Method for producing a wiegand sensor, and wiegand sensor

Abstract

The invention relates to a method for producing a Wiegand sensor (10), wherein a Wiegand wire (50) is inserted into a base part (30) of a housing (20); a cover (40) of the housing (20) is joined to the base part (30) in a joining direction (F); the cover (40) is bonded, in particular materially, to the base part (30), and at the same time the cover (40) is bonded, in particular materially, to the Wiegand wire (50). The invention also relates to a Wiegand sensor (10), comprising a housing (20) and a Wiegand wire (50) inserted into the housing (20), which sensor is produced by way of the method according to the invention.

Description

[0001] Method for manufacturing a Wiegand sensor and Wiegand sensor

[0002] Description:

[0003] The invention relates to a method for producing a Wiegand sensor. The invention also relates to a Wiegand sensor produced using the method according to the invention.

[0004] Wiegand sensors, also known as pulse wire sensors, contain a Wiegand wire as their main component. Such a Wiegand wire comprises parallel soft magnetic and hard magnetic areas, thus exhibiting hysteresis with pronounced jumps. A change in the magnetization of the Wiegand wire causes a voltage pulse in a nearby coil. Wiegand sensors are primarily used for motion detection using rotary encoders or other pulse generators, as well as for encoding identification devices in access control systems.

[0005] Document DE 102012 012 874 B4 discloses a Wiegand sensor of this type for determining the number of revolutions of a rotatably mounted shaft. The Wiegand sensor comprises a Wiegand wire and signal processing means for evaluating the voltage pulses generated by the Wiegand wire.

[0006] Wiegand sensors known from use have a housing that encloses the Wiegand wire and the signal processing means. The Wiegand wire, as a central component, is connected to the housing at both ends, for example, by adhesive bonding. The adhesive used allows the Wiegand wire to expand in length, for example, due to temperature changes. At the same time, the bonding prevents particles from penetrating sensitive areas of the housing. This method for manufacturing a Wiegand sensor requires a time-consuming process step due to the long curing times of the adhesive, making integration into an automated manufacturing process difficult.

[0007] DE 102005 060 519 A1 discloses a rotation angle sensor and a rotation angle sensor system. The rotation angle sensor enables the determination of the rotation angle of a rotating shaft. DE 102015 101 248 A1 discloses a magnet-based rotation angle measuring system. The rotation angle measuring system is used to detect the rotational movement of a drive shaft and comprises a stationary sensor unit,

[0008] DE 102008 000 517 A1 discloses a method for producing a pressure-tight joint between a metallic component and a plastic component. This involves introducing a quantity of heat into the plastic material of the plastic component.

[0009] The invention is based on the object of developing a method for producing a Wiegand sensor, in particular to accelerate the fastening of the Wiegand wire in the housing.

[0010] The object is achieved by a method for producing a Wiegand sensor having the features specified in claim 1. Advantageous embodiments and further developments are the subject of the subclaims. The object is also achieved by a Wiegand sensor having the features specified in claim 11.

[0011] In a method according to the invention for manufacturing a Wiegand sensor, a Wiegand wire is inserted into a base part of a housing. Subsequently, a cover of the housing is joined to the base part in a joining direction. The cover is then connected to the base part, and simultaneously, the cover is connected to the Wiegand wire. Preferably, the cover is integrally bonded to the base part.

[0012] The cover and base are preferably made of plastic. The Wiegand wire is preferably made of a metallic alloy. The method according to the invention significantly simplifies and shortens the process step for attaching the Wiegand wire. Integration into an automated manufacturing process is also possible.

[0013] Preferably, the cover is firmly connected to the Wiegand wire.

[0014] According to a preferred embodiment of the invention, the cover is joined to the base part by ultrasonic welding. During ultrasonic welding, vibrations are applied to the cover and the base part in the joining direction or at right angles to the joining direction. The cover and the base part are heated and melt locally. The melted areas of the cover and the base part bond and, after cooling and solidifying, are integrally bonded to one another. A circumferential weld seam forms between the cover and the base part. This seals the housing from the outside and prevents particles from penetrating the housing.

