JP2010023561A - Vehicular steering device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicular steering device which is easily assembled and easily adaptable to various kinds of specifications. <P>SOLUTION: The rotation of first and second electric motors 161, 162 for steering assist is reduced by a first reduction gear mechanism 17 and a second reduction gear mechanism 18, and transmitted to a steering mechanism A. Driving gears 211, 212 accompanying rotary shafts 20 of the electric motors 161, 162 are engaged with a common driven gear 22. The rotation of the driven gear 22 is transmitted to a worm shaft 23 of the second reduction gear mechanism 18. A sub assembly SA includes a plurality of electric motors 161, 162, the first reduction gear mechanism 17 and a housing 19 for housing the electric motors and the first reduction gear mechanism. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a vehicle steering apparatus.

As a vehicle steering device, there has been proposed an electric power steering device that assists steering by applying the rotational force of a plurality of electric motors to a steering mechanism via a clutch and a speed reduction mechanism for each electric motor (for example, Patent Documents). 1).
JP-A-8-258728

However, when a plurality of motors are used, it takes time to assemble. Further, it cannot easily cope with various specifications required for the electric power steering apparatus.
The present invention has been made in view of the above problems, and an object of the present invention is to provide a vehicle steering apparatus that can be easily assembled and can easily cope with various specifications.

  In order to solve the above problems, the present invention provides an actuator (161, 162,...) For generating a steering force and a first speed reduction mechanism (17; 17A; 17B; 17C; 17D; connected to the actuator). 17E), a second reduction mechanism (18) connected to the first reduction mechanism, and a steering mechanism (A) connected to the second reduction mechanism, the actuator and the first The sub-assembly (SA; SA1) including the speed reduction mechanism is configured.

  In the present invention, since the actuator and the first reduction mechanism are unitized, for example, the specification of the unit can be easily changed by changing the reduction ratio of the first reduction mechanism by using the actuator in common. . Therefore, the present invention can be easily applied to a vehicle steering apparatus having various characteristics. Moreover, since the actuator and the first speed reduction mechanism can be assembled in advance as a subassembly, the assemblability is good.

  The first reduction mechanism includes a drive member (211, 212,..., 811, 812) and a driven member (22; 221, 222,..., 82), and a rotating shaft ( 20) and the support shaft (32; 84) of the driven member may be parallel to each other (claim 2). In this case, since the drive member and the driven member can be arranged at the same position with respect to the axial direction of the rotating shaft of the electric motor, the subassembly can be reduced in size with respect to the axial direction of the rotating shaft of the electric motor. The vehicle steering device can be reduced in size.

  Further, the driving member and the driven member of the first speed reduction mechanism include gears (211, 212, 22; 211, 221, 212, 222;...) Meshed with each other, and the gear includes spur teeth, mountain teeth, It may be a helical tooth (Claim 3). In this case, since gear transmission is used, power transmission is reliable. In particular, when a helical tooth is used, the meshing rate of the tooth can be increased, which is preferable for transmitting a high output.

  The actuator includes a plurality of electric motors (161, 162,...), A plurality of driving members of the first reduction mechanism are provided, and each driving member of the first reduction mechanism is a corresponding electric motor. There is a case where each of the rotating shafts is connected to the driven member of the first speed reduction mechanism so as to be capable of transmission (Claim 4). In this case, a plurality of motors can be arranged side by side, and each drive member and driven member connected to the rotation shaft of the corresponding electric motor can be arranged at the same position with respect to the axial direction of the rotation shaft. Therefore, the subassembly can be made smaller with respect to the axial direction of the rotating shaft of the electric motor, and thus the vehicle steering apparatus can be made smaller.

  Further, the driven member includes two helical gears (221, 222) connected coaxially, and the helical direction (X1, X2) of the two helical gears may be different from each other. (Claim 5). In this case, the axial components (thrust forces) of the driving reaction forces acting on the two helical teeth work in opposite directions to cancel each other. As a result, it is possible to suppress a reduction in transmission efficiency of the gear caused by the thrust force, particularly at high speed rotation. That is, the transmission efficiency of the first reduction mechanism can be improved.

Further, the drive member and the driven member may be connected to each other via an endless belt (83) (claim 6). In this case, since the degree of freedom in handling the endless belt is high, the degree of freedom in installing the drive member and the driven member can be increased. As a result, it becomes possible to install this vehicle steering apparatus in a narrow space.
In addition, a plurality of electric motors as the actuators are provided, a plurality of drive members of the first reduction mechanism are provided, and each drive member is connected to a rotation shaft of a corresponding electric motor so as to be able to rotate together. The drive member may include a drive member (811, 814) inscribed in the endless belt and a drive member (812, 813) in contact with the endless belt (claim 7). In this case, a tension is applied to the endless belt so that the driving member circumscribing the endless belt and the inscribed driving member press the endless belt against the other driving members. Therefore, there is no need to provide a separate tensioner, and the structure can be simplified.

Moreover, a rotation angle detection device (74) for detecting the rotation angle of the driven member may be provided (claim 8). Since the rotation angle of the driven member rotating in conjunction with the rotation shaft of the electric motor is detected, the conventionally used rotation angle detection device in the electric motor can be eliminated.
The rotation angle detector (74B) that detects the rotation angle of the rotation shaft of any one of the plurality of electric motors, or any one of the driving member and the driven member of the first reduction mechanism. There may be provided any one of the rotation angle detection devices (74A; 74) for detecting the rotation angle. In this case, when a plurality of electric motors are used, the rotation angle of each electric motor is detected by detecting the rotation angle of any one electric motor, any one drive member, or any one driven member. Detection can be substituted. Therefore, the structure can be greatly simplified.

