WO2020259814A1

WO2020259814A1 - Speed sensor with two hall elements

Info

Publication number: WO2020259814A1
Application number: PCT/EP2019/066924
Authority: WO
Inventors: Artur BARTOSZ; Sönke KÖBKE
Original assignee: Wabco Europe Bvba
Priority date: 2019-06-26
Filing date: 2019-06-26
Publication date: 2020-12-30
Also published as: EP3990929A1

Abstract

The present invention relates to a sensor unit for simultaneously detecting magnetic field modulation inputs from at least two rotating wheels. The sensor unit comprises a permanent magnetic structure comprising a top surface and a bottom surface and at least two integrated circuit devices, wherein each of the at least two integrated circuit devices comprises at least one Hall effect element. The at least two integrated circuit devices are attached to the top and bottom surfaces of the permanent magnetic structure, respectively. In one embodiment, the sensor unit is configured to assist in determining two different wheel speeds using the received magnetic signal inputs (excitation or activation signals) from said at least two wheels.

Description

SPEED SENSOR WITH TWO HALL ELEMENTS

Technical Field of the Invention

The present invention relates to the field of sensors for simultaneously receiving magnetic signal inputs from two wheels using which the respective rotational speed of each of the wheels is detected. In particular, the sensor units of the present invention are configured to detect magnetic field modulation inputs from two rotating wheels. In general parlance, said sensor units may be referred to as rpm sensors where‘rpm’ stands for revolutions per minute. In one embodiment, two magnetic signal inputs from two rotating wheels refer simply to the capability of measuring two different rotational speeds simultaneously.

In particular, the sensor units of the present invention relates to a speed sensor that is configured to measure rotational speeds of two different wheels. In one particular embodiment, the two wheels mentioned are present within a

transmission unit of an automobile, wherein the two wheels are connected to different shafts of said transmission unit. For instance, the wheels can be either toothed or slotted. For another instance, at least one wheel is toothed and the other one is slotted. Regardless of whether said wheels are toothed or slotted, they are required to have means to provide said magnetic activation or excitation signals to the sensor units. Further details on this will be explained in reference to accompanying figures. It can also be understood from this configuration, the sensor unit for simultaneously receiving magnetic signal inputs form two magnetic signal inputs is also present within said transmission unit of the automobile. Background of the Invention

Electronic sensors for measuring rotational speed of a wheel are known. Such electronic sensors typically include a magnetic structure with a Hall effect element. The underlying idea is that when the wheels are rotating, the magnetic flux generated by said magnetic structure is interfered with. This interference from the rotating wheel causes a change in the magnetic flux that is detected by the Hall effect element. The Hall effect element is typically connected with an integrated circuit which, among other functions, transmits the flux change as an electrical signal to, e.g., an electronic control unit (ECU). This ECU is configured to determine the rotational speed of the wheel in the unit of, e.g., revolutions per minute (rpm). One such active speed sensor is disclosed for e.g., in

DE102012012384 A1 assigned to WABCO GmbH where said active speed sensor is also configured to measure speed of a wheel using e.g., teeth or slots of the wheel (see e.g., paragraph [0013] of DE102012012384 A1 ) and is disclosed to be specifically used for brake control systems.

Furthermore, typical electronic sensors for measuring speed of the wheels include a magnetic structure and a Hall-effect sensor chip attached to the magnetic structure. The Hall-effect sensor chip includes a Hall effect element incorporated therein. Such a construction may however be arguably optimal for receiving inputs from one rotating wheel with a toothed configuration. One of the factors that play a critical role in determining whether the Hall-effect sensor is appropriately positioned is the“air gap” between the sensor and the rotating wheel or the tooth of the rotating wheel. General principles of the speed sensors associated with, for instance, any rotating wheel with the teeth can be accessed at:

http://inform.wabco-auto.com/intl/pdf/815/000/163/815_163.pdf , in particular in the section titled“Sensors and Toothed wheels” on pages 39 to 45 from the applicant of the present application. For the sake of illustration a conventional system is disclosed. Fig. 1 and associated description discloses a conventional system 100 for measuring speeds of two wheels. Said system 100 includes a Flail effect element. It is noted that Fig.

