Steering wheel

Abstract

A steering wheel provided with a rim core, a resin part molded on the rim core, and a skin covering at least a portion of the surface of the resin part, the skin being an artificial blank, the steering wheel satisfying the relationships of formulae (1) and (2). Formula (1): 0.65 < = G / L < = 0.95, Formula (2): 1.05 < = G / R < = 1.35. L, R and G are hardness of a C-type durometer.

Description

Technical Field

[0001] The invention relates to a steering wheel. Background Art

[0002] As the structure of the steering wheel, for example, there are known structures that are formed of an elastomer resin layer provided on the surface of a metal rim material and modified to impart wear resistance to the surface as needed, and structures that cover the elastomer resin layer provided on the surface of the metal rim material with leather and then adhere or sew. In addition, there are also known technologies that impart various functions to the steering wheel or change the touch of the surface by changing or modifying the covering material itself provided on the surface of the steering wheel, or inserting a functional material between the covering material and the elastomer resin layer.

[0003] For example, Patent Document 1 discloses a steering wheel in which the leather covering the main body of the ring portion has a coating film as an invention in which the coating material itself is changed or modified in a structure having the coating material. The leather has a different function from the part without the coating film due to the coating film. As the different function, non-slip property or easy sliding property is described.

[0004] Patent document 2 discloses, as an invention comprising a rim material and an elastomer resin layer, a steering wheel having a resin portion around a rim core metal, wherein the resin portion is made of a rigid foamed polyurethane having a specific surface hardness. It is recorded that the rigid foamed polyurethane can impart wear resistance and weather resistance. Similar to patent document 1, patent document 3 discloses, as an invention having a structure in which the covering material itself is changed or modified, a skin component characterized in that the compression characteristics of the surface of the skin component are 1 cm / s per 1 cm under the maximum load. 2 For the displacement-load characteristics in the area below 30g, the load is 30g / cm 2 The compressive strain under the condition is 0.00527~0.0110cm, the compression recovery is 56~65%, and the average friction coefficient of the surface of the above-mentioned skin member is 0.2~0.4. It is recorded that the skin member improves the grip comfort.

[0005] Unlike seats and door trims, natural leather is mainly used for the surface leather material of the steering wheel that the driver constantly touches with his hands. However, in recent years, there is a demand to replace natural leather with artificial materials from the perspective of animal protection, and similar to Patent Document 1, as an invention for changing or modifying the covering material itself, development related to synthetic leather suitable for components of automobiles, etc. has been carried out.

[0006] For example, Patent Document 4 discloses a synthetic leather for automobiles in which a fibrous base material, a skin layer formed of a polyurethane resin, and a protective layer formed of a polyurethane resin are sequentially laminated. Patent Document 5 discloses a steering wheel provided with a covering material formed of soft urethane or the like. Patent Document 6 discloses a synthetic leather in which a fibrous base material, a touch-imparting layer formed of a gel-like substance, and a skin layer formed of a polyurethane resin are sequentially laminated.

[0007] Prior art literature

[0008] Patent Literature

[0009] Patent Document 1: Japanese Patent Application Publication No. 2018-69766

[0010] Patent Document 2: Japanese Patent Application Laid-Open No. 59-11963

[0011] Patent Document 3: Japanese Patent Application Publication No. 2006-101935

[0012] Patent Document 4: International Publication No. 2015 / 001732

[0013] Patent Document 5: Japanese Patent Application Publication No. 2021-20561

[0014] Patent Document 6: Japanese Patent Application Publication No. 2019-77961 Summary of the invention

[0015] Problems to be solved by the invention

[0016] In addition, from the perspective of the high-end feeling and touch given by the surface leather material of the steering wheel, suede-like synthetic leather, grain-like synthetic leather, etc. are replaced with natural leather. Such simple replacement of the surface leather material is well known. However, as a method for changing the grip of the steering wheel, there is no concept of changing it based on the understanding that the components other than the surface leather material are the basic structure of the steering wheel. Therefore, only focusing on the surface leather material, the grip is changed by simply changing its hardness and touch.

[0017] The automobile synthetic leather of patent document 4 is suitable as a vehicle seat, but it is a circular woven cloth-based synthetic leather, so it is soft and easy to stretch and is not suitable for the surface leather material of the steering wheel. In addition, patent document 4 does not disclose its surface leather material suitable for the steering wheel.

[0018] In addition, Patent Document 5 states that if the Asker C hardness of the covering material is set to 30 to 50, the driver can hold the grip portion with a good touch without being too soft or too hard. Patent Document 6 states that since the Asker C hardness of the touch-imparting layer is 0 to 15, the Asker C hardness of the synthetic leather is about 45. However, the synthetic leathers described in Patent Documents 5 and 6 are difficult to impart the severe wear resistance of a steering wheel and the reliable control feel when performing intense steering wheel operations such as emergency evasion.

[0019] There has been a long-standing demand for a steering wheel that uses synthetic leather as a surface leather material and that can achieve both a soft grip and a reliable control feel.

[0020] An object of the present invention is to provide a steering wheel that has a soft grip feeling when lightly gripped and a reliable steering feeling when firmly gripped.

[0021] Solutions to the problem

[0022] As a result of intensive studies to solve the above-mentioned problems, the present inventors have conceived of the present invention described below and have found that the problems can be solved.

[0023] That is, the present invention is as follows.

[0024] [1] A steering wheel comprising:

[0025] Rim core,

[0026] a resin portion molded on the rim core portion, and

[0027] a skin covering at least a portion of the surface of the resin portion,

[0028] The above-mentioned skin is artificial blank.

[0029] The steering wheel satisfies the following equations (1) and (2):

[0030] Formula (1): 0.65 ≤ G / L ≤ 0.95

[0031] Formula (2): 1.05 ≤ G / R ≤ 1.35

[0032] The above L represents a durometer hardness, which is a median value obtained from 10 measurements made by contacting a C-type durometer with the surface side of one of the above-mentioned skins placed on a plate having a D-type durometer hardness of 80 or more, wherein L is 10 or more and 100 or less.

