CN104143766B - Spark plug - Google Patents
Spark plug Download PDFInfo
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- CN104143766B CN104143766B CN201410191258.4A CN201410191258A CN104143766B CN 104143766 B CN104143766 B CN 104143766B CN 201410191258 A CN201410191258 A CN 201410191258A CN 104143766 B CN104143766 B CN 104143766B
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- nickel dam
- mentioned
- terminal electrode
- spark plug
- rearward end
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01T—SPARK GAPS; OVERVOLTAGE ARRESTERS USING SPARK GAPS; SPARKING PLUGS; CORONA DEVICES; GENERATING IONS TO BE INTRODUCED INTO NON-ENCLOSED GASES
- H01T13/00—Sparking plugs
- H01T13/02—Details
- H01T13/04—Means providing electrical connection to sparking plugs
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Abstract
The present invention provides a kind of spark plug, and it is provided with recess in the rearward end of terminal electrode, and is formed with nickel dam, in this spark plug in the rearward end of terminal electrode, it will improves the corrosion resistance of terminal electrode fully, and suppresses the stripping of nickel dam more reliably.Spark plug (1) including: insulation electroceramics (2), it has the axis hole (4) run through along axis (CL1) direction；And terminal electrode (6), its state exposed with the rear end of the self-insulating electroceramics of the rearward end (2) of self is inserted in axis hole (4).Rearward end at terminal electrode (6) arranges the recess (6B) with axis CL1 direction as depth direction.The outer surface of the rearward end of terminal electrode (6) arranges nickel dam (35).The thickness of nickel dam (35) is 3 μm～25 μm, and in the cross section orthogonal with the outer surface of nickel dam (35), the average cross-section of the crystal grain constituting nickel dam (35) is 50 μm2～500 μm2。
Description
Technical field
The present invention relates to a kind of spark plug being used in internal combustion engine etc..
Background technology
Spark plug is installed on internal combustion engine (electromotor) etc., for lighting a fire the mixed gas in combustor etc..
In general, spark plug includes: insulator, and it has the axis hole extended in the axial direction；Central electrode,
It inserts the tip side arranging this axis hole；Terminal electrode, it inserts the rear end side arranging axis hole；Main
Body metal shell, it is located at the periphery of insulator；And ground electrode, it is fixed on base metal shell
Top ends.Additionally, the rear end of the self-insulating body of the rearward end of terminal electrode self is exposed, and in this rear end
Portion connects the terminal of power supply.In addition, the rearward end autonomous agent metal shell of insulator self
Rear end expose, and this insulator be positioned at the rearward end of terminal electrode and base metal shell rear end it
Between.
Additionally, in recent years, in order to be more reliably prevented from along rearward end and the main body gold being positioned at terminal electrode
The electric discharge on the surface of the insulator between the rear end of genus shell, it is known to by by autonomous agent metal shell
The distance of rear end to the rear end of terminal electrode remain constant while further after lengthened insulative body
End thus guarantee that the rear end of autonomous agent metal shell is to the distance of the rearward end of terminal electrode significantly
Method (for example, referring to patent documentation 1 etc.).Further it is proposed to the rearward end of terminal electrode arrange with
Axis direction is the technology (for example, referring to patent documentation 2 etc.) of the recess of depth direction.
In addition, in order to realize the raising of the corrosion resistance in terminal electrode, sometimes at terminal electrode
At least rearward end forms the nickel dam being made up of the metal with nickel as main component (for example, referring to patent documentation
3 etc.).It addition, when forming nickel dam, generally terminal electrode is carried out electroplating processes by electroplanting device.
Prior art literature
Patent documentation
Patent documentation 1:WO2011/33902 publication
Patent documentation 2: Japanese Unexamined Patent Publication 2012-128948 publication
Patent documentation 3: Japanese Unexamined Patent Publication 2005-285468 publication
But, as described above in the case of terminal electrode is provided with recess, the thickness of nickel dam easily becomes
Obtain uneven, be easily caused the stripping of the reduction of corrosion resistance, nickel dam.Specifically, for recess
For bottom surface, owing to electric field intensity is relatively low, therefore there is nickel dam the most thinning, corrosion resistance is not filled
The hidden danger divided.On the other hand, for the position of the periphery being positioned at recess in terminal electrode, due to
Electric field intensity becomes higher relatively, therefore has that nickel dam is the most thickening, heat between nickel dam and terminal electrode
Differential expansion becomes the peel resistance fall in big (thermal stress in other words, putting on nickel dam becomes big), nickel dam
Low hidden danger.
Summary of the invention
The present invention completes in view of the foregoing, it is intended that be the rearward end of terminal electrode
Recess it is set and is formed in the spark plug of nickel dam at the rearward end outer surface of terminal electrode, improving fully
The corrosion resistance of terminal electrode and suppress the stripping of nickel dam more reliably.
Hereinafter, to be applicable to solve above-mentioned purpose each structure subitem illustrate.It addition, it is the most right
Corresponding structure records distinctive action effect.
The spark plug of 1. structures of structure is characterised by, this spark plug includes: insulator, and it has
The axis hole run through in the axial direction；And
Terminal electrode, it is inserted into from the state that the rear end of above-mentioned insulator is exposed with the rearward end of self
State in axis hole；
Rearward end at above-mentioned terminal electrode is provided with the recess with above-mentioned axis direction as depth direction,
The outer surface of the rearward end of above-mentioned terminal electrode is provided with nickel dam,
The thickness of above-mentioned nickel dam is 3 μm～25 μm, and,
In the cross section orthogonal with the outer surface of above-mentioned nickel dam, constitute the averga cross section of the crystal grain of above-mentioned nickel dam
Amassing is 50 μm2～500 μm2。
According to said structure 1, owing to the thickness of nickel dam is below 25 μm, therefore, it is possible to relatively reduced
The thermal expansion difference produced between nickel dam and terminal electrode.Thus, it is possible to the relatively reduced heat putting on nickel dam
Stress such that it is able to improve the peel resistance of nickel dam.