1 is merely provided for exemplary illustration of a conventional system 100 and said system is not shown its entirety.

In accordance with conventional system 100, there are two separate Flail effect elements 102 and 104 (see Fig. 1 ) are provided. These two Flail effect elements 102 and 104 include magnetic structures 106 and 108. Two Flail effect elements 102 and 104 are configured to receive signal inputs from rotating wheels 1 16 and 1 18 or detect magnetic field modulation signals from said rotating wheels 1 16 and 1 18, respectively. For instance, magnetic structures 106 and 108 exert magnetic fields within certain range of area surrounding said structures. First magnetic structure 106 is in the vicinity of first rotating wheel 1 16 and second magnetic structure 108 is in the vicinity of second rotating wheel 1 18. It is to be noted that the above-mentioned air gap plays a role in the spatial arrangement of wheels 1 16 and 1 18 and magnetic structures 106 and 108.

During rotation, first rotating wheel 1 16 comprising teeth 1 16a interferes with the magnetic flux generated by first magnetic structure 106. In particular, the flux lines (not shown) are cut by teeth 1 16a during rotation of wheel 1 16. This cutting and/or interferences caused by first rotating wheel 1 16 i.e., its teeth 1 16a are detected by integrated circuit chip 1 10 that is attached to one of the sides of first magnetic structure 106. A similar functioning is also found, for instance, with second rotating wheel 1 18 and second magnetic structure 108 where instead of teeth 1 16a, slots 1 18a in association with bridging material of rotating wheel 1 18 generate or contribute to change in the magnetic flux associated with second magnetic structure 108. In other words, similar to first rotating wheel 1 16, the rotation of second rotating wheel 1 18 also contributes to the cutting and/or interferences in the magnetic flux generated by second magnetic structure 108. Further, it is noted that, this cutting of magnetic flux lines generate electrical signals in integrated circuit chips 1 10 and 1 12. The working of the sensors of the likes is well known in the field of the speed sensors. Typically, rotating wheels 1 16 and 1 18 are made of material that can cut the magnetic flux lines associated with structures 106 and 108 such as ferromagnetic material.

Integrated circuit chips 1 10 and 1 12 are connected with the ECU (not shown in Fig. 1 ) through which the rotational speed of wheels 1 16 and 1 18 are determined using units“rpm” (revolutions per minute).

However, it is potentially problematic when the magnetic flux lines from first magnetic structure 106 interferes with the flux lines of second magnetic structure 108. As would be apparent to a person skilled in the art, such a scenario may be referred to as static magnetic field attenuation caused as a result of overlap of magnetic fields between the two-magnetic structures as present in the

conventional arrangements. The magnetic field attenuation results in, for instance, weaker magnetic signals generated for the speed sensors to detect and read. In other words, there is a possibility of having two competing static magnetic fields overlapping each other resulting in weaker flux lines because of noise. It is also derivable that, because of the noise generated due to competing static magnetic fields, the strength or signal-to-noise-ratio of the recorded signals by the speed sensors are affected.

Summary of the Invention

It follows from the above that one of the technical advantages of the present invention is to avoid a potential or partial cancellation of said two competing static magnetic fields generated by different magnetic structures present within a system or sensor for measuring two different speed values of two rotating wheels. As a consequence, air gap provided between the sensors and the rotating wheels for which the speed measurement to be performed is also affected. It is one of the objectives of the present invention to provide for maximizing the air gap between the sensors and the wheels. The above mentioned technical advantages are achieved through the invention claimed in independent claim 1. Claims dependent on independent claim 1 are provided to encompass further advantageous embodiments of the present invention.

