Vehicle seat back frame member with adjustable stiffness system and method

Abstract

Systems and methods for varying stiffness of a structural member. A vehicle seat includes a structural member. The structural member has two walls. A link extends between the walls and has three sections, one section extending between the other two sections. A connector is disposed between the other two sections of the link and the two walls of the structural member. The connector may be adjustable to vary tension in the link and to vary stiffness of the structural member.

Description

Technical Field

[0001] The present disclosure relates generally to vehicle seats having a frame made from a structural member, and more particularly to a structural seat member having an adjustable stiffness. Background Art

[0002] Vehicle seats are designed for structural integrity and performance under a variety of expected and potential load scenarios that may occur during vehicle operation. Various seat design parameters have an impact on both structural integrity and occupant motion response. When a vehicle in which an occupant is seated experiences sudden and rapid forward acceleration, the occupant's head may tilt backward and then reverse back to tilt forward in reaction. The seat and its head restraint can help minimize the tilting motion, thereby affecting the occupant's motion response.

[0003] Modeling and testing can be used during product development to determine design parameters for desired performance. Once determined, the seat's components can be customized for each seat and vehicle combination. Certain parts of the seat are unique to each application and often cannot be reused in other applications without changing the design.

[0004] Therefore, it is desirable to provide a vehicle seat having a structural member that meets a range of different performance requirements. In addition, the structural member of the vehicle seat can preferably be reused in various applications without requiring redesign. Moreover, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing introduction. Summary of the invention

[0005] A system and method for changing the stiffness of a structural member is provided. A vehicle seat includes a structural member. The structural member has two walls. A connecting rod extends between the walls and has three sections, one of which extends between the other two sections. A connector is disposed between the other two sections of the connecting rod and the two walls of the structural member. The connector can be adjustable to change the tension in the connecting rod and change the stiffness of the structural member. The number of walls, connecting rods and / or connections is not limited to the above examples, but can be various combinations as it relates to the varying stiffness of the structural member.

[0006] In an additional embodiment, a head restraint of a vehicle seat is coupled to a structural member and a frame is included in the vehicle seat, wherein the structural member comprises a portion of the frame.

[0007] In additional embodiments, the structural member includes a channel forming a slot cavity, and the connecting rod is disposed in the slot cavity.

[0008] In an additional embodiment, the structural member includes a web and a third wall. The structural member includes a channel forming a slot cavity. One wall is a leg of the channel. Another wall is the web. The third wall is a second leg of the channel. The web extends between the two legs to form a C-shape. A connecting rod is connected to the two legs and the web.

[0009] In an additional embodiment, the vehicle seat has a backrest and the structural member is an upper cross member of the backrest.

[0010] In additional embodiments, a head restraint is included on a vehicle seat, wherein the connector is configured to adjust stiffness to balance a response of the head restraint to an expected force with a response of the head restraint to a rebound force.

[0011] In additional embodiments, the connecting rod is a stamping and is arranged to extend along the structural member.

[0012] In additional embodiments, the structural member includes a channel configured to provide stiffness to the structural member. The structural member includes an angle extending from the channel and configured to increase stiffness. The connecting rod is configured to increase stiffness.

[0013] In additional embodiments, the connector is configured to place the link in tension and compression.

[0014] In additional embodiments, the connector is a threaded fastener.

[0015] In various other embodiments, a system with adjustable stiffness includes a vehicle seat having a frame. A structural member of the frame of the vehicle seat has two walls. A connecting rod extends between the walls. The connecting rod has three sections, with a middle section extending between two other outer sections. One outer section is disposed along one wall of the structural member, and another outer section is disposed along another wall of the structural member. A connector is engaged between a section of the connecting rod and a wall of the structural member. Another connector is engaged between another section of the connecting rod and another wall of the structural member. At least one connector is adjustable to change the tension in the middle section of the connecting rod and change the stiffness of the structural member.

