Tire pressure sensor, antenna apparatus for tire pressure sensor, and tire pressure sensor arrangement

Abstract

The present invention provides a tire pressure sensor and a corresponding antenna apparatus for a tire pressure sensor arrangement. The tire pressure sensor is equipped with: a tire pressure sensing device (IC) for sensing at least one tire pressure parameter and for wirelessly transmitting the sensed tire pressure parameter or a tire pressure parameter based thereon; an antenna device (A), connected to the tire pressure sensing device (IC), for emitting an electromagnetic transmission signal (F) corresponding to the tire pressure parameter or to the tire pressure parameter based thereon; and a circuit board device (CB1) on which the tire pressure sensing device (IC) and the antenna device (A) are arranged. The circuit board device (CB1) has a first region (1a) and a second region (1b), which is bent away from the first region (1a), the first region (1a) can be applied to a rim inner side (I) in such a way that the second region (1b) is spaced apart from the rim inner side (I), and the antenna device (A) is situated substantially in the second region (1b).

Description

[0001] Description

[0002] title

[0003] Tire pressure sensor, antenna device for tire pressure sensor and tire pressure sensor assembly

[0004] State of the art

[0005] The present invention relates to a tire pressure sensor, an antenna device for a tire pressure sensor and a corresponding tire pressure sensor arrangement.

[0006] Since 2014, according to ECE-R 64, all new cars must be equipped with a tire pressure monitoring system (TPMS), which, among other things, helps to prevent accidents caused by incorrect tire pressure or slow leaks. However, optimal tire pressure primarily saves fuel and avoids unnecessary tire wear.

[0007] The car manufacturers use either direct tire pressure sensors in the wheel or indirect tire pressure sensors that evaluate the rolling behavior of the tires.

[0008] Direct-measuring TPMS uses tire pressure and temperature sensors on each individual wheel, which are in direct contact with the air inside the tire. These sensors determine the relevant physical parameters in real time and transmit them telemetrically to the corresponding control unit in the vehicle. The tire pressure sensors receive the necessary electrical power from integrated batteries, which need to be replaced after approximately six to ten years. These tire pressure sensors are typically mounted very close to the rim, either directly on the rim or on a tire pressure monitoring valve, which is also mounted on the rim. Rims are usually made of metal, meaning they significantly and negatively affect the radiation of the high-frequency signal from a tire pressure sensor. The closer the transmitting antenna is to the metallic rim, the weaker the tire pressure sensor's antenna becomes.

[0009] In printed circuit board technology, flexible printed circuit boards (PCBs) or rigid-flex PCBs are well-known. These consist of a rigid, flat circuit board and one or more rigid-flexible sections that can be bent. This allows for the cost-effective realization of non-planar structures.

[0010] US Patent 6,958,684 B2 discloses a pressure transducer arrangement that can be mounted inside a tire to detect the pressure of a fluid in the tire, comprising a sensor housing with a first compartment that is in fluid communication with the fluid, a printed circuit board that is slidably engaged with and removable from the sensor housing, wherein the printed circuit board separates a second compartment from the first compartment.

[0011] The pressure transducer arrangement further comprises a circuit arrangement including a transceiver circuit arranged on the printed circuit board and operationally connected to the pressure transducer, a pressure transducer operationally connected to the circuit arrangement, the pressure transducer being in fluid communication with the first chamber, a coil antenna operationally connected to the transceiver circuit, the antenna being configured to receive a signal from a remote location, the antenna being a track coil arranged on at least two layers of the multilayer printed circuit board, each track coil being wound on a corresponding layer in a substantially helical configuration, each track coil being connected in series on the corresponding layer to an adjacent track coil arranged on an adjacent layer, and a detachable power source.which is connected to the circuit contained in the second compartment; and a cover that is sealed to the housing and the circuit board so that the second chamber is not in fluid contact with the first chamber.

[0012] US 2021 / 0013624 A1 describes an antenna module comprising a rigid substrate, an integrated circuit (IC) arranged on the rigid substrate, a first antenna arranged on the rigid substrate and connected to the IC, a flexible substrate, and a second antenna arranged on the flexible substrate and connected to the IC.

[0013] Disclosure of the invention

[0014] The present invention provides a tire pressure sensor according to claim 1 and a corresponding antenna device for a tire pressure sensor according to claim 8 as well as a corresponding tire pressure sensor arrangement according to claim 10.

[0015] The underlying idea of ​​the present invention is that the antenna device is implemented on a flexible printed circuit board or a rigid-flex printed circuit board in order to gain distance between the transmitting antenna and the rim.

