KR101770149B1 - Glow plug - Google Patents

Abstract

A bracket having a through hole formed in a longitudinal direction thereof; And a pin assembly inserted into the through hole and coupled with the metal member, wherein the pin assembly includes a center shaft, A first knurl unit formed on an outer circumferential surface of an upper end of the middle shaft; A heating element that generates heat by energy transmitted through the center shaft; And a coil spring connecting the center shaft and the heating element.

Description

Glow plug {GLOW PLUG}

The present invention relates to a glow plug for preheating a combustion chamber to facilitate ignition of fuel in a diesel engine.

The diesel engine adopts a compression ignition method in which the mixed fuel is spontaneously ignited by reaching the ignition temperature instead of the method of sparking and igniting the flame forcibly. However, when air is compressed, leakage and heat loss occur, so that the pressure and temperature are lowered, which makes starting difficult. Thus, a glow plug is used to preheat the compressed air to reach its self-ignition temperature.

On the other hand, the terminal connection method for the glow plug has been changed from the conventional plate method to the connector fastening method for individual voltage supply and control diagnosis. Also, the glow plugs were attached and detached more frequently for individual maintenance. At the same time, due to the change of the shape of the pin assembly, the assembling direction of the bracket is changed, and the adapter is forced into the connector for caulking above the through hole of the bracket.

Specifically, the force applied to detach and attach the glow plug includes a torque that rotates clockwise or counterclockwise, and a twisting force is applied to the center shaft. This caused a crack in each welding portion in the glow plug and also caused a short circuit between the pin assembly and the metal fitting.

Korean Registered Patent No. 10-1115008 (Registered on Mar. 23, 2012) Korean Registered Patent No. 10-1115006 (Registered on Mar. 23, 2012) Korean Registered Patent No. 10-1315165 (Registered on September 30, 2013) Korean Registered Patent No. 10-0869714 (Registered on November 14, 2008)

SUMMARY OF THE INVENTION An embodiment of the present invention has been devised to solve the problems as described above, and it is an object of the present invention to provide a glow plug capable of preventing twisting force from being applied to the center axis. At the same time, it is intended to prevent cracks from being generated in the welded portion in the glow plug due to the torsional force. It is also intended to prevent the adapter from being easily released after caulking with the adapter. As a result, the manufacturing process can be simplified and the manufacturing cost can be reduced.

In order to solve the above-described problems, an embodiment of the present invention provides a metal mold comprising: a metal member having a through hole formed in a longitudinal direction thereof; And a pin assembly inserted into the through hole and coupled with the metal member, wherein the pin assembly includes a center shaft, A first knurl unit formed on an outer circumferential surface of an upper end of the middle shaft; A heating element that generates heat by energy transmitted through the center shaft; And a coil spring connecting the center shaft and the heating element.

An O-ring protruding through the upper through-hole of the metal fitting to seal the gap between the center shaft and the through-hole; And an insulating washer disposed on the upper side of the O-ring and being constrained to the center shaft and the metal fitting.

The first knurling unit may be a regular pattern arranged at a predetermined interval in the longitudinal direction of the central axis.

And a second nulling portion of a diamond pattern may be further formed on an outer circumferential surface of the intermediate shaft from the first nulling portion.

And an adapter having an upper end protruding through the upper through-hole of the metal fitting, the inner circumferential surface of the adapter being in tight contact with the second ring portion.

And a center pin disposed on the inside of the coil spring interposed between the extension and the heating element, wherein both ends of the center pin are in surface contact with the center shaft and the heating element, As shown in FIG.

As described above, according to the present invention, various effects including the following can be expected. However, the present invention does not necessarily achieve the following effects.

It is possible to form a first knurled portion of a straight pattern on the middle shaft upper end portion and to prevent the twisting force from being applied to the middle shaft by using the insulating washer which is inferiorly fitted to the first knurl portion. As a result, cracks can be prevented from being generated in the welded portion in the glow plug. Further, the second knurled portion of the diamond pattern can be formed to prevent the adapter from being easily separated after caulking.

1 is a perspective view of a glow plug according to an embodiment of the present invention;
2 is a sectional view of Fig. 1;
3 is an enlarged cross-sectional view of the vicinity of the locking bushing of Fig.
4 is a perspective view of a pin assembly according to an embodiment of the present invention;
5 is an enlarged sectional view of part D of Fig.
6 is an enlarged cross-sectional view of part C of Fig. 2;

Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a perspective view of a glow plug according to an embodiment of the present invention, FIG. 2 is a cross-sectional view of FIG. 1, and FIG. 3 is an enlarged cross-sectional view of a vicinity of a bushing of FIG. 1 to 3, the glow plug includes a bracket 10, a pin assembly 20, and an adapter 40.

