JP7558759B2 - Steering wheel core structure - Google Patents

Description

The present invention relates to a core metal structure for a steering wheel, and in particular to a core metal structure for a steering wheel that is suitable for standardization of parts.

In vehicles such as automobiles, a steering wheel for steering the vehicle is attached to a steering shaft. Such steering wheels generally have a core metal that forms the frame and is coated with a synthetic resin such as urethane foam.

The core structure of a steering wheel generally has a boss core portion connected to a steering shaft, a rim core portion, and a spoke core portion connecting the boss core portion and the rim core portion, as described in Patent Document 1, for example, and is often integrally formed by casting from a magnesium alloy.

Patent Document 2 also discloses a core metal structure for an iron steering wheel that combines a two-part circular wheel rim, a boss located at the radial center of the wheel rim, and spokes that connect the wheel rim and boss in the radial direction, in order to give the wheel rim a structure that meets the required strength distribution.

International Publication No. 2016/136526 JP 2016-117441 A

However, steering wheels often have different designs for each vehicle model, and whether the core structure is one-piece or split, it must be designed for each design, which places a limit on how much production efficiency can be improved.

In addition, when magnesium alloys are used for the core wire, there are problems such as the difficulty of managing the manufacturing process, the large capital investment required, and the working environment, making it difficult to select or add manufacturing bases, making it difficult to quickly respond to changes in the business environment and needs.

The present invention was devised in consideration of these problems, and aims to provide a core bar structure for steering wheels that standardizes the core bar structure, improves production efficiency, and eases manufacturing conditions.

According to the present invention, there is provided a core metal structure for a steering wheel comprising a rim portion forming a gripping portion for a driver, a boss portion located at the center of the rim portion, and a spoke portion connecting the rim portion and the boss portion, wherein at least the rim portion and the spoke portions are separate parts, and a resin connecting member is provided for connecting the rim portion and the spoke portions, the connecting member comprises a main body portion covering the spoke portions, and a strength adjustment portion located on the main body portion, and the strength adjustment portion is composed of an elongated opening formed along the longitudinal direction of the spoke portions, and a reinforcing portion spanning the opening .

The rim portion and the spoke portion may be made of different metals.

The rim portion may be made of an aluminum alloy, and the spoke portion may be made of high tensile steel.

The boss portion and the spoke portion may be separate parts, and the connecting member may be configured to connect the boss portion and the spoke portion.

The boss portion may be made of a metal different from that of the spoke portion.

The boss portion may be made of a magnesium alloy.

The rim portion may have a ring shape made of pipe material.

The rim portion is configured to be separable into a first rim portion and a second rim portion, and the first rim portion and the second rim portion may be made of different materials.

The connecting member may include a cylindrical holding portion into which the rim portion is inserted, and an attachment portion to which an airbag module can be attached.

The reinforcing portion may be X-shaped, lattice-shaped or bar-shaped.

According to the core metal structure of the steering wheel of the present invention described above, the rim portion and the spoke portion are separate components that are connected by a connecting member, so that the core metal structure can be formed from materials appropriate to the functions required for each component, and the amount of magnesium alloy used can be reduced.

In addition, by making the connecting members out of resin, it is possible to standardize the rim and spoke parts, which are subject to fewer design changes, and adjust the parts that are subject to more frequent design changes with the connecting members. Therefore, according to the present invention, it is possible to standardize the core bar structure, improve production efficiency, and ease manufacturing conditions.

1A and 1B are diagrams showing a core metal structure of a steering wheel according to a first embodiment of the present invention, in which (A) is a perspective view and (B) is a parts exploded view. 5A and 5B are enlarged views showing a connecting member, in which FIG. 11A and 11B are diagrams showing modified examples of a connecting member, in which (A) shows a first modified example and (B) shows a second modified example. 11A and 11B are diagrams showing modified examples of the rim portion, in which FIG. 11A shows the rim portion and FIG. 11A and 11B are diagrams showing modified examples of the spoke portion, in which (A) shows a first modified example and (B) shows a second modified example. FIG. 11 is a component exploded view showing a core metal structure of a steering wheel according to a second embodiment of the present invention.

