Vehicle rear portion structure

A vehicle rear portion structure includes an upper back and an upper back reinforcement. The upper back reinforcement is made of a material different from the upper back and is provided to extend in a vehicle width direction on an upper side of a rear portion of the upper back in a vehicle front-rear direction. The upper back reinforcement includes a front flange, a rear flange, a bulging portion, and a luggage opening flange. Luggage weather rubber is attached to the luggage opening flange. The upper back is joined to the rear flange of the upper back reinforcement at a rear end portion of the upper back in the vehicle front-rear direction by any of caulking joining, bolt joining, and rivet joining. A rear side joining portion is covered with the luggage weather rubber.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Japanese Patent Application No. 2017-223371 filed on Nov. 21, 2017, which is incorporated herein by reference in its entirety including the specification, drawings and abstract.

BACKGROUND

1. Technical Field

The present disclosure relates to a vehicle rear portion structure.

2. Description of Related Art

Japanese Unexamined Patent Application Publication No. 2017-043129 (JP 2017-043129 A) discloses a technique for joining dissimilar metals in a case where an upper back is made of aluminum, a rear skeleton provided in the rear end portion of the upper back is made of iron (made of steel), and the upper back and the rear skeleton are joined to each other. By the upper back being made of aluminum, vehicle weight reduction can be achieved as compared with a case where the upper back is made of iron.

For an increase in weight reduction rate based on the use of the dissimilar material of the upper back (use of aluminum), it is desirable that an upper back2is provided to extend rearward up to a luggage opening6(including the vicinity of the luggage opening) as illustrated inFIG. 4. However, a part connected to the luggage opening6is a rain gutter portion (water flow surface)6athat can be seen when a user U opens a luggage door7. Although dissimilar material joining techniques for joining dissimilar materials include caulking joining, bolt joining, and rivet joining, the caulking joining pushes out the material and the bolt joining and the rivet joining are performed by secondary materials being used, and thus these methods may conspicuously result in a joining place having a projecting shape or a large joining portion diameter compared to spot welding in which base materials are melted and joined.

Accordingly, in a case where the upper back2is provided to extend rearward up to the luggage opening6, the dissimilar material joining portion between the upper back2and a surrounding member may be seen from the user U when the luggage door7is open, which may cause a poor appearance.

SUMMARY

The present disclosure provides a vehicle rear portion structure with which the design at a time when a luggage door is open can be further improved even in a case where an upper back is provided to extend rearward up to a luggage opening.

An aspect of the disclosure relates to a vehicle rear portion structure. The vehicle rear portion structure includes an upper back and an upper back reinforcement. The upper back reinforcement is made of a material different from the upper back and is provided to extend in a vehicle width direction on an upper side of a rear portion of the upper back in a vehicle front-rear direction. The upper back reinforcement includes a front flange, a rear flange behind the front flange in the vehicle front-rear direction, a bulging portion provided to bulge upward between the front flange and the rear flange, and a luggage opening flange provided to rise upward from a rear end portion of the rear flange in the vehicle front-rear direction and define an opening edge on a front side of a luggage room. Luggage weather rubber is provided continuously over an entire circumference of the opening edge of the luggage room, and is attached to the luggage opening flange. The upper back is joined to the front flange of the upper back reinforcement at an intermediate portion of the upper back in the vehicle front-rear direction by any of caulking joining, bolt joining, and rivet joining and is joined to the rear flange of the upper back reinforcement at a rear end portion of the upper back in the vehicle front-rear direction. A rear side joining portion as a joining portion between the upper back and the rear flange of the upper back reinforcement is covered with the luggage weather rubber. In the vehicle rear portion structure according to the aspect of the disclosure, the luggage weather rubber may include an attachment portion attached to the luggage opening flange of the upper back reinforcement and a lip extending from the attachment portion in a direction to enlarge an opening of the luggage room. The rear side joining portion may be covered with the lip of the luggage weather rubber. In the vehicle rear portion structure according to the aspect of the disclosure, a length of the lip from the attachment portion in a cross-sectional view of the luggage weather rubber may be constant over an entire circumference of the luggage weather rubber. In the vehicle rear portion structure according to the aspect of the disclosure, the length of the lip from the attachment portion may be equal to or greater than a length at which the lip reaches a vehicle front side end of the rear side joining portion and may be equal to or less than a length at which the lip reaches the bulging portion in a vehicle width direction center portion of the opening edge on the front side of the luggage room. In the vehicle rear portion structure according to the aspect of the disclosure, the upper back reinforcement may include reinforcement outside portions outside vehicle width direction ends of the upper back in the vehicle width direction in both end portions in the vehicle width direction. The upper back reinforcement may be joined by spot welding to a vehicle body member made of the same type of material as the upper back reinforcement in the reinforcement outside portion. In the vehicle rear portion structure according to the aspect of the disclosure, a plurality of the rear side joining portions covered with the luggage weather rubber may be provided in the vehicle width direction. An end of the upper back in the vehicle width direction may be between an outermost side joining portion on an outermost side in the vehicle width direction among the rear side joining portions and an adjacent spot joining portion provided at a position not covered with the luggage weather rubber at a position adjacent to the outermost side joining portion in the vehicle width direction among spot joining portions between the reinforcement outside portion and the vehicle body.

