JP2013095310A - Steer-by-wire steering apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a steer-by-wire steering apparatus which can be small-sized and whose length in the axial direction can be reduced.SOLUTION: A steer-by-wire steering apparatus comprises: a steering input device; a steering device 2 separated mechanically therefrom; and a steering control device which controls the steering device 2 in accordance with an input signal from the steering input device. The steering device 2 includes a steering actuator 6, and a linear mechanism section 8 which converts revolution of a revolving output shaft 7 into linear motion and transmits it to a steering link mechanism. The linear mechanism section 8 includes: an outer wheel member 13 at an outer radial side of the revolving output shaft 7; a carrier 14 supported by the revolving output shaft 7; a plurality of planetary rollers 16 which are supported by a support pin 15 and disposed between the revolving output shaft 7 and the outer wheel member 13; an axial-direction relative moving means 17 which converts the rotation/revolution of the planetary rollers 16 into relative movement in the axial direction with respect to the outer ring member 13 or the revolving output shaft 7; and an arm 18 which steers steering wheels by transmitting the movement in the axial direction of the outer wheel member 13 corresponding to the relative movement of the planetary rollers 16 to the steering link mechanism.

Description

  The present invention relates to a steer-by-wire steering device for a vehicle in an electric vehicle or the like.

As this type of steer-by-wire steering device, a steering input device such as a steering wheel, a steering link mechanism mechanically separated from the steering input device, and the steering link mechanism are driven in accordance with the operation of the steering input device. An actuator including a turning actuator and a ball screw mechanism has been proposed (for example, Patent Document 1).
In this steer-by-wire steering device, the ball screw mechanism includes a screw shaft and a nut shaft, the steering link mechanism is rotatably supported on the nut shaft, and the screw shaft is rotationally driven by a steering actuator. Thus, the steering link mechanism is driven via the nut shaft.

JP 2007-326459 A

  In an electric vehicle, it is necessary to install a battery, an inverter, or the like in a portion corresponding to an engine room of a gasoline vehicle to secure a wide space in the vehicle. Therefore, the steered mechanism of the steer-by-wire type steering apparatus needs to be structured to fit in the wheel house. However, in the steer-by-wire type steering apparatus disclosed in Patent Document 1 having a ball screw mechanism, it is necessary to interpose a speed reducer between the steering actuator and the ball screw (linear motion mechanism) in order to generate torque required for steering. There is. For this reason, it is necessary to ensure space in the axial direction. Further, since the motor is rotated at the time of reverse input from the tire, it is necessary to always control the motor (consumption of power) or to add a reverse input prevention mechanism.

  An object of the present invention is to provide a steer-by-wire type steering device that can be downsized and shortened in the axial direction.

A steer-by-wire steering device according to the present invention includes a steering input device, a steering device mechanically separated from the steering input device, and a steering device that controls the steering device based on an input signal from the steering input device. In a steer-by-wire steering device comprising a control device,
The steering device includes a turning actuator that has a rotation output shaft and serves as a driving source for turning, and the rotation of the rotation output shaft of the steering actuator is converted into a linear movement in the axial direction and coupled to the steered wheels. And a linear motion mechanism that transmits to the steering link mechanism.
The linear motion mechanism section includes an outer ring member disposed concentrically on the outer diameter side of the rotation output shaft, a carrier rotatably supported by the rotation output shaft, and a support pin provided on the carrier. A plurality of planets that are rotatably supported and are arranged between an outer diameter surface of the rotation output shaft and an inner diameter surface of the outer ring member and revolve around the rotation output shaft as the rotation output shaft rotates. A roller, between each of these planetary rollers and the outer ring member, or between each of the planetary rollers and the rotation output shaft, and converts the planetary roller's self-revolution into an axial movement to convert the outer ring member or Axial relative movement means for moving each planetary roller in the axial direction relative to the rotation output shaft, and axial movement of the outer ring member according to the relative movement of each planetary roller are transmitted to the steering link mechanism. Steered wheels And having an arm that.

