# US 9,435,422 B2 · Hydraulic system of a transmission device with a lubrication circuit > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,435,422 B2 - Document ID: US9435422B2 - Status: Granted - Kind: B2 - Application number: 14/522,802 - Filed: 2014-10-24 - Published: 2015-04-30 - Granted: 2016-09-06 - Earliest claimed: 2014-10-24 - Assignees: ZF Friedrichshafen AG - Applicants: ZF Friedrichshafen AG - Inventors: Markus Herrmann; Robert Erath - Web page: https://patentgrep.com/patent/US9435422B2 ## CPC - F16H 57/0413: {Controlled cooling or heating of lubricant; Temperature control therefor} - F16H 57/0446: {the supply forming part of the transmission control unit, e.g. for automatic transmissions} - F16H 57/0476: {Electric machines and gearing, i.e. joint lubrication or cooling or heating thereof} - F16H 61/0021: {Generation or control of line pressure} - F16H 2061/0037: {characterised by controlled fluid supply to lubrication circuits of the gearing} - Y10T 137/87362: Including cleaning, treating, or heat transfer feature - F16H: GEARING - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract A hydraulic system of a transmission device with a lubrication circuit, which is supplied with hydraulic fluid downstream of a cooling device for cooling and lubrication, is described. One part of the volume flow of hydraulic fluid led through the cooling device is able to be discharged downstream of the cooling device and upstream of the lubrication circuit in the direction of a hydraulic fluid reservoir. A valve device arranged downstream of the cooling device and upstream of the lubrication circuit is provided, which valve device is transferable into a first operating state and into a second operating state depending on the operating condition, whereas, in the first operating state of the valve device, a volume flow of hydraulic fluid supplied to the valve device is able to be discharged at least partially in the direction of the hydraulic fluid reservoir, while, in the second operating state of the valve device, a volume flow of hydraulic fluid supplied to the valve device is able to be supplied at least partially to a shifting element of the transmission device. ## Claims ### Claim 1 A hydraulic system in a transmission device, comprising: a lubrication circuit that is supplied with hydraulic fluid downstream of a cooling device, wherein at least part of the volume of flow of hydraulic fluid through the cooling device is discharged upstream of the lubrication circuit; a valve device arranged downstream of the cooling device and upstream of the lubrication circuit to receive the volume flow of hydraulic fluid discharged upstream of the lubrication circuit, the valve device transferable between a first operating state and a second operating state; in the first operating state of the valve device, a volume flow of hydraulic fluid supplied to the valve device from the cooling device is discharged to a hydraulic fluid reservoir; and in the second operating state of the valve device, a volume flow of hydraulic fluid supplied to the valve device from the cooling device is supplied at least partially to a shifting element in the transmission device. ### Claim 2 (depends on 1) The hydraulic system as in claim 1, wherein the valve device is a shifting valve device having a first shifting state wherein the volume flow of hydraulic fluid to the shifting device is discharged to the hydraulic fluid reservoir, and a second shifting state wherein the volume flow of hydraulic fluid supplied to the valve device is supplied at least partially to a shifting element in the transmission device. ### Claim 3 (depends on 2) The hydraulic system as in claim 2, further comprising valve device upstream of the shifting valve device that adjusts the volume flow of hydraulic fluid to the shifting valve device. ### Claim 4 (depends on 3) The hydraulic system as in claim 3, wherein operating pressure of the shifting valve device is adjustable by way of a regulating valve device that supplies the shifting valve device with the operating pressure. ### Claim 5 (depends on 1) The hydraulic system as in claim 1, further comprising a stator of an electric engine arranged downstream of the cooling device and upstream of the lubrication circuit that is cooled by hydraulic fluid from the cooling device. ### Claim 6 (depends on 5) The hydraulic system as in claim 5, further comprising a rotor of an electric engine arranged downstream of the cooling device and upstream of the lubrication circuit that is cooled by hydraulic fluid from the cooling device. ### Claim 7 (depends on 1) The hydraulic system as in claim 1, wherein the shifting element comprises a piston, and a chamber that is supplied with the hydraulic fluid that counteracts an actuation force on the piston. ### Claim 8 (depends on 1) The hydraulic system as in claim 1, further comprising a lubricant pressure regulator device arranged upstream of the cooling device to adjust flow of the hydraulic fluid through the cooling device. ### Claim 9 (depends on 1) The hydraulic system as in claim 1, further comprising a line upstream of the cooling device through which a volume flow of hydraulic fluid is directed to a filling circuit. ### Claim 10 (depends on 1) The hydraulic system as in claim 1, further comprising a line downstream of the cooling device circuit and upstream of the lubrication circuit through which a volume flow of hydraulic fluid is directed to an additional shifting element. ### Claim 11 A hydraulic system in a