EP4077101A1

EP4077101A1 - Steering wheel

Info

Publication number: EP4077101A1
Application number: EP20838419.8A
Authority: EP
Inventors: Fabián Conde Bouza; Jorge Ollero Ollero; Xabier LEMA MARTÍNEZ
Original assignee: Dalphi Metal Espana SA
Current assignee: Dalphi Metal Espana SA
Priority date: 2019-12-20
Filing date: 2020-12-17
Publication date: 2022-10-26
Also published as: WO2021123001A1; DE102019135456A1; US20230039647A1

Abstract

The invention relates to improving the structure of a steering wheel. According to the invention, a steering wheel has a monolithic steering wheel main body which comprises a central region for fastening the steering wheel to a steering mechanism, a steering wheel rim and at least one spoke, the first spoke end adjoining the central region and the second spoke end adjoining the steering wheel rim. In the region of the first spoke end (6) a projection (8) is formed which limits tilting of the spoke (5) towards the central region (3) to a predetermined extent.

Description

steering wheel

The invention relates to a steering wheel with a monolithic steering wheel body which has a central area for fastening the steering wheel to a steering mechanism, a steering wheel rim and at least one spoke, the first spoke end of which adjoins the central area and the second spoke end of the steering wheel rim.

Modern steering wheels for passenger vehicles contain a steering wheel base body (also referred to as a steering wheel skeleton), which is manufactured in one piece from magnesium or aluminum in a die-casting process. They are arranged in the vehicle at an angle to the horizontal.

In connection with the steering wheels of motor vehicles, there are various tests that the newly designed steering wheels must pass. On the one hand, fatigue defects are tested. It is desirable here for the steering wheels, in particular the steering wheel skeletons, to withstand high continuous loads.

In addition, it is necessary that the steering wheels, in particular the steering wheel skeletons, have an adapted bending stiffness, since in the crash test the steering wheel rim supported by the spokes may only offer a standardized resistance to body contact with a dummy.

To achieve this, the spoke must often be designed so that it can bend or kink. However, the spoke must not break, particularly in the area where the spokes connect to the steering wheel rim.

When designing steering wheels whose steering wheel body (also known as steering wheel skeleton) is manufactured in an injection molding process, it can prove difficult to design the spokes in such a way that they meet these requirements, especially if switch elements are still to be attached and certain requirements are placed on the Appearance are to be met.

The invention is therefore based on the object of creating an improved steering wheel that meets the requirements. For a steering wheel of the type mentioned at the outset, this object is achieved according to the invention in that a projection is formed in the area of the first spoke end which limits tilting of the spoke towards the central area to a predetermined amount.

This can prevent the spoke from bending so far in the event of an impact on the steering wheel rim that it tears off on the steering wheel rim.

According to a further embodiment, it is preferred that the projection is formed on the spoke on its side facing the central area. As a result, the projection can be arranged at a point on the steering wheel base body at which other steering wheel components are not hindered.

According to a further embodiment, it is preferred that a stop, in particular in the form of a coupling device for an airbag module, is formed in the area of the first spoke end on the central area, such that there is a gap between the projection and the stop.

This means that only minor changes to the central area are required. In addition, the path by which the spoke is allowed to move in the event of a crash can be determined in a simple manner by defining the gap width.

According to a further embodiment it is preferred that the projection extends transversely to the main direction of construction of the first spoke section only over less than a third of the width of the first spoke section and is preferably arranged in the middle. As a result, the desired effect can be achieved in a particularly material-saving manner. According to a further embodiment, it is preferred that the spoke has a first spoke section, the main construction direction of the first spoke section and the main construction plane of the central area enclosing an angle β which is between 40 ° and 80 °, preferably between 50 ° and 75 °.

As a result, the attachment area of the spoke at the central area acts like a hinge which, in the event of a crash, allows the spoke to tilt or fold at the attachment area when a force is applied, but prevents it from being sheared off or broken off. According to a further embodiment it is preferred that the spoke has a first spoke section and a second spoke section, wherein the main direction of construction of the first spoke section and the main direction of construction of the second spoke section enclose an angle α of between 30 ° and 70 °, preferably between 40 ° and 60 ° ° is.

As a result, the transition area of the spoke between the first spoke section and a second spoke section acts like a hinge which, in the event of a crash, causes the spoke or the two spoke areas to fold with respect to one another allowed, so that the spoke can yield when a force is applied to the steering wheel rim, but shearing or breaking off of the steering wheel rim is prevented.

According to a further embodiment, it is preferred that the spoke is essentially S-shaped along its main structural directions, i.e. its curvature from its point of attachment on the central area to its point of attachment on the steering wheel rim several times, in particular from an anti-clockwise curvature to a clockwise curvature and again changes to a counterclockwise curve.

This allows the spoke to yield when a force is exerted on the steering wheel rim, but it prevents it from shearing off or breaking off from the steering wheel rim.

According to a further embodiment, it is preferred that in the transition area from the first spoke section to the second spoke section at least one reinforcement structure is formed which extends along the main structural directions of the spoke on its side facing the central area.

