Abstract: An object is to meet the demands for increasing the number of teeth of a rotor in an internal gear pump while maintaining a theoretical discharge amount by using an equivalent body configuration so as to enhance the pump performance relating to discharge pulsation due to the increased number of teeth. In a pump rotor 1 formed by combining of an inner rotor (2) having N teeth and an outer rotor (3) having (N+1) teeth and disposing the rotors eccentrically relative to each other, the relational expression ?Dmax<1.7e·sin(?/180)/sin {?/(180·N)} is satisfied, ?Dmax being a maximum value of a working pitch diameter of the inner rotor (2) and the outer rotor (3), and a working position (G) of the inner rotor (2) and the outer rotor (3) is always located rearward of an eccentric axis (CL) in a rotating direction of the rotor.

Abstract: An internal gear pump includes a pump rotor (4) in which a meshing point between an inner rotor (2) having n teeth and an outer rotor (3) having (n+1) teeth is located rearward, in a rotational direction of the rotor, relative to an eccentric axis (CL) along which a center (OI) of the inner rotor and a center (Oo) of the outer rotor are disposed. A tooth-surface curve of the outer rotor (3) near a meshing section thereof is formed by duplicating thereto a tooth-surface shape of the inner rotor (2) near a meshing section thereof.

Abstract: The present invention relates to a method for molding a powder mold product according to which a powder mold product of uniform quality can be molded with excellent productivity. The present invention includes the steps of: preparing raw material powder 3 (a preparing step); interposing a mold assembly-use lubricant between an outer circumferential face 12s of a first punch (a lower punch 12) and an inner circumferential face 10s of a die 10, the lower punch 12 and the die 10 in this state being relatively shifted to apply the mold assembly-use lubricant to the inner circumferential face 10s of the die 10 (an applying step); and packing the raw material powder 3 into a cavity, a powder mold product 100 being molded by the raw material powder 3 being pressed (a molding step).

Abstract: An internal gear pump includes an inner rotor having n teeth and an outer rotor having (n+1) teeth. A tooth profile of the inner rotor is an envelope of a group of locus circles (13) each having a diameter C and having a center on a trochoidal curve (T), the trochoidal curve being drawn along a locus of a fixation point, which is located distant from a center of a rolling circle (12) by e, when the rolling circle (12) rolls along a base circle (11) without sliding. A tooth profile of the outer rotor is an envelope of a group of tooth-profile curves of a formation inner rotor, the envelope being obtained by first drawing the formation inner rotor in which a diameter of the locus circle (13) is equal to C? determined from expression (C?t), revolving a center (OI) of the formation inner rotor by one lap along a circle (S) having a diameter (2e) and centered on a center (OO) of the outer rotor, and rotating the formation inner rotor 1/n times during the revolution.

Abstract: A compact 10 is obtained by compression-molding coated soft magnetic particles covered with insulating coatings, and is a modified frustum body having, as a main body, a frustum portion 113 sandwiched between plate-shaped portions 111 and 112 arranged in opposing relation. A vertical cross-section of the compact 10 is made up of a trapezoidal surface 113s, a long-side rectangular surface 111s joining to a long side of the trapezoidal surface 113s, and a short-side rectangular surface 112s joining to a short side of the trapezoidal surface 113s.

Abstract: In an internal gear pump 9, a diameter of a base circle is set to A mm, a radius of a rolling circle is set to b mm, a diameter of a locus circle is set to C mm, and an amount of eccentricity is set to e mm. A trochoidal curve T is drawn by rolling the rolling circle along the base circle without slipping and by using a locus of a fixed point distant from a center of the rolling circle by e. A tooth profile of an inner rotor 2 having n teeth is formed based on an envelope of a group of the locus circles each having a center on the trochoidal curve T. A pump rotor 1 is formed by combining the inner rotor with an outer rotor having (n+1) teeth. A tooth-profile curve of the inner rotor satisfies the following expression (1). Because K<1 is satisfied, cusps s are not formed at opposite edges of each addendum of the inner rotor 2.

