Rotor shaft system with increased rigidity

Abstract

A rotor shaft system for a vehicle comprises a rotor shaft with a first shaft end opposite a second shaft end. The rotor shaft has a first segment and a second segment defined between the first and second shaft ends. The rotor shaft system includes a gear connected to the rotor shaft between the first shaft end and the first segment, and a sleeve connected to the first segment such that it surrounds a portion of the gear. The rotor shaft system includes a lubrication system that extends at least partially through the rotor shaft and the sleeve. The lubrication system serves to supply a fluid to at least a portion of the rotor shaft and the sleeve.

Description

Technical area

[0001] The technical field generally refers to a drive system for a vehicle and in particular to a drive system for a vehicle with a rotor shaft system with increased stiffness. introduction

[0002] In general, the drive system of a vehicle, such as a hybrid or electric vehicle, may include an electric motor. The electric motor supplies energy to a transmission system, which in turn transfers the energy from the drive system to one or more of the vehicle's wheels. In certain applications, it is desirable to increase the speed of the electric motor. To increase the speed of the electric motor, the size of the rotor associated with the electric motor can be reduced, which leads to a corresponding reduction in the size of the rotor shaft associated with the electric motor. However, reducing the size of the rotor shaft can lead to increased flexibility of the rotor shaft. This increased flexibility can lead to decreased lateral stiffness of the rotor shaft, which is undesirable.

[0003] Accordingly, it is desirable to provide a rotor shaft system for an electric motor with increased stiffness, which provides a rotor shaft that enables higher rotational speeds for the electric motor without compromising the lateral stiffness of the rotor shaft. Furthermore, other desirable features and characteristics of the present disclosure will become apparent from the following detailed description and the accompanying claims in conjunction with the accompanying drawings and the preceding technical field and background. Description of the invention

[0004] According to various embodiments, a rotor shaft system is provided for a vehicle. The rotor shaft system comprises a rotor shaft with a first shaft end opposite a second shaft end. The rotor shaft has a first segment and a second segment defined between the first and second shaft ends. The rotor shaft system includes a gear coupled to the rotor shaft between the first shaft end and the first segment, and a shaft sleeve coupled to the first segment such that it surrounds a portion of the gear. The rotor shaft system includes a lubrication system that extends at least partially through the rotor shaft and the shaft sleeve. The lubrication system is configured to supply at least a portion of the rotor shaft and the shaft sleeve with a fluid.

[0005] The rotor shaft comprises a first shaft bore extending from the first shaft end through the first segment and at least a portion of the second segment, and the first shaft bore is in fluid communication with the lubrication system. The lubrication system comprises a transverse bore extending through the second segment and in fluid communication with the first shaft bore. The second segment contains a keyway defined axially on an outer circumference of the second segment, and the transverse bore is in fluid communication with the keyway. The keyway is configured to couple the rotor shaft to a rotor belonging to an electric motor of the vehicle. A lubrication line is defined through a portion of the first and second segments and is in fluid communication with the keyway. The shaft sleeve contains a sleeve lubrication bore that is in fluid communication with the lubrication line.The shaft sleeve encloses a recessed area formed in the first segment near the shaft gear. The first segment has a first diameter that is larger than the second diameter of the second segment. The rotor shaft system includes a shaft collar that is connected to the second segment near the second shaft end. The second segment contains a feed groove, and the shaft collar includes at least one opening that is in fluid communication with the feed groove.

[0006] According to various embodiments, a vehicle is also provided. The vehicle comprises an electric motor with a rotor and a rotor shaft system connected to the electric motor. The rotor shaft system comprises a rotor shaft with a first shaft end opposite a second shaft end. The rotor shaft has a first segment and a second segment defined between the first and second shaft ends. The second segment is coupled to the rotor. The rotor shaft system includes a gear mounted on the rotor shaft between the first shaft end and the first segment. The rotor shaft system also includes a shaft sleeve connected to the first segment such that it is positioned between the gear and the rotor, and the shaft sleeve surrounds a portion of the gear.The rotor shaft system includes a shaft collar connected to the second segment between the rotor and the second shaft end, and the shaft collar is configured to clamp the rotor and the shaft sleeve to the rotor shaft. The rotor shaft system includes a lubrication system defined by a portion of the rotor shaft and the shaft sleeve. The lubrication system is configured to supply fluid to at least the portion of the rotor shaft, the shaft sleeve, and the electric motor.

[0007] The rotor shaft comprises a first shaft bore extending from the first shaft end through the first segment and at least a portion of the second segment, and the first shaft bore is in fluid communication with the lubrication system. The lubrication system comprises a transverse bore extending through the second segment and in fluid communication with the first shaft bore. The second segment includes a keyway defined axially on an outer circumference of the second segment, the keyway being coupled to a key associated with the rotor, and the transverse bore being in fluid communication with the keyway. A lubrication line is defined through a portion of the first and second segments, and the lubrication line is in fluid communication with the keyway. The shaft sleeve includes a sleeve lubrication bore, and the sleeve lubrication bore is in fluid communication with the lubrication line.The shaft sleeve encloses a recessed area defined in the first segment adjacent to the shaft gear. The first segment has a first diameter larger than the second diameter of the second segment. The second segment includes a feed groove, and the shaft collar contains at least one opening in fluid communication with the feed groove. The vehicle includes a sensor connected to a second shaft bore at the second shaft end, and the second shaft bore extends axially toward the second segment. Brief description of the drawings

[0008] The exemplary embodiments are described below in conjunction with the following drawings, where the same reference numerals denote the same elements and where: Fig. Figure 1 is a functional block diagram showing a vehicle with a rotor shaft system with increased stiffness according to various embodiments; Fig. Figure 2 is a perspective front view of the rotor shaft system coupled to an electric motor which is connected to a drive system of the vehicle according to various embodiments; Fig. Figure 3 is a cross-sectional view of the rotor shaft system and the electric motor along line 3-3 of Fig. 2; Fig. Figure 4 is a perspective rear view of the rotor shaft system coupled to the electric motor in accordance with various embodiments; Fig. Figure 5 is an exploded view of the rotor shaft system and the electric motor according to various embodiments; and Fig. Figure 6 is a cross-sectional view of another exemplary rotor shaft system and the electric motor, taken from the perspective of line 3-3 of Fig. 2, for use with the vehicle of Fig. 1. Detailed description

[0009] The following detailed description is merely exemplary and is not intended to limit its application and use. Furthermore, it is not intended to be bound by any express or implied theory set forth in the preceding introduction, the description of the invention, or the following detailed description. As used herein, the term "module" refers to any hardware, software, firmware, electronic control component, processing logic, and / or processor device, individually or in any combination, including, but not limited to: application-specific integrated circuits (ASICs), an electronic circuit, a processor (common, dedicated, or as a group), and memory executing one or more software or firmware programs, a combinational logic circuit, and / or other suitable components providing the described functionality.

