JPS60159519A - Glow plug for diesel engine and manufacture thereof - Google Patents

Abstract

PURPOSE:To fix a nut to an electrode rod simply and surely by a method wherein a metallic nut is pinched from both sides thereof with one fitment having two pieces of caulking pawls and the other fitment having one piece of caulking pawl to push the bottom of an annular groove into centripetal direction from three radial directions to caulk and fix the nut to the electrode rod. CONSTITUTION:In order to fix a metallic nut 10, screwed to the electrode rod 5 extended from the rear end of a plug holder 2, the metallic nut 10 is formed with the annular groove 20 having a desired depth around the outer periphery thereof at the center in the axial direction thereof. The metallic nut 10 is pinched between the fitment 23, having two pieces of caulking pawls 21, 22, and the fitment 25, having one piece of caulking pawl 24, which are arranged opposingly from directions orthogonal to the axial direction at the outer peripheral section thereof while the bottom 20a of the annular groove is pushed centripetal direction from three radial directions to fix and secure it to the electrode rod 5. According to this method, the caulking forces are concentrated and the nut may be fixed to the electrode rod simply and surely by obtaining a sufficient securing force with small concentric forces.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a glow plug used for preheating an auxiliary combustion chamber or a combustion chamber of a diesel engine, and a method for manufacturing the same.

[Prior art]

In general, diesel engines have poor starting performance at low temperatures, so by installing a glow plug in the auxiliary combustion chamber or combustion chamber and generating heat by passing an electric current through it, it is possible to raise the intake air temperature or to use it as an ignition source. A method has been adopted to improve starting performance. This kind of glow plug has been known in the past with various structures.
Among them, the most common one is a coiled heat generating #i! inside a heat-resistant metal sheath! This is a so-called sheath type glow plug.

This will be briefly explained using a diesel engine glow plug to which the present invention is applied as shown in FIG. This is a metal plug holder held at the tip, and the rear end of this boulder 2 has ()
Ring 3 and 14 push': Electrode rod 5 via L4
are attached concentrically, and the tip of the pole 5 is inserted into the sheath 1. 1. Between the inner end of the electrode rod 5 and the tip 1 of the sheath 1, a coil-shaped heat generator IvJI6 made of a high melting point metal such as iron chromium or nickel is disposed 5jj. Both ends thereof are electrically connected to each other. Also, inside this sheath 1,
It is filled with heat-resistant insulating powder 7 such as magnet 7a, and part of the heating wire 6 and electrode rod 5 is buried therein. A threaded portion 2a is formed on the outer periphery of the front end of the holder 2 for screwing and fixing this glow plug into a hole 4-J (not shown) of the engine housing, and a threaded portion 2a is formed on the outer periphery of the rear end. The bolt part 2b, which has a hexagonal shape, is used for its installation.
It is formed as. Furthermore, 8 in the VC1 diagram is the heating wire 6
This is an insulator made of insulating material that serves as a guide.

Further, a metal nut 10 is screwed and fixed to the outer end of the electrode rod 5 for attaching a battery terminal, and a nut 13 for tightening is attached via a washer 11 and a spring washer 12. It is screwed on.

In such a configuration, when the electrode rod 5 is energized, the heating wire 6 is heated and generates heat by the supplied current, and the heat is transmitted to the sheath 1 via the heat-resistant insulating powder I, and as a result, The tip of the sheath 1 becomes red-hot f' and radiates heat into the combustion chamber, raising the temperature in the combustion chamber and improving the starting performance of the engine.

By the way, in the glow plug described above, the nut 1υ screwed onto the outer end side of the electrode rod 5 functions as a lead terminal attachment, and also serves as a flange portion 4a of the insulating bushing 4 on the rear end side of the holder 2. This is important in order to compress the O-ring 3 within the holder 2 with a desired pressing force between its inner wall and the outer periphery of the electrode rod 5 by pressing it against the holder 21111, thereby obtaining liquid tightness in this part. It is said that. Therefore, it has conventionally been possible to obtain a desired amount of ft't with respect to the mer electrode rod 5 using this nut 10tFIi method.
Fixing is done by fixing, but each method has its advantages and disadvantages.
It is difficult to say that it can be easily and appropriately identified.
There is hope that some kind of countermeasures will be taken.

