TECHNICAL FIELD
The present disclosure relates to the field of non-contact magnetic sensors which are adapted to determine the position of a moving part. More particularly, the present disclosure is related to a Hall element based sensing system for sensing a position of a gear shaft.
BACKGROUND OF THE DISCLOSURE
Currently, position sensors have been widely applied in various industrial fields, e.g., the field of automotive control. Position sensing devices are already known in the art for sensing the position of a gear shaft.
In the prior art, for example, a position sensor for a gearbox position of a motor-driven vehicle which includes a magnetic sensor is known from Patent no. EP3404368. It discloses a sensing system comprising a sensing magnet that is fixedly arranged on the gear shaft and moves with the gear shaft as shown in FIG. 1. The sensing magnet provides the information of the reverse gear position and the forward gear position. Further, in patent no. EP1882871, a gearbox of a motor vehicle is provided with a position sensor as shown in FIG. 2. The position sensor is having a Hall effect component (21) which is able to measure the magnetic field in three orthogonal directions (Bx, By, Bz) to determine the position and the orientation of the target (19) in the space and to deduce the position of the gearbox.
A shortcoming of the magnetic sensor used in both the prior arts mentioned above is associated with the position of the magnet, which is mounted on the selector shaft inside the transaxle. Due to extreme operating temperatures (>150°C) and vibrations, the magnet can dislocate or get demagnetized. Further, the assembly of the magnet inside the transaxle is complicated, also magnetizing fixtures required to

magnetize such custom magnets are complex. Additionally, the handling of the magnet and the assembly on the shifter shaft needs to be done with utmost care. Additionally, the sensor calibration may be required at the system level which makes the vehicle level assembly process complicated.
Therefore, there exists a need to develop a magnetic position sensor, for detecting the position of the shifter shaft in the transaxle of the vehicle by overcoming the above-mentioned problems. The present disclosure is directed to overcome one or more limitations stated above or any other limitations associated with the prior art.
SUMMARY OF THE DISCLOSURE
The present disclosure provides a gear shifter shaft profile sensor for detecting a position of a shifter shaft in the transaxle of the vehicle. The profile sensor has a PCB, a magnet, a magnet holder, and a Hall integrated circuits. The PCB is configured to support one or more components of the profile sensor. The magnet is configured to face a ferrous target and the magnet holder is coupled with the PCB. The magnet holder is configured to secure the magnet. The Hall integrated circuits are placed inside the magnet, wherein the magnet is configured to at least partially cover the periphery of the Hall integrated circuits. The ferrous target comprising a step profile, which is configured to generate a distinct magnetic flux density based on the positions of the target profile radius in front of the profile sensor.
In an aspect, the step profile is a three-step profile.
In an aspect, the magnet has a C-shaped profile.
In an aspect, the profile sensor is configured to identify neutral gear, other gears, and reverse gear positions, in accordance with the radius of the step profile of the ferrous target.

In an aspect, the step profile of the unique ferrous target has three radii (Rl, R2, R3) configured to be changed by shifting the gear.
In an aspect, the step profile generates the distinct magnetic flux density corresponding to the radii of the unique ferrous target.
In an aspect, the magnet is configured to cover both the sides of the Hall integrated circuits with the magnet's south pole facing towards the target.
In an aspect, the magnet holder has a snap-lock provision to restrict the movement of the magnet in the Z-axis.
In an aspect, the magnet holder is made of a non-ferromagnetic material, preferably plastic.
The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.
BRIEF DESCRIPTION OF DRAWINGS
Further aspects and advantages of the present invention will be readily understood from the following detailed description with reference to the accompanying figure(s). The figure(s) together with a detailed description below, are incorporated in and form part of the specification, and serve to further illustrate the embodiments and explain various principles and advantages, in accordance with the present invention wherein:
Figure 1 illustrates a top view of the sensing system of the prior art 1 (EP3404368).

Figure 2 illustrates a manual gearbox equipped with a sensor of the prior art 2 (EP1882871).
Figure 3 illustrates an exploded view of a gear shifter shaft profile sensor in accordance with an embodiment of the present disclosure.
Figure 4 illustrates a perspective view of the gear shifter shaft profile sensor in accordance with an embodiment of the present disclosure.
Figure 5 illustrates a schematic view of the gear shifter shaft profile sensor in accordance with an embodiment of the present disclosure.
Figure 6 illustrates a flux generation of the gear shifter shaft profile sensor in accordance with an embodiment of the present disclosure.
Figure 7 illustrate the working of the gear shifter shaft profile sensor when the target profile radius Rl is in front of the magnetic circuit in accordance with an embodiment of the present disclosure.
Figure 8 illustrate the working of the gear shifter shaft profile sensor when the target profile radius R2 is in front of the magnetic circuit in accordance with an embodiment of the present disclosure.
Figure 9 illustrate the working of the gear shifter shaft profile sensor when the target profile radius R3 is in front of the magnetic circuit in accordance with an embodiment of the present disclosure.
Figure 10 illustrate a graphical representation of a Magnetic flux density (B) vs air gap in accordance with an embodiment of the present disclosure.

