JPS6115412Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an insulating cap for a glow plug.

Conventional examples of this type of insulating cap include those shown in FIGS. 1 and 2, for example. 1st
In the case of Figures A and B, a protrusion 1A is provided on the inner wall of the insulating cap 1, and the protrusion 1A is fitted into the screw groove of the electrode 3 protruding from the head of the glow plug 2, thereby fixing the insulating cap 1 to the glow plug 2. are doing. In addition, in the case of FIGS. 2A and 2B, the lower end of the insulating cap 4 is bent inward, and the bent part 4A is hooked onto the edge of the wire connection terminal 5 fixed to the glow plug 2. It is set to be fixed at 2. 6 is an electric wire, and 7 is a tightening nut.

However, in the former case, since the thread groove was not very deep, there was a problem in that the protrusion 1a easily came off from the thread groove. Further, in the latter case, since the wire connecting terminal 5 is wrapped around and fixed on the lower surface side of the terminal 5, there is a problem that the insulating cap 4 becomes relatively large.

This idea was made in view of the above circumstances.
A protrusion provided on the inner wall of the cap is engaged with the lower surface of the tightening nut on the glow plug head, and a protrusion that can come into contact with the upper surface of the nut is provided to prevent the cap from collapsing, making it compact and glow-proof. The purpose of the present invention is to provide an insulating cap that can be securely fixed to a plug.

Embodiments of the present invention will be described in detail below with reference to the drawings. Incidentally, the same parts as those in the conventional example are given the same reference numerals and the description thereof will be omitted.

3A and 3B show the insulating cap of this embodiment. In the figure, this insulating cap 11
is molded from a synthetic resin material that has electrical insulation and elasticity. One end of the insulating cap 11 is closed, and from the closed end side, an electrode covering part 11A, a nut covering part 11B having a larger diameter than the covering part 11A, and a skirt part that covers the upper surface of the wire connecting terminal 5 are formed in series. 11C. In addition, the electrode covering part 1
A plurality of, for example, three, protrusions 12 are formed protruding from the inner circumferential wall of 1A at approximately equal intervals. This protrusion 1
The protrusion 2 has a substantially right triangular shape with the hypotenuse extending from the inclined inner circumferential wall, and the lower surface of the protrusion 12 is formed so as to be able to come into contact with the upper surface of the tightening nut 7. Furthermore, a plurality of protrusions 13 are formed protruding from the inner circumferential wall of the nut covering part 11B in correspondence with the protrusions 12, and constitute a locking part that can be locked to the lower surface of the tightening nut 7.

When the insulating cap 11 having such a structure is attached to the head of the glow plug 2, it is pressed against the head from the open end of the cap. As a result, the opening end side of the tightening nut 7 touches the protrusions 13 on the outer periphery and expands slightly, and as it is further pressed, a plurality of protrusions 1
3 comes off from the outer periphery of the nut 7 and locks onto the lower surface of the tightening nut 7. In this state, the insulating cap 11 is firmly fixed to the head of the glow plug 2.
Further, the protruding electrode 3 is covered with an electrode covering part 11A, the outer periphery of the tightening nut 7 is covered with a nut covering part 11B, and the upper surface of the wire connecting terminal 5 is covered with a skirt part 11C.
The parts that require insulation can be mostly covered by the insulation caps 11. Furthermore, when the insulating cap is attached, a plurality of protrusions 1 provided on the inner circumferential wall of the electrode covering portion 11A
2 comes into contact with the upper surface of the tightening nut 7, so even if force is applied from the upper part of the cap, there is no worry that the cap 11 will be crushed and deformed. It won't come off.

In this insulating cap 11, since there is no need to provide a locking portion on the lower surface of the wire connecting terminal 5, the skirt portion 11C of the insulating cap 11 does not need to extend to the lower part of the wire connecting terminal 5. Therefore, less cap molding material is required, and the size of the cap itself can be made more compact.

As described above, according to the present invention, since the protrusion is engaged with the lower surface of the tightening nut screwed onto the electrode of the glow plug, the engagement area of the protrusion can be increased, and the engagement force of the insulating cap can be increased. It can be fixed in place. Therefore, its reliability can be improved. Furthermore, since a protrusion is provided that comes into contact with the upper surface of the nut to support the cap, there is an advantage that the cap is less likely to deform due to a force from above the cap and the locking portion is less likely to come off. Furthermore, since it is only necessary to cover the upper surface of the wire connection terminal, the cap shape can be made compact and the material cost can be reduced.

[Brief explanation of the drawing]

Figures 1 and 2 show conventional examples, and B
3 is a plan view, A is a vertical cross-sectional view, FIG. 3 is a bottom view, B is a cross-sectional view taken along the - arrow in FIG. 4, and FIG. 4 is a state of the glow plug device of the same embodiment. In the drawings, A is a plan view and B is a cross-sectional view taken along the - arrow direction of Fig. A. 2...Glow plug, 3...Electrode, 5...Wire connection terminal, 7...Tightening nut, 11...Insulating cap, 11A...Electrode covering part, 11B...Nut covering part, 11C...Skirt part , 12... protrusion, 13... protrusion (locking part).

Claims (1)

[Scope of utility model registration request] It is formed of a stretchable member having electrical insulation properties, has one end closed, and is connected in series from the closed end side to an electrode covering part that covers the protruding part of the electrode of the glow plug head, and an electrode covering part having a diameter larger than that of the electrode covering part. It has a nut covering part that covers the outer periphery of a tightening nut part that is screwed into the electrode, and a skirt part that covers the upper surface of the wire connection terminal that is tightened and fixed by the nut, and a plurality of protruding parts formed on the inner circumferential wall of the electrode covering part. a protrusion whose lower surface can come into contact with the upper surface of the tightening nut; a plurality of locking portions that protrude from the inner circumferential wall of the nut covering portion and are locked to the lower surface of the nut;
An insulating cap for a glow plug, characterized by being provided with.