[0010] Embodiments of the present disclosure can be described herein in the form of functional and / or logical block components and various processing steps. Such block components can be implemented by any number of hardware, software, and / or firmware components configured to perform the specified functions. For example, an embodiment of the present disclosure may employ various integrated circuit components, such as memory elements, digital signal processing elements, logic elements, lookup tables, or the like, which can perform a variety of functions under the control of one or more microprocessors or other control devices.Furthermore, the person skilled in the art will understand that embodiments of the present disclosure can be used in conjunction with any number of systems and that the systems described here are merely exemplary embodiments of the present disclosure.

[0011] For the sake of brevity, conventional techniques related to signal processing, data transmission, signaling, control, machine learning models, radar, lidar, image analysis, and other functional aspects of the systems (and the individual operating components of the systems) are not described in detail herein. Furthermore, the connecting lines shown in the various figures are intended to represent exemplary functional relationships and / or physical couplings between the various elements. It should be noted that many alternative or additional functional relationships or physical connections may exist in an embodiment of this disclosure.

[0012] The term "axial" as used herein refers to a direction that generally runs parallel to or coincides with an axis of rotation, an axis of symmetry, or the centerline of a component or components. For example, in the case of a cylinder or disk with a centerline and generally circular ends or opposing faces, the "axial" direction may refer to the direction that generally extends parallel to the centerline between the opposing ends or faces. In certain cases, the term "axial" may be used in relation to components that are not cylindrical (or otherwise radially symmetrical). For example, the "axial" direction for a rectangular housing containing a rotating shaft may be considered to be a direction that generally runs parallel to or coincides with the axis of rotation of the shaft.Furthermore, the term "radial" as used here can refer to a direction or relationship of components with respect to a line extending outward from a common centerline, axis, or similar reference point, for example, in a plane of a cylinder or disk perpendicular to the centerline or axis. In certain cases, components may be considered to be "radially" aligned even if one or both components are not cylindrical (or otherwise radially symmetrical). Moreover, the terms "axial" and "radial" (and all terms derived from them) can also encompass directional relationships that are not exactly aligned with the actual axial and radial dimensions (e.g., oblique to them), provided that the relationship runs predominantly in the respective nominal axial or radial direction.The term "approximately" as used here means within 10% to account for manufacturing tolerances. Furthermore, the term "essentially" means a deviation of less than 10% to account for manufacturing tolerances.

[0013] In relation to Fig. 1 is a rotor shaft system with increased stiffness, generally represented as 100, connected to a vehicle 10 in accordance with various embodiments. In one example, the vehicle 10 is a battery-powered electric vehicle; however, it should be understood that the following disclosure may be applicable to other electrically driven devices. As in Fig. As shown in Figure 1, the vehicle 10 generally comprises a chassis 12, a body 14, front wheels 16, and rear wheels 18. The body 14 is mounted on the chassis 12 and essentially encloses the components of the vehicle 10. The body 14 and the chassis 12 can together form a frame. The vehicle wheels 16-18 are each rotatably connected to the chassis 12 near a corner of the body 14. In various embodiments, the vehicle 10 is an autonomous vehicle or a semi-autonomous vehicle. As can be seen, the rotor shaft system 100 can also be used in other non-autonomous systems and is not limited to the present embodiments.The vehicle 10 is shown in the illustrated embodiment as a battery-electric passenger car, but it should be recognized that any other vehicle, including motorcycles, trucks, sport utility vehicles (SUVs), motorhomes (RVs), etc., can also be used.

[0014] As shown, the vehicle 10 generally comprises a drive system 20, a transmission system 22, a steering system 24, a braking system 26, a sensor system 28, an actuator system 30, and at least one control unit 34. The drive system 20 may, in various embodiments, include an electric machine, such as an electric motor. The drive system 20 is coupled to the rotor shaft system 100, which in turn is coupled to the transmission system 22. The transmission system 22 is configured to transmit the power received from the drive system 20 via the rotor shaft system 100 to the vehicle wheels 16 and 18 according to selectable gear ratios. According to various embodiments, the transmission system 22 may include a continuously variable transmission (CVT), a stepped variable transmission, or another suitable transmission.

[0015] The braking system 26 is configured to exert a braking torque on the vehicle wheels 16 and 18. The braking system 26 can, in various embodiments, include friction brakes, a brake-by-wire system, a regenerative braking system such as an electric motor, and / or other suitable braking systems.

[0016] The steering system 24 influences the position of the vehicle wheels 16 and / or 18. Although a steering wheel 24a is shown for illustration, the steering system 24 may not include a steering wheel in some embodiments considered within the scope of the present disclosure.

[0017] The sensor system 28 comprises one or more detection devices 40a-40n that detect observable conditions of the external environment and / or the internal environment of the vehicle 10. In various embodiments, the sensor devices 40a-40n include, among others, radar devices (e.g., long-range, medium-range, and short-range), lidar devices, global positioning systems, optical cameras (e.g., forward-facing, 360-degree, rear-facing, side-facing, stereo cameras, etc.), thermal imaging cameras (e.g., infrared cameras), ultrasonic sensors, odometry sensors (e.g., encoders), and / or other sensors that can be used in conjunction with systems and methods according to the present subject matter.In one example, the sensor devices 40a-40n can include a shaft speed sensor 40a, which is coupled to the rotor shaft system 100 and configured to generate sensor signals based on the rotational speed of a rotor shaft 102 connected to the rotor shaft system 100. The sensor system 28 communicates with the control unit 34 via a communication medium.

