Electric drive system

Abstract

Electric drive system, including: an electric motor; a gear set that is rotaryally coupled to the electric motor; a parking brake assembly coupled to the gear set, the parking brake assembly comprising a brake disc and one or more brake pads; and a differential arrangement, wherein the gear set is rotaryally coupled to the differential arrangement via a pinion arrangement, wherein the parking brake arrangement and the electric motor are arranged side by side on the same side of the gear set.

Description

TECHNICAL AREA

[0001] Embodiments of the subject matter disclosed herein relate to electric vehicles and, in particular, to transmission systems for electric vehicles. BACKGROUND AND SUMMARY

[0002] Electric vehicles use electric drive units to generate propulsion power and represent an attractive alternative to vehicles powered solely by internal combustion engines in terms of hydrocarbon emissions. Electric drive units often include transmissions, which comprise a variety of clutches, gears, and shafts to transfer the mechanical power from one or more motors to downstream components such as drive shafts, axles, differentials, and the like. Improving the efficiency and optimizing the functionality of the drive unit enables better performance from vehicles, especially electric and hybrid vehicles that utilize electric drive units.

[0003] Conventional electric transmissions combined with drive shafts often require additional space to integrate the electric motor into the drive axle. Furthermore, the presence of more drive components in the electric drive unit, including the transmission, drive shafts, and drive axles, leads to higher mechanical efficiency losses. Traditionally, parking brakes within an electric powertrain are arranged vertically. For example, a parking brake might be positioned vertically between a transmission and a differential. This necessitates additional space for the drive system.

[0004] The inventors have recognized the aforementioned problems and developed an electric drive system that at least partially solves them. In one example, the electric drive unit comprises an electric motor designed to drive a high-speed reduction gear (HSRU) and a parking brake assembly. The parking brake assembly can be arranged horizontally with respect to the motor and the HSRU. The electric motor drives the HSRU, which then transmits the input power via a gear to the differential assembly. The differential assembly is connected to axle shafts that drive the wheels. Specifically, a first axle shaft drives a first wheel hub, and a second axle shaft drives a second wheel hub. These first and second wheel hubs are coupled to planetary gear assemblies that transmit power to the wheels.

[0005] As previously mentioned, the parking brake assembly can be mounted horizontally on the HSRU and coexist with the engine. The parking brake is designed to hold the gear via a brake disc, which is connected to the HSRU's internal gear via a brake flange. By mounting the parking brake horizontally on the gear, space requirements can be optimized and the overall system footprint reduced, freeing up more space in the vehicle for other components.

[0006] It should be understood that the above brief description is provided to offer a simplified overview of a selection of concepts that are described in more detail in the full description. It is not intended to identify important or essential features of the claimed subject matter, the scope of protection of which is defined solely by the claims following the full description. Furthermore, the claimed subject matter is not limited to implementations that address the disadvantages mentioned above or elsewhere in this disclosure. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 shows a schematic representation of an example vehicle. Fig. Figure 2 shows a schematic representation of a vehicle system. Fig. 3A shows a first example of a conventional drive system. Fig. Figure 3B shows a second example of a conventional drive system. Fig. Figure 4 shows a schematic representation of an electric drive system. Fig. Figure 5 shows a perspective view of an electric drive system. Fig. Figure 6 shows a cross-sectional view of the electric drive system of Fig. 5. Fig. Figure 7 shows schematic representations of operating configurations of a parking brake arrangement of the electric drive system of Fig. 5 and Fig. 6. DETAILED DESCRIPTION

[0007] The following description refers to systems and procedures for an electric drive system of an electric vehicle, comprising an electric motor, a transmission system with a gearbox, a parking brake, a differential, and wheel assemblies. The gearbox may be equipped with a gear set, such as a high-speed reduction gear (HSRU). The parking brake may be mounted horizontally to the HSRU. As described here, the electric motor can power the HSRU, which in turn can power downstream components. These downstream components include the differential and the wheel assemblies. Via the respective axle shafts, the differential can transmit power to the wheel hubs through planetary gear sets. Mounting the parking brake horizontally with the HSRU can reduce the overall compactness of the drive system. An example electric vehicle is described in Fig. Figure 1 shows an exemplary drive system of the electric vehicle. Fig. 2 shown schematically. Examples of conventional powertrains, for both internal combustion engine vehicles and electric vehicles, are shown in the Fig. 3A and Fig. 3B is shown. The illustrations of the electric drive system presented here are in the Fig. Figures 4-6 illustrate example configurations of a parking brake arrangement for the electric drive system presented here. Fig. 7 shown.

