US 7,451,641 B2Granted

Magnetic transduction sensor device, manufacturing process and detection process therefrom

AssigneeC.R.F. Societa Consortile per Azioni

InventorsDaniele Pullini, Piero Perlo

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Abstract

A magnetic pressure sensor device comprises at least one magnetic layer able to vary a magnetisation associated thereto in response to a pressure (P) exerted thereon. The device comprises a plurality of layers arranged in a stack, the magnetic layer able to vary a magnetisation associated thereto in response to a pressure (P) comprising a free magnetic layer, able to be associated to a temporary magnetisation (MT), the free magnetic layer belonging to said plurality of layers, which further comprises at least a spacer layer and a permanent magnetic layer associated to a permanent magnetisation (MP). The sensor device further comprises a compressible layer and a layer with high magnetic coercivity associated to the plurality of layers.

Claims50

Dependent claims

A magnetic transduction sensor device, of the type comprising at least one magnetic layer configured to determine a variable magnetisation (MF) in response to the variation of a physical quantity (P, T), wherein said device comprises a plurality of layers arranged in a stack, said magnetic layer configured to determine a variable magnetisation (MF), in response to the variation of a physical quantity (P, T) interacting magnetically through said variable magnetisation (MF) with a free magnetic layer, able to be associated with a temporary magnetisation (MT), said free magnetic layer belonging to said plurality of layers, which further comprises at least one spacer layer (13) and a permanent magnetic layer (12) associated to a permanent magnetisation (MP),

wherein said physical quantity (P, T) is a pressure (P) and in that said sensor device further comprises a compressible layer and in that said magnetic layer configured to determine a variable magnetisation (M) in response to the variation of a physical quantity (P, T) comprises a layer with high magnetic coercivity, said compressible layer and layer with high magnetic coercivity being associated with said plurality of layer, and
wherein said compressible layer is obtained by and comprises a polymer, elastomer or gel, which is compressible by applying a pressure and which behaves in resilient fashion.

A magnetic transduction sensor device, of the type comprising at least one magnetic layer configured to determine a variable magnetisation (MF) in response to the variation of a physical quantity (P, T), wherein said device comprises a plurality of layers arranged in a stack, said magnetic layer configured to determine a variable magnetisation (MF), in response to the variation of a physical quantity (P, T) interacting magnetically through said variable magnetisation (MF) with a free magnetic layer, able to be associated with a temporary magnetisation (MT), said free magnetic layer belonging to said plurality of layers, which further comprises at least one spacer layer and a permanent magnetic layer associated to a permanent magnetisation (MP),

wherein said physical quantity (P, T) is a pressure (P) and in that said sensor device further comprises a compressible layer and in that said magnetic layer configured to determine a variable magnetisation (M) in response to the variation of a physical quantity (P, T) comprises a layer with high magnetic coercivity, said compressible layer and layer with high magnetic coercivity being associated with said plurality of layer,
wherein said compressible layer is laid onto the free magnetic layer and said layer with high magnetic coercivity is laid onto said compressible layer (21),
wherein said compressible layer has such an uncompressed thickness (D) as to prevent the layer with high magnetic coercivity from switching the temporary magnetisation (MT) associated with said free magnetic layer,
wherein said layer with high magnetic coercivity is obtained by means of a composite structure comprising magnetic particles contained in a resilient matrix, and wherein said layer with high coercivity contains the compressible layer which is in the form of gel or foam or liquid.

1 more element

Dependencies are inferred from the claim text.

Facts

Application: 10/573,919Filed 29 Sep 2004
Priority: IT TO2003A07743 Oct 2003
Published: US 2007/0035892 A115 Feb 2007
Granted: 18 Nov 2008
Term ends: Not estimatedThe source records don’t support an estimate.

Classification4 codes

B60C 23/0408
Mounted on the wheel or tyre: transmitting the signals by non-mechanical means from the wheel or tyre to a vehicle body mounted receiver
G01P 15/105
With conversion into electric or magnetic values: by magnetically sensitive devices
B60C
Vehicle tyres
G01P
Measuring linear or angular speed, acceleration, deceleration, or shock