WO2013046650A1 - セラミックグロープラグ - Google Patents
セラミックグロープラグ Download PDFInfo
- Publication number
- WO2013046650A1 WO2013046650A1 PCT/JP2012/006111 JP2012006111W WO2013046650A1 WO 2013046650 A1 WO2013046650 A1 WO 2013046650A1 JP 2012006111 W JP2012006111 W JP 2012006111W WO 2013046650 A1 WO2013046650 A1 WO 2013046650A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- ceramic
- glow plug
- heater
- exposed surface
- electrode extraction
- Prior art date
Links
Images
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02P—IGNITION, OTHER THAN COMPRESSION IGNITION, FOR INTERNAL-COMBUSTION ENGINES; TESTING OF IGNITION TIMING IN COMPRESSION-IGNITION ENGINES
- F02P19/00—Incandescent ignition, e.g. during starting of internal combustion engines; Combination of incandescent and spark ignition
- F02P19/02—Incandescent ignition, e.g. during starting of internal combustion engines; Combination of incandescent and spark ignition electric, e.g. layout of circuits of apparatus having glowing plugs
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23Q—IGNITION; EXTINGUISHING-DEVICES
- F23Q7/00—Incandescent ignition; Igniters using electrically-produced heat, e.g. lighters for cigarettes; Electrically-heated glowing plugs
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02N—STARTING OF COMBUSTION ENGINES; STARTING AIDS FOR SUCH ENGINES, NOT OTHERWISE PROVIDED FOR
- F02N19/00—Starting aids for combustion engines, not otherwise provided for
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23Q—IGNITION; EXTINGUISHING-DEVICES
- F23Q7/00—Incandescent ignition; Igniters using electrically-produced heat, e.g. lighters for cigarettes; Electrically-heated glowing plugs
- F23Q7/001—Glowing plugs for internal-combustion engines
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B3/00—Ohmic-resistance heating
- H05B3/02—Details
- H05B3/03—Electrodes
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B3/00—Ohmic-resistance heating
- H05B3/40—Heating elements having the shape of rods or tubes
- H05B3/42—Heating elements having the shape of rods or tubes non-flexible
- H05B3/46—Heating elements having the shape of rods or tubes non-flexible heating conductor mounted on insulating base
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B3/00—Ohmic-resistance heating
- H05B3/40—Heating elements having the shape of rods or tubes
- H05B3/42—Heating elements having the shape of rods or tubes non-flexible
- H05B3/48—Heating elements having the shape of rods or tubes non-flexible heating conductor embedded in insulating material
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B2203/00—Aspects relating to Ohmic resistive heating covered by group H05B3/00
- H05B2203/027—Heaters specially adapted for glow plug igniters
Definitions
- the present invention relates to a rod-shaped ceramic heater in which a heating element made of a conductive ceramic is embedded and held in a base made of insulating ceramic, and a glow plug including the ceramic heater, and more particularly, connected to the heating element in the base.
- An electrode lead-out portion extending radially outward from the buried rod-shaped conductive portion and exposed to the outer peripheral surface of the ceramic heater is provided, and an inner portion of a metal outer cylinder that fits and holds the ceramic heater from the radially outer side.
- the present invention relates to a ceramic glow plug having a structure in which a peripheral surface is electrically connected to the electrode extraction portion.
- glow plugs used for diesel engine start-up assistance and the like are provided with a cylindrical metal shell, a rod-shaped central shaft, a heater containing a heating element that generates heat when energized, an insulating member, an outer cylinder, a connection terminal, and the like.
- a metal glow plug using a metal sheath heater as a heater or a ceramic glow plug using a heater as a ceramic heater is used in view of performance and cost required for a diesel engine.
- this ceramic glow plug generally has the following configuration. That is, a central shaft with one end protruding toward the rear end side is disposed on the inner peripheral side of the metal shell, and a ceramic heater (hereinafter also simply referred to as a heater) is provided on the front end side of the central shaft. A metal outer cylinder is joined to the tip of the metal shell, and a heater is held by the outer cylinder. On the other hand, on the rear end side of the metal shell, the insulating member is inserted into the gap between the middle shaft and the metal shell, and on the rear end side of the insulating member, the connection terminal is fixed to the middle shaft with the insulating member pressed toward the front end side. ing.
- a method of press-fitting the heater into the outer cylinder can be suitably used for holding the heater.
- a method of using a lubricant to facilitate press-fitting and heating and removing the lubricant after completion of press-fitting is also used. In this way, a radially inward force acts on the heater from the outer cylinder, and the heater is firmly clamped and held.
- the above-mentioned ceramic heater is configured such that a heating element made of conductive ceramic is embedded and held in a base made of insulating ceramic.
- both cathode and anode electrode extraction portions for applying a voltage to the heating element are provided on the rear end side, one electrode extraction portion is electrically connected to the metal shell, and the other electrode extraction portion is It is electrically connected to the central shaft (see, for example, Patent Document 1).
- This electrical connection is realized by the aforementioned press-fitting.
- Both electrode extraction portions are connected to both end portions of the heating element by a pair of rod-shaped conductive portions.
- Both electrode extraction portions and the pair of conductive portions are made of a conductive ceramic like the heating element (see, for example, Patent Document 2).
- the electrode extraction portion, the conductive portion, and the heating element are collectively referred to as a resistor.
