CN218198476U

CN218198476U - Pure electric power-assisted steering gear for commercial heavy truck

Info

Publication number: CN218198476U
Application number: CN202222605095.2U
Authority: CN
Inventors: 李付兵; 杨志才; 许斌; 周祺; 王晓斌
Original assignee: SHAANXI WANFANG AUTO PARTS CO Ltd
Current assignee: Shaanxi Dezhen Component Technology Co ltd
Priority date: 2022-09-30
Filing date: 2022-09-30
Publication date: 2023-01-03
Anticipated expiration: 2032-09-30

Abstract

The utility model belongs to the technical field of the automobile manufacturing, a pure electric power assisted steering ware that commercial heavy truck used, including casing, input shaft, torsion bar, moment of torsion corner sensor, first motor, second motor, screw rod outer nut, spur rack, sector gear, rocking arm axle, moment of torsion corner sensor response driver's steering dynamics and angle, the motor passes through the worm gear, the screw rod passes through planet roller lead screw, the outer nut of screw rod passes through gear rack tertiary speed reduction torque increase mechanism after with helping hand moment of torsion to the rocking arm axle; the utility model discloses on the basis that does not change whole car and turn to installation and overall structure, realized that pure electric of heavy truck turns to, because the utility model discloses a bi-motor power mode can effectively share and turn to power, realizes the conventional function that turns to the motor, has effectively eliminated the not enough problem of motor power, the not enough problem of worm gear intensity, the not enough problem of ball screw intensity.

Description

Pure electric power-assisted steering gear for commercial heavy truck

Technical Field

The utility model belongs to the technical field of the automobile manufacturing, a pure electric power assisted steering ware that commercial heavy truck used.

Background

The electric power steering technology of commercial vehicles is gradually rising, the mainstream structure of the commercial vehicles still is a pure hydraulic circulating ball structure at present, and meanwhile, the electric mechanical circulating ball structure and the electric hydraulic circulating ball structure which can realize advanced functions are rising in recent years. The electromechanical recirculating ball steering gear is mainly used for light trucks, and cannot be applied to medium-heavy trucks due to the problems of mechanical strength, motor power and the like. In the aspect of electric steering, the medium-weight truck develops an electro-hydraulic steering mode combining a traditional hydraulic steering device and an electric unit, and mainstream manufacturers consider the electro-hydraulic steering mode as a transition scheme. The new high-torque pure electric steering also becomes the focus of the industry. Each manufacturer continues to exert force on the electric steering of the medium and heavy truck.

The existing pure hydraulic steering gear, electric mechanical circulating ball steering gear and electric hydraulic steering gear all have different defects, which are as follows:

pure hydraulic steering gear: use traditional hydraulic pressure as power assisted steering, provide power by the engine, the product all need last consumption engine power when turning to with not turning to, and has the noise big, oil leak risk scheduling problem, still need increase the electric pump and satisfy the power assisted steering requirement at present on pure electric commercial vehicle, increase whole car cost.

Electromechanical recirculating ball steering gear: the electric mechanical circulating ball steering gear is a newly developed pure electric steering gear, the power of the circulating ball steering gear is large, a bearing capacity component is a pure mechanical structure, a ball screw is accompanied with fluidity due to low friction force, and steel ball point contact causes poor bearing capacity, so that the electric mechanical circulating ball steering gear can only be used for outputting below 1500N.m at present, can only be applied to light trucks in small scale, cannot meet heavy-load requirements of medium trucks, heavy trucks and the like, and restricts the pure electric development of commercial vehicle steering gears due to the limitation of the bearing capacity.

An electro-hydraulic steering gear: the electric hydraulic steering gear is a compromise scheme for meeting the electric control steering requirement of a medium-weight truck and ensuring the mechanical strength of a product, keeps the power-assisted characteristic of the hydraulic steering gear, increases a control part of the electric steering, but has the cost nearly doubled compared with that of the original hydraulic steering gear because of belonging to two system integration schemes, and also keeps the characteristics of the hydraulic steering gear, such as high noise, high power consumption, oil leakage and the like, so that the electric hydraulic steering gear cannot be really popularized on commercial vehicles.

