A sealing assembly

Abstract: The invention relates to a sealing assembly for sealing two surfaces (PA,38C;PA,58C) of two elements (P,38;P,58) by means of a seal member (40;60) arranged between the two surfaces, wherein the two elements (P,38;P,58) are pressed against each other by means of coupling means (15) acting between them and applying a bending moment to at least one (38;58) of the two elements (P,38;P,58) such that the corresponding surface(s) is/are deformed. In alternative aspect of the invention, the seal element (40) is shaped such that it compensates the deformation of the surface(s). In another alternative aspect of the invention, at least one (58) of the two elements is shaped such that the sealing force is made uniform. Thus, a reduction in a water entry preventing function of the sealing assembly resulting from the deflection of the housing caused by the engagement resistance is prevented.

Description: DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a waterproof connector for connecting a pair of housings by means of coupling members such as a bolt and a nut. One example of the known waterproof connectors is shown in FIG. 8. The waterproof connector 1 is assembled as follows. A male housing 4 mounting unillustrated male terminal fittings is fixed in a mount hole 3 of a panel 2 by means of an unillustrated mounting means such that an opening of a hood (receptacle) 5 of the male housing 4 is in conformity with the mount hole 3. On the other hand, a female housing 6 mounting unillustrated female terminal fittings is slightly inserted into the receptacle 5 through the mount hole 3 from the side of the panel 2 opposite from the male housing 4. At this stage, if one bolt 7 mounted on the female housing 6 is spirally engaged with an unillustrated nut mounted on the male housing 4, the female housing 6 moves closer to the male housing 4, with the result that the male and female terminal fittings are engaged. In this waterproof connector 1, a seal member 8 is mounted on the female housing 6 in order to prevent entry of water from the female housing 6 to the male housing 4 through the mount hole 3 of the panel 2. When the male and female housings 4 and 6 are brought into a specified assembled state, the seal member 8 comes into close contact with the surface of the panel 2 while undergoing an elastic deformation. As a result, water entering between the female housing 6 and the mount hole 3 is generally prevented from further entering the male housing 4. In the above waterproof connector 1, when the housings 4 and 6 come closer to each other by fastening the bolt 7 with the nut, an engagement resisting force counteracts an approach of the radially inner portions of the housings 4 and 6 beyond the fixed distance between radially outer portions of the male and the female housings 4 and 6, provided by the panel 2 and the seal member 8. Accordingly, a portion of the female housing 6 in the vicinity of the bolt 7 is forcibly moved toward the male housing 4 by fastening of the bolt 7. On the other hand, a bending moment larger than a rigidity of the female housing 6 acts on portions of the female housing 6 distant from the bolt 7 due to the engagement resisting force, thereby elastically deflecting these portions. Therefore, the female housing 6 is brought into such a curved state where it is more spaced apart from the panel 2 as it extends more distant from the bolt 7. In such a state, a sealing force acting between the seal member 8 and the panel 2 becomes weaker as the seal member 8 extends more distant from the bolt 7. As a result, a water entry preventing function of the seal member 8 becomes nonuniform, thereby making water more likely to leak into the housings. A method as disclosed in Japanese Unexamined Utility Model Publication No. 4-69874 may be adopted to solve the above problem. Specifically, four bolts are mounted at respective corners of a terminal fitting mounting area. The respective bolts are turned together by a gear mechanism so that the entire housing is forcibly and uniformly moved closer to the mating housing. However, according to this method, the use of an increased number of bolts and the gear mechanism leads not only to a larger size housing, but also to an increased production cost resulting from the more complicated construction. This problem is found not only in waterproof connectors of the panel mount type, but also in waterproof connectors in which a seal member is directly mounted between a male housing and a female housing. The invention was developed in view of the above problem, and an object thereof is to prevent a reduction in a water entry preventing function resulting from a deflection of a housing without using a large size mechanism and making the housing larger. The above object is accomplished by the invention defined in claims 1 and 