How to design the front shape of a headrest

Abstract

An example of a design method for determining the front shape of a headrest is disclosed. [Solution] A curve passing through points A, B, and C is determined, and a curved surface including this curve is used as the front shape of headrest 1. Point A is a position obtained by shifting point B downward by a predetermined distance along the headrest's displacement direction, point B is a position shifted rearward by the standard backset dimension from the position of the back of the head based on the hip point in a whiplash evaluation position with a torso angle of 25°, and point C is the point of contact between the S line and the head of an AM50 dummy when the head is tilted rearward around C7 with a torso angle of 21°.

Description

[Technical Field]

[0001] The present disclosure relates to a design method for determining the front shape of a headrest for a vehicle seat. [Background technology]

[0002] For example, Patent Document 1 discloses a headrest stay that takes whiplash protection into consideration. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2023-69084 Summary of the Invention [Problem to be solved by the invention]

[0004] Currently, the front shape of a headrest that can ensure good whiplash protection is determined by trial and error. The present disclosure discloses an example of a method for designing the front shape of a headrest in consideration of this point. [Means for solving the problem]

[0005] A design method for determining the front shape of a headrest for a vehicle seat is, for example, as follows. That is, in a whiplash evaluation position with a torso angle of 25°, the position shifted rearward by the standard backset dimension from the position of the back of the head based on the hip point is defined as Point B, and the position shifted downward by a predetermined dimension in the direction of headrest displacement is defined as Point A, and in a whiplash evaluation position with a torso angle of 21°, the vertical line passing through the position shifted rearward by the standard backset dimension from the position of the back of the head based on the hip point is defined as Line S, and when the head of the AM50 dummy is tilted rearward around C7 at a torso angle of 21°, the point of contact between Line S and the head is defined as Point C, and it is desirable to determine a curve passing through Points A, B, and C, and to use the curved surface including this curve as the front shape of the headrest.

[0006] As a result, this method makes it possible to obtain a headrest front shape that can ensure good whiplash protection. Incidentally, the symbols in each of the parentheses above are examples showing the correspondence with the specific configurations, etc. described in the embodiments described below, and the present disclosure is not limited to the specific configurations, etc. shown by the symbols in the parentheses above. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 2 is a view showing a headrest and a seat back. [Figure 2] FIG. 1 is an explanatory diagram of a design method. [Figure 3] FIG. 1 is an explanatory diagram of a design method. [Figure 4] FIG. 1 is an explanatory diagram of a design method. [Figure 5] FIG. 1 is an explanatory diagram of a design method. [Figure 6] 10 is a graph showing the results of a sensory evaluation of a headrest designed using the design method. DETAILED DESCRIPTION OF THE INVENTION

[0008] The following "embodiments of the invention" are examples of embodiments that fall within the technical scope of the present disclosure. In other words, the invention-specific matters described in the claims are not limited to the specific numerical values, configurations, etc. shown in the following embodiments.

[0009] This embodiment is an example in which the method for designing the front shape of a headrest (hereinafter abbreviated as design method) according to the present disclosure is applied to a seat (hereinafter referred to as a vehicle seat) to be mounted on a vehicle such as a car.

[0010] As shown in Fig. 1, the headrest 1 is attached to the upper end of the seat back 2 to support the back of the seated occupant's head. The seat back 2 supports the back of the seated occupant. The headrest 1 is attached to the seat back 2 so as to be displaceable in the up and down direction.

[0011] Hereinafter, when the headrest 1 is at its lowest position, it will be referred to as "the headrest 1 is in the lowest position." When the headrest 1 is in the midpoint position in the displacement direction, it will be referred to as "the headrest 1 is in the middle position."

[0012] The terms used in the following explanation are defined in the Global Technical Regulations (GTR) unless otherwise specified. Therefore, detailed explanations of terms defined in the GTR will be omitted in the following explanation.

[0013] (First embodiment) <1. Overview of the design method> In this specification, the front shape of the headrest 1 refers to the front edge of the cross section of the headrest 1 at the center in the seat width direction, perpendicular to the width direction, that is, the shape of the thick two-dot chain line in FIG.

[0014] First, the designer (including the design computer system) determines Point B, which is located at the whiplash evaluation position with a torso angle of 25° and is shifted rearward by the standard backset dimension from the position of the occipital region relative to the hip point (see Figure 2).