[0016] The rest of the electronic circuitry is implemented, for example, on the rigid part of the circuit board. Bending the flexible part of the circuit board significantly improves the antenna's radiation output.

[0017] Bending upwards can be achieved, for example, by bending the flexible circuit board section upwards from a housing wall, thereby supporting it. A suitable housing design, such as a partition or post, can then fix and align the bent circuit board section.

[0018] This design can be implemented more cost-effectively than soldering a stamped metal antenna onto the circuit board, especially considering the mechanical stresses within a wheel. There is no failure-prone interface in the assembly and connection technology. According to a preferred embodiment, the tire pressure monitoring device is at least partially located in the first area. This allows for efficient use of the available space.

[0019] According to another preferred development method, the first area is essentially planar. This allows for good adhesion to the inside of the rim.

[0020] According to a further preferred embodiment, the printed circuit board (PCB) device is a rigid-flex PCB device which has a permanent bending point between the first and second areas. This allows the bending point to be maintained stably.

[0021] According to a further preferred embodiment, the printed circuit board (PCB) assembly is a flexible PCB assembly which has a bending point between the first and second sections, which is fixed by a support device. This is a cost-effective alternative to the rigid-flex PCB assembly.

[0022] According to a further preferred embodiment, a housing device is provided which has a bottom wall, a side wall and a top wall, wherein the bottom wall can be applied to the inside of the rim and wherein the support structure is formed by the side wall. This enables a stable construction.

[0023] According to a further preferred development, the second area has a concave curvature which, when the first area is applied to the inside of the rim, is directed away from the inside of the rim.

[0024] The present invention will be explained in more detail below with reference to the exemplary embodiments shown in the schematic figures. These show:

[0025] Fig. 1 a), b) shows a first embodiment of the present invention, wherein Fig. 1 a) shows a tire pressure sensor arrangement and Fig. 1 b) shows the associated pressure sensor;

[0026] Fig. 2a), b) shows a second embodiment of the present invention, wherein Fig. 2a) shows a further tire pressure sensor arrangement and Fig. 1b) shows the associated pressure sensor.

[0027] In the figures of the drawing, identical, functionally equivalent and similarly acting elements, features and components - unless otherwise stated - are each provided with the same reference symbols.

[0028] Fig. 1 a), b) show a first embodiment of the present invention, wherein Fig. 1 a) represents a tire pressure sensor arrangement and Fig. 1 b) represents the associated pressure sensor.

[0029] In Fig. 1 a), reference numeral RS1 denotes a tire pressure sensor, which, according to Fig. 1 b), comprises a tire pressure sensing device IC for sensing at least one tire pressure parameter and for wirelessly transmitting the sensing tire pressure parameter or a tire pressure parameter based thereon. The tire pressure sensing device IC is preferably designed as an integrated circuit, which, for example, comprises a micromechanical pressure sensor.

[0030] The tire pressure monitoring device IC can have an evaluation circuit for generating the modified tire pressure parameter based on the measured tire pressure parameter, e.g. for calibration or to take into account other measured or specified parameters, e.g. temperature, etc.

[0031] Further with reference to Fig. 1 b), an antenna device A connected to the tire pressure sensing device IC is provided for emitting an electromagnetic transmission signal F according to the tire pressure parameter or the tire pressure parameter based thereon.

[0032] The tire pressure monitoring device IC and the antenna device A are arranged in a printed circuit board assembly CB1, wherein the printed circuit board assembly CB1 in this embodiment is a rigid-flex printed circuit board assembly which has a permanent bend between a first area 1 a and a second area 1 b, whereby the second area 1 b is angled from the first area 1 a. Thus, the first area 1 a can be applied to an inner rim surface I of a rim F such that the second area 1 b is spaced apart from the inner rim surface I.

[0033] The tire pressure monitoring device IC is at least partially - in this case completely - arranged on the first area 1 a, which is planar.

[0034] In the present case, the second area 1 b has a concave curvature, which, when the first area 1 a is applied to the inner side of the rim I, is directed away from the inner side of the rim I, so that the distance to the inner wall of the rim increases continuously.

[0035] Since the antenna device A is essentially or in this case completely arranged on the second area 1 b, a significantly improved radiation characteristic for the transmission signal F can be achieved.

[0036] The transmission signal F is wirelessly transmitted to a control unit SG, which is located in an associated motor vehicle and which has a receiving antenna AS for receiving the electromagnetic transmission signal F.

[0037] Figures 2a) and 2b) show a second embodiment of the present invention, wherein Figure 2a) represents a further tire pressure sensor arrangement and Figure 2b) represents the associated pressure sensor. In Figure 2a), reference numeral RS2 denotes a tire pressure sensor which differs from the tire pressure sensor RS1 in its construction.