The metal fitting 10 is a housing in which the pin assembly 20 is received and coupled, and a through hole 11 is formed in the longitudinal direction. That is, the components of the glow plug, including the pin assembly 20, are arranged and joined together through the inner hollow, which is generally cylindrical in shape of a pen. On the other hand, the metal member 10 is generally formed of a metal material.

In addition, a first step 13 may be formed at an intermediate portion of the metal fitting 10. To this end, the metal fitting 10 is formed with a second through-hole 11 (b) having an inner diameter larger than the inner diameter of the first through-hole 11 (a) and the first through-hole 11 (a). That is, the through hole 11 can be divided into the first and second through holes 11 (a) and 11 (b). Therefore, the first jaw 13 is formed due to a difference in step, that is, an inner diameter, between the first and second through-holes 11 (a) and 11 (b).

A washer groove is formed on the upper side of the through hole 11, that is, at the upper end of the first through hole 11 (a) so that the insulating washer 30 to be described later can be seated.

4 is a perspective view of a pin assembly according to an embodiment of the present invention. 4, when the electric energy supplied through the adapter 40 is transmitted along the central axis 21, the pin assembly 20 converts the heat energy into heat energy in the heating body 22 and provides it in the combustion chamber. At this time, the pin assembly 20 according to one embodiment is inserted into the through hole 11 of the metal fitting 10 and assembled to the metal fitting 10. The pin assembly 20 includes a center shaft 21, a heating element 22, a coil spring 23, and a center pin 24.

Here, the center shaft 21 is a long cylindrical shape made of a metal and is also called an inner polo. The upper end of the middle shaft 21 is exposed to the outside through the upper side of the through hole 11 of the metal fitting 10.

Next, the heat generating element 22 serves to provide thermal energy inside the combustion chamber. At this time, the exothermic temperature can be changed by design change. On the other hand, the heating element 22 is formed of a metal or a ceramic material. However, the heating element 22 according to one embodiment is preferably a ceramic heating element. At this time, the heating element 22 is in the form of a closed rod, and a U-shaped metal wire 26 is disposed therein.

Specifically, one end of the wire 26 is exposed through the upper outer circumferential surface of the heating element 22 to be electrically connected to the coil spring 23, and the other end is electrically connected to the sleeve 25 further coupled to the outer circumferential surface of the heating element 22 Lt; / RTI > As a result, the current flows into the one end of the wire 26 through the coil spring 23, and in particular, is converted into heat energy at the end of the heating element 22 to generate heat and flow out through the sleeve 25 .

The sleeve 25 is fixedly coupled to the outer circumferential surface of the heat emitting body 22 through which it is inserted by welding. The sleeve 25 is joined to the metal fitting 10 at the lower end of the through hole 11 by welding to fix the heating element 22 in the metal fitting 10.

Next, the coil spring 23 electrically connects the center shaft 21 and the heating element 22. In other words, both ends of the coil spring 23 are coupled to the respective ends of the center shaft 21 and the heat generating element 22, which are spaced apart from each other by a predetermined distance. The coil spring 23 is made of a metal material having an elastic force and capable of transmitting electrical energy.

When both ends of the coil spring 23 are fitted to the intermediate shaft 21 and the heat generating element 22, the joint portions are more firmly joined and fixed by welding. The welding can be, for example, laser welding or the like, but is not limited thereto. At this time, the center shaft 21 and the coil spring 23 are usually made of metal. However, the heating element 22 may be formed of a metal material or a ceramic material. Particularly, if the heating element 22 is made of a ceramic material, it is more preferable that an adhesive is applied to the joining portion due to a difference in a dissimilar material from the coil spring 23 and reinforced and fixed.

At this time, the center pin 24 is disposed inside the coil spring 23. That is, the center pin 24 is disposed inside the coil spring 23 so as to be interposed between the center shaft 21 and the heat generating element 22. At this time, both ends of the center pin 24 are in surface contact with the center shaft 21 and the heat generating element 22, respectively. That is, they are in contact with each other.

On the other hand, the center pin 24 is formed of a non-stretchable insulating material. As a result, the center pin 24 does not change its length even when the pressing force, that is, the compressive force, is applied. The center pin 24 may be formed by forcing the insulating washer 30 into the upper washer groove of the metal fitting 10 while the pin assembly 20 is inserted into the metal fitting 10, It is possible to prevent the middle shaft 21 from being pushed into the metal fitting 10 during the caulking process.

