CN102629734B - Spark plug and manufacture method thereof - Google Patents
Spark plug and manufacture method thereof Download PDFInfo
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- CN102629734B CN102629734B CN201210022312.3A CN201210022312A CN102629734B CN 102629734 B CN102629734 B CN 102629734B CN 201210022312 A CN201210022312 A CN 201210022312A CN 102629734 B CN102629734 B CN 102629734B
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Abstract
The invention provides a spark plug and a manufacture method thereof, which can raise the resistance to grounding electrodes. The spark plug (1) is provided with an insulator (2) which has an axle hole (4) passing through an axle direction (CL1), a central electrode (5) inserted on one side of a front end of the axle hole (4), a main body part (3) arranged on the periphery of the insulator and a grounding electrode (27) arranged on the front part of the main body part and bending towards one side of the central electrode through a bending part (27C) of the grounding electrode. In the bending part, a recess part (29) extending in a long side direction of the grounding electrode is formed on at least part of a back side (27b) and two sides (27s1, 27s2) of the grounding electrode; in a cross section orthogonal to a central axle of the grounding electrode, the hardness of the bottom (29b) of the recess part (29)is greater than the hardness of a central part of one side of the central electrode (5).
Description
Technical field
The present invention relates to the spark plug and manufacture method thereof that use in the burners such as a kind of internal combustion engine.
Background technology
Spark plug is such as installed on internal combustion engine (engine), for lighting a fire to the mist in combustion box.Generally, spark plug has: the insulator with axis hole; Be inserted through the central electrode of the side, front end of this axis hole; Be arranged on the main metal fixture of insulator periphery; With the grounding electrode that the leading section of main metal fixture is combined.Grounding electrode, in the bend of roughly mid portion being arranged at self, makes leading section and central electrode relatively bend and turns back, between the leading section and the leading section of central electrode of grounding electrode, form spark-discharge gap.Further, by applying high pressure to central electrode, produce sparkover at spark-discharge gap, (such as with reference to patent documentation 1 etc.) is lighted a fire to mist.
Patent documentation 1: JP 2008-108478 publication
Summary of the invention
And in recent years, require the miniaturization of spark plug, path, in order to can be combined with the main metal fixture of path, require that grounding electrode is comparatively thin, or the radius of curvature of bend is less.Further, in high output engine in recent years, because of vibration etc., the stress being applied to grounding electrode (especially bend) is larger.Namely there is following situation: the grounding electrode that intensity is the lower or stress of having to easily focuses on bend is easily occurring to use under its harsh and unforgiving environments lost.Therefore, the resistance to property lost improving grounding electrode is further required.
The present invention occurs in view of the above circumstances, and its object is to provides a kind of spark plug and the manufacture method thereof that can improve the resistance to property lost of grounding electrode tremendously.
Be described being suitable for each formation subitem realizing above-mentioned purpose below.In addition, as required, its distinctive action effect is recorded to the formation of correspondence.
Form 1. spark plugs formed to have:
The insulator of tubular, has at the through axis hole of axis direction;
Central electrode, inserts the side, front end being set to above-mentioned axis hole;
The main metal fixture of tubular, is arranged on the periphery of above-mentioned insulator; And
Grounding electrode, is configured in the leading section of aforementioned body accessory,
Above-mentioned grounding electrode passes through the bend of self to above-mentioned central electrode curving,
The feature of above-mentioned spark plug is:
In above-mentioned bend, being positioned at and the going up at least partially of the back side of the above-mentioned grounding electrode of above-mentioned central electrode opposite side and two sides adjoining with this back side, be formed in the recess that the long side direction of above-mentioned grounding electrode extends,
In the cross section of the orthogonality of center shaft with above-mentioned grounding electrode, in above-mentioned grounding electrode, the hardness of the bottom of above-mentioned recess is greater than in above-mentioned grounding electrode the hardness of the middle body in the face being positioned at above-mentioned central electrode side.
According to above-mentioned formation 1, be provided with in the back side of grounding electrode or side in bend the recess that the long side direction along grounding electrode extends at least partially, the hardness of the bottom of recess is greater than in grounding electrode the middle body in the face being positioned at central electrode side (namely forming the position that firmness change does not occur substantially along with recess).Therefore, can effectively improve the intensity that stress is especially easy to concentrated bend in pole, improve the resistance to property lost of grounding electrode tremendously.
