CN111051183A - Steering device - Google Patents
Steering device Download PDFInfo
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- CN111051183A CN111051183A CN201880050831.6A CN201880050831A CN111051183A CN 111051183 A CN111051183 A CN 111051183A CN 201880050831 A CN201880050831 A CN 201880050831A CN 111051183 A CN111051183 A CN 111051183A
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- steering
- motor actuator
- output shaft
- nut
- motor
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- 230000007246 mechanism Effects 0.000 claims abstract description 152
- 230000005540 biological transmission Effects 0.000 claims description 22
- 230000009467 reduction Effects 0.000 claims description 16
- 230000033001 locomotion Effects 0.000 claims description 10
- 230000008878 coupling Effects 0.000 claims description 5
- 238000010168 coupling process Methods 0.000 claims description 5
- 238000005859 coupling reaction Methods 0.000 claims description 5
- 230000004044 response Effects 0.000 abstract description 4
- 238000000034 method Methods 0.000 description 27
- 230000008569 process Effects 0.000 description 26
- 230000005856 abnormality Effects 0.000 description 7
- 230000004043 responsiveness Effects 0.000 description 7
- 230000008859 change Effects 0.000 description 5
- 230000000694 effects Effects 0.000 description 5
- 230000004308 accommodation Effects 0.000 description 4
- 239000002184 metal Substances 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- 230000006872 improvement Effects 0.000 description 3
- 230000002093 peripheral effect Effects 0.000 description 3
- 238000011144 upstream manufacturing Methods 0.000 description 3
- 238000004891 communication Methods 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 230000010354 integration Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 241000755266 Kathetostoma giganteum Species 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 238000012217 deletion Methods 0.000 description 1
- 230000037430 deletion Effects 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 230000035939 shock Effects 0.000 description 1
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
- B62D—MOTOR VEHICLES; TRAILERS
- B62D5/00—Power-assisted or power-driven steering
- B62D5/04—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear
- B62D5/0442—Conversion of rotational into longitudinal movement
- B62D5/0445—Screw drives
- B62D5/0448—Ball nuts
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
- B62D—MOTOR VEHICLES; TRAILERS
- B62D15/00—Steering not otherwise provided for
- B62D15/02—Steering position indicators ; Steering position determination; Steering aids
- B62D15/021—Determination of steering angle
- B62D15/0235—Determination of steering angle by measuring or deriving directly at the electric power steering motor
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
- B62D—MOTOR VEHICLES; TRAILERS
- B62D3/00—Steering gears
- B62D3/02—Steering gears mechanical
- B62D3/04—Steering gears mechanical of worm type
- B62D3/06—Steering gears mechanical of worm type with screw and nut
- B62D3/08—Steering gears mechanical of worm type with screw and nut using intermediate balls or the like
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
- B62D—MOTOR VEHICLES; TRAILERS
- B62D5/00—Power-assisted or power-driven steering
- B62D5/04—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear
- B62D5/0442—Conversion of rotational into longitudinal movement
- B62D5/0454—Worm gears
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
- B62D—MOTOR VEHICLES; TRAILERS
- B62D5/00—Power-assisted or power-driven steering
- B62D5/04—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear
- B62D5/0457—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear characterised by control features of the drive means as such
- B62D5/046—Controlling the motor
- B62D5/0463—Controlling the motor calculating assisting torque from the motor based on driver input
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
- B62D—MOTOR VEHICLES; TRAILERS
- B62D5/00—Power-assisted or power-driven steering
- B62D5/04—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear
- B62D5/0457—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear characterised by control features of the drive means as such
- B62D5/0481—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear characterised by control features of the drive means as such monitoring the steering system, e.g. failures
- B62D5/0484—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear characterised by control features of the drive means as such monitoring the steering system, e.g. failures for reaction to failures, e.g. limp home
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
- B62D—MOTOR VEHICLES; TRAILERS
- B62D5/00—Power-assisted or power-driven steering
- B62D5/06—Power-assisted or power-driven steering fluid, i.e. using a pressurised fluid for most or all the force required for steering a vehicle
- B62D5/065—Power-assisted or power-driven steering fluid, i.e. using a pressurised fluid for most or all the force required for steering a vehicle characterised by specially adapted means for varying pressurised fluid supply based on need, e.g. on-demand, variable assist
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
- B62D—MOTOR VEHICLES; TRAILERS
- B62D6/00—Arrangements for automatically controlling steering depending on driving conditions sensed and responded to, e.g. control circuits
- B62D6/04—Arrangements for automatically controlling steering depending on driving conditions sensed and responded to, e.g. control circuits responsive only to forces disturbing the intended course of the vehicle, e.g. forces acting transversely to the direction of vehicle travel
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H25/00—Gearings comprising primarily only cams, cam-followers and screw-and-nut mechanisms
- F16H25/18—Gearings comprising primarily only cams, cam-followers and screw-and-nut mechanisms for conveying or interconverting oscillating or reciprocating motions
- F16H25/20—Screw mechanisms
- F16H25/22—Screw mechanisms with balls, rollers, or similar members between the co-operating parts; Elements essential to the use of such members
- F16H25/2204—Screw mechanisms with balls, rollers, or similar members between the co-operating parts; Elements essential to the use of such members with balls
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Transportation (AREA)
- General Engineering & Computer Science (AREA)
- Power Steering Mechanism (AREA)
- Steering Control In Accordance With Driving Conditions (AREA)
Abstract
The steering device of the present invention has the following structure: a first motor actuator (20L) is provided in the first electric power steering mechanism (16L), a second motor actuator (20R) is provided in the second electric power steering mechanism (16R), and the first and second motor actuators are controlled by control devices (22L, 22R). By controlling the first electric power steering mechanism (16L) and the second electric power steering mechanism (16R) differently, arbitrary steering controllability can be provided, and steering characteristics can be improved. Further, since the steering assist force is provided by the motor actuators (20L, 20R), the response is high, and the steering controllability can be further improved.
Description
Technical Field
The present invention relates to a steering device for steering a pair of wheels of an automobile, and more particularly to a steering device including steering mechanisms corresponding to the respective wheels.
Background
In an automobile, a power steering apparatus is used to assist a steering force of a steering wheel (hereinafter, referred to as a steering assist force). The power steering apparatus is generally configured as follows: the sector gear is driven by a piston operated by hydraulic pressure, and a link system coupled to the wheels is operated by the sector gear, thereby providing a steering assist force.
In addition, for example, in an automobile such as a truck, a large steering force is required, and therefore, a further assist steering force is required. Therefore, a steering assist force is provided by a steering mechanism that hydraulically drives each of paired wheels of an automobile. For example, japanese patent application laid-open No. 2002-: hydraulically driven pistons are provided in links connected to the respective wheels, and the hydraulic pressure acting on the respective pistons is controlled in accordance with the steering of the steering wheel to enhance the steering assist force. In this case, the hydraulic pressure from the hydraulic pump is controlled by the control valve and acts on each piston via the pipe.
Further, in the above patent document 1, the steering mechanisms corresponding to the respective wheels are provided in order to increase the steering assist force, but the steering mechanisms corresponding to the respective wheels may be provided for other purposes. For example, such a configuration may be adopted in order to improve the steering responsiveness.
