JP2783165B2 - Rubber stopper for waterproof connector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rubber plug used for a waterproof connector.

[0002]

2. Description of the Related Art In a waterproof connector, a rubber stopper is used to prevent water from entering into an opening on the insertion side of a cavity into which a terminal fitting is inserted. FIG. 4 shows a conventional example of a rubber plug. This rubber plug 1 is formed by joining a cylindrical crimping portion 4 from one end surface of a cylindrical rubber plug main body 2 having a lip portion 3 formed on the outer periphery. It has a protruding shape. The rubber plug 1 is fixed to the terminal fitting by caulking the barrel 6 of the terminal fitting to the crimping part 4 with the electric wire 5 penetrating the rubber stopper main body part 2 and the crimping part 4 without any gap. When the rubber plug 1 is inserted into the cavity 7 together with the terminal fitting in such a state, the lip 3 on the outer periphery of the rubber plug main body 2 is brought into close contact with the inner periphery of the cavity 7 while being elastically deformed.
Water is prevented from entering the cavity 7 from between the inner periphery of the cavity 7 and the outer periphery of the rubber plug 1.

[0003]

When the rubber plug 1 is mounted in the cavity 7 and a bending force acts on the electric wire 5 extending from the opening side of the cavity 7 to the outside, the rubber plug 1 is bent inside the bend. Is deformed due to the compressive force acting from the electric wire 5, and as a result, a gap is formed outside the bend between the electric wire 5 and the inner periphery of the rubber plug 1 as shown in FIG. When a gap is formed between the electric wire 5 and the rubber plug 1 as described above, water penetrates into the space inside the cavity 7 in which the terminal fitting is accommodated by passing through the gap.

Therefore, as a countermeasure, a cylindrical portion is formed so as to be continuous with the opening outside the rubber plug main body, and the electric wire is passed through the cylindrical portion without any gap, and a bending force acts on the electric wire. In order to prevent a gap from being generated outside the bend when the bending is performed, a method can be considered. However, simply forming the cylindrical portion causes the pulling force from the electric wire to act on the rubber plug main portion via the cylindrical portion. As a result, the rubber plug main portion is elastically deformed outside the bend and the cavity is deformed. There is a possibility that a gap may be formed between the inner circumference and the inner circumference. Therefore, also in this case, the waterproof function is impaired.

The present invention has been made in view of the above circumstances, and has as its object to provide a rubber plug for a waterproof connector which can exhibit a high waterproof function against bending force from an electric wire. .

[0006]

As a means for achieving the above object, a rubber plug for a waterproof connector according to the first aspect of the present invention has a cylindrical shape through which an electric wire can penetrate and into which a terminal fitting is inserted. A rubber plug body is provided which is in close contact with the inner periphery of the cavity, and a cylindrical portion protruding from an end face of the rubber plug main body is provided, and an end surface of the rubber plug main body is connected to a base end outer periphery of the cylindrical portion. An annular groove is engraved in a portion to be formed, and the groove is formed such that its axis in the depth direction is oblique to the radial direction of the cylindrical portion and enters the rubber plug main body side. It is characterized by its structure.

A second aspect of the present invention is characterized in that, in the first aspect of the present invention, the groove is formed of a curved surface smoothly continuing to the outer periphery of the base end of the cylindrical portion.

[0008]

According to the first aspect of the present invention, when the cylindrical portion is bent and deformed by the bending force acting on the electric wire, the tensile force generated between the base end and the rubber plug main body due to the bending and deformation of the cylindrical portion. The force is relaxed and absorbed by the deformation of the groove.

According to the second aspect of the present invention, since a continuous portion between the groove and the base end of the cylindrical portion is continuous by a smooth curved surface, a stress generated when a bending force acts on the cylindrical portion is locally generated in this portion. Distributed without concentration.

[0010]

According to the first aspect of the present invention, the tensile force between the cylinder and the rubber plug main body is relaxed and absorbed by the groove. The rubber stopper main body is prevented from being pulled away from the inner periphery of the cavity, and has an effect that a reliable sealing function can be exhibited.