How to realize the pure electric steering of the medium and heavy truck commercial vehicle becomes the urgent need of the current commercial vehicle steering. The research on a pure electric steering gear with large torque and high bearing capacity is a necessary way for the development of steering electromotion of a commercial vehicle. Therefore, a new pure electric power steering apparatus is urgently needed to solve the above problems.

SUMMERY OF THE UTILITY MODEL

The utility model provides a technical scheme that technical problem took is: a pure electric power steering gear for a commercial heavy truck comprising: the device comprises a shell, an input shaft, a torsion bar, a torque angle sensor, a first motor, a second motor, a screw nut, a spur rack, a sector gear and a rocker shaft;

one end of the input shaft extends into the shell, one end of the input shaft, which is positioned outside the shell, is connected with a steering column of the whole vehicle and synchronously rotates, one end of the input shaft, which is positioned inside the shell, is coaxially and fixedly connected with the upper end of a torsion bar, the lower end of the torsion bar is coaxially and fixedly connected with the upper end of a screw, an outer nut of the screw is sleeved outside the screw, a spur rack is vertically arranged on the outer circumference of the outer nut of the screw, the spur rack is meshed with a sector gear, a rocker shaft which coaxially and synchronously rotates is arranged at a rotating shaft of the sector gear, the output end of the rocker shaft extends out of the shell, and the output end of the rocker shaft is used for assisting to drive the vehicle to steer;

the first motor and the second motor respectively transmit the motor power to the first worm wheel and the second worm wheel through the first worm and the second worm, and the first worm wheel and the second worm wheel are respectively sleeved and fixed on the outer circumference of the screw rod so that the worm wheel provides torque for the screw rod; the output power of the two sets of motor drives is superposed, so that the requirement of the heavy truck on the output force is ensured, and the requirement of the heavy truck on pure electric steering is met; meanwhile, two motors are provided with two control systems, a TAS sensor is a 4+2 redundant sensor, and an upper motor controller assembly and a lower motor controller assembly are adopted, so that redundant control can be realized, if a single motor fails, the full torque output of the other motor can ensure 50% of output force, the GB17675 requirement is met, and the running safety of the whole vehicle is ensured;

a stator of the torque angle sensor is fixedly connected with the outer circumference of the input shaft, a rotor of the torque angle sensor is fixedly connected with the outer circumference of the screw rod, the torque angle sensor is electrically connected to the vehicle-mounted ECU, the torque angle sensor outputs detected torque and angle electric signals to the vehicle-mounted ECU, the first motor and the second motor are respectively electrically connected to the vehicle-mounted ECU, and the vehicle-mounted ECU sends commands to control the motor currents of the first motor and the second motor so as to realize the rotation of the motors;

a roller is arranged between the screw and the screw outer nut, and the screw, the screw outer nut and the roller form a planetary roller screw structure; the planet roller screw is used as a steering gear transmission mechanism, under the same size, the bearing capacity of the planet roller screw can reach more than 3 times of that of the traditional ball screw, and the requirement of heavy truck on large output force can be met; meanwhile, the back of the screw nut is provided with a supporting structure, so that the bending moment borne by the screw rod is effectively counteracted, the bearing capacity is improved, the center distance of a product can be the same as that of the conventional hydraulic steering gear, and the structural change of the whole vehicle is avoided;

the two ends of the screw rod are rotatably connected with the inner wall of the shell through bearings.

Preferably, the first worm wheel and the second worm wheel are respectively sleeved at the upper end and the lower end of the screw rod.

Preferably, the first worm wheel and the second worm wheel are respectively sleeved on the outer sides of the bearings.

