Electric power assisted steering system for a unitary front suspension vehicle

Abstract

An electric power assisted steering (EPAS) system for a unitized beam front suspension vehicle is described. An example EPAS system includes a steering knuckle having a first end and a second end. The first end of the steering knuckle is coupled to a frame of the vehicle. The example EPAS system also includes an EPAS rack assembly having an input shaft, a rack, an electric motor, and an output rod. The rack is coupled to the input shaft and is movable in response to movement of the input shaft. The electric motor is coupled to the rack. The electric motor provides power assist to movement of the rack. The output rod has a first end and a second end. The first end of the output rod is coupled to the rack. The second end of the output rod is coupled to the second end of the steering knuckle.

Description

Technical Field

[0001] This disclosure relates generally to electric power steering (EPAS) systems, and more particularly to EPAS systems for vehicles with solid axle front suspension. Background Technology

[0002] Vehicles such as trucks (e.g., light, medium, heavy, and / or super-heavy trucks), SUVs, and off-road vehicles commonly include solid axle (e.g., solid beam, rigid beam, single beam, etc.) front suspensions for durability reasons. Solid axle front suspensions are traditionally paired with hydraulically operated recirculating ball nut gear systems. These hydraulically operated recirculating ball nut gear systems tend to be bulky and expensive, and typically offer relatively limited performance characteristics. Summary of the Invention

[0003] In some examples, an EPAS system for a solid axle front suspension of a vehicle is disclosed. In some disclosed examples, the EPAS system includes a steering follower arm having a first end and a second end. In some disclosed examples, the first end of the steering follower arm is coupled to the vehicle frame. In some disclosed examples, the EPAS system also includes an EPAS rack assembly. In some disclosed examples, the EPAS rack assembly includes an input shaft, a rack, an electric motor, and an output rod. In some disclosed examples, the rack is coupled to the input shaft and is movable in response to movement of the input shaft. In some disclosed examples, the electric motor is coupled to the rack. In some disclosed examples, the electric motor provides power assistance to the movement of the rack. In some disclosed examples, the output rod has a first end and a second end. In some disclosed examples, the first end of the output rod is coupled to the rack. In some disclosed examples, the second end of the output rod is coupled to the second end of the steering follower arm.

[0004] In some examples, an EPAS system for a solid axle front suspension of a vehicle is disclosed. In some disclosed examples, the EPAS system includes a steering follower arm having a first end and a second end. In some disclosed examples, the first end of the steering follower arm is coupled to the vehicle frame. In some disclosed examples, the EPAS system also includes an EPAS rack assembly mounted to the vehicle frame. In some disclosed examples, the EPAS rack assembly includes an input shaft, a rack, an electric motor, and an output rod. In some disclosed examples, the input shaft is located on the driver's side of the vehicle. In some disclosed examples, the rack is coupled to the input shaft and is movable in response to movement of the input shaft. In some disclosed examples, the electric motor is coupled to the rack. In some disclosed examples, the electric motor provides power assistance to the movement of the rack. In some disclosed examples, the output rod is located on the passenger side of the vehicle. In some disclosed examples, the output rod has a first end and a second end. In some disclosed examples, the first end of the output rod is coupled to the rack. In some publicly available examples, the second end of the output lever is connected to the second end of the steering driven boom. Attached Figure Description

[0005] Figure 1 An example vehicle is shown, which includes an example integral axle front suspension with an EPAS system implemented in accordance with the teachings of this disclosure.

[0006] Figure 2 This is a perspective view of an example integral axle front suspension paired with an example EPAS system constructed according to the teachings of this disclosure.

[0007] Figure 3 yes Figure 2 A top view of an example integral axle front suspension and an example EPAS system.

[0008] Figure 4 yes Figure 2 and Figure 3 A bottom view of an example integral axle front suspension and an example EPAS system.

[0009] Figure 5 This is a sample chassis that is mounted on a vehicle. Figures 2 to 4 Perspective view of an example integral axle front suspension and an example EPAS system.

[0010] Figure 6 yes Figures 2 to 5 Another perspective view of the example integral axle front suspension, example EPAS system, and example chassis.

[0011] Figure 7 Is with Figures 2 to 6 A perspective view of an example dead beam type integral axle front suspension paired with an example EPAS system.