Accordingly, the present invention relates to a sensor unit for simultaneously receiving magnetic signal inputs from at least two rotating wheels. The sensor unit comprises a permanent magnetic structure comprising a top surface and a bottom surface, and at least two integrated circuit devices, wherein each of the at least two integrated circuit devices comprises at least one Hall effect element. The at least two integrated circuit devices are attached to the top and bottom surfaces of the permanent magnetic structure, respectively. One of the technical advantages achieved by placing a single permanent magnetic structure according to the present invention between the two rotating wheels is to enable reception of magnetic signal inputs with an appropriate signal to noise ratio while at the same time achieving the optimum air gap between the said permanent magnetic structure and said at least two rotating wheels.

In an optional embodiment, the sensor unit includes at least one ferrous metal or ferromagnetic concentrator positioned between the top and bottom surfaces of the permanent magnet and the at least two integrated circuit devices. The functional capability and the advantage of the ferromagnetic concentrators is known to the person skilled in the art. Therefore, further discussion of the concentrators is not provided herewith.

In an alternative embodiment, the two integrated circuit devices are directly attached without any intermediary elements to the top and bottom surfaces of the permanent magnet. In such an embodiment, the ferrous metal or ferromagnetic concentrator may be incorporated in other components of the sensor unit such as integrated circuit devices without any contact with the permanent magnetic structure. It is also envisaged in an embodiment, that the sensor unit includes a polymeric cover that is over-molded to the components of the sensor unit. This protects the sensor unit from dust and foreign particles and in general increases the life of the sensor unit.

In accordance with an embodiment, each of the at least two integrated circuit devices is an unbiased Hall integrated circuit. In other words, each of the at least two integrated circuit devices include at least one unbiased Hall effect sensor. When unbiased Hall integrated circuit is used, it provides flexibility regarding the usage of number and/or design of permanent magnets used within the scope of the present invention. Further indirect advantages achieved by using the unbiased Hall integrated circuit includes, flexibility in varying air gaps - a consequence of being able to change the number and/or design of permanent magnets along with or independent of their respective magnetic strengths, different wheel structures of the two rotating wheels (toothed wheel against slotted wheel) etc.,

In accordance with another embodiment, the permanent magnetic structure of the sensor unit is a compound magnetic structure. The compound magnetic structure enables more than mere North-South configuration that is enabled by any single magnetic structure. For instance, a magnetic structure having North-South-North or South-North-South typical compound magnetic structures provides different level of flexibility when it is implemented in real time. For another instance, the compound magnetic structure can mean more than one simple magnetic structure i.e., more than one North-South pole configuration. In general, increase in the sensitivity of rotational speed of wheels because of using compound magnetic structure in the sensor units and other technical advantages are known to a person skilled in the art. In accordance with an alternative embodiment, the permanent magnetic structure is a simple magnetic structure with e.g., a typical North-South or South- North polar configuration. Depending on the application area and use-case scenario, either of the simple or compound magnetic structure can be used. ln accordance with an exemplary embodiment, the at least two integrated circuit chips are connected to an Electronic Control Unit (ECU). Such connections may be enabled by using one or more cables.

In accordance with another embodiment, a transmission unit is provided which comprises the sensor unit as mentioned above. The transmission unit further comprises a first shaft, and a second shaft, wherein the transmission unit includes a first wheel attached to the first shaft and a second wheel attached to the second shaft, and wherein the sensor unit as mentioned above is configured for

simultaneously receiving the magnetic signal inputs from said first wheel and said second wheel, for instance, by using said single permanent magnetic structure.

Further embodiments and their technical advantages are explained in association with the drawings.

Brief description of the accompanying drawings

Fig. 1 shows a conventional system including a Flail- effect element that is used to detect rotational speeds or speed values of two different rotating wheels (see above for further explanation);

Fig. 2 illustrates a sensor unit for simultaneously receiving magnetic signal inputs or detecting magnetic field modulation inputs from two rotating wheels in

accordance with an embodiment of the present invention;

Fig. 3 shows a cross-sectional view of a sensor unit for simultaneously receiving magnetic signal inputs from two rotating wheels in accordance with an embodiment of the present invention; and

Fig. 4 shows a schematic illustration of a transmission unit with for simultaneously receiving magnetic signal inputs or detecting magnetic field modulation inputs from two rotating wheels in accordance with an exemplary embodiment of the present invention. The above figures and associated description provided below are merely for illustrative purposes while the claims appended below are purported to define the scope of the present invention.

