An electric drive-by-wire steering system based on T-shaped screw rod and planetary reducer

Abstract

A kind of electric drive steer-by-wire system based on T type screw rod and planetary reducer, including steering driving device, steering knuckle arm, steering drag link and wheel assembly, two ends of steering knuckle arm are connected wheel assembly by steering drag link respectively, steering driving device includes steering driving motor, planetary reducer and T type screw rod mechanism, the output shaft of steering driving motor is connected planetary reducer, the planetary carrier output shaft of planetary reducer is connected output gear, T type screw rod mechanism includes left end cover, right end cover, T type screw rod and T type nut gear, left end cover is fixedly connected with right end cover and forms containing cavity, T type nut gear is installed in containing cavity, output gear is engaged with T type nut gear, T type nut gear is connected T type screw rod in thread hole, T type screw rod is connected with the third end of steering knuckle arm by connecting rod.This application not only can provide larger steering driving power, be applicable to larger tonnage vehicle;And save chassis layout space, reduce the mass of whole vehicle, reduce cost.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electric drive-by-wire steering systems for new energy vehicles, and more particularly to an electric drive-by-wire steering system based on a T-shaped screw rod and a planetary reducer. BACKGROUND

[0002] In recent years, the industry has gradually paid attention to the line control intelligent chassis of new energy scooters. As a key module of the vehicle chassis, the structure and function of the steering system are directly related to the reliability of the vehicle chassis. At present, the steering system mainly includes a traditional hydraulic steering mechanism and a rack-and-pinion steering mechanism. Among them, the hydraulic steering mechanism has a large volume and high cost, and has been abandoned by many new energy vehicle enterprises; the rack-and-pinion steering mechanism has a low load-carrying capacity and cannot be applied to large-tonnage vehicles, and the development cost is extremely high, which is not suitable for commercial vehicles.

[0003] In addition, the existing line control steering mechanism cannot lock the steering mechanism when there is no steering demand, which causes the steering mechanism to be easily affected by the impact of the ground on the wheels and mechanical failure; and the steering angle of the wheels cannot be limited, which easily causes vehicle failure and accidents due to over-steering. SUMMARY

[0004] The present application provides an electric drive-by-wire steering system based on a T-shaped screw rod and a planetary reducer, which mainly aims to overcome the shortcomings of the existing line control steering system, such as low load-carrying capacity and inability to be applied to large-tonnage vehicles.

[0005] The present application adopts the following technical solutions:

[0006] The utility model provides a kind of electric drive steer-by-wire system based on T screw rod and planetary reducer, including steering driving device, steering knuckle arm, steering tie rod and wheel assembly, the two ends of symmetry of steering knuckle arm are connected one wheel assembly respectively by a steering tie rod, steering driving device is connected with the third end of steering knuckle arm by a connecting rod to promote steering knuckle arm swing, to make two steering tie rod pull corresponding wheel assembly rotate, steering driving device includes steering driving motor, planetary reduction power and T screw rod mechanism, the output shaft of steering driving motor is connected planetary reducer, the planetary carrier output shaft of planetary reducer is connected an output gear, T screw rod mechanism includes left end cap, right end cap, T screw rod and T nut gear, the left end cap is mounted on the vehicle frame, the left end cap is fixedly connected with the right end cap and forms a containing cavity, the right end cap is fixedly connected with the planetary reducer, the T nut gear is rotatably mounted in the containing cavity by bearing, the output gear is meshingly connected with the T nut gear, the threaded hole of the T nut gear is also connected with a T screw rod, the two ends of the T screw rod are respectively corresponding to pass out the left end cap and the right end cap, one end is connected with the third end of the steering knuckle arm by the connecting rod.

[0007] In a preferred embodiment, the outer side of the above-mentioned T nut gear is also provided with an electromagnetic clutch, which is mounted inside the left end cap by bolts, and the friction plate of the electromagnetic clutch is mounted on the T nut gear by a key.

[0008] In a preferred embodiment, the left end cap is provided with a through hole, and the T screw rod includes a connecting rod connecting section and a threaded connecting section, wherein one end of the connecting rod connecting section passes through the through hole, the other end is butt-jointed with the threaded connecting section, and a limiting step surface is formed, the outer diameter of the limiting step surface is larger than the inner diameter of the through hole, and when the T screw rod moves to the left side to make the wheel assembly reach the left turning limit, the limiting step surface abuts against the inner side wall of the through hole.

