WO2024041693A1

WO2024041693A1 - Length-adjustable operating unit and steer-by-wire system

Info

Publication number: WO2024041693A1
Application number: PCT/DE2023/100566
Authority: WO
Inventors: Sebastian Müller; Benjamin Severin; Joseph GISSLER
Original assignee: Schaeffler Technologies AG & Co. KG
Priority date: 2022-08-22
Filing date: 2023-08-01
Publication date: 2024-02-29
Also published as: DE102022121115A1

Abstract

The invention relates to a length-adjustable operating unit (1) for influencing a driving direction of a motor vehicle (2) by a user, in particular for use in a steer-by-wire system (3), comprising an actuatable telescopic pull-out system (4) having an inner casing tube (5), a central casing tube (7), which is arranged coaxially to the inner casing tube (5), and the central casing tube (7) at least partially surrounds the inner casing tube (5), and an outer casing tube (8), which is arranged coaxially to the central casing tube (7), and the outer casing tube (8) at least partially surrounds the central casing tube (7), wherein the central casing tube (7) is able to be offset axially relative to the outer casing tube (8), wherein the inner casing tube (5) is connected to an energy absorption element (9), which is arranged inside the central casing tube (7), such that, in the presence of a predefined triggering force acting in the retraction direction of the telescopic pull-out system (4), the inner casing tube (5) is offset with respect to the energy absorption element (9), which deforms under the action of force.

Description

Length-adjustable control unit and steer-by-wire system

The present invention relates to a length-adjustable operating unit for influencing a driving direction of a motor vehicle by a user, in particular for use in a steer-by-wire system, comprising an actuable telescopic extension with an inner casing tube, a middle casing tube, which is coaxial with the inner casing tube is arranged and the middle jacket tube surrounds the inner jacket tube at least in sections, an outer jacket tube which is arranged coaxially to the middle jacket tube, and the outer jacket tube surrounds the middle jacket tube at least in sections, the middle jacket tube being axially displaceable relative to the outer jacket tube. The invention further relates to a steer-by-wire system.

Electric steering devices are used - among other things in motor vehicles - to receive a driver's direction request and to convert it into corresponding movements of one or more wheels. Compared to purely mechanical steering devices, a distinction is made between electrical steering devices between electrically assisted steering devices and fully electric steering devices, so-called “steer-by-wire” steering devices. These steer-by-wire steering devices in particular have the advantage that the control unit can be positioned relatively freely within the vehicle independently of mechanical connection components, which, in addition to cost savings when distinguishing between, for example, right-hand and left-hand drive vehicles, also improves accident behavior due to the absence a steering column. Furthermore, the control unit can be brought into a stowage position, which is also used, for example, with fully automatic steering.

A steer-by-wire steering system in the context of the present invention is to be understood as meaning a steering system which essentially consists of a so-called hand wheel actuator (HWA), for example the actuator system around the commanding vehicle steering wheel, and a road wheel actuator ( RWA), i.e. the one on the actuators connected to the steering mechanism connected to the vehicle wheels. The steering signal is transmitted from the HWA to the RWA via wire.

Such systems are basically known from the prior art. Thus, DE 102015224602 A1 discloses an adjustable steering column for a steer-by-wire steering device of a motor vehicle, comprising an actuating unit which includes a steering spindle rotatably mounted in a casing unit about a longitudinal axis, the casing unit having a first casing tube in which at least one second casing tube is arranged in a rotationally fixed manner with respect to the longitudinal axis and is mounted in a telescopic, axially displaceable manner, with an actuator being connected to the first and second casing tubes, of which the second casing tube can be axially retracted and extended relative to the first casing tube, and which comprises a spindle drive with a parallel to the longitudinal axis, which can be driven in rotation by an electric servomotor and which is supported on a casing tube and which is screwed into a spindle nut which is attached to the other casing tube in a rotationally fixed manner, the threaded spindle extending within the first casing tube, and the spindle nut on the second casing pipe is attached

DE 102018 212 696 B3 also discloses an adjustment drive for a motor-adjustable steering column for a motor vehicle, comprising a motor drive unit and an external threaded spindle, which has an external thread and a coaxial internal thread, into which an internal threaded spindle engages, the external -Threaded spindle and the internal threaded spindle can be driven by the drive unit to rotate relative to one another about an axis. In order to provide an adjustment drive that requires a lower drive torque and offers an optimized free adjustment path, DE 102018 212 696 B3 proposes that the external threaded spindle engages with its external thread in a drive nut, the drive nut or the internally threaded spindle can be driven in rotation by the drive unit and is supported in the direction of the axis relative to the drive unit.