This is because the middle shaft 21 and the heat generating element 22 are connected by the coil spring 23 so that when the middle shaft 21 is pushed by the force applied from the upper end of the middle shaft 21, Can be. Then, the coil spring 23 and the inner circumferential surface of the metal fitting 10 come into contact with each other, causing a short-circuit phenomenon.

However, when the center pin 24 having a length corresponding to the distance between the center shaft 21 and the heat emitting body 22 is inserted into the coil spring 23, the center shaft 21 can not be pushed in. Therefore, 23 do not occur. At the same time, the caulking can be made uniform, and as a result, a constant caulking area can be ensured.

The adapter 40 is a portion to be fitted to the connector of the outer power supply portion. That is, the adapter 40 serves as a terminal for applying power to the glow plug. The adapter 40 is detachably attached to the connector while the control method for a plurality of glow plugs arranged in the diesel engine is changed to individual control. Thus, unlike the prior art, the adapter 40 can be detached from the connector only by applying a tensile force.

The pin assembly 20 according to another embodiment includes a center shaft 21, a locking bushing 27, a heating element 22, a coil spring 23 and a center pin 24. However, the remaining components are the same as those described above except for the middle shaft 21 and the bushing 27, and a detailed description thereof will be omitted.

At this time, the pin assembly 20 is inserted into the first and second through holes 11 (a) and 11 (b) and is engaged with the metal fitting 10. Specifically, the pin assembly 20 has a structure in which the upper end of the center shaft 21 is inserted through the second through hole 11 (b) and protruded outward through the first through hole 11 (a) Respectively.

On the other hand, the middle shaft 21 includes an upper middle shaft 21 (a) having a first outer diameter and a lower middle shaft 21 (b) having a second outer diameter larger than the first outer diameter. At this time, a second step 28 is formed between the upper and lower intermediate shafts 21 (a), 21 (b).

The engagement bushing 27 is interposed between the first and second jaws 13 and 28 when the pin assembly 20 is inserted into the metal fitting 10. The upper surface of the engagement bushing 27 is in contact with the first jaw 13 and the lower surface of the engagement bushing 27 is in contact with the second jaw 28. [ do. As a result, the pin assembly 20 to be inserted through the second through-hole 11 (b) is engaged with the first and second jaws 13 and 28 by the engagement bushing 27, Can be specified.

The locking bush 27 is preferably formed of an insulating material. As a result, the engagement bushing 27 can prevent a short circuit due to the contact between the intermediate shaft 21 and the metal fitting 10. When the pin bushing 27 is inserted into the metal fitting 10 and the pin assembly 20 is disposed in the metal fitting 10, the first and second through holes 11 (a) and 11 (b) In the center of the relationship.

In addition, the latching bushing 27 can prevent the pin assembly 20 from moving upward due to the tensile force generated when the adapter 40 is removed. In addition, the engagement bushing 27 can prevent the pin assembly 20 from moving in the bracket 10 according to the vibration of the diesel engine.

The middle shaft 21 according to another embodiment has an upper middle shaft 21 (a) having a predetermined first outer diameter and a tapered middle shaft (not shown) having a gradually increasing outer diameter at the upper middle shaft 21 And a lower intermediate shaft 21 (b) having a second outer diameter preset in advance in the middle of the tapered portion. At this time, the upper pivot shaft 21 (a) and the lower pivot shaft 21 (b) are the same as those described above, and a detailed description thereof will be omitted.

The tapered middle shaft is interposed between the upper middle shaft 21 (a) and the lower middle shaft 21 (b), and the tapered middle shaft is engaged with the engagement bushing 27. However, the position where the latching bushing 27 is hooked may vary depending on the size of the inner diameter of the latching bushing 27.

FIG. 5 is an enlarged sectional view of part D of FIG. 4, and FIG. 6 is an enlarged sectional view of part C of FIG. 5 and 6, the pin assembly 20 according to another embodiment includes a center shaft 21, a first null ring portion 62, a second null ring portion 64, a heating body 22, and a coil spring 23 ). Here, the center shaft 21, the heating element 22, and the coil spring 23 are the same as those described above, and the same reference numerals are used, and detailed description thereof will be omitted.