[0016] In an additional embodiment, the head restraint is included on a vehicle seat. An axle couples the head restraint to the frame at the structural member.

[0017] In an additional embodiment, the structural member includes a channel having an opening. The channel forms a slot cavity, and the connecting rod is disposed in the slot cavity.

[0018] In an additional embodiment, the structural member includes a web and a third wall, and includes a channel forming a slot cavity. Two walls form legs of the channel, and the other forms the web. The web extends between the legs so that the legs and the web form a C-shape. A connecting rod is connected to the legs and the web.

[0019] In an additional embodiment, a vehicle seat has a backrest, and the structural member is disposed in the backrest and includes an upper cross member of the frame.

[0020] In an additional embodiment, the head restraint is included in a vehicle seat. The two connectors are configured to adjust stiffness to balance the response of the head restraint to the expected force with the response of the head restraint to the rebound force.

[0021] In additional embodiments, the connecting rod is a metal stamping and is arranged to extend in a horizontal direction along the structural member.

[0022] In additional embodiments, the structural member includes a channel that provides stiffness to the structural member. The structural member includes an angle extending from the channel to increase stiffness. In addition to the increase in angle, the connecting rod increases stiffness.

[0023] In a number of further embodiments, a method for adjustable stiffness includes constructing a vehicle seat. A structural member is included in the vehicle seat. The structural member has a first wall and a second wall. A connecting rod extends between the first wall and the second wall. The connecting rod has a first section, a second section, and a third section, wherein the second section extends between the first section and the third section. A first connector is added between the first section of the connecting rod and the first wall of the structural member. A second connector is added between the third section of the connecting rod and the second wall. The first connector and / or the second connector are adjusted to change the tension in the second section of the connecting rod and change the stiffness of the structural member.

[0024] In an additional embodiment, a head restraint is included on a vehicle seat. A balance between an expected force on the head restraint and a resilient force from the head restraint is evaluated. A baseline stiffness of a structural member is determined based on the evaluation of the balance. A base design of the structural member is created to provide a baseline stiffness. The baseline stiffness is adjusted with a link to provide a varying stiffness of the structural member. The base design is reused in various applications requiring different stiffnesses provided by adjusting the baseline stiffness. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Exemplary embodiments will be described below with reference to the following drawings, wherein like numerals represent like elements, and wherein:

[0026] Figure 1 is a schematic diagram of a vehicle seat according to various embodiments;

[0027] Figure 2 According to various embodiments Figure 1 A schematic perspective view of a frame of a seat;

[0028] Figure 3 According to various embodiments Figure 1 A perspective view of the structural components of a seat;

[0029] Figure 4 A device having an adjustable reinforcement according to various embodiments Figure 3 A schematic cross-sectional view of a structural member;

[0030] Figure 5 According to various embodiments Figure 4 A perspective view of an adjustable reinforcement member; and

[0031] Figure 6 According to various embodiments, there is another adjustable reinforcement member Figure 3 Schematic cross-section of a structural member. DETAILED DESCRIPTION

[0032] The following detailed description is merely exemplary in nature and is not intended to limit the application and uses. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding introduction, brief summary or the following detailed description.

[0033] refer to Figure 1 , shows an example of a vehicle 20 having a body 22, with a seat 24 mounted on the body. Typically, the seat 24 has a seat bottom 26, a seat back 28, and a head restraint 30. The head restraint 30 is connected to the seat back 28. For example, one or more shafts 32 connect the head restraint 30 to a structural member 34 in a frame 36 of the seat back 28 and provide support for the head restraint 30. In various embodiments, the structural member 34 may be referred to as a structural portion, structure, beam, or frame portion. In all cases, the structural member 34 provides an element of the frame 36 that provides shape characteristics and load-bearing capacity.

