JP2918443B2 - S spring for vehicle seat - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an S-spring for a vehicle seat, and more particularly, to an S-spring for a vehicle, truck or the like, which is incorporated into a vehicle seat for the purpose of imparting shape resilience and cushioning. It relates to the S spring.

[0002]

2. Description of the Related Art As shown in FIG. 4A, a seat (1) for a passenger car or a truck has a pad (3) made of a foamable resin, for example, urethane foam inside a trim cover (2) made of fabric or leather. ), And an S-spring (5) stretched on a seat frame (4) made of a spring material such as a hard steel wire is further disposed inside, thereby restoring shape and cushioning to balance the seating load P. Is given.

[0003] The S spring (5) is formed of a spring wire rod meandering along a plane substantially perpendicular to the load direction of the seating load P, as enlarged and shown in Fig. 4 (B). A conventional S-spring (5) supplies a spring material such as a hard steel wire having a circular cross section to a bending device (not shown), and bends it to have a predetermined pitch and amplitude, thereby forming an S-shaped meander. The biasing member is capable of being repeatedly elastically deformed. Both ends of the S spring (5) are clipped (6) inside the pad (3).
To the seat frame (4).

On the other hand, the seat frame (4) has the S
In addition to the spring (5), when a seating load P is applied, it is elastically deformed in a direction substantially perpendicular to the meandering surface of the S spring (5), and is an auxiliary for correcting the load bending characteristic of the S spring (5). A cup spring (7) having an inverted truncated conical coil shape is also attached as a biasing member.

[0005]

Since the conventional S spring (5) is formed from a hard steel wire having a circular cross section, a load / deflection diagram when a seating load P is applied is shown in FIG. As shown by the symbol B, the curve becomes a rising slope with a relatively gentle slope.

When the gradient of the load / deflection curve changes from the load starting point P ₀ of the seating load P to the final load point P ₁ while maintaining a relatively gentle gradient, the seating load P increases. Since the change in the deflection S corresponding to the above is set to a low value, an uncomfortable feeling is easily generated when the user sits on the seat (1). Further, in the case of the S spring having a circular cross-section, when the seat is seated, a line contact is made, so that a sense of discomfort is large.

In order to eliminate the above-mentioned uncomfortable feeling, it is necessary to increase the thickness of the pad (3) to be filled in the trim cover (2), which hinders the weight reduction of the seat (1) and reduces the production cost. Get higher.

Further, conventional S springs fabricated from a wire having a circular cross-section (5) is relatively flat in the region up to the intermediate load point Pm load-deflection characteristics from the load starting point P ₀ of the seating load P to vary Egai the a curve in the vicinity of the final applied load point P ₁ not sufficient cushioning Conversely, the impact becomes large at the time of seating.

[0009] In other words, S load-deflection characteristics of the spring (5), the intermediate load point Pm from the load starting point P ₀ of the seating load P
Up is relatively gentle slope of the load-deflection diagram, in the vicinity of the final applied load point P ₁ is preferably set such that the gradient increases rapidly.

[0010] However, when using the S spring (5) of the conventional type comprising a wire having a circular cross-section, from the load starting point P ₀ up to the final weight load point P _1, is gradual load-deflection characteristics right shoulder Since the upward slope is maintained, the deflection amount S
Vicinity of the final applied load point P ₁ but with the maximum, i.e., in the vicinity of elastic limit, cushioning property is insufficient to reverse impact increases at the time of seating.

In order to solve this problem, in addition to the S-spring (5) made of a spring wire having the above-mentioned circular cross section inside the seat (1), an inverted truncated conical coil shape is used as an auxiliary biasing member. It is necessary to incorporate the cup spring (7) provided, and the number of components of the seat (1) increases by that much, the structure of the seat (1) becomes complicated, and the number of assembling steps also increases. As a result, the manufacturing cost of the sheet (1) rises.

[0012]

According to the present invention, there is provided an S-spring which stretches a seat frame built in a vehicle seat to impart elasticity to the seat spring in a direction substantially corresponding to a load direction of a seating load. Meandering along a perpendicular plane, the pressure receiving surface substantially perpendicular to the load direction of the seating load was formed of a wire crushed so as to be flat, and the crushed shape is a wire having a circular cross section and a width dimension. The ratio to the vertical width is 1.3
The present invention provides an S-spring for a vehicle seat, wherein the S-spring is formed by pressure molding in a range of from 2.5 to 2.5.

[0013]

An S-spring is formed from a spring wire meandering along a plane substantially perpendicular to the load direction of the seating load, and a pressure receiving surface substantially perpendicular to the load direction of the seating load is flat with the spring wire. By using a wire rod that has been crushed so that it becomes less, the use of a cup spring, which has been used in combination with a spring with a round wire in the past, can be omitted.
An abrupt rising portion is generated in the flexure curve, and the cushioning property in this load application region is increased, thereby reducing discomfort and impact when sitting.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS. 1, 2 and 3, a specific example in which the present invention is applied to a vehicle seat will be described. In the following description, the same components as those in FIG. 4 showing the related art are denoted by the same reference numerals in principle, and the description of the same items will be omitted. A plurality of S-springs (15) are attached to a seat frame (4) built in the automobile seat (1) in an aligned state by clips (6).

