JP2015067017A - Heater element for steering wheel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent lifting of a heater element thereby preventing an occupant from feeling discomfort.SOLUTION: A heater element 40 includes: a heat insulation sheet; a heat conductive sheet 43 overlapped with the heat insulation sheet; and heating elements 45 disposed between the heat insulation sheet and the heat conductive sheet 43 and respectively having heat transfer lines which generate heat by energization. The heat conductive sheet 43 includes a pair of facing edge parts 48 which extends in a longitudinal direction. An extension part 48a which further extends in the longitudinal direction is provided at one of the pair of facing edge parts.

Description

  The present invention relates to a heater element provided in a steering wheel.

  The heater element described in Patent Document 1 includes a heating wire, an inner skin provided outside the heating wire, an outer skin provided outside the inner skin, and an aluminum heat conduction welded to the outer skin. A sheet (soaking foil). In such a heater element, electrical insulation between the heating wire, which is a conductor, and the heat conductive sheet is ensured by an insulating layer such as an inner skin or an outer skin.

Japanese Utility Model Publication No. 63-11029

By the way, when sticking the heater element to the core of the steering wheel, if one end of one side of the heater element rides on the opposite end, a step may be formed after urethane molding, which may cause a poor appearance of the steering wheel. is there.
Further, if the gap between the end portions when the heater element is attached to the core bar in order to avoid the above problem, the range of heating by the heater element is narrowed, and the passenger is uncomfortable.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a vehicle-mounted heater element that does not cause discomfort to the occupant.

In order to achieve the above object, the invention according to claim 1 is a non-conductive base material, a heat conductive sheet superimposed on the base material, and between the base material and the heat conductive sheet. A heater element for a steering wheel provided with a heating wire that is disposed and generates heat when energized,
When the heater element is attached to the mandrel of the steering wheel, a gap is provided between the end portion of the base material and the other end portion, and the heat conduction sheet covers the end portion of the base material so as to cover the gap. The gist is that a more extended portion is provided.

In this configuration, when the heater element is attached to the core of the steering wheel, a gap is provided between the end of the base and the other end, and the base does not overlap with each other after urethane molding. There will be no steps.
In addition, by providing an extension that extends from the end of the base material to the heat conductive sheet, the extension covers the gap between the end of the base material that is formed when the heater element is attached to the cored bar. It is possible to widen the warm range when the occupant grasps the steering wheel.

  As described above, according to the same configuration, defects after urethane molding are eliminated, and when the occupant grasps the steering wheel, the warm range is widened, so that the user can feel comfortable.

  The gist of the invention according to claim 2 is that in the on-vehicle heater element according to claim 1, the heat conductive sheet has a notch.

According to the above configuration, the rim cored bar has an annular shape and a three-dimensional curved surface, whereas the heater element has a planar shape. Therefore, when a heater element is affixed to the rim cored bar, a surplus portion that is not involved in the affixing is generated in the heater element, and wrinkles may occur. In this respect, in the invention according to claim 2, in which the heater element has a notch in the heat insulating sheet and the heat conductive sheet, the notch absorbs the generation of the excess portion. Therefore, it is difficult for wrinkles to enter the heater element.
Moreover, the operation | work which sticks a heater element to the metal core of a steering wheel becomes easy by providing a notch part in a heat conductive sheet.

  The invention according to claim 3 is the invention according to claim 1 or 2, wherein the heater element has an adhesive layer on a surface opposite to the heat conductive sheet superimposed on the base material. The gist of the present invention is that the adhesive layer is affixed to the core of the steering wheel.

When the heater element is bent along the outer shape of the rim cored bar and the adhesive layer adheres to the rim cored bar, the heater element is attached to the rim cored bar. Become. Since this adhesive layer is provided in advance as a part of the heater element, it is not necessary to provide the adhesive layer on the rim core metal or the heat insulating sheet when the heater element is attached.

The side view of the steering wheel to which this is applied about one Embodiment of the vehicle-mounted heater element concerning this invention. FIG. 3 is a C arrow view of the steering wheel of FIG. 1. Sectional drawing which expands and shows the cross-section of the rim | limb part along line 3-3 in FIG. The fragmentary sectional view of the heater element in the same embodiment (partial sectional view along line 4-4 in FIG. 5). The top view of the heater element in the embodiment.

