阅读说明：本技术 用于转动可转向的车轮的装置 (Device for rotating steerable vehicle wheels ) 是由 K·博伊尔 R·尼伦贝格 B·朔恩 于 2020-03-05 设计创作，主要内容包括：本发明涉及一种用于转动可转向的车轮的装置,该装置包括具有与车辆方向盘连接的小齿轮的转向柱,从而使得方向盘的旋转引起小齿轮的旋转。电动的转向单元包括具有可绕轴线旋转的第一输出轴的电动机。第一行星齿轮级具有第一齿轮减速比并且由第一输出轴驱动。第二行星齿轮级由第一行星齿轮级和小齿轮驱动并且具有与第一齿轮减速比不同的第二齿轮减速比。第二输出轴由第二行星齿轮级驱动并联接到可转向的车轮,从而使得第二输出轴的旋转影响车轮的转向。(The present invention relates to an apparatus for turning a steerable wheel, the apparatus comprising a steering column having a pinion gear coupled to a vehicle steering wheel such that rotation of the steering wheel causes rotation of the pinion gear. The electric power steering unit includes an electric motor having a first output shaft rotatable about an axis. The first planetary gear stage has a first gear reduction ratio and is driven by a first output shaft. The second planetary gear stage is driven by the first planetary gear stage and the pinion gear and has a second gear reduction ratio that is different from the first gear reduction ratio. The second output shaft is driven by the second planetary gear stage and is coupled to the steerable wheel such that rotation of the second output shaft affects steering of the wheel.)

1. An apparatus for turning a steerable wheel, the apparatus comprising:

a steering column having a pinion coupled to a steering wheel of a vehicle such that rotation of the steering wheel causes rotation of the pinion;

an electric power steering unit comprising:

an electric motor having a first output shaft rotatable about an axis;

a first planetary gear stage having a first gear reduction ratio and driven by the first output shaft;

a second planetary gear stage driven by the first planetary gear stage and the pinion gear and having a second gear reduction ratio different from the first gear reduction ratio; and

a second output shaft driven by the second planetary gear stage and coupled to the steerable wheel such that rotation of the second output shaft affects steering of the wheel.

2. The apparatus of claim 1, wherein the second gear reduction ratio is less than the first gear reduction ratio.

3. The device of claim 1, wherein the first gear reduction ratio is about 75:1 to about 500: 1.

4. The device of claim 1, wherein the second gear reduction ratio is about 15:1 to about 22: 1.

5. The apparatus of claim 1, wherein the first planetary gear stage and the second planetary gear stage are disposed in a housing, and wherein a bearing is coupled to the housing and houses the second output shaft.

6. The apparatus of claim 1, wherein the first and second planetary gear stages are disposed in a housing including teeth for rotatably supporting the first and second planetary gear stages.

7. The apparatus of claim 1, wherein said first output shaft of said motor directly drives said first planetary gear stage.

8. The apparatus of claim 1, further comprising:

a second motor having an output shaft;

an input shaft coupled to the first planetary gear stage; and

a drive belt connected to the input shaft and the output shaft of the motor, the drive belt for transmitting torque from the motor to the input shaft.

9. The apparatus of claim 1, wherein each of the first planetary gear stage and the second planetary gear stage comprises:

a sun gear rotatable about the axis;

a planetary gear that meshes with the sun gear and runs around the sun gear while rotating in response to rotation of the sun gear; and

a carrier connected to the planetary gear and rotatable about the axis.

10. The apparatus of claim 9, further comprising a gear engaged with the pinion gear and rotatable with the carrier of the first planetary gear stage to transfer torque from the steering wheel to the carrier of the first planetary gear stage.

11. The device of claim 1, further comprising a steering link including a first member rotatably connected to the second output shaft, a second member connected to the first member, and a third member connected to the second member and rotatably connected to the wheel such that rotation of the first member affects steering of the wheel.

12. The apparatus of claim 1, further comprising at least one sensor generating a signal indicative of a vehicle condition, and a controller coupled to the at least one vehicle condition sensor and the motor, the controller operable to control rotation of the first output shaft based on the signal from the at least one vehicle condition sensor.

