the inboard direction, the rotor 130 extends beyond the axial position of the motor stator 212 on the inboard side. The second part 132 of the rotor 130 begins adjacent to the first part 131 at the axial position of the motor stator 212 on the inboard side. The second part 132 extends radially outward and includes a mounting surface 232. The second part 132 can extend radially outward because the first part 131 is at a sufficient distance from the center surface 216 so that the second part 132 does not collide with the motor stator 212. The second part 132 has multiple holes. Only one hole is shown in Figure 2. Each hole is provided with a threaded rod 234. The third portion 133 of the rotor 130 extends axially from the second portion 132 to the outboard side 204. The third portion 133 is shaped cylindrical and radially encloses the internal space. The third portion 133 of the rotor 130 radially encloses the stator 120. The internal space houses the in-wheel motor 210. A cover plate 238 is provided on the edge of the third portion 133 on the outboard side of the rotor 130. The cover plate 238 is positioned on the outboard side 204 of the center plane 216. The cover plate 238 is configured to axially cover the in-wheel motor 210. The cover plate 238 encloses the axial opening of the internal space.

[0072] The wheel rim 140 includes a radially outward-facing surface. The radially outward-facing surface has a bead seat 258 and a rim well 256. The bead seat 258 is radially outward of the rim well 256. Adjacent to the rim well 256, a mounting body 240 is positioned radially inward of the rim well 256. The wheel rim 140 includes a mounting body 240 for connecting the wheel rim 140 to the mounting surface 232 on the rotor 130.

[0073] The threaded rod 234 cooperates with the wheel nut 242 to form a fastener, which clamps the mounting body 240 between the mounting surface 232 and the fastener.

[0074] The wheel rim 140 defines a rim center plane 252 in the radial direction of the wheel rim 140. Two bead seats 258 are symmetrically arranged on opposing sides of the rim center plane 252. The mounting body 240 is at least partially positioned on the inboard side of the rim center plane 252. As shown in Figure 2, the rotary bearing 160 has a mounting surface 232 that is closer to the rim center plane 252 than the rim center plane 252. In one embodiment, the rotary bearing 160 is aligned with the rim center plane 252.

[0075] A wheel cap 254 is provided on the wheel rim 140. The wheel cap 254 is connected to the wheel rim 140 at the outboard edge of the wheel rim 140. The wheel cap 254 is positioned on the outboard side of the rim center surface 252. The wheel cap 254 is configured to axially cover at least a portion of the internal space radially enclosed by the wheel rim 140.

[0076] The in-wheel motor 210 includes a motor stator 212 positioned on the stator 120 and a motor rotor positioned on the rotor 130. The motor stator 212 extends radially outward from the stator 120 and includes a coil 260. The motor rotor 214 extends radially inward from a third portion 133 of the rotor 130 and includes a magnet 262. The coil 260 and the magnet 262 are radially offset from each other. This radial offset forms a radial flux bearing clearance 264. In this embodiment, the in-wheel motor 210 is a radial flux motor.

[0077] The motor rotor 214 is mounted on the inner surface of the third portion 133 of the rotor 130. The magnet 262 is mounted on the back iron 266. The back iron 266 is connected to the third portion 133 of the rotor 130. In another embodiment, the rotor 130 does not have the third portion 133. Instead, the motor rotor 214 is configured to be mounted on the second portion 132 of the rotor 130. In this embodiment, the motor rotor 214 radially surrounds the stator 120. Optionally, a cover plate 238 is connected to the edge of the motor rotor 214.

[0078] The coil 260 of the motor stator 212 is connected to a wire provided on the stator 120. The stator 120 has a hollow section for housing the wire. The wire provides a drive signal that connects the coil 260 to a battery and / or a control unit to operate the in-wheel motor 210.

[0079] The wheel nuts 242 have a conical shape that cooperates with the conical shape of the mounting body 240. When the wheel nuts 242 are tightened, their conical shapes cooperate to radially align the wheel rim 140 with the rotor 130.

[0080] A brake disc 268 is mounted on the inboard side of the rotor 130. The brake disc 268 is connected to the rotor 130 so as to rotate with the rotor 130 relative to the stator 120. The brake disc 268 works in cooperation with a caliper, which is not shown in Figure 2. The caliper contacts the brake disc 268 on the radially extending portion of the brake disc 268. As shown in Figure 2, the mounting surface 232 is located radially outward of the brake disc 268, and therefore the mounting surface 232 is radially outward of the contact point where the brake disc 268 and the caliper contact and generate braking force.

