Set includes a tree, a magnet and a plastic piece

Abstract

The present invention relates to an assembly (10) for use in an automobile. The assembly (10) comprises a shaft (2), rotating about a longitudinal axis, and a magnet (3) disposed proximally at one end of the shaft (1). The magnet (3) has an anisotropic direction (X) perpendicular to the longitudinal axis. The magnet (3) has at least one primary flat surface (5) or one primary concave surface (5a) extending at least partially along the longitudinal axis. The assembly (10) further comprises a plastic part (2) overmolded onto the shaft (1) and the magnet (3). The at least one primary flat surface (5), or at least one tangent to the at least one primary concave surface (5a), is parallel to the anisotropic direction (X) and at least partially devoid of the plastic part (2) intended to indicate the orientation of the anisotropic direction (X). Figure from the summary: [Figure 1]

Description

Title of the invention: Assembly comprising a shaft, a magnet and a plastic part

[0001] The present invention relates to an assembly which comprises a rotating shaft, a magnet and a plastic part. The assembly is particularly intended for use in an actuator for automotive applications.

[0002] In general, actuators are used in automobiles for various applications. Such actuators may be parking lock actuators, a gear shift actuator, an electronic throttle control device, etc. These actuators are assemblies that usually include a rotating shaft, a magnet mounted on a shaft, and a rotational position sensor. Typically, the magnet is mounted on a distal end of the shaft. The magnet functions as a target for the rotational position sensor. The rotational position sensor, or sensor, is arranged in close proximity to the magnet so that the sensor detects the magnetic field generated by the magnet. As a result, information relating to the angular position of the shaft can be determined. Typically, the rotational position sensor is a Hall effect angular position sensor, or any such sensor.

[0003] In known manner, the magnet is overmolded in plastic before being mounted on the shaft. The magnet is magnetized after overmolding so that an application of high temperatures, during overmolding, does not deteriorate the anisotropic magnetic properties of the magnet. However, there is a risk that the magnet is not optimally oriented for overmolding, as a result of which the magnet may not be magnetized in a correct direction during magnetization. Therefore, the magnet, having been incorrectly magnetized, may have a shorter lifetime in terms of operation as a target in actuators.

[0004] Accordingly, it is necessary to solve the technical problem associated with the typical actuator assemblies explained above.

[0005] Therefore, an object of the present arrangement is to provide an assembly which overcomes the aforementioned and other disadvantages of known arrangements and ensures the precise orientation of the magnet in a correct direction for magnetization.

[0006] The present arrangement relates to an assembly comprising a shaft rotatable about a longitudinal axis, a magnet disposed proximally at one end of the shaft, the magnet having an anisotropic direction perpendicular to the longitudinal axis of the shaft, the magnet having at least one primary flat surface or a concave surface primary extending at least partially along the longitudinal axis, a plastic part overmolded onto the shaft and the magnet; characterized in that the at least one primary flat surface or at least one tangent to the at least one primary concave surface is parallel to the anisotropic direction of the magnet and at least partially devoid of the plastic part for indicating the orientation of the anisotropic direction. Therefore, by means of the at least one primary flat surface or the at least one primary concave surface of the magnet, the mounting position of the magnet with the mold and the plastic part is facilitated and helps to align the magnet in a magnetizer core for magnetization after overmolding with the plastic part. The at least one primary flat surface or the at least one primary concave surface of the magnet facilitates precise orientation and magnetization according to the desired anisotropic direction of the magnet.

[0007] According to one aspect of the arrangement, said magnet has at least one secondary flat surface or one secondary concave surface extending at least partially along the longitudinal axis and said at least one secondary flat surface or at least one tangent to the at least one secondary concave surface is parallel to the anisotropic direction of the magnet and at least partially overmolded with the plastic part. Therefore, thanks to the secondary flat surface or the secondary concave surface of the magnet, and the overmolding by the plastic part, the magnet can be optimally oriented by means of a tool.

[0008] According to another aspect of the arrangement, said at least one primary flat surface and the at least one secondary flat surface are opposite each other or said at least one primary concave surface and the at least one secondary concave surface are opposite each other. Therefore, upon magnetization, a magnetic field collinear to the anisotropic direction is obtained.

[0009] According to another aspect of the arrangement, the magnet has a cylindrical shape having a diameter D and extending along the longitudinal axis over a height H.