Embodiments of the present invention will be described below with reference to Figs. 1(A) to 6. Fig. 1 shows the core metal structure of a steering wheel according to a first embodiment of the present invention, with (A) being a perspective view and (B) being an exploded view of the components. Fig. 2 shows an enlarged view of a connecting member, with (A) being a perspective view and (B) being a plan view.

As shown in Figures 1(A) and 1(B), the steering wheel core structure 1 according to the first embodiment of the present invention comprises a rim portion 2 that forms the grip of the driver, a boss portion 3 that is located at the center of the rim portion 2, and spoke portions 4 that connect the rim portion 2 and the boss portion 3, with the rim portion 2, boss portion 3, and spoke portions 4 being separate parts, and a resin connecting member 5 that connects the rim portion 2, boss portion 3, and spoke portions 4.

The rim portion 2 has a ring shape made of, for example, a pipe material. By making the rim portion 2 out of a pipe material with a circular cross section, the amount of resin used to cover the rim portion 2 can be reduced, leading to cost and weight reduction. The rim portion 2 may be integrally formed into a ring shape, or may be divided into multiple arc-shaped bodies. Note that the configuration of the rim portion 2 is not limited to a pipe material, nor is it limited to a ring shape.

The rim portion 2 is the part that is gripped by the driver and does not require a large amount of strength. Also, since the rim portion 2 is also a part that may come into contact with an occupant in the event of a vehicle collision, it does not need to be very strong. Therefore, the rim portion 2 is made of, for example, an aluminum alloy. By using an aluminum alloy for the rim portion 2, it is possible to reduce the weight while ensuring the necessary rigidity. The material for the rim portion 2 is not limited to an aluminum alloy, and may be other metals such as iron.

The boss portion 3 is an important part that connects the steering wheel to the steering shaft. The boss portion 3 has, for example, a substantially cylindrical shape. The boss portion 3 is made of, for example, a magnesium alloy that has high strength and high corrosion resistance. However, the material of the boss portion 3 is not limited to magnesium alloy. The boss portion 3 may also have multiple positioning protrusions 31 that can be inserted into the through holes 41c formed in the spoke portion 4.

The spoke portion 4 is a member that connects the rim portion 2 and the boss portion 3, and is a component that supports the rim portion 2, and is therefore made of, for example, high-strength high-tensile steel. However, the material of the spoke portion 4 is not limited to high-tensile steel.

As described above, in this embodiment, the rim portion 2 is made of an aluminum alloy, the boss portion 3 is made of a magnesium alloy, and the spoke portion 4 is made of high tensile steel, so that each part is made of a different material. In the core metal structure 1 according to this embodiment, the rim portion 2, boss portion 3, and spoke portion 4 that make up the core metal structure 1 are each made of separate parts, so that each part can be made of a material according to the function required of each part.

As shown in FIG. 1B, the spoke portion 4 has a generally rectangular central portion 41 that forms a surface that is connected to the boss portion 3, and a pair of arm portions 42 that extend obliquely from both ends of the central portion 41 toward the rim portion 2. Note that the shape and configuration of the spoke portion 4 are not limited to those shown in the figure.

The center portion 41 may have an opening 41a for avoiding interference with the steering shaft, an opening 41b for avoiding interference with a fixing pin of an airbag module, a through hole 41c for positioning the boss portion 3, etc. At the tip of the arm portion 42, a curved receiving portion 42a for placing the rim portion 2 is formed.

The connecting member 5 is a part that connects the rim portion 2, boss portion 3, and spoke portion 4 together, which are made up of separate parts. The connecting member 5 has the function of connecting these parts and the function of fixing the airbag module, and is a part that is subject to large design changes. Therefore, it is made of a resin material such as fiber-reinforced plastic, which can flexibly accommodate design changes.

In contrast, the rim portion 2, boss portion 3, and spoke portion 4 are parts that are subject to few design changes, so by preparing parts with several different designs, it is possible to standardize these parts.

