JP2002184515A - Waterproof gasket for electric connection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gasket at reduced manufacturing and assembling cost, by reducing maintenance after use, keeping the waterproofing property for a long time. SOLUTION: A plural sheets of ring-shaped ribs 354a are formed at the inner peripheral surface of a cable hole 353 of an approximately cylinder-shaped waterproof gasket 35 in the direction of axis at approximately regular intervals, and at least one sheet of ring-shaped rib 352a is formed at the middle part in the axis direction of an outer peripheral surface 351.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a waterproof gasket used for a cable outlet in an electric connector for easily connecting and disconnecting an electric circuit at a connection portion of an electric wiring or an electric device of a railway vehicle or an industrial machine. .

[0002]

2. Description of the Related Art In electrical circuits of railway vehicles and other general industrial machines, electrical connectors (also referred to as couplers and connectors) are used for electrical wiring and electrical equipment which must be relatively frequently attached and detached. ing. In addition to single-core electrical connectors that connect a single electric wire, multi-core electrical connectors that connect multiple wires at the same time are available. An example of a conventional general electrical connector similar to that described in JP-39890 will be described with reference to the drawings.

FIG. 6 is a side view showing a partial cross section of a socket 1 of an electrical connector paired with a socket and a plug.
FIG. 7 is a front view of this as viewed from the left side of FIG. 6, and 11 is a substantially cylindrical casing made of metal,
Is a substantially cylindrical insulating base made of an insulating material such as a resin fitted therein, 13 is a socket contact of a conductor further mounted inside via an insulating base 12, and 13a is a rear part thereof (hereinafter referred to as the present specification). In the description, both the socket 1 and the plug 2 are referred to as the front side of the connection surface and the cable exit side is referred to as the rear side). A fastening gland for fixing the take-out portion of the cable 3 by screwing it to an end portion, 32 is a lock nut for fixing the same, 34 is a ring, 35 is a gasket, and 36 is a washer. 9 and 10 will be described later in detail with reference to FIGS.

FIG. 8 is a side view showing a partial cross section of the plug 2 in the electric connector. 6, 21 is a substantially cylindrical casing of the plug 2, 21a is a coupling part thereof, 22 is a substantially cylindrical insulating table fitted inside thereof, and 23 is an insulating base 22 via the insulating table 22. Further, a pin contact attached inside, a crimping portion 23a connecting the core wire of the cable behind the pin contact, 3 a cable connected to the pin contact 23, and 33 a cable holder to be described later.

A one-touch type ball lock type coupling has been described as a means for connecting the casings 11 and 21. The details thereof are described in the above-mentioned Japanese Utility Model Publication No. 57-39890, and will not be described here. . In addition, a bolt fastening method of providing a flange on a casing and connecting the flange with a bolt is also common. In the case of a three-core connector for three-phase AC or a multi-core connector for connecting a plurality of circuits simultaneously, a plurality of socket contacts are provided in the casing.
13 and the pin contacts 23 are arranged in parallel, and are insulated from each other and from the casing by an insulating base provided with a plurality of holes.

Incidentally, in such an electric connector, one problem is a measure for waterproofing the electric circuit portion against the surrounding environment. For example, in the case of an electrical connector for electrically connecting a vehicle to a vehicle, Japanese Industrial Standards state that JIS E
4202 "Jumper coupler", section 4.7, "Water must not be inundated when the test of 9.7 is performed." In the case where only the plug is inserted and the plug receiver is immersed in a position 1 m underwater up to the surface for 15 minutes, the presence or absence of water infiltration is checked. ""Connector" and "plug stopper" are defined as "socket contact" and "plug" as "pin contact"). It can be seen that the atmospheric pressure fluctuates as if it did not exist, and there is a trend to require a high degree of water resistance that cannot be covered by the above standard.

[0007] As a waterproof measure at the joint portion of the casing, it is usual to take measures such as improving the mechanical accuracy of the casing and inserting an O-ring into a stepped portion or the like according to the coupling structure. On the other hand, as a waterproof measure at the cable outlets of the socket contacts and the pin contacts, various packings are inserted between the casing and the cable to tighten them.

An example of a conventional waterproof structure in such a cable outlet will be described with reference to FIGS. FIG. 9 is a sectional view showing a cable outlet portion of the plug 2, and FIG. 10 is a partial side view showing the waterproof structure disassembled along the cable 3 connected to the pin contact 23 from the pin contact 23. It is. The waterproof structure of the socket 1 is exactly the same.