Detailed description of the accompanying drawings

Fig. 2 illustrates a sensor unit 200 for simultaneously receiving magnetic signal inputs from two rotating wheels 1 16 and 1 18 in accordance with an embodiment of the present invention. Partial cross section of wheels 1 16 and 1 18 are shown merely for the understanding. For e.g., the magnetic signal inputs may refer to the excitation signals detected by sensor unit 200 in accordance with an embodiment of the present invention.

In accordance with the present embodiment, sensor unit 200 is for simultaneously receiving magnetic signal inputs and/or for simultaneously detecting magnet modulation signal inputs from at least two rotating wheels 1 16 and 1 18. In order to clarify the meaning of the expression“simultaneously receiving” within the context of the present invention, it is noted that the technical meaning of the expression will be understood by the person skilled in the art of“speed sensors”. Nevertheless, said expression is provided to denote the capability of being able to receive the magnetic modulation signal inputs from each of the two wheels at the same time and that too, without missing out on any.

For instance, in accordance with the present application, it is derivable that sensor unit 200 is configured for receiving magnetic excitation or activation signals from two rotating wheels 1 16 and 1 18 at the same time provided they both are rotating or some degree of movement is performed by them. In the same instance, it could also be derived that there are provisions in rotating wheels 1 16 and 1 18 for creating this excitation or activation signals in sensor unit 200. For instance, in first rotating wheel 1 16 includes teeth 1 16a and in second rotating wheel intermittent arrangement of slots 1 18a (or bridging material adjacent to slots 1 18a) causes said excitation or activation signals in sensor unit 200. In principle, the magnetic flux lines generated by a magnetic structure 202 has to be interfered with or cut by teeth or other means provided on wheels 1 16 and 1 18 (see further explanation in the background section for general principle of working of such an arrangement). In general, sensor unit 200 is configured to assist in determining two different wheel speeds using the received magnetic signal inputs (excitation or activation signals) from wheels 1 16 and 1 18. As also mentioned before, sensor unit 200 assists in determining two different wheels speeds by firstly detecting magnetic field modulation inputs from said two rotating wheels 1 16 and 1 18.

Accordingly, the present invention, in accordance with the present embodiment, provides sensor unit 200 comprising a permanent magnetic structure 202 comprising a top surface 202a and a bottom surface 202b. For instance, permanent magnetic structure 202 in accordance with an application can be a compound magnetic structure. The compound magnetic structure enables more than mere North-South configuration that is enabled by any single magnetic structure. For instance, a magnetic structure having North-South-North or South- North-South typical compound magnetic structures provides different level of flexibility when it is implemented in real time. For another instance, the compound magnetic structure can mean more than one simple magnetic structure i.e., more than one North-South pole configuration. In general, increase in the sensitivity of rotational speed of wheels because of using compound magnetic structure in the sensors and other technical advantages are known to a person skilled in the art. In accordance with an alternative embodiment, the permanent magnetic structure is a simple magnet with e.g., a typical North-South or South-North polar configuration.

In accordance with the present embodiment, sensor unit 200 comprises only one permanent magnetic structure 202 or a single permanent magnetic structure 202 and no more. In other words, sensor unit 200 does not comprise or include or consist of further or any additional magnetic structure of the nature of permanent magnetic structure 202 apart from said permanent magnetic structure 202, which is one of the salient features of the present invention. In order to positively define this feature of the present invention, it is noted the sensor unit 200 consists of single permanent magnetic structure 202 through which the technical function of simultaneously detecting magnetic field modulation inputs from at least two rotating wheels e.g., 1 16 and 1 18 is facilitated.

Sensor unit 200 is also comprised of first and second integrated circuit devices 204 and 206, wherein each of the at least two integrated circuit devices 204 and 206 comprises at least one Hall effect element (not shown in the figures). It is noted that only two integrated circuit devices 204 and 206 are provided for illustration. However, the possibility of more than two integrated circuit devices being attached to permanent magnetic structure 202 is not excluded which, for instance, may be useful in applications where the speeds of more than two rotating wheels are to be measured.