- JP 2002-364842 A Japanese Patent Laid-Open No. 2007-240080
- the resistor has a configuration in which the resistor material includes a metal component such as W (tungsten) or Mo (molybdenum) in a larger amount than the base so that the resistor has conductivity. .
- a resistor has a larger thermal expansion coefficient than a base
- the improvement in strength due to the action of the compressive stress can be suitably used.
- the electrode extraction portion is exposed on the outer peripheral surface of the heater. For this reason, tensile stress from the exposed part of the electrode extraction part acts on a part of the substrate around the electrode extraction part (hereinafter, this part is also referred to as an electrode part).
- this part is also referred to as an electrode part.
- the integrated assembly of the heater and the outer cylinder is heated to about 300 ° C. Since the outer cylinder is made of metal, its thermal expansion coefficient is much larger than that of the ceramic heater. Therefore, the outer cylinder undergoes thermal expansion due to heating during the removal of the lubricant, and the expansion in the axial direction of the thermal expansion causes a tensile stress in the axial direction of the heater. At this time, the radially inward compressive stress due to the press-fitting and the tensile stress in the axial direction act on the heater. As described above, since the electrode portion of the heater has low strength, the compressive stress and the tensile stress act synergistically, so that the ceramic heater may be damaged starting from the electrode portion.
- the above-described problem is not limited to the ceramic glow plug in which the heater is press-fitted and held in the outer cylinder, and the heater may be similarly generated in the ceramic glow plug in which the heater is held in the outer cylinder via the brazing material layer. is there.
- the present invention is a glow plug having a configuration in which a metal outer cylinder holds ceramic heaters having different thermal expansion coefficients between a resistor and a base, and a change in the constituent material of the heater or the outer cylinder To improve resistance to breakage in the electrode part of the ceramic heater that may occur after assembly with the outer cylinder, without changing the dimensions, materials, etc., and without impairing the electrical connection with the outer cylinder at the electrode extraction part Is.
- the ceramic glow plug of the present invention is A base made of insulating ceramic and having a columnar shape in the axial direction; A heating element made of a conductive ceramic and embedded in the front end portion of the base and generating resistance heat by energization, a conductive portion connected to both ends of the heating element and extending rearward in the axial direction, and the conductive portion A resistor including an electrode extraction portion extending in a radial direction from at least one of the first electrode and exposed to the outer peripheral surface of the base body;
- the ceramic heater consisting of A ceramic glow plug comprising a metal cylindrical member that holds the ceramic heater therein and that conducts in contact with the exposed surface of the electrode extraction portion,
- the axial dimension and the circumferential dimension of the exposed surface of the electrode extraction part are both 1.0 to 1.8 mm.
- the ceramic glow plug of the present invention is Compressive residual stress in a specific region of 0.3 mm from the front end of the exposed surface of the electrode extraction portion of the base body and 0.3 mm from the rear end of the exposed surface, compressive residual stress outside the specific region of the base body
- the ratio is 50% or more.
- the ceramic glow plug of the present invention is The axial dimension of the exposed surface of the electrode extraction portion is formed smaller than the circumferential dimension.
- the ceramic glow plug of the present invention is The shape of the exposed surface of the electrode extraction portion does not have a corner portion.
- the ceramic glow plug of the present invention is The ceramic heater is press-fitted into the cylindrical member.
- both the axial dimension and the circumferential dimension on the exposed surface of the electrode extraction portion are 1.0 to 1.8 mm even if the thermal expansion coefficient differs between the resistor and the substrate.
- the tolerance with respect to breakage of a ceramic heater can be improved, without impairing the electrical connection with the cylindrical member in an electrode extraction part.
- the thermal expansion coefficient of the resistor is different from the thermal expansion coefficient of the substrate by 0.3 ppm / K or more, the above-described effects can be further exhibited.
- the ceramic glow plug of configuration 2 the ratio between the compressive residual stress in the specific region and the compressive residual stress outside the specific region of the base (compressed residual stress of the base in the specific region / compressive residual stress outside the specific region). Therefore, the strength of the substrate around the exposed surface can be improved.
- the resistance to breakage of the ceramic heater can be further improved.
- the exposed surface of the electrode extraction portion has a shape having no corners, local stress concentration can be avoided, and the strength of the substrate around the exposed surface can be avoided. Can be further improved.
- the ceramic glow plug in which the ceramic heater is press-fitted into the cylindrical member, it is difficult to achieve both electrical connection with the cylindrical member at the electrode extraction portion and resistance to breakage of the ceramic heater. Therefore, in the ceramic glow plug as in the present configuration 5, the above configurations 1 to 4 are particularly effective.
- FIG. 1A is a front view of the glow plug 1
- FIG. 1B is a longitudinal sectional view of the glow plug 1.
- FIG. 2 is a partially enlarged cross-sectional view centering on the ceramic heater 4.
- the lower side of the drawing will be described as the front end side of the glow plug 1 (ceramic heater 4), and the upper side will be described as the rear end side.
- the glow plug 1 includes a metal shell 2, a center shaft 3, a ceramic heater 4, an outer cylinder 5, a connection terminal 6, and the like.
- the metal shell 2 is formed of a predetermined metal material (for example, an iron-based material such as S45C) and has a shaft hole 7 extending along the direction of the axis CL1.
- a tapered portion 7 a is formed that tapers toward the front end side.
- the tip end side of the shaft hole 7 with respect to the tapered portion 7a is formed in a straight shape (so as to have the same inner diameter).
