Magnetic field sensor comprising a ring magnet and a support sleeve and corresponding method

Abstract

Magnetic field sensor comprising a ring magnet and a support sleeve and corresponding method. This magnetic field sensor comprises a sensor head, the sensor head having a printed circuit board end portion 18 of a printed circuit board 12, as well as a Hall element 22 and a ring magnet 16. The Hall element 22 is arranged on a printed circuit board surface 20. A support sleeve 14 partially engages around the printed circuit board end portion 18 comprising the Hall element 22. The support sleeve has a support sleeve recess 26, which extends beyond an outer contour of the Hall element 22 in a plane perpendicular to the printed circuit board 12 and is open at one end of the support sleeve 30 of the support sleeve 14.The ring magnet 16 is arranged on the support sleeve 14 such that the Hall element 22 is arranged at least partially inside the ring magnet 16. Figure for the abbreviation: Figure 2.

Description

Title of the invention: Magnetic field sensor comprising a ring magnet and a support sleeve and corresponding method

[0001] The invention relates to a magnetic field sensor comprising a sensor head, the sensor head having a printed circuit board terminal portion and, at the printed circuit board terminal portion, a Hall effect sensor and a ring magnet. The invention further relates to a method for manufacturing a magnetic field sensor.

[0002] A magnetic field sensor of the aforementioned type is known, for example, as a speed sensor for a speed recorder in a motor vehicle, particularly in a commercial vehicle. The magnetic field sensor is screwed into a transmission housing in the vehicle's drivetrain and detects the movement of a gear in the transmission using its sensor head. For accurate operation of the magnetic field sensor, precise positioning of the sensor head, in particular the Hall effect element and the ring magnet of the sensor head, relative to the transmission gear is required. To ensure this, a very precise arrangement of the Hall effect element and the ring magnet in the sensor head is necessary during the manufacturing of the magnetic field sensor.

[0003] The objective of the invention is to provide a magnetic field sensor of the type The aforementioned device can be manufactured in a simplified manner and offers high measurement accuracy. The objective of the invention is further to provide a manufacturing method for a magnetic field sensor that allows for simplified fabrication of a magnetic field sensor exhibiting high measurement accuracy.

[0004] The first objective is achieved according to the invention using a magnetic field sensor of the aforementioned type, the Hall element being arranged on a printed circuit board surface of the printed circuit board end portion and a support sleeve being arranged on the printed circuit board so as to engage at least partially around the printed circuit board end portion comprising the Hall element, the support sleeve having a support sleeve recess at least in one direction extending away from one end of the printed circuit board of the printed circuit board end portion parallel to the printed circuit board, which support sleeve recess extends at least one outer contour of the Hall element in a plane perpendicular to the printed circuit board and is open at one end of the support sleeve of the support sleeve which is opposite the end of the printed circuit board of the terminal portion of the printed circuit board presenting the Hall element, and the ring magnet being arranged on the support sleeve such that the Hall element is arranged at least partially inside the ring magnet.

[0005] Thanks to the invention, it is advantageously possible, particularly in the case of high-volume production, to manufacture the magnetic field sensor very precisely and with very high process reliability due to the special arrangement according to the invention of the printed circuit board, the Hall effect sensor, the support sleeve, and the ring magnet. It is important that the Hall effect sensor be arranged on a surface of the printed circuit board, so that, in particular, a complex arrangement of the Hall effect sensor on a front surface of the printed circuit board's end section is avoided. The support sleeve is preferably cylindrical and can, in particular, be called a cylindrical sleeve, for example.The arrangement of the support sleeve on the printed circuit board can, for example, be a clamping arrangement, so the support sleeve can, for example, be designated as a clamping sleeve, which is clamped onto the printed circuit board.

[0006] According to the invention, it is particularly advantageous, for example, that a special clamping element is not required and can be saved. Consequently, during the manufacture of the magnetic field sensor, an additional bonding step, otherwise necessary for bonding such a clamping element, is further eliminated. Advantageously, again according to the invention, for example, no additional positioning sleeve is required, which would otherwise have to be provided, for example, for complete and reliable injection of the sensor head. Furthermore, the invention advantageously allows the manufacture of magnetic field sensors of different lengths without the need for a different tooling for manufacturing these sensors of different lengths.

