Limiting device and steer-by-wire system

Abstract

The invention provides a limiting device and a steer-by-wire system. The limiting device comprises a steering shaft assembly and a limiting assembly. The other end of the steering shaft assembly is movably connected with the limiting assembly; the limiting assembly comprises a rotating part and a limiting part, the rotating part is rotationally connected with the limiting part, and the rotating part is in clearance fit with the steering shaft assembly; the surface of the side, away from the steering shaft assembly, of the limiting part and the surface of the side, close to the limiting part, of the steering shaft assembly are limiting end faces. The rotating shaft assembly is driven by the steering wheel to rotate, and then the rotating part is driven to rotate along the limiting part and axially move along the steering shaft assembly, so that the rotating part makes contact with the limiting end face, and angle limiting of the steering wheel is achieved. Through the limiting device, limiting of the limiting position of the steering wheel can be achieved within a limited stroke, a clock spring is protected, and the situation that rotation of the steering wheel cannot be limited due to software failure is prevented; the device is simple in structure, convenient to install, small in size and beneficial to arrangement of the whole vehicle.

Description

Technical Field

[0001] The present invention relates to the technical field of automotive steering systems, and particularly to a limiting device and a steer-by-wire system. Background Art

[0002] Since the intermediate shaft in the electric power steering system is cancelled in the steer-by-wire system, the mechanical decoupling of the steering column and the steering actuator is realized, but the limiting mechanism on the steering actuator cannot limit the number of turns of the steering wheel.

[0003] Under the energized working condition, the steer-by-wire system realizes the end limiting function through software control. However, under the power-off working condition, there is no limit to the left and right extreme positions of the steering shaft, which will cause the steering wheel to rotate freely in the left and right directions. In severe cases, the clock spring in the combination switch may be damaged. Therefore, it is necessary to design a limiting device on the steering column to limit the number of turns of the steering wheel in the power-off state. However, the limiting devices in the prior art still have the disadvantages of complex structure, large volume, poor assembly processability, low limiting strength, high manufacturing cost, and the structure of the limiting device cannot meet the needs of all customers in the market.

[0004] Therefore, there is an urgent need for a limiting device that can not only limit the extreme position of the steering wheel within a limited stroke under the power-off working condition, but also has a simple structure, is convenient to install, has high strength, has a small size, and is applicable to different stroke requirements. Summary of the Invention

[0005] To solve this technical problem, the technical solutions provided in the present application are as follows:

[0006] On the one hand, the present invention provides a limiting device, including a steering shaft assembly and a limiting assembly; one end of the steering shaft assembly is connected to the steering wheel, and the other end is movably connected to the limiting assembly;

[0007] The limiting assembly includes a rotating part and a limiting part. The rotating part and the limiting part are rotatably connected, and the rotating part is in clearance fit with the steering shaft assembly; wherein, the surface of the limiting part away from the steering shaft assembly and the surface of the steering shaft assembly close to the limiting part are both limiting end faces;

[0008] The rotating shaft assembly rotates under the drive of the steering wheel, and then drives the rotating part to rotate along the limiting part and move axially along the steering shaft assembly, so that the rotating part contacts the limiting end face, thereby realizing angle limitation of the steering wheel.

[0009] In some possible implementation manners, a rotating part helical surface is arranged on the side surface of the rotating part, a limiting part helical groove is arranged inside the limiting part, and the rotating directions of the rotating part helical surface and the limiting part helical groove are the same;

[0010] The rotating part and the limiting part are in spiral fit through the spiral groove of the limiting part and the spiral surface of the rotating part;

[0011] Wherein, the area of the spiral surface of the rotating part is the first area, the side area of the rotating part is the second area, and the ratio range of the first area to the second area is one fifth to one third.

[0012] In some possible implementation manners, the steering shaft assembly includes a steering shaft and a steering shaft guide column, and the steering shaft and the steering shaft guide column are an integrally formed structure;

[0013] One end of the steering shaft is connected to the steering wheel, and the steering shaft guide column is arranged at the other end of the steering shaft.

[0014] In some possible implementation manners, the limiting end surface includes a first limiting surface and a second limiting surface. The first limiting surface is the surface on one side of the steering shaft close to the rotating part, and the second limiting surface is the surface on one side of the limiting part away from the rotating part; The surface on one side of the rotating part close to the first limiting surface is the first surface, and the surface on the side away from the first limiting surface is the second surface;

[0015] When the first surface contacts the first limiting surface, or the second surface contacts the second limiting surface, the steering wheel stops rotating, thereby realizing the angle limit of the steering wheel.