[0033] The above R represents a durometer hardness, which is a median of 10 measurements obtained by contacting a C-type durometer with the surface of the resin portion molded on the rim core, wherein R is greater than or equal to 10 and less than or equal to 100.

[0034] The above G represents the durometer hardness, which is measured by bringing a C-type durometer into contact with the surface side of the above skin in a state where the surface of the resin portion molded on the above rim core is covered, and the median is calculated based on 10 measurement values, wherein G is greater than 10 and less than 100.

[0035] [2] The steering wheel according to [1] above, wherein:

[0036] The above-mentioned G is 50 or more and 90 or less.

[0037] [3] The steering wheel according to [1] or [2] above, wherein:

[0038] The above R is 75 or less.

[0039] [4] A steering wheel according to any one of [1] to [3] above, wherein:

[0040] The above L is 90 or less.

[0041] [5] A steering wheel according to any one of [1] to [4] above, wherein:

[0042] The above L is 75 or more.

[0043] [6] A steering wheel according to any one of [1] to [5] above, wherein:

[0044] The artificial blank is in a grain shape.

[0045] [7] A steering wheel according to any one of [1] to [6] above, wherein

[0046] The artificial blank is a laminate including a fiber base material layer and a resin coating layer.

[0047] [8] The steering wheel according to [7] above, wherein:

[0048] The fiber base material layer is a nonwoven fabric to which a resin is applied.

[0049] [9] A steering wheel according to any one of [1] to [8] above, wherein:

[0050] At least a portion of the skin is not bonded to the surface of the resin portion.

[0051] Effects of the Invention

[0052] According to the present invention, it is possible to provide a steering wheel that has a gentle grip feeling when lightly gripped and a reliable steering feeling when firmly gripped. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 This is a plan view of an example of a circular steering wheel according to the present embodiment as seen from the driver's seat side.

[0054] Figure 2 This is a plan view of an example of a D-shaped steering wheel according to the present embodiment as viewed from the driver's seat side.

[0055] Figure 3 It is a cross-sectional view of a rim portion in an example of a steering wheel according to the present embodiment.

[0056] Explanation of symbols

[0057] 1: Steering wheel

[0058] 2: Rim

[0059] 10: Rim

[0060] 11: Padding Department

[0061] 12: Spoke

[0062] 20: Rim core

[0063] 30: Resin Department

[0064] 40: Epidermis DETAILED DESCRIPTION

[0065] Hereinafter, an example of an embodiment of the present invention will be described. However, the embodiment described below is an example for embodying the technical idea of ​​the present invention, and the present invention is not limited to the following description.

[0066] In addition, preferred embodiments are shown in this specification, and a combination of two or more preferred embodiments is also a preferred embodiment. Regarding items expressed in numerical ranges, if there are some numerical ranges, their lower limits and upper limits can be selectively combined into a preferred embodiment.

[0067] In addition, in this specification, when there is a description of a numerical range of "XX to YY", it means "XX or more and YY or less".

[0068] The "steering wheel" of the present embodiment refers to a part that a driver holds and rotates to steer a vehicle. As described later, the shape of the "steering wheel" of the present embodiment is not limited to a ring shape.

[0069] The steering wheel of this embodiment has at least a rim core, a resin portion, and a skin, and the skin is an artificial blank. The artificial blank of the present invention refers to a blank whose structure, which is the basis of the blank shape, is not a natural blank but is formed by an artificial process, and does not mean that the raw material is formed only by artificial substances. Specifically, natural leather pieces and natural wooden panels obtained by using the skin of animals and plants as raw materials without destroying their shapes are natural blanks, and blanks formed by forming basic structures such as fabrics, knitted fabrics, non-woven fabrics, and molded sheets using crushed materials of the skin of animals and plants such as natural leather and natural trees, cotton yarn, silk threads and other natural fibers as raw materials, and blanks formed by further impregnating or coating them with resins are all artificial blanks. In addition, blanks formed by forming the above-mentioned basic structures using artificial substances such as synthetic fibers and synthetic resins as raw materials are all artificial blanks.

[0070] The inventors of the present invention have conducted various studies on a steering wheel that has a soft grip when lightly gripped and a reliable sense of control when performing intense operations such as emergency evasion. The prior art only focuses on the surface leather material, and it is difficult to change the grip by simply changing its hardness and touch. On the other hand, the inventors of the present invention focused on the hardness of the resin part and the surface skin, and found that it is an effective method for the hardness to satisfy a specific relationship (specifically, the relationship between the above formula (1) and formula (2)).

[0071] Based on the results, the present inventors have discovered that the above-mentioned problems can be solved by satisfying the relationship between the above-mentioned formulas (1) and (2); and by utilizing an artificial process to form at least the basic structure of the blank for the skin, a skin that matches the resin portion that satisfies the requirements of the above-mentioned formula (1) can be manufactured relatively freely. Therefore, the combination of the skin and the resin portion that satisfies the relationship between the above-mentioned formulas (1) and (2), i.e., the characteristics of the steering wheel, can be carefully designed, thereby completing the present invention.

[0072] When the grip portion of the steering wheel of this embodiment is gently gripped, there is no rebound like rubber, and a soft and gentle grip feeling as if the palm is sinking can be obtained. In addition, a reliable control feeling can be obtained, and the reliable control feeling refers to the feedback that the palm feels comprehensively from the state of gently placing both hands on the grip portion to the state of quickly gripping the grip portion, including a well-responsive reaction force and a grip feeling. As a specific example, when the steering wheel of this embodiment is a steering wheel for an automobile, for example, when the steering operation of the steering wheel is quickly alternating left and right for three times at a steering angle of 30°, a reliable control feeling can be obtained, in which the palm feels comprehensively the feedback including a well-responsive reaction force and a grip feeling.

[0073] [Steering wheel]

[0074] The steering wheel of the present invention will be described by taking a steering wheel used for an automobile as an example, but the steering wheel of the present invention is not limited to these examples.

[0075] Figure 1 , Figure 2 This is a plan view of an example of the steering wheel according to the present embodiment as seen from the driver's seat side.