[0007] The printed circuit board is preferably an elongated printed circuit board, that is, a printed circuit board with a longitudinal extension. The magnetic field sensor is, in particular, a bar-shaped magnetic field sensor. A longitudinal axis of the magnetic field sensor and a longitudinal axis of the printed circuit board preferably coincide.

[0008] The Hall element can, for example, be a surface-mountable component. Therefore, simultaneous mounting and welding of the Hall element are possible. The Hall effect in conjunction with other electronic components on the printed circuit board is made possible. For example, the Hall effect element can be a Hall effect integrated circuit. In a particular embodiment, the Hall effect element can also be a Hall effect integrated circuit. The ring magnet can preferably be a permanent magnet. In a particular embodiment, the ring magnet can also be a permanent magnet.

[0009] The recess in the support sleeve is arranged parallel to the printed circuit board and, therefore, in particular, parallel to the longitudinal axis of the printed circuit board. Furthermore, the recess in the support sleeve extends beyond an outer contour of the Hall effect sensor in a plane perpendicular to the printed circuit board and, therefore, in particular, perpendicular to the longitudinal axis of the printed circuit board and, in particular, to the dimension, especially the height, of the Hall effect sensor, which is arranged on the printed circuit board. The recess in the support sleeve thus forms a tunnel within the support sleeve, which tunnel, at least with respect to its outer dimensions that form an inner contour of the support sleeve, is suitable for housing the Hall effect sensor. Such a tunnel, which forms the recess in the support sleeve, is preferably a through tunnel through the support sleeve.Due to the special arrangement of the tunnel, it is possible to first position the Hall element on the printed circuit board surface of the printed circuit board end section and then place, in particular thread, the support sleeve onto the printed circuit board end section, without damaging the Hall element, in particular without there being a risk of shearing the Hall element in such a way as to detach it from the printed circuit board by means of the support sleeve during the placement or threading of the support sleeve onto the printed circuit board end section.

[0010] Furthermore, the support sleeve holds the ring magnet, which only needs to be mounted on the support sleeve once the latter is mounted on the printed circuit board. Preferably, the ring magnet can be threaded onto the support sleeve. Because the Hall effect sensor is at least partially located inside the ring magnet, the best possible measurement signal can be generated by the magnetic field sensor.

[0011] The invention has another advantage in that the bonding surfaces of a bonded assembly of the support sleeve and the printed circuit board can be relatively large, and consequently the stability of an arrangement consisting of the support sleeve, the ring magnet, the Hall element, and the printed circuit board is further increased. Moreover, according to the invention, such a bonded assembly allows for attachment in the immediate vicinity and in the longitudinal direction of The ring magnet is positioned so that no rotational stress is produced on the bonded assembly. Mechanical stresses can advantageously be absorbed directly in the region of the ring magnet.

[0012] Also with regard to a bonded assembly of the ring magnet and the support sleeve, the invention advantageously allows for a relatively large bonding surface. As a bonding surface, an inner wall region (or inner contour) and a front surface of the ring magnet, as well as an outer wall region of the support sleeve (or sleeve contour) corresponding to the inner wall region and an axial stop of the support sleeve, corresponding to the front surface of the support sleeve, can advantageously be used. Thus, a holding force can generally be increased.

[0013] Preferably, the support sleeve for the magnetic field sensor according to the invention does not have external spacer fingers, i.e., fingers protruding radially from the support sleeve. The support sleeve can dispense with such spacer fingers, which might otherwise be necessary to allow, for example, the flow of the sealing compound, since the sealing compound can reach the Hall effect sensor and the printed circuit board end through the tunnel formed by the recess in the support sleeve, and possibly also through overflow channels on an outer periphery of the support sleeve, unobstructed and completely into the sensor head. This allows for reliable complete filling of the sensor head with sealing compound while simultaneously expelling any air bubbles that may have formed within the sensor head.Advantageously, this method achieves high ESD resistance, i.e., high protection against electrostatic discharge (ESD). Simultaneously, the wall thickness of the magnetic field sensor housing, particularly the sensor head, can advantageously be relatively large, especially in the area of ​​a thread relief groove and / or in the immediate vicinity of the thread end of the sensor head's external thread. These areas are frequently subjected to particularly high mechanical stress for predefined dimensions of the sensor head's external thread. Thus, the stability of the sensor housing can be increased, and / or a housing material that reduces manufacturing costs for the magnetic field sensor can be used.