transmission device, comprising: a lubrication circuit that is supplied with hydraulic fluid downstream of a cooling device, wherein at least part of the volume of flow of hydraulic fluid through the cooling device is discharged upstream of the lubrication circuit to a hydraulic fluid reservoir; a valve device arranged downstream of the cooling device and upstream of the lubrication circuit, the valve device transferable between a first operating state and a second operating state; in the first operating state of the valve device, a volume flow of hydraulic fluid supplied to the valve device is discharged to a hydraulic fluid reservoir; in the second operating state of the valve device, a volume flow of hydraulic fluid supplied to the valve device is supplied at least partially to a shifting element in the transmission device; wherein the valve device is a shifting valve device having a first shifting state wherein the volume flow of hydraulic fluid to the shifting device is discharged to the hydraulic fluid reservoir, and a second shifting state wherein the volume flow of hydraulic fluid supplied to the valve device is supplied at least partially to a shifting element in the transmission device; further comprising valve device upstream of the shifting valve device that adjusts the volume flow of hydraulic fluid to the shifting valve device; wherein operating pressure of the shifting valve device is adjustable by way of a regulating valve device that supplies the shifting valve device with the operating pressure; and wherein the regulating valve device is pilot controlled and operating pressure of the shifting valve device is adjustable by adjusting a pilot pressure at the regulating valve device. ### Claim 12 A hydraulic system in a transmission device, comprising: a lubrication circuit that is supplied with hydraulic fluid downstream of a cooling device, wherein at least part of the volume of flow of hydraulic fluid through the cooling device is discharged upstream of the lubrication circuit to a hydraulic fluid reservoir; a valve device arranged downstream of the cooling device and upstream of the lubrication circuit, the valve device transferable between a first operating state and a second operating state; in the first operating state of the valve device, a volume flow of hydraulic fluid supplied to the valve device is discharged to a hydraulic fluid reservoir; in the second operating state of the valve device, a volume flow of hydraulic fluid supplied to the valve device is supplied at least partially to a shifting element in the transmission device; wherein the valve device is a shifting valve device having a first shifting state wherein the volume flow of hydraulic fluid to the shifting device is discharged to the hydraulic fluid reservoir, and a second shifting state wherein the volume flow of hydraulic fluid supplied to the valve device is supplied at least partially to a shifting element in the transmission device; further comprising valve device upstream of the shifting valve device that adjusts the volume flow of hydraulic fluid to the shifting valve device; wherein operating pressure of the shifting valve device is adjustable by way of a regulating valve device that supplies the shifting valve device with the operating pressure; and further comprising a throttle device arranged in a line connecting the regulating valve device to the shifting valve device downstream of a branch point, wherein at the branch point volume flow of hydraulic fluid through the regulating valve device is directed in part to the shifting element and in part to the shifting valve device. ### Claim 13 (depends on 12) The hydraulic system as in claim 12, further comprising a throttle device arranged in the line between the regulating valve device and the shifting element upstream of the branch point. ### Claim 14 A hydraulic system in a transmission device, comprising: a lubrication circuit that is supplied with hydraulic fluid downstream of a cooling device, wherein at least part of the volume of flow of hydraulic fluid through the cooling device is discharged upstream of the lubrication circuit to a hydraulic fluid reservoir; a valve device arranged downstream of the cooling device and upstream of the lubrication circuit, the valve device transferable between a first operating state and a second operating state; in the first operating state of the valve device, a volume flow of hydraulic fluid supplied to the valve device is discharged to a hydraulic fluid reservoir; in the second operating state of the valve device, a volume flow of hydraulic fluid supplied to the valve device is supplied at least partially to a shifting element in the transmission device; wherein the valve device is a shifting valve device having a first shifting state wherein the volume flow of hydraulic fluid to the shifting device is discharged to the hydraulic fluid reservoir, and a second shifting state wherein the volume flow of hydraulic fluid supplied to the valve device is supplied at least partially to a shifting element in the transmission device; further comprising valve device upstream of the shifting valve device that adjusts the volume flow of hydraulic fluid to the shifting valve device; wherein operating pressure of the shifting valve device is adjustable by way of a regulating valve device that supplies the shifting valve device with the operating pressure; and further comprising a throttle device arranged in a line between the regulating valve device and a pressure regulator device.