Prior art documents
Patent document
Patent document 1: 2002 laid-open patent publication No. 87311
Disclosure of Invention
Problems to be solved by the invention
However, in recent automobiles, there is a demand for improvement in operability of various operating devices for a rider, and there is no exception to the steering performance of a steering wheel for steering the automobile. Therefore, the situation where the steering assist force to be provided to each wheel is rapidly provided is also a development target required for improving the steering performance, and a technique for achieving the development target is strongly required.
The present invention provides a new steering device which can improve the steering performance by rapidly providing steering assist force to each wheel.
Means for solving the problems
The present invention is characterized by comprising a first steering mechanism, a second steering mechanism, and a coupling member, (1) the first steering mechanism comprises a first ball-nut steering unit and a first motor actuator, the first ball-nut steering unit comprises a first output shaft rotatable about a rotation axis of the first output shaft, a first ball screw driving the first nut so that the first nut moves in a direction of the rotation axis of the first output shaft in accordance with the rotation of the first output shaft, a first nut, and a first transmission mechanism steering a first steering wheel in accordance with the movement of the first nut, the first motor actuator is a first electric motor that applies a rotational force to the first output shaft, and the second steering mechanism comprises a second ball-nut steering unit and a second motor actuator, the second ball-nut steering unit includes a second output shaft rotatable about a rotation axis of the second output shaft, a second ball screw driving a second nut so as to move in a direction of the rotation axis of the second output shaft in accordance with the rotation of the second output shaft, a second nut turning a second steering wheel in accordance with the movement of the second nut, and a second transmission mechanism coupling the first transmission mechanism and the second transmission mechanism so that the movement of the first transmission mechanism and the second transmission mechanism can be linked (3) wherein the second motor actuator is a second electric motor applying a rotational force to the second output shaft.
ADVANTAGEOUS EFFECTS OF INVENTION
According to the present invention, by differently controlling the first steering mechanism and the second steering mechanism controlled by the electric actuator, it is possible to provide arbitrary steering controllability and improve steering performance.
Drawings
Fig. 1 is a configuration diagram showing a configuration of a steering system according to an embodiment of the present invention.
Fig. 2 is a sectional view showing the structure of one electric steering mechanism that is not coupled to the steering wheel.
Fig. 3 is a sectional view showing a structure of one electric steering mechanism coupled to a steering wheel.
Fig. 4 is a cross-sectional view showing another structure of one electric steering mechanism coupled to a steering wheel.
Fig. 5 is a control block diagram showing the configuration of the control device shown in fig. 1.
Fig. 6 is a control flow chart illustrating specific control of the control device shown in fig. 1.
Detailed Description
The embodiments of the present invention will be described in detail below with reference to the drawings, but the present invention is not limited to the embodiments below, and various modifications and application examples are included within the scope of the technical concept of the present invention.
Fig. 1 shows a structure of a steering system as a representative embodiment of the present invention. The front wheels on the front side of the automobile are provided as a pair of wheels (hereinafter referred to as steered wheels), and include a first steered wheel 10L and a second steered wheel 10R. The first steered wheel 10L and the second steered wheel 10R are linked by a tie rod 11.
A first link arm 12L and a second link arm 12R are coupled to both ends of the link 11, respectively, and the two link arms 12L and 12R are coupled to the first steering wheel 10L and the second steering wheel 10R, respectively. Thereby, the first steered wheels 10L and the second steered wheels 10R are configured to be steerable in conjunction with each other.
The first steered wheel 10L is coupled to the first electric power steering mechanism 16L via the first steering arm 13L, the first trailing arm 14L, and the first steering arm 15L. Similarly, the second steered wheel 10R is coupled to the second electric power steering mechanism 16R via the second steered arm 13R, the second drag link 14R, and the second steered arm 15R. In the following description, the links and the arms from the first electric power steering mechanism 16L and the second electric power steering mechanism 16R to the first steered wheels 10L and the second steered wheels 10R may be collectively referred to simply as a "link system (coupling member)".
The second electric power steering mechanism 16R is coupled to a steering wheel 18 via a steering shaft 17, and the second electric power steering mechanism 16R drives and steers the steering arm 15R by operating the steering wheel 18. At this time, of course, as will be described later, the steering assist force is provided by the first electric power steering mechanism 16L and the second electric power steering mechanism 16R.
The first electric power steering mechanism 16L is constituted by a first integrated gear box (hereinafter simply referred to as a first gear box) 19L and a first motor actuator 20L that controls a ball nut type steering unit incorporated in the first gear box 19L.
Similarly, the second electric power steering mechanism 16R includes a second integrated gear box (hereinafter, simply referred to as a second gear box) 19R and a second motor actuator 20R that controls a ball-nut type steering unit incorporated in the second gear box 19R. The second electric power steering mechanism 16R is provided with a torque sensor 21 that detects the operation torque of the steering wheel 18.
The first motor actuator 20L of the first electric power steering mechanism 16L is controlled by the first control device 22L, and similarly, the second motor actuator 20R of the second electric power steering mechanism 16R is controlled by the second control device 22R. The first control device 22L and the second control device 22R communicate with each other via the communication line, and exchange control information, failure information, and abnormality information with each other.
In addition, the first control device 22L and the second control device 22R may be configured as the integrated control device 23 so as not to be separated from each other, and in this case, the first electric power steering mechanism 16L and the second electric power steering mechanism 16R may be controlled by the integrated control device 23. The first control device 22L may be of an electromechanical integration type integrally incorporated in the first electric power steering mechanism 16L, and the second control device 22R may be of an electromechanical integration type integrally incorporated in the second electric power steering mechanism 16R.
In this way, the first electric power steering mechanism 16L includes the first motor actuator 20L, and the second electric power steering mechanism 16R includes the second motor actuator 20R, and is configured to be controlled by the respective control devices 22L and 22R.
Therefore, by differently controlling the first electric power steering mechanism 16L and the second electric power steering mechanism 16R, it is possible to provide arbitrary steering controllability and to improve the steering performance. Further, since the steering assist force is provided by the motor actuators 20L and 20R, the steering assist force is large and the response is fast, so that the steering controllability can be further improved.
Next, a specific configuration of the first electric power steering mechanism 16L and the second electric power steering mechanism 16R will be described with reference to fig. 2 and 3, in which fig. 2 shows the first electric power steering mechanism 16L and fig. 3 shows the second electric power steering mechanism 16R.
In fig. 2 showing the first electric power steering mechanism 16L, a first nut 27L that slides in the axial direction of the first housing 25L is housed in a first internal housing space 26L of a bottomed, elongated, hollow cylindrical first housing 25L having one open end, and a first rack portion (first transmission mechanism) 28L is formed in a part of the first nut 27L, here, a side periphery of the first nut 27L.
The first housing 25L is made of metal, and the first nut 27L accommodated in the first internal accommodation space 26L is configured such that first large diameter portions 29L are formed at both ends, and the first large diameter portions 29L slide on the inner peripheral surface of the first internal accommodation space 26L. The first rack portion 28L is formed in the small diameter portion 30L between the two first large diameter portions 29L.
A first sector gear housing portion 31L is integrally formed on a side surface of the first housing 25L, and a first sector gear 32L is housed and disposed in the first sector gear housing portion 31L. The first sector gear 32L meshes with the first rack portion 28L formed in the first nut 27L, and in the state shown in fig. 2, the first sector gear 32L rotates in the clockwise direction (positive direction) and the counterclockwise direction (negative direction) by the sliding movement of the first nut 27L in the left-right direction.
