DE102017103976A1 - Anti-rotation of the rack by complementary shapes - Google Patents

Abstract

A steering system for steering a wheel of a vehicle is provided, comprising: a tie rod (11) for deflecting the wheel, a rack (4), which leads by an axial displacement to control the tie rod (11), and a housing ( 3), wherein the rack (4) is at least partially disposed within the housing, wherein the rack (4) has a convex or concave cross-sectional portion, wherein the housing (3) comprises a complementary concave or convex shape, whereby a positive connection to Realization of an anti-rotation results.

Description

FIELD OF THE INVENTION

The present invention relates to a steering system and a vehicle.

BACKGROUND OF THE INVENTION

In the prior art pinion rack assemblies and ball screws are known as part of a steering system.

SUMMARY OF THE INVENTION

The term "rack" is synonymously understood as a handlebar. A rack is axially displaceable, where it can turn over tie rods articulated wheels of vehicles.

A steering with a ball screw has the disadvantage that, in contrast to a steering with pinion rack assembly no inherent rotation of the rack is present. An anti-rotation is necessary for the function of the ball screw. Is in a steering, for example, a steer-by-wire steering, for applying the steering torque exclusively a ball screw before, therefore, an additional anti-rotation must be arranged.

In a classic steering system with Schraubradgetriebe by means of a pinion rack assembly automatically results in a rotation of the respective rack, as usually arranged opposite the pinion thrust piece ensures that the rack is pressed with its teeth against the teeth of the pinion and thus a Spielarmut with respect to a rotation of the rack is present. Even without a pressure piece a rotation is given only in the context of the backlash between the teeth partners pinion and rack. In a steer-by-wire steering with ball screw such a rotation is not given, since in this case eliminates the steering gear in the form of a pinion rack and pinion.

One object is therefore to provide a steering system for a "steer by wire" concept with a ball screw drive, which enables an anti-twist device.

As a first embodiment of the invention, there is provided a steering system for steering a wheel of a vehicle, comprising: a tie rod for deflecting the wheel, a rack leading by an axial displacement for controlling the tie rod, and a housing, the rack being at least partially is disposed within the housing, wherein the rack has a convex or concave cross-sectional portion, wherein the housing comprises a complementary concave or convex shape, resulting in a positive connection for realizing an anti-rotation.

Corresponding characteristics of the rack to its housing, for example in a trefoil profile, a rotation of the rack can be ensured within the housing.

As a second embodiment of the invention, a vehicle is provided, wherein the vehicle has a steering system according to one of claims 1 to 9.

Exemplary embodiments are described in the dependent claims.

According to an exemplary embodiment of the invention, a steering system is provided, wherein between the housing and the rack, an intermediate element is arranged to ensure a friction and low-wear sliding friction, a fitting accuracy and a Spielarmut or backlash.

According to a further embodiment of the present invention, a steering system is provided, wherein between the housing and intermediate element, an insert sleeve is present, which is connected to the housing.

In a further embodiment of the invention, a steering system is provided, wherein the intermediate member is formed integrally with the housing or integrally with the insert sleeve or integrally with the rack.

By a one-piece construction a simplified assembly of the steering is given.

According to another embodiment of the present invention, a steering system is provided, wherein the intermediate element between the housing and rack is injected or inserted.

This results in a simple mounting option.

According to an exemplary embodiment of the invention, a steering system is provided, wherein the intermediate element in the radial and / or in the axial direction has a waveform, in particular a sinusoidal waveform.

By a sinusoidal design of the intermediate element a simplified production of the intermediate element is possible.

In a further embodiment of the invention, a steering system is provided, wherein the steering system is suitable for highly autonomous driving. According to a further embodiment of the present invention, a steering system is provided, wherein the steering system is suitable for steer-by-wire and / or wherein the steering system is suitable as a rear axle steering.

In another embodiment of the invention, a steering system is provided wherein metallic protrusion of the housing or rack protrudes into a mating metallic recess of the rack or housing.

By a metallic nose, which projects into a complementary recess, an emergency rotation can be realized.