With regard to the further development towards autonomous driving, we would like to give the driver of the vehicle the opportunity to use the steering wheel autonomously During ferry operations, the vehicle can be retracted almost completely towards the dashboard in order to achieve an improved comfort level without a steering wheel that may be perceived as disturbing, which also allows completely new design concepts for the passenger cell.

With such new designs of the passenger cell in autonomously driving motor vehicles, there are often special requirements for the steering wheel to be retracted, in particular with regard to the required travel distance, which is usually significantly greater than the travel distance for an extendable steering column in a non-autonomous driving automobile.

Implementing larger travel distances over longer spindles using the approaches known from the prior art is critical in terms of installation space and stability. For example, in conventional concepts the spindle would have to be longer than the steering column, which would lead to a collision with the steering wheel when retracting. In addition, passive vehicle safety is significantly worsened because there is a penetrator in the driver's direction.

In the case of the spindle drives mentioned at the beginning, the spindle nut on the spindle drive is usually designed to be self-locking, which means that in the event of an accident, an impact force on the steering wheel is supported by the self-locking mechanism, which increases the risk of injury. By interposing a crash element between the slide and the spindle nut, the risk of injury to the driver is reduced in the event of an accident by allowing the steering wheel to give way or retreat when force is applied.

Such crash elements are used in safety steering columns of the type outlined above to enable the steering wheel (or the casing tube connected to the steering wheel) to be pushed away over a distance of 80-120mm in the event of an accident. As a result, when the steering wheel is extended, in the event of a crash, for example, the impact of the driver's head is further mitigated and injuries are minimized. Crash elements based on bending strips are widely used, which absorb pre-adjustable displacement forces and curves of 1 -5 kN when bending and bending back a guided sheet metal strip. An example of such crash elements can be found in DE102020209038A1. Plastic deformation plays an important role here, while elasticity, like a spring, is disruptive because it does not destroy energy (but reflects it back).

An unavoidable disadvantage of the bending strips is that they always have to be "grasped" or "enclosed" so that the bending occurs with a defined small radius or curvature, whereby the curvature determines the force or the energy that can be converted into plastic deformation.

Crash elements are also known from the prior art, in which a rider is pushed over a strip and stretches it or flanges it at the edge, such as in US2020189648. Crash elements such as in CN1 10155152B, which are based on the expansion of an elongated hole by a bolt, are also known. Crash elements based on conical cross-sectional taper are also known, as is also disclosed in WO18210874.

Central, coaxial crash elements are also known, which have the advantage of not generating any transverse forces or tilting moments. This makes adjacent components much easier to implement (smaller, weaker, lighter, guideless, smooth). The principles used here are friction (often tolerance-critical) or deformation or continuous tearing, as shown, for example, in DE102016121876A1.

For many of the crash elements mentioned, the force level and a force progression can be set in advance, e.g. through the width or thickness progression of components when bending or tearing.

The object of the present invention is to provide a length-adjustable operating unit for influencing the direction of travel of a motor vehicle by a user, in particular for use in a steer-by-wire system, that solves the problems known from the prior art avoided or at least reduced. It is also the object of the invention to realize a length-adjustable operating unit which is particularly compact in construction and inexpensive to manufacture.

This object is achieved by a length-adjustable operating unit for influencing a driving direction of a motor vehicle by a user, in particular for use in a steer-by-wire system, comprising an actuable telescopic extension with an inner jacket tube, a middle jacket tube, which is coaxial to the inner Jacket tube is arranged and the middle jacket tube surrounds the inner jacket tube at least in sections, an outer jacket tube which is arranged coaxially to the middle jacket tube, and the outer jacket tube surrounds the middle jacket tube at least in sections, the middle jacket tube being axially displaceable relative to the outer jacket tube, wherein the inner casing tube is connected to an energy absorption element which is arranged within the central casing tube, so that when a predefined trigger force acting in the retraction direction of the telescopic extension is present, the inner casing tube is offset against the energy absorption element, which deforms under the force.

This achieves the advantage that the energy absorption element is effectively space-neutral and can therefore be integrated very compactly into a length-adjustable operating unit. The compact structure and the use of only a very small number of components also result in the control unit being manufactured cost-effectively.

The central arrangement of the energy absorption element also results in short tolerance chains. In the configurations described later as particularly preferred embodiments, there are no lever arms in the force flow due to a direct introduction of force from the inner casing tube into the energy absorption element.