[0034] During operation of the vehicle 20, the head restraint 30 may be subjected to loads. For example, during a rear collision, the occupant 38 or a portion of the occupant 38 (such as their head) may move rearward, applying a force 40 (expected force) to the head restraint 30. The force 40 is transferred to the frame 36 at the structural member 34 through the shaft 32. This causes a moment 42 to be generated at the structural member 34. The structural member 34 or a portion thereof may be elastically deformed, such as by twisting, bending or otherwise yielding. In fact, the deformation is elastic and a bit like a coil spring. The deformation allows the head restraint 30 to move in the rearward direction 44 so that the occupant does not encounter a hard stop. As the force 40 decreases, the system rebounds and the structural member 34 returns to its original state, which moves the head restraint 30 in the forward direction 46 due to its elasticity. The head restraint 30 may also apply a force 48 (rebound force) to the occupant 38 as it moves to its normal position.

[0035] During the development of the vehicle 20 and the seat 24, the parameters of the elastic deformation of the structural member 34 can be evaluated for the expected load through the force 40. The evaluation can be performed using commercially available modeling software and / or real-world testing. The stiffness can be evaluated, where the stiffness is a measure of the resistance to elastic deformation provided by the structural member 34. The design of the structural member 34 can be based on providing sufficient stiffness so that under the expected force (force 40), the amount of elastic deformation is limited to limit the amount of movement of the occupant 38 or a part of the occupant 38, so that the head restraint 30 provides its expected restraint function. In addition, the structural member 34 can be designed to have a sufficiently low stiffness to avoid excessive rebound force loads in the form of rebound forces (force 48) applied to the occupant 38. When the balance is set, the design stiffness of the structural member 34 is specific to the vehicle 20 / seat 24 combination. In other seats and / or other vehicles, different stiffness of the structural member 34 may be expected based on the applicable evaluation of the structural member 34.

[0036] refer to Figure 2 , the frame 36 of the seat 24 is shown without its cushioning and fabric covering. The structural member 34 is configured in the form of an upper cross member at the top of the frame 36 of the seat back 28. In this embodiment, the structural member 34 spans between the two side members 50, 52. The structural member 34 is fixed to the side members 50, 52, such as by welding, fastening or other methods. In some embodiments, the structural member 34 can be formed integrally with one or both of the side members 50, 52. The frame 36 also includes a lower cross member 54 in the seat back 28 and a bracket 56, each of which extends between the side members 50, 52. In other embodiments, the frame 36 of the seat back 28 may include a different number of structural members.

[0037] refer to Figure 3 , which shows the isolated structural member 34 removed from the seat frame 36 and viewed from a rear perspective. The structural member 34 is shown without the adjustable stiffness system described below. The structural member 34 is formed as a stamping, such as steel, having openings 60, 62 for receiving the shaft 32. The structural member 34 extends between a right end 64 connected to the side member 50 and a left end 65 connected to the side member 52, as shown in FIG. Figure 2 In terms of structural cross-sectional shape, the structural member 34 is generally formed into a generally "C"-shaped upper channel 66 and a generally angled overall lower corner 68. To manufacture the structural member, a variety of material options and processes are available, and the general shape is not limited to a "C" shape, and can take any shape that can achieve the desired performance.

[0038] In this non-limiting example, the upper channel 66 and the lower corner 68 share a common leg 70. The upper channel 66 has an open side 67 facing the rear, and includes a leg 70 and a leg 72 connected to the leg 70 by a web 74. The leg 72 includes a return portion 76 extending on the upper portion of the open side 67 to increase rigidity. In an embodiment, the legs 70, 72 and the web 74 can be collectively referred to as walls. The legs 70 and 72 are in a generally horizontal arrangement, and the web 74 is in a generally vertical arrangement, because considering their similarity to the wall. The upper channel 66 forms a slot cavity 69 enclosed on three sides (walls) by the legs 70, 72 and the web 74. The lower corner 68 includes the leg 70 and another leg 78. The shapes and features of the various parts of the structural member 34 are combined to provide desired parameters, such as strength, rigidity and size. The upper channel 66 provides rigidity, and the lower corner 68 increases the rigidity of the structural member 34.