[0016] In some possible implementation manners, a rotating part guide groove is arranged on the rotating part;

[0017] The steering shaft guide column passes through the rotating part through the rotating part guide groove, and the steering shaft guide column and the rotating part guide groove are in clearance fit;

[0018] The outer surface of the steering shaft guide column and the inner surface of the rotating part guide groove are both arc-shaped.

[0019] In some possible implementation manners, the limiting device further includes a fixed base, and the rotating shaft assembly is arranged in the fixed base;

[0020] The fixed base includes a housing, a bearing and a snap ring, and a snap ring groove for cooperating with the snap ring is further arranged on the housing;

[0021] The assembly manner of the bearing and the housing is interference fit, and the snap ring is arranged in the snap ring groove to fix the bearing.

[0022] In some possible implementation manners, the steering shaft assembly further includes a hexagon nut;

[0023] The steering shaft and the inner ring of the bearing are in clearance fit, and the hexagon nut is used to fix the steering shaft to limit the radial freedom and axial freedom of the steering shaft.

[0024] In some possible embodiments, the limiting assembly further includes a plurality of bolts. A plurality of fixing holes are provided on the limiting portion, and a plurality of limiting portion threaded holes are further provided on the housing;

[0025] The plurality of bolts pass through the plurality of fixing holes and the plurality of limiting portion threaded holes to fix the limiting portion to the housing, and the end face of the limiting portion contacts the end face of the housing.

[0026] In some possible embodiments, the materials of the rotating portion and the limiting portion are alloy structural steel, and the alloy structural steel is subjected to quenching and tempering treatment and carburizing treatment.

[0027] On the other hand, the present application also provides a steer-by-wire system, including the above-mentioned limiting device.

[0028] On the other hand, an embodiment of the present application also provides a vehicle, and the vehicle includes the above-mentioned steer-by-wire system.

[0029] An embodiment of the present application provides a limiting device and a steer-by-wire system. The limiting device includes a steering shaft assembly and a limiting assembly; one end of the steering shaft assembly is connected to the steering wheel, and the other end is movably connected to the limiting assembly; the limiting assembly includes a rotating portion and a limiting portion, the rotating portion and the limiting portion are rotatably connected, and the rotating portion and the steering shaft assembly are in clearance fit; wherein, the surface of the limiting portion away from the steering shaft assembly and the surface of the steering shaft assembly close to the limiting portion are both limiting end faces; the rotating shaft assembly rotates driven by the steering wheel, and then drives the rotating portion to rotate along the limiting portion and move axially along the steering shaft assembly, so that the rotating portion contacts the limiting end face, thereby realizing angle limitation of the steering wheel. Through the above-mentioned limiting device, the limit of the extreme position of the steering wheel can be realized within a limited stroke, so that the clock spring can be protected, and the rotation of the steering wheel caused by software failure can be prevented from being unrestricted; and the device has the advantages of simple structure, convenient installation, small volume, etc., which is beneficial to the overall vehicle layout, and can also meet the requirements of different customers by adjusting the distance between the two limiting end faces. Description of the Drawings

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained according to these drawings.

[0031] Figure 1 It is a schematic structural diagram of a limiting device provided by an embodiment of the present application;

[0032] Figure 2 It is an exploded view of a limiting device provided by an embodiment of the present application;

[0033] Figure 3 It is a cross-sectional view of a limiting device provided by an embodiment of the present application;

[0034] Figure 4 It is a schematic structural diagram of the installation relationship between a steering shaft and a rotating part provided by an embodiment of the present application;

[0035] Figure 5 It is a schematic structural diagram of a limiting cover provided by an embodiment of the present application;

[0036] Among them, the corresponding reference numerals in the figure are as follows:

[0037] 100 - Steering shaft assembly; 1 - Housing 1; 2 - Bearing; 3 - Snap ring; 4 - Steering shaft; 5 - Hexagonal nut; 6 - Rotating part; 7 - Limiting part; 8 - Bolt; 9 - First limiting surface; 10 - First surface; 11 - Second surface; 12 - Second limiting surface; 13 - Rotating part guide groove; 14 - Steering shaft guide post; 15 - Rotating part spiral surface; 16 - Limiting part spiral groove; 17 - Fixing hole. Detailed implementation manners

[0038] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present application.