As shown in FIG. 9, a washer 36 is applied to a rear stepped portion of the casing 21, and a cylindrical waterproof gasket (also referred to as a grommet) 35 made of synthetic rubber is inserted behind the washer 36, and a ring 34 is inserted. This is screwed into the threaded portion at the rear end of the casing 21 with the tightening gland 31 covered, but the gasket 35 sandwiched between the washer 36 and the ring 34 is compressed in the longitudinal direction by adjusting the screwing, and the inner diameter side also has an outer diameter. It also bulges out to the side and closely adheres to the outer diameter of the cable 3 and also to the inner diameter of the casing 21 to form a waterproof structure. Here, the tightening gland 31 is not fully tightened to the rear end of the casing 21 and is positioned by the lock nut 32 or the like shown in FIG.
In general, the tightening gland 31 has been regularly tightened in response to the covering of the cable 3 or the deterioration of the gasket 35.

However, due to recent advances in insulating materials, cross-linked polyethylene and Freon Rex have been used in place of conventional rubbers in order to reduce the thickness of the cable coating to reduce the weight of the vehicle and to achieve flame retardancy. As a result, the elasticity (restorability) of the insulating coating becomes poor, and a vicious cycle occurs in which the tightening promotes the deformation that further reduces the outer diameter of the cable, and retightening with a gasket must be performed very frequently. There is a problem that it requires a lot of manpower.

The inner diameter of the gasket 35 is generally set to correspond to the maximum outer diameter of the insulating coating of the cable, but the tolerance of the outer diameter of the electric wire or the multi-core cable is large. In many cases, one type of gasket cannot be used, so that it is necessary to prepare a plurality of types of gaskets having different inner diameters. In addition, gaskets
Assuming that the inner diameter of 35 is a value corresponding to the outer diameter of the insulating coating of the cable, as shown in FIG. 35 cannot pass, so tighten the gland 31,
It is necessary to pass the gasket 35 etc. through the cable 3,
There were restrictions on work procedures. Further, when it is necessary to remove the gasket later to replace the gasket, the connection between the contact and the cable has to be cut.

On the other hand, as a measure for waterproofing between the outer diameter side of the gasket 35 and the casing, an O-ring is attached to the outer diameter portion of the gasket 35 in some cases. This is effective, but when installing the cable,
There is a problem that a new operation of attaching a ring is added. In order to solve these problems, the present applicant has aimed to improve the waterproof performance without adding an assembling operation by forming linear projections corresponding to O-rings on the inner diameter portion and the outer diameter portion. Proposed a waterproof gasket for an electrical connector, which has been disclosed in Japanese Patent Application Laid-Open No. H11-178165.

This will be described with reference to FIG. This figure is a side view partially showing a gasket showing an embodiment of the invention described in JP-A-11-178165, in which 35 is a gasket, 351 is an outer peripheral surface thereof, and 355 is a linear shape formed on the outer peripheral surface 351. Protrusions,
353 is a cable hole corresponding to the inner peripheral surface of the gasket 35, 35
Reference numeral 6 denotes a linear projection formed in the cable hole 353.
That is, this gasket 35 is similar to that described with reference to FIG. 6 to FIG. A substantially cylindrical waterproof gasket inserted into the middle of the rear end of the casing and inserted into a cable connected to the contact, wherein a plurality of circumferential gaskets are provided on the inner peripheral surface of the cable hole 353. It is characterized in that linear projections 356 are formed at substantially equal intervals, and at least one circumferential linear projection 355 is formed in the middle of the outer peripheral surface 351 in the longitudinal direction.

The linear projection 355 on the outer peripheral surface is obtained by integrating the O-ring previously mounted on the gasket with the gasket, and has a height of about 1 mm. Although the linear projection 356 of the cable hole is not particularly shown in the dimensions, it is elastically fitted to the cable outer diameter, and therefore has substantially the same size and shape. However, although the gasket described in Japanese Patent Application Laid-Open No. H11-178165 shows excellent waterproof performance at the beginning of use, the waterproofing effect is due to the compression deformation of the linear projections 355, 356, and the hardening and permanent deformation of the rubber occur over time. It became clear that the waterproof performance was reduced. In particular, the performance of the linear projection 356 on the cable hole side is significantly deteriorated as compared with the linear projection 355 on the outer peripheral surface which is compressed by the metal casing since the compression target is the same elastic body as the coating of the cable. .

[0015]

SUMMARY OF THE INVENTION The present invention solves these problems, reduces the manufacturing and assembly costs by changing the shape of the projections, maintains the waterproof performance for a long time, and performs maintenance after starting use. It is an object of the present invention to realize a gasket capable of reducing the number of gaskets.

[0016]

SUMMARY OF THE INVENTION The present invention is directed to a clamping gland screwed into a rear end of a casing and a rear end of the casing in an electric connector comprising a socket and a plug provided with contacts in a casing via an insulating base. And a substantially cylindrical waterproof gasket inserted in the middle of the cable and inserted into the cable connected to the contact, wherein a plurality of annular ribs are formed at substantially equal intervals in the axial direction on the inner peripheral surface of the cable hole. And / or a waterproof gasket for an electrical connector, wherein at least one annular rib is formed at an axially intermediate portion of an outer peripheral surface of the annular rib. The gasket for waterproofing in the above-mentioned electrical connector, wherein the ratio of h / t is 1.5 or more and 6.0 or less when h.