Further, also can consider on the face of central electrode side, to arrange recess in grounding electrode, but when arranging recess on the face of this central electrode side, easily generation take recess as the fracture of basic point.Therefore, from the angle conscientiously improving the resistance to property lost, preferably recess is set in the back side of grounding electrode, side.
Further, also can consider not arrange recess, by pushing the Zone Fulls such as the side of grounding electrode, increasing the hardness in the whole regions such as the side of grounding electrode, but in this case, the increase of manufacturing cost may be caused.Therefore, at least increase the hardness of the bottom of recess while arranging recess, the angle effectively improving the resistance to property lost while rising from suppressing manufacturing cost is comparatively preferred.
The feature forming the spark plug that 2. are formed is that, in above-mentioned formation 1, above-mentioned recess is formed in the whole region of the long side direction of above-mentioned bend.
According to above-mentioned formation 2, can intensity be improved in the whole region of bend, improve the resistance to property lost of grounding electrode further.
The feature forming the spark plug that 3. are formed is, in above-mentioned formation 1 or 2, in the cross section orthogonal with the long side direction of above-mentioned grounding electrode,
If the degree of depth of above-mentioned recess is D (mm), above-mentioned grounding electrode along the thickness of the depth direction of above-mentioned recess be TD (mm), above-mentioned recess wide for W (mm), above-mentioned grounding electrode be TW (mm) along the thickness of the Width of above-mentioned recess time, meet following formula (1) and
(2)：
0＜D≤TD/2……(1)
TW/20≤W＜TW……(2)
In addition, when two sides of grounding electrode form recess respectively, " degree of depth of recess " refers to the summation of the degree of depth of each recess.
According to above-mentioned formation 3, while can fully maintaining the thickness of grounding electrode, conscientiously improve the hardness of bottom further.That is, while can preventing the intensity of grounding electrode from declining more effectively, the intensity of bend is improved.Result can further improve the resistance to property lost.
The feature forming the spark plug that 4. are formed is in above-mentioned formation 3, meet following formula (3) and (4):
TD/6≤D≤TD/3……(3)
TW/6≤W≤TW/3……(4)
According to above-mentioned formation 4, conscientiously can improve the hardness of bottom further, improve the intensity of bend further.Result can realize the resistance to property lost good further.
Forming 5. features of spark plug formed is, above-mentioned recess is respectively formed at above-mentioned two sides of above-mentioned grounding electrode in any one of above-mentioned formation 1 to 4.
According to above-mentioned formation 5, form recess in two sides of grounding electrode, therefore become the form that grounding electrode is clamped by two recesses, the bottom hardness of recess can be increased.Result can further improve the resistance to property lost.
The manufacture method forming the spark plug that 6. are formed is the manufacture method of the spark plug described in any one of above-mentioned formation 1 to 5, it is characterized in that,
Comprise: bending operation, above-mentioned grounding electrode forms above-mentioned bend; And
Recess formation process, above-mentioned grounding electrode forms recess,
After above-mentioned bending operation, carry out above-mentioned recess formation process.
When forming recess before bending grounding electrode, along with bending of grounding electrode, bottom hardness may reduce.For this point, in above-mentioned formation 6, its formation has formed recess after having bent grounding electrode.Therefore, can conscientiously prevent hardness from declining, improve the resistance to property lost further.
Accompanying drawing explanation
Fig. 1 is that the part of the formation representing spark plug blocks front view.
Fig. 2 is the amplification front elevation of the formation of the leading section representing spark plug.
Fig. 3 is the enlarged partial cross section of the cross sectional shape representing recess.
Fig. 4 (a), (b) are the enlarged partial cross section of other examples representing the face forming recess.
Fig. 5 (a) ~ (c) is the part amplification front elevation of other examples of the forming range representing recess.
Fig. 6 (a) ~ (c) is the enlarged partial cross section of other examples of the cross sectional shape representing recess.
Fig. 7 is the figure representing the fixture that uses in recess formation process etc., and (a) is amplification plan view, and (b) is amplification front elevation.