The first sector gear 32L is coupled to the first steering arm 15L shown in fig. 1, and the rotation operation of the first sector gear 32L is transmitted to the first steering arm 15L, whereby the first steered wheel 10L is steered.
A spiral "thread groove" is cut in the axial direction (sliding direction) of the first nut 27L, and a first output shaft 34L including a first ball screw shaft 33L is screwed into the thread groove. The rotation axis Cr1 of the first output shaft 34L coincides with the axial center of the first nut 27L in the sliding direction, and when the first output shaft 34L rotates around the rotation axis Cr1, the first nut 27L slides left and right in the drawing. Here, the first output shaft 34L, the first ball screw 33L, the first nut 27L, and the first rack portion 28L constitute a first ball-nut steering unit.
A first bearing member 35L made of metal is liquid-tightly attached to the open end of the first housing 25L, and a first ball bearing (a)36L is provided at the center of the first bearing member 35L. The first output shaft 34L is inserted through the first ball bearing (a)36L so as to be capable of supporting the shaft, and the end of the inserted first output shaft 34L is supported by the first ball bearing (B) 37L. The first ball bearing (B)37L is fixed to the first cover 38L, and the first cover 38L is liquid-tightly sealed around a speed reduction mechanism described later.
A first worm wheel 39L is fixed to an end portion of the first output shaft 34L located between the first bearing member 35L and the first cover 38L, and the first worm wheel 39L meshes with the first worm 40L, thereby forming a speed reduction mechanism. The first worm 40L is fixed to a rotation shaft of the first electric motor 41L so as to be driven by the first electric motor 41L.
The first electric motor 41L is fixed to the outer surface of the first housing 25L such that the rotation axis of the rotation shaft of the first electric motor 41L is positioned in the direction orthogonal to the rotation axis Cr1 of the first output shaft 34L. This makes it possible to reduce the volume of the first electric power steering mechanism 16L in the longitudinal direction (the direction of the rotation axis Cr1 of the first output shaft 34L), and to improve the flexibility (layout) when the electric power steering mechanism is mounted in an automobile.
Further, since the speed reduction mechanism is constituted by the first worm wheel 39L and the first worm 40L, the size can be reduced, and the size and weight increase of the steering apparatus can be suppressed. Further, since the rotational force of the first electric motor 41L is decelerated and amplified, the following operation and effect can be obtained: a small electric motor can be used, or the steering assist force can be increased without downsizing.
Further, since a hydraulic system is not used, a hydraulic pump, a hydraulic pipe, and the like are not required, and the system can be simplified, and in addition, since an electric control signal is transmitted to the first electric motor 41L to supply the steering assist force, an operation and an effect with high responsiveness can be obtained. This high responsiveness is associated with further improvement of the steering control characteristics obtained in the control flow described later.
In the first electric power steering mechanism 16L having the above-described configuration, when a drive control signal (corresponding to the steering assist force) is supplied from the first control device 22L to the first electric motor 41L, the first electric motor 41L rotationally drives the first output shaft 34L via the first worm 40L and the first worm wheel 39L. When the first output shaft 34L rotates, the first nut 27L is slidingly moved by the first ball screw 33L, so that the first rack portion 28L can rotate the first sector gear 32L and apply a steering assist force to the first steered wheel 10L via the link system.
Next, a specific configuration of the second electric power steering mechanism 16R will be described. In fig. 3 showing the second electric power steering mechanism 16R, a second nut 27R that slides in the axial direction of the second case 25R is housed in a second internal housing space 26R of a bottomed, elongated, hollow cylindrical second case 25R having one open end, and a second rack portion (second transmission mechanism) 28R is formed in a part of the second nut 27R, here, a side peripheral portion of the second nut 27R.
The second case 25R is made of metal, and the second nut 27R accommodated in the second internal accommodation space 26R is configured such that second large-diameter portions 29R are formed at both ends, and the second large-diameter portions 29R slide on the inner peripheral surface of the internal accommodation space 26R. The second rack portion 28R is formed on the second small diameter portion 30R between the two second large diameter portions 29R.
A second sector gear housing portion 31R is integrally formed on a side surface of the second housing 25R, and a second sector gear 32R is housed and disposed in the second sector gear housing portion 31R. The second sector gear 32R meshes with the second rack portion 28R formed on the second nut 27R, and in the state shown in fig. 3, the second sector gear 32R rotates in the clockwise direction (positive direction) and the counterclockwise direction (negative direction) by the sliding movement of the second nut 27R in the right and left directions.
The second sector gear 32R is coupled to the second steering arm 15R shown in fig. 1, and the rotational operation of the second sector gear 32R is transmitted to the second steering arm 15R, whereby the second steered wheel 10R is steered.
A spiral "thread groove" is cut in the axial direction (sliding direction) of the second nut 27R, and a second output shaft 34R including a second ball screw 33R is screwed into the thread groove. The rotation axis Cr2 of the second output shaft 34R coincides with the axial center of the second nut 27R in the sliding direction, and when the second output shaft 34R rotates around the rotation axis Cr2, the second nut 27R slides left and right in the drawing. Here, the second output shaft 34R, the second ball screw shaft 33R, the second nut 27R, and the second rack portion 28R constitute a second ball-nut type steering unit.
A second bearing member 35R made of metal is liquid-tightly attached to the open end of the second housing 25R, and a second ball bearing (a)36R is provided at the center of the second bearing member 35R. The second output shaft 34R is inserted through the second ball bearing (a)36R so as to be capable of supporting a shaft. One end of a torsion bar 43, which will be described later, is fixed to an internal space in the vicinity of the end portion of the second output shaft 34R.
A second worm wheel 39R is fixed to the outer periphery of the end portion of the second output shaft 34R that penetrates through the second bearing member 35R, and the second worm wheel 39R meshes with the second worm 40R, thereby forming a speed reduction mechanism. The second worm wheel 39R is fixed to a rotation shaft of the second electric motor 41R so as to be driven by the second electric motor 41R.
The second electric motor 41R is also fixed to the outer surface of the second housing 25R such that the rotation axis of the rotation shaft of the second electric motor 41L is positioned in the direction orthogonal to the rotation axis Cr2 of the second output shaft 34R. This makes it possible to reduce the volume of the second electric power steering mechanism 16R in the longitudinal direction (the direction of the rotation axis Cr2 of the second output shaft 34R), and to improve the flexibility (layout) when the electric power steering mechanism is mounted in the vehicle.
Since the speed reduction mechanism is constituted by the second worm wheel 39R and the second worm 40R, as in the first electric power steering mechanism 16L, the size can be reduced, and the size and weight increase of the steering apparatus can be suppressed. Further, since the rotational force of the second electric motor 41R is decelerated and amplified, the following operation and effect can be obtained: a small electric motor can be used, or the steering assist force can be increased without downsizing.
Further, as in the case of the first electric power steering mechanism 16L, since a hydraulic system is not used, a hydraulic pump, a hydraulic pipe, and the like are not required, and the system can be simplified, and in addition, since an electric control signal is transmitted to the second electric motor 41R to supply the steering assist force, an operation and an effect with high responsiveness can be obtained. This high responsiveness is associated with further improvement of the steering control characteristics obtained in the control flow described later.