13. The apparatus of claim 12, wherein the vehicle condition sensor comprises at least one of a torque sensor for detecting torque applied to the steering wheel and a position sensor for detecting a position of the steering wheel.

14. An apparatus for turning a steerable wheel, the wheel operatively connected to a steering wheel by a pinion gear, the pinion gear rotatable by the steering wheel, the apparatus comprising:

an electric power steering unit comprising:

an electric motor having a first output shaft rotatable about an axis;

a gearbox, the gearbox comprising:

a first planetary gear stage having a first gear reduction ratio and driven by the first output shaft;

a second planetary gear stage driven by the first planetary gear stage and the pinion gear, the second planetary gear stage having a second gear reduction ratio different than the first gear reduction ratio;

a second output shaft driven by the second planetary gear stage and coupled to the steerable wheel such that rotation of the second output shaft affects steering of the wheel; and

a controller for controlling rotation of the first output shaft in response to rotation of the steering wheel.

15. The apparatus of claim 14, wherein the second gear reduction ratio is less than the first gear reduction ratio.

16. The apparatus of claim 14, wherein the first gear reduction ratio is about 75:1 to about 500: 1.

17. The apparatus of claim 14, wherein the second gear reduction ratio is about 15:1 to about 22: 1.

18. The apparatus of claim 14, wherein the first planetary gear stage and the second planetary gear stage are disposed in a housing, and wherein a bearing is coupled to the housing and houses the second output shaft.

19. The apparatus of claim 14, wherein the first planetary gear stage and the second planetary gear stage are disposed in a housing including a gear arrangement to rotatably support the first planetary gear stage and the second planetary gear stage.

20. The apparatus of claim 14, wherein said first output shaft of said motor directly drives said first planetary gear stage.

21. The apparatus of claim 14, further comprising:

a second motor having an output shaft;

an input shaft connected to the first planetary gear stage; and

a drive belt connected to the input shaft and the output shaft of the motor, the drive belt for transmitting torque from the motor to the input shaft.

22. The apparatus of claim 14, wherein each of the first planetary gear stage and the second planetary gear stage comprises:

a sun gear rotatable about the axis;

a planetary gear that meshes with the sun gear and runs around the sun gear while rotating in response to rotation of the sun gear; and

a carrier connected to the planetary gear and rotatable about the axis.

23. The apparatus of claim 24, further comprising a gear engaged with the pinion gear and rotatable with the carrier of the first planetary gear stage to transfer torque from the steering wheel to the carrier of the first planetary gear stage.

24. The apparatus of claim 14, further comprising a steering link including a first member rotatably connected to the second output shaft, a second member connected to the first member, and a third member connected to the second member and rotatably connected to the wheel such that rotation of the first member affects steering of the wheel.

25. The apparatus of claim 14, further comprising at least one sensor that generates a signal indicative of a vehicle condition and is connected to a controller operable to control rotation of the first output shaft based on the signal from the at least one vehicle condition sensor.

26. The apparatus of claim 25, wherein the vehicle condition sensor comprises at least one of a torque sensor for detecting torque applied to the steering wheel and a position sensor for detecting a position of the steering wheel.

Technical Field

The present invention relates to a device for rotating a steerable wheel.

Background

Known vehicle steering devices comprise a steering member which is linearly displaceable to effect a steering movement of a steerable wheel. The pinion gear is arranged to mesh with the rack portion of the steering member. A steering column interconnects the pinion gear and a vehicle steering wheel.

Furthermore, such known steering devices comprise a ball nut assembly connected to the externally threaded portion of the steering member. A motor is connected to the ball nut assembly. The motor is operable to effect rotation of the ball nut assembly relative to the steering member to provide steering assistance. A steering device having such a general structure is disclosed in U.S. patent No. 7,055,646.

Disclosure of Invention

In one embodiment, an apparatus for turning a steerable wheel includes a steering column having a pinion coupled to a vehicle steering wheel such that rotation of the steering wheel results in rotation of the pinion. The electric power steering unit includes an electric motor having a first output shaft rotatable about an axis. The first planetary gear stage has a first gear reduction ratio and is driven by a first output shaft. The second planetary gear stage is driven by the first planetary gear stage and the pinion gear and has a second gear reduction ratio that is different from the first gear reduction ratio. The second output shaft is driven by the second planetary gear stage and is coupled to the steerable wheel such that rotation of the second output shaft affects steering of the wheel.