[0009] In a preferred embodiment, an enlarged limiting block is arranged at the connection between the connecting rod connecting section of the T screw rod and the connecting rod, and when the T screw rod moves to the right side to make the wheel assembly reach the right turning limit, the enlarged limiting block abuts against the outer side wall of the through hole.

[0010] In a preferred embodiment, the planetary reducer includes a planetary reducer housing, a sun gear, a planet gear, a ring gear and a planetary carrier output shaft, the planetary reducer housing is fixedly connected with the right end cap by bolts, the output shaft of the steering driving motor is connected with the sun gear by spline or shaft coupling, the sun gear is meshingly connected with a plurality of planet gears on the outside, a plurality of planet gears are meshingly connected with the inner side of the ring gear, and the central shafts of a plurality of planet gears are fixedly connected with the planetary carrier output shaft.

[0011] In a preferred embodiment, a plurality of bearings, an output gear and a lock nut are sequentially arranged on the output shaft of the planetary carrier, and the outer ring of the bearings is fixed to the right end cover.

[0012] In a preferred embodiment, the left end cover and the right end cover corresponding to the two ends of the T-shaped nut gear are respectively provided with a left mounting groove and a right mounting groove, a bearing is mounted at the opening of the left mounting groove and the right mounting groove respectively, and the two ends of the T-shaped nut gear are respectively fixed to the inner rings of the two bearings.

[0013] In a preferred embodiment, a rotation angle position sensor is further mounted on the rotation center point of the knuckle arm.

[0014] From the above description of the structure of the present application, compared with the prior art, the present application has the following advantages:

[0015] 1. The present application uses a steering drive motor equipped with a planetary reducer and a T-shaped screw mechanism as a steering drive power, the T-shaped screw is connected to the knuckle arm through a connecting rod to push the knuckle arm to swing, so that the two steering tie rods pull the corresponding wheel assembly to rotate. Not only can provide larger steering drive power, suitable for larger tonnage vehicle; but also can save chassis layout space, reduce the overall vehicle quality, reduce the cost. At the same time, the configuration of electric drive steering is easy to realize product platformization, which can be applied to various vehicle models.

[0016] 2. The outer side of the T-shaped nut gear of the present application is provided with an electromagnetic clutch, so that the T-shaped screw mechanism has self-locking function, which can cope with the impact problem of the ground to the wheel, reduce the mechanical failure rate under the line control mode, and the reliability is guaranteed.

[0017] 3. The present application uses mechanical structure and electromagnetic clutch to work together, has left and right limit rotation angle limiting and steering mid-position limiting function, and has software control and mechanical limiting safety redundancy design in steering function. And the electromagnetic clutch is arranged in the T-shaped screw mechanism, the working environment is good, and the electromagnetic clutch technology is mature at present, which further improves the reliability of the product. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 It is a front view of the present application.

[0019] Figure 2 It is a top view of the present application.

[0020] Figure 3 It is a sectional view of the steering drive device of the present application.

[0021] Figure 4 It is a structure diagram of the present application steering system reaching the left turning limit rotation angle.

[0022] Figure 5 Structure diagram of the present application turning system reaching the right turning limit angle. DETAILED DESCRIPTION

[0023] The specific embodiments of the present application will be described below with reference to the drawings. In order to fully understand the present application, many details are described below, but the present application can be implemented without these details for those skilled in the art. For well-known components, methods and processes, the following will not be described in detail.

[0024] An electric drive-by-wire steering system based on a T-type screw rod and a planetary reducer, referring to Figure 1 and Figure 2 , comprising a steering driving device 10, a steering knuckle arm 20, a steering tie rod 30 and a wheel assembly 40. The steering knuckle arm 20 is an isosceles triangle or a similar isosceles triangle structure, and the two symmetrical ends of the steering knuckle arm 20 are respectively hinged to a wheel assembly 40 through a steering tie rod 30. The steering driving device 10 is hinged to the third end of the steering knuckle arm 20 through a connecting rod 101 to push the steering knuckle arm 20 to swing, so that the two steering tie rods 30 pull the corresponding wheel assemblies 40 to rotate.

[0025] Referring to Figures 1 to 3 , the steering driving device 10 comprises a steering driving motor 11, a planetary reducer 12 and a T-type screw rod mechanism 13, the planetary reducer 12 comprises a planetary reducer shell 121, a sun gear 122, a planetary gear 123, a ring gear 124 and a planetary carrier output shaft 125, the output shaft of the steering driving motor 11 is connected with the sun gear 122 through a spline or a shaft coupling, the outer side of the sun gear 122 is connected with a plurality of planetary gears 123 in meshing, a plurality of planetary gears 123 are connected with the inner side of the ring gear 124 in meshing, and the central shafts of a plurality of planetary gears 123 are fixedly connected with the planetary carrier output shaft 125.