- a male screw portion 8 for attaching the glow plug 1 to a female screw portion formed in a mounting hole of a cylinder head of the engine is formed on the outer periphery of the central portion of the metal shell 2 in the longitudinal direction.
- a hook-shaped tool engaging portion 9 having a hexagonal cross section is formed on the outer periphery of the rear end portion of the metal shell 2, and when attaching the glow plug 1 (male screw portion 8) to the mounting hole, A tool used in the tool engaging portion 9 is engaged.
- the shaft 3 in the metal shell 2 accommodates the middle shaft 3 made of metal and having a round bar shape.
- a tip small-diameter portion 3 a that is formed to have a smaller diameter than the rear end side is formed at the tip portion of the intermediate shaft 3.
- the central shaft 3 is connected to the rear end portion of the ceramic heater 4 via a cylindrical ring member 10 formed of a metal material (for example, an iron-based material such as SUS). More specifically, the rear end portion of the ceramic heater 4 is press-fitted into the front end portion of the inner hole 10 a of the ring member 10, and the front end small diameter portion 3 a with respect to the rear end portion of the inner hole 10 a of the ring member 10. In the state in which the intermediate shaft 3 and the ring member 10 are joined by laser welding or the like, the intermediate shaft 3 and the ceramic heater 4 are mechanically and electrically connected via the ring member 10.
- the metal connection terminal 6 is caulked and fixed to the rear end of the middle shaft 3.
- an insulating bush 11 made of an insulating material is provided between the front end portion of the connection terminal 6 and the rear end portion of the metal shell 2 in order to prevent direct electrical conduction therebetween. More specifically, the insulating bush 11 includes a flange portion 11a that protrudes radially outward on the rear end side thereof, and a small-diameter portion 11b that is formed with a smaller diameter than the flange portion 11a on the front end side thereof. And have.
- the insulating bush 11 is provided in a state where the small diameter portion 11b is fitted to the rear end portion of the shaft hole 7 and the flange portion 11a is sandwiched between the connection terminal 6 and the metal shell 2. ing. Furthermore, in order to improve the airtightness in the shaft hole 7, an O-ring 12 made of an insulating material is interposed between the metal shell 2 and the middle shaft 3 and is locked to the tapered portion 7 a. Is provided.
- a constricted portion 3b is formed on the distal end side of the middle shaft 3 and its outer diameter is reduced toward the distal end side.
- the constricted portion 3b reduces stress transmitted to the central shaft 3 and the like.
- the outer cylinder 5 is formed in a cylindrical shape from a predetermined metal material (for example, SUS310). Further, the outer cylinder 5 holds an intermediate portion along the direction of the axis CL ⁇ b> 1 of the ceramic heater 4, and the tip of the ceramic heater 4 is exposed from the tip of the outer cylinder 5. Further, the outer cylinder 5 has a small-diameter portion 5a formed relatively thin on the distal end side, a tapered portion 5b tapering to the distal end side on the rear end side with respect to the small-diameter portion 5a, and the tapered portion 5b.
- a predetermined metal material for example, SUS310
- a large diameter portion 5c formed continuously from the rear end and having an outer diameter substantially the same as the outer diameter of the front end of the metal shell 2, and the front end portion of the shaft hole 7 on the rear end side of the large diameter portion 5c. And an engaging portion 5d having an outer diameter substantially the same as the inner diameter. Then, in a state where the engaging portion 5d is fitted to the distal end portion of the shaft hole 7, a melting portion is formed on the contact surface of the metal shell 2 and the outer cylinder 5 by laser welding or the like, An outer cylinder 5 is joined to the metal shell 2.
- the tapered portion 5b plays a role as a seal for ensuring airtightness with the combustion chamber.
- the ceramic heater 4 is made of an insulating ceramic, has a round bar-like base body 21 having substantially the same diameter extending in the direction of the axis CL1, and a long thin U-shaped resistor made of conductive ceramic. 22 is held in an embedded state.
- the outer diameter of the ceramic heater 4 is, for example, 2.5 to 4.0 mm.
- the resistor 22 includes a pair of rod-like conductive portions 23 and 24 and a connecting portion 25 that connects the tip portions of the conductive portions 23 and 24. Is the heat generating portion 26.
- the heating portion functions as a so-called heating resistor, and has a substantially U-shaped cross section along the curved surface at the tip portion of the ceramic heater 4 formed in a curved shape. Further, in the present embodiment, the cross-sectional area of the heat generating portion 26 is configured to be smaller than the cross-sectional areas of the conductive portions 23 and 24, and the heat generating portion 26 positively generates heat when energized. It is like that.
- the connecting portion 25 corresponds to the heating element in the present invention.
- Si 3 N 4 silicon nitride
- Si 3 N 4 is mainly used as the insulating ceramic material constituting the base 21.
- the material constituting the resistor 22 contains silicon nitride as a main component and contains WC (tungsten carbide) (for example, 60 to 70% by mass when the total of silicon nitride and tungsten carbide is 100% by mass).
- Conductive ceramic material material having conductivity after firing is used.
- the thermal expansion coefficient of the substrate 21 is, for example, 3.3 to 4.0 ppm / K
- the thermal expansion coefficient of the resistor 22 is, for example, 3.6 to 4.2 ppm / K.
- the conductive portions 23 and 24 extend substantially parallel to each other toward the rear end side of the ceramic heater 4.
- an electrode extraction portion 27 protrudes in the radial direction.
