JP2001132950A - Ceramic heater and glow plug using it - Google Patents
Ceramic heater and glow plug using itInfo
- Publication number
- JP2001132950A JP2001132950A JP30894499A JP30894499A JP2001132950A JP 2001132950 A JP2001132950 A JP 2001132950A JP 30894499 A JP30894499 A JP 30894499A JP 30894499 A JP30894499 A JP 30894499A JP 2001132950 A JP2001132950 A JP 2001132950A
- Authority
- JP
- Japan
- Prior art keywords
- ceramic heater
- heater
- ceramic
- lead wire
- glow plug
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Landscapes
- Resistance Heating (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明はセラミックヒータ及
びこのセラミックヒータを備えるグロープラグに関す
る。更に詳しくは、特に耐久性に優れるセラミックヒー
タに関する。本発明のセラミックヒータはウォーターヒ
ータ、ディーゼルエンジンのグロープラグ等に利用でき
る。The present invention relates to a ceramic heater and a glow plug provided with the ceramic heater. More specifically, the present invention relates to a ceramic heater having particularly excellent durability. The ceramic heater of the present invention can be used for a water heater, a glow plug of a diesel engine, and the like.
【０００２】[0002]
【従来の技術】従来より、ディーゼルエンジンに使用さ
れるグロープラグを構成するセラミックヒータとして、
炭化タングステン等を主成分とするＵ字状の発熱抵抗体
と、タングステン等を主成分とし、発熱抵抗体の両端部
に接合され、発熱抵抗体に通電するためのリード線と、
からなる導電性部を有するものが多く使用されている。
この導電性部は、更に、窒化珪素等を主成分とする絶縁
性セラミック中に埋設されている。2. Description of the Related Art Conventionally, as a ceramic heater constituting a glow plug used in a diesel engine,
A U-shaped heating resistor mainly composed of tungsten carbide or the like, and a lead wire mainly composed of tungsten or the like and joined to both ends of the heating resistor to supply current to the heating resistor,
Those having a conductive portion made of are often used.
The conductive portion is further embedded in an insulating ceramic mainly containing silicon nitride or the like.
【０００３】このような、絶縁性セラミック中に導電性
部が埋設されたセラミックヒータを製造する場合、リー
ド線を構成する成分と他の成分が焼成時に反応すること
により反応層が形成される。この反応層は十分に緻密化
されていない層であるため機械的強度が不十分であり、
この反応層を基点とするクラック及び折れを生じ易い。
この反応層の形成を抑制することができる技術として、
特開昭６２−７３２号公報、特開平８−３２１３７６号
公報及び特開平１０−２０８８５３号公報等が開示され
ている。When manufacturing such a ceramic heater in which a conductive portion is embedded in an insulating ceramic, a component constituting a lead wire and another component react during firing to form a reaction layer. Since this reaction layer is a layer that is not sufficiently densified, the mechanical strength is insufficient,
Cracks and breaks based on the reaction layer tend to occur.
As a technique that can suppress the formation of this reaction layer,
JP-A-62-732, JP-A-8-321376, and JP-A-10-208853 are disclosed.
【０００４】[0004]
【発明が解決しようとする課題】前記の反応層は、リー
ド線と絶縁性セラミックとの接合性、及びリード線と発
熱抵抗体との接合性を向上させる接合層としての役割も
有している。このため、この反応層が形成されていない
セラミックヒータにおいてはリード線と絶縁性セラミッ
ク等との接合性が低下し易く、セラミックヒータの機械
的強度も十分でなくなることがある。本発明は上記各問
題点を解決するものであり、リード線の接合性は十分に
確保しつつ、セラミックヒータのクラック及び折れの発
生を防止することができるセラミックヒータを提供する
ことを目的とする。更に、このセラミックヒータを用い
た耐久性の高いグロープラグを提供することを目的とす
る。The above-mentioned reaction layer also has a role as a bonding layer for improving the bondability between the lead wire and the insulating ceramic and the bondability between the lead wire and the heating resistor. . For this reason, in a ceramic heater in which the reaction layer is not formed, the bonding property between the lead wire and the insulating ceramic or the like is easily reduced, and the mechanical strength of the ceramic heater may not be sufficient. An object of the present invention is to solve the above-described problems, and an object of the present invention is to provide a ceramic heater that can prevent cracks and breaks in the ceramic heater while sufficiently securing the bonding properties of the lead wires. . Another object of the present invention is to provide a highly durable glow plug using the ceramic heater.
