CN113715904A

CN113715904A - Electric power steering gear

Info

Publication number: CN113715904A
Application number: CN202111093753.8A
Authority: CN
Inventors: 郑竹安; 魏金呈; 张坤; 石小龙; 熊新; 翟豪瑞; 孙婷婷
Original assignee: Yancheng Institute of Technology
Current assignee: Hefei Jiuzhou Longteng Scientific And Technological Achievement Transformation Co ltd
Priority date: 2021-09-17
Filing date: 2021-09-17
Publication date: 2021-11-30
Anticipated expiration: 2041-09-17
Also published as: CN113715904B

Abstract

The invention discloses an electric power steering gear, which comprises a steering shaft and a power-assisted motor, wherein a double-worm driving assembly and a two-way transmission assembly are connected to the steering shaft, the output end of the power-assisted motor is connected with a speed reducing mechanism, the power-assisted motor is connected with a transmission shaft through the speed reducing mechanism, the two-way transmission assembly is connected with the transmission shaft and the double-worm driving assembly, the single worm is arranged into the double worm, and the transmission between two worm wheels and the steering shaft is changed through a ratchet mechanism, so that the single worm and worm wheel only rotate in one way, the idle rotation caused by the generation of a gap during the reverse rotation due to abrasion is effectively avoided, the response time effect of the steering is influenced, a detection part is arranged on the side of the ratchet mechanism, the detection part detects the relative rotation angle between the transmission shaft and a first gear, and the time for compensating the rotation angle of the power-assisted motor is determined, the travel time is shortened as much as possible, thereby improving the response timeliness.

Description

Electric power steering gear

Technical Field

The invention relates to the technical field of steering gears, in particular to an electric power steering gear.

Background

EPS is an abbreviation of Electric Power Steering in english. An electric power steering system is the development direction of an automobile steering system. The system directly provides steering power by the electric power-assisted machine, saves a power steering oil pump, a hose, hydraulic oil, a conveyor belt and a belt pulley arranged on an engine which are necessary for a hydraulic power steering system, saves energy and protects the environment. In addition, the steering assisting device has the characteristics of simple adjustment, flexible assembly and capability of providing steering assisting power under various conditions.

According to different installation positions of the power-assisted motors, the EPS system can be divided into 3 types of steering shaft power-assisted type, gear power-assisted type and rack power-assisted type, a torque sensor is arranged between a steering shaft and a steering wheel shaft, a torque corner sensor generates corresponding voltage signals according to input torque and steering angle, a vehicle speed sensor detects a vehicle speed signal, and a control unit (ECU) gives instructions to control the motor to operate according to the voltage and the vehicle speed signal, so that the required steering power is generated.

Because the steering of the wheels needs larger torque under the influence of the self weight of the vehicle, a speed reducing mechanism is arranged between the auxiliary motor and the steering shaft to increase the torque, the conventional gear speed reducing mechanism needs to change the transmission ratio of the gears, and a plurality of gears are overlapped when a large torque state is needed, so that the torque is increased by realizing a large speed reducing ratio through the worm gear, for example, a rocker arm shaft assisted type circulating ball electric power steering gear disclosed by Chinese patent publication No. CN112829825A uses the worm gear, but because the worm gear mainly depends on the friction transmission of the side surface of the worm gear and the spiral side surface of the worm gear, the abrasion is caused, namely, the clearance is arranged between the worm gear, if the transmission is only wanted transmission, the clearance cannot be influenced, but the steering of the wheels is bidirectional, when the steering is switched, the clearance can cause the idle rotation of the worm until the worm gear contacts the worm gear again to drive, because the steering wheel rotates to the wheels to steer, the steering action is delayed slightly due to the time required by the mechanical transmission and the corresponding time of the electrical components, the clearance between the worm and the worm wheel is further increased, and the delay is continuously increased along with the abrasion of the worm and the worm wheel, which is not beneficial to the operation of a vehicle owner. To this end, we propose an electric power steering gear.

Disclosure of Invention

The present invention is directed to an electric power steering apparatus with a twin-worm auxiliary steering to solve the problems of the background art mentioned above.