Since the described design of the spoke causes the outer sides of the two spoke sections to fold towards each other when a force is applied to the steering wheel rim, with the transition area between the first spoke section and a second spoke section acting like a hinge, tensile stresses arise on the inside of the spoke at this transition area. By providing the reinforcement structure, the rigidity and thus the bending behavior or the resistance to the action of force on the steering wheel rim can be adjusted.

According to a further embodiment, it is preferred that at least one receiving point or coupling device for operating elements is formed on the second spoke section.

This enables a reliable connection of the necessary operating elements to the steering wheel base body.

According to a further embodiment, it is preferred that at least one recess is provided on the second spoke section.

This enables weight and material savings on the steering wheel base body. The bending behavior of the spoke can also be adjusted.

According to a further embodiment it is preferred that at least two spokes are provided, these being connected to the steering wheel rim, preferably at 90 ° and at 270 °, when the steering wheel is installed, at a steering angle of 0 °. A wider spoke at 180 °, i.e. at the bottom, is conceivable.

This enables a secure connection of the central area to the steering wheel rim. According to a further embodiment, it is preferred that the steering wheel base body has a foam coating and is optionally provided with a casing (preferably made of leather and / or wood) at least of the steering wheel rim and / or (parts of) the spoke, whereby preferably operating elements, a steering wheel heater and / or sensor device are provided. An airbag module is also preferably provided.

As a result, a steering wheel can be created that meets modern requirements for user-friendliness and safety.

Further features are the subject of the subclaims.

In the following, further details and features of the invention are explained in more detail using exemplary embodiments with reference to the drawing. These show: FIG. 1 a schematic partial view (from below) of an embodiment of the steering wheel according to the invention;

FIG. 2 shows a perspective partial view of the embodiment of the steering wheel base body of the steering wheel according to the invention;

FIG. 3 shows a partial side view of the embodiment of the steering wheel according to the invention; and

FIG. 4 shows a schematic view of the steering wheel base body of the steering wheel according to the invention during an impact test.

In Figure 1, an embodiment of the steering wheel according to the invention is shown schematically. As shown, the steering wheel base body 1, which is described in more detail below, is provided with a foam coating 17 in the area of its main spokes (hereinafter: spoke) 5, its optional auxiliary spokes 5a and the steering wheel rim. Their surface can also be completely or partially provided with a casing, preferably made of leather and / or wood.

The steering wheel 1 can be equipped with various operating elements 19 on the spokes. A steering wheel heater and / or sensor device can also be provided on the steering wheel rim 4. Finally, an airbag module 18 can complete the steering wheel 1. As shown in Figure 3, the steering wheel body 2 is monolithically made as a light metal casting, preferably made of aluminum or magnesium alloy, and has a hub 20 in its center, via which the steering wheel 1 can be attached to a handlebar or a steering mechanism.

The imaginary steering axis L extends through the center of the hub. A main structural level Ez of the central area 3 of the steering wheel base body 2 extends perpendicular to it. In the main structural level Ez, at least one, preferably 2, and possibly also three or four spokes 5 close to the side of the central area 3 who wear the steering wheel rim 4. In the embodiment shown, the spokes 5 are essentially S-shaped, that is, they have a curvature that changes several times from their attachment area 6a on the central area 3 to their attachment point 7a on the steering wheel rim 4, which in particular changes from a counterclockwise curvature to a curvature in the Changes clockwise and back to a counter-clockwise curve.

As a result, the spoke 5, as explained in more detail below with reference to FIG. 4, can yield when a force is exerted on the steering wheel rim 4, but a shearing off or breaking off of the steering wheel rim 4 is prevented.

In detail, it is provided that the spoke 5 has a first spoke section 11, the main structural direction H1 of the first spoke section 11 and the main structural plane Ez of the central area 3 enclosing an angle β of between 40 ° and 80 °, preferably between 50 ° and 75 ° , is. In the embodiment shown, the angle ß = 70 °.

It is further provided that the spoke has a second spoke section 12 following the first spoke section 11, the main direction H1 of the first spoke section 11 and the main direction H2 of the second spoke section 12 enclosing an angle a of between 30 ° and 70 °, preferably between 40 ° and 60 °. In the embodiment shown, the angle a = 50 °.

As shown in FIGS. 1 to 4, a projection 8 is formed in the area 6 of the first spoke end, which protrudes approximately in the middle on the inside of the spoke 5. This projection is preferably designed like an anvil. Opposite it, a stop 9 is also formed in the area 6 of the first spoke end on the central area 3. A gap 13 is present between the projection 8 formed on the spoke 5 and the stop 9. This can be wedge-shaped or with parallel gap walls. The width of the gap 13 between the projection 8 and the stop 9 determines the amount by which the first spoke section 11 can tilt around its attachment area 6a towards the central area 3 when a compressive force is applied to the spoke 5 (from the steering wheel rim 4) .

The rear side of a coupling device 10 for an airbag module, in particular a latching hook provided on the central area, can preferably function or be designed as a stop 9.