[0015] According to a preferred embodiment of the invention, the cover is bonded to the Wiegand wire. Vibrations are applied to the cover and the Wiegand wire in the joining direction or at right angles to the joining direction. This causes the cover to melt locally. The melted areas of the cover flow around the Wiegand wire and bond to the surface of the Wiegand wire. After cooling and solidifying, the cover and the Wiegand wire are firmly bonded.

[0016] According to an advantageous embodiment of the invention, the cover has a plate and a projection protruding from the plate in the joining direction. The cover is designed such that when the cover is joined to the base part, the plate comes into contact with the base part and the projection comes into contact with the Wiegand wire. The plate is connected to the base part and the projection is connected to the Wiegand wire. The projection protrudes into the base part and comes into contact with the Wiegand wire, which is located inside the base part. The connection of the plate to the base part seals the housing to the outside, thereby preventing particles from penetrating the housing.

[0017] According to an advantageous development of the invention, the projection has at least one sacrificial edge, which is arranged in an end region of the projection facing away from the plate. The at least one sacrificial edge is designed such that when the cover is joined to the base part, the sacrificial edge comes into contact with the Wiegand wire, and when the cover is connected to the Wiegand wire, the sacrificial edge melts and flows around the Wiegand wire. This creates a material bond between the projection and the Wiegand wire.

[0018] According to an advantageous embodiment of the invention, the projection has at least two sacrificial edges, which are arranged offset from one another in an axial direction. The axial direction runs perpendicular to the joining direction and parallel to a central axis of the Wiegand wire. According to another advantageous embodiment of the invention, the projection has at least two sacrificial edges, which are arranged offset from one another in a transverse direction such that when the cover is joined to the base part, the sacrificial edges surround the Wiegand wire. The transverse direction runs perpendicular to the joining direction and perpendicular to a central axis of the Wiegand wire.

[0019] According to a preferred embodiment of the invention, the cover is designed such that when connecting the projection to the Wiegand wire, the projection is additionally connected to the base part, and / or the Wiegand wire is additionally connected to the base part. Preferably, the projection is connected to the base part by a material fit. Preferably, the Wiegand wire is connected to the base part by a material fit.

[0020] According to an advantageous embodiment of the invention, the Wiegand wire is integrally connected to the cover at only one end, while the opposite end of the Wiegand wire is mounted so that it can move axially relative to the cover. This allows for longitudinal expansion of the Wiegand wire, particularly during temperature changes.

[0021] A Wiegand sensor according to the invention comprises a housing and a Wiegand wire inserted into the housing, wherein the Wiegand sensor is manufactured using the method according to the invention. A Wiegand sensor according to the invention can be manufactured in a relatively short process time. The housing is sealed to the outside, preventing particles from penetrating the housing.

[0022] The invention is not limited to the combination of features in the claims. Further possible combinations of claims and / or individual claim features and / or features of the description and / or the figures will become apparent to those skilled in the art, particularly from the task and / or the problem posed by comparison with the prior art. The invention will now be explained in more detail with reference to figures. The invention is not limited to the exemplary embodiments shown in the figures. The figures represent the subject matter of the invention only schematically. They show:

[0023] Figure 1 : a perspective view of a Wiegand sensor,

[0024] Figure 2: a top view of the Wiegand sensor from Figure 1 ,

[0025] Figure 3: a sectional view along the section line AA from Figure 2 during joining,

[0026] Figure 4: an enlarged view of area B from Figure 3 and

[0027] Figure 5: a sectional view along section line AA from Figure 2 after joining.

[0028] Figure 1 shows a perspective view of a Wiegand sensor 10 manufactured according to the method according to the invention. The Wiegand sensor 10 comprises a housing 20 and a Wiegand wire 50 inserted into the housing 20, which is concealed in this illustration. The housing 20 comprises a base part 30 and a cover 40. The base part 30 and the cover 40 are welded together along a weld seam 24. The base part 30 encloses a trough-shaped receiving area. The receiving area of ​​the base part 30 serves to accommodate the Wiegand wire 50 and other components.

