Steering Wheel

Abstract

To provide a steering wheel which can improve the sensor sensitivity at a portion where the divided materials of a grip portion are coupled to each other, and which has an excellent durability of the divided material.SOLUTION: According to this steering wheel, an annular grip portion R that is gripped when a steering operation is given includes: a core material; a covering layer 10 that covers the core material; and a surface skin material 21 that covers the covering layer. The surface skin material employs a structure in which, at a back-surface-20b side, a sensor layer 23 that is composed of a conductive material capable of detecting the grip of the grip portion is placed, and a plurality of divided materials 21 divided along the circumferential direction of the grip portion are coupled to each other. The covering layer of the grip portion has, at the placed position of a coupled portion where the respective ends of the divided materials are coupled to each other, a recessed groove 11 along the cross-sectional circumferential direction of the grip portion. The respective ends of the adjoining divided materials have respective end edges 27 and 27 bent toward the core material so as to be laid over on each other, and coupled to each other by sewing using a conductive string 38 passing through in the thickness direction, and stored in the recessed groove of the covering layer.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a steering wheel having a sensor layer that can detect gripping of an annular grip portion that is gripped when steering. [Background technology]

[0002] Conventionally, in this type of steering wheel, the annular grip part that is gripped during steering is configured with a core material, a covering layer that covers the core material, and a skin material that covers the covering layer, and the skin material is configured by connecting a plurality of divided materials that are divided along the circumferential direction of the grip part (for example, see Patent Document 1). In this steering wheel, the divided materials that make up the skin material have a three-layer structure and are composed of a base layer such as leather attached to the covering layer that covers the core material, an elastic layer laminated on the base layer, and a top coat layer painted on the elastic layer. The elastic layer is made of an elastomer containing a foaming material, and contains a conductive material to serve as a sensor layer that can detect electrostatic capacitance. In addition, the covering layer of the grip part has a groove that is arranged along the cross-sectional circumferential direction of the grip part at the position of the connecting portion that connects the ends of the divided materials to each other. The ends of adjacent split members are bent toward the core member, and the joints between the overlapping edges are accommodated in the grooves of the covering layer, and the skin material is disposed along the circumferential direction of the annular grip portion so as to cover the covering layer. Furthermore, adjacent split members are connected to each other by lead wires that are disposed so as to straddle the end faces of the split members bent toward the core member, thereby ensuring mutual electrical continuity. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-202446 A (Fig. 4) Summary of the Invention [Problem to be solved by the invention]

[0004] However, in conventional steering wheels, the mutual conduction between the sensor layers of adjacent divided materials is ensured by a lead wire connecting the end faces of the elastic layer bent toward the core material, and the lead wire is arranged on the core material side away from the outer surface side of the skin material. Therefore, at the connecting portion between adjacent divided materials, the lead wire detects the approach of the driver's finger through the triangular cross-sectional gap between the bent parts of the divided materials and the distance to the end face side of the bent part, and the distance from the surface side of the skin material to the lead wire is long, and further, a triangular cross-sectional gap (air layer) is also interposed, which reduces the sensitivity of detecting the capacitance. In this case, it is considered to deal with the problem by making the top coat layer of the divided material as thin as possible and bringing the elastic layer closer to the surface side of the grip part to improve the sensitivity of detecting the capacitance. However, if the top coat layer is made thin, the part held by the driver will be prone to wear and the elastic layer will be exposed, which will degrade the appearance and reduce detection accuracy, creating issues with the durability of the dividing material.

[0005] The present invention is devised to solve the above-mentioned problems, and has an object to provide a steering wheel in which the sensor sensitivity at the connection points between the segments of the grip portion can be improved and the segments have good durability. [Means for solving the problem]

[0006] In the steering wheel according to the present invention, a ring-shaped grip portion to be gripped during steering is configured to include a core material, a coating layer covering the core material, and a skin material covering the coating layer, a steering wheel in which the cover material is configured by connecting a plurality of divided members divided along a circumferential direction of the grip portion, the divided members having a sensor layer made of a conductive material on a back side thereof, the sensor layer being capable of detecting the grip of the grip portion, the sensor layer being made of a conductive material on a back side thereof, The coating layer of the gripping portion has a concave groove along the cross-sectional circumferential direction of the gripping portion at a position where a connecting portion that connects the ends of the divided members is arranged, The ends of adjacent dividing members are bent toward the core member, and the overlapping edges are connected to each other by stitching with conductive thread that penetrates in the thickness direction, and are housed in the grooves of the covering layer.

