A parallel steering system

Abstract

This invention relates to the field of vehicle steering system technology, specifically to a parallel steering system, comprising: a transmission assembly including an input shaft and a lead screw unit; the lead screw unit including a lead screw, a lead screw nut, a sector gear, and an output shaft; the lead screw and input shaft are coaxially connected; the lead screw nut is conventionally sleeved on the lead screw; the lead screw nut has transmission teeth on the side facing the sector gear, and the sector gear matches the transmission teeth; the lead screw nut can move along the extension direction of the lead screw to drive the sector gear to oscillate; the output shaft is coaxially arranged with the sector gear; a power assist assembly including a driver and a drive gear set; the drive gear set including a first gear and a second gear; the first gear is connected to the driver, and the second gear is connected to the lead screw, with the first gear and second gear being connected in a driving connection; the transmission assembly is disposed in a first cavity, and the power assist assembly is disposed in a second cavity; the axes of the lead screw and driver are arranged parallel to each other. This solves the problem of existing steering systems occupying too much lateral space.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of vehicle steering systems, in particular to a parallel steering system. BACKGROUND

[0002] Commercial vehicles are automobiles designed and technically characterized for transporting people and goods. Common commercial vehicle models include pickup trucks, minivans, light trucks, minivans, dump trucks, cargo trucks, tractors, trailers, etc. When these vehicles are in operation, due to their large self-weight and load, the steering control force required during steering is large, making it difficult for the driver to operate. Therefore, in order to improve the steering performance and reduce the steering force exerted by the driver, a steering device with a power-assisted function is often used in the steering system.

[0003] The existing steering system usually uses a worm gear structure to transmit the torque force of the electric motor to the driving structure of the steering, but such a structure also requires the worm in the worm gear and the electric motor to be perpendicular to the driving shaft structure, resulting in a large horizontal space occupied by the entire product structure. However, the horizontal space of the vehicle body for installing the power-assisted structure is limited, especially as the demand for vehicle intelligence and electrification increases, there are more space requirements for other components in this area. Therefore, the existing steering system structure cannot meet the increasing space requirements, and a new power-assisted steering device is needed. SUMMARY

[0004] To solve the problem of the existing steering system occupying more horizontal space, the present application provides a parallel steering system, which comprises a housing, a transmission assembly and a power-assisted assembly. The housing comprises a first cavity and a second cavity extending in the same direction. The transmission assembly comprises an input shaft and a lead screw unit, the lead screw unit comprising a lead screw, a nut, a sector gear and an output shaft. The lead screw is coaxially connected with the input shaft, the nut is sleeved on the lead screw, the side of the nut facing the sector gear is provided with a transmission tooth, the sector gear is matched with the transmission tooth, the nut can move along the extension direction of the lead screw to drive the sector gear to swing, and the output shaft is coaxially arranged with the sector gear. The power-assisted assembly comprises a driver and a drive gear set, the drive gear set comprises a first gear and a second gear, the first gear is connected with the driver, the second gear is connected with the lead screw, and the first gear is in transmission connection with the second gear. The transmission assembly is arranged in the first cavity, the power-assisted assembly is arranged in the second cavity, and the axis of the lead screw and the driver is arranged in parallel.

[0005] In some embodiments, the sector gear is arranged on the first side of the lead screw, the first gear is arranged on the second side of the lead screw, and the first side and the second side are arranged opposite to each other. The included angle between the sector gear and the first gear is 150° to 180°.

[0006] In some embodiments, the first cavity comprises a first support wall and a second support wall away from the input shaft, the input shaft penetrating through the first support wall and extending into the first cavity, the input shaft being supported by the first support wall, and one end of the lead screw being supported by the second support wall; the thickness of the second support wall is greater than the thickness of the first support wall.

[0007] In some embodiments, the power-assisted assembly further comprises a speed reducer, the speed reducer being disposed between the driver and the first gear, the speed reducer being in driving connection with the driver and the first gear respectively, and the speed reducer being disposed in the second cavity.

