FEEDBACK ACTUATOR FOR A STEERING DEVICE OF A MOTOR VEHICLE

Abstract

A feedback actuator for a steering device of a motor vehicle may include a casing unit that has an outer casing that can be attached to a motor vehicle and an inner casing received therein such that the inner casing is telescopically adjustable in a longitudinal direction, a steering spindle mounted in the inner casing such that the steering spindle is rotatable about a longitudinal axis, and an electric motor of a drive unit arranged in an interior space of the casing unit. The electric motor may have a stator that is fixed on the outer casing and a rotor that can be driven rotationally. A rotor shaft may be coaxial with respect to the longitudinal axis and coupled via a gear mechanism to the steering spindle.

Claims

1.-11. (canceled)

12. A feedback actuator for a steering device of a motor vehicle, the feedback actuator comprising: a casing unit having an outer casing that is attachable to the motor vehicle, and an inner casing that is received in the outer casing such that the inner casing is telescopically adjustable in a longitudinal direction; a steering spindle mounted in the inner casing such that the steering spindle is rotatable about a longitudinal axis; and an electric motor of a drive unit disposed in an interior space of the casing unit, wherein the electric motor includes a stator that is fixed on the outer casing, and a rotor that is configured to be driven rotationally and has a rotor shaft that is coupled via a gear mechanism to the steering spindle.

13. The feedback actuator of claim 12 wherein at least some sections of the outer casing are tubular.

14. The feedback actuator of claim 12 wherein at least some sections of the inner casing are tubular.

15. The feedback actuator of claim 12 wherein the electric motor has an outer cross section that is smaller than an inner cross section of the inner casing.

16. The feedback actuator of claim 12 wherein a coaxial intermediate space is configured between the electric motor and the outer casing, wherein the coaxial intermediate space is configured to receive the inner casing.

17. The feedback actuator of claim 12 wherein the drive unit is coupled to the steering spindle via a shaft arrangement, wherein a length of the shaft arrangement is variable in the longitudinal direction.

18. The feedback actuator of claim 12 wherein the electric motor is disposed in an end region of the outer casing, wherein the end region faces away from the inner casing in the longitudinal direction.

19. The feedback actuator of claim 12 wherein the gear mechanism is disposed at least partially outside the interior space of the outer casing.

20. The feedback actuator of claim 12 wherein the gear mechanism is attached to the outer casing on an end side.

21. The feedback actuator of claim 12 wherein the rotor shaft is configured as a hollow shaft, wherein an output shaft of the gear mechanism or the steering spindle is guided coaxially through the hollow shaft and is coupled to the steering spindle.

22. The feedback actuator of claim 12 wherein the gear mechanism has a transmission ratio of between 1:3 and 1:25.

23. The feedback actuator of claim 12 comprising a motorized adjustment drive disposed between the inner casing and the outer casing.

Description

DESCRIPTION OF THE DRAWINGS

[0028] Advantageous embodiments of the invention will be explained in greater detail in the following text on the basis of the drawings, in which, in detail:

[0029] FIG. 1 shows a steering device for a motor vehicle with a feedback actuator according to the invention in a diagrammatic perspective view,

[0030] FIG. 2 shows the steering device according to FIG. 1 in a further perspective view,

[0031] FIG. 3 shows a longitudinal section through a steering device according to FIG. 1 or 2,

[0032] FIG. 4 shows the steering device in a perspective view as in FIG. 2, in a partially open diagrammatic illustration, and

[0033] FIG. 5 shows the steering device in a perspective view as in FIG. 1, in a partially open diagrammatic partial illustration.

EMBODIMENTS OF THE INVENTION

[0034] In the different figures, identical parts are always provided with the same designations, and are therefore also as a rule named or mentioned in each case only once.

[0035] FIGS. 1 and 2 diagrammatically show perspective outside views of a steering input apparatus 1 for a motor vehicle (not shown) in the form of an adjustable-length steering column which has a feedback actuator 2 according to the invention. In detail, FIG. 1 shows a view obliquely from rear left (in relation to the driving direction), and FIG. 2 shows a view obliquely from front left, that is to say on the same side counter to the driving direction.

[0036] The feedback actuator 2 has a casing unit 3, with a substantially tubular outer casing 31 (also called an outer casing tube or guide bracket) which is open toward the rear and in which a tubular inner casing 32 (also called an inner casing tube or an inner casing) is received coaxially with respect to a longitudinal axis L, which inner casing 32 can be displaced in the direction of a central longitudinal axis L in the longitudinal direction or in an axially telescopic manner, as indicated by way of a double arrow.

[0037] A steering spindle 33 is mounted in a bearing 34 such that it can be rotated about the longitudinal axis L in the inner casing 32. At the rear end which faces the driver's position, the steering spindle 33 has a receiving section 35 for attaching a steering wheel (not shown).

[0038] The steering spindle 33 is configured as a variable-length shaft with an inner shaft 36 which has the receiving section 35 and is mounted in the bearing 34, which inner shaft 36 dips into a hollow shaft 37 in a torque-transmitting and axially displaceable manner. The inner shaft 36 and the hollow shaft 37 can have corresponding non-round cross sections or longitudinal spline systems for the transmission of torque in a manner known per se.

[0039] A supporting unit 4 has fastening openings 41 for fastening to a vehicle body (not shown) of the vehicle. In its front region, the outer casing 31 is connected to the supporting unit 4 such that it can be pivoted about a horizontal pivot axis S which lies transversely with respect to the longitudinal axis L. In the rear region, a pivoting lever 42 is articulated on the outer casing 31 and the supporting unit 2, with the result that pivoting of the casing unit 3 relative to the supporting unit 4 is made possible, a height adjustment of the steering wheel which is attached to the receiving section 35 being made possible in the height direction H, as indicated by way of the double arrow.

