Method for identifying leaks by means of an actuator

Patent metadata

Field	Value
Publication number	US-11111972-B2
Application number	US-201816630300-A
Country	US
Kind code	B2
Filing date	Jul 6, 2018
Priority date	Jul 11, 2017
Publication date	Sep 7, 2021
Grant date	Sep 7, 2021

Abstract

A method for controlling an actuator includes providing the actuator with a control unit, a drive unit including an electric motor with a stator and a rotor, a rotor position sensor, connected to the control unit, for detecting a rotation of the rotor, and a displacer unit, drivable by the rotation of the rotor, for displacing a fluid. The displacer unit includes a geometric displacement volume per revolution of the rotor. The method also includes generating a predetermined pressure at the displacer unit by applying an electrical driving power to the electric motor, maintaining the predetermined pressure over a predetermined time interval, determining the rotation of the rotor with the rotor position sensor during the predetermined time interval, and determining a leakage volume flow.

First claim

The invention claimed is:

1. A method for controlling an actuator, comprising:
providing the actuator comprising:
a control unit;
a drive unit comprising an electric motor including a stator and a rotor;
a rotor position sensor, connected to the control unit, for detecting a rotation of the rotor; and
a displacer unit, drivable by the rotation of the rotor, for displacing a fluid, the displacer unit comprising a geometric displacement volume per revolution of the rotor;

generating a predetermined pressure at the displacer unit by applying an electrical driving power to the electric motor;
maintaining the predetermined pressure over a predetermined time interval;
determining the rotation of the rotor with the rotor position sensor during the predetermined time interval; and
determining a leakage volume flow.

2. The method of claim 1 , wherein the leakage volume flow is determined in accordance with the formula: QL=deltaINC * Vg/(INC/rotation)/t, wherein:
QL is the leakage volume flow measured in liters/second;
deltaINC is a number of increments performed by the rotor in the predetermined time interval; and
Vg is the geometric displacement volume per revolution of the rotor measured in liters/revolution;
INC/rotation is a number of increments per revolution of the rotor; and
t is the predetermined time interval in seconds.

3. The method of claim 1 , wherein the method is carried out at different predetermined pressures.

4. The method of claim 1 , wherein the leakage volume flow is considered in volume flow control of the displacer unit by the actuator.

5. The method of claim 1 , wherein a characteristic map for the leakage volume flow for different pressures is determined by determining the leakage volume flow at the predetermined pressure.

6. The method of claim 1 , wherein the method is carried out continuously or periodically.

7. The method of claim 1 , wherein the leakage volume flow is determined in accordance with the formula: QL=deltaINC * Vg/(INC/rotation)/t, wherein:
QL is the leakage volume flow;
deltaINC is a number of increments performed by the rotor in the predetermined time interval;
Vg is the geometric displacement volume per revolution of the rotor;
INC/rotation is a number of increments per revolution of the rotor; and
t is the predetermined time interval.

8. A motor vehicle, comprising:
an actuator comprising:
a control unit;
a drive unit comprising an electric motor including a stator and a rotor;
a rotor position sensor, connected to the control unit, for detecting a rotation of the rotor; and
a displacer unit, drivable by the rotation of the rotor, for displacing a fluid, the displacer unit comprising a geometric displacement volume per revolution of the rotor; and

a motor vehicle component, actuatable by the actuator, wherein the actuator is arranged to:
generate a predetermined pressure at the displacer unit when an electrical driving power is applied to the electric motor;
maintain the predetermined pressure over a predetermined time interval;
determine the rotation of the rotor with the rotor position sensor during the predetermined time interval; and
determine a leakage volume flow.

9. The motor vehicle of claim 8 wherein the motor vehicle component is a clutch or a transmission assembly.

Assignees

• Schaeffler Technologies Ag

Inventors

• Weiler Manuel
• Willeke Roshan

Classifications

• F16D2500/1026

  Hydraulic · CPC title

• F16D2500/7041

  Position · CPC title

• F16D48/066

  Control of fluid pressure, e.g. using an accumulator (F16D48/062, F16D48/068 take precedence) · CPC title

• F16D2500/3166

  Detection of an elapsed period of time · CPC title

• F16H61/32 Primary

  Electric motors  {, actuators or related electrical control means}  therefor · CPC title