CUSHION SPRING

There is provided a cushion spring including: a formed wire bridged to a seat cushion frame in a seat front-rear direction; and a resin member joined to the formed wire. A center wire and a side wire of the formed wire each include a plurality of crank-shaped portions that are bent to fold in a crank shape to one side and the other side in a seat width direction alternately. The resin member includes a deflection restricting portion that connects the plurality of crank-shaped portions to restrict a divergence in the seat front-rear direction between three or more crank-shaped portions, the three or more crank-shaped portions being formed in the side wire and arranged side by side consecutively in the seat front-rear direction.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based on and claims priority under 35 USC 119 from Japanese Patent Application No. 2023-114312 filed on Jul. 12, 2023, the contents of which are incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a cushion spring. Specifically, the invention relates to a cushion spring that is bridged to a seat cushion frame in a seat front-rear direction and receives a load of a seated occupant by a surface thereof.

BACKGROUND ART

JP2019-073115A discloses a cushion spring that is bridged to a seat cushion frame forming a framework of a seat cushion and receives a load of a seated occupant by a surface thereof. The cushion spring includes a pair of left and right formed wires bridged between a frame front portion and a frame rear portion of the seat cushion frame. Each formed wire is folded in a U-shape in a plan view. A center wire and a side wire of each formed wire that are folded are bridged between the frame front portion and frame rear portion of the seat cushion frame so as to extend in a front-rear direction.

In the configuration described in JP2019-073115A, the center wire and the side wire are symmetrical to each other. Therefore, when increasing the roll rigidity of a side portion of the seat cushion, it is necessary to partially hardens a side portion of a cushion pad. However, in a configuration in which the hardness of the cushion pad is partially changed, elasticity weakening, a variation in position, and a variation in hardness are likely to occur in the pad, and the roll rigidity cannot be stably increased. Therefore, the present invention provides a cushion spring capable of appropriately increasing roll rigidity of a side portion of a seat cushion.

SUMMARY OF INVENTION

To solve the above problems, a cushion spring according to the present invention is configured as follows.

According to a first aspect of the present disclosure, a cushion spring configured to receive a load of a seated occupant by a surface of the cushion spring includes: a formed wire configured to be bridged to a seat cushion frame in a seat front-rear direction; and a resin member that is joined to the formed wire. The formed wire is formed of one wire having a center wire and a side wire that are arranged side by side in a seat width direction and extend in the seat front-rear direction such that one ends of the center wire and the side wire are connected to each other. The center wire and the side wire are arranged in an order of the center wire and the side wire from a center of the seat cushion frame to an outer side in the seat width direction. The center wire and the side wire each include a plurality of crank-shaped portions that are bent to fold in a crank shape to one side and the other side in the seat width direction alternately. The resin member includes a deflection restricting portion that connects the plurality of crank-shaped portions to restrict a divergence in the seat front-rear direction between three or more crank-shaped portions, the three or more crank-shaped portions being formed in the side wire and arranged side by side consecutively in the seat front-rear direction.

According to the first aspect of the present invention, the deflection restricting portion of the resin member effectively restricts the deflection of the crank-shaped portion formed in the side wire. Accordingly, the side wire is less likely to sink downward when a load of a seated occupant is received by a surface thereof. As a result, roll rigidity of a side portion of a seat cushion is appropriately increased.

According to a second aspect of the present disclosure, in the first aspect, the resin member has a pad supporting surface configured to support a seat cushion pad from a back side of the seat cushion pad at a position higher than the plurality of crank-shaped portions.

According to the second aspect of the present invention, the pad supporting surface formed on the resin member can function as a receiving surface when the load of the seated occupant is applied to the side portion of the seat cushion. Since the pad supporting surface is provided integrally with the side wire of the cushion spring whose deflection is restricted, the pad supporting surface is less likely to sink downward and can stably receive the load.

According to a third aspect of the present disclosure, in the first or second aspect, the deflection restricting portion extends to continuously connect all the crank-shaped portions in the seat front-rear direction.

According to the third aspect of the present invention, it is possible to more effectively restrict the side wire from sinking downward. As a result, the roll rigidity of the side portion of the seat cushion can be more appropriately increased.

According to a fourth aspect of the present disclosure, in the third aspect, the deflection restricting portion includes an expanding portion that is expanded such that a connecting width in the seat width direction of a portion connecting the crank-shaped portions is continuously or intermittently increased toward a seat rear side on an inner side in the seat width direction.