In another embodiment, an apparatus for turning steerable wheels includes an electric steering unit having an electric motor with a first output shaft rotatable about an axis, the wheels operatively connected to a steering wheel by a pinion rotatable by the steering wheel. The gearbox includes a first planetary gear stage having a first gear reduction ratio and driven by a first output shaft. The second planetary gear stage is driven by the first planetary gear stage and the pinion gear. The second planetary gear stage has a second gear reduction ratio that is different from the first gear reduction ratio. The second output shaft is driven by the second planetary gear stage and is coupled to the steerable wheel such that rotation of the second output shaft affects steering of the wheel. The controller controls rotation of the first output shaft in response to rotation of the steering wheel.

Drawings

The above and other features and advantages of the present invention will become apparent to those skilled in the art to which the present invention relates upon reading the following description with reference to the accompanying drawings, in which:

FIG. 1 is a schematic view of an embodiment of an apparatus for rotating a steerable wheel;

FIG. 2A is a front view of the motor and gearbox of the device shown in FIG. 1;

FIG. 2B is a cross-sectional view taken along line 2B-2B of FIG. 2A;

FIG. 2C is a cross-sectional view taken along line 2C-2C of FIG. 2A with a portion of the gearbox removed for clarity;

FIG. 3 is an exploded view of a portion of the gearbox shown in FIG. 2A;

FIG. 4 is a front perspective view of another embodiment of a motor and gearbox for rotating a steerable wheel;

fig. 5 is a rear perspective view of the motor and gear box shown in fig. 4.

Detailed Description

The present invention relates to a device for rotating a steerable wheel. One embodiment of an apparatus 10 for rotating a steerable wheel 12 is shown in fig. 1. The device 10 may be used in a commercial vehicle. The apparatus 10 includes a steering column 20 and an electric power steering unit (EPS unit) 60 for providing steering assist. The steering column 20 extends from a first end 22 to a second end 24. A steering wheel 30 is connected to the first end 22. A pinion gear 32 is connected to or disposed on the second end 24. Rotation of the steering wheel 30 transmits force to the pinion gear 32 via the steering column 20. In other words, the pinion gear 32 rotates under the influence of the force transmitted via the steering column 20.

The steering linkage 40 is connected to steerable wheels 12. As shown, the steering link 40 includes a first steering member 42, a second steering member 52, and a third steering member 54. The first steering member 42 is connected to an output shaft 140 of the EPS unit 60. The first steering member 42 may be a link arm, for example. The second steering member 52 is connected to the first steering member 42 and may be, for example, a tie rod. The third steering member 54 is connected to the second steering member 52 and one of the steered wheels 12. The third steering member 54 may be a steering arm, for example.

The EPS unit 60 provides steering assistance by affecting movement of the steering link 40, and thus steerable wheels 12, in response to rotation of the steering wheel 30. With further reference to fig. 2A-2B, the EPS unit 60 includes a reversible electric motor 62 and a gear box 70 connected to the motor. The motor 62 has an output shaft 64 (see fig. 3) that extends into a gearbox 70. The gearbox 70 includes a housing 72 having a passage 73, the passage 73 extending generally along an axis 74 and completely through the housing. Teeth 76 are provided on the housing 72 along the length of the channel 73 and extend circumferentially about the axis 74.

As shown in fig. 2C, the pinion gear 32 is supported in the housing 72 by a pair of bearings 36. The cap 38 is connected to the housing 72 and receives the second end 24 of the steering column 20 in a manner that allows relative rotation therebetween. Torsion bar 26, output shaft 31 and coupling 33 help to transfer rotation of second end 24 of steering column 20 (acting as an input shaft) to pinion 32. The parts 24, 26, 31, 32, 33 are coaxial with each other.