[0081] Figure 3 shows a further detailed view of the wheel system 100 according to the embodiment shown in Figure 1.

[0082] The cover plate 238 is provided with projections 310 extending radially from the cover plate 238. Each projection 310 has a hole for receiving a bolt. The projections 310 of the cover plate 238 correspond to projections of the rotor 130 that extend radially outward from a third portion of the rotor 130. Each of the projections of the rotor 130 is provided with a threaded hole for receiving a bolt. The bolts are inserted into the holes of the projections 310 of the cover plate 238 and into the threaded holes of the projections of the rotor 130 to clamp the cover plate 238 to the rotor 130. Depending on the axial rigidity of the cover plate 238 and the available space, the cover plate 238 is provided with enough projections 310 for three bolts, six bolts, ten bolts, or any other suitable number of bolts. The wheel nuts 242 are accessible through openings in the wheel rim 140. This allows the wheel rim 140 to be mounted to and removed from the mounting surface 232.

[0083] The mounting surface 232 is implemented as a plurality of projections extending radially outward from the rotor 130. In this case, there are 10 projections. These projections have holes for housing threaded rods 234, so that they can be clamped to the mounting body 240 of the wheel rim 140 by wheel nuts 242.

[0084] The wheel rim 140 is provided with a wheel cap 254 formed as an integral part of the wheel rim 140. The wheel cap 254 includes five spokes. The spokes extend radially inward from the outer ring 300 to the center of the wheel rim 140. The projections of the mounting body 240 and the spokes are positioned tangentially offset from each other. This allows a socket wrench to reach the wheel nuts 242 on the threaded rod 234, which is positioned through holes in the projections of the mounting body 240.

[0085] Because the mounting body 240 is positioned precisely radially outward, the mounting body 240 is incompatible with conventional balancing machines. Therefore, a central hole 330 is provided in the center of the wheel cap 254. The central hole 330 coincides with the central hole of a conventional wheel rim 140. As a result, the wheel rim 140 according to the present invention can be balanced on a conventional balancing machine. In one embodiment, an additional wheel cap portion is provided to cover the central hole 330 and the space between the spokes when the wheel rim 140 is mounted on the wheel system 100.

[0086] Figure 4 discloses a cross-section of a wheel system 100 according to a second embodiment of the present invention. The second embodiment is the same as the first embodiment, except as disclosed below. In this embodiment, the first portion 131 of the rotor 130 extends axially outboard so that the rotary bearing 160 is radially aligned with the rim center plane 252. The rotary bearing 160, the rim center plane 252, and the center plane 216 are substantially radially aligned with each other. In one embodiment, the rotary bearing 160, the rim center plane 252, and the center plane 216 are perfectly radially aligned with each other. As a result, optimal use of the rotor 130 material is obtained for transmitting radial forces in the tire 150 to the stator 120.

[0087] The mounting body 240 extends axially from the mounting surface 232 on the inboard side 202 to the outboard side 204. Similarly, the threaded rod 234 extends from the mounting surface 232 on the inboard side 202 to the outboard side 204. Thus, the wheel nut 242 is located on the outboard side 204 when the wheel nut 242 clamps the wheel rim 140 to the mounting surface 232. The wheel nut 242 is at least partially located on the outboard side of the rim well 256. Because the wheel rim 140 has a larger radius dimension on the outboard side of the rim well 256, space is available for the wheel nut 242 and for a wrench to tighten or loosen the wheel nut 242. Furthermore, by providing the mounting surface 232 on the inboard side of the rim well 256, there is space available to extend the second portion 132 of the rotor 130 radially to provide sufficient material to support the threaded rod 234. By utilizing these available spaces, the magnets 262 of the in-wheel motor 210 can be positioned in the largest possible radial position.

[0088] In an alternative embodiment, the wheel cap 254 is connected to the wheel rim 140 at the rim center plane 252. The wheel rim 140 includes, for example, a threaded hole for cooperating with a bolt that clamps the wheel cap 254 to the wheel rim 140 at the rim center plane 252. The threaded hole in the wheel rim 140 for clamping the wheel cap 254 is tangentially located between the through holes of the mounting body 240 for mounting the wheel rim 140 to the rotor 130. Alternatively, the wheel cap 254 has a hole for cooperating with some or all of the threaded rods 234 of the rotor 130. After the wheel rim 140 is positioned on the rotor 130, the cover plate 238 is positioned by aligning the hole in the wheel cap 254 with the threaded rods 234. The corresponding wheel nuts 242 are then applied and tightened. In this way, the wheel nuts 242 clamp the wheel rim 140 to the rotor 130 and the wheel cap 254 to the wheel rim 140.