[0014] The magnetic field sensor according to the invention is particularly suitable for use as a speed detector for a vehicle speed recorder, especially for a commercial vehicle, for example, a heavy goods vehicle. Such a speed recorder may also be called a tachograph. The sensor of The magnetic field is connected to the tachograph and is used to provide it with a movement signal, in particular a vehicle speed signal.

[0015] Further advantageous improvements of the invention are indicated below.

[0016] According to an advantageous improvement of the invention, the support sleeve recess is a through-recess in the support sleeve and forms an inner contour of the support sleeve. This inner contour has two opposing longitudinal grooves that receive the printed circuit board. Consequently, assembly of the support sleeve and the printed circuit board is easily facilitated. In particular, a rotationally locked arrangement of the support sleeve on the printed circuit board can thus be achieved. Preferably, the support sleeve recess is a central through-recess in the support sleeve.The longitudinal grooves extend in particular parallel to the longitudinal extent of the printed circuit board, that is to say parallel to the longitudinal axis of the printed circuit board, so that they receive the printed circuit board between them parallel to its longitudinal extent.

[0017] For the purpose of precise alignment of the support sleeve and the printed circuit board, it is particularly advantageous that, according to an improvement of the invention, at least one of the longitudinal grooves has at least one lug or longitudinal rib. Such a lug may, for example, also be called a raised bump. The lug or longitudinal rib is preferably located at the bottom of a groove corresponding to a longitudinal edge of the printed circuit board. A further improvement provides that both longitudinal grooves have at least one corresponding lug or longitudinal rib.

[0018] According to another advantageous improvement of the invention, the printed circuit board has an axial stop, and the support sleeve bears against this axial stop. The axial stop can, for example, be formed by a shoulder on the printed circuit board that protrudes radially from the longitudinal axis of the printed circuit board. Thanks to the improvement described here, precise and accurate positioning of the support sleeve on the printed circuit board in the axial direction, i.e., in the direction of the longitudinal axis of the sensor, can be achieved in a particularly simple manner.The support sleeve, during the manufacture of the magnetic field sensor, can be precisely threaded up to the axial stop of the printed circuit board on the printed circuit board, particularly on the end portion of the printed circuit board.

[0019] For the purpose of precise positioning of the ring magnet on the support sleeve, it is particularly advantageous that, according to another advantageous improvement of the invention, the support sleeve has an axial stop at one end of the support sleeve opposite the printed circuit board end. The axial stop preferably serves as a stop for the ring magnet, so that the ring magnet bears against the axial stop in the assembled state of the support sleeve and the ring magnet. Preferably, the axial stop is annular at the end of the support sleeve that is opposite the printed circuit board end.

[0020] According to an advantageous improvement of the invention, the axial stop of the support sleeve is annular and has at least one overflow channel on its outer periphery. During the manufacture of the magnetic field sensor, this advantageously provides a means for a sealing compound to flow easily in front of the support sleeve to the printed circuit board end and completely into the sensor head, and / or for the air contained in the sensor head to escape into the region of the printed circuit board end during the manufacture of the magnetic field sensor. The annular design of the axial stop of the support sleeve means, in other words, that the axial stop of the support sleeve is formed peripherally around the support sleeve.At least one overflow channel can, for example, be implemented as a longitudinal groove on the outer periphery of the axial stop of the support sleeve. Preferably, a plurality of overflow channels are provided on the outer periphery of the axial stop of the support sleeve. The at least one overflow channel, or overflow channels, is, or are, in particular, oriented parallel to the longitudinal axis of the printed circuit board and therefore also parallel to the longitudinal axis of the sensor.