[0008] In some embodiments, the second cavity comprises a third support wall and a fourth support wall, the third support wall being used for supporting and fixing the driver, and the first gear being rotatably connected to the third support wall and the fourth support wall through the rotating shaft.

[0009] In some embodiments, the speed reducer is a cycloidal pin wheel speed reducer.

[0010] In some embodiments, the first support wall and the second support wall are connected by a first wall body to form the first cavity, the driver comprises a driver housing, and the first wall body and the driver housing are connected by a reinforcing wall.

[0011] In some embodiments, the nut comprises a nut seat, the nut seat being provided with a ball returning device, and the nut seat and the lead screw are provided with a ball therebetween, the ball being capable of rolling along a track formed by the nut seat, the lead screw and the ball returning device.

[0012] In some embodiments, the parallel steering system further comprises a control assembly and a rotation sensor, the rotation sensor being disposed at the input shaft and being capable of detecting the rotation condition of the input shaft, and the control assembly being in communication connection with the rotation sensor and the driver, and the control assembly being capable of controlling the operation of the driver according to the rotation condition of the input shaft.

[0013] In some embodiments, the housing is provided with a mounting hole.

[0014] To solve the problem of the existing steering system occupying a large amount of horizontal space, the present application has the following advantages:

[0015] In the technical scheme, the driving gear set is arranged to transmit the driving force generated by the driver to the lead screw unit, the input shaft is arranged to transmit the operation force of the driver to the lead screw unit, the driving force generated by the driver and the operation force of the driver are simultaneously transmitted to the lead screw unit by the power-assisted unit, the power-assisted function is provided for the steering operation, and the transmission assembly and the power-assisted assembly are arranged in the first cavity and the second cavity respectively, and the central axis of the driver in the power-assisted assembly is parallel to the lead screw of the lead screw unit, so that the horizontal space occupation is greatly reduced. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 An overall structure schematic diagram of a parallel steering system of an embodiment is shown;

[0017] Figure 2 An internal structure schematic diagram of a parallel steering system of an embodiment is shown;

[0018] Figure 3 A bottom view structure schematic diagram of the internal structure of a parallel steering system of an embodiment is shown;

[0019] Figure 4 A lateral section structure schematic diagram of a first cavity of an embodiment is shown;

[0020] Figure 5 A lateral section structure schematic diagram of a second cavity of an embodiment is shown.

[0021] Reference signs: 10 - housing 10; 11 - first cavity 11; 111 - first support wall 111; 112 - second support wall 112; 113 - reinforcing wall 113; 12 - second cavity 12; 121 - third support wall 121; 122 - fourth support wall 122; 13 - mounting hole 13; 20 - transmission assembly 20; 21 - input shaft 21; 22 - lead screw unit 22; 221 - lead screw 221; 222 - nut 222; 223 - sector gear 223; 224 - output shaft 224; 30 - power-assisted assembly 30; 31 - driver 31; 32 - speed reducer 32; 33 - first gear 33; 34 - second gear 34; 40 - rotation sensor 40. DETAILED DESCRIPTION

[0022] The present disclosure will now be discussed with reference to a number of example embodiments. It should be appreciated that these embodiments are discussed solely for the purpose of enabling those with ordinary skill in the art to better understand and therefore practice the present disclosure, and are not intended to impose any limitations on the scope of the present disclosure.