Figure 11 illustrates the location of the Hall IC in accordance with an embodiment of the present disclosure.
Figure 12 illustrates a snap-lock provided in a magnet holder in accordance with an embodiment of the present disclosure.
Skilled artisans will appreciate that elements in the drawings are illustrated for simplicity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the drawings may be exaggerated relative to other elements to help to improve understanding of embodiments of the present invention.
DETAILED DESCRIPTION OF INVENTION
While the invention is subject to various modifications and alternative forms, specific embodiment thereof has been shown by way of example in the figures and will be described below. It should be understood, however that it is not intended to limit the invention to the particular forms disclosed, but on the contrary, the invention is to cover all modifications, equivalents, and alternatives falling within the scope of the invention.
It is to alternatives that a person skilled in the art can be motivated by the present invention and can perform various modifications. However, such modifications should be construed within the scope of the invention.
Accordingly, the drawings are showing only those specific details that are pertinent to understanding the embodiments of the present disclosure so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.

The terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that an assembly, setup, system, device that comprises a list of components does not include only those components but may include other components not expressly listed or inherent to such system or device or setup. In other words, one or more elements in the system or apparatus or device proceeded by "comprises a" does not, without more constraints, preclude the existence of other elements or additional elements in the assembly or system or apparatus. The following paragraphs explain the present disclosure. The disclosure in respect of the same may be deduced accordingly.
The present disclosure relates generally to a gear shifter shaft profile sensor for detecting the position of a shifter shaft in a transaxle of the vehicle, for sensing a position of a gear shaft. Herein, the gear shifter shaft profile sensor is also referred to as a profile sensor. Further, the present invention deals with a unique ferrous target profile along with a unique magnetic circuit designed to generate distinct magnetic flux densities in presence of unique ferrous target profiles to identify neutral gear, other gear, and reverse gear positions.
According to one aspect of the disclosure, the unique magnetic circuit consists of a permanent 'C shape magnet and a hall IC placed in a magnet holder with a certain distance between them. The term "/C" is well known as integrated circuits. The complete magnet holder assembly is placed inside a sensor housing with the help of a PCB assembly. The unique ferrous target has a three-step profile, that generates distinct magnetic flux densities based on the positions of the target profile radius in front of the sensor. Thus, the sensor can identify neutral gear, other gears, and reverse gear positions.
Referring to FIGs. 3-5, the gear shifter shaft profile sensor is designed with a unique magnetic circuit along with the unique ferrous target profile (5). The ferrous target (5) may have a substantially cylindrical shape by defining an inside cavity. The ferrous target (5) may have at least one groove on the outer periphery, the at least

one groove may be configured to make a connection with the gear shifter shaft profile sensor.
The gear shifter shaft profile sensor comprises a Printed Circuit Board (PCB) (1), a magnet (2), a magnet holder (3), and a Hall IC (4). The magnet (2) is placed inside the magnet holder (3). The PCB (1) is coupled with the magnet (2). The magnet (2) defines an open cavity for accommodating the Hall IC (4). The magnet (2) produces the magnetic flux in accordance with the position of the ferrous target profile (5). The magnet (2) is configured in such a way that both the sides of the hall IC (4) are covered. In an embodiment, the magnet (2) is a C-shaped magnet.
The magnet holder (3) is configured to accommodate the magnet (2). In an embodiment, the magnet holder (3) may be made of a non-ferromagnetic material, preferably a plastic material, having sufficient strength. Further, the Hall IC (4) is positioned inside the magnet (2) with the help of a magnet holder (3) and the complete assembly is held by the PCB (1). This magnetic circuit is enclosed in the magnet holder (3) with positive locking for the magnet (2) and Hall IC (4). The magnet (2) is placed in such a way that it covers both sides of the Hall IC (4) with the magnet's south pole facing towards the target (5) as shown in FIG. 6. The periphery of the Hall IC (4) is at least partially covered by the magnet (2). Herein, the term "partially" is used to indicate that more than one side of the Hall IC (4) is covered by the magnet (2).
The unique ferrous target (5) has a three-step profile, defined by the radii Rl, R2, and R3 respectively. The three-step profile generates distinct magnetic flux densities based on the positions of the target profile radius in front of the profile sensor. Thus, the profile sensor can clearly identify neutral gear, other gears, and reverse gear positions. The target profile radius Rl, R2, and R3 may be decided based on the various magnetic simulations in such a way that enough flux densities are available to differentiate the other gear, the neutral gear, and the reverse gear as shown in FIG. 5. Herein, the target profile radius Rl is used to identify the position of other gears,