According to the invention, at least one energy absorption element is provided within the central casing tube. It is of course also possible that several energy absorption elements are present in a series connection and/or parallel connection in order to increase the energy absorption capacity. It is advantageous that the majority of energy absorption elements are essentially identical, which in particular brings with it cost advantages due to increased uniformity.

In principle, the energy absorption element can have any spatial shape that can be positioned within the central casing tube and can be deformed, in particular compressed, in the axial direction by the inner casing tube in the event of a crash. It is advantageous if the outer contour of the energy absorption element rests at least in sections on the inner lateral surface of the middle jacket tube, so that it is centered in the middle jacket tube.

According to an advantageous embodiment of the invention, it can be provided that the energy absorption element is designed as a hollow cylindrical body which is arranged within the central casing tube and is axially fixed in position on one side in the retraction direction of the telescopic extension, the inner casing tube being arranged on the front side of the energy absorption element. In this way, a particularly lightweight energy absorption element can be realized.

In this context, it is particularly preferred that the energy absorption element designed as a hollow cylindrical body is made of a plastic, particularly preferably of a glass fiber reinforced plastic. It may be further preferred that the energy absorption member is formed of a porous material based on plastic or metal, which can further improve the energy absorption capabilities.

According to a further preferred development of the invention, it can also be provided that the energy absorption element is arranged in one piece on the middle jacket tube and extends at least in sections radially inwards with a contact section into the middle jacket tube, the inner jacket tube resting on the contact section. This can be achieved that the energy absorption element can be formed in or on the middle casing tube in a manufacturing process, for example punching.

Furthermore, according to a likewise advantageous embodiment of the invention, it can be provided that the inner jacket tube and the middle jacket tube have a polygonal, in particular octagonal, cross-sectional contour that deviates from the circular shape. The advantageous effect of this configuration is that a relative movement of the casing tubes in the circumferential direction is prevented.

According to a further particularly preferred embodiment of the invention, it can be provided that the inner casing tube and the middle casing tube are axially fixed to one another via at least one triggering means, with the triggering means being released, deformed and/or destroyed in the presence of a predefined triggering force acting in the retraction direction of the telescopic extension is so that the inner casing tube is offset against the energy absorption element, which deforms under the force. This makes it possible, in particular, to achieve the effect that the triggering time can be controlled or adjusted very precisely.

Furthermore, the invention can also be further developed in such a way that the operating unit comprises a steering shaft which passes through the inner casing tube and the middle casing tube coaxially, the steering shaft being rotatably coupled to a steering means and rotatable relative to the inner casing tube and the middle casing tube by means of a rolling bearing arrangement is stored. The advantage of this design is that a multifunctional assembly can be formed that combines the bearing and a crash element in a very compact manner, which offers advantages in terms of manufacturing and assembly technology.

In a likewise preferred embodiment variant of the invention, it can also be provided that the inner casing tube has a first cylindrical ring-shaped bearing seat for a first rolling bearing of the rolling bearing arrangement and / or the middle casing tube has a second cylindrical ring-shaped bearing seat for a second rolling bearing of the rolling bearing arrangement. In this context, it is particularly preferred that the first bearing seat is made in one piece, in particular monolithically, is formed with the inner jacket tube and / or the second bearing seat is formed in one piece, in particular monolithically, with the middle jacket tube, which means, for example, that there is no need to weld a separate bearing seat.

It can also be advantageous to further develop the invention in such a way that the first rolling bearing is configured as a fixed bearing and the second rolling bearing as a floating bearing, so that, for example, thermal expansion can be compensated for.

According to a further preferred embodiment of the subject matter of the invention, it can be provided that the second roller bearing is subjected to an axial force via a preloading means, the preloading means being releasably axially supported on the steering shaft, so that when a predefined triggering force is present, acting in the retraction direction of the telescopic extension Biasing means is offset relative to the second rolling bearing. This can ensure that in a crash scenario the preloading means releases the preload on the second rolling bearing and the steering shaft can thereby slide axially through the second rolling bearing.

The object of the invention is further achieved by a steer-by-wire system for influencing the direction of travel of a motor vehicle by a user, comprising a length-adjustable operating unit according to one of claims 1 -9.

The invention will be explained in more detail below using figures without restricting the general idea of the invention.