According to the fourth aspect of the present invention, the hardness of the side portion of the seat cushion can be adjusted such that the roll rigidity increases toward the seat rear side where a pressure by sitting of the seated occupant is higher, and the roll rigidity decreases toward a seat front side where the pressure by sitting of the seated occupant is lower. Accordingly, it is possible to achieve both the improvement of the sitting comfort when seated and the improvement of the roll rigidity.

According to a fifth aspect of the present disclosure, in the fourth aspect, the expanding portion expands beyond at least one of the crank-shaped portions on the inner side in the seat width direction.

According to the fifth aspect of the present invention, the roll rigidity of the side portion of the seat cushion can be more appropriately increased in a region where the expanding portion extends beyond the crank-shaped portion on the inner side in the seat width direction.

According to a sixth aspect of the present disclosure, in the first or second aspect, the formed wire has a symmetrical shape in the seat width direction, and the formed wire includes a pair of formed wires provided to be symmetrical to each other in the seat width direction with respect to the seat cushion frame.

According to the sixth aspect, since the formed wire has a symmetrical shape, the formed wire can be easily formed. Further, it is possible to relatively easily increase the roll rigidity of both side portions of the seat cushion symmetrically in the seat width direction.

DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments according to the present invention will be described with reference to the drawings.

First Embodiment

Schematic Configuration of Cushion Spring10

First, a configuration of a cushion spring10according to a first embodiment of the present invention will be described with reference toFIGS.1to6. In the following description, when a direction such as front, rear, up, down, left, or right is described, it is assumed that the direction indicates a corresponding direction illustrated in the drawings.

When combinations of the directions with a word “seat” are described such as a “seat width direction”, the combinations indicate directions based on a seat cushion1. In addition, in the following description, when a specific reference diagram is not described or when there is no corresponding reference numeral in the reference diagram, any one ofFIGS.1to6is referred to as appropriate.

As illustrated inFIG.1, the cushion spring10according to the present embodiment is applied to the seat cushion1of an automobile seat. The automobile seat includes a seatback (not illustrated) serving as a backrest for a seated occupant and the seat cushion1serving as a seating portion.

The seat cushion1is installed on a floor of an automobile (not illustrated). The seat cushion1includes a seat cushion frame2that forms a framework thereof, a seat cushion pad3that covers the seat cushion frame2from above, and a seat cushion cover4that covers the seat cushion pad3from a pad surface side.

The seat cushion1further includes the cushion spring10that is bridged to the seat cushion frame2in a seat front-rear direction. The cushion spring10functions as a pad receiving portion that receives a load of a seated occupant by a surface thereof via the seat cushion pad3.

As illustrated inFIG.2, the seat cushion frame2is formed of a metal member assembled in a frame shape in a plan view. Specifically, the seat cushion frame2includes lower arms2A that form left and right side frameworks of the seat cushion1and a front pipe2B that is integrally bridged between front portions of the lower arms2A. The seat cushion frame2further includes a rear pipe2C that is integrally bridged between rear portions of the lower arms2A and a front panel2D that is integrally bridged between upper edges of front ends of the lower arms2A.

Referring toFIG.1, the seat cushion pad3is formed of a polyurethane foamed body. The seat cushion pad3is set in a manner of covering the entire upper portion of the seat cushion frame2from above the seat. Accordingly, the seat cushion pad3is set such that a peripheral portion thereof is firmly supported by the seat cushion frame2from below the seat and a central portion thereof is softly supported by the cushion spring10from below the seat.

The seat cushion cover4is formed of a planar fabric member. The seat cushion cover4covers, from the pad surface side, the seat cushion pad3set on the upper portion of the seat cushion frame2. The seat cushion cover4is fixed to the seat cushion frame2such that front, rear, left, and right ends of the seat cushion cover4are pulled below the seat. Accordingly, the seat cushion cover4is widely stretched over the pad surface of the seat cushion pad3, and holds the seat cushion pad3in a state of being pressed against the upper portion of the seat cushion frame2and fixed in position.

As illustrated inFIG.3, the cushion spring10includes a pair of left and right formed wires11each formed of a rod-shaped processed spring bent in a U shape in a plan view, and a resin member12joined to each formed wire11. As illustrated inFIG.4, each formed wire11is formed of one wire bent in a U shape in a plan view.

Specifically, each formed wire11is formed of a wire having a U shape in a plan view which is bent to have a center wire11A and a side wire11B. The center wire11A and the side wire11B are arranged side by side in the seat width direction and extend in the seat front-rear direction. The center wire11A and the side wire11B each have a U shape in a plan view in which rear ends thereof are connected to each other and front ends thereof are spaced apart from each other.

