Abstract: To lighten the weight of an electromagnetic actuator and a valve-open-close mechanism by forming the stems from a lighter material than conventional. A pair of electromagnets formed of stators and coils are opposed to each other with a gap therebetween. An armature is disposed in the gap so as to be reciprocable between one electromagnet and the other electromagnet by the electromagnets. A first stem for transmitting the movement of the armature from one electromagnet toward the other electromagnet to a valve of the internal combustion engine is inserted in a guide hole formed in the stator of one electromagnet. The first stem is formed of a lighter material than the armature to lighten the weight of the electromagnetic actuator and a valve-open-close mechanism of an internal combustion engine.

Abstract: To lighten the weight of an electromagnetic actuator and a valve-open-close mechanism by forming the stems from a lighter material than conventional. A pair of electromagnets formed of stators and coils are opposed to each other with a gap therebetween. An armature is disposed in the gap so as to be reciprocable between one electromagnet and the other electromagnet by the electromagnets. A first stem for transmitting the movement of the armature from one electromagnet toward the other electromagnet to a valve of the internal combustion engine is inserted in a guide hole formed in the stator of one electromagnet. The first stem is formed of a lighter material than the armature to lighten the weight of the electromagnetic actuator and a valve-open-close mechanism of an internal combustion engine.

Abstract: An electromagnetic actuator for an automotive internal combustion engine is provided which has a stator, the weight of which is reduced. The electromagnetic actuator has a pair of electromagnets each made up of a stator and a coil, an armature disposed between the pair of electromagnets so as to be reciprocable therebetween, and a first stem provided on one side of the armature for transmitting the movement of the armature to external. The stator is formed by powder molding.

Abstract: It is proposed to lessen the weight and improve the mechanical strength of a retainer of a valve open-close mechanism driven by an electromagnetic actuator used in an automotive internal combustion engine. The electromagnetic actuator is mounted in a housing mounted on an internal combustion engine body. A first stem has its tip abutting the valve, which is provided with a retainer and carries a first coil spring. A second stem is provided on the other side of an armature. The second stem has a retainer. Between this retainer and the housing, a second coil spring is mounted. At least one of these parts is made of a metal smaller in specific weight than iron or its alloy. Each retainer has a boss and an arcuate corner portion having a radius of curvature R of 1.0 mm or over between a spring abutting surface and the boss to relieve stress concentration.

Abstract: A valve-open-close mechanism is proposed which has parts designed to reduce friction during sliding. The electromagnetic actuator comprises a pair of electromagnets each having a stator and a coil opposed to each other with a gap therebetween, an armature disposed in the gap, and a first stem for transmitting to external the movement of said armature. A retainer and a first return spring are provided on the valve. A second stem is provided at other side of the armature and another retainer and a second return spring are provided for the second stem. A coating film is formed on at least one of the surface or end face of the stem portion of the valve, end faces of the first return spring or second return spring, spring bearing end faces of the retainers, surface or end face of the second stem, and the surface of the armature.

Abstract: An electromagnetic actuator for an automotive internal combustion engine is provided which has a stator, the weight of which is reduced. The electromagnetic actuator has a pair of electromagnets each made up of a stator and a coil, an armature disposed between the pair of electromagnets so as to be reciprocable therebetween, and a first stem provided on one side of the armature for transmitting the movement of the armature to external. The stator is formed by powder molding.

Abstract: It is proposed to lessen the weight and improve the mechanical strength of a retainer of a valve open-close mechanism driven by an electromagnetic actuator used in an automotive internal combustion engine. The electromagnetic actuator is mounted in a housing mounted on an internal combustion engine body. A first stem has its tip abutting the valve, which is provided with a retainer and carries a first coil spring. A second stem is provided on the other side of an armature. The second stem has a retainer. Between this retainer and the housing, a second coil spring is mounted. At least one of these parts is made of a metal smaller in specific weight than iron or its alloy. Each retainer has a boss and an arcuate corner portion having a radius of curvature R of 1.0 mm or over between a spring abutting surface and the boss to relieve stress concentration.