Here, the second electric power steering mechanism 16R is provided with an input shaft 42 coupled to the steering shaft 17 fixed to the steering wheel 18, and the other end of the torsion bar 43 is fixed to the input shaft 42 and coupled to the second output shaft 34R. Therefore, the torsion bar 43 twists between the second output shaft 34R and the input shaft 42, and the amount of the torsion can be measured to detect the torque.
Thus, the second output shaft 34R is connected to the steering wheel 18 via the input shaft 42. Thus, the steering wheel 18 is connected to the side of the second electric motor 41R that outputs a large torque in the same direction as the steering direction, so that the driver can easily feel the responsiveness of the steering assist, and the steering feel can be improved.
In order to detect torsion of the torsion bar 43, a first angle sensor 44 is attached to the input shaft 42, and a second angle sensor 45 is attached to the second output shaft 34R. Also, the steering torque is detected based on the relative rotation angles detected by the first angle sensor 44 of the input shaft 42 and the second angle sensor 45 of the second output shaft. The first angle sensor 44 and the second angle sensor 45 may detect an input from the input shaft 42 and an inverse input from the second output shaft 34R. This will be described based on a control flowchart to be described later.
The input shaft 42 is supported by the second ball bearing (B)37R, and the second ball bearing (B)37R is fixed to the second cover 38R. The second cover 38R encloses the speed reduction mechanism including the worm wheel 39R and the worm 40R, the first angle sensor 44 and the second angle sensor 45 constituting the torque sensor in a liquid-tight manner.
Here, by detecting the traveling direction of the mutual phase of the first angle sensor 44 and the second angle sensor 45, it is possible to detect with high accuracy whether the input is from the steering wheel or the reverse input from the road surface.
As is apparent from fig. 2 and 3, the first electric power steering mechanism 16L and the second electric power steering mechanism 16R have substantially the same shape, and in particular, the housings 25L and 25R, the nuts 27L and 27R, and the sector gears 32L and 32R have the same shape. Therefore, the parts can be shared, and the manufacturing cost can be reduced.
The first and second nuts 27L and 27R and the first and second sector gears 32L and 32R may have the same tooth size, and the other portions may be slightly different. Further, although the casings 25L and 25R may have different shapes depending on the case, at least the nuts 27L and 27R and the sector gears 32L and 32R may be shared.
In the second electric power steering mechanism 16R having the above configuration, when the drive control signal (corresponding to the steering assist force) is supplied from the second control device 22R to the second electric motor 41R, the second electric motor 41R rotationally drives the second output shaft 34R via the second worm 40R and the second worm wheel 39R. When the second output shaft 34R rotates, the second nut 27R is slidingly moved by the second ball screw 33R, so that the second rack portion 28R can rotate the second sector gear 30 and apply a steering assist force to the second steered wheel 10R via the link system.
In the second electric power steering mechanism 16R shown in fig. 3, the steering torque is detected by the first angle sensor 44 and the second angle sensor 45, but the steering torque can be detected even if hall elements are used. Fig. 4 is a diagram for detecting steering torque using a hall element, and is basically the same as the configuration of fig. 3, and therefore, the same reference numerals are omitted from description.
In fig. 4, a magnetic torque sensor 46 using a permanent magnet or a hall element is provided between the second output shaft 34R and the input shaft 42, whereby the steering torque can be detected. Of course, if two magnetic torque sensors are used, the input from the input shaft 42 or the reverse input from the second output shaft 34R can be detected, as in the second electric power steering mechanism 16R shown in fig. 3.
The second electric power steering mechanism 16R may be applied to a steering column assist type steering device. That is, the second output shaft 34R of the second electric power steering mechanism 16R is interlocked to assist the steering column, whereby the steering force can be applied to the steering column as in the embodiment. With such a configuration, the present invention can be applied to an automobile such as a flat-head truck having a small space under the driver's feet, and the layout can be improved.
Next, control of the first electric motor 41L of the first electric power steering mechanism 16L and the second electric motor 41R of the second electric power steering mechanism 16R will be described. Basically, the first electric motor 41L is controlled by the first control device 22L, and the second electric motor 41R is controlled by the second control device 22R.
In fig. 5, the first control device 22L is configured by a vehicle speed determination unit 50 to which vehicle speed information for determining the vehicle speed of the automobile is input, a first motor failure determination unit 51L to which a motor state signal of the first electric motor 41L is input and which determines a failure or abnormality of the first electric motor 41L, a first electric motor assist operation unit 52L to which vehicle speed information from the vehicle speed determination unit 50, second electric motor failure information from a second motor failure determination unit 51R of the second control device 22R described later, and torque information from a torque determination unit 55 of the second control device 22R described later are input and which determines a drive control amount of the first electric motor 41L, the first electric motor driving section 53L sets a drive control amount of the first electric motor 41L and generates a drive control signal of the first electric motor 41L.
Here, the vehicle speed determination unit 50, the first motor failure determination unit 51L, and the first electric motor auxiliary operation unit 52L are functional blocks executed by a program of the first microcomputer 24L, and the first electric motor drive unit 53L is an output circuit thereof. Details of these functional blocks are explained in the control flowchart shown in fig. 6.
The second control device 22R includes a second motor failure determination unit 51R, a disturbance determination unit 54, a torque determination unit 55, a second electric motor assist operation unit 52R, and a second electric motor drive unit 53R, the second motor failure determination unit 51R receives a motor information signal of the second electric motor 41R and determines a failure or abnormality of the second electric motor 41R, the disturbance determination unit 54 receives sensor information of the first angle sensor 44 and the second angle sensor 45 and determines disturbance from the steering wheels 10L and 10R, the torque determination unit 55 determines a torque based on disturbance information from the disturbance determination unit 54 or sensor information of the first angle sensor 44 and the second angle sensor 45, and the second electric motor assist operation unit 52R receives first electric motor failure information from the first motor failure determination unit 51L of the first control device 22L, And torque information from the torque determination unit 55, and obtains a drive control amount of the second electric motor 41R, and the second electric motor drive unit 53R sets the drive control amount of the second electric motor 41R and generates a drive control signal of the second electric motor 41R.
Similarly to the first control device 22L, the second motor failure determination unit 51R, the disturbance determination unit 54, the torque determination unit 55, and the second electric motor assist operation unit 52R are functional blocks executed by a program of the second microcomputer 24R, and the second electric motor drive unit 53R is an output circuit thereof. Details of these functional blocks are also explained in the control flowchart shown in fig. 6.
The first control device 22L and the second control device 22R are connected by a communication line, and when an abnormality or failure occurs in the microcomputer 24L of the first control device 22L or the microcomputer 24R of the second control device 22R, the steering control is executed by the microcomputer on the other hand.
Thus, the first microcomputer 24L and the second microcomputer 24R can constitute a redundant steering system, and even when one of the microcomputers fails in function, the other microcomputer can continue to execute the steering control. Further, as indicated by a broken line arrow, the drive control amount calculated by the normal microcomputer may be transmitted to the electric motor driving unit in which the failure occurs, thereby operating both the electric steering mechanisms.