[0026] Referring to Figure 3 , the T-type screw rod mechanism 13 comprises a left end cover 131, a right end cover 132, a T-type screw rod 133 and a T-type nut gear 134, the left end cover 131 is installed on the vehicle frame 1, the left end cover 131 is fixedly connected with the right end cover 132 and forms a containing cavity, and the right end cover 132 is fixedly connected with the planetary reducer shell 121 through bolts.

[0027] Referring to Figure 3 , a plurality of first bearings 126, an output gear 127 and a locking nut 128 are sequentially arranged on the planetary carrier output shaft 125, the outer ring of the first bearing 126 is fixed on the right end cover 132, and the locking nut 128 is locked at the end of the planetary carrier output shaft 125 to prevent the output gear 127 from falling out.

[0028] Referring toFigure 3 The output gear 127 is located in the accommodating cavity, and the output gear 127 is engaged with a T-shaped nut gear 134. The left end cover 131 and the right end cover 132 are respectively provided with a left mounting groove 1311 and a right mounting groove 1321, and a second bearing 135 is mounted at the opening of the left mounting groove and the right mounting groove, respectively. The two ends of the T-shaped nut gear 134 are respectively correspondingly fixed to the inner rings of the two second bearings 135.

[0029] Referring to Figure 3 The T-shaped nut gear 134 is further connected with a T-shaped screw rod 133, and the two ends of the T-shaped screw rod 133 are correspondingly arranged to pass through the left end cover 131 and the right end cover 132, respectively. One end of the T-shaped screw rod 133 is connected with the third end of the knuckle arm 20 through the connecting rod 101.

[0030] Referring to Figure 3 The outer side of the T-shaped nut gear 134 is further provided with an electromagnetic clutch 136, and the electromagnetic clutch 136 is mounted in the left end cover 131 through bolts. The friction plate of the electromagnetic clutch 136 is mounted on the T-shaped nut gear 134 through a key. The on-off of the electromagnetic clutch 136 can control the rotation and stop of the T-shaped nut gear 134, so as to control the locking and unlocking of the steering.

[0031] Referring to Figure 3 and Figure 4 The left end cover 131 is provided with a through hole 1312, and the T-shaped screw rod 133 includes a connecting rod connecting section 1331 and a threaded connecting section 1332. One end of the connecting rod connecting section 1331 passes through the through hole 1312, and the other end is butted with the threaded connecting section 1332, and a limiting step surface 1333 is formed. The outer diameter of the limiting step surface 1333 is greater than the inner diameter of the through hole 1312. When the T-shaped screw rod 133 moves to the left to make the wheel assembly 40 reach the left turning limit, the software control fails to identify, and the steering drive motor continues to operate. At this time, the limiting step surface 1333 of the T-shaped screw rod abuts against the inner side wall of the through hole 1312, so as to limit the steering system to continue to turn to the left, and avoid over-steering to cause vehicle failure and accidents.

[0032] Referring to Figure 3 The rotation center point of the knuckle arm 20 is further provided with a rotation angle position sensor 21. When the vehicle travels in a straight line, the rotation angle of the electric drive-by-wire steering system is in the middle position, and the position information can be obtained through the rotation angle position sensor 21. The steering drive motor 11 stops working, and the electromagnetic clutch 136 located on the T-shaped nut gear 134 is closed, so as to limit the rotation of the T-shaped nut gear 134, and thus the electric drive-by-wire steering system stops rotating. Therefore, the T-shaped screw rod mechanism has a self-locking function, and even the impact force of the ground on the wheels cannot cause the wheels to steer, so as to ensure the vehicle to travel in a straight line.

[0033] Referring to Figure 3 and Figure 5 The connecting section 1331 of the T-shaped screw rod 133 is provided with an enlarged limiting block 102 at the connecting position with the connecting rod 101. When the T-shaped screw rod 133 moves to the right to reach the right turning limit of the wheel assembly 40, if the software control fails to recognize, the motor continues to run, at this time, the enlarged limiting block 102 at the connecting position of the connecting section 1331 of the T-shaped screw rod 133 and the connecting rod 101 abuts against the outer side wall of the through hole 1312, limiting the turning system to continue to turn right, avoiding over turning to cause vehicle failure and accident.

