Patent application number | Description | Published |
20080315895 | TEST METHOD AND APPARATUS FOR SPARK PLUG INSULATOR - There is provided a test method for detecting the presence or absence of a defect in a spark plug insulator, including a reference voltage determination process, a test area determination process, a test voltage determination process and a current detection process. In the reference voltage determination process, a reference voltage V | 12-25-2008 |
20120080996 | SPARK PLUG - A task of this invention is to provide a spark plug that is superior in withstand voltage characteristics at high temperatures. A spark plug of this invention is equipped with a center electrode, an insulator, and a metal shell, and is characterized by that the insulator is equipped with an alumina-based sintered body containing silicon component (Si component), magnesium component (Mg component), at least one component of calcium component, strontium component, and barium component, and a rare earth element component (RE component), that a grain boundary phase of the alumina-based sintered body has a hexaaluminate crystal containing the RE component, that, in the alumina-based sintered body, the weight ratio of the RE component to the Mg component is 5.4≦RE oxide/MgO≦17.5, and that the content of an alkali metal component in terms of oxide in a spot having a diameter of 0.3 nm, where the hexaaluminate crystal or the hexaaluminate crystal and Si component in the grain boundary phase is present by TEM, ranges from 0.01 weight % to 20 weight %. | 04-05-2012 |
20120176022 | SPARK PLUG - To provide a spark plug excellent in the acid resistance and high-temperature withstand voltage characteristics. A spark plug | 07-12-2012 |
20120187819 | SPARK PLUG AND PROCESS FOR PRODUCING SPARK PLUG - A spark plug which exhibits high dielectric strength at high temperature and which is unlikely to be deteriorated in dielectric strength is provided. The spark plug includes a center electrode, an insulator, and a metallic shell. The insulator includes an alumina-based sintered body which contains a silicon component, a Group II element component, and a rare earth element component. The alumina-based sintered body is composed of a glass phase and an alumina crystal phase as observed through X-ray diffraction analysis. When the grain boundary phase of the alumina-based sintered body is observed under a transmission electron microscope, and the weight ratio between an alkali metal component and the rare earth element component as reduced to oxides thereof [alkali metal/rare earth element] is calculated at 30 circular spots, each having a diameter of 0.3 nm, selected arbitrarily in a field of observation, the average of the weight ratios of the 30 spots falls within a range of 0.01 to 1.0. | 07-26-2012 |
20120262049 | SPARK PLUG AND PROCESS FOR PRODUCING SPARK PLUG - A spark plug that is equipped with an insulator that has a stem portion on a front end side, a center electrode, and a main metal member that retains the insulator at an engaging projection portion, wherein an inner diameter D | 10-18-2012 |
20120319556 | SPARK PLUG AND METHOD FOR MANUFACTURING SPARK PLUG - The present invention relates to a spark plug having good combustible-gas ignitability even when the spark plug is downsized and to a method for high-yield manufacturing of a spark plug with good combustible-gas ignitability. There is provided according to one aspect of the present invention a spark plug | 12-20-2012 |
20140091707 | IGNITION PLUG - An ignition plug, wherein, when a relative density of a portion of an insulator, which is positioned between a radial virtual plane including a front end of the insulator and a radial virtual plane including a front end of a portion of the insulator which is in contact with a metal shell or the plate packing, is referred to as A (%), and a relative density of a portion of the insulator, which is positioned between the radial virtual plane including the front end of the portion of the insulator which is in contact with the metal shell or the plate packing and a radial virtual plane including a center of a resistor in an axial direction, is referred to as B (%), the following equations are satisfied: 93.90≦A, and 0.10≦A−B≦0.90. | 04-03-2014 |
20150047880 | SPARK PLUG - A spark plug exhibiting excellent withstand voltage characteristics and mechanical strength at high temperature, which are comparable to those at ambient temperature. The spark plug having an insulator formed of an alumina-based sintered material containing: an Al component, an Si component, a Group 2 element component, and a rare earth element component. The amounts of such components satisfy a condition (1): 0.25≦ oxide-reduced amount (mass %) of the Si component ≦1.25, and a condition (2): 1.35≦[(oxide-reduced amount of the Si component)/((oxide-reduced amount of the Group 2 element component)/(oxide-reduced amount of the rare earth element component))]≦7.5. The alumina-based sintered material includes alumina grains, and a glass phase including a crystal phase that satisfies a condition (3) that the crystal phase includes at least one of an aluminate crystal phase and a silicate crystal phase, each having a grain size of 20 to 350 nm. | 02-19-2015 |