[0039] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and do not necessarily need to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of the present application described here can be implemented in an order other than those illustrated or described here. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or server including a series of steps or units does not necessarily need to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0040] In the description of the present application, it should be understood that the orientation or positional relationships indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. are based on the orientation or positional relationships shown in the drawings. These are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Since the embodiments disclosed in the present application can be arranged in different directions, these terms indicating directions should only be regarded as illustrative and not as limitations. For example, "upper" and "lower" are not necessarily limited to the directions opposite to or consistent with the direction of gravity. In addition, features defined as "first" and "second" may explicitly or implicitly include one or more of such features.

[0041] When a numerical range is disclosed herein, the above range is considered continuous and includes the minimum and maximum values of the range, as well as each value therebetween. Further, when the range refers to integers, it includes each integer between the minimum and maximum values of the range. In addition, when multiple ranges are provided to describe features or characteristics, the ranges may be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all sub-ranges subsumed therein. For example, the specified range from "1 to 10" should be considered to include any and all sub-ranges between the minimum value 1 and the maximum value 10. Exemplary sub-ranges of the range 1 to 10 include, but are not limited to, 1 to 6.1, 3.5 to 7.8, 5.5 to 10, etc.

[0042] A traditional electric power steering system generally consists of a steering column, an intermediate shaft, a steering actuator, etc. The number of turns of the steering wheel is determined by the mechanical structure on the steering actuator. However, since the steer-by-wire system cancels the intermediate shaft and realizes the mechanical decoupling of the steering column and the steering actuator, the limit mechanism on the steering actuator cannot limit the number of turns of the steering wheel.

[0043] Under the energized condition, the steer-by-wire system realizes the end limit function through software control. However, under the de-energized condition, there is no limit to the left and right extreme positions of the steering shaft, which will cause the steering wheel to rotate freely in the left and right directions. In severe cases, the clock spring in the combination switch may be damaged.

[0044] Based on this, the embodiments of the present application provide a limiting device. Figure 1The structural schematic diagram of a limiting device provided by an embodiment of the present application. The limiting device is connected to the steering wheel and is used to limit the extreme position of the steering wheel within a limited stroke, so as to protect the clock spring and prevent the steering wheel from rotating unrestricted due to software failure. Specifically, as Figure 2 shown, the limiting device includes a steering shaft assembly 100 and a limiting assembly; one end of the steering shaft assembly 100 is connected to the steering wheel, and the other end is movably connected to the limiting assembly;

[0045] The limiting assembly includes a rotating part 6 and a limiting part 7. The rotating part 6 is rotatably connected to the limiting part 7, and the rotating part 6 is in clearance fit with the steering shaft assembly 100; wherein, one side surface of the limiting part 7 away from the steering shaft assembly 100 and one side surface of the steering shaft assembly 100 close to the limiting part 7 are both limiting end faces;

[0046] The rotating shaft assembly rotates under the drive of the steering wheel, and then drives the rotating part 6 to rotate along the limiting part 7 and move axially along the steering shaft assembly 100, so that the rotating part 6 contacts the limiting end face, thereby realizing angle limitation of the steering wheel.

[0047] In the embodiment of the present application, both ends of the steering shaft assembly 100 are respectively connected to the steering wheel and the limiting assembly. Specifically, it is connected to the steering column of the steering wheel. The steering shaft assembly 100 is used to rotate under the drive of the steering wheel, so as to drive the limiting assembly to operate; the limiting assembly is used to provide a rotational resistance moment to the steering wheel in the event of a failure in the electronic control system of the in-wireless steering system feel simulator or under the power-off condition, limit the number of turns of the steering wheel rotation, and protect the clock spring.

[0048] Specifically, the limiting assembly includes a rotating part 6 and a limiting part 7. The connection method between the rotating part 6 and the limiting part 7 is a rotational connection. Here, the rotational connection means that the rotating part 6 can rotate along the inner shell or the outside of the limiting part 7. When reaching the limiting end face, the rotating part 6 will no longer be able to rotate. During this process, the limiting part 7 is fixed and plays a role of supporting and limiting the rotation of the rotating part 6. And the rotating part 6 is in clearance fit with the steering shaft assembly 100. The clearance fit means a fit with a clearance (including the minimum clearance equal to zero). In the embodiment of the present application, it means that there is a certain clearance or clearance tolerance range between the rotating part 6 and the steering shaft assembly 100, so that the rotating part 6 and the steering shaft assembly 100 can move relative to each other during assembly, that is, the rotating part 6 can move relatively.