According to this configuration, in the turning device, the rotation of the rotation output shaft of the turning actuator is converted into the axial movement of the outer ring member by the self-revolution of the planetary roller. In addition to functioning as a conversion mechanism that converts to linear motion, it also serves as a speed reducer, enabling downsizing and shortening of the axial length. As a result, the steered mechanism of the steer-by-wire steering device can be housed in the wheel house, and a vehicle interior space can be secured accordingly.
Moreover, since the load can be held by using the planetary roller as the conversion mechanism that converts the rotational force into the linear motion, the turning angle can be held when the vehicle goes straight. Therefore, it is possible to prevent reverse input from the steered wheels that are traveling, and it is also possible to save power.

In the present invention, the axial relative movement means includes a spiral ridge provided on the inner diameter surface of the outer ring member or the outer diameter surface of the rotation output shaft, and each planetary roller at an equal pitch with the ridge. It is good also as what consists of a circumferential groove | channel provided in an outer-diameter surface and fitting in the said protruding item | line.
In this case, the circumferential groove provided on the outer diameter surface of each planetary roller may have a lead angle different from that of the spiral protrusion.

  In this invention, the said axial direction relative movement means is provided in the outer-diameter surface of the said rotation output shaft by the same pitch as the circumferential direction arrangement | sequence of each said planetary roller, The helical groove | channel which the outer-diameter surface of each said planetary roller fits It may be composed of

  In the present invention, the linear motion mechanism portion is provided with a rotation stopper that prevents the outer ring member from rotating.

  In the present invention, the linear motion mechanism section includes one or more thrust bearings that support the rotation of the planetary rollers, and one or more thrust bearings that support the revolution of the planetary rollers. Also good.

  In the present invention, the linear motion mechanism portion may be covered with a housing, and the linear motion mechanism portion may be lubricated with a lubricant sealed in the housing.

  In this case, the housing may be provided with one or a plurality of fixing portions for fixing the steering device to the vehicle body. In this case, the fixing portion may be provided on the arrangement side of the linear motion mechanism portion in the housing.

  In this invention, the arm may be connected to the steering link mechanism.

  In the present invention, the main body portion of the steering actuator is disposed so that its axis is parallel to the rotation output shaft disposed in the linear motion mechanism portion, and the rotational output from the main body portion of the steering actuator is used as the power. You may make it transmit to the said rotation output shaft via a transmission mechanism. The main body is, for example, a motor. In the case of this configuration, the axial length of the apparatus can be further shortened.

  In this case, the power transmission mechanism may be a gear, a belt, or a chain. When a gear mechanism is used as the power transmission mechanism, a larger torque can be obtained. In addition to the gear, a belt or a chain may be used for the configuration of the power transmission mechanism. Further, when the power transmission mechanism is composed of a gear, the gear may be a spur gear, a helical gear, or a bevel gear.

  In the present invention, the main body of the steering actuator may be a motor. In this case, the motor may be a motor with an angle sensor.

  In this invention, in the linear motion mechanism portion, a spiral protrusion or spiral groove forming portion on the outer surface of the rotation output shaft, a spiral protrusion on the outer diameter surface of each planetary roller and the inner surface of the outer ring member, However, it is desirable from the viewpoint of wear resistance that it is made of a surface-modified member. Examples of the surface-modified member include a member in which a sliding material such as PTEE is dispersed in electroless Ni, a DLC film, and the like.

A vehicle according to the present invention includes the steer-by-wire steering device according to any one of the above-described inventions.
According to this configuration, the steer-by-wire steering device can be reduced in size and the axial length can be shortened, so the steering mechanism of the steer-by-wire steering device can be accommodated in the wheelhouse, and the interior space is secured accordingly. can do.

