Active steering system using planetary gear set with less tooth difference and control method thereof

Patent metadata

Field	Value
Publication number	US-11186309-B2
Application number	US-201916383512-A
Country	US
Kind code	B2
Filing date	Apr 12, 2019
Priority date	May 17, 2018
Publication date	Nov 30, 2021
Grant date	Nov 30, 2021

Abstract

An active steering system using planetary gear set with less tooth difference and a control method thereof. The system includes a first input shaft with one end connected to a steering wheel of an automobile and the other end fixedly sleeved with a first gear; a ring gear sleeve, where a ring gear is fixedly mounted in the ring gear sleeve circumferentially, and a hollow shaft protrudes from a center of an end of the ring gear sleeve and is fixedly sleeved with a second gear engaged with the first gear; a second input shaft with one end fixedly connected to an output end of a coupled motor and the other end fixedly sleeved with a third gear; an eccentric shaft with one end fixedly sleeved with a fourth gear engaged with the third gear and the other end sleeved in the hollow shaft and eccentrically provided with a boss.

First claim

What is claimed is:

1. An active steering system using planetary gear set with less tooth difference, comprising:
a first input shaft, wherein one end of the first input shaft is connected to a steering wheel of an automobile, and the other end of the first input shaft is fixedly sleeved with a first gear;
a ring gear sleeve, wherein a ring gear is fixedly mounted in the ring gear sleeve in a circumferential direction, and a hollow shaft protrudes from a center of an end of the ring gear sleeve and is fixedly sleeved with a second gear that is engageable with the first gear;
a second input shaft, wherein one end of the second input shaft is fixedly connected to an output end of a coupled motor, and the other end of the second input shaft is fixedly sleeved with a third gear;
an eccentric shaft, wherein one end of the eccentric shaft is fixedly sleeved with a fourth gear that is engageable with the third gear, and the other end of the eccentric shaft is sleeved in the hollow shaft;
a planetary gear engaging with and rotating relative to the ring gear, wherein the planetary gear is provided with a plurality of first pin holes spaced apart in a circumferential direction; the eccentric shaft is eccentrically provided with a boss engaged with a center bore of the planetary gear in a clearance fit;
a plurality of pins each including a first journal, a second journal and a third journal, wherein the first journal is arranged to be eccentric to the second journal, the second journal is arranged to be concentric to the third journal, and the first journal is engaged with one of the plurality of the first pin holes in a clearance fit; and
an output shaft disc provided with a plurality of second pin holes spaced apart in a circumferential direction, wherein the third journal is engaged with one of the plurality of second pin holes in a clearance fit, and the output shaft disc is fixedly connected to a steering gear of the automobile.

2. The active steering system according to claim 1 , wherein
an eccentricity between the eccentric shaft and the boss is the same as an eccentricity between the first journal and the second journal.

3. The active steering system according to claim 1 , wherein
one end of the eccentric shaft is provided with a first shaft journal; and a plurality of grooves spaced apart are arranged at an end of the first shaft journal away from the eccentric shaft in a circumferential direction.

4. The active steering system according to claim 3 , further comprising:
an electromagnet axially provided with a shear pin, wherein a spring is arranged between the electromagnet and the shear pin;
when the electromagnet is de-energized, the shear pin moves away from the electromagnet by resilience of the spring and engages with one of the plurality of grooves, such that the eccentric shaft is locked; when the electromagnet is energized, the shear pin compresses the spring to move towards the electromagnet and is disengaged from one of the plurality of grooves, such that the eccentric shaft is unlocked.

5. The active steering system according to claim 1 , further comprising:
a first ring groove arranged at an end of the hollow shaft away from the ring gear sleeve and provided with a first circlip for axially fixing the eccentric shaft;
a second ring groove arranged outside the hollow shaft between the first ring groove and the ring gear sleeve and provided with a second circlip for axially fixing the second gear.