[0040] A length adjustment drive 5 which is configured as a linear plunger spindle drive in the example which is shown comprises a spindle nut 52 which can be driven rotationally by an actuating motor 51, is supported in the longitudinal direction on the outer casing 31, and into which a threaded spindle 53 engages which is arranged parallel to the longitudinal axis L and is supported in the longitudinal direction on the inner casing 32. By way of relative rotation by means of the actuating motor 51, the threaded spindle 53 and the spindle nut 52 are moved in the longitudinal direction relative to one another, as a result of which the inner casing 32 can be retracted or extended in a telescoping manner for length adjustment.

[0041] FIG. 5 shows a longitudinal section through the casing unit 3. An electric motor 6 of the feedback actuator 2 has a stator 61 which coaxially surrounds a rotor 62 which can be driven rotationally therein. The rotor 62 has a rotor shaft 63 which is configured as a hollow shaft and is arranged coaxially with respect to the longitudinal axis L. The motor 6 is connected to the casing unit 3 by virtue of the fact that the stator 62 is fixed in the longitudinal direction coaxially in the front region interior space of the outer casing 31 and in a non-rotational manner with regard to rotation about the longitudinal axis L.

[0042] At the rear end, a gear mechanism 7 is fastened on the end side outside the interior space to the outer casing 31. The gear mechanism 7 has a gear mechanism housing 71 which, as shown, is fastened on the front axial opening of the outer casing. Here, as in the example which is shown, the stator 61 can be connected axially to that end wall of the housing 71 which faces the outer casing 31, as a result of which the motor 6 is positioned and fixed in the interior space. The steering spindle 33 is arranged rotatably within the rotor shaft 63, the hollow shaft 37 being guided axially through the rotor shaft 63 without contact of the rotor shaft 63 and the hollow shaft 37 occurring.

[0043] The rotor shaft 63 projects rearward axially out of the interior space of the outer casing 31, and is coupled to an input gear 72 of the gear mechanism 7, which input gear 72 is mounted coaxially with respect to the longitudinal axis L and is configured as a spur gear. It can be seen from the diagrammatic perspective illustrations of FIGS. 3 and 4, in which the gear mechanism housing 71 is omitted for improved clarity, that the input gear 72 meshes with a first intermediate gear 73 which is mounted eccentrically from the longitudinal axis L and is connected fixedly for conjoint rotation to a second intermediate gear 74 with a lower number of teeth, which second intermediate gear 74 engages into an output gear 75.

[0044] The output gear 75 is mounted coaxially with respect to the longitudinal axis L, and is coupled in a torque-transmitting manner to the steering spindle 33 via the hollow shaft 37.

[0045] A rotation of the rotor 62 by way of actuation of the motor 6 is converted via the gear mechanism 7 into a stepped-down, slower rotation of the output gear 75 and therefore of the steering spindle 33. The transmission ratio which is determined by way of the numbers of teeth of the gear wheels 72, 73, 74 and 75 can lie in the range from 1:3 to 1:25, preferably in the range from 1:5 to 1:15. As can be seen from the examples which are shown, the gear mechanism 7 has an outer cross section which is greater than the inner cross section of the outer casing 31. Here, a compact shape and an optimized adaptation to the installation space which is available in the motor vehicle can nevertheless take place by way of the integration of the motor 6 into the interior space of the outer casing 31 and the end-side arrangement of the gear mechanism 7.

[0046] The stator 61 and therefore the motor 6 preferably have an external diameter d which is smaller than the internal diameter D of the inner casing 32, with the result that the motor 6 has an outer cross section which is smaller than an inner cross section of the inner casing 31. As a result, during contraction of the casing unit 3, that is to say from left to right in FIG. 5, the inner casing 32 can dip in the longitudinal direction into the coaxial intermediate space 38 which is formed between the motor 6 and the inner wall of the outer casing 31. As a result, a short stowage length can be realized.

[0047] The gear mechanism housing 71 can be connected releasably or non-releasably to the outer casing 31. The connection can take place by means of an integrally joined and/or positively locking and/or non-positive connection.

[0048] An electric control unit 8 for actuating the motor 6 can be attached to the gear mechanism housing 71. It can additionally be provided that the control unit 8 likewise actuates the length adjustment drive 5.

[0049] For height adjustment in the vertical direction H, a height adjustment drive 9 can be provided which in principle can be of similar configuration to the length adjustment drive 5 as a spindle drive, and can act, for example, between the outer casing 31 and the pivoting lever 42, or in some other way between the casing unit 3 and the supporting unit 4.

LIST OF DESIGNATIONS

[0050] 1 Steering input apparatus [0051] 2 Feedback actuator [0052] 3 Casing unit [0053] 31 Outer casing [0054] 32 Inner casing [0055] 33 Steering spindle [0056] 34 Bearing [0057] 35 Receiving section [0058] 36 Inner shaft [0059] 37 Hollow shaft [0060] 38 Intermediate space [0061] 4 Supporting unit [0062] 41 Fastening opening [0063] 42 Pivoting lever [0064] 5 Length adjustment drive [0065] 51 Actuating motor [0066] 52 Spindle nut [0067] 53 Threaded spindle [0068] 6 Motor [0069] 61 Stator [0070] 62 Rotor [0071] 63 Rotor shaft [0072] 7 Gear mechanism [0073] 71 Gear mechanism housing [0074] 72 Input gear [0075] 73,74 Intermediate gear [0076] 75 Output gear [0077] 8 Control unit [0078] 9 Height adjustment drive [0079] D, d External diameter [0080] L Longitudinal axis [0081] S Pivot axis