Preferably, a planetary roller screw structure formed by the screw, the screw outer nut and the roller is provided with an upper support positioning disc part, a lower support positioning disc part and an upper locking nut part, and the upper support positioning disc part, the lower support positioning disc part, the upper locking nut part and the lower locking nut part are sleeved on the screw to limit the stroke of the screw outer nut.

Preferably, the bearing is a tapered roller bearing, and the bearing is reversely and internally pressed at two ends of the screw rod.

Preferably, the shell is externally provided with five mounting holes for loading a steering gear.

The utility model has the advantages that:

the utility model discloses on the basis that does not change whole car and turn to installation and overall structure, realized that electricelectric that heavily blocks turns to, because the utility model discloses a bi-motor power mode can effectively share and turn to power, realizes the steering function of conventional steering motor, adopts planet roller screw as the transmission simultaneously, and its load transmission is the line contact, possesses the load impact ability and the stand wear and tear life-span of change, and the load can reach more than 3 times with specification ball screw. The whole structure effectively solves the problems of insufficient motor power, insufficient strength of the worm and the worm wheel and insufficient strength of the ball screw. Therefore, the main advantages are as follows: under the same size, the requirements of pure electric steering can be met, the problem of high power consumption of hydraulic steering is solved, and the problem of abnormal sound and oil leakage of the hydraulic steering is solved; by using the double-power-assisted system, the transmission ratio of 1 or 2 worm gears can be adjusted according to the requirement, the aim of adjusting the overall output force is fulfilled, and the steering output requirements of commercial vehicles with different loads and different working conditions can be met; the parts in the whole structure are processed by a mature process, so that the manufacturing cost is relatively low, and the electric steering device has more advantages than the electric steering device; the nut back supporting structure is adopted, so that the bending of the screw rod caused by load is effectively eliminated, the friction of a planetary roller screw structure is reduced, and the efficiency is effectively improved; the double-motor system also provides a redundancy protection function, and can realize 50% load output under the condition of single motor failure

Drawings

FIG. 1 is a schematic diagram of a pure electric power steering gear for a commercial heavy truck;

FIG. 2 is a left side sectional view;

fig. 3 is a rear sectional view.

In the figure: 1. a housing; 2. an input shaft; 3. a torsion bar; 4. a torsion rotation angle sensor; 5. a first motor; 6. a second motor; 7. a screw; 8. an outer nut of the screw rod; 9. straight rack; 10. a sector gear; 11. a rocker shaft; 12. a first worm; 13. a second worm; 14. a first worm gear; 15. a second worm gear; 16. a roller; 17. a bearing; 18. the positioning disc piece is supported up and down; 19. an upper and a lower locking nut members; 20. and (7) installing holes.

Detailed Description

The related art in the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is to be understood that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts all belong to the protection scope of the present invention.

Referring to fig. 1 to 3, a pure electric power steering gear for a commercial heavy truck includes: the device comprises a shell 1, an input shaft 2, a torsion bar 3, a torque angle sensor 4, a first motor 5, a second motor 6, a screw 7, a screw nut 8, a spur rack 9, a sector gear 10 and a rocker shaft 11;

one end of an input shaft 2 extends into the shell 1, one end of the input shaft 2, which is positioned outside the shell 1, is connected with a steering column of the whole vehicle and synchronously rotates, one end of the input shaft 2, which is positioned inside the shell 1, is coaxially and fixedly connected with the upper end of a torsion bar 3, the lower end of the torsion bar 3 is coaxially and fixedly connected with the upper end of a screw 7, an outer nut 8 of the screw is sleeved outside the screw 7, a spur rack 9 is vertically arranged on the outer circumference of the outer nut 8 of the screw, the spur rack 9 is meshed with a sector gear 10, a rocker shaft 11 which coaxially and synchronously rotates is arranged at a rotating shaft of the sector gear 10, the output end of the rocker shaft 11 extends out of the shell 1, and the output end of the rocker shaft 11 is used for assisting to drive the steering of the vehicle;