And, according to said structure 1, the average cross-section of the crystal grain constituting nickel dam is 50 μm2Above,
Crystal grain is inhibited to become over tiny.Make a concerted effort therefore, it is possible to improve Grain-boundary Junctions fully, executed at nickel dam
When having added thermal stress, it is possible to be more reliably prevented from cracking at crystal boundary.It addition, according to said structure 1,
The average cross-section of crystal grain is 500 μm2Hereinafter, the particle diameter of crystal grain is relatively small.Thus, in nickel dam,
The endurance to thermal stress resistance can be improved fully.These action effects and the above-mentioned thickness making nickel dam become
The action effect brought time below 25 μm interacts, it is possible to be more reliably prevented from the stripping of nickel dam.
It addition, according to said structure 1, the thickness of nickel dam is more than 3 μm.Thus, it is possible to subtract fully
The pinhole number in each per surface area in few nickel dam such that it is able to suppression more reliably becomes corrosion
The contact to terminal electrode such as reason, oxygen.
And, according to said structure 1, owing to making the average cross-section of crystal grain become 50 μm2Above, because of
This is difficult to crack at crystal boundary, connects terminal electrode therefore, it is possible to be reliably suppressed oxygen etc. further
Touch.And, although nickel dam is formed in the way of crystalline phase stacking, but according to said structure 1, crystal grain
Average cross-section is 500 μm2Hereinafter, the particle diameter of crystal grain is relatively small.Thus, it is possible to reduce further
Crystal boundary concavo-convex such that it is able to the local being more reliably prevented from crystallizing layer is thinning.These action effects and upper
State the action effect making the thickness of nickel dam be brought when becoming more than 3 μm to interact, it is possible to realize good
Good corrosion resistance.
As described above, according to said structure 1, it is possible to improve peel resistance and corrosion resistance fully
Both.As a result, even if being that the rearward end of terminal electrode forms recess and more worries in terminal electrode
The reduction of corrosion resistance, nickel dam stripping in the case of, it is also possible to optimize peel resistance and corrosion resistance
Both.
The spark plug of 2. structures of structure is, according to the spark plug described in said structure 1, it is characterised in that
The thickness of above-mentioned nickel dam is 10 μm～20 μm, and,
In above-mentioned cross section, the average cross-section of above-mentioned crystal grain is 200 μm2～400 μm2。
According to said structure 2, owing to the thickness of nickel dam is below 20 μm, therefore, it is possible to reduce further
Put on the thermal stress of nickel dam.Further, it is 200 μm due to the average cross-section of crystal grain2Above, therefore
Grain-boundary Junctions can be improved further make a concerted effort such that it is able to be reliably prevented further and crack at crystal boundary.
Further, since the average cross-section of crystal grain is 400 μm2Hereinafter, therefore, it is possible to improve nickel dam further
Endurance to thermal stress resistance.Above as a result, it is possible to improve the peel resistance of nickel dam further.
And, according to said structure 2, owing to the thickness of nickel dam is more than 10 μm, therefore, it is possible to enter one
Step reduces the pinhole number in each per surface area in nickel dam.It is additionally, since the averga cross section making crystal grain
Amass and become 200 μm2Above, therefore, it is possible to suppress the generation of the crackle of grain boundaries further, it addition, by
Average cross-section in crystal grain is 400 μm2Hereinafter, therefore, it is possible to be reliably prevented crystallizing layer further
The most thinning.Above as a result, it is possible to increase substantially corrosion resistance.
As described above, according to said structure 2, it is possible to significantly improve peel resistance and corrosion resistance this
Both.As a result, even if in the case of being that the rearward end of terminal electrode is formed with recess, it is also possible to realize
The most excellent peel resistance and corrosion resistance.
The spark plug of 3. structures of structure is, according to the spark plug described in said structure 1 or 2, and its feature
Being, the thickness of the oxide-film on the outer surface of above-mentioned nickel dam is below 1.0 μm.
According to said structure 3, the thickness of the oxide-film on the outer surface of nickel dam is below 1.0 μm.Thus,
The flexibility of nickel dam can be guaranteed fully such that it is able to improve in nickel dam thermal stress resistance further
Endurance.As a result, it is possible to realize better peel resistance.It addition, in the aspect of peel resistance, oxidation
Film is the thinnest more preferred.
The spark plug of 4. structures of structure is, according to the spark plug according to any one of said structure 1 to 3,
It is characterized in that, the hardness at the rearward end of above-mentioned terminal electrode is Vickers hardness 140Hv～180Hv.
According to said structure 4, the hardness of the rearward end of terminal electrode is 140Hv～180Hv.Thus, it is possible to enter
One step reduces the thermal expansion difference between terminal electrode and nickel dam such that it is able to is obviously reduced and puts on nickel dam
Thermal stress.As a result, it is possible to increase substantially peel resistance.