DESCRIPTION OF EMBODIMENTS Hereinafter, an embodiment of a vehicle heater element according to the present invention will be described with reference to FIGS.
As shown in FIGS. 1 and 2, a steering shaft (steering shaft) 11 that rotates about the rotation axis L1 is located in front of the driver's seat of the vehicle (leftward in FIG. 1). It is arranged in an inclined state so as to become higher toward the right side of (). A steering wheel 12 is attached to the rear end portion of the steering shaft 11 so as to be integrally rotatable.

FIG. 3 shows a cross-sectional structure of the rim portion 13 along the line 3-3 in FIG. 2, that is, a cross-sectional structure of the right side portion of the rim portion 13. Note that the cross-sectional structure of the left portion of the rim portion 13 is the same as the cross-sectional structure of the left portion. Therefore, the description of the cross-sectional structure of the left side portion is omitted.

  The steering wheel 12 includes a rim portion (sometimes referred to as a handle portion or a ring portion) 13, a pad portion 14, and a spoke portion 16 (see FIG. 2). The rim portion 13 is a portion that is gripped and rotated (steered) by the driver, and has a substantially annular shape centered on the rotation axis L1 (see FIG. 2).

  The pad portion 14 is disposed in a space surrounded by the rim portion 13. The front portion of the pad portion 14 is constituted by a lower cover 15 (see FIG. 1). A plurality of (three in this case) spoke portions 16 are provided between the rim portion 13 and the pad portion 14.

  In this embodiment, in order to specify the circumferential position of the rim portion 13 that is rotated (steered), in the present embodiment, “up”, “ “Bottom”, “Left”, “Right” shall be defined.

  Inside the rim portion 13, the spoke portion 16 and the pad portion 14 of the steering wheel 12, a metal core made of iron, aluminum, magnesium, or an alloy thereof is disposed. Among the core bars, the one located in the rim part 13 forms a skeleton part of the rim part 13, has a substantially annular shape when viewed from the driver side, and is called a rim part core bar 20.

  The rim cored bar 20 is disposed at a position away from the surface of the rim part 13 inwardly. As shown in FIG. 3, the rim cored bar 20 has an annular outer annular portion 21 centered on the rotational axis L1, an inner annular portion 22 centered on the rotational axis L1, and a rotational axis L1. And a connecting annular portion 23 that connects the outer annular portion 21 and the inner annular portion 22 at their rear portions. A space surrounded by the outer annular portion 21, the inner annular portion 22, and the connecting annular portion 23 is a groove portion 24 that opens on the front surface of the rim cored bar 20. The groove portion 24 is provided over substantially the entire circumference of the rim portion 13. By adopting such a structure having the groove portion 24, the rim cored bar 20 has a substantially U-shaped cross-sectional shape.

The connecting annular portion 23 has a curved surface portion 25 that curves so as to swell rearward. The outer annular portion 21 has a curved surface portion 26 that curves so as to bulge forward at the front end. In the outer annular portion 21, two flat portions 27 are formed at locations sandwiched between the curved surface portions 25 and 26. The inner annular portion 22 has a curved surface portion 28 that curves so as to swell forward. In the inner annular portion 22, two flat portions 29 are formed at locations sandwiched between the curved surface portions 25 and 28. Furthermore, the inner wall surface of the groove part 24 has a pair of plane parts 31 which oppose each other.

  As shown by the broken line in FIG. 2, the heater elements 40 are incorporated in the left and right side portions, which are locations where many drivers grip in the circumferential direction of the rim portion 13. More specifically, the heater element 40 is attached so as to cover the rim cored bar 20.

Hereinafter, the structure of the heater element 40 in the present embodiment will be described.
FIG. 4 shows a cross-sectional structure of the heater element 40. FIG. 5 shows a plan view of the heater element 40 in a developed state.

  As shown in FIGS. 4 and 5, the heater element 40 includes a heat insulating sheet 41, a heat conductive sheet 43, a heating element 45, and an adhesive layer 47.

  As shown in FIG. 4, the heat insulating sheet 41 is formed in a plate shape having a uniform thickness (about 2 to 3 mm in the present embodiment) by a flexible non-conductive heat insulating material. As this heat insulating material, an elastic and flexible resin material, such as urethane or rubber, is suitable. Incidentally, in order to improve heat insulation, it is preferable that the heat insulation sheet 41 is a foam. So, in this embodiment, the heat insulation sheet 41 is formed with the urethane foam. In addition, this heat insulation sheet 41 comprises the said base material.

