steering wheel

Abstract

Steering wheel (1) with a steering wheel rim (4) comprising a rim skeleton (5) and a rim shell (6) at least partially enclosing the rim skeleton (5), wherein the rim skeleton (5) has a cavity (7) which is at least partially filled with a medium, and the cavity (7) is bounded by a wall surface (9) of the rim skeleton (5) and by a wall surface (10) of the rim shell (6) which is made of an elastically deformable material, wherein the medium arranged in the cavity (7) consists of a plurality of loose particles (8), characterized in that at least two radially extending partition walls are provided in the cavity (7) so that the particles (8) can be arranged in sectors.

Description

[0001] The invention relates to a steering wheel with a steering wheel rim comprising a rim skeleton and a rim shell that at least partially encloses the rim skeleton, wherein the rim skeleton has a cavity which is at least partially filled with a medium. Furthermore, the cavity is bounded by a wall surface of the rim skeleton and by a wall surface of the rim shell, which is made of an elastically deformable material, wherein the medium arranged in the cavity consists of a plurality of loose particles.

[0002] In many vehicles, high-frequency natural vibrations of the steering wheel are excited during operation, which are perceived by the driver as unpleasant and disturbing. Various vibration patterns of the steering wheel can contribute to this problem, each to a certain extent. These vibration patterns can be divided into two categories: global vibrations, in which the entire steering wheel vibrates, and rim-dominant vibration patterns, in which only the steering wheel rim vibrates.

[0003] To solve the problem, the idea of ​​inserting a steel insert into the steering wheel has already been considered. This insert would add mass and stiffen the steering wheel. However, this measure has proven insufficiently effective in reducing the aforementioned vibrations.

[0004] From DE 39 27 383 A1, a motor vehicle steering wheel with a steering wheel rim is already known, comprising a rim skeleton with a tubular cross-section and a rim shell enclosing it. A cavity arranged in the rim skeleton is filled with a fluid medium, in particular a water-oil emulsion or a glycol-water mixture, to reduce the moments of inertia.

[0005] DE 201 04 043 U1 discloses a device for damping vibrations in a steering wheel, comprising a damping element and a damping mass. The damping element is coupled to an electrical control unit which can modify the mechanical vibration characteristics of the device by supplying electrical energy to the damping element, thus damping different vibration characteristics.

[0006] US Patent 2003 / 0233905A1 describes a steering wheel for a motor vehicle that is improved by targeted vibration damping. The steering wheel comprises a core with an annular rim into which one or more damping elements made of a material with a higher density than the rim core are integrated. These damping elements are preferably inserted into a channel structure embedded in the rim and subsequently fixed in vibration-damping contact with the steering wheel core by means of an injection-molded material (e.g., foam or plastic).

[0007] US Patent 2008 / 0134832A1 describes a steering wheel for a vehicle that includes a rim forming the outer circumference of the steering wheel. A flexible, circumferential weight element in the form of a braided cable is attached to the rear or, alternatively, the front of the rim, running completely or partially around the rim. This cable may be housed in a groove within the rim and secured by various fasteners such as retaining arms, adhesive tape, mechanical connectors, or a covering material. The steering wheel assembly also includes a central section with a hub, spokes, and optionally integrated controls. The cable is positioned and secured so that it is held in a predetermined position during manufacturing and subsequently permanently fixed with a covering material, such as foam or polyurethane.

[0008] DE 20 2004 009 692 U1 discloses a vehicle steering wheel comprising a steering wheel frame and a steering wheel cover, in which at least one container is arranged. This container holds a vibration damper in the form of a flowable material, such as sand or a liquid. The container is only partially filled to allow the material freedom of movement. It is preferably located within the steering wheel cover and can be at least partially integrated into the U-shaped cross-section of the steering wheel frame. The container can also be under negative pressure. The cross-section of the container is circular or trapezoidal.