【０００５】[0005]
【課題を解決するための手段】第１発明のセラミックヒ
ータは、発熱抵抗体と該発熱抵抗体に通電するためのリ
ード線とを、絶縁性セラミック中に備えるセラミックヒ
ータにおいて、該リード線と該発熱抵抗体との界面に形
成される接合層の厚さｔと、該接合層の外周面から該絶
縁性セラミックの外周面までの最短距離Ｌとの比は、
０．０００９≦ｔ／Ｌ≦０．０６であることを特徴とす
る。According to a first aspect of the present invention, there is provided a ceramic heater including a heating resistor and a lead wire for supplying a current to the heating resistor in an insulating ceramic. The ratio of the thickness t of the bonding layer formed at the interface with the heating resistor to the shortest distance L from the outer peripheral surface of the bonding layer to the outer peripheral surface of the insulating ceramic is:
0.0009 ≦ t / L ≦ 0.06.
【０００６】上記「発熱抵抗体」を構成する成分は特に
限定されないが、Ｗ、Ｔａ、Ｎｂ、Ｔｉ、Ｍｏ、Ｚｒ、
Ｈｆ、Ｖ及びＣｒから選ばれる金属元素の珪化物、炭化
物及び窒化物うちの少なくとも一種を主成分とすること
が好ましい。中でもＷＣ、ＴｉＮ、ＭｏＳｉ2のうちの
少なくとも一種を主成分とすることがより好ましい。こ
の他、上記各金属元素の硼化物等が含有されてもよい。The components constituting the above-mentioned "heating resistor" are not particularly limited, but include W, Ta, Nb, Ti, Mo, Zr,
It is preferable that at least one of silicides, carbides and nitrides of a metal element selected from Hf, V and Cr is used as a main component. Above all, it is more preferable that at least one of WC, TiN, and MoSi 2 be the main component. In addition, borides of the above-mentioned respective metal elements may be contained.
【０００７】上記「リード線」を構成する成分は特に限
定されないが、Ｗ、Ｒｅ、Ｔａ、Ｍｏ及びＮｂから選ば
れる金属のうちの少なくとも一種を主成分とすることが
好ましい。中でもＷを主成分とすることがより好まし
い。[0007] The components constituting the above "lead wire" are not particularly limited, but it is preferable that at least one metal selected from W, Re, Ta, Mo and Nb is the main component. Above all, it is more preferable that W is a main component.
【０００８】上記「絶縁性セラミック」を構成する成分
は特に限定されないが、窒化珪素、サイアロン及び窒化
アルミニウムのうちの少なくとも一種を主成分とするこ
とが好ましい。また、窒化珪素のみから構成されてもよ
く、発熱抵抗体を構成する各金属元素の硼化物等が含有
されてもよい。The components constituting the above-mentioned "insulating ceramic" are not particularly limited, but it is preferable that at least one of silicon nitride, sialon and aluminum nitride is a main component. Further, it may be composed only of silicon nitride, and may contain boride of each metal element constituting the heating resistor.
【０００９】上記「接合層」は、リード線を構成する成
分が焼成時（特に、ホットプレス焼成時）に他の成分と
反応することにより形成される。他の成分としては、種
々のものが有ると考えられるが、例えば、発熱抵抗体を
構成する成分、絶縁性セラミックを構成する成分、及び
ホットプレス時に使用するカーボン型に含まれる成分、
製造時に使用するバインダに含まれる成分等を挙げるこ
とができる。尚、通常、この接合層はリード線の外周面
を覆うように形成される。The above "joining layer" is formed by reacting a component constituting a lead wire with another component during firing (particularly, during hot press firing). It is thought that there are various other components, for example, components constituting the heating resistor, components constituting the insulating ceramic, and components contained in the carbon mold used at the time of hot pressing,
Examples include components contained in a binder used during production. Usually, this bonding layer is formed so as to cover the outer peripheral surface of the lead wire.
