Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
  • B60C23/00—Devices for measuring, signalling, controlling, or distributing tyre pressure or temperature, specially adapted for mounting on vehicles; Arrangement of tyre inflating devices on vehicles, e.g. of pumps or of tanks; Tyre cooling arrangements
  • B60C23/02—Signalling devices actuated by tyre pressure
  • B60C23/04—Signalling devices actuated by tyre pressure mounted on the wheel or tyre
  • B60C23/0408—Signalling devices actuated by tyre pressure mounted on the wheel or tyre transmitting the signals by non-mechanical means from the wheel or tyre to a vehicle body mounted receiver
  • B60C23/0422—Signalling devices actuated by tyre pressure mounted on the wheel or tyre transmitting the signals by non-mechanical means from the wheel or tyre to a vehicle body mounted receiver characterised by the type of signal transmission means
  • B60C23/0433—Radio signals
  • B60C23/0447—Wheel or tyre mounted circuits
  • B60C23/0452—Antenna structure, control or arrangement
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
  • B60C23/00—Devices for measuring, signalling, controlling, or distributing tyre pressure or temperature, specially adapted for mounting on vehicles; Arrangement of tyre inflating devices on vehicles, e.g. of pumps or of tanks; Tyre cooling arrangements
  • B60C23/02—Signalling devices actuated by tyre pressure
  • B60C23/04—Signalling devices actuated by tyre pressure mounted on the wheel or tyre
  • B60C23/0491—Constructional details of means for attaching the control device
  • B60C23/0496—Valve stem attachments positioned outside of the tyre chamber