[0023] As used herein, the term "includes" and its variants are to be read as open-ended terms that mean "includes, but is not limited to." The term "based on" is to be construed as "based at least in part on." The terms "a" and "an" are to be construed as "at least one" The term "another" is to be construed as "at least one other." The terms "on," "under," "to," "above," "below," "left," "right," "front," "back," "top," "bottom," "inner," "outer," "vertical," "horizontal," "lateral," "longitudinal," and terms of similar import, without more context, should be interpreted as indicating a spatial or positional relationship between entities as illustrated in the figures and are not to be construed as implying any specific spatial or positional relationship or order of operation. These terms are used merely for the sake of description and are not intended to limit the scope of the application or the embodiments thereof. In addition, certain terminology can also be used in the description for the sake of clarity. For example, the term "on" can mean on, above, or in, unless otherwise specified. For one of ordinary skill in the art to which this application pertains, the specific meaning of these terms in the context of the present application will be apparent from the following description. Furthermore, the terms "mount," "provide," "have," "set," "connect," "couple," "link," etc., should be construed broadly and will be used in connection with the accompanying drawings to connote a relationship between entities or elements as shown, and also to connote any spatial or positional relationship or order of operation between entities or elements. For one of ordinary skill in the art to which this application pertains, the specific meaning of these terms in the context of the present application will be apparent from the following description. In addition, the terms "first," "second," etc., are used herein only to distinguish one element from another, and do not necessarily have an ordinal or chronological significance. Unless otherwise stated, the term "plurality" means two or more.

[0024] The present embodiments disclose a parallel steering system, such as Figures 1-5As shown, can include: the shell 10, transmission assembly 20 and booster assembly 30; the shell 10 includes the first cavity 11 and the second cavity 12 extending in the same direction; transmission assembly 20 includes the input shaft 21 and screw unit 22, screw unit 22 includes the screw 221, nut 222, sector gear 223 and output shaft 224, screw 221 and input shaft 21 coaxial transmission connection, nut 222 is traditionally set on the screw 221, nut 222 is provided with a transmission tooth on the side of the sector gear 223, sector gear 223 and transmission tooth matching, nut 222 can move along the extension direction of the screw 221, to drive sector gear 223 swing, output shaft 224 and sector gear 223 coaxially arranged; booster assembly 30 includes the driver 31 and drive gear set, drive gear set includes the first gear 33 and the second gear 34, the first gear 33 is connected with the driver 31, the second gear 34 is connected with the screw 221, the first gear 33 and the second gear 34 transmission connection; transmission assembly 20 is arranged in the first cavity 11, booster assembly 30 is arranged in the second cavity 12, the screw 221 and the axis of the driver 31 are arranged in parallel.

[0025] In the above technical scheme, the drive gear set is arranged to transmit the driving force generated by the driver 31 to the screw unit 22, the screw unit 22 is connected with the input shaft 21, the input shaft 21 is used to transmit the operation of the driver to the screw unit 22, and the screw unit 22 can receive the operation force of the driver and the driving force generated by the driver 31 by means of the booster unit, so as to achieve the function of providing assistance for steering operation. On this basis, the transmission assembly 20 and the booster assembly 30 can be arranged in the first cavity 11 and the second cavity 12 respectively by means of the arrangement of the drive gear set, and the central axis of the driver 31 in the booster assembly 30 can be parallel to the screw 221 of the screw unit 22, thereby greatly reducing the horizontal space occupation.

[0026] It should be noted that the driver 31 can be a motor or other structure capable of generating driving force, such as a cylinder or other structure that can convert linear driving force into rotational driving force, and thus, a motor is preferably used as an embodiment. The lead screw unit 22 can convert a large range of rotational motion of the input shaft 21 into a small angle of oscillation of the output shaft 224, and in general, the angle between the driving tire and the forward direction is adjusted to achieve the purpose of adjustment, and a small angle such as a direct adjustment angle will cause a slight rotation operation of the driver to cause the tire to be turned by an equal ratio, which will make the adjustment of the angle difficult and imprecise, and the driving motion of the adjustment is scaled, i.e., when the input shaft 21 is rotated to adjust a large angle, the rotation angle of the output shaft 224 is small, thereby achieving the purpose of precise control. The length of the lead screw 221 is set in the lead screw unit 22 to limit the movement range of the nut 222, thereby limiting the oscillation angle of the sector gear connected thereto, thereby further achieving the purpose of limiting the rotatable angle of the output shaft 224 to prevent excessive rotation of the driving tire. In addition, the lead screw unit 22 can actually function to amplify the force, thereby reducing the need for operating force to a certain extent.

