# US 5,346,316 A · Bearing unit, drainage pump and hydraulic turbine each incorporating the bearing unit > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,346,316 A - Document ID: US5346316A - Status: Granted - Kind: A - Application number: 08/034,379 - Filed: 1993-03-18 - Granted: 1994-09-13 - Earliest claimed: 1992-03-18 - Assignees: Hitachi, Ltd. - Inventors: Ryoji Okada; Kooju Aizawa; Masayuki Yamada; Kenji Otani; Kunio Takada; Mitsuaki Haneda; Toshihiro Yamada - Web page: https://patentgrep.com/patent/US5346316A ## CPC - F04D 29/047: hydrostatic; hydrodynamic - C23C 4/06: Metallic material - F04D 29/0465: {Ceramic bearing designs} - F16C 33/12: Structural composition; Use of special materials or surface treatments, e.g. for rust-proofing - F16C 33/122: {Multilayer structures of sleeves, washers or liners} - F04D: NON-POSITIVE-DISPLACEMENT PUMPS (engine fuel-injection pumps F02M; ion pumps H01J41/12; electrodynamic pumps H02K44/02) - C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04) - F16C: SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS ## Abstract Disclosed is a bearing unit which can be used in a drainage pump operated without supply of clean water or a hydraulic pump, which exhibits excellent wear resistance against water containing earth and sand and satisfactory assembling facility, and a method of manufacturing the bearing unit. The contact surface of a bearing made of stainless steel and/or that of a sleeve is applied with a sprayed coating, the main component of which is WC, and which contains one or more elements selected from a group consisting of nickel, chromium and cobalt as a binder material thereof, or a sprayed coating, the main component of which is Cr.sub.3 C.sub.2, and which contains NiCr as a binder material, after the sprayed coating has been formed, heating at from 300.degree. C. to 550.degree. C. is performed for one hour or longer so that hardness and wear resistance equivalent to those of a WC - 12% sintered article is attained. ## Claims ### Claim 1 A bearing unit comprising: a bearing; and a sleeve which is in slide-contact with said bearing, wherein said bearing and/or said sleeve made of a metal having a contact surface applied with a sprayed coating, the main component of which is WC, and which contains one or more elements selected from a group consisting of nickel, chromium and cobalt as a binder material thereof, and the number ratio of blow holes contained in the surface of said sprayed coating and having a size of not smaller than 20 .mu.m is 15 per square millimeter or less. ### Claim 2 (depends on 1) A bearing unit according to claim 1, wherein the thickness of said sprayed coating is from 100 .mu.m to 200 .mu.m, and a contact portion of said sleeve and/or said bearing is divided into two or more sections. ### Claim 3 A bearing unit comprising: a bearing; and a sleeve which is in slide-contact with said bearing, wherein either of said bearing and said sleeve made of a metal has a contact surface applied with a sprayed coating, the main component of which is WC, and which contains one or more elements selected from a group consisting of nickel, chromium and cobalt as a binder material thereof, and the residual is made of SiC or Si.sub.3 N.sub.4, or metal having a contact surface area applied with a sprayed coating the main component of which is WC, and which contains one or more elements selected from a group consisting of nickel, chromium and cobalt as a binder material thereof, and metal having a contact surface area applied with a sprayed coating the main component of which is Cr.sub.3 C.sub.2, and which contains nickel and chromium as binder materials or metal which contains SiC or Si.sub.3 N.sub.4 and the number ratio of blow holes contained in the surface of said sprayed coating and having a size of not smaller than 20 .mu.m is 15 per square millimeter or less. ### Claim 4 (depends on 3) A bearing unit according to claim 3, wherein the thickness of said sprayed coating is from 100 .mu.m to 200 .mu.m, and a contact portion of said sleeve and/or said bearing is divided into two or more sections. ### Claim 5 A bearing unit comprising: a bearing; and a sleeve which is in contact with said bearing, wherein said bearing and/or said sleeve made of metal has a contact surface applied with a sprayed coating, the main component of which is WC, and which contains one or more elements selected from a group consisting of nickel, chromium and cobalt as a binder material thereof, and said sprayed coating is heated at a temperature of from 300.degree. C. to 550.degree. C. after said sprayed coating has been formed, said sprayed coating having a hardness of Hv 1000 or higher. ### Claim 6 (depends on 5) A bearing unit according to claim 5, wherein the thickness of said sprayed coating is from 100 .mu.m to 200 .mu.m, and a contact portion of said sleeve and/or said bearing is divided into two or more sections. ### Claim 7 A bearing unit comprising: a bearing; and a sleeve which is in contact with said bearing, wherein said sleeve is made of metal having a contact surface applied with a sprayed coating, the main component of which is WC, and which contains one or more elements selected from a group consisting of nickel, chromium and cobalt as a binder material thereof, and the ratio W/D.sup.2 of weight W (kg) of said sleeve and the outer diameter D (cm) of the same is 0.05 or less. ### Claim 8 (depends on 7) A bearing unit according to claim 7, wherein the thickness of said sprayed coating is from 100 .mu.m to 200 .mu.m, and a contact portion of said sleeve and/or said bearing is divided into two or more sections. ### Claim 9 A bearing member comprising a sprayed coating formed on the surface thereof, wherein the number ratio of blow holes contained in the surface of said sprayed coating and having a size of not less than 20 .mu.m is 15 pieces/mm.sup.2 or less. ### Claim 10 (depends on 9) A bearing member according to claim 9, wherein said sprayed coating is mainly composed of WC and contains one or more elements selected from a group consisting of nickel, chromium and cobalt as a binder material thereof, or mainly composed of Cr.sub.3 C.sub.2 and contains nickel and chromium as a binder material thereof.