The present invention relates to an air conditioning duct to be positioned at a rear wall side of a vehicular instrument panel and a method for mounting the same.
In general vehicles including motor vehicles, there are many instances where the vehicles are mounted with air conditioning units with a view to provide a comfortable surrounding for passengers. A vehicular air conditioning system includes an air conditioning duct positioned at a rear side of an instrument panel mounted in a front part of a passenger compartment to allow cold air or hot air to be blown out into the passenger compartment through the duct. Such a duct is disclosed in, for example, Japanese Patent Laid-Open Publication No. HEI-11-321287.
The duct disclosed in Japanese Patent Laid-Open Publication No. HEI-11-321287 comprises a plurality of duct sections, interconnecting segments for interconnecting these duct sections and a leg portion protruding from one of the ducts, with the leg portion and the one of the duct sections being unitarily formed by a blow forming technology to form the air conditioning duct. Securing the aforementioned leg portion to the rear surface of the instrument panel 1 by vibration welding, hereinafter referred to as a vibrating deposition, allows the aforementioned air conditioning duct to be mounted to the instrument panel.
In order to improve the comfortable surrounding in the passenger compartment, it is desired for air conditioning to be efficiently carried out to preclude an uneven temperature distribution in the passenger compartment. To meet such a demand, it is a point that a plurality of air blowout openings must be located at respective suitable positions and the volumes of air discharged from the respective air blowout openings must be suitably distributed. In order to optimize the volumes of air to be distributed, it is thought that the air conditioning duct is formed with a plurality of partitions or with a plurality of air inlets. With such a structure, the air conditioning duct inevitably results in a complicated shape. When forming the air conditioning duct with such a complicated structure with the use of the abovementioned conventional technology, there is a limit in addressing issues of troublesome processing steps and complicated forming dies.
It is therefore an object of the present invention to provide a technology for enabling an air conditioning duct with a complicated structure, which is mounted to a vehicular instrument panel, to be manufactured in an easy manner.
According to a first aspect of the present invention, there is provided an air conditioning duct adapted to be located at a rear surface of a vehicular instrument panel, which comprises a first cylindrical duct, hereinafter referred to as a first cylindrical body; a second cylindrical duct, hereinafter referred to as a second cylindrical body, placed along the first cylindrical body; a plurality of fastener members, hereinafter referred to as fixture members, for joining the first and second cylindrical bodies to one another; and a leg portion extending from at least one of the first and second cylindrical bodies toward the vehicular instrument panel.
Thus, the present invention allows one piece of the air conditioning duct with a complicated structure to be manufactured with separate pieces of the cylindrical bodies. Joining these plural pieces of the cylindrical bodies with the plurality of the fixture members enables production of a single piece of the air conditioning duct. The unitarily formed air conditioning duct is mounted to the vehicular instrument panel via the leg portion extending toward the same. Thus, even when the air conditioning duct has the complicated structure, the presence of the plurality of the separate cylindrical bodies allows the individual cylindrical bodies to be formed in relatively simplified structures. This results in an easy production of the air conditioning duct.
Preferably, the fixture members are placed along the longitudinal direction of the first cylindrical body. Joining the first and second cylindrical bodies with the plurality of the fixture members allows the air conditioning duct to have an adequate entire shape and rigidity to provide a preferable result.
In a preferred form, at least one of the fixture members is located in the vicinity of the openings of the first and second cylindrical bodies. That is, the fixture member remains in the vicinity of the openings within worker""s reach, with a resultant improvement over the joining workability.
Desirably, the first and second cylindrical bodies include air blowout tubes, respectively, which extend toward the aforementioned vehicular instrument panel. Outlets of the air blowout tubes are formed in bell-mouthed shapes so as to mate with the air discharge pipes mounted at the aforementioned vehicular instrument panel. Thus, even when the outlets of the air blowout tubes are slightly dislocated with respect to the air bleed openings of the instrument panel, mating the outlets of the air blowout tubes with the air discharge pipes enables a matching of the outlets of the air blowout tubes with respect to the air discharge pipes in an easy manner.
The leg portion may be designed to be mounted to the vehicular instrument panel by the vibrating deposition and has a mount surface formed with a plurality of projections. Thus, the presence of the plurality of the projections allows a contact surface area per each projection to have a lower value than that of a single piece of projection as proposed in prior art practice. The presence of the individual projections with reduced contact surface areas decreases the heat value, which occurs during the vibrating deposition, by an amount equal to the reduced contact surface area. It is possible to further preclude a sink mark or irregular gloss caused on an external surface of the instrument panel due to heat generated during the vibrating deposition.
According to a second aspect of the present invention, there is provided a method for mounting an air conditioning duct, comprising the steps of: preparing a first cylindrical body and a second cylindrical body which are unitarily formed with leg portions, respectively; placing the first cylindrical body and the second cylindrical body along to one another and joining the first and second cylindrical bodies with a plurality of fixture members; and mounting the respective leg portions to the vehicular instrument panel by a vibrating deposition.
Thus, in accordance with the assembling method of the present invention, the second cylindrical body is placed along the first cylindrical body and both of these components are joined to one another with the plural pieces of the fixture members and, subsequently, the leg portion is mounted to the instrument panel by the vibrating deposition, resulting in an ease of fabrication of the air conditioning duct even with a complicated structure. In addition, since the unitarily formed air conditioning duct is mounted to the instrument panel with a work merely having the vibrating deposition, workability for mounting the air conditioning duct is highly improved.