[0039] refer to Figure 4 , shows a cross section of an adjustable stiffness system 80, specifically a cross section of an upper channel 66 portion of a structural member 34. The adjustable stiffness system 80 includes a link 82 and fasteners 83-85. The link 82 is in the form of an adjustable stiffener that can be adjusted by fasteners 83-85. In the current embodiment, the link 82 is configured as a bracket and is Figure 5 . In other embodiments, the connecting rod 82 can be configured as a cable, a belt, a spring, or any member or members that can be coupled to an element of the upper channel 66 to apply tension or another force and / or compression thereto. In the current embodiment, the fasteners 83-85 are threaded fasteners such as bolts. The fasteners 83-85 are not limited to screw or bolt type fastenings, but can be implemented as any device that changes the tension within the adjustable stiffness system 80, any of which is considered herein to be a fastener, which may also be referred to as a connector. For example, connectors such as belts, clamps, actuators, sliders, or other devices can be used. In some embodiments, some fasteners / connectors can be non-variable fixtures (such as welding), with variable tension provided by other fasteners / connectors.

[0040] like Figure 5As shown in , the connecting rod 82 is formed as a stamping with five segments 91-95, each of which is substantially planar and bent at various angles relative to its adjacent segments in the segments 91-95. The size of the connecting rod 82 is designed to be received in the groove cavity 69. Segments 91, 93 and 95 are fastening segments, and each segment is configured to be connected to the structural member 34. Segments 91, 93 and 95 each include a plurality of openings, which can be threaded or include threaded features to receive connectors such as fasteners 83-85. The shape of segment 91 is used to be positioned in the groove cavity 69 along the leg 72 of the upper channel 66. The shape of segment 93 is used to be positioned in the groove cavity 69 along the web 74 of the upper channel 66. The shape of segment 95 is used to be positioned in the groove cavity 69 along the leg 70 of the upper channel 66. Segments 92, 94 are configured as tension / compression segments for carrying forces between their corresponding fastening segments. Segment 92 extends between segments 91 and 93. Segment 94 extends between segments 93 and 95 .

[0041] like Figure 4 , with the connecting rod 82 positioned in the slot cavity 69, the fastener 83 extends through the leg 72 and engages the segment 91, the fastener 84 extends through the web 74 and engages the segment 93, and the fastener 85 extends through the leg 70 and engages the segment 95. In this embodiment, the fasteners 83, 84, 85 are screwed into their respective segments 91, 93, 95. The fastener 83 can be tightened (increasing torque) to pull the segment 91 toward the leg 72, and can be loosened (reducing torque) to allow the segment 91 to move away from the leg 72, or a reverse torque can be applied to compress the segment 92. The fastener 84 can be tightened to pull the segment 93 toward the web 74, and can be loosened to allow the segment 93 to move away from the web 74, or a reverse torque can be applied to compress the segments 92, 94. The fastener 85 can be tightened to pull the segment 95 toward the leg 70, and can be loosened to allow the segment 95 to move away from the leg 70, or a reverse torque can be applied to compress the segment 94. Adjusting the tension / compression applied in the segments 92 , 94 adjusts the stiffness / spring rate of the adjustable stiffness system 80 and the structural member 34 .

[0042] In an embodiment, fasteners 83-85 form a group disposed at a common location along the horizontal length of structural member 34. Any number of fastener groups may be included along the entire length of structural member 34 between right end 64 and left end 65, depending on factors such as overall length and the force levels involved.