[0008] Fig. Figures 1-7 show example configurations with the relative arrangement of the various components. If these elements are in direct contact with each other or directly coupled, they can be described as being in direct contact or directly coupled, respectively, in at least one example. Similarly, elements shown side by side or adjacent to each other can be described as being adjacent to each other or adjacent to each other, respectively, in at least one example. For instance, components that are in planar contact with each other can be described as being in planar contact. As another example, elements that are separated from each other, with only a gap between them and that have no other components, can be described as such in at least one case.In yet another example, elements that are displayed above / below each other, on opposite sides, or to the left / right of each other can be described as such, relative to one another. Furthermore, in at least one example, as shown in the figures, a topmost element or the highest point of an element can be referred to as the "top" of the component, and a bottommost element or the lowest point of the element can be referred to as the "bottom" of the component. The terms top / bottom, upper / lower, and above / below used here can refer to a vertical axis of the figures and be used to describe the positioning of elements within the figures relative to each other. Thus, in one example, elements displayed above other elements are arranged vertically above the other elements.As a further example, the shapes of the elements depicted in the figures can be described as such (e.g., circular, straight, flat, curved, rounded, beveled, angled, etc.). Furthermore, the depicted elements that intersect each other can be described as intersecting elements or as mutually intersecting elements in at least one example. In addition, an element that is depicted inside or outside another element can be described as such.

[0009] Fig. Figure 1 shows a schematic representation of a vehicle system 106 that can obtain drive power from one or more electric motors 154 (e.g., a drive motor). The vehicle system 106 is described here as a forklift truck; however, it should be understood that other vehicle systems are also possible without exceeding the scope of this disclosure. In one embodiment, the electric motors 154 can be traction motors. The electric motors 154 are supplied with electrical energy by a drive battery 158 in order to transmit torque to the rear wheels 157 of the vehicle via the transmission 155. The electric motors 154 can also be operated as generators to provide electrical energy for charging the traction battery 158, for example, during braking. While in Fig. 1 where the electric motors 154 and the transmission system 155 are shown in a rear-wheel drive configuration, other configurations are also possible, such as the use of the electric motor 154 in a front-wheel configuration or in a configuration in which a first output yoke or other interface drives the rear wheels 157 of the vehicle and a second output yoke or other interface drives the front wheels 156 of the vehicle.

[0010] The electric motors 154 and the gearbox 155 can be part of an electric drive system (e.g., an electric drive system). In some examples, the electric motors 154 can be integrated into a gearbox of the gearbox system 155. Additionally or alternatively, the electric motor 154 can be coupled to the outside of a gearbox housing. The gearbox can include at least one clutch and one or more shafts, as described below. The control unit 112 can send a signal to an actuator of the clutch(es) to engage or disengage the clutch(es), thereby coupling or disengaging the power transmission from the electric motor 154 to various shafts and gears within it.

[0011] The control unit 112 can form part of a control system 114. The control system 114 shown receives information from a variety of sensors 116 and sends control signals to a variety of actuators 181. The sensors 116 can include, for example, a battery charge sensor, speed sensors, brake pedal sensors, etc. The actuators can include the clutch(es), friction discs, etc. The control unit 112 can receive input data from the various sensors, process the input data, and trigger the actuators in response to the processed input data based on instructions or codes programmed into it, corresponding to one or more routines. For example, the operator pressing a brake pedal can generate a signal for the brake pedal sensor, which can be forwarded to the control unit 112.Based on the signal received at control unit 112, control unit 112 can trigger brake discs to stop the rotation of the wheel hubs and thus bring the vehicle to a standstill.