Embodiment
Referring to accompanying drawing, an execution mode is described.Fig. 1 represents that the part of spark plug 1 blocks front view.And in FIG, using the axis CL1 direction of spark plug 1 as the above-below direction in accompanying drawing, using downside as the side, front end of spark plug 1, upside is described as side, rear end.
Spark plug 1 by as insulator insulating part 2 and keep its main metal fixture 3 etc. of tubular to form.
Insulating part 2 is well-known by firing the formation such as aluminium oxide, its profile portion has: the columned rear end side main part 10 being formed in rear end side; The large-diameter portion 11 in front to radially outstanding formation is compared with this rear end side main part 10; Compare with this large-diameter portion 11 footpath thinner than it, front formed in main part 12; The considerable portion 13 formed to footpath thinner than it in front is compared with main part in this 12.Further, in insulating part 2, large-diameter portion 11, middle main part 12 and most of considerable portion 13 are housed in the inside of main metal fixture 3.Further, the connecting portion in middle main part 12 and considerable portion 13 is formed the end difference 14 of taper, and by this end difference 14, insulating part 2 engages to main metal fixture 3.
Further, in insulating part 2, be formed through axis hole 4 along axis CL1, insert in the side, front end of this axis hole 4, be fixed with central electrode 5.Central electrode 5 is formed by nickel (Ni) alloy, overall in bar-shaped (cylindric).Further, the front end face of central electrode 5 is formed flatly, and gives prominence to from the front end of insulating part 2.In addition, the inside of central electrode 5 also can arrange the internal layer be made up of the copper with good thermal conductivity, copper alloy.Now, the thermal diffusivity of central electrode 5 improves, and can improve resistance to expendable.
Further, in the rear end side of axis hole 4, terminal electrode 6 inserts with the state that the rear end from insulating part 2 is outstanding, fixes.
Further, between the terminal electrode 6 of the central electrode 5 of axis hole 4, configure columned resistive element 7.The both ends of this resistive element 7 are electrically connected to central electrode 5 and terminal electrode 6 respectively by the glass seal layer 8,9 of conductivity.
And, aforementioned body accessory 3 is formed as tubular by metals such as low-carbon steels, its outer peripheral face is formed the threaded portion (outer screw section) 15 (such as diameter of thread M14) being used for spark plug 1 being installed to the burner such as internal combustion engine or fuel cell modification device.Further, the outer peripheral face of the rear end side of threaded portion 15 is formed the seat portion 16 of the blade of a sword shape to the outstanding formation of radial outside, in the head of screw 17 of rear end, threaded portion 15, be embedded with the packing ring 18 of annular.Further, be provided with in the rear end side of main metal fixture 3 and be used for making the hexagonal tool engagement portion 19 in the cross section of the tool engagement such as spanner when spark plug 1 is installed to burner.Further, the caulking part 20 be bent to form to radially inner side is set in the rear end side of tool engagement portion 19, keeps insulating part 2 by this caulking part 20.
Further, the inner peripheral surface of main metal fixture 3 is arranged the end difference 21 of the taper for engaging insulating part 2.And, insulating part 2 inserts side forward from the rear end side of main metal fixture 3, under the state of end difference 21 that the end difference 14 of self engages to main metal fixture 3, the peristome of the rear end side of main metal fixture 3 is riveted to radially inner side, namely form above-mentioned caulking part 20, thus be fixed to main metal fixture 3.In addition, there is circular sheet material filler 22 between above-mentioned two end differences 14,21.So, can keep the sealing in combustion box, the fuel gas entering into the gap between the considerable portion 13 of the insulating part 2 be exposed in combustion box and the inner peripheral surface of main metal fixture 3 can not leak into outside.
Further, for making the sealing based on riveted joint comparatively perfect, in the rear end side of main metal fixture 3, between main metal fixture 3 and insulating part 2, there is annular element 23,24, and between annular element 23,24, filling talcum (タ Le Network) 25.That is, main metal fixture 3 keeps insulating part 2 by sheet material filler 22, annular element 23,24 and talcum 25.