The following effects can be achieved from the aspect of the disclosure. Since the upper back is joined to the rear flange as well as the front flange of the upper back reinforcement, the upper back is provided to extend rearward up to the luggage opening (including the vicinity of the luggage opening). As a result, the weight reduction rate in a case where the upper back is made of a material lighter than the material of the upper back reinforcement can be maximized rearward unlike in a case where the upper back is joined to the front flange of the upper back reinforcement without being joined to the rear flange.

Since the rear side joining portion, which is the joining portion between the upper back and the rear flange of the upper back reinforcement, is covered with the luggage weather rubber, the rear side joining portion being seen when the luggage door is open can be suppressed. Accordingly, even in a case where the upper back is provided to extend rearward up to the luggage opening, the design at a time when the luggage door is open can be further improved.

Since the rear side joining portion is covered with the luggage weather rubber, a new part such as a garnish merely for covering and hiding the rear side joining portion is unnecessary. Accordingly, unlike in a case where a new part is added, an increase in the number of parts can be further suppressed, which is advantageous in terms of cost.

According to the aspect of the disclosure, since the rear side joining portion is covered also with the lip of the luggage weather rubber, it is possible to cover the rear side joining portion with a simple configuration as compared with a case where the rear side joining portion is covered with the attachment portion of the luggage weather rubber.

According to the aspect of the disclosure, since the length of the lip extending from the attachment portion in the cross-sectional view of the luggage weather rubber is constant over the entire circumference of the luggage weather rubber, the luggage weather rubber can be inexpensively manufactured as compared with a case where the length of the lip is different.

The following effects are also achieved through the aspect of the disclosure. It is desirable that the opening of the luggage room is large in view of improving the usability of the luggage room. Accordingly, it is desirable that the length of the rear flange of the upper back reinforcement in the vehicle front-rear direction is short, and the length is minimized in the vehicle width direction center portion of the opening edge on the front side of the luggage room. In the disclosure, the length of the lip extending from the attachment portion is set based on the vehicle width direction center portion of the opening edge on the front side of the luggage room, that is, the part where the length of the rear flange of the upper back reinforcement in the vehicle front-rear direction is minimized and is equal to or greater than the length at which the lip reaches the vehicle front side end of the rear side joining portion and equal to or less than the length at which the lip reaches the bulging portion. Accordingly, across the entire vehicle width direction area of the upper back reinforcement, (i) it is possible to further suppress the lip abutting against the bulging portion of the upper back reinforcement to be bent and cause a poor appearance and (ii) it is possible to further suppress the necessity of displacing the opening edge on the front side of the luggage room to the rear side of the vehicle in order to ensure a disposition space for the lip.

