Steering wheel covering member, steering wheel, and method for manufacturing steering wheel

There is provided a steering covering member in which it is possible to dispose a wire on a grip section in a wider range while a wrinkle or a slack is suppressed, a steering wheel including the steering covering member, and a method for manufacturing the steering wheel. The steering covering member includes a sheet-shaped sheet member having extensibility and a wire held by the sheet member. The sheet member is set to have a length, in a natural length, having a corresponding relationship with an inner circumferential-side length of a rim section main body portion. Both end portions of the sheet member in the longitudinal direction are disposed at positions corresponding to recessed portions of the rim section main body portion.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is entitled to and claims the benefit of Japanese Patent Application No. 2018-019333 filed on Feb. 6, 2018, the disclosure of which including the specification, drawings and abstract is incorporated herein by reference in its entirety.

TECHNICAL FIELD

The present invention relates to a steering wheel covering member that configures a grip section of a steering wheel, which is gripped and operated by a driver, in cooperation with a grip section main body portion, the steering wheel including the steering wheel covering member, and a method for manufacturing the steering wheel.

BACKGROUND ART

In recent years, an electric vehicle (EV) is widely used. The electric vehicle is configured of a combination of a rechargeable battery and a motor, and it is necessary to suppress consumption of accumulated power because energy needs to be replenished from an external charger, basically. In this respect, in order to suppress power consumption for heating (air conditioner) performed by high power consumption, a section is provided to cause warmth to be directly transmitted by a steering wheel that is directly touched by an occupant (driver). For example, a heater line as a heating element is buried in the steering wheel, and thereby it is possible to warm the steering wheel even when it is not long after a start, and various engines are not sufficiently warmed. Hence, when an automobile as a vehicle parked outside in winter is started and driven, for example, it is possible to suppress use of heating and suppress power consumption while there is a reduction in difficulty or discomfort of an operation due to a cold steering wheel.

As such a configuration, a steering wheel is known in which a heater unit provided with layout of a heater line on a sheet element is wrapped around a rim section of a cored bar or the like formed of a steering wheel base material. The rim section is formed along an arc and normally has an annular shape. Hence, when the sheet element having a substantially rectangular shape is formed to have a tubular shape and is wrapped as is, a wrinkle or a slack occurs at a position on an inner circumferential side due to a difference in length between inner and outer circumferences of the rim section, and the external appearance or tactile sensation of the rim section deteriorates. Therefore, a notch or the like is formed in sheet element, thereby, absorbing the difference in length between the inner and outer circumferences, and thereby an occurrence of the wrinkle or the slack is suppressed (for example, see PTL 1).

CITATION LIST

Patent Literature

SUMMARY OF INVENTION

Technical Problem

However, it is not possible to set the heater line at a position at which the notch is formed in the sheet element; thus, it is desirable to employ a configuration in which it is possible to set the heater line on the rim section in a wider range.

The present invention is made in this respect, and an object thereof is to provide a steering wheel covering member in which it is possible to perform layout of an element to be held on a grip section in a wider range while a wrinkle or a slack is suppressed, a steering wheel including the steering wheel covering member, and a method for manufacturing the steering wheel.

Solution to Problem

According to a first aspect, a steering wheel covering member that is wrapped around and fixed to a grip section main body portion which is formed along an arc and has recessed portions formed in a direction intersecting the arc and that configures a grip section of a steering wheel, which is gripped and operated by a driver, in cooperation with the grip section main body portion, the steering wheel covering member including: a sheet-shaped covering member main body; and an element to be held that is held by the covering member main body, in which the covering member main body has extensibility, has a length in a longitudinal direction, in a natural length, which is set to have a corresponding relationship with an inner circumferential-side length of the grip section main body portion, and has both end portions in the longitudinal direction at positions corresponding to the recessed portions.

According to a second aspect, a steering wheel having a grip section that is gripped and operated by a driver, in which the grip section includes a grip section main body portion that is formed along an arc and has recessed portions in a direction intersecting the arc, and the steering wheel covering member according to first aspect which covers, is wrapped around, and is fixed to the grip section main body portion.

According to a third aspect, in the steering wheel according to the second aspect, an adhesive is set on at least one of a covering member main body and the grip section main body portion in a region excluding a position corresponding to an outer circumferential side of the grip section main body portion and fixes the covering member main body.