[0012] Certain examples are shown in the accompanying drawings and described in detail below. In describing these examples, similar or identical reference numerals are used to identify the same or similar elements. The figures are not necessarily drawn to scale, and for clarity and / or simplicity, certain features and views may be exaggerated to scale or in illustrated views. Detailed Implementation

[0013] Solid axle front suspensions are very durable and therefore suitable for implementation in vehicles such as trucks (e.g., light, medium, heavy, and / or super trucks), SUVs, and off-road vehicles. However, the hydraulically operated recirculating ball nut gear system traditionally paired with such solid axle front suspensions has several drawbacks. For example, hydraulically operated recirculating ball nut gear systems tend to be bulky and expensive, while also typically offering relatively limited performance characteristics. Hydraulically operated recirculating ball nut gear systems also place a significant compliance burden on the steering system.

[0014] Unlike the known solid axle front suspensions described above, which are paired with hydraulically operated recirculating ball nut gear systems, the solid axle front suspension disclosed herein is advantageously paired with an EPAS system. The disclosed EPAS system offers several positive trade-offs compared to conventional hydraulically operated recirculating ball nut gear systems. For example, the disclosed EPAS system is relatively lighter and less expensive than such hydraulically operated recirculating ball nut gear systems, while also advantageously providing a wider range of performance characteristics, including driver assistance features unavailable via such hydraulically operated recirculating ball nut gear systems. Implementing the disclosed EPAS system instead of such a hydraulically operated recirculating ball nut gear system also advantageously reduces the compliance load associated with the steering system.

[0015] Figure 1 An example vehicle 100 is shown, which includes an example integral axle front suspension 102 with which the EPAS system can be implemented in accordance with the teachings of this disclosure. Figure 1 Vehicle 100 is an over-heavy-duty truck. In other examples, vehicle 100 can be different types of vehicles, such as light, medium, or heavy-duty trucks, SUVs, off-road vehicles, vans, cars, etc. The integral axle front suspension 102 includes an integral axle positioned and / or extending between an example left front wheel 104 and an example right front wheel 106 of vehicle 100. The integral axle can be implemented as a solid beam, rigid beam, single beam, etc., and can be further implemented as a moving beam or a dead beam.

[0016] As used herein, the term "movable beam" refers to an axle or beam that transmits power to one or more wheels of a vehicle. For example, Figure 1 The integral axle of the front suspension 102 can be a moving beam that transmits power to the left front wheel 104 and right front wheel 106 of the vehicle. As used herein, the term "dead beam" refers to an axle or beam that does not transmit power to any of the vehicle's wheels. For example, Figure 1 The integral axle of the front suspension 102 can be a dead beam that does not transmit power to any of the wheels of the vehicle 100, including the left front wheel 104 and the right front wheel 106 of the vehicle 100.

[0017] exist Figure 1 In the illustrated example, vehicle 100 includes an example driver's side 108 located above and / or behind the left front wheel 104 (e.g., on the left side of vehicle 100), and an example passenger's side 110 located above and / or behind the right front wheel 106 (e.g., on the right side of vehicle 100). Vehicle 100 includes an example steering wheel 112 located on the driver's side 108. The steering wheel 112 is coupled to a steering column and one or more steering axes (e.g., a center steering axis, etc.) such that rotational movement of the steering wheel 112 is transmitted to the steering system of vehicle 100 (e.g., an EPAS system). In other examples, the respective orientation and / or position of the driver's side 108 and passenger's side 110 may be different from those of the driver's side 108 and passenger's side 110. Figure 1 The situation is reversed, and the steering wheel 112 can therefore be located on the right side of the vehicle 100.

[0018] Figure 2 This is a perspective view of an example integral axle front suspension 200 paired with an example EPAS system 202 constructed in accordance with the teachings of this disclosure. Figure 3 yes Figure 2 A top view of the example integral axle front suspension 200 and the example EPAS system 202. Figure 4 yes Figure 2 and Figure 3 Bottom view of example integral axle front suspension 200 and example EPAS system 202. Figure 5 This is an example frame 500 that is installed on the vehicle. Figures 2 to 4 Perspective view of example integral axle front suspension 200 and example EPAS system 202. Figure 6 yes Figures 2 to 5 Another perspective view of the example integral axle front suspension 200, the example EPAS system 202, and the example frame 500.

[0019] Figures 2 to 6 The integral axle front suspension 200 and EPAS system 202 can be used as described above. Figure 1The EPAS system 202 is implemented in vehicle 100. The implementation of the EPAS system 202 can be carried out in the absence of and / or exclusion of a circulating ball nut gear system with conventional hydraulic operation, thereby providing the vehicle with the positive trade-offs described above (e.g., reduced weight, reduced cost, improved performance characteristics, reduced steering compliance, etc.).