[0049] The limiting end faces in the embodiments of the present application include the surface of the limiting portion 7 away from the steering shaft assembly 100 and the surface of the steering shaft assembly 100 close to the limiting portion 7. The function of setting two limiting end faces is that no matter whether the steering wheel rotates clockwise or counterclockwise, when the rotating portion 6 reaches the limiting end face, the steering wheel can be stopped from rotating, so as to realize the angle limitation of the steering wheel.

[0050] The operating principle of the limiting device provided by the embodiments of the present application is as follows: when a fault occurs in the electric control system or under the condition of powering off, when the steering wheel rotates, it will drive the steering shaft assembly 100 to rotate. The steering shaft assembly 100 drives the rotating portion 6 to rotate along the limiting portion 7 and move axially along the steering shaft assembly 100. When the steering wheel rotates to a preset angle, the rotating portion 6 contacts the limiting end face, and the steering wheel cannot rotate, so the angle limitation of the steering wheel is realized.

[0051] Optionally, in order to realize the rotational connection between the limiting portion 7 and the rotating portion 6, the two can be in threaded cooperation, or can be arranged in the ways of guide rail and slider, chute and slider, etc.

[0052] Optionally, when the limiting portion 7 and the rotating portion 6 are in threaded cooperation, the limiting portion 7 can be a limiting cover, and the rotating portion 6 can be a limiting block, that is, the limiting block can be rotated around the limiting cover.

[0053] Through the above limiting device, the embodiments of the present application can realize the limit of the extreme position of the steering wheel within a limited stroke, so as to protect the clock spring and prevent the steering wheel from rotating unrestrictedly due to software failure. Moreover, the device has the advantages of simple structure, convenient installation, small volume, etc., which is beneficial to the vehicle layout, and can also meet the requirements of different customers by adjusting the distance between the two limiting end faces.

[0054] As an optional implementation manner, a rotating portion spiral surface 15 is arranged on the side surface of the rotating portion 6, a limiting portion spiral groove 16 is arranged inside the limiting portion 7, and the rotating directions of the rotating portion spiral surface 15 and the limiting portion spiral groove 16 are the same;

[0055] The rotating portion 6 and the limiting portion 7 are in spiral cooperation through the limiting portion spiral groove 16 and the rotating portion spiral surface 15. Among them, the area of the rotating portion spiral surface 15 is the first area, the side surface area of the rotating portion 6 is the second area, and the ratio range of the first area to the second area is one-fifth to one-third.

[0056] In the embodiments of the present application, as Figure 3As shown in the figure, when the limiting part 7 and the rotating part 6 are in screw fit, a rotating part spiral surface 15 is provided on the side surface of the rotating part 6, and a limiting part spiral groove 16 that cooperates with the rotating part spiral surface 15 is provided inside the limiting part 7. Moreover, the rotation directions of the rotating part spiral surface 15 and the limiting part spiral groove 16 are the same, so that the rotating part 6 and the limiting part 7 can be in spiral fit through the limiting part spiral groove 16 and the rotating part spiral surface 15.

[0057] Furthermore, in order to reduce the contact area between the limiting part 7 and the rotating part 6 and lower the frictional force, the ratio of the area of the rotating part spiral surface 15 to the side surface area of the rotating part 6 is set between one-fifth and one-third, and it can be selected according to actual needs.

[0058] Optionally, the ratio of the first area to the second area is preferably one-fourth.

[0059] Optionally, a large amount of lithium-based lubricating oil, that is, lithium-based grease, is applied inside the limiting part spiral groove 16, which can effectively reduce the frictional resistance caused by the limiting device and affect the feel of the steering wheel.

[0060] It should be noted that the rotating part spiral surface 15 must penetrate the axial direction of the side surface of the rotating part 6, that is, to ensure that when the rotating part 6 moves axially, a spiral surface must be provided in the circumferential direction at any position of it. That is, one-fifth to one-third refers to one-fifth of a circle to one-third of a circle.

[0061] In the embodiment of the present application, by providing a spiral surface on the side surface of the rotating part 6 and a spiral groove in the limiting part 7, the rotating part 6 and the limiting part 7 are in screw fit. And by setting the spiral surface to be from one-fifth of a circle to one-third of a circle, and applying a large amount of lithium-based lubricating oil inside the limiting part spiral groove 16, a low-friction spiral design is realized, effectively reducing the influence of noise during the steering process. It can also ensure a low contact area and low roughness, thereby effectively reducing the frictional resistance caused by the limiting device and affecting the feel of the steering wheel, ensuring that the limit position of the steering wheel can be limited within a limited stroke, thus protecting the clock spring and preventing the steering wheel from rotating uncontrollably due to software failure. And this device has the advantages of simple structure, convenient installation, small volume, etc., which is beneficial to the vehicle layout.