[0076] Figure 1 , Figure 2 The steering wheel 1 shown in the figure has at least a rim portion (also called a handle portion) 10, a pad portion 11, and a spoke portion 12. The rim portion 10 is a portion that is gripped and rotated by the driver. The rim portion 10, the pad portion 11, and the spoke portion 12 may arbitrarily include components such as a decorative panel or a display panel.

[0077] Regarding the steering wheel 1 , the driver seat side is referred to as the front side, and the steering shaft (not shown) side attached to the steering wheel 1 is referred to as the back side. Figure 1 , Figure 2 It is a plan view of the steering wheel 1 as seen from the front side.

[0078] In addition, in the direction perpendicular to the rotation axis of the steering wheel 1, the direction in which the steering wheel 1 stands upright is referred to as the up-down direction. Figure 1 , Figure 2 The 0° direction shown is referred to as the upper direction, and the 180° direction is referred to as the lower direction. In addition, the 90° direction is referred to as the right direction, and the 270° direction is referred to as the left direction.

[0079] Figure 3 is a cross-sectional view of a rim portion of an example of a steering wheel according to the present embodiment, which corresponds to Figure 1 , Figure 2 A cross section of the steering wheel 1 obtained by observing the 0° position from the left direction to the right direction.

[0080] Figure 3 The rim portion 2 shown in the figure comprises at least a rim core portion 20, a resin portion 30 molded on the rim core portion 20, and a skin 40 covering the resin portion 30. The skin 40 may be formed on the rim core portion 20. Figure 3 Positions other than those shown have portions that are not covered with the resin portion 30. As long as the relationship between the above-mentioned equations (1) and (2) and the effects of the present invention are not excessively impaired, components such as temperature control mechanisms such as heaters and Peltier elements, sensor mechanisms such as piezoelectric elements, and information transmission mechanisms such as vibration elements can be arbitrarily provided between the resin portion 30 and the skin 40.

[0081] exist Figure 3In the rim portion 2 shown, the portions from 0° to 45° and from 315° to 360° are called outer peripheral portions, the portion from 135° to 225° is called inner peripheral portion, the portion from 45° to 135° is called front portion, and the portion from 225° to 315° is called back portion.

[0082] In the steering wheel of this embodiment, the cover can be provided only on the portion held by the driver. Figure 1 , Figure 2 The entire rim portion 10 shown in FIG. 1 may be provided only on a portion, or may be provided only on a portion of the rim portion 10. Figure 1 , Figure 2 The part from 45° to 90° and Figure 1 , Figure 2 In addition, for example, the epidermis may be provided at Figure 3 All of the outer peripheral portion, inner peripheral portion, front portion and back portion shown in the figure may be provided only in a portion continuous from the outer peripheral portion to the front portion, or may be provided in multiple non-continuous portions such as only the front portion and the back portion.

[0083] [shape]

[0084] The steering wheel of this embodiment is not limited to Figure 1 , Figure 2 Shape shown.

[0085] The shape of the rim portion of the steering wheel of this embodiment may be, for example, Figure 1 The circular shape, elliptical shape, rectangular shape, trapezoidal shape, and Figure 2 The wheel may be an annular shape such as a D-shaped shape in which a portion of the rim is composed of straight lines. In addition, the wheel may be a U-shaped or H-shaped shape in which a portion of the rim is not continuous around the wheel, such as a joystick of an airplane, and a rod-shaped shape with ends such as a non-annular I-shaped shape. It should be noted that in the case of an annular shape, generally, the maximum length in the width direction is taken as the diameter of the steering wheel regardless of the shape.

[0086] [Durometer hardness]

[0087] The steering wheel of the present embodiment satisfies the relationship of the following equations (1) and (2).

[0088] Formula (1): 0.65 ≤ G / L ≤ 0.95

[0089] Formula (2): 1.05 ≤ G / R ≤ 1.35

[0090] In other words, the numerical range of the ratio of G to L represented by formula (1) is 0.65 or more and 0.95 or less. In other words, the numerical range of the ratio of G to R represented by formula (2) is 1.05 or more and 1.35 or less.

[0091] In the above formula (1) and formula (2), L, R, and G have the following meanings.

[0092] L represents durometer hardness, which is the median of 10 measurements obtained by contacting a C-type durometer to the surface side of a piece of skin placed on a plate with a D-type durometer hardness of 80 or more. L is 10 or more and 100 or less.

[0093] R represents the durometer hardness, which is the median of 10 measurements obtained by contacting a C-type durometer to the surface of the resin portion molded on the rim core. R is 10 or more and 100 or less.

[0094] G represents the durometer hardness, which is the median of 10 measurements obtained by contacting a C-type durometer to the surface side of the skin in a state where the resin portion molded on the rim core is covered. G is 10 or more and 100 or less.

[0095] For L, R, and G, the "measurement" of contacting the C-type hardness meter is to contact the C-type hardness meter with the measurement object and immediately read the measurement value. In addition, for the "10 measurements" in the above "10 measurement values", (a) when the measurement site is the same, the next measurement is performed after an interval of more than 30 seconds; or (b) the nth measurement site and the n+1th measurement site are separated by more than 1 cm (n is an integer of 1 to 9); or (a) and (b) are combined.

[0096] When designing a steering wheel structure having a desired hardness measured by a static test, that is, a C-type durometer hardness G of the steering wheel surface, it is important to combine a skin that satisfies formula (1) and a resin portion that satisfies formula (2). By satisfying both formulas (1) and (2), it is expected that the balance that is the target in this embodiment, that is, the balance between the hardness of the steering wheel measured by a static test and the hardness of the steering wheel measured by a dynamic test, will be achieved. For this embodiment, it has a soft grip when lightly gripped, and a fatigue reduction effect during long-term driving operations can be expected, and it has a reliable sense of control and grip when holding it hard and performing intense operations such as in emergency evasion, and the most important correct and quick response can be expected. In this way, in this embodiment, by satisfying both formulas (1) and (2), a steering wheel that combines comfort and security can be provided.