[0012] In Fig. Figure 2 shows a schematic representation of a vehicle system 200. In the example shown, the vehicle system 200 is a forklift truck. However, it should be understood that the vehicle system 200 can also assume other configurations without this deviating from the scope of this disclosure. In some examples, the vehicle system 200 can be an example of the one described in Fig. The vehicle system 106 described above is an axle system 299. Fig. 2 and shown in FING. 3A-7 as a reference. An x-axis can be a transverse axis, a y-axis a longitudinal axis, and a z-axis a vertical axis (e.g., parallel to a gravitational axis).

[0013] The vehicle system 200 can comprise a chassis 202 connected to a front drive axle 210 and a rear drive-steer axle 212. The front drive axle 210 can be connected to the front wheels 206 and the rear drive-steer axle 212 to the rear wheels 208. As described above and further explained below, the front drive axle 210 and / or the rear drive-steer axle 212 can be part of a drive system (e.g., a drive unit or drivetrain) of the vehicle system 200 or otherwise coupled to it, the drive system comprising an electric motor, a transmission system (e.g., one or more transmissions), and a differential. In some examples, the drive system can be connected to only one of the two axles, the front drive axle or the rear drive-steer axle.In front-wheel drive configurations, the drive system can be coupled to the front drive axle, and in rear-wheel drive configurations, to the rear drive steering axle. In some examples, a steering wheel 214 can also be integrated into the vehicle system 200. The steering wheel 214 can provide signals to a control system of the drive system to control the wheel angle for steering the vehicle. In some vehicles, the rear axle can be a drive axle and the front axle a steering axle. The parking brake arrangement described here may, in some examples, be used for drive axles rather than steering axles.

[0014] If the vehicle system 200 is a forklift truck, as in Fig. As shown in Figure 2, the vehicle system 200 can also include forks 204. The forks 204 can be configured so that materials can be placed on them, enabling the vehicle to carry and transport the materials.

[0015] Fig. 3A and Fig. Figure 3B shows schematic representations of typical drive systems as they can be installed in a vehicle system, such as vehicle system 106 and / or vehicle system 200. Specifically, it shows Fig. 3A a drive system 300 in a vehicle with an internal combustion engine and Fig. 3B is a drive system 350 in an electric vehicle. Certain components are shared by drive system 300 and drive system 350 and are therefore not listed again for the sake of brevity.

[0016] In the drive system 300, a motor 302 is coupled to a gearbox 304. The power generated by the motor 302 is transmitted to the gearbox 304 and from the gearbox 304 to a differential 316. A parking brake assembly 322 can also be connected to the differential assembly 316. As shown, the parking brake assembly 322 can be arranged longitudinally between the gearbox 304 and the differential 316. The parking brake assembly 322 can comprise a parking brake 306, a parking brake bracket 308, and a parking brake disc 310. For example, the bracket of the parking brake 308 can be attached to a housing of the differential 316, and the parking brake disc 310 can be rotaryally coupled to an output shaft of the gearbox 304.

[0017] In the drive system 350, a battery 352 is coupled to a motor control unit (MCU) 354, which in turn is connected to an electric motor 356. The electric motor 356 is powered by the battery 352 via the MCU 354. The electric motor 356 can be coupled to an electric transmission 358, which in some examples may contain combinations of gears and clutches arranged in gear sets. The power of the electric motor 356 can thus be transmitted to the differential 316 via the transmission 358. Similar to the transmission system 300, in the drive system 350 the parking brake assembly 322 can be coupled longitudinally between the transmission 358 and the differential assembly 316. For example, the bracket of the parking brake 308 can be attached to a housing of the differential 316, and the parking brake disc 310 can be rotaryally coupled to an output shaft of the transmission 358.The longitudinal arrangement of the parking brake assembly between the transmission and the differential can increase the space requirement of the drive system in both internal combustion engine and electric systems.

[0018] In both drive system 300 and drive system 350, the differential 316 can be coupled to the final drives 318 and 320. The axle drive 318 can be rotary-coupled to a first wheel 312, and the axle drive 320 can be rotary-coupled to a second wheel 314. For example, the first wheel 312 can be a right rear wheel and the second wheel 314 a left rear wheel. In another example, the first wheel 312 can be a left front wheel and the second wheel 314 a right front wheel, depending on the type of drive used by the vehicle system.