Abstract: A valve-open-close mechanism is proposed which has parts designed to reduce friction during sliding. The electromagnetic actuator comprises a pair of electromagnets each having a stator and a coil opposed to each other with a gap therebetween, an armature disposed in the gap, and a first stem for transmitting to external the movement of said armature. A retainer and a first return spring are provided on the valve. A second stem is provided at other side of the armature and another retainer and a second return spring are provided for the second stem. A coating film is formed on at least one of the surface or end face of the stem portion of the valve, end faces of the first return spring or second return spring, spring bearing end faces of the retainers, surface or end face of the second stem, and the surface of the armature.

Abstract: An exhaust gas purifier, having three or more filter units parallel, wherein if at least one filter unit fails during its generation, it is compensated by the cyclic operation of the maining filter units so that the total function of the exhaust gas purifier is practically maintained. Electric heaters 14 are provided for regenerating individual filter units 3, and valves 4 are placed either at the entrances or at the exits of the units 3. While filter units 3 with opened valves 4 trap particulates, at least one filter unit 3's valve 4 is closed to send an electric current into the heater 14 for regenerating the filter unit 3. If the detected current is beyond a predetermined range, the current supply is shut off with the valve 4 still kept closed, and another filter unit 3 is regenerated in the same manner.

Abstract: An object is to provide a particulate trap for a diesel engine which can efficiently burn particulates trapped by a filter while supplying oxygen by natural convection so that the filter can be regenerated in a short time while minimizing the power consumed by the heater. To accomplish this purpose, end plates 6, 7 and brackets 9 may be welded to compressed portions 4a, 5a of an inner cylinder 4 and an outer cylinder 5; heater-supporting ceramic insulators are mounted, spaced from each other, on a heater 14; and/or an ambient air introducing passage 36 is provided to extend from outside the case into a multiple-cylinder filter provided in the case.

Abstract: A particulate trap which can be used in a medium- or small-sized diesel engine car includes concentrically arranged cylindrical filters made of a three-dimensionally reticulated metallic porous material and a plate-shaped electric heater for regeneration having an output of 400 W or less, and is provided between the filters and spaced therefrom. The filters have a relatively shortened length. The heating amount of the filters by the heater is 0.60 W/cm.sup.2 or more. The filter has an increased thickness to make up for reduction in the filter surface area due to the shortened filter length. With this arrangement, it is possible to achieve a high regeneration efficiency with a low-output heater while suppressing heat loss.

Abstract: A slide member has a sliding surface made of ceramic and a has surface roughness of not more than 1.0 .mu.m in center line average roughness Ra. The ceramics includes a silicon nitride sintered body which contains crystal grains having a linear density of at least 35 per 30 .mu.m in length with a boundary phase volume ratio of not more than 15 volume %, and which contains pores of not more than 20 .mu.m in maximum diameter in a content of not more than 3%. In a method of manufacturing the slide member, it is possible to ensure smoothness of the sliding surface by grinding the sliding surface and thereafter heating the ceramic in an either an inert gas or atmospheric air. A slide member that can be used under severe sliding conditions of high-speed sliding or the like and that has excellent wear resistance is obtained.

Abstract: A composite bearing structure that has a high rotational accuracy and that can withstand high-speed rotation comprises first bearing means, second bearing means, third bearing means and fourth bearing means. The first bearing means supports a radial impact force which is applied to a rotator during rotation, and is formed by an inner ring (1) and an outer ring (2) consisting of silicon nitride ceramics sintered bodies. The second bearing means supports an axial load which is applied to the rotator while maintaining a prescribed clearance with the rotator, and is formed by a magnetic bearing body of two permanent magnets (12) and (13) which are thrust-directionally opposed to each other. The third bearing means maintains the radial rotational accuracy of the rotator, and is formed by a radial dynamic pressure producing groove (5) which is formed in a cylindrical surface of the inner ring (1).

Abstract: A combination of an adjusting shim and a cam used in a valve train in an internal combustion engine for automobiles, the adjusting shim composed of a ceramic material which sets the surface roughness of a sliding surface of the adjusting shim with respect to a cam to not more than 0.1 .mu.m in ten-point mean roughness Rz, and which contains not less than 60 vol. % of silicon nitride or sialon, and the cam composed of cast iron a surface of which is chill hardened and then provided with a phosphate film thereon. The combination of an adjusting shim and a cam is capable of smoothing a sliding surface of the cam by the break-in of the part even if the cam is not subjected to a super-precision finishing process; preventing the seizure and abnormal abrasion of sliding surfaces; stabilizing a smoothed condition of the sliding surfaces of the cam and shim for a long period of time; and providing excellent sliding characteristics of the sliding surfaces owing to a decrease in the friction coefficient thereof.