【００１０】上記「ｔ／Ｌ」は０．０００９〜０．０６
（好ましくは０．０００９〜０．０５６、より好ましく
は０．０００９〜０．０５、更には０．００１〜０．０
５）であるとよい。このｔ／Ｌが０．０００９未満であ
るとリード線と絶縁性セラミックとの接着性、及びリー
ド線と発熱抵抗体との接着性が低下し易く、これらの部
材間に隙間を生じることがありセラミックヒータの機械
的強度が低下し易い。一方、ｔ／Ｌが０．０６を越える
と冷熱間サイクル時の、接合層と、リード線、発熱抵抗
体及び絶縁性セラミックとの熱膨張差によりクラック及
び折れを生じ易くなる。尚、ｔは、通常、リード線の外
周面から絶縁性セラミックの外周面までの距離が最短に
なる部位において計測した厚さであるものとする。The above "t / L" is 0.0009 to 0.06.
(Preferably 0.0009 to 0.056, more preferably 0.0009 to 0.05, and even more preferably 0.001 to 0.0
5). If the t / L is less than 0.0009, the adhesiveness between the lead wire and the insulating ceramic and the adhesiveness between the lead wire and the heating resistor are likely to be reduced, and a gap may be generated between these members. The mechanical strength of the ceramic heater tends to decrease. On the other hand, if t / L exceeds 0.06, cracks and breaks are liable to occur due to a difference in thermal expansion between the bonding layer and the lead wire, the heating resistor, and the insulating ceramic during a cold / hot cycle. Note that t is a thickness measured at a portion where the distance from the outer peripheral surface of the lead wire to the outer peripheral surface of the insulating ceramic is shortest.
【００１１】更に、このｔ（μｍ）は第２発明のように
１≦ｔ≦６０（より好ましくは５〜５５μｍ、更には１
０〜５０μｍ）であることが好ましい。ｔが１μｍ以下
であるとリード線と絶縁性セラミックとの接着性、及び
リード線と発熱抵抗体との接着性が低下し易く、これら
の部材間に隙間を生じることがありセラミックヒータの
機械的強度が低下し易い。一方、６０μｍを越えると冷
熱サイクル時の、接合層と、リード線、発熱抵抗体及び
絶縁性セラミックとの熱膨張差によりクラック及び折れ
を生じ易くなる。Further, t (μm) should be 1 ≦ t ≦ 60 (more preferably 5 to 55 μm, furthermore 1
0 to 50 μm). When t is 1 μm or less, the adhesiveness between the lead wire and the insulating ceramic and the adhesiveness between the lead wire and the heating resistor are likely to be reduced, and a gap may be formed between these members, and the mechanical property of the ceramic heater may be reduced. Strength tends to decrease. On the other hand, if the thickness exceeds 60 μm, cracks and breaks are likely to occur due to a difference in thermal expansion between the bonding layer and the lead wire, the heating resistor, and the insulating ceramic during a thermal cycle.