[0043] In an embodiment, increasing the torque on fastener 83 and / or fastener 84 increases the tension in segment 92 of link 82. Increasing the torque on fastener 85 and / or fastener 83 increases the tension in segment 94. Increasing the tension in segment 92 and / or segment 94 increases the stiffness of structural member 34. Reducing the torque on fastener 83 and / or fastener 84 reduces the tension in segment 92. Reducing the torque on fastener 84 and / or fastener 85 reduces the tension in segment 94. Reducing the tension in segment 92 and / or segment 94 reduces the stiffness of structural member 34. In each case, increasing the opposing torque places the corresponding segment 92, 94 in a state of compression. The application of tension or compression changes the spring rate of adjustable stiffness system 80 and structural member 34.

[0044] In an example, the fastener 84 can be fully torqued, pulling the segment 93 against the web 74, and the fasteners 83, 85 can be adjusted to set the desired stiffness. Once set, the fasteners 83-85 can be locked, such as by a lock nut (not shown) or by another locking device, such as a pin, spot weld, stake, etc. In this way, the response of the head restraint 30 to the force 40 and the amount of force 48 generated can be changed and adjusted to suit the application. Therefore, the structural member 34 can be reused in various applications requiring different stiffness levels without redesign.

[0045] To determine the settings for the fasteners 83-85, the balance between expected forces and rebound forces can be evaluated by first determining the baseline stiffness results required for the application of the seat 24 in the vehicle 20 and the basic design of the structural member 34. This can be achieved by applying loads to the structural member 34 and / or by performing detailed analysis of certain expected load conditions using commercially available modeling software and / or testing the response of the head restraint 30 and the impact on the occupant 38. When the resulting stiffness level does not produce the desired results, a stiffness determination is made whether a stiffer system (to improve the performance of the response to the expected force) or a softer system (to improve the response to the rebound force) produces the desired performance in terms of the impact on the occupant 38. Then, by including the adjustable stiffness system 80, the basic design of the structural member 34 can be reused in various applications. The applied tension / compression (such as applied by the fasteners 83-85) adjusts the stiffness / spring rate of the adjustable stiffness system 80, so that the structural member 34 can be adjusted to suit the application. Based on the stiffness assessment, more or less tension or compression is applied to the system. In an embodiment, certain fastening points may be allowed to slide, maintain tension, or enter compression as desired. The stiffness assessment may be repeated to provide an optimized preload for performance improvement. A design of experiments (DOE) assessment may be employed to run a minimum / maximum value to determine which stiffness / spring rate provides the best solution. The DOE assessment may include, but is not limited to, a range of material properties of the structural member 34 and other seat 24 components. Material tolerances, geometric variations, occupant position variations, and connection parts such as foam and trim may be considered in the assessment. The results of the variations are then used to determine the optimal stiffness value of the required structural member 34 in order to reduce the standard deviation and provide the desired performance. The number, geometry, and / or material of the additional connections may be considered. Depending on the results of the assessment, an increase or decrease in adjustable stiffness is achieved.

[0046] refer to Figure 6 , the embodiment shows a connecting rod 100 having a "Z" shaped cross section of segments 101-103. The connecting rod 100 is located in the slot cavity 69, the fastener 104 extends through the leg 72 and engages the segment 101, and the fastener 106 extends through the leg 70 and engages the segment 103. The segment 102 extends between the segments 101 and 103. In this embodiment, the fasteners 104, 106 are screwed into their respective segments 101, 103. The fastener 104 can be tightened to pull the segment 101 toward the leg 72, and can be loosened to allow the segment 101 to move away from the leg 72. The fastener 106 can be tightened to pull the segment 103 toward the leg 72, and can be loosened to allow the segment 103 to move away from the leg 70.

[0047] Increasing the torque on the fastener 104 and / or the fastener 106 increases the tension in the segment 102 of the connecting rod 100. Reducing the torque on the fastener 104 and / or the fastener 106 reduces the tension in the segment 102 of the connecting rod 100 or compresses the segment 102. Increasing the tension or compression in the segment 102 increases the stiffness of the structural member 34. Reducing the tension or compression in the segment 102 reduces the stiffness of the structural member 34. The connecting rod 100 can be a stamping, or in an embodiment, the segment 102 can be a cable or other structure in which the tension can be varied. Adjusting the tension / compression applied in the segment 102 adjusts the stiffness / spring rate of the selectively variable adjustable stiffness system 80.