Even if a failure such as an abnormality or a failure occurs in the first electric motor 41L or the second electric motor 41R, the steering function can be maintained on the normal electric motor side. Thus, a redundant steering system can be configured by the first electric motor 41L and the second electric motor 41R, and even when one electric motor fails, the steering control can be continued in the other electric motor. In this case, when the speed reduction mechanism that has failed has the function of the reverse efficiency, a mechanism for canceling the function of the reverse efficiency may be provided between the speed reduction mechanism and the rack portion.
Next, control of the first control device 22L and the second control device 22R will be described based on a control flowchart shown in fig. 6. The control flow is started at predetermined time intervals, and may be executed by a comparison matching interrupt of a timer built in the microcomputer, for example.
< step S10> in step S10, it is determined based on the torque sensor whether there is a change in steering torque by the rotating operation of the steering wheel 18. This can be determined by detecting the torsion of the torsion bar 41 by the first angle sensor 44 and the second angle sensor 45 provided in the second electric power steering mechanism 16R.
When no torque change is detected without a rotating operation of the steering wheel 18, a return is made to wait for the next start timing. On the other hand, when the steering wheel 18 is turned and a change in the steering torque is detected, the process proceeds to step S11.
< step S11> in step S11, it is determined whether or not interference is detected based on information from the first angle sensor 44 and the second angle sensor 45. Here, the disturbance indicates the reverse input from the steered wheels 10L and 10R, and thus the steering performance is highly likely to be adversely affected. For example, if there is a reverse input due to a change in the shape of a road surface such as a rut, a problem may occur in which the steering stability of the steering wheel 18 is impaired. This may cause the steering positions (i.e., steering angles) of the steered wheels 10L and 10R to vary, making it difficult to ensure stable steering positions.
Since the disturbance is an inverse input, it can be determined by detecting that the phase signal of the second angle sensor 45 provided on the second output shaft 34R precedes the phase signal of the first angle sensor 44 provided on the input shaft 42. On the other hand, if the phase signal of the first angle sensor 44 provided on the input shaft 42 is detected prior to the phase signal of the second angle sensor 45 provided on the second output shaft 34R, it can be determined that the steering wheel 18 is normally operated.
When it is determined that interference is detected, the process proceeds to step S12, and when it is determined that interference is not detected, the process proceeds to step S13.
In step S12, < < step S12> > a motor torque command value that is a drive control amount for holding the current steering position of the first electric motor 41L of the first electric power steering mechanism 16L is calculated so that the steering position does not change even if mechanical shock or the like due to disturbance acts on the steered wheels 10L, 10R. That is, even if an impact is applied to the steered wheels 10L, 10R from ruts, gravel, or the like on the road surface, the current steering position is maintained by the first electric power steering mechanism 16L so that the steering positions of the steered wheels 10L, 10R do not fluctuate. When the motor torque command value is obtained, the process proceeds to step S14.
In step S13, < < step S13> > the motor torque command value calculated in step S12 is set to the first electric motor driving unit 53L, and then a driving current is supplied to the first electric motor 41L to generate a predetermined torque.
In this way, by executing the control steps of each of steps S11, S12, and S13, the steering position of the steered wheels 10L and 10R can be maintained against disturbance from the road surface, and therefore, stable steering control can be performed.
Further, by comparing the progress of the phase of the angle between the upstream side (steering wheel side) and the downstream side (steering wheel side) of the torsion bar 43, it is possible to determine with high accuracy whether the input from the steering wheel is the reverse input (disturbance) from the road surface.
When the drive control of the first electric motor 41L in step S13 is executed, the process returns to the next start timing.
< step S14> return to step S11, and when no disturbance is detected in step S11, it is determined that the steering wheel 18 is normally rotated, and in step S14, it is determined whether or not the state signals of the first electric power steering mechanism 16L and the second electric power steering mechanism 16R are detected. For example, the operation signals of the first electric motor 41L and the second electric motor 41R may be monitored, and the absence of the operation signals or the presence of an abnormality signal may be used to determine an abnormality or a failure state of a failure in the first electric power steering mechanism 16L and the second electric power steering mechanism 16R.
Further, since the first microcomputers 24L and 24R may monitor each other to determine the normality thereof or may determine the normality by another monitoring computer, the determination may be regarded as the failure determination in step S14.
If it is determined that a failure has occurred in the second electric power steering mechanism 16R, the process proceeds to step S15, and if it is determined that a failure has occurred in the first electric power steering mechanism 16L, the process proceeds to step S17. On the other hand, if it is determined that both the first electric power steering mechanism 16L and the second electric power steering mechanism 16R have not failed, that is, if it is determined that they are normal, the routine proceeds to step S19.
In step S15, < < step S15> because it is determined that a failure has occurred in the second electric power steering mechanism 16R, a motor torque command value, which is a drive control amount of the first electric motor 41L of the first electric power steering mechanism 16L, is calculated based on the detected torque corresponding to the operation amount of the steering wheel 18. That is, the steering assist force corresponding to the operation amount of the steering wheel 18 is obtained, and the steering assist by the first electric motor 41L is executed.
In this case, since the second electric motor 41R fails, the steering assist force is weakened accordingly, and therefore, the motor torque value of the first electric motor 41L may be set large. At this time, the operation of the second electric motor driving unit 53R may be prohibited so that the drive control signal is not supplied to the second electric motor 41R. When the motor torque command value based on the detected torque is obtained, the process proceeds to step S16.
In step S16, < < step S16> > the motor torque command value calculated in step S15 is set to the first electric motor driving unit 53L, and then a driving current is supplied to the first electric motor 41L to generate a predetermined torque.
In this way, in steps S14, S15, and S16, a redundant system is formed by the first electric motor 41L and the second electric motor 41R, and when the second electric motor 41R fails, the application of the steering assist force can be continued by the first electric motor 41L. Further, the first microcomputer 24L and the second microcomputer 24R also form a redundant system, so that even when the second microcomputer fails, the application of the steering assist force can be continued by the first microcomputer 24L.
When the drive control of the first electric motor 41L in step S16 is executed, the process returns to the next start timing.
< step S17> returns to step S14, and when it is determined that a failure has occurred in the first electric power steering mechanism 16L, the routine proceeds to step S17. In step S17, since it is determined that a failure has occurred in the first electric power steering mechanism 16L, a motor torque command value, which is a drive control amount of the second electric motor 41R of the second electric power steering mechanism 16R, is calculated based on the detected torque corresponding to the operation amount of the steering wheel 18. That is, the steering assist force corresponding to the operation amount of the steering wheel 18 is obtained, and the steering assist by the second electric motor 41R is executed.
In this case, since the first electric motor 41L fails, the steering assist force is also weakened in accordance with the failure, and therefore, the motor torque value of the second electric motor 41R may be set to be large. At this time, the operation of the first electric motor driving unit 53L may be prohibited so that the drive control signal is not supplied to the first electric motor 41L. When the motor torque command value based on the detected torque is obtained, the process proceeds to step S18.
In step S18, < < step S18> > the motor torque command value calculated in step S17 is set to the second electric motor driving unit 53R, and then a driving current is supplied to the second electric motor 41R to generate a predetermined torque.
In this way, in steps S14, S17, and S18, a redundant system is also formed by the first electric motor 41L and the second electric motor 41R, and when the first electric motor 41L fails, the application of the steering assist force can be continued by the second electric motor 41R. Further, the first microcomputer 24R and the second microcomputer 24R also form a redundant system, so that even when the first microcomputer 24L fails, the application of the steering assist force can be continued by the second microcomputer 24R.
