# US 10,309,530 B2 · Automatic transmission > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,309,530 B2 - Document ID: US10309530B2 - Status: Granted - Kind: B2 - Application number: 15/517,790 - Filed: 2015-11-09 - Published: 2017-10-26 - Granted: 2019-06-04 - Earliest claimed: 2014-11-28 - Assignees: Aisin Aw Co., Ltd.; Toyota Jidosha Kabushiki Kaisha - Applicants: Aisin Aw Co., Ltd.; Toyota Jidosha Kabushiki Kaisha - Inventors: Yuhei Yoshioka; Yasushi Sato; Toshihiko Kamiya; Akio Murasugi; Masahide Ichikawa - Web page: https://patentgrep.com/patent/US10309530B2 ## CPC - F16H 61/38: Control of exclusively fluid gearing - F16H 39/42: pump and motor being of different types - F16H 61/0021: {Generation or control of line pressure} - F16H 61/0267: {Layout of hydraulic control circuits, e.g. arrangement of valves} - F16H 61/0276: {Elements specially adapted for hydraulic control units, e.g. valves} - F16H 61/64: controlled by changing the amount of liquid in the working circuit - F16H 59/46: dependent on a comparison between speeds - F16H 2059/366: {Engine or motor speed} - F16H 2059/385: {Turbine speed} - F16H 2061/1236: {using fail priority valves} - F16H 2061/124: {Limiting the input power, torque or speed} - F16H 2061/1252: {Fail safe valves} - F16H: GEARING ## Abstract An automatic transmission where the control portion controls the adjustment solenoid valve so that the circulation hydraulic pressure equals to a second circulation hydraulic pressure higher than the first circulation hydraulic pressure when the rotational speed difference between the output rotational speed of the fluid transmission device and the rotational speed of the driving source is more than the predetermined rotational speed. ## Claims ### Claim 1 An automatic transmission comprising: a fluid transmission device fluid-transmitting rotation of a driving source via oil filled therein; a transmission mechanism changing an output rotational speed from the fluid transmission device and outputting a changed rotational speed; a hydraulic pressure control device including a circulation hydraulic pressure adjustment valve adjusting a hydraulic pressure discharged by an oil pump to a circulation hydraulic pressure circulating through the fluid transmission device and an adjustment solenoid valve supplying a signal pressure to the circulation hydraulic pressure adjustment valve; and a control portion that acquires a rotational speed of the driving source and that acquires an output rotational speed of the fluid transmission device, wherein: the control portion controls the adjustment solenoid valve so that the circulation hydraulic pressure equals to a first circulation hydraulic pressure when a rotational speed difference between the output rotational speed of the fluid transmission device and the rotational speed of the driving source is equal to or less than a predetermined rotational speed and the control portion controls the adjustment solenoid valve so that the circulation hydraulic pressure equals to a second circulation hydraulic pressure higher than the first circulation hydraulic pressure when the rotational speed difference between the output rotational speed of the fluid transmission device and the rotational speed of the driving source is more than the predetermined rotational speed. ### Claim 2 (depends on 1) The automatic transmission according to claim 1, wherein the control portion makes the second circulation hydraulic pressure closer to the first circulation hydraulic pressure as the output rotational speed of the fluid transmission device becomes closer to the rotational speed of the driving source. ### Claim 3 (depends on 2) The automatic transmission according to claim 2, wherein the control portion increases the circulation hydraulic pressure by instructing an instruction value to the adjustment solenoid valve based on the rotational speed of the driving source and the output rotational speed of the fluid transmission device in accordance with an instruction value map recording correspondence among the rotational speed of the driving source, the output rotational speed of the fluid transmission device, and the instruction value for instructing the adjustment solenoid valve. ### Claim 4 (depends on 3) The automatic transmission according to claim 3, wherein: the hydraulic pressure control device has a line pressure adjustment valve adjusting a hydraulic pressure discharged by the oil pump to a line pressure in accordance with the signal pressure of the adjustment solenoid valve, the circulation hydraulic pressure adjustment valve adjusts a discharge pressure of the line pressure to the circulation hydraulic pressure, the control portion makes the circulation hydraulic pressure equal to the first circulation hydraulic pressure by controlling the adjustment solenoid valve in accordance with an input torque calculated from a speed ratio between the rotational speed of the driving source and the output rotational speed of the fluid transmission device and makes the circulation hydraulic pressure equal to the second circulation hydraulic pressure by controlling the adjustment solenoid valve so as to increase the line pressure. ### Claim 5 (depends on 4) The automatic transmission according to claim 4, wherein the first circulation hydraulic pressure is a hydraulic pressure enabling power transmission of the fluid transmission device. ### Claim 6 (depends on 5) The automatic transmission according to claim 5, wherein: the fluid transmission device has a lock-up clutch engaged when a lock-up engagement pressure is supplied, the hydraulic pressure control device has a switching valve