# US 2018/0320731 A1 · Length-Adjustable Connecting Rod > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2018/0320731 A1 - Document ID: US20180320731A1 - Status: Published application - Kind: A1 - Application number: 15/771,283 - Filed: 2016-11-07 - Published: 2018-11-08 - Earliest claimed: 2015-11-05 - Assignees: AVL List GmbH - Applicants: Avl List GmbH - Inventors: Helmut Melde-Tuczai; Siegfried Hartwig - Web page: https://patentgrep.com/patent/US20180320731A1 ## CPC - F16C 7/06: Adjustable connecting-rods - F02B 75/045: {by means of a variable connecting rod length} - F15B 15/14: of the straight-cylinder type - F16C: SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS - F02B: INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL (gas-turbine plants F02C; hot-gas or combustion-product positive-displacement engine plants F02G) - F15B: SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR ## Abstract The invention relates to a length-adjustable connecting rod (1) for a reciprocating piston machine, comprising at least one first rod part (2) with a small connecting rod eye (3) and at least one second rod part (4) with a large connecting rod eye (5), both rod parts (2, 4) being movable in relation to each other or inside each other in a telescoping manner. The second rod part (4) comprises a guide cylinder (8) and the first rod part (2) is securely connected to a piston element (7) that can move longitudinally in the guide cylinder (8), a first high-pressure chamber (10) being mounted on a first side of the piston element (7) between the second rod part (4) and the piston element (7), and a second high-pressure chamber (12) being mounted on a second side of the piston element (7), at least one sealing element (22, 24) being provided for sealing at least one high-pressure chamber (10, 12). The aim of the invention is to allow a wear-resistant seal between the two rod parts (2, 4) as easily, compactly and reliably as possible. To this end, the piston element (7) is non-positively connected to the first rod part (2) by means of an interference fit (30) in a interference-fit region (30a). ## Claims ### Claim 1 A length-adjustable connecting rod (1) for a reciprocating engine, in particular an internal combustion engine, comprising at least one first rod part (2) with a small connecting rod eye (3) and at least one second rod part (4) with a large connecting rod eye (5), which two rod parts (2, 4) are movable in relation to each other and/or inside each other in a telescoping manner in the direction of a longitudinal axis (1a) of the connecting rod (1), wherein the second rod part (4) comprises a guide cylinder (8) and the first rod part (2) is fixedly connected to a piston element (7) that can move longitudinally in the guide cylinder (8), wherein a first high-pressure chamber (10) is defined on a first side of the piston element (7) between the second rod part (4) and the piston element (7), and a second high-pressure chamber (12) is defined on a second side of the piston element (7), wherein each high-pressure chamber (10, 12) is flow-connected to at least one oil passage (15, 16), wherein at least one sealing element (22, 24) is provided for sealing at least one high-pressure chamber (10, 12), and wherein the piston element (7) is non-positively connected to the first rod part (2) via an interference fit (30) in a press-fit region (30a). ### Claim 2 (depends on 1) The connecting rod (1) according to claim 1, wherein the press-fit region (30a) of the piston element (7) is formed by an inner jacket surface (27b) of the annular end region (7a) of the piston element (7) facing the small connecting rod eye (3) and the press-fit region (30b) of the first rod part (2) is formed by an outer jacket surface (23a) of a shoulder region (23) of the first rod part (2) facing away from the small connecting rod eye (3). ### Claim 3 (depends on 1) The connecting rod (1) according to claim 1, wherein for sealing the second high-pressure chamber (12) between the first rod part (2) and the second rod part (4) or a clamping sleeve (33) fixedly connected to the second rod part (4), at least one second sealing element (24) is arranged in a force-free manner adjacent to the press-fit region (30a) of the piston element (7) in the direction of the longitudinal axis (1a) between the first rod part (2) and the piston element (7), wherein preferably the second sealing element (24) has a defined play in the direction of the longitudinal axis (1a) relative to the piston element (7) and/or the second rod part (2). ### Claim 4 (depends on 1) The connecting rod (1) according to claim 1, wherein the piston element (7) has a first piston part (17) and a second piston part (27), wherein the first piston part (17) adjoins the first high-pressure chamber (10) and the second piston part (27) adjoins the second high-pressure chamber (12). ### Claim 5 (depends on 4) The connecting rod (1) according to claim 4, wherein the second piston part (27) forms the press-fit region (30a) of the piston element (7). ### Claim 6 (depends on 4) The connecting rod (1) according to claim 4, wherein the first piston part (17) is screwed together with the first rod part (2). ### Claim 7 (depends on 4) The connecting rod (1) according to claim 4, wherein the first piston part (17) has a blind bore (18) with an internal thread (19) which is screwed to an external thread (20) of the first rod part (2). ### Claim 8 (depends on 4) The connecting rod (1) according to claim 4, wherein the first piston part (17) and the second piston part (27) are interconnected by annular contact surfaces (17a, 27a) in the direction of the longitudinal axis (1a), which are preferably arranged normally on the longitudinal axis (1 a). ### Claim 9 (depends on 8) The connecting rod (1) according to claim 8, wherein for sealing the first high-pressure chamber (10) between the piston element (7) and guide cylinder (8) at least one first sealing element (22) is arranged adjacent to at least one contact surface (17a, 27a) in the direction of the longitudinal axis (1a) without force between the first piston part (17) and the second piston part (27). ### Claim 10 (depends on 4) The connecting rod (1) according to claim 4, wherein a first sealing element (22) which is arranged for sealing the first high-pressure chamber (10) between the piston element (7) and the guide cylinder (8) has a defined play in the direction of the longitudinal axis (1a) relative to the first piston part (17) and/or the second piston part (27).