【００１２】本発明のセラミックヒータにおいては、２
≦ｔ（μｍ）＜５０（より好ましくは３≦ｔ（μｍ）＜
５０、更には５≦ｔ（μｍ）＜５０）であればＬの大き
さは７００μｍ以上の範囲において所望の値とすること
が可能となる。また、この場合１３００℃以上における
１分間隔の冷熱サイクルを１万回繰り返した後にも、１
０００ＭＰａ以上（更には１１００ＭＰａ以上、特に１
２００ＭＰａ以上）の高い曲げ強さを保持することがで
きる。更に、ｔが１０≦ｔ（μｍ）＜５０（より好まし
くは２０≦ｔ（μｍ）＜５０、更には３０≦ｔ（μｍ）
＜５０）であればＬの大きさは７００μｍ以上の範囲に
おいて所望の値とすることができ、且つ同様な冷熱サイ
クル後にも１２００ＭＰａ以上（更には１２５０ＭＰａ
以上、特に１３００ＭＰａ以上）の高い曲げ強さを保持
することができる。In the ceramic heater of the present invention, 2
≦ t (μm) <50 (more preferably 3 ≦ t (μm) <
50, and furthermore, if 5 ≦ t (μm) <50), the magnitude of L can be set to a desired value in a range of 700 μm or more. Also, in this case, even after repeating the cooling / heating cycle at 1300 ° C. or more at 1 minute intervals 10,000 times,
000 MPa or more (further 1100 MPa or more, especially 1
(200 MPa or more). Further, t is 10 ≦ t (μm) <50 (more preferably, 20 ≦ t (μm) <50, furthermore, 30 ≦ t (μm)).
If <50), the magnitude of L can be set to a desired value in a range of 700 μm or more, and 1200 MPa or more (further 1250 MPa) even after a similar cooling / heating cycle.
As described above, a high bending strength of 1300 MPa or more can be maintained.
【００１３】ｔが５０≦ｔ（μｍ）≦６０である場合、
Ｌは８５０μｍ以上（より好ましくは９００μｍ以上、
更には１０００μｍ以上）とすることで１０００ＭＰａ
以上の高い曲げ強さを保持することができる。更に、５
０≦ｔ（μｍ）≦５５であれば、Ｌを８５０μｍ以上
（より好ましくは９００μｍ以上、更には１０００μｍ
以上）とすることで１２００ＭＰａ以上の高い曲げ強さ
を保持することができる。このような冷熱サイクル後に
も高い曲げ強さを保持することができるセラミックヒー
タは、更なる冷熱サイクルに対しても高い耐久性を有
し、使用中のクラック及び折れを防止することができ
る。When t is 50 ≦ t (μm) ≦ 60,
L is 850 μm or more (more preferably 900 μm or more,
Further, it is 1000 MPa
The above high bending strength can be maintained. Furthermore, 5
If 0 ≦ t (μm) ≦ 55, L is 850 μm or more (more preferably 900 μm or more, and further 1000 μm
Above), a high bending strength of 1200 MPa or more can be maintained. A ceramic heater that can maintain a high bending strength even after such a cooling / heating cycle has high durability against a further cooling / heating cycle, and can prevent cracks and breaks during use.
【００１４】第３発明のグロープラグは、第１発明又は
第２発明のセラミックヒータを備えることを特徴とす
る。本発明のグロープラグの一例を、縦断面図として図
３に示す。グロープラグ１は、セラミックヒータ２、こ
のセラミックヒータ２を保持するセラミックヒータ保持
具３、このセラミックヒータ保持具３を更に保持する主
体金具４、主体金具４に絶縁保持される電極５と、を備
える。セラミックヒータを構成する発熱抵抗体２１に接
続されたリード線２３ａはコイル状リード線６ａ、セラ
ミックヒータ保持具３、及び主体金具４を介して外部に
接続される。また、リード線２３ｂはコイル状リード線
６ｂを介して頭部が螺子状に成形された電極５に接続さ
れる。このグロープラグは主体金具４に形成された螺子
部により、セラミックヒータの先端部が内燃機関内に突
出するように配設される。[0014] A glow plug according to a third aspect of the present invention is provided with the ceramic heater according to the first or second aspect. One example of the glow plug of the present invention is shown in FIG. 3 as a longitudinal sectional view. The glow plug 1 includes a ceramic heater 2, a ceramic heater holder 3 that holds the ceramic heater 2, a metal shell 4 that further holds the ceramic heater holder 3, and an electrode 5 that is insulated and held by the metal shell 4. . The lead wire 23a connected to the heating resistor 21 constituting the ceramic heater is connected to the outside via the coiled lead wire 6a, the ceramic heater holder 3, and the metal shell 4. Further, the lead wire 23b is connected to the electrode 5 whose head is formed in a screw shape via the coil-shaped lead wire 6b. The glow plug is disposed so that the tip of the ceramic heater projects into the internal combustion engine by a screw formed in the metal shell 4.