6. The active steering system of claim 4 , further comprising:
a first housing;
a second housing detachably connected to the first housing;
an electromagnet box fixedly disposed on the first housing, wherein the electromagnet is fixedly disposed on the electromagnet box;
a hollow connecting shaft protruding from a center of an end of the output shaft disc for fixed connection to the steering gear of the automobile;
wherein two ends of the first input shaft are rotatably supported on the first housing and the second housing, respectively; an end of the second input shaft is rotatably supported on the first housing; one end of the eccentric shaft is rotatably supported on the first housing, and the other end of the eccentric shaft is rotatably supported in the hollow shaft; the hollow shaft is rotatably supported on the second housing; the hollow connecting shaft is rotatably supported on the second housing.

7. The active steering system according to claim 5 , further comprising:
a rotary valve fixedly connected to the hollow connecting shaft;
the steering gear, including a steering pinion and a steering rack, an upper end of the steering pinion being fixedly connected to an output end of the rotary valve;
a steering gear case, wherein the steering rack is arranged in the steering gear case, a lower end of the steering pinion engages with the steering rack, and the steering pinion is axially movable along the steering gear case;
a hydraulic cylinder, wherein an end of the hydraulic cylinder is fixedly connected to an end of the steering gear case;
wherein the hydraulic cylinder is provided with a piston rod; one end of the piston rod is fixedly connected to one end of the steering rack and the other end of the piston rod is connected to a first tie rod; and the other end of the steering rack is connected to a second tie rod;
a first dust cover sleeved on the hydraulic cylinder, wherein one end of the first dust cover is sealingly connected to another end of the hydraulic cylinder, and the other end of the first dust cover is sealingly connected to a diameter-reduced position of an end of the piston rod;
a second dust cover sleeved on the steering gear case, one end of the second dust cover being sealingly connected to another end of the steering gear case, and the other end of the second dust cover being sealingly connected to a diameter-reduced position of an end of the steering rack.

8. The active steering system according to claim 5 , further comprising:
a steering shaft, wherein an end of the steering shaft is fixedly connected to the steering wheel of the automobile;
a steering transmission shaft, wherein one end of the steering transmission shaft is connected to another end of the steering shaft via a first universal joint and the other end of the steering transmission shaft being connected to the first input shaft via a second universal joint.

9. A method for controlling the active steering system of claim 1 , comprising:
S1: acquiring, by the CAN bus, an automobile speed;
S2: acquiring a steering system transmission ratio by reading a relationship data sheet of the steering system transmission ratio and the automobile speed;
S3: collecting, by the active steering system controller, signals of each sensor including a steering wheel angle signal and a steering wheel torque signal;
S4: calculating a steering angle to be output by the coupled motor according to the steering wheel angle signal, the steering wheel torque signal, and the steering system transmission ratio under current operating conditions;
S5: controlling, by the coupled motor controller, the coupled motor to output the steering angle to realize active steering of the automobile.

10. The method according to claim 9 , further comprising:
before S2, determining the working state of the coupled motor; then, if the coupled motor fails, controlling, by the coupled motor controller, the coupled motor to stop working and the electromagnet to de-energize; wherein the shear pin pops out to lock the eccentric shaft.

Assignees

• Univ Jilin

Inventors

• Wang Junnian
• Guo Dedong
• Luo Zheng

Classifications

• B62D5/008 Primary

  Changing the transfer ratio between the steering wheel and the steering gear by variable supply of energy, e.g. by using a superposition gear · CPC title

• B62D6/00

  Arrangements for automatically controlling steering depending on driving conditions sensed and responded to, e.g. control circuits (means for initiating a change in direction B62D1/00; steering valves B62D5/06; combined with means for inclining the vehicle body or wheels on bends B62D9/00) · CPC title

• B62D5/12

  Piston and cylinder · CPC title

• B62D3/14

  hydraulic · CPC title

• B62D6/002

  computing target steering angles for front or rear wheels (B62D7/159 takes precedence) · CPC title