It shows:

1 shows a motor vehicle with a steer-by-wire system in a schematic block diagram,

Figure 2 shows a length-adjustable control unit of a steer-by-wire system in a perspective view, 3 shows a telescopic extension of a first embodiment of a length-adjustable operating unit in an axial sectional view and an exploded view,

4 shows a telescopic extension of a second embodiment of a length-adjustable operating unit in an axial sectional view and an exploded view,

5 shows a telescopic extension of a third embodiment of a length-adjustable operating unit in an axial sectional view and an exploded view,

6 shows an energy absorption element of a length-adjustable operating unit in an operating position before and after a crash event in an axial sectional view,

Figure 7 shows a detailed view of the second rolling bearing and a preloading means in an axial sectional view.

1 shows a length-adjustable operating unit 1 for influencing the direction of travel of a motor vehicle 2 by a user, within a steer-by-wire system 3. Electrical signals are sent from the operating unit 1 to an RWA 19 (road wheel actuator), which translates the steering movements on the control unit into an adjusting movement of the vehicle wheels.

The basic structure of the length-adjustable operating unit 1 can be seen in FIG.

The length-adjustable operating unit 1 comprises an actuable telescopic extension 4 with an inner casing tube 5 and a central casing tube 7, which is arranged coaxially to the inner casing tube 5. The middle casing tube 7 surrounds the inner casing tube 5 at least in sections can also be clearly seen in the axial sectional views of Figures 3-6.

The middle jacket tube 7 cannot be seen in the illustration in FIG. 2 because it is located inside the outer jacket tube 8.

The telescopic extension 4 also has an outer jacket tube 8, which is arranged coaxially to the middle jacket tube 7. The outer jacket tube 8 encompasses the middle jacket tube 7 at least in sections, the middle jacket tube 7 being axially displaceable relative to the outer jacket tube 8, so that the length-adjustable operating unit 1 can be telescoped.

As can be seen from Figures 3-6, the inner jacket tube 5 is connected to an energy absorption element 9, which is arranged within the middle jacket tube 7, so that when there is a predefined triggering force acting in the retraction direction of the telescopic extension 4, the inner jacket tube 5 counteracts the energy absorption element 9 is offset, which deforms under the force. This can be understood particularly well with reference to FIG. 6.

3, the energy absorption element 9 is designed as a hollow cylindrical body, which is arranged within the central casing tube 7 and is axially fixed in position on one side in the retraction direction of the telescopic extension 4, the inner casing tube 5 being arranged on the front side of the energy absorption element 9.

Figures 4-5 show embodiments in which the energy absorption element 9 is arranged in one piece on the middle jacket tube 7 and extends at least in sections radially inwards with a contact section 10 into the jacket tube 7, the inner jacket tube 5 resting on the contact section 10. 4 shows an embodiment in which the energy absorption element 9 is designed as a tab which is formed in one piece with the central casing tube 7 and extends in the axial direction. Figure 5 shows a variant in which the energy absorption element 9 was formed by a strip-like caulking extending in the axial direction.

As shown in Figures 2-5, the inner jacket tube 5 and the middle jacket tube 7 have a polygonal, in particular octagonal, cross-sectional contour that deviates from the circular shape.

As can also be clearly seen from Figures 3-6, the inner casing tube 5 and the middle casing tube 7 are axially fixed to one another via at least one triggering means 18, whereby in the presence of a predefined triggering force acting in the retraction direction of the telescopic extension 4, the triggering means 18 is released and deformed and/or destroyed, so that the inner casing tube 5 is offset against the energy absorption element 9, which deforms under the force.

6 shows an embodiment in which the operating unit 1 comprises a steering shaft 11, which coaxially passes through the inner jacket tube 5 and the middle jacket tube 7, the steering shaft 11 being rotatably coupled to a steering means 6 and rotatable relative to it by means of a rolling bearing arrangement 12 the inner jacket tube 5 and the middle jacket tube 7 is stored. Here, the inner casing tube 5 has a first cylindrical ring-shaped bearing seat 13 for a first rolling bearing 14 of the rolling bearing arrangement 12 and the middle casing tube 7 has a second cylindrical ring-shaped bearing seat 15 for a second rolling bearing 16 of the rolling bearing arrangement 12. In the configuration shown, the first rolling bearing 14 is as a fixed bearing and the second rolling bearing 16 is designed as a floating bearing.

Based on Figures 6-7 it can be understood that the second rolling bearing 16 is subjected to an axial force via a preloading means 17, the preloading means 17 being releasably axially supported on the steering shaft 11, so that when there is a predefined, in the retraction direction of the telescopic extension 4 acting triggering force, the biasing means 17 is offset relative to the second roller bearing 16. The invention is not limited to the embodiments shown in the figures. The foregoing description is therefore not to be viewed as limiting but rather as illustrative. The following patent claims are to be understood as meaning that a stated feature is present in at least one embodiment of the invention. This does not exclude the presence of other features. If the patent claims and the above description define 'first' and 'second' features, this designation serves to distinguish two similar features without establishing a ranking.