When the drive control of the second electric motor 41R in step S18 is executed, the process returns to the next start timing.
If it is determined in step S19> that the process returns to step S14 and a failure has not occurred in both the first electric power steering mechanism 16L and the second electric power steering mechanism 16R (normal), the process proceeds to step S19. In step S19, it is determined whether or not the detected steering torque is greater than the predetermined steering torque T1. This determination is made with respect to the case where the steering wheel 18 is largely rotated and the vehicle is turned. In this step S19, if a decision is made that the detected steering torque is greater than the predetermined steering torque T1, the process proceeds to step S20, and if a decision is made that the detected steering torque is smaller than the predetermined steering torque T1, the process proceeds to step S23.
In step S20, < < step S20> > the motor torque command values, which are the drive control amounts of the first electric motor 41L and the second electric motor 41R corresponding to the detected steering torque, are calculated in the same direction as the steering direction, which is the rotation direction of the steering wheel 18. That is, the steering assist force corresponding to the operation amount of the steering wheel 18 is obtained, and the steering assist by the first electric motor 41L and the second electric motor 41R is executed. In this case, the motor torque values of the first electric motor 41L and the second electric motor 41R are the same value. When the motor torque command values of the electric motors 41L and 41R are calculated, the process proceeds to step S21.
In step S21, < < step S21> > the motor torque command value calculated in step S20 is set to the second electric motor driving unit 53R, and then a driving current is supplied to the second electric motor 41R to generate a predetermined torque. Here, in the present embodiment, the second electric power steering mechanism 16R is controlled to provide the steering assist force earlier than the first electric power steering mechanism 16L. When the second electric power steering mechanism 16R is driven and controlled in step S21, the process proceeds to step S22.
In step S22, < < step S22> > the motor torque command value calculated in step S20 is set to the first electric motor driving unit 53L, and then a driving current is supplied to the first electric motor 41L to generate a predetermined torque. As described above, in the present embodiment, the first electric power steering mechanism 16L is controlled to provide the steering assist force after the second electric power steering mechanism 16R.
By executing the control steps of steps S21 and S22, it is possible to perform steering assist of the steered wheels 10L and 10R so as to suppress disturbance from the road surface while maintaining the steered positions of the steered wheels 10L and 10R, and to perform stable steering control in which the steered wheels 10L and 10R are less likely to be affected by intrusion of disturbance from the road surface. Here, the time interval between the addition of the steering assist forces of the first electric power steering mechanism 16L and the second electric power steering mechanism 16R is preferably set to a time interval at which the driver does not feel discomfort by adding the steering assist forces to the respective steering assist forces.
Further, the disturbance is high-frequency vibration input from a road surface to a steering wheel when an automobile travels on a rough road surface such as a rut or a gravel road. Therefore, when a signal of a specific frequency (a signal of a predetermined frequency or higher) is detected from the output signal of the torque sensor, for example, the occurrence of interference can be determined.
Alternatively, the determination may be made based on the output signal of the yaw rate sensor. Further, the determination may be made based on vibration of an image of the road surface captured by the camera. Further, it can be determined that a disturbance has occurred when the angle signal on the downstream side precedes the angle signal on the upstream side, based on the phases of the vibrations of the angle signal on the upstream side (steering wheel side) and the angle signal on the downstream side (steering wheel side) of the torsion bar of the torque sensor.
By the execution of the control steps of such steps S20, S21, S22, the second electric power steering mechanism 16R linked to the steering wheel 18 is drive-controlled in advance, so that the driver can easily feel that the steering apparatus is reacting to the steering operation. In addition, by delaying the drive control in response to the second electric motor 41R of the first electric motor 41L, the stability of the steering apparatus can be improved.
In addition, since a large steering assist force is required when the vehicle is turned significantly, the drive control of both the first electric motor 41L and the second electric motor 41R can improve the steering responsiveness and suppress the steering force shortage.
When the drive control of the first electric motor 41L in step S22 is executed, the process returns to the next start timing.
If it is determined in step S19 that the operation amount of the steering wheel 18 is small and the detected steering torque is smaller than the predetermined steering torque T1, < < step S23> then the process proceeds to step S23. The step S23 determines the vehicle speed, and the process proceeds to step S24 when the vehicle speed is slower than the predetermined vehicle speed V1 (low speed running), and proceeds to step S26 when the vehicle speed is faster than the predetermined vehicle speed V1 (high speed running).
In step S24, < < step S24> since the speed of the vehicle is low, obstacles that occur when the speed of the vehicle described later is high are not considered, and the necessity of increasing the steering assist force by that much from step S19 is small, the steering assist force is added only by the second electric power steering mechanism 16R that is interlocked with the steering wheel 18 side. Therefore, in step S24, a motor torque command value, which is a drive control amount of the second electric motor 41R of the second electric power steering mechanism 16R, is calculated based on the detected torque corresponding to the operation amount of the steering wheel 18. When the motor torque command value for the second electric motor 41R is calculated, the process proceeds to step S25.
In step S25, < < step S25> > the motor torque command value calculated in step S24 is set to the second electric motor driving unit 53R, and then a driving current is supplied to the second electric motor 41R to generate a predetermined torque.
In this way, when the amount of operation of the steering wheel 18 is small and the speed of the vehicle is low, the steering assist force is applied only by the second electric power steering mechanism 16R. This can reduce the amount of electric power consumed, and as a result, can reduce the amount of fuel consumed.
When the drive control of the second electric motor 41R in step S25 is executed, the process returns to the next start timing.
< step S26> return to step S23, and since it is determined that the vehicle speed of the vehicle is faster than the predetermined vehicle speed V1, the motor torque command value of the second electric motor 41R is calculated in step S26. Since the motor torque command value is a value for driving the automobile at a high speed, the steering assist force needs to be a value capable of maintaining the steering position at a high level. This is because the vehicle speed is high, and therefore, if the steering position varies, there is a possibility that the vehicle will run in a meandering manner. Therefore, first, in step S26, the steering assist force of the second electric motor 41R required for the steering assist is obtained. When the motor torque command value for the second electric motor 41R is calculated, the process proceeds to step S27.
< step S27> in step S27, a motor torque command value with which steering assist force can be obtained is calculated for the first electric motor 41L, so that the steering position of the steered wheels 10L, 10R is maintained without causing hunting. Here, the motor torque command value of the first electric motor 41L is set smaller than the motor torque command value of the second electric motor 41R. When the motor torque command value for the first electric motor 41L is calculated, the process proceeds to step S28.
In step S28, < < step S28> > the motor torque command value calculated in step S26 is set to the second electric motor driving unit 53R, and then a driving current is supplied to the second electric motor 41R to generate a predetermined torque. When the motor torque command value for the second electric motor 41R is set in the second electric motor driving unit 53R, the process proceeds to step S29.
In step S29, < < step S29> > the motor torque command value calculated in step S27 is set to the first electric motor driving unit 53L, and then a driving current is supplied to the first electric motor 41L to generate a predetermined torque. In this case, as described above, the motor torque of the first electric motor 41L is smaller than the motor torque of the second electric motor 41R. When the drive control of the first electric motor 41L in step S29 is executed, the process returns to the next start timing.