Further, in conjunction with grounding electrode 27 on the leading section 26 of aforementioned body accessory 3, this grounding electrode 27 is formed by Ni alloy, and has substantially identical width and thickness along self long side direction.This grounding electrode 27 is by being formed in the bend 27C of the roughly middle bending (non-linear shape) of self, and turn back to central electrode 5 curving, its leading section is relative with the leading section of central electrode 5.Further, between two electrodes 5,27, form spark-discharge gap 28, in this spark-discharge gap 28, roughly produce sparkover along axis CL1 direction.In addition, in the present embodiment, the area of the front end face of main metal fixture 3 is less.Therefore, the sectional area of the base end part of the grounding electrode 27 be combined with the leading section 26 of main metal fixture 3 also less (being such as below 4.48mm2).
And as shown in Figures 2 and 3, grounding electrode 27 has: the back side 27b being positioned at the opposite side of central electrode 5; Two side 27s1, the 27s2s adjacent with this back side 27b, in the present embodiment, from the base end side of two sides 27s1,27s2 to front end, form the recess 29 of the concavity that the long side direction along grounding electrode 27 extends.That is, recess 29 is formed in the whole region of the long side direction of above-mentioned bend 27C.
Further, recess 29 in the cross section orthogonal with the long side direction of grounding electrode 27, in cross section V shape.And, recess 29 in present embodiment is by implementing plastic working to grounding electrode 27 and forming (manufacture method is aftermentioned), therefore the hardness of the bottom 29b (namely implementing the position of plastic working) of grounding electrode 27 center dant 29, is greater than in grounding electrode 27 hardness of the middle body (namely not implementing the position of special processing) in the face being positioned at central electrode 5 side.In addition, bottom 29b refers to, in recess 29, from the forming surface (being side 27s1,27s2 in this example) of the recess 29 grounding electrode 27 along the depth direction position farthest of recess 29.
Further, recess 29 meets following two formula ground formation respectively.Namely, if the degree of depth of recess 29 is D (mm), grounding electrode 27 along the thickness of the depth direction of recess 29 be TD (mm), recess 29 wide for W (mm), grounding electrode 27 be TW (mm) along the thickness of the Width of recess 29 time, form with meeting 0 < D≤TD/2 (preferred TD/6≤D≤TD/3) and TW/20≤W < TW (preferred TW/6≤W≤TW/3).In addition, " degree of depth D of recess 29 " is formed in the summation of the degree of depth of each recess 29 on two sides 27s1,27s2.
Further, the position arranging recess is not limited to above-mentioned two sides 27s1,27s2, and at least one side in above-mentioned back side 27b and two side 27s1,27s2 arranges recess.Therefore, as shown in Fig. 4 (a), a face in two sides 27s1,27s2 can arrange recess 31, also as shown in Fig. 4 (b), 27b can be arranged recess 32 overleaf.Further, also from back side 27b to side 27s1, (side 27s2) recess can be set.
And, also from the base end side of grounding electrode 27, recess can not be set to front end, and as shown in Fig. 5 (a), in grounding electrode 27 only corresponding bend 27C forming range recess 33 is set, also can as shown in Fig. 5 (b), only a part of corresponding bend 27C arranges recess 34.Further, also recess can be set discontinuously, and as shown in Fig. 5 (c), the long side direction along grounding electrode 27 arranges recess 35 discontinuously.
Further, the cross sectional shape of recess is not limited to V shape, can as shown in Fig. 6 (a), and cross section rectangular area forms recess 36, also as shown in Fig. 6 (b), can form recess 37 section flexure shape (such as cross section semicircle shape).Further, also can as shown in Fig. 6 (c), cross section ladder topography becomes recess 38.
The manufacture method of spark plug 1 as above is then described.
First, main metal fixture 3 is processed in advance.That is, by implementing cold rolling forging processing etc. to columned metal material (ferrous material, stainless steel material that such as S17C, S25 are such), form through hole, and produce approximate shape.Setting profile to order by implementing cut afterwards, obtaining body element intermediate.
Then, to the directly bar-shaped grounding electrode 27 that the front end face resistance welded of main metal fixture intermediate is made up of Ni alloy.When carrying out this welding, producing so-called " drip ", therefore after eliminating this " drip ", forming threaded portion 15 in the predetermined portion of main metal fixture intermediate by rolling forming.So, the main metal fixture 3 of having welded grounding electrode 27 can be obtained.Further, zinc-plated or nickel plating is implemented to the main metal fixture 3 of having welded grounding electrode 27.In addition, for improving corrosion resistance, chromate process can be implemented further to its surface.
