JP2009073334A - Steering system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make it possible to secure smooth operation feeling of a steering wheel by mainly preventing the occurrence of rattling of gears by backlash. <P>SOLUTION: A controller 5 is structured so as to be capable of outputting control signals 57, 58 for preventing the rattling that can prevent the generation of the rattling by the backlash at two engagement portions 53, 54, by generating very small pre-load torque 51, 52, which rotates a primary gear 12 in the relative direction, to at least two sets of reaction force generation devices 8, 9 and by putting the primary gear 12 into a light rotation-restricting state. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a steering system.

  A vehicle such as an automobile is usually provided with a steering system. Such a steering system includes what is called a steer-by-wire system (see, for example, Patent Documents 1 and 2).

  In this steer-by-wire system, a steering device and a steering device are provided in a mechanically separated state, and the steering device and the steering device are controlled by a control device.

  The steering device described above includes at least a column shaft having a steering wheel and a reaction force generator.

  The steering device includes a direct drive type in which the column shaft and the reaction force generator are directly connected, and an indirect drive type in which the column shaft and the reaction force generation device are indirectly connected via a gear type reduction mechanism. Yes.

  Among these, it is known that the direct drive type has a drawback that the motor constituting the reaction force generating device is enlarged to achieve the required torque. On the other hand, it is known that the indirect drive type has an advantage that a large torque can be achieved by reducing the motor of the reaction force generating device by the reduction mechanism.

  In the indirect drive type, at least two reaction force generators are provided, the speed reduction mechanism has at least a primary gear attached to the column shaft, and at least two reaction force generators are primary. Some gears are configured to mesh directly or indirectly with at least two positions.

  According to such a configuration, when the steering device is operated, the control device detects this, sends a control signal to the steering device, and turns the steering device. At the same time, when the steering device is steered, the control device detects this and sends a control signal to the reaction force generation device of the steering device to generate a steering reaction force on the column shaft and the steering wheel of the steering device.

  At this time, by indirectly connecting the column shaft and the reaction force generator via a gear-type reduction mechanism, as described above, a large torque can be achieved while reducing the motor of the reaction force generator. it can.

In an indirect drive type connected indirectly via a gear type reduction mechanism, at least two reaction force generators are directly connected to the primary gear attached to the column shaft at at least two positions. Or, by indirectly meshing, at least two reaction force generators can be used properly depending on the rotation direction of the column shaft, or when one reaction force generator fails for some reason, the other reaction force generator Or you can make it complete.
JP2006-1483 JP2006-15865

  However, the above steering system has the following problems.

  That is, in the case of an indirect drive type in which the column shaft and the reaction force generation device are indirectly connected via a gear type reduction mechanism, the backlash usually exists in the gear, and the backlash causes backlash. There is a problem that a smooth feeling of operation of the steering wheel is hindered.

  As shown in FIG. 4, the backlash is a gap f formed behind the teeth d and e of the meshing portion c when the gears a and b mesh with each other.

  In order to solve the above-mentioned problem, in the invention described in claim 1, the control device is installed in a state in which the steering device and the steering device are mechanically separated, and can control the steering device and the steering device. The steering device includes at least a column shaft having a steering wheel, a reaction force generation device, and a gear-type reduction mechanism provided therebetween, and at least two reaction force generation devices are provided. The speed reduction mechanism has at least a primary gear attached to the column shaft, and at least two reaction force generators are configured to directly or indirectly mesh with the primary gear at at least two positions. In the above steering system, the control device rotates the primary gear in the opposite direction with respect to at least two reaction force generators. It is configured to generate a control signal for preventing backlash that can prevent backlash due to backlash at the two meshing parts by generating a torque and making the primary gear lightly restricted. It features an improved steering system.