[0089] Figure 5 discloses a wheel system 100 according to one embodiment of the present invention. The wheel system 100 of Figure 5 is the same as the wheel system 100 according to the embodiments described above, except that the wheel rim 140 includes an outer ring 500. The outer ring 500 has a radially outward-facing surface 510. The radially outward-facing surface 510 has a bead seat 258 and a rim well 256. The rim well 256 extends radially inward from the bead seat 258. The outer ring 500 has two flanges 520 to ensure that the tire 150 stays on the bead seat 258.

[0090] A mounting body 540 is positioned radially inward of the rim well 256. In this embodiment, the mounting body 540 is implemented as a ring extending radially inward from the rim well 256. The ring is provided with a hole for housing a threaded rod 234. When the wheel rim 140 is clamped to the mounting surface 232, one side of the ring contacts the wheel nut 242, while the other side of the ring contacts the mounting surface 232.

[0091] Figures 6 and 7 show a fourth embodiment according to the present invention. The fourth embodiment has the same features as described in the other embodiments, except that they will be further described. The fourth embodiment has a wheel rim 140 having a mounting body 540 which is implemented as a ring, as in the third embodiment. The mounting body 540 is located radially inward of the rim well 256. The mounting surface 232 is not shown in Figure 6 because the cross section is taken in a location where the mounting surface 232 is not present. The wheel cap 654 is configured to be connected to the mounting body 540 by bolts 600. For example, nuts are provided on the inboard side adjacent to the mounting body 540 so as to cooperate with the bolts 600 to clamp the wheel cap 654 to the mounting body 540. In another example, threads are provided in holes in the mounting body 540 for receiving the bolts 600. The wheel cap 654 extends axially to the inboard side 202 to reach the mounting body 540, while axially covering the cover plate 238 on the outboard side 204. The wheel cap 654 is optionally centered on the axis of rotation 112 by contacting the radially outer surface of the third portion 133 of the rotor 130.

[0092] As shown in Figure 7, the wheel cap 654 has five spokes. A bolt 600 is provided at one end of each spoke for clamping the wheel cap 654 to the mounting body 450. The other end of each spoke is near the center hole 730. The center hole 730 is configured to balance the wheel rim 140 in a conventional balancing machine with the wheel cap 654 attached to the wheel rim 140.

[0093] The wheel cap 654 may be combined with any one of the disclosed embodiments.

[0094] One of the wheel nuts 242, shown in Figure 7, used to clamp the wheel rim 140 to the mounting surface 232, is spaced tangentially offset from the bolt 600. In this way, the wheel rim 140 can be clamped between the wheel nut 242 and the mounting body 540, and the wheel cap 654 can be clamped between the bolt 600 and the mounting body 540.

[0095] Where necessary, this specification describes detailed embodiments of the invention. However, it should be understood that the disclosed embodiments are for illustrative purposes only, and that the invention may also be carried out in other forms. Accordingly, the specific structural aspects disclosed herein should not be considered limiting to the invention, but merely as a basis for the claims and as a basis for considering the invention as implementable by a person skilled in the art.

[0096] Furthermore, the various terms used in this explanation should not be considered restrictive, but rather as a comprehensive description of the present invention.

[0097] As used herein, the term "a" means one or more unless otherwise specified. The phrase "a plurality of" means two or more. The terms "comprising" and "having" constitute open language and do not exclude the presence of more elements.

[0098] The reference numerals in the claims should not be construed as limiting to the present invention. No particular embodiment is required to achieve all the objectives described.

[0099] The mere fact that specific technical means are mentioned in various dependent claims still allows for the possibility that combinations of these technical means may be applied advantageously. [Explanation of Symbols]

[0100] 100 Wheel System 102 Suspension System 104 Chassis 106 Arm, upper arm, lower arm 108 Shock Absorbers 112 Rotation axis 114 Suspension body 120 stator 130 rotor 131 Part 1 132 Part 2 133 Part 3 140 Wheel Rim 150 tires 160 Rotary bearing 202 Inboard side 204 Outboard side 210 In-wheel motor 212 Motor Stator 214 Motor Rotor 216 Center plane 232 Mounting surface 234 Screw Rod 238 Cover Plate 240 Mounting Unit 242 Wheel nuts 252 Rim center surface 254 Wheel caps 256 Limwell 258 Bead Sheet 260 coils 262 Magnets 264 Radial flux bearing clearance 266 Back Iron 268 Brake Disc 300 Outer ring 310 Protrusion 330 center hole 500 Outer ring 510 Radially outward-facing surface 520 flange 540 Mounting Unit 600 volts 654 Wheel Cap 730 center hole