According to a fourth aspect, a method for manufacturing a steering wheel that includes a grip section main body portion formed along an arc, a sheet-shaped covering member main body having extensibility and a length in a longitudinal direction, in a natural length, which is set to have a corresponding relationship with an inner circumferential-side length of the grip section main body portion, and a steering wheel covering member having an element to be held that is held by the covering member main body, the method including: matching positions of end portions of the covering member main body in the longitudinal direction with recessed portions formed in the grip section main body portion in a direction intersecting the arc; and wrapping the covering member main body around the grip section main body portion from a wrapping start on an inner circumferential side of the grip section main body portion to a wrapping end on the inner circumferential side thereof while the covering member main body extends on an outer circumferential side thereof and fixing the steering wheel covering member to the grip section main body portion.

According to a fifth aspect, the method for manufacturing a steering wheel according to the fourth aspect further includes setting an adhesive for fixing the covering member main body on at least any one of the covering member main body and the grip section main body portion in a region excluding a position corresponding to an outer circumferential side of the grip section main body portion.

Advantageous Effects of Invention

In the steering wheel covering member according to the first aspect, when the covering member main body has the extensibility, has the length in the longitudinal direction, in the natural length, which is set to have the corresponding relationship with the inner circumferential-side length of the grip section main body portion, thereby, being wrapped around and fixed to the grip section main body portion, both of the end portions of the covering member main body in the longitudinal direction are disposed to be matched with the positions corresponding to recessed portions of the grip section main body portion. The wrapping start of one edge portion of the covering member main body is performed along the inner circumferential side of the grip section main body portion, the covering member main body extends to be wrapped around at a position of the grip section main body portion on the outer circumferential side, and the wrapping end of the other edge portion of the covering member main body is performed on the inner circumferential side of the grip section main body portion. While the covering member main body is reliably positioned on the grip section main body portion by using the recessed portions, the covering member main body does not have a redundant length with respect to the grip section main body portion. Therefore, while an occurrence of a wrinkle or a slack is suppressed and the covering member main body is fixed to the grip section main body portion, it is possible to reduce positions such as notches for adjusting the length, at which it is not possible to perform layout of the element to be held in the covering member main body, and it is possible to perform the layout of the element to be held on the grip section in a wider range.

In the steering wheel according to the second aspect, since the steering wheel covering member according to the first aspect covers, is wrapped around, and is fixed to the grip section main body portion of the grip section, it is possible to suppress the wrinkle or the slack and improve the appearance, and it is possible to perform layout of the element to be held on the grip section in the wider range.

In the steering wheel according to the third aspect, in addition to an effect of the steering wheel according to the second aspects, the adhesive is set on at least any one of the covering member main body and the grip section main body portion in the region excluding the position corresponding to the outer circumferential side of the grip section main body portion. In this manner, it is possible to reliably fix the covering member main body to the grip section main body portion with the adhesive, extension of the covering member main body is unlikely to be hindered because the covering member main body does not easily adhere to the grip section main body portion when the covering member main body is wrapped around the grip section main body portion on the outer circumferential side while the covering member main body extends.

In the method for manufacturing a steering wheel according to the fourth aspect, the steering wheel covering member is fixed to the grip section main body portion formed along the arc, the steering wheel covering member having the covering member main body that has the extensibility, the length in the longitudinal direction, in the natural length, which is set to have the corresponding relationship with the inner circumferential-side length of the grip section main body portion, and both of the end portions in the longitudinal direction, which are disposed to be matched with the positions corresponding to the recessed portions of the grip section main body portion. The wrapping start of the one edge portion of the covering member main body is performed along the inner circumferential side of the grip section main body portion, the covering member main body extends to be wrapped around at a position of the grip section main body portion on the outer circumferential side, and the wrapping end of the other edge portion of the covering member main body is performed on the inner circumferential side of the grip section main body portion. While the covering member main body is reliably positioned on the grip section main body portion by using the recessed portions, the covering member main body does not have a redundant length with respect to the grip section main body portion. Therefore, while the occurrence of the wrinkle or the slack is suppressed and the steering wheel covering member is fixed to the grip section main body portion, it is possible to reduce positions such as notches for adjusting the length, at which it is not possible to perform layout of the element to be held in the covering member main body, and it is possible to perform the layout of the element to be held on the grip section in the wider range.