Torsion bar 26 extends within second end 24 of steering column 20 and output shaft 31. First end 27 of torsion bar 26 is fixed for rotation with second end 24. Second end 29 of torsion bar 26 is fixed for rotation with output shaft 31. When second end 24 is rotated by steering wheel 30, torsion bar 26 allows a predetermined degree of relative rotation to occur between second end 24 and output shaft 31 before the second end rotates with output shaft 31. The coupling 33 is connected to the output shaft 31 for transmitting the rotation of the output shaft to the pinion 32.

With further reference to fig. 3, the first and second planetary gear stages 80, 100 are positioned within the housing 72 and aligned along the axis 74. The first and second stages 80, 100 are connected in series with each other. The output shaft 64 of the motor 62 extends along the axis 74 toward the first stage 80.

The first planetary gear stage 80 includes a sun gear 82 that is fixed to the output shaft 64 and rotatable therewith. The planet gears 84 mesh with the sun gear 82 and the teeth 76 on the housing 72. In a manner R to rotate the sun gear 82₁Rotating the output shaft 64 causes the planet gears 84 to rotate and orbit the sun gear while remaining in mesh with the teeth 76. Although three planet gears 84 are shown, the first planetary gear stage 80 may include more or fewer planet gears.

The planet gears 84 are rotatably supported on a carrier 86, the carrier 86 being rotatable in a manner R that rotates with the planet gears and orbits around the sun gear 72₁Rotating about axis 74. The bracket 86 is radially spaced from the housing 72. The first planetary gear stage 80 may have a gear reduction ratio r from the sun gear 82 to the carrier 86₁For example, a ratio of about 75:1 to about 500: 1.

The second planetary gear stage 100 includes a sun gear 102 that is fixed to the carrier 86 of the first planetary gear stage 80. The sun gear 102 is rotatable with the carrier 86 about the axis 74. The planet gears 104 mesh with the sun gear 102 and the teeth 76 on the housing 72. With R₁Thereby causing the planet gears 104 to rotate and orbit about the sun gear while maintaining engagement with the teeth 76. Although three planet gears 104 are shown, the second planetary gear stage 100 may include more or fewer planet gears.

The planet gears 104 are rotatably supported on a carrier 106, the carrier 106 rotating with the planet gears and running around the sun gear 102 in a manner R₁Rotating about axis 74. The bracket 106 is radially spaced from the housing 72. The second planetary gear stage 100 may haveWith a gear reduction ratio r from the sun gear 102 to the carrier 106₂For example, a ratio of about 15:1 to about 22: 1. It should be appreciated that the gearbox 70 may include additional planetary gear stages (not shown) to achieve a desired gear reduction ratio through the gearbox.

Bushing 120 is connected to housing 72 and is centered about axis 74 at the end of passage 73 opposite motor 62. Bearing 122 is mounted in bushing 120 and is movable relative to the bushing about axis 74 in a manner R₁And (4) rotating. The output shaft 140 is mounted in the bearing 122. The output shaft 140 includes a smooth portion 144 that is fixed to the bearing 122. Splined portion 142 is connected to carrier 106 of second planetary gear stage 100 such that carrier and output shaft 140 are in pattern R₁Rotating together about axis 74. The output shaft 140 also includes a projection 146 for connection to the steering link 40.

Gear 148 is fixed to carrier 86 of first planetary gear stage 80 and can be shifted in manner R₁Rotating with it. The gear 148 also meshes with the pinion gear 32 (see fig. 2C) on the steering column 20. As a result, the rotation of the steering wheel 30 is transmitted to the gear 148 through the pinion gear 32. The pinion gear 32 and the gear 148 may have a gear reduction ratio r₃。

The apparatus 10 (see fig. 1) also includes a controller 150 and one or more vehicle condition sensors that cooperate to control the EPS unit 60 based on detected vehicle conditions. In one embodiment, the vehicle condition sensors may include a torque sensor 152 and a position sensor 154 connected to the controller 150. The torque sensor 152 detects torque applied to the steering wheel 30 and generates a signal indicative of the torque. The position sensor 154 detects the rotational position of the steering wheel 30 and generates a signal indicative of the steering wheel position. It should be understood that one or both of the sensors 152, 154 may be positioned within the hat section 38 (see fig. 2C) or along the steering column 20.