[0062] As an alternative embodiment, the steering shaft assembly 100 includes a steering shaft 4 and a steering shaft guide post 14, and the steering shaft 4 and the steering shaft guide post 14 are of an integrally formed structure;

[0063] One end of the steering shaft 4 is connected to the steering wheel, and the steering shaft guide post 14 is arranged at the other end of the steering shaft 4.

[0064] As an alternative embodiment, a rotating part guide groove 13 is provided on the rotating part 6;

[0065] The steering shaft guide column 14 passes through the rotating part 6 through the rotating part guide groove 13, and the steering shaft guide column 14 and the rotating part guide groove 13 are in clearance fit;

[0066] The outer surface of the steering shaft guide column 14 and the inner surface of the rotating part guide groove 13 are both arc-shaped.

[0067] In the embodiment of the present application, as Figure 3 and Figure 4 shown, the steering shaft assembly 100 includes a steering shaft 4 and a steering shaft guide column 14, and the steering shaft 4 and the steering shaft guide column 14 are of an integrally formed structure. One end of the steering shaft 4 is connected to a steering wheel, and the other end is provided with the steering shaft guide column 14.

[0068] As Figure 4 shown, a rotating part guide groove 13 is provided on the rotating part 6. The rotating part guide groove 13 is used to make the rotating part 6 and the steering shaft guide column 14 in clearance fit. Specifically, the steering shaft 4 penetrates through the rotating part 6, and the rotating part 6 is rotatably connected to the limiting part 7.

[0069] As Figure 5 shown, the outer surface of the steering shaft guide column 14 and the inner surface of the rotating part guide groove 13 are both arc-shaped. That is, an arc-shaped fit design is realized between the steering shaft guide column 14 and the rotating part 6. Specifically, an inner arc fit is used. The inner arc fit design means that an arc shape is used for connection or fit inside mechanical parts. In the embodiment of the present application, it means that the steering shaft guide column 14 serves as the bearing 2 in the arc fit, its outer surface is arc-shaped, and the inner surface of the rotating part guide groove 13 on the rotating part 6 is arc-shaped. Through this arc fit, a four-point contact design between the steering shaft guide column 14 and the rotating part guide groove 13 is realized, effectively reducing stress concentration, preventing wear caused by long-term use, and improving the service life. And the above-mentioned steering shaft guide column 14 and the rotating part 6 are in clearance fit, allowing free sliding or rotation between the hole and the shaft, and no jamming will occur.

[0070] It should be noted that the four-point contact design means that the function is realized through the contact of four points between the two. This design has the advantages of low friction, high precision, high reliability, compact structure design, high rotational speed performance, flexible installation and maintenance, and optimized design between the steering shaft guide column 14 and the rotating part 6.

[0071] Optionally, the clearance fit mode between the steering shaft guide column 14 and the rotating part guide groove 13 is specifically a small clearance fit.

[0072] In the embodiment of the present application, a clearance fit is adopted between the steering shaft guide column 14 and the rotating part 6. While ensuring the ultimate limit of the steering wheel, the arc fit and four-point contact reduce the friction and wear during the transmission process, and improve the service life.

[0073] As an alternative embodiment, the limiting device further includes a fixed base, and the rotating shaft assembly is arranged in the fixed base;

[0074] The fixed base includes a housing 1, a bearing 2 and a snap ring 3, and a snap ring groove for cooperating with the snap ring 3 is further arranged on the housing 1;

[0075] The assembly method of the bearing 2 and the housing 1 is interference fit, and the snap ring 3 is arranged in the snap ring groove to fix the bearing 2.

[0076] As an alternative embodiment, the steering shaft assembly 100 further includes a hexagon nut 5;

[0077] There is a clearance fit between the steering shaft 4 and the inner ring of the bearing 2, and the hexagon nut 5 is used to fix the steering shaft 4 to limit the radial freedom and axial freedom of the steering shaft 4.