- the electrode extraction part 27 is exposed on the outer peripheral surface of the ceramic heater 4.
- the electrode extraction portion 28 protrudes in the radial direction, and the electrode extraction portion 28 is exposed on the outer peripheral surface of the ceramic heater 4.
- the electrode extraction portion 27 of the one conductive portion 23 is located on the rear end side with respect to the electrode extraction portion 28 of the other conductive portion 24 along the direction of the axis CL1.
- the exposed portion of the electrode extraction portion 27 is in contact with the inner peripheral surface of the ring member 10.
- electrical continuity between the middle shaft 3 connected to the ring member 10 and the conductive portion 23 is achieved.
- the exposed portion of the electrode extraction portion 28 is in contact with the inner peripheral surface of the outer cylinder 5.
- electrical conduction between the metal shell 2 joined to the outer cylinder 5 and the conductive portion 24 is achieved. That is, in the present embodiment, the central shaft 3 and the metal shell 2 function as an anode / cathode for energizing the heat generating portion 26 of the ceramic heater 4 in the glow plug 1.
- the electrode extraction part 28 which is the main part of the present invention will be described together with the evaluation results after the description of the manufacturing method.
- the above-described glow plug 1 is assembled in a mounting hole of a cylinder head of an internal combustion engine. At this time, the outer cylinder 5 comes into contact with the cylinder head, whereby the metal shell 2 is grounded.
- the ring member 10 is formed by cutting a pipe material made of an iron-based material such as SUS630 into a predetermined length, and arranging the pipe material into a predetermined cylindrical shape.
- the pipe member made of a predetermined metal material for example, SUS430
- the surface of the ring member 10 and the outer cylinder 5 is subjected to a plating process such as Au plating.
- the rear end portion of the separately manufactured ceramic heater 4 is press-fitted into the front end portion of the inner hole 10 a of the ring member 10.
- the ceramic heater 4 is press-fitted into the inner hole of the outer cylinder 5.
- the outer cylinder 5 is fixed by being separated in the direction of the axis CL ⁇ b> 1 so as not to contact the ring member 10.
- an appropriate amount (Paskin M30 (trade name: Kyoeisha Chemical Co., Ltd.)) is applied as a lubricant.
- the integrated assembly with the cylinder 5 is put into a heating furnace and heated to about 300 ° C. to decompose and remove the lubricant.
- the pre-manufactured middle shaft 3 is fitted into the rear end portion of the inner hole 10a, and then a laser beam is irradiated along the contact surfaces of the ring member 10 and the middle shaft 3, so that the ring member 10 and the middle shaft 3 are irradiated. Join.
- the central shaft 3, the ceramic heater 4, the outer cylinder 5, and the ring member 10 are integrally formed.
- the metal shell 2 is manufactured. That is, the metal shell 2 including the male screw portion 8 and the tool engaging portion 9 is obtained by cutting a pipe material made of a predetermined metal material into a predetermined length and then performing a cutting process or a rolling process. . Moreover, you may perform rust prevention processes, such as plating, as needed.
- the outer cylinder 5 in which the middle shaft 3 and the ceramic heater 4 are integrated and the metal shell 2 are joined. That is, after the engaging portion 5 d of the outer cylinder 5 is fitted into the shaft hole 7 of the metal shell 2, the laser beam is irradiated along the contact surfaces of the outer cylinder 5 and the metal shell 2. As a result, the melted portion is formed, and the outer cylinder 5 and the metal shell 2 that are integrated with the intermediate shaft 3 and the ceramic heater 4 are joined.
- the insulating bush 11 and the O-ring 12 are arranged at a predetermined position between the metal shell 2 and the middle shaft 3, and a connection formed in advance at the rear end portion of the middle shaft 3 protruding from the rear end side of the metal shell 2.
- the glow plug 1 is obtained by crimping and fixing the terminal 6.
- the shape of the electrode extraction portion 28 is characteristic, but a conventionally known manufacturing method can be used for other configurations. Therefore, it is manufactured through a series of steps of formation of an unfired resistor, integration with a base material, firing, and external polishing (see FIG. 3).
- the ceramic heater 4 shrinks or deforms during a firing process such as hot pressing, when manufacturing an unfired resistor (resistor before firing) by injection molding, the shape of the electrode extraction portion described later is exhibited. It is formed in consideration of the shrinkage and the like.
- the ceramic glow plug of the present invention thus manufactured realizes a good electrical connection with the outer cylinder and has excellent performance in breakage resistance. Next, the evaluation test and the result of the ceramic glow plug according to the present invention will be described.
- test ceramic heaters formed as described above had an outer diameter of 3.1 mm and a length of 42 mm.
- shape of the exposed surface of the electrode extraction portion of the manufactured test product is a circle or an ellipse. Thus, in this invention, it is set as the shape which does not have a corner
- the maximum length in each direction is 0.5 mm, 1.0 mm, 1.8 m, 2.0 mm, and 3.0 mm in both the axial direction and the circumferential direction, and a total of 25 patterns of these combinations. An evaluation test was conducted.
- the outer cylinder used for the ceramic glow plug manufactured in the evaluation test has an outer diameter of 8.0 mm, an inner diameter of 3.05 mm, and a length of 25 mm.
- the axial length of the portion having the maximum outer diameter of the diameter portion was 4.0 mm.
- ⁇ Evaluation items are checking whether resistance failure has occurred in the heater as well as resistance to breakage of the heater.