According to the aspect of the disclosure, since the upper back reinforcement is joined by spot welding to the vehicle body member made of the same type of material as the upper back reinforcement in the reinforcement outside portion, the design can be further improved unlike in a case where joining is performed by caulking joining, bolt joining, or rivet joining, which are joining methods for dissimilar materials.

According to the aspect of the disclosure, the end of the upper back in the vehicle width direction is between the outermost side joining portion, which is on the outermost side in the vehicle width direction among the rear side joining portions, and the adjacent spot joining portion, which is provided at a position that is not covered with the luggage weather rubber, and which is adjacent to the outermost side joining portion among the spot joining portions between the reinforcement outside portion and the vehicle body. Accordingly, the vehicle width direction end of the upper back can be set at the outermost side position where the rear side joining portion can be covered with the luggage weather rubber. Accordingly, in a case where the rear side joining portion is covered with the luggage weather rubber, the weight reduction rate in a case where the upper back is made of a material lighter than the material of the upper back reinforcement can be maximized in the vehicle width direction.

DETAILED DESCRIPTION OF EMBODIMENTS

Hereinafter, a vehicle rear portion structure10according to an example of the disclosure will be described with reference to accompanying drawings. In the drawings, UP indicates upward, FR indicates the front of a vehicle, and OUT indicates the outside in a width direction of the vehicle. Unless otherwise noted, the upper-lower direction and the front-rear direction in the following description indicate the upper-lower direction and the front-rear direction of the vehicle, respectively.

As illustrated inFIG. 1, the vehicle rear portion structure10according to the example of the disclosure has an upper back20, an upper back reinforcement (hereinafter, also referred to as an upper back R/F)30, a side member sub-assembly (hereinafter, also referred to as a side member S/A)40, and luggage weather rubber50.

The upper back20is a body part that partitions a luggage room60and the inside of the vehicle cabin mainly in the upper-lower direction behind the rear seat (not illustrated) of the vehicle. The upper back20is a plate-shaped body that has a thickness direction corresponding to the upper-lower direction and is formed in a substantially rectangular shape in plan view.

The upper back20is joined to the upper back R/F30in a rear portion21. The rear portion21of the upper back20is a part behind the center of the upper back20in the front-rear direction. For example, the rear portion21is a rear end portion21bof the upper back20in the front-rear direction and the vicinity of the rear end portion. End portions22of the upper back20in the vehicle width direction are joined to the right and left side member S/As40, respectively. A front end portion23of the upper back20is joined to a room partition panel (not illustrated), which is a body part that partitions the luggage room60and the inside of the vehicle cabin mainly in the front-rear direction.

Vehicle width direction ends24of the upper back20in plan view are vehicle width direction positions that are the same or nearly the same across the entire front-rear direction area of the upper back20. Still, the vehicle width direction positions of the vehicle width direction ends24of the upper back20in plan view may also be different in the front-rear direction of the upper back20.

The upper back R/F30is provided to extend in the vehicle width direction on the upper side of the rear portion21of the upper back20. The upper back R/F30is manufactured by a plate-shaped body being folded and bent by molding. As illustrated inFIG. 2, the upper back R/F30has a front flange31, a rear flange32behind the front flange31, a bulging portion33bulging upward between the front flange31and the rear flange32in the front-rear direction, and a luggage opening flange34rising upward from the rear end portion of the rear flange32and forming an opening edge61on the front side of the luggage room60.

The front flange31is joined to a front-rear direction intermediate portion21aof the upper back20. The rear flange32is joined to the rear end portion21bof the upper back20in a plurality of places in the vehicle width direction. The upper surface of the rear flange32is a front rain gutter portion (water flow surface)32athat can be seen when a user opens a luggage door70. Since the upper back20is joined to the rear flange32as well as the front flange31of the upper back R/F30, the upper back20is provided to extend rearward up to the opening of the luggage room60(including the vicinity of the opening of the luggage room). In other words, the upper back20being provided to extend rearward up to the opening of the luggage room60means that the upper back20is provided to extend to the rear flange32of the upper back R/F30.

