Hydrostatic actuator and arrangement of a hydrostatic actuator in a motor vehicle

Patent metadata

Field	Value
Publication number	US-9784256-B2
Application number	US-201213650032-A
Country	US
Kind code	B2
Filing date	Oct 11, 2012
Priority date	Apr 12, 2010
Publication date	Oct 10, 2017
Grant date	Oct 10, 2017

Abstract

A hydrostatic actuator and an arrangement for attaching it to a receiving component are provided. The hydrostatic actuator has a master cylinder containing a housing and a piston movable axially within the housing which acts on a pressure chamber filled with a pressurizing agent. The piston is driven by a rotary-driven electric motor having a stator and a rotor, by a rolling planetary transmission that converts the rotary drive to an axial motion. In order to be able to produce such a hydrostatic actuator with little need for construction space, cost-effectively and with better quality, a supporting of the rolling planetary transmission is simplified, and the cooling and shielding of an electronic controller and the pressure behavior of the hydrostatic actuator is improved.

First claim

What is claimed is:

1. A hydrostatic actuator for a motor vehicle comprising:
a housing;
an electric motor located within the housing, the electric motor including a rotor situated within a stator;
a piston axially movable in the housing, the piston acting on a pressure chamber filled with a pressurizing agent;
a rolling planetary transmission within the housing and including rolling planetary bodies and ring gear sections that interact with a spindle having a first axial end and a second axial end, the rolling planetary transmission converting a rotary propulsion of the electric motor to an axial motion of the piston such that the piston moves axially with respect to the spindle; and
a single radial bearing supporting the spindle near the first axial end, the rolling planetary bodies and ring gear sections supported by the spindle between the first axial end and the second axial end such that the spindle extends entirely through the rolling planetary bodies, the ring gear sections and the piston, the spindle connected with the rotor towards the first axial end and the second axial end being a free end which extends away from the pressure chamber.

2. The hydrostatic actuator as recited in claim 1 further comprising:
an integrated electronic control device for controlling the electric motor;
an attaching device adjacent to the electronic control device for attaching the hydrostatic actuator to a receiving component of the motor vehicle; and
a heat dissipation device situated between the electronic control device and the attaching device.

3. The hydrostatic actuator as recited in claim 1 further comprising:
an integrated electronic control device for controlling the electric motor; and
a rotational angle sensor in the integrated electronic control device; and
at least one magnet for the spindle, an axial position of the at least one magnet being calibratable relative to the spindle.

4. The hydrostatic actuator as recited in claim 1 wherein a pressure equalization of the pressure chamber is provided, the pressure equalization being divided into a reserve chamber in the housing and a storage container connected thereto and situated outside of the housing.

5. The hydrostatic actuator as recited in claim 1 wherein the radial bearing is situated on an end shield which surrounds the stator in a form of a cup.

6. The hydrostatic actuator as recited in claim 5 wherein a radial heat expansion coefficient of the end shield is matched to a radial heat expansion coefficient of the electric motor.

7. The hydrostatic actuator as recited in claim 5 wherein the end shield forms a shielding for an electronic control device for controlling the electric motor.

8. The hydrostatic actuator as recited in claim 5 wherein the stator is rotationally fixed with respect to the end shield, the end shield having a torque support with respect to a housing part connected to the housing.

9. The hydrostatic actuator as recited in claim 1 further comprising an attaching device for joining the hydrostatic actuator to a receiving component, the attaching device being aligned in the same direction as a pressure connection of the pressure chamber.

10. A motor vehicle comprising the hydrostatic actuator as recited in claim 1 .

11. The hydrostatic actuator as recited in claim 3 wherein the integrated electronic control device, the rotational angle sensor and the at least one magnet are provided at the first axial end of the spindle.

12. The hydrostatic actuator as recited in claim 1 further comprising a sensor channel extending parallel to the spindle, the sensor channel being provided with a sensor body extending axially in the sensor channel, the sensor body being fixed to the piston such that the sensor body moves axially in the sensor channel upon axial movement of the piston.

13. The hydrostatic actuator as recited in claim 1 wherein the pressure chamber forms a ring around the ring gear sections and rolling planetary bodies.

14. The hydrostatic actuator as recited in claim 1 further comprising a sliding sleeve fixed to the piston, the ring gear sections being centered within the sliding sleeve.

15. The hydrostatic actuator as recited in claim 14 further comprising a driver disk surrounding the spindle and fixing the sliding sleeve to the piston, the piston extending away from the driver disk toward the electric motor.

16. The hydrostatic actuator as recited in claim 15 wherein the rolling planetary bodies include helically toothed rolling surfaces configured for driving the ring gear sections, which are guided non-rotatably in a linear guide, so that the ring gear sections together with the sliding sleeve are moved axially in a direction of the electric motor and carry the piston by the driver disk, so that the piston plunges toward the electric motor into the pressure chamber, thereby increasing pressure.

17. The hydrostatic actuator as recited in claim 5 wherein an axial force of the rolling planetary transmission while under pressure from the piston is introduced into a rim of the end shield through a pressure disk, situated on the spindle, by a thrust bearing.

18. The hydrostatic actuator as recited in claim 5 wherein the end shield has a floor including a multiple-folded axial extension receiving a support of the spindle with the radial bearing.

19. The hydrostatic actuator as recited in claim 3 wherein the rotational angle sensor is configured for simultaneously detecting a rotational angle of the rotor so that the rotor is configured for serving on the one hand for electronic commutation of the electric motor, and on the other hand for redundant detection of travel of the piston, by taking into account a gear ratio change of the rolling planetary transmission while ignoring slippage.

Assignees

• Franz Viktor
• Ehrlich Matthias
• Esly Norbert
• Gramann Matthias
• Gerhart Juergen
• Botiov Julian
• Schaeffler Technologies Ag

Inventors

• Franz Viktor
• Ehrlich Matthias
• Esly Norbert
• Gramann Matthias
• Gerhart Juergen
• Botiov Julian

Classifications

• F15B7/08

  Input units; Master units · CPC title

• F16D29/005

  with a fluid pressure piston driven by an electric motor · CPC title

• H02K7/06

  Means for converting reciprocating motion into rotary motion or vice versa · CPC title

• F03C1/0607

  Driven means · CPC title

• F16D23/14

  Clutch-actuating sleeves {or bearings}; Actuating members directly connected to clutch-actuating sleeves {or bearings} · CPC title