[0018] The actuator system 30 comprises one or more actuator devices 42a-42n that control one or more vehicle functions, such as, but not limited to, the drive system 20, the transmission system 22, the steering system 24, and the braking system 26. In various embodiments, the vehicle 10 may also have internal and / or external vehicle features that are described in Fig. 1 not shown, such as various doors, a trunk and cabin features such as air, music, lighting, touchscreen display components, an active safety seat or a haptic seat and the like.

[0019] The control unit 34 comprises at least one processor 44 and a computer-readable storage device or medium 46. The processor 44 can be any custom or commercially available processor, a central processing unit (CPU), a graphics processing unit (GPU), an application-specific integrated circuit (ASIC) (e.g., a custom ASIC implementing a neural network), a field-programmable gate array (FPGA), an auxiliary processor among multiple processors connected to the control unit 34, a semiconductor-based microprocessor (in the form of a microchip or chipset), any combination thereof, or, more generally, any instruction-executing device. The computer-readable storage device or storage media 46 can include volatile and non-volatile memory, e.g., read-only memory (ROM), random-access memory (RAM), and keep-alive memory (KAM).KAM is a persistent or non-volatile memory that can be used to store various operating variables while the processor 44 is switched off. The computer-readable memory device(s) 46 can be implemented using any number of known memory devices such as PROMs (programmable read-only memory), EPROMs (electrical PROMs), EEPROMs (electrically erasable PROMs), flash memory, or other electrical, magnetic, optical, or combined memory devices capable of storing data, some of which represent executable instructions used by the control unit 34 in controlling the vehicle 10.

[0020] With reference to Fig. Section 2 describes the drive system 20 and the rotor shaft system 100 in more detail. As already mentioned, the drive system 20 in this example is an electric motor 50, which can have any suitable configuration for use with the vehicle 10. With brief reference to Fig. The electric motor 50 comprises a rotor 52 and a stator 54. The stator 54 surrounds the rotor 52 and includes two or more conductors that generate a magnetic field to rotate the rotor 52. The rotor 52 contains one or more magnets or conductors that also generate a magnetic field. The rotor shaft system 100 is coupled to the rotor 52 and rotates with it. The rotor shaft system 100 can be rotatably mounted by one or more bearings (not shown). The electric motor 50 can be contained between a pair of motor end rings 60, and the output shaft 56 can extend outwards from each of the motor end rings 60.

[0021] In this example, each of the motor end rings 60 is annular, and each of the motor end rings 60 is essentially mirror-symmetrical with respect to an axis perpendicular to a longitudinal axis L of the rotor shaft system 100. Each of the motor end rings 60 defines a central bore 62 and includes a countersunk area 64 defined around the central bore 62. The central bore 62 is dimensioned to accommodate a portion of the rotor shaft system 100 through it. The countersunk area 64 extends radially around the central bore 62. The countersunk area 64 forms a contact surface 64a for coupling the rotor shaft system 100 to the drive system 20. With reference to the Fig. 2 and Fig. 4 Each of the motor end rings 60 may also have one or more openings 66 defined around a circumference or periphery of the respective motor end rings 60 and spaced apart from the recessed area 64 which accommodates a respective mechanical fastening element, such as a bolt, screw, etc., to connect each of the motor end rings 60 to the stator 54.

[0022] In one example, the rotor shaft system 100 comprises the rotor shaft 102, a shaft sleeve 104, a shaft collar 106 ( Fig. 4) and a lubrication system 108. The rotor shaft 102 is made of a metal or metal alloy and is cast, forged, extruded, additively manufactured, etc. The rotor shaft 102 is essentially cylindrical and extends along the longitudinal axis L. The longitudinal axis L is also an axis of rotation of the rotor shaft 102. The rotor shaft 102 comprises a first shaft end 110 opposite a second shaft end 112, a shaft gear 114, a first segment or sleeve segment 116, a second segment or rotor segment 118, and a third segment or coupling segment 120. The rotor shaft 102 also defines a first shaft bore 122 and a second shaft bore 124. With reference to Fig. 3 defines the first shaft end 110 as having a first countersink 130, which is connected to the first shaft bore 122. The first shaft end 110 also includes a chamfer 132, which extends axially from the first shaft end 110. The first shaft end 110 can be coupled to a bearing, e.g., a ball bearing (not shown), which rotatably supports the rotor shaft 102. The second shaft end 112 defines a second countersink 134, which is connected to the second shaft bore 124.

[0023] The shaft gear 114 is defined on the rotor shaft 102, for example, by machining on a lathe. The shaft gear 114 is a pinion with a plurality of teeth 136. In this example, the shaft gear 114 is a helical pinion with a plurality of helical teeth. It should be noted that the shaft gear 114 on the rotor shaft 102 can be shaped as desired to fit the gear system 22. For example, the shaft gear 114 can be designed as a spur gear with a plurality of spur gear teeth, as a bevel gear with a plurality of bevel gear teeth, etc. In general, the shaft gear 114 is coupled to or engages with a mating gear M of the gear system 22 to transmit the torque from the drive system 20 to the gear system 22. Fig. 3) The shaft gear 114 can have any number of gear teeth 136 to couple with and drive the gear system 22, so that the number of gear teeth 136 shown here is merely an example. The shaft gear 114 is arranged on the rotor shaft 102 between the first shaft end 110 and the sleeve segment 116. In one example, the shaft gear 114 has a gear diameter GD, and the gear diameter GD is approximately 41 millimeters (mm) to approximately 42 millimeters (mm).