In the method for manufacturing a steering wheel according to the fifth aspect, in addition to effects of the method for manufacturing a steering wheel according to the fourth aspect, the adhesive is set on at least any one of the covering member main body and the grip section main body portion in the region excluding the position corresponding to the outer circumferential side of the grip section main body portion. In this manner, it is possible to reliably fix the covering member main body to the grip section main body portion with the adhesive, extension of the covering member main body is unlikely to be hindered because the covering member main body does not easily adhere to the grip section main body portion when the covering member main body is wrapped around the grip section main body portion on the outer circumferential side while the covering member main body extends.

DESCRIPTION OF EMBODIMENTS

Hereinafter, a configuration of an embodiment according to the present invention will be described with reference to the drawings.

InFIGS. 4, 5A, and 5B, reference sign10represents a steering wheel of an automobile as a vehicle, for example. Steering wheel10includes steering wheel main body11, pad body12which is mounted on an occupant side of steering wheel main body11, or the like. Steering wheel10is mounted on a steering shaft provided in a vehicle in a state of being inclined normally; however, hereinafter, when steering wheel10is viewed from a side of a driver (occupant), an arrow U direction is described as an upper side, an arrow D direction is described as a lower side, a front side, that is, a side of a front glass on an upper front side, of the vehicle is described as the front side or a back surface side, and a rear side, that is, a lower rear side, of the vehicle is described as the rear side, a near side, or a front surface side.

In this manner, steering wheel main body11is configured to include a rim section (grip section)15as a grip section, boss section16that is positioned on an inner side of rim section15, and a plurality of spoke sections17that connects rim section15and boss section16; here, in the embodiment, three spoke sections17are provided. In addition, steering wheel main body11has steering wheel base section18. In addition, steering wheel main body11has steering covering member20(hereinafter, simply referred to as covering member20) as a steering wheel covering member. Further, steering wheel main body11has outer skin section21. In this manner, steering wheel main body11has a cover body not shown.

Rim section15is a part that is gripped and operated by a driver (occupant). At least a part of rim section15is formed along an arc. In the embodiment, rim section15is formed into an annular shape. Hereinafter, sections of steering wheel main body11are disposed on the right, left, top and bottom sides with a (neutral) position of steering wheel10as a reference.

Steering wheel base section18has cored bar23and resin layer24that is covered with covering member20that covers a part of cored bar23.

Cored bar23is made of metal and includes substantially cylindrical boss25having a serration structure of intermeshing with the steering shaft on the back surface side which is a vehicle body side of boss section16, and boss plate26that configures the cored bar is integrally fixed to boss25. In this manner, spoke cored bar section27corresponding to spoke section17is formed to be integrally connected from boss plate26. Further, rim cored bar section28as a grip section cored bar corresponding to rim section15is fixed to spoke cored bar section27of spoke section17.

Spoke cored bar section27is radially provided. Spoke cored bar section27may not need to correspond to all of spoke sections17, or a part of spoke section17may be configured to have a finisher or a cover body without having spoke cored bar section27. In the embodiment, spoke cored bar section27projects from right, left, and lower portions of boss plate26and each of the spoke cored bar section is connected to rim cored bar section28.

Rim cored bar section28configures a part of rim section15. Rim cored bar section28is formed in a shape corresponding to a shape of rim section15. That is, rim cored bar section28is formed into an annular shape depending on the shape of rim section15; for example, at least a part of the rim cored bar section is formed along an arc. In the embodiment, rim cored bar section28is formed into an annular shape.

Resin layer24is formed to cover at least rim cored bar section28. In the embodiment, resin layer24is formed to cover entire rim cored bar section28and a part of spoke cored bar section27, for example. To be more specific, resin layer24is provided with rim covering section31as a grip section covering portion, which covers rim cored bar section28at the position of rim section15, and spoke covering section32that covers a region having a predetermined distance from an end portion that is connected to rim cored bar section28of spoke cored bar section27at the position of spoke section17, the rim covering section and the spoke covering section being integrally provided. In addition, resin layer24is formed to have a substantially circular cross section, for example. In this manner, resin layer24is made of a resin obtained by performing fine foaming on soft foaming polyurethane resin. In addition, resin layer24is provided with recessed portion33that is an outer skin splitting portion for fixing a part of outer skin section21. In this manner, resin layer24is formed by using a forming mold (die) not shown. The mold includes one half mold and the other mold, schematically, and a cavity that is formed between the one half mold and the other half mold is filled with a synthetic resin raw material.

