JP7754010B2 - Steering wheel - Google Patents

Description

The present invention relates to a steering wheel with a heating element provided in the steering section that is gripped and steered by the driver.

As a countermeasure against the cold in winter, steering wheels have been widely known, such as the configuration described in Patent Document 1, in which a heating element that generates heat when electricity is passed through the steering section that is gripped and steered by the driver is provided, and the heat generated by the heating element raises the temperature of the surface of the steering section.

Japanese Patent Application Laid-Open No. 2002-96740

In a steering wheel in which a heating element that generates heat when electricity is applied is provided in the steering section, it is desirable to have a configuration in which the temperature rise characteristic of the surface of the steering section is high in relation to the power input to the heating element, from the perspective of reducing power consumption.

The present invention aims to provide a steering wheel in which a heating element that generates heat when electricity is applied is mounted in the steering section, and which can improve the temperature rise characteristics of the steering section surface in response to the power input to the heating element.

A typical configuration of a steering wheel according to the present invention that solves the above-mentioned problems is a steering wheel comprising: a steering section that is gripped and steered by a driver, the steering section being formed by laminating multiple layers on a core material, with a heating element that generates heat when electricity is passed through the multiple layers; and a boss portion that is disposed inside the steering section and connected to the steering center shaft of the steering section, wherein the multiple layers of the steering section include an ore-containing layer that is disposed closer to the surface than the heating element and contains an ore that emits far infrared rays.

According to the present invention, a heating element that generates heat when electricity is applied is provided inside multiple layers laminated on a core material to form the steering portion of a steering wheel, and an ore-containing layer containing ore that radiates far-infrared rays is provided on the surface side of the heating element. As a result, the ore-containing layer is heated by the heat generated by the heating element and radiates a large amount of far-infrared rays, allowing the heating element and the ore-containing layer to raise the temperature of the surface of the steering portion, thereby improving the temperature rise characteristics of the surface of the steering portion in relation to the power input to the heating element.

It is also conceivable that the ore is mixed into the paint applied to the surface of the steering section. With this configuration, a large amount of far infrared rays is emitted from the part that the driver touches, making it easier for the driver's hands to warm up, further strengthening the driver's protection against the cold.

It is also preferable that the ore-containing layer contains multiple types of ore. This makes it possible to suppress the deterioration of the temperature rise characteristics of the steering surface caused by the decrease in emissivity of specific wavelength bands that occurs with various types of ore.

FIG. 1 is a plan view of a steering wheel according to an embodiment of the present invention. 2 is a cross-sectional view of the steering portion of the steering wheel taken along the line A1-A1 shown in FIG. 1. 1A and 1B are a plan view and a cross-sectional view of the heater layer of the steering section in an expanded state. FIG. 2 is a diagram showing the layer configuration of a skin layer, which is one of the multiple layers of the steering section.

The following describes a steering wheel 10 according to one embodiment of the present invention. The steering wheel 10 is mounted on a vehicle (not shown). In the following description, unless otherwise specified, the up-down direction refers to the up-down direction along the axial direction of a steering shaft (not shown), the front-rear direction refers to the front-rear direction perpendicular to the axial direction of the steering shaft when the vehicle is steered straight ahead, and the left-right direction refers to the left-right direction perpendicular to the axial direction of the steering shaft when the vehicle is steered straight ahead.

Figure 1 is a plan view of a steering wheel 10 according to one embodiment of the present invention. In Figure 1, to make the internal structure easier to see, the upper cover 3x is made transparent and only the outline is shown by a two-dot chain line. As shown in Figure 1, the steering wheel 10 comprises a steering section 1, a boss section 2 that is disposed inside the steering section 1 and connected to a steering shaft (not shown) that serves as a steering axis, and spoke sections 3 that connect the steering section 1 and the boss section 2. In addition, a lower cover (not shown) is provided on the underside of the steering wheel 10.

The steering unit 1 is an annular member that is gripped and rotated by the driver of the vehicle. The driver grips the steering unit 1 and rotates it around a steering shaft connected to the boss unit 2, thereby changing the direction of travel of the vehicle. The steering unit 1 is formed by laminating multiple layers, including a metal core 1a made of an aluminum alloy or the like, and a coating layer 1b (Figure 2) that covers the core 1a. Details of these multiple layers will be described later.

The boss portion 2 is a metal member located at the center of the steering unit 1 and connected to a steering shaft (not shown). The boss portion 2 has an axial hole 2a through which the steering shaft is inserted. With the tip of the steering shaft inserted and fitted into the axial hole 2a, the tip of the steering shaft is fastened with a nut, connecting the boss portion 2 and the steering shaft. The boss portion 2 is also molded integrally with a metal core material 2b.

In this embodiment, the core material 1a of the steering section 1, the core material 2b of the boss section 2, and the core materials 3a1, 3b1, and 3c1 of the spoke section 3 (described later) are integrally molded by die-casting, thereby connecting the steering section 1, boss section 2, and spoke section 3. However, the core material 1a of the steering section 1, the core material 2b of the boss section 2, and the core materials 3a1, 3b1, and 3c1 of the spoke section 3 may also be formed separately and then connected by welding or the like.

