# US 9,751,372 B2 · System for determining an axle load for an agricultural tractor > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,751,372 B2 - Document ID: US9751372B2 - Status: Granted - Kind: B2 - Application number: 15/066,041 - Filed: 2016-03-10 - Published: 2016-10-13 - Granted: 2017-09-05 - Earliest claimed: 2015-04-09 - Assignees: Deere & Company - Applicants: Deere & Company - Inventors: Sebastian Traut; Guenther Wolf; Michael Meid - Web page: https://patentgrep.com/patent/US9751372B2 ## CPC - B60G 17/016: characterised by their responsiveness, when the vehicle is travelling, to specific motion, a specific condition, or driver input {(B60G17/017 takes precedence)} - B60G 17/018: characterised by the use of a specific signal treatment or control method - B60G 17/019: characterised by the type of sensor or the arrangement thereof {(B60G17/01941 takes precedence)} - B60G 17/01941: {characterised by the use of piezoelectric elements, e.g. sensors or actuators} - B60G 17/0195: characterised by the regulation being combined with other vehicle control systems {(conjoint control of vehicle sub-units including control of suspension systems B60W10/22)} - B60Q 9/00: Arrangement or adaptation of signal devices not provided for in one of main groups B60Q1/00 - B60Q7/00 {, e.g. haptic signalling} - G01G 19/10: having fluid weight-sensitive devices - B60G 2300/08: Agricultural vehicles - B60G 2300/082: Tractors - B60G 2400/51: in suspension unit - B60G 2400/5182: Fluid damper - B60G 2400/60: Load - B60G 2600/042: Monitoring means - B60G 2600/044: Alarm means - B60G 2800/70: Estimating or calculating vehicle parameters or state variables - B60G: VEHICLE SUSPENSION ARRANGEMENTS (air-cushion vehicles B60V; {cycle suspensions B62K25/00}) - B60Q: ARRANGEMENT OF SIGNALLING OR LIGHTING DEVICES, THE MOUNTING OR SUPPORTING THEREOF OR CIRCUITS THEREFOR, FOR VEHICLES IN GENERAL - G01G: WEIGHING (sorting by weighing B07C5/16) ## Abstract A system for determining an axle load for an agricultural tractor. The system includes an axle or wheel suspension device arranged on a front axle of the agricultural tractor and has a hydraulic spring strut having a hydraulic cylinder and a hydraulic piston dividing the hydraulic cylinder into an annular space and a piston space. A first pressure sensor detects a first working pressure, which is present in the annular space. A second pressure sensor detects a second working pressure, which is present in the piston space. A control device calculates a front axle load variable which represents an axle load acting on a front axle on the basis of a pressure force difference derived from the first and second working pressures. ## Claims ### Claim 1 A system for determining the axle load for an agricultural tractor, comprising: a wheel suspension device, arranged on a front axle of the agricultural tractor, the device including a hydraulic spring strut having a hydraulic cylinder and a hydraulic piston dividing the hydraulic cylinder into an annular space and a piston space; a first pressure sensor configured to detect a first working pressure, which is present in the annular space; a second pressure sensor configured to detect a second working pressure, which is present in the piston space; and a control device configured to calculate, on the basis of a pressure force difference derived from the first and second working pressures, a front axle load variable, which represents an axle load acting on the front axle. ### Claim 2 (depends on 1) The system of claim 1, wherein the front axle is pivotably suspended by a trailing arm and the control device takes a lever length specific to a trailing link into consideration in the calculation of the front axle load variable. ### Claim 3 (depends on 2) The system of claim 2, wherein the control device is configured to compare the calculated front axle load variable to a permissible operating value range, wherein the control device causes driver information to be output in the event of a deviation from the permissible operating value range. ### Claim 4 (depends on 3) The system of claim 3, wherein the control device, in order to output the driver information, triggers a user interface, is configured to Output one of an acoustic warning signal, a visual warning signal, and a corresponding information text indicating overloading or underloading of the front axle. ### Claim 5 (depends on 4) The system of claim 4, wherein the control device is configured to calculate a rear axle load variable, representing an axle load acting on a rear axle, by proceeding from a force effect appearing at a rear-end lifting mechanism due to a towed load. ### Claim 6 (depends on 5) The system of claim 5, wherein the control device is configured to determine a center of gravity position oriented in the longitudinal direction of the agricultural tractor on the basis of the calculated front axle load variable in conjunction with the calculated rear axle load variable. ### Claim 7 (depends on 6) The system of claim 6, wherein the control device is configured to determine the current total mass of the agricultural tractor on the basis of the calculated front axle load variable in conjunction with the calculated rear axle load variable. ### Claim 8 (depends on 7) The system of claim 7, wherein the control device is configured to trigger a user interface to display driver information indicating the current total mass of the agricultural tractor on the basis of the determined total axle load variable. ### Claim 9 An agricultural tractor comprising: a wheel suspension device, arranged on a front axle of the agricultural tractor, the device including a hydraulic spring strut having a hydraulic cylinder and a hydraulic piston dividing the hydraulic cylinder into an annular space and a piston space; a first pressure sensor configured to detect a first working pressure, which is present in the annular space; a second pressure sensor configured to detect a second working pressure, which is present in the piston space; and a control device configured to calculate, on the basis of a pressure force difference derived from the first and second working pressures, a front axle load variable, which represents an axle load acting on the front axle. ### Claim 10 (depends on 9) The agricultural tractor of claim 9, further comprising: a chassis formed from a portion of the agricultural tractor; and a trailing arm having one end coupled to the chassis and a free end; wherein the front axle is pivotally suspended from the chassis via the wheel suspension device positioned at the free end of the trailing arm. ### Claim 11 (depends on 9) The agricultural tractor of claim 9, wherein the control device modifies the suspension device to regulate the level of the agricultural tractor relative to a ground surface. ### Claim 12 (depends on 9) The agricultural tractor of claim 9, wherein the wheel suspension device includes at least one accumulator. ### Claim 13 (depends on 9) The agricultural tractor of claim 9, wherein the control device alters a spring stiffness of the Wheel suspension device based on the front axle load variable. ### Claim 14 (depends on 9) The agricultural tractor of claim 9, further comprising: at least one front tire coupled to the wheel suspension device; and a central tire inflation system configured to alter the pressure of the at least one front tire; wherein, the control device alters the pressure of the at least one front tire via the central tire inflation system based on the front axle load variable.