Further, there may be provided an elastic member (56, 57) that elastically receives a thrust force acting on the driven member (claim 10). In this case, it is possible to suppress a reduction in gear transmission efficiency due to the thrust force. That is, the transmission efficiency of the first reduction mechanism can be improved.
In the above description, the alphanumeric characters in parentheses represent reference numerals of corresponding components in the embodiments described later, but the scope of the claims is not limited by these reference numerals.

Preferred embodiments of the present invention will be described with reference to the accompanying drawings.
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a schematic view schematically showing a configuration of an electric power steering apparatus as a vehicle steering apparatus according to an embodiment of the present invention.
Referring to FIG. 1, an electric power steering device 1 includes a steering shaft 3 connected to a steering member 2 such as a steering wheel, an intermediate shaft 5 connected to the steering shaft 3 via a universal joint 4, As a steered shaft extending in the left-right direction of an automobile, having a pinion shaft 7 connected to the shaft 5 via a universal joint 6 and rack teeth 8a meshing with pinion teeth 7a provided in the vicinity of the end of the pinion shaft 7 Rack bar 8. The pinion shaft 7 and the rack bar 8 constitute a steering mechanism A composed of a rack and pinion mechanism.

The rack bar 8 is supported in a housing 9 fixed to the vehicle body so as to be capable of linear reciprocation through a plurality of bearings (not shown). Both end portions of the rack bar 8 protrude to both sides of the housing 9, and tie rods 10 are coupled to the respective end portions. Each tie rod 10 is connected to a corresponding steered wheel 11 via a corresponding knuckle arm (not shown).
When the steering member 2 is operated and the steering shaft 3 is rotated, this rotation is converted into a linear motion of the rack bar 8 along the left-right direction of the automobile by the pinion teeth 7a and the rack teeth 8a. Thereby, the turning of the steered wheel 11 is achieved.

The steering shaft 3 is divided into an input-side upper shaft 3 a that is continuous with the steering member 2 and an output-side lower shaft 3 b that is continuous with the pinion shaft 7. These upper and lower shafts 3 a and 3 b are connected via a torsion bar 12. Are connected to each other so as to be relatively rotatable on the same axis.
A torque sensor 13 is provided for detecting a steering torque based on the amount of relative rotational displacement between the upper and lower shafts 3a, 3b via the torsion bar 12, and the torque detection result of the torque sensor 13 is obtained from an ECU (Electronic Control Unit: electronic Control unit) 14. In the ECU 14, first and second electric motors 161 as actuators for generating a steering force (a steering assist force in the present embodiment) based on a torque detection result, a vehicle speed detection result given from the vehicle speed sensor 15, and the like. , 162 are controlled.

The output rotations of the first and second electric motors 161 and 162 are decelerated via the first reduction mechanism 17 and the second reduction mechanism 18 as transmission devices and transmitted to the pinion shaft 7, and the straight line of the rack bar 8 It is converted into motion and steering is assisted.
A single unit that includes first and second electric motors 161 and 162, a first reduction mechanism 17, and a housing 19 that houses the first and second electric motors 161 and 162 and the first reduction mechanism 17. A sub-assembly SA as a unit is configured.

The first speed reduction mechanism 17 is a drive gear 211, 212 as a drive member connected to the rotary shaft 20 of each of the electric motors 161, 162 so as to be able to rotate together, and a driven member meshing with these drive gears 211, 212. The following driven gear 22 is provided.
The second speed reduction mechanism 18 is engaged with the worm shaft 23 that is rotationally driven by the first and second electric motors 161 and 162 via the first speed reduction mechanism 17, and meshes with the worm shaft 23 and lowers the steering shaft 3. A worm wheel 24 connected to the shaft 3b is rotatably provided. That is, the second reduction mechanism 18 is constituted by a worm gear mechanism.

Referring to FIG. 2, the subassembly SA includes a first support plate 25 and a second support plate 26 that face each other with a predetermined interval. The first support plate 25 is fastened to a gear housing 27 that houses the second reduction mechanism 18 by using, for example, a fixing screw 28.
A plurality of cylindrical spacers 29 are interposed between the first support plate 25 and the second support plate 26 to regulate the distance between the support plates 25 and 26. The first support plate 25 and the second support plate 26 are fixed to each other using a fixing screw 30 inserted through the spacer 29. For example, the fixing screw 30 inserted through the screw insertion hole of the second support plate 26 is screwed into the screw hole 31 formed in the first support plate 25, so that the spacer 29 is interposed between the support plates 25 and 26. As a result, both support plates 25 and 26 are fixed to each other.

  A support shaft 32 that rotates together with the driven gear 22 of the first speed reduction mechanism 17 is provided. On the other hand, the first and second support plates 25 and 26 are respectively formed with first and second support holes 33 and 34 arranged on the same axis. The support shaft 32 of the driven gear 22 is rotatably supported by a first bearing 35 held in the first support hole 33 and has a second bearing 36 held in the second support hole 34. It is supported so that it can rotate through.

The second support plate 26 has a first surface 37 that faces the first support plate 25 and a second surface 38 that is opposite to the first surface 37. A motor housing 39 of each electric motor 161, 162 is fixed to the second surface 38 of the second support plate 26.
Specifically, the fixing screw screwed into the screw hole 42 of the end wall 41 of the motor housing 39 from the first surface 37 side of the second support plate 26 through the screw insertion hole 40 of the second support plate 26. The motor housing 39 is fixed to the second support plate 26 using 43.