[0019] As mentioned, in the 300 and 350 drive systems presented here, the parking brake assembly is arranged longitudinally between the transmission and the differential assembly. Applying the parking brake assembly, for example, through friction of the brake pads against the brake disc, can stop the rotation of the differential components and thus also any potential rotation of the wheels and axles. However, if the parking brake assembly is arranged in series between the transmission and the differential assembly, for example, on the transmission output shaft and on a differential housing, the space required for the drivetrain, particularly in the longitudinal direction of the vehicle, can increase.

[0020] Fig. Figure 4 shows a schematic representation of an electric vehicle system 400. The electric drive system 400 can be integrated into a vehicle system, such as the one shown in Fig. 1 vehicle system 106 shown and / or the one in Fig. 2. Vehicle system 200 is shown. The axle system 299 is in turn in Fig. Figure 4 illustrates this. As mentioned previously, the x-axis can be a transverse axis, the y-axis a longitudinal axis, and the z-axis a vertical axis (e.g., parallel to a gravitational axis). In contrast to the combustion engine-powered vehicle drive system 300 described above, the electric powertrains proposed here can offer lower operating costs due to lower electricity costs, reduced maintenance requirements for electric motors compared to combustion engines, higher energy efficiency, and lower operating noise. Furthermore, electric motors, as described here, allow for the provision of maximum torque without requiring a specific rotational speed, as is the case with combustion engines.

[0021] The electric vehicle system 400 can include an MCU 418. The MCU 418 can be coupled to an electric motor 420. The MCU 418 can be configured to power the electric motor 420 from one or more batteries, in some examples by converting direct current (DC) to alternating current (AC) via an inverter. The MCU 418 can also be configured to control the vehicle's speed and acceleration based on various inputs (e.g., throttle inputs).

[0022] The electric motor 420 can be configured to receive power from the MCU 418 and transmit power to one or more transmission components. For example, the electric motor 420 can be configured to transmit power to an HSRU 422 via an input shaft 424 (e.g., a rotor shaft). The HSRU 422 can include a gear set (e.g., an input speed reduction gear) with a first gear 426, a second gear 428, and a third gear 432. The first gear 426 can mesh with the second gear 428, the second gear can mesh with both the first gear 426 and the third gear 432, and the third gear can mesh with the second gear 428. Thus, the second gear 428 can be arranged between the first and third gears 426, 432 along a horizontal axis.

[0023] The input shaft 424 of the electric motor 420 can be rotaryally coupled to the first gear 426, which, as mentioned, can mesh with the second gear 428. The second gear 428 can also be rotaryally coupled to a gear 433. The pinion assembly 433 can comprise a pinion shaft 434 and a bevel gear pair 438. The pinion shaft 434 can be configured to transmit power to a differential assembly 402, for example, via the bevel gear pair 438, which is coupled to a gear of the differential assembly 402. The HSRU 422 can, in some examples, be enclosed by an HSRU housing 436.

[0024] A parking brake assembly 450 can be connected to the HSRU 422. The parking brake assembly 450 can comprise a brake disc 452, one or more brake pads 454, and a parking brake bracket 456. The brake disc can be connected to a parking brake shaft 430. The parking brake assembly 450 can be coupled to the HSRU 422 in a horizontal arrangement. For example, the parking brake assembly 450 can be rotaryally coupled to the third gear 432 of the HSRU 422 via the parking brake shaft 430. In this way, the electric motor 420 and the parking brake assembly 450 can exist side by side in the sense that they are arranged horizontally to each other along the transverse axis. The parking brake assembly 450 can hold the pinion shaft 434 via the brake disc 452.The brake disc 452 can be connected via a brake flange and the third gear 432 of the HSRU 422.

[0025] The differential assembly 402 can be connected to a first axle shaft 440 and a second axle shaft 442. For example, the first axle shaft 440 can be a left axle shaft half and the second axle shaft 442 a right axle shaft half. Each of the first and second axle shafts 440, 442 can be configured to transmit the rotational force to the respective wheel hubs. For example, the first axle shaft 440 can be connected to a first wheel hub 412 via a first planetary gear assembly 404, and the second axle shaft 442 can be connected to a second wheel hub 414 via a second planetary gear assembly 406.