A steer-by-wire steering device according to the present invention includes a steering input device, a steering device mechanically separated from the steering input device, and a steering device that controls the steering device based on an input signal from the steering input device. In a steer-by-wire steering apparatus including a control device, the steering device includes a turning actuator having a rotation output shaft and serving as a driving source for turning, and rotation of the rotation output shaft of the steering actuator in an axial direction. A linear motion mechanism that converts the linear motion to a steering link mechanism that is coupled to the steered wheels, and the linear motion mechanism is disposed concentrically on the outer diameter side of the rotary output shaft. An outer ring member, a carrier rotatably supported by the rotation output shaft, and an outer diameter surface of the rotation output shaft and an inner diameter surface of the outer ring member that are rotatably supported by a support pin provided on the carrier. Placed between A plurality of planetary rollers that revolve while rotating around the rotation output shaft as the rotation output shaft rotates, and between each of these planetary rollers and the outer ring member, or between each planetary roller and the rotation output shaft. Axial relative movement means provided between the planetary rollers to convert the planetary revolutions into axial movements to move the planetary rollers relative to the outer ring member or the rotation output shaft in the axial direction; Since it has an arm that transmits the axial movement of the outer ring member according to the relative movement of the roller to the steering link mechanism to steer the steered wheel, the apparatus can be downsized and the axial length is short. it can.
Since the vehicle according to the present invention includes the steer-by-wire type steering device according to the above-described invention, the steer-by-wire type steering device can be reduced in size and the axial length can be shortened. The vehicle interior space can be secured accordingly.

1 is a block diagram showing a schematic configuration of a steer-by-wire steering device according to an embodiment of the present invention. It is a top view of the steering apparatus in the steer-by-wire type steering apparatus. It is a top view which fractures | ruptures and shows the linear motion mechanism part of the same steering apparatus. It is a top view which fractures | ruptures and shows the linear motion mechanism part of the steering apparatus in the steer-by-wire type steering apparatus concerning other embodiment of this invention. It is a top view which fractures | ruptures and shows the linear motion mechanism part of the steering apparatus in the steer-by-wire type steering apparatus concerning further another embodiment of this invention. It is VI-VI arrow sectional drawing of FIG.

  An embodiment of the present invention will be described with reference to FIGS. This steer-by-wire type steering device is applied to steering of steered wheels 10 (here, left and right front wheels) of an electric vehicle, for example, as schematically shown in FIG. A steering device 2 mechanically separated from the input device 1 and a steering control device 3 for controlling the steering device 2 based on an input signal from the steering input device 1 are provided. The steering input device 1 includes, for example, a steering wheel that is steered by a driver, and inputs a steering angle, which is steering information, to the steering control device 3 as an input signal. The steered control device 3 is incorporated as part of an ECU (electric control unit) 4 that controls the entire vehicle. The steered device 2 is separately disposed in the vehicle body 9 corresponding to each steered wheel 10, and a steering link mechanism 5 is interposed between each steered device 2 and the steered wheel 10 corresponding thereto. The steering link mechanism 5 includes a knuckle arm 11 and a tie rod 12.

  As shown in FIG. 3, the turning device 2 includes a turning actuator 6 that has a rotation output shaft 7 and serves as a driving source for turning, and a linear motion mechanism unit 8. Here, an electric motor is used as the steering actuator 6, and the steering actuator 6 is arranged side by side on the same axis as the linear motion mechanism unit 8. A rotor shaft of a motor is used as the rotation output shaft 7 of the steering actuator 6. For example, a motor with an angle sensor is used as the motor serving as the steering actuator 6. The linear motion mechanism unit 8 has a function of converting the rotation of the rotation output shaft 7 of the steering actuator 6 into a linear movement in the axial direction and transmitting it to the steering link mechanism 5 connected to the steered wheels 10.

  The linear motion mechanism 8 includes an outer ring member 13 disposed concentrically on the outer diameter side of the rotation output shaft 7, a carrier 14 rotatably supported on the outer periphery of the rotation output shaft 7, and the carrier 14. A plurality of planetary rollers 16 rotatably supported by the provided support pins 15; an axial relative movement means 17 for relatively moving each planetary roller 16 in the axial direction with respect to the outer ring member 13 or the rotation output shaft 7; And an arm 18 that transmits the axial movement of the outer ring member 13 according to the relative movement of each planetary roller 16 to the steering link mechanism 5 to steer the steered wheel 10. The arm 18 is connected to the steering link mechanism 5. The linear motion mechanism 8 is covered with a housing 19 integrated with an exterior body of the steering actuator 6 composed of the motor, and the linear motion mechanism 8 is lubricated by the lubricant enclosed in the housing 19. The

