Abstract: A seat slide device includes lower rails and upper rails both formed substantially symmetrical bilaterally across a center in a width direction, and lock mechanisms on both sides of the upper rails to be engaged with the lower rails to lock them. An entire structure combining the lower rails, the upper rails and the lock mechanisms is substantially symmetrical forward, backward, and bilaterally, and a force applied to the lower rails and the upper rails can be absorbed substantially evenly forward, backward, and left and right. Since the lock mechanisms have an elastic lock member in a substantially center part in a longitudinal direction, the lower rails and the upper rails are elastically deformable for reduction of a biased load at a time of locking, improvement in vibration absorption characteristic, and the like, and a plate thickness of each material can be made thinner than conventional for weight reduction.

Abstract: A predetermined component such as a recliner is attached to a long member in advance, and thereafter by bending the long member, a pair of side frames and an upper frame are integrally formed. Therefore, the recliner can be attached to the long member not bent yet and thus in a substantially flat state, and in addition, the pair of side frames and the upper frame can be integrally formed, which does not require labor and contributes to a reduction in manufacturing cost. Moreover, by adjusting a position where the bending is performed, it is possible to manufacture seat frame structures different in dimension even if the long members not bent yet have the same length, and from this viewpoint as well, it is possible to reduce labor and manufacturing cost.

Abstract: A vehicle seat suitable for weight reduction. A left and right side frames constituting a cushion frame unit are constituted of plate-shaped frames which are long in a forward and backward direction and formed of a thin material made of metal with a predetermined thickness or less, a plurality of beams are bridged across the side frames, and moreover, one or both of the side frames is or are supported on a seat slide device via a truss support part. In other words, the side frames disposed in a direction substantially orthogonal to the plurality of beams serve the role of stringers, and as a result, rigidity in the forward and backward direction of the side frames in particular is high rigidity of a predetermined value or more even if they are made of a thin material, and they can be reduced in weight.

Abstract: A vibration mode control method for a thin plate-reinforcement structure utilizes a reinforcing effect of a weld bead, wherein the thin plate-reinforcement structure comprises two welded components at least one of which includes a thin plate portion. After a first (thin plate) component and a second (another) component are arc-welded discontinuously at several positions, a stress direction and level in one of the resulting weld areas located to be subject to stress concentration is preliminarily verified. Then, a stress-dispersing weld bead (f) is laid to extend between the weld area which is an area subject to stress concentration and the first (thin plate) component, wherein the stress-dispersing weld bead (f) is set to a direction and length capable of preventing fatigue crack from occurring in the first (thin plate) component.

Abstract: A vehicle seat suitable for weight reduction. A left and right side frames constituting a cushion frame unit are constituted of plate-shaped frames which are long in a forward and backward direction and formed of a thin material made of metal with a predetermined thickness or less, a plurality of beams are bridged across the side frames, and moreover, one or both of the side frames is or are supported on a seat slide device via a truss support part. In other words, the side frames disposed in a direction substantially orthogonal to the plurality of beams serve the role of stringers, and as a result, rigidity in the forward and backward direction of the side frames in particular is high rigidity of a predetermined value or more even if they are made of a thin material, and they can be reduced in weight.

Abstract: A seat slide device includes lower rails and upper rails both formed substantially symmetrical bilaterally across a center in a width direction, and lock mechanisms on both sides of the upper rails to be engaged with the lower rails to lock them. An entire structure combining the lower rails, the upper rails and the lock mechanisms is substantially symmetrical forward, backward, and bilaterally, and a force applied to the lower rails and the upper rails can be absorbed substantially evenly forward, backward, and left and right. Since the lock mechanisms have an elastic lock member in a substantially center part in a longitudinal direction, the lower rails and the upper rails are elastically deformable for reduction of a biased load at a time of locking, improvement in vibration absorption characteristic, and the like, and a plate thickness of each material can be made thinner than conventional for weight reduction.

Abstract: A vibration mode control method for a thin plate-reinforcement structure utilizes a reinforcing effect of a weld bead, wherein the thin plate-reinforcement structure comprises two welded components at least one of which includes a thin plate portion. After a first (thin plate) component and a second (another) component are arc-welded discontinuously at several positions, a stress direction and level in one of the resulting weld areas located to be subject to stress concentration is preliminarily verified. Then, a stress-dispersing weld bead (f) is laid to extend between the weld area which is an area subject to stress concentration and the first (thin plate) component, wherein the stress-dispersing weld bead (f) is set to a direction and length capable of preventing fatigue crack from occurring in the first (thin plate) component.