LEVEL ADJUSTMENT DEVICE FOR A MOTOR VEHICLE

Abstract

A device for adjusting the level of a motor vehicle comprises an electric motor (4) and an actuating gear (3) which is connected upstream of a screw drive (2). The actuating gear (3) is formed by three series-connected gears (14, 15, 16) with parallel rotation axes (D14, D15, D16). An input gear (14), the number of teeth of which is at least one and at most five, is coupled to the motor shaft (17) of the electric motor (4) for conjoint rotation. The input gear engages with an intermediate gear (15) which engages with an output gear (16) which is connected to a nut (9) of the screw drive (2) for conjoint rotation.

Claims

1. An electromechanical level control device for a motor vehicle, having an electric motor with a shaft and an actuating gear which is connected upstream of a screw drive, wherein the actuating gear is formed by three series-connected gears having mutually parallel rotation axes, wherein an input gear having at least one and at most five teeth is coupled to the motor shaft of the electric motor for conjoint rotation and engages with an intermediate gear which engages with an output gear which is connected to a nut of the screw drive for conjoint rotation.

2. The level control device according to claim 1, wherein the three gears are helical gears.

3. The level control device according to claim 2, wherein the three gears have a KAT t helix angle to achieve a total contact ratio of more than 1.

4. The level control device according to claim 1, wherein axis of rotation of the intermediate gear intersects a stator of the electric motor.

5. The level control device according to claim 4, wherein housing element of the actuating gear has a hole and a cone, wherein a bearing outer ring for mounting the input gear is held in the hole and at least one bearing inner ring of a bearing of the intermediate gear is held on the cone.

6. The level control device according to claim 1, wherein two housing elements of the actuating gear each have a hole in which a bearing outer ring of a roller bearing for supporting the input gear is held, and one of these housing elements has a cone on which at least one bearing inner ring of a bearing of the intermediate gear is held.

7. The level control device according to claim 1, wherein a number of teeth of the intermediate gear is smaller than a of teeth of the output gear and larger than the number of teeth of the input gear.

8. The level control device according to claim 1, wherein a total gear ratio of the actuating gear is at least 10 and at most 100.

9. The level control device according to claim 1, wherein the output gear directly encloses the nut of the screw drive and the screw drive is a ball screw drive.

10. A level control device for a motor vehicle comprising: an electric motor having a motor shaft supported to rotate about a motor shaft axis; a screw drive having an axis parallel to the motor shaft axis; an input gear fixed to the motor shaft and having at least one and at most five teeth; an intermediate gear engaged with the input gear and supported for rotation about an axis parallel to the motor shaft axis; and an output gear engaged with the intermediate gear and fixed to a nut of the screw drive.

11. The level control device according to claim 10, wherein the input gear, intermediate gear, and output gear are all helical gears with a helix angle.

12. The level control device according to claim 11, wherein the helix angle is sufficient to achieve a total contact ratio of more than 1.

13. The level control device according to claim 10, wherein the axis of rotation of the intermediate gear intersects a stator of the electric motor.

14. The level control device according to claim 13, wherein a housing element has a hole and a cone, wherein a bearing outer ring for mounting the input gear is held in the hole and at least one bearing inner ring of a bearing of the intermediate gear is held on the cone.

15. The level control device according to claim 10, wherein two housing elements each have a hole in which a bearing outer ring of a roller bearing for supporting the input gear is held, and one of these housing elements has a cone on which at least one bearing inner ring of a bearing of the intermediate gear is held.

16. The level control device according to claim 10, wherein the intermediate gear has more teeth than the input gear and fewer teeth than the output gear.

17. The level control device according to claim 10, wherein a ratio of a number of teeth of the output gear to the number of teeth of the input gear is at least 10 and at most 100.

18. The level control device according to claim 10, wherein the output gear directly encloses the nut of the screw drive and the screw drive is a ball screw drive.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In what follows, two embodiments are explained in more detail by means of a drawing. Wherein:

[0023] FIG. 1 is a first embodiment of an electromechanical level control device in a sectional view,

[0024] FIG. 2 is a detail of the arrangement according to FIG. 1,

[0025] FIGS. 3 to 5, in different views show gears of an actuating gear of the level control device according to FIG. 1,

[0026] FIG. 6 is a second embodiment of an electromechanical level control device in a representation similar to FIG. 1.

DETAILED DESCRIPTION

[0027] An electromechanical level control device, generally marked with the reference symbol 1, is intended for use in a motor vehicle, in particular a passenger car. With regard to the basic function of the level control device 1, reference is made to the prior art cited at the beginning.

[0028] FIGS. 1 to 5 refer to a leveling control device 1 for the front axle, FIG. 6 refers to a leveling control device 1 for the rear axle of the motor vehicle. Parts that correspond to each other or have basically the same effect are marked with the same reference symbols in all figures. Unless otherwise stated, the following explanations refer to both exemplary embodiments.

