JPS5917487B2 - moisture seal grommet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a moisture-sealing grommet for combination with an electrical connector.

BACKGROUND OF THE INVENTION This invention relates specifically to moisture-sealing grommets disposed at the rear of electrical connectors to prevent moisture from entering the connector.

Electrical connectors generally include a cylindrical housing, an insulating insert mounted within the housing, a plurality of electrical contacts spaced within the insulating insert, and a wire connected to each electrical contact. and a grommet for accommodating the electrical connector and providing a seal at the rear of the electrical connector to prevent moisture from entering the electrical connector and adversely affecting the electrical connector.

A better moisture seal between the grommet and the drop-in wire can extend the life of the electrical connector and stabilize its operation. The close contact density in today's electrical connectors allows for maximum grommet sealing.
0 has arisen.

For example, the greater the pressure exerted by the grommet on the drop wire, the better the sealing properties. However, in general, increasing the sealing pressure on the grommet results in distortion of the grommet.
This results in poor contact between the grommet and the drop wire. Another problem with moisture sealing between the grommet and the drop wire is that the shape of the passageway that houses the drop wire creates stresses within the grommet so that when the wire is pulled through the grommet 30, the grommet may tear between adjacent passages, reducing or nullifying the sealing effect between adjacent passages and the wire. One attempt to minimize the above problems is to include a grommet that includes at least 352 constrictions within the wire receiving passageway that press against the wire to form a pressure-tight moisture seal. . To minimize stress, the constrictions in the shaped grommets are configured to be substantially not laterally aligned with the constrictions of adjacent passageways. A slight drawback to this shape of grommet is that the grommet is generally molded from rubber, so the above configuration has a 0.762 m7
! It is not possible to use core pins smaller than L (0.03 inches). The 0.762 mm core pin creates a constriction within the passageway that exerts pressure against the wire within the passageway to provide a pressure-tight moisture seal.

However, if a 0.02 inch core pin could be used, the constriction in the passageway would be smaller and more pressure would be applied to the wire to create a 0.02 inch diameter core pin in the grommet passageway. .762 will increase the sealing properties for small diameter wires having a diameter only slightly larger than the constriction of the dragon. In order to eliminate the above-mentioned disadvantages, the present invention consists of a body having a front surface, a rear surface and a plurality of parallel wire-receiving passages extending from the front surface to the rear surface, each said passage having a cylindrical portion and a cylindrical portion towards said rear surface. a plurality of wire sealing devices comprising an outwardly divergent curved section, the curved section having a minimum diameter smaller than the diameter of the cylindrical section; a maximum diameter at the rear surface that is greater than a diameter of the curved portion, and a minimum diameter of the curved portion is a first distance from the cylindrical portion and a maximum diameter of the curved portion is a first distance from the cylindrical portion. 2, and the ratio of the second distance to the first distance is greater than 1.5.

An embodiment of the present invention will be described in detail with reference to the accompanying drawings.

In the drawings, FIG. 1 shows a grommet 10 used within an electrical connector assembly to form a moisture seal between wires extending into a connector housing (not shown).

Grommet 10 includes a plurality of closely spaced passageways, each passageway receiving a wire (not shown) extending into the connector assembly and connected to an electrical contact. Grommet 10 is generally cylindrical and is made of an electrically insulating rubber or rubber-like material of medium hardness. A grommet 10 disposed at one end of the connector assembly (not shown) makes pressure-tight contact with the connector housing to prevent moisture from entering the connector and is typically coupled to an insulating insert that retains the electrical contacts. It has a curved surface 11 (FIG. 2). 2 is a schematic cross-sectional view of the grommet shown in FIG. 1; FIG. The grommet 10 has a front side 11 and a rear side 12.
and a plurality of spaced apart axially aligned passageways extending through the grommet from the front surface 11 to the rear surface 12. Each passageway includes a cylindrical portion 20 and a curved portion 30 that diverges outwardly toward the rear surface 12 from a constriction continuous with the cylindrical portion of the passageway. Curved section 30 of the passage
[MaeWestCONtOut]
r) or called an oval shape. FIG. 3 is a schematic, enlarged cross-sectional view of one of the passages through grommet 10, highlighting the important shapes and features of the passage.