The spark plug of 5. structures of structure is, according to the spark plug according to any one of said structure 1 to 4,
It is characterized in that, above-mentioned terminal electrode possesses the ring-type outside wall portions of the surrounding surrounding above-mentioned recess, above-mentioned
The recess at least inner peripheral surface by above-mentioned outside wall portions and the bottom surface as the plane orthogonal with above-mentioned axis direction
Formed, and, in the inner peripheral surface of above-mentioned outside wall portions, at least than the half on above-mentioned axis direction rearward
The thickness of the above-mentioned nickel dam at the position of side is more than the thickness of the nickel dam at above-mentioned bottom surface.Electric power is being supplied
To terminal arrangement when the recess, the half on ratio axis direction in the inner peripheral surface of outside wall portions is held rearward
The effect of the guiding of the terminal for properly configuring power supply in recess is played at the position of side.This
Time, due to the terminal of power supply, to wipe the inner peripheral surface rubbed in outside wall portions directed, therefore deposits
In the hidden danger that nickel dam is shaved.According to said structure 5, due in the inner peripheral surface of above-mentioned outside wall portions, extremely
The thickness of the above-mentioned nickel dam at few position than the side rearward of the half on above-mentioned axis direction is relatively big, therefore
It also is able to suppress terminal electrode mother metal to expose even if nickel dam is shaved.
Accompanying drawing explanation
Fig. 1 is the biopsy cavity marker devices front view of the structure representing spark plug.
Fig. 2 is the amplification stereogram of the structure of the rearward end representing terminal electrode.
Fig. 3 is the sectional view of terminal electrode etc..
(a), (b) of Fig. 4 is the explanatory diagram of the computational methods of the average cross-section for crystal grain is described.
Fig. 5 is the amplification schematic cross-section of the oxide-film etc. representing the outer surface being formed at nickel dam.
Fig. 6 is for cuing open the amplification measuring the terminal electrode that position illustrates of the hardness of terminal electrode
View.
Fig. 7 is the terminal electrode for illustrating the relation of the thickness of the nickel dam being formed at terminal electrode
Amplification view.
Description of reference numerals
1 ... spark plug；2 ... insulation electroceramics (insulator)；4 ... axis hole；6 ... terminal electrode；6A ... outer
Wall portion；6B ... recess；6C ... bottom surface；6D ... inner peripheral surface；35 ... nickel dam；36 ... oxide-film；
CL1 ... axis.
Detailed description of the invention
Hereinafter, with reference to the accompanying drawings of an embodiment.Fig. 1 is the biopsy cavity marker devices front view representing spark plug 1.
It addition, in FIG, the axis CL1 direction of spark plug 1 is set to the above-below direction of accompanying drawing, downside is set
For the tip side of spark plug 1, upside is set to rear end side and illustrates.
Spark plug 1 is by being formed as the insulation electroceramics 2 as insulator of tubular and keeping this insulation electroceramics 2
Base metal shell 3 grade of tubular is constituted.
Insulation electroceramics 2 is formed by sintered alumina etc. as well-known, includes in its profile portion:
Rear end side main part 10, it is formed at rear end side；Large-diameter portion 11, it is than this rear end side main part 10
By tip side position to radial outside prominent formed；Intermediate body portions 12, it is than this large-diameter portion 11
Position by tip side is formed with the diameter thinner than this large-diameter portion 11；And foot 13, it is in the middle of than this
Main part 12 is formed with the diameter thinner than this intermediate body portions 12 by the position of tip side.Additionally, insulated electro
Large-diameter portion 11, intermediate body portions 12 and most foot 13 in porcelain 2 are contained in base metal shell
The inside of 3, and the rear end of rear end side main part 10 autonomous agent metal shell 3 exposes.And, centre master
Connecting portion between body 12 and foot 13 is formed with the stage portion 14 of taper, utilizes this stage portion 14 to incite somebody to action
Insulation electroceramics 2 is engaging in base metal shell 3.
And, insulation electroceramics 2 is formed through the axis hole 4 extended along axis CL1, at this axis hole 4
Tip side be inserted with central electrode 5.This central electrode 5 includes internal layer 5A and outer layer 5B, and this is interior
Layer 5A is made up of the metal (such as copper, copper alloy etc.) of excellent thermal conductivity, and this outer layer 5B is by with nickel (Ni)
Alloy for main component is constituted.And, the top ends at central electrode 5 is provided with by resistance to expendable excellent
Metal (such as, the metal containing more than one in Pt, Ir, Pd, Rh, Ru and Re etc.
Deng) the columned electrode tip 31 that constitutes.It addition, central electrode 5 is integrally formed into bar-shaped (cylindric),
And the top of self-insulating electroceramics 2 highlights.
In addition, the rear end side at axis hole 4 is provided with by predetermined metal (such as, mild steel etc.) structure
The bar-shaped terminal electrode 6 become.The rear end of the self-insulating electroceramics of rearward end 2 of terminal electrode 6 is exposed, at end
The rearward end of sub-electrode 6 connects the terminal (not shown) of power supply.
And, between the central electrode 5 and terminal electrode 6 of axis hole 4, it is configured with columned resistive element 7.
The both ends of this resistive element 7 are electric with central electrode 5 and terminal respectively across the glass seal layer 8,9 of electric conductivity
Pole 6 is electrically connected.
In addition, aforementioned body metal shell 3 is formed as tubular by metals such as mild steel, and outside it
Side face is formed with threaded portion (external thread part) 15, this threaded portion 15 for spark plug 1 is installed on internal combustion engine,
The installing hole of fuel cell modification device etc..It addition, formed oriented than the position of side rearward, threaded portion 15
The seat portion 16 that radial outside is prominent, the screw neck 17 in rear end, threaded portion 15 is embedded with ring-type packing ring 18.
And, the rear end side at base metal shell 3 is provided with the tool engagement portion 19 of cross section hexagon shape, this work
Tool holding section 19 is for blocking mutually with the instrument such as spanner when base metal shell 3 is installed on internal combustion engine etc.
Close, and be provided with the fastening part 20 for the electroceramics 2 that keeps insulating in the rearward end of base metal shell 3.
