# US 8,770,955 B2 · Adjustable rotary pump with reduced wear > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,770,955 B2 - Document ID: US8770955B2 - Status: Granted - Kind: B2 - Application number: 13/464,206 - Filed: 2012-05-04 - Published: 2012-08-30 - Granted: 2014-07-08 - Earliest claimed: 2006-04-19 - Assignees: Schwäbische Hüttenwerke Automotive GmbH - Applicants: Christof Lamparski - Inventors: Christof Lamparski - Web page: https://patentgrep.com/patent/US8770955B2 ## CPC - F04C 14/185: {by varying the useful pumping length of the cooperating members in the axial direction} - F04C 2/18: with similar tooth forms (F04C2/16 takes precedence) - F04C 2230/91: Coating - F05C 2201/903: Aluminium alloy, e.g. AlCuMgPb F34,37 - F05C 2203/0869: Aluminium oxide - F05C 2225/00: Synthetic polymers, e.g. plastics; Rubber - F05C 2225/04: PTFE [PolyTetraFluorEthylene] - F05C 2225/06: Polyamides, e.g. NYLON - F05C 2225/12: Polyetheretherketones, e.g. PEEK - F05C 2251/10: Hardness - F05C 2251/14: Self lubricating materials; Solid lubricants - Y10T 29/49242: Screw or gear type, e.g., Moineau type - F04C: ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS (engines F03C); ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS - F05C: INDEXING SCHEME RELATING TO MATERIALS, MATERIAL PROPERTIES OR MATERIAL CHARACTERISTICS FOR MACHINES, ENGINES OR PUMPS OTHER THAN NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract A rotary pump having a variable delivery volume, including: a casing; a delivery chamber formed in the casing; at least one delivery rotor which is rotatable in the delivery chamber; an actuating member which is arranged facing a front face of the delivery rotor or surrounds the delivery rotor, and is moveable in the casing for adjusting the delivery volume; the actuating member chargeable with an actuating force which is dependent on a fluid requirement; a track which is formed in the casing and guides the actuating member on an actuating member sliding surface in a sliding contact; and a sliding material which forms at least one of the track and the actuating member sliding surface. ## Claims ### Claim 1 A rotary pump having a variable delivery volume, comprising: a casing; a delivery chamber formed in the casing and comprising an inlet for a fluid on a low-pressure side and an outlet for the fluid on a high-pressure side of the pump; at least one delivery rotor which can be rotated in the delivery chamber about a rotational axis; a first actuating member which is arranged facing a front face of the delivery rotor, and can be moved back and forth in the casing for adjusting the delivery volume; the first actuating member being chargeable, in the direction of its mobility, with an actuating force which is dependent on a fluid requirement; a first track which is formed in the casing and guides the first actuating member on a first actuating member sliding surface in a sliding contact; a sliding material which forms at least one of the first actuating member sliding surface and the first track; the first actuating member, a second actuating member and the delivery rotor are part of an adjusting unit which can be moved as a whole back and forth in the casing; the first and second actuating members are each arranged facing one of the front faces of the delivery rotor, and a second track is formed in the casing which guides the second actuating member on its second actuating member sliding surface in a sliding contact; at least one of the second actuating member sliding surface of the second actuating member and the second track consists of the sliding material; wherein the sliding material is a thermoplastic modified with a lubricant; wherein the sliding material is a polymer compound of at least one heat-resistant polymer filled with carbon fibers and a sliding additive comprising at least one of graphite and fluoropolymer. ### Claim 2 (depends on 1) The rotary pump according to claim 1, wherein the sliding material forms the first actuating member sliding surface and the second actuating member sliding surface. ### Claim 3 (depends on 1) The rotary pump according to claim 1, wherein the sliding material exhibits an adhesion energy relative to an opposed material which is at most half an adhesion energy of aluminum relative to the same material. ### Claim 4 (depends on 1) The rotary pump according to claim 1, wherein the sliding material comprises PTFE. ### Claim 5 (depends on 4) The rotary pump according to claim 4, wherein the proportion of polymer is at least 60% by weight and at most 80% by weight. ### Claim 6 (depends on 4) The rotary pump according to claim 4, wherein the proportion of the sliding additive is at least 10% by weight and at most 30% by weight. ### Claim 7 (depends on 4) The rotary pump according to claim 4, wherein the proportion of the carbon fibers is at least 5% by weight and at most 15% by weight. ### Claim 8 (depends on 1) The rotary pump according to claim 1, wherein the at least one heat-resistant polymer is a polymer including copolymer, a mixture of polymers or a polymer blend from the group consisting of polyether sulphone (PES), polysulphone (PSU) and polyphthalamide (PPA). ### Claim 9 (depends on 1) The rotary pump according to claim 1, wherein the at least one heat-resistant polymer is a polymer including copolymer, a mixture of polymers or a polymer blend from the group consisting of polyphenylene sulfide (PPS), polyether ketones (PAEK, PEK, PEEK) and polyamide (PA). ### Claim 10 (depends on 1) The rotary pump according to claim 1, wherein the track is formed by a metal-ceramic layer. ### Claim 11 (depends on 1) The rotary pump according to claim 