Vehicle seat with walk-in mechanism

Abstract

The purpose of the present invention is to provide, in a vehicle seat having a walk-in mechanism, a locking mechanism for a seat back with which rotation of a lock plate can be suppressed against impact in any direction, and with which the locked state can be more reliably retained. In order to achieve the foregoing, provided is a vehicle seat having a walk-in mechanism, wherein: a reclining unit having the walk-in mechanism comprises a swing plate and latch for locking a seat back at a seated posture position; the latch has a structure that rotates about a latch rotating shaft, locks rotation of the seat back by meshed engagement with the swing plate, and releases the lock when the meshed engagement with the swing plate comes out; and the latch is given a structure with which a counter plate is added to the opposite side from the position of meshed engagement with the swing plate, relative to the latch rotating shaft, and the center-of-gravity position of the latch is brought close to the center of rotation of the latch.

Claims

1. A vehicle seat with a walk-in mechanism, comprising: a reclining unit that includes the walk-in mechanism, wherein the reclining unit includes a swing plate and a latch for locking a seat back at a seating posture position, the seat back has a lever connected to the latch at a shoulder, the latch is disposed closer to the lever than the swing plate is to the lever, the latch has a structure that turns about a latch rotation shaft, locks the turning of the seat back by engaging with the swing plate, the latch is lifted by pulling up the lever connected to the latch, and releases the lock by disengaging from the swing plate, and the latch has a structure in which a counter plate is added on an opposite side of a position where the latch engages with the swing plate with respect to the latch rotation shaft and on an opposite side of a side where the lever is connected so that a position of a center of gravity of the latch is close to a rotational center of the latch.

2. The vehicle seat with the walk-in mechanism according to claim 1, wherein the counter plate is integral with the latch.

3. The vehicle seat with the walk-in mechanism according to claim 1, wherein the counter plate is made of a material different from a material of the latch.

4. The vehicle seat with the walk-in mechanism according to claim 1, wherein the latch has a hole for weight reduction.

5. The vehicle seat with the walk-in mechanism according to claim 1, wherein the position of the center of gravity of the latch approximately matches the rotational center of the latch.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 includes structural drawings of a vehicle seat with a walk-in mechanism and a reclining unit according to an example.

(2) FIG. 2 includes explanatory drawings of an effect of a latch used in a lock mechanism of a seat back according to the example.

(3) FIG. 3 includes explanatory drawings of a walk-in mechanism of a vehicle seat with the walk-in mechanism according to a conventional example.

DESCRIPTION OF EMBODIMENTS

(4) The following describes an example of the present invention with reference to the drawings.

EXAMPLE

(5) First, a description will be given of a conventional vehicle seat with a walk-in mechanism as a prerequisite of the present invention. FIG. 3 includes explanatory drawings of the walk-in mechanism of the vehicle seat with the walk-in mechanism according to the conventional example. (A) illustrates a front perspective external view of the vehicle seat. A vehicle seat 1 includes a seat cushion 2 and a seat back 3. (B) illustrates a side view of the vehicle seat 1. The seat back 3 includes a lever 4 on its shoulder. The seat back 3 includes, what is called, the walk-in mechanism. The walk-in mechanism enables to release a lock of the seat back 3 by pulling the lever 4 upward to instantaneously make the seat back 3 fall forward such that, for example, an occupant on a rear seat can get in and out. (C) is a schematic configuration diagram for describing the walk-in mechanism. A reclining unit 5 including the walk-in mechanism is secured to the seat cushion 2 and the seat back 3, and is configured such that the seat back 3 turns about a coupling shaft with respect to the seat cushion 2. The reclining unit 5 includes a swing plate 6 and a latch 7 for locking the seat back 3 at a seating posture position. The latch 7 turns about a latch rotation shaft 8 and engages with the swing plate 6 via a meshing portion 9 to act to lock the turning of the seat back 3. The latch 7 is coupled to the lever 4 via a cable 10. Pulling the lever 4 upward pulls the latch 7 upward to disengage the latch 7 from the swing plate 6, and thus, the lock is released.

(6) Here, the center of gravity of the latch 7 is positioned at a position indicated by a black circle in the drawing. In some cases, for example, a collision from a vehicle collision floats the latch by an inertia force, and releases the lock.