【００１５】[0015]
【発明の実施の形態】以下、本発明のセラミックヒータ
を実施例により更に詳しく説明する。 （１）セラミックヒータの作製 焼結助剤として希土類酸化物を２〜５モル％含有し、窒
化珪素中に含まれる不可避酸素及び焼成時に焼結助剤し
て寄与する酸化物をＳｉＯ2換算で２〜１５モル％含有
し、残部がＳｉ3Ｎ4からなる窒化珪素原料粉末と、炭化
タングステン粉末とを体積比で７５：２５となるように
秤量し、この混合粉末を７２時間湿式混合した後、乾燥
し、発熱抵抗体原料粉末を得た。その後、この発熱抵抗
体原料粉末とバインダー（ワックス系バインダ及びポリ
プロピレン）とを混練機に投入し、４時間混練した。次
いで、得られた混練物を裁断してペレット状とし、これ
を射出成型機に投入してタングステン製のリード線が両
端に嵌合されたＵ字状のヒータ成形体を得た。DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the ceramic heater of the present invention will be described in more detail with reference to embodiments. (1) Manufacture of ceramic heater Rare earth oxide is contained as a sintering aid in an amount of 2 to 5 mol%, and unavoidable oxygen contained in silicon nitride and oxides which contribute as a sintering aid during firing are converted into SiO 2 . A silicon nitride raw material powder containing 2 to 15 mol%, the balance being Si 3 N 4, and tungsten carbide powder were weighed so as to have a volume ratio of 75:25, and the mixed powder was wet-mixed for 72 hours. , And dried to obtain a heating resistor raw material powder. Thereafter, the heating resistor raw material powder and a binder (wax binder and polypropylene) were charged into a kneader and kneaded for 4 hours. Next, the obtained kneaded material was cut into pellets, which were put into an injection molding machine to obtain a U-shaped heater molded body in which tungsten lead wires were fitted at both ends.
【００１６】焼結助剤として希土類酸化物を２〜５モル
％含有し、窒化珪素中に含まれる不可避酸素及び焼成時
に焼結助剤して寄与する酸化物をＳｉＯ2換算で２〜１
５モル％含有し、残部がＳｉ3Ｎ4からなるように各粉末
を秤量した。この粉末を４０時間湿式混合した混合粉末
をスプレードライヤー法によって造粒し、この造粒物を
圧粉した２個の半割型を用意した。その後、Ｕ字状のヒ
ータ成形体を２個の半割型の間の所定位置に載置し、プ
レス成形して埋入した後、これらを７０気圧の圧力で一
体に加圧し、未焼成のセラミックヒータを得た。次い
で、この未焼成のセラミックヒータを６００℃で仮焼し
てバインダーを除去し、仮焼体を得た。その後、この仮
焼体をホットプレス用カーボン型にセットし、窒素雰囲
気下、３０００ＭＰａでホットプレス焼成し、セラミッ
クヒータを得た。A rare earth oxide is contained as a sintering aid in an amount of 2 to 5 mol%, and unavoidable oxygen contained in silicon nitride and an oxide which contributes as a sintering aid during firing are 2 to 1 in terms of SiO 2.
Each powder was weighed so that it contained 5 mol% and the balance consisted of Si 3 N 4 . A mixed powder obtained by wet mixing this powder for 40 hours was granulated by a spray drier method, and two half molds obtained by pressing the granulated material were prepared. Thereafter, the U-shaped heater molded body was placed at a predetermined position between the two half molds, press-molded and embedded, and then pressurized integrally at a pressure of 70 atm. A ceramic heater was obtained. Next, the unfired ceramic heater was calcined at 600 ° C. to remove the binder, and a calcined body was obtained. Thereafter, the calcined body was set in a carbon mold for hot pressing and fired in a nitrogen atmosphere by hot press at 3000 MPa to obtain a ceramic heater.