  The rotating shaft 20 protrudes from the end wall 41 of the motor housing 39 of each electric motor 161, 162, and the rotating shaft 20 is inserted through the insertion hole 44 formed in the second support plate 26, and the first and It extends between the second support plates 25 and 26. Drive gears 211 and 212 that are respectively attached to the end portions of the rotary shafts 20 of the electric motors 161 and 162 mesh with the common driven gear 22.

As shown in FIG. 3, the drive gears 211 and 212 attached to the respective rotary shafts 20 of the first and second electric motors 161 and 162 are disposed at positions facing each other with the driven gear 22 interposed therebetween.
Referring to FIG. 2, the housing 19 that houses the first and second electric motors 161 and 162 and the first speed reduction mechanism 17 is configured by combining a first support plate 25 and a cylindrical cover housing 45. The housing space is partitioned inside. The cover housing 45 includes a cylindrical portion 46 that is open at one end 46 a and surrounds the second support plate 26, and an end wall 47 that closes the other end 46 b of the cylindrical portion 46.

As shown in FIG. 4, a mounting flange 48 extending radially outward from a part in the circumferential direction of one end 46 a of the cylindrical portion 46 of the cover housing 45 is provided. The cover housing 45 is fixed to the first support plate 25 by using a fixing screw 50 inserted through the mounting flange 48 and screwed into the screw hole 49 of the first support plate 25.
Referring to FIG. 5, the support shaft 32 is provided so as to be able to rotate along with the driven gear 22 and to move along the axial direction. The support shaft 32 is supported in a floating manner in the axial direction. Specifically, the first bearing 35 includes an outer ring 51 press-fitted into the first support hole 33 of the first support plate 25, an inner ring 52 in which the support shaft 32 is loosely fitted, and an outer ring 51. And a ball bearing having a rolling element 53 interposed between the inner rings 52.

The second bearing 36 is a slide bearing such as a slide metal that is press-fitted and held in the second support hole 34 of the second support plate 26. However, a rolling bearing such as a ball bearing may be used as the second bearing 36.
On the outer periphery of the support shaft 32, annular first and second pressing plates 54 and 55 are attached that are capable of moving in the axial direction of the support shaft 32. The first pressing plate 54 is disposed between the first bearing 35 and the driven gear 22, and is made of, for example, rubber between the end surface 52 a of the inner ring 52 of the first bearing 35 and the first pressing plate 54. The annular elastic member 56 is interposed in a compressed state.

The second pressing plate 55 is disposed between the second bearing 36 and the driven gear 22, and an annular elastic member is provided between the end surface 36 a of the second bearing 36 and the second pressing plate 55. 57 is interposed in a compressed state. The support shaft 32 is elastically supported by both elastic members 56 and 57 in both axial directions.
Therefore, since the thrust force acting on the driven gear 22 can be elastically received by the elastic members 56 and 57, it is possible to suppress a decrease in transmission efficiency of the drive gears 211 and 212 and the driven gear 22 due to the thrust force. In addition, vibrations generated between the support shaft 32 and the support plates 25 and 26 due to the thrust force can be suppressed.

  In other words, since a plurality of small electric motors 161 and 162 are used and the first reduction mechanism 17 is set to a high reduction ratio, when rotating at high speed by sudden steering or the like, due to variations in assembly accuracy of each component, etc. There is a possibility that a high thrust force is generated in a direction parallel to the rotating shaft 20 of the electric motors 161 and 162. If the rotating shaft 20 is supported by a ball bearing in the electric motors 161 and 162, the number of parts may increase or abnormal noise may occur. In contrast, in the present embodiment, the elastic members 56 and 57 can absorb the thrust force, thereby suppressing a reduction in transmission efficiency, and supporting shaft 32. And vibrations generated between the support plates 25 and 26 can be suppressed.

Referring again to FIG. 2, the worm shaft 23 is arranged coaxially with the support shaft 32 of the driven gear 22 as the output shaft of the first speed reduction mechanism 17. The worm shaft 23 has first and second end portions 23a and 23b that are separated from each other in the axial length direction, and has a tooth portion 23c at an intermediate portion between the first and second end portions 23a and 23b.
The worm wheel 24 is coupled to an intermediate portion in the axial direction of the lower shaft 3b of the steering shaft 3 so as to be able to rotate together and not to move in the axial direction. The worm wheel 24 includes an annular core bar 58 that is coupled to the lower shaft 3b so as to be integrally rotatable, and a synthetic resin member 59 that surrounds the core bar 58 and has teeth 59a formed on the outer periphery. The core metal 58 is inserted into a mold when the synthetic resin member 59 is molded with resin, for example.

An output shaft of the first reduction mechanism 17, a support shaft 32 of the driven gear 22, and the worm shaft 2 3 are arranged coaxially, the support shaft 32 and the worm shaft 23, interposed between them The joint 60 is coaxially connected so as to be able to transmit power. The joint 60 is interposed between the input member 61 and the output member 62, the annular input member 61 that rotates along with the support shaft 32, the annular output member 62 that rotates along with the worm shaft 23, and the input member 61 and the output member 62. And an annular elastic member 63 that couples the output member 62 so that power can be transmitted.

The first and second end portions 23a and 23b of the worm shaft 23 are rotatably supported by the gear housing 27 via corresponding third and fourth bearings 64 and 65, respectively. The third and fourth bearings 64 and 65 are ball bearings, for example.
Inner rings 66 and 67 of the third and fourth bearings 64 and 65 are fitted to the first and second end portions 23a and 23b of the worm shaft 23 so as to be integrally rotatable. The inner rings 66 and 67 are in contact with the corresponding positioning step portions 23d and 23e of the worm shaft 23 that are opposite to each other. The outer rings 68 and 69 of the third and fourth bearings 66 and 67 are held in the corresponding bearing holding holes 70 and 71 of the gear housing 27.