Reference character list

1 control unit

2 motor vehicle

3 Steer-By-Wire system

4 telescopic extensions

5 inner casing tube

6 steering means

7 middle casing pipe

8 outer casing tube

9 energy absorption element

10 investment section

11 steering shaft

12 rolling bearing arrangement

13 first bearing seat

14 first rolling bearing

15 second bearing seat

16 second rolling bearing

17 prestressing means

18 triggering agents

19 RWA

Claims

Claims Length-adjustable control unit (1) for influencing the direction of travel of a motor vehicle

(2) by a user, in particular for use in a steer-by-wire system (3), comprising an actuable telescopic extension (4) with an inner jacket tube (5), a middle jacket tube (7), which is coaxial with the inner Jacket tube (5) is arranged and the middle jacket tube (7) surrounds the inner jacket tube (5) at least in sections, an outer jacket tube (8) which is coaxial with the middle jacket tube

(7) is arranged, and the outer jacket tube (8) surrounds the middle jacket tube (7) at least in sections, the middle jacket tube (7) being axially displaceable relative to the outer jacket tube (8), characterized in that the inner jacket tube (5) is connected to an energy absorption element (9), which is arranged within the central casing tube (7), so that when a predefined trigger force acting in the retraction direction of the telescopic extension (4) is present, the inner casing tube (5) is offset against the energy absorption element (9). , which deforms under the force. Length-adjustable operating unit (1) according to claim 1, characterized in that the energy absorption element (9) is designed as a hollow cylindrical body which is arranged within the central casing tube (7) and is axially fixed in position on one side in the retraction direction of the telescopic extension (4), whereby the inner casing tube (5) is arranged on the front side of the energy absorption element (9).

3. Length-adjustable operating unit (1) according to claim 1 or 2, characterized in that the energy absorption element (9) is arranged in one piece on the central casing tube (7) and extends at least in sections radially inwards with a contact section (10) in the casing tube (7 ) extends into it, with the inner casing tube (5) resting on the contact section (10).

4. Length-adjustable operating unit (1) according to one of the preceding claims, characterized in that the inner jacket tube (5) and the middle jacket tube (7) have a polygonal, in particular octagonal, cross-sectional contour that deviates from the circular shape.

5. Length-adjustable operating unit (1) according to one of the preceding claims, characterized in that the inner jacket tube (5) and the middle jacket tube (7) are axially fixed to one another via at least one triggering means (18), whereby in the presence of a predefined, in the retraction direction of the Telescopic extension (4) acting triggering force, the triggering means (18) is released, deformed and / or destroyed, so that the inner casing tube (5) is offset against the energy absorption element (9), which deforms under the force.

6. Length-adjustable operating unit (1) according to one of the preceding claims, characterized in that the operating unit (1) comprises a steering shaft (11) which passes through the inner casing tube (5) and the middle casing tube (7) coaxially, the steering shaft ( 11) can be coupled in a rotationally fixed manner to a steering means (6) and by means of a Rolling bearing arrangement (12) is rotatably mounted relative to the inner jacket tube (5) and the middle jacket tube (7).

7. Length-adjustable operating unit (1) according to claim 6, characterized in that the inner jacket tube (5) has a first cylindrical ring-shaped bearing seat (13) for a first rolling bearing (14) of the rolling bearing arrangement (12) and / or the middle jacket tube (7) has a second cylindrical ring-shaped bearing seat (15) for a second rolling bearing (16) of the rolling bearing arrangement (12).

8. Length-adjustable operating unit (1) according to one of the preceding claims 6-7, characterized in that the first rolling bearing (14) is configured as a fixed bearing and the second rolling bearing (16) is configured as a floating bearing.

9. Length-adjustable operating unit (1) according to one of the preceding claims 6-8, characterized in that the second rolling bearing (16) is subjected to an axial force via a preloading means (17), the preloading means (17) being located on the steering shaft (11 ) is releasably supported axially, so that when there is a predefined triggering force acting in the retraction direction of the telescopic extension (4), the preloading means (17) is offset relative to the second roller bearing (16).

10. Steer-by-wire system (3) for influencing a driving direction of a motor vehicle (2) by a user, comprising a length-adjustable operating unit (1) according to one of the preceding claims.