[0024] The sleeve segment 116 is defined on the rotor shaft 102 directly adjacent to the shaft gear 114. The sleeve segment 116 is defined between the shaft gear 114 and the rotor segment 118. Generally, the shaft sleeve 104 is connected to the rotor shaft 102 such that it is positioned above and connected to the sleeve segment 116. The sleeve segment 116 includes a recessed area 138, a lubrication groove 142, and part of a lubrication line 144. The recessed area 138 is located near or adjacent to the shaft gear 114. The recessed area 138 allows contaminants, such as metal shavings, etc., generated during the manufacture of the shaft gear 114, to be removed from the rotor shaft 102. In other words, the recessed area 138 serves as a cleaning area. A remainder of the sleeve segment 116 has a first diameter which is dimensioned and shaped in such a way as to connect the shaft sleeve 104 with the rotor shaft 102.In one example, the first diameter D1 is approximately 38.5 millimeters (mm) to approximately 40.5 millimeters (mm). The remainder of the sleeve segment 116 extends axially over a distance that allows alignment between the lubrication groove 142 and a sleeve lubrication bore 146. The lubrication groove 142 is connected to and in fluid communication with the sleeve lubrication bore 146 and the lubrication line 144. The lubrication groove 142 is defined along an axis that is substantially perpendicular to the longitudinal axis L, or it is defined radially to the rotor shaft 102. As will be discussed later, the lubrication groove 142 guides a fluid F, such as a lubricating fluid and / or a cooling fluid, etc. B. Oil, to the sleeve lubrication bore 146 of the shaft sleeve 104. As will be explained below, the lubrication line 144 extends along the rotor shaft 102 from the lubrication groove 142 of the sleeve segment 116 to near the second shaft end 112.The lubrication line 144 is coupled to or in fluid communication with the lubrication groove 142 in order to direct or supply the fluid F into the lubrication groove 142.

[0025] The rotor segment 118 is defined as extending from the sleeve segment 116 to the coupling segment 120. The rotor segment 118 has a second diameter D2, which differs from and is smaller than the first diameter D1 of the sleeve segment 116. A shoulder 147 is defined between the step or change in the diameter of the rotor shaft 102 from the sleeve segment 116 to the rotor segment 118. In one example, the second diameter D2 is approximately 36 millimeters (mm) to approximately 38 millimeters (mm). The rotor segment 118 is coupled to the rotor 52 of the electric motor 50. In this example, the rotor segment 118 includes a keyway 148 and a transverse bore 150. The keyway 148 extends axially along an outer surface or circumference of the rotor segment 118 and engages with a key 152 formed on the rotor 52.The interaction between the keyway 148 and the key 152 connects the rotor shaft 102 to the rotor 52 to enable torque transmission between the rotor 52 and the rotor shaft 102. The key 152 is located in the keyway 148. Fig. Figure 3 illustrates this. Thus, the rotor segment 118 is generally coupled to the rotor 52 so that it is driven by the rotor 52. The shaft sleeve 104 and the shaft collar 106 can also contribute to connecting the rotor shaft 102 to the rotor 52 along the rotor segment 118. The transverse bore 150 is defined as being substantially equidistant from the pair of motor rings 60. The transverse bore 150 is substantially cylindrical and extends along an axis that is substantially perpendicular to the longitudinal axis L. The transverse bore 150 is in fluid communication with, or fluidically coupled to, the first shaft bore 122 to receive the fluid F, and the transverse bore 150 is in fluid communication with, or fluidically coupled to, the lubrication line 144 to direct the fluid F into the lubrication line 144. The transverse bore 150 is also in fluid communication with the keyway 148 in order to direct the fluid F into the keyway 148.

[0026] In one example, the rotor segment 118 also includes a feed groove 154. The feed groove 154 is defined around an outer circumference of the rotor segment 118 near the coupling segment 120. The feed groove 154 is fluidically connected to, or fluidically coupled to, the keyway 148 to receive the fluid F from the keyway 148. The feed groove 154 delivers the fluid F to the motor end ring 60 near the second shaft end 112 and to the shaft collar 106.

[0027] The coupling segment 120 is defined between the rotor segment 118 and the second shaft end 112. In one example, the coupling segment 120 has a third diameter that differs from and is smaller than the second diameter D2 of the rotor segment 118. The coupling segment 120 is dimensioned to accommodate a bearing, such as a ball bearing. In this example, the coupling segment 120 includes a coupling groove 156. The coupling groove 156 is dimensioned and shaped to support the coupling of the bearing with the rotor shaft 102, thereby supporting the rotor shaft 102 for rotation. The coupling groove 156 is defined at essentially equal distances between the rotor segment 118 and the second shaft end 112.

[0028] The first shaft bore 122 is defined by the first shaft end 110 and extends from the first shaft end 110 through the sleeve segment 116 and part of the rotor segment 118. The first shaft bore 122 generally extends through the rotor segment 118 such that an inner end 122a of the first shaft bore 122 is substantially coplanar with the motor end ring 60, which is located near the second shaft end 112. The first shaft bore 122 is separate from the second shaft bore 124 and is discrete. The first shaft bore 122 is fluidically coupled to, or in fluid communication with, a source 160 of fluid F and supplies the first shaft bore 122 with fluid F. In one example, the first shaft bore 122 includes a bar 122b defined downstream of the transverse bore 150.The bar 122b is an increase or decrease in the inner diameter of the first shaft bore 122, which assists the movement of the fluid F through the first shaft bore 122.

[0029] The second shaft bore 124 is defined through the second shaft end 112 and extends from the second shaft end 112 to an inner end 124a, which is defined within the coupling segment 120 adjacent to the rotor segment 118. The second shaft bore 124 defines a plurality of internal threads 158. The internal threads 158 couple to or engage with a mechanical fastening element, such as a clamping bolt, which can be used to couple the shaft speed sensor 40a of the sensor system 28 to the rotor shaft 102.

[0030] The shaft sleeve 104 surrounds the sleeve segment 116 of the rotor shaft 102. The shaft sleeve 104 is made of a metal or metal alloy and is cast, forged, additively manufactured, etc. The shaft sleeve 104 is essentially cylindrical and has a first sleeve end 170 that faces a second sleeve end 172. The shaft sleeve 104 also defines the sleeve lubrication bore 146 and a central shaft bore 176. The central shaft bore 176 extends axially from the first sleeve end 170 to the second sleeve end 172 and is dimensioned such that the shaft sleeve 104 can be connected to the sleeve segment 116. In one example, the shaft sleeve 104 is connected to the sleeve segment 116 by an interference fit or shrink fit.The first sleeve end 170 and the second sleeve end 172 each have a diameter that differs from, and is smaller than, the sleeve diameter of a body 178 of the shaft sleeve 104 defined between the first sleeve end 170 and the second sleeve end 172. Generally, the sleeve diameter D is dimensioned to improve the lateral stiffness of the rotor shaft 102 and is larger than the gear diameter GD associated with the shaft gear 114. In one example, the sleeve diameter D is equal to or smaller than the motor diameter MD associated with the electric motor 50. The lateral stiffness of the rotor shaft 102 is a resistance to deflection or bending of the rotor shaft 102 along its longitudinal axis L.By improving the lateral stiffness of the rotor shaft 102, the shaft sleeve 104 helps to keep the shaft gear 114 in a substantially parallel relationship to the mating gear M of the transmission system 22, thus ensuring efficient torque transmission from the rotor shaft 102 to the transmission system 22. In other words, the improved lateral stiffness keeps a central axis A1 defined by the shaft gear 114 substantially coaxial with the longitudinal axis L, ensuring that the central axis A1 of the shaft gear 114 is substantially parallel to a central axis A2 of the mating gear M of the transmission system 22. For example, the improved lateral stiffness of the rotor shaft 102 reduces the misalignment of the shaft gear 114 and the mating gear M, or the line of misalignment action (MLOA), by a factor of 2 to 3.It should be noted that the sleeve diameter D is merely an example, as the sleeve diameter D can be increased or decreased to give the rotor shaft 102 a predetermined degree of lateral stiffness in order to maintain an substantially parallel relationship between the shaft gear 114 and the mating gear M of the gear system 22.