[0026] The first planetary gear assembly 404 can include a sun gear 464, which is rotationally fixed to the first axle shaft 440. Several planet gears 462 mesh with the sun gear 464 and are driven by it. The gears 462 also mesh with a mass source, such as the stationary housing 460. In some examples, the stationary housing 460 can include a locked planet gear. Furthermore, the gears 462 can be supported by a planet carrier 472, which is rotationally coupled to the first wheel hub 412.

[0027] Similarly, the second planetary gear assembly 406 can include a sun gear 470 that is rotationally fixed to the second axle shaft 442. Several planet gears 468 mesh with the sun gear 470 and are driven by it. The gears 468 also mesh with a mass source, e.g., the stationary housing 466. In some examples, the stationary housing 466 can include a locked planetary gear. In some examples, the stationary housing 460 and the stationary housing 466 can also be parts of the same stationary housing. Furthermore, the gears 468 can be supported by a planet carrier 474, which can be rotationally coupled to the second wheel hub 414.

[0028] The first wheel hub 412 can be rotaryally coupled to the first wheel 408, and the second wheel hub 414 can be rotaryly coupled to the second wheel 410. In some examples, the first wheel 408 can be the left wheel of a front wheelset, and the second wheel 410 can be the right wheel of the front wheelset. In another example, the first wheel 408 can be the left wheel of a rear wheelset, and the second wheel 410 can be the right wheel of the rear wheelset.

[0029] Unlike conventional electric drive systems, such as those used in Fig. Figure 3B, in which a parking brake is arranged longitudinally between a transmission system (e.g., one or more gear housings) and a differential, includes a parking brake assembly arranged horizontally next to the electric motor. The parking brake assembly is mounted on the HSRU and connected to the HSRU via a parking brake shaft. The parking brake assembly can coexist horizontally with the electric motor, such that both the parking brake shaft and the input shaft of the electric motor are connected to the HSRU on the same side. Thus, the parking brake assembly and the electric motor can be arranged side by side on the same side of the HSRU.

[0030] When the electric motor 420 is in operation, e.g., when the vehicle is in a driving mode, the torque from the electric motor 420 can be transmitted to the input shaft 424 and to the first gear 426. From the first gear 426, the torque can be transmitted to the second gear 428, with which the first gear 426 is meshed. From the second gear, the torque can be transmitted to the gear 433. In some examples, the pinion shaft of the pinion assembly 433 can thus function as the output shaft for the HSRU 422. From the pinion assembly 433, the torque can be transmitted to the differential assembly 402. From the differential assembly 402, the torque can be transmitted to the first and second axle shafts 440 and 442. The torque can then be transferred from the first and second axle shafts 440, 442 to the first and second planetary arrangement 404, 406.The rotation of the first and second planetary gear sets 404, 406 can cause the first and second planet carriers 472, 474 to rotate, which in turn can cause the first and second gears 408, 410 to rotate, thus driving the vehicle in the desired direction (e.g., forward or backward). The rotation of the second gear 428 can also transmit a rotation to the third gear 432 and thus to the parking brake disc 452. When the parking brake pads 454 are not connected to the parking brake disc 452, the parking brake disc 452 can rotate freely.

[0031] As described below, the parking brake assembly 450 can be activated when the electric motor 420 is not supplying power to the system. When the parking brake assembly 450 is activated by friction between the parking brake pads 454 and the parking brake disc 452, the parking brake disc 452 must not rotate. If the parking brake disc 452 cannot rotate, the downstream components also cannot rotate. For example, the third gear 432 must not rotate, which in turn prevents the second gear 428 from rotating. Therefore, the differential assembly 402, the first and second axle shafts 440, 442, the first and second planetary gear assemblies 404, 406, and the first and second wheel hubs 412, 414 must not rotate. If the first and second wheel hubs 412, 414 cannot rotate, it may be that the first and second wheels 408, 410 are not rotating due to external influences (e.g.(e.g., when rolling down a hill). This allows the vehicle to remain stationary on an inclined surface (e.g., a hill).