The bulging portion33has a top plate33aat a distance above the upper back20, a front wall33bextending downward from the front end of the top plate33ato the rear end of the front flange31, and a rear wall33cextending downward from the rear end of the top plate33ato the front end of the rear flange32. Since the upper back R/F30has the bulging portion33, a closed cross section portion120, which is a closed cross section in a sectional view orthogonal to the vehicle width direction, is formed by the upper back R/F30and the rear portion21of the upper back20and the rigidity of the vehicle rear portion structure10is enhanced.

Back window glass100of the vehicle is placed on the top plate33aof the bulging portion33. A rear end portion101of the back window glass100is placed on the top plate33aand bonded by an adhesive102. A through hole33dpenetrating the top plate33ain the upper-lower direction is formed in the top plate33aof the bulging portion33. The through hole33dis formed in front of the position where the adhesive102is provided. A rear end portion111of an interior material110of the vehicle covering the upper back20from above and below the back window glass100is inserted in the through hole33d. The interior material110is held by the bulging portion33in a state where the rear end portion111is inserted in the through hole33d.

As illustrated inFIG. 1, the upper back R/F30has a reinforcement outside portion35in each end portion in the vehicle width direction. The reinforcement outside portion35is outside the vehicle width direction end24of the upper back20in the vehicle width direction. The upper back R/F30is joined to the side member S/A40in the reinforcement outside portion35.

The side member S/A40rises upward from each side portion of a floor body80of the vehicle in the vehicle width direction and constitutes the right and left side portions of the body of the vehicle. The rear end portions of the right and left side member S/As40are joined to a lower back90extending in the vehicle width direction and forming an opening edge63on the rear side of the luggage room60. The side member S/A40has a bracket package41to which the end portion22of the upper back20in the vehicle width direction is joined after being placed and a trough42behind the bracket package41. The reinforcement outside portion35is joined to the trough42.

The end of the trough42on the luggage room60side forms a vehicle width direction side opening edge62of the luggage room60. The upper surface of the trough42is a side rain gutter portion (water flow surface)42athat can be seen when a user opens the luggage door70. The side rain gutter portion42ais linked to the front rain gutter portion32aof the upper back R/F30, and rainwater or the like flowing through the front rain gutter portion32aflows from the front rain gutter portion32ainto the side rain gutter portion42aand flows rearward (downward) through the side rain gutter portion42a. Then, the rainwater or the like flows from the rear end portion (lower end portion) of the side rain gutter portion42aor to the lower back90and flows out of the vehicle.

The upper back20is made of a material different from the surrounding parts joined to the upper back20. In other words, the upper back20is made of a material different from the upper back R/F30, the side member S/A40, and the room partition panel (not illustrated). Specifically, the upper back R/F30, the side member S/A40, and the room partition panel are made of iron (made of steel) and the upper back20is made of a material lighter than iron for vehicle weight reduction. For example, the upper back20is made of aluminum (aluminum alloy). Alternatively, the upper back20may be made of magnesium (magnesium alloy) or resin such as fiber reinforced plastic (FRP) and carbon fiber reinforced plastic (CFRP).

Since the material of the upper back20differs from the material of the upper back R/F30, the side member S/A40, and the room partition panel, the melting point of the upper back20differs from the melting point of the upper back R/F30, the side member S/A40, and the room partition panel. As a result, it is difficult to use spot welding in which base materials are melted and joined. Accordingly, joining between the upper back20and the upper back R/F30, the side member S/A40, and the room partition panel is performed by caulking joining, bolt joining, or rivet joining instead of spot joining. Merely the joining portions between the upper back20and the upper back R/F30are indicated by white circles inFIG. 1, and illustrated inFIG. 2is a case where the upper back20and the upper back R/F30are joined to each other by caulking joining. The upper back20and each of the upper back R/F30, the side member S/A40, and the room partition panel are joined to each other in a plurality of places.