Spoke portion 3 is composed of spoke portions 3a, 3b extending to the left and right sides from boss portion 2, and spoke portion 3c extending rearward from boss portion 2. Spoke portions 3a, 3b have metal core members 3a1, 3b1 extending to the left and right sides, respectively, connecting core member 1a of steering portion 1 with core member 2b of boss portion 2. Spoke portion 3c has metal core member 3c1 extending rearward from core member 2b of boss portion 2, branching left and right before connecting to core member 1a of steering portion 1. Spoke portions 3a, 3b, 3c also have resin upper covers 3x that cover core members 3a1, 3b1, 3c1.

Next, we will explain the details of the multiple layers laminated on the core material 1a of the steering section 1. Figure 2 is a cross-sectional view of the steering section 1 taken along the A1-A1 cross section shown in Figure 1. Figure 3 is a plan view and a cross-sectional view of the heater layer 1c, one of the multiple layers of the steering section 1, in an expanded state. Figure 4 is an enlarged cross-sectional view of region V shown in Figure 2, showing the layer structure of the skin layer 1d, one of the multiple layers of the steering section 1.

As shown in Figure 2, the steering section 1 is formed by layering, in order, the outer periphery of the core material 1a on the outer periphery of the core material 1a: a covering layer 1b made of foamed polyurethane that covers the core material 1a; a heater layer 1c having a heater wire 22; and a skin layer 1d made of synthetic leather. The skin layer 1d is divided into four parts circumferentially around the steering section 1, with one on each of the top, bottom, left, and right (see Figure 1). Although the four skin layers 1d each have slightly different shapes to match the shape of the area where they are installed, they all have the same layer structure, so the following description will only explain the structure of one skin layer 1d. Similarly, the heater layer 1c is divided into two parts circumferentially around the steering section 1, with one on each of the left and right sides. However, the two heater layers 1c differ only in their symmetrical shapes, so the following description will only explain the structure of the right heater layer 1c.

As shown in Figure 3, the heater layer 1c is composed of two substrates 20a and 20b that sandwich a heater wire 22 serving as a heating element, and is laminated and bonded to the outer periphery of the coating layer 1b with an adhesive (not shown). The substrates 20a and 20b are flexible sheets made of foamed polyurethane with a thickness of approximately 0.5 to 0.8 mm, and are bonded together with an adhesive (not shown). The density of the substrate 20b on the skin layer 1d side is higher than the density of the substrate 20a on the coating layer 1b side. This improves the insulating properties of the substrate 20a, suppressing heat conduction to the core material 1a side, and also improves the thermal conductivity of the substrate 20b, making it easier to conduct heat generated by the heater wire 22 to the skin layer 1d side, thereby improving the temperature rise characteristics of the surface of the steering section 1.

The heater wire 22 is constructed by winding multiple conductor strands made of tin-copper alloy wires with a strand diameter of approximately 0.08 mm around a heater core made of a bundle of aromatic polyamide fibers with an outer diameter of approximately 0.2 mm, spirally at a pitch of approximately 1.00 mm. The heater wire 22 is arranged between the substrates 20a and 20b in a predetermined unicursal pattern and is connected to lead wires 23 electrically connected to a control device (not shown). The control device controls the flow of electricity through the heater wire 22, causing it to generate heat and raise the temperature of the surface of the steering section 1.

As shown in Figure 4, the surface layer 1d is composed of a base fabric layer 1d1, an intermediate layer 1d2, a colored layer 1d3, and a protective layer 1d4 laminated in that order, and is adhered to the outer periphery of the heater layer 1c with an adhesive (not shown). The base fabric layer 1d1 is made of fibers such as nonwoven fabric, and is provided to ensure the shape retention of the surface layer 1d, improve the workability of adhering the surface layer 1d to the heater layer 1c, and to give the steering section 1 a hardness similar to that of natural leather.

The intermediate layer 1d2 is made of foamed polyurethane to provide elasticity, and is adhered to the outer periphery of the base fabric layer 1d1 via adhesive 35. The intermediate layer 1d2 is provided to give the steering section 1 an elastic feel similar to that of natural leather. The colored layer 1d3 is made of urethane paint containing a colorant, and is applied to the outer periphery of the intermediate layer 1d2. The color of the colorant contained in the colored layer 1d3 determines the color of the steering section 1 surface.

The protective layer 1d4, which serves as an ore-containing layer, is the layer placed on the outermost surface of the steering section 1 and is made of urethane-based paint, which is applied to the outer periphery of the colored layer 1d3. The protective layer 1d4 prevents the driver's hands from directly touching the colored layer 1d3, protecting it from wear and preventing the colorant from peeling off. The protective layer 1d4 also contains ore 30, which emits far-infrared rays. The ore 30 is crushed to approximately 100 μm and mixed into the paint that makes up the protective layer 1d4, and scattered throughout the entire protective layer 1d4. In this embodiment, the protective layer 1d4 contains approximately 5 to 10% by weight of ore 30.