[0097] For example, the value of G / L tends to decrease by increasing the C-type durometer hardness L of the surface, and tends to increase by decreasing the C-type durometer hardness L of the surface. By using this tendency to set the C-type durometer hardness L of the surface that satisfies formula (1), a surface suitable for obtaining a desired steering wheel hardness G can be selected.

[0098] For example, by increasing the C-type durometer hardness R of the resin portion, the G / R value tends to decrease, and by decreasing the C-type durometer hardness R of the resin portion, the G / R value tends to increase. By using this tendency to set the C-type durometer hardness R of the resin portion that satisfies formula (2), a resin portion suitable for obtaining a desired steering wheel hardness G can be selected.

[0099] The hardness G of the steering wheel can be set to a desired value by the manufacturer of the steering wheel according to the type and nature of the vehicle on which the steering wheel is mounted, and the characteristics and preferences of the main driver. On the other hand, based on the various grip strength levels assumed by the driver, from the perspective of the sense of reliability of the vehicle as a vehicle received by the operating device of the vehicle in a relaxed and lightly gripped state, G is preferably 50 or more, more preferably 53 or more. In addition, from the perspective of not easily causing excessive fatigue to the arms, shoulders, etc. even in a state of slightly tense and slightly strong gripping for a long time, a state requiring repeated manipulation, etc., G is preferably 90 or less, more preferably 85 or less.

[0100] In addition, based on various grip strength levels assumed by the driver, from the perspective of having a sufficient reaction force felt by the palm of the hand gripping and operating in a state where intense operation is required, such as in an emergency evasion, and a sense of security that an accurate and quick response can be expected, R is preferably 30 or more, more preferably 40 or more. In addition, from the perspective of being less likely to feel the above-mentioned tense state or excessive fatigue during long-term driving, R is preferably 75 or less, more preferably 72 or less.

[0101] From the viewpoint of the wear resistance of the surface of the skin, L is preferably 55 or more, more preferably 75 or more. From the viewpoint of the crack resistance of the surface of the skin, L is preferably 90 or less, more preferably 86 or less.

[0102] The relationship between the above-mentioned formulas (1) and (2) only needs to be satisfied on at least a part of the surface of the rim portion having the skin, and may be satisfied on the entire surface of the rim portion having the skin.

[0103] The relationship between the above equations (1) and (2) needs to be satisfied at least in the portion held by the driver (the gripping portion), and preferably also in other portions outside the gripping portion. Specifically, when the shape of the rim portion of the steering wheel is a circular shape, an elliptical shape, or a D-shaped shape, the relationship between the above equations (1) and (2) needs to be satisfied in the following portions: (a) Figure 1 , Figure 2 The portion from 60° to 90° and the portion from 270° to 300° of the rim portion 10 shown in FIG. 1 , or the portion from 90° to 120° and the portion from 240° to 270°; (b) Figure 3 The front part and / or the back part shown in . In addition, an example of a preferred embodiment is that the part other than (b) in the part (a), or the part of (b) in the part other than (a), and the part other than (b) in the part other than (a) also satisfies the relationship of the above-mentioned formulas (1) and (2).

[0104] [Rim core]

[0105] As long as the effect of the present invention is not impaired, the material constituting the rim core is not limited, and may be an alloy or a material other than an alloy. From the viewpoint of strength and durability of the steering wheel, the material constituting the rim core may include iron, aluminum, magnesium, or alloys thereof as suitable materials.

[0106] [Resin Department]

[0107] The resin portion is molded on the rim core portion.

[0108] The material constituting the resin portion is not limited as long as it satisfies the above-mentioned relational expressions (1) and (2), and a known material can be used.

[0109] The material constituting the resin portion specifically includes natural elastomers, synthetic elastomers, etc. Among them, from the viewpoint of the ease of selection of durometer hardness, the material constituting the resin portion is preferably a synthetic elastomer. As the synthetic elastomer, polyurethane elastomers, silicone elastomers, and fluorine elastomers are preferred, and ether polyurethane elastomers are more preferred. In addition, porous synthetic elastomers obtained by microfoaming these are further preferred.

[0110] For example, the resin portion can be molded on the rim core portion by the following operation.

[0111] A composition containing polyol, polyisocyanate, foaming agent and crosslinking agent is mixed by a high-pressure foaming machine. Then, the composition is injected into a mold with a rim core, and foamed and cured to form a resin blank of foamed polyurethane covering the rim core. At this time, the durometer hardness can be adjusted to a desired value by selecting raw material composition such as the hydroxyl value of the polyol, the injection amount into the mold, and molding conditions such as the temperature and time during foaming and curing.

[0112] [epidermis]

[0113] The skin covers at least a portion of the resin portion and is an artificial blank.

[0114] The appearance and touch of the epidermis can be leather-like, wood-like, wood-grain-like, metal-like, etc. In addition, for the epidermis, patterns, texts, symbols, etc. can be displayed on the entire surface or a part thereof by printing or molding. In the case of leather-like, the epidermis can imitate the appearance and touch of natural leather with suede, grain, etc. From the perspective of being preferred in the use of steering wheels, it is preferably a grain-like shape and a semi-grain-like shape in which a part of the surface is not a grain and a base (such as a fiber base material layer described later) is exposed. That is, the artificial blank is preferably a grain-like shape in which most of the surface is covered with grain.

[0115] The artificial blank is not limited as long as it satisfies the above-mentioned relational expressions (1) and (2), and any known material can be used.

[0116] Among them, from the viewpoint of easy selection of durometer hardness, the artificial blank is preferably a laminate (sheet) including a fiber base material layer and a resin coating layer.

[0117] The thickness of the sheet may be, for example, approximately 0.5 to 2.0 mm, and is preferably in the range of 0.8 to 1.8 mm from the viewpoint of easily obtaining a durometer hardness L in a suitable range in the present embodiment.

[0118] Examples of the fibrous raw material constituting the fiber base material layer include woven fabrics, knitted fabrics or nonwoven fabrics containing one or more synthetic fibers selected from amide resins, acrylic resins and ester resins; natural fibers such as cotton and linen; and regenerated fibers such as rayon and cuprammonia.