[0034] In addition, the corner position sensor 21 of the present application can also avoid the problem that the transmission gap of the deceleration mechanism can cause corner error, and can accurately identify the actual corner position of the steering mechanism. By processing the corner position sensor 21 signal of the steering mechanism and the sensor signal of the steering wheel, the steering intention of the driver is identified, so as to control the steering mechanism to perform corresponding action.

[0035] The above is only a specific embodiment of the present application, but the design concept of the present application is not limited thereto, and any non-essential modification of the present application using this concept shall be deemed as an infringement of the protection scope of the present application.

Claims

1. An electrically driven steer-by-wire system based on a T-type lead screw and a planetary reducer, characterized by: The steering wheel assembly comprises a steering drive device, a steering knuckle arm, a steering tie rod and a wheel side assembly, wherein the symmetrical two ends of the steering knuckle arm are respectively connected to one of the wheel side assemblies through a steering tie rod, and the steering drive device is connected to the third end of the steering knuckle arm through a connecting rod to push the steering knuckle arm to swing, so that the two steering tie rods pull the corresponding wheel side assemblies to rotate, and the steering drive device comprises a steering drive motor, a planetary reducer and a T-type screw mechanism, the output shaft of the steering drive motor is connected to the planetary reducer, the planetary carrier output shaft of the planetary reducer is connected to an output gear, and the T-type screw mechanism comprises a left end cover, a right end cover, a T-type screw and a T-type nut gear, the left end cover is mounted on the vehicle frame, the left end cover is fixedly connected to the right end cover and forms an accommodating cavity, the right end cover is fixedly connected to the planetary reducer, the T-type nut gear is rotatably mounted in the accommodating cavity through a bearing, the output gear is meshed with the T-type nut gear, and the threaded hole of the T-type nut gear is also connected A T-shaped screw rod, the two ends of which pass through the left end cover and the right end cover respectively, one end of which is connected to the third end of the steering knuckle arm through the connecting rod; an electromagnetic clutch is also installed on the outside of the T-shaped nut gear, and the electromagnetic clutch is installed inside the left end cover by bolts, and the friction plate of the electromagnetic clutch is installed on the T-shaped nut gear by a key; the left end cover is provided with a through hole, and the T-shaped screw rod includes a connecting rod connecting section and a threaded connecting section, wherein the connecting rod connecting section One end passes through the through hole, and the other end is connected to the threaded connection section to form a limiting step surface. The outer diameter of the limiting step surface is larger than the inner diameter of the through hole. When the T-type screw moves to the left so that the wheel side assembly reaches the left turn limit, the limiting step surface abuts against the inner wall of the through hole; an enlarged limiting block is provided at the connection between the connecting rod connection section of the T-type screw and the connecting rod. When the T-type screw moves to the right so that the wheel side assembly reaches the right turn limit, the enlarged limiting block abuts against the outer wall of the through hole.

2. The electrically driven steer-by-wire system based on a T-type lead screw and a planetary reducer according to claim 1, characterized in that: The planetary reducer includes a planetary reducer housing, a sun gear, planetary gears, a ring gear and a planetary carrier output shaft. The planetary reducer housing is fixedly connected to the right end cover by bolts. The output shaft of the steering drive motor is connected to the sun gear through a spline or a coupling. The outer side of the sun gear is meshed with several planetary gears, and several planetary gears are meshed with the inner side of the ring gear. The center axes of several planetary gears are fixedly connected to the planetary carrier output shaft.

3. The electrically driven steer-by-wire system based on a T-type lead screw and a planetary reducer according to claim 2, characterized in that: A plurality of bearings, an output gear and a locking nut are sequentially mounted on the output shaft of the planetary carrier, and the outer ring of the bearing is fixed on the right end cover.

4. The electrically driven steer-by-wire system based on a T-type lead screw and a planetary reducer according to claim 1, characterized in that: The left end cover and the right end cover corresponding to the two ends of the T-nut gear are respectively provided with a left mounting groove and a right mounting groove, and a bearing is respectively installed at the opening of the left mounting groove and the right mounting groove. The two ends of the T-nut gear are respectively fixed to the inner rings of the two bearings.

5. The electrically driven steer-by-wire system based on a T-type lead screw and a planetary reducer according to claim 1, characterized in that: A rotation angle position sensor is also installed on the rotation center point of the steering knuckle arm.

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