[0027] In terms of structure, the input shaft 21 can be connected to the lead screw 221 as a whole, i.e., the input shaft 21 is one end of the lead screw 221, so that the input shaft 21 and the lead screw 221 rotate simultaneously, and as an alternative embodiment, the input shaft 21 can be completely disconnected from the lead screw 221, the control action of the input shaft 21 is captured by a sensor or the like, and further controlled by a control device to directly control the driver 31 to generate driving force to drive the rotation of the lead screw 221, which can make the arrangement position of the input shaft 21 and the lead screw 221 more flexible, and since the rotation of the input shaft 21 has almost no resistance, the control force applied by the driver can be effectively reduced, but this can also make the driver lose the feeling of control, and thus, a damping structure or the like can be further provided to increase the actual operation feeling of the driver. When the power assisting assembly 30 fails, the driver will completely lose the steering control ability of the vehicle when the input shaft 21 and the lead screw 221 are disconnected, and when the power assisting assembly 30 fails to generate power, the driver can still forcibly control the rotation of the lead screw 221 by increasing the control force.

[0028] In order to drive the sector gear 223 to swing, the action force between the nut 222 and the sector gear 223 in the direction perpendicular to the tooth surface can generate the action force perpendicular to the central axis of the screw rod 221, so that the middle part of the screw rod 221 tends to bend away from the sector gear 223. Especially for commercial vehicles, when driving the wheels to turn, more friction needs to be overcome, so the action force is more significant. In order to resist the action force, the traditional scheme can only prevent the bending of the screw rod 221 by enhancing the structural strength of the screw rod 221, but this will also increase the diameter of the screw rod 221, resulting in the increase of its own weight, at the same time, it will also cause the volume of the nut 222 on it to increase accordingly, and further cause the volume of the first cavity 11 to increase. This series of changes will cause the overall volume of the device to increase significantly. In order to reduce the volume of the device to a certain extent, as shown in Figure 2 、 Figure 3 The sector gear 223 is arranged on the first side of the screw rod 221, and the first gear 33 is arranged on the second side of the screw rod 221, and the first side and the second side are arranged opposite to each other. The included angle between the sector gear 223 and the first gear 33 is 150° to 180°. By arranging the position of the first gear 33 on the side of the sector gear 223 opposite to the screw rod 221, when the reaction force generated by driving the sector gear 223 causes the screw rod 221 to tend to bend towards the second side thereof, the first gear 33 can provide support force for it. Generally, the driver 31 and the first gear 33 are coaxially arranged, and the first gear 33 can be fixed in the second cavity 12 through a rotating shaft. Therefore, the structure formed by the second cavity 12, the rotating shaft and the first gear 33 can support the second gear 34 to provide a reverse support force for the screw rod 221 to prevent it from bending. The included angle between the sector gear 223 and the first gear 33 is 150° to 180°, and preferably 170° to 180°.

[0029] In actual use, since the screw rod 221 will inevitably bear the reaction force of driving the sector gear 223, and the two ends of the screw rod 221 are respectively rotatably connected to the two ends of the first cavity 11, the two ends of the first cavity 11 need to bear the above-mentioned reaction force. In order to ensure the strength of the support of the screw rod 221, as shown in Figure 4 The first cavity 11 includes a first support wall 111 and a second support wall 112 away from the input shaft 21. The input shaft 21 penetrates the first support wall 111 and extends into the first cavity 11. The input shaft 21 is supported on the first support wall 111, and one end of the screw rod 221 is supported on the second support wall 112. The thickness of the second support wall 112 is greater than the thickness of the first support wall 111.