[0020] exist Figures 2 to 6 In the example shown, the solid axle front suspension 200 includes an example solid axle 204 implemented as a movable beam (e.g., solid beam, rigid beam, single beam, etc.). Figures 2 to 6 The integral axle 204 includes an example first end 206; an example second end 208 located on the opposite side of the first end 206 of the integral axle 204; and an example longitudinal axis 210 extending between the first end 206 and the second end 208 of the integral axle 204. Figures 2 to 6 The first end 206 of the integral axle 204 is connected to an example first steering knuckle 212 (e.g., left steering knuckle) associated with the first front wheel (e.g., left front wheel) of the vehicle. Figures 2 to 6 The second end 208 of the integral axle 204 is connected to an example second steering knuckle 214 (e.g., right steering knuckle) associated with the vehicle's second front wheel (e.g., right front wheel).

[0021] Figures 2 to 6 The EPAS system 202 includes an example EPAS rack assembly 216, an example steering follower 218, an example tie rod 220, an example lateral tie rod 222, and an example steering damper 224. As further described below, Figures 2 to 6 The EPAS rack assembly 216 is coupled to and / or mounted to the vehicle frame 500 such that the EPAS rack assembly 216 is generally oriented along... Figures 2 to 6 The longitudinal axis 210 of the integral axle 204 extends in the direction of its longitudinal axis. Figures 2 to 6 The EPAS rack assembly 216 includes an example rack cover 226, an example input shaft 228, an example rack 230, an example output rod 232, and an example electric motor 234.

[0022] Figures 2 to 6 The rack cover 226 of the EPAS rack assembly 216 is connected to and / or mounted to the vehicle frame 500. Figures 2 to 6 The rack cover 226 accommodates and / or partially accommodates the rack 230 of the EPAS rack assembly 216. Figures 2 to 6 In the example shown, the rack cover 226 includes an example longitudinal axis 236 defined by an example longitudinal axis 238 of the rack 230 and / or the direction of movement. Figure 3 and Figure 4 As shown, Figures 2 to 6The longitudinal axis 236 of the rack cover 226 and / or the longitudinal axis 238 of the rack 230 are relative to Figures 2 to 6 The longitudinal axis 210 of the integral axle 204 is oriented at an example angle 302. Figures 2 to 6 In the example shown, angle 302 has a value of approximately ten degrees (10°). In other examples, the value of angle 302 can be between zero degrees (0°) and thirty degrees (30°).

[0023] Figures 2 to 6 The input shaft 228 of the EPAS rack assembly 216 is rotatable relative to the rack cover 226 of the EPAS rack assembly 216. Figures 2 to 6 The input shaft 228 includes an example first end 240 and a second end located on the opposite side of the first end 240 of the input shaft 228. In some examples, Figures 2 to 6 The first end 240 of the input shaft 228 is connected to the vehicle's intermediate steering shaft. The intermediate steering shaft transmits rotational motion from the steering wheel and / or one or more other steering shafts of the vehicle to... Figures 2 to 6 The input shaft 228 of the EPAS rack assembly 216. In other examples, Figures 2 to 6 The first end 240 of the input shaft 228 is connected to the steering transmission mechanism of the vehicle's steer-by-wire system. The steering transmission mechanism provides rotational motion to the [vehicle] based on one or more signals received at the steering transmission mechanism. Figures 2 to 6 The input shaft 228 of the EPAS rack assembly 216 contains a signal based on steering data detected at the feedback actuator of the steer-by-wire system. In other examples of steer-by-wire systems, this can be cancelled. Figures 2 to 6 The input shaft 228 of the EPAS rack assembly 216. In other examples of this type, movement of the rack 230 of the EPAS rack assembly 216 can be achieved via a ball nut assembly or a concentric motor operatively coupled to an electric motor 234 of the EPAS rack assembly 216. In other examples of this type, the ball nut assembly or the concentric motor operates based on one or more received control signals, wherein the control signals are based on steering data detected at the feedback actuator of the steering-by-wire system.

[0024] exist Figures 2 to 6 In the example shown, the input shaft 228 is located on the driver's side of the vehicle (e.g., Figure 1 (Vehicle 100, driver's side 108). Figures 2 to 6 The second end of the input shaft 228 includes and / or is operatively coupled to a pinion located within a rack cover 226 of the EPAS rack assembly 216. In some examples, the pinion may be integrally formed with and / or integrally formed at the second end of the input shaft 228. The pinion engages, meshes with, and / or drives the rack 230 of the EPAS rack assembly 216. Figures 2 to 6The rack 230 of the EPAS rack assembly 216 is slidable relative to the rack cover 226 of the EPAS rack assembly 216. The input shaft 228, pinion and rack 230 of the EPAS rack assembly 216 are operatively coupled such that the pinion moves (e.g., rotates) in response to movement (e.g., rotation) of the input shaft 228, and the rack 230 moves (e.g., translates and / or slides) in response to movement (e.g., rotation) of the pinion.