  An annular fixing member 73 is screwed into the screw portion 72 adjacent to the bearing holding hole 70, and the fixing member 73 presses the end surface of the outer ring 68 of the third bearing 64. The pressing force by the fixing member 73 is caused by the bottom of the bearing holding hole 71 via the inner ring 66 of the third bearing 64, the positioning step portions 23d and 23e of the worm shaft 23, the inner ring 67 and the outer ring 69 of the fourth bearing 65. I have received it. As a result, preload is applied to the third bearing 64 and the fourth bearing 65.

  Further, the sub-assembly SA is provided with a rotation angle sensor 74 as a rotation angle detection device that detects the rotation angle of the driven gear 22. The rotation angle sensor 74 includes, for example, an annular movable portion 75 that is attached to the end face of the driven gear 22 so as to be able to rotate along with the stationary gear 22, and a fixed portion 76 that is fixed to the first support plate 25 so as to face the movable portion 75. It has. The fixed unit 76 is provided with a detection unit for detecting the rotational displacement of the movable unit 75. The output signal of the rotation angle sensor 74 is given to the ECU 14.

  The rotation angle of the driven gear 22 has a certain correlation based on the gear ratio of the drive gears 211 and 212 and the driven gear 22 with respect to the rotation angle of the rotation shaft 20 of each of the electric motors 161 and 162. Therefore, the ECU 14 calculates the rotation angle of the rotating shaft 20 of each of the electric motors 161 and 162 based on the rotation angle of the driven gear 22 and the gear ratio detected by the rotation angle sensor 74. Therefore, the electric motors 161 and 162 do not need to be provided with a rotation angle sensor such as a resolver that is normally provided, and the structure can be simplified.

Since the output of the rotation angle sensor 74 that detects the rotation angle of the driven gear 22 is used to detect the rotation angle of the electric motors 161 and 162, the rotation angle is detected before the second deceleration mechanism 18 decelerates. Therefore, for example, when the vehicle steering apparatus 1 is applied to a parking assistance system, the steering angle can be accurately controlled during parking assistance.
According to the present embodiment, the first and second electric motors 161 and 162, the first speed reduction mechanism 17, the housing 19 that accommodates these, and the like are unitized as a subassembly SA. Therefore, for example, the specification of the unit can be easily changed by making the electric motors 161 and 162 common and changing the reduction ratio of the first reduction mechanism 17. Thereby, the unit can be easily applied to the vehicle steering apparatus 1 having various characteristics.

By using a common electric motor with a high manufacturing cost, the overall cost when manufacturing various units can be reduced. Since the size of the electric motor can be reduced, the weight of the subassembly SA as a whole can be reduced, and the weight of the vehicle steering device 1 as a whole can be reduced.
In particular, by combining the small and high-rotation type electric motors 161 and 162 with the first reduction mechanism 17 having a high reduction ratio, a high output can be obtained even in a small size. In addition, since the plurality of electric motors 161 and 162, the first speed reduction mechanism 17 and the like can be assembled in advance as the subassembly SA, the assemblability is good.

  Further, since the first speed reduction mechanism 17 includes the drive gears 211 and 212 and the driven gear 22 and the rotating shaft 20 of the electric motors 161 and 162 and the support shaft 32 of the driven gear 22 are parallel, the following advantages are obtained. . That is, since the drive gears 211 and 212 and the driven gear 22 can be arranged at the same position with respect to the axial direction of the rotating shaft 20 of each electric motor 161 and 162, the subassembly SA can be reduced in size with respect to the axial direction of the rotating shaft 20. As a result, the vehicle steering apparatus 1 can be reduced in size.

  Since the transmission system of the first speed reduction mechanism 17 is the gear transmission using the drive gears 211 and 212 and the driven gear 22 that are meshed with each other, the power transmission is reliable. The drive gears 211 and 212 and the driven gear 22 may be spur gears meshing with each other, angle gears meshing with each other, or helical gears meshing with each other. In particular, when a helical tooth is used, the meshing rate of the tooth can be increased, which is preferable for transmitting a high output.

  In addition, a plurality of electric motors 161 and 162 are provided as actuators for generating a steering force, and each of the plurality of drive gears 211 and 212 of the first reduction mechanism 17 is connected to the rotating shaft 20 of the corresponding electric motor 161 and 162. Each is connected and connected to the driven gear 22 so as to be able to transmit. Therefore, there are the following advantages. That is, a plurality of electric motors 161 and 162 are arranged side by side, and the driving gears 211 and 212 and the driven gear 22 connected to the rotating shafts 20 of the corresponding electric motors 161 and 162 are arranged in the axial direction of the rotating shaft 20. Can be placed at the same position. Therefore, the subassembly SA can be further reduced in size with respect to the axial direction of the rotating shaft 20 of the electric motors 161 and 162, and the vehicle steering apparatus 1 can be further reduced in size.

  Further, in the present embodiment, the rotation angle sensor built in each of the electric motors 161 and 162 is eliminated, and the rotation angle sensor 74 for detecting the rotation angle of the driven gear 22 is provided. You may make it provide the rotation angle sensor which detects the rotation angle of one drive gear 211,212. Instead of these, a rotation angle sensor that detects the rotation angle of the rotating shaft 20 of any one of the electric motors 161 and 162 may be provided.