It addition, be provided with the step of the taper for locking insulation electroceramics 2 at the inner peripheral surface of base metal shell 3
Portion 21.Further, insulation electroceramics 2 relative to base metal shell 3 from its rear end lateral tip side insert,
Under the state that self stage portion 14 is mutually locking with the stage portion 21 of base metal shell 3, make base metal
The peristome of the rear end side of shell 3 fastens to radially inner side, i.e. forms above-mentioned fastening part 20, thus fixing
In base metal shell 3.It addition, be folded with circular liner plate 22 between above-mentioned stage portion 14,21.
Thus, the air-tightness in combustor is kept, it is to avoid enter the foot of the insulation electroceramics 2 being exposed in combustor
The gaseous fuel in the gap between the inner peripheral surface of portion 13 and base metal shell 3 is to External leakage.
And, airtight more complete, in the rear end side of base metal shell 3 in order to make under fastening effect
, base metal shell 3 and insulation electroceramics 2 between be folded with ring-type ring element 23,24, at ring structure
The powder of Talcum (talc) 25 it is filled with between part 23,24.That is, base metal shell 3 passes through liner plate
22, ring element 23,24 and Talcum 25 keep insulation electroceramics 2.
It addition, the top ends 26 at base metal shell 3 is fixed with in bar-shaped ground electrode 27.Ground connection
Electrode 27 is formed by the alloy etc. with Ni as main component, and is rolled at the substantial mid-portion of self
Return.In addition, (such as, the top ends at ground electrode 27 is provided with the metal by resistance to expendable excellence
Metal etc. containing more than one in Pt, Ir, Pd, Rh, Ru and Re etc.) cylinder that constitutes
The electrode tip 32 of shape.And, at the top ends (electrode tip 31) of central electrode 5 and ground electrode 27
Spark-discharge gap 33 is formed between top ends (electrode tip 32), in this spark-discharge gap 33,
Direction approximately along axis CL1 produces spark discharge.
And, in the present embodiment, in order to suppress the electric discharge (institute on the surface along rear end side main part 10
Meaning arcing) generation, the length along axis CL1 making rear end side main part 10 is bigger.The opposing party
Face, the distance of rear end to the rear end of terminal electrode 6 in order to make autonomous agent metal shell 3 be predetermined value with
In, make terminal electrode 6 rearward end (position that the rear end of self-insulating electroceramics 2 is exposed) along axis CL1
Length relatively small.It addition, as shown in Fig. 2 (the most only illustrating the rearward end of terminal electrode 6),
The ring-type outside wall portions extended to axis CL1 direction rear end side it is provided with in the rearward end periphery of terminal electrode 6
6A, utilizing outside wall portions 6A to be centrally formed in the rearward end of terminal electrode 6 with axis CL1 direction is degree of depth side
To recess 6B.So, the rearward end at terminal electrode 6 is provided with in the way of surrounding around recess 6B
Ring-type outside wall portions 6A.And, the terminal (not shown) of power supply is configured at recess 6B.
It addition, as it is shown on figure 3, the outer surface of the rearward end of terminal electrode 6 be provided with by with Ni for main become
The nickel dam 35 that the metal divided is constituted is (it addition, " main component " refers to the one-tenth that mass ratio in material is the highest
Point).Nickel dam 35 is configured to, although thickness T1 has some different at each several part, but this thickness T1 is 3
μm～25 μm.In addition, on the cross section orthogonal with the outer surface of nickel dam 35, composition nickel dam is made
The average cross-section of the crystal grain of 35 is 50 μm2～500 μm2(more preferably 200 μm2～400 μ
m2).It addition, in the present embodiment, the average perimeter of above-mentioned crystal grain be 60 μm～200 μm (more
Preferably 80 μm～150 μm).It addition, in the inner peripheral surface 6D of outside wall portions 6A, be located at least in
It is more than at the 6C of bottom surface than the thickness of the nickel dam 35 at the position of the half side rearward on axis CL1 direction
The thickness of nickel dam 35.In the present embodiment, with the tip side from the inner peripheral surface of outside wall portions 6A backward
Side is gone and mode that thickness is gradually increased is formed with nickel dam 35.
It addition, the average cross-section of crystal grain, average perimeter can be obtained by following method.That is, logical
Cross predetermined focused ion bundle processing unit (plant) (FIB), cut along the direction orthogonal with the outer surface of nickel dam 35
Disconnected nickel dam 35, it is thus achieved that comprise the thin slice of nickel dam 35.Then, predetermined sweep electron microscope is utilized
(SIM) observe the thin slice obtained, and comprise nickel dam 35 with the multiplying power shooting of 6500 times
The scope of horizontal 30 μm of vertical 20 μ m, it is thus achieved that gray level image.Afterwards, if (a) of Fig. 4 is (at Fig. 4
In illustrate only a crystal grain 35A, but in actual gray level image, there is multiple crystal grain 35A) institute
Show, in above-mentioned gray level image, it is intended that be positioned at the lateral center of this image and be located along longitudinal extension
The crystal grain 35A of the nickel dam 35 on line, and, the trim line of the crystal grain 35A specified is transferred to predetermined
On thin paper.Then, predetermined computer obtains the data of above-mentioned thin paper, uses predetermined figure afterwards
As software (such as, paint), as shown in (b) of Fig. 4, fill the inner side being positioned at above-mentioned trim line
Region.Then, predetermined parsing software (such as, imageJ: US National health research is utilized
Made) measure the area in each region after filling, girth.Finally, the area gone out by computation and measurement
Meansigma methods, it is possible to obtain crystal grain average cross-section, by the meansigma methods of the girth that computation and measurement goes out,
It is obtained in that the average perimeter of crystal grain.It addition, as FIB, such as the focusing of society of Hitachi can be enumerated
Ion beam processing tool (model FB-2000, SIM " sweep electron microscope " is one-piece type) etc..