[0078] As an alternative embodiment, the limiting component further includes a plurality of bolts 8, a plurality of fixing holes 17 are arranged on the limiting part 7, and a plurality of limiting part threaded holes are further arranged on the housing 1;

[0079] The plurality of bolts 8 pass through the plurality of fixing holes 17 and the plurality of limiting part threaded holes to fix the limiting part 7 on the housing 1, and the end face of the limiting part 7 contacts the end face of the housing 1.

[0080] In the embodiment of the present application, as Figure 2 and Figure 3 shown, the limiting device provided by the embodiment of the present application further includes a fixed base, and the fixed base is used to fix the steering shaft assembly 100 and the limiting component. Specifically, the fixed base includes a housing 1, a bearing 2 and a snap ring 3. The bearing 2 and the housing 1 are assembled with interference fit, and the snap ring 3 is snapped into the snap ring groove of the housing 11 to fix the bearing 22 (as Figure 3 shown), and this assembly is used as the fixed base for fixing the steering shaft 44. Among them, interference fit refers to a fit with interference. At this time, the size of the hole (here refers to the hole on the housing 1 for installing the bearing 2, which can be called the bearing 2 hole) is always smaller than the size of the bearing 2. External force needs to be applied during assembly to install the shaft into the hole. After assembly, a tight bond is generated between the hole and the shaft, which can transmit large loads and torques, and at the same time ensure the relative position accuracy between the two.

[0081] The steering shaft 4 has a clearance fit with the inner ring of the bearing 2 and is fixed with a hexagon nut 5 to limit the radial and axial degrees of freedom of the steering shaft 4 and ensure the rotational degree of freedom of the steering shaft 4 around its axis during the rotation following the steering wheel.

[0082] In the embodiment of the present application, the limiting component further includes a plurality of bolts 8. The bolts 8 are the fixing parts for the limiting part 7 and the rotating part 6. The specific installation method is as follows: A large amount of lithium-based grease is applied in the spiral groove 16 of the limiting part. The spiral surface 15 of the rotating part is inserted along the spiral groove 16 of the limiting part until the end face of the limiting part 7 contacts the end face of the housing 1 and the two fixing holes 17 of the limiting part 7 are aligned with the fixing holes 17 of the housing 1. The bolt 8 passes through the fixing hole 17 and is screwed into the threaded hole of the housing 11 to fix the limiting part 7.

[0083] Optionally, the plurality of bolts are preferably two and are symmetrically arranged.

[0084] Optionally, the fit tolerance of the clearance fit between the steering shaft 4 and the inner ring of the bearing 2 is the first tolerance, and the fit tolerance of the clearance fit between the steering shaft guide post 14 and the rotating part guide groove 13 is the second tolerance, and the second tolerance is less than the first tolerance.

[0085] In the embodiment of the present application, the steering shaft assembly 100 and the limiting part 7 assembly are installed through the fixed base, and by means of interference fit and spacing fit, etc., the installation accuracy and the rotational degree of freedom are ensured, making the limiting device have the advantages of simple structure, convenient installation, small volume, etc., which is beneficial to the vehicle layout.

[0086] As an optional implementation manner, the limiting end face includes a first limiting face 9 and a second limiting face 12. The first limiting face 9 is the surface on the side of the steering shaft 4 close to the rotating part 6, and the second limiting face 12 is the surface on the side of the limiting part 7 away from the rotating part 6. The surface on the side of the rotating part 6 close to the first limiting face 9 is the first surface 10, and the surface on the side away from the first limiting face 9 is the second surface 11.

[0087] When the first surface 10 contacts the first limiting face 9, or the second surface 11 contacts the second limiting face 12, the steering wheel stops rotating, thereby realizing the angle limit of the steering wheel.

[0088] In the embodiment of the present application, as Figure 3 shown, the limiting end face includes a first limiting face 9 and a second limiting face 12. The first limiting face 9 is the surface on the side of the steering shaft 4 close to the rotating part 6, and the second limiting face 12 is the surface on the side of the limiting part 7 not adjacent to the rotating part 6. When the first surface 10 or the second surface 11 of the rotating part 6 contacts the first limiting face 9 or the second limiting face 12, the rotating part 6 cannot rotate anymore, thereby making the steering wheel stop rotating, realizing the angle limit of the steering wheel.

[0089] Optionally, the first limiting surface 9 can also be referred to as the limiting end surface of the steering shaft 4, and the second limiting surface 12 can also be referred to as the limiting end surface of the limiting portion 7.