On the other hand, independent of aforementioned body accessory 3, processing and forming insulating part 2.Such as, use with aluminium oxide and be main body and material powder containing adhesive etc., modulation molding material granules, use it to carry out rubber press shaping, thus the formed body of tubular can be obtained.Further, attrition process is implemented to the formed body obtained, finishing appearance, implement on this basis to fire processing, thus obtain insulating part 2.
Further, by implementing forging processing to Ni alloy, central electrode 5 is produced.
Further, the insulating part 2 as above obtained and central electrode 5, resistive element 7, terminal electrode 6, seal fixing by glass seal layer 8,9.Modulate as glass seal layer 8,9 general mixing pyrex and metal dust, the paper material clamping resistive element 7 making this modulate, after in the axis hole 4 being injected into insulating part 2, pressing from pusher under the state stating terminal electrode 6, firing in baking furnace and solidifying.And now, also can fire glaze layer on the surface of the rear end side main part 10 of insulating part 2 simultaneously, also can form glaze layer in advance.
Afterwards, the insulating part 2 with the central electrode 5 as above manufactured respectively and terminal electrode 6 is fixed with the main metal fixture 3 with grounding electrode 27.Specifically, inserting to main metal fixture 3 on the basis of insulating part 2, the peristome of the rear end side of the main metal fixture 3 formed compared with unfertile land is being riveted to radially inner side, namely by forming above-mentioned caulking part 20, thus fixed insulation part 2 and main metal fixture 3.
Then, in bending operation, grounding electrode 27 is turned back to central electrode 5 curving, grounding electrode 27 is formed bend 27C.Afterwards in recess formation process, as shown in Fig. 7 (a), (b), the outer peripheral face of roll fixture JG1, the JG2 rotatably kept is made to abut side 27s1,27s2 of grounding electrode 27 respectively, while sandwiching grounding electrode 27 by two fixtures JG1, JG2 on this basis, make two fixtures JG1, JG2 along the long side direction synchronizing moving of grounding electrode 27.So, grounding electrode 27 plastic deformation, two sides 27s1,27s2 form recess 29.Afterwards, be formed in the processing of the size of the spark-discharge gap 28 between central electrode 5 and grounding electrode 27 by implementing adjustment, thus obtain above-mentioned spark plug 1.
In addition, when the long side direction along grounding electrode 27 forms recess discontinuously, the decompressor (not shown) also by regulation makes grounding electrode 27 be out of shape, thus forms recess.Further, grounding electrode 27 be attached to main metal fixture 3 in conjunction with operation before, also can form recess (namely also can carry out recess formation process before in conjunction with operation) on grounding electrode 27.Therefore, after recess can being defined to directly bar-shaped grounding electrode 27, this grounding electrode 27 is combined with main metal fixture 3.Further, after also flexible grounding electrode 27, form recess, afterwards in main metal fixture 3 in conjunction with grounding electrode 27.
As mentioned above, according to the present embodiment, in bend 27C, the back side 27b of grounding electrode 27 or side 27s1,27s2 at least partially on the recess 29 that the long side direction along grounding electrode 27 extends is set, the hardness of the bottom 29b of recess 29 is greater than the above-mentioned middle body of grounding electrode 27 (position of firmness change does not occur the formation along with recess 29 substantially).Therefore, can effectively improve the intensity that stress is especially easy to concentrated bend 29C in pole, the resistance to property lost of grounding electrode 27 can be improved tremendously.In addition, the present invention is as shown in the embodiment, especially effective when using thinner, that the resistance to property lost may reduce grounding electrode 27.
Further, recess 29 is formed in the whole region of the long side direction of bend 27C, therefore can improve intensity in the whole region of bend 27C, improve the resistance to property lost.
And, if the degree of depth of 20 recesses is D (mm), grounding electrode 27 along the thickness of the depth direction of recess 29 be TD (mm), recess 29 wide for W (mm) and grounding electrode 27 be TW (mm) along the thickness of the Width of recess 29 time, meet 0 < D≤TD/2 and TW/20≤W < TW ground and form.Therefore, while can fully maintaining the thickness of grounding electrode 27, conscientiously improve the hardness of bottom 29b further.Result can further improve the resistance to property lost.