Abstract: An industrially feasible method of grinding silicon nitride ceramics is disclosed and provides a sufficiently smooth surface. Namely, the surface has a maximum height-roughness Rmax of 0.1 microns or less and a ten-point mean roughness Rz of 0.05 micron. Further, with this method, surface damage can be repaired while grinding. The vertical cutting feed rate of a grinding wheel into a workpiece should be within the range of 0.005-0.1 micron for each rotation of the working surface of the wheel and change linearly or stepwise. The cutting speed of the grinding wheel in a horizontal (rotational) direction should be within the range of 25 to 75 m/sec. With this arrangement, the contact pressure and grinding heat that is generated between the workpiece and the hard abrasive grains during grinding are combined. In other words, mechanical and thermal actions are combined.

Abstract: An industrially feasible method of grinding silicon nitride ceramics is disclosed and provides a sufficiently smooth surface. Namely, the surface has a maximum height-roughness Rmax of 0.1 microns or less and a ten-point mean roughness Rz of 0.05 microns. Further, with this method, surface damage can be repaired while grinding. The vertical cutting feed rate of a grinding wheel into a work piece should be within the range of 0.005-0.1 micron for each rotation of the working surface of the wheel and change linearly or stepwise. The cutting speed of the grinding wheel in a horizontal (rotational) direction should be within the range of 25 to 75 m/sec. With this arrangement, the contact pressure and grinding heat that is generated between the work piece and the hard abrasive grains during grinding are combined. In other words, mechanical and thermal actions are combined.

Abstract: A slide member has a sliding surface made of ceramic and has a surface roughness of not more than 1.0 .mu.m in center line average roughness Ra. ceramic includes a silicon nitride sintered body, which contains crystal grains having a linear density of at least 35 per 30 .mu.m in length with a boundary phase volume ratio of not more than 15 volume %, and which contains pores of not more than 20 .mu.m in maximum diameter in a content of not more than 3%. In a method of manufacturing the slide member, it is possible to ensure smoothness of the sliding surface by grinding the sliding surface and thereafter heating the ceramic in either inert gas or an atmospheric air. A slide member that can be used under severe sliding conditions of high-speed sliding or the like and that has excellent wear resistance is obtained.

Abstract: A silicon nitride sintered body characterized by comprising crystal grains having a linear density of 60 to 120 per 50 .mu.m length as measured in an arbitrary two-dimensional section of the sintered body. The silicon nitride sintered body has a shock compressive elasticity limit (Hugoniot-elastic limit) of 15 GPa or more and is substantially composed of crystal phases of .alpha.-silicon nitride and .beta.'-sialon. The percentages of the .alpha.-silicon nitride and .beta.'-sialon are not more than 30% and not less than 70%, respectively. The silicon nitride sintered body is particularly excellent in mechanical strengths at room temperature as well as in productivity and cost efficiency and is useful for applications as the material of parts where a particularly high impact strength is required, such as a valve train mechanism for automobile parts.

Abstract: The preset invention provides a ceramic adjusting shim capable of minimizing the abrasion of parts contacting the adjusting shim, for example, a cam and a tappet. The ceramic adjusting shim is produced from a ceramic material and has a surface roughness of 0.05 to 0.2 .mu.m in ten-point average roughness Rz.

Abstract: The present invention provides an improved adjusting shim used in a valve train for an internal combustion engine for an automobile. The adjusting shim produced from a base material consisting of a ceramic material containing 80 to 98 wt. % of silicon nitride and/or sialon and has a porosity of not more than 3%, a bending strength of not less than 1.0 GPa and an impact compressive elastic limit (Hugoniot elastic limit) of not less than 15 GPa, wherein the base material is provided on the surface thereof which contacts a cam with a ceramic surface layer having a composition different from that of the base material and a hardness lower than that of the base material. The adjusting shim of the present invention enables a power loss of a valve train to be minimized; the abrasion resistance thereof to be improved; and the fuel economy, the performance and durability of an internal combustion engine to be improved.