Definitions

• the present invention relates to a microantenna which can be used particularly, but not exclusively, in a transmitter device for monitoring the pressure of a tire of a motor vehicle.
• One object of the present invention is to provide an improved microantenna which can be simply and economically manufactured and which has characteristics including limited dispersion and good stability over time.
• microantenna comprising:
• a support structure including an annular member of an electrically insulating material, in an external surface of which there is provided a helical groove, and to which a circuit board is coupled, which extends in a plane orthogonal to the axis of the annular member, at one end thereof;
• a wire of an electrically conducting material wound in the groove of the annular member, and having a first end which engages holding means of the annular support member, and a second end which is fastened to the circuit board.
• the present invention also proposes a radio transmitter device, particularly a device for monitoring the pressure in a tire of a motor vehicle, comprising a microantenna having the characteristics defined above.
• this radio transmitter comprises
• a mass of an electrically insulating sealing material which incorporates the circuit board in such a way as to leave the transducer uncovered, and which incorporates further a portion of the antenna adjacent to the board, and preferably at least part of the battery, in such a way that the antenna, the board and the battery form a monolithic assembly.
• a radio transmitter of this type also comprises a supporting casing which has an opening that can be coupled pneumatically to an inflating valve of a tire, the casing housing the aforesaid monolithic assembly including the antenna, the circuit board and the battery, in such a way that the opening of the casing is in pneumatic communication with a region which the pressure transducer faces.
• Figure 1 is a sectional view of a device for monitoring the pressure in a tire of a motor vehicle, comprising a microantenna and a radio transmitter according to the present invention
• Figure 2 is a perspective view which shows an annular support member and an associated wire of electrically conducting material for an antenna according to the present invention
• Figure 3 is a perspective view which shows a radio transmitter including an antenna according to the invention.
• Figure 4 is a sectional view taken along the line IV-IV of Figure 3.
• the number 1 indicates the whole of a device for monitoring the pressure (and possibly also the temperature) of a tire of a motor vehicle.
• the device comprises an extension tube 2, made of metallic material for example, a first end 2a of which can be coupled sealingly to the mouth of an inflating valve of a tire, while its other end 2b is provided with a removable plug 3 for sealed closing.
• extension tube 2 there is formed an axial conduit 4, which during use is in pneumatic communication with the inside of the tire with which the device 1 is associated.
• the intermediate portion of the extension tube 2 has a projecting lateral formation 5, in which is formed a transverse passage 6 in communication with the conduit 4.
• the extension tube 2 is laterally connected, by welding for example, to a support casing indicated as a whole by 7.
• this support casing comprises an essentially cup-shaped member 8, made of metallic material for example, which in its base wall has an opening 8a into which the formation 5 of the extension tube 2 sealingly extends.
• the cup-shaped body 8 is coupled to a body 9 essentially in the form of an inverted socket. In the illustrated exemplary embodiment, the mouth of the body 8 is turned down on to the body 9.
• the assembly 1 1 includes an antenna 12 with a circuit board 13 and a voltage supply battery 14.
• the antenna 12, the circuit board 13 and the battery 14 are conveniently incorporated, at least partially, by moulding into a mass 15 of an electrically insulating sealing, and possibly vibration damping, material.
• the antenna 12 which, owing to its small dimensions, is also termed a “microantenna” herein, comprises a support structure which includes an annular member 16 of electrically insulating material, coupled to the circuit board 13.
• the annular member 16 has a helical groove 17 in its outer lateral surface, a wire 18 of electrically conducting material, preferably tinned copper, being wound in this groove.
• the conducting wire 18 forms the radiating member of the antenna, and has a first end 18a ( Figures 2 and 3) bent in an approximately radial direction and engaged and retained by a holder 19 which is conveniently made in one piece with the annular support member 16.
• the other end of the conducting wire 18, indicated by 18b in Figures 2 and 3, is bent in a direction at least approximately parallel to the axis of the annular member 16, and extends through a corresponding through hole formed in the circuit board 13 ( Figure 3), to which it is fixed, by soldering for example.
• the annular support member 16 has in its lower part a pair of sprung appendages 20, with retaining catches 20a at their distal ends (Figure 2). These appendages 20 engage in corresponding peripheral recesses 13a of the circuit board 13 ( Figure 3), by means of their catches 20a which engage under the board.
• the circuit board 13 carries an electrical pressure transducer indicated by 21, and possibly also a temperature sensor, on its upper face.
• the board 13 also carries a plurality of further electrical and/or electronic components, indicated as a whole by 22.
• Conducting strips 24 for the connection of the battery 14 are also connected to the board 13.
• the mass 15 of electrically insulating material incorporates the lower portion of the antenna 12, the circuit board and the components of the latter - with the exception of the pressure transducer 21, as stated above - and at least a part of the battery 14.
• the assembly 1 1 formed in this way can be handled individually and can easily be mounted in the region or chamber 10 formed in the support casing 7 ( Figure 1).
• the arrangement is such that the portion of the region 10 located above the pressure transducer 21 is in pneumatic communication with the passage 6 of the extension tube 2, and therefore with the conduit 4 formed in this tube.
• the transducer 21 is capable of generating electrical signals indicating the pressure in the tire with which the monitoring device 1 is associated for operation. These signals are processed by the devices 22 carried on the circuit board 13, and are transmitted by the antenna 12 to a receiving, processing and control device mounted on board the motor vehicle.
• a resilient ring seal 25 (Figure 1) is positioned in an outer annular recess 26 of the body 9, so as to be radially compressed between the body 9 and the lateral wall of the body 8. This resilient ring seal 25 prevents the pneumatic communication of the passage 6 with the region in which the pressure transducer, and the temperature transducer, if used, are not present.
• the annular support member 16 is made individually by moulding a plastic material having a predetermined dielectric constant.
• the method of individual moulding is preferable to the method of producing the annular support member by cutting from an insulating tube, since it provides greater precision and reproducibility of dimensions.
• the winding of the conducting wire 18 in the groove of the annular support member 16 provides greater dimensional stability and less dispersion of the characteristics of the antenna compared with solutions using free spiral wire in air. Additionally, greater dimensional stability of the conducting wire 18 is provided throughout the service life of the device, even in the presence of high mechanical stresses.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Measuring Fluid Pressure (AREA)
• Arrangements For Transmission Of Measured Signals (AREA)

Applications Claiming Priority (2)

Publications (1)

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Family Applications (1)

Country Status (2)

Cited By (1)

Citations (5)

• 2010
  • 2010-12-17 IT ITTO2010A001009A patent/IT1403407B1/it active
• 2011
  • 2011-12-16 WO PCT/IB2011/055745 patent/WO2012080991A1/en active Application Filing

Patent Citations (5)

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