[0007] In the steering wheel of the present invention, even if the connection parts between the partitions are housed in the concave grooves of the covering layer, the folded edges of the adjacent partitions are connected to each other by stitching with a conductive thread that penetrates in the thickness direction. That is, the conductive thread is closer to the surface side of the skin material by the length of the seam than the end face of the edge of the partition, and the position of the conductive thread is closer to the position of the sensor layer itself in the general part of the partition material near the connection part in terms of the distance from the surface side of the skin material than in the conventional structure in which the end faces are connected to each other by a lead wire. And, since the conductive thread itself also functions as a sensor part, it is possible to suppress the difference in sensor sensitivity between the connection parts between the partitions and the general part nearby, and to improve the sensor sensitivity at the connection part. Furthermore, in the present invention, since the sensor layer is disposed on the back side of the skin material and covered by the skin material, the durability of the sensor layer against wear, i.e., the durability of the partition material, is also improved.

[0008] Therefore, in the steering wheel according to the present invention, it is possible to improve the sensor sensitivity at the connection sites between the divided members of the grip portion, and also to improve the durability of the divided members.

[0009] In the steering wheel according to the present invention, it is desirable that the edges of adjacent dividing members are arranged with a sewing portion between the vicinity of the bent portion bent toward the core member and the sewing portion of the conductive thread, where the overlapped edges are sewn together with a sewing thread.

[0010] In such a configuration, the edges of adjacent segments are connected together by sewing with a sewing thread in a way that reinforces the stitching of the conductive thread, thereby preventing the conductive thread from breaking.When the annular skin material formed by connecting the segments together is arranged to cover the outer surface of the coating layer of the gripping part, the segments do not separate even if pulled strongly, and the conductivity between the sensor layers of the segments can be stably ensured and the segments can be arranged on the outer surface side of the coating layer.

[0011] In the steering wheel according to the present invention, the dividing member is formed of leather and the sensor layer disposed on a back surface of the leather, It is preferable that the sensor layer is formed by applying a conductive paint to the back surface of the leather.

[0012] In this configuration, the leather with the sensor layer on its back surface is placed on the outer surface of the grip, improving the feel and design of the grip. The sensor layer can also be placed on the back surface of the skin by simply applying a conductive paint to the back surface of the leather. Therefore, the grip with the sensor layer can be easily formed using the same process as for a normal leather-wrapped steering wheel. [Brief description of the drawings]

[0013] [Figure 1] 1 is a schematic plan view showing a steering wheel according to an embodiment of the present invention; [Diagram 2] 2 is a cross-sectional view of a grip portion of the steering wheel according to the embodiment, corresponding to the II-II portion of FIG. 1. [Diagram 3] 3 is a schematic partial cross-sectional view of a grip portion of the steering wheel according to the embodiment, corresponding to the III-III portion of FIG. 1. [Figure 4] FIG. 4 is a plan view showing each divided member of the embodiment. [Diagram 5] 4 is a plan view showing a state in which a covering layer is molded on a core material in the steering wheel of the embodiment. FIG. [Figure 6]10 is a diagram illustrating a state in which both edges in the width direction of a dividing material of an embodiment are disposed on the inner peripheral edge side of a coating layer. FIG. [Figure 7] FIG. 11 is a schematic partial cross-sectional view showing a modified example in which the edges of adjacent divided members are sewn together. [Figure 8] 8 is an explanatory diagram showing a sewing method (straight stitching) of the stitched portion of the conductive thread between the edges shown in FIG. 7. FIG. [Figure 9] FIG. 11 is an explanatory diagram showing another method of sewing (overlock stitch) a conductive thread. [Figure 10] FIG. 11 is a schematic perspective view showing the state in which the edges of adjacent divided materials have been sewn together by overlocking. [Figure 11] FIG. 11 is an explanatory diagram showing yet another method of sewing conductive thread (half backstitching). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] An embodiment of the present invention will be described below with reference to the drawings. As shown in Fig. 1, a steering wheel W of the embodiment is configured to include a substantially annular grip portion R that is gripped when steering, a boss portion B in the center of the grip portion R, and spoke portions S (L, R, B) that connect the grip portion R and the boss portion B. The spoke portion S includes spoke portions SL, SR extending from the boss portion B to both the left and right sides, and a spoke portion SB extending rearward from the boss portion B. The steering wheel W is also configured to include an airbag device 50, indicated by a two-dot chain line, disposed on the upper side of the boss portion B, a steering wheel main body 1, and a lower cover (not shown) that covers the lower side of the boss portion B.