[0010] According to another aspect of the arrangement, the distance A between the at least one primary flat surface and the at least one secondary flat surface is between 0.7 times and 0.9 times the diameter D of the magnet.

[0011] According to another aspect of the arrangement, the height H of the magnet is between 0.3 times the actual diameter and the actual diameter D of the magnet.

[0012] According to another aspect of the arrangement, the width W of the at least one primary flat surface and the at least one secondary flat surface is given by width W = ^(iÿ-A2) ■

[0013] Therefore, the magnet with the cylindrical shape with flat surfaces avoids the linearity error on the signal angle of the sensor element, which measures the field axial direction of the magnet and produces a perfectly sinusoidal shape of the magnetic field.

[0014] According to another aspect of the arrangement, the magnet has a parallelepiped shape. Therefore, the magnet having the parallelepiped shape is more robust in terms of magnetic aging since it has a high permeance coefficient.

[0015] According to another aspect of the arrangement, the plastic part is a toothed element, a toothed sector or a rotor. Therefore, the plastic part which is the toothed element, the toothed sector or a rotor not only overmoldes the shaft and the magnet but also allows torque transfer between the shaft and adjacent components.

[0016] According to another aspect of the arrangement, the present invention relates to an angular position detection system comprising an assembly configured according to the present arrangement, a sensor being placed in front of the magnet. This sensor detects the magnetic field, thereby making it possible to detect the angular position of the shaft on which the magnet is fixed.

[0017] According to another arrangement, the present invention relates to an electromechanical actuator or rotating machine for use in an automotive application comprising an angular position detection system according to the present arrangement.

[0018] In yet another aspect, the present invention relates to a method of producing the present arrangement of an assembly consisting of a shaft, a magnet and a plastic part comprising the following steps:

[0019] (a) providing a ferromagnetic material having at least one flat surface primary or a primary concave surface and at least one secondary flat surface or at least one secondary concave surface extending at least partially along the longitudinal axis, said at least one primary flat surface or at least one tangent to the at least one primary concave surface of the ferromagnetic material is aligned parallel to the anisotropic direction of the ferromagnetic material;

[0020] (b) depositing the ferromagnetic material in a mold proximal to a end of the shaft with an anisotropic direction perpendicular to the longitudinal axis of the shaft by means of a tool, the tool retaining the at least one secondary flat surface or at least one secondary concave surface of the ferromagnetic magnetic material and the mold receiving at least partially the at least one primary flat surface or at least one primary concave surface of the ferromagnetic material;

[0021] (c) removing the tool and overmolding the shaft and the ferromagnetic material with the plastic part, one of the at least one secondary flat surface or at least one secondary concave surface being at least partially overmolded with the plastic part;

[0022] (d) magnetization of the ferromagnetic material by placement of the ferro material magnetic in a magnetic field. Therefore, due to the at least one primary flat surface or the at least one primary concave surface of the magnet, the mounting position of the magnet with the mold and the plastic part is facilitated and helps to align the magnet in a magnetizer core for magnetization after overmolding with the plastic part. The at least one primary flat surface or the at least one primary concave surface of the magnet facilitates precise orientation and magnetization according to the desired anisotropic direction of the ferromagnetic material.

[0023] The present arrangement may be better understood with reference to the following description and drawings. The components in the figures are not necessarily to scale, the emphasis being rather on illustrating the principles of the arrangement. In addition, in the figures, like reference numerals designate corresponding parts. In the drawings:

[0024] [Fig.l] illustrates a top view of one embodiment of an assembly configured according to the present invention;

[0025] [Fig.2] and [Fig.2a] illustrate a perspective view of a magnet assembly configured in accordance with the present invention;

[0026] [Fig.2b] and [Fig.2c] illustrate a top view of an embodiment of a magnet, according to the present invention;

[0027] [Fig.3] illustrates a perspective view of an assembly comprising a shaft and a magnet configured according to the present invention;

[0028] [Fig.4] illustrates a perspective sectional view of an assembly in which a plastic part which is a toothed sector is overmolded onto a shaft and a magnet, configured according to an arrangement of the present invention;

[0029] [Fig.5] illustrates a front view of an angular position detection system comprising an assembly configured according to the present invention;

[0030] [Fig.6] illustrates various steps of forming the magnet, configured according to an embodiment of the present invention; and;

[0031] [Fig.7] is a flowchart showing a magnet assembly process configured in accordance with an arrangement of the present invention.