For example, in Japanese Patent Application Laid-Open No. 56-37423, a circular nut 1 is shown in FIGS. 2 and 3 (a), (b)
4 to the electrode rod 50, the outer periphery of the central part of the nut 14 in the linear direction (tP+It) is pressed and clamped from both sides by the tightening jigs 15, 15, which are divided into two concave square parts. Here, tl shows a configuration in which the nut 14 is pressed uniformly in the center direction from four or more sides in the circumferential direction at the same time. However, if the crimping force is increased to 1゜, the cracks in this structure can be removed as shown in Fig. 3 (h).
As shown in Fig. 1, the peripheral edge of the pulley 14 is deformed and distorted in the axial direction, resulting in a high defect rate. As described above, when the nut 14 is displaced so as to expand in the axial direction, as shown in FIG.
There was a problem in that part a cracked and was damaged. The coil is oaked using the method described above) 14
In the case of staking, if a large press machine is required, the diameter of the nut cannot be made very large, and this is smaller than the inner diameter of the holder 2.
b I'm happy. When the nut 14 is deformed as described above, when tightening the lead terminals in contact with the outer surface of the nut 14, it is important to ensure reliable tightening.
Since it is a long type, it is necessary to tighten the nut 13 with a stronger force in order to make full contact with the terminal, and the installation becomes troublesome and causes problems.

[Summary of the Invention] The present invention has been made in view of the above-mentioned circumstances, and includes an annular groove formed on the outer periphery of the central part in the axial direction, extending from the rear end of the plug holder, and screwed onto the electrode rod. 7+) having a metal nut having two caulking claws arranged in relative amounts on the outer periphery thereof and one caulking claw)
The caulking force is applied to three points by the simple construction of clamping the annular groove from both sides using crimping fittings and pressing the bottom of the annular groove from three sides in the circumferential direction toward the center to fix the crimping to the electrode rod. The nut can be easily and securely fixed to the electrode rod by obtaining sufficient fixing force with a small amount of force throughout the year, and there is no deformation in the axial direction as in the conventional case, so there is no negative impact on other parts etc. We offer inexpensive glow plugs for diesel engines that do not have these problems.

[Example J Hereinafter, the present invention will be explained in detail using an example shown in the drawings.

FIG. 1 and FIGS. 5 to 8 show an embodiment of a closing lug for a diesel engine according to the present invention, and the general structure thereof is as described above, and a description thereof will be omitted.

According to the present invention, in order to easily and reliably fix the metal nut 10 to be screwed onto the electrode rod 5 extending from the rear end of the plug holder 2, the metal nut 10 is An annular groove 20 having a desired groove depth is formed on the outer periphery of the central part in the axial direction, and two grooves 20 are disposed on the outer periphery of the metal nut 10 facing each other from a direction orthogonal to the axial direction. Using a caulking metal fitting 23 having two caulking pawls 21 and 22' and a caulking metal fitting 25 having one caulking pawl 24, the annular groove bottoms 20a and 20f are pressed toward the center from three sides in the circumferential direction. The feature is that the caulking is fixed to the electrode rod 5.

To explain this in detail, the nut 10 made of scrap metal is formed of an aluminum material or the like so as to have a screw hole 10a at the center of the screw so as to have a substantially circular shape, and the outer periphery of the central part in the axial direction is An annular groove 20 whose surfaces are formed by tapered surfaces 20b and 20c is formed. In addition, this nut 1
As is clear from FIGS. 1 and 5, the outer diameter of the holder 2 is set to be larger than the inner diameter of the holder 2,
The outer surface of the insulating bushing 4 has a flange portion 4a (H
The groove bottom 20a of the annular e20 is smaller than the inner diameter of the holder 2, so that the pressing force when caulking this part can be minimized. It's well configured.

(7) In the nut 10 having the above-mentioned structure, force is applied from both sides of the nut 10 in a state where all electric power is aligned 5. Move the tightening metal fittings 23.25 completely and tighten the caulking claws 21.22:
By pressing the groove bottom 20a of the annular groove 2U with a 24G force from three directions in the circumferential direction, each part and the tightening claws 21 and 22 are pressed.
By effectively concentrating the tightening force on the three points where 24 hits, a sufficient fixing force can be achieved with a small force. 26 in the figure is the valley caulking pawl 2 at the annular groove bottom 20a.
1.22; 9 at the caulked part by 24, and 23a, 2
5a? This is the reference plane at the clamping position by the fittings 23 and 25.

Furthermore, the tapered surfaces 20b and 2Uc on both sides of the annular groove 20 of the nut 10 described above are connected to the claws 21. of the respective metal fittings 23.25.
22:24 to the groove bottom 20a, and guarantees the strength of both valve edges of this nut 1υ.
This can also be effective in preventing displacement in the axial direction during the caulking process described above.

In addition, the second bracket 23.25 of the double oak is the 9th fl.
(a) (b) (c) t: or Figure 1O (a) (b)
As is clear from (c), the entire plate is formed of steel or the like so as to have a flat plate shape, and a caulking pawl 21°22:24 is provided on the inner end side, and a groove is provided on the outer end side. As shown in Fig. 11, bottle holes 23b and 25b are drilled to be connected to the drive system of the closing machine 3 [J1'itl].