In this way, by including ore 30 that emits far-infrared rays in the protective layer 1d4 on the surface side of the heater wire 22 in the steering section 1, the following effects are achieved. That is, according to Planck's law of radiation, the ore 30 is heated by the heat generated by the heater wire 22, thereby increasing the amount of far-infrared rays emitted from the ore 30. Furthermore, by including ore 30 in a layer on the surface side of the heater wire 22, the distance between the surface of the steering section 1 and the ore 30 is reduced, making it easier for the far-infrared rays radiated from the ore 30 to heat the surface of the steering section 1. As a result, the surface of the steering section 1 can be heated by the heat generated by the heater wire 22 and the far-infrared rays radiated from the protective layer 1d4, thereby improving the temperature rise characteristics of the surface of the steering section 1 in relation to the power input to the heater wire 22.

In addition, in this embodiment, the ore 30 is crushed into small pieces and mixed into the paint that makes up the protective layer 1d4, which is the outermost layer of the steering section 1, and then scattered throughout the entire protective layer 1d4. As a result, far infrared rays are emitted from the entire protective layer 1d4, which helps prevent uneven temperature rise on the surface of the steering section 1. In addition, since a large amount of far infrared rays is emitted from the parts that the driver touches, the driver's hands are more likely to be warmed, further strengthening the driver's protection against the cold.

In order to increase the emissivity of far-infrared rays and improve the heating characteristics of the surface of the steering section 1, the type of ore 30 preferably selected is one that contains the elements Si, Ca, and Mg in its chemical formula, such as tourmaline, silica, or calcium carbide, and is particularly preferably an ore 30 with an emissivity (ε) of 0.6 or higher. Furthermore, the ore 30 preferably has a thermal conductivity of 1 to 2 W/m·K or higher. Furthermore, by including multiple types of ore 30 in the protective layer 1d4, it is possible to suppress the deterioration of the heating characteristics of the steering section 1 due to the decrease in emissivity of various ores 30 in specific wavelength bands.

In this embodiment, the steering section 1 is described as containing ore 30 in the protective layer 1d4 of the surface layer 1d, but the present invention is not limited to this. That is, the same effect as above can be achieved by arranging the ore-containing layer containing ore 30 on the surface side of the steering section 1 relative to the heater wire 22. For example, crushed ore 30 may be mixed with a colorant into the paint that forms the colored layer 1d3 of the surface layer 1d, thereby containing the ore 30 in the colored layer 1d3. In this way, the ore 30 is coated with the protective layer 1d4, which prevents the ore 30 from peeling off from the steering section 1.

Alternatively, crushed ore 30 may be kneaded into the base fabric layer 1d1 of the surface layer 1d to form the base fabric layer 1d1 into ore-containing fibers, thereby incorporating the ore 30 into the base fabric layer 1d1. In this case, it is preferable to crush the ore 30 to approximately 0.5 μm and incorporate approximately 1% by weight of the base fabric layer 1d1. This prevents the ore 30 from coming into direct contact with the driver's hands, thereby preventing the ore 30 from peeling off from the steering section 1. Alternatively, the ore 30 may be incorporated into multiple layers that make up the surface layer 1d.

In addition, although this embodiment has been described with reference to a configuration in which the surface layer 1d is made of synthetic leather, the present invention is not limited to this, and natural leather may also be used. When using a surface layer 1d made of natural leather, possible configurations include mixing the mineral 30 into the coloring agent used to color the natural leather, or mixing the mineral 30 into a protective layer applied to the surface of the natural leather. Alternatively, a separate layer containing the mineral 30 may be provided between the surface layer 1d of natural or synthetic leather and the heater layer 1c.

In addition, although this embodiment has been described as providing a heater wire 22 as a heating element in the steering section 1 of the steering wheel 10, the present invention is not limited to this. That is, the same effect as above can be achieved by providing another general-purpose heater that generates heat when electricity is applied inside the steering section 1. However, in order to prevent the tactile feel of the steering section 1 from deteriorating, it is preferable to use a heater wire 22 with a small volume, as in this embodiment.

1...Steering section, 1a...Core material, 1c...Heater layer, 1d...Skin layer, 1d4...Protective layer, 2...Boss section, 10...Steering wheel, 22...Heater wire, 30...Ore

Claims (3)

a steering section that is gripped by a driver and steered, the steering section being formed by laminating a plurality of layers on a core material, and a heating element that generates heat when electricity is passed through the plurality of layers;
a boss portion disposed inside the steering portion and connected to a steering central shaft of the steering portion;
A steering wheel comprising:
The plurality of layers of the steering section include an ore-containing layer that is disposed on a surface side of the heating element and contains an ore that radiates far infrared rays ,
a heater wire as the heating element is sandwiched between the base materials on the core material side and the surface layer side;
A steering wheel characterized in that the density of the base material on the surface layer side is higher than the density of the base material on the core material side .
A steering wheel as described in claim 1, characterized in that the ore is mixed into paint applied to the surface of the steering section. A steering wheel as described in claim 1 or 2, characterized in that the ore-containing layer contains multiple types of ore.