[0032] In the Fig. 5 and Fig. Figure 6 shows an electric drive system 500 according to the present disclosure. The electric drive system 500 can be connected to the electric vehicle system 400, which is described in Fig. The electric drive system 500 is described in section 4 and will be similar. Fig. 5 in a perspective exterior view and in Fig. 6 shown in a partial cross-sectional view. Fig. Figure 5 shows a section plane A-A'. The cross-section in Fig. 6 passes through the cutting plane A-A'. The axis system 299 is shown again in the following for illustration. Fig. 5 and Fig. Figure 6 shows the electric drive system 500, as disclosed herein, can be integrated into a vehicle system, such as the vehicle system 106 of Fig. 1 and / or the vehicle system 200 of Fig. 2. The electric drive system 500 described here can be configured for front-wheel drive, where the wheels described are the front wheels of the vehicle. However, it should be understood that the system described here is of course also suitable for rear-wheel drive vehicle systems.

[0033] The electric drive system 500 comprises an electric motor 502 coupled to an HSRU 510. It should be understood that the HSRU described here is an example of a gear set for a transmission system. Other transmission systems with different, more or fewer components were also considered. In some examples, the transmission system described here does not include any gear sets. The use of a simple gear set in the transmission system can further reduce the complexity, the number of components required, and the overall space requirement of the electric drive system.

[0034] The electric drive system 500 also includes a parking brake assembly 521, which is also connected to the HSRU 510. As in the Fig. 5 and Fig. As shown in Figure 6, the parking brake assembly 521 and the electric motor 502 are arranged horizontally side by side and each is coupled to a different gear of the HSRU. For example, the HSRU 510 can be arranged at a first end 590 (e.g., a first longitudinal end) with respect to the parking brake assembly 521 and the electric motor 502, while the parking brake assembly 521 and the electric motor 502 are both arranged at a second end 592 (e.g., a second longitudinal end) with respect to the HSRU 510. The parking brake assembly 521 can be arranged towards a first side 594 (e.g., a first side in the horizontal direction) and the electric motor towards a second side 596 (e.g., a second side in the horizontal direction), thus arranging them horizontally side by side. The first side 594 and the second side 596 can be arranged opposite each other in the horizontal direction.The electric motor 502 can therefore deviate from the longitudinal centerline 598 of the electric drive system 500. By arranging the electric motor and the parking brake assembly side by side, the overall footprint of the electric drive system can be reduced in the longitudinal direction. Furthermore, the number of components can be reduced compared to arranging the parking brake assembly between the transmission and the differential assembly by mounting the parking brake assembly directly on the HSRU housing.

[0035] The HSRU 510 can include a first gear 512, which may be a motor input pinion, a second gear 514, which may be a helical input gear, and a third gear 516, which may be a parking brake gear. In some examples, the HSRU 510 can be enclosed in an HSRU housing 518. An input shaft 503 of the electric motor 502 can be rotaryally coupled to the first gear 512 of the HSRU. For example, the input shaft 503 can be a pinion shaft and the first gear 512 a matching gear. The torque from the electric motor 502 can be transmitted to the HSRU 510 via the input shaft 503.

[0036] The parking brake assembly 521 can comprise a parking brake disc 528, a parking brake actuator 530, parking brake pads 526, a parking brake flange 524, and a parking brake bracket 522. The bracket of the parking brake 522 can be attached to the housing 518 of the HSRU 510. The bracket 522 can be configured to structurally support and stabilize the parking brake assembly 521, thereby maintaining the position of the assembly as mounted on the HSRU housing and reducing any load or stress on the parking brake shaft 520.

[0037] The parking brake pads 526 can comprise a pair of parking brake pads arranged around the parking brake disc 528. The parking brake pads 526 can be configured to engage with the parking brake disc 528 when actuated by the parking brake actuator 530. The parking brake actuator 530 can actuate the parking brake pads 526 to actuate the parking brake disc 528 in response to sensor signals. For example, a driver input, such as parking the vehicle, can transmit a sensor signal indicating that the parking brake should be applied by engaging the parking brake pads 526 with the parking brake disc 528. In some examples, the parking brake actuator 530 can be actuated by a pneumatic system driven by an electric motor or a mechanical motor.