As shown in Fig. 2(A) and Fig. 2(B), the connecting member 5 includes a main body 51 that covers the spoke portion 4, a cylindrical holding portion 52 through which the rim portion 2 is inserted, and an attachment portion 53 to which an airbag module can be attached. The main body 51 has substantially the same shape as the spoke portion 4, and includes a center portion 51a and arm portions 51b. The holding portions 52 are disposed on both ends of the pair of arm portions 51b.

The central portion 51a may have an opening 51c formed therein to avoid interference with the steering shaft. The mounting portion 53 is disposed in the central portion 51a, and an extension portion 51d is formed therein to position the mounting portion 53 in accordance with the position of the fixing pin of the airbag module.

In this embodiment, it is assumed that the snap-in structure fixing pins are arranged at the phase positions of 90 degrees, 180 degrees, and 270 degrees. Note that the figure shows the state in which the coil spring 54 inserted into the fixing pin is arranged in the mounting portion 53.

The arrangement and shape of the mounting portion 53 often vary depending on the configuration of the airbag module to be attached, and the arrangement and shape of the mounting portion 53 are set according to the configuration of the airbag module. For example, if the fixing pin has a hook structure, the mounting portion 53 is arranged in a shape that corresponds to it.

The arm 51b may have, for example, an elongated opening 51e formed along the longitudinal direction and an X-shaped reinforcing portion 51f spanning the opening 51e. With this configuration, the strength of the connecting member 5 can be adjusted by increasing or decreasing the number of reinforcing portions 51f. In other words, the opening 51e and the reinforcing portion 51f form a strength adjustment portion for adjusting the strength. Note that the configuration of the strength adjustment portion is not limited to the configuration shown in the figure. For example, the reinforcing portion 51f may be lattice-shaped or bar-shaped.

The above-mentioned connecting member 5 is formed, for example, by temporarily assembling the rim portion 2, boss portion 3, and spoke portion 4 on a metal mold, and then pouring a resin material into the metal mold. Note that the connecting member 5 may be formed as a single unit, and then the rim portion 2, boss portion 3, and spoke portion 4 may be assembled to the connecting member 5.

Next, modified examples of each part will be described with reference to Figs. 3(A) to 5(B). Here, Fig. 3 is a diagram showing modified examples of the connecting member, with (A) showing a first modified example and (B) showing a second modified example. Fig. 4 is a diagram showing modified examples of the rim portion, with (A) showing the rim portion and (B) showing the connected state. Fig. 5 is a diagram showing modified examples of the spoke portion, with (A) showing the first modified example and (B) showing the second modified example.

The first modified example of the connecting member 5 shown in FIG. 3(A) has an increased number of reinforcing parts 51f that make up the strength adjustment part. Specifically, the reinforcing parts 51f are formed into two X-shapes. In this way, by increasing the number of reinforcing parts 51f, the strength of the connecting member 5 can be improved.

The second modified example of the connecting member 5 shown in FIG. 3(B) has a different arrangement of the mounting portion 53. In the second modified example, it is assumed that snap-in fixing pins are arranged at phase positions of 45 degrees, 180 degrees, and 315 degrees. In this way, the arrangement of the mounting portion 53 is set according to the configuration of the airbag module, and the extension portion 51d is formed accordingly. Even with such a design change, the connecting member 5 can be easily manufactured because it is made of resin.

The modified rim portion 2 shown in Figure 4 (A) has a split structure. Specifically, the rim portion 2 is configured to be split into a first rim portion 21 and a second rim portion 22, both of which have semicircular arc shapes. In this modified example, the second rim portion 22 is configured to be connectable by inserting both ends of the second rim portion 22 into both ends of the first rim portion 21.

As shown in FIG. 4(B), the second rim portion 22 is located on the driver's side, and the first rim portion 21 is located on the instrument panel side. Therefore, since the driver may come into contact with the second rim portion 22 in the event of a vehicle collision, the second rim portion 22 may be made of a metal that is softer than the first rim portion 21. The materials that make up the first rim portion 21 and the second rim portion 22 may be the same type of metal but with different strengths, or different metals but with different strengths.

