JP2013244872A - Seat back frame structure for vehicle seat - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide seat back frame structure for a vehicle seat which can suppress the stress concentration by moderating a change of the cross section of a boundary part between the lower part of a side frame of a seat back frame and the upper end of an upper arm.SOLUTION: An upper arm 52 of a reclining mechanism is fixed to the lower part of a side frame 40 of a seat back frame 21 forming a skeleton of a seat back of a vehicle seat. The upper end of the upper arm 52 is made high at the side on which a load acts, and formed into an inclined surface 56 or a curved surface that is gradually lowered toward at least the central part in the front and rear direction.

Description

  The present invention relates to a seat back frame structure for a vehicle seat.

Conventionally, an upper arm of a reclining mechanism is attached to a lower portion of a side frame portion of a seat back frame, which forms a skeleton portion of a seat back, with a fastening bolt or a weld to arrange the seat back so as to be adjustable with respect to a rear portion of a vehicle seat cushion. Fixed by.
Also, the side frame part of the seat back frame is formed in a bifurcated shape in the front and rear, and the upper arm is fixed by welding across the lower part between the first leg part on the front side and the second leg part on the rear side. A known seat back frame structure is known (see, for example, Patent Document 1).

German Utility Model Gazette DE 29816819U1

By the way, when the upper arm is fixed to the lower part of the side frame part of the seat back frame, an abrupt cross-sectional change occurs at the boundary part between the lower part of the side frame part and the upper end of the upper arm. And stress concentrates on the sudden cross-section change part of the side frame part lower part, and there exists a possibility that it may become easy to generate | occur | produce a damage.
Further, when the upper arm is fixed over the lower part between the first leg and the second leg of the bifurcated side frame, the first leg and the second leg are branched. The space from the upper part to the upper end of the upper arm is a space part.
For this reason, an abrupt cross-sectional change occurs at a boundary portion between the lower portion of the first leg and the second leg of the side frame portion and the upper end of the upper arm. Even in this case, there is a possibility that stress concentrates on the abrupt cross-sectional changes at the lower portions of the first leg and the second leg, and damage is likely to occur.

  In view of the above problems, an object of the present invention is to provide a seat for a vehicle seat that can suppress stress concentration by gradual cross-sectional change of a boundary portion between a lower portion of a side frame portion of a seat back frame and an upper end portion of an upper arm. It is to provide a back frame structure.

In order to solve the above-mentioned problems, a seat back frame structure for a vehicle seat according to claim 1 of the present invention is characterized in that a reclining mechanism is provided below a side frame portion of a seat back frame forming a skeleton part of a seat back of a vehicle seat. A seat back frame structure for a vehicle seat to which an upper arm is fixed,
An upper end of the upper arm is formed on an inclined surface or a curved surface that is high on a side on which a load acts and is gradually lowered toward at least a central portion in the front-rear direction.

According to the above configuration, the upper arm upper end of the reclining mechanism fixed to the lower portion of the side frame portion of the seat back frame has a high load acting side, and at least an inclined surface or a curved surface gradually lowered toward the front-rear direction central portion. Is formed.
For this reason, the cross-sectional change of the lower part of the side frame portion is moderated by the inclined surface or curved surface at the upper end of the upper arm, and stress concentration can be suppressed.
For example, if the vehicle seat is a front seat and the load of the seated person acting at the time of the rear impact of the vehicle is taken into consideration, the upper end of the upper arm is high on the front side where the seated person's load acts, and gradually decreases toward the rear side. It is desirable that the inclined surface or the curved surface be formed.
In addition, considering the load of the load (the load mounted in the luggage compartment behind the seat) that acts at the front of the vehicle, the upper seat of the upper arm is higher on the rear side where the load of the load acts. It is desirable to form an inclined surface or a curved surface gradually lowered toward the front side.
In addition, considering the load on the seater acting at the rear impact of the vehicle and the load of the load acting at the front impact of the vehicle, the upper end of the upper arm is higher at the front and rear sides and gradually lower toward the center in the front and rear direction. It is desirable to be formed in a V shape or U shape.