【００１７】（２）接合層の厚さｔの測定 （１）で得られたセラミックヒータを、リード線と発熱
抵抗体の接合部分（先端より２６ｍｍの位置）において
切断し、その断面に現れるｔを拡大撮影し、得られた写
真より測定した。この結果を表１に併記する。(2) Measurement of thickness t of bonding layer The ceramic heater obtained in (1) is cut at the bonding portion (at a position 26 mm from the tip) of the lead wire and the heating resistor, and t appears on the cross section thereof. Was magnified and measured from the obtained photograph. The results are also shown in Table 1.
【００１８】[0018]
【表１】 [Table 1]
【００１９】（３）断続通電による耐久性評価 （１）で得られたセラミックヒータのリード線に電圧を
印加し、セラミックヒータの先端から２ｍｍの位置の温
度を１４００℃に昇温させた。この通電を１分間行いそ
の後１分間通電を中止し、これを１サイクルとして、各
セラミックヒータについて１００００サイクル行うこと
により耐久性を評価した。この結果を表１に示す。表１
にはセラミックヒータが折れるか、又は通電が行えなく
なった時点でのサイクル数を記した。○は１００００サ
イクルの断続通電を行った後にも使用可能であるセラミ
ックヒータを表す。尚、実験例３は、２０００サイクル
で、リード線と発熱抵抗体の接合部を起点に割れが生じ
た。また、実験例８は、５０００サイクルでリード線が
断線したために通電不能となった。(3) Evaluation of durability by intermittent energization A voltage was applied to the lead wire of the ceramic heater obtained in (1), and the temperature at a position 2 mm from the tip of the ceramic heater was raised to 1400 ° C. This energization was performed for 1 minute, and then the energization was stopped for 1 minute, and this was defined as one cycle, and the durability was evaluated by performing 10,000 cycles for each ceramic heater. Table 1 shows the results. Table 1
Indicates the number of cycles at the time when the ceramic heater is broken or the current cannot be supplied. ○ indicates a ceramic heater that can be used even after 10,000 cycles of intermittent energization. In Experimental Example 3, cracks occurred in 2000 cycles starting from the joint between the lead wire and the heating resistor. In Experimental Example 8, the lead wire was disconnected at 5000 cycles, and thus the current could not be supplied.
【００２０】この結果より、ｔ／Ｌが０．０６２５と大
き過ぎる実験例３では２０００サイクル目でセラミック
ヒータに折れが生じた。また、接合層の形成が少ない実
験例８では、５０００サイクル目でセラミックヒータへ
の通電ができなくなった。これに対して、本発明の範囲
内である実験例１、２、４、５、６、１０及び１１では
１００００サイクル後も問題なく使用できる状態であっ
た。From these results, in the experimental example 3 in which t / L was too large as 0.0625, the ceramic heater was broken at the 2000th cycle. In Experimental Example 8 in which the formation of the bonding layer was small, it was impossible to supply power to the ceramic heater at the 5000th cycle. On the other hand, in Experimental Examples 1, 2, 4, 5, 6, 10, and 11, which are within the scope of the present invention, they could be used without any problem even after 10,000 cycles.
【００２１】（４）耐久試験後の曲げ強さの評価 （３）の耐久試験後にＪＩＳ Ｒ １６０１に準じてセ
ラミックヒータの曲げ強さを測定した（３点曲げ、スパ
ン；１２ｍｍ、クロスヘッド速度；０．５ｍｍ／分）。
この結果を表１に併記する。(4) Evaluation of bending strength after durability test After the durability test of (3), the bending strength of the ceramic heater was measured according to JIS R 1601 (three-point bending, span: 12 mm, crosshead speed; 0.5 mm / min).
The results are also shown in Table 1.