[0025] Figures 2 to 6 The output rod 232 of the EPAS rack assembly 216 includes an example first end 402 and an example second end 404 located on the opposite side of the first end 402 of the output rod 232. Figures 2 to 6 The first end 402 of the output rod 232 is connected (e.g., rigidly and non-rotatably connected) to the rack 230 of the EPAS rack assembly 216, such that the output rod 232 moves (e.g., translates and / or slides) with the rack 230. In some examples, Figures 2 to 6 The output rod 232 of the EPAS rack assembly 216 (e.g., the first end 402 of the output rod 232) can be integrally formed with the rack 230 of the EPAS rack assembly 216. As further described below, Figures 2 to 6 The second end 404 of the output rod 232 is connected to Figures 2 to 6 The steering is driven by boom 218. Figures 2 to 6 In the example shown, the output lever 232 and the steering follower 218 are located on the passenger side of the vehicle (e.g., Figure 1 The passenger side 110 of the vehicle 100. The rack 230, the output rod 232 and the steering follower 218 are operatively connected such that the output rod 232 moves (e.g., translates and / or slides) in response to movement of the rack 230, and the steering follower 218 moves (e.g., pivots and / or rotates) in response to movement of the output rod 232.

[0026] Figures 2 to 6 The electric motor 234 of the EPAS rack assembly 216 provides power assistance to the movement of the rack 230 of the EPAS rack assembly 216. In some examples, the level and / or degree of power assistance provided by the electric motor 234 can be controlled and / or adjusted via a controller of the EPAS system 202. In some examples, it can be based on data obtained from the vehicle's steering wheel, steering column, and / or steering shaft (e.g., center steering shaft), and / or from... Figures 2 to 6 The level and / or degree of power assistance provided by the electric motor 234 is determined by the steering input obtained from the input shaft 228 of the EPAS rack assembly 216. In other examples, it may be based on the feedback actuator and / or steering transmission mechanism, ball nut assembly, or concentric motor of the vehicle's steer-by-wire system, and / or from... Figures 2 to 6 The steering input obtained from the input shaft 228 of the EPAS rack assembly 216 determines the level and / or degree of power assistance provided by the electric motor 234.

[0027] Figures 2 to 6 The electric motor 234 of the EPAS rack assembly 216 includes an example motor housing 242 and an example drive shaft 244. Figures 2 to 6 The motor housing 242 of the electric motor 234 is coupled to and / or mounted to the vehicle frame 500 and / or the rack housing 226 of the EPAS rack assembly 216. The motor housing 242 accommodates and / or partially accommodates one or more operating and / or movable components of the electric motor 234. For example, the drive shaft 244 of the electric motor 234 is defined by the drive shaft of the electric motor 234, wherein the drive shaft is accommodated and / or partially housed within the motor housing 242 of the electric motor 234. The drive shaft of the electric motor 234 moves (e.g., rotates) in response to current supplied to and / or generated at the electric motor 234. Figures 2 to 6 In the example shown, Figures 2 to 6 The drive shaft 244 of the electric motor 234 is parallel to Figures 2 to 6 The longitudinal axis 236 of the rack cover 226, and / or parallel to Figures 2 to 6 The longitudinal axis 238 of the rack 230.

[0028] Figures 2 to 6 An electric motor 234 of the EPAS rack assembly 216 is operatively coupled to a rack 230 of the EPAS rack assembly 216. For example, the drive shaft of the electric motor 234 may be coupled to the rack 230 via a gear train, such that movement of the drive shaft is transmitted to the rack via the gear train. In some examples, the gear train may be received and / or partially housed within a rack cover 226 and / or a motor cover 242. The rack 230, gear train, and electric motor 234 of the EPAS rack assembly 216 are operatively coupled such that the gear train moves (e.g., rotates) in response to movement (e.g., rotation) of the drive shaft of the electric motor 234, and the rack 230 moves (e.g., translates and / or slides) in response to movement (e.g., rotation) of the gear train.

[0029] Figures 2 to 6 The steering follower 218 of the EPAS system 202 includes an example first end 246 and an example second end 248 located on the opposite side of the first end 246 of the steering follower 218. Figures 2 to 6 The steering is connected from the first end 246 of the boom 218 to the vehicle frame 500. Figures 2 to 6 The steering is connected from the second end 248 of the boom 218 to Figures 2 to 6The second end 404 of the output rod 232 of the EPAS rack assembly 216. As further described below, the second end 248 of the steering follower 218 is also connected to Figures 2 to 6 The pull rod 220. The output rod 232, the steering follower arm 218 and the pull rod 220 are operably connected such that the steering follower arm 218 moves (e.g., pivots and / or rotates) in response to movement (e.g., translation and / or sliding) of the output rod 232, and the pull rod 220 moves (e.g., pivots) in response to movement (e.g., pivoting and / or rotating) of the steering follower arm 218.