[0021] According to another advantageous improvement of the invention, the axial stop of the support sleeve has at least one bearing surface projecting axially towards the end of the printed circuit board. Thus, the adjustment accuracy of the arrangement of the ring magnet and the support sleeve can be further increased in a simple manner. The axial projection of the at least one bearing surface towards the end of the printed circuit board means, in particular, a projection in a direction parallel to the longitudinal axis of the printed circuit board and therefore also parallel to the longitudinal axis of the sensor. The ring magnet bears against the at least one bearing surface in the assembled state of the magnetic field sensor.

[0022] A further increase in the precision of the alignment of the ring magnet and the support sleeve can be achieved when, according to another advantageous improvement of the invention, the support sleeve has at least one rib extending in the axial direction, i.e., in a direction parallel to the longitudinal axis of the sensor, in a region of the outer wall of the support sleeve facing the end of the printed circuit board. Preferably, a plurality of such ribs are provided on the support sleeve, for example, four ribs. It is particularly advantageous for the rib or ribs to be adjacent to the axial stop of the support sleeve, i.e., for example, for them to be arranged from the axial stop of the support sleeve on the outer wall region of the support sleeve.The ring magnet comes into contact in particular around the outer wall region of the support sleeve having the rib or ribs.

[0023] In particular, precise orientation of the ring magnet on the support sleeve in the radial direction, i.e., perpendicular to the longitudinal axis of the sensor, can be facilitated when, according to an advantageous improvement of the invention, the length of at least one rib is less than the length of the ring magnet. Preferably, the length of at least one rib is less than half the length of the ring magnet, so that a particularly good orientation of the ring magnet can be achieved.

[0024] According to another advantageous improvement of the invention, the Hall element is a surface-mountable component and has a Hall effect integrated circuit. Preferably, the Hall element is a Hall effect integrated circuit, and therefore, in particular, a surface-mountable Hall effect integrated circuit. A surface-mountable component is also called an SMD (surface-mounted device). The Hall effect integrated circuit is an integrated circuit (IC).

[0025] The second objective above is achieved according to the invention by means of a method for manufacturing a magnetic field sensor, firstly a Hall element being mounted on a printed circuit board surface of a printed circuit board end piece in a SMD process; secondly either a support sleeve being threaded onto the printed circuit board end piece having the Hall element and a ring magnet being threaded onto the support sleeve or secondly the support sleeve, onto which the ring magnet is threaded, being threaded onto the printed circuit board end piece having the Hall element; secondly a sensor structural unit having the Hall element, the printed circuit board end piece, the support sleeve and the ring magnet being inserted into a sensor housing; and secondly in addition to a sealing mass being introduced into the sensor housing. The method is in particular a method for manufacturing a magnetic field sensor described above. If, according to the variant of the method, the support sleeve, onto which the ring magnet is threaded, is threaded onto the end portion of the printed circuit board having the Hall element, then the support sleeve carrying the ring magnet can be assembled into a preliminary assembly, and this preliminary assembly can then be threaded onto the printed circuit board already as a unit.

[0026] The method according to the invention offers, in particular and advantageously, the possibility of providing a surface-mountable component for the Hall element, without any risk of damage to the Hall element during the other process steps for manufacturing the magnetic field sensor, in particular a risk of damage from contact between the Hall element and the printed circuit board. The support sleeve is preferably threaded onto the end portion of the printed circuit board containing the Hall element until it rests against an axial stop on the printed circuit board. Preferably, the ring magnet is threaded onto the support sleeve until it rests against an axial stop on the support sleeve.

[0027] The sensor housing is in particular a cylindrical sensor housing. Preferably, the sensor housing is pot-shaped. In particular, the sensor structural unit may further comprise not only the printed circuit board end portion but also the printed circuit board as a whole. The sensor structural unit is in particular inserted into the sensor housing. The sensor housing preferably receives the printed circuit board completely, i.e., along its entire length, so that the printed circuit board and, with it, the components arranged on and within it, are particularly well protected within the magnetic field sensor. The sealing material may, for example, be what is known as an encapsulation or an encapsulation compound.