[0029] The housing 20 is approximately cuboid-shaped and has a first front side, a second front side, a first end side, a second end side, a base side, and a cover side. The front sides are arranged opposite one another in a transverse direction Q. Furthermore, the end sides are arranged opposite one another in an axial direction X. The base side is arranged opposite the cover side in a joining direction F. The axial direction X runs perpendicular to the joining direction F. The transverse direction Y runs perpendicular to the joining direction F and perpendicular to the axial direction X.

[0030] The Wiegand sensor 10 comprises a plurality of connection elements 22 for contacting electronic components, which are arranged in the receiving area of ​​the base part 30. The connection elements 22 are designed as metallic contacts that extend through the base part 30. Figure 2 shows a plan view of the Wiegand sensor 10 from Figure 1. The cover side of the housing 20 is largely formed by the lid 40. The front sides, the end sides, and the bottom side are largely or exclusively formed by the base part 30. The weld seam 24 is located largely on the cover side of the housing 20. The connection elements 22 protrude from the front sides of the housing 20.

[0031] Figure 3 shows a sectional view of the Wiegand sensor 10 along the section line AA from Figure 2 during the joining of the cover 40 to the base part 30. During the manufacture of the Wiegand sensor 10, the cover 40 is joined to the base part 30 in the joining direction F, i.e., moved toward the base part 30. In this illustration, the Wiegand sensor 10 is not yet fully manufactured; the cover 40 is still removed from the base part 30.

[0032] The Wiegand wire 50 is inserted linearly into the receiving area of ​​the base part 30 of the housing 20. A central axis of the Wiegand wire 50 extends in the axial direction X. The Wiegand sensor 10 comprises, in addition to other components not shown here, a coil 32, two ferrite beads 34, and a glass tube 36. The ferrite beads 34 are arranged on both sides of the coil 32 in the axial direction X. The glass tube 36 passes through the ferrite beads 34 and the coil 32 in the axial direction X. The Wiegand wire 50 is arranged within the glass tube 36. The glass tube 36 thus coaxially surrounds the Wiegand wire 50. The ferrite beads 34 and the coil 32 coaxially surround the glass tube 36 and the Wiegand wire 50.

[0033] The cover 40 has a plate 41 and a projection 42. The projection 42 protrudes from the plate 41 in the joining direction F. When the cover 40 is joined to the base part 30, the plate 41 comes into contact with the base part 30. When the cover 40 is joined to the base part 30, the projection 42 comes into contact with the Wiegand wire 50.

[0034] Figure 4 shows an enlarged view of area B of the Wiegand sensor 10 from Figure 3, i.e., also during the joining of the cover 40 to the base part 30. The projection 42 of the cover 40 has two sacrificial edges 44. The sacrificial edges 44 are arranged in an end region of the projection 42 facing away from the plate 41. In this case, the sacrificial edges 44 are each formed as a conical convexity and protrude away from the plate 41 in the joining direction F. The sacrificial edges 44 are arranged offset from one another in an axial direction X. When the cover 40 is joined to the base part 30, the sacrificial edges 44 of the projection 42 come into contact with the Wiegand wire 50. Figure 5 shows a sectional view along the section line AA from Figure 2 after joining, of the cover 40 to the base part 30. During the manufacture of the Wiegand sensor 10, as already mentioned, the cover 40 is joined to the base part 30 in the joining direction F, i.e. moved towards the base part 30.In this illustration, the Wiegand sensor 10 is finished.

[0035] When the cover 40 is joined to the base part 30, the plate 41 comes into contact with the base part 30. The plate 41 is bonded to the base part 30 by ultrasonic welding. The circumferential weld seam 24 is formed between the plate 41 of the cover 40 and the base part 30. When the cover 40 is joined to the base part 30, the cover 40 is bonded to the base part 30 by ultrasonic welding.