[0090] The working principle of the limiting device provided by the embodiment of the present application is as follows: when the steering wheel rotates, the steering shaft 4 causes the rotating portion 6 to rotate around the spiral groove 16 of the limiting portion. While the rotating portion 6 rotates around the spiral groove 16 of the limiting portion, it also makes an axial movement around the steering shaft guiding column 14. As the steering wheel rotates in different directions, it will drive the first surface 10 or the second surface 11 of the rotating portion 6 to contact the first limiting surface 9 or the second limiting surface 12 respectively. After contacting the limiting end surface, it will no longer be able to rotate, so as to achieve the function of limiting the angle of the steering wheel.

[0091] As an optional implementation manner, the embodiment of the present application also provides an application method of the limiting device, so that the limiting can be adapted to different customer requirements.

[0092] In the embodiment of the present application, the calculation method for limiting the angle of the steering wheel is as follows:

[0093] Assume that the maximum number of rotatable turns of the steering wheel is n, the thickness of the rotating portion 6 is the first thickness d, the pitch of the limiting portion 7 is s, and the distance between the first limiting surface 9 and the second limiting surface 12 is L. Then:

[0094] n = (L - d) / s;

[0095] To ensure the limiting strength, usually d and s are set as fixed values, and the number of turns n of the steering wheel is restricted by changing L, thereby realizing the angle limitation of the steering wheel.

[0096] In the embodiment of the present application, the stroke of the rotating portion 6 is restricted by the limiting end surface, thereby realizing the angle limitation of the steering wheel. And by changing the distance between the first limiting surface 9 and the second limiting surface 12, as well as the length of the spiral groove 16 of the limiting portion, it is possible to change the number of turns of the steering wheel according to different customer requirements, ensuring that the limit of the extreme position of the steering wheel can be realized within a limited stroke, thereby protecting the clock spring and preventing the steering wheel from rotating without limitation due to software failure.

[0097] As an optional implementation manner, the materials of the rotating portion 6 and the limiting portion 7 are alloy structural steel, and the alloy structural steel has been subjected to quenching and tempering treatment and carburizing treatment.

[0098] In the embodiment of the present application, in order to improve the mechanical strength of the rotating portion 6 and the limiting portion 7, the material used is alloy structural steel, and it is alloy structural steel that has been subjected to quenching and tempering treatment and carburizing treatment.

[0099] Alloy structural steel refers to steel used for mechanical parts and various engineering components and containing one or several alloying elements in a certain amount. Quenching and tempering treatment is a heat treatment process that provides the comprehensive mechanical properties of steel. It is a heat treatment process of high-temperature tempering after quenching of alloy structural steel. The purpose is to enable the steel parts to obtain high strength while also having good toughness and sufficient hardness, thus possessing comprehensive excellent mechanical properties. Carburizing treatment is used to provide the hardness and wear resistance of alloy structural steel while maintaining toughness and ductility. Carburizing is to place the workpiece made of low-carbon steel or low-carbon alloy steel in a carbon-rich active medium, heat it to 850 - 950 °C and hold for several hours, so that the carburizing medium decomposes active carbon atoms on the surface of the workpiece, and these carbon atoms penetrate into the surface layer of the workpiece through surface absorption and diffusion. After carburizing, the carbon content on the surface of the workpiece increases, forming a high-carbon layer.

[0100] Optionally, the technological process of quenching and tempering treatment includes processes such as heating, holding, quenching, and tempering.

[0101] Optionally, the carburizing technological process mainly includes the following stages: pretreatment, preparing the metal material and carburizing agent to be carburized; carburizing treatment, including processes such as heating, carbonization, and diffusion; post-treatment, including quenching and low-temperature tempering.

[0102] Optionally, the carburizing treatment method in the embodiments of the present application includes but is not limited to gas carburizing, vacuum carburizing, liquid carburizing, and solid carburizing (pack carburizing).

[0103] In the embodiments of the present application, the rotating part 6 and the limiting part 7 are manufactured from alloy structural steel through a forging process and are subjected to surface carburizing treatment, so that the limiting device not only solves the problem of limiting the extreme position of the steering wheel within a limited stroke, thereby protecting the clock spring and preventing the problem that the rotation of the steering wheel cannot be restricted due to software failure, but also enables the limiting device to have high strength and mechanical properties.

[0104] On the other hand, the embodiments of the present application also provide a steer-by-wire system, and the steer-by-wire system includes the above-mentioned limiting device.

[0105] On the other hand, the embodiments of the present application also provide a vehicle, and the vehicle includes the above-mentioned steer-by-wire system.