Rim covering section31configures rim cored bar section28and rim section main body portion35as a grip section main body portion that configures rim section15. That is, resin layer24configures cored bar23and rim section main body portion35. At least a part of rim section main body portion35is formed along an arc. In the embodiment, rim section main body portion35is formed into an annular shape.

Spoke covering section32is connected to rim covering section31and projects from rim covering section31on a side of spoke cored bar section27. In the embodiment, spoke covering section32is formed at a position corresponding to right and left spoke sections17(spoke cored bar section27), for example.

Recessed portion33is formed in rim section main body portion35in a direction intersecting the arc (circumference) of rim section main body portion35. At least a part of recessed portion33is positioned on the rear side (front surface side) which as an occupant side on a front surface of resin layer24(rim section main body portion35). A plurality (in the embodiment, four) recessed portions33are formed and positioned to be separated from each other in a circumferential direction of rim section main body portion35. For example, recessed portions33are disposed at equal intervals (substantially intervals) in the circumferential direction of rim section main body portion35. In addition, the recessed portions33are each disposed in both side portions on an upper side and both side portions on a lower side. For example, recessed portions33may be formed at the same time as when resin layer24is formed by the forming mold or may be formed by performing processing after resin layer24is molded.

Since covering member20shown inFIGS. 1A to 3 and 5Bis referred to as a steering mat or the like, the covering member is disposed from a position to cover rim cored bar section28of resin layer24, that is, rim covering section31, to a position to cover a part of spoke cored bar section27, that is, spoke covering section32.

Covering member20includes sheet member (mat portion)41as a covering member main body formed into a sheet shape and wire42held as an element to be held that is held by sheet member41. Further, covering member20covers a front surface of resin layer24(rim section main body portion35) and is bonded to be fixed to the front surface of resin layer24(rim section main body portion35) with adhesive G (FIG. 1B). In the embodiment, covering member20is a heater unit for adjusting a temperature of rim section15, for example. That is, wire42of covering member20of the embodiment is a heater line (heating wire) which generates heat when energized and configures a heating circuit formed by a temperature sensor, or the like.

Sheet member41has extensibility. For example, sheet member41has a predetermined extension ratio and extends in a ratio of 10% to 15% in the embodiment. Sheet member41can be formed of any material; however, in the embodiment, the sheet member is formed of a synthetic resin such as vinyl chloride. In addition, a thickness of sheet member41can be set to any value; however, in the embodiment, the thickness is set to 1.0 mm or less with consideration for performance of covering member20as the heater unit. In the embodiment, sheet member41is integrally provided with a first covering portion that covers rim covering portion31(rim section main body portion35) and a second covering portion that projects from the first covering portion and covers a part of spoke covering portion32; however, the drawings only shows the first covering portion, and second covering portion is omitted in the drawing. Sheet member41(first covering portion) is formed into a rectangular shape. Longitudinal dimension L1which is a length of a long side of sheet member41(first covering portion) in a natural length is set to a length having a corresponding relationship with an inner circumferential-side length of rim section main body portion35(rim covering portion31of resin layer24). In addition, short dimension L2which is a length of a short side of sheet member41(first covering portion) in a natural length is set as a radial dimension (meridian (small diameter) dimension) of rim section main body portion35(rim covering portion31of resin layer24), that is, a dimension in a circumferential direction of a cross section thereof, or is formed to be equal (substantially equal) to a dimension in a meridian direction in a range to be warmed.

Here, longitudinal dimension L1of sheet member41(first covering portion) is set to the length having the corresponding relationship with the inner circumferential-side length of rim section main body portion35(rim covering portion31of resin layer24). This means that longitudinal dimension L1is set with the inner circumferential-side length as a reference. Specifically, longitudinal dimension L1of sheet member41(first covering portion) is set to be equal (substantially equal) to a dimension obtained by adding depths and inner circumferential-side lengths of recessed portions33to an inner circumferential-side length of a part of rim section main body portion35(rim covering portion31of resin layer24) excluding recessed portions33.