According to the second aspect of the present invention, the stress generated in the continuous portion between the groove and the cylindrical portion is dispersed.
It is possible to prevent the cylindrical portion from being broken from the rubber plug main body due to the local concentration of stress.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. The rubber stopper 20 of the present embodiment is
The rubber plug main body 21, a crimping portion 22 extending from one end of the rubber plug main body 21, and a cylindrical portion 23 extending from the other end surface 21A of the rubber plug main body 21 are integrally formed.

On the outer peripheral surface of the rubber plug main body 21, three circumferential lip portions 24 are formed at positions closer to the crimping portion 22 so as to be in close contact with the inner periphery of a cavity 31 described later. A large-diameter portion 25 that closes the opening 31 </ b> A of the cavity 31 is formed at a position on the outer peripheral surface of the rubber plug main body 21 on the side of the cylindrical portion 23. The hollow portion of the rubber plug 20 is an electric wire through hole 26 that opens at the distal end surface of the crimping portion 22 and the distal end surface of the cylindrical portion 23. On the inner periphery of the electric wire through hole 26,
Position of tip of cylindrical part 23 and crimping part 22 of rubber plug main part 21
A lip portion 2 that is in close contact with the outer periphery of the electric wire 32 at the side end position
7, 28 are formed.

The rubber plug 20 has a wire through hole 26
Then, the barrel of the terminal fitting (not shown) is crimped to the crimping portion 22 and the terminal fitting and the electric wire 32 are integrally assembled. The assembled state is inserted into the cavity 31. As shown in FIG. 2, in the state of being attached to the cavity 31, the outer peripheral lip portion 24 of the rubber plug main body 21 elastically deforms on the inner peripheral surface of the cavity 31 and adheres in a watertight state. The large-diameter portion 21 is in close contact with the inner peripheral surface and the outer surface along the edge of the opening 31A of the cavity 31 in a watertight manner, and closes the opening 31A of the cavity 31. Further, in the electric wire through hole 26 of the rubber plug 20, the lip portions 27 and 28 on the inner periphery thereof adhere to the outer periphery of the electric wire 32 in a watertight state while being elastically deformed. As a result, water cannot pass between the outer periphery of the rubber plug 20 and the inner periphery of the cavity 31 and between the inner periphery of the rubber stopper 20 and the outer periphery of the electric wire 32. Water is prevented from entering from the outside of the space 31 into the space on the back side in which the terminal fitting is housed.

The cylindrical portion 23 of the rubber stopper 20 of the present embodiment.
Is provided so as to protrude from the end face 21A of the rubber plug main body 21 on the side of the opening 31A in the state of being mounted in the cavity 31. The outer diameter of the cylindrical portion 23 is smaller than that of the rubber plug main body 21, and therefore, the cylindrical portion 23 is more easily bent than the rubber plug main body 21.

An annular groove 29 is formed on the end face 21A of the rubber plug main body 21 on the side where the cylindrical portion 23 is formed, along the outer periphery of the base end of the cylindrical portion 23. The groove 29 has an arcuate cross-sectional shape, and the inner peripheral edge of the groove 29 smoothly continues to the outer peripheral surface of the base end of the cylindrical portion 23.

Next, the operation of the present embodiment will be described.
When an external bending force acts on the electric wire 32 extending from the cylindrical portion 23, the cylindrical portion 23 elastically bends and deforms as the electric wire 32 bends. The bending force is relaxed and absorbed by the force. Also,
Outside the bend, the rubber plug body 21
A tensile force acts on the side, and the tensile force is relaxed by elastically deforming the portion constituting the inner surface of the groove 29 of the rubber plug 20 so as to expand the groove 29 as shown in FIG.・ Absorbed. Therefore, the pulling force hardly acts on the rubber plug main body 21, and the rubber plug main body 21 does not separate from the inner peripheral surface of the cavity 31 at both the large diameter portion 25 and the lip portion 24, The watertight state between the rubber plug main body 21 and the cavity 31 is maintained.

