Hitachi, Ltd.

Motomichi Doi

Katsutoshi Nii

Kinpei Okano

Kazuhiko Kawaike

Masayuki Urashin

Minetoshi Izushi

Minoru Kitsuya

Yoshiharu Yokota

A screw compressor comprises a casing and a pair of male and female rotors respectively having herical teeth and grooves formed in their outer peripheries. The rotors are arranged within the casing in meshing relation to each other through the teeth and grooves. Each rotor is rotatably supported by a pair of first and second radial plain bearings and a thrust plain bearing which is arranged at an end of the rotor shaft and adjacent the second radial plain bearing. Each of the thrust plain bearings is of dynamic-pressure type in which with rotation of a corresponding one of the shafts of the respective rotors, pressure is applied to lubricant by sliding movement of the thrust plain bearing to produce an anti-thrust force. The lubricant for each of the second radial plain bearings and for a corresponding one of the thrust plain bearings is fed to a space between the second radial plain bearing and the thrust plain bearing, and is distributed to the second radial plain bearing more in amount than that fed to the thrust bearing due to a difference between flow resistance with which the lubricant passes through the second radial plain bearing and flow resistance with which the lubricant passes through the thrust plain bearing.

Screw compressor

A method of producing a bearing component such as an inner ring, an outer ring and rolling elements having a solid lubricant on a frictional surface part thereof, which comprises a step of forming a coating of a material on a frictional surface part of a metal substrate, the solubilities of the coating material in the substrate metal and in the solid lubricant being higher than the mutual solubility of the substrate metal and the solid lubricant, a step of providing on a surface part of the coating a solid lubricant consisting of a metallic material having a low solubility in the substrate metal, and a step of maintaining the solid lubricant, the coating and the metal substrate for a predetermined period of time at a predetermined temperature of below the lower one of the maximum operating temperature of the bearing component and the melting point of the solid lubricant so as to induce mutual diffusion between the metal substrate, the coating and the solid lubricant, thereby increasing the bonding strength between them, and a bearing comprising the bearing component produced by the method.

Method of producing bearing component

A rotary anode X-ray tube accommodated in a housing together with oil has a journal box fixed and inwardly extending inside the tube, an anode target fixed to a rotor supported by the journal box and a cathode member opposing the anode target and fixed at an end portion inside the tube opposing the journal box. The fixing portion between the rotary anode X-ray tube and the journal box is supported by a resilient support member on the housing and vibration damping means is disposed on the support member. The vibration damping means includes a moving member fixed at its center and a fixed member fixed to the housing so as to encompass the moving member with a predetermined gap, and oil is fully charged in the gap. Vibration of the rotation system is transmitted to the moving member and the operation of this member damps the vibration by means of the squeeze action of the oil.

X-Ray tube apparatus

Growing community of inventors

Hitachi, Japan

Motomichi Doi