[0119] However, the fabric is not good at following the curved shape, and the skin is often bent or wrinkled near the curved part. In addition, the knitted fabric is easy to stretch compared with the woven fabric, so the resin coating layer is easy to partially warp or peel due to the difference in the stretching mode of the resin coating layer. In the case of a steering wheel that is given a high-end and designed feeling by covering most of the outer surface with a soft skin without using a panel or molding, if the fiber base material layer is a woven fabric or a knitted fabric, the above properties cannot fully adapt to the entire shape of the part covered by the skin, and it is not suitable as a skin. Compared with woven fabrics and knitted fabrics, since the anisotropy of elongation is small due to the dense structure, excessive elongation can be suppressed, it is not easy to bend, or the bonding part with the resin coating layer is not easy to peel or warp, so non-woven fabrics are preferred. In addition to non-woven fabrics, even knitted fabrics can make the above problems less likely to occur by selecting a woven structure. From this point of view, warp knits such as warp knitted fabrics and raschel fabrics that can suppress unnecessary elongation through a dense woven structure are also preferred. That is, warp knit is more preferable than weft knit such as circular knitted fabric and rubber knitted fabric having a loose knitting structure.

[0120] The average fiber diameter of the fibrous blank may be, for example, about 10 μm or less. From the viewpoint of workability during rim coating, aesthetics such as surface smoothness after coating, and gripping feeling described below, the average fiber diameter of the fibrous blank is preferably 0.1 to 6 μm.

[0121] The fiber base material layer is preferably a fibrous blank with a resin, and nonwoven fabric is preferably used in the fibrous blank. That is, the fiber base material layer is preferably a nonwoven fabric with a resin. Nonwoven fabric has a lower apparent density and more space than woven fabrics and knitted fabrics, so it can be given resin at a higher density.

[0122] The nonwoven fabric endowed with resin can easily change the ratio of fiber to resin and the apparent density of the fiber base layer. In addition, when used as the surface of a steering wheel, the resin is not easily damaged or shed in the fiber base layer. In addition, the durometer hardness of the above-mentioned surface can be easily adjusted.

[0123] Methods for obtaining a nonwoven fabric with a resin include, for example, a method of impregnating the nonwoven fabric with a resin and a method of applying a resin to the back of the nonwoven fabric. For nonwoven fabrics, by adjusting the apparent density and the degree of cohesion, a desired fiber structure can be designed, and a fiber structure that is easy to impregnate the resin into can be selected.

[0124] In the above nonwoven fabric to which the resin is applied, examples of the resin include urethane resins, acrylic resins, ester resins, vinyl chloride resins, etc. These resins may be used alone or in combination of two or more.

[0125] In the nonwoven fabric to which the resin is applied, the ratio of the nonwoven fabric to the resin [nonwoven fabric / resin] can be about 30 / 70 to 95 / 5 in terms of mass ratio.

[0126] In order to adjust the durometer hardness, the resin is preferably a composition containing fine particles.

[0127] Examples of the fine particles include talc, magnesium silicate, calcium sulfate, aluminum silicate, calcium carbonate, magnesium oxide, magnesium carbonate, metal hydroxides such as magnesium hydroxide and aluminum hydroxide, and mica, etc. The fine particles may be used alone or in combination of two or more.

[0128] Furthermore, from the viewpoint of increasing the durometer hardness and imparting flexibility and appropriate elongation to the fiber base material layer, the Mohs hardness of the microparticles is preferably 1.5 or more, more preferably 2 or more and 9 or less.

[0129] The ratio of resin to microparticles [resin / microparticles] can be selected in the range of about 5 / 95 to 95 / 5 in terms of mass ratio, and is preferably in the range of about 15 / 85 to 60 / 40 in order to significantly obtain the effect of adding microparticles.

[0130] As the resin blank constituting the resin coating layer, for example, urethane resin and vinyl chloride resin can be used. In addition, from the viewpoint of the ease of selection of the durometer hardness, the resin coating layer is preferably non-porous or less foamed. It should be noted that in the present embodiment, the above-mentioned "less foamed state" means that when a cross-section is observed, even if there is foaming, it is sparsely present in a size of less than half the thickness of the resin coating layer.

[0131] In order to obtain a durometer hardness L within a suitable range in the present embodiment, the thickness of the resin coating layer may be, for example, about 0.08 to 0.5 mm, and is preferably within a range of 0.1 to 0.4 mm in terms of balance with the fiber base layer to be laminated.

[0132] Compared with 1 layer, the resin coating is preferably composed of more than 2 layers. If it is a composition of more than 2 layers, then for the epidermis, the first layer of the most surface side can contain a large number of water- and oil-repellent agents such as colorants, fluororesins, silicone resins, etc., substantially without colorants and containing a large number of functional agents such as flame retardants, aromatics, etc. after the second layer, in addition, it is also possible to simultaneously obtain sufficient bonding force for the fiber substrate layer with concavoconvexity and the smoothness of the surface of the epidermis, and become the epidermis with high-quality appearance and high-function concurrently. The thickness of the first layer is preferably the scope of 0.02~0.3mm, and the total thickness after the second layer is preferably the scope of 0.06~0.4mm. For example, in order to contain a large number of functional agents, as long as the total thickness after the second layer is made thicker than the first layer within the scope of the thickness of the above-mentioned resin coating, in order to contain a large number of pigments, water- and oil-repellent agents, as long as the first layer is made thicker than the total thickness after the second layer within the scope of the thickness of the above-mentioned resin coating.

[0133] The method of laminating the resin coating layer on the fiber substrate layer includes, for example, a method of directly coating the fiber substrate layer with resin; and a method of pre-coating the resin on a release sheet that transfers the surface appearance and unevenness similar to natural leather, wood grain, etc. to the surface of the resin coating layer, and then laminating the resin on the fiber substrate layer. A representative example of the release sheet is release paper. Commercially available release paper can be used.