[0029] The level control device 1 comprises a screw drive 2, namely a ball screw drive, which is operated by an electric motor 4 through an actuating gear 3, which is described in more detail below. A housing 5 of the actuating gear 3 is firmly connected to a spring plate 6 and a sleeve 7. A roller bearing 8 is supported on the sleeve 7 and on the housing 5, which in this case is designed as an angular contact roller bearing and serves to support a nut 9, which is part of the screw drive 2. During operation of the screw drive 2, balls roll on a helically wound ball track 10 of the nut 9, and simultaneously contact a hollow threaded spindle 11 also belonging to the screw drive 2. The threaded spindle 11 is movably but not rotatably guided in the sleeve 7 and firmly connected to a damper tube 12. The bellows 13 serves to secure the seal between the damper tube 12 and the housing 5.

[0030] The actuating gear 3 is designed as a three-gear chain consisting of an input gear 14, an intermediate gear 15 and an output gear 16. The rotation axes of the three gears 14, 15, 16 are marked D14, D15 and D16. The axis of rotation D14 of the input gear 14 is identical to the axis of the electric motor 4. The motor shaft of the electric motor 4, marked 17, is coupled to the input gear 14 via coupling 18 for conjoint rotation. A coupling element marked 19, which is to be assigned to the coupling 18, is firmly connected to the input gear 14 or is identical to it. The coupling element 19 is supported by a ball bearing 20 in the housing 5. An outer ring 21 of the ball bearing 20 is inserted into a hole 22, which is formed in a housing element 23 of the housing 5. A further ball bearing 24 is provided for the bearing the motor shaft 17. Alternatively, the function of the two ball bearings 20, 24 can be taken over by a single bearing, especially roller bearings. The end of the input gear 14 facing away from the electric motor 4 is supported in the housing 5 by a further ball bearing 25. Thus the two ball bearings 20, 25 are each positioned in front of one face of the input gear 14.

[0031] The input gear 14 is designed as a helical gear with only three teeth. The intermediate gear 15 driven by the input gear 14 has a comparatively high number of teeth and is mounted on a cone 26, which is formed by the housing element 23 in the embodiment shown in FIG. 1. In the embodiment shown in FIG. 6, on the other, the cone 26 is formed by a housing element 35, which houses the ball bearing 25.

[0032] In both cases there are two roller bearings 27, 28, namely ball bearings, on the cone 26. The inner rings of roller bearings 27, 28 are designated 29, 30, with an intermediate ring 31 located between the two inner rings 29, 30 of roller bearings 27, 28, which keeps them at a defined distance from each other. The associated outer rings 32, 33 of the roller bearings 27, 28 are inserted into a central opening 34 in the intermediate gear 15.

[0033] In the embodiment shown in FIG. 1, the axis of rotation D15 of the intermediate gear 15 only intersects the electric motor 4. On the other hand, the axis of rotation D15 of the intermediate gear 15 passes the electric motor 4 in the case of FIG. 6. In both cases all rotation axes D14, D15, D16 are arranged parallel to each other, wherein the rotation axis D16 of the output gear 16 is identical to the central axis of the damper tube 12 and the sleeve 7. In contrast to the intermediate gear 15, the output gear 16 does not have its own bearing. Instead, the output gear 16 is firmly connected to the nut 9, and directly encloses it.

[0034] The output gear 16 is the largest of the three gears 14, 15, 16. The gear ratio of the actuating gear 3 is given by the ratio between the number of teeth of the output gear 16 and the number of teeth of the input gear 14 and is 70/3=23.33 in the present cases. Within the entire level control system 1, the setting wheel 3 according to FIG. 1 requires only a very small installation space. In the case of FIG. 6, however, the extent of the actuating gear 3 in the radial direction is slightly increased to adapt to an existing surrounding structure. The compact design of the actuating gear 3 in both cases, especially in the axial direction, with respect to the rotation axes D14, D15 and D16, also has the advantage that undesirable forces and tilting moments are largely avoided. It is also particularly robust with regard to the effects of vibrations. The level control device 1 is particularly suitable as a component of a level control system.

LIST OF REFERENCE SYMBOLS

[0035] 1 Level control device [0036] 2 Screw drive [0037] 3 Actuating gear [0038] 4 Electric motor [0039] 5 Housing [0040] 6 Spring plate [0041] 7 Sleeve [0042] 8 Roller bearings [0043] 9 Nut [0044] 10 Ball track [0045] 11 Threaded spindle [0046] 12 Damper tube [0047] 13 Bellows [0048] 14 Input gear [0049] 15 Intermediate gear [0050] 16 Output gear [0051] 17 Motor shaft [0052] 18 Coupling [0053] 19 Coupling element [0054] 20 Ball bearing [0055] 21 Outer Ring [0056] 22 Hole [0057] 23 Housing element [0058] 24 Ball bearing [0059] 25 Ball bearing [0060] 26 Cone [0061] 27 Roller bearing [0062] 28 Roller bearing [0063] 29 Inner Ring [0064] 30 Inner Ring [0065] 31 Intermediate ring [0066] 32 Outer Ring [0067] 33 Outer Ring [0068] 34 Central opening [0069] 35 Housing element [0070] D.sub.14 Rotation axis of the input gear [0071] D.sub.15 Rotation axis of the intermediate gear [0072] D.sub.16 Rotation axis of the output gear