for turning on or off supply of the lock-up engagement pressure, and the control portion increases the circulation hydraulic pressure by controlling the adjustment solenoid valve when the supply of the lock-up engagement pressure is turned off by the switching valve. ### Claim 7 (depends on 6) The automatic transmission according to claim 6, wherein the control portion starts control for making the circulation hydraulic pressure equal to the second circulation hydraulic pressure immediately after the driving source is started. ### Claim 8 An automatic transmission comprising: a fluid transmission device fluid-transmitting rotation of a driving source via oil filled therein; a transmission mechanism changing an output rotational speed from the fluid transmission device and outputting a changed rotational speed; a hydraulic pressure control device including a circulation hydraulic pressure adjustment valve adjusting a hydraulic pressure discharged by an oil pump to a circulation hydraulic pressure circulating through the fluid transmission device and an adjustment solenoid valve supplying a signal pressure to the circulation hydraulic pressure adjustment valve; and a control portion controlling the adjustment solenoid valve so that the circulation hydraulic pressure equals to a first circulation hydraulic pressure when the fluid transmission device is filled with oil and controlling the adjustment solenoid valve so that the circulation hydraulic pressure equals to a second circulation hydraulic pressure higher than the first circulation hydraulic pressure when the oil has leaked from the fluid transmission device. ### Claim 9 (depends on 8) The automatic transmission according to claim 8, wherein the control portion acquires a rotational speed of the driving source, acquires an output rotational speed of the fluid transmission device, and determines whether the oil has leaked from the fluid transmission device based on a difference between the rotational speed of the driving source and the output rotational speed of the fluid transmission device. ### Claim 10 (depends on 9) The automatic transmission according to claim 9, wherein the control portion increases the second circulation hydraulic pressure more greatly than the first circulation hydraulic pressure as the rotational speed of the driving source becomes larger than the output rotational speed of the fluid transmission device. ### Claim 11 (depends on 10) The automatic transmission according to claim 10, wherein the control portion makes the second circulation hydraulic pressure closer to the first circulation hydraulic pressure as the output rotational speed of the fluid transmission device becomes closer to the rotational speed of the driving source. ### Claim 12 (depends on 11) The automatic transmission according to claim 11, wherein the control portion determines that oil in the fluid transmission device has leaked when a difference between the rotational speed of the driving source and the output rotational speed of the fluid transmission device is larger than a predetermined rotational speed. ### Claim 13 (depends on 12) The automatic transmission according to claim 12, wherein the control portion increases the circulation hydraulic pressure by instructing an instruction value to the adjustment solenoid valve based on the rotational speed of the driving source and the output rotational speed of the fluid transmission device in accordance with an instruction value map recording correspondence among the rotational speed of the driving source, the output rotational speed of the fluid transmission device, and the instruction value for instructing the adjustment solenoid valve. ### Claim 14 (depends on 13) The automatic transmission according to claim 13, wherein: the hydraulic pressure control device has a line pressure adjustment valve adjusting a hydraulic pressure discharged by the oil pump to a line pressure in accordance with the signal pressure of the adjustment solenoid valve, the circulation hydraulic pressure adjustment valve adjusts a discharge pressure of the line pressure to the circulation hydraulic pressure, the control portion makes the circulation hydraulic pressure equal to the first circulation hydraulic pressure by controlling the adjustment solenoid valve in accordance with an input torque calculated from a speed ratio between the rotational speed of the driving source and the output rotational speed of the fluid transmission device and makes the circulation hydraulic pressure equal to the second circulation hydraulic pressure by controlling the adjustment solenoid valve so as to increase the line pressure. ### Claim 15 (depends on 14) The automatic transmission according to claim 14, wherein the first circulation hydraulic pressure is a hydraulic pressure enabling power transmission of the fluid transmission device. ### Claim 16 (depends on 15) The automatic transmission according to claim 15, wherein: the fluid transmission device has a lock-up clutch engaged when a lock-up engagement pressure is supplied, the hydraulic pressure control device has a switching valve for turning on or off supply of the lock-up engagement pressure, and the control portion increases the circulation hydraulic pressure by controlling the adjustment solenoid valve when the supply of the lock-up engagement pressure is turned off by the switching valve. ### Claim 17 (depends on 16) The automatic transmission according to claim 16, wherein the control portion starts control for making the circulation hydraulic pressure equal to the second circulation hydraulic pressure immediately after the driving source is started.