[0032] The figures are not necessarily to scale and the size of certain parts may be exaggerated to more clearly illustrate the example shown. In addition, the drawings provide examples and / or examples in accordance with the description; however, the description is not limited to the examples and / or examples provided in the drawings.

[0033] In the following description, reference is made to accompanying drawings, which form a part thereof, and in which there are shown illustratively specific embodiments in which the invention may be applied. These embodiments are described in sufficient detail to enable a person of the art to practice the invention, and it will be understood that the embodiments may be combined or other embodiments may be used and that structural and logical modifications may be made without departing from the scope of the present invention. The following detailed description should therefore not be construed as limiting and the scope of the present invention is defined by the appended claims and their equivalents.

[0034] [Fig.l] illustrates a top view of an assembly 10, configured according to the present invention, which comprises a shaft 1, a magnet 3, a mold and a plastic part 2. The shaft 1 is configured to rotate about a longitudinal axis. The magnet 3 is arranged proximally at one end of the shaft 1 with an anisotropic direction X perpendicular to the longitudinal axis of the shaft 1. The magnet 3 has at least one primary flat surface 5 extending at least partially along the longitudinal axis. The plastic part 2 is overmolded onto the shaft 1 and partially overmolded onto the magnet 3, thereby holding the magnet 3 in place on the shaft 1. The at least one primary flat surface 5 is parallel to the anisotropic direction X of the magnet 3 and at least partially free of the plastic part 2.Thus, the at least one primary flat surface 5 which is devoid of the plastic part 2 indicates the anisotropic direction X of the magnet 3 and facilitates the precise orientation and magnetization of the magnet 3 according to its anisotropic direction X.

[0035] According to one aspect of the present invention, the magnet 3 comprises at least one secondary flat surface 6 which extends at least partially along the longitudinal axis 4. The at least one secondary flat surface 6 is parallel to the anisotropic direction X of the magnet 3 and is at least partially overmolded in the plastic part 2. Furthermore, the mold comprises structures 20a, 20b, 20c similar to fingers which facilitate the reception of the magnet 3 and the holding of said magnet 3 in place.

[0036] In the example shown in [Fig.l], the magnet 3 is formed with a cylindrical shape 7 and extends at least partially along the longitudinal axis. The magnet 3 in [Fig.l] has a primary flat surface 5 and a secondary flat surface 6, both of which are opposite each other. The mold receives the magnet 3 by means of three finger-like structures 20a, 20b, 20c, spaced 120° apart from each other. One of the finger-like structures 20a of the mold is a flat surface 17 which at least partially abuts the primary flat surface 5, thereby limiting the relative rotation of the magnet 3 before or during the overmolding process. The other two structures 20b; 20c similar to mold fingers have a curved surface (due to the cylindrical shape 18, 19) abutting against the cylindrical shape 7 which completes the curved area of ​​the mold. As a result, the magnet 3 is held and indexed in the mold.

[0037] According to another embodiment of the present invention, the magnet 3 comprises at least one primary concave surface and one secondary concave surface extending at least partially along the longitudinal axis of the shaft 1.

[0038] According to the example shown in [Fig. 1], the plastic part 2 partially covers the shaft 1 and partially covers the magnet 3. The plastic part 2 holds the magnet 3 in such a way that the secondary flat surface 6 is at least partially overmolded with the plastic part 2. Said plastic part 2 has a flat surface 14 which at least partially abuts against the secondary flat surface 6, limiting the relative rotation of the magnet 3 in the plastic part 2 during operation of the assembly 10. Thanks to the primary flat surface 5, which is free of the plastic part 2, the orientation direction (magnetization direction) can be identified immediately. The plastic part 2 further has two finger-like structures with a curved surface (due to the cylindrical shape 15, 16) abutting against the cylindrical shape 7 which completes the cylindrical shape 7 of the magnet 3.As a result, the mounting position of the magnet 3 is maintained and indexed in the plastic part 2.