Sheet member41may be formed by joining through sewing or the like of sheet member pieces as a plurality of covering member main body pieces in the longitudinal direction.

Wire42is a functional part configured to be directly connected to a control circuit, a power supply, or the like not shown or to be indirectly connected thereto via a power receiving section or the like and, in the embodiment, to cause covering member20to perform detection when being energized or generate heat depending on the temperature of rim section15. Wire42can be disposed at any position; however, in the embodiment, the wire is disposed to meander in a wavy shape (FIG. 1A). That is, wire42is disposed to occupy a region having a predetermined plane shape with respect to sheet member41. A length (circuit length) of wire42is set depending on performance of covering member20as the heater unit or a shape of rim section main body portion35(rim covering portion31). In addition, a position of wire42on sheet member41can be set to any position; however, regarding an external appearance quality, it is preferable to set the wire inside sheet member41or on a side of rim section main body portion35(resin layer24(rim covering portion31)) of sheet member41. Further, wire42is disposed at a position excluding recessed portion33on rim section main body portion35(rim covering portion31of resin layer24). For example, wires42are disposed one by one on sheet member pieces that configure sheet member41, and a plurality of wires are disposed to be separated from each other by joining the sheet member pieces in the longitudinal direction. Therefore, the wires42are disposed to be separated from each other at a plurality of positions of sheet member41in the longitudinal direction, that is, four positions in the embodiment, and are disposed to be separated from both end portions in the longitudinal direction and both side portions in the longitudinal direction (both end portions in a transverse direction) of sheet member41. Hence, sheet member41(first covering portion) is provided with falling-in portion41athat falls in recessed portion33between adjacent wires42and42, and both end portions41band41bin the longitudinal direction are portions that fall in recessed portion33. In other words, joining portions of the sheet member pieces that configure sheet member41become falling-in portions41a, respectively. In the embodiment, falling-in portions41aare formed at three positions. In addition, dimension L3of falling-in portions41ain the longitudinal direction of sheet member41is set to have a corresponding relationship with the dimension of recessed portions33. For example, dimension L3of falling-in portions41ais set to be equal (substantially equal) to a dimension obtained by adding depths and inner circumferential-side lengths of recessed portions33to dimension L4of end portion41bin the longitudinal direction of sheet member41. In addition, in the embodiment, dimension L4of end portion41bof sheet member41(first covering portion) is set to be equal (substantially equal) to dimension L5of side portion (end portion in the transverse direction)41cwhich is an edge portion in the transverse direction of sheet member41, for example.

Adhesive G shown inFIGS. 1B, 2, and 5Bis to cause covering member20to adhere to and be fixed to resin layer24(rim section main body portion35). Adhesive G is set to be on at least any one of covering member20and resin layer24(rim section main body portion35). In the embodiment, adhesive G is set on a rear surface side of sheet member41of covering member20, that is, on a side of rim section main body portion35, in advance. In addition, adhesive G is not set at a position (region A) corresponding to the outer circumferential side of rim section main body portion35, but is set in a region (hatched part inFIG. 2) excluding region A. Hence, adhesive G is set along both side portions41cand41cof sheet member41.

Outer skin section21shown inFIGS. 5A and 5Bis a part that is directly gripped by the driver (occupant) and is a decorative part of steering wheel10. Outer skin section21is formed of leather such as natural leather or synthetic leather, a synthetic resin, or the like into a sheet shape. Outer skin section21covers covering member20and is attached to rim section main body portion35. For example, outer skin section21is disposed to cover covering member20and to continuously cover the entire front surface of rim section main body portion35. In the embodiment, both end portions of a plurality outer skin pieces45are joined by sewing or the like of each other to be integrally formed, and joining portions of the outer skin pieces fall in the positions of recessed portions33, respectively, such that outer skin section21configures a so-called grain-patterned design on the driver (occupant) side of rim section15. That is, in the embodiment, outer skin section21is formed by four outer skin pieces45.

The cover body is also referred to as a back cover, a lower cover, or a body cover, is formed of a synthetic resin or the like, and covers a lower portion of boss section16.

As pad body12, it is possible to use an airbag apparatus or a housing that houses an impact absorber, for example. Pad body12may be integrally assemble a horn switch mechanism as a switch apparatus.