  Three or more planetary rollers 16 are arranged at an equal pitch in the circumferential direction between the outer diameter surface of the rotation output shaft 7 and the inner diameter surface of the outer ring member 13, and as the rotation output shaft 7 rotates. Revolves while rotating around the rotation output shaft 7. A pair of the carriers 14 are arranged in the axial direction across the planetary rollers 16, and a plurality of support pins 15 are provided across the carriers 14. A rolling bearing 20 is provided between the inner diameter surfaces of both carriers 14 and the outer diameter surface of the rotary output shaft 7. A plurality of thrust bearings 21 that support the rotation of the planetary rollers 16 are provided between the carriers 14 and the end surfaces of the planetary rollers 16 facing one of the side surfaces. Furthermore, spacers 22 and 23 rotatably supported by the rotation output shaft 7 are respectively provided on the side surfaces of the carriers 14 opposite to the side surfaces facing the planetary rollers 16. A planetary roller 16 is provided between one spacer 22 close to the main part of the steered actuator 6 and a part 19a of the housing 19 projecting from the main part of the steered actuator 6 to the linear motion mechanism 8 side. A thrust bearing 24 is provided to support the revolution. Further, a thrust bearing that supports the revolution of the planetary roller 16 also between the other spacer 23 that is axially spaced from the main portion of the steering actuator 6 and the shoulder portion 13 a that projects to the inner diameter side of the outer ring member 13. 24 is provided. A base end portion of the rotation output shaft 7 is supported by a part 19 a of the housing 19 via a rolling bearing 27. In addition, between the said spacer 24 and the shoulder part 13a of the outer ring member 13, the rotation stopper (not shown) which stops the outer ring member 13 is provided.

  Axial relative movement means 17 for relatively moving each planetary roller 16 in the axial direction is provided between each planetary roller 16 and the outer ring member 13 or between each planetary roller 16 and the rotation output shaft 7. Here, the spiral ridge 25 provided on the inner diameter surface of the outer ring member 13, and the circumference provided on the outer diameter surface of each planetary roller 16 at the same pitch as the ridge 25 and fitted into the ridge 25. The directional groove 26 constitutes the axial relative movement means 17. In this case, the circumferential groove 26 provided on the outer diameter surface of each planetary roller 16 may have a lead angle different from that of the spiral ridge 25. When the axial relative movement means 17 is configured in this way, the outer ring member 13 moves in the axial direction by the movement of the planetary roller 16 that revolves around the rotation output shaft 7 as the rotation output shaft 7 rotates.

  In addition, a spiral ridge 25 is provided on the outer diameter surface of the rotation output shaft 7, and the axial relative movement means 17 is connected to the circumferential groove 26 on the outer diameter surface of each planetary roller 16 fitted into the ridge 25. May be configured. When the axial relative movement means 17 is configured in this way, the planetary roller 16 moves in the axial direction while revolving around the rotation output shaft 7 along with the rotation of the rotation output shaft 7, and together with the planetary roller 16, the outer ring The member 13 also moves in the axial direction.

  Further, as the axial direction relative movement means 17, a spiral groove in which the outer diameter surface of each planetary roller 16 is fitted is formed on the outer diameter surface of the rotation output shaft 7 at the same pitch as the circumferential arrangement of the planetary rollers 16. May be. Even when the axial relative movement means 17 is configured as described above, the planetary roller 16 moves in the axial direction while revolving around the rotation output shaft 7 along with the rotation of the rotation output shaft 7. At the same time, the outer ring member 13 also moves in the axial direction.

  In these cases, the spiral ridges 25 or spiral grooves on the outer diameter surface of the rotary output shaft 7, the outer diameter surfaces of the planetary rollers 16, and the spiral ridges 25 on the inner diameter surface of the outer ring member 13 are formed. It is desirable from the viewpoint of wear resistance that the formation site is made of a surface-modified member. Examples of the surface-modified member include a member in which a sliding material such as PTEE is dispersed in electroless Ni, a DLC film, and the like.

  As shown in FIG. 2, which shows an external view of the steering device 2, the housing 19 is provided with one or a plurality of fixing portions 28 for fixing the steering device 2 to the vehicle body 9 (FIG. 1). Here, the fixing portion 28 is provided on the arrangement side of the linear motion mechanism portion 8. A portion extending from the arm 18 protruding in the axial direction from the linear motion mechanism 8 to the knuckle arm 11 of the steering link mechanism 5 is covered with a bellows-like boot 29.