The vehicle seat back frame structure according to claim 2 is the vehicle seat back frame structure according to claim 1,
A flange portion bent in the sheet width direction is formed on the inclined surface or curved surface of the upper end of the upper arm.

  According to the said structure, the torsional rigidity of an upper arm can be improved with the flange part bent in the sheet | seat width direction by the inclined surface or curved surface of the upper end of an upper arm.

The seat back frame structure of the vehicle seat according to claim 3 is the seat back frame structure of the vehicle seat according to claim 1 or 2,
In the upper part of the upper arm, one or more through holes for weight reduction are formed along the inclined surface or curved surface,
Around the hole of the through hole, a cylindrical protrusion protruding on one side surface of the upper arm is formed by burring.

  According to the above configuration, the weight can be reduced by one or a plurality of through holes formed in the upper portion of the upper arm, and around the through holes by the cylindrical protrusions formed by burring around the through holes. Can be reinforced.

It is a perspective view which shows the seat back frame structure of the vehicle seat which concerns on Example 1 of this invention. It is a cross-sectional view which similarly shows the upper frame part of the seat back frame which follows the II-II line of FIG. It is a side view which expands and shows the state which similarly attached the upper arm of the reclining mechanism to the side frame part lower part. FIG. 4 is a plan sectional view of the upper arm along the line IV-IV in FIG. 3. It is a perspective view which similarly shows an upper arm from an inner side. It is a side view which shows the embodiment formed in the inclined surface where the rear side of the upper end of an upper arm is high and is gradually low toward the front side. FIG. 6 is a side view showing an embodiment in which the front and rear sides of the upper end of the upper arm are respectively high and formed in a V shape gradually lower toward the center in the front-rear direction.

  A mode for carrying out the present invention will be described in accordance with an embodiment.

A first embodiment of the present invention will be described with reference to the drawings.
As shown in FIG. 1, a seat back frame 21 that forms a skeleton part of a seat back of a vehicle seat is bent upward from both ends of the upper frame portion 30 and the upper frame portion 30 so as to have a predetermined interval in the seat width direction. Left and right side frame portions 40 separating the left and right side frames.

In the first embodiment, the seat back frame 21 is formed by an extruded product formed in a long and uniform cross-sectional shape such as an aluminum alloy.
As shown in FIG. 2, the seat back frame 21 includes a first component 22, a second component 25, and both the first and second components 22, 25 in the front-rear direction. And a connecting portion 28 that is connected at a predetermined interval.
The first component 22 includes a closed cross-sectional portion 23 having a substantially square hollow closed cross-section, and an open cross-section formed adjacent to the connecting portion 28 side of the closed cross-sectional portion 23 and partially opened (inside). And an open cross-sectional portion 24.
The second component 25 is adjacent to the closed cross-section 26 having a substantially trapezoidal hollow closed cross-section facing the closed cross-section 23 of the first component 22, and the connecting section 28 side of the closed cross-section 26. And an open cross-sectional portion 27 having an open cross-section that is partially formed (inner side facing the opening of the open cross-sectional portion 24 of the first component 22).

The upper frame portion 30 of the seat back frame 21 is arranged with the connecting portion 28 on the upper side, the first component portion 22 on the front side, and the second component portion 25 on the rear side.
Further, the first component portion 22 of the upper frame portion 30 is formed with notches 31 at predetermined intervals in the left-right direction, and a pair of left and right support holders 37 of the headrest device is welded to these notches 31 by welding or the like. It is fixed.