[0017]

According to the present invention, an annular rib that can be bent in the axial direction is formed on the outer peripheral surface of the gasket or on the inner peripheral cable hole instead of the linear projection. Since the bent surface of the cable does not come into contact with the outer casing or the covering of the cable to achieve waterproofing, the waterproofing performance can be maintained for a long time without causing deformation or hardening of the covering of the annular rib or the cable.

[0018]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. [Embodiment 1] FIG. 1 is a side view showing a gasket according to a first embodiment of the present invention in a partial cross section. As in the above description, 35 is a gasket, 351 is its outer peripheral surface, and 352a is its outer peripheral surface. 353 is a cable hole, and 354a is a plurality of annular ribs formed on the inner peripheral surface at substantially equal intervals in the axial direction.

That is, the gasket 35 is for a single-core connector, and has a cylindrical main body and annular ribs on the inner and outer peripheral surfaces integrally formed of an elastic material such as silicon rubber. The overall shape is substantially cylindrical, similar to the conventional one, but a single circumferential annular rib 352a is formed near the longitudinal center of the outer peripheral surface, and the inner peripheral surface of the cable hole 353 is also formed. A plurality of circumferential annular ribs 354a are formed.

In this embodiment, the annular rib 352a on the outer peripheral surface and the annular rib 354a on the inner peripheral surface have substantially the same cross-sectional shape. As an example, an enlarged partial cross-sectional view of the annular rib 354a on the inner peripheral surface is shown in FIG. (A) is a natural state in which no deformation is applied. If the thickness is t and the protrusion length is h, for example, t = 2.5 mm,
h = 4.2 mm, h is large with respect to t, and if a force is applied to the tip of the rib in the lateral direction, the rib easily deforms in the direction of the force.
(B) is a conceptual diagram showing a deformed state of the annular rib 354a when a cable 3 larger than the inner diameter of the annular rib 354a is inserted inside the annular rib 354a.

According to the experimental results of the present inventors, when the material is silicon rubber, the rib is easily bent and has a sealing property, and the ratio between the two, which does not cause aging, and the value of h / t is 1 , 5 or more and 6 or less.
If it is less than 1.5, it cannot be bent sufficiently. On the other hand, if it exceeds 6.0, the waist becomes weak and sufficient sealing properties cannot be obtained.

FIG. 3 is a cross-sectional view of a gasket showing a modification of this embodiment. The gasket shown in FIG. 1 is for a plurality of connectors and has a plurality of cable holes 353. An annular rib similar to that of FIG.
354a are formed, and these multiple cable holes 353a are formed.
, There is only one large outer peripheral surface, and the outer peripheral surface has the conventional linear projection 355 shown in FIG.
The same is formed. The position at which the linear projection 355 is formed is not particularly limited as long as it is intermediate in the longitudinal direction of the outer peripheral surface. Also, forming a plurality of linear projections 355 does not cause any particular problem, but forming too many linear projections 355 is not preferable because resistance increases at the time of insertion.

On the other hand, at least two, preferably two or more, circumferential annular ribs 354a provided on the inner peripheral surface of the cable hole 353 are provided at substantially equal intervals. Intermittent contact with the outer diameter produces a kind of labyrinth effect in addition to a mere sealing effect, and complete waterproofing can be realized. In addition, since the contact point with the cable is intermittent and the whole is softly tightened, deterioration of the cable coating does not progress, and the work of retightening the gasket is unnecessary. Further, the washer 36, which was required in the past, becomes unnecessary, and the intermediate portion of the annular rib 354a has a large diameter, so that the cable hole 353a is temporarily provided.
It is easy to widen the inner diameter of the cable and pass the large diameter portion of the cable end. Therefore, even after the work of crimping the contact to the cable end, the waterproof structure parts such as the tightening gland 31 and the gasket 35 can be connected to the cable 3. It is the same as the conventional one shown in FIG. 11 that the work procedure is not restricted.

Since the vicious cycle of tightening → cable outer shape deformation → retightening was cut off, long-term water resistance was maintained without retightening, and the result of the durability test was good. Although it is desirable to provide both the outer peripheral surface and the inner peripheral surface with the annular ribs 352a and 354a, as shown in FIG. 3, only the inner peripheral surface has a certain effect. [Embodiment 2] FIG. 4 is a cross-sectional view of a gasket 35 according to a second embodiment of the present invention, in which the same reference numerals are used, but the annular rib 352b on the outer peripheral surface and the annular rib 354b on the inner peripheral surface are different from each other. This is different from that of the first embodiment. Also in this case, the cross-sectional shapes of the annular rib 352b on the outer peripheral surface and the annular rib 354b on the inner peripheral surface are the same, and an enlarged partial sectional view of the annular rib 354b on the inner peripheral surface is shown in FIG.