As can best be seen in FIGS. 2 and 3, at least one reinforcement structure 14 is formed in the transition area from the first spoke section 11 to the second spoke section 12, which extends along the main structural directions H1, H2 extends the spoke 5 on its (inner) side facing the central area 3. The number (three in the embodiment shown) and the respective width and height of the reinforcement structures 14 provided can be used to set the rigidity and thus the bending behavior or the resistance to the action of force on the steering wheel rim 4.

To further explain the invention, FIG. 4 shows an impact test in which a dummy body D strikes the steering wheel rim 4 of a steering wheel base body 2 of the steering wheel 1 according to the invention.

The illustrated impact of the dummy body D causes a strong force to be exerted on the steering wheel rim 4, as a result of which it is deformed predominantly in the direction of the steering axis L. At the attachment point 7a of the upper spoke section 12, this force hits the spoke 5. In a conventional spoke, a break at one of the attachment points 6a or 7a is at least theoretically conceivable if the spoke 5 are excessively bent.

By providing a bending control member 8 according to the invention, namely the projection, the spoke breakage can be prevented in the critical regions. By restricting the bending of the spoke at its attachment points 6a and 7a, stresses that exceed the yield point of the material can be avoided on the outer regions of the flexurally loaded attachment points 6a and 7a of the spoke 5.

To absorb the acting force, a controlled bending of the spoke 5 is brought about at the transition area from the first spoke section 11 to the second spoke section 12. Due to the described design of the spoke 5, when a force is applied to the steering wheel rim 4, the outsides of the two spoke sections 11, 12 fold towards each other, the transition area between the first spoke section 11 and a second spoke section 12 acting like a hinge. The angle a between the main directions H1 and H2 of the spoke also contributes to this.

The reinforcement structures 14 are provided in order to adjust the bending behavior due to the tensile stresses that arise at this transition area. List of reference symbols

1 steering wheel

2 steering wheel bodies

3 Central area of the steering wheel body

4 steering wheel rim

5 spoke

6 First end of the spoke

7 Second end of the spoke

8 head start

9 stop

10 coupling device

11 First spoke section

12 Second spoke section

13 gap

14 Reinforcement structure

15 Coupling point / receptacle for control elements

16 recess

17 Foam / sheathing

18 airbag module

19 Control element / switch

20 hub

D dummy body

L steering axle

B Width of the spoke

Ez main construction plane of central area H1 main construction direction H1 of first spoke section 11 H2 main construction direction H2 of second spoke section 12

V direction of deformation

Claims

1. Steering wheel with a monolithic steering wheel body (2) which has a central area (3) for fastening the steering wheel (1) to a steering mechanism, a steering wheel rim (4) and at least one spoke (5), the first spoke end (6) of which to the Central area (3) and its second spoke end (7) adjoins the steering wheel rim (4), characterized in that a projection (8) is formed in the area of the first spoke end (6), which allows the spoke (5) to tilt towards the central area (3) limited to a predetermined level.

2. Steering wheel according to claim 1, characterized in that the projection (8) is formed on the spoke (5) on its side facing the central region (3).

3. Steering wheel according to claim 1 or 2, characterized in that a stop (9), in particular in the form of a coupling device (10) for an airbag module, is formed in the region of the first spoke end (6) on the central region (3), such that that there is a gap (13) between the projection (8) and the stop (9).

4. Steering wheel according to at least one of claims 1 to 3, characterized in that the projection (8) extends transversely to the main direction (H1) of the first spoke section (11) only over less than a third of the width (B) of the first spoke section (11 ) extends and, preferably arranged centrally.

5. Steering wheel according to at least one of claims 1 to 4, characterized in that the spoke (5) has a first spoke section (11), the main construction direction (H1) of the first spoke section (11) and the main construction plane (Ez) of the central area ( 3) enclose an angle (β) which is between 40 ° and 80 °, preferably between 50 ° and 75 °.

6. Steering wheel according to at least one of claims 1 to 5, characterized in that the spoke (5) has a first spoke section (11) and a second spoke section (12), wherein the main direction (H1) of the first spoke section (11) and the Main construction direction (H2) of the second spoke section (12) enclose an angle (a) which is between 30 ° and 70 °, preferably between 40 ° and 60 °.

7. Steering wheel according to at least one of claims 1 to 6, characterized in that in the transition area from the first spoke section (11) to the second spoke section (12) at least one reinforcement structure (14) is formed which extends along the main structural directions (H1, H2) extends the spoke (5) on its side facing the central area (3).

8. Steering wheel according to at least one of claims 1 to 7, characterized in that at least one receiving point or coupling device (15) for operating elements is formed on the second spoke section (12) and / or that at least one on the second spoke section (12) Recess (16) is provided.

9. Steering wheel according to at least one of claims 1 to 8, characterized in that at least two spokes (5) are provided, these in the installed state of the steering wheel at 0 ° steering angle with the steering wheel rim (4) preferably at 90 ° and at 270 ° are connected.

10. Steering wheel according to at least one of claims 1 to 9, characterized in that the steering wheel base body (2) has a foam coating and is optionally provided with a casing (leather / wood) of at least the steering wheel rim (4) and / or the spoke (5), wherein control elements, a steering wheel heater and / or sensor device are preferably provided.