Signals from the torque sensor 152 and the position sensor 154 are sent to the controller 150. The controller 150 analyzes the outputs of the sensors 152, 154 and affects the operation of the motor 62 of the EPS unit 60 as the sensor output. It is also contemplated that only the torque sensor 152 or only the position sensor 154 may be used to affect the operation of the motor 62. The controller 150 may also have inputs (not shown) or other vehicle operating conditions that vary as a function of the detected lateral acceleration of the vehicle. In any event, the signals received by the controller 150 determine the speed and/or torque of the motor 62, and thus the speed and torque transmitted by the output shaft 64 to the gearbox 70, to assist in steering the steerable wheels 12.

During operation, the operator rotates the steering wheel 30 and thereby rotates the pinion gear 32. This in turn is at a first speed S₁And a first torque T₁In the mode R₁Rotating gear 148 about axis 74. As described above, the gear reduction ratio r₃Determines the relationship between the rotation of the steering wheel 30 and the rotation of the gear 148.

At the same time, the controller 150 actuates the motor 62 at the desired second speed S in response to signals received by at least one of the sensors 152, 154₂And a second torque T₂In the mode R₁Rotating the output shaft 64. At the carrier 86, the second speed S of the output shaft 64₂Due to the gear reduction ratio r of the first planetary gear stage 80₁And is reduced to the first speed S₁. In other words, the controller 150 ensures the gear reduction ratio r₁To select the second speed S₂Such that the carrier 86 has the same first speed S as the input gear 148 secured thereto₁And (4) rotating. Thus, controller 150 coordinates the rotation of output shaft 64 with the rotation of steering wheel 30.

At the carrier 86, the second torque T of the output shaft 64₂Due to the gear reduction ratio r₁And increases to the third torque T₃. As a result, the sun gear 102 of the second planetary gear stage 100, which is fixed to the carrier 86, and the input gear 148 are at the first speed S₁To equal the first torque T₁And a third torque T₃Fourth torque T of the sum₄Mode (II) R₁And (4) rotating.

At the carrier 106, the first speed S of the sun gear 102₁Due to the gear reduction ratio r of the second planetary gear stage 100₂And decreases to a third speed S₃. At the carrier 106, the sun gear 102Fourth torque T₄Due to the gear reduction ratio r₂And increases to a fifth torque T₅. As a result, the output shaft 140 fixed to the carrier 106 is at the third speed S₃To accompany the fifth torque T₅Mode (II) R₁And (4) rotating.

As can be seen from the above, the first speed S transmitted from the steering wheel 30 to the gear box 70 via the pinion gear 32_lDue to the reduction ratio r₁And r₃The product of (c) decreases. First torque T transmitted by steering wheel 30 to gearbox 70₁Due to the gear reduction ratio r₁And r₃The product of (a) increases. A second speed S transmitted by the output shaft 64 of the motor 62 to the gearbox 70₂Due to the gear reduction ratio r₂And r₃The product of (c) decreases. Second torque T transmitted by the output shaft 64 of the motor 62 to the gearbox 70₂Due to the gear reduction ratio r₂And r₃The product of (a) increases. Gear reduction ratio r₁To r₃Together producing a desired third speed S at the output shaft 140₃And a fifth torque T₅。

When the output shaft 140 is at the third speed S, as shown in FIG. 1₃And a fifth torque T₅In the mode R₁While rotating, the first steering member 42 fixed thereto is likewise rotated at the third speed and the fifth torque in the manner R₁And (4) rotating. The first steering member 42 moves the second steering member 52 in the manner L, which is in the manner R₂The third steering member 54 is pivoted to steer the wheels 12. Thus, the EPS unit 60 relies on the mechanical advantage of the gearbox 70 to reduce the speed of the motor 62 and steering wheel 30 while increasing the torque provided thereby to provide steering assistance to the vehicle operator.