In an exemplary embodiment, said Hall effect element includes a linear Hall voltage amplifier and/or Schmitt trigger circuit. Such features of Hall effect element or Hall effect elements themselves incorporated in integrated circuit devices 204 and 206 are quite known to a skilled person in the field of the speed sensors.

Therefore, no further explanation is provided herewith.

Furthermore, in accordance with this embodiment, at least two integrated circuit devices i.e., a first and second integrated circuit devices 204 and 206 are attached to the top and bottom surfaces (see reference signs‘202a and‘202b’ of Fig. 3) of permanent magnetic structure 202, respectively. In certain embodiments of the present invention, optionally, at least one ferromagnetic or ferrous concentrator 302 and 304 is provided between integrated circuit devices 204 and 206 and top and bottom surfaces 202a and 202b magnetic structure 202. In other embodiments of the present invention, integrated circuit devices 204 and 206 are directly attached to magnetic structure 202, in particular at its top and bottom surfaces 202a and 202b.

In an exemplary embodiment of the present invention, sensor unit 200 includes a polymer cover 200a that is assembled via over-molding said cover 200a over the components of sensor unit 200.

In accordance with an embodiment of the present invention, each of first and second integrated circuit devices 204 and 206 is an unbiased Hall integrated circuit device. In other words, each of the two integrated circuit devices 204 and 206 include at least one unbiased Hall effect sensor. Even though not shown, integrated circuit devices 204 and 206 are connected to the Electronic Control Unit (ECU), in accordance with an embodiment. The ECU then processes the signals received from integrated circuit devices 204 and 206 to determine the rotational speed of wheels 1 16 and 1 18. In the same embodiment, wheels 1 16 and 1 18 are attached to two different shafts of a transmission unit (not shown). For instance, one of the shafts could be mentioned as a main shaft and another one could be mentioned as a counter shaft.

Fig. 3 shows a cross-sectional view of sensor unit 200 for simultaneously receiving magnetic signal inputs or detecting magnetic field modulation inputs from two rotating wheels 1 16 and 1 18 in accordance with an embodiment of the present invention. While the rotating wheels 1 16 and 1 18 are same as the embodiment associated with Fig. 2, the cross-sectional view is provided merely for illustration.

The cross-sectional view shows how sensor unit 200 is spatially arranged between two rotating wheels 1 16 and 1 18 for the sake of illustration.

As mentioned above, two wheels 1 16 and 1 18 may be attached to two different shafts within, for instance, a transmission unit (not shown) of a vehicle. First wheel 1 16, for instance, utilizes teeth 1 16a for creating magnetic activation signals or excitation signals in sensor unit 200, in particular in first integrated circuit device 204. Second wheel 1 18, for instance, utilizes slots 1 18a for creating magnetic activation signals or excitation signals in sensor unit 200, in particular in second integrated circuit device 206. In an exemplary embodiment, first wheel 1 16 is attached to a main shaft (not shown) of the transmission unit that receives the work input directly or indirectly from an engine crank shaft (not shown). In the same exemplary embodiment, second wheel 1 18 is attached to a counter shaft (not shown), which, for instance, may be driven by or operably connected to said main shaft of the transmission unit (not shown). In another exemplary embodiment, first wheel 1 16 is attached to the counter shaft and second wheel is attached to the main shaft.

Further, as shown in both Figs. 2 and 3 of the present application, sensor unit 200 includes terminals 208 which are connected to the ECU (not shown). For instance, one or more cables may connectively extend from terminals 208 to transmit electrical signals from sensor unit 200 to the ECU. Needless to mention, the ECU could be connected to further or additional ECUs present within the vehicle through cable or in a wireless manner via CAN (Control Area Network) protocol.