[0036] When the cover 40 is joined to the base part 30, the projection 42 also comes into contact with the Wiegand wire 50. In the process, the projection 42 of the cover 40 is glued to the Wiegand wire 50. When the projection 42 of the cover 40 is connected to the Wiegand wire 50, the sacrificial edges 44 melt and flow around the Wiegand wire 50. When the cover 40 is joined to the base part 30, the cover 40 is glued to the Wiegand wire 50.

[0037] The melting sacrificial edges 44 also flow onto the base part 30 in the receiving area. When the projection 42 of the cover 40 is connected to the Wiegand wire 50, the projection 42 is thus additionally connected to the base part 30. Likewise, the Wiegand wire 50 is additionally connected to the base part 30.

[0038] The Wiegand wire 50 is integrally connected to the cover 40 and the base part 30 only in one axial end region. The end region of the Wiegand wire 50 opposite in the axial direction X is mounted so as to be movable relative to the cover 40 in the axial direction X. This mounting is achieved by the glass tube 36 and allows the Wiegand wire 50 to expand in the axial direction X, particularly during temperature changes.

[0039] 10 Wiegand sensors

[0040] 20 housings

[0041] 22 connecting element

[0042] 24 Weld seam

[0043] 30 base part

[0044] 32 coil

[0045] 34 Ferrite bead

[0046] 36 glass tube

[0047] 40 lids

[0048] 41 plate

[0049] 42 lead

[0050] 44 Sacrificial Edge

[0051] 50 Wiegand wire

[0052] F Joining direction

[0053] Q transverse direction

[0054] X axial direction

Claims

Patent claims:

1. Method for manufacturing a Wiegand sensor (10), wherein a Wiegand wire (50) is inserted into a base part (30) of a housing (20); a cover (40) of the housing (20) is joined to the base part (30) in a joining direction (F); the cover (40) is connected to the base part (30), in particular by a material bond, and at the same time the cover (40) is connected to the Wiegand wire (50).

2. Method according to one of the preceding claims, characterized in that the lid (40) is joined to the base part (30) in a materially bonded manner.

3. Method according to one of the preceding claims, characterized in that the lid (40) is joined to the base part (30) by means of ultrasonic welding.

4. Method according to one of the preceding claims, characterized in that the lid (40) is glued to the Wiegand wire (50).

5. Method according to one of the preceding claims, characterized in that the cover (40) has a plate (41) and a projection (42) extending from the plate (41) in the joining direction (F), and that the cover (40) is designed such that when the cover (40) is joined to the base part (30), the plate (41) comes into contact with the base part (30) and the projection (42) comes into contact with the Wiegand wire (50), and that the plate (41) is connected to the base part (30), and the projection (42) is connected to the Wiegand wire (50).

6. Method according to claim 5, characterized in that the projection (42) has at least one sacrificial edge (44) which is arranged in an end region of the projection (42) facing away from the plate (41), and that the at least one sacrificial edge (44) is designed such that when the cover (40) is joined to the base part (30) the sacrificial edge (44) comes into contact with the Wiegand wire (50), and that when the cover (40) is joined to the Wiegand wire (50) the sacrificial edge (44) melts and flows around the Wiegand wire (50).

7. Method according to claim 6, characterized in that the projection (42) has at least two sacrificial edges (44) which are arranged offset from each other in an axial direction (X).

8. Method according to claim 6, characterized in that the projection (42) has at least two sacrificial edges (44) which are arranged offset from each other in a transverse direction (Y) such that when the lid (40) is joined to the base part (30) the sacrificial edges (44) surround the Wiegand wire (50).

9. Method according to one of claims 5 to 8, characterized in that the cover (40) is designed such that when connecting the projection (42) with the Wiegand wire (50), the projection (42) is additionally connected to the base part (30), and / or the Wiegand wire (50) is additionally connected to the base part (30).

10. Method according to one of the preceding claims, characterized in that the Wiegand wire (50) is only materially bonded to the lid (40) in one end region, and that the opposite end region of the Wiegand wire (50) is movably mounted relative to the lid (40) in the axial direction (X).

11. Wiegand sensor (10) comprising a housing (20) and a Wiegand wire (50) inserted into the housing (20), manufactured by the method according to one of the preceding claims.

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