1. Field of the Invention
The present invention relates to a watertight connector.
2. Description of the Related Art
A known watertight connector has a housing with opposite front and rear ends. A fittable portion is disposed at the front end of the housing and is dimensioned to fit in a receptacle of a mating connector. Terminal fittings are mounted in the fittable portion and a tubular seal is mounted on the outer peripheral surface of a fittable portion. The seal seals a clearance between the outer peripheral surface of the fittable portion and the inner peripheral surface of the receptacle.
A holder is provided at the rear end of the fittable portion of the housing and a lock is formed at the rear end of the seal to prevent the seal from coming off the fittable portion when the watertight connector is withdrawn from the receptacle. The lock engages the holder to prevent loose forward movements of the seal and separation of the seal from the fittable portion.
It generally is desirable to shorten the seal along forward and backward directions to reduce connection resistance with the receptacle and to prevent the seal from buckling. Thus, the seal is at a rear end of the fittable portion and is held resiliently in contact with a front area of the receptacle.
The mating connector often is on a fixed piece of equipment and the watertight connector may have to be fit into the receptacle by touch due to a narrow space near the receptacle. Thus, the opening to the receptacle may be slanted outwardly to guide the insertion of the fittable portion. However, the degree of resilient deformation of the seal with the slanted surface changes depending on the depth of engagement of the fittable portion, and sealing performance is unstable. Accordingly, the slanted leading end cannot be a sealing surface. A portion of the receptacle more backward than the slanted opening is set as a sealing surface for resilient contact with the seal, and a resilient contact of the seal with the receptacle is near the front-end of the fittable portion.
The rear end of the seal is held at the rear end of the fittable portion so as not to come off. Thus, the seal must be longer along forward and backward directions if an attempt is made to position the resilient contact of the seal at the front end of the fittable portion. However, frictional resistance pushes the resilient contact portion of a longer seal back during the fitting operation, and hence the longer seal may buckle.
The present invention was developed in view of the above problems and an object thereof is to prevent a sealing member from being buckled.
The invention relates to a watertight connector with a housing in which at least one terminal fitting is accommodated. The watertight connector has a fittable portion that can be fit in and withdrawn from a receptacle of a mating connector. A substantially tubular seal is mounted on the outer peripheral surface of the fittable portion and is formed on its outer peripheral surface with at least one resilient contact that is held resiliently in contact with the inner peripheral surface of the receptacle. One or more fastening means are provided at the rear end of the fittable portion and/or at the rear end of the seal for preventing the seal from moving forward and off the fittable portion. One or more loose-movement preventing means are provided on the fittable portion and on the seal for preventing loose backward movement of the resilient contact.
The fastening means preferably are provided at the rear end of the fittable portion and/or at the rear end of the seal.
The loose-movement preventing means preferably is at the fittable portion and at the seal and engage each other to prevent loose backward movement of the resilient contact.
Frictional resistance that acts during the fitting of the watertight connector into the receptacle may push the resilient contact back. However, the loose-movement preventing means prevents the resilient contact from moving loosely backward in response to forces exerted by the receptacle. Thus, the seal will not buckle even if the seal is long along forward and backward directions and the resilient contact is at the front-end of the seal.
The loose-movement preventing means preferably comprises steps on the outer peripheral surface of the fittable portion and on the inner peripheral surface of the seal. The steps prevent the loose movements of the resilient contact by bringing into contact surfaces of the steps aligned at an angle to a fitting direction of the fittable portion into the receptacle.
A backward-acting pushing force exerted by the receptacle on the resilient contact is received by the step of the fittable portion via the step of the seal. The surfaces of the steps intersect the fitting direction of the fittable portion into the receptacle. Thus, the fittable portion can receive the pushing force from the receptacle to prevent loose backward movements of the resilient contact.
The steps of the fittable portion and the seal prevent the loose movements of the resilient contact by bringing into contact surfaces that overhang or are undercut with respect to the fitting direction. Thus, an acute-angled corner of each step bites in or engages an angled corner of the mating step due to the inclination of the overhanging surface to prevent the loose movements of the resilient contact. Accordingly, disengagement of the steps and loose movements of the resilient contact can be avoided.
The step of the seal is at a position near the resilient contact with respect to forward and backward directions.
The backward pushing force of the receptacle on the resilient contact deforms the resilient contact inwardly and the restoring force of the resilient contact presses the step of the seal against the outer peripheral surface of the fittable portion. Accordingly, the step of the seal will not disengage outwardly from the step of the fittable portion and loose movements of the resilient contact are prevented.
An escaping groove is formed in an area of the inner surface of the fittable portion that faces the terminal insertion space in the housing. The escaping groove avoids interference with an improper insertion preventing projection on the outer surface of the terminal fitting when the terminal fitting is inserted in a proper orientation. An area of the outer surface of the fittable portion corresponding to the escaping groove preferably forms a rib shape, and the front end of the rib-shaped projection defines the step.
A nonuniform thickness of the wall of the fittable portion can be reduced by forming the rib shape on the outer surface of the fittable portion to align with the escaping groove. Thus, a variation in the degree of deformation caused by thermal shrinkage (i.e. xe2x80x9csink marksxe2x80x9d) during the resin molding of the housing can be suppressed to ensure dimensional stability. Further, the step of the fittable portion takes advantage of the rib-shaped projection corresponding to the escaping groove. Accordingly, the shape of the fittable portion can be simplified as compared to a case where the step is separate from the rib-shaped projection.
The fastening means may comprise a stopper fit to the housing for engaging the seal and preventing the seal from moving forward.
A single loose-movement preventing means may be provided on each of the fittable portion and the seal around substantially the entire periphery thereof.
Alternatively, a plurality of loose-movement preventing means may be spaced around the periphery of the fittable portion and/or the seal.
These and other objects, features and advantages of the present invention will become more apparent upon reading of the following detailed description of preferred embodiments and accompanying drawings. It should be understood that even though embodiments are separately described, single features thereof may be combined to additional embodiments.