[0039] Figure 2 illustrates a perspective view of a magnet 3 configured according to the present invention. Figure 2a illustrates a perspective view of a magnet 3 configured according to the present invention. Figure 2b illustrates a top view of the magnet 3 configured according to one embodiment of the present invention. For the sake of brevity, the description of Figure 2, Figure 2a and Figure 2b is described herein in tandem. The magnet 3 is formed with the cylindrical shape 7 and has the longitudinal axis 4 perpendicular to the anisotropic direction X. Preferably, the diameter D of the cylindrical shape 7 is between 4 mm and 14 mm. It is also preferable that the height H of the magnet 3 is between 0.3 times the actual diameter and the actual diameter D of the magnet 3, the height H being along the longitudinal axis 4.As explained in the preceding description, the primary flat surface 5 and the secondary flat surface 6 are formed such that said surfaces 5 and 6 are both parallel to the anisotropic direction X of the magnet 3 and opposite to each other. In the example shown, the distance A between the primary flat surface 5 and the secondary flat surface 6 is configured to be anywhere between 0.7 times and 0.9 times the diameter D of the magnet 3. The width W of the primary flat surface 5 and the width W of the secondary flat surface 6 are given by the width W = ^d2_ A2} • .

[0040] The magnet 3 is diametrically magnetized. In an exemplary embodiment, the magnet 3 may be a rare earth magnet, such as neodymium iron boron (sintered) with a nickel coating or optionally anisotropic hard ferrite. Preferably, the tolerance of the flat surface of the at least one surface primary plate 5 and the at least one secondary flat surface 6 is between 10 and 15% of the height H of the magnet 3. Furthermore, the magnet 3 with the cylindrical shape 7 avoids the linearity error on the signal angle of the sensor element, which measures the axial field of the magnet 3 and produces a perfectly sinusoidal shape of the magnetic field.

[0041] In an exemplary embodiment, the magnet 3 is formed with a parallelepiped shape having a primary flat surface and a secondary flat surface which are parallel to the anisotropic direction X of the magnet 3 and are opposite to each other. Preferably, the distance between the primary flat surface and the secondary flat surface is between 5 mm and 5.6 mm.

[0042] In an exemplary embodiment as illustrated in [Fig.2c], the magnet 3 has a cylindrical shape 7 which extends along the longitudinal axis 4 and has a primary concave surface 5a and a secondary concave surface 6a. At least one tangent to said one primary concave surface 5a is parallel to the anisotropic direction X of the magnet 3. A tangent to said one secondary concave surface 6a is parallel to the anisotropic direction X of the magnet 3.

[0043] In yet another embodiment, the plastic part 2 is overmolded onto the shaft 1 and partially overmolded onto the magnet 3, thereby holding the magnet 3 in place on the shaft 1. The at least one tangent to the primary concave surface 5a is parallel to the anisotropic direction X of the magnet 3 and at least partially free of the plastic part 2. Thus, the primary concave surface 5a which is free of the plastic part 2 indicates the anisotropic direction X of the magnet 3 and facilitates the precise orientation and magnetization of the magnet 3 along its anisotropic direction X. Furthermore, according to the present invention, the magnet 3 has a secondary concave surface 6a which extends at least partially along the longitudinal axis 4. The at least one tangent to the secondary concave surface 6a is parallel to the direction anisotropic X of the magnet 3 and is at least partially overmolded in the plastic part 2.Therefore, the primary concave surface 5a that abuts the mold helps to limit the relative movement of the magnet 3 in the mold before or during the overmolding process. Similarly, the secondary concave surface 6a that abuts the plastic part 2 helps to limit the relative movement of the magnet 3 in the plastic part 2 during operation of the assembly 10.

[0044] In another embodiment, the magnet 3 is formed with a parallelepiped shape having a primary concave surface and a secondary concave surface. At least one tangent to said primary concave surface is parallel to the anisotropic direction X of the magnet 3. At least one tangent to said secondary concave surface is parallel to the anisotropic direction X of the magnet 3.

[0045] In yet another embodiment, the primary and secondary surfaces may have a profile non-conformity with the flat surface. The profile may be a cross-sectional profile as seen in a top view. For example, without limitation, said profile non-conformity with the flat surface of the magnet 3 has raised and lowered portions. Without limitation, the profile of the raised and lowered portions may resemble a stair-step or saw-tooth pattern.