Further, form recess 29 at two sides 27s1,27s2 of grounding electrode 27, therefore become the form that grounding electrode 27 is clamped by two recesses 29, the bottom 29b hardness of recess 29 can be increased.
Further, when forming recess 29 before bending grounding electrode 27, when bending grounding electrode 27, the hardness of bottom 29b may decline, and therefore in the present embodiment, forms recess 29 ground and form after having bent grounding electrode 27.Therefore, can prevent hardness from declining more effectively, improve the resistance to property lost further.
Further, as formed recess 29 before grounding electrode 27 combines, be then easy to form recess 29.Further, as made the cross sectional shape of recess be bending (with reference to Fig. 6 (b)), then can suppress the loss of the fixture used when forming recess, improve productivity.
Then, in order to confirm the action effect that above-mentioned execution mode produces, manufacture following sample, the resistance to property lost evaluation experimental is carried out to each sample: make the outer surface flat condition of grounding electrode form the sample (sample A) of the spark plug of (namely recess not being set); The sample (sample B, sample A, B are all equivalent to comparative example) of the spark plug of the recess that arranges by implementing cut to two sides of grounding electrode (even if the hardness being positioned at the middle body in the face of central electrode side in the bottom of recess and grounding electrode is same degree); By implementing plastic working to the back side of grounding electrode or side and arrange recess, the hardness of concave bottom is made to be greater than the sample (being equivalent to embodiment) of the spark plug of the hardness of the above-mentioned middle body of grounding electrode.The summary of the resistance to property lost evaluation test is as follows.That is, each sample is assembled in the two-wheel vehicle used single cylinder motor (air displacement 125cc) of larger vibration, drives above-mentioned engine.And, grounding electrode is observed every the stipulated time, be measured to the time (endurance) required till cracking in grounding electrode, and calculate the ratio (durability increase rate) of endurance relative to the endurance of the sample A suitable with comparative example of each sample.And, for the sample being provided with recess, recess is measured (when two sides of grounding electrode arrange recess by the Vickers of regulation, any one recess) bottom hardness, and calculate the ratio (hardness climbing) of above-mentioned bottom hardness relative to the hardness of the above-mentioned middle body of grounding electrode.
Table 1 represents durability increase rate in each sample and hardness climbing.In addition, for the sample being equivalent to embodiment, change the forming surface (recess forming surface) of the recess in grounding electrode respectively, forming range along the recess of the long side direction of grounding electrode (arranges recess in the roughly whole region of the long side direction of grounding electrode, still only corresponding bend is arranged, or only a part for bend is arranged), recess (is arranged on the Width central authorities of recess forming surface by the forming position along the recess of the Width of the recess in recess forming surface, or depart from setting from central authorities), shape (the cross sectional shape of recess, and along the shape (continuously or be interrupted) of long side direction), and the degree of depth D of recess, width W.Table 1 represents the forming position (recess forming position) of the recess on the forming range (recess forming range) of the recess forming surface in each sample, the recess in long side direction, Width, the shape of recess and degree of depth D, the width W of recess simultaneously.In addition, in each sample all: grounding electrode is 1.3mm along the thickness TD in recess depths direction, grounding electrode is 2.7mm along the thickness TW of the Width of recess.Further, for sample 23, recess being set by implementing plastic working to the grounding electrode of directly bar-shaped (bending before), for other samples, after grounding electrode defines bend, recess being set by implementing plastic working.
(table 1)
As shown in table 1, the known side at grounding electrode, the back side arrange recess and make the bottom hardness of recess be greater than the sample (sample 1 ~ 29) of the hardness of the above-mentioned middle body of grounding electrode, have the good resistance to property lost respectively.This is because, by increasing the hardness of bottom, improve the intensity of bend.
And confirm: the sample (sample 2 ~ 10,12 ~ 29) that the degree of depth D of recess and width W meet 0 < D≤TD/2 and TW/20≤W < TW relative to TD, TW of grounding electrode has the good resistance to property lost further.Specify that further: in these samples, the durability increase rate meeting the sample (sample 4 ~ 7) of TD/6≤D≤TD/3 and TW/6≤W < TW/3 is 2.5, has the fabulous resistance to property lost.This is because by making the degree of depth D of recess, width W be in above-mentioned number range, the hardness of bottom increases further.