As shown in FIG. 1, the left and right side frame portions 40 are arranged with the connecting portion 28 on the outside, the first component portion 22 on the front side, and the second component portion 25 on the rear side.
Further, the side frame portion 40 is bent in the front-rear direction at a portion from the lower portion than the intermediate portion in the height direction, so that the side surface has a dogleg shape.
As shown in FIG. 1, a slit hole 41 is cut into the side frame portion 40 from the lower end of the connecting portion 28 to the vicinity of the upper end portion, and the first component portion 22 and the second component portion 25 are connected to the slit hole 41. Are opened in the front-rear direction to the angular position set as the branching portion 42.
The side frame portion 40 includes a first leg portion 44 on the front side constituted by the first component portion 22 (including the front side of the slit hole 41 of the connecting portion 28) and a second component portion 25 (the slit of the connecting portion 28). And a second leg portion 45 on the rear side that includes the rear side of the hole 41.

An upper arm 52 of a reclining mechanism is attached across the lower portion between the first leg portion 44 and the second leg portion 45 of the side frame portion 40.
In the first embodiment, the upper arm 52 is made of a steel plate, and, as shown in FIGS. 3 to 5, a flat portion 52a having a lower plate width dimension larger than an upper plate width dimension is formed at the center in the front-rear direction. A stepped curved portion 55 bent in a stepped shape toward the inside is formed on both front and rear sides of the flat portion 52a.

  As shown in FIGS. 3 to 5, the end portions of both stepped curved portions 55 of the upper arm 52 are from the longitudinal end portions of the first leg portion 44 and the second leg portion 45 (lower end portion in this embodiment 1). Engaging portions 53 and 54 each having a C-shaped cylindrical cross section that can be slidably engaged in the longitudinal direction (upward) and can be elastically reduced are formed.

  In the upper arm 52, the upper ends of both engaging portions 53 and 54 are connected to the first leg portion 44 (first constituent portion 22) and the second leg portion 45 (second constituent portion 25) of the side frame portion 40. Each of the open cross-sections 24 and 27 formed as receiving portions 24a and 27a is slid upward along the receiving portions 24a and 27a in a state of being engaged with the lower ends of the receiving portions 24a and 27a. As shown in FIG. 3, it is fixed at a set fixed position.

As shown in FIGS. 3 to 5, the upper end of the flat portion 52 a of the upper arm 52 is formed in an inclined or curved shape in which the direction in which the load acts is high and gradually lowered toward the opposite side.
In the first embodiment, the vehicle seat is a front seat, and the upper end of the upper arm 52 is set to It is formed on an inclined surface 56 (or curved surface) that is high on the front side where the load acts and gradually decreases toward the rear side.

In the first embodiment, as shown in FIGS. 3 and 5, a flange portion 57 bent in the seat width direction is formed on the inclined surface 56 (or curved surface) at the upper end of the upper arm 52.
In the first embodiment, a single (or a plurality of) through-holes 58 for reducing the weight are formed in a triangular shape along the inclined surface 56 (or curved surface) in the upper portion of the upper arm 52. Around the hole of the through hole 58, a cylindrical protrusion 59 protruding from one side surface (inner surface or outer surface) of the upper arm 52 is formed by burring.

  As shown in FIG. 3, a shaft hole 60 into which an operation shaft (not shown) of the reclining mechanism is inserted is formed below the flat portion 52 a of the upper arm 52, and along the outer periphery of the shaft hole 60. A plurality of fixing holes 61 for fixing components (not shown) of the reclining mechanism are formed.

The vehicle seat back frame structure according to the first embodiment is configured as described above.
Therefore, the upper end of the upper arm 52 is set at the upper end of the upper arm 52 in consideration of the load of the seated person acting on the first leg part 44 and the second leg part 45 forming the side frame part 40 of the seat back frame 21 at the time of the rear collision of the vehicle. It is formed on an inclined surface 56 (or curved surface) that is high on the front side (first leg portion 44 side) on which the load acts and gradually decreases toward the rear side (second leg portion 45 side).
For this reason, due to the inclined surface 56 at the upper end of the upper arm 52, the cross-sectional change of the lower part including the upper arm 52 in the first leg portion 44 of the side frame portion 40 becomes gentle.
As a result, it is possible to prevent stress from concentrating on the boundary portion between the upper end of the upper arm 52 below the first leg portion 44 of the side frame portion 40 and to prevent damage to the lower portion of the first leg portion 44 of the side frame portion 40. can do.