[0030] Due to the supporting force of the first gear 33, the second end of the lead screw 221 actually includes the supporting force brought by the power-assisted assembly 30 in the opposite direction of the acting force and the supporting force brought by the connection of the first supporting wall 111, but the other end of the lead screw 221 only has the supporting force provided by the second supporting wall 112, in order to ensure the strength of the supporting part, the thickness of the second supporting wall 112 is set to be greater than that of the first supporting wall 111, so as to reduce the material of the first supporting wall 111 and further reduce the total weight of the product under the condition of ensuring the strength.

[0031] Since the main resistance for driving the first gear 33 actually comes from the friction force of the wheels, especially for commercial vehicles due to the requirement of self-weight and load, the friction force between the wheels and the ground is particularly large, in order to overcome the resistance, the driver 31 needs to be able to output larger torque rather than rotation speed, in order to increase the torque output by the driver 31, as shown in Figure 2 The power-assisted assembly 30 further includes a speed reducer 32, which is arranged between the driver 31 and the first gear 33, and is in transmission connection with the driver 31 and the first gear 33, respectively. The speed reducer 32 is arranged in the second cavity 12. The arrangement of the speed reducer 32 can slow down the rotation speed of the shaft of the driver 31, so as to convert the driving force into more torque, so as to better overcome the resistance to realize steering.

[0032] As a specific embodiment, as shown in Figure 5 The second cavity 12 includes a third supporting wall 121 and a fourth supporting wall 122, the third supporting wall 121 is used for supporting and fixing the driver 31, and the first gear 33 is rotatably connected to the third supporting wall 121 and the fourth supporting wall 122 through a rotating shaft, respectively. The arrangement of the third supporting wall 121 can stably fix the driver 31 on the shell 10, and at the same time, as the two end parts of the second cavity 12, the third supporting wall 121 and the fourth supporting wall 122 support the rotating shaft structure of the first gear 33 at the same time.

[0033] As a more preferred embodiment, the speed reducer 32 is a cycloidal pin wheel speed reducer 32. The single-stage transmission efficiency of the cycloidal pin wheel speed reducer 32 is as high as 90%-97%, the energy loss is low, and it is significantly better than the traditional gear reducer, and at the same time has the advantages of high single-stage transmission ratio, zero-backlash design, high positioning accuracy; the structure adopts the principle of cycloidal pin gear meshing and planetary transmission, its unique smooth structure can replace ordinary cylindrical gear reducers and worm gear reducers in many cases, the cycloidal pin wheel speed reducer 32 allows continuous operation and allows forward and reverse rotation, so it is very suitable for the parallel steering system in the application.

[0034] In order to further strengthen the supporting effect of the first supporting wall 111, as shown in Figure 1As shown, the first support wall 111 and the second support wall 112 are connected and enclosed by a first wall body to form a first cavity 11. The actuator 31 includes an actuator 31 housing, and the first wall body and the actuator 31 housing are connected by a reinforcing wall 113. The reinforcing wall 113 connects the first wall body and the actuator 31 housing into a whole, thereby further strengthening the support and fixing effect on the lead screw 221 on the opposite side of the sector gear 223, and greatly increasing the reinforcement of the housing 10 structure with less material usage.

[0035] As a specific implementation method, in order to reduce the friction between the lead screw 221 and the lead nut 222, such as... Figure 2 , Figure 4 As shown, the lead screw nut 222 includes a lead screw nut 222 seat, a ball return device is provided on the lead screw nut 222 seat, and balls are provided between the lead screw nut 222 seat and the lead screw 221. The balls can roll along the track formed by the lead screw nut 222 seat, the lead screw 221, and the ball return device. With the above structure, the friction loss is small, the transmission efficiency is significantly higher than that of ordinary sliding lead screws, and the energy conversion is more efficient; the rolling friction resistance is extremely small, the movement speed is not affected, and the starting torque is low; the axial stiffness is high, and high axial load can be achieved; by utilizing the cyclic rolling of the balls, the friction between the lead screw 221 and the lead screw nut 222 is reduced, making the operation of the lead screw nut 222 more stable and smooth.