[0031] The first sleeve end 170 is connected to the rotor shaft 102 such that it lies around and over a portion of the teeth 136 of the shaft gear 114. Thus, in this example, the shaft sleeve 104 overlaps, surrounds, or encloses the recessed area 138 of the sleeve segment 116. The first sleeve end 170 is coupled to the rotor shaft 102 around the teeth 136, so that it does not interfere with the coupling of the teeth 136 to the gear system 22. The second sleeve end 172 is connected to and in contact with the motor end ring 60, which is located near the sleeve segment 116. The second sleeve end 172 also overlaps or surrounds the shoulder 147, which is defined by the difference in diameter between the sleeve segment 116 and the rotor segment 118.In general, the shaft sleeve 104 is held on the rotor sleeve segment by a press fit or shrink fit and is prevented from axial movement by the shaft gear 114 and the adjacent motor end ring 60.

[0032] The sleeve lubrication bore 146 is a transverse bore that runs through the body 178 of the shaft sleeve 104. The sleeve lubrication bore 146 is fluidically coupled to or in fluid communication with the lubrication groove 142. The sleeve lubrication bore 146 receives the fluid F from the lubrication groove 142 and directs the fluid F radially outwards, where the fluid F can flow onto an outer surface of the shaft sleeve 140 and onto the adjacent motor end ring 60.

[0033] The shaft collar 106 helps to hold the electric motor 50 on the rotor shaft 102. In one example, the shaft collar 106 is essentially L-shaped in cross-section. The shaft collar 106 is made of a metal or metal alloy and is cast, stamped, additively manufactured, etc. The shaft collar 106 comprises a first collar end 190, which faces a second collar end 192, and defines a central collar bore 194 extending from the first collar end 190 to the second collar end 192. The first collar end 190 includes a flange 196, which extends radially outward from the first collar end 190. The flange 196 includes a coupling surface 196a, which connects to the motor end ring 60 near the second shaft end 112. In one example, which relates to Fig. As referred to in Figure 4, the shaft collar 106 is connected to the motor end ring 60 by die forging. The flange 196 defines a plurality of recesses 198 at an intersection between the flange 196 and a collar body 202 of the shaft collar 106. The collar body 202 is defined between the first collar end 190 and the second collar end 192. The recesses 198 engage in a groove defined on the motor end ring 60 near the second shaft end 112 to facilitate the coupling of the shaft collar 106 to the electric motor 50. It should be noted that other techniques can be used to connect the shaft collar 106 to the rotor shaft 102.

[0034] The second collar end 192 is located next to the coupling segment 120 when the shaft collar 106 is coupled to the rotor shaft 102. The central collar bore 194 is dimensioned to accommodate the rotor shaft 102 and is coupled to it to rotate with the rotor shaft 102. The shaft collar 106 also defines a plurality of openings 200. The openings 200 are defined through the collar body 202 such that they are spaced apart from each other around a circumference of the collar body 202. The openings 200 are fluidically coupled to or in fluid communication with the feed groove 154 to receive the fluid F from the keyway 148. Fig. 3).

[0035] In relation to Fig. 3. The lubrication system 108 is in fluid communication with, or connected to, the source 160 of fluid F via one or more lines, hydraulic couplings, etc. The source 160 may include a reservoir that supplies the fluid F to the vehicle 10 ( Fig. 1) includes a connected fluid F, such as an oil reservoir, which may contain a pump or similar device to supply the fluid F to the rotor shaft 102. In an example, the lubrication system 108 comprises the first shaft bore 122, the transverse bore 150 defined in the rotor segment 118, the lubrication line 144 defined in the rotor segment 118 and the sleeve segment 116, the lubrication groove 142 defined in the sleeve segment 116, the sleeve lubrication bore 146 defined in the shaft sleeve 104, the feed groove 154 defined in the rotor segment 118, and the openings 200 of the shaft collar 106.

[0036] Generally, the fluid F is supplied from source 160 to the first shaft bore 122. From the first shaft bore 122, the fluid F flows to the transverse bore 150. From the transverse bore 150, the fluid F flows through the keyway 148 to the supply groove 154. From the supply groove 154, the fluid F flows through the openings 200 of the collar to lubricate the bearing connected to the coupling segment 120.

[0037] From the transverse bore 150, the fluid F also flows along the keyway 148 and / or the lubrication line 144 into the portion of the lubrication line 144 defined in the sleeve segment 116. The fluid F flows from the lubrication line 144 into the lubrication groove 142 and from the lubrication groove 142 into the sleeve lubrication bore 146. From the sleeve lubrication bore 146, the fluid F flows over the outer surface of the body 178 and onto the motor end ring 60 near the shaft sleeve 104. By providing the rotor shaft system 100 with the lubrication system 108, the rotor shaft 102 and the electric motor 50 can be lubricated and / or cooled without the need for additional components.