On the other hand, a second knurling 64 and a first knock ring portion 62 are formed in order on the outer peripheral surface of the upper end of the middle shaft 21 projecting from the upper end in the extending direction of the middle shaft 21. The first null ring part 62 is exposed through the upper side of the through hole 11 of the metal fitting 10 when the pin assembly 20 is arranged in the metal fitting 10. For example, the first nulling portions 62 may be a regular pattern arranged at predetermined intervals in the longitudinal direction of the center shaft 21. [ Alternatively, the first nulling portion 62 may be formed only on a part of the outer circumferential surface of the center shaft 21. [

At this time, a circular annular insulating washer 30 is press-fitted to the outer circumferential surface of the center shaft 21 on which the first null ring portion 62 is formed. The insulating washer 30 functions to absorb the torsional force applied to the center shaft 21, that is, to absorb the torque and buffer the torque. At this time, the insulating washer 30 is preferably made of a plastic material capable of elastic deformation.

On the other hand, the outer diameter of the insulating washer 30 is larger than the inner diameter of the metal fitting 10, and the inner diameter is smaller than the outer diameter of the middle shaft 21. As a result, the insulating washer 30 can be constrained between the center shaft 21 and the metal fitting 10. Specifically, since the insulating washer 30 has a soft material as compared with the first null ring portion 62, the interference fit portion is deformed corresponding to the shape of the first null ring portion 62. As a result, the coupling force between the insulating washer 30 and the middle shaft 21 can be further improved.

Further, when the insulating washer 30 is used, the upper washer groove of the metal fitting 10 can be sealed. At the same time, the insulating washer 30 makes it possible to maintain the insulation gap between the center shaft 21 and the metal fitting 10. As a result, a short circuit due to the contact between the center shaft 21 and the metal fitting 10 can be prevented. In addition, since the twist of the intermediate shaft 21 is reduced, it is possible to prevent the breakage of the coil spring 23 and the occurrence of cracks in the welded portion between the heat generating body 22 and the sleeve 25. [

On the other hand, an O-ring 32 made of a rubber material can be further inserted and inserted before the insulation washer 30 is deteriorated. Specifically, the O-ring 32 closes the gap between the middle shaft 21 exposed through the upper through-hole 11 of the metal fitting 10 and the through-hole 11. At this time, the O-ring 32 prevents penetration of other foreign matter such as moisture through the through hole 11 into the metal fitting 10.

A second null ring portion 64 of diamond pattern is further formed on the outer circumferential surface of the center shaft 21 from the first null ring portion 62 upward. As described above, the glow plug uses the adapter 40 to apply power to the pivot 21. That is, the adapter 40 is fitted to the second null ring portion 64 formed at the upper end of the middle shaft 21 protruding through the upper through hole 11 of the metal fitting 10. Accordingly, the inner circumferential surface of the adapter 40 is tightly engaged with the second null ring portion 64.

In addition, the pin assembly 20 is inserted through the lower through-hole 11 of the metal fitting 10, so that the possibility of torque being applied to the middle shaft 21 is low, especially during assembly. Also, when the adapter 40 is engaged or released, the torque does not act on the center shaft 21 largely.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the invention.

10: bracket 20: pin assembly
21: center shaft 22: heating element
23: coil spring 24: center pin
25: Sleeve 26: Wire
27: engagement bushing 62: first ring groove portion
64: second knurled portion 30: insulating washer
32: O-ring 40: Adapter
11: Through hole 11 (a): First through hole
11 (b): second through hole 21 (a): upper pivot
21 (b): lower pivot 13: first chin
28: second chin

Claims (6)

A bracket having a through hole formed in a longitudinal direction thereof; And
And a pin assembly inserted into the through hole and coupled with the metal fitting,
The pin assembly
Center axis; A first knurl unit formed on an outer circumferential surface of an upper end of the middle shaft; A heating element that generates heat by energy transmitted through the center shaft; And a coil spring connecting the center shaft and the heating element,
A second nulling portion of a diamond pattern is further formed on the outer circumferential surface of the center shaft from the first nulling portion upward,
And a center pin disposed between the center shaft and the heating element and disposed inside the coil spring, wherein the center pin is formed to have a length corresponding to an interval between the center shaft and the heating element, Wherein the center pin is in surface contact with the center shaft and the heating element, and the center pin is formed of a non-stretchable insulating material.
The method according to claim 1,
An O-ring protruding through the upper through-hole of the metal fitting to seal the gap between the center shaft and the through-hole; And
And an insulating washer disposed on the upper side of the O-ring so as to be pressed into the center shaft and the metal fitting.
The method according to claim 1,
Wherein the first knurling portion is a regular pattern arranged at a predetermined interval in the longitudinal direction of the center shaft.
delete The method according to claim 1,
And an adapter in which an upper end of the middle shaft projecting through an upper through hole of the metal fitting is fitted,
And an inner circumferential surface of the adapter is tightly engaged with the second null ring portion.
delete

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