1, wherein nitrided steel or TiCN forms the first and second tracks. ### Claim 12 (depends on 1) The rotary pump according to claim 1, wherein a casing portion comprising at least one of the first and second tracks at least substantially consists of metal or is formed from a metal as a substrate material and a sliding layer of a second sliding material forming at least one of the first and second tracks is applied to the substrate material or is formed by modifying the substrate material. ### Claim 13 (depends on 12) The rotary pump according to claim 12, wherein a casting material forms the casing portion or the substrate material of the casing portion. ### Claim 14 (depends on 13) The rotary pump according to claim 13, wherein the casting material is a die casting material, a chill casting material or a sand casting material. ### Claim 15 (depends on 12) The rotary pump according to claim 12, wherein the metal is aluminum or an aluminum-based alloy or another light metal. ### Claim 16 (depends on 15) The rotary pump according to claim 15, wherein the metal is aluminum or an aluminum-based alloy which contains silicon, or the metal is an aluminum-based alloy containing at least one of copper and iron. ### Claim 17 (depends on 12) The rotary pump according to claim 12, wherein a ceramic material of the substrate material forms the sliding layer of the second sliding material. ### Claim 18 (depends on 17) The rotary pump according to claim 17, wherein the ceramic material of the substrate material is aluminum oxide (Al203). ### Claim 19 (depends on 1) The rotary pump according to claim 1, wherein at least one of the first and second actuating members including its respective actuating member sliding surface is formed from a metal as a substrate material and a sliding layer of the sliding material forming the respective actuating members sliding surface is applied to the substrate material. ### Claim 20 (depends on 19) The rotary pump according to claim 19, wherein a casing portion comprising the at least one of the first and second tracks at least substantially consists of metal or is formed from a metal as a substrate material and a sliding layer of a second sliding material forming the at least one of the first and second tracks is applied to the substrate material or is formed by modifying the substrate material, and wherein the metal of the casing portion and the metal of the at least one of the first and second actuating members contain the same metallic element at least as their respective main constituent. ### Claim 21 (depends on 1) The rotary pump according to claim 1, wherein the casing, or at least a casing portion which forms at least one of the first and second tracks, is formed from the sliding material. ### Claim 22 (depends on 1) The rotary pump according to claim 1, wherein the actuating force is arranged to counteract an elasticity member, or at least one of the first and second actuating members is an actuating piston configured to be charged with the fluid of the high-pressure side. ### Claim 23 (depends on 1) The rotary pump according to claim 1, wherein the delivery rotor and at least one of the first and second actuating members can be axially moved in relation to the rotational axis. ### Claim 24 (depends on 1) The rotary pump according to claim 1, comprising another delivery rotor which can be rotated in the delivery chamber about another rotational axis, wherein the delivery rotors are in delivery engagement with each other. ### Claim 25 (depends on 1) The rotary pump according to claim 1, wherein the pump is an external-axle rotary pump or an external toothed wheel pump. ### Claim 26 (depends on 1) The rotary pump according to claim 1, wherein the casing is formed from an aluminum-based alloy by sand casting, chill casting or die casting, and the first and second tracks are formed by mechanically machining the casting material. ### Claim 27 A method for manufacturing a rotary pump having a variable delivery volume and including a casing, a delivery chamber formed in the casing and comprising an inlet for a fluid on a low-pressure side and an outlet for the fluid on a high-pressure side of the pump, at least one delivery rotor rotatable in the delivery chamber about a rotational axis, an actuating member which is arranged facing a front face of the delivery rotor or surrounds the delivery rotor, and is moveable in the casing for adjusting the delivery volume and chargeable, in the direction of its mobility, with an actuating force which is dependent on a fluid requirement, and a track which is formed in the casing and guides the actuating member on an actuating member sliding surface in a sliding contact; the method comprising: a) forming a casing portion forming the track from a metal; b) forming at least a portion of the actuating member from a metal; and c) injection molding a plastic sliding layer around at least one of the casing portion forming the track or the portion of the actuating member formed from a metal wherein the sliding surface is formed by a surface of a plastic sliding layer. ### Claim 28 (depends on 27) The method according to claim 27, wherein at least one of the casing portion forming the track and the at least a portion of the actuating member is formed from a light metal. ### Claim 29 (depends on 27) The method according to claim 27, wherein the casing portion is formed from an aluminum-based alloy by sand casting, chill casting or die casting, and the track is preferably formed by mechanically machining the casting material. ### Claim 30 (depends on 27) The method according to claim 27, wherein the plastic sliding layer contains a sliding additive.