As shown in FIG. 3, the cylindrical portion 20 of the passageway includes a wall 21 and the curved portion 30 of the passageway includes a wall 31.
The curved portion 30 of the passage preferably has a constant radius of curvature R and diverges outwardly towards an opening D3 in the rear face 12 of the grommet opening 0. The base point of the radius R is the curved part 3 of the passage.
0 and the cylindrical portion 20 at a distance Y1 from the intersection. The curved design of the passageway allows stresses to be reduced or ignored when the grommet 10 is stressed by the lead wire. The best location for the narrowest constriction within the curved section 30 is at a distance Y1 from the cylindrical section;
This distance Y1 is shorter than the distance Y2, which is equal to the axial length of the curved section 30 of the passage. Distance Y2 relative to distance Y1
A preferred ratio of is greater than 1.5. FIG. 4 shows a grommet with wire 40;
0 passes through a passage within grommet 10.

FIG. 4 shows how the wall 31 of the curved section 30 of the passageway is in pressure sealing contact with the wire 40 to prevent moisture from penetrating into the cylindrical section 20 of the grommet 10. The diameter of the wire 40 is slightly wider than the constriction D2 of the curved portion 30 of the passageway so that the wall 31 of the curved portion, which elastically deflects when the wire is pulled through the passageway, is in pressure-sealing contact with the wire 40. to form a moisture seal. The advantages of the grommet according to the invention over conventional grommets are:
The special contour of the passage (curved section 30) allows the wire to pass through while maintaining a seal between the wire and the grommet even when the wire is pulled to one side or moved 360 times around the opening. It is to support. The curved curved portion 30 also guides a contact insertion and removal tool (not shown). The breakaway tool has a tendency to cut into the wall of a grommet that has only a cylindrical portion, especially when used with small diameter wires. The curved shape 30 of the passageway aids in aligning the contact removal tool so that the tool does not cut into the wall 31 of the curved portion 30 of the passageway. Although the invention has been described in detail with respect to preferred embodiments thereof, those skilled in the art will recognize that numerous changes may be made without departing from the scope of the invention.

For example, certain features of the invention may be used to advantage without being used in conjunction with other features. Therefore, the described materials used to illustrate the principles of the invention are not intended to limit the scope of the invention.

[Brief explanation of the drawing]

1 is an end view of a moisture-sealing grommet according to the present invention for use in combination with an electrical connector insulation insert; FIG.
The figures are a schematic cross-sectional view of the grommet shown in Figure 1; - Figure 3 is an enlarged cross-sectional view of the passage highlighting the characteristics of the passage passing through the grommet; and Figure 4 is a cross-sectional view of the grommet. Figure 3 is a partial cross-sectional view of the grommet showing the wire passing through the grommet.

Claims (1)

[Claims] 1 comprising a body having a front surface, a rear surface and a plurality of parallel wire receiving passages extending from the front surface to the rear surface;
A device for sealing a plurality of wires, wherein each said passageway includes a cylindrical portion and a curved portion extending outwardly toward said rear surface, wherein said curved portion 30 is shaped like said cylindrical portion. Minimum diameter D smaller than diameter D_1 of portion 20
_2 and a maximum diameter D_3 at the rear surface 12 that is greater than a diameter D_1 of the cylindrical portion, with the minimum diameter D_2 of the curved portion 30 being a first distance Y_1 from the cylindrical portion 20; The maximum diameter D_3 of the curved portion is a second distance Y_2 from the cylindrical portion 20.
, and the ratio of said second distance Y_2 to said first distance Y_1 is greater than 1.5.