  Next, FIG. 6 shows another embodiment of the present invention. Referring to FIG. 6, the present embodiment is mainly different from the embodiment of FIG. 2 in the first reduction mechanism 17 of the embodiment of FIG. 2 in which the rotating shaft 20 of each electric motor 161, 162. The drive gears 211 and 212 connected to each other mesh with the common driven gear 22, whereas in the first reduction mechanism 17 </ b> A of the embodiment of FIG. The first driven gear 221 and the second driven gear 222 are provided, the first driven gear 221 meshes with the drive gear 211, and the second driven gear 222 meshes with the drive gear 212.

The first driven gear 221 and the second driven gear 222 are both helical gears, and the tooth driven direction X1 of the first driven gear 221 and the tooth driven direction X2 of the second driven gear 222 are both. Are different from each other. Specifically, the tooth trace directions X1 and X2 are inclined in directions opposite to each other with respect to the axial direction of the support shaft 32.
In this embodiment, the pressing plates 54 and 55 and the elastic members 56 and 57 provided in the embodiment of FIG. 5 are omitted. In the present embodiment, the same components as those in the embodiment of FIG. 2 are denoted by the same reference numerals.

  According to the present embodiment, the axial components (thrust forces) of the driving reaction force acting on the first driven gear 221 and the second driven gear 222 are canceled in the opposite directions. As a result, it is possible to suppress a decrease in transmission efficiency of the first speed reduction mechanism 17A caused by the thrust force, particularly during high-speed rotation. That is, the transmission efficiency of the first reduction mechanism 17A can be improved.

  When a plurality of electric motors 161 and 162 are combined, the number of gear meshing portions for deceleration increases. For this reason, in order to suppress abnormal noise and to suppress a decrease in transmission efficiency, high assembly accuracy between the gears is required, and as a result, the defect rate of the product may increase. On the other hand, when a combination of helical gears is used, the effect of suppressing the thrust force can be expected as described above, so that it is not necessary to excessively increase the assembly accuracy.

  In the embodiment of FIG. 2, the two electric motors 161 and 162 are used as the actuator, but the present invention is not limited to this. For example, as shown in the first reduction mechanism 17B in FIGS. 7A and 7B, first, second, and third electric motors 161, 162, and 163 may be used. Also in this case, the drive gears 211, 212, and 213 respectively connected to the rotary shafts 20 of the electric motors 161 to 163 are arranged at equal intervals in the circumferential direction of the driven gear 22.

When three electric motors 161 to 163 are provided, when an abnormality occurs in any one of the three electric motors 161 to 163 (that is, when a failure occurs), the remaining two normal electric motors It is preferable to secure the necessary steering by using.
Specifically, as shown in mode 1 of Table 1 below, during normal operation, the first electric motor 161 is used for left and right steering, and the remaining second electric motor 162 is used only for right steering. The third electric motor 163 may be used only for left steering. In this case, two electric motors are used in each of the left steering and the right steering, and a sufficient output for each steering can be obtained.

  Then, when a failure occurs in any one of the first, second and third electric motors 161 to 163, modes 2 and 3 shown in Table 1 below are alternatively executed, or mode 4 , 5 may be executed alternatively, or modes 6 and 7 may be executed alternatively.

Referring to Table 1, when a failure occurs in first electric motor 161 used for left and right steering, mode 2 control may be performed. You may make it implement 3 control.
In mode 2, the drive control for the first electric motor 161 is stopped, and the second and third electric motors 162 and 163 that are functioning normally are steered to the right in the same manner as in the normal state. And left steering respectively. However, during a failure, the output for steering is half of the normal output.

In mode 3, the second and third electric motors 162 and 163 are stopped so that the drive control for the first electric motor 161 is stopped, and both the second and third electric motors 162 and 163 contribute to both left and right steering. The drive control for the third electric motors 162 and 163 is switched.
Next, when a failure occurs in the second electric motor 162 used for the right steering, the control of the mode 4 may be performed, or the control of the mode 5 is performed instead of the mode 4. You may do it.

  In mode 4, the drive control for the second electric motor 162 is stopped, and the first electric motor 161 and the third electric motor 163 that are functioning normally are caused to function in the same manner as in a normal state. That is, the first electric motor 161 is caused to contribute to left steering and right steering. Further, the third electric motor 163 is allowed to contribute only to left steering. However, in mode 4, the output for the right steering at the time of a failure is half of that at the normal time.

  In mode 5, the drive control for the second electric motor 162 is stopped, and the normally functioning first electric motor 161 is caused to contribute to the left steering and the right steering as in the normal case. Further, the drive control for the third electric motor 163 is switched so that the third electric motor 163 that contributes only to the left steering at the normal time contributes to both the left steering and the right steering.

Next, when a failure occurs in the third electric motor 163 used for left steering, mode 6 control may be performed, or mode 7 control is performed instead of mode 6. You may do it.
In mode 6, the drive control for the third electric motor 163 is stopped, and the normally functioning first electric motor 161 and second electric motor 162 are caused to function in the same manner as in normal times. That is, the first electric motor 161 is caused to contribute to left steering and right steering. Further, the second electric motor 162 is allowed to contribute only to the right steering. However, in mode 6, the output for left steering at the time of failure is half of that at normal time.

  In mode 7, the drive control for the third electric motor 163 is stopped, and the normally functioning first electric motor 161 is caused to contribute to the left steering and the right steering as in the normal case. Further, the drive control for the second electric motor 162 is switched so that the second electric motor 162 that contributes only to the right steering at the normal time contributes to both the left steering and the right steering.