  According to invention of Claim 1, the following effects can be acquired by the said structure. That is, when the control device outputs a control signal for preventing rattling to at least two reaction force generation devices, at least two reaction force generation devices rotate the primary gear in the opposite direction. Each pressurizing torque is generated, and the primary gear is brought into a light rotation restraint state. Thereby, it is possible to prevent the occurrence of backlash due to backlash at two meshing portions. Thus, it is possible to ensure a smooth operation feeling of the steering wheel.

  Hereinafter, embodiments embodying the present invention will be described together with illustrated examples.

  1 to 3 show an embodiment of the present invention.

  First, the configuration will be described.

  A vehicle such as an automobile is provided with a steering system 1. The steering system 1 is a steer-by-wire system 2.

  In this steer-by-wire system 2, the steering device 3 and the steered device 4 are provided in a mechanically separated state. The steering device 3 and the steering device 4 are configured to be controlled by the control device 5.

  The steering device 3 described above includes at least a column shaft 7 having a steering wheel 6 and reaction force generators 8 and 9.

  The steering device 3 is an indirect drive type in which the column shaft 7 and the reaction force generators 8 and 9 are indirectly connected via a gear-type reduction mechanism 11.

  And at least two reaction force generators 8 and 9 are provided. Further, the speed reduction mechanism 11 has at least a primary gear 12 attached to the column shaft 7. At least two reaction force generators 8 and 9 are configured to mesh directly or indirectly with the primary gear 12 at at least two positions.

  In this case, at least two reaction force generators 8 and 9 are drive devices such as reaction force generation motors 13 and 14. Motor pinion gears 15 and 16 are attached to the output shafts of the reaction force generating motors 13 and 14, respectively. The motor pinion gears 15 and 16 are indirectly meshed with the primary gear 12 via the secondary gears 17 and 18, respectively. The secondary gears 17 and 18 are, for example, a two-stage gear having a large-diameter gear portion that meshes with the motor pinion gears 15 and 16 and a small-diameter gear portion that meshes with the primary gear 12 in two stages on the same axis. Has been. It is assumed that the reduction ratio between the two reaction force generators 8 and 9 and the primary gear 12 is set to be the same.

  On the other hand, the steering device 4 is not specifically described in detail, but a steering rack 23 that can be moved in the axial direction 22 (substantially in the vehicle width direction) by the steering motor 21 and balls on both ends of the steering rack 23. A pair of tie rods 25 connected via a joint 24 and a pair of steered wheels 27 connected to both ends of the tie rod 25 via a ball joint (not shown) are provided.

  The control device 5 is mainly composed of a control device 31. The control device 31 includes a torque detection signal 33 from a torque sensor 32 attached to the column shaft 7 and the like, an angle detection signal 35 from an angle sensor 34, vehicle body information 36 (signal from a vehicle speed, a yaw rate sensor not shown), A turning angle detection signal 38 or the like from a turning angle sensor 37 attached to the steering rack 23 or the like is input and controlled to the reaction force generation devices 8 and 9 (reaction force generation motors 13 and 14) of the steering device 3. Signals 41 and 42 are sent to generate a steering reaction force 45 (see FIG. 3; the same applies to the following), and a control signal 43 is sent to the turning motor 21 of the turning device 4 to make it turn. It is configured.

  The above configuration is almost the same as that of the conventional example described above.

  And with respect to such a basic configuration, in this embodiment, the control device 5 causes the minute pressurization to rotate the primary gear 12 in the opposite direction with respect to at least two reaction force generation devices 8 and 9. A control signal for preventing backlash that can prevent backlash due to backlash at the two meshing portions 53 and 54 by generating torques 51 and 52 respectively and causing the primary gear 12 to be in a light rotation restraint state. 57 and 58 can be output.

  The control signals 57 and 58 for preventing rattling are superimposed on the control signals 41 and 42, for example. Basically, it is preferable that at least one or both of the control signals 57 and 58 for preventing rattling be output at all times during the control of the control device 5 (control device 31). Further, the minute pressurizing torques 51 and 52 generated by the control signals 57 and 58 for preventing backlash are equal to each other.