Further, comparative sample 3 and 12, sample 15 and 16 etc. are known, and the sample that a side of sample and grounding electrode that two sides of grounding electrode are provided with recess is provided with recess is compared, and has the resistance to property lost preferably.
Further, compare and form time of recess different sample 3 and 23, the bottom hardness arranging the sample 3 of recess after known bending grounding electrode increases, and the resistance to property lost is good.This is because when arranging recess before grounding electrode is bending, along with bending of grounding electrode, bottom hardness declines, and by forming recess after grounding electrode is bending, can prevent hardness from declining.
Further, although confirm as at least formed recess in a part for bend, then can fully improve the resistance to property lost, known, by arranging recess in the whole region of the long side direction of bend, performance good further can be realized from the angle of the resistance to property lost.And known, even if the cross sectional shape of the shape of the long side direction along recess (continuously, being interrupted), recess is different respectively, also can fully improve the resistance to property lost.
Known by above result of the test, for improving the resistance to property lost in grounding electrode, in preferred bend the back side of grounding electrode and two sides at least partially on form the recess that the long side direction to grounding electrode extends, and make the hardness of concave bottom be greater than the hardness of the above-mentioned middle body of grounding electrode.
And, from the angle improving the resistance to property lost further, preferably meet 0 < D≤TD/2 and TW/20≤W < TW ground and form recess, or recess is set in two sides of grounding electrode, or recess is formed after bend is formed, form recess with preferably meeting TD/6≤D≤TD/3 and TW/6≤W≤TW/3 further.
Further, be not limited to the contents of above-mentioned execution mode, such as, also can implement as follows.Certainly following not illustrated other application examples, modification can also be used.
A () in the above-described embodiment, spark-discharge gap 28 is formed between central electrode 5 and grounding electrode 27, but also can the noble metal chip be made up of precious metal alloys (such as platinum alloy, iridium alloy etc.) be set at least one of two electrodes 5,27, between two noble metal chips being set between the noble metal chip of an electrode and another electrode or be arranged on two electrodes, form spark-discharge gap.
B () in the above-described embodiment, the situation that grounding electrode 27 is combined with the leading section 26 of main metal fixture 3 is specialized, is also applicable to following situation: the part of cutter body accessory (or being welded to the part of front end accessory for main metal fixture in advance) and form grounding electrode (such as JP 2006-236906 publication etc.).
C () in the above-described embodiment, tool engagement portion 19 is cross section hexagonal configurations, but the shape of tool engagement portion 19 is not limited to this shape.Such as may also be Bi-HEX (being out of shape 12 jiaos) shape (ISO22977:2005 (E)) etc.
Claims (6)
1. a spark plug, has:
The insulator of tubular, has at the through axis hole of axis direction;
Central electrode, inserts the side, front end being set to above-mentioned axis hole;
The main metal fixture of tubular, is arranged on the periphery of above-mentioned insulator; And
Grounding electrode, is configured in the leading section of aforementioned body accessory,
Above-mentioned grounding electrode passes through the bend of self to above-mentioned central electrode curving,
The feature of above-mentioned spark plug is:
In above-mentioned bend, being positioned at and the going up at least partially of the back side of the above-mentioned grounding electrode of above-mentioned central electrode opposite side and two sides adjoining with this back side, be formed in the recess that the long side direction of above-mentioned grounding electrode extends,
In the cross section of the orthogonality of center shaft with above-mentioned grounding electrode, in above-mentioned grounding electrode, the hardness of the bottom of above-mentioned recess is greater than in above-mentioned grounding electrode the hardness of the middle body in the face being positioned at above-mentioned central electrode side.
2. spark plug according to claim 1, is characterized in that, above-mentioned recess is formed in the whole region of the long side direction of above-mentioned bend.