Each formed wire11has a symmetrical shape in the seat width direction. Further, the formed wires11are arranged in a manner of being symmetrical to each other in the seat width direction. As illustrated inFIG.3, each formed wire11is provided such that a wire arranged on a center side of the seat cushion frame2in the seat width direction is defined as the center wire11A and a wire arranged on an outer side is defined as the side wire11B.

At each of the front ends of the center wire11A and the side wire11B of each formed wire11, a front hooking portion11C is formed that is bent in a shape allowing the front hooking portion11C to be hooked on the front pipe2B from above. Further, at each of the rear ends of the center wire11A and the side wire11B of each formed wire11, a rear hooking portion11D is formed that is bent in a shape allowing the rear hooking portion11D to be hooked on the rear pipe2C from above.

As illustrated inFIG.4, the center wire11A of each formed wire11is formed with a plurality of crank-shaped portions A1that are bent in a manner of folding in a crank shape to one side and the other side in the seat width direction alternately, and the side wire11B of each formed wire11is formed with a plurality of crank-shaped portions B1that are bent in a manner of folding to one side and the other side in the seat width direction alternately. In each formed wire11, the crank-shaped portions A1formed in the center wire11A and the crank-shaped portions B1formed in the side wire11B are formed symmetrically in the seat width direction such that the crank-shaped portions A1and B1approach or separate from each other in the seat width direction.

With the crank-shaped portions A1and B1, each formed wire11has a shape extending in the seat width direction as well as in the seat front-rear direction. Accordingly, each formed wire11is able to planarly support the seat cushion pad3(seeFIG.1) from a pad back side.

Each formed wire11is formed such that the center wire11A and the side wire11B thereof are bent in a V shape in a side view. With the bending in the V shape, each formed wire11allows a rear portion (a portion where the pad thickness is increased downward) of the seat cushion pad3(seeFIG.1), which supports the ischium of the seated occupant, to sink deeply downward.

As illustrated inFIG.3, the resin member12is joined to the formed wires11in a manner of being symmetrical in the seat width direction. Specifically, the resin member12includes a pair of deflection restricting portions12A that are joined to the formed wires11in a manner of extending in the seat front-rear direction along the side wires11B respectively.

Further, the resin member12has a pad supporting surface12B that forms an upper surface of each deflection restricting portion12A. Each pad supporting surface12B is formed at a position higher than the side wire11B, and forms a support surface that planarly supports the seat cushion pad3(seeFIG.1) from the pad back side.

The resin member12further includes a connecting portion12C extending in the seat width direction to connect rear portions of the deflection restricting portions12A. The resin member12is integrally joined to the formed wires11by integral molding with the formed wires11.

Next, a detailed configuration of the resin member12will be described. As illustrated inFIG.5, each deflection restricting portion12A is formed in a manner of continuously extending in the seat front-rear direction along linear longitudinal wire portions B2of the corresponding side wire11B. The longitudinal wire portions B2extend intermittently in the seat front-rear direction between the corresponding front hooking portion11C and the corresponding rear hooking portion11D. The longitudinal wire portions B2of each side wire11B are formed at positions on the same straight line.

Accordingly, each deflection restricting portion12A is formed to connect all the crank-shaped portions B1of the corresponding side wire11B that are adjacent to each other in the front-rear direction. Each deflection restricting portion12A includes an expanding portion A2that is expanded such that a connecting width in the seat width direction of a portion connecting the crank-shaped portions B1is continuously increased toward the seat rear side on an inner side in the seat width direction.

Each expanding portion A2has a shape of expanding so as to define an inner peripheral edge in a recessed curved surface shape in a plan view along an outer edge of the hip portion of a seated person. With the expanding portion A2, each deflection restricting portion12A has a shape in which a connecting width of a portion connecting the foremost crank-shaped portion B1and the second crank-shaped portion B1counting from the front of each side wire11B is the smallest.

Each deflection restricting portion12A has a shape in which a connecting width of a portion connecting the second crank-shaped portion B1from the front and the third crank-shaped portion B1from the front of the corresponding side wire11B is wider. Each deflection restricting portion12A has a shape in which a connecting width of a portion connecting the third crank-shaped portion B1from the front and the fourth crank-shaped portion B1from the front of the corresponding side wire11B is further wider.

Specifically, each deflection restricting portion12A has a shape of, at the middle of a portion connecting the third crank-shaped portion B1from the front and the fourth crank-shaped portion B1from the front of each side wire11B, expanding beyond the third crank-shaped portion B1and the fourth crank-shaped portion B1on the inner side in the seat width direction and being connected to the connecting portion12C. In this sense, each expanding portion A2, which expands beyond the third crank-shaped portion B1from the front and the fourth crank-shaped portion B1from the front on the inner side in the seat width direction from the middle of the portion connecting the third crank-shaped portion B1and the fourth crank-shaped portion B1, is a part of the connecting portion12C.