[0038] It should be noted that although the rotor shaft 102 is described here as containing the shaft gear 114 with the recessed area 138, the rotor shaft 102 can also be configured differently to improve its lateral thickness. An example is given with reference to Fig. Figure 6 shows a rotor shaft system 300 which can be coupled to and rotates with the rotor 52. Since the rotor shaft system 300 contains components that are the same or similar to the components of the rotor shaft system 100, which is described in relation to the Fig. As discussed in Sections 1 to 5, the same reference numerals are used to denote the same or similar components. In an example, the rotor shaft system 300 comprises a rotor shaft 302, the shaft sleeve 104, the shaft collar 106, and the lubrication system 108. The rotor shaft 302 is made of a metal or metal alloy and is cast, forged, extruded, additively manufactured, etc. The rotor shaft 302 is essentially cylindrical and extends along the longitudinal axis L. The longitudinal axis L is also an axis of rotation of the rotor shaft 302. The rotor shaft 302 comprises the first shaft end 110 opposite the second shaft end 112, a shaft gear 314, a first segment or sleeve segment 316, the second segment or rotor segment 118, and the third segment or coupling segment 120. The rotor shaft 302 also defines the first shaft bore 122 and the second shaft bore 124.The first shaft end 110 defines the first countersink 130, which is connected to the first shaft bore 122. The first shaft end 110 also includes the chamfer 132. The first shaft end 110 can be coupled to a bearing, e.g., a ball bearing (not shown), which rotatably supports the rotor shaft 302. The second shaft end 112 defines the second countersink 134, which is connected to the second shaft bore 124.

[0039] The shaft gear 314 is defined on the rotor shaft 302, for example, by machining with a lathe. The shaft gear 314 is a pinion with a plurality of teeth 336. In this example, the shaft gear 314 is a helical pinion with a plurality of helical teeth. It should be noted that the shaft gear 314 on the rotor shaft 302 can be shaped such that it engages with the gear system 22 ( Fig. 1) fits together. For example, the shaft gear 314 can be configured as a spur gear with a plurality of spur gear teeth, as a bevel gear with a plurality of bevel gear teeth, etc. In general, the shaft gear 314 is coupled to or engages with the mating gear M of the transmission system 22 to transmit the torque from the drive system 20 to the transmission system 22 ( Fig. 3) The shaft gear 314 can have any number of gear teeth 336 to couple with and drive the gear system 22, and therefore the number of gear teeth 336 shown here is only an example. The shaft gear 314 is arranged on the rotor shaft 302 between the first shaft end 110 and the sleeve segment 316. In one example, the shaft gear 314 has a gear diameter GD, and the gear diameter GD is approximately 41 millimeters (mm) to approximately 42 millimeters (mm).

[0040] The sleeve segment 316 is defined on the rotor shaft 302 directly adjacent to the shaft gear 314. The sleeve segment 316 is defined between the shaft gear 314 and the rotor segment 118. Generally, the shaft sleeve 104 is connected to the rotor shaft 302 such that it is positioned above and connected to the sleeve segment 316. The sleeve segment 316 includes a pivoting area 338, the lubrication groove 142, and part of a lubrication line 144. The pivoting area 338 is defined during the forming of the shaft gear 314. The pivoting area 338 generally includes a shallower-depth toothing (336) that is formed during the forming of the gear shaft 314 on the lathe. A remainder of the sleeve segment 316 has the first diameter D1, which is dimensioned and shaped to connect the shaft sleeve 104 with the rotor shaft 302.The remainder of the sleeve segment 116 extends axially over a distance that allows alignment between the lubrication groove 142 and the sleeve lubrication bore 146. The lubrication groove 142 is connected to and fluidically connected with the sleeve lubrication bore 146 and the lubrication line 144. The lubrication line 144 is coupled to or fluidly connected with the lubrication groove 142 to direct or supply the fluid F to the lubrication groove 142.

[0041] The rotor segment 118 is defined as extending from the sleeve segment 316 to the coupling segment 120. The rotor segment 118 has a second diameter D2, which differs from and is smaller than the first diameter D1 of the sleeve segment 116. The shoulder 147 is defined between the step or change in diameter of the rotor shaft 302 from the sleeve segment 316 to the rotor segment 118. The rotor segment 118 is coupled to the rotor 52 of the electric motor 50. The rotor segment 118 includes the keyway 148 and the transverse bore 150. The key 152 is located in the keyway 148. Fig. Figure 6 shows that the rotor segment 118 is coupled to the rotor 52 so that it is driven by the rotor 52. The shaft sleeve 104 and the shaft collar 106 can also contribute to coupling the rotor shaft 302 to the rotor 52 along the rotor segment 118. The transverse bore 150 is in fluid communication with, or fluidically coupled to, the first shaft bore 122 to receive the fluid F, and the transverse bore 150 is in fluid communication with, or fluidically coupled to, the lubrication line 144 to direct the fluid F into the lubrication line 144. The transverse bore 150 is also in fluid communication with the keyway 148 to direct the fluid F into the keyway 148. In one example, the rotor segment 118 also includes the feed groove 154. The feed groove 154 is in fluid communication with the keyway 148 or is fluidically coupled to it in order to receive the fluid F from the keyway 148.The feed groove 154 supplies the fluid F to the motor end ring 60 near the second shaft end 112 and to the shaft collar 106.

[0042] The coupling segment 120 is defined between the rotor segment 118 and the second shaft end 112. The coupling segment 120 includes the coupling groove 156, which is dimensioned and shaped to support the coupling of the bearing with the rotor shaft 302 in order to support the rotor shaft 302 for rotation.

[0043] The first shaft bore 122 is defined by the first shaft end 110 and extends from the first shaft end 110 through the sleeve segment 316 and part of the rotor segment 118. The first shaft bore 122 is fluidically coupled to, or in fluid communication with, the source 160 of the fluid F and supplies the first shaft bore 122 with the fluid F. In one example, the first shaft bore 122 includes the step or bar 122b, which is defined downstream of the transverse bore 150.

[0044] The second shaft bore 124 is defined by the second shaft end 112 and extends from the second shaft end 112 to the inner end 124a. The second shaft bore 124 defines the internal threads 158, which can be used to couple the shaft speed sensor 40a of the sensor system 28 to the rotor shaft 302.