And, by nickel dam 35 is aoxidized, thus as shown in Figure 5 in the outer surface formation of nickel dam 35
Oxide-film 36.But, in the present embodiment, the wall thickness of oxide-film 36 is the thinnest, and its thickness T2 is
Below 1.0 μm.It addition, the face for the peel resistance of nickel dam 35 considers, the wall thickness of oxide-film 36 is more
Thin the most preferred, more preferably there is not oxide-film 36.But, in the present embodiment, due to rear
That states heats fire end sub-electrode 6 in sealing process and forms oxide-film 36 on the outer surface of nickel dam 35,
The thickness T2 of oxide-film 36 is more than 0.01 μm.
In addition, in the present embodiment, making the hardness at the rearward end of terminal electrode 6 is that Vickers is hard
Degree 140Hv～180Hv.It addition, the hardness at the rearward end of terminal electrode 6 can be surveyed by the following method
Amount.I.e., as shown in Figure 6, in the cross section comprising axis CL1, choose line segment SL, this line segment SL position
In leaving towards axis CL1 side from the periphery of terminal electrode 6 on the direction orthogonal with axis CL1
The position of 0.5mm, and extend along axis CL1 direction, and be present on terminal electrode 6.Then,
According to the regulation of JIS Z2244, utilize the diamond penetrator of positive corner taper to being positioned in terminal electrode 6
The position of the midpoint CP of above-mentioned line segment SL applies the load of predetermined (such as, 20kgf).Then, it is possible to
Hard at the rearward end of catercorner length measurement terminal electrode 6 based on the impression being formed at terminal electrode 6
Degree.
It follows that illustrate that the manufacture method of the spark plug 1 constituted as described above illustrates.First,
Previously fabricated base metal shell 3.That is, by columned metal material (such as, S17C, S25C
This iron type materials, stainless steel material) implement Cold Forging etc. and form through hole, manufacture general shape.
Afterwards, profile is adjusted by machining, it is thus achieved that base metal shell intermediate.
Then, the pen that resistance welding is made up of Ni alloy etc. on the top end face of base metal shell intermediate
The most bar-shaped ground electrode 27.Owing to producing so-called " turned-down edge " when carrying out this welding, therefore going
Except being formed screw thread by rolling at the predetermined position of base metal shell intermediate after " turned-down edge "
Portion 15.Thus, obtain being welded with the base metal shell 3 of ground electrode 27.
Then, by processing predetermined metal material (such as, mild steel), bar-shaped terminal electricity is obtained
Pole 6.On this basis, by tumble-plating process, terminal electrode 6 is implemented electroplating processes, at terminal electrode 6
Nickel dam 35 is formed on outer surface.When carrying out electroplating processes, Tumble-plating device as follows is used (not scheme
Show), this Tumble-plating device includes: electroplating bath, and its storage has predetermined concentration (such as, 250 ± 20g/
L) nickel sulfate (NiSO4), the Nickel dichloride. (NiCl of predetermined concentration (such as, 50 ± 10g/L)2)、
Boric acid (the H of predetermined concentration (such as, 40 ± 10g/L)3BO3) and comprise the acid of polishing material
The electroplating water solution of property (pH is about 4.0 ± 0.5)；And holding container, its wall by net, open
The plate etc. being provided with hole is formed, and is immersed in the liquid of above-mentioned electroplating water solution.Specifically, by end
Sub-electrode 6 is contained in above-mentioned holding container, is immersed in electroplating water solution by terminal electrode 6.Then,
After making electroplating water solution become predetermined temperature (such as, 55 ± 5 DEG C), utilize predetermined
Motor makes above-mentioned holding container rotate, and makes predetermined electric current density (such as, 0.13A/
dm2～1.33A/dm2) DC current flow into terminal electrode 6 predetermined conduction time (such as, 9
Second～1500 seconds).Thus, the region at the whole outer surface of terminal electrode 6 forms nickel dam 35.In this reality
Execute in mode, by conduction time during regulation electroplating processes, electric current density (A/dm2), make nickel dam
The thickness T1 of 35 becomes 3 μm～25 μm, and makes the average cross-section of the crystal grain of composition nickel dam 35 become
It is 50 μm2～500 μm2.It addition, by regulating conduction time, it is possible to change the thickness of nickel dam 35
T1, by regulation electric current density, it is possible to change the average cross-section of crystal grain.
In addition, independent of aforementioned body metal shell 3 ground forming insulation electroceramics 2.Such as, make
It is main body in order to aluminium oxide and the material powder that comprises binding agent etc. prepares shaping blank granules, use
It is compressing that this shaping blank granules carries out rubber, thus obtains the formed body of tubular.To obtain
Shaping after formed body is implemented attrition process and adjusted its shape, and sintering adjusts shape in sintering furnace
Body, thus obtain insulation electroceramics 2.
It addition, independent of aforementioned body metal shell 3, insulation electroceramics 2 ground manufacturing center electrode 5.That is,
Forging processing is implemented for the Ni alloy seeking to improve the copper alloy etc. of thermal diffusivity to being configured with at central part,
Thus make central electrode 5.It addition, electrode tip 31 is engaged in central electrode 5 by laser welding etc.
Top ends.
Then, in utilizing glass seal layer 8,9 that insulation electroceramics 2 sealing obtained as described above is fixed
Heart electrode 5, terminal electrode 6 and resistive element 7.As glass seal layer 8,9, it is common that by borosilicate
Acid glass mixes with metal dust and prepares, and is injected into absolutely across resistive element 7 by the raw material after this preparation
In the axis hole 4 of edge electroceramics 2, afterwards while utilizing terminal electrode 6 pressing from rear, in sintering furnace
Heat, thus seal fixed center electrode 5 etc..It addition, now, both can be at insulation electroceramics 2
Rear end side main part 10 surface sinter glaze layer simultaneously, it is also possible to be pre-formed glaze layer.It addition, in this reality
Execute in mode, by regulating heat time heating time, make the thickness T2 of oxide-film 36 become below 1.0 μm.