In order to achieve the purpose, the invention provides the following technical scheme: an electric power steering gear comprises a steering shaft and a power-assisted motor, wherein a double-worm driving assembly and a bidirectional transmission assembly are connected to the steering shaft, the output end of the power-assisted motor is connected with a speed reducing mechanism and a transmission shaft through the speed reducing mechanism, and the bidirectional transmission assembly is connected with the transmission shaft and the double-worm driving assembly;

the double-worm driving assembly comprises two groups of worm wheels, the two groups of worm wheels are in one-way transmission connection with the steering shaft through a ratchet mechanism, the transmission directions of the two groups of worm wheels and the steering shaft are opposite, the two groups of worm wheels are meshed with worms, the parameters of the two groups of worm wheels and the worm wheels are the same, and the spiral directions of the two groups of worms are opposite;

the bidirectional transmission assembly comprises two sets of first gears which are connected to the transmission shaft in a one-way rotating mode through a ratchet mechanism, the one-way transmission direction of the first gears is opposite to that of the second gears, and one end of the worm is fixedly connected with a second gear connected with the first gear.

Preferably, two sets of gear rings are sleeved between the two sets of worms together, gear teeth are arranged on the inner radial surface and the outer radial surface of each gear ring, the inner side and the outer side of each gear ring are respectively meshed with the first gear and the second gear, and the reference circle diameter ratio of the inner teeth and the outer teeth of the gear rings can influence the integral transmission ratio.

Preferably, a detection part is arranged between the transmission shaft and the first gear, the detection part is used for detecting a relative rotation angle between the transmission shaft and the first gear, and a detection part is also arranged between the steering shaft and the worm gear, because the ratchet mechanism has a gap, namely, the pawl is a process in the process of moving one ratchet to the other ratchet, when the power-assisted motor rotates reversely, the pawl is not contacted with the pawl at the first time, the idle time is also provided, and for a faster response, the gap value is detected by the detection part, so that the power-assisted motor can be driven after rapidly compensating the gap value.

Preferably, the detection part comprises a resistance ring fixed on one side of the first gear, the transmission shaft is fixedly connected with a first electrode plate connected with the resistance ring, one side of the resistance ring is further provided with a second electrode plate, and the second electrode plate is connected with a brush block connected with the resistance ring in a sliding manner.

Preferably, the two groups of first gears are helical gears, the first gears and the helical gears are symmetrically arranged along the median planes of the adjacent end surfaces of the first gears, the outer side teeth of the gear ring are arranged corresponding to the outer side teeth, and the helical gears are more stable relative to straight gear transmission.

Preferably, the worm gear is a non-full worm gear.

Preferably, one end of the electric brush block is provided with a protrusion, the electric brush block is attached to at least two surfaces of the resistance ring, the electric brush block is movably connected to the second electrode plate, and the moving direction is the normal direction of the attachment surface of the electric brush block and the resistance ring.

Preferably, the brush block has an L-shaped cross section.

Compared with the prior art, the invention has the beneficial effects that:

1. according to the steering mechanism, the single worm is arranged into the double worms, and the transmission between the two worm wheels and the steering shaft is changed through the ratchet mechanism, so that the single worm and worm wheel only rotate in a single direction, and the phenomenon that the response time efficiency of steering is influenced due to idling caused by gaps generated by abrasion in the process of reverse rotation is effectively avoided;

2. the detection part is arranged on the side of the ratchet mechanism and detects the relative rotation angle between the transmission shaft and the first gear, so that when the transmission shaft rotates along one direction, the relative rotation angle between the ratchet and the pawl in the other non-transmission ratchet mechanism is determined, the time for the power-assisted motor to rotate for making up the rotation angle is determined, and in the time, the power-assisted motor rotates at a high speed, the stroke time is shortened as much as possible, and the response timeliness is improved.

Drawings

FIG. 1 is a schematic view of the overall structure of the present invention;

FIG. 2 is an expanded view of the dual worm drive assembly and bi-directional transmission assembly of the present invention;

FIG. 3 is an enlarged view of the structure of area A in FIG. 2;

FIG. 4 is an enlarged view of the structure of the area B in FIG. 3;

FIG. 5 is a schematic structural view of a double worm;

fig. 6 is a schematic view of the ratchet mechanism and the first gear.

In the figure: 1-a steering shaft; 2-a power-assisted motor; 3-a double worm drive assembly; 4-a bidirectional transmission assembly; 5-a transmission shaft; 6-a worm gear; 7-a worm; 8-a first gear; 9-a second gear; 10-a toothed ring; 11-a detection section; 12-a resistance ring; 13-a first electrode sheet; 14-a second electrode sheet; 15-brush block.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1-6, the present invention provides a technical solution: an electric power steering gear comprises a steering shaft 1 and a power-assisted motor 2, wherein the steering shaft 1 is connected with a double-worm driving assembly 3 and a bidirectional transmission assembly 4, the output end of the power-assisted motor 2 is connected with a speed reducing mechanism (not shown), the speed reducing mechanism is used for reducing the rotating speed and outputting larger torque, the speed reducing mechanism adopts a planetary gear speed reducing mechanism and the like and is connected with a transmission shaft 5 through the speed reducing mechanism, and the bidirectional transmission assembly 4 is connected with the transmission shaft 5 and the double-worm driving assembly 3;