First, as compared with that shown in FIG. 2, the entire rib is inclined in the axial direction, so that the cable can be easily inserted. (For the outer peripheral surface is easy insertion of the gasket 35 itself.) The second to have a thickness t ₂ of the tip relative to the root of the thickness t ₁ of the ribs slightly thinner, deformation is easy.
T ₁ = 1.5 mm, t ₂ = 1.0 mm,
h = 4.0 mm. By the way, the annular rib in the free state
The inner diameter of the tip of the 354b is 9.0mm, and the outer diameter is 11m.
m of cables are inserted.

The same applies to various multi-core gaskets such as two-core and multi-core gaskets.

[0027]

According to the present invention, a gasket which can be easily mounted and can maintain the waterproof performance for a long period of time is realized, and the performance of the electric connector is improved and the maintenance cost can be significantly reduced. It works.

[Brief description of the drawings]

FIG. 1 is a side view showing a gasket according to a first embodiment of the present invention in a partial cross section.

FIG. 2 is an enlarged partial sectional view of the gasket according to the first embodiment of the present invention.

FIG. 3 is a cross-sectional view of a gasket showing a modification of the first embodiment of the present invention.

FIG. 4 is a sectional view of a gasket according to a second embodiment of the present invention.

FIG. 5 is an enlarged partial sectional view of a gasket according to a second embodiment of the present invention.

FIG. 6 is a side view showing an example of a partial cross section of a socket in the electric connector according to the present invention.

FIG. 7 is a front view of the socket shown in FIG. 6;

FIG. 8 is a side view showing, in partial cross section, an example of a plug in the electric connector according to the present invention.

FIG. 9 is a cross-sectional view showing a part of a plug having a conventional waterproof structure.

FIG. 10 is an exploded side view showing a part of a plug having a conventional waterproof structure.

FIG. 11 is a side view showing a partial cross section of a conventional waterproof gasket.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Socket 2 Plug 3 Cable 11, 21 Casing 12, 22 Insulation stand 13 Socket contact 23 Pin contact 31 Tightening gland 32 Lock nut 33 Cable retainer 34 Ring 35 Gasket 36 Washer 351 Outer peripheral surface 352, 354 Annular rib 353 Cable hole 355, 356 Linear projection

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5E021 FA02 FA05 FA08 FB07 FB13 FB30 FC03 FC32 GB08 5E087 EE06 EE12 FF06 FF13 LL03 LL12 QQ04 RR06 RR12 RR25

Claims (4)

[Claims] An insulating table (12, 21) is provided in a casing (11, 21).
A clamping gland (31) screwed into a rear end of the casing (11, 21) in an electrical connector comprising a socket (1) and a plug (2) provided with contacts (13, 23) via the casing (22); (11, 21) A substantially cylindrical waterproof gasket (35) inserted in the middle of the rear end and inserted through the cable (3) connected to the contact (13, 23), A waterproof gasket for an electrical connector, wherein a plurality of annular ribs (354) are formed at substantially equal intervals in the axial direction on the inner peripheral surface of the cable hole (353). 2. An insulating table (12, 21) in a casing (11, 21).
A clamping gland (31) screwed into a rear end of the casing (11, 21) in an electrical connector comprising a socket (1) and a plug (2) provided with contacts (13, 23) via the casing (22); (11, 21) A substantially cylindrical waterproof gasket (35) inserted in the middle of the rear end and inserted through the cable (3) connected to the contact (13, 23), A waterproof gasket for an electric connector, wherein at least one annular rib (352) is formed at an axially intermediate portion of an outer peripheral surface (351). 3. An insulation table (12, 21) in a casing (11, 21).
A clamping gland (31) screwed into a rear end of the casing (11, 21) in an electrical connector comprising a socket (1) and a plug (2) provided with contacts (13, 23) via the casing (22); (11, 21) A substantially cylindrical waterproof gasket (35) inserted in the middle of the rear end and inserted through the cable (3) connected to the contact (13, 23), A plurality of annular ribs (354) are formed on the inner peripheral surface of the cable hole (353) at substantially equal intervals in the axial direction, and at least one annular rib (352) is provided at an axially intermediate portion of the outer peripheral surface (351). A gasket for waterproofing in an electric connector characterized by being formed. 4. When the thickness of the cross section of the annular ribs (352, 354) is t and the length of the protrusion is h, the ratio of h / t is 1.5.
The waterproof gasket according to any one of claims 1 to 3, wherein the gasket is not less than 6.0 and not more than 6.0.