According to steps S26, S27, S28, and S29, the stability of steering during high-speed traveling can be improved, and since the steering assist forces of the first electric motor 41L and the second electric motor 41R are different, the divergence of the motions of both is suppressed, and a stable feeling of steering operation can be obtained.
As described above, according to the present invention, the following structure is adopted: the first electric power steering mechanism is provided with a first motor actuator, the second electric power steering mechanism is provided with a second motor actuator, and the first motor actuator and the second motor actuator are controlled by a control device. In this way, by performing different controls on the first electric power steering mechanism and the second electric power steering mechanism, it is possible to provide arbitrary steering controllability and improve steering performance. Further, since the steering assist force is provided by the motor actuator, the response is fast, and the steering controllability can be further improved.
The present invention is not limited to the above embodiment, and may include various modifications. For example, the above embodiments have been described in detail to explain the present invention in an easily understandable manner, but the present invention is not limited to having all the configurations described above. Note that a part of the structure of one embodiment may be replaced with the structure of another embodiment, or the structure of one embodiment may be added to the structure of another embodiment. In addition, as for a part of the configuration of each embodiment, addition, deletion, and replacement of other configurations may be performed.
As the steering device according to the above-described embodiment, for example, the following can be considered.
That is, as one aspect of the present invention, a steering apparatus includes a first steering mechanism including a first ball-nut steering unit including a first output shaft rotatable about a rotation axis of the first output shaft, a first ball screw driving a first nut so that the first nut moves in a direction of the rotation axis of the first output shaft in accordance with rotation of the first output shaft, a second steering mechanism including a first electric motor that applies a rotational force to the first output shaft, a first nut that drives the first nut in accordance with the movement of the first nut, and a first motor actuator that is a first electric motor that applies a rotational force to the first output shaft, the second steering mechanism includes a second ball nut type steering unit including a second output shaft, a second ball screw, a second nut, and a second transmission mechanism, and a second motor actuator, the second output shaft is rotatable about a rotation axis of the second output shaft, the second ball screw drives the second nut so that the second nut moves in a direction of the rotation axis of the second output shaft in accordance with rotation of the second output shaft, the second transmission mechanism steers a second steerable wheel in accordance with movement of the second nut, the second motor actuator is a second electric motor that applies a rotational force to the second output shaft, the coupling member couples the first transmission mechanism and the second transmission mechanism so that the first transmission mechanism and the second transmission mechanism can be interlocked with each other.
In a preferred aspect of the steering device described above, the steering device includes a control device that drives and controls the first motor actuator and the second motor actuator, and the control device drives and controls the first motor actuator and the second motor actuator so that a torque of the second motor actuator is larger than a torque of the first motor actuator when the second motor actuator is rotated in the same direction as a steering direction of the first steerable wheels and the second steerable wheels.
In another preferred aspect of any of the steering apparatuses described above, the control device controls the driving of the first motor actuator such that the first steerable wheels maintain a steering angle when the second motor actuator is rotated in the same direction as the steering direction of the first steerable wheels and the second steerable wheels.
In still another preferred aspect of any of the steering apparatuses described above, the control device controls the driving of the first motor actuator such that the first steerable wheels maintain a steering angle when the second motor actuator is rotated in the same direction as the steering direction of the second steerable wheels at or above a predetermined vehicle speed.
In still another preferred aspect, in any one of the steering devices described above, the control device controls the driving of the first motor actuator so as to suppress disturbance from a road surface when rotating the second motor actuator in the same direction as the steering direction of the second steered wheels.
In still another preferred aspect, in any one of the above-described steering devices, the second output shaft is connected to a steering wheel.
In still another preferred aspect of any of the steering apparatus described above, the second steering mechanism includes an input shaft, a torsion bar, a first angle sensor, and a second angle sensor, the input shaft is connected with the steering wheel, the torsion bar is arranged between the input shaft and the second output shaft, the first angle sensor detects an angle of the input shaft, the second angle sensor detects an angle of the second output shaft, the control device determines that there is a disturbance from the road surface when the phase of the output signal of the second angle sensor is advanced with respect to the phase of the output signal of the first angle sensor, when the second motor actuator is rotated in the same direction as the steering direction of the second steered wheel, the first motor actuator is drive-controlled so as to suppress disturbance from a road surface.
In still another preferred aspect, in any one of the steering devices described above, the steering device includes a control device that drives and controls the first motor actuator and the second motor actuator, the second output shaft is connected to a steering wheel, and the control device drives and controls the second motor actuator prior to the first motor actuator.
In still another preferred aspect, in any one of the steering apparatuses described above, the first ball nut type steering unit and the second ball nut type steering unit do not have a hydraulic circuit.
In still another preferred aspect, in any one of the steering devices described above, the first steering mechanism has a first speed reduction mechanism provided between the first output shaft and the first motor actuator, and the second steering mechanism has a second speed reduction mechanism provided between the second output shaft and the second motor actuator.
In still another preferred aspect, in any one of the steering devices described above, the first reduction mechanism and the second reduction mechanism are each a combination of a worm and a worm wheel.
In still another preferred embodiment, in any one of the steering apparatuses described above, the first ball nut type steering unit includes a first sector gear that meshes with a first rack formed on the first nut, the second ball nut type steering unit includes a second sector gear that meshes with a second rack formed on the second nut, the first nut and the second nut have the same shape, and the first sector gear and the second sector gear have the same shape.
In still another preferred aspect, in any one of the steering apparatuses described above, the steering apparatus includes a control device that drive-controls the first motor actuator and the second motor actuator, and an input shaft provided in the second steering mechanism, the input shaft being connected to a steering wheel, a torsion bar provided between the input shaft and the second output shaft, and a torque sensor that detects a steering torque of the second steering mechanism based on a relative rotation angle between the input shaft and the second output shaft, and the control device drive-controls the first motor actuator and the second motor actuator based on the steering torque.
In still another preferred embodiment, in any one of the steering devices described above, the control device controls driving of both the first motor actuator and the second motor actuator in the same direction as the rotation direction of the steering wheel when the steering torque is equal to or greater than a predetermined value.
In still another preferred embodiment, in any one of the steering devices described above, the second output shaft is connected to a steering column, and the second motor actuator is provided in the steering column and applies a steering force to the steering column.
In still another preferred aspect, in any one of the steering devices described above, the steering device includes a first control device that drives and controls the first motor actuator and a second control device that drives and controls the second motor actuator, the first control device includes a first microcomputer that calculates a command signal to be output to the first motor actuator, and the second control device includes a second microcomputer that calculates a command signal to be output to the second motor actuator.
In still another preferred aspect of the steering device according to any one of the above aspects, when one of the first motor actuator and the second motor actuator fails, the other motor actuator continues to be drive-controlled.
In still another preferred aspect of the steering device according to any one of the first and second microcomputers, when one of the first and second microcomputers fails, the other microcomputer continues to be drive-controlled.