Further, as shown in FIGS. 8A and 8B, four electric motors 161, 162, 163, and 164 may be used. Also in this case, the drive gears 211, 212, 213, 214 connected to the rotary shafts 20 of the electric motors 161, 162, 163, 164 are arranged at equal intervals in the circumferential direction of the driven gear 22. Become.
When four electric motors 161 to 164 are provided, as shown in mode 1 in Table 2 below, the first and third electric motors 161 and 163 are used only for right steering during normal operation. The fourth electric motors 162 and 164 may be used only for left steering. In this case, two electric motors are used in each of the left steering and the right steering, and a sufficient output for each steering can be obtained.

  And when abnormality generate | occur | produces in any one electric motor among the four electric motors 161-164, it is preferable to ensure required steering using the remaining three normal electric motors. For example, as shown in Table 2, when an abnormality occurs in the first electric motor 161, as shown in Mode 2 of Table 2, the drive control of the first electric motor 161 is stopped, and the second, second, The third and fourth electric motors 162, 163, and 164 contribute to only left steering, only right steering, and only left steering, respectively, as in the normal case. However, in this case, the right steering output at the time of failure is half of the normal output.

  Further, instead of mode 2 in Table 2, mode 3 in Table 2 may be executed. In mode 3 of Table 2, the drive control of the first electric motor 161 is stopped. Further, the drive control for the second electric motor 162 is switched so that the second electric motor 162 that contributes only to the left steering at the normal time contributes to the left steering and the right steering. Further, the third and fourth electric motors 163 and 164 are caused to contribute only to the right steering and only to the left steering, respectively, as in the normal case.

  On the other hand, when an abnormality occurs in any two of the four electric motors 161 to 164, it is preferable to ensure the necessary steering by using the remaining two normal electric motors. For example, as shown in Table 2, when an abnormality occurs in the first and second electric motors 161 and 162, as shown in mode 4 of Table 2, the drive control of the first and second electric motors 161 and 162 is performed. To stop. Further, the third and fourth electric motors 163 and 164 are caused to contribute only to the right steering and only to the left steering, respectively, as in the normal case. However, the steering output during a failure is half of the normal output.

  Further, instead of mode 4 in Table 2, mode 5 in Table 2 may be executed. In mode 5 of Table 2, the drive control of the first and second electric motors 161 and 162 is stopped. In addition, the third and fourth electric motors 163, 164, which contributed to only one side of the steering at the normal time, contribute to both the left steering and the right steering. The drive control for the motors 163 and 164 is switched. In this case, the same steering output as that in the normal state can be obtained during a failure.

  When four electric motors 161 to 164 are provided, as shown in mode 1 in Table 3 below, the first electric motor 161 contributes to left steering and right steering during normal operation, and the second In some cases, the electric motor 162 contributes only to the right steering, the third electric motor 163 contributes only to the left steering, and the fourth electric motor 164 is stopped. That is, the fourth electric motor 164 is kept waiting for a failure.

  And when abnormality generate | occur | produces in the 1st electric motor 161, as shown in the mode 2 of Table 3, the drive control of the 1st electric motor 161 is stopped. Further, the second and third electric motors 162 and 163 are caused to contribute only to the right steering and only to the left steering, respectively, as in the normal case. Further, the fourth electric motor 164 is driven and controlled so that the fourth electric motor 164 that has been at rest in the normal state contributes to both left and right steering. In this case, it is possible to obtain the same steering output at the time of failure as at the normal time.

  When an abnormality occurs in the second electric motor 162, the drive control of the second electric motor 162 is stopped as shown in mode 3 in Table 3. Further, the first electric motor 161 is caused to contribute to the left steering and the right steering as in the normal case. Further, the third electric motor 163 is caused to contribute only to the left steering as in the normal case. In addition, the fourth electric motor 164 is driven and controlled so that the fourth electric motor 164 that has been at rest in the normal state contributes to the right steering. In this case, it is possible to obtain the same steering output at the time of failure as at the normal time.

  Further, when an abnormality occurs in the third electric motor 163, the drive control of the third electric motor 163 is stopped as shown in mode 4 in Table 3. Further, the first electric motor 161 is caused to contribute to the left steering and the right steering as in the normal case. Further, the second electric motor 162 is caused to contribute only to the right steering as in the normal case. In addition, the fourth electric motor 164 is driven and controlled so that the fourth electric motor 164 that has been at rest in the normal state contributes to left steering. In this case, it is possible to obtain the same steering output at the time of failure as at the normal time.

  In each of the above embodiments, the gear mechanism is used as the first reduction mechanism, but the present invention is not limited to this. For example, as shown in FIGS. 9A and 9B, a first reduction mechanism 17D composed of a belt / pulley mechanism may be used. If it explains in accordance with the case where four electric motors 161-164 are used, the drive pulley 811 as a drive member will be respectively set in the rotating shaft 20 of the 1st, 2nd, 3rd, and 4th electric motors 161-164. 812, 813 and 814 are attached so as to be able to rotate together. These drive pulleys 811 to 814 and a driven pulley 82 as a driven member are connected to each other through an endless belt 83 so as to be capable of transmission. A support shaft 84 that rotates together with the driven pulley 82 constitutes an output shaft of the first speed reduction mechanism 17D. Although not shown, the support shaft 84 of the driven pulley 82 is connected to the worm shaft of the second reduction mechanism via a joint.

The driving pulleys 811 and 814 and the driven pulley 82 connected to the rotary shaft 20 of the first and fourth electric motors 161 and 164 are inscribed in the endless belt 83, and the second and third electric motors 162 and 163 are inscribed. Driving pulleys 812 and 813 connected to the rotary shaft 20 circumscribe the endless belt 83.
In the present embodiment, since the degree of freedom of handling the endless belt 83 is high, the degree of freedom of installation of the drive pulleys 811 to 814 and the driven pulley 82 can be increased. As a result, the vehicle steering apparatus 1 can be installed in a narrow space.