  According to the steer-by-wire steering apparatus having this configuration, the steering information associated with the operation is input as an input signal from the steering input device 1 such as a steering wheel to the steering control device 3 of the ECU 4, and the steering control device 3 receives the input signal. Based on this, each steered device 2 corresponding to both steered wheels 10 is controlled. In the turning device 2, the turning actuator 6 rotates the rotation output shaft 7 by an amount corresponding to the turning information. As the rotation output shaft 7 rotates, each planetary roller 16 revolves while rotating around the rotation output shaft 7 in the linear motion mechanism portion 8 of the steering device 2. Along with this, the axial relative movement means 17 converts the self-revolution of each planetary roller 16 into relative movement in the axial direction with respect to the outer ring member 13 or the rotation output shaft 7. As a result, the outer ring member 13 moves in the axial direction according to the relative movement amount of each planetary roller 16, and this axial movement is transmitted to the steering link mechanism 5 via the arm 18, and the steered wheel 10 is steered.

Thus, in this steer-by-wire type steering device, the turning device 2 converts the rotation of the rotation output shaft 7 of the steering actuator 6 into the axial movement of the outer ring member 13 by the self-revolution of the planetary roller 16. As a result, the planetary roller 16 mechanism not only functions as a conversion mechanism that converts rotational force into linear motion, but also serves as a speed reducer, enabling downsizing and shortening of the axial length. Become. That is, in the conventional linear motion mechanism using the ball screw, it is necessary to provide a speed reducer between the motor and the ball screw in order to generate torque required for turning, but the linear motion mechanism using the self-revolution of the planetary roller 16 By setting it as the part 8, it can serve as a conversion function to linear motion and a deceleration function, and it is possible to reduce the size and the axial length. As a result, the steered mechanism of the steer-by-wire steering device can be housed in the wheel house, and a vehicle interior space can be secured accordingly.
Further, since the load can be maintained by using the planetary roller 16 with a screw as a conversion mechanism for converting the rotational force into a linear motion, it is possible to maintain the turning angle by straight traveling of the vehicle, It is possible to prevent reverse input from the steering wheel, and from these, power saving can also be achieved.

  FIG. 4 shows another embodiment of the present invention. In this steer-by-wire type steering apparatus, the motor 30 that is the main body of the steering actuator 6 in the steering apparatus 2 is arranged so that its axis is parallel to the rotation output shaft 7 arranged in the linear motion mechanism section 8. It is arranged. That is, in this case, the rotation output shaft 7 is a separate member from the rotor shaft of the motor 30. The rotation output from the motor 30 is transmitted to the rotation output shaft 7 via the power transmission mechanism 31. Here, an input rotation member 32 such as a gear provided on the rotation output shaft 7 is shown as a part of the power transmission mechanism 31. Although not shown, the rotor shaft of the motor 30 is provided with an output rotating member such as a gear, and the output rotating member and the input rotating member 32 mesh with each other via an intermediate gear (not shown). A power transmission mechanism 31 is configured. In this case, a spur gear, a helical gear, a bevel gear, or the like can be used as the input rotation member 32 or the output rotation member constituting the power transmission mechanism 31. Other configurations are the same as those of the previous embodiment shown in FIGS.

Thus, in this embodiment, in the steering device 2, the motor 30 that is the main part of the steering actuator 6 is parallel to the rotation output shaft 7 whose axis is disposed in the linear motion mechanism 8. Thus, the axial length of the apparatus can be further shortened. Further, when a gear mechanism is used as the power transmission mechanism 31 for transmitting the rotation from the motor 30 to the rotation output shaft 7, a larger torque can be obtained.
Note that the power transmission mechanism 31 may be a winding type mechanism using a sprocket or pulley and an endless chain or belt.

  5 and 6 show still another embodiment of the present invention. 6 shows a cross-sectional view taken along the line VI-VI in FIG. In this steer-by-wire type steering apparatus, in the embodiment shown in FIGS. 1 to 3, a plurality of notches 18 a are provided on the end surface of the arm 18 on the outer ring member 13 side, and the engagement is provided on the arm side end surface of the outer ring member 13. Anti-rotation means 33 for engaging the protrusion 13b with the notch 18a of the arm 18 to prevent the outer ring member 13 from rotating is configured. Other configurations are the same as those of the embodiment shown in FIGS.