2. According to the invention, when the two elements are moved closer to each other by the coupling means, at least one element (on its corresponding surface) is deformed in such a curved manner that it is more distant from the mating element as it extends more distant from the coupling means. The deformation of the at least one element causes the seal member to be deformed and curved in the same direction. However, either the seal member or the deformed element(s) (or both) is/are shaped such that the seal element is entirely and uniformly brought into contact with the surfaces to be sealed. In other words, the sealing force is made uniform over the sealing area. Preferably, the curve of the seal member caused by the deformation is reverse of the curve of the seal member. Accordingly, the sealing surface of the seal member undergoes a change of state: from a curved state where it is closer to the sealed surface as it extends more distant from the coupling means, to a state where it can entirely and uniformly be brought into close contact with the surfaces to be sealed. Therefore, a water entry preventing effect can be satisfactorily realized between the seal member and the entire surfaces to be sealed. Further, according to the invention, it is not necessary to provide means for restricting the bending (and deformation) of the element(s) which means makes the housing larger and leads to an increased production cost resulting from the use of a complicated mechanism. Preferably, the curved shape of the sealing surface of the seal member is formed by making the seal member thicker as it extends more distant from the coupling means. Alternatively, the curved shape of the sealing surface is formed by making the thickness of the seal member constant and by preforming the element(s) such that its(their) surface(s) provide(s) for a uniform sealing force after being deformed. These and other objects, features and advantages of the present invention will become more apparent upon a reading of the following detailed description and accompanying drawings in which: FIG. 1 is a section of a first embodiment according to the invention in its assembled state, Fig. 2 is a side view of the first embodiment in its assembled state, Fig. 3 is a side view of a female housing of the first embodiment before it is assembled, Fig. 4 is a section showing the shape of a seal portion of a grommet of the first embodiment, Fig. 5 is a section along A-A of Fig. 4, Fig. 6 is a side view of a second embodiment in its assembled state, Fig. 7 is a side view of a female housing of the second embodiment before it is assembled, and Fig. 8 is a side view of a prior art waterproof connector. Hereafter, a first embodiment according to the invention is described with respect to FIGS. 1 to 5. A waterproof connector 10 according to this embodiment is mounted on a panel P, and includes a male housing 20 mounted in advance on the panel P and a female housing 30 to be assembled with the already mounted male housing 20. The male housing 20 is of a synthetic resin, and has a vertically relatively long rectangular front surface. A receptacle 21 projects along a periphery of the front surface of the male housing 20. Inside the male housing 20, a plurality of cavities 22 for accommodating unillustrated male terminal fittings extend from a front end surface of the receptacle 21 to a rear end surface of the male housing 20. The plurality of cavities 22 are arranged one over another in the vertical direction except for a portion of the male housing 20 located slightly lower than a vertical center of the male housing. A projection 23 projecting forward from the front end surface of the receptacle 21 where no cavities 22 are formed is formed with a through hole 24 extending in a direction in which the housings 20 and 30 are engaged (i.e., a lateral direction in FIG. 1). In the through hole 24, a nut 25 mounted from a lateral side of the male housing 20 is fixed such that it neither moves in a longitudinal axis direction nor rotates about a longitudinal axis. The male housing 20 is secured on the right surface of the panel P in FIG. 1 by engaging projections 26 formed at upper and lower edges of an opening of the receptacle 21 with a mount hole H of the panel P. On the other hand, the female housing 30 is of a synthetic resin, and has such a vertically relatively long rectangular cross-section that it can be fitted into the receptacle 21. In the female housing 30, a plurality of cavities 32 for accommodating unillustrated female terminal fittings extend from a front end surface of the female housing 30 to a rear end surface thereof. The plurality of cavities 32 are arranged one over another in the vertical direction except for a portion of the male housing 30 located slightly lower than a vertical center of the male housing. A recess 33 engageable with