With this configuration of the gear box 70 and gear 148, the device 10 is able to provide feedback or steering feel to the operator. In other words, the gear box 70 can provide the steering wheel 30 with a relatively low gear reduction ratio r₃While at the same time passing through a higher reduction ratio r₁、r₂Steering assist is provided to the steering linkage 40. For this purpose, the gear reduction ratio r₃Such that the operator's turning of the steering wheel 30 is within a predetermined range, for example, from the locked position to the locked position.

In another embodiment, as shown in fig. 4-5, a plurality of motors are connected to the gearbox to affect the steering assist of the steerable wheels. Components in fig. 4 to 5 are given the same reference numerals if they are the same as components in fig. 1 to 3, and similar components are given the suffix "a".

As shown in fig. 4-5, two reversible motors 62a are secured to opposite sides of a housing 72a of a gear box 70 a. The output shaft 64 of each motor 62a is connected to a drive belt 170. Drive belt 170 is connected to an input shaft 180, with input shaft 180 being fixed to sun gear 82 of first planetary gear stage 80. When both motors 62a are actuated, drive belt 170 transfers torque from each motor to gear box 70 a. It should be understood that instead of two motors 62a acting simultaneously, one of the two motors may be deactivated and used only for redundancy/backup. In any case, the drive belt 170 may have a meshed/toothed connection with the output shaft 64 and/or the input shaft 180 to help mitigate slippage.

During operation, the operator rotates the steering wheel 30, thereby rotating the pinion gear 32. This in turn is at a first speed S₁And a first torque T₁In the mode R₁Rotating the input gear 148 about the axis 74 a. Gear reduction ratio r₃Determines the relationship between the rotation of the steering wheel 30 and the rotation of the input gear 148.

Meanwhile, the controller 150 actuates the two motors 62a at the second speed S in response to signals received by at least one of the sensors 152, 154₂And a second torque T₂Rotate about respective axes 66. The drive belt 170 transmits the rotation of the two motors 62a to the input shaft 180, causing the input shaft and the sun gear 82 fixed thereto to rotate at a second speed S₂To be equal to the second torque T₂Twice the sixth torque T₆And (4) rotating.

Thereafter, the planetary gear stages 80, 100 cooperate with the sun gear 82 and the gear 148 to adjust the speed and torque thereof, as previously described, to provide the output shaft 140 with the speed and torque required to assist in steering the wheels 12. More specifically, at the carrier 86, the second speed S of the sun gear 82₂Through the teeth of the first planetary gear stage 80Wheel reduction ratio r₁Reduced to a first speed S₁. The controller 80 ensures that the first speed S is based on₁And a gear reduction ratio r₁While selecting the second speed S₂Such that the carrier 86 has the same first speed S as the input gear 148 secured thereto₁In the mode R₁And (4) rotating. Thus, the controller 80 coordinates rotation of the input shaft 180 with rotation of the steering wheel 30.

Sixth torque T of input shaft 180 at carrier 86₆Due to the gear reduction ratio r₁And increases to a seventh torque T₇. As a result, the sun gear 102 of the second planetary gear stage 100, which is fixed to the carrier 86, and the input gear 148 are at the first speed S₁To equal the sixth torque T₆And a seventh torque T₇Eighth torque T of the sum₈In the mode R₁And (4) rotating.

At the carrier 106, the first speed S of the sun gear 102₁Due to the gear reduction ratio r of the second planetary gear stage 100₂And decreases to a third speed S₃. An eighth torque T of the sun gear 102 at the carrier 106₈Due to the gear reduction ratio r₂And increased to the ninth torque T₉. As a result, the output shaft 140 fixed to the carrier 106 is at the third speed S₃At a ninth torque T₉In the mode R₁And (4) rotating. In one embodiment, the ninth torque T associated with the gearboxes 70a of the two motors 62a₉Greater than the fifth torque T associated with the gearbox 70 of the single motor 62₅. Therefore, the gearbox 70a can provide steering assist for a larger vehicle than the gearbox 70.

What has been described above is an embodiment of the present invention. It is, of course, not possible to describe every conceivable combination of components or methodologies for purposes of describing the present invention, but one of ordinary skill in the art may recognize that many further combinations and permutations of the present invention are possible. Accordingly, the present invention is intended to embrace all such alterations, modifications and variations that fall within the spirit and scope of the appended claims.