In this manner, when steering wheel10is manufactured, cored bar23that has been formed in advance is set in the forming mold, and then a synthetic resin raw material is agitated and mixed to be injected into a cavity of the forming mold, in which the cavity is formed by combining (mold closing) one half mold and the other mold. As a result, reaction of the synthetic resin raw material is performed with foaming such that polyurethane is obtained and flows toward a flow terminal.

Subsequently, a first intermediate body formed with resin layer24covering rim cored bar section28in the cavity is released from the forming mold through mold opening of the one half mold and the other half mold, and burr or the like is cut.

Further, covering member20that is separately formed adheres to be fixed to the front surface of resin layer24(rim section main body portion35) of the first intermediate body. In this case, covering member main body pieces (sheet member pieces) are joined to each other in the longitudinal direction in advance such that covering member20is formed to have a longitudinal shape. As shown in FIG.6A1, position matching is performed by causing both end portions41band41bof sheet member41in the longitudinal direction to fall in one recessed portion33, and one side portion41cof sheet member41is fixed to an inner circumferential side of rim covering portion31(rim section main body portion35) of resin layer24with adhesive G. Falling-in portions41afall in to be fixed to the rest of recessed portions33, respectively. Longitudinal dimension L1of side portion41cof sheet member41is set to have a corresponding relationship with the inner circumferential-side length of rim section main body portion35and to be equal (substantially equal) to a dimension obtained by adding the depths and the inner circumferential-side lengths of recessed portions33to the inner circumferential-side length of the part of rim section main body portion35(rim covering portion31of resin layer24) excluding recessed portions33. Hence, one side portion41cof sheet member41is fixed to the inner circumferential side of rim covering portion31(rim section main body portion35) without substantial extension.

Subsequently, sheet member41is wrapped around rim section main body portion35on the outer circumferential side in the meridian direction with the inner circumferential side of rim section main body portion35as a wrapping start, while the side of the other side portion41cis stretched (FIGS.6A1and6B1). In this case, since adhesive G is not set at a position corresponding to the outer circumferential side of rim section main body portion35, it is possible to wrap sheet member41around rim section main body portion35on the outer circumferential side while a wrinkle or the like is stretched. In addition, sheet member41can extend between respective positions between recessed portions33and33, that is, between falling-in portions41aand41aor between falling-in portion41aand end portion41b.

In this manner, sheet member41is wrapped until the side of the other side portion41cthereof is positioned on the inner circumferential side of rim section main body portion35and is fixed on the inner circumferential side of rim covering portion31(rim section main body portion35) of resin layer24with adhesive G in the vicinity of one side portion41cwith the inner circumferential side as a wrapping end (FIGS.6A2and6B2). Longitudinal dimension L1of side portion41cof sheet member41is set to have a corresponding relationship with the inner circumferential-side length of rim section main body portion35and to be equal (substantially equal) to a dimension obtained by adding the depths and the inner circumferential-side lengths of recessed portions33to the inner circumferential-side length of the part of rim section main body portion35(rim covering portion31of resin layer24) excluding recessed portions33. Hence, one side portion41cof sheet member41is fixed to the inner circumferential side of rim covering portion31(rim section main body portion35) without substantial extension. As a result, covering member20is wrapped around rim section main body portion35and fixed thereto without causing a wrinkle or a slack in sheet member41. Adhesive G is spread when covering member20and rim section main body portion35(rim covering portion31) are brought into press contact with each other during fixing of the covering member, and it is also possible to fill a part corresponding to a portion (region A inFIG. 2), to which adhesive G is not set, with adhesive G. That is, adhesive G is not additionally applied during wrapping of covering member20.

Then, covering member20is further covered with outer skin section21. In this case, outer skin section21is joined by sewing or the like of the end portions of a plurality of outer skin pieces to each other in advance and has the same longitudinal shape as that of covering member20. Thus, joining portions fall in recessed portions33, respectively, and both end portions are joined by sewing or the like at a position corresponding to one recessed portion33. Hence, the outer skin section can fall in to be fixed to recessed portion33and can fall in to be fixed to recessed portion33while outer skin pieces are joined at the position of recessed portion33.

Steering wheel main body11electrically connects the functional parts of covering member20to the control circuit, and pad body12or the cover body is attached such that steering wheel10is completed (FIG. 4).