[0134] Examples of the above-mentioned resin coating include dry coating and wet coating. Dry coating is a resin coating in which the solvent and dispersant are volatilized from the applied resin solution or resin dispersion to solidify and dry the resin. Wet coating is a resin coating in which the applied resin solution is solidified by contacting a solidifying liquid such as by dipping or spraying, and then the residual solvent and solidifying liquid are replaced and dried. The solidifying liquid is a good solvent for the solvent in the resin solution and a poor solvent for the resin.

[0135] In this embodiment, the combination of any of the above-mentioned lamination methods and resin coating can be appropriately selected according to the target surface design. In the surface design and production of this embodiment, a method of preparing a resin coating layer using at least a release sheet (release paper) and attaching it to a fiber base material layer, and a combination of any method using dry coating are suitable, and the most preferred is their combination.

[0136] In order to give the surface feel, fine-tuning of the appearance and antibacterial properties to the epidermis, a surface treatment coating layer can be further provided on the surface side of the resin coating layer. The type of surface treatment agent can be selected according to the purpose. It is preferred to use a surface treatment agent that is mainly composed of the same type of resin as the resin coating layer and contains pigments, fillers and antibacterial agents according to the purpose. It is preferred to directly apply the surface treatment agent to the surface of the resin coating layer by gravure coating, screen coating and the like. In particular, from the perspective of obtaining a homogeneous and smooth appearance and feel, the amount of the surface treatment agent is preferably 50 g / m 2 in terms of solid content. 2 The thickness of the surface treatment coating layer is preferably 0.03 mm or less.

[0137] In addition, from the perspective of the ease of operation of the steering wheel manufacturing described later, the appearance of the obtained steering wheel, the smoothness of the hand feel, and other qualities, it is preferred to apply resin to the back side of the fiber base material layer that does not have the resin coating layer. The resin blank and the coating method are the same as those of the above-mentioned resin coating layer.

[0138] As an example of an embodiment, for example, the grain artificial leather disclosed in International Publication No. 2018 / 221301 can be used as an artificial raw material.

[0139] The method of covering the resin portion with the skin can be performed, for example, by winding the skin around at least a portion of the resin portion and bonding the edge portions of the skin that are adjacent to each other with a sewing thread or the like.

[0140] For the epidermis, when the direction in which the 5% tensile strength is the highest is set to be consistent with the direction from the front side to the back side of the steering wheel and is wound around the resin part, not only is the process from winding the epidermis around the resin part to the bonding of the end edges easy to operate, but also the hardness G of the steering wheel can be stably obtained regardless of the measurement position by the combination of the epidermis and the resin part that satisfies the formula (1) and formula (2) of the present embodiment. It should be noted that the above-mentioned "consistent direction" refers to an angle range of about plus or minus 15 degrees. That is, the direction in which the 5% tensile strength of the epidermis is the highest is preferably consistent with the direction from the front side to the back side.

[0141] In addition, as long as the effect of the present invention is not impaired, a bonding layer such as an adhesive or adhesive tape may be sandwiched between the resin portion and the skin. In the case of sandwiching a bonding layer, the skin and the resin portion are not directly bonded. That is, a mode in which at least a portion of the skin is not bonded to the surface of the resin portion is also one of the present embodiments.

[0142] Adhesives and adhesive tapes generally used in the art can be used. The laminating layer can be provided on the entire resin portion to which the epidermis is to be laminated. From the perspective of the epidermis winding process in steering wheel manufacturing, the ease of operation in the bonding process of bringing the epidermis ends close to each other or sewing them, and the quality of the appearance and smooth feel of the resulting steering wheel, it is preferably provided only on a portion of the resin portion. Specifically, it is preferred that the laminating layer is not provided on the outer periphery of the steering wheel, but is provided only on the front side of the steering wheel, or is provided only on the front side and the back side. It is also preferred that the laminating layer contain a function-imparting agent such as a flame retardant. In this case, it is also preferred to enlarge the laminating layer portion according to the amount of the functional agent to be imparted, and set it to an area close to the entire surface of the resin portion.

[0143] In addition, regarding the adhesive strength, it is not necessary to have such a strength that the surface skin and the resin part are damaged when peeling is attempted, and from the viewpoint of ease of operation, the average peel strength per 1 cm width is preferably 10 N or more on average. On the other hand, from the viewpoint of obtaining the effects of the steering wheel of this embodiment including the gripping feeling, it is preferably in the range of about 15 to 100 N on average.

[0144] [use]

[0145] The steering wheel of this embodiment is a control device of a vehicle, and is suitable for use in a structure that requires at least a portion that the driver holds with his or her left and right hands for control. In this specification, a vehicle is a general term for a tool that carries or moves people, objects, etc. arbitrarily except for the driver. Examples of vehicles include trains, trams, cars, ships, airplanes, etc.

[0146] Example

[0147] Hereinafter, the present invention will be specifically described by way of Examples and Comparative Examples, but the present invention is not limited to these Examples.

[0148] [Examples 1 to 4] [Comparative Examples 1 to 4]

[0149] A material is prepared in which a resin portion formed of a foamed body of an ether-based polyurethane elastomer is molded around an annular rim core metal. Next, the entire resin portion is covered with the following artificial blank (sheet) which is a laminated body including a fiber base material layer and a resin coating layer, such as Figure 3 The surface was set as shown, and a 36 cm diameter was produced. Figure 1 The steering wheel shown in FIG. 36 is a diameter of the steering wheel selected from a range of 34.5 to 37.5 cm. It should be noted that when the resin portion is covered with the skin, the fiber base material layer is arranged so as to face the resin portion.

[0150] The specific structure and manufacturing method of the artificial blank used in the examples and comparative examples are as follows.

[0151] <Example 1>

[0152] The fiber substrate layer was prepared as follows. A PU solution containing microparticles at a ratio of polyether polyurethane (PU) / microparticles [metal hydroxide, Mohs hardness 3, average particle size 3 μm] = 20 / 80 (mass ratio) was impregnated into an ultrafine fiber nonwoven fabric of nylon fibers having an average fiber diameter of 1.3 μm, immersed in water, wet coagulated, and dried, thereby preparing a fiber substrate layer in which polyether PU and microparticles were imparted inside the ultrafine fiber nonwoven fabric. The thickness of the fiber substrate layer was 1.2 mm.