As illustrated inFIG. 1, the reinforcement outside portion35of the upper back R/F30is joined to the side member S/A40by spot welding. The spot welding is used because spot welding is possible as the upper back R/F30and the side member S/A40are made of the same iron (as the upper back R/F30and the side member S/A40are made of the same type of material). InFIG. 1, the joining portions between the reinforcement outside portion35and the side member S/A40are indicated by black circles.

As illustrated inFIG. 2, of the joining portions between the upper back20and the upper back R/F30, the side member S/A40, and the room partition panel, joining portions D between the upper back20and the front flange31of the upper back R/F30, the side member S/A40, and the room partition panel are covered with the interior material110and are places that a user cannot see. In contrast, rear side joining portions B, which are the joining portions between the upper back20and the rear flange32of the upper back R/F30, are places that a user can see as the upper surface of the rear flange32is the front rain gutter portion32athat can be seen when a user opens the luggage door70. Accordingly, in order to improve the design of the vehicle rear portion structure10, it is desirable that the rear side joining portion B is hidden when a user opens the luggage door70. In the example of the disclosure, the rear side joining portion B is covered from above by the luggage weather rubber50provided at the opening edge of the luggage room60.

The luggage weather rubber50is made of an elastically deformable soft resin. When the luggage door70is open, the luggage weather rubber50is not pushed by the luggage door70and undergoes no elastic deformation. When the luggage door70is closed, in contrast, the luggage weather rubber50is pushed by a seal surface71aof a door inner71of the luggage door70and is elastically deformed.

As illustrated inFIG. 1, the luggage weather rubber50is provided continuously over the entire circumference of the opening of the luggage room60. The luggage weather rubber50is attached to the luggage opening flange34of the upper back R/F30at the front side part thereof, attached to the trough42of the side member S/A40at each of both right and left side parts thereof, and attached to the lower back90at the rear side part thereof. As illustrated inFIG. 2, the luggage weather rubber50has an attachment portion51attached to the luggage opening flange34of the upper back R/F30, the trough42, and the lower back90and a lip52extending from the attachment portion51in a direction to enlarge the opening of the luggage room60(outer peripheral side).

In the cross-sectional view of the luggage weather rubber50(sectional view orthogonal to the longitudinal direction), the shape of the luggage weather rubber50is constant (including almost constant) over the entire circumference of the luggage weather rubber50and a length L of the lip52from the attachment portion51is constant (including almost constant) over the entire circumference of the luggage weather rubber50. The length L of the lip52from the attachment portion51is equal to or greater than the length at which the lip52reaches a vehicle front side end B0of the rear side joining portion B and is equal to or less than the length at which the lip52reaches the rear wall33cof the bulging portion33in the vehicle width direction center portion of the opening edge61on the front side of the luggage room60. As illustrated inFIG. 1, the rear side joining portions B provided in a plurality of places in the vehicle width direction are covered with the lip52of the luggage weather rubber50.

How to determine the vehicle width direction position of the vehicle width direction end24of the upper back20will be described below.

In order to further improve the rigidity of the vehicle rear portion structure10by providing the upper back R/F30, it is desirable that the rear side joining portion B is provided at a position close to a ridge line33eon the rear side of the bulging portion33. At least a corner portion61aof the opening edge61on the front side of the luggage room60is curved rearward. Accordingly, in the corner portion61aor the vicinity of the corner portion where the opening edge61on the front side of the luggage room60leaves the ridge line33erearward, a position is generated where it is impossible to cover and hide the rear side joining portion B with the lip52having the length L. The parting position (vehicle width direction end24) of the upper back20is set between an outermost side joining portion B1and an adjacent spot joining portion C1. Of the rear side joining portions B provided in a plurality of places in the vehicle width direction, the outermost side joining portion B1is on the outermost side in the vehicle width direction that can be covered and hidden with the lip52having the length L. Of spot joining portions C between the reinforcement outside portion35and the side member S/A40, the adjacent spot joining portion C1is provided at a position that is not covered (cannot be covered) with the luggage weather rubber50at a position adjacent to the outermost side joining portion B1.