[0028] According to an advantageous improvement of the invention, the sensor housing is closed at a second end opposite the first end of the sensor housing which has the Hall element. This results in particularly high protection of the components arranged within the sensor housing, especially components arranged on and at the printed circuit board, such as the Hall element and the ring magnet, and thus makes it difficult to tamper with the magnetic field sensor. The sensor housing can be closed, for example, using a plug-in socket which also allows connection, for example, to an electrical connection line to a tachograph.

[0029] The invention also includes combinations of individual features of the embodiments described. The invention also relates to variants of the method according to the invention for manufacturing a magnetic field sensor, which have characteristics as described above in relation to the variants of the magnetic field sensor according to the invention and vice versa.

[0030] Examples of embodiments of the invention are described in more detail below with the help of the schematic representations and sketches in the drawing.

[0031] In the figures:

[0032] [Fig-1] [Fig.1] illustrates a magnetic field sensor in a side view,

[0033] [Fig.2] [Fig.2] illustrates an assembly of a magnetic field sensor in a fragmented representation

[0034] [Fig.3] [Fig.3] illustrates the entire [Fig.2] in an assembled state in a side view,

[0035] [Fig.4] [Fig.4] illustrates a first cross-sectional view of the assembly according to [Fig.3],

[0036] [Fig.5] [Fig.5] illustrates a second cross-sectional view of the assembly according to [Fig.3],

[0037] [Fig. 6] [Fig. 6] illustrates an enlarged cross-sectional view of part of the whole of the [Fig.3] in a state installed in a magnetic field sensor,

[0038] [Fig.7] [Fig.7] illustrates another cross-sectional view of the assembly according to figures 3 and 6,

[0039] [Fig.8], [Fig.9], [Fig.10], [Fig.11] Figures 8 to 11 illustrate a support sleeve in different perspective views,

[0040] [Fig. 12] [Fig. 12] illustrates a first side view of the support sleeve according to figures 8 to 11,

[0041] [Fig. 13] [Fig. 13] illustrates a second side view of the support sleeve according to figures 8 to 11,

[0042] [Fig. 14], [Fig. 15], [Fig. 16], [Fig. 17] Figures 14 to 17 illustrate the assembly according to Figures 3 and 6 in different assembled states.

[0043] Corresponding elements are respectively given the same reference symbols in all figures.

[0044] Fig. 1 illustrates in a perspective side view a magnetic field sensor 1 having a sensor head 2 at a first end of a sensor housing 4 and having a plug-in base 6 at a second end of a sensor housing 8, opposite the first end of the sensor housing 4. The magnetic field sensor 1 is made in the shape of a bar and has a longitudinal sensor axis S.

[0045] Figure 2 illustrates in an exploded view an assembly 10 arranged inside a magnetic field sensor, for example, a magnetic field sensor 1 as illustrated in Figure 1. The assembly 10, which can, for example Also called the sensor structural unit, it comprises a printed circuit board 12, a support sleeve 14, and a ring magnet 16. The printed circuit board 12 is an elongated printed circuit board with a longitudinal extension and a longitudinal printed circuit board axis L. A printed circuit board end portion 18 of the printed circuit board 12 forms part of the sensor head 2 together with the support sleeve 14 and the ring magnet 16 in an assembled state of the magnetic field sensor 1. In addition, a Hall effect sensor 22 is arranged in the assembly 10 on a printed circuit board surface 20 of the printed circuit board end portion 18.

[0046] For greater clarity, the assembly 10 shown in an exploded view in [Fig. 2] is shown in [Fig. 3] in a side view in an assembled state. [Fig. 4], which shows a first cross-sectional view of the assembly of [Fig. 3] in a section along line AA, and [Fig. 5], which shows a second cross-sectional view of the assembly of [Fig. 3] in another section along line DD, demonstrate that the support sleeve 14 is arranged on the printed circuit board 12 so as to engage at least partially around the end portion of the printed circuit board 18 comprising the Hall element 22.