3. spark plug according to claim 1 and 2, is characterized in that, in the cross section orthogonal with the long side direction of above-mentioned grounding electrode,
If the degree of depth of above-mentioned recess is Dmm, above-mentioned grounding electrode along the thickness of the depth direction of above-mentioned recess be TDmm, above-mentioned recess wide for Wmm, above-mentioned grounding electrode be TWmm along the thickness of the Width of above-mentioned recess time, meet following formula (1) and (2):
0<D≤TD/2……(1)
TW/20≤W<TW……(2)
。
4. spark plug according to claim 3, is characterized in that, meets following formula (3) and (4):
TD/6≤D≤TD/3……(3)
TW/6≤W≤TW/3……(4)
。
5. the spark plug according to any one in claim 1,2,4, is characterized in that, above-mentioned recess is respectively formed at above-mentioned two sides of above-mentioned grounding electrode.
6. a manufacture method for spark plug, is the manufacture method of the spark plug described in any one of claim 1 to 5, it is characterized in that, comprising: bending operation, above-mentioned grounding electrode forms above-mentioned bend; And recess formation process, above-mentioned grounding electrode forms recess,
After above-mentioned bending operation, carry out above-mentioned recess formation process.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2011019396A JP5255661B2 (en) | 2011-02-01 | 2011-02-01 | Spark plug and manufacturing method thereof |
| JP2011-019396 | 2011-02-01 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN102629734A CN102629734A (en) | 2012-08-08 |
| CN102629734B true CN102629734B (en) | 2014-12-17 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201210022312.3A Active CN102629734B (en) | 2011-02-01 | 2012-02-01 | Spark plug and manufacture method thereof |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JP5255661B2 (en) |
| CN (1) | CN102629734B (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5990216B2 (en) | 2014-05-21 | 2016-09-07 | 日本特殊陶業株式会社 | Spark plug |
| US10615576B1 (en) * | 2019-04-02 | 2020-04-07 | Caterpillar Inc. | Spark plug |
| JP7316252B2 (en) * | 2020-07-17 | 2023-07-27 | 日本特殊陶業株式会社 | Spark plug |
| US11670915B2 (en) | 2020-11-12 | 2023-06-06 | Federal-Mogul Ignition Gmbh | Composite sparking component for a spark plug and method of making the same |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5007389A (en) * | 1987-12-17 | 1991-04-16 | Ryohei Kashiwara | Ignition plug for internal combustion engines and a process for igniting gas mixture by the use thereof |
| CN2186459Y (en) * | 1993-12-22 | 1994-12-28 | 宁波金欧厨具有限公司 | Improved structure of sparking plug terrestrial pole |
| US5998912A (en) * | 1996-01-16 | 1999-12-07 | Schwab; Joseph P. | Spark plug |
| CN101772870A (en) * | 2007-07-31 | 2010-07-07 | 株式会社电装 | Spark plug for internal combustion engine and method of producing the same |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH01264187A (en) * | 1988-04-12 | 1989-10-20 | Ryohei Kashiwabara | Rapid burning device for ignition cap |
| JPH03208281A (en) * | 1990-01-08 | 1991-09-11 | Ngk Spark Plug Co Ltd | Spark plug of internal combustion engine |
| JP4070228B2 (en) * | 2000-03-09 | 2008-04-02 | 日本特殊陶業株式会社 | Manufacturing method of spark plug |
| JP5245578B2 (en) * | 2007-07-31 | 2013-07-24 | 株式会社デンソー | Spark plug for internal combustion engine |
-
2011
- 2011-02-01 JP JP2011019396A patent/JP5255661B2/en not_active Expired - Fee Related
-
2012
- 2012-02-01 CN CN201210022312.3A patent/CN102629734B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5007389A (en) * | 1987-12-17 | 1991-04-16 | Ryohei Kashiwara | Ignition plug for internal combustion engines and a process for igniting gas mixture by the use thereof |
| CN2186459Y (en) * | 1993-12-22 | 1994-12-28 | 宁波金欧厨具有限公司 | Improved structure of sparking plug terrestrial pole |
| US5998912A (en) * | 1996-01-16 | 1999-12-07 | Schwab; Joseph P. | Spark plug |
| CN101772870A (en) * | 2007-07-31 | 2010-07-07 | 株式会社电装 | Spark plug for internal combustion engine and method of producing the same |
Also Published As
| Publication number | Publication date |
|---|---|
| CN102629734A (en) | 2012-08-08 |
| JP5255661B2 (en) | 2013-08-07 |
| JP2012160351A (en) | 2012-08-23 |
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