The first modified example of the spoke portion 4 shown in FIG. 5(A) is one in which the arm portion 51b is positioned so that the central angle on the near side with respect to the center portion 51a is less than 180 degrees. The position and shape of the arm portion 51b are determined by the design of the steering wheel, and as shown in the figure, the position of the spoke portion 4 may be different.

The second modified example of the spoke portion 4 shown in FIG. 5(B) has the arm portion 51b formed from a separate part. In this way, by forming the spoke portion 4 from a combination of parts consisting of one center portion 51a and one arm portion 51b, the number of spoke portions 4 can be selected according to the design of the steering wheel, and they can be arranged at any central angle, allowing for greater standardization.

Next, the core metal structure 1 of the steering wheel according to the second embodiment of the present invention will be described with reference to FIG. 6. FIG. 6 is an exploded view showing the core metal structure of the steering wheel according to the second embodiment of the present invention. Note that the same components as those in the first embodiment described above are given the same reference numerals and duplicated descriptions will be omitted.

In the second embodiment shown in FIG. 6, the boss portion 3 and the spoke portion 4 are integrally formed. In this way, the boss portion 3 and the spoke portion 4 do not necessarily need to be separate parts. The integrally formed boss portion 3 and spoke portion 4 are made of a high-strength metal such as high-tensile steel or magnesium alloy. With this configuration, the number of parts can be reduced compared to the first embodiment.

According to the core metal structure 1 of the steering wheel according to the first and second embodiments described above, at least the rim portion 2 and the spoke portion 4 are separate components that are connected by a connecting member 5, so that the core metal structure 1 can be formed from materials according to the functions required for each component, and the amount of magnesium alloy used can be reduced.

In addition, by making the connecting member 5 out of resin, the rim portion 2 and spoke portion 4, which have few design changes, can be standardized, and the parts with many design changes can be adjusted with the connecting member 5. Therefore, according to this embodiment, the core bar structure 1 can be standardized, which improves production efficiency and eases manufacturing conditions.

The present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the spirit of the present invention.

1 Core metal structure 2 Rim portion 3 Boss portion 4 Spoke portion 5 Connecting member 21 First rim portion 22 Second rim portion 31 Protrusion 41 Center portion 41a, 41b Opening 41c Through hole 42 Arm portion 42a Receiving portion 51 Main body portion 51a Center portion 51b Arm portions 51c, 51e Opening 51d Expanding portion 51f Reinforcing portion 52 Holding portion 53 Mounting portion 54 Coil spring

Claims (10)

A core metal structure of a steering wheel including a rim portion forming a gripping portion for a driver, a boss portion disposed at a center of the rim portion, and spoke portions connecting the rim portion and the boss portion,
At least the rim portion and the spoke portion are separate parts,
a resin connecting member that connects the rim portion and the spoke portion,
The connecting member includes a main body portion that covers the spoke portion, and a strength adjustment portion disposed on the main body portion, and the strength adjustment portion is configured with an elongated opening portion formed along the longitudinal direction of the spoke portion, and a reinforcing portion that spans the opening portion.
A core metal structure of a steering wheel. The steering wheel core structure of claim 1, wherein the rim portion and the spoke portion are made of different metals. The steering wheel core structure of claim 2, wherein the rim portion is made of an aluminum alloy and the spoke portion is made of high tensile steel. The steering wheel core structure of claim 1, wherein the boss portion and the spoke portion are separate parts, and the connecting member is configured to connect the boss portion and the spoke portion. The steering wheel core structure of claim 4, wherein the boss portion is made of a metal different from that of the spoke portion. The steering wheel core structure according to claim 5, wherein the boss portion is made of a magnesium alloy. The steering wheel core structure of claim 1, wherein the rim portion has a ring shape made of a pipe material. The steering wheel core structure of claim 1, wherein the rim portion is configured to be separable into a first rim portion and a second rim portion, and the first rim portion and the second rim portion are made of different materials. 2. The steering wheel core structure according to claim 1, wherein the connecting member comprises a cylindrical holding portion into which the rim portion is inserted, and an attachment portion to which an airbag module can be attached. 2. The steering wheel core metal structure according to claim 1, wherein the reinforcing portion is X-shaped, lattice-shaped or bar-shaped.