  The heat conductive sheet 43 is for quickly diffusing the heat generated from the heating element 45, and is formed of a material having a thickness smaller than that of the heat insulating sheet 41 and high heat conductivity. Since the heat conductive sheet 43 is bent along the rim cored bar 20 similarly to the heat insulating sheet 41, the heat conductive sheet 43 is preferably thin. In the present embodiment, the heat conductive sheet 43 is formed of a conductive aluminum foil. The heat conductive sheet 43 is superimposed on the heat insulating sheet 41 and fixed to the heat insulating sheet 41 by a fixing means such as adhesion.

  The heating element 45 is disposed between the heat insulating sheet 41 and the heat conductive sheet 43, and generates a heating wire 45a that generates heat when energized, and an insulating layer 45b that electrically insulates between the heating wire 45a and the heat conductive sheet 43. It consists of

  The heating wire 45a only needs to generate heat when energized. For example, the heating wire 45a is formed of a wire having a large electrical resistance and generating heat when energized. Further, as shown in FIG. 5, the heating element 45 (heating wire 45a) is repeatedly bent and arranged so as to form a wave shape in the longitudinal direction of the heater element 40 (vertical direction in FIG. 5).

The insulating layer 45b is made of non-conductive resin or the like and covers the outer peripheral surface of the heating wire 45a.
The adhesive layer 47 is formed to have a uniform thickness over the entire surface of the heat insulating sheet 41 on the side opposite to the heating element 45.

  As shown in FIG. 5, the heater element 40 has a long shape in the unfolded state. The heater element 40 has a pair of opposed edge portions 48 extending in the longitudinal direction in a state of facing each other. Of the pair of opposing edges 48, one opposing edge 48 is provided with an extension 48 a that extends. The heat insulating sheet 41 and the heat conductive sheet 43 in the heater element 40 are formed with notches 49 extending from a plurality of locations of the opposing edge portions 48 toward the opposing edge portion 48. Here, each notch 49 is formed to become narrower as it goes away from each opposing edge 48. These notches 49 make it difficult for wrinkles to enter the heater element 40 when the heater element 40 is attached to the rim cored bar 20.

Here, the rim cored bar 20 has an annular shape when viewed from the direction of arrow C in FIG. The rim cored bar 20 includes an outer annular portion 21, an inner annular portion 22, and a connecting annular portion 23, and has a U-shaped cross section (see FIG. 3). As described above, the rim cored bar 20 has a three-dimensional curved surface. In contrast, the heater element 40 has a planar shape before being attached to the rim cored bar 20 (see FIG. 5). Further, among the constituent members of the heater element 40, in particular, the heat conductive sheet 43 is less likely to extend than the heat insulating sheet 41. Therefore, when the heater element 40 is affixed to the rim cored bar 20, a surplus portion that is not involved in the affixing of the heater element 40 is generated, and wrinkles may occur. In this embodiment, in the present embodiment in which the notched portions 49 are provided at a plurality of locations of the heat insulating sheet 41 and the heat conductive sheet 43 in the heater element 40, these notched portions 49 absorb the surplus portions. For this reason, it is difficult for wrinkles to enter the heater element 40 in a state where it is affixed to the rim cored bar 20.

After the heater element 40 is attached to the rim cored bar 20, the gap S is set so as to be generated between the facing edge and the facing edge of the heat insulating sheet. By setting the gap S in advance, one of the opposing edge portions of the heater element does not ride on the other. Further, an extension portion 48 a is provided in a direction orthogonal to the longitudinal direction from the tip of one opposing edge portion 48 of the heat conductive sheet 43 so as to cover the gap S. The extension portion 48a is wound around the opposite edge portion where the extension portion 48a is not provided so as to cover the gap S generated after the heater element 40 is attached to the rim cored bar 20, thereby covering the gap S. Since the length of the extension portion 48a is longer than the width of the gap S, the gap S can be reliably covered, and the warming range of the heater element can be prevented from decreasing.

Then, by attaching the heater element 40, a heat insulating sheet 41 functioning as a heat insulating part, a heating element 45, and a heat conductive sheet 43 functioning as a heat conductive part are sequentially arranged around the rim cored bar 20. Therefore, it is not necessary to form a heat insulating part around the rim cored bar 20 by molding. Further, since the adhesive layer 47 is provided in advance as a part of the heater element 40, it is not necessary to use a separate adhesive when the heater element 40 is attached.

