Method for manufacturing a sensorized braking element, in particular a brake pad and a sensorized brake pad obtained thereby

Patent metadata

Field	Value
Publication number	US-11168752-B2
Application number	US-201816173355-A
Country	US
Kind code	B2
Filing date	Oct 29, 2018
Priority date	Sep 8, 2014
Publication date	Nov 9, 2021
Grant date	Nov 9, 2021

Abstract

A method in which at least one piezoceramic sensor and an electric circuit to collect an electric signal emitted by the piezoceramic sensor when subjected to a mechanical stress and possibly processing it are made as an electrically insulated unit. The unit is equipped with at least a branching ending with respective electric contacts and having the connected at least one piezoelectric sensor. The electric circuit and the at least one sensor are mechanically fixed integral with a first surface of a supporting metal element of a brake pad. Branching is formed so as to position the at least one piezoelectric sensor at a predetermined point of the first surface.

First claim

The invention claimed is:

1. A method for making sensorized brake elements for vehicles, the brake element having a supporting metal element and a friction material block formed on a first surface of the supporting metal element, the method comprising:
integrating at least one piezoceramic sensor directly on the first surface of the supporting metal element, wherein the at least one piezoceramic sensor self-generates an electric signal when subjected to a mechanical stress;
integrating an electric circuit directly on the first surface of the supporting metal element, the electric circuit configured for capturing the self-generated electric signal from the at least one piezoceramic sensor;
wherein the at least one piezoceramic sensor and electric circuit are integrally fixed to the first surface of the supporting metal element and embedded within the friction material block; and
providing the first surface of the supporting metal element with at least one seat for the at least one piezoceramic sensor, the at least one seat having a first recess having a depth of substantially an order of magnitude smaller than a thickness of the at least one piezoceramic sensor measured perpendicular to the first surface.

2. The method according to claim 1 , in which the electric circuit is made as an electrically insulated unit having at least one branching ending with respective electric contacts, the method further comprising:
electrically and mechanically connecting the at least one piezoceramic sensor to the electric contacts arranges at an end of the at least one branching; and
configuring the branching to enable the at least one piezoceramic sensor to be positioned at a predetermined point on the first surface of the supporting metal element.

3. The method according to claim 2 , further comprising:
providing the at least one seat with at least one groove-shaped second recess for housing the electric circuit and the at least one branching thereof substantially flush with the first surface.

4. The method according to claim 3 , in which the first and second recesses are formed by one of a machining tool, laser or fine blanking of the supporting metal element.

5. The method according to claim 2 , further comprising:
integrally fixing the at least one piezoceramic sensor to the first surface of the supporting metal element by gluing and electrically connecting the at least one piezoceramic sensor to at least one of the electric contacts by wire bonding.

6. The method according to claim 3 , further comprising:
making the electric circuit from respective conductor cables electrically insulated from each other and from the supporting metal element in which the conductor cables are electrically connected with the electric contacts, and
arranging the electric contacts within respective grooves of the supporting metal element identified by the at least one second recess.

7. The method according to claim 3 , further comprising:
defining the electric circuit by a plurality of electrically conductive tracks that are electrically insulated from each other and the supporting metal element, each of the conductive tracks ending towards the at least one piezoceramic sensor with at least one electric contact electrically and mechanically connected with the at least one piezoceramic sensor, at least one pair of the conductive tracks defining one said branching.

8. The method according to claim 7 , wherein the electric circuit with the electrically conductive tracks, the electric contacts and respective electrically insulating layers over and below the conductive tracks are directly obtained by screen printing over the first surface of the supporting metal element, inside the at least one second recess, the method further comprising:
electrically and mechanically connecting a first contact of a first said conductive track to a first face of the at least one piezoceramic sensor, and a second contact of a second said conductive track and obtained in a position immediately adjacent to and coplanar with the first contact is connected to a second face of the at least one piezoceramic sensor, opposite the first face, by wire-bonding, or to a different portion of the first face of at least one said piezoceramic sensor having built up electrodes.

9. The method according to claim 7 , in which the electric circuit with the conductive tracks, and the electric contacts are obtained by screen printing, over a first electrically insulating polymeric layer, said first polymeric layer being made of a polyimide and subsequently covering at least the conductive tracks with a second electrically insulating polymeric layer, said second polymeric layer being made of a polyimide, so as to form an electrically insulated self-supporting unit;
the self-supporting unit being subsequently glued directly over the first surface of the supporting metal element and finally the at least one piezoceramic sensor being mechanically and electrically connected with a first contact of a first said conductive track and with a second contact of a second said conductive track obtained in a position immediately adjacent to and coplanar with the first contact, arranging a first face of the at least one piezoceramic sensor against the first contact and folding the second contact onto the first contact and against a second face of the at least one sensor opposite the first face, with the at least one piezoceramic sensor being sandwiched between the first and the second contact; or connecting the second contact with the second face of the at least one piezoceramic sensor by means of wire bonding; the at least one piezoceramic sensor being finally coated with an electrically insulating layer.

10. The method according to claim 1 , further comprising:
providing a shallow recess is provided on an edge of the supporting metal element arranged on the opposite side of the at least one branching of the electric circuit, and
configuring the shallow recess for the receipt of an electric connector, which is electrically connected to the electric circuit.

11. A sensorized brake element comprising:
a supporting metal element;
a damping and a thermally insulating layer arranged on a side of a first surface of the supporting metal element;
a friction material block integrally supported by the supporting metal element on the side of the first surface and above the damping and thermally insulating layer;
at least one piezoceramic sensor below the damping and electrically insulating layer and fixed directly over the first surface of the supporting metal element, the at least one piezoceramic sensor designed to self generate an electric signal when subjected to a mechanical stress;
an electric circuit configured to capture the electric signal, wherein the electric circuit is made as an electrically insulated unit having at least one branching ending with respective electric contacts to which the at least one piezoceramic sensor is mechanically and electrically connected, and wherein the least one piezoceramic sensor is embedded in the friction material block with the interposition of the damping and thermally insulating layer; and
at least one seat provided on the first surface of the supporting metal element for the at least one piezoceramic sensor, the at least one seat having a first recess having a depth of substantially an order of magnitude smaller than a thickness of the at least one piezoceramic sensor measured perpendicular to the first surface.

12. The sensorized brake element according to claim 11 , in which the electric circuit and the at least one piezoceramic sensor are mechanically and integrally fixed to the first surface and the at least

Assignees

• Itt Italia Srl

Inventors

• Merlo Fabrizio
• Martinotto Luca
• Solari Mattia
• Donzelli Daniele

Classifications

• F16D2129/12

  Electrostrictive or magnetostrictive elements, e.g. piezoelectric · CPC title

• F16D2066/005

  Force, torque, stress or strain · CPC title

• F16D66/00

  Arrangements for monitoring working conditions, e.g. wear, temperature · CPC title

• F16D65/092 Primary

  for axially-engaging brakes, e.g. disc brakes · CPC title

• F16D65/097

  Resilient means interposed between pads and supporting members {or other brake parts} · CPC title