the first motor 5 and the second motor 6 respectively transmit the motor power to the first worm wheel 14 and the second worm wheel 15 through the first worm 12 and the second worm 13, and the first worm wheel 14 and the second worm wheel 15 are respectively sleeved and fixed on the outer circumference of the screw 7 so that the worm wheels provide torque for the screw 7; the output power of the two sets of motor drives is superposed, so that the requirement of the heavy truck on the output force is ensured, and the requirement of the heavy truck on pure electric steering is met; meanwhile, two sets of motors are provided with two sets of control systems, a TAS sensor is adopted as a 4+2 redundant sensor, and an upper set and a lower set of motor controller assemblies can realize redundant control, if a single motor fails, the full torque output of the other motor can ensure 50% output force, the GB17675 requirement is met, and the running safety of the whole vehicle is ensured;

a stator of the torque angle sensor 4 is fixedly connected with the outer circumference of the input shaft 2, a rotor of the torque angle sensor 4 is fixedly connected with the outer circumference of the screw 7, the torque angle sensor 4 is electrically connected to a vehicle-mounted ECU, the torque angle sensor 4 outputs detected torque and angle electric signals to the vehicle-mounted ECU, the first motor 5 and the second motor 6 are respectively electrically connected to the vehicle-mounted ECU, and the vehicle-mounted ECU sends commands to control motor currents of the first motor 5 and the second motor 6 to realize motor rotation;

a roller 16 is arranged between the screw 7 and the screw outer nut 8, and the screw 7, the screw outer nut 8 and the roller 16 jointly form a planetary roller screw structure; the planet roller screw is used as a steering gear transmission mechanism, under the same size, the bearing capacity of the planet roller screw can reach more than 3 times of that of the traditional ball screw, and the requirement of heavy truck on large output force can be met; meanwhile, the back of the screw nut is provided with a supporting structure, so that the bending moment borne by the screw rod is effectively offset, the bearing capacity is improved, the center distance of a product can be the same as that of the conventional hydraulic steering gear, and the structural change of the whole vehicle is avoided;

both ends of the screw 7 are rotatably connected to the inner wall of the housing 1 through bearings 17.

Further, the first worm wheel 14 and the second worm wheel 15 are respectively sleeved at the upper end and the lower end of the screw 7.

Furthermore, the first worm wheel 14 and the second worm wheel 15 are respectively sleeved on the outer sides of the bearings 17.

Furthermore, a planetary roller screw structure formed by the screw 7, the screw outer nut 8 and the roller 16 is provided with an upper and lower support positioning disc part 18 and an upper and lower locking nut part 19, and the upper and lower support positioning disc part 18 and the upper and lower locking nut part 19 are sleeved on the screw 7 to limit the stroke of the screw outer nut 8.

Further, the bearing 17 is a tapered roller bearing, and the bearing 17 is reversely and inwardly pressed at two ends of the screw 7.

Further, the housing 1 is provided with five mounting holes 20 at the outside for loading the steering gear.

Examples

In this embodiment, the implementation is performed according to a general steering scheme of the heavy truck, a traditional heavy truck 5-mounting-hole mode is adopted, the hydraulic system is completely removed, and the torsion angle sensor 4 is mounted at the input end and used for detecting the hand force and the steering angle of a driver and transmitting signals to the motor controllers at the upper end and the lower end. The motor is output and then is decelerated and torque-increased by a worm and gear speed reducing mechanism through a primary speed reducing mechanism, a first motor 5 and a second motor 6 are respectively arranged at the upper end and the lower end of a screw 7, two motor controllers synchronously receive signals of a torsion angle sensor 4 and receive information such as the torque, the angle, the speed and the like of the whole vehicle to control the two motors to rotate, the torque is superposed on secondary speed reduction through the speed reduction of the worm and gear, and the secondary speed reducing mechanism adopts a planetary roller screw structure to convert the circular motion into the linear motion of a screw nut 8. The three-stage speed reducing mechanism uses a gear-rack transmission mechanism with a spur rack 9 meshed with a sector gear 10, the spur rack 9 is processed on the outer circumference of a screw nut 8, and the linear motion of the screw nut 8 is converted into the rotary motion of a rocker arm shaft 11 again. The steering of the product is realized through three-level deceleration of the whole structure.