【００２２】この結果より、本発明品である実験例１、
２、４、５、６、１０及び１１では（３）の耐久試験後
であっても曲げ強さは１０００〜１３００ＭＰａを保持
しており、十分な機械的強度を有する。特に、ｔが１０
μｍで有れば、Ｌを８００〜１２００μｍとすること
で、耐久試験後であっても１２００〜１３００ＭＰａの
曲げ強さを保持することができる。また、ｔが５０μｍ
と厚い場合であってもＬを１０００〜１２００μｍ（ｔ
／Ｌを０．０４１７〜０．０５）とすることにより１２
００〜１２５０ＭＰａの高い曲げ強さを保持することが
できる。From these results, it can be seen that Experimental Example 1, which is a product of the present invention,
In 2, 4, 5, 6, 10 and 11, even after the endurance test of (3), the flexural strength maintained 1000 to 1300 MPa and had sufficient mechanical strength. In particular, t is 10
If it is μm, by setting L to 800 to 1200 μm, the bending strength of 1200 to 1300 MPa can be maintained even after the durability test. Also, t is 50 μm
L is 1000 to 1200 μm (t
/ L is set to 0.0417 to 0.05).
A high bending strength of 00 to 1250 MPa can be maintained.
【００２３】接合層が形成されていないセラミックヒー
タである実験例７及び９では、耐久試験では１００００
サイクルの耐久には耐えられたものの、本発明品と比べ
るとその後の曲げ強さは２００〜３００ＭＰａと極めて
小さくなっていることが分かる。また、実験例８では通
電中に折れは生じなかったが、その後の曲げ強さは１０
０ＭＰａと非常に小さかった。In Experimental Examples 7 and 9, which are ceramic heaters having no bonding layer formed, the durability test was 10,000
It can be seen that, despite the durability of the cycle, the bending strength after that was extremely small, 200 to 300 MPa, as compared with the product of the present invention. In Experimental Example 8, no break occurred during energization, but the bending strength after that was 10%.
It was very small at 0 MPa.
【００２４】尚、本発明においては、これらの実施例に
限られず、目的、用途に応じて本発明の範囲内で種々変
更した実施例とすることができる。即ち、発熱抵抗体の
原料粉末として、窒化珪素質粉末８５．５〜９２．５重
量部、Ｅｒ2Ｏ3６〜１０重量部、及び焼結助剤としてＷ
Ｏ3１〜３重量部を混合した粉末３５〜５５重量％とＷ
Ｃ粉末４５〜６５重量％とを混合して使用することもで
きる。また、Ｅｒ2Ｏ3の代わりにＹ2Ｏ3及び／又はＹｂ
2Ｏ3を用いてもよく、更に、ＷＯ3の代わりにＡｌ2Ｏ3
及び／又はＳｉＯ2を用いてもよい。この他、仮焼の温
度は６００〜８００℃とすることができ、焼成の雰囲気
は不活性ガス等、窒素以外の不活性な雰囲気、及び真空
等の雰囲気とすることもできる。It should be noted that the present invention is not limited to these embodiments, but can be variously modified within the scope of the present invention according to the purpose and application. Ie, W as the raw material powder of the heat-generating resistor, siliceous nitride powder from 85.5 to 92.5 parts by weight, Er 2 O 3 6 to 10 parts by weight, and as a sintering aid
35 to 55% by weight of powder mixed with 1 to 3 parts by weight of O 3 and W
It is also possible to use a mixture of 45 to 65% by weight of C powder. Also, instead of Er 2 O 3 , Y 2 O 3 and / or Yb
2 O 3 may be used. Further, instead of WO 3 , Al 2 O 3
And / or SiO 2 may be used. In addition, the calcination temperature can be set to 600 to 800 ° C., and the calcination atmosphere can be an inert atmosphere other than nitrogen, such as an inert gas, or an atmosphere such as a vacuum.
【００２５】[0025]
【発明の効果】第１発明によれば、冷熱間サイクルに対
する耐久性が高く、機械的強度が高いセラミックヒータ
を得ることができる。特に、第２発明によると、更に冷
熱間サイクルに対する耐久性が高く、機械的強度が高い
セラミックヒータを得ることができる。第３発明による
と、冷熱間サイクルに対する耐久性が高いグロープラグ
を得ることができる。According to the first invention, a ceramic heater having high durability against cold and hot cycles and high mechanical strength can be obtained. In particular, according to the second invention, it is possible to obtain a ceramic heater having higher durability against a cold / hot cycle and higher mechanical strength. According to the third invention, it is possible to obtain a glow plug having high durability against a cold / hot cycle.