Claims (18)
1. A steering device is characterized by comprising a first steering mechanism, a second steering mechanism and a connecting member,
the first steering mechanism includes a first ball nut type steering unit and a first motor actuator,
the first ball nut type steering unit includes a first output shaft, a first ball screw, a first nut, and a first transmission mechanism,
the first output shaft is rotatable about a rotational axis of the first output shaft,
the first ball screw drives the first nut so that the first nut moves in the direction of the rotation axis of the first output shaft in accordance with the rotation of the first output shaft,
the first transmission mechanism turns a first steering wheel in accordance with the movement of the first nut,
the first motor actuator is a first electric motor that applies a rotational force to the first output shaft,
the second steering mechanism includes a second ball nut type steering unit and a second motor actuator,
the second ball nut type steering unit includes a second output shaft, a second ball screw, a second nut, and a second transmission mechanism,
the second output shaft is rotatable about a rotational axis of the second output shaft,
the second ball screw drives the second nut so that the second nut moves in the direction of the rotation axis of the second output shaft in accordance with the rotation of the second output shaft,
the second transmission mechanism steers a second steering wheel in accordance with the movement of the second nut,
the second motor actuator is a second electric motor that applies a rotational force to the second output shaft,
the coupling member couples the first transmission mechanism and the second transmission mechanism so that the first transmission mechanism and the second transmission mechanism can be interlocked with each other.
2. Steering device according to claim 1,
the steering device includes a control device that controls driving of the first motor actuator and the second motor actuator,
the control device controls driving of the first motor actuator and the second motor actuator so that a torque of the second motor actuator is larger than a torque of the first motor actuator when rotating the second motor actuator in the same direction as a steering direction of the first steerable wheels and the second steerable wheels.
3. Steering device according to claim 2,
the control device controls the drive of the first motor actuator so that the first steerable wheels maintain a steering angle when rotating the second motor actuator in the same direction as the steering direction of the first steerable wheels and the second steerable wheels.
4. Steering device according to claim 3,
the control device controls the drive of the first motor actuator so that the first steerable wheels maintain a steering angle when the second motor actuator is rotated in the same direction as the steering direction of the second steerable wheels at or above a predetermined vehicle speed.
5. Steering device according to claim 3,
the control device controls the driving of the first motor actuator so as to suppress disturbance from a road surface when rotating the second motor actuator in the same direction as the steering direction of the second steered wheels.
6. Steering device according to claim 5,
the second output shaft is connected with a steering wheel.
7. Steering device according to claim 6,
the second steering mechanism includes an input shaft, a torsion bar, a first angle sensor, and a second angle sensor,
the input shaft is connected with the steering wheel,
the torsion bar is disposed between the input shaft and the second output shaft,
the first angle sensor detects an angle of the input shaft,
the second angle sensor detects an angle of the second output shaft,
the control device determines that there is a disturbance from a road surface when the phase of the output signal of the second angle sensor is earlier than the phase of the output signal of the first angle sensor, and controls the driving of the first motor actuator so as to suppress the disturbance from the road surface when the second motor actuator is rotated in the same direction as the steering direction of the second steered wheel.
8. Steering device according to claim 1,
the steering device includes a control device that controls driving of the first motor actuator and the second motor actuator,
the second output shaft is connected with a steering wheel,
the control device controls driving of the second motor actuator prior to the first motor actuator.
9. Steering device according to claim 1,
the first and second ball nut steering units have no hydraulic circuit.
10. Steering device according to claim 1,
the first steering mechanism has a first reduction mechanism provided between the first output shaft and the first motor actuator,
the second steering mechanism has a second reduction mechanism disposed between the second output shaft and the second motor actuator.
11. Steering device according to claim 10,
the first reduction mechanism and the second reduction mechanism are each a combination of a worm and a worm wheel.
12. Steering device according to claim 1,
the first ball nut type steering unit includes a first sector gear that meshes with a first rack formed on the first nut,
the second ball-nut steering unit includes a second sector gear that meshes with a second rack formed on the second nut,
the first nut and the second nut have the same shape,
the first sector gear and the second sector gear have the same shape.
13. Steering device according to claim 1,
the steering device includes a control device that drives and controls the first motor actuator and the second motor actuator, and an input shaft, a torsion bar, and a torque sensor provided in the second steering mechanism,
the input shaft is connected with a steering wheel,
the torsion bar is disposed between the input shaft and the second output shaft,
the torque sensor detects a steering torque of the second steering mechanism based on a relative rotation angle of the input shaft and the second output shaft,
the control device controls driving of the first motor actuator and the second motor actuator in accordance with the steering torque.
14. Steering device according to claim 13,
the control device controls driving of both the first motor actuator and the second motor actuator in the same direction as the rotation direction of the steering wheel when the steering torque is equal to or greater than a predetermined value.
15. Steering device according to claim 1,
the second output shaft is connected with the steering column,
the second motor actuator is provided to the steering column and applies a steering force to the steering column.
16. Steering device according to claim 1,
the steering device includes a first control device that drives and controls the first motor actuator and a second control device that drives and controls the second motor actuator,
the first control device includes a first microcomputer for calculating a command signal to be output to the first motor actuator,
the second control device includes a second microcomputer that calculates a command signal to be output to the second motor actuator.
17. Steering device according to claim 16,
when one of the first motor actuator and the second motor actuator fails, the other motor actuator continues to be driven and controlled.
18. Steering device according to claim 16,
when one of the first microcomputer and the second microcomputer fails, the other microcomputer continues to be drive-controlled.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2017-161985 | 2017-08-25 | ||
| JP2017161985A JP6839632B2 (en) | 2017-08-25 | 2017-08-25 | Steering device |
| PCT/JP2018/028002 WO2019039183A1 (en) | 2017-08-25 | 2018-07-26 | Steering device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN111051183A true CN111051183A (en) | 2020-04-21 |
Family
ID=65438729
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201880050831.6A Pending CN111051183A (en) | 2017-08-25 | 2018-07-26 | Steering device |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JP6839632B2 (en) |
| CN (1) | CN111051183A (en) |
| DE (1) | DE112018004711T5 (en) |
| WO (1) | WO2019039183A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111516751A (en) * | 2020-05-15 | 2020-08-11 | 新昌县镇辉机械厂 | New energy automobile turns to device |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP7314703B2 (en) * | 2019-08-08 | 2023-07-26 | 日本精工株式会社 | vehicle steering system |
| JP7211324B2 (en) * | 2019-10-08 | 2023-01-24 | トヨタ自動車株式会社 | vehicle steering device |
| JP7317695B2 (en) | 2019-12-26 | 2023-07-31 | トヨタ自動車株式会社 | steering device |
| JP7520684B2 (en) | 2020-10-20 | 2024-07-23 | 日本精工株式会社 | Vehicle steering device |
| DE102021205875A1 (en) | 2021-06-10 | 2022-12-15 | Zf Friedrichshafen Ag | Steering gear device for a motor vehicle |
| US20230052313A1 (en) * | 2021-08-13 | 2023-02-16 | China Automotive Systems, Inc. | Electric steering assemblies for commercial vehicles |
| US20230142494A1 (en) * | 2021-11-08 | 2023-05-11 | Zf Active Safety And Electronics Us Llc | Apparatus for use in turning steerable vehicle wheels |
| WO2024047712A1 (en) * | 2022-08-29 | 2024-03-07 | 株式会社ジェイテクト | Steering device |
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Also Published As
| Publication number | Publication date |
|---|---|
| JP6839632B2 (en) | 2021-03-10 |
| DE112018004711T5 (en) | 2020-06-18 |
| WO2019039183A1 (en) | 2019-02-28 |
| JP2019038383A (en) | 2019-03-14 |
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