The schematic structure of this caulking@30 will be briefly explained using FIG. 11. In the figure, 31 is a gear having hexagonal holes 31a to 31f for holding the holder bolt part 2b of the glow plug, and 32 is a gear meshing with this gear 31. This rack 32 has a reciprocating portion B1b in the direction of the paper, and a piston rod 3 is connected to the rack 32.
3a k connected hydraulic cylinder 33, a pneumatic cylinder 34 that sends a predetermined oil pressure to this cylinder 33, and an electromagnetic switch that sends air pressure from the air tank 35 to the air pressure chamber 34a of this cylinder 34 or the rod side chamber 33b of the cylinder 33. It is driven by a retightening mechanism for the nut 10 made of pulp 36 or the like. Note that the sudden force of the h1 rack 32 is applied to the hydraulic pipes of both cylinders 33 and 34.
A variable throttle 37 is provided to prevent total displacement, and a check valve 38 is installed in parallel with this to prevent reverse 5Lk of hydraulic pressure. Sorry, this retightening machine 14: ttx, tighten the tightening metal fittings 23 as described later.
25, 6 claws 21, 22:24i' The nut 10 held by the trowel can be relatively released by rotation of the holder 2 side.

On the other hand, the force/clamp fittings 23.25 are connected to the piston rods 4 of the first and second pressure cylinders 40.41, respectively.
0a, pins 42a of connectors 42, 43 at the tips of 41a,
43a' ([-), and these two cylinders 40, 41 are configured to move forward and backward with respect to the nut 1υ. That is, both the cylinders 40.
41 is a pressure regulating valve 45 for low pressure or heavy pressure from an air tank 44 (which may be the same as the previous IC air tank 35).
．． It is driven by an actuator 4T which is driven by air pressure supplied through a hydraulic line 46 to send out a desired hydraulic pressure, and a pressure gauge 49 is attached to the hydraulic line 4B.

Additionally, a check valve 5u for preventing backflow is provided downstream of the pressure regulating pulp 45 for low pressure, and a first switching pulp 51 is provided downstream of the pressure regulating pulp 46 for high pressure. A pneumatic line 52 leading to the actuator 47 is provided with a second switching pulp 53 and a three-way switching valve 54 .

The three-way switching valve 54 has a configuration roughly shown in FIG. 12, and when the nut 10 is fixed and tightened, the valve body 55 is moved from the first valve seat 56 to the second valve seat 57IllI. It is operated so that air can be supplied to the entire actuator 4T side by making contact with it, and when removing the caulking fittings 23, 25'ffi, the valve body 55 is pressed by the spring 58 toward the first valve seat 56 side, It operates to open the actuator 47 system to the atmosphere. In addition, in Fig. 11, the tip of the type T rod 5 extending to the lower end of the glow plug is held by a guide member 60, and furthermore, a nut 10 is caulked on the outside thereof (not shown). A cylinder is provided that allows the glow plug to be lifted up and removed after completion.

Such a tightening machine 30u may be operated as follows.

1. After screwing the nut 1 () onto the electrode rod 5 of the glow plug that has been assembled in advance and temporarily tightening it, the L2 cutting gear 3
1 into the hexagonal hole 31a. At this time, if this set is performed using a robot hand, the effect on automation will be great.

Next, only the second switching pulp 53 is turned on and opened, and a low air pressure of, for example, 2.5 kp/aη is supplied to the actuator 47 from the low pressure regulating valve 45 L, and each pressurizing cylinder 40.41 'e Activate 1
)l, crimping claw 21゜22:24' of fitting 23.25
Annular groove bottom 20a of t-nut 10, fT! 1 with a force of, for example, 650 kLa degrees. At this time, the six claws 21, 22: 24 of K are brought into contact with a force that does not swage the nut 10.

Thereafter, the retightening mechanism is activated to retighten the nut 10 to the electrode rod 5 with a specified torque of about 201 v-cm, and in this state, the first switching pulp 51 is turned on to adjust the pressure for high pressure. Pulp 46 to 4.5 ky/c
Air pressure as high as rt+ is supplied to the actuator 47 side. Then, the high hydraulic pressure generated by this actuator 47 is sent to the cylinder 40.41, and the six pawls 2
1.22:24 Gold The nut 10 is pressed even harder, for example, with a force of about 9 to 1200, resulting in the three-point caulking of the nut 10 as described above.

After the caulking process described above is completed, the switching pulp 51
．． 53'? : Turn off to stop the supply of air pressure, release the air pressure to the atmosphere with the three-way switching valve 54, return each pressurizing cylinder 40, 41 to the initial state, and move the six claws 21, 22: 24 out of the nut 10. let At this time, the air between the switching pulp 51, 53 and the check pulp 50 is trapped, but this is due to the small diameter of the pipe, so when the next manual tightening operation is performed, the air is trapped in the actuator 4T. Absorbed.