Further, when the electric wire 32 is bent, the cylindrical portion 23 is elastically bent and deformed integrally with the electric wire 32. Therefore, the electric wire 32 and the cylindrical portion 2 are bent outside the bend.
There is no gap between the inner periphery of the third member and the inner periphery of the third member. Particularly, in the present embodiment, the lip portion 27 is formed on the inner periphery of the tube portion 23, and the lip portion 27 bites the electric wire 32. Gaps are less likely to occur.

On the other hand, inside the bend, the rubber plug main body 21 and the cylindrical part 23 are only compressed by the electric wire 32, so that the space between the rubber plug main body 21 and the cavity 31 and between the cylindrical part 23 and the electric wire 32 There is no gap between them.

As described above, when the rubber plug 20 of the present embodiment is used, even if a bending force acts on the electric wire 32, the waterproofness between the rubber plug 20 and the cavity 31 and between the rubber plug 20 and the electric wire 32 are provided. Is maintained, and intrusion of water into the cavity 31 can be reliably prevented.

In this embodiment, since the groove 29 is smoothly continuous with the outer periphery of the base end of the cylindrical portion 23, when the wire 32 is bent at this portion, the tensile force from the cylindrical portion 23 side is obtained. The resulting stress is dispersed without being concentrated locally. Therefore, it is possible to prevent the cylindrical portion 23 from breaking from the rubber plug main body portion 21 due to local concentration of stress.

In this embodiment, the end face 21A of the rubber plug 20 exposed to the outside of the cavity 31 has a tapered shape protruding from the outer peripheral side toward the center.
The large diameter portion 25 covers the opening 31A of the cavity 31 from outside. Therefore, even if the opening 31A of the cavity 31 is mounted in a posture in which the opening 31A faces upward, the water outside the cavity 31 flows to the outer peripheral side on the end surface 21A according to the inclination of the taper, and the large-diameter portion 25
From the peripheral edge of the cavity 31 to the outside of the opening 31A of the cavity 31, it is possible to reliably prevent water from entering the cavity 31.

<Other Embodiments> The present invention is not limited to the embodiments described above with reference to the drawings. For example, the following embodiments are also included in the technical scope of the present invention. In addition, various changes can be made without departing from the scope of the invention.

(1) In the above embodiment, the case where the cross-sectional shape of the groove 29 is an arc is described, but the cross-section of the groove may be other shapes other than the arc.

(2) In the above embodiment, the groove 29 is
The case where the groove and the outer periphery of the base end of the cylindrical portion are not smoothly connected has been described.

(3) In the above embodiment, the rubber plug main body 21
Although the case where the large-diameter portion 25 covering the opening 31A of the cavity 31 is formed is described above, the present invention can also be applied to a rubber stopper having no large-diameter portion formed in the rubber stopper main body.

[Brief description of the drawings]

FIG. 1 is a sectional view of a rubber stopper according to an embodiment of the present invention.

FIG. 2 is a sectional view showing a state in which a rubber stopper is attached to a cavity.

FIG. 3 is a cross-sectional view showing a state in which a wire is bent.

FIG. 4 is a cross-sectional view showing a state in which a conventional rubber stopper is mounted in a cavity.

FIG. 5 is a cross-sectional view showing a state where a wire is bent in a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 20 ... Rubber stopper 21 ... Rubber stopper main body 23 ... Cylindrical part 29 ... Groove 31 ... Cavity 32 ... Electric wire

Claims (2)

(57) [Claims] 1. A rubber plug main body, which has a cylindrical shape through which an electric wire can penetrate, is closely attached to an inner periphery of a cavity into which a terminal fitting is inserted, and a cylindrical portion protruding from an end surface of the rubber plug main body. And an annular groove is engraved in a portion where the end surface of the rubber plug main body portion and the outer periphery of the base end of the cylindrical portion are connected,
The groove is formed such that an axis in a depth direction thereof is oblique to a radial direction of the cylindrical portion and enters the rubber plug main body side. 2. The rubber plug for a waterproof connector according to claim 1, wherein the groove is formed of a curved surface smoothly continuing to the outer periphery of a base end of the cylindrical portion.