Afterwards, relative to base metal shell 3, after its rear end side opening inserts insulation electroceramics 2, edge
The rearward end of axis CL1 direction pressing base metal shell 3, makes above-mentioned rearward end be radially oriented interior lateral bending
Bent (that is, forming fastening part 20), thus insulation electroceramics 2 is fixed with base metal shell 3.
Then, after electrode tip 32 is engaged in by resistance welding etc. the top ends of ground electrode 27,
Make ground electrode 27 to central electrode 5 lateral bend.And, finally, it is formed at central electrode 5 by adjustment
The size of the spark-discharge gap 33 between (electrode tip 31) and ground electrode 27 (electrode tip 32),
Obtain above-mentioned spark plug 1.
As described in detail above, according to present embodiment, the thickness T1 of nickel dam 35 is made to become 3 μ
M～25 μm, and make the average cross-section of crystal grain become 50 μm2～500 μm2.Thus, it is possible to
Improve both peel resistance and corrosion resistance fully.As a result, even if after being terminal electrode 6
End forms the feelings of the stripping of the reduction of corrosion resistance in recess 6B more worry terminal electrode 6, nickel dam
Under condition, it is also possible to optimize both peel resistance and corrosion resistance.
And, become 10 μm～20 μm at the thickness T1 making nickel dam 35 and make the average of crystal grain cut
Area becomes 200 μm2～400μm2In the case of, it is possible to improve peel resistance and corrosion resistant further
Both erosion property.
It addition, in the present embodiment, the thickness T2 of oxide-film 36 is made to become below 1.0 μm.Thus,
The flexibility of nickel dam 35 can be guaranteed fully such that it is able to improve in nickel dam 35, to heat resistanceheat resistant further
The endurance of stress.As a result, it is possible to realize better peel resistance.
And, make the hardness of the rearward end of terminal electrode 6 become 140Hv～180Hv.Thus, it is possible to enter
One step reduces the thermal expansion difference between terminal electrode 6 and nickel dam 35 such that it is able to is obviously reduced and puts on nickel
The thermal stress of layer 35.As a result, it is possible to significantly improve peel resistance.
Then, in order to be identified through the action effect that above-mentioned embodiment is played, by reconciling at plating
Electric current density during reason, conduction time, make the thickness T1 (μm) in multiple nickel dam and crystal grain
Average cross-section (μm2) sample of different terminal electrode, and each sample is carried out resistance to stripping
Property evaluation test and corrosion resistance evaluation test.It addition, terminal electrode has recess in rearward end.
The summary of peel resistance evaluation test is the most following.That is, tube furnace is utilized each sample to be added with 1000 DEG C
Heat 8 minutes, is slowly cooled to room temperature afterwards.Then, by visual or predetermined magnifier confirmation it is
The no outer surface in the rearward end of terminal electrode creates the stripping (rupturing) of nickel dam.Here, for
The evaluation as " ☆ " with extremely excellent peel resistance made by the sample of the stripping not producing nickel dam.
Although it addition, for creating the stripping of nickel dam but the area at the position being peeling (stripping area)
Less than terminal electrode rearward end surface area 5% sample make as have excellence peel resistance
The evaluation of " ◎ ", although peeling off after area is terminal electrode for creating the stripping of nickel dam
The 5% of the surface area of end～the sample of 10% make commenting as the "○" with good peel resistance
Valency.On the other hand, for creating the stripping of nickel dam and peeling off the area rear end more than terminal electrode
The evaluation of the "×" poor as peel resistance made by the sample of the 10% of the surface area in portion.
It addition, the summary of corrosion resistance evaluation test is the most following.That is, each sample is placed on ejection saline
In the environment of 48 hours, be confirmed whether to create rust on the rearward end surface of terminal electrode.Here, it is right
In the evaluation making " ☆ " extremely excellent as corrosion resistance to the sample producing rust unconfirmed.And
And, although but little for creating the area (rust generation area) at the position that rust produces rust
In terminal electrode rearward end surface area 5% sample make " ◎ " as excellent corrosion resistance
Evaluation, although but producing, for creating rust rust, the table of rearward end that area is terminal electrode
The 5% of area～the sample of 30% make the evaluation as the "○" with good corrosion resistance.Another
Aspect, to rust produce area exceed terminal electrode rearward end surface area 30% sample make work
Evaluation for the poor "×" of corrosion resistance.
The result of peel resistance evaluation test is shown in Table 1, corrosion resistance evaluation test is shown in table 2
Result.
[table 1]
[table 2]
As shown in table 1, it is clear that make the thickness T1 of nickel dam become below 25 μm and make the flat of crystal grain
All sectional areas become 50 μm2～500μm2Sample there is good peel resistance.In view of this be because of
Ground effect is mutually strengthened for following (1)～(3).
(1) by making the thickness T1 of nickel dam become below 25 μm, along with heating cooling, at nickel
The thermal expansion difference produced between layer and terminal electrode becomes relatively small, and then, the heat putting on nickel dam should
Power becomes relatively small.
(2) average cross-section by making crystal grain becomes 50 μm2Above, it is suppressed that crystal grain becomes over
Tiny, further increase Grain-boundary Junctions and make a concerted effort as a result, when nickel dam is applied with thermal stress, crystal boundary is difficult
To crack.
(3) average cross-section by making crystal grain becomes 500 μm2Hereinafter, the particle diameter making crystal grain becomes
Relatively small, thus substantially increase endurance in nickel dam, to thermal stress resistance.