  Note that the minute pressurizing torques 51 and 52 are minimum torques necessary to prevent the occurrence of backlash due to backlash.

  Further, the light rotation constraint state is a minimum rotation constraint state that does not affect the steering reaction force 45.

  Further, the pressurizing torques 51 and 52 can be optimally set according to the radix of the reaction force generators 8 and 9, the reduction ratio of the speed reduction mechanism 11, the gear shape of the speed reduction mechanism 11, and the like.

  Next, the operation of this embodiment will be described.

  When the steering device 3 is operated, the control device 5 detects this and sends a control signal 43 to the steering device 4 to cause the steering device 4 to steer.

  At this time, the control device 5 detects the operation of the steering device 3 by inputting the torque detection signal 33 from the torque sensor 32 attached to the column shaft 7 and the like, the angle detection signal 35 from the angle sensor 34, and the like.

  Then, the control device 5 sends a control signal 43 to the steering motor 21 to move the steering rack 23 in the axial direction 22, thereby turning the steered wheels 27 via the ball joint 24 and the tie rod 25.

  At the same time, when the steering device 4 is steered, the control device 5 detects this and sends control signals 41 and 42 to the reaction force generators 8 and 9 of the steering device 3, and the column shaft 7 and the steering device 3. A steering reaction force 45 is generated on the steering wheel 6.

  At this time, the control device 5 detects turning of the turning device 4 by inputting a turning angle detection signal 38 or the like from a turning angle sensor 37 attached to the steering rack 23 or the like. In addition, the control device 5 inputs the vehicle body information 36 (a signal from a vehicle speed, a yaw rate sensor not shown) or the like to determine the state of the vehicle body at this time.

  Then, the control device 5 sends control signals 41 and 42 to the reaction force generators 8 and 9 (reaction force generation motors 13 and 14) of the steering device 3, and the motor pinion gears 15 and 16, the secondary gears 17 and 18, the primary A steering reaction force 45 is generated on the column shaft 7 and the steering wheel 6 of the steering device 3 via the gear 12.

  At this time, the reaction force generating motors 13 and 14 of the reaction force generators 8 and 9 are indirectly connected to the column shaft 7 via the gear type reduction mechanism 11. A large torque can be achieved while reducing the torque.

  In the indirect drive type that is indirectly connected via the gear type reduction mechanism 11, at least two reaction force generators 8 and 9 are at least connected to the primary gear 12 attached to the column shaft 7. By directly or indirectly meshing at two positions, at least two reaction force generators 8 and 9 are selectively used depending on the rotation direction of the column shaft 7, or one reaction force generator 8 or When 9 is lost, the other reaction force generators 8 and 9 can be used for complementation.

  According to this embodiment, the steering device 3 and the steering device 4 are installed in a mechanically separated state, and the control device 5 capable of controlling the steering device 3 and the steering device 4 is provided. The steering device 3 includes at least a column shaft 7 having a steering wheel 6, reaction force generation devices 8 and 9, and a gear-type reduction mechanism 11 provided therebetween, and the reaction force generation devices 8 and 9. At least two, the speed reduction mechanism 11 has at least a primary gear 12 attached to the column shaft 7, and at least two reaction force generators 8 and 9 are provided at least at two locations with respect to the primary gear 12. In the steering system configured to mesh directly or indirectly in position, the control device 5 controls the primary gear 12 with respect to at least two reaction force generation devices 8 and 9. By generating minute pressurizing torques 51 and 52 that are rotated in the direction of rotation to place the primary gear 12 in a light rotation restraint state, the backlash at the two meshing portions 53 and 54 is caused by backlash. By being configured to output the control signals 57 and 58 for preventing backlash that can be prevented, the following operational effects can be obtained.