[0046] [Fig. 3] illustrates a perspective view of an assembly 10 which comprises a shaft 1 and a magnet 3, the assembly 10 being configured according to the present invention. The plastic part 2 as shown in [Fig. 1] is not shown here. The shaft 1 is circular in cross-section and extends along the longitudinal axis 4 and used to transmit power, torque or rotary motion between two parts of a machine or from a torque-producing machine to a torque-absorbing machine. The magnet 3 is disposed proximally at one end of the shaft 1 with an anisotropic direction X perpendicular to the longitudinal axis 4 of the shaft 1. The outer periphery of the shaft 1 has at least one groove 1a which facilitates the retention of the plastic part 2 which is overmolded.

[0047] [Fig. 4] illustrates a perspective sectional view of an assembly 10 configured according to an example of the present invention. As shown in [Fig. 4], the plastic part 2 is a toothed sector 2a and is partially overmolded onto the shaft 1 and the magnet 3. The toothed sector 2a is a segment of a toothed element that extends in an angular range anywhere between 0° and 360°, preferably between 0° and 90° while the toothed element may extend over the entire 360°. The toothed sector 2a is similar to a toothed element while the toothed sector 2a has teeth 2b for a limited segment on its outer periphery and a smooth retaining portion. In another arrangement, the toothed sector 2a may have more than one limited section for example two opposing segments on its outer periphery.The toothed sector 2a rotates around said longitudinal axis 4 around which the shaft 1 rotates and is usually present in actuators where a limited repeated rotation around the longitudinal axis 4 is required. The shaft 1, the plastic part 2 and the magnet 3 are arranged coaxially around the longitudinal axis 4. The magnet 3 has the primary flat surface 5 and the secondary flat surface 6 and said primary flat surface 5 and the secondary flat surface 6 are parallel to the anisotropic direction X of the magnet 3 and are opposite to each other. The secondary flat surface 6 is overmolded with the plastic part 2 while the primary flat surface 5 is devoid of the plastic part 2 and is visible. As a result of which the orientation direction (magnetization direction) can be identified immediately for the magnetization of the magnet 3.

[0048] In one example, the plastic part 2 may preferably be a toothed element. In yet another example, the plastic part 2 may preferably be a rotor, but not limited to, the rotor may be a plastic rotor comprising magnetic particles or magnets. Said toothed element or the rotor is overmolded onto the shaft 1 and the magnet 3 configured according to the present invention.

[0049] In yet another embodiment, the magnet 3 is indirectly coupled to the shaft 1. More specifically, in the aforementioned embodiment, a metal insert is arranged between the shaft 1 and the magnet 3, to facilitate the aforementioned coupling. The plastic part 2 is at least partially overmolded onto the magnet 3 and at least partially overmolded onto the metal insert.

[0050] [Fig. 5] illustrates a front view of an angular position detection system 21 configured according to the present invention. The angular position detection system 21 comprises the assembly 10 configured according to the present invention. The assembly 10 comprises the shaft 1, the magnet 3, the sensor 22 and the plastic part 2. The magnet 3 has at least one primary flat surface 5 or one primary concave surface 5a extending at least partially along the longitudinal axis 4. The plastic part 2 overmolded on the shaft 1 and the magnet 3 is characterized in that the at least one primary flat surface 5 or at least one tangent to the at least one primary concave surface 5a is parallel to the anisotropic direction X of the magnet 3 and at least partially devoid of the plastic part 2 intended to indicate the orientation of the anisotropic direction X. In one example, the sensor 22 is, for example, a Hall effect sensor or a magnetoresistive sensor (MR sensor).Both sensors detect a generated magnetic field while the Hall sensor detects the polarity of the magnetic field and the MR sensor detects the angular position of the magnetic field. The two types of sensors are often used together because their modes of operation are complementary to each other.

[0051] [Fig. 6] illustrates a process for implementing an embodiment of a magnet 3 configured according to the present invention. In the example illustrated in [Fig. 6], the magnet 3 is manufactured by a material removal process such as milling, shaping. Preferably, the raw material used is the ferromagnetic material 23 in the form of a rectangular bar having a width 24 and a length 25, 26. The width 24 of the ferromagnetic material 23 is transformed into a cylindrical shape 7. Then the length 25, 26 of the ferromagnetic material 23 is subjected to surface machining to form the at least one primary flat surface 5 and the at least one secondary flat surface 6.