Claims

1. A wheel system (100) for a vehicle, Stator (120) and, Rotor (130) and, Rotary bearing (160), An in-wheel motor (210) including a motor stator (212) and a motor rotor (214) Equipped with, The rotor (130) is connected to the stator (120) via the rotating bearing (160) so as to rotate around the rotating shaft (112), The motor stator (212) is connected to the stator (120), The motor rotor (214) is connected to the rotor (130) such that it works in cooperation with the motor stator (212) to generate an electromagnetic force that causes the rotor (130) to rotate around the rotation axis (112) relative to the stator (120). The motor stator (212) has a center that extends through the center and defines a central plane (216) perpendicular to the rotation axis (112), The central surface (216) has an inboard side (202) and an outboard side (204), In driving use, the inboard side (202) faces toward the center of the vehicle, and the outboard side (204) faces away from the center of the vehicle. The rotor (130) has a mounting surface (232) configured to be connected to the wheel rim (140), The mounting surface (232) is located on the inboard side (202), The rotor (130) connects the mounting surface (232) to the stator (120) only via the inboard side (202), The wheel system (100) comprises a wheel rim (140), the wheel rim (140) includes two bead seats (258) for holding a tire (150), the wheel rim (140) defines a rim center plane (252) in the radial direction of the wheel rim (140), the two bead seats (258) are symmetrically arranged on opposing sides of the rim center plane (252), the wheel rim (140) includes a mounting body (240) configured to connect to the mounting surface (232), the mounting body (240) is at least partially arranged on the inboard side of the rim center plane (252), The wheel system (100) is arranged such that the rotating bearing (160) is aligned with the rim center plane (252).

2. The mounting surface (232) is located radially outward of the motor rotor (214), as described in claim 1. The mounted wheel system (100).

3. The wheel system (100) according to claim 1 or 2, wherein the motor stator (212) includes a plurality of coils (260), the coils (260) configured to generate the electromagnetic force in cooperation with the motor rotor (214) under the control of the current passing through the coils (260), and the central plane (216) extends through the center of the coils (260).

4. The wheel system (100) according to claim 3, wherein the motor rotor (214) includes a plurality of magnets (262) for generating the electromagnetic force in cooperation with the plurality of coils (260).

5. The wheel system (100) according to any one of claims 1 to 4, wherein the in-wheel motor (210) is one of an axial flux motor and a radial flux motor.

6. The wheel system (100) according to any one of claims 1 to 5, comprising a cover plate (238) connected to the rotor (130), wherein the cover plate (238) is positioned on the outboard side (204) of the center surface (216), and the cover plate (238) is configured to cover the in-wheel motor (210) in the axial direction.

7. The wheel system according to any one of claims 1 to 6, wherein the rotor (130) radially surrounds the stator (120).

8. The wheel system (100) comprises a brake system having a brake disc (268) and a caliper, wherein the brake disc (268) is connected to the rotor (130), the brake disc (268) and the caliper are configured to contact each other at a force position to generate a braking force, and the mounting surface (232) is located radially outward from the force position, according to any one of claims 1 to 7.

9. A wheel system (100) according to any one of claims 1 to 8, wherein at least a portion of the rotating bearing (160) is positioned closer to the center surface (216) than the mounting surface (232) is positioned to be positioned to the center surface (216).

10. The wheel system (100) according to claim 1, wherein the wheel system (100) comprises fasteners such as wheel nuts (242) for clamping the mounting body (240) between the mounting surface (232) and the fasteners, and the wheel rim (140) includes a rim well (256) disposed between the bead seats (258), and at least a portion of the fasteners is disposed on the outboard side of the rim well (256).

11. The wheel system (100) according to any one of claims 1 to 10, wherein the wheel rim (140) includes a wheel cap (254), the wheel cap (254) is positioned on the outboard side of the rim center surface (252), and the wheel cap (254) is configured to axially cover at least a portion of the internal space radially enclosed by the wheel rim (140).

12. The wheel system (100) according to claim 11, wherein the wheel cap (254) includes a central hole (330) for balancing the wheel rim (140) in a balancing machine.

13. A vehicle comprising the wheel system (100) according to any one of claims 1 to 12.

14. A wheel rim (140) to be used in the wheel system (100) according to any one of claims 1 to 12.

Images