The operation and effect of the example of the disclosure will be described below.

(A) Since the upper back20is joined to the rear flange32as well as the front flange31of the upper back R/F30, the upper back20is provided to extend rearward up to the opening of the luggage room60(including the vicinity of the opening of the luggage room). As a result, the weight reduction rate in a case where the upper back20is made of a material lighter than the material of the upper back R/F30can be maximized rearward unlike in a case where the upper back20is joined to the front flange31of the upper back R/F30without being joined to the rear flange32.

(B) Since the rear side joining portion B, which is the joining portion between the upper back20and the rear flange32of the upper back R/F30, is covered with the luggage weather rubber50, the rear side joining portion B being seen when the luggage door70is open can be suppressed. Accordingly, even in a case where the upper back20is provided to extend rearward up to the opening of the luggage room60, the design at a time when the luggage door70is open can be further improved.

(C) Since the rear side joining portion B is covered with the luggage weather rubber50, a new part such as a garnish merely for covering and hiding the rear side joining portion B is unnecessary. Accordingly, unlike in a case where a new part is added, an increase in the number of parts can be further suppressed, which is advantageous in terms of cost.

(D) Since the rear side joining portion B is covered with the lip52of the luggage weather rubber50, it is possible to cover the rear side joining portion B with a simple configuration as compared with a case where the rear side joining portion B is covered with the attachment portion51of the luggage weather rubber50.

(E) Since the length L of the lip52from the attachment portion51in the cross-sectional view of the luggage weather rubber50is constant over the entire circumference of the luggage weather rubber50, the luggage weather rubber50can be inexpensively manufactured as compared with a case where the length of the lip52is different.

(F) It is desirable that the opening of the luggage room60is large in view of improving the usability of the luggage room60. Accordingly, it is desirable that the length of the rear flange32of the upper back R/F30in the front-rear direction is short, and the length is minimized in the vehicle width direction center portion of the opening edge61on the front side of the luggage room60. In the example of the disclosure, the length of the lip52from the attachment portion51is set based on the vehicle width direction center portion of the opening edge61on the front side of the luggage room60, that is, the part where the length of the rear flange32of the upper back R/F30in the front-rear direction is minimized and is equal to or greater than the length at which the lip52reaches the vehicle front side end B0of the rear side joining portion B and equal to or less than the length at which the lip52reaches the bulging portion33. Accordingly, across the entire vehicle width direction area of the upper back R/F30, (i) it is possible to further suppress the lip52abutting against the bulging portion33of the upper back R/F30to be bent and cause a poor appearance and (ii) it is possible to further suppress the necessity of displacing the opening edge61on the front side of the luggage room60to the rear side of the vehicle in order to ensure a disposition space for the lip52.

(G) Since the upper back R/F30is joined by spot welding to the vehicle body member (side member S/A40) made of the same type of material as the upper back R/F30in the reinforcement outside portion35, the joining place is not conspicuous and the design can be further improved unlike in a case where joining is performed by caulking joining, bolt joining, or rivet joining, which are joining methods for dissimilar materials.

(H) The vehicle width direction end24of the upper back20is between the outermost side joining portion B1, which is on the outermost side in the vehicle width direction among the plurality of rear side joining portions B, and the adjacent spot joining portion C1, which is provided at a position that is not covered with the luggage weather rubber50at a position adjacent to the outermost side joining portion B1among the spot joining portions C between the reinforcement outside portion35and the side member S/A40. Accordingly, the vehicle width direction end24of the upper back20can be set at the outermost side position where the rear side joining portion B can be covered with the luggage weather rubber50. Accordingly, in a case where the rear side joining portion B is covered with the luggage weather rubber50, the weight reduction rate in a case where the upper back20is made of a material lighter than the material of the upper back R/F30can be maximized in the vehicle width direction.

Although an embodiment has been described in detail above, the disclosure is not limited to the above-described embodiment, and various modifications or changes may be made within the scope of the gist of the present disclosure.