[0015] As shown in Figs. 1 and 5, the steering wheel main body 1 is configured with a core 3 made of a metal material such as an aluminum alloy that connects the grip portion R, the boss portion B, and the spoke portions S. The core 3 is configured with a grip core portion 4 disposed in the grip portion R, a boss core portion 5 disposed in the boss portion B, and spoke core portions 6 (L, R), 7 disposed in the spoke portions S (L, R, B) so as to connect the grip core portion 4 and the boss core portion 5. The boss core portion 5 has a steel boss 5a disposed therein that is connected to the steering shaft of the vehicle. The spoke core portion 6 is configured with spoke core portions 6L, 6R disposed in the left and right spoke portions SL, SR, and two spoke core portions 7, 7 disposed in the rear spoke portion SB, branching to the left and right at the boss core portion 5 side, and connected at the grip core portion 4 side.

[0016] As shown in FIG. 2, a coating layer 10 is disposed around the grip core portion 4 disposed in the grip portion R, and a skin material 20 having a sensor layer 23 is disposed on the surface side of the grip portion R.

[0017] As shown in Figs. 1 to 3 and 5, the covering layer 10 is disposed around the grip core portion 4 and around the spoke core portions 6 (L, R) and 7 adjacent to the grip core portion 4. The covering layer 10 is made of a synthetic resin material such as urethane having insulating properties, and is formed around the grip core portion 4 of the core material 3 and the spoke core portions 6 and 7 by injection molding or the like. The covering layer 10 has annular grooves 11 (LF, LB, RF, RB) disposed along the cross-sectional circumferential direction of the grip core portion 4 at both the left and right sides of the front and rear of the grip portion R (see Fig. 5). These grooves 11 (LF, LB, RF, RB) become wood grain grooves that accommodate the edges 27 of the adjacent divided members 21 (F, L, R, B) as shown in Fig. 3.

[0018] The skin material 20 is configured by arranging a sensor layer 23 made of a conductive material capable of detecting the grip of the grip portion R on the back surface 20b side, and connecting a plurality of (four in the embodiment) divided pieces 21 (F, L, R, B) divided along the circumferential direction of the grip portion R. In the embodiment, each divided piece 21 is formed from leather 22 as a divided material main body made of natural leather, synthetic leather, or the like, and a sensor layer 23 formed by applying a conductive paint to the back surface 22b side of the leather 22. In the embodiment, synthetic leather is used as the leather 22.

[0019] The conductive paint of the sensor layer 23 is made by compounding conductive fillers such as metal powders, such as silver particles, and carbon, into a paint made of a resin, such as urethane or silicone.

[0020] As shown in Figures 1 and 4, dividing material 21 is composed of four pieces: dividing material 21F arranged between the left and right grooves 11LF, 11RF on the front side of coating layer 10, dividing material 21L arranged between the front and rear grooves 11LF, 11LB on the left side of coating layer 10, dividing material 21R arranged between the front and rear grooves 11RF, 11RB on the right side of coating layer 10, and dividing material 21B arranged between the left and right grooves 11LB, 11RB on the rear side of coating layer 10.