(7) Accordingly, this example is configured such that the position of the center of gravity of the latch is brought close to a rotational center of the latch in order to solve the above-described problems. The following describes the example with reference to the drawings.

(8) FIG. 1 includes structural drawings of a vehicle seat with a walk-in mechanism and a reclining unit according to the example. In FIG. 1, (A) illustrates a frame structure of the vehicle seat 1. The reclining unit 5 is secured to a cushion side frame of the seat cushion 2 and a back side frame of the seat back 3. The seat back 3 is configured to turn about a coupling shaft with respect to the seat cushion 2.

(9) FIG. 1(B) is a drawing that enlarges the reclining unit 5 enclosed in a circular dotted line in FIG. 1(A). FIG. 1(B) is different from the conventional example in FIG. 3(C) in that a counter plate 11 is added on the latch 7. That is, it is a structure in which the counter plate 11 is added to increase a weight on an opposite side of a side where the lever 4 of the latch 7 is coupled with respect to the latch rotation shaft 8 such that the position of the center of gravity of the latch 7 is brought close to the latch rotational center. In other words, it is a structure in which the latch 7 has the counter plate 11 added on the opposite side of the meshing portion 9 engaging with the swing plate 6 with respect to the latch rotation shaft 8 such that the position of the center of gravity of the latch 7 is brought close to the rotational center of the latch 7. This ensures the reduced generated torque in a lock off direction of the latch during a collision. The following describes the detail.

(10) FIG. 2 includes drawings describing an effect of the latch used for the lock mechanism of the seat back according to the example. In FIG. 2, (A) illustrates the latch 7 of the conventional example and (B) illustrates the latch 7 of the example. Here, a torque generated in the latch 7 by the inertia force due to, for example, a vehicle collision is obtained from the following formula (1)
Generated torque=latch weightposition of center of gravity from rotational center (1)

(11) That is, it is a value obtained by multiplying a distance from the rotational center of the latch to the position of the center of gravity of the latch by the latch weight. In FIG. 2, the respective latch rotational centers are indicated by +, and the respective positions of the center of gravity are indicated by black circles. The respective distances from the rotational centers to the positions of the center of gravity of the latches are indicated by a in the conventional example and b in this example as illustrated. Then, adding the counter plate 11 in this example ensures bringing the position of the center of gravity close to the rotational center, thereby ensuring a relationship of a>b. Accordingly, the torque generated in the latch 7 by the inertia force due to the vehicle collision can be reduced.

(12) That is, for all the direction including an impact in a vertical direction thrusting upward by a vehicle floor broken in a vehicle collision and an impact in a front-rear direction, a rotating torque generated in the latch by the inertia force can be reduced. Therefore, the lock state can be further reliably retained.

(13) It should be noted that, while in FIG. 2(B), the position of the center of gravity of the latch is displaced off from the rotational center, it is more preferable when they match.

(14) Integrating the counter plate 11 with the latch 7 ensures reducing the number of components. The counter plate 11 may be made of a material with a heavy specific gravity, such as lead, by considering an issue of a space. The torque generated by the inertia force is proportionate to the latch weight, and therefore, a hole may be made for a weight reduction after ensuring strength.

(15) As described above, this example is configured such that the position of the center of gravity of the latch is brought close to the rotational center of the latch. This ensures providing the vehicle seat with the walk-in mechanism including the lock mechanism of the seat back that ensures reducing the torque of the latch by the inertia force generated due to a collision or the like so as to further reliably retain the lock state against the impacts from any directions.

(16) While the example has been described above, the present invention is not limited to the above-described examples, and includes various modifications. The above-described examples are described in detail for simply describing the present invention, and do not necessarily include all the described configurations. A part of the configurations of the example can be replaced by the configuration of another example.

REFERENCE SIGNS LIST

(17) 1 . . . vehicle seat, 2 . . . seat cushion, 3 . . . seat back, 4 . . . lever, 5 . . . reclining unit, 6 . . . swing plate, 7 . . . latch, 8 . . . latch rotation shaft, 9 . . . meshing portion, 10 . . . cable, 11 . . . counter plate.