Finally, for instance, a longitudinal axis 306 in Fig. 3 is provided to illustrate a spatial and/or longitudinal orientation of permanent magnetic structure 202 of sensor unit 200 in reference to wheels 1 16 and 1 18. This is, however, provided only for illustration based on, for instance, magnetic field strength of permanent magnetic structure 202. In accordance with an embodiment, permanent magnetic structure 202 is configured such that it can be positioned between two wheels 1 16 and 1 18 whose respective rotational speeds are to be measured so that the magnetic field modulation inputs are received from said wheels 1 16 and 1 18 either intermittently and/or periodically. This is one of the exemplary characteristics of magnetic structure 202 i.e., its spatial and/or longitudinal orientation with respect to wheels 1 16 and 188 that enables sensor unit 200 simultaneously detecting magnetic field modulation inputs from two rotating wheels 1 16 and 1 18. Fig. 4 shows a schematic illustration of a transmission unit 400 with sensor unit 200 in accordance with an exemplary embodiment of the present invention. Said transmission unit 400 is connected to an output of an engine (not shown) of a vehicle 400a via a first shaft 402. In this embodiment, transmission unit 400 could be a gear box of vehicle 400a.

For instance, first shaft 402 may be operably connected to a crank shaft of the engine. First shaft 402 can also be called as the main shaft. In the present example, first shaft 402 includes two wheels - a first wheel 406 and a second wheel 408. Transmission unit 400 includes a second shaft 404 or can alternatively be named as a counter shaft which is attached to a third wheel 410 and a fourth wheel 412. It is noted that second wheel 408 and fourth wheel 412 can be toothed or slotted or one of them can be toothed while the other one is slotted (structurally similar to wheels 1 16 and 1 18 discussed above). In order to measure the rotational speeds of second and fourth wheels 408 and 412, speed sensor unit 200 or sensor unit 200 for simultaneously receiving magnetic signal inputs or detecting magnetic field modulation inputs from two rotating wheels 408 and 412 is provided. In another embodiment, sensor unit 200 can be provided alongside any of the two rotating wheels of the transmission unit 400 whose rotation speed needs be measured.

It is noted that, for instance, at least wheels 408 and 412 are configured to linearly translate along shafts 402 and 404. In another instance, all wheels 406, 408, 410 and 412 are configured to linearly translate along shafts 402 and 404. Arrow marks 414 and 416 are provided to show the movement that gears 408 and 412 are capable of undertaking.

Furthermore, the transmission unit 400 is operatively coupled to a transmission or gear box actuator 418 that is configured to facilitate linear translatory motion of wheels 406 to 412 along shafts 402 and 404. This may be achieved using, for e.g., forks that catch wheels 406 to 412 (not shown) and move them along shafts 402 and 404.

In the same embodiment, it is envisaged that sensor unit 200 is connected to an Electronic Control Unit (ECU) 420. Similarly, transmission actuator 418 is also connected to said ECU 420 from which it receives such as instructions to shift the positions of e.g., wheels 408 and 412 along shafts 402 and 404. By this manner, different wheels from one shaft are engaged with different wheels on another shaft within transmission unit 400. It is also recognizable that number of wheels and shafts are provided merely for illustration and can vary. Function and structure of transmission unit 400 can also vary based on the type and manufacturer of said transmission unit 400 or said vehicle 400a.

Furthermore, it is explicitly mentioned herewith that the example of transmission unit 400 of the vehicle 400a is merely mentioned for the illustration of one of the application areas of the sensor unit 200 of the present invention. It is noted that the sensor unit 200 can be used in any arrangements that uses two different wheels and where there is a need to measure the respective rotational speeds of the two wheels, for instance, simultaneously. As is apparent from the illustrations provided in Figs. 2 and 3 of the present invention, wheels 1 16 and 1 18 appear somewhat concentric, but nevertheless their axis of rotation is parallel to each other. Similarly, Fig. 4 shows wheels 406, 408, 410 and 412 whose axes of rotation are also parallel, but not concentric in all cases. Wheels 406 and 408 have axes of rotation that are concentric as they share common shaft 402. Similarly, wheels 410 and 412 are concentric as they have axes of rotation that are concentric as they share common shaft 404. Sensor unit 200 is however shown to be configured to measure the speeds of wheels 408 and 412, which have parallel axes of rotation. This arrangement illustrates one of the practical applications of sensor unit 200 in measuring the speeds of any two wheels simultaneously. Therefore, the