- the test methods are as follows.
- the resistance value is measured by energizing the ceramic glow plug, and the resistance value rises by more than 20% from the design resistance value before dropping.
- the number of test specimens was counted to calculate the incidence of resistance failure.
- Table 2 In both tests, the symbol “ ⁇ ” indicates that the incidence of defects is 0.1% or less, “ ⁇ ” is 0.1% or more and less than 1%, and “X” is 1% or more.
- the number of evaluations was 300 in all cases. Therefore, in this evaluation test, the symbol “ ⁇ ” means that no defect has occurred, the symbol “ ⁇ ” has one or two defects, and the symbol “X” has three. It means that the above defects occurred.
- the failure rate of the heater is extremely low and there is no problem if the shape of the exposed surface of the electrode extraction part is 1.8 mm or less in both the axial direction and the circumferential direction. It was. In addition, it was confirmed that the shape of the exposed surface is preferably 1.0 mm or more for resistance failure. It has been confirmed that similar results to those described above can be obtained when the outer diameter of the ceramic heater is 2.5 to 4.0 mm.
- Example 4 corresponds to Example 1 described above except that the lubricant removal temperature is different.
- breakage failure did not occur in Example 4
- breakage failure occurred in Example 4 of this test in which the lubricant removal temperature was excessively increased.
- no breakage failure occurred in Examples 5 and 6
- the shape of the sixth embodiment in which the axial dimension of the exposed surface is smaller than the circumferential dimension is larger than that of the fourth embodiment in which the axial dimension of the exposed surface is larger than the circumferential dimension.
- the durability against breakage failure improved as it approached.
- This result confirmed the significance that the axial dimension of the exposed surface was formed smaller than the circumferential dimension. This is presumably because the tensile stress that the exposed surface of the electrode extraction portion applies to the boundary of the exposed surface in the axial direction mainly depends on the axial dimension of the exposed surface.
- the conductive part contains a larger amount of metal element than the base, the conductive part has a larger thermal expansion coefficient than the base. For this reason, in the cooling stage after firing in the manufacturing process of the heater, the amount of contraction of the conductive portion is larger than that of the substrate, and tensile stress is generated in the substrate.
- the stress acts as a compressive stress on the surface of the heater (base). Since the compressive stress is acting, the strength in the portion, that is, the base portion where the conductive portion is embedded is apparently improved.
- the exposed conductive portion contracts so as to pull the surrounding substrate, thereby canceling the compression stress described above. That is, it is difficult to expect the effect of improving the strength due to the compressive stress at the boundary between the exposed surface and the substrate.
- a configuration is adopted in which the area of the exposed surface is reduced to reduce the proportion of the compressive stress cancelled.
- the structure in which the area of the exposed surface is reduced improves the strength around the exposed surface. This effect can be more effectively achieved by avoiding the occurrence of local stress concentration by adopting a configuration in which the shape of the exposed surface does not have corners, that is, a shape similar to a circle or an ellipse. is there.
- Example 1 Example 1 and Comparative Example 1 described above.
- the surface residual stress of each heater was measured for each heater.
- As a measuring method an X-ray residual stress measuring method was used, and a 2 ⁇ -sin2 ⁇ -ray method was used.
- For stress measurement 131.55 ° of ⁇ -Si 3 N 4 (212) having a high peak intensity on the high angle side was used.
- the collimator had a diameter of 0.5 mm, a 2 ⁇ sampling width of 0.1 °, and a counting time of 1000 seconds.
- Cr-K ⁇ was used for the X-ray tube.
- X-rays were irradiated at a plurality of incident angles to obtain diffraction angles.
- the residual stress was calculated from the slope of the 2 ⁇ -sin2 ⁇ diagram created from the diffraction angle with respect to the incident angle.
- the residual stress was measured at four points, each having a predetermined distance in the axial direction from the base point, with the boundary between the exposed surface and the substrate at the electrode extraction portion as the base point (see the ST1 and ST2 positions in FIG. 5).
- the residual stress at the boundary is originally measured.
- the electrode extraction part on the exposed surface is measured.
- a diffraction peak is generated due to the constituent material, and accurate 2 ⁇ measurement cannot be performed.
- the peak intensity is reduced when the collimator diameter is 0.5 mm or less, and reliable stress measurement cannot be performed.
- the residual stress at the boundary the residual stress at a position of 0.30 mm from the interface having a radius of 0.25 mm or more of the collimator diameter, which is the minimum distance not including the electrode material in the measurement range, was measured.
- the compression residual stress ratio of the exposed surface boundary with respect to the conductive portion in each sample was 71% in Example 1, 50% in Example 2, and 45% in Comparative Example 1.
- the conductive portion indicates a position where the stress is sufficiently far from the boundary of the exposed surface and the stress is stable.
- “not having a corner” is not limited to a circle or an ellipse, and may be, for example, a shape obtained by rounding a substantially rectangular corner. If the magnitude of R at that time, that is, the radius of curvature is 0.1 mm or more, for example, it corresponds to “no corners”.
- the present invention it is possible to improve the strength of the electrode portion of the ceramic heater without changing the constituent material of the heater or changing the dimensions and materials of the outer cylinder.
- the present invention does not limit changes in the constituent material of the heater or various changes in the outer cylinder, and can be employed in any glow plug that requires improvement in the strength of the electrode portion of the ceramic heater.