the projection 23 of the male housing 20 is formed on the front end surface of the female housing 30 where no cavities 32 are formed. In the bottom surface of the recess 33, a bolt hole 34, which is a through hole extending to the rear end surface of the female housing 30, is coaxially formed with the nut 25. A bolt 35 which forms a coupling member 15 together with the nut 25 is inserted into the bolt hole 34. An external thread portion 35B spirally engageable with the nut 25 is formed at the leading end of a shaft 35A of the bolt 35. In a position of the shaft 35A contiguous with a head 35C, there is formed a pressing portion 35D engageable with a rear opening edge of the bolt hole 34. The pressing portion 35D has a larger diameter than the shaft 35A, thereby forming a stepped portion at the boundary between the pressing portion 35D and the shaft 35A. Further, the head 35C is formed with a jaw portion 35E engageable from behind with a grommet cover 38 to be described later. A grommet holder 36 having openings 36A and opening 36B in conformity with the bolt hole 34 and a cylindrical portion 37B of a grommet 37, respectively, is mounted at a rear end of the female housing 30. The grommet 37 having an opening 37A in conformity with the bolt hole 34 is mounted on the outer surface of the grommet holder 36 such that it covers the entire rear end surface of the female housing 30. A bundle of unillustrated wires connected with the female terminal fittings extending backward of the female housing 30 from the cavities 32 are inserted into the cylindrical portion 37B formed in the grommet 37. The grommet cover 38 of metal having openings 38A and 38B in conformity with the bolt hole 34 and the cylindrical portion 37B of the grommet 37, respectively, are mounted at the outside of the grommet 37. The grommet 37 is of an elastically deformable rubber. The periphery of the grommet 37 acts as a seal portion 40 which is sealably in contact with the left (rear) surface PA of the panel P to be sealed in an assembled state of the housings 20 and 30. The seal portion 40 is adapted to prevent entry of water from the female housing 30 to the male housing 20 through a clearance between the mount hole H of the panel P and the female housing 30. As shown in FIGS. 2, 3 and 4, a lateral edge of the seal portion 40 extending in the vertical direction has a nonuniform thickness, which is a dimension in the engaging direction of the housings 20 and 30 (a lateral direction in FIGS. 3 and 4). Specifically, the thickness of the seal portion 40 is smallest at a height corresponding to the position of the bolt 35, and gradually increases as the seal portion extends more upward and downward from this height. The rear surface of the seal portion 40 having a variable thickness and coming into contact with the grommet cover 38 is flat (a left surface in FIGS. 3 and 4), so that it is in parallel with a sealed surface PA of the panel P when the female housing 30 is positioned in a posture to be assembled with the male housing 20 (see FIG. 3, where the panel P is shown twice in order to demonstrate parallelism). Therefore, a sealing surface of the seal portion 40 (a right surface in FIGS. 3 and 4) facing the sealed surface PA forms a concave surface with respect to the sealed surface PA such that it is closer to the sealed surface PA as it extends more toward its upper and lower ends, i.e., as it extends more distant from the bolt 35. The horizontal upper and lower edges of the seal portion 40 have a uniform thickness as shown in FIG. 5 as they are closer to the bolt 35 than the upper and lower ends. Next, the operation of this embodiment is described. When the assembly of the female housing 30, grommet holder 36, grommet 37 and grommet cover 38 is assembled with the male housing 20 which is securely mounted on the panel P in advance, the external thread portion 35B of the bolt 35 is spirally engaged with the nut 25 after the female housing 30 is inserted into the receptacle 21 by a certain distance. As the bolt 35 is fastened, the pressing portion 35D of the bolt 35 comes into engagement with the opening edge of the bolt hole 34 to pressingly move the female housing 30 toward the male housing 20, and the jaw portion 35E of the head 35C of the bolt 35 comes into engagement with the grommet cover 38 to pressingly move the grommet cover 38, the grommet 37 and the grommet holder 36 toward the male housing 20. When the male and female housings 20 and 30 are brought into a proper final assembled state where the male and female terminal fittings are properly engaged, the fastening of the bolt 35 is stopped, thereby completing the assembling operation. In the above operation, the male and female terminal fittings are engaged as the male and female housings 20 and 30 are assembled. At this stage, there is produced an engagement resisting