[0045] The shaft sleeve 104 surrounds the sleeve segment 316 of the rotor shaft 302. The central shaft bore 176 extends axially from the first sleeve end 170 to the second sleeve end 172 and is dimensioned such that the shaft sleeve 104 can be connected to the sleeve segment 316. In one example, the shaft sleeve 104 is connected to the sleeve segment 316 by an interference fit or shrink fit. The first sleeve end 170 and the second sleeve end 172 each have a diameter that differs from and is smaller than the sleeve diameter D of a body 178 of the shaft sleeve 104, which is defined between the first sleeve end 170 and the second sleeve end 172. The sleeve diameter D is dimensioned to improve the lateral stiffness of the rotor shaft 302, and it is larger than the gear diameter GD, which is assigned to the shaft gear 114.In one example, the sleeve diameter D is equal to or smaller than the motor diameter MD associated with the electric motor 50. By improving the lateral stiffness of the rotor shaft 302, the shaft sleeve 104 helps to keep the shaft gear 314 in a substantially parallel relationship to the mating gear M of the gear system 22, thus ensuring efficient torque transmission from the rotor shaft 302 to the gear system 22.

[0046] The first sleeve end 170 is connected to the rotor shaft 302 such that it lies around and over a portion of the teeth 336 of the shaft gear 314. Thus, in this example, the shaft sleeve 104 overlaps, surrounds, or encloses the pivoting area 338 of the sleeve segment 316. The first sleeve end 170 is coupled to the rotor shaft 302 around the teeth 336 to avoid interfering with the coupling of the teeth 336 to the gear system 22 and to facilitate clamping of the electric motor 50 to the rotor shaft 302. The second sleeve end 172 is coupled to and in contact with the motor end ring 60, which is located near the sleeve segment 316. The second sleeve end 172 also overlaps or surrounds the shoulder 147, which is defined by the difference in diameter between the sleeve segment 316 and the rotor segment 118.In general, the shaft sleeve 104 is held on the rotor sleeve segment by a press fit or shrink fit and is prevented from axial movement by the shaft gear 314 and the adjacent motor end ring 60. The sleeve lubrication bore 146 is coupled to or in fluid communication with the lubrication groove 142.

[0047] The shaft collar 106 helps to hold the electric motor 50 on the rotor shaft 302. The shaft collar 106 comprises the first collar end 190, which faces the second collar end 192, and defines the central collar bore 194. The first collar end 190 includes the flange 196, which has the coupling surface 196a that engages with the motor end ring 60 near the second shaft end 112. The shaft collar 106 is forged to the motor end ring 60. The flange 196 defines a plurality of recesses 198 that engage in the groove defined on the motor end ring 60 near the second shaft end 112 to facilitate the coupling of the shaft collar 106 to the electric motor 50. It should be noted that other techniques can be used to connect the shaft collar 106 to the rotor shaft 302.

[0048] The second collar end 192 is located next to the coupling segment 120 when the shaft collar 106 is coupled to the rotor shaft 302. The central collar bore 194 is dimensioned to accommodate the rotor shaft 302 and is coupled to it to rotate with the rotor shaft 302. The shaft collar 106 also defines the plurality of openings 200 that are fluidically coupled to or in fluid communication with the feed groove 154 to receive the fluid F from the keyway 148.

[0049] The lubrication system 108 is in fluid communication with, or connected to, the fluid source 160 F via one or more lines, hydraulic couplings, etc. The lubrication system 108 comprises the first shaft bore 122, the transverse bore 150 defined in the rotor segment 118, the lubrication line 144 defined in the rotor segment 118 and the sleeve segment 316, the lubrication groove 142 defined in the sleeve segment 316, the sleeve lubrication bore 146 defined in the shaft sleeve 104, the feed groove 154 defined in the rotor segment 118, and the openings 200 of the shaft collar 106.

[0050] Generally, the fluid F is supplied from source 160 to the first shaft bore 122. From the first shaft bore 122, the fluid F flows to the transverse bore 150. From the transverse bore 150, the fluid F flows through the keyway 148 to the supply groove 154. From the supply groove 154, the fluid F flows through the openings 200 of the collar to lubricate the bearing connected to the coupling segment 120.

[0051] From the transverse bore 150, the fluid F also flows along the keyway 148 and / or the lubrication line 144 into the section of the lubrication line 144 defined in the sleeve segment 316. The fluid F flows from the lubrication line 144 into the lubrication groove 142 and from the lubrication groove 142 into the sleeve lubrication bore 146. From the sleeve lubrication bore 146, the fluid F flows over the outer surface of the body 178 and onto the motor end ring 60 near the shaft sleeve 104. By providing the rotor shaft system 300 with the lubrication system 108, the rotor shaft 302 and the electric motor 50 can be lubricated and / or cooled without the need for additional components.

[0052] In an example that relates to the Fig. 3 and Fig.Referring to section 6, for the assembly of the rotor shaft system 100, 300 with the electric motor 50, in which the rotor shaft 102, 302 is formed, the first shaft bore 122 and the second shaft bore 124 can be drilled or machined in the rotor shaft 102, 302. The transverse bore 150 can be drilled through the rotor segment 118, and the feed groove 154 can be machined through the rotor segment 118. In the example of the rotor shaft 102, the recessed area 138 is defined in the sleeve segment 116. The lubrication groove 142 and the lubrication line 144 are formed in the rotor shaft 102, 302 by drilling, machining, etc. The keyway 148 is machined to fit the key 152 of the rotor 52. In the example of the rotor shaft 102, the shaft gear 114 is formed near the first shaft end 110, and all deposits are removed from the recessed area 138.In the example of the rotor shaft 302, the shaft gear 314 is formed near the first shaft end 110 and the clearance area 338 is defined during the forming of the shaft gear 314 in the sleeve segment 316.

[0053] When the shaft sleeve 104 is formed, the sleeve lubrication bore 146 is defined by the body 178 of the shaft sleeve 104. The shaft sleeve 104 is pressed or shrunk around the sleeve segment 116, 316. After the stator 54 is connected to the rotor 52 and the motor end rings 60 are connected to the stator 54 and the rotor 52, the rotor 52 is slid onto the keyway 148 of the rotor segment 118 so that the key 152 is received in the keyway 148. The recesses 198 of the shaft collar 106 are aligned with the grooves of the motor end ring 60 near the second shaft end 112, and the shaft collar 106 is coupled to the rotor shaft 102, 302 to secure the rotor 52 and the shaft sleeve 104 on the rotor shaft 102, 302.By coupling the shaft sleeve 104 via a portion of the toothing 136, 336, coupling the rotor 52 to the rotor shaft 102, 302, so that one of the motor end rings 60 engages in the shaft sleeve 104, and clamping the shaft collar 106 to the other of the motor end rings 60 with the shaft collar 106, a clamping path for attaching the electric motor 50 to the rotor shaft 102, 302 runs from the shaft collar 106 through the rotor 52, through the shaft sleeve 104 to the shaft gear 114, 314. Thus, the shaft sleeve 104 is part of the clamping path for coupling the electric motor 50 to the rotor shaft 102, 302.