Abstract: A gear pump rotor is provided including a combination of an inner rotor and an outer rotor whose numbers of teeth are different by one, and the discharge amount of the pump is increased by an increase of the tooth depth. At least one of an addendum curve and a dedendum curve of an inner rotor is formed by a locus of one point on formation circles that satisfy moving conditions that the formation circles move from moving start points to moving end points while changing the distances from an inner rotor center to the centers of the formation circles. The centers of the formation circles move by a distance in the radial direction of a base circle, and the formation circles rotate by an angle at a constant angular velocity in the same directions of the moving directions of the formation circles.

Abstract: A low-loss compact and a method for producing the compact are provided. A method for producing a compact by using coated soft magnetic powder that includes coated soft magnetic particles constituted by soft magnetic particles and insulating coatings coating outer peripheries of the soft magnetic particles includes a raw material preparation step and an irradiation step. In the raw material preparation step, a raw compact is prepared by press-forming coated soft magnetic powder. In the irradiation step, part of a surface of the raw compact is irradiated with a laser. Irradiating a part of a surface of a raw compact with laser increases the number of disrupted portions of conductive portions where constituent materials of the soft magnetic particles at the surface of the raw compact have become conductive to each other, and the loss of the compact can be decreased.

Abstract: When an outer core that is to be mounted on a reactor is seen in plan, the outer core is a compact that has a plan-view shape in which a side of the outer core that is opposite to a facing side of the outer core, which faces the inner cores, has a smaller dimension in a width direction, which is parallel to a facing surface, than the facing side of the outer core. A method of manufacturing such an outer core includes a preparing step and a compacting step. In the preparing step, coated soft magnetic powder including multiple coated soft magnetic particles formed by coating soft magnetic particles with insulating coated films is prepared as raw-material powder of the outer core.

Abstract: Provided are a green compact from which a low-loss core can be formed, a method of manufacturing the green compact, and a core for a reactor using the green compact. Parts of outer circumferential surfaces of green compacts 41 and 42 are molded with an inner peripheral surface of a through hole 10hA of a die 10A, and the other parts are molded with an outer circumferential surface of a core rod 13A that is inserted and disposed in the through hole 10hA. A raw-material powder P, which is a coated soft magnetic powder, is fed into compacting spaces 31 and 32 and pressurized by using a lower punch 12 (first punch) and an upper punch 11 (second punch). Then, the green compacts 41 and 42 are removed from the compacting spaces 31 and 32 by moving the die 10A with respect to the green compacts 41 and 42 without moving the core rod 13A with respect to the green compacts 41 and 42.

Abstract: An object is to meet the demands for increasing the number of teeth of a rotor in an internal gear pump while maintaining a theoretical discharge amount by using an equivalent body configuration so as to enhance the pump performance relating to discharge pulsation due to the increased number of teeth. In a pump rotor 1 formed by combining of an inner rotor (2) having N teeth and an outer rotor (3) having (N+1) teeth and disposing the rotors eccentrically relative to each other, the relational expression ?Dma <1.7e·sin(?/180)/sin {?/(180·N)} is satisfied, ?Dmax being a maximum value of a working pitch diameter of the inner rotor (2) and the outer rotor (3), and a working position (G) of the inner rotor (2) and the outer rotor (3) is always located rearward of an eccentric axis (CL) in a rotating direction of the rotor.

Abstract: Flexibility is given in setting the tooth depth and the number of teeth of a pump rotor including a combination of an inner rotor and an outer rotor whose numbers of teeth are different by one, and the discharge amount of the pump is increased by the increase of the tooth depth. At least one of an addendum curve and a dedendum curve of an inner rotor (2) is formed by a locus of one point (j) on formation circles (B, C) that satisfy moving conditions that the formation circles (B, C) move from moving start points (Spa, Spb) to moving end points (Lpa, Lpb) while changing the distances from an inner rotor center (OI) to the centers of the formation circles, the centers of the formation circles move by a distance (R) in the radial direction of a base circle (A) during this, and the formation circles (B, C) rotate by an angle ? at a constant angular velocity in the same directions of the moving directions of the formation circles.