Each deflection restricting portion12A is not formed at a portion (not illustrated) that supports the ischium of the seated occupant, and is formed at a position retracted to the outer side in the seat width direction from the portion that supports the ischium. The connecting portion12C is not formed at the portion (not illustrated) that supports the ischium of the seated occupant, and is formed at a position that is retracted to the seat rear side from the portion that supports the ischium.

With the deflection restricting portion12A, a divergence between the crank-shaped portions B1arranged by five in the front-rear direction of each side wire11B of each formed wire11is restricted. Specifically, in each side wire11B, the divergence in the seat front-rear direction between the foremost crank-shaped portion B1and the second crank-shaped portion B1from the front is restricted on a lowest level by the shape in which the connecting width of the corresponding deflection restricting portion12A changes.

Further, in each side wire11B, the divergence in the seat front-rear direction between the second crank-shaped portion B1from the front and the third crank-shaped portion B1from the front is restricted on a high level. Further, in each side wire11B, the divergence in the seat front-rear direction between the third crank-shaped portion B1from the front and the fourth crank-shaped portion B1from the front is restricted on a higher level.

Further, in each side wire11B, since the fourth crank-shaped portion B1from the front and the fifth crank-shaped portion B1from the front are connected to each other over the entire region in the seat width direction by the corresponding deflection restricting portion12A, the divergence in the seat front-rear direction therebetween is completely restricted. With the resin member12, even when the formed wires11are formed symmetrically to each other in the seat width direction, the cushion spring10has different flexibility in the center wire11A and the side wire11B of each formed wire11at the time of receiving a load from the seated occupant.

Specifically, as illustrated inFIG.6, when the cushion spring10receives a load from the seated occupant, each center wire11A is deflected in a manner of sinking downward relatively flexibly. On the other hand, deflection of each side wire11B is restricted so that the side wire11B is less likely to sink downward than each center wire11A.

Specifically, the load from the seated occupant decreases from the rear portion of the seat toward the front portion of the seat, and the level of deflection restriction of each side wire11B gets lower toward the front side and gets higher toward the rear side by the shape in which the connecting width of each deflection restricting portion12A changes. Accordingly, the roll rigidity of each side portion of the seat cushion1can be appropriately increased.

The pad supporting surface12B forming the upper surface of each deflection restricting portion12A functions as a receiving surface of the seat cushion pad3when the load of the seated occupant is applied to each side portion of the seat cushion1. Since each pad supporting surface12B is provided integrally with the corresponding side wire11B of the cushion spring10whose deflection is restricted, the pad supporting surfaces12B are less likely to sink downward and can stably receive the load.

More specifically, since the pad supporting surfaces12B are integrally connected to each other by the connecting portion12C, when a load from the seated occupant is applied to one pad supporting surface12B, the load is also transmitted to the side wire11B on the opposite side via the other pad supporting surface12B. Accordingly, when the load of the seated occupant is applied to the side portions of the seat cushion1, the pad supporting surfaces12B are less likely to sink downward and can stably receive the load.

As illustrated inFIG.5, a groove, which is recessed along the shape of each side wire11B and formed in each pad supporting surface12B, is a groove through which a pressing pin for fixing the position of the corresponding formed wire11in a mold of the resin member12is passed.

To summarize the above, the cushion spring10according to the present embodiment may have the following configuration. In the following description, reference signs assigned in parentheses correspond to the configurations described in the above embodiment.

That is, a cushion spring (10) is a spring that is bridged to a seat cushion frame (2) in a seat front-rear direction and receives a load of a seated occupant by a surface thereof. The cushion spring (10) includes a formed wire (11) that is bridged to the seat cushion frame (2) in the seat front-rear direction, and a resin member (12) that is joined to the formed wire (11).

The formed wire (11) is formed of a single wire having a center wire (11A) and a side wire (11B). The center wire (11A) and the side wire (11B) are arranged side by side in a seat width direction and extend in the seat front-rear direction so that one ends thereof are connected to each other. The center wire (11A) and the side wire (11B) are arranged in this order from a center of the seat cushion frame (2) to an outer side in the seat width direction.

The center wire (11A) and the side wire (11B) each include a plurality of crank-shaped portions (A1, B1) that are bent in a manner of folding in a crank shape to one side and the other side in the seat width direction alternately. The resin member (12) includes a deflection restricting portion (12A) that connects the plurality of crank-shaped portions (B1) to restrict a divergence in the seat front-rear direction between three or more crank-shaped portions (B1), the three or more crank-shaped portions (B1) being formed in the side wire (11B) and arranged side by side consecutively in the front-rear direction.

