CROSS REFERENCE TO RELATED APPLICATION

This application claims priority to Japanese Patent Application No. 2019-003104, filed on Jan. 11, 2019, which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

The present disclosure particularly relates to a lower structure of a vehicle in which a battery pack is disposed under a seat.

BACKGROUND

In a hybrid vehicle or an electric vehicle using a rotary electric machine as a drive source, a battery pack is mounted as a power source. For example, in JP 2016-199105 A, a battery pack is mounted under a rear seat and on a floor panel.

The battery pack, which is a heavy load, is supported by a frame member of a vehicle. For example, referring toFIG. 7, a front end of a battery pack500is supported by a floor cross member510that is a frame member. A rear end of the battery pack500is supported by a battery bracket520.

Moreover, a front end of a rear seat540is supported by the floor cross member510through a seat front bracket550. A rear end of the rear seat540is fixed to a rear floor panel530through a seat rear bracket560.

A seat belt mechanism is attached to the rear seat540. The seat belt mechanism includes webbing that is a so-called belt part, and an anchor that supports the webbing on a vehicle body. Referring toFIG. 7, for example, a three-point seat belt mechanism includes a shoulder anchor (not shown) provided above a pillar and supporting one end (the upper end) of webbing630, and two floor anchors640,650provided at both respective in a vehicle width direction of a waist portion of the webbing630(waist belt part). One floor anchor640supports another end (the lower end) of the webbing630. The other floor anchor650supports a buckle610into which a tongue660attached to the webbing630is to be inserted.

The floor anchors640,650are fastened to a seat rail670that is a frame member provided on a seat cushion540A of the rear seat540. Further, the seat rail670is fastened to the rear floor panel530through the seat rear bracket560.

Incidentally, various safety standards are specified for seat belt mechanisms. For example, the belt anchor mechanisms including shoulder anchors and floor anchors, safety standards for strength and so on are specified.

For example, according to Regulation 14 specified by the United Nations Economic Commission for Europe (UN/ECE), as a so-called belt anchor test, a crash test dummy is placed on a seat and restrained with a seat belt, and then a speed fluctuation (acceleration and deceleration) of 50 km/h or more is applied. Furthermore, angular displacement of the belt anchor mechanism when the speed fluctuation is applied is measured. For example, when the angular displacement of the floor anchor is within 10°, it is determined that a safety standard is satisfied.

Here, referring toFIG. 8, in the belt anchor test, when the crash test dummy is restrained with the webbing630at the time of an abrupt stop, a tensile load toward the front of the vehicle is applied to the seat rear bracket560via the buckle610and the floor anchor650. At this time, the rear floor panel530to which a lower surface of the seat rear bracket560is fastened is lifted up and deformed as indicated by a broken line, and, as a result, the angle of the floor anchor650may be displaced.

In order to restrain the angular displacement of the floor anchor650, it is conceivable to increase the rigidity of the seat rear bracket560and the rear floor panel530to which the seat rear bracket560is fastened, but there is a possibility of causing an increase in the cost and weight of the vehicle.

Accordingly, it is an advantage of the present disclosure to provide a vehicle lower structure capable of restraining the angular displacement of the belt anchor mechanism when a load is input, while restraining an increase in the coat and weight of the vehicle.

SUMMARY

The present disclosure relates to a vehicle lower structure including: a battery pack disposed on a floor panel; and a seat disposed on the battery pack. In the vehicle lower structure, a floor anchor for supporting a waist portion of webbing of a seat belt mechanism is supported by a frame member of a seat cushion of the seat. The frame member of the seat cushion is supported by the floor panel through a holding member. Further, an end portion of the battery pack is also supported by the floor panel through the holding member.

According to the above configuration, when a tensile load toward the front of the vehicle is input to the floor anchor, the same tensile load is also input to the holding member that holds the floor anchor. At this time, since the battery pack is also supported by the holding member, lifting of the holding member is restrained by the weight of the battery pack. As a result, it is possible to restrain the angular displacement of the belt anchor mechanism at the time of input of a load without needing to increase the rigidity of the holding member and the floor panel. Moreover, according to the above configuration, holding members for the floor anchor and the battery pack which are provided separately in a conventional structure are made one structure, and therefore an increase in the cost and weight of the vehicle can be restrained.

In the above disclosure, the holding member may extend in a vehicle width direction. In this case, the holding member has a plurality of seat support points for supporting the frame member of the seat cushion, and a plurality of battery support points for supporting an end portion of the battery pack, which are formed alternately along the vehicle width direction. Further, the separation distance between each of the seat support points and the corresponding battery support point is equal throughout the plurality of the seat support points and a plurality of the battery support points.

According to the above configuration, when a tensile load is input to the seat support point, the tensile load is evenly distributed to the battery support points arranged equal intervals.

According to the present disclosure, it is possible to restrain the angular displacement of the belt anchor mechanism when a load is input, while restraining an increase in the cost and weight of the vehicle.