[0030] Figures 2 to 6 The EPAS system 202 includes a first example end 250 and a second example end 252 located on the opposite side of the first end 250 of the EPAS system 202. Figures 2 to 6 The first end 250 of the straight pull rod 220 is connected to Figures 2 to 6 The steering is initiated from the second end 248 of the boom 218. Figures 2 to 6 The second end 252 of the tie rod 220 is connected to the first steering knuckle 212 of the vehicle (e.g., the left steering knuckle). The steering follower arm 218, the tie rod 220 and the first steering knuckle 212 are operatively connected such that the tie rod 220 moves (e.g., pivots) in response to movement (e.g., pivoting and / or rotation) of the steering follower arm 218, and the first steering knuckle 212 moves (e.g., pivots) in response to movement (e.g., pivoting) of the tie rod 220.

[0031] Figures 2 to 6 The EPAS system 202's tie rod 222 includes an example first end 254 and an example second end 256 located on the opposite side of the first end 254 of the tie rod 222. Figures 2 to 6 The first end 254 of the tie rod 222 is connected to the first steering knuckle 212 of the vehicle (e.g., the left steering knuckle). Figures 2 to 6 The second end 256 of the tie rod 222 is connected to the second steering knuckle 214 of the vehicle (e.g., the right steering knuckle). The first steering knuckle 212, the tie rod 222, and the second steering knuckle 214 are operatively connected such that the tie rod 222 moves (e.g., pivots) in response to movement of the first steering knuckle 212 (e.g., a movement that may occur in response to movement of the tie rod 220), and the second steering knuckle 214 moves (e.g., pivots) in response to movement of the tie rod 222 (e.g., a movement).

[0032] Figures 2 to 6 EPAS system 202 steering damper 224 pairs Figures 2 to 6 The steering is damped by one or more of the aforementioned movements of the boom 218, the tie rod 220, and / or the lateral tie rod 222. Figures 2 to 6The steering damper 224 includes an example cylinder 258 and an example piston 260, the example piston 260 being movable (e.g., sliding) within and / or relative to the cylinder 258. Figures 2 to 6 In the illustrated example, the example first end 262 of the steering damper 224, formed by and / or coupled to the cylinder 258 of the steering damper 224, is coupled to... Figures 2 to 6 The rack cover 226, and the example second end 264 of the steering damper 224 formed by and / or coupled to the piston 260 of the steering damper 224 is coupled to... Figures 2 to 6 The steering follower arm 218. In some examples, the first end 262 of the steering damper 224 may alternatively be coupled to the vehicle frame 500. In some examples, the second end 264 of the steering damper 224 may alternatively be coupled to the tie rod 220 or the lateral tie rod 222.

[0033] therefore, Figures 2 to 6 The input shaft 228 moves (e.g., rotates) in response to movement (e.g., rotation) of the vehicle's intermediate steering shaft (or, in the case of a steering-by-wire implementation, in response to movement of the steering transmission mechanism, ball nut assembly, or concentric motor). Figures 2 to 6 The rack 230 moves in response to the movement of the input shaft 228 (e.g., translation and / or sliding). Figures 2 to 6 The output rod 232 moves (e.g., translates and / or slides) in response to the movement of the rack 230. Figures 2 to 6 The steering follower 218 moves (pivots and / or rotates) in response to the movement of the output lever 232. Figures 2 to 6 The tie rod 220 moves in response to movement of the steering follower 218 (e.g., pivoting). Figures 2 to 6 The first steering knuckle 212 moves (e.g., pivots) in response to the movement of the tie rod 220. Figures 2 to 6 The tie rod 222 moves (e.g., pivots) in response to the movement of the first steering knuckle 212, and Figures 2 to 6 The second steering knuckle 214 moves (e.g., pivots) in response to the movement of the tie rod 222. Figures 2 to 6 The integral axle 204 extends between the first steering knuckle 212 and the second steering knuckle 214. Figures 2 to 6 The electric motor 234 provides power assistance for the movement of the rack 230 described above. Figures 2 to 6 The steering damper 224 dampens one or more of the aforementioned movements of the steering follower 218, the tie rod 220, and / or the lateral tie rod 222.