As an idea of the invention can be considered to provide a steering system in which the rack has a contour such that a rotation of the rack can be excluded by a positive connection with the enclosure of the rack, so its housing.

Of course, the individual features can also be combined with each other, which can also be partially beneficial effects that go beyond the sum of the individual effects.

list of figures

• 1 einen Abschnitt einer Zahnstange 4 in einem Gehäuse 3 in einer perspektivischen Schnittdarstellung,
• 2 einen perspektivischen Querschnitt der Zahnstange 4 in dem Gehäuse 3,
• 3 einen weiteren Abschnitt der Zahnstange 4 in einem Gehäuse 3 in einer perspektivischen Schnittdarstellung,
• 4 einen weiteren perspektivischen Querschnitt der Zahnstange 4 in einem Gehäuse 3,
• 5 eine weitere schematische Schnittdarstellung der Zahnstange 4 in einem Gehäuse 3 und einem Zwischenelement 5, beispielsweise mit Wellenform,
• 6 einen weiteren perspektivischen Längsschnitt durch die Zahnstange 4 mit einem Gehäuse 3,
• 7 einen Querschnitt mit der Zahnstange 4 und dem Gehäuse 3, wobei zwischen Zahnstange 4 und Gehäuse 3 ein Zwischenelement 5 mit einem Kleeblattprofil angeordnet ist,
• 8 das Zwischenelement 5 und
• 9 eine schematische Darstellung eines Lenksystems eines Fahrzeugs.

Further details and advantages of the invention will become apparent from the embodiments illustrated in the drawings. Show it

• 1 a section of a rack 4 in a housing 3 in a perspective sectional view,
• 2 a perspective cross section of the rack 4 in the housing 3,
• 3 a further section of the rack 4 in a housing 3 in a perspective sectional view,
• 4 a further perspective cross section of the rack 4 in a housing 3,
• 5 FIG. 2 a further schematic sectional view of the rack 4 in a housing 3 and an intermediate element 5, for example with a waveform,
• 6 a further perspective longitudinal section through the rack 4 with a housing 3,
• 7 a cross section with the rack 4 and the housing 3, wherein between rack 4 and housing 3, an intermediate element 5 is arranged with a trefoil profile,
• 8th the intermediate element 5 and
• 9 a schematic representation of a steering system of a vehicle.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

1 shows a longitudinal section of the rack 4 with the housing 3 , being between the case 3 and the rack 4 an intermediate element 6 is arranged, which is a better tribological behavior, thus reducing the friction and wear, between the rack 4 and the housing 3 allows. The insert shown 10 is alternatively available and the housing 3 belong. By means of this insert bush 10 may be the assembly and / or attachment of the intermediate element 6 on the housing 3 be relieved, if the intermediate element 6 is fixed to the housing and the sliding movement between the rack 4 and the intermediate element 6 he follows. Alternatively, the intermediate element 6 also stuck to the rack 4 be connected, in which case the sliding movement between the housing 3 and / or the housing-fixed insert socket 10 and the intermediate element 6 he follows.

2 shows a cross section of the rack 4 , where between rack 4 and the housing 3 an intermediate element 6 is arranged. In particular, an outer contour of the rack 4 and an inner contour of the housing 2 such that there is a form-fitting training that leads to a rotation. Between rack 4 and housing 3 can be an intermediate element 6 be arranged with the housing 3 is firmly connected and that a low-friction sliding friction, with little wear, between rack 4 and housing 3 , make sure. Between housing 3 and intermediate element 6 may additionally be an insert bushing 10 be arranged with the housing 3 is firmly connected. A complementary inner and outer contour pairing can be present, for example, as a nose-recess pairing.

3 shows a longitudinal section with an intermediate element 7 that with the rack 4 is firmly connected. In this embodiment, also a housing-fixed insert bushing is also in addition 10 available. The sliding movement takes place between the housing 3 or insert bushes 10 and the intermediate element 7 instead of.