arrangement of wheels 1 16 and 1 18 in Figs. 2 and 3 and the arrangement of wheels 408 and 412 in Fig. 4 should not be considered as limiting the configurations under which sensor unit 200 is capable of functioning. As long as suitable air gap can be established between sensor unit 200 and the wheels whose rotational speeds are to be measured, sensor unit 200 can perform its function of simultaneously detecting magnetic field modulation inputs from said wheels.

List of reference signs (part of the description)

100 - conventional sensor system

102 - first Hall-sensor unit

104 - second Hall-sensor unit

106- first magnetic structure

108- second magnetic structure

1 10- first integrated circuit chip

1 12- second integrated circuit chip

1 14- terminals

1 16- first rotating wheel

1 18- second rotating wheel

200 - sensor unit

200a - polymeric cover

202 - permanent magnetic structure

202a - top surface of the permanent magnetic structure

202b - bottom surface of the permanent magnetic structure

204 - first integrated circuit device

206 - second integrated circuit device

208 - terminals

302 - a first ferromagnetic concentrator - a second ferromagnetic concentrator

- longitudinal axis

- transmission unit

a - vehicle

- first shaft

- second shaft

- first wheel

- second wheel

- third wheel

- fourth wheel

- arrow mark to show linear translator movement of second wheel 408 - arrow mark to show linear translator movement of fourth wheel 412 - transmission or gear box actuator

- Electronic Control Unit (ECU)

Claims

1 . A sensor unit (200) for simultaneously detecting magnetic field modulation inputs from at least two rotating wheels (1 16, 1 18, 408, 412), comprising: a permanent magnetic structure (202) comprising a top surface (202a) and a bottom surface (202b); and

at least two integrated circuit devices (204, 206), wherein each of the at least two integrated circuit devices (204, 206) comprises at least one Hall effect element,

characterized in that,

the at least two integrated circuit devices (204, 206) includes a first integrated circuit device (204) is attached to the top surface (202a) and a second integrated circuit device (206) is attached to the bottom surface (202b) of the permanent magnetic structure (202), respectively.

2. The sensor unit (200) of claim 1 , wherein the sensor unit (200) includes at least one ferrous metal or ferromagnetic concentrator (302; 304) positioned between the top and bottom surfaces (202a, 202b) of the permanent magnetic structure (202) and the at least two integrated circuit devices (204, 206) .

3. The sensor unit (200) of claim 1 , wherein the two integrated circuit devices (204, 206) are directly attached without any intermediary elements to the top and bottom surfaces (202a, 202b) of the permanent magnetic structure (202).

4. The sensor unit (200) of any one of the above mentioned claims, wherein the sensor unit (200) includes a polymeric cover (200a) that is assembled via over-molding said cover (200a) over components of the sensor unit (200).

5. The sensor unit (200) of any one of the above-mentioned claims, wherein each of the at least two integrated circuit devices (204, 206) includes an unbiased Hall effect sensor.

6. The sensor unit (200) of any one of the above-mentioned claims, wherein the permanent magnetic structure (202) is either a simple or a compound magnetic structure.

7. The sensor unit (200) of any one of the above-mentioned claims, wherein the at least two integrated circuit devices (204, 206) are connected to an Electronic Control Unit (ECU).

8. The sensor unit (200) of any one of the above-mentioned claims, wherein the sensor unit (200) is configured to assist in determining two different wheel speed values using the detected magnetic modulation inputs from said at least two rotating wheels (1 16, 1 18).

9. A transmission unit (400) for a vehicle (400a), comprising the sensor unit (200) as claimed in any one of the claims 1 to 8;

a first shaft (402); and

a second shaft (404);

wherein the transmission unit (400) includes a first wheel (406;408) attached to the first shaft (402) and a second wheel (410; 412) attached to the second shaft (404).