[0047] The support sleeve 14 has a support sleeve recess 26 in a direction diverted from one end of the printed circuit board 24 of the printed circuit board terminal portion 18 parallel to the printed circuit board 12 and therefore also parallel to the longitudinal axis of the printed circuit board L. The support sleeve recess 26 is made such that it protrudes at least one outer contour 28 of the Hall element 22 in a plane perpendicular to the printed circuit board 12 and is open at one end of the support sleeve 30 of the support sleeve 14 which is opposite the printed circuit board end 24 of the printed circuit board terminal portion 18 presenting the Hall element 22.

[0048] The support sleeve recess 26 forms a tunnel in the support sleeve 14. The tunnel allows in cross section an arrangement or at least a socket entry of the Hall element 22 and of the printed circuit board terminal part 18, on which the Hall element 22 is arranged, inside the support sleeve 14, respectively through it. Furthermore, during the manufacture of the magnetic field sensor 1, and while filling the sensor head 2 with a sealing mass, the sealing mass can flow through the tunnel to the Hall element 22 and the printed circuit board end 24 at the end of the sensor head 2 in the region of the first end of the sensor housing 4. The ring magnet 16 is arranged on the support sleeve 14 such that the Hall element 22 is arranged at least partially inside the ring magnet 16.

[0049] Figure 6 illustrates an enlarged cross-sectional view of a portion of the assembly 10 of Figure 3 in a state installed in a magnetic field sensor 1. It should be noted here that the printed circuit board terminal 18 comprising the Hall element 22 and the support sleeve 14 as well as the ring magnet 16 is arranged in the sensor head 2 and inside a sensor housing 32 of the magnetic field sensor 1. The sensor housing 32 is pot-shaped at the first end of the sensor housing 4 in the region of the sensor head 2. The sensor housing 32 is therefore closed at the first end of the sensor housing 4 and made in one piece, i.e. as a single component.

[0050] The sensor head 2 has at one end, i.e., in the region of the first end of the sensor housing 4, an external thread 33, which serves to screw the magnetic field sensor 1, for example, into a transmission housing of a drivetrain in a motor vehicle. The dimensions of the external thread 33 may be predetermined, for example, due to predetermined installation conditions, in particular, for example, the dimensions of a corresponding internal thread in the transmission housing.The wall thickness a of the sensor housing, in particular of the sensor head 2, especially in a region of a thread clearance groove and / or in a region in the immediate vicinity of a thread end, which regions are frequently subjected to particularly high mechanical stress, is relatively large for predefined dimensions of the external thread 33, because the support sleeve 14 is devoid of external spacing fingers, for example.

[0051] A cross-sectional view rotated 90° around the longitudinal axis of the printed circuit board L of the arrangement illustrated in [Fig. 6] is shown, without the sensor housing 32, in [Fig. 7]. In this case, a rear side of the printed circuit board 12 comprising the printed circuit board terminal portion 18 is shown, which rear side is opposite a printed circuit board surface 20 presenting the Hall element 22, so that the Hall element 22 is not shown (more precisely: is not visible) in [Fig. 7].

[0052] Figures 8 and 9 illustrate the support sleeve 14 in various perspective views, and Figures 10 and 11 show perspective cross-sectional views of the support sleeve 14. It should be noted that the support sleeve recess 26 is a through recess of the support sleeve 14 and forms an inner contour 34 of the support sleeve 14. The inner contour 34 of the support sleeve 14 has two opposing longitudinal grooves 36, 38. The longitudinal grooves 36, 38 receive the printed circuit board 12 between them, namely, in particular, the end portion of the printed circuit board 18 in the illustrated embodiments (see [Fig. 5]). The longitudinal grooves 36, 38 have, At the level of their respective groove bottoms, a longitudinal rib 40 is present in the embodiments illustrated here. Furthermore, the respective groove sides of the longitudinal grooves 36, 38 are also provided with corresponding longitudinal ribs 42, 44.