[0036] Furthermore, the parallel steering system also includes a control component and a rotation sensor 40. The rotation sensor 40 is located at the input shaft 21 and can detect the rotation of the input shaft 21. The control component is communicatively connected to both the rotation sensor 40 and the driver 31, and can control the operation of the driver 31 based on the rotation of the input shaft 21. The rotation sensor 40 can detect rotation information such as the rotation angle, rotation direction, and force of the input shaft 21. Through processing by the control component, the rotation direction of the driver 31 is controlled, thereby achieving power assist control based on the input information from the input shaft 21.

[0037] Because the transmission system needs to be fixed to the vehicle body, such as Figure 1 As shown, the housing 10 is provided with mounting holes 13.

[0038] Those skilled in the art will understand that the above embodiments are specific examples of implementing this disclosure, and in practical applications, various changes can be made in form and detail without departing from the scope of this disclosure.

Claims

1. A parallel steering system, characterized by, The parallel type steering system comprises: a housing, a transmission assembly and a power-assisted assembly; the housing comprises a first cavity and a second cavity extending in the same direction; the transmission assembly comprises an input shaft and a screw unit, the screw unit comprises a screw, a nut, a sector gear and an output shaft, the screw is coaxially connected with the input shaft, the nut is sleeved on the screw, the nut is provided with transmission teeth on the side facing the sector gear, the sector gear is matched with the transmission teeth, the nut can move along the extension direction of the screw to drive the sector gear to swing, and the output shaft is coaxially arranged with the sector gear; the power-assisted assembly comprises a driver and a driving gear set, the driving gear set comprises a first gear and a second gear, the first gear is connected with the driver, the second gear is connected with the screw, and the first gear is in transmission connection with the second gear; the transmission assembly is arranged in the first cavity, the power-assisted assembly is arranged in the second cavity, and the screw and the axis of the driver are arranged in parallel; the sector gear is arranged on the first side of the screw, the first gear is arranged on the second side of the screw, and the first side and the second side are arranged oppositely; the first cavity comprises a first support wall and a second support wall away from the input shaft, the input shaft penetrates through the first support wall and extends into the first cavity, the input shaft is supported on the first support wall, one end of the screw is supported on the second support wall, and the other end of the screw is supported by the power-assisted assembly; the thickness of the second support wall is greater than that of the first support wall.

2. The parallel type steering system according to claim 1, wherein the power-assisted assembly further comprises a speed reducer, the speed reducer is arranged between the driver and the first gear, the speed reducer is in transmission connection with the driver and the first gear respectively, and the speed reducer is arranged in the second cavity.

3. The parallel type steering system according to claim 1, wherein the second cavity comprises a third support wall and a fourth support wall, the third support wall is used for supporting and fixing the driver, and the first gear is rotatably connected to the third support wall and the fourth support wall through a rotating shaft respectively.

4. The parallel type steering system according to claim 2, wherein the speed reducer is a cycloidal pin wheel speed reducer.

5. The parallel type steering system according to claim 1, wherein the first support wall and the second support wall are connected by a first wall body to form the first cavity, the driver comprises a driver shell, and the first wall body and the driver shell are connected through a reinforcing wall.

6. The parallel type steering system according to claim 1, wherein the nut comprises a nut seat, a ball returning device is arranged on the nut seat, balls are arranged between the nut seat and the screw, and the balls can roll along the track formed by the nut seat, the screw and the ball returning device. 7.The parallel steering system according to claim 1, wherein the parallel steering system further comprises a control assembly and a rotation sensor, the rotation sensor is arranged on the input shaft, and the rotation sensor is capable of detecting the rotation of the input shaft. The control assembly is in communication with the rotation sensor and the driver, respectively, and the control assembly is capable of controlling the operation of the driver according to the rotation of the input shaft. 8.The parallel steering system according to claim 1, wherein the housing is provided with a mounting hole. ​ ​

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