[0034] Figure 7 Is with Figures 2 to 6A perspective view of the example dead beam type integral axle front suspension 700 paired with the example EPAS system 202. Figure 7 The integral axle front suspension 700 and EPAS system 202 can be used in vehicles as described above. Figure 1 The EPAS system 202 is implemented in vehicle 100. The implementation of the EPAS system 202 can be carried out in the absence of and / or exclusion of a circulating ball nut gear system with conventional hydraulic operation, thereby providing the vehicle with the positive trade-offs described above (e.g., reduced weight, reduced cost, improved performance characteristics, reduced steering compliance, etc.).

[0035] exist Figure 7 In the example shown, the dead beam type solid axle front suspension 700 includes an example solid axle 704 implemented as a dead beam (e.g., solid beam, rigid beam, single beam, etc.). Figure 7 The integral axle 704 includes an example first end 706; an example second end 708 located on the opposite side of the first end 706 of the integral axle 704; and an example longitudinal axis 710 extending between the first end 706 and the second end 708 of the integral axle 704. Figure 7 The first end 706 of the integral axle 704 is connected to an example first steering knuckle 712 (e.g., left steering knuckle) associated with the first front wheel (e.g., left front wheel) of the vehicle. Figure 7 The second end 708 of the integral axle 704 is connected to an example second steering knuckle 714 (e.g., right steering knuckle) associated with the vehicle's second front wheel (e.g., right front wheel).

[0036] Figure 7 The first end 706, the second end 708, and the longitudinal axis 710 of the integral axle 704 correspond to the description above. Figures 2 to 6 The integral axle 204 has a first end 206, a second end 208, and a longitudinal axis 210. Figure 7 The first steering knuckle 712 and the second steering knuckle 714 correspond to the descriptions above. Figures 2 to 6 The first steering knuckle 212 and the second steering knuckle 214. Figures 2 to 6 The EPAS system 202 is combined with the above. Figure 2 The active beam type integral axle front suspension 200 is basically the same as described above. Figure 7 The dead beam type integral axle front suspension 700 is implemented together with and / or paired with it.

[0037] Based on the foregoing, it will be understood that the disclosed EPAS system for vehicles with solid axle front suspension offers numerous advantages over conventional hydraulically operated recirculating ball nut gear systems for solid axle front suspension vehicles. For example, compared to such hydraulically operated recirculating ball nut gear systems, the disclosed EPAS system is relatively lighter and less expensive, while also advantageously providing a wider range of performance characteristics, including driver assistance features unavailable via such hydraulically operated recirculating ball nut gear systems. Implementing the disclosed EPAS system instead of such hydraulically operated recirculating ball nut gear systems also advantageously reduces the compliance load associated with the steering system.

[0038] In some examples, an EPAS system for a solid axle front suspension of a vehicle is disclosed. In some disclosed examples, the EPAS system includes a steering follower arm having a first end and a second end. In some disclosed examples, the first end of the steering follower arm is coupled to the vehicle frame. In some disclosed examples, the EPAS system also includes an EPAS rack assembly. In some disclosed examples, the EPAS rack assembly includes an input shaft, a rack, an electric motor, and an output rod. In some disclosed examples, the rack is coupled to the input shaft and is movable in response to movement of the input shaft. In some disclosed examples, the electric motor is coupled to the rack. In some disclosed examples, the electric motor provides power assistance to the movement of the rack. In some disclosed examples, the output rod has a first end and a second end. In some disclosed examples, the first end of the output rod is coupled to the rack. In some disclosed examples, the second end of the output rod is coupled to the second end of the steering follower arm.

[0039] In some disclosed examples, the EPAS rack assembly is mounted to the vehicle frame. In some disclosed examples, the rack has a longitudinal axis oriented at an angle between 0 and 30 degrees relative to the longitudinal axis of the solid axle of the front suspension. In some disclosed examples, the electric motor has a drive axis parallel to the longitudinal axis of the rack.

[0040] In some disclosed examples, the input shaft is coupled to an intermediate steering shaft. In some disclosed examples, the input shaft is movable in response to movement of the intermediate steering shaft. In some disclosed examples, the EPAS rack assembly also includes a rack cover. In some disclosed examples, the rack is slidable relative to the rack cover. In some disclosed examples, the input shaft is rotatable relative to the rack cover. In some disclosed examples, the input shaft is operatively coupled to a pinion located within the rack cover. In some disclosed examples, the pinion is movable in response to movement of the input shaft, and the rack is movable in response to movement of the pinion.

[0041] In some disclosed examples, the EPAS system also includes a tie rod having a first end and a second end. In some disclosed examples, the first end of the tie rod is coupled to the second end of the steering follower. In some disclosed examples, the second end of the tie rod is coupled to the vehicle's first steering knuckle.