- the ceramic heater 4 is press-fitted and held in the inner hole of the outer cylinder 5, but the ceramic heater is held in the inner hole of the outer cylinder via a brazing material layer. You may do it.
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Resistance Heating (AREA)
Abstract
Description
絶縁性セラミックからなり軸方向に柱状をなす基体と、
導電性セラミックからなり前記基体の先端部に埋設され通電によって抵抗発熱する発熱素子と、当該発熱素子の両端部に接続され前記軸方向の後方へ向けて延設される導電部と、当該導電部の少なくとも一方から径方向へ向けて延設され前記基体の外周面へ露出する電極取出部とを備えてなる抵抗体と、
からなるセラミックヒータを備え、
自身の内部に前記セラミックヒータが保持され、前記電極取出部の露出面と接触して導通する金属製の筒状部材とを備えたセラミックグロープラグであって、
前記電極取出部の露出面の前記軸方向寸法及び前記周方向寸法が共に1.0~1.8mmであることを特徴とする。
前記基体のうち前記電極取出部の露出面の先端から0.3mm、及び当該露出面の後端から0.3mmの特定領域における圧縮残留応力の、前記基体のうち前記特定領域外における圧縮残留応力に対する比が50%以上であることを特徴とする。
前記電極取出部の露出面の前記軸方向寸法が前記周方向寸法に対して小さく形成されていることを特徴とする。
前記電極取出部の露出面の形状は、角部を持たないことを特徴とする。
前記セラミックヒータは、前記筒状部材の内部に圧入嵌合されることを特徴とする。
前述の外筒へセラミックヒータを圧入し、潤滑剤を加熱除去した。室温まで冷却した後にヒータに折損が生じているか否かを確認し、その本数をカウントして折損不良の発生率を算出した。この結果を表1に示す。なお、潤滑剤の除去は、大気雰囲気の加熱炉を用いてで300℃に加熱し、その後室温まで自然冷却する方法を用いた。
[落下による抵抗不良の発生率]
上記折損不良の試験と同様の手順によりセラミックヒータを外筒へ圧入し、折損が生じていないものを用いて前述の手順によりグロープラグの完成品を製造する。完成したセラミックグロープラグを50cmの高さからコンクリート床へ落下させた後、セラミックグロープラグへ通電して抵抗値を測定し、落下前、すなわち設計抵抗値から20%以上の抵抗値の上昇が生じた試験品の本数をカウントして抵抗不良の発生率を算出した。この結果を表2に示す。なお、両試験とも符号「○」は不良の発生率が0.1%以下、「△」は0.1%以上1%未満、「×」は1%以上であることを示している。また、評価本数はいずれも300本であった。したがって、本評価試験においては符号「○」は不良が1本も発生していないことを意味し、符号「△」は不良の発生が1本又は2本であり、符号「×」は3本以上の不良が発生したことを意味している。
上述の評価試験におけるヒータの外径に対する依存性について確認した。評価方法は上述の折損不良の発生率を確認した試験と同様であり、電極取出部の露出面の形状を軸方向に1.7mm、周方向に1.0mmとした実施例1~3と、軸方向に2.0mm、周方向に2.0mmとした比較例1~3のそれぞれにつき、ヒータの外径をφ3.1mm、φ3.3mm、φ3.5mmとした計6パターンの試験品を準備して評価試験を行った。結果を表3に示す。
次いで、電極取出部の露出面における軸方向寸法と周方向寸法との関係を確認した試験について説明する。評価方法は上述の折損不良の発生率を確認した試験と同様である。ヒータの負荷に対する耐性を確認すべく潤滑剤の除去温度を350℃と過剰に上げてヒータの折損不良の発生率を確認した。結果を表4に示す。なお、露出面における軸方向寸法と周方向寸法との関係性を評価するために実施例4~6の露出面の面積は同一となるよう、それぞれの寸法を設定した。
本発明のセラミックヒータは、導電部が基体に比較して多量の金属元素を含有するため、熱膨張係数も導電部の方が基体に比較して大きく構成されている。このため、ヒータの製造過程における焼成後の冷却段階では導電部の収縮量は基体のそれよりも多く、基体には引張り応力が生じる。ヒータ(基体)の表面では当該応力は圧縮応力として作用する。圧縮応力が作用しているので、当該部位、すなわち内部に導電部が埋設されている基体部位における強度は見かけ上では向上する。一方、導電部が露出された電極取出部(露出面)では、露出した部位の導電部(露出面)がその周囲の基体を引っ張るように収縮するため上述した圧縮応力を相殺してしまう。すなわち、露出面における基体との境界では上述の圧縮応力による強度の向上効果を期待することが難しい。
評価試験に用いたサンプルは前述の実施例1と比較例1であった。それぞれのヒータについてヒータ単体の表面残留応力を測定した。測定方法はX線残留応力測定法を用い、2θ-sin2ψ線法を用いた。応力測定には、高角度側でピーク強度が高いβ-Si3N4(212)の131.55°を使用した。コリメーターはφ0.5mm、2θサンプリング幅は0.1°、計数時間は1000秒であった。X線管球にはCr-Kαを用いた。本方法では、複数の入射角でX線を照射し、回折角を得た。入射角に対する回折角から作成した、2θ-sin2ψ線図の傾きから残留応力を算出した。また残留応力の測定は、電極取出部における露出面と基体との境界を基点(図5におけるST1,ST2位置参照)とし、当該基点から軸方向に所定距離それぞれ離れた4点にて行った。
2 主体金具
21 基体
22 抵抗体
23,24 導電部
25 連結部
26 発熱部
3 中軸
4 セラミックヒータ
5 外筒
Claims (5)
- 絶縁性セラミックからなり軸方向に柱状をなす基体と、
導電性セラミックからなり前記基体の先端部に埋設され通電によって抵抗発熱する発熱素子と、当該発熱素子の両端部に接続され前記軸方向の後方へ向けて延設される導電部と、当該導電部の少なくとも一方から径方向へ向けて延設され前記基体の外周面へ露出する電極取出部とを備えてなる抵抗体と、
からなるセラミックヒータを備え、
自身の内部に前記セラミックヒータが保持され、前記電極取出部の露出面と接触して導通する金属製の筒状部材とを備えたセラミックグロープラグであって、
前記電極取出部の露出面の前記軸方向寸法及び前記周方向寸法が共に1.0~1.8mmであることを特徴とするセラミックグロープラグ。 - 前記基体のうち前記電極取出部の露出面の先端から0.3mm、及び当該露出面の後端から0.3mmの特定領域における圧縮残留応力の、前記基体のうち前記特定領域外における圧縮残留応力に対する比が50%以上であることを特徴とする請求項1に記載のセラミックグロープラグ。
- 前記電極取出部の露出面の前記軸方向寸法が前記周方向寸法に対して小さく形成されていることを特徴とする請求項1または2に記載のセラミックグロープラグ。
- 前記電極取出部の露出面の形状は、角部を持たないことを特徴とする請求項1から3のいずれか1項に記載のセラミックグロープラグ。
- 前記セラミックヒータは、前記筒状部材の内部に圧入嵌合されることを特徴とする請求項1から5のいずれか1項に記載のセラミックグロープラグ。
Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US14/233,049 US9644597B2 (en) | 2011-09-27 | 2012-09-25 | Ceramic glow plug |
JP2013503689A JP5632958B2 (ja) | 2011-09-27 | 2012-09-25 | セラミックグロープラグ |
KR1020147009231A KR101579015B1 (ko) | 2011-09-27 | 2012-09-25 | 세라믹 글로 플러그 |
EP12835782.9A EP2762783B1 (en) | 2011-09-27 | 2012-09-25 | Ceramic glow plug |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2011-211145 | 2011-09-27 | ||
JP2011211145 | 2011-09-27 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2013046650A1 true WO2013046650A1 (ja) | 2013-04-04 |
Family
ID=47994733
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP2012/006111 WO2013046650A1 (ja) | 2011-09-27 | 2012-09-25 | セラミックグロープラグ |
Country Status (5)
Country | Link |
---|---|
US (1) | US9644597B2 (ja) |
EP (1) | EP2762783B1 (ja) |
JP (1) | JP5632958B2 (ja) |
KR (1) | KR101579015B1 (ja) |
WO (1) | WO2013046650A1 (ja) |
Families Citing this family (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US10352565B2 (en) * | 2012-08-08 | 2019-07-16 | Ngk Spark Plug Co., Ltd. | Glow plug |
CN105156251A (zh) * | 2015-08-27 | 2015-12-16 | 扬州市飞鹰电子科技有限公司 | 一种柴油发动机氧化物陶瓷电热塞及其生产方法 |
JP6370754B2 (ja) * | 2015-09-10 | 2018-08-08 | 日本特殊陶業株式会社 | セラミックヒータおよびグロープラグ |
DE102016108592B4 (de) | 2016-05-10 | 2018-06-28 | Borgwarner Ludwigsburg Gmbh | Glühkerze und Verfahren zum Herstellen einer Glühkerze |
USD906383S1 (en) * | 2018-08-17 | 2020-12-29 | Hotset Gmbh | Electrical heater for injection-molding machine |
KR20230136300A (ko) | 2022-03-18 | 2023-09-26 | 최윤혜 | 입김을 이용한 스마트기기 앱 제어방법 |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2002299009A (ja) * | 2001-03-29 | 2002-10-11 | Ngk Spark Plug Co Ltd | セラミックヒーター |
JP2002364842A (ja) | 2001-06-07 | 2002-12-18 | Ngk Spark Plug Co Ltd | グロープラグ及びグロープラグの製造方法 |
JP2006049279A (ja) * | 2004-06-29 | 2006-02-16 | Ngk Spark Plug Co Ltd | セラミックヒータ、グロープラグ及びセラミックヒータの製造方法 |
JP2007240080A (ja) | 2006-03-09 | 2007-09-20 | Ngk Spark Plug Co Ltd | セラミックヒータ及びグロープラグ |
Family Cites Families (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH10332149A (ja) * | 1997-03-31 | 1998-12-15 | Ngk Spark Plug Co Ltd | セラミックヒータ |
JP4559671B2 (ja) * | 2001-08-28 | 2010-10-13 | 日本特殊陶業株式会社 | グロープラグ及びその製造方法 |
JP3816073B2 (ja) * | 2003-01-28 | 2006-08-30 | 日本特殊陶業株式会社 | グロープラグ及びグロープラグの製造方法 |
US7705273B2 (en) * | 2004-04-07 | 2010-04-27 | Ngk Spark Plug Co., Ltd. | Ceramic heater, method of producing the same, and glow plug using a ceramic heater |
EP1612486B1 (en) | 2004-06-29 | 2015-05-20 | Ngk Spark Plug Co., Ltd | Glow plug |
WO2007108491A1 (ja) * | 2006-03-21 | 2007-09-27 | Ngk Spark Plug Co., Ltd. | セラミックヒータ及びグロープラグ |
US20100213188A1 (en) * | 2006-03-21 | 2010-08-26 | Ngk Spark Plug Co., Ltd. | Ceramic heater and glow plug |
EP2107854B1 (en) * | 2006-05-18 | 2012-04-11 | NGK Spark Plug Co., Ltd. | Ceramic heater and glow plug |
KR101375989B1 (ko) * | 2008-02-20 | 2014-03-18 | 니혼도꾸슈도교 가부시키가이샤 | 세라믹 히터 및 글로우 플러그 |
EP2701459B1 (en) * | 2011-04-19 | 2018-03-28 | NGK Spark Plug Co., Ltd. | Ceramic heater and manufacturing method thereof |
JP6140955B2 (ja) * | 2011-12-21 | 2017-06-07 | 日本特殊陶業株式会社 | セラミックヒータの製造方法 |
-
2012
- 2012-09-25 KR KR1020147009231A patent/KR101579015B1/ko active IP Right Grant