And, as shown in table 2, it is clear that by making the thickness T1 of nickel dam become more than 3 μm and make
The average cross-section of crystal grain becomes 50 μm2～500 μm2Sample there is good corrosion resistance.Consider
To this is because ensuing (4)～(6) mutually strengthen ground effect.
(4) by making the thickness T1 of nickel dam become more than 3 μm, in each per surface area in nickel dam
Pinhole number tail off, it is suppressed that saline is attached to terminal electrode.
(5) average cross-section by making crystal grain becomes 50 μm2Above, improve Grain-boundary Junctions and make a concerted effort,
Thus crystal boundary is difficult to crack, and then saline is inhibited to be attached to terminal electrode.
(6) although nickel dam is formed in the way of crystalline phase stacking, but by making the average cross-section of crystal grain
Become 500 μm2Hereinafter, the particle diameter making crystal grain becomes relatively small, it is possible to make the concavo-convex of crystal boundary become more
Little, it is possible to the local being more reliably prevented from crystallizing layer is thinning.
Additionally, particularly, learn and make the thickness T1 of nickel dam become 10 μm～20 μm and make crystal grain
Average cross-section become 200 μm2～400 μm2Sample peel resistance and corrosion resistance this two
Person is the most excellent.
According to above-mentioned two test as a result, it is possible to say in order to optimize peel resistance and corrosion resistance this two
Person, preferably makes the thickness T1 of nickel dam become 3 μm～25 μm, and makes the average cross-section of crystal grain
Become 50 μm2～500 μm2。
Furthermore it is possible to say the further raising in order to seek peel resistance and corrosion resistance, preferably
It is to make the thickness T1 of nickel dam become 10 μm～20 μm, and makes the average cross-section of crystal grain become 200
μm2～400 μm2。
It follows that for making the thickness T1 of nickel dam become 3 μm～25 μm and make the average of crystal grain
Sectional area becomes to be about 300 μm2The sample of terminal electrode, after heating-up temperature is changed over 1200 DEG C
(in other words, after making the condition of the stripping being more prone to nickel dam) has carried out above-mentioned resistance to stripping
Property evaluation test.It addition, in this experiment, by changing heat time heating time so that formed after heating
Different in the thickness T2 (μm) of the oxide-film of the outer surface of nickel dam.This test is shown in table 3
Result.It addition, in table 3, as reference, it is shown heat time heating time in the lump.
[table 3]
As shown in table 3, it is thus identified that the sample making the thickness T2 of oxide-film become below 1.0 μm has excellence
Peel resistance.Consider this is because substantially ensured that the flexibility of nickel dam, and to heat resistanceheat resistant in nickel dam
The endurance of stress improves further.
According to above-mentioned test as a result, it is possible to say to improve peel resistance further, preferably make nickel
The thickness T2 of the oxide-film on the outer surface of layer becomes below 1.0 μm.
Then, become 3 μm～25 μm at the thickness T1 making nickel dam and make the average cross-section of crystal grain
Become 300 μm2On the basis of, the amount (quality %) of regulation carbon (C), thus after making is sent as an envoy to
The sample of the terminal electrode that the hardness of end is different, for each sample, becomes making heating-up temperature
1200 DEG C, make to become 8 minutes heat time heating time after, carried out above-mentioned peel resistance evaluation test.At table
The result of this test shown in 4.It addition, in table 4, as reference, show in the lump in each sample
C content.
[table 4]
As shown in table 4, it is clear that the sample making the hardness of rearward end become 140Hv～180Hv has excellent
Different peel resistance.In view of this is because, it is possible to reduce between terminal electrode and nickel dam produce heat
Differential expansion, the thermal stress putting on nickel dam diminishes further.
According to the result of above-mentioned test, for improving this viewpoint of peel resistance further, it may be said that preferably
Be that the hardness of the rearward end making terminal electrode becomes Vickers hardness 140Hv～180Hv.
It addition, be not limited to the contents of above-mentioned embodiment, such as, can also implement as described below.
Of course it is also possible to other application examples not illustrated below using, modification.
A () in the above-described embodiment, the whole exterior surface area at terminal electrode 6 is provided with nickel dam 35,
As long as but the outer surface at least in the rearward end of terminal electrode 6 is provided with nickel dam 35.
(b) can also for arrange above-mentioned nickel dam 35 electroplating processes last stage opposite end sub-electrode 6
Implement impactive nickel plating to process, and the impactive nickel plating of the surface configuration thin film at terminal electrode 6.Impactive nickel plating
Process such as to use and comprise NiSO4、NiCl2、H3BO3, the highly acid (pH is less than 1) of HCl
Electroplating water solution and implement barrel plating process, by implement impactive nickel plating process and remove be attached to terminal
Impurity on the surface of electrode 6.As a result, it is possible to improve the nickel dam 35 close property to terminal electrode 6 further,
It is thus possible to improve peel resistance and corrosion resistance further.
C () in the above-described embodiment, is provided only with nickel dam 35 on the surface of terminal electrode 6, but also
Can arrange on the surface of nickel dam 35 trivalent chromium layer (more than 95 mass % in contained chromium component by
Trivalent chromium is constituted).Now, it is possible to seek the further raising of corrosion resistance.
D () in the above-described embodiment, spark plug 1 is used for making to produce spark in spark-discharge gap 33 and puts
Electricity, but the structure of the spark plug of the technological thought of the present invention can be applied to be not limited to this.Thus,
Such as, for putting into alternating current to spark-discharge gap and producing AC plasma in spark-discharge gap
Spark plug (AC plasma spark plug), insulation electroceramics top ends there is cavity portion (space)
And be ejected in cavity portion generate isoionic spark plug (plasma jet spark plug) etc. can also apply
The technological thought of the present invention.