4 shows a cross section with a rack 4 with which the intermediate element 7 is firmly connected. The speed separation or the sliding movement takes place between the housing 3 or the insert sleeve 10 and the intermediate element 7 instead of.

5 shows an intermediate element 5 , which is characterized by a special contour in the radial direction, resulting in particularly selected points of contact with the rack 9 or with the housing 8th result.

6 shows a longitudinal section with a rack 4 , where between rack 4 and housing 3 an intermediate element 5 is arranged for sliding friction and rotation.

7 shows that between rack 4 and housing 3 inserted intermediate element 5 , The intermediate element 5 is strained so that at specially selected contact points a contact with the rack 4 or with the housing 3 results.

8th shows the intermediate element 5 this may take on a particular waveform in radial and axial alignment to ensure proper contact with the rack and housing.

9 shows a schematic representation of the steering system of a vehicle with the steering column 18 that have a pinion 14 to a movement of the rack 4 along its longitudinal axis leads. The rotation of the pinion 14 is detected via a torque sensor 12 and to a control unit 13 transmitted. The control unit 13 controls the servo motor 17 such that there is a steering assistance. The servomotor 17 drives a belt 15 on, the ball screw 16 controls.

In a conventional steering system with mechanical drive through the pinion rack and pinion connection, the function of anti-rotation of the rack is provided so far automatically. In alternative steering systems, for example, a steer-by-wire steering based on the EPS _apa , without mechanical drive, there is no pinion-rack connection. However, since the function of the rotation of the rack is essential for the functioning of the ball screw, it must be realized otherwise. According to the invention the rotation of the rack is made possible by a positive connection with a corresponding mating contour of the housing of the rack.

It should be noted that the term "comprising" does not exclude other elements or method steps, just as the term "a" and "an" does not exclude multiple elements and steps.

The reference numerals used are for convenience of reference only and are not to be considered as limiting, the scope of the invention being indicated by the claims.

LIST OF REFERENCE NUMBERS

1

groove

2

groove

3

casing

4

Rack, axially movable

5

intermediate element

6

intermediate element

7

intermediate element

8th

Contact point with housing

9

Contact point with rack

10

insert sleeve

11

tie rod

12

torque sensor

13

control unit

14

pinion

15

belt

16

Ball Screw

17

servomotor

18

steering column

Claims (10)

A steering system for steering a wheel of a vehicle, comprising: a tie rod (11) for deflecting the wheel, a rack (4), which leads by an axial displacement to control the tie rod (11), and a housing (3), wherein the rack ( 4) is at least partially disposed within the housing, characterized in that the rack (4) has a convex or concave cross-sectional portion, wherein the housing (3) comprises a complementary concave or convex shape, whereby a positive connection results in the realization of an anti-rotation , Steering system after Claim 1 , characterized in that between the housing (3) and rack (4) has an intermediate element (6) to ensure a low-friction and low-wear Sliding friction, a high accuracy of fit and a Spielarmut or freedom from play is arranged Steering system according to one of the preceding claims, characterized in that between the housing (3) and intermediate element (6) an insert bushing (10) is present, which is connected to the housing (3). Steering system according to one of the preceding claims, characterized in that the intermediate element (6, 7) is formed integrally with the housing (3) or integrally with the insert bush (10) or integrally with the rack (4). Steering system according to one of the preceding claims, characterized in that the intermediate element (6) between the housing (3) and rack (4) is injected or inserted. Steering system according to one of the preceding claims, characterized in that the intermediate element (6) in the radial and / or in the axial direction has a waveform, in particular a sinusoidal waveform. Steering system according to one of the preceding claims, characterized in that the steering system is suitable for high-autonomous driving. Steering system according to one or more of the preceding claims, characterized in that the steering system is suitable for steer-by-wire and / or wherein the steering system is suitable as a rear axle steering. Steering system according to one of the preceding claims, characterized in that a metallic protrusion of the housing (3) or the rack (4) in a matching metallic recess of the rack (4) or the housing (3) protrudes. Vehicle, characterized in that the vehicle comprises a steering system according to one of the preceding claims.

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