Actuator-integrated force sensor

• US 20030074977A1
• Filed: 09/09/2002
• Published: 04/24/2003
• Est. Priority Date: 12/07/1999
• Status: Active Grant

• Current Assignee: Pacifica Group Technologies Pty Limited
• Original Assignee: Pacifica Group Technologies Pty Limited
• Inventors: Spriegel, Dieter, Doemens, Guenter, Wuensche, Hans
• Granted Patent: US 6,772,647 B2
• Time in Patent Office: Days
• US Class Current: 73/818
• CPC Class Codes: G01L 1/142 using capacitors
• CPC Class Codes: G01L 5/28 for testing brakes

Abstract

In order to precisely and unambiguously measure braking forces, measurements must be carried out as close as possible to the location where the force is directly introduced onto the brake lining (18). To this end, the invention provides that the deflection ΔZ of the actuator bottom (2) is used as a measured variable for the braking force and that the actuator bottom is correspondingly designed for this purpose. The supporting ring (3) of the actuator (1) rests in an annular manner on the brake lining (18). The braking force (F) is centrically applied to the actuator bottom (2). Various measures are taken in order to eliminate, to the greatest possible extent, the influences of temperature and hysteresis effects as the braking force (F) is converted into a proportional deformation ΔZ.

Claims

1. A force sensor with integrated actuator for measuring force in the force flux with an actuator bottom (2) which is formed transversely with respect to the force flux and on which the force (F) acts centrally, and a supporting ring (3) arranged peripherally on the outer edge of the actuator bottom in the direction of force for transmitting the force (F), the actuator bottom (2) which can be deformed with the force (F) being part of the force sensor and its detectable deformation constituting a measure of the force (F).

2. The force sensor as claimed in claim 1, the deformation being detectable by means of inductive or optical measuring methods or with metallic, piezoresistive or semiconductor strain gauges or with strain sensors with silicon surface micromechanics.

3. The force sensor as claimed in claim 1, the deformation being detectable by means of capacitive measuring methods.

4. The force sensor as claimed in claim 3, a central deflection (Δ

z) of the actuator bottom (2) relative to the actuator edge being detectable by means of a plate capacitor arrangement, composed of an electrode (5) positioned on an electrode mount (7) which is pressed, with spring support, onto a base (14), and a corresponding electrode which is constituted by the actuator bottom (2).

5. The force sensor as claimed in one of the preceding claims, the cross section of the connection between the actuator bottom (2) and supporting ring (3) being reduced by means of an internal peripheral groove (8) so that minimized temperature gradients occur in the direction of force in the actuator bottom.

6. The force sensor as claimed in claim 5, a reduction in the material cross section being provided in order to bring about reduced mechanical coupling between the actuator bottom (2) and supporting ring (3). so that transmission of force from the actuator bottom to the supporting ring is minimized.

7. The force sensor as claimed in one of the preceding claims, the supporting ring (3) having at least one opening.

8. The force sensor as claimed in claim 7, a plurality of openings being distributed uniformly over the circumference of the supporting ring (3).