[0021] Divider 21F has a substantially rectangular shape when spread out flat, and the other dividers 21L, 21R, and 21B have a substantially cross shape. Divider 21F has left and right edges 27, 27 connected to the upper edges 27, 27 of the adjacent left and right dividers 21L, 21R, respectively, in the state shown in Fig. 4. Divider 21B has left and right edges 27, 27 connected to the lower edges 27, 27 of the adjacent left and right dividers 21L, 21R, respectively, in the state shown in Fig. 4.

[0022] The outer peripheral side edge 25 and the inner peripheral side edge 26 of each divided member 21 (F, L, R, B), excluding the end edge 27, are arranged close to each other so as to be in close contact with each other when each divided member 21 (F, L, R, B) is arranged to cover the outer surface of the corresponding covering layer 10 using an adhesive (see FIG. 6), and are configured as the gripping portion R of the leather-wrapped steering wheel W. Note that, although the illustrated example shows a case where only an adhesive is used, the side edges 25, 26 may be sewn together. Also, in the side edges 25, 26 of the left, right, and rear divided members 21L, 21R, 21B, the boss side edges 25a, 26a near the middle are bonded to the end faces of the spoke portions SL, SR, SB of the covering layer 10 without being in close contact with each other.

[0023] The connecting portions 31 between the edges 27, 27 of adjacent divided members 21 (F, L, R, B) are each bent toward the gripping core portion 4 side of the core member 3, i.e., toward the sensor layer 23 side of each divided member 21, and the bent folded portions 28 of the edges 27, 27 are connected to each other by stitching with a conductive thread 37 that penetrates in the thickness direction (see Figure 3).

[0024] The conductive thread 37 is formed by, for example, inserting conductive metal or carbon into fibers such as polyester.

[0025] In the embodiment, a second stitching portion 33b is provided between the adjacent edges 27, 27 of the divided members 21 near the bent portion 28 bent toward the grip core portion 4 of the core member 3 and the stitching portion 33a of the conductive thread 37, where the overlapped edges 27, 27 are stitched together with the stitching thread 38. That is, the connecting portions 31 (LF, LB, RF, RB) between the edges 27, 27 in the embodiment are formed by providing stitching portions 33 using the conductive thread 37 and the stitching thread 38. The stitching portion 33 is configured to include a stitching portion 33a for conducting stitching with the conductive thread 37 and a stitching portion 33b for reinforcing stitching with the stitching thread 38. The stitching thread 38 is made of polyester, polyamide, or the like, and is made of thread having a higher tensile strength than the conductive thread 37.

[0026] In this embodiment, the conductive thread 37 and the sewing thread 38 are sewn together by parallel stitching.

[0027] Then, after the four divided members 21 (F, L, R, B) are connected to each other to form the annular skin material 20, each connecting portion 31 (LF, LB, RF, RB) is accommodated in the corresponding groove 11 (LF, LB, RF, RB) of the covering layer 10 of the steering wheel main body 1 and is covered with the covering layer 10 to which an adhesive has been applied. Thereafter, the outer peripheral side edge 25 side and the inner peripheral side edge 26 side of each divided member 21 (F, L, R, B) excluding the edge 27 are brought close to each other (see FIG. 6) and bonded to the covering layer 10, whereby the grip portion R of the leather-wrapped steering wheel W can be formed, and the steering wheel main body 1 can be formed.

[0028] Then, a lower cover (not shown) is attached to the lower side of the boss portion B, the boss core portion 5 is fitted onto the steering shaft of the vehicle and fastened with nuts, the steering wheel main body 1 is attached to the vehicle, and the airbag device 50 is attached to the upper side of the boss portion B, thereby forming the steering wheel W and mounting the steering wheel W on the vehicle.

[0029] When the airbag device 50 is installed, the lead wire 46 connected to the sensor layer 23 is connected to a grip detection circuit 45 capable of detecting the grip of the driver (see FIG. 1).