target profile radius R2 is used to identify the neutral gear position and target profile radius R3 is used to identify the reverse gear position. In another embodiment, the position of the other individual gears can also be identified by providing more profiles on the periphery of the ferrous target (5).
Moreover, the position and orientation of the target profile may be determined. When the target profile radius Rl is in front of the magnetic circuit, magnetic flux lines generated from the north pole of the magnet (2) will pass through the ferrous target and the Hall IC to form a low reluctance path as shown in FIG. 7. Further, when the target profile radius R2 is in front of the magnetic circuit, the magnetic reluctance is nominal as shown in FIG. 8. When the target profile radius R3 is in front of the magnetic circuit, the magnetic reluctance is high as shown in FIG. 9.
When the unique ferrous target (5) moves after shifting gear on Rl, R2, and R3 as shown in FIGs. 7, 8, and 9, it creates a variable reluctance path and a variable density of magnetic flux lines passing through Hall IC. This changed magnetic flux density is measured by the Hall IC to identify whether the vehicle is in the neutral gear, the other gear, or the reverse gear conditions as shown in FIG. 10. Accordingly, FIG. 10 shows a graphical representation of the magnetic flux density (B) vs the air gap (mm) between the target profile (5) and the magnetic circuit. In FIG. 10 the flux density Bl to B5 measured by Hall IC is used to identify the position of other gears i. e. corresponding to the target profile radius Rl. Similarly, the flux density B6 to BIO is used to identify the neutral gear position i. e. corresponding to the target profile radius R2. Finally, the flux densities Bl 1 to B21 are used to identify the reverse gear position i. e. corresponding to the target profile radius R3. In an embodiment, the ferrous target (5) may have more than three steps in the peripheral profile so that the position of other individual gears can be identified.
In one of the embodiments of the present disclosure, the magnetic circuit is packaged in a single housing as shown in FIGs. 11a, 1 lb, and 12. The Hall IC is located and fixed along with the X, Y, and Z-axis. As shown in FIGs. 11a and 1 lb, wherein the

'C shaped magnet is located and configured along the X and Y-axis, a snap-locks (6) are provided in the magnet holder (3) to arrest the movement of the Hall IC (4) by performing the heat stacking or hot punching operation on the snaps (6). In an embodiment, the snap-locks (6) are provided in the magnet holder (3) to restrict the movement of the magnet in Z-axis as shown in FIG. 12. The snap lock (6) works based on the deformation of a plastic wall (positive lock) while the magnet insertion into the magnet holder (3) and due to difference in dimension of the magnet (2) and the magnet holder (3), locking operation takes place. In an embodiment, another suitable locking provision may be provided to restrict the movement of the magnet (2) in Z-axis. This type of packaging of the magnetic circuit ensures the efficient functioning of the sensor under thermal and vibration conditions.
The unique magnetic circuit disclosed in the present disclosure eliminates the drawbacks of the conventional technology (i.e. the magnetic circuit and Hall IC is enclosed in different packages), hence degradation, dislocation of the magnet due to high temperature and vibration does not happen, Further, the design of the packages is robust.
It is to be understood that a person of ordinary skill in the art may develop a system of similar configuration without deviating from the scope of the present disclosure. Such modifications and variations may be made without departing from the scope of the present invention. Therefore, it is intended that the present disclosure covers such modifications and variations provided they come within the ambit of the appended claims and their equivalents.
LIST OF REFERENCE NUMERALS

Description Reference Number
PCB 1
Magnet 2

Magnet holder 3
Hall IC 4
Unique ferrous target 5
Snap-lock 6

Claim:
1. A gear shifter shaft profile sensor for detecting a position of a gear shifter
shaft in a transaxle of a vehicle, the profile sensor comprising:
a PCB (1) configured to support one or more components of the profile sensor;
a magnet (2) configured to face a ferrous target (5);
a magnet holder (3) coupled with the PCB (1), the magnet holder (3) is configured to secure the magnet (2);
a Hall integrated circuits (4) placed inside the magnet (2), wherein the magnet (2) is configured to at least partially cover the periphery of the Hall integrated circuits (4);
wherein the ferrous target (5) comprising a step profile, which is configured to generate a distinct magnetic flux density based on the positions of the target profile radius in front of the profile sensor.
2. The profile sensor as claimed in claim 1, wherein the step profile is a three-step profile.
3. The profile sensor as claimed in claim 1, wherein the magnet (2) has a C-shaped profile.
4. The profile sensor as claimed in claim 1, wherein the profile sensor is configured to identify neutral gear, other gears, and reverse gear positions, in accordance with the radius of the step profile of the ferrous target (5).
5. The profile sensor as claimed in claim 2, wherein the step profile of the unique ferrous target (5) has three radii (Rl, R2, R3) configured to be changed by shifting the gear.

6. The profile sensor as claimed in claim 5, wherein the step profile generates the distinct magnetic flux density corresponding to the radii of the unique ferrous target (5).
7. The profile sensor as claimed in claim 6, wherein the magnetic flux density decreases as an air gap between the unique ferrous target (5) and a magnetic circuit increase.
8. The profile sensor as claimed in claim 1, wherein the magnet (2) is configured to cover both the sides of the Hall integrated circuits (4) with the magnet's south pole facing towards the target (5).
9. The profile sensor as claimed in claim 1, wherein the magnet holder (3) has a snap-lock provision (6) to restrict the movement of the magnet (2) in a Z-axis.
10. The profile sensor as claimed in claim 1, wherein the magnet holder (3) is made of a non-ferromagnetic material, preferably plastic.