Further, the rim cored bar 20 to which the heater element 40 is stuck is placed in a mold (not shown) as an insert, and an uncured urethane material is supplied into the mold for molding. At this time, the inside of the mold is decompressed, and much of the urethane material is supplied around the heater element 40. Thereafter, the urethane material is reaction-cured to form a covering portion 35 around the heater element 40 (see FIG. 3). A part of the urethane material is also filled in the groove 24 and the gap S of the rim cored bar 20 (see FIG. 3). Filled portions 51 and 53 are formed by reaction hardening of the urethane material in the filled groove portion 24.

The resin material forming the covering portion 35 and the filling portion 51 is the same type as the heat insulating sheet 41 and is made of a resin material (in this case, urethane) having compatibility with the heat insulating sheet 41. Therefore, the filling part 51 is attached to the heat insulating sheet 41 and integrated. In other words, the covering portion 35 is attached to the heat insulating sheet 41 via the filling portion 51.

As described above, according to the present embodiment, the following effects can be obtained.
(1) When the heater element is attached to the mandrel of the steering wheel, a gap is formed between the end portion of the base material and the other end portion. Further, by providing an extension portion that extends from the end portion of the base material in the heat conductive sheet, the extension portion covers the gap between the end portions of the base material that is formed when the heater element is wound around the cored bar. be able to. Therefore, the base materials do not overlap each other, and a step is not formed after the urethane molding, and a warm range when the occupant holds the steering wheel can be widened.

Note that the present invention can be embodied in another embodiment described below.
-The insulating layer 45b was provided so that the outer peripheral surface of the heating wire 45a might be coat | covered. In addition, as long as it is provided so as to electrically insulate between the heating wire 45a and the heat conductive sheet 43, other arrangement modes may be used.

  -The heat conductive sheet 43 should just be what can diffuse the heat | fever which the heat generating body 45 emitted quickly, and what was formed with the material different from aluminum foil may be used as the heat conductive sheet 43. FIG. For example, the heat conductive sheet 43 may be made of copper foil.

  -The heat generating body 45 should just be what generate | occur | produces heat by electricity supply, and the thing different from the heating wire 45a mentioned above may be used as a heat generating member. For example, the heating element 45 may be formed by forming a resistor layer on an insulating sheet.

  -The heat generating body 45 may be arrange | positioned between the heat insulation sheet 41 and the heat conductive sheet 43 by the aspect different from the said embodiment. For example, the heating element 45 may be repeatedly bent so as to form a wave shape in the short direction of the heater element 40.

  The adhesive layer 47 in the heater element 40 may be omitted. In this case, the heater element 40 may be attached to the rim cored bar 20 by an adhesive, for example.

-The notch part 49 may be formed in the shape different from the said embodiment. Further, the notch 49 may be omitted.
-The heater element concerning this invention is applicable not only to the steering wheel 12 mentioned above but the heater element of other vehicle-mounted members, such as a shift knob and a seat.

DESCRIPTION OF SYMBOLS 11: Steering shaft 12: Steering wheel 13: Rim part 14: Pad part 15: Lower cover 16: Spoke part 20: Rim part core metal 40: Heater element 41: Thermal insulation sheet 43: Thermal conductive sheet 45: Heat generating body 45a: Heating wire 45b: Insulating layer 47: Adhesive layer 48: Opposing edge 48a: Extension 49: Notch

Claims (3)

For a steering wheel provided with a non-conductive base material, a heat conductive sheet superposed on the base material, and a heating wire disposed between the base material and the heat conductive sheet to generate heat when energized A heater element,
When the heater element is affixed to the mandrel of the steering wheel, a gap is provided between the end portion of the base material and the other end portion, and the heat conductive sheet is attached to the end of the base material so as to cover the gap. A heater element for a steering wheel, characterized in that an extended portion extending from the portion is provided. The heater element for a steering wheel according to claim 1, wherein the heater element has a notch in the heat conductive sheet. The heater element has an adhesive layer on a surface opposite to the heat conductive sheet superposed on the base material, and is adhered to the core metal of the steering wheel in the adhesive layer. The heater element for a steering wheel according to claim 1 or 2.

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