[0030] In a steering wheel W mounted on a vehicle, as shown in FIG. 2, when the fingers F of the driver's hand H approach the sensor layer 23 so as to grip the gripping portion R, a specified gripping detection circuit 45 detects an increase in capacitance, thereby detecting the driver's grip.

[0031] In the steering wheel W of the embodiment, even if the connecting portions 31 (LF, LB, RF, RB) between the divided members 21 (F, L, R, B) are housed in the recessed grooves 11 (LF, LB, RF, RB) of the covering layer 10, the bent end edges 27, 27 of the adjacent divided members 21 (F, L, R, B) are connected to each other by stitching with the conductive thread 37 that penetrates in the thickness direction. That is, the conductive thread 37 is closer to the front surface 20a of the skin material 20 than the end face 29 of the end edge 27 of the divided member 21 by the length dimension L1 of the seam allowance 35 (see FIG. 3), and in terms of the distance from the front surface 20a of the skin material 20, the position of the conductive thread 37 is closer to the position of the sensor layer 23 itself of the general portion 42 of the divided member 21 in the vicinity of the connecting portions 31 than in the conventional structure in which the end faces of the sensor layers are connected to each other by lead wires. And, since the conductive thread 37 itself also functions as a sensor portion, it is possible to suppress the difference in sensor sensitivity between the connecting portion 31 between the divided members 21, 21 and the general portion 42 in the vicinity thereof, thereby improving the sensor sensitivity at the connecting portion 31. Furthermore, in the embodiment, the sensor layer 23 is disposed on the back surface 20b side of the skin material 20 and is covered by the skin material 20, so that the durability of the sensor layer 23 against abrasion, i.e., the durability of the divided members 21, is also improved.

[0032] Therefore, in the steering wheel W of the embodiment, the sensor sensitivity at the connecting portion 31 between the divided members 21, 21 of the grip portion R can be improved, and the durability of the divided member 21 can also be improved.

[0033] In the steering wheel W of the embodiment, the edges 27, 27 of adjacent divided members 21, 21 are arranged with a sewing portion 33b that sews the overlapping edges 27, 27 together between the vicinity of the bent portion 28 bent toward the gripping core portion 4 of the core material 3 and the sewing portion 33a of the conductive thread 37.

[0034] Therefore, in the embodiment, the edges 27, 27 of adjacent split members 21, 21 are connected to each other by sewing with a sewing thread 38 so as to reinforce the sewing of the conductive thread 37, thereby preventing breakage of the conductive thread 37. When the annular skin material 20 formed by connecting each split member 21, 21 to each other is arranged to cover the outer surface 10a of the coating layer 10 of the gripping portion R, the split members 21, 21 do not separate from each other even if pulled strongly, and the conductive state between the sensor layers 23, 23 of the split members 21, 21 can be stably ensured and the split members can be arranged on the outer surface 10a side of the coating layer 10.

[0035] If the conductive thread 37 has sufficient tensile strength, the ends 27, 27 of the divided members 21, 21 may be sewn together using only the conductive thread 37, without using the sewing thread 38, as in the sewing portion 33A shown in Fig. 7. The sewing method for the sewing thread 37 in this sewing portion 33A is a straight stitch, similar to that of the embodiment, as shown in Fig. 8.

[0036] In addition, in the embodiments and modified examples, the stitching of the conductive thread 37 has been exemplified by a straight stitch, but the stitching of the edges 27, 27 together may be by an overlock stitch as shown in Figures 9 and 10, or a half backstitch as shown in Figure 11, and furthermore, as long as the edges 27, 27 can be sewn together, the stitching method is not limited to these.

[0037] Furthermore, in the steering wheel W of the embodiment, the dividing material 21 is formed from leather 22 as the dividing material main body and a sensor layer 23 arranged on the back surface 22b of the leather 22, and the sensor layer 23 is formed by applying conductive paint to the back surface 22b of the leather 22.