[0153] Next, a resin coating layer was prepared as follows and bonded to the fiber base material layer to produce an artificial blank.

[0154] The resin coating layer was prepared as follows. First, a polycarbonate / polyester high-solid PU liquid (solid content 75% by mass, the same below) was prepared. Then, it was applied to a release sheet that can give a natural leather-like appearance (release paper "DN-TP (registered trademark) DE-145" manufactured by Dai Nippon Printing Co., Ltd.), dried, and a 40μm surface layer of the first layer was formed. Next, a 200μm intermediate layer was formed on the first layer in the same manner as the second layer using a polyester high-solid PU liquid to which a flame retardant was added. Furthermore, a polyester PU adhesive liquid to which a flame retardant and a cross-linking agent were added was applied on the second layer as the third layer, so that the layer thickness of the third layer after bonding with the above-mentioned fiber base material layer reached 80μm. Thus, a resin coating layer formed by three layers was prepared.

[0155] After it was semi-dried, the third layer was attached to the fiber substrate layer and fully cross-linked with a cross-linking agent at 60°C to make them adhere. Then, the release sheet (release paper) was peeled off. Finally, a polycarbonate / polyester PU aqueous dispersion was gravure coated on the obtained laminate so that the solid content reached 50 g / m 2 Thus, a polycarbonate / polyester PU surface treatment coating layer is formed on the surface of the first layer which is given a natural leather-like appearance.

[0156] Thus, an artificial blank is produced.

[0157] <Example 2, Comparative Example 4>

[0158] In Example 1, the same artificial blank was produced except that the polycarbonate / polyester-based PU surface treatment coating layer was not provided on the resin coating layer.

[0159] <Example 3, Comparative Example 2, Comparative Example 3>

[0160] As the fiber base layer, the same fiber base layer as in Example 1 (containing no fine particles) was used.

[0161] The resin coating layer was prepared as follows. First, a polycarbonate / polyester PU solution was prepared. Then, it was applied to a release sheet (the release paper manufactured by the aforementioned Dai Nippon Printing Co., Ltd.) and dried to form a 20 μm epidermal layer of the first layer. Next, a polyester PU adhesive solution to which a crosslinking agent was added was applied on the first layer as the second layer so that the layer thickness of the second layer after being bonded to the fiber base layer reached 60 μm. Thus, a resin coating layer formed of two layers was prepared.

[0162] After it was semi-dried, the second layer was attached to the fiber base layer, and crosslinking was fully performed at 60°C using a crosslinking agent to make them adhere. Then, the release sheet (release paper) was peeled off. Finally, the same polycarbonate / polyester PU surface treatment coating layer as in Example 1 was provided on the surface of the side (first layer) that was given a natural leather-like appearance. Thus, an artificial blank was manufactured.

[0163] <Example 4>

[0164] In Example 1, the same artificial blank was produced except that the thickness of the high solid coating portion in the resin coating layer was changed (170 μm for the first surface layer and 100 μm for the third layer after bonding with the fiber base layer).

[0165] <Comparative Example 1>

[0166] As the fiber base layer, a fiber base layer obtained by impregnating the same polyether PU solution (containing no microparticles) as in Example 1 into the same ultrafine fiber nonwoven fabric as in Example 1, further coating the same polyether PU solution (containing no microparticles) as in Example 1 on one side of the ultrafine fiber nonwoven fabric, wet coagulating and drying was used. The thickness of the fiber base layer was 1.1 mm, the polyether PU was applied inside the ultrafine fiber nonwoven fabric, and the wet coating layer on the surface of the ultrafine fiber nonwoven fabric was 30 μm.

[0167] The resin coating layer was prepared as follows. First, a polycarbonate / polyester PU solution was prepared. Then, it was applied to a release sheet (the release paper manufactured by the aforementioned Dai Nippon Printing Co., Ltd.) that can give a natural leather-like appearance, immersed in water, thereby wet coagulation and drying to form an 80μm epidermal layer of the first layer. Next, a polyester PU adhesive liquid with a flame retardant and a cross-linking agent added thereto, which is the same as the polyester PU adhesive used in the third layer of Example 1, was applied on the first layer as the second layer, so that the layer thickness of the second layer after being bonded to the fiber base material layer reached 30μm. Thus, a resin coating layer formed by two layers was prepared.

[0168] After it was semi-dried, the second layer was attached to the wet-coated surface of the fiber base material layer, and crosslinking was fully performed at 60°C using a crosslinking agent to make it adhere. Then, the release sheet (release paper) was peeled off. Finally, the same polycarbonate / polyester PU surface treatment coating layer as in Example 1 was provided on the surface of the resin coating layer (the side in contact with the release paper) after the release sheet (release paper) was peeled off. Thus, an artificial blank was manufactured.

[0169] The artificial blank used in Comparative Example 1 was significantly inferior to that in Example 1 in wear resistance (JIS K 7204-1999 Taber wear test, load 4.9 N, wear wheel H22).

[0170] In addition, the resin portion constituting the steering wheel obtained in each of the examples and comparative examples was used after adjusting the C-type durometer hardness (Asker C hardness) to the value R shown in Table 1.

[0171] [Asker C hardness]

[0172] The C-type durometer hardnesses L, R, and G were measured by the following measurement method in accordance with JIS K 7312-1996.

[0173] R and G are measured at the grip part of the steering wheel, that is, Figure 1 The ranges from 60° to 120° (hereinafter referred to as “right”) and from 240° to 300° (hereinafter referred to as “left”) are shown in FIG. Figure 3 The angle can be adjusted at any position of the front portion covered by the epidermis within the range of 45° to 135° as shown.

[0174] <G> For the steering wheels manufactured in each embodiment and comparative example, first, a C-type hardness tester was brought into contact with any part of the grip portion (two parts on the left and right), and the left and right parts were measured 5 times each, for a total of 10 times. In this measurement method, the same part was measured at an interval of more than 30 seconds from the previous measurement.