The working principle of the embodiment is as follows:

the input shaft 2 is connected with a whole vehicle steering column and transmits steering hand force of a driver, the driver transmits the steering hand force to the torsion bar 3 through the input shaft 2 in hand to realize relative rotation of the input shaft 2 and the screw 7, the stator of the torsion angle sensor 4 is installed on the input shaft 2, the rotor of the torsion angle sensor 4 is assembled on the screw 7, when the input shaft 2 and the screw 7 rotate relatively, the torsion angle sensor 4 detects a torque angle signal and transmits the signal to the first motor 5 and the second motor 6 through a wire harness, and the first motor 5 and the second motor 6 control motor current through an internal algorithm of an ECU (electronic control Unit), so that the motor rotation is realized.

After the motor rotates, power is transmitted to the pair of upper worm wheels 14 and the pair of lower worm wheels 15 through the pair of upper worm wheels 12 and the pair of lower worm wheels 13 respectively, the worm wheels are pressed on the screw 7, the power is transmitted to the screw 7, the rotary motion of the screw 7 is converted into the linear motion of the screw outer nut 8 through a planetary roller screw structure consisting of the screw 7, the roller 16, the screw outer nut 8, the upper and lower supporting and positioning disc part 18 and the upper and lower locking nut parts 19, the straight rack 9 is processed on the screw outer nut 8, the straight rack 9 and the sector gear 10 of the rocker arm shaft 11 form gear rack transmission, and the linear motion of the screw outer nut 8 is converted into the rotary motion of the rocker arm shaft 11, so that the integral power transmission is realized. The screw 7 is arranged in the shell 1 and supported by the locking nut components at the upper end and the lower end, the locking nut components are bearings 17, and the bearings 17 are tapered roller bearings which are pressed in.

The whole product has the following force transmission ratio:

i＝(i1+i2)*i3

wherein i1 is an upper worm gear speed reducing mechanism, and i2 is a lower worm gear speed reducing mechanism transmission ratio. i3 is the transmission ratio of the planet ball screw of the steering gear to the rack rocker shaft.

Wherein the transmission ratio of the i1 and the i2 worm gears is the number of worm gear teeth/the number of worm heads, and the current design range is 20-21; i3=2 π Rf/t, the pitch radius of the sector gear, t is the pitch of the ball screw, i3 is the ratio of the angle between the input end and the output end of the whole vehicle, which is generally adjusted within the range of 17-22.5, so that the maximum transmission ratio is about 21 × 22.5=945 at present.

According to the transmission ratio, 24V and 8N.m motors of the commercial vehicles are used, the maximum output force is T =8 x 945 x 0.75=5670N.m, then the hand force of the driver is superposed 10N.m, the output force is 10 x 22.5 x 0.8=180N.m, the maximum output force is 5850N.m, and the load-carrying requirements of most commercial vehicles can be met.

To sum up, the utility model provides a pure electric power assisted steering ware that commercial heavy truck used, on not changing the whole car and turning to installation and overall structure's basis, realized that the pure electric of heavy truck turns to, because the utility model discloses a bi-motor power mode can effectively share the power that turns to, realizes the conventional function that turns to the motor, adopts planet roller screw as the transmission simultaneously, and its load transmission is the line contact, possesses the load impact ability and the stand wear and tear life-span of change, and load can reach more than 3 times with specification ball screw. Overall structure has effectively eliminated the not enough problem of motor power, the not enough problem of worm gear intensity, the not enough problem of ball intensity, consequently the utility model discloses possess extensive application prospect.