[0038] The parking brake assembly 521 can be connected to the HSRU 510 via a parking brake shaft 520. The parking brake shaft 520 can be rotaryally coupled to the third gear 516 of the HSRU 510. The parking brake flange 524 can connect the parking brake disc 528 to the parking brake shaft 520. The parking brake shaft 520 can be connected to the HSRU 510 on the same side of the HSRU 510 as the input shaft 503 of the electric motor 502.

[0039] The HSRU 510 is also coupled to a differential assembly 508, which is configured to transmit the rotational force to the wheels via drive axles and wheel hubs equipped with planetary gear assemblies. The differential assembly 508 and the drive axles can be housed in a separate casing 550. The HSRU 510 can be coupled to the differential assembly 508 via a pinion. In particular, the second gear 514 of the HSRU 510 can be rotaryally coupled to a pinion shaft 532, which is rigidly coupled to a bevel gear pair 534. The bevel gear pair 534 can be coupled to the differential assembly 508. The differential assembly 508 can, for example, comprise a plurality of gears. The differential assembly 508 can, for example, comprise several gears arranged laterally and end-face. The bevel gear pair 534 can be coupled to one of the several gears of the differential arrangement 508.

[0040] As in Fig. As described in Figure 4, the differential assembly 508 can be rotatably coupled to a first axle shaft 536 and a second axle shaft 538. The first axle shaft 536 and the second axle shaft 538 can be housed in the casing 550. In some examples, the casing 550 can comprise separate housings for the differential assembly 508, the first axle shaft 536, and the second axle shaft 538. In other examples, the casing 550 can be formed from a single piece.

[0041] The first axle shaft 536 can be located on the first side 594 and the second axle shaft 538 can be located on the second side 596. Thus, the first and second axle shafts 536, 538 can be arranged opposite each other in a horizontal direction. The first axle shaft 536 can be coupled to a first gear set and the second axle shaft 538 to a second gear set, which are connected in Fig. 5 or Fig. Figure 6 is not fully shown. The first gear set comprises a first planet carrier 544 and the second gear set a second planet carrier 546.

[0042] A first wheel hub 504 can be engaged with the first gear set, so that a rotation of the first axle shaft 536 results in a rotation of the first wheel hub 504, thereby rotating a first wheel attached to the first wheel hub 504. Likewise, a second wheel hub 506 can be engaged with the second gear set, so that a rotation of the second axle shaft 538 results in a rotation of the second wheel hub 506, thereby rotating a second wheel attached to the second wheel hub 506.

[0043] A first service brake 540 can be mounted on the housing 550 around the first axle shaft 536. In some examples, the first service brake 540 can be connected to the first wheel hub 504 via splined shafts and brake linings. Similarly, a second service brake 542 can be mounted on the housing 550 around the second axle shaft 536. The second service brake 542 can be connected to the second wheel hub 506 via splined shafts and brake discs. During operation of the vehicle system, in which the electric drive system 500 is integrated, the driver's actuation of a brake pedal can cause the friction plates to engage. This engagement of the friction plates can stop the rotation of the corresponding wheel hub and bring the vehicle to a standstill.

[0044] Fig. Figure 7 shows the available configurations of the parking brake assembly 521. In a first configuration 702, shown on the left, the parking brake assembly 521 can be released. In a second configuration 704, shown on the right, the parking brake assembly 521 can be engaged. Fig. Figure 7 schematically shows a part of the electric drive system 500 of the Fig. 5 and Fig. 6, so that common components will not be presented again for the sake of brevity.

[0045] When the parking brake assembly 521 is released, the parking brake pads 526 must not be engaged with the parking brake disc 528. Therefore, when the electric motor 502 supplies rotational force to the drive system 500, the gears of the HSRU 510, including the first gear 512, the second gear 514, and the third gear 516, can rotate. The parking brake shaft 520 and the parking brake disc 528, in turn, can rotate freely. Furthermore, the rotational motion can be transmitted to the differential assembly 508 and delivered as torque to rotate the wheels via the axle shafts.

[0046] When the parking brake assembly 521 is activated, the parking brake pads 526 can engage with the parking brake disc 528. The parking brake assembly 521 can be activated when the parking brake actuator 530 actuates the parking brake pads 526 to activate the parking brake disc 528. The parking brake actuator 530 can actuate the brake pads in response to a sensor signal, for example, from a parking brake input, which can be triggered by the driver engaging a park position. The engagement of the parking brake pads 526 with the parking brake disc 528 described here can involve frictional pressure exerted by the parking brake pads 526 on both sides of the parking brake disc 528. The frictional pressure exerted on the parking brake disc 528 can stop any rotation of the parking brake disc 528.