- 2012-09-25 JP JP2013503689A patent/JP5632958B2/ja active Active
- 2012-09-25 US US14/233,049 patent/US9644597B2/en active Active
- 2012-09-25 EP EP12835782.9A patent/EP2762783B1/en active Active
- 2012-09-25 WO PCT/JP2012/006111 patent/WO2013046650A1/ja active Application Filing
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2002299009A (ja) * | 2001-03-29 | 2002-10-11 | Ngk Spark Plug Co Ltd | セラミックヒーター |
JP2002364842A (ja) | 2001-06-07 | 2002-12-18 | Ngk Spark Plug Co Ltd | グロープラグ及びグロープラグの製造方法 |
JP2006049279A (ja) * | 2004-06-29 | 2006-02-16 | Ngk Spark Plug Co Ltd | セラミックヒータ、グロープラグ及びセラミックヒータの製造方法 |
JP2007240080A (ja) | 2006-03-09 | 2007-09-20 | Ngk Spark Plug Co Ltd | セラミックヒータ及びグロープラグ |
Non-Patent Citations (1)
Title |
---|
See also references of EP2762783A4 |
Also Published As
Publication number | Publication date |
---|---|
US20140196680A1 (en) | 2014-07-17 |
KR20140057387A (ko) | 2014-05-12 |
JPWO2013046650A1 (ja) | 2015-03-26 |
KR101579015B1 (ko) | 2015-12-18 |
JP5632958B2 (ja) | 2014-11-26 |
EP2762783A1 (en) | 2014-08-06 |
US9644597B2 (en) | 2017-05-09 |
EP2762783B1 (en) | 2019-09-04 |
EP2762783A4 (en) | 2015-02-25 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
JP5632958B2 (ja) | セラミックグロープラグ | |
US6744015B2 (en) | Heater and method for manufacturing the same | |
JP5525106B2 (ja) | セラミックグロープラグ | |
US8410403B2 (en) | Glow plug with improved seal, heater probe assembly therefor and method of construction thereof | |
CN108352680B (zh) | 火花塞 | |
EP1239222A2 (en) | Ceramic heater device and method for manufacturing the device | |
JP6392000B2 (ja) | グロープラグ | |
WO2003052323A1 (fr) | Bougie de prechauffage pour moteur diesel et procede de fabrication de ladite bougie de prechauffage | |
US7034253B2 (en) | Ceramic heater with ring member electrically connecting the heater to lead terminal core rod | |
JP4425017B2 (ja) | ヒータ | |
JP4921039B2 (ja) | スパークプラグ | |
JP6567340B2 (ja) | セラミックヒータ及びその製造方法、並びにグロープラグ及びその製造方法 | |
JP6665495B2 (ja) | セラミックヒータ | |
US20180351331A1 (en) | Spark plug | |
JP6944289B2 (ja) | グロープラグ | |
JP4019004B2 (ja) | セラミックヒータ及びそれを用いたグロープラグ | |
JP6101145B2 (ja) | ヒータモジュールの製造方法、および、グロープラグの製造方法 | |
JP5301635B2 (ja) | スパークプラグ | |
JP6807660B2 (ja) | セラミックヒータ素子、および、セラミックグロープラグ | |
JP6707404B2 (ja) | スパークプラグ | |
JP2010080452A (ja) | セラミックヒーター装置 | |
CN111194511A (zh) | 火花塞 | |
JP2019149272A (ja) | ヒータ | |
JP2017111983A (ja) | 点火プラグ | |
JP2011149846A (ja) | 圧力センサ |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
ENP | Entry into the national phase |
Ref document number: 2013503689 Country of ref document: JP Kind code of ref document: A |
|
121 | Ep: the epo has been informed by wipo that ep was designated in this application |
Ref document number: 12835782 Country of ref document: EP Kind code of ref document: A1 |
|
WWE | Wipo information: entry into national phase |
Ref document number: 2012835782 Country of ref document: EP |
|
WWE | Wipo information: entry into national phase |
Ref document number: 14233049 Country of ref document: US |
|
NENP | Non-entry into the national phase |
Ref country code: DE |
|
ENP | Entry into the national phase |
Ref document number: 20147009231 Country of ref document: KR Kind code of ref document: A |