Further, tension is applied to the endless belt 83 so that one of the drive pulleys 812 and 813 circumscribed with the endless belt 83 and the drive pulleys 811 and 814 inscribed with the endless belt 83 press the endless belt 83 against the other. become. Therefore, it is not necessary to separately provide a tensioner for the endless belt 83, and the structure can be simplified.
Next, FIGS. 10, 11 and 12 show still another embodiment of the present invention. As shown in FIG. 12, first and second electric motors 161 and 162 as a plurality of electric motors are provided. As shown in FIG. 10, the rotating shaft 20 of each of the electric motors 161 and 162 and a worm The shaft 23 is disposed in parallel, and a first speed reduction mechanism 17E is disposed between the rotating shaft 20 and the worm shaft 23.

The first and second electric motors 161 and 162, the first speed reduction mechanism 17E, the worm shaft 23, a part of the worm wheel 24, and the housing 19E that accommodates these sub-units as a single unit. An assembly SA1 is configured.
A motor housing 39 of each electric motor 161, 162 is fixed to the housing 19E. Further, the gear housing 27E that accommodates the remaining portion of the worm wheel 24 and the housing 19E have opposing plates 85 and 86 that face each other. Between the opposing plates 85 and 86, for example, the opposing plates 85 and 86 are coupled by a screw 88 so as to be relatively movable in the axial direction of the screw 88 with an elastic body 87 such as a rubber plate interposed. The housing 19E of the subassembly SA1 is elastically supported via the elastic body 87 by the gear housing 27E.

  Specifically, as the elastic body 87, a rubber material along the entire surface of the opposing plates 85 and 86 may be used, or an annular member surrounding each screw 88 may be used. In that case, as the elastic body 87, for example, an annular rubber plate as shown in FIG. 11 may be used, an O-ring may be used, or a spring washer may be used. A composite washer in which a rubber material is sandwiched between two metal washers may be used.

The housing 19E and the housing 27E may be fastened by using a fastening band wound around the housings 19E and 27E.
As shown in FIG. 11, the annular elastic body 87 is sandwiched between the opposing plate 85 of the gear housing 27E and the opposing plate 86 of the housing 19E, and is inserted into the screw insertion hole 89 of the opposing plate 85. A screw 88 is screwed into the screw hole 90 of the counter plate 86.

  Referring to FIG. 10 again, the first and second end portions 23a and 23b of the worm shaft 23 are rotatably supported by the first and second bearings 91 and 92 held by the housing 19E. . The electric motors 161 and 162 are so-called dual-axis motors, and one end 20 a and the other end 20 b of the rotating shaft 20 of each electric motor 161 and 162 protrude from the motor housing 39 in opposite directions.

  A drive gear 211 connected to the one end 20a of the rotating shaft 20 of each electric motor 161, 162 is rotatably connected to a driven gear 221 connected to the first end 23a of the worm shaft 23 so as to be able to rotate together. It is engaged. On the other hand, as shown in FIG. 12, the drive gear 212 connected to the other end 20 b of the rotating shaft 20 of each electric motor 161, 162 is rotatably connected to the second end 23 b of the worm shaft 23. It is meshed with a driven gear 222 that is rotatably connected.

That is, the first speed reduction mechanism 17E is configured to have two parallel transmission paths of a set of two drive gears 211 and a driven gear 221 and a set of two drive gears 212 and a driven gear 222. The reduction ratios of both sets are made equal to each other. However, any one of the sets may be abolished.
According to the present embodiment, the elastic body 87 is interposed between the opposing plates 85 and 86 of the gear housing 27E and the housing 19E of the subassembly SA1, and direct contact between the opposing plates 85 and 86 is avoided. So there are the following advantages. That is, vibrations from the housing 19E of the subassembly SA1 supporting the electric motors 161 and 162, the first speed reduction mechanism 17E and the worm shaft 23 to the gear housing 27E supporting the worm wheel 24 and the steering shaft 3 It is possible to prevent noise from being transmitted.

Further, the amount of backlash between the worm 23c and the worm wheel 24 can be adjusted and managed by setting the distance between the opposing plates 85 and 86 of the gear housing 27E and the housing 19E.
In addition, since the sub-assembly SA1 supporting the electric motors 161 and 162, the first speed reduction mechanism 17E, and the worm shaft 23 is elastically supported, the starting torque of the second speed reduction mechanism 18 when the steering operation is started. As a result, the steering feeling can be improved.

Further, since the power is transmitted to the worm shaft 23 via the driven gears 221 and 222 provided at both ends 23a and 23b of the worm shaft 23, the worm shaft 23 can be driven stably.
The present invention is not limited to the above-described embodiments. For example, when the driving gears 211 and 212 and the driven gear 22 are used as the driving member and the driven member as in the embodiment of FIG. Instead of the rotation angle sensor 74 for detecting the rotation angle of the drive gear 211, a rotation angle sensor 74A for detecting the rotation angle of any one of the drive gears 211, 212 may be provided as shown in FIG. Instead of the rotation angle sensor 74, a rotation angle sensor 74B for detecting the rotation angle of the rotating shaft 20 of any one of the electric motors 161 and 162 may be provided as shown in FIG.

Also in the embodiment of FIGS. 13 and 14, since the rotation angle is detected at the stage before the deceleration by the second deceleration mechanism 18, for example, when the vehicle steering apparatus 1 is applied to a parking assistance system. The steering angle can be accurately controlled during parking assistance.
9A, when the driving pulley and the driven pulley are adopted as the driving member and the driven member, the driven pulley 82 (if a plurality of driven pulleys are provided, A rotation angle sensor that detects the rotation angle of one of the driven pulleys), a rotation angle sensor that detects the rotation angle of any one of the drive pulleys 811 to 814, or the electric motor 161. A rotation angle sensor that detects the rotation angle of any one of ˜164 may be used.