E () in the above-described embodiment, engages ground electrode 27 to the top ends at base metal shell 3
Situation embodied, but a part for the base metal shell that can also apply to prune (or
It is welded in a part for the top metal shell of base metal shell in advance) and form the situation of ground electrode
(such as, Japanese Unexamined Patent Publication 2006-236906 publication etc.).
F () in the above-described embodiment, tool engagement portion 19 uses cross section hexagon shape, but about
The shape of tool engagement portion 19 is not limited to such shape.For example, it is also possible to use Bi-HEX
(deforming 12 limits) shape (ISO22977:2005 (E)) etc..
Claims (5)
1. a spark plug, it is characterised in that this spark plug includes:
Insulator, it has the axis hole run through in the axial direction；And
Terminal electrode, it is inserted into from the state that the rear end of above-mentioned insulator is exposed with the rearward end of self
State in axis hole；
Rearward end at above-mentioned terminal electrode is provided with the recess with above-mentioned axis direction as depth direction,
The outer surface of the rearward end of above-mentioned terminal electrode is provided with nickel dam,
The thickness of above-mentioned nickel dam is 3 μm～25 μm, and,
In the cross section orthogonal with the outer surface of above-mentioned nickel dam, constitute the averga cross section of the crystal grain of above-mentioned nickel dam
Amassing is 50 μm2～500 μm2。
Spark plug the most according to claim 1, it is characterised in that
The thickness of above-mentioned nickel dam is 10 μm～20 μm, and,
In above-mentioned cross section, the average cross-section of above-mentioned crystal grain is 200 μm2～400 μm2。
Spark plug the most according to claim 1 and 2, it is characterised in that
The thickness of the oxide-film on the outer surface of above-mentioned nickel dam is below 1.0 μm.
Spark plug the most according to claim 1 and 2, it is characterised in that
Hardness at the rearward end of above-mentioned terminal electrode is Vickers hardness 140Hv～180Hv.
Spark plug the most according to claim 1 and 2, it is characterised in that
Above-mentioned terminal electrode possesses the ring-type outside wall portions of the surrounding surrounding above-mentioned recess,
Above-mentioned recess at least by the inner peripheral surface of above-mentioned outside wall portions and is put down as orthogonal with above-mentioned axis direction
The bottom surface in face is formed, and,
The later half position of the side rearward on above-mentioned axis direction in the inner peripheral surface of above-mentioned outside wall portions upper
State the thickness thickness at least above the nickel dam at above-mentioned bottom surface of nickel dam.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2013099069 | 2013-05-09 | ||
| JP2013-099069 | 2013-05-09 | ||
| JP2014-077465 | 2014-04-04 | ||
| JP2014077465A JP5778819B2 (en) | 2013-05-09 | 2014-04-04 | Spark plug |
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| Publication Number | Publication Date |
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| CN104143766A CN104143766A (en) | 2014-11-12 |
| CN104143766B true CN104143766B (en) | 2016-09-28 |
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| JP (1) | JP5778819B2 (en) |
| CN (1) | CN104143766B (en) |
| DE (1) | DE102014106221B4 (en) |
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| JP6557267B2 (en) * | 2017-01-23 | 2019-08-07 | 日本特殊陶業株式会社 | Spark plug |
| JP6878359B2 (en) * | 2018-07-05 | 2021-05-26 | 日本特殊陶業株式会社 | Spark plug |
| JP6843809B2 (en) * | 2018-10-03 | 2021-03-17 | 日本特殊陶業株式会社 | Spark plug |
| JP7263824B2 (en) * | 2019-02-18 | 2023-04-25 | 株式会社デンソー | Spark plug and manufacturing method thereof |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102484006A (en) * | 2009-09-18 | 2012-05-30 | 日本特殊陶业株式会社 | Spark plug |
| CN103109425A (en) * | 2010-09-15 | 2013-05-15 | 日本特殊陶业株式会社 | Spark plug and main fitting for spark plug |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JPS6264084A (en) * | 1985-09-13 | 1987-03-20 | 日本特殊陶業株式会社 | Ignition plug |
| JPH11339925A (en) * | 1998-05-26 | 1999-12-10 | Ngk Spark Plug Co Ltd | Spark plug |
| KR100842997B1 (en) * | 2003-05-20 | 2008-07-01 | 니혼도꾸슈도교 가부시키가이샤 | Spark Plug and Method for Producing the Same |
| JP2005285486A (en) * | 2004-03-29 | 2005-10-13 | Ngk Spark Plug Co Ltd | Spark plug |
| JP2006236906A (en) * | 2005-02-28 | 2006-09-07 | Ngk Spark Plug Co Ltd | Manufacturing method of spark plug |
| JP5187229B2 (en) * | 2009-02-24 | 2013-04-24 | 三菱マテリアル株式会社 | Thin film temperature sensor and manufacturing method thereof |
| JP2012128948A (en) * | 2010-12-13 | 2012-07-05 | Ngk Spark Plug Co Ltd | Spark plug |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102484006A (en) * | 2009-09-18 | 2012-05-30 | 日本特殊陶业株式会社 | Spark plug |
| CN103109425A (en) * | 2010-09-15 | 2013-05-15 | 日本特殊陶业株式会社 | Spark plug and main fitting for spark plug |
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| Publication number | Publication date |
|---|---|
| DE102014106221B4 (en) | 2021-01-28 |
| DE102014106221A1 (en) | 2014-11-13 |
| JP2014239026A (en) | 2014-12-18 |
| CN104143766A (en) | 2014-11-12 |
| JP5778819B2 (en) | 2015-09-16 |
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