[0053] Figure 12 illustrates a first side view of the support sleeve 14 in the direction of the longitudinal axis of the sensor S and therefore also the longitudinal axis of the printed circuit board L, and Figure 13 illustrates a second side view of the support sleeve 14 in the opposite direction. The support sleeve 14 has an axial support sleeve stop 46 at one end of the support sleeve 30 opposite the end of the printed circuit board 24. The axial support sleeve stop 46 is annular and has a plurality of overflow channels 50 on its outer periphery 48. In the embodiments illustrated here, the axial support sleeve stop 46 has four bearing surfaces 52 projecting towards the end of the printed circuit board 24.The bearing surfaces 52 serve in particular to adjust a homogeneous bonding gap between the support sleeve 14 and the ring magnet 16, in particular between the axial stop of the support sleeve 46 of the support sleeve 14 and a corresponding front surface of the ring magnet 16, in a bonded assembly of the support sleeve 14 and the ring magnet 16.

[0054] Furthermore, the support sleeve 14 has several ribs 56 extending in the axial direction, i.e., parallel to the longitudinal axis of the printed circuit board L and correspondingly also parallel to the longitudinal axis of the sensor S, in a region of the outer wall of the support sleeve 54 facing the end of the printed circuit board 24 (see [Fig. 8]). The length of the ribs 56 is less than the length of the ring magnet 16. In particular, in the embodiment illustrated here, the length of the ribs 56 is less than half the length of the ring magnet 16.The ribs 56 serve in particular to adjust a homogeneous bonding gap between the support sleeve 14 and the ring magnet 16, in particular between the outer wall region of the support sleeve 54 of the support sleeve 14 and a corresponding inner wall region of the ring magnet 16, in a bonded assembly of the support sleeve 14 and the ring magnet 16. Due to the presence of relatively short ribs 56, for example ribs 56 which are at least less than half the length of the ring magnet 16, as in the present embodiment, an exact orientation of a front surface of the ring magnet 16 perpendicular to the printed circuit board 12 and the Hall element 22 is further made possible, so that the measurement properties of the magnetic field sensor 1 can be further optimized.

[0055] Ribs 56 made in a short manner compared to the length of the ring magnet 16 allow that an angular deviation, possibly resulting during a manufacture of the ring magnet 16, with respect to an angle of 90° between a front surface of the ring magnet 16 and the median axis of an internal recess, for example of an internal bore, of the ring magnet 16 can be compensated, an essentially, i.e. in large regions, uniform bonding gap between the outer wall region of the support sleeve 54 and the corresponding inner wall region of the ring magnet 16 can however be guaranteed. Therefore, an inclination of the front surfaces of the ring magnet 16, in particular of the front surface of the ring magnet 16 turned towards the end of the printed circuit board 24, in the region of which the Hall element 22 is arranged, can be avoided.The measurement properties of the magnetic field sensor 1 can thus be improved.

[0056] The support sleeve 14 rests, by an axial bearing surface 58 (see [Fig.9]) against an axial stop of printed circuit board 60 (see [Fig.7]).

[0057] A method for manufacturing a magnetic field sensor 1 is described below with reference to Figures 14 to 17. In this case, a Hall effect sensor 22 is first mounted on a printed circuit board surface 20 of a printed circuit board end 18 of a printed circuit board 12 in a surface-mount technology (SMT) process (see [Fig. 14]). Then, a support sleeve 14 is threaded onto the printed circuit board end 18 bearing the Hall effect sensor 22 (see [Fig. 15]). In particular, the support sleeve 14 can be threaded and optionally pressed to a defined depth, in particular up to an axial stop on the printed circuit board 60. Then, the support sleeve 14 is preferably glued to the printed circuit board 12.

[0058] Next, a ring magnet 16 is threaded onto the support sleeve 14 until the ring magnet 16, in particular a front surface of the ring magnet 16, bears against an axial stop 46 of the support sleeve 14, in particular against bearing surfaces 52 of the axial stop 46 of the support sleeve 14 (see Figures 15 and 16). Preferably, the ring magnet 16 is glued to the support sleeve 14. To better illustrate the arrangement and in particular the Hall element 22 with respect to the support sleeve 14, the ring magnet 16 is not shown in [Fig. 17] and the support sleeve 14 is shown in a dashed representation.