[0038] In particular, in the second embodiment, the printed circuit board device CB2 is a flexible printed circuit board device which has a bending point between the first area 2a and the second area 2b, which is fixed by a support device SW.

[0039] For this purpose, a housing device G is provided in which the flexible printed circuit board device CB2 is clamped. The housing device G has a bottom wall BW, a side wall SW and a top wall DW, wherein the bottom wall BW can be applied to the inner surface of the rim I and wherein the support device SW is formed by the side wall SW.

[0040] In the second embodiment, the second area 2b also has a concave curvature, which is directed away from the inside of the rim when the first area 2a is applied to the inside of the rim I.

[0041] Otherwise, the second embodiment is constructed analogously to the first embodiment.

[0042] Although the present invention has been described with reference to preferred embodiments, it is not limited to these, but can be modified in many ways.

[0043] In particular, the geometries of the printed circuit board setup and the housing shown can be modified in many ways.

Claims

Claims 1. Tire pressure sensor (RS1; RS2) comprising: a tire pressure sensing device (IC) for sensing at least one tire pressure parameter and for wirelessly transmitting the sensed tire pressure parameter or a tire pressure parameter based thereon; an antenna device (A) connected to the tire pressure sensing device (IC) for emitting an electromagnetic transmission signal (F) corresponding to the tire pressure parameter or the tire pressure parameter based thereon; a printed circuit board device (CB1; CB2) on which the tire pressure sensing device (IC) and the antenna device (A) are arranged; wherein the printed circuit board device (CB1; CB2) has a first area (1a; 2a) and a second area (1b; 2b) which is angled from the first area (1a; 2a); wherein the first area (1 a; 2a) can be applied to an inner rim surface (I) such that the second area (1 b; 2b) is spaced away from the inner rim surface (I);and wherein the antenna arrangement (A) is substantially located on the second area (1b; 2b).

2. Tire pressure sensor (RS1 ; RS2) according to claim 1 , wherein the tire pressure sensing device (IC) is arranged at least partially on the first area (1a; 1 b).

3. Tire pressure sensor (RS1 ; RS2) according to claim 1 or 2, wherein the first region (1a; 2a) is substantially planar.

4. Tire pressure sensor (RS1 ; RS2) according to claim 1 , 2 or 3, wherein the printed circuit board device (CB1 ; CB2) is a rigid-flex printed circuit board device which has a permanent bending point between the first area (1 a; 2a) and the second area (1 b; 2b).

5. Tire pressure sensor (RS1 ; RS2) according to claim 1 , 2 or 3, wherein the printed circuit board device (CB1 ; CB2) is a flexible printed circuit board device which has a bending point between the first area (1a; 2a) and the second area (1 b; 2b) which is fixed by a support device (SW).

6. Tire pressure sensor (RS1 ; RS2) according to claim 5, wherein a housing device (G) is provided which has a bottom wall (BW), a side wall (SW) and a top wall (DW), wherein the bottom wall (BW) can be applied to the inside of the rim (I) and wherein the support device (SW) is formed by the side wall (SW).

7. Tire pressure sensor (RS1 ; RS2) according to one of the preceding claims, wherein the second area (1 b; 2b) has a concave curvature which, when the first area (1a; 2a) is applied to the inner side (I) of the rim, is directed away from the inner side of the rim.

8. Antenna device for a tire pressure sensor (RS1 ; RS2) comprising: a printed circuit board device (CB1 ; CB2) on which an antenna device (A) is arranged; wherein the printed circuit board device (CB1 ; CB2) has a first area (1 a; 2a) and a second area (1 b; 2b) which is angled from the first area (1 a; 2a); wherein the first area (1 a; 2a) can be applied to an inner rim surface (I) such that the second area (1 b; 2b) is spaced apart from the inner rim surface (I); and wherein the antenna device (A) is arranged on the second area (1 b; 2b).

9. Antenna device according to claim 8, wherein the printed circuit board device (CB1 ; CB2) is a rigid-flex printed circuit board device which has a permanent bending point between the first area (1 a; 2a) and the second area (1 b; 2b).

10. Tire pressure sensor arrangement comprising: a tire pressure sensor (RS1 ; RS2) according to one of claims 1 to 7, which is applied to an inner rim surface (I) such that the second area (1 b; 2b) is spaced away from the inner rim surface (I); and a control unit (SG) which is arranged in a motor vehicle and which has a receiving antenna (AS) for receiving the electromagnetic transmission signal (F).

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