【図１】本発明のセラミックヒータの一例であり、図２
におけるＸ−Ｘ’における横断面を示す模式図である。FIG. 1 is an example of a ceramic heater of the present invention, and FIG.
FIG. 3 is a schematic view showing a cross section taken along line XX ′ of FIG.
【図２】本発明のセラミックヒータの一例の縦断面を示
す模式図である。FIG. 2 is a schematic diagram showing a longitudinal section of an example of the ceramic heater of the present invention.
【図３】本発明のグロープラグの一例の縦断面を示す模
式図である。FIG. 3 is a schematic view showing a longitudinal section of an example of the glow plug of the present invention.
【符号の説明】 １；グロープラグ、２；セラミックヒータ、２１、発熱
抵抗体、２２、絶縁性セラミック、２３ａ、２３ｂ；リ
ード線、２４、接合層、３；セラミックヒータ保持具、
４；主体金具、５；プラグ電極、６ａ、６ｂ；コイル状
リード線DESCRIPTION OF SYMBOLS 1; glow plug, 2; ceramic heater, 21, heating resistor, 22, insulating ceramic, 23a, 23b; lead wire, 24, bonding layer, 3: ceramic heater holder,
4; metal shell; 5; plug electrode; 6a, 6b; coiled lead wire
Claims (3)
めのリード線とを、絶縁性セラミック中に備えるセラミ
ックヒータにおいて、該リード線と該発熱抵抗体との界
面に形成される接合層の厚さｔと、該接合層の外周面か
ら該絶縁性セラミックの外周面までの最短距離Ｌとの比
は、０．０００９≦ｔ／Ｌ≦０．０６であることを特徴
とするセラミックヒータ。1. A bonding layer formed at an interface between a lead wire and a heating resistor in a ceramic heater including a heating resistor and a lead wire for supplying electricity to the heating resistor in an insulating ceramic. The ratio of the thickness t to the shortest distance L from the outer peripheral surface of the bonding layer to the outer peripheral surface of the insulating ceramic is 0.0009 ≦ t / L ≦ 0.06. .
ある請求項１記載のセラミックヒータ。2. The ceramic heater according to claim 1, wherein the thickness t (μm) satisfies 1 ≦ t ≦ 60.
を備えることを特徴とするグロープラグ。3. A glow plug comprising the ceramic heater according to claim 1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30894499A JP3874581B2 (en) | 1999-10-29 | 1999-10-29 | Ceramic heater and glow plug using the same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30894499A JP3874581B2 (en) | 1999-10-29 | 1999-10-29 | Ceramic heater and glow plug using the same |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2001132950A true JP2001132950A (en) | 2001-05-18 |
| JP3874581B2 JP3874581B2 (en) | 2007-01-31 |
Family
ID=17987146
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP30894499A Expired - Lifetime JP3874581B2 (en) | 1999-10-29 | 1999-10-29 | Ceramic heater and glow plug using the same |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20100288747A1 (en) * | 2007-10-29 | 2010-11-18 | Kyocera Corporation | Ceramic heater and glow plug provided therewith |
| US20110114622A1 (en) * | 2008-02-20 | 2011-05-19 | Ngk Spark Plug Co., Ltd. | Ceramic heater and glow plug |
-
1999
- 1999-10-29 JP JP30894499A patent/JP3874581B2/en not_active Expired - Lifetime
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20100288747A1 (en) * | 2007-10-29 | 2010-11-18 | Kyocera Corporation | Ceramic heater and glow plug provided therewith |
| US20110114622A1 (en) * | 2008-02-20 | 2011-05-19 | Ngk Spark Plug Co., Ltd. | Ceramic heater and glow plug |
| US8378273B2 (en) * | 2008-02-20 | 2013-02-19 | Ngk Spark Plug Co., Ltd. | Ceramic heater and glow plug |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3874581B2 (en) | 2007-01-31 |
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