It is to be emphasized that: the above embodiments are only preferred embodiments of the present invention, and are not intended to limit the present invention in any form, and any simple modifications, equivalent changes and modifications made by the technical spirit of the present invention to the above embodiments are all within the scope of the technical solution of the present invention.

Claims

1. The utility model provides a pure electric power assisted steering ware that commercial heavy truck used which characterized in that includes: the device comprises a shell (1), an input shaft (2), a torsion bar (3), a torque and rotation angle sensor (4), a first motor (5), a second motor (6), a screw (7), a screw outer nut (8), a spur rack (9), a sector gear (10) and a rocker shaft (11);

one end of the input shaft (2) extends into the shell (1), one end of the input shaft (2) positioned outside the shell (1) is connected with a whole vehicle steering column and synchronously rotates, one end of the input shaft (2) positioned inside the shell (1) is coaxially and fixedly connected with the upper end of the torsion bar (3), the lower end of the torsion bar (3) is coaxially and fixedly connected with the upper end of the screw (7), the screw (7) is sleeved with the outer nut (8) of the screw in an sleeved mode, the straight rack (9) is vertically arranged on the outer circumference of the outer nut (8) of the screw, the straight rack (9) is meshed with the sector gear (10), the rocker shaft (11) which coaxially and synchronously rotates is arranged at the rotating shaft of the sector gear (10), the output end of the rocker shaft (11) extends out of the shell (1), and the output end of the rocker shaft (11) is used for assisting in driving the steering of the vehicle;

the first motor (5) and the second motor (6) respectively transmit the motor power to the first worm wheel (14) and the second worm wheel (15) through the first worm (12) and the second worm (13), and the first worm wheel (14) and the second worm wheel (15) are respectively sleeved and fixed on the outer circumference of the screw rod (7) so that the worm wheels provide torque for the screw rod (7);

the stator of the torque and angle sensor (4) is fixedly connected with the outer circumference of the input shaft (2), the rotor of the torque and angle sensor (4) is fixedly connected with the outer circumference of the screw (7), the torque and angle sensor (4) is electrically connected to an on-board ECU (electronic control unit), the torque and angle sensor (4) outputs detected torque and angle electric signals to the on-board ECU, the first motor (5) and the second motor (6) are electrically connected to the on-board ECU respectively, and the on-board ECU sends commands to control the motor currents of the first motor (5) and the second motor (6) to realize the rotation of the motors;

a roller (16) is arranged between the screw (7) and the screw outer nut (8), and the screw (7), the screw outer nut (8) and the roller (16) jointly form a planetary roller screw structure;

and two ends of the screw rod (7) are rotatably connected with the inner wall of the shell (1) through a bearing (17).

2. The pure electric power-assisted steering gear for the commercial heavy truck according to claim 1, characterized in that the first worm wheel (14) and the second worm wheel (15) are respectively sleeved at the upper end and the lower end of the screw rod (7).

3. A pure electric power steering gear for commercial heavy truck according to claim 2, characterized in that the first worm gear (14) and the second worm gear (15) are respectively sleeved outside the bearing (17).

4. The pure electric power-assisted steering gear for the commercial heavy truck as claimed in claim 1, characterized in that the planetary roller screw structure formed by the screw (7), the screw outer nut (8) and the rollers (16) is provided with an upper and lower supporting positioning disc member (18) and an upper and lower locking nut member (19), and the upper and lower supporting positioning disc member (18) and the upper and lower locking nut member (19) are sleeved on the screw (7) to limit the stroke of the screw outer nut (8).

5. A pure electric power-assisted steering gear for a commercial heavy truck according to claim 1, characterized in that the bearing (17) is a tapered roller bearing, and the bearing (17) is pressed inwards in the opposite direction at the two ends of the screw (7).

6. A purely electric power steering gear for a commercial heavy truck according to claim 1, characterized in that the housing (1) is externally provided with five mounting holes (20) for loading the steering gear.