In addition, at the end of the above-mentioned operation, the retightening machine (18
The rack 32 is returned to its original position. At this time, the glow flag is rotated together with the gear 31 because the claws 21, 22; 24 are outside t1 from the nut 10.

Then, the glow plug of the peak is removed from the set state by Clifting it to the lower cylinder, and being removed by a robot hand, etc., to complete the process. ``Can be done automatically
Third, it is superior in terms of mass production and cost.

Note that the present invention is not limited to the structure of the embodiment described above, and is free to modify and change the shape and structure of each part as appropriate.In short, the annular groove of the metal nut screwed onto the electrode rod Press down on the bottom with three swiveling nails,
The fitting is fine as long as it is fixed.

〔Effect of the invention〕

As explained above, in this invention, a metal nut having an annular groove on the outer periphery of the central part in the axial direction and screwed onto the electrode rod extending from the rear end of the plug holder is attached to the outer periphery of the plug holder. The bottom of the annular f/II groove is clamped from both sides using a crimping fitting having two crimping claws arranged opposite to each other and a force/clamping fitting having one crimping claw, and Since the caulking is fixed to the electrode rod by pressing in the center direction from the center, the caulking force is concentrated in three points and a sufficient fixing force can be obtained with a small force, despite the simple and inexpensive structure. can be easily and reliably fixed to the electrode rod, and since there is no deformation in the axial direction as in the conventional case, there is no problem of adverse effects on other parts. As a device for caulking, it has a simple structure, can automate all sub-works, and can be mass-produced at low cost without using human hands, and has various excellent effects.

[Brief explanation of the drawing]

Fig. 1 shows a longitudinal side view of an embodiment of a diesel engine glow plug according to the present invention, and Fig. 2 is a schematic diagram showing a conventional example of tightening a metal nut onto an electrode rod. Figures 3(a) and 3(b) are diagrams showing the manufacturing method, 141-discharge conventional 0 defect present + gong, Figure 4 is an enlarged sectional view of main parts showing conventional defects, and Figure 5 is An enlarged sectional view of the main part of the present invention, FIG. 6(a), (
b) Figures 7(a) and 7(b) are a plan view and a sectional view thereof showing the relationship between the metal nut and its caulking fitting, which characterizes the present invention, and the crimped L2 state, and Figure 8 is a sectional view thereof.
・Cross-sectional view of the tightened metal nut, Figure 9 (a3
, (b), (c) and IHo diagram (a),
(b). (c) is a plan view, a cross-sectional view, and an enlarged view of the main parts of the caulking metal fitting, FIG. 11 is a diagram showing the schematic configuration of the device for applying the manufacturing method according to the present invention, and FIG. 12 is the three-sided pulp. Let's look at a diagram that illustrates this. 1・◆War・Sheath, 2・・−ψF”lug holder, 3・・
-・0 ring, 4・9・insulation bushing, 5・・electrode rod, 6・・heating wire, 10・・・metal nut,
11... washer, 12... Φ spring washer, 13... tightening nut, 20... annular groove, 20a... groove bottom, 20b, 20c fist...
Tapered surface, 21°22:24---Caulking claw, 23.
25---・〃・Tightening fittings, 30・・・・Force/tightening machine. Special Ff LI applicant Masaki Yamakawa (and 2 other people) Agent of Automotive Equipment Co., Ltd. Figure 1 Figure 3 (a) (b) Figure 4 Figure 5 Figure 6 (0) (b) Figure 7 ( 0) (b) - Figure 8 Figure 9 (b) (C) 3- Figure 10 (Q) ? CI (b) (C) Figure 11/, Q Figure 12 1r f- Written amendment for truncated procedure (voluntary) Mr. Commissioner of the Japan Patent Office, 1920/3/15 1. Indication of the case 1982 Patent item No. 14678 and its manufacturing method 3, relationship with the amended case Patent Applicant name (name) Jidosha Kiki Co., Ltd. Above Figure 7 (0)

Claims (2)

[Claims] (1) A gold FS nut is attached to the electrode rod extending from the rear end of the plug holder. A glow plug for a diesel engine, characterized in that the groove bottom of the annular groove is fixed to the electrode rod by pressing from three sides toward the center in the circumferential direction and caulking. (2) Screwed onto an electrode rod extending from the rear end of a metal Naratra plug holder having an annular groove on the outer periphery of the central portion in the axial direction, and facing the annular groove bottom of the nut. From the direction perpendicular to the axial direction to the relative direction (
1. Arrange the caulking metal fittings with two caulking claws and the caulking metal fittings with one caulking pawl, and then move these inner metal fittings toward the nut to center three locations in the circumferential direction of the nut. A method of manufacturing a glow plug for a diesel engine, which comprises pressing and caulking the nut onto an electrode rod.