It is a mimetic diagram showing a schematic structure of an electric power steering device as a vehicle steering device of one embodiment of the present invention. It is sectional drawing of the principal part of an electric power steering device. It is the schematic which shows the layout of an electric motor and a 1st reduction mechanism. It is sectional drawing of the principal part of the housing of a subassembly. It is sectional drawing of the support structure of a driven gear. It is sectional drawing of the principal part of the electric power steering device as a steering device for vehicles of another embodiment of this invention. An example using two driven gears is shown. It is the schematic of the 1st reduction mechanism and electric motor of another embodiment of this invention. An example using three electric motors is shown. FIG. 7B is a perspective view of the first reduction mechanism and electric motor of FIG. 7A. It is the schematic of the 1st reduction mechanism and electric motor of another embodiment of this invention. An example using four electric motors is shown. It is a perspective view of the 1st speed-reduction mechanism and electric motor of FIG. 8A. It is the schematic of the 1st reduction mechanism and electric motor of another embodiment of this invention. An example using four electric motors and an endless belt is shown. It is a perspective view of the 1st speed-reduction mechanism and electric motor of FIG. 9A. It is a schematic sectional drawing of the principal part of the electric power steering apparatus as a steering device for vehicles of further another embodiment of this invention. It is an enlarged view of the principal part of the electric power steering apparatus of FIG. It is typical sectional drawing which cut | disconnected the principal part of the electric power steering apparatus of FIG. 10 from another angle. It is sectional drawing of the principal part of the electric power steering apparatus as a steering device for vehicles of another embodiment of this invention. The example using the rotation angle sensor which detects the rotation angle of any one drive gear is shown. It is sectional drawing of the principal part of the electric power steering apparatus as a steering device for vehicles of another embodiment of this invention. The example using the rotation angle sensor which detects the rotation angle of the rotating shaft of any one electric motor is shown.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Electric power steering device (vehicle steering device), 2 ... Steering member, 3 ... Steering shaft, 5 ... Intermediate shaft, 7 ... Pinion shaft, 8 ... Rack bar, A ... Rack and pinion mechanism (steering mechanism), 11 ... steered wheel, 14 ... ECU, 161, 162, 163, 164 ... electric motor, 17, 17A, 17B, 17C, 17D, 17E ... first reduction mechanism, 18 ... second reduction mechanism, 19, 19E ... housing , SA, SA1 ... subassembly, 20 ... rotating shaft, 211, 212, 213, 214 ... drive gear (drive member), 22; 221, 222 ... driven gear (driven member), 23 ... worm shaft, 24 ... worm wheel 25 ... first support plate, 26 ... second support plate, 27, 27E ... gear housing, 32 ... support shaft, 35 ... first bearing, 36 ... second bearing, 39 Motor housing, 45 ... cover housing, 46 ... cylindrical portion, 47 ... end wall, 74, 74A, 74B ... rotation angle sensor (rotation angle detector), 811, 814 ... drive pulley (drive member inscribed in the endless belt) , 812, 813 ... Drive pulley (drive member circumscribing the endless belt), 82 ... Driven pulley (driven member), 83 ... Endless belt

Claims (10)

An actuator for generating a steering force; a first speed reduction mechanism connected to the actuator; a second speed reduction mechanism connected to the first speed reduction mechanism; and a second speed reduction mechanism connected to the second speed reduction mechanism A steering mechanism,
A vehicle steering apparatus comprising a subassembly including the actuator and the first speed reduction mechanism. In Claim 1, said 1st speed-reduction mechanism contains a drive member and a driven member,
A steering apparatus for a vehicle, wherein a rotating shaft of an electric motor as the actuator and a support shaft of the driven member are parallel to each other.   3. The vehicle according to claim 1, wherein the driving member and the driven member of the first speed reduction mechanism include gears meshed with each other, and the gears are spur teeth, angle teeth, or helical teeth. Steering device. The actuator according to claim 2 or 3, wherein the actuator includes a plurality of electric motors.
A plurality of drive members of the first reduction mechanism are provided;
Each of the drive members of the first reduction mechanism is connected to the rotation shaft of the corresponding electric motor, and is connected to the driven member of the first reduction mechanism so as to be capable of transmission. Steering device.   4. The vehicle steering apparatus according to claim 3, wherein the driven member includes two helical gears connected coaxially, and the helical directions of the two helical gears are different from each other.   3. The vehicle steering apparatus according to claim 2, wherein the driving member and the driven member are connected to each other through an endless belt so as to be able to transmit power. In claim 6, a plurality of electric motors as the actuator are provided,
A plurality of drive members of the first speed reduction mechanism are provided, and each drive member is connected to a corresponding rotation shaft of the electric motor so as to be able to rotate together.
The vehicle steering apparatus, wherein the plurality of drive members include a drive member inscribed in the endless belt and a drive member in contact with the endless belt.   8. The vehicle steering apparatus according to claim 1, further comprising a rotation angle detection device that detects a rotation angle of the driven member.   8. The rotation angle detection device for detecting a rotation angle of a rotation shaft of any one of the plurality of electric motors, or a driving member and a driven member of the first speed reduction mechanism according to claim 4 or 7. A vehicle steering apparatus comprising any one of rotation angle detection devices that detect one rotation angle.   The vehicle steering apparatus according to any one of claims 1 to 9, further comprising an elastic member that elastically receives a thrust force acting on the driven member.

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