[0052] [Fig. 7] is a flowchart illustrating steps of manufacturing a magnet and an assembly process, configured according to the present invention. In step 71, the raw material which is the ferromagnetic material 23 is provided. In one example, the magnet 3 is manufactured by a process of removing material from the material ferromagnetic material 23, in a non-limiting manner as described above. Thus, as in step 72, the manufactured magnet 3 has at least one primary flat surface 5 or one primary concave surface 5a and at least one secondary flat surface 6 or one secondary concave surface 6a extending at least partially along the longitudinal axis 4 and said at least one primary flat surface 5 or at least one tangent to the at least one primary concave surface 5a of the ferromagnetic material 23 is aligned parallel to the anisotropic direction X of the ferromagnetic material 23.

[0053] Further, as in step 73, the deposition of the ferromagnetic material 23 in a mold is carried out.The ferromagnetic material 23 is deposited in a mold proximally at one end of the shaft 1 with an anisotropic direction X perpendicular to the longitudinal axis 4 of the shaft 1 by means of a tool, the tool retaining the at least one secondary flat surface 6 or at least one secondary concave surface 6a of the ferromagnetic magnetic material 23 and the mold receiving at least partially the at least one primary flat surface 5 or at least one primary concave surface 5a of the ferromagnetic material 23. To provide an example in a non-limiting manner, the mold may have at least one finger-like structure. Said finger-like structure of the mold is a flat surface 17 which receives at least partially the at least one primary flat surface 5 of the magnet 3 and is intended to limit the relative rotation of the ferromagnetic material 23.In another example, said finger-like structure of the mold has a convex surface that at least partially receives the at least one primary concave surface 5a of the ferromagnetic material 23 and is intended to limit the relative rotation of the ferromagnetic material 23. As a result, the ferromagnetic material 23 is held and indexed in the mold.

[0054] Further, as in step 74, the tool removal operation is performed and the overmolding of the shaft 1 and the ferromagnetic material 23 with the plastic part 2 is performed, at least one secondary flat surface 6 or at least one secondary concave surface 6a being at least partially overmolded with the plastic part 2.To provide an example in a non-limiting manner, the plastic part 2 is at least partially overmolded onto the ferromagnetic material in such a way that the plastic part 2 retains the at least one secondary flat surface 6 or the at least one secondary concave surface 6a of the ferromagnetic material 23 intended to limit the relative rotation of the magnet 3 and from the at least one primary flat surface 5 or at least one primary concave surface 5a of the ferromagnetic material 23 which is at least partially devoid of the plastic part 2, the orientation direction (magnetization direction) can be identified immediately. As a result, the mounting position of the magnet 3 is maintained and indexed in the plastic part 2.

[0055] Further, as in step 75, the magnetization of the ferromagnetic material is performed by placing the shaft 1 and the ferromagnetic material 23, which is overmolded with the plastic part 2, in a magnetic field. The ferromagnetic magnetic material 23, overmolded with the plastic part 2, is positioned and clamped in a tool and then a coil is approached. In one example, the coil may be a magnetizer core or a C-shaped coil. An electric current is caused to flow through the coil, which creates a strong magnetic field. The ferromagnetic material 23 is placed in the coil in such a way that the anisotropic direction X of the ferromagnetic material 23 is aligned with the magnetic field generated by the magnetizer. The electric current flowing through the coil must be high enough to saturate the magnetization of the ferromagnetic material 23. Thus, the ferromagnetic material 23 becomes magnetized.

[0056] The assembly 10 comprising a shaft 1, a magnet 3 and a plastic part 2 according to the present invention, as described above, is particularly advantageous in applications in which automotive components such as an electromechanical actuator or a rotating machine or a pump are assembled in a motor vehicle. In one example, the present arrangement particularly provides an automotive rotating machine which comprises an angular position detection system 12 configured according to the present invention. The rotating machine may be an electrodynamic machine, preferably an electric generator or an electromechanical drive machine (i.e. an electric motor) or an electric oil pump.In this case, all known examples, such as those of a synchronous machine, an asynchronous machine, a direct current machine or a brushless direct current motor (BLDC motor) having a rotor consisting of a magnetic pole or a reluctance machine, are conceivable. Furthermore, the field of application is not limited to electrical machines. In another aspect, the rotating machine may also be an internal combustion engine having a shaft whose rotational position is to be detected.