force which prevents an approach of the radially outer portions of the housings 20 and 30 and, hence, counteracts an approach of the radially inner portions (portions close to the bolt 35) of the housings 20 and 30. This engagement resisting force acts on the housings 20 and 30. However, since the male housing 20 is secured on the panel P, only the female housing 30 is subjected to the engagement resisting force. However, the portion of the female housing 30 close to the bolt 35 is forcibly moved toward the male housing 20 since a fastening force of the bolt 35 directly acts thereon. On the other hand, though not directly subjected to the fastening force of the bolt 35, the portions of the female housing 30 above and below the bolt 35 are also moved toward the male housing 20 due to rigidity of the female housing 30, the grommet holder 36 and the grommet cover 38 (however, not by the same extent as close to the bolt 35). Hence, a larger bending moment due to the engagement resisting force acts in positions of the female housing 30 more distant from the bolt 35, i.e., in positions closer to the upper and lower edges of the female housing 30, thereby curving the female housing 30 away from the male housing 20. If the female housing 30 (and the grommet cover 38) is deformed such that the upper and lower edges thereof become more distant from the panel P, the seal portion 40 is deformed and curved in a similar direction. However, the seal portion 40 is formed reversely of the curve of the sealing surface 40A. Accordingly, the sealing surface 40A undergoes a change of state: from a curved state where it is closer to the sealed surface PA of the panel P as it extends more toward its upper and lower edges away from the bolt 35, to a flat state where it is flat and parallel with the sealed surface PA. The sealing surface 40A comes into close contact with the panel P while undergoing an elastic deformation (see FIG. 2). Thus, the seal portion 40 is uniformly and strongly in close contact with the sealed surface PA over its entire sealing surface 40A, with the result that entry of water from the female housing 30 to the male housing 20 through a clearance between the mount hole H of the panel P and the female housing 30 can be prevented. As is clear from the above description, according to this embodiment, the sealing surface 40A of the seal portion 40 has a curved shape, taking into consideration that the female housing 30 is caused to curve due to the engagement resistance between the male and female terminal fittings. Accordingly, the seal portion 40 exhibits a high water entry preventing function in the assembled state of the housings 20 and 30. Further, according to this embodiment, it is not necessary to provide means for preventing a deformation of the female housing 30 caused by the engagement resistance between the male and female terminal fittings. Thus, unlike the waterproof connector provided with the deformation preventing means, the connector according to the embodiment does not meet problems of a larger size and an increased production cost resulting from the sue of a complicated mechanism. Next, a second embodiment according to the invention is described with reference to FIGS. 6 and 7. A waterproof connector of the second embodiment differs from that of the first embodiment in the shape of the female housing and the seal portion. Since the other construction is same as in the first embodiment, no description is given thereto with regards the structure, the operation and the effect thereof by identifying like elements by like reference numerals. In a female housing 50 according to the second embodiment, a thickness of a seal portion 60 in a direction in which housings 20 and 50 are engaged (a lateral direction in FIGS. 6 and 7) is uniform along the vertical direction. The surface of a grommet cover 58 in contact with the seal portion 60 has such a curved shape that it is closer to the panel P as it extends more toward its upper and lower edges from the height of the bolt 35, i.e., away from the bolt 35. Accordingly, similar to the first embodiment, a sealing surface 60A of the seal portion 60 (a right surface in FIGS. 6 and 7) facing a sealed surface PA has such a curved shape that it is closer to the sealed surface PA as it extends more distant from the bolt 35. When the female housing 50 is assembled with the male housing 20 secured on the panel P, the female housing 50 and the seal portion 60 are deflected in such a curved manner that the upper and lower edges thereof becomes more distant from the panel P. Then, the sealing surface 60A undergoes a change of state: from a curved state where it is closer to the sealed surface PA of the panel P as it extends more toward its upper and lower edges away from the bolt 35, to a flat state where it is flat and parallel with the sealed surface