[0009] From DE 101 40 473 A1, a vehicle steering wheel is known in which at least one metal element with a high specific gravity is elastically mounted to the steering wheel to dampen torsional vibrations. This metal element is preferably located in the region of the largest possible steering wheel diameter, usually in the steering wheel rim, and is embedded there in such a way that it can perform slight relative movements around the steering wheel's center point. The elastic mounting is achieved via an elastomer element or other elastic suspensions such as spring elements. The metal element can, for example, be ring-shaped and either completely surrounded by elastomer material or elastically suspended from a cover. Materials for the metal element include brass or steel, while the steering wheel itself can be made of lighter materials such as aluminum or magnesium.

[0010] Against this background, the invention aims to provide a steering wheel in which the aforementioned oscillations and vibrations are reduced during vehicle operation.

[0011] The first problem is solved with a steering wheel according to the features of claim 1. The dependent claims relate to particularly advantageous further developments of the invention.

[0012] According to the invention, a steering wheel is provided in which the cavity is bounded by a wall surface of the rim skeleton and by a wall surface of the rim shell, which is made of an elastically deformable material. The medium arranged in the cavity consists of a plurality of loose particles. Loose particles are understood to be particles, for example, granules, grains, or chips, which are present as bulk material and are not interconnected. The particles are in contact with each other and at least partially bear against the wall surfaces of the rim skeleton and the rim shell that define the cavity. During vehicle operation, the vibration amplitude is reduced or damped by energy dissipation through interaction of the particles with each other, in particular through rubbing, impact, and / or rolling, and through interaction of the particles with the elastically deformable rim shell of the steering wheel.In this process, the introduced vibrations are converted into other forms of energy, particularly heat. Furthermore, the particles introduce additional mass into the steering wheel, which shifts the natural frequency of the steering wheel from a high-frequency oscillation towards a lower-frequency oscillation. Unlike the steel insert mentioned earlier, the additional mass formed by the particles does not introduce significant stiffness into the system, as the particles are connected solely through mutual contact. The damping behavior can be adjusted and adapted to the specific application by controlling the particle density or pressure within the cavity, as well as the number and size of the particles.Due to the small particle size and large number of particles, there is intensive interaction between the particles and with the steering wheel, resulting in high energy dissipation combined with high damping. By changing the particle pressure, both the stiffness of the steering wheel rim and the interaction of the particles can be altered.

[0013] Furthermore, according to the invention, at least two radially extending partition walls are provided in the cavity. This allows the particles to be arranged in sectors, thereby simplifying the filling of the steering wheel rim during manufacturing.

[0014] It has proven particularly advantageous that the wall surface of the rim skeleton forms an open channel, which is closed by the wall surface of the rim casing, thus forming the cavity. The rim skeleton ensures the stability of the steering wheel rim and simultaneously provides the receiving space for the particles. The elastically deformable wall surface allows for intensive interaction between the particles and the wall surface, as well as among the particles themselves.

[0015] In this context, a U-shaped design for the wreath skeleton has proven particularly practical. However, a V-shaped or half-shell design is also possible.

[0016] It is particularly advantageous that the ring shell is made of an elastomer and vulcanized onto the ring skeleton. After vulcanization, some of the particles are embedded in the wall surface of the ring shell that defines the cavity.

[0017] A particularly advantageous embodiment of the invention is also achieved by forming the multitude of particles from quartz sand or metal particles. In particular, the use of quartz sand results in intensive interaction between the particles themselves and between the particles and the steering wheel rim, leading to significant energy dissipation.

[0018] A further embodiment of the invention provides that the cavity extends in a ring-shaped circumferential manner around the steering wheel rim, or that the cavity extends in a limited sector of the steering wheel rim, or that several spaced-apart cavities extend in several limited sectors. This allows the loose particles to be arranged in the steering wheel rim or in the cavity depending on the vibration mode to be damped.

[0019] Advantageously, at least one radially extending partition is provided in the cavity. This simplifies the arrangement of the particles into sectors and the filling of the steering wheel rim during manufacturing.

[0020] The invention allows for numerous embodiments. To further illustrate its basic principle, one of these is shown in the drawing and described below. This shows in Fig. 1. A steering wheel in a perspective view; Fig. 2. a cut along line AA in Fig. 1; Fig. 3 a diagram of the resulting vibration amplitudes of differently designed steering wheels.