As described above, according to the embodiment, when sheet member41has the extensibility and has the length, in the natural length, which is set to have the corresponding relationship with the inner circumferential-side length of rim section main body portion35, thereby, being wrapped around and fixed to rim section main body portion35, both end portions41band41bof sheet member41in the longitudinal direction are disposed to be matched with the positions corresponding to recessed portions33of rim section main body portion35. The wrapping start of side portion41cwhich is one edge portion of the sheet member is performed along the inner circumferential side of rim section main body portion35, sheet member41extends to be wrapped around at a position of rim section main body portion35on the outer circumferential side, and the wrapping end of the other edge portion of sheet member41is performed on the inner circumferential side of rim section main body portion35. While sheet member41is reliably positioned on rim section main body portion35by using recessed portions33, sheet member41does not have a redundant length with respect to rim section main body portion35. Therefore, while the occurrence of the wrinkle or the slack is suppressed and covering member20is fixed to rim section main body portion35, it is possible to reduce positions such as notches for adjusting the length, at which it is not possible to perform layout of wire42in sheet member41, and it is possible to perform the layout of wire42on rim section15in the wider range.

In addition, since sheet member41can extend in portions split between recessed portions33and33which are used as positioning portions, it is possible to more reduce an extension error and it is possible to suppress the occurrence of the wrinkle or the slack more efficiently, compared with a case where entire sheet member41extends at once.

Since covering member20covers, is wrapped around, and is fixed to rim section main body portion35of rim section15, it is possible to suppress the wrinkle or the slack and improve the appearance, and it is possible to perform the layout of wire42on rim section15in the wider range and cause the wire perform a function thereof. In the embodiment, it is possible to warm the wide range of rim section15by wire42.

In addition, adhesive G is set on at least any one of sheet member41and rim section main body portion35in the region excluding the position corresponding to the outer circumferential side of rim section main body portion35. In this manner, it is possible to reliably fix sheet member41to rim section main body portion35with adhesive G, extension of sheet member41is unlikely to be hindered because sheet member41does not easily adhere to rim section main body portion35when sheet member41is wrapped around rim section main body portion35on the outer circumferential side while sheet member41extends.

Further, since covering member20is positioned and fixed by using recessed portions33for configuring a design by joining and falling-in of the end portions of outer skin section21to each other, there is no need to perform another process for forming a positioning portion of covering member20, and thus manufacturability is unlikely to deteriorate.

In the embodiment described above, covering member20may be a sensor unit that has, as the element to be held, a sensor circuit (a pressure sensor, an electric capacity sensor, or the like) that is to check that the occupant grips rim section15, for example. In this case, wire42functions as a detector of a sensor.

Further, the element to be held is not limited to wire42, and it is possible to use any functional part that configures a circuit section such as a heater circuit or a sensor circuit, for example. In addition, as the element to be held, it is possible to use a magnet (Massage Magnet), a decorative member, or the like other than the circuit section.

In addition, longitudinal dimension L1of sheet member41(first covering portion) is set to be slightly longer than the inner circumferential-side length of rim section main body portion35(rim covering portion31of resin layer24); however, the longitudinal dimension may be set to be slightly shorter with the inner circumferential-side length as a reference. In this case, when covering member20is wrapped around and is fixed to rim section main body portion35, the wrapping start is performed along the inner circumferential side of rim section main body portion35while side portion41cof sheet member41is slightly extended, and thereby it is possible to achieve the same operational effects.

Further, it is possible to set any number of recessed portions33at any positions depending on a design or the like of steering wheel10.

In addition, steering wheel10is not limited to the configuration in which three spoke sections17are provided, and can have a configuration in which two, four, or more spoke sections17are provided.

Further, rim section15may have the entirety or a part of the annular shape as long as the rim section has the arc shape. That is, rim section15may not have the annular shape as long as the rim section has the arc shape.

In this manner, steering wheel10can be used as the steering wheel for steering not only the vehicle such as the automobile but also any vehicle.

INDUSTRIAL APPLICABILITY

The present invention can be preferably used as a steering mat used for a steering wheel of an automobile such as an electric vehicle, for example, a steering wheel including the steering mat, and a method for manufacturing the steering wheel.

REFERENCE SIGNS LIST

10Steering wheel15Rim section as grip section20Steering covering member33Recessed portion35Rim section main body portion as grip section main body portion41Sheet member as covering member main body42Wire as element to be heldG Adhesive