First, as a first processing stage, a hard steel wire having a circular cross section of, for example, 3.8 mm in diameter is supplied into a bending forming apparatus (not shown) in which, for example, a number of rotary bending rolls are arranged in a meandering manner. Then, a continuous bending process in an S-shape in which the waveform height Ht is 50 mm and the interval Pc between the peak and the valley is 30 mm is performed.

In the subsequent second processing step, the bent S spring (15) is clipped (6) as shown in FIG. 1A by a pressing device or a rolling device (both not shown). Except for the both end portions (R) and (R) that function as engagement portions with the intermediate portion Pr
Is pressed at room temperature so that the ratio of the horizontal width W to the vertical width H is 1.8 over 420 mm, and this portion is formed into a conical shape with a flat cross section. The intermediate portion Pr is set according to design conditions.

At the time of forming the conical crushed portion (10), as shown in FIG. 1 (B), a width W in a direction orthogonal to a direction in which the press load acts and a length H of the press load. It was determined that selecting a ratio W / H within the range of 1.3 to 2.5 from the range of 1.3 to 2.5 provides suitable seating load / bending characteristics in connection with the room-temperature molding of the round wire. That is, when the value of W / H is 1.3 or less, the effect of the present invention cannot be expected. When the value is 2.5 or more, the limit of plastic working is exceeded,
Since cracks are generated, heat treatment is required and the cost increases.

The curve A according to the present invention is shaped under the above-mentioned crushing conditions, so that the above-mentioned S incorporated in the sheet (1) is formed.
When seating load P is loaded in the middle part of the spring (15) (Pr), as shown in FIG. 2, rapidly with rising, a circular cross section in the vicinity of the maximum load the load point P ₂ deflection S is maximum Compared to the curve B when only the conventional S spring (5) is used, the seating load P at the end of sitting is 20 to 30.
%.

In the above embodiment, both ends (R)
(R) is left in a non-crushed state with a round wire in order to improve the engagement with the clip (6), but if the structure of the clip (6) is changed, both ends of the S spring (15) can be changed. Part (R)
(R) can be crushed similarly to the intermediate portion (Pr).

In short, by using the S-spring of the present invention, a desired load / deflection curve can be obtained even if the cup spring conventionally used together with the S-spring is omitted or the configuration is simplified, and the cost can be reduced. You can do it.

[0021]

The S spring (1) incorporated as a shape restoring member and a cushioning member in a vehicle seat (1).
5), a conical crushing portion (1) having a flat pressure receiving surface
Forming 0) makes it possible to generate a sharp rising portion in the sitting load P / deflection S curve. As a result, it is possible to effectively avoid a reduction in impact resistance performance when seated, and to omit the cup spring (7) used in combination with the conventional S spring (5) having a circular cross section, and to provide a trim cover ( 2) It is possible to reduce the thickness of the pad (3) to be filled in, and accordingly, the manufacturing cost of the sheet (1) is reduced. Further, since the pressure receiving surface of the S-spring is arranged flat with respect to the seating load, even when a thin pad (3) is used, the uncomfortable feeling at the time of sitting is reduced, and the seat (1) having a comfortable seating is obtained.

The ratio of the width W to the height H of the crushed portion (10) is preferably in the range of 1.3 to 2.5.

[Brief description of the drawings]

1A is a front view of an S spring for a vehicle seat according to the present invention, FIG. 1B is a cross-sectional view of a main part of the S spring, and FIG. 1C is a partial perspective view of a main part of the S spring.

FIG. 2 is a seat load / bending diagram.

FIG. 3 is a partially cutaway perspective view of a vehicle seat incorporating an S-spring according to the present invention.

4A is a partially cutaway perspective view of a vehicle seat incorporating a conventional S spring, and FIG. 4B is a perspective view illustrating an S spring attached to a seat frame.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vehicle seat 10 Crushed part 11 Non-crushed part 15 S spring P Seating load S deflection

Claims (2)

(57) [Claims] An S-spring that stretches on a seat frame built in a vehicle seat and imparts elasticity, meanders along a plane substantially perpendicular to a load direction of a seating load, and loads the seating load. An S-spring for a vehicle seat, wherein the S-spring is formed of a wire crushed so that a pressure-receiving surface substantially orthogonal to a direction becomes flat. 2. The flat pressure-receiving surface is formed by forming a spring wire having a circular cross section into a ratio of a horizontal width dimension orthogonal to a direction in which a press load acts on a crushed portion to a vertical width dimension in a direction in which a press load acts. 2. The S-spring for a vehicle seat according to claim 1, wherein the S-spring is formed in a pressure range of 1.3 to 2.5 at normal temperature.