[0021] Fig. Figure 1 shows a steering wheel 1 for a vehicle with a steering wheel hub 2, which is connected to an annular, circumferential steering wheel rim 4 by means of several steering wheel spokes 3. The steering wheel rim 4 is the part of the steering wheel 1 that is usually gripped by the driver during vehicle operation. The steering wheel hub 2 is connected to a steering column (not shown), through which vibrations from the road surface and / or the vehicle's components are transmitted to the steering wheel 1.

[0022] As from the in Fig. As can be seen in the sectional view shown in Figure 2, the steering wheel rim 4 consists of a circumferential rim skeleton 5 and an outer rim shell 6 made of an elastically deformable material, for example, an elastomer. The U-shaped rim skeleton 5 is made of a suitable metal and ensures the stability of the steering wheel rim 4. A multitude of loose particles 8, for example, quartz sand or metal particles, are arranged in a cavity 7 of the steering wheel rim 4. The cavity 7 is bounded by a wall surface 9 of the rim skeleton 5 and a wall surface 10 of the rim shell 6. The multitude of particles 8 are arranged in the cavity 7 such that they contact each other and at least partially bear against the wall surfaces 9 and 10 of the rim skeleton 5 and the rim shell 6.

[0023] During vehicle operation, the interaction of the particles 8 with each other, in particular through rubbing, impact, and / or rolling, and with the elastically deformable rim 6 of the steering wheel rim 4 or the steering wheel 1, results in a reduction or damping of the vibration amplitude through energy dissipation. In this process, the introduced vibrations are converted into other forms of energy, especially heat. Furthermore, the particles 8 introduce additional mass into the steering wheel 1, which leads to a frequency shift in the natural frequency of the steering wheel 1.

[0024] Fig.Figure 3 shows the resulting vibration amplitude of a steering wheel 1 without a damping device (curve a), a steering wheel 1 with a steel insert (curve b), and a steering wheel 1 according to the invention with a plurality of particles 8 (curve c). The effect achievable by the introduced particles 8 is clearly visible, namely, on the one hand, a strong amplitude reduction through energy dissipation and, on the other hand, a frequency shift due to the additional mass without a significant increase in stiffness. Reference symbol list 1 steering wheel 2 Steering wheel hub 3 steering wheel spokes 4 Steering wheel rim 5 Wreath skeleton 6 wreath covers 7 Cavity 8 particles 9 wall surface 10 wall surface a curve b curve c curve

Claims

[1] Steering wheel (1) with a steering wheel rim (4) comprising a rim skeleton (5) and a rim shell (6) at least partially enclosing the rim skeleton (5), wherein the rim skeleton (5) has a cavity (7) which is at least partially filled with a medium, and the cavity (7) is bounded by a wall surface (9) of the rim skeleton (5) and by a wall surface (10) of the rim shell (6) which is made of an elastically deformable material, wherein the medium arranged in the cavity (7) consists of a plurality of loose particles (8), characterized by , that at least two radially extending partitions are provided in the cavity (7) so that the particles (8) can be arranged in sectors. [2] Steering wheel (1) according to claim 1, characterized by , that the wall surface (9) of the wreath skeleton (5) forms an open channel which is closed by the wall surface (10) of the wreath shell (6) forming the cavity (7). [3] Steering wheel (1) according to claim 1 or 2, characterized by , that the wreath skeleton (5) is u-shaped or v-shaped. [4] Steering wheel (1) according to any of the preceding claims, characterized by , that the wreath shell (6) consists of an elastomer. [5] Steering wheel (1) according to any of the preceding claims, characterized by , that the wreath shell (6) is vulcanized onto the wreath skeleton (5). [6] Steering wheel (1) according to any of the preceding claims, characterized by , that some of the particles (8) are embedded in the wall surface (10) of the wreath shell (6) which limits the cavity (7). [7] Steering wheel (1) according to any of the preceding claims, characterized by , that the multitude of particles (8) are formed by quartz sand or metal particles. [8] Steering wheel (1) according to any of the preceding claims, characterized by, that the cavity (7) extends in a ring-shaped circumferential manner in the steering wheel rim (4), or that the cavity (7) extends in a limited sector of the steering wheel rim (4), or that several spaced-apart cavities (7) extend in several limited sectors.

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