[0175] <L> Next, the epidermis (two left and right parts) including the measurement part of G was peeled off. For the peeled epidermis, L was measured near the measurement part of G. The measurement of L was as follows: on a smooth flat plate with a D-type durometer hardness of 85, the epidermis was spread with the surface side facing upward, and after more than 5 minutes from the measurement of G, a C-type durometer was brought into contact with the vicinity corresponding to the measurement part of G, and the left and right parts were measured 5 times each, for a total of 10 times. The measurement method is the same as above.

[0176] <R> Finally, R was measured near the surface of the resin portion after the skin was peeled off, corresponding to the G measurement site. R was measured as follows: after 5 minutes or more from the measurement of G, a C-type hardness tester was brought into contact with the vicinity corresponding to the G measurement site, and the left and right sides were measured 5 times each, for a total of 10 times. The measurement method is the same as above.

[0177] The measured values ​​of G, L, and R were all the medians of 10 measurements, 5 for each side.

[0178] [evaluate]

[0179] The steering wheels obtained in the examples and comparative examples were held with both hands. Figure 1 The grip, handling and their comprehensive evaluation were evaluated in the range of 60° to 120° and 240° to 300° (grip portion) shown below according to the following evaluation criteria. The grip and handling evaluations were performed using the median of the evaluations of 13 reviewers aged 30 to 50 who were accustomed to driving a car. The comprehensive evaluation value was obtained by adding the grip score and the handling score.

[0180] ≪Grip≫

[0181] The grip feeling was defined as “the hardness felt by the palms when lightly gripping the grip portion with both hands”.

[0182] 5: Clearly feel the softness and feel the palm sinking deeply.

[0183] 4: I didn't feel any rubber-like rebound, but I could feel my palm sinking into the surface.

[0184] 3: I didn't feel any rebound like rubber, but I felt it sink into the body, albeit very slightly.

[0185] 2: Feel the strong rebound like the rubber of a tire.

[0186] 1: Feels as hard as wood.

[0187] ≪Control Feel≫

[0188] As a preliminary preparation for the evaluation, a steering wheel was installed. Specifically, a steering wheel was mounted on a steering shaft that generates torque only by friction, and the torque was set to generate a force required to rotate the steering wheel of 27.7N±0.3N.

[0189] The steering feel is defined as "the comprehensive feedback felt when the steering operation is performed from the neutral position to a steering angle of 30°, from the state of lightly placing both hands on the grip to quickly gripping, alternating at about 0.20 to 0.35 Hz for three times each."

[0190] 3: I feel the extremely responsive reaction force to the steering operation and feel very reliable feedback.

[0191] 2: Feel the reaction force that responds well to the steering operation and feel reliable feedback.

[0192] 1: The response to steering operations feels slow and the feedback is unreliable.

[0193]

[0194] The steering wheel of the embodiment satisfies the relationship between equations (1) and (2), and the comprehensive evaluation of the grip and the steering feel is greater than 5. On the other hand, the steering wheel of the comparative example does not satisfy the relationship between both or either of equations (1) and (2), and the comprehensive evaluation of the grip and the steering feel is less than 4.

[0195] Therefore, it can be seen that the steering wheel of the present embodiment has a soft grip feeling when lightly gripped and a reliable control feeling when firmly gripped by satisfying the relationship between equations (1) and (2).

[0196] Even if the diameter of the steering wheel is changed within the range of 34.5 to 37.5 cm, and even if the shape of the steering wheel is changed to an elliptical shape or a D-shape, the grip portion can be configured in the same manner as the steering wheel of the above-mentioned embodiment, and therefore, it can be expected that the same evaluation results as those of the above-mentioned embodiment can be obtained.

[0197] When the resin part is covered with a skin, even if the scope of the skin covering is limited to the gripping part instead of the entire resin part, since the ungripped part does not involve the gripping feel and the operating feel, it can of course be expected that the same evaluation results as the above-mentioned embodiment can be obtained.

[0198] Industrial Applicability

[0199] The steering wheel of this embodiment is an operating device for vehicles such as trains, trams, cars, ships, and airplanes, and can be used for applications requiring a structure having at least portions that a driver holds with his or her left and right hands for steering.

Claims

1. A steering wheel comprising: Rim core, a resin portion molded on the rim core portion, and a skin covering at least a portion of the surface of the resin portion, The skin is an artificial blank. The steering wheel satisfies the following relationship between equations (1) and (2): Formula (1): 0.65 ≤ G / L ≤ 0.95 Formula (2): 1.05 ≤ G / R ≤ 1.35 L represents the durometer hardness, which is the median of 10 measurements obtained by contacting the surface side of one sheet of the epidermis with a C-type durometer placed on a flat plate having a D-type durometer hardness of 80 or more, wherein: L is 10 or more and 100 or less, R represents a durometer hardness, which is a median of 10 measurements obtained by contacting a C-type durometer to the surface of the resin portion molded on the rim core, wherein R is greater than or equal to 10 and less than or equal to 100. The G represents a durometer hardness, which is measured by bringing a C-type durometer into contact with the surface side of the skin in a state where the surface of the resin portion molded on the rim core is covered, and the median value is obtained from 10 measurement values, wherein G is greater than or equal to 10 and less than or equal to 100.

2. The steering wheel according to claim 1, wherein: The G is greater than or equal to 50 and less than or equal to 90.

3. The steering wheel according to claim 1 or 2, wherein: The R is 75 or less.

4. The steering wheel according to any one of claims 1 to 3, wherein: The L is 90 or less.

5. The steering wheel according to any one of claims 1 to 4, wherein: The L is 75 or more.

6. The steering wheel according to any one of claims 1 to 5, wherein: The artificial blank is in a grain shape.

7. The steering wheel according to any one of claims 1 to 6, wherein: The artificial blank is a laminate including a fiber base material layer and a resin coating layer.

8. The steering wheel according to claim 7, wherein: The fiber base material layer is a nonwoven fabric to which a resin is applied.

9. The steering wheel according to any one of claims 1 to 8, wherein: At least a portion of the skin is not bonded to the surface of the resin portion.

Images