[0106] The above are only optional embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included within the protection scope of the present application.

Claims

1. A limiting device, characterized in that, It includes a steering shaft assembly (100) and a limiting assembly; one end of the steering shaft assembly (100) is connected to the steering wheel, and the other end is movably connected to the limiting assembly; The limiting assembly includes a rotating part (6) and a limiting part (7), the rotating part (6) is rotatably connected to the limiting part (7), and the rotating part (6) is in clearance fit with the steering shaft assembly (100); wherein, on one side surface of the limiting part (7) away from the steering shaft assembly (100) and on one side surface of the steering shaft assembly (100) close to the limiting part (7) are both limiting end faces; The rotating shaft assembly (100) rotates under the drive of the steering wheel, and then drives the rotating part (6) to rotate along the limiting part (7) and move axially along the steering shaft assembly (100), so that the rotating part (6) contacts the limiting end face, thereby realizing angle limitation of the steering wheel.

2. The limit device according to claim 1, characterized in that, A rotating part helical surface (15) is arranged on the side surface of the rotating part (6), a limiting part helical groove (16) is arranged inside the limiting part (7), and the rotating directions of the rotating part helical surface (15) and the limiting part helical groove (16) are the same; The rotating part (6) and the limiting part (7) are helically engaged through the limiting part helical groove (16) and the rotating part helical surface (15); Wherein, the area of the rotating part helical surface (15) is the first area, the side surface area of the rotating part (6) is the second area, and the ratio range of the first area to the second area is one-fifth to one-third.

3. The position-limiting device according to claim 1, wherein The steering shaft assembly (100) includes a steering shaft (4) and a steering shaft guide post (14), and the steering shaft (4) and the steering shaft guide post (14) are of an integrally formed structure; One end of the steering shaft (4) is connected to the steering wheel, and the steering shaft guide post (14) is arranged at the other end of the steering shaft (4).

4. The position-limiting device according to claim 3, characterized in that, The limiting end face includes a first limiting face (9) and a second limiting face (12), the first limiting face (9) is one side surface of the steering shaft (4) close to the rotating part (6), and the second limiting face (12) is one side surface of the limiting part (7) away from the rotating part (6); on the rotating part (6), one side surface close to the first limiting face (9) is the first surface (10), and the side surface away from the first limiting face (9) is the second surface (11); When the first surface (10) contacts the first limiting face (9), or the second surface (11) contacts the second limiting face (12), the steering wheel stops rotating, thereby realizing angle limitation of the steering wheel.

5. The limiting device according to claim 3, characterized in that, A rotating part guide groove (13) is arranged on the rotating part (6); The steering shaft guide post (14) passes through the rotating part (6) through the rotating part guide groove (13), and the steering shaft guide post (14) is in clearance fit with the rotating part guide groove (13); The outer surface of the steering shaft guide post (14) and the inner surface of the rotating part guide groove (13) are both arc-shaped.

6. The limit device according to claim 1, wherein The limiting device further includes a fixed base, and the rotating shaft assembly is arranged in the fixed base; The fixed base includes a housing (1), a bearing (2) and a snap ring (3), and a snap ring groove for cooperating with the snap ring (3) is further arranged on the housing (1); The assembly manner of the bearing (2) and the housing (1) is interference fit, and the snap ring (3) is arranged in the snap ring groove to fix the bearing (2).

7. The limit device according to claim 6, characterized in that The steering shaft assembly (100) further includes a hexagon nut (5); The steering shaft (4) has a clearance fit with the inner ring of the bearing (2), and the hexagon nut (5) is used to fix the steering shaft (4) to limit the radial freedom and axial freedom of the steering shaft (4).

8. The limiting device according to claim 6, characterized in that The limiting assembly further includes a plurality of bolts (8), a plurality of fixing holes (17) are arranged on the limiting part (7), and a plurality of limiting part threaded holes are further arranged on the housing (1); The plurality of bolts (8) pass through the plurality of fixing holes (17) and the plurality of limiting part threaded holes to fix the limiting part (7) to the housing (1), and the end face of the limiting part (7) is in contact with the end face of the housing (1).

9. The position-limiting device according to claim 1, characterized in that, The rotating part (6) and the limiting part (7) are made of alloy structural steel, and the alloy structural steel is subjected to quenching and tempering treatment and carburizing treatment.

10. A steer-by-wire system, characterized in that, Comprising the limiting device according to any one of claims 1-9.

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