[0015] Next, the designer determines point A by shifting point B downward by a predetermined distance along the displacement direction of headrest 1 (see Figure 2). Note that this "predetermined distance" refers to the difference between the "position of headrest 1 when headrest 1 is located in the central position" and the "position of headrest 1 when headrest 1 is located in the lowest position."

[0016] Next, the designer determines the S-line as a vertical line passing through a position shifted rearward by the standard backset dimension from the position of the back of the head based on the hip point in the whiplash evaluation position with a torso angle of 21° (see Figure 3).

[0017] Next, the designer sets the torso angle at 21° and tilts the head of the AM50 dummy backward around C7, determining the point of contact between the S-line and the head as point C (see Figure 4). The AM50 dummy is a mannequin that is 50% (average) of the size of an American adult male. C7 refers to the seventh cervical vertebra from the top, i.e., the seventh cervical vertebra.

[0018] Finally, the designer determines a curve (for example, a spline curve) that passes through points A, B, and C, and defines a curved surface including this curve as the front shape of headrest 1 (see Figure 5). Point A is the position on the front surface of headrest 11 that is shifted horizontally backward from the back of the head when headrest 1 is in the central position.

[0019] Points B and C are positions on the front surface of the headrest 1 when the headrest 1 is in the lowest position. In particular, point B is a position on the front surface of the headrest 11 that is shifted horizontally backward from the back of the head when the headrest 1 is in the lowest position.

[0020] <2. Specific Examples> In this embodiment, point B is determined, for example, as follows: Note that the numerical values ​​such as "504.5" and "203" shown in the following formula are specific values ​​that comply with the above-mentioned international technical regulations.

[0021] H coordinate=504.5×cos(25-2.6)+203...Equation 1 The H coordinate refers to a vertical coordinate with the hip point as the reference point (origin). L coordinate=504.5×sin(25-2.6)+71+35...Equation 2 The L coordinate refers to the coordinate in the front-to-rear direction of the seat, with the hip point as the reference point (origin).

[0022] It should be noted that "35" in Equation 2 is the value of the standard backset dimension according to this embodiment. The H coordinate and L coordinate values ​​for "the position shifted rearward by the standard backset dimension from the position of the occipital region based on the hip point in a whiplash evaluation position with a torso angle of 21°" are calculated using the following Equations 3 and 4.

[0023] H coordinate=504.5×cos(21-2.6)+203...Equation 3 L coordinate=504.5×sin(21-2.6)+71+35...Equation 4 3. Features of the design method according to this embodiment 6, the graph indicated by line A is a graph showing the results of the sensory evaluation of the headrest 1 designed by the above design method. As is clear from the sensory evaluation results, even if there are differences in the physiques of seated persons, good evaluation results can be obtained by using the headrest 1 designed by the above design method.

[0024] (Other embodiments) In the above-described embodiment, the vehicle seat according to the present disclosure is applied to a vehicle. However, the application of the invention disclosed in this specification is not limited thereto. That is, the present disclosure can also be applied to seats used in vehicles such as railway cars, ships, and aircraft, as well as stationary seats used in theaters, homes, etc.

[0025] Furthermore, the present disclosure is not limited to the above-described embodiments as long as it conforms to the spirit of the disclosure described in the above-described embodiments. Therefore, the present disclosure may be a configuration in which at least two of the above-described embodiments are combined, or a configuration in which any of the components illustrated or described with reference numerals in the above-described embodiments is eliminated. [Explanation of symbols]

[0026] 1. Headrest 2... Seat back

Claims

1. A design method for determining a front shape of a headrest for a vehicle seat, comprising: In the whiplash evaluation position with a torso angle of 25°, the position shifted backward by the standard backset dimension from the position of the occipital region based on the hip point is defined as point B. Point A is a position obtained by shifting point B downward by a predetermined distance along the displacement direction of the headrest, In the whiplash evaluation position with a torso angle of 21°, the vertical line passing through a position shifted backward by the standard backset dimension from the position of the occipital region based on the hip point is defined as the S line. With the torso angle at 21°, the point of contact between the S line and the head when the head of the AM50 dummy is tilted backward around C7 is defined as point C. A method for designing the front shape of a headrest by determining a curve that passes through point A, point B, and point C, and defining a curved surface including the curve as the front shape of the headrest.

2. Point A is a position on the front surface of the headrest when the headrest is positioned in the center position, 2. The method for designing the front shape of a headrest according to claim 1, wherein the point B and the point C are positions on the front surface of the headrest when the headrest is located at the lowermost position.

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