[0048] Thus, adjustable stiffness systems and methods are able to tune structural members to achieve desired performance of a head restraint. Although at least one exemplary embodiment has been presented in the foregoing detailed description, it should be understood that a large number of variations exist. It should also be understood that the exemplary embodiment or multiple exemplary embodiments are merely examples and are not intended to limit the scope, applicability, or configuration of the present disclosure in any way. On the contrary, the foregoing detailed description will provide those skilled in the art with a convenient roadmap for implementing the exemplary embodiment or multiple exemplary embodiments. It should be understood that various changes may be made to the function and arrangement of elements without departing from the scope of the present disclosure as set forth in the appended claims and their legal equivalents.

Claims

1. A system with adjustable stiffness, the system comprising: Vehicle seats; a structural member of the vehicle seat, the structural member having a first wall and a second wall; a connecting rod extending between the first wall and the second wall, the connecting rod having a first section, a second section and a third section, wherein the second section extends between the first section and the third section; a first connector disposed between the first segment of the connecting rod and the first wall of the structural member; and a second connector disposed between the third section of the connecting rod and the second wall, Wherein at least one of the first connector and the second connector is adjustable to change the tension in the second section of the connecting rod and change the stiffness of the structural member.

2. The system according to claim 1, comprising: a head restraint for the vehicle seat coupled to the structural member; as well as A frame in a vehicle seat, wherein the structural member comprises a portion of the frame.

3. The system of claim 1, wherein: The structural member includes a channel forming a slot cavity, and The connecting rod is disposed in the groove cavity.

4. The system of claim 1, comprising a web and a third wall, wherein: The structural member includes a channel forming a slot cavity, the first wall comprising a first leg of the channel, said second wall comprising said web, said third wall comprising a second leg of said channel, The web extends between the first leg and the second leg to form a C-shape, and The connecting rod is connected to the first leg, the web and the second leg.

5. The system of claim 1, wherein: The vehicle seat has a backrest, and The structural member includes an upper cross member of the backrest.

6. The system of claim 1, comprising a head restraint on the vehicle seat, wherein: The at least one of the first connector and the second connector is configured to adjust the stiffness to balance a response of the head restraint to an expected force with a response of the head restraint to a resilient force.

7. The system according to claim 1, wherein: The connecting rod comprises a stamping and is arranged to extend along the structural member.

8. The system of claim 1, wherein: the structural member comprising a channel configured to provide the stiffness to the structural member, The structural member includes an angle extending from the channel and configured to increase the stiffness, and The connecting rod is configured to increase the stiffness.

9. A method for adjustable stiffness, the method comprising: constructing vehicle seats; In the vehicle seat, a structural member is included, the structural member having a first wall and a second wall; A connecting rod extends between the first wall and the second wall, the connecting rod having a first section, a second section and a third section, wherein the second section extends between the first section and the third section; adding a first connector between the first section of the connecting rod and the first wall of the structural member; adding a second connector between the third section of the connecting rod and the second wall; as well as Adjusting at least one of the first connector and the second connector changes the tension in the second section of the link and changes the stiffness of the structural member.

10. The method according to claim 9, comprising: including a head restraint on said vehicle seat; assessing a balance between an expected force on the head restraint and a rebound force from the head restraint; determining a baseline stiffness of the structural member based on evaluating the balance; creating a base design of the structural member to provide the baseline stiffness; adjusting the baseline stiffness with the link to provide a variable stiffness of the structural member; as well as The base design is reused in various applications requiring different stiffnesses provided by adjusting the baseline stiffness.

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