DESCRIPTION OF SYMBOLS 1 ... Steering input device 2 ... Steering device 3 ... Steering control device 5 ... Steering link mechanism 6 ... Steering actuator 7 ... Rotation output shaft 8 ... Linear motion mechanism part 10 ... Steering wheel 13 ... Outer wheel member 14 ... Carrier 15 ... Support pin 16 ... Planetary roller 17 ... Axial relative movement means 18 ... Arm 19 ... Housing 21 ... Thrust bearing 24 ... Thrust bearing 25 ... Spiral ridge 26 ... Circumferential groove 28 ... Fixed portion 30 ... Motor 31 ... Power transmission Mechanism 32 ... Input gear 33 ... Non-rotating

Claims (10)

Steer-by-wire steering apparatus comprising a steering input device, a steering device mechanically separated from the steering input device, and a steering control device that controls the steering device based on an input signal from the steering input device In
The steering device includes a turning actuator that has a rotation output shaft and serves as a driving source for turning, and the rotation of the rotation output shaft of the steering actuator is converted into a linear movement in the axial direction and coupled to the steered wheels. And a linear motion mechanism that transmits to the steering link mechanism.
The linear motion mechanism section includes an outer ring member disposed concentrically on the outer diameter side of the rotation output shaft, a carrier rotatably supported by the rotation output shaft, and a support pin provided on the carrier. A plurality of planets that are rotatably supported and are arranged between an outer diameter surface of the rotation output shaft and an inner diameter surface of the outer ring member and revolve around the rotation output shaft as the rotation output shaft rotates. A roller, between each of these planetary rollers and the outer ring member, or between each of the planetary rollers and the rotation output shaft, and converts the planetary roller's self-revolution into an axial movement to convert the outer ring member or Axial relative movement means for moving each planetary roller in the axial direction relative to the rotation output shaft, and axial movement of the outer ring member according to the relative movement of each planetary roller are transmitted to the steering link mechanism. Steered wheels Steer-by-wire steering apparatus characterized by having an arm that.   2. The axial relative movement means according to claim 1, wherein the planetary roller has a spiral ridge provided on an inner diameter surface of the outer ring member or an outer diameter surface of the rotation output shaft, and an equal pitch with the ridge. A steer-by-wire type steering device comprising a circumferential groove that is provided on the outer diameter surface of the rim and is fitted into the ridge.   3. The steer-by-wire steering apparatus according to claim 2, wherein the circumferential groove provided on the outer diameter surface of each planetary roller has a lead angle different from that of the spiral protrusion.   2. The spiral according to claim 1, wherein the axial relative movement means is provided on the outer diameter surface of the rotation output shaft at the same pitch as the circumferential arrangement of the planet rollers, and the outer diameter surfaces of the planet rollers are fitted to each other. A steer-by-wire steering device consisting of grooves.   5. The steer-by-wire steering device according to claim 1, wherein the linear motion mechanism portion is provided with a detent that prevents rotation of the outer ring member. 6.   6. The linear motion mechanism according to claim 1, wherein the linear motion mechanism section includes one or more thrust bearings that support the rotation of the planetary rollers, and one that supports the revolution of the planetary rollers. Alternatively, a steer-by-wire steering device having a plurality of thrust bearings.   7. The steer-by-wire type steering apparatus according to claim 1, wherein the linear motion mechanism is covered with a housing, and the linear motion mechanism is lubricated with a lubricant enclosed in the housing.   The steering unit according to any one of claims 1 to 7, wherein a main body portion of the steering actuator is disposed so that an axis thereof is parallel to the rotation output shaft disposed in the linear motion mechanism portion. A steer-by-wire steering apparatus that transmits a rotational output from a main body of an actuator to the rotational output shaft through a power transmission mechanism.   The steer-by-wire steering device according to any one of claims 1 to 8, wherein a main body portion of the steering actuator is a motor and has an angle sensor.   A vehicle comprising the steer-by-wire steering device according to any one of claims 1 to 9.

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