[0059] A sensor structural unit corresponding to the assembly 10 illustrated in [Fig. 2] and comprising the Hall element 22, the printed circuit board end portion 18, the support sleeve 14, and the ring magnet 16 is inserted into a pot-shaped sensor housing 32 (see [Fig. 6]). Then, a sealing mass is introduced into the sensor housing 32. In addition, the sensor housing 32 is closed by means of a plug-in base 6 (see [Fig.1]) at a second end of the sensor housing 8 opposite to the first end of the sensor housing 4 having the Hall element 22.

Claims

Demands

1. Magnetic field sensor (1) comprising a sensor head (2), the sensor head (2) having a printed circuit board end portion (18) of a printed circuit board (12) and, at the printed circuit board end portion (18), a Hall element (22) and a ring magnet (16), characterized in that the Hall element (22) is arranged on a printed circuit board surface (20) of the printed circuit board end portion (18) and in that a support sleeve (14) is arranged on the printed circuit board (12) so as to engage at least partially around the printed circuit board end portion (18) comprising the Hall element (22),the support sleeve (14) having a support sleeve recess (26) at least in one direction away from a printed circuit board end (24) of the printed circuit board end portion (18) parallel to the printed circuit board (12), which support sleeve recess extends at least one outer contour (28) of the Hall element (22) in a plane perpendicular to the printed circuit board (12) and is open at a support sleeve end (30) of the support sleeve (14) that is opposite the printed circuit board end (24) of the printed circuit board end portion (18) having the Hall element (22), and the ring magnet (16) being arranged on the support sleeve (14) such that the Hall element (22) is arranged at least partially inside the ring magnet (16).

2. Magnetic field sensor (1) according to claim 1, characterized in that the support sleeve recess (26) is a through recess of the support sleeve (14) and forms an inner contour (34) of the support sleeve (14), the inner contour (34) having two facing longitudinal grooves (36, 38), which receive the printed circuit board (12) between them.

3. Magnetic field sensor (1) according to claim 2, characterized in that at least one of the longitudinal grooves (36, 28) has at least one lug or longitudinal rib (40).

4. Magnetic field sensor (1) according to any one of the preceding claims, characterized in that the printed circuit board (12) has an axial stop of the printed circuit board (60) and in that the support sleeve (14) bears against the axial stop of the printed circuit board (60).

5. Magnetic field sensor (1) according to any one of the preceding claims, characterized in that the support sleeve (14) has an axial support sleeve stop (46) at one end of the support sleeve (30) opposite the end of the printed circuit board (24).

6. Magnetic field sensor (1) according to claim 5, characterized in that the axial stop of the support sleeve (46) is annular in form and has on its outer periphery (48) at least one overflow channel (50).

7. Magnetic field sensor (1) according to any one of claims 5 or 6, characterized in that the axial stop of the support sleeve (46) has at least one bearing surface (52) projecting axially towards the end of the printed circuit board (24).

8. Magnetic field sensor (1) according to any one of the preceding claims, characterized in that the support sleeve (14) has at least one rib (56) extending in the axial direction in an outer wall region of the support sleeve (54) facing the end of the printed circuit board (24).

9. Magnetic field sensor (1) according to claim 8, characterized in that the length of at least one rib (56) is less than the length of the ring magnet (16).

10. Magnetic field sensor (1) according to any one of the preceding claims, characterized in that the Hall element (22) is an SMD type component and has a Hall effect integrated circuit.

11. A method for manufacturing a magnetic field sensor (1), characterized in that a Hall element (22) is mounted on a printed circuit board surface (20) of a printed circuit board terminal (18) of a printed circuit board (12) in an SMD process, - in that either a support sleeve (14) is threaded onto the printed circuit board end portion (18) having the Hall element (22) and a ring magnet (16) is threaded onto the support sleeve (14) or the support sleeve (14), onto which the ring magnet (16) is threaded, is threaded onto the printed circuit board end portion (18) having the Hall element (22), - in that a sensor structural unit having the Hall element (22), the printed circuit board end portion (18), the support sleeve (14) and the ring magnet (16) is inserted into a sensor housing (32), - in that a sealing mass is introduced into the sensor housing (32).

12. Method according to claim 11, characterized in that the sensor housing (32) is closed at a second sensor housing end (8) opposite to the first sensor housing end (4) having the Hall element (22).

Images