  That is, when the control device 5 outputs the control signals 57 and 58 for preventing rattling to at least two reaction force generators 8 and 9, at least two reaction force generators 8 and 9 are primary. Small pressurizing torques 51 and 52 for rotating the gear 12 in the opposite direction are generated, respectively, so that the primary gear 12 is in a light rotation restraint state. As a result, it is possible to prevent the backlash from occurring at the two meshing portions 53 and 54 due to backlash. Thus, it is possible to ensure a smooth operation feeling of the steering wheel 6.

  More specifically, when the steering reaction force 45 is not generated, such as when the vehicle is traveling straight without rotating the steering wheel 6, two reaction force generators 8 and 9 are generated as shown in FIG. Since the minute pressurizing torques 51 and 52 are equal, the minute pressurizing torques 51 and 52 cancel each other, and the primary gear 12 does not rotate. However, since the primary gear 12 and the secondary gears 17 and 18 are in contact with each other at the two meshing portions 53 and 54, the backlash does not matter which direction the primary gear 12 rotates. There will be no backlash caused by.

  Then, when the steering reaction force 45 (in this case, the primary gear 12 is counterclockwise) is generated by rotating the steering wheel 6 from the state of FIG. 2, the state shown in FIG. As described above, the steering reaction force 45 (in this case, the minute pressurizing torque 51 is superimposed) is sufficiently larger than the minute pressurizing torque 52, so that the primary gear 12 is rotated without any problem. The steering reaction force 45 is transmitted to the driver. At this time, since the primary gear 12 and the secondary gear 18 are in contact with each other at the meshing portion 54 by the minute pressurizing torque 52, when the secondary gear 18 is rotated, there is a backlash caused by backlash. There is no feeling of sticking. Even when the primary gear 12 is turned clockwise or when the primary gear 12 is continuously reversed, the backlash does not cause backlash in substantially the same manner as described above. Therefore, it is possible to obtain a good operational feeling without play.

  Although the embodiments of the present invention have been described in detail with reference to the drawings, the embodiments are only examples of the present invention, and the present invention is not limited to the configurations of the embodiments. Needless to say, design changes and the like within a range not departing from the gist of the invention are included in the present invention. Further, for example, when each embodiment includes a plurality of configurations, it is a matter of course that possible combinations of these configurations are included even if not specifically described. Further, when a plurality of embodiments and modifications are shown, it is needless to say that possible combinations of configurations extending over these are included even if not specifically described. Further, the configuration depicted in the drawings is of course included even if not particularly described.

It is a block diagram of the steering system concerning the Example of this invention. It is explanatory drawing to which the deceleration mechanism part of FIG. 1 was expanded when the steering reaction force is not acting. It is explanatory drawing which expanded the deceleration mechanism part of FIG. 1 in case the steering reaction force is acting. It is explanatory drawing of a backlash.

Explanation of symbols

3 Steering device 4 Steering device 5 Control device 6 Steering wheel 7 Column shaft 7
DESCRIPTION OF SYMBOLS 8 Reaction force generator 9 Reaction force generator 11 Deceleration mechanism 12 Primary gear 51 Pressurizing torque 52 Pressurizing torque 53 Engagement part 54 Engagement part 57 Control signal for rattling prevention 58 Control signal for rattling prevention

Claims (1)

The steering device and the steering device are installed in a state where they are mechanically separated, and a control device capable of controlling the steering device and the steering device is provided,
The steering device includes at least a column shaft having a steering wheel, a reaction force generator, and a gear-type reduction mechanism provided between the two,
At least two reaction force generators are provided,
The speed reduction mechanism has at least a primary gear attached to the column shaft;
In a steering system in which at least two reaction force generating devices are configured to directly or indirectly mesh with a primary gear at at least two positions,
The control device generates a small pressurizing torque for rotating the primary gear in the opposite direction with respect to at least two reaction force generators, and puts the primary gear into a light rotation restraint state. A steering system configured to output a control signal for preventing rattling that can prevent rattling due to backlash at the meshing portion of the portion.

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