the double-worm driving assembly 3 comprises two groups of worm wheels 6, the two groups of worm wheels 6 are in one-way transmission connection with the steering shaft 1 through a ratchet mechanism, the transmission directions of the two groups of worm wheels 6 and the steering shaft 1 are opposite, the two groups of worm wheels 6 are meshed with worms 7, the worm wheels 6 and the steering shaft 1 are in one-way transmission, the directions of the two groups of worm wheels are opposite, so that the two worms 7 can independently control the rotation control in two directions, the parameters of the two groups of worm wheels 7 and the worm wheels 6 are the same, the spiral directions of the two groups of worm wheels 7 are opposite, and the parameters of the worm wheels 7 and the worm wheels 6 are the same so as to keep the same transmission ratio;

the bidirectional transmission assembly 4 comprises two sets of first gears 8 which are connected to the transmission shaft 5 in a unidirectional rotation mode through a ratchet mechanism, the unidirectional transmission directions of the two gears are opposite, one end of the worm 7 is fixedly connected with a second gear 9 connected with the first gear 8, and two different steering directions of the power-assisted motor 2 drive different worms.

The worm wheel 6 is a non-complete worm wheel 6, and the vehicle can be turned to a certain range without 360-degree rotation, so that the complete worm wheel 6 is not needed, the non-effective working area can be effectively reduced, and the occupied space volume is reduced.

Two sets of gear rings 10 are sleeved between the two sets of worms 7 together, gear teeth are arranged on the inner radial surface and the outer radial surface of each gear ring 10, the inner side and the outer side of each gear ring 10 are respectively meshed with a set of first gear 8 and a set of second gear 9, the two sets of first gears 8 are both helical gears which are symmetrically arranged along the middle planes of the adjacent end surfaces of the first gears, and the outer teeth of the gear rings 10 are arranged correspondingly to the outer teeth of the gear rings, because the helical gears have better stability relative to the transmission of straight gears, the reference circle diameter ratio of the inner teeth and the outer teeth of the gear rings can influence the integral transmission ratio, the mode arrangement can reduce the loss of torque, the mode of directly meshing the first gears 8 with the second gears 9 needs to consider the transmission ratio, if the reference circle diameter of the first gears 8 is larger than the reference circle diameter of the second gears 9, the torque can be reduced, and if the second gears 9 are too large, the distance between the shaft diameters of the two worms 7 can be increased, the gear ring 10 is arranged, the transmission ratio can be changed by the reference circle diameter of the inner and outer teeth of the gear ring 10, the reduction of the torque is reduced as much as possible, and the two worms 7 cannot be far away from each other, so that the occupied space is small.

A detection part 11 is arranged between the transmission shaft 5 and the first gear 8, the detection part 11 is used for detecting the relative rotation angle between the transmission shaft 5 and the first gear 8, the detection part 11 is also arranged between the steering shaft 1 and the worm wheel 6, because the wear surfaces of the worm 7 and the worm wheel 6 are contact surfaces and effective working surfaces, a gap is generated after the steering shaft 1 and the worm wheel 6 are used, when the steering shaft 1 and the worm wheel 6 rotate, the worm 7 does not contact the worm wheel 6 to idle, the response time is delayed, the ratchet wheel pushes against the ratchet wheel through the pawl to transmit, the working surfaces do not slide relatively, the abrasion can be avoided, the gap between the ratchet wheel and the pawl is fixed, namely the included angle between two adjacent ratchet wheels is fixed, the gap value of the single worm is transferred into the ratchet wheel mechanism through the ratchet wheel mechanism and the double worm, the gap generated by the ratchet wheel is fixed, the control is more convenient, and the detection part 11 is used for detecting the rotation of one first gear 8, the relative rotation angle between the ratchet teeth of the ratchet mechanism in the other first gear 8 and the pawl is detected by the detection part 11, the detection part 11 is connected with an ECU (electronic control unit) on the vehicle, the relative rotation angle is determined through the detection of the detection part 11, the power-assisted motor 2 is firstly driven quickly to make up the rotation angle quickly during steering, the idle running time is reduced to the maximum extent, and the transmission time of steering is shortened.

