Electromagnet

Abstract

Electromagnet, with a coil arrangement (20), a coil body (30) arranged within the coil arrangement (20), and an armature (60) which is movable in the coil body (30) along an armature movement direction defined by the coil body (30), wherein the coil body (30) has a support tube (40) and a plastic material (50), wherein the support tube (40) is at least partially over-molded with the plastic material (50), characterized in that the coil body (30) has a running surface (32) for the armature (60) on the inside and the running surface (32) is formed partly by the support tube (40) and partly by the plastic material (50) located in recesses (42) of the support tube (40).

Description

[0001] The invention relates to an electromagnet having a coil arrangement, a coil body arranged within the coil arrangement, and an armature which is movable in the coil body along an armature movement direction defined by the coil body.

[0002] Electromagnets are known in the prior art in which the armature is guided in an armature guide tube. The plastic coil body is mounted on the armature guide tube. A disadvantage of this design is that a sliding film or coating is required to ensure a long service life, which complicates and increases the cost of manufacturing.

[0003] The generic document DE 10 2005 000 985 B4 discloses a coil receiving device, in particular for a solenoid valve, comprising a coil body (2) and a support or carrier element (4) which is formed integrally with the coil body (2), wherein the coil body (2) and the carrier element (4) are formed substantially hollow-cylindrically in order to receive a magnetic core (6), the carrier element (4) is provided at least in the region of the magnetic core (6) to be received, the coil body (2) forms the inner surface (8) of the coil receiving device at least in the region of the magnetic core (6) to be received, the hollow-cylindrical carrier element (4) has a plurality of recesses or openings (10) distributed over the circumference and wherein the coil body (2) extends through the openings (10) of the carrier element (4).

[0004] The document DE 10 2012 214 698 A1 discloses a pole tube for an actuator device with at least one magnet, wherein the pole tube is provided with a coating radially inside.

[0005] The document DE 10 2013 226 619 A1 discloses a method for producing a pole tube with two magnetic pole tube components and with an amagnetic ring arranged axially between the pole tube components, for an electromagnet, in particular for a solenoid valve of an automatic transmission in a motor vehicle, comprising the following steps: - concentric arrangement and / or centering of the pole tube components and the ring, in particular on a centering mandrel; - positive connection, in particular overmolding and / or casting of an outer surface of the pole tube components and the ring.

[0006] It is therefore the object of the invention to further develop this state of the art.

[0007] This is achieved according to the invention by an electromagnet according to claim 1. Advantageous embodiments can be found, for example, in the subclaims.

[0008] The invention relates to an electromagnet comprising a coil arrangement, a coil former arranged within the coil arrangement, and an armature. The armature is movable within the coil former along a direction of armature movement defined by the coil former.

[0009] The coil arrangement can in particular comprise one or more electrical coils which generate a magnetic field when energized or when subjected to electrical current.

[0010] The armature can be movable in particular in that when the coil arrangement or a number of coils of the coil arrangement are energized, a magnetic field is generated which exerts a force on the armature.

[0011] According to the invention, the coil body comprises a support tube and a plastic material, wherein the support tube is at least partially overmolded with the plastic material.

[0012] The arrangement is chosen so that the armature slides at least partially on the plastic material. This plastic bearing already significantly increases the service life of such electromagnets. Since no sliding film is required, the manufacturing process is easily automated, which reduces manufacturing costs.

[0013] The support tube ensures high stability and high precision of the armature bearing. The inventive proposal reduces bearing constrictions during winding of the coil former and the resulting processing or assembly problems due to dimensional inaccuracies or shrinkage.

[0014] With the help of the inventive proposal, one can now choose from a wider range of materials for the coil body. It is now possible to use plastics that are less heat-resistant and optimized for frictional wear, as well as more cost-effective and injection-moldable, as the material for the coil body, which reduces the manufacturing costs of such electromagnets. The use of the support tube also achieves greater operational reliability, thus lowering the probability of failure in such electromagnets, as the risk of armature jamming is significantly reduced.

[0015] The inventive proposal also allows for a magnetic separation of the support tube from the armature, thus avoiding a magnetic short circuit. This significantly improves the magnetic transition and the overall efficiency of such an electromagnet.

[0016] Cleverly, the coil body is designed as a tubular and / or armature guide tube. This allows adaptation to typical electromagnet or armature shapes.

[0017] The support tube is preferably made of metal. This allows for high stability and easy processing.

[0018] According to the invention, the support tube has a number of recesses. These can ensure a better connection with the plastic material, as the plastic material can pass through them. This accelerates the manufacturing process because the flow path during injection molding of the coil former is reduced. Fiber-reinforced plastic material, for example, glass-fiber-reinforced plastic material, is also used for the production of the coil former, whereby the glass fiber orientation is advantageously swirled in the area of ​​the recesses. By positioning the recesses precisely, the magnetic flux can also be controlled, for example, creating a magnetic separation.

[0019] The support tube can be stamped and rolled, allowing for simple production.

[0020] According to an embodiment not covered by claim 1, the support tube can be completely overmolded with the plastic material. This allows the support tube to be completely embedded in the plastic material. The armature slides on the plastic material. This significantly increases the service life of such electromagnets.

[0021] According to one design, the support tube can be only partially overmolded with the plastic material. This allows parts of the support tube to be left exposed, for example, to utilize the properties of a metallic or solid surface.

[0022] In particular, the support tube can only be overmolded with the plastic material to the extent that the plastic material is located between the support tube and the coil assembly, as well as in recesses in the support tube. This allows a surface of the support tube to remain exposed radially inward, i.e., toward the armature.

[0023] The coil body has a running surface on the inside for the armature. This can guide and stabilize the armature. It is preferably designed to be abrasion-resistant.

[0024] According to an embodiment not covered by claim 1, the running surface is formed entirely from the plastic material. This allows the properties of the plastic material to be utilized for the running surface.

[0025] According to the invention, the running surface is formed partly by the support tube and partly by the plastic material located in the recesses of the support tube. This allows the properties of both the support tube and the plastic material to be utilized, at least in part.

[0026] According to an embodiment not covered by claim 1, a sliding film is arranged in the support tube, forming a running surface for the anchor. This allows the properties of the running surface to be defined independently of the support tube and the plastic material.

[0027] According to an advantageous embodiment, the electromagnet may further comprise a yoke plate into which the support tube is pressed. The yoke plate can fix and hold the support tube, particularly with regard to its position.

[0028] According to a further development, the support tube is magnetically separated. This allows for magnetic optimization.

[0029] According to one embodiment, the support tube has a tube extension with a pole tube effect. This allows for magnetic and / or mechanical optimization.

[0030] According to one design, the plastic material is fiber-filled. This can stabilize the plastic material. However, it should be noted that when using a support tube, fewer fibers are often needed to achieve the desired or required stability than when using a plastic material alone. The fibers can be swirled through the recesses of the support tube. The fibers can be glass fibers, in particular.

[0031] The support tube can in particular be designed with a puzzle lock to stabilize its shape.

[0032] The recesses in the support tube also allow the magnetic flux to be controlled or optimized. Furthermore, the flow path can be reduced during manufacturing and the effective wall thickness can be adjusted.

[0033] For the plastic material, PPS (polyphenylene sulfide) can be used, for example, which allows for high strength. PA (polyamide), for example, can also be used, which allows for good sliding properties. However, other plastics or a mixture of plastics can also be used.

[0034] The invention is illustrated schematically in the drawing, particularly in one embodiment. Shown are: Fig. 1a an electromagnet