[0042] In some disclosed examples, the EPAS system also includes a tie rod having a first end and a second end. In some disclosed examples, the first end of the tie rod is coupled to a first steering knuckle. In some disclosed examples, the second end of the tie rod is coupled to a second steering knuckle of the vehicle.

[0043] In some disclosed examples, the EPAS system also includes a steering damper having a first end and a second end. In some disclosed examples, the first end of the steering damper is coupled to either the vehicle frame or the rack cover of the EPAS rack assembly. In some disclosed examples, the second end of the steering damper is coupled to either the steering follower, tie rod, or lateral tie rod.

[0044] In some publicly available examples, the output lever can move in response to the movement of the rack, the steering follower can move in response to the movement of the output lever, the tie rod can move in response to the movement of the steering follower, the first steering knuckle can move in response to the movement of the tie rod, the lateral tie rod can move in response to the movement of the first steering knuckle, and the second steering knuckle can move in response to the movement of the lateral tie rod.

[0045] In some published examples, the solid axle of the front suspension extends between the vehicle's first and second steering knuckles. In other published examples, the solid axle is either a moving beam or a dead beam.

[0046] In some examples, an EPAS system for a solid axle front suspension of a vehicle is disclosed. In some disclosed examples, the EPAS system includes a steering follower arm having a first end and a second end. In some disclosed examples, the first end of the steering follower arm is coupled to the vehicle frame. In some disclosed examples, the EPAS system also includes an EPAS rack assembly mounted to the vehicle frame. In some disclosed examples, the EPAS rack assembly includes an input shaft, a rack, an electric motor, and an output rod. In some disclosed examples, the input shaft is located on the driver's side of the vehicle. In some disclosed examples, the rack is coupled to the input shaft and is movable in response to movement of the input shaft. In some disclosed examples, the electric motor is coupled to the rack. In some disclosed examples, the electric motor provides power assistance to the movement of the rack. In some disclosed examples, the output rod is located on the passenger side of the vehicle. In some disclosed examples, the output rod has a first end and a second end. In some disclosed examples, the first end of the output rod is coupled to the rack. In some publicly available examples, the second end of the output lever is connected to the second end of the steering driven boom.

[0047] In some publicly available examples, the rack has a longitudinal axis that is oriented at an angle between 0 and 30 degrees relative to the longitudinal axis of the integral axle of the front suspension of the integral axle.

[0048] In some disclosed examples, the EPAS system also includes a tie rod having a first end and a second end. In some disclosed examples, the first end of the tie rod is coupled to the second end of the steering follower. In some disclosed examples, the second end of the tie rod is coupled to the vehicle's first steering knuckle.

[0049] In some disclosed examples, the EPAS system also includes a tie rod having a first end and a second end. In some disclosed examples, the first end of the tie rod is coupled to a first steering knuckle. In some disclosed examples, the second end of the tie rod is coupled to a second steering knuckle of the vehicle.

[0050] In some disclosed examples, the EPAS system also includes a steering damper having a first end and a second end. In some disclosed examples, the first end of the steering damper is coupled to either the vehicle frame or the rack cover of the EPAS rack assembly. In some disclosed examples, the second end of the steering damper is coupled to either the steering follower, tie rod, or lateral tie rod.

[0051] In some publicly available examples, the output lever can move in response to the movement of the rack, the steering follower can move in response to the movement of the output lever, the tie rod can move in response to the movement of the steering follower, the first steering knuckle can move in response to the movement of the tie rod, the lateral tie rod can move in response to the movement of the first steering knuckle, and the second steering knuckle can move in response to the movement of the lateral tie rod.

[0052] In some published examples, the solid axle of the front suspension extends between the vehicle's first and second steering knuckles. In other published examples, the solid axle is either a moving beam or a dead beam.

[0053] Although certain example devices and articles of manufacture have been disclosed herein, the scope of this patent is not limited thereto. Rather, this patent covers all devices and articles of manufacture that actually fall within the scope of the claims of this patent.

[0054] According to one embodiment, a further feature of the above invention is that: a tie rod having a first end and a second end, the first end of the tie rod being connected to the second end of the steering driven arm, and the second end of the tie rod being connected to the first steering knuckle of the vehicle.

[0055] According to one embodiment, a further feature of the above invention is that: a tie rod having a first end and a second end, the first end of the tie rod being connected to a first steering knuckle, and the second end of the tie rod being connected to a second steering knuckle of the vehicle.