The detection part 11 comprises a resistance ring 12 fixed on one side of the first gear 8, a first electrode plate 13 connected with the resistance ring 12 is fixedly connected to the transmission shaft 5, a second electrode plate 14 is further arranged on one side of the resistance ring 12, the two electrode plates 14 are respectively connected with two ends of the detection part, the lengths of the sections, which are connected with the resistance ring 12, are different along with the rotation of the two electrode plates driven by the first gear 8 or the transmission shaft 5, so that the relative rotation angle is detected by measuring the current, a brush block 15 connected with the resistance ring 12 in a sliding connection mode is connected to the second electrode plate 14, friction is generated due to rotation, and therefore wear-resistant and conductive materials are needed, the brush block 15 is made of the same material as a motor brush, and the conductivity is high and wear-resistant.

One end of the electric brush block 15 has a protrusion, and the electric brush block 15 is laminated with the two sides of the resistance ring 12 at least, the cross-section of the electric brush block 15 is L-shaped, the electric brush block 15 can be movably connected to the second electrode plate 14, the moving direction is the normal direction of the electric brush block 15 and the resistance ring 12, specifically, the electric brush block is elastically arranged on the second electrode plate 14, the normal movement of the two attachment surfaces is convenient for compensating the electric brush block through the elastic piece arranged after being worn, the state of the electric brush block is always kept, the second electrode plate 14 can be also arranged to be movable, the movement of the two directions is prevented from being concentrated on the electric brush block 15, and the structure is crowded.

It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims

1. An electric power steering device comprises a steering shaft (1) and a power motor (2), and is characterized in that: the steering shaft (1) is connected with a double-worm driving assembly (3) and a bidirectional transmission assembly (4), the output end of the power-assisted motor (2) is connected with a speed reducing mechanism and is connected with a transmission shaft (5) through the speed reducing mechanism, and the bidirectional transmission assembly (4) is connected with the transmission shaft (5) and the double-worm driving assembly (3);

the double-worm driving assembly (3) comprises two groups of worm wheels (6), the two groups of worm wheels (6) are in one-way transmission connection with the steering shaft (1) through a ratchet mechanism, the transmission directions between the two groups of worm wheels (6) and the steering shaft (1) are opposite, worms (7) are meshed on the two groups of worm wheels (6), the parameters of the two groups of worms (7) and the worm wheels (6) are the same, and the spiral directions of the two groups of worms (7) are opposite;

the bidirectional transmission assembly (4) comprises two sets of first gears (8) which are connected to the transmission shaft (5) in a one-way rotating mode through a ratchet mechanism, the directions of the two one-way transmissions are opposite, and one end of the worm (7) is fixedly connected with a second gear (9) connected with the first gear (8).

2. An electric power steering apparatus according to claim 1, wherein: two sets of jointly the cover is equipped with two sets of rings of teeth (10) between worm (7), the inside and outside radial surface of ring of teeth (10) all is equipped with the gear tooth, every group the inside and outside of ring of teeth (10) meshes with a set of first gear (8) and second gear (9) respectively.

3. An electric power steering apparatus according to claim 2, wherein: be equipped with detection portion (11) between transmission shaft (5) and first gear (8), detection portion (11) are used for detecting the relative rotation angle between transmission shaft (5) and first gear (8), be equipped with detection portion (11) between steering shaft (1) and worm wheel (6) equally.

4. An electric power steering apparatus according to claim 3, wherein: the detection part (11) comprises a resistance ring (12) fixed on one side of the first gear (8), a first electrode plate (13) connected with the resistance ring (12) is fixedly connected to the transmission shaft (5), a second electrode plate (14) is further arranged on one side of the resistance ring (12), and an electric brush block (15) connected with the resistance ring (12) in a sliding mode is connected to the second electrode plate (14).

5. An electric power steering apparatus according to claim 1, wherein: the two groups of first gears (8) are helical gears, the helical gears are symmetrically arranged along the middle planes of the adjacent end surfaces of the first gears, and the outer side teeth of the gear ring (10) are arranged corresponding to the outer side teeth.

6. An electric power steering apparatus according to claim 1, wherein: the worm wheel (6) is a non-complete worm wheel (6).

7. An electric power steering apparatus according to claim 4, wherein: the one end of brush piece (15) has the protrusion, and brush piece (15) at least with the two-sided laminating of resistance ring (12), brush piece (15) swing joint is on second electrode slice (14), and the activity direction is the normal direction of brush piece (15) and resistance ring (12) binding face.

8. An electric power steering according to claim 4 or 7, wherein: the cross section of the electric brush block (15) is L-shaped.