In the first embodiment, the torsional rigidity of the upper arm 52 can be increased by forming the flange portion 57 bent in the seat width direction with respect to the inclined surface 56 (or curved surface) at the upper end of the upper arm 52.
Further, in the first embodiment, the weight can be reduced by the single (or plural) through-holes 58 formed on the upper arm 52, and the cylindrical protrusion formed by burring around the through-hole 58. The portion 59 can reinforce the periphery of the through hole 58.

In addition, this invention is not limited to the said Example 1, In the range which does not deviate from the summary of this invention, it can implement with a various form.
For example, in the first embodiment, the vehicle seat is the front seat, and the upper end of the upper arm 52 is higher on the front side and gradually toward the rear side in consideration of the load on the seated person acting at the time of the rear collision of the vehicle. However, the present invention is not limited to this.

  For example, considering the load of a load (a load mounted in a luggage compartment behind the seat) that acts when the vehicle seat is a rear seat and the vehicle seat is a front seat, as shown in FIG. The rear side (second leg 45 side) of the side frame part 40 to which the load acts is high, and is formed on an inclined surface or a curved surface gradually lowered toward the front side (first leg part 44). desirable. Even in this case, it is desirable that a flange portion 157 bent in the seat width direction is formed on the inclined surface 156 (or curved surface) at the upper end of the upper arm 152. Further, a single (or a plurality of) through-holes 158 for weight reduction are formed in the upper portion of the upper arm 152, and a cylinder projecting to one side surface (inner side surface or outer side surface) of the upper arm 152 around the through hole 158. It is desirable that the protrusion 159 is formed by burring.

Further, considering the load of the seated person that acts at the time of the rear collision of the vehicle and the load of the load that acts at the time of the front collision of the vehicle, the upper end of the upper arm 252 is the front and rear sides of the side frame portion 40 as shown in FIG. It is desirable that each of the first leg portion 44 and the second leg portion 45 is high and is formed in a V shape or a U shape that is gradually lowered toward the central portion in the front-rear direction. Even in this case, it is desirable that a flange portion 257 bent in the sheet width direction is formed on the inclined surface 256 (or curved surface) at the upper end of the upper arm 252. Further, a single (or a plurality of) through-holes 258 for weight reduction are formed in the upper part of the upper arm 252, and the cylinder protrudes to one side surface (inner side surface or outer side surface) of the upper arm 252 around the hole of the through hole 258. It is desirable that the protrusion 259 is formed by burring.
In the first embodiment, the case where the side frame portion 40 of the seat back frame 21 is formed in a bifurcated shape having the first leg portion 44 and the second leg portion 45 at the front and rear is illustrated. This invention can be implemented even when 40 is formed of a panel material (pressed product of a steel plate).

21 Seat back frame 40 Side frame portion 44 First leg portion 45 Second leg portion 52 Upper arm 56 Inclined surface (inclined surface or curved surface)
57 Flange part 58 Through hole 59 Cylindrical protrusion

Claims (3)

A seat back frame structure for a vehicle seat in which an upper arm of a reclining mechanism is fixed to a lower portion of a side frame portion of a seat back frame forming a skeleton part of a seat back of a vehicle seat,
A seat back frame structure for a vehicle seat, wherein an upper end of the upper arm is formed on an inclined surface or a curved surface that is high on a side on which a load acts and is gradually lowered toward at least a central portion in the front-rear direction. The vehicle seat back frame structure according to claim 1,
A seat back frame structure for a vehicle seat, wherein a flange portion bent in a seat width direction is formed on an inclined surface or a curved surface at an upper end of an upper arm. The vehicle seat back frame structure according to claim 1 or 2,
In the upper part of the upper arm, one or more through holes for weight reduction are formed along the inclined surface or curved surface,
A seat back frame structure for a vehicle seat, wherein a cylindrical protrusion protruding from one side surface of the upper arm is formed around the through hole by burring.

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