[0057] In another example, the corresponding electromechanical actuator is a gearbox actuator, also known as a gearshift actuator, used in particular for selecting and switching a transmission between gear ranges in an automotive transmission. To perform the aforementioned operation, the gearbox actuator comprises a shaft 1 and a magnet 3 in the output mechanism, configured according to the present invention. Said shaft 1 and the magnet 3 are overmolded with a plastic part 2, for example the plastic part 2 being a toothed sector 2a rotatable about the longitudinal axis 4. The magnet 3 has an anisotropic direction X perpendicular to the longitudinal axis 4 of the shaft 1. The magnet 3 has at least one primary flat surface 5 or a primary concave surface 5a extending at least partially along the axis Ion- gitudinal 4 and said at least one primary flat surface 5 or at least one tangent to the at least one primary concave surface 5a is parallel to the anisotropic direction X of the magnet 3 and at least partially devoid of the plastic part 2 intended to indicate the orientation of the anisotropic direction X. The output mechanism further comprises a gearshift finger or the like coupled to said shaft 1. The aforementioned gearbox actuator further comprises a drive motor, a control device electrically connected to the drive motor and configured to control the drive motor, and a reduction mechanism. Said output mechanism is coupled to the drive motor using the reduction mechanism. Said control device comprises at least one magnetic field sensor configured to detect an angular position of the shaft 1 in which the toothed sector 2a is overmolded.

[0058] In another example, the corresponding electromechanical actuator may be for example a parking lock actuator or a transmission lock actuator according to the present arrangement used in particular for controlling the parking pawl in an automotive application. Said parking pawl is able to move between a first position in which the parking pawl prevents rotation of the output shaft and a second position in which the parking pawl does not prevent rotation of the output shaft. To perform the aforementioned operation, the parking lock actuator of the transmission lock actuator comprises a shaft 1 and a magnet 3 in the output mechanism, configured according to the present invention. Said shaft 1 and the magnet 3 are overmolded with a plastic part 2 for example the plastic part 2 being a toothed sector 2a rotatable about the longitudinal axis 4.The magnet 3 has an anisotropic direction X perpendicular to the longitudinal axis 4 of the shaft 1. The magnet 3 has at least one primary flat surface 5 or one primary concave surface 5a extending at least partially along the longitudinal axis 4 and said at least one primary flat surface 5 or at least one tangent to the at least one primary concave surface 5a is parallel to the anisotropic direction X of the magnet 3 and at least partially devoid of the plastic part 2 intended to indicate the orientation of the anisotropic direction X. The aforementioned parking lock actuator or transmission lock actuator further comprises a drive motor, a control device electrically connected to the drive motor and configured to control the drive motor, comprising at least one magnetic field sensor configured to detect an angular position of the shaft 1 in which the toothed sector 2a is overmolded, and a reduction mechanism.

[0059] In yet another example, the corresponding electromechanical actuator may be, for example, an electronic throttle control device according to the present arrangement used in particular as a fluid metering valve of internal combustion engines, in such cases gasoline or diesel engines are possible. It can also be used as an exhaust gas recirculation valve or EGR valve. Said electronic throttle control device comprises a fluid metering valve, for example is a throttle valve, a shutter or a flap, which operates between first and second positions, a control shaft unit which is connected to said fluid metering valve, a drive unit and a gear mechanism coupled to the drive unit. The drive unit is configured to rotate the valve between the first and second positions. Rotation of the valve allows regulating the flow of fluid flowing in a line. To perform the aforementioned operation, said control shaft unit is configured according to the present invention.Said control shaft unit comprises a shaft 1 and the magnet 3 and is overmolded with a plastic part 2 for example the plastic part 2 being a toothed sector 2a rotatable about the longitudinal axis 4. The magnet 3 has an anisotropic direction X perpendicular to the longitudinal axis 4 of the shaft 1. The magnet 3 has at least one primary flat surface 5 or a primary concave surface 5a extending at least partially along the longitudinal axis 4 and said at least one primary flat surface 5 or at least one tangent to the at least one primary concave surface 5a is parallel to the anisotropic direction X of the magnet 3 and at least partially devoid of the plastic part 2 intended to indicate the orientation of the anisotropic direction X. The electronic throttle control device further comprises at least one magnetic field sensor adapted to detect an angular position of the shaft 1 in which the sector toothed 2a is overmolded.Other applications of the valve according to the invention are also possible without departing from the scope of the invention.