[0054] When the electric motor 50 is coupled to the rotor shaft 102, 302, the rotor shaft system 100, 300 and the electric motor 50 can be installed in the vehicle 10. The shaft gear 114, 314 can be coupled to the mating gear of the transmission system 22 to transmit the torque from the electric motor 50 to the transmission system 22. The fluid F source 160 can be connected to the rotor shaft 102 via lines, connectors, etc., to supply the lubrication system 108 with fluid F.

[0055] While the drive system 20 supplies energy to the transmission system 22 to drive the vehicle wheels 16 and / or 18 of the vehicle 10, the rotor 52 rotates the rotor shaft 102, 302. The rotation of the rotor shaft 102, 302 drives the transmission system 22 via the mating gear M coupled to the transmission system 22, which is coupled to the shaft gear 114, 314. The source 160 supplies the fluid F to the lubrication system 108, which cools the rotor shaft 102, 302, the shaft sleeve 104, the motor end rings 60, the shaft collar 106, and the bearing coupled to the rotor shaft 102, 302 at the coupling segment 120. The shaft sleeve 104 increases the lateral stiffness of the rotor shaft 102, 302, which reduces the flexibility of the rotor shaft 102, 302 and ensures the alignment between the shaft gear 114, 314 and the mating gear M of the gear system 22.In this respect, the first and second diameters of the rotor shaft 102, 302 are relatively small, and together with the first shaft bore 122 and the second shaft bore 124, the rotor shaft 102, 302 has a relatively low weight. By providing the rotor shaft 102, 302 with reduced diameters D1, D2 and weight, the rotor 52 can drive the rotor shaft 102, 302 at a higher speed and thus, in turn, drive the gear system 22 at a higher speed. The reduced diameter and low weight of the rotor shaft 102, 302 increase its flexibility, while the shaft sleeve 104 increases the lateral stiffness of the rotor shaft 102, 302 without affecting the speed at which the rotor shaft 102, 302 can be driven.This ensures that the shaft gear 114, 314 remains in a substantially parallel relationship to the mating gear M of the gear system 22 during operation, and reduces misalignment of the line of action between the shaft gear 114 and the mating gear M. The shaft sleeve 104 also reduces noise and vibration from the rotor shaft 102, 302 by increasing its stiffness, which in turn reduces the sound transmitted during operation. The considerable uniformity of the diameters D1, D2 of the rotor shaft 102, 302 also reduces manufacturing complexity, and the substantially symmetrical shape of the shaft sleeve 104 further reduces assembly complexity. Since the shaft sleeve 104 is coupled to and surrounds part of the toothing 136, 336, it also acts as part of the shaft gear 114, 314 and is prevented from moving relative to the shaft gear 114, 314.

[0056] Although at least one exemplary embodiment has been presented in the preceding detailed description, it should be recognized that a multitude of variants exist. It should also be recognized that the exemplary embodiment or embodiments are merely examples and are not intended to limit the scope, applicability, or configuration of the disclosure in any way. Rather, the preceding detailed description is intended to provide the person skilled in the art with a practical guide for implementing the exemplary embodiment or embodiments. It is understood that various modifications in the function and arrangement of the elements can be made without departing from the scope of the disclosure as set forth in the appended claims and their statutory equivalents.

Claims

[1] A rotor shaft system for a vehicle, comprising: a rotor shaft having a first shaft end opposite a second shaft end and having a first segment and a second segment defined between the first shaft end and the second shaft end; a shaft gear coupled to the rotor shaft between the first shaft end and the first segment; a shaft sleeve connected to the first segment so as to surround a portion of the shaft gear; and a lubrication system defined at least partially by the rotor shaft and the shaft sleeve, the lubrication system configured to supply fluid to at least a portion of the rotor shaft and the shaft sleeve. [2] The rotor shaft system of claim 1, wherein the rotor shaft has a first shaft bore defined from the first shaft end through the first segment and at least a portion of the second segment, and wherein the first shaft bore is in fluid communication with the lubrication system. [3] The rotor shaft system of claim 2, wherein the lubrication system includes a transverse bore defined by the second segment in fluid communication with the first shaft bore. [4] The rotor shaft system of claim 3, wherein the second segment includes a keyway axially defined on an outer periphery of the second segment, and wherein the transverse bore is in fluid communication with the keyway. [5] The rotor shaft system of claim 4, wherein the keyway is configured to couple the rotor shaft to a rotor associated with an electric motor of the vehicle, wherein a lubrication line is defined by a portion of the first segment and the second segment and is in fluid communication with the keyway, and wherein the shaft sleeve includes a sleeve lubrication bore in fluid communication with the lubrication line. [6] The rotor shaft system of claim 1, wherein the shaft sleeve encloses a recessed area defined in the first segment adjacent the shaft gear. [7] The rotor shaft system of claim 1, wherein the first segment has a first diameter that is greater than a second diameter of the second segment. [8] The rotor shaft system of claim 1, further comprising a shaft collar connected to the second segment proximate the second shaft end. [9] Rotor shaft system according to claim 8, wherein: the second segment contains a feed groove; and the shaft collar has at least one opening which is in fluid communication with the feed groove. [10] Vehicle comprising: an electric motor with a rotor; and the rotor shaft system of claim 1 coupled to the electric motor, wherein the rotor shaft system comprises the second segment coupled to the rotor, the shaft sleeve coupled to the first segment to be disposed between the shaft gear and the rotor, a shaft collar coupled to the second segment between the rotor and the second shaft end, wherein the shaft collar is configured to clamp the rotor and the shaft sleeve to the rotor shaft, and the lubrication system is configured to supply the fluid to at least the portion of the rotor shaft, the shaft sleeve, and the electric motor.

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