According to the above configuration, the deflection restricting portion (12A) of the resin member (12) effectively restricts the deflection of the crank-shaped portion (B1) formed in the side wire (11B). Accordingly, the side wire (11B) is less likely to sink downward when a load of a seated occupant is received by a surface thereof. As a result, roll rigidity of a side portion of a seat cushion (1) is appropriately increased.

Further, the resin member (12) has, at a position higher than the plurality of crank-shaped portions (B1), a pad supporting surface (12B) that supports a seat cushion pad (3) from a pad back side on a surface basis. According to the above configuration, the pad supporting surface (12B) formed on the resin member (12) can function as a receiving surface when the load of the seated occupant is applied to the side portion of the seat cushion (1). Since the pad supporting surface (12B) is provided integrally with the side wire (11B) of the cushion spring (10) whose deflection is restricted, the pad supporting surface (12B) is less likely to sink downward and can stably receive the load.

Further, the deflection restricting portion (12A) extends in a manner of continuously connecting all the crank-shaped portions (B1) in the seat front-rear direction. According to the above configuration, it is possible to more effectively restrict the side wire (11B) from sinking downward. As a result, the roll rigidity of the side portion of the seat cushion (1) can be more appropriately increased.

Further, the deflection restricting portion (12A) includes an expanding portion (A2) that is expanded such that a connecting width in the seat width direction of a portion connecting the crank-shaped portions (B1) is continuously increased toward a seat rear side on an inner side in the seat width direction. According to the above configuration, the hardness of the side portion of the seat cushion (1) can be adjusted such that the roll rigidity increases toward the seat rear side where a pressure by sitting of the seated occupant is higher, and the roll rigidity decreases toward a seat front side where the pressure by sitting of the seated occupant is lower. Accordingly, it is possible to achieve both the improvement of the sitting comfort when seated and the improvement of the roll rigidity.

Further, the expanding portion (A2) expands beyond the crank-shaped portion (B1) on the inner side in the seat width direction. According to the above configuration, the roll rigidity of the side portion of the seat cushion (1) can be more appropriately increased in a region where the expanding portion (A2) extends beyond the crank-shaped portion (B1) on the inner side in the seat width direction.

Further, a pair of the formed wires (11) are provided that are symmetrical to each other in the seat width direction with respect to the seat cushion frame (2) and each of which has a symmetrical shape in the seat width direction. According to the above configuration, since the formed wire (11) has a symmetrical shape, the formed wire (11) can be easily formed. Further, it is possible to relatively easily increase the roll rigidity of both side portions of the seat cushion (1) symmetrically in the seat width direction.

Regarding Other Embodiments

Although the embodiment of the present invention has been described above with reference to one embodiment, the present invention can be implemented in various embodiments other than the above embodiment.

1. The cushion spring according to the present invention is applicable not only to a seat cushion of a seat to be mounted on a vehicle such as an automobile or a railroad vehicle, but also to a seat cushion of a seat to be mounted on other vehicles such as an aircraft or a ship. The cushion spring is also applicable to a seat cushion of a seat not to be mounted on a vehicle.

2. In the cushion spring, the pair of formed wires may not necessarily be provided to be symmetrical to each other in the seat width direction with respect the seat cushion frame. That is, one formed wire may have a shape different from that of the other formed wire. Further, in the formed wire, the center wire and the side wire may not necessarily be symmetrical to each other in the seat width direction.

3. The pad supporting surface of the resin member may form the upper surface of the deflection restricting portion, or may form an upper surface of a region separated from the deflection restricting portion. It is sufficient that the deflection restricting portion connects the plurality of crank-shaped portions to restrict the divergence in the seat front-rear direction between three or more crank-shaped portions arranged side by side consecutively. Accordingly, the deflection restricting portion may have a configuration of directly connecting only the foremost crank-shaped portion and the rearmost crank-shaped portion among the three or more crank-shaped portions arranged side by side consecutively and not connecting the crank-shaped portions located therebetween.

The expanding portion of the deflection restricting portion may be formed such that the connecting width in the seat width direction of the portion connecting the crank-shaped portions is continuously increased toward the seat rear side on the inner side in the seat width direction, or may be formed such that the connecting width is intermittently increased. That is, the expanding portion may be provided with a region in which the connecting width is partially narrowed or kept constant. Further, the deflection restricting portion may have a shape in which the connecting width is constant over the entire region in the seat front-rear direction or the connecting width is increased toward the seat front side.