[0060] However, it will be understood that the application is not limited to a gear shift actuator or a parking lock actuator or an electronic throttle control device only, the present invention can be applied to various other automotive components, which include an assembly 10 having a shaft 1, a magnet 3 and a plastic part 2.

Claims

Claims

1. An assembly (10) comprising a shaft (1) rotatable about a longitudinal axis (4), a magnet (3) arranged proximally at one end of the shaft (1), the magnet (3) having an anisotropic direction (X) perpendicular to the longitudinal axis (4) of the shaft (1), the magnet (3) having at least one primary flat surface (5) or one primary concave surface (5a) extending at least partially along the longitudinal axis (4), a plastic part (2) overmolded onto the shaft (1) and the magnet (3), characterized in that the at least one primary flat surface (5) or at least one tangent to the at least one primary concave surface (5a) is parallel to the anisotropic direction (X) of the magnet (3) and at least partially devoid of the plastic part (2) intended to indicate the orientation of the anisotropic direction (X).

2. Assembly (10) according to claim 1, characterized in that said magnet (3) has at least one secondary flat surface (6) or one secondary concave surface (6a) extending at least partially along the longitudinal axis (4) and said at least one secondary flat surface (6) or at least one tangent to the at least one secondary surface (6a) is parallel to the anisotropic direction (X) of the magnet (3) and at least partially overmolded with the plastic part (2).

3. Assembly (10) according to claim 2, characterized in that said at least one primary flat surface (5) and the at least one secondary flat surface (6) are opposite each other or said at least one primary concave surface (6) and the at least one secondary concave surface (6a) are opposite each other.

4. Assembly (10) according to any one of the preceding claims, characterized in that the magnet (3) has a cylindrical shape (7) having a diameter D and extending along the longitudinal axis (4) over a height H.

5. Assembly (10) according to claim 4, characterized in that the distance A between the at least one primary flat surface (5) and the at least one secondary flat surface (6) is between 0.7 times and 0.9 times the diameter D of the magnet (3).

6. Assembly (10) according to claim 4 or 5, characterized in that the height H of the magnet (3) is between 0.3 times the actual diameter and the actual diameter D of the magnet (3).

7. Assembly (10) according to claim 4 or 5, characterized in that the

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10.

11.

12. width W of the at least one primary flat surface (5) and of the at least one secondary flat surface (6) is given by width W = ^(d2-a2) Assembly (10) according to any one of claims 1 to 3, characterized in that the magnet (3) has a parallelepiped shape. Assembly (10) according to any one of the preceding claims, characterized in that the plastic part (2) is a toothed element, a toothed sector (2a) or a rotor. An angular position sensing system (21) comprising an assembly (10) configured according to any preceding claim and a sensor (22) positioned in front of the magnet (3). An electromechanical actuator or rotating machine for use in an automotive application comprising an angular position sensing system (21) according to claim 10. A method of producing an assembly (10) consisting of a shaft (1), a magnet (3) and a plastic part (2) comprising the following steps: a. providing a ferromagnetic material (23) having at least one primary flat surface (5) or one primary concave surface (5a) and at least one secondary flat surface (6) or at least one secondary concave surface (6a) extending at least partially along the longitudinal axis (4) and said at least one primary flat surface (5) or at least one tangent to the at least one primary concave surface (5a) of the ferromagnetic material (23) is aligned parallel to the anisotropic direction (X) of the ferromagnetic material (23); b. depositing the ferromagnetic material (23) in a mold (20) proximally to one end of the shaft (1) with an anisotropic direction (X) perpendicular to the longitudinal axis (4) of the shaft (1) by means of a tool, the tool retaining the at least one secondary flat surface (6) or at least one secondary concave surface (6a) of the ferromagnetic magnetic material (23) and the mold (20) receiving at least partially the at least one primary flat surface (5) or at least one primary concave surface (5a) of the ferromagnetic material (23); c. removal of the tool and overmolding of the shaft (1) and the material ferromagnetic (23) with the plastic part (2), one of the at least one secondary flat surface (6) or at least one secondary concave surface (6a) being at least partially overmolded with the plastic part (2); d. magnetizing the ferromagnetic material (23) by placing the ferromagnetic material (23) in a magnetic field.

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