[0056] According to one embodiment, a further feature of the above invention is: a steering damper having a first end and a second end, the first end of the steering damper being connected to one of the vehicle frame or the rack cover of the EPAS rack assembly, and the second end of the steering damper being connected to one of the steering follower, tie rod, or lateral tie rod.

[0057] According to one embodiment, the output lever is movable in response to the movement of the rack, the steering follower is movable in response to the movement of the output lever, the tie rod is movable in response to the movement of the steering follower, the first steering knuckle is movable in response to the movement of the tie rod, the lateral tie rod is movable in response to the movement of the first steering knuckle, and the second steering knuckle is movable in response to the movement of the lateral tie rod.

[0058] According to one embodiment, the integral axle of the front suspension extends between the first and second steering knuckles of the vehicle, and the integral axle is either a moving beam or a dead beam.

Claims

1. An electric power steering (EPAS) system for a solid axle front suspension of a vehicle, the EPAS system comprising: A steering follower arm having a first end and a second end, the first end of the steering follower arm being connected to the vehicle frame; as well as EPAS rack assembly, the EPAS rack assembly comprising: Input axis; A rack, connected to the input shaft, the rack being movable in response to movement of the input shaft; An electric motor, connected to the rack, provides power assistance for the movement of the rack; and An output rod having a first end and a second end, the first end of the output rod being connected to the rack, and the second end of the output rod being connected to the second end of the steering driven arm.

2. The EPAS system of claim 1, wherein the EPAS rack assembly is mounted to the vehicle frame.

3. The EPAS system of claim 1, wherein the rack has a longitudinal axis oriented at an angle between 0 and 30 degrees relative to the longitudinal axis of the integral axle of the integral axle front suspension.

4. The EPAS system of claim 3, wherein the electric motor has a drive axis parallel to the longitudinal axis of the rack.

5. The EPAS system of any one of claims 1 to 4, wherein the input shaft is coupled to an intermediate steering shaft, the input shaft being movable in response to movement of the intermediate steering shaft.

6. The EPAS system of any one of claims 1 to 4, wherein the EPAS rack assembly further comprises a rack cover, the rack being slidable relative to the rack cover, and the input shaft being rotatable relative to the rack cover.

7. The EPAS system of claim 6, wherein the input shaft is operatively coupled to a pinion located within the rack housing, the pinion being movable in response to movement of the input shaft, and the rack being movable in response to movement of the pinion.

8. The EPAS system of any one of claims 1 to 4, the EPAS system further comprising a tie rod having a first end and a second end, the first end of the tie rod being coupled to the second end of the steering follower arm, and the second end of the tie rod being coupled to a first steering knuckle of the vehicle.

9. The EPAS system of claim 8, further comprising a tie rod having a first end and a second end, the first end of the tie rod being coupled to a first steering knuckle, and the second end of the tie rod being coupled to a second steering knuckle of the vehicle.

10. The EPAS system of claim 9, further comprising a steering damper having a first end and a second end, the first end of the steering damper being coupled to one of the vehicle frame or the rack cover of the EPAS rack assembly, and the second end of the steering damper being coupled to one of the steering follower, the tie rod, or the lateral tie rod.

11. The EPAS system of claim 9, wherein the output lever is movable in response to movement of the rack, the steering follower is movable in response to movement of the output lever, the tie rod is movable in response to movement of the steering follower, the first steering knuckle is movable in response to movement of the tie rod, the lateral tie rod is movable in response to movement of the first steering knuckle, and the second steering knuckle is movable in response to movement of the lateral tie rod.

12. The EPAS system of claim 9, wherein the integral axle of the integral axle front suspension extends between the first steering knuckle and the second steering knuckle of the vehicle.

13. The EPAS system of claim 12, wherein the integral axle is either a movable beam or a fixed beam.

14. An electric power steering (EPAS) system for a solid axle front suspension of a vehicle, the EPAS system comprising: A steering follower arm having a first end and a second end, the first end of the steering follower arm being connected to the vehicle frame; as well as An EPAS rack assembly, the EPAS rack assembly being mounted to the vehicle frame, the EPAS rack assembly comprising: An input shaft located on the driver's side of the vehicle; A rack, connected to the input shaft, the rack being movable in response to movement of the input shaft; An electric motor, connected to the rack, provides power assistance for the movement of the rack; and An output lever, located on the passenger side of the vehicle, having a first end and a second end, the first end of the output lever being connected to the rack, and the second end of the output lever being connected to the second end of the steering follower.

15. The EPAS system of claim 14, wherein the rack has a longitudinal axis oriented at an angle between 0 and 30 degrees relative to the longitudinal axis of the integral axle of the integral axle front suspension.

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