[0038] Therefore, in the embodiment, the leather 22 having the sensor layer 23 disposed on the back surface 22b is disposed on the outer surface of the gripping portion R, thereby improving the tactile feel and design of the gripping portion R. The sensor layer 23 can also be disposed on the back surface 20b side of the skin material 20 by simply applying a conductive paint to the back surface 22b of the leather 22. Therefore, the gripping portion R provided with the sensor layer 23 can be easily formed in the leather wrapping process in which the leather 22 having the sensor layer 23 disposed thereon is wrapped around the covering layer 10, as in the case of a normal leather-wrapped steering wheel.

[0039] As the dividing material body, a wood panel or the like can be used in addition to the leather 22. When using a wood panel as the dividing material body, it is sufficient to provide a through hole for passing the conductive thread 37 for sewing and sew the dividing materials together.

[0040] In addition, when the sensor layer 23 is provided by applying paint containing a conductive material to the back surface 22b side of the leather 22, the paint may be applied to the dividing material body (leather) 22 by brushing, spraying, or printing. Furthermore, since the sensor layer 23 only needs to detect an increase in capacitance when the driver's hand or finger approaches, the sensor layer 23 may be provided on the back surface 22b of the leather 22 by applying a conductive material or by attaching a tape material containing a conductive material.

[0041] Furthermore, in the steering wheel W of the embodiment, an approximately circular gripping portion R is exemplified, but as long as the circular skin material 20 made of multiple connected segments can be fitted onto the outer surface 10a side of the coating layer 10, the gripping portion R is not limited to a circular shape and may have various shapes such as a square ring or an elliptical ring. [Explanation of symbols]

[0042] 3... Core material, 4... Core material gripping part, 10... Coating layer, 11 (LF, LB, RF, RB)... Groove, 20... Skin material, 20b... Inner surface, 21 (F, L, R, B)... Dividing material, 22... (Dividing material body) Leather, 22b... Inner surface, 23... Sensor layer, 27... Edge, 28... Bending part, 31 (LF, LB, RF, RB)... (Connection part) Connection part, 33, 33A... (Sewing part) Sewing part, 33a... Conductive sewing part, 33b... Reinforcing sewing part, 37... Conductive thread, 38... Sewing thread, R... Gripping part, W... Steering wheel.

Claims

1. The annular grip portion to be gripped during steering is configured to include a core material, a coating layer covering the core material, and a skin material covering the coating layer, a steering wheel in which the cover material is configured by connecting a plurality of divided members divided along a circumferential direction of the grip portion, the divided members having a sensor layer made of a conductive material on a back side thereof, the sensor layer being capable of detecting the grip of the grip portion, the sensor layer being made of a conductive material on a back side thereof, The coating layer of the gripping portion has a concave groove along the cross-sectional circumferential direction of the gripping portion at a position where a connecting portion that connects the ends of the divided members is arranged, The ends of the adjacent divided members are bent toward the core member, and the overlapping edges are connected to each other by stitching with a conductive thread that penetrates the divided members in a thickness direction, and are housed in the groove of the covering layer. A steering wheel characterized in that the adjacent edges of the dividing members are arranged with a sewing portion between the vicinity of the bent portion bent toward the core member and the sewing portion of the conductive thread, where the overlapping edges are sewn together with sewing thread.

2. The annular grip portion to be gripped during steering is configured to include a core material, a coating layer covering the core material, and a skin material covering the coating layer, a steering wheel in which the cover material is configured by connecting a plurality of divided members divided along a circumferential direction of the grip portion, the divided members having a sensor layer made of a conductive material on a back side thereof, the sensor layer being capable of detecting the grip of the grip portion, the sensor layer being made of a conductive material on a back side thereof, The coating layer of the gripping portion has a concave groove along the cross-sectional circumferential direction of the gripping portion at a position where a connecting portion that connects the ends of the divided members is arranged, The ends of the adjacent divided members are bent toward the core member, and the overlapping edges are connected to each other by stitching with a conductive thread that penetrates the divided members in a thickness direction, and are housed in the groove of the covering layer. The dividing member is formed from leather and the sensor layer disposed on a back surface of the leather, A steering wheel characterized in that the sensor layer is formed by applying a conductive paint to the back surface of the leather.

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