PA. In this state, the sealing surface 60A comes into close contact with the panel P while undergoing an elastic deformation (see FIG. 6). Thus, the sealing surface 60A is entirely, uniformly and strongly in close contact with the sealed surface PA, with the result that entry of water from the female housing 50 to the male housing 20 through a clearance between a mount hole H of the panel P and the female housing 30 can be prevented. As is clear from the above description, according to this embodiment, the sealing surface 60A has a curved shape, taking into consideration that the female housing 50 is caused to curve due to the engagement resistance between male and female terminal fittings. Accordingly, the seal portion 60 exhibits a high water entry preventing function in the assembled state of the housings 20 and 50. The present invention is not limited to the above described and illustrated embodiments. The invention may be embodied in a variety of other forms. (1) Since the housing has a vertically long shape when viewed from front and the terminal fittings are arranged one over another in the vertical direction in the foregoing embodiments, the sealing surface of the seal portion is curved only in the vertical direction. However, in the case where the housing has, for example, a square-like shape when viewed from front and the terminal fittings are arranged in the lateral direction as well as in the vertical direction, the sealing surface may be curved not only in the vertical direction, but also in the lateral direction. Then, a water entry preventing force of the seal portion can be uniform over the entire sealing surface. (2) Although the foregoing embodiments are described with respect to the case where only one bolt is provided to form the coupling member, the invention may be applied to a case where two or more bolts are used. (3) Although the foregoing embodiments are described with respect to the case where the invention is applied to waterproof connectors of the panel mount type, the invention may be applied to water connectors of the type in which no panel is mounted and entry of water is prevented by a seal portion mounted between male and female housings which are directly brought into contact with each other.

Claims: A sealing assembly comprising two elements (P,38) and a seal member (40) arranged between two surfaces (PA,38C) of the two elements for sealing them, wherein the two elements (P,38) are pressed against each other by means of coupling means (15) acting between them and applying a bending moment to at least one (38) of the two elements (P,38) such that the corresponding surface(s) (38C) is/are deformed, characterised in that the seal member (40) is shaped such that it compensates the deformation of the surface(s) (38C). A sealing assembly comprising two elements (P,58) and a seal member (60) arranged between two surfaces (PA,58C) of the two elements for sealing them, wherein the two elements (P,58) are pressed against each other by means of coupling means (15) acting between them and applying a bending moment to at least one (58) of the two elements such that the corresponding surface(s) (58C) is/are deformed, characterised in that at least one (58) of the two elements is shaped such that the sealing force is made uniform. A sealing assembly according to claim 1 or 2, wherein the elements (P,38; P,58) are parts of a waterproof connector (10) having a male portion (20,P) and a female portion (30,36,37,38; 50,58) to be sealingly coupled with each other. A sealing assembly according to claim 3, wherein the seal member (40;60) is arranged between a plate (P) of the male portion (20,P) and a seal cover element (38;58) of the female portion (30,36,37,38; 50,58). A sealing assembly according to claim 3 or 4, wherein the seal member (40;60) is provided on one of the male and female portions. A sealing assembly according to claim 1, wherein the seal member (40) is shaped such that its thickness increases with the distance from the coupling means (15) in at least one direction. A sealing assembly according to claim 2, wherein the seal member (60) is shaped such that its thickness is constant. A sealing assembly according to any of claims 3 to 5, wherein the male and female portions are coupled by means of a screw/nut assembly (35,25) provided at the male and female portion, respectively. A sealing assembly according to any of claims 1 to 8, wherein the coupling means (15) is located approximately centrally of the surfaces (PA,38C;PA,58C) to be sealed.

Inventors: SAKATANI ATSUSHI, SAKURAI TOSHIKAZU, SAKATANI, ATSUSHI, SAKURAI, TOSHIKAZU, Sakatani, Atsushi, c/o Sumitomo Wiring Systems,, Sakurai, Toshikazu, c/o Sumitomo Wiring Systems,
Applicants: SUMITOMO WIRING SYSTEMS, SUMITOMO WIRING SYSTEMS, LTD.
Application year: 1995
Main classification: H01R13
IPC codes: H01R13