[0047] Thus, the engagement of the parking brake pads 526 with the parking brake disc 528 stops any rotation of the parking brake disc 528. If the parking brake disc 528 cannot rotate, the parking brake shaft 520, and consequently the third gear 516 and the other gears of the HSRU 510, can no longer rotate either. Further downstream, the first and second axles 536, 538 can no longer rotate, and therefore neither can the wheels connected to the first and second wheel hubs 504, 506. In this way, the vehicle can remain stationary even when on an inclined surface.

[0048] The technical benefit of the electric drive system described here is that it reduces the space required within an electric vehicle. By horizontally arranging a parking brake assembly next to the electric motor, with both coupled to the transmission system (e.g., the HSRU) on the same side, the space required between the transmission system and the differential assembly to which it is coupled can be reduced. Furthermore, a simple transmission system that does not include gear sets can further reduce the system's footprint, resulting in greater space efficiency within the vehicle.

[0049] The following claims highlight in particular certain combinations and subcombinations that are to be considered novel and not obvious. These claims may refer to "one" element or "a first" element, or the equivalent thereof. Such claims are to be understood as including one or more such elements, with two or more such elements neither required nor excluded. Other combinations and subcombinations of the disclosed features, functions, elements, and / or properties may be claimed by amending the present claims or by filing new claims in this or a related application. Such claims, whether they have a broader, narrower, the same, or different scope than the original claims, are also to be considered as included in the subject matter of the present disclosure.

Claims

[1] Electric drive system, comprising: an electric motor; a gear set that is rotaryally coupled to the electric motor; a parking brake assembly coupled to the gear set, the parking brake assembly comprising a brake disc and one or more brake pads; and a differential arrangement, wherein the gear set is rotaryally coupled to the differential arrangement via a pinion arrangement, wherein the parking brake arrangement and the electric motor are arranged side by side on the same side of the gear set. [2] Electric drive system according to claim 1, further comprising a first axle shaft which is rotatably coupled to the differential arrangement on a first side, and a second axle shaft which is rotatably coupled to the differential arrangement on a second side. [3] Electric drive system according to claim 2, wherein the first axle shaft is also rotaryally coupled to a first wheel hub via a first planetary gear arrangement. [4] Electric drive system according to claim 2 or 3, wherein the second axle shaft is also rotaryally coupled to a second wheel hub via a second planetary gear arrangement. [5] Electric drive system according to one of the preceding claims, wherein the pinion arrangement comprises a pinion shaft and a bevel gear pair. [6] Electric drive system according to any of the preceding claims, wherein the gear set is a high-speed reduction unit (HSRU). [7] Electric drive system according to one of the preceding claims, wherein the gear set comprises a first gear rotaryly coupled to an input shaft of the electric motor, a second gear rotaryly coupled to the pinion assembly, and a third gear rotaryly coupled to the parking brake assembly via a parking brake shaft. [8] Electric drive system according to one of the preceding claims, wherein the electric motor is offset relative to a longitudinal centerline of the electric drive system. [9] Electric vehicle system, comprising: an electric motor with an input shaft; a transmission system that is coupled to the electric motor via the input shaft at a first longitudinal end of the transmission system; a parking brake assembly comprising a pair of parking brake linings arranged around a parking brake disc which is rotaryally coupled to a parking brake shaft, wherein the parking brake assembly is coupled to the transmission system via the parking brake shaft at the first longitudinal end of the transmission system; a differential arrangement coupled to the transmission system at a second longitudinal end of the transmission system; and a first and a second wheel hub, which have a first and a second a second drive axle is rotary-coupled with the differential arrangement, wherein the electric motor and the parking brake arrangement are arranged horizontally next to each other at the first longitudinal end of the transmission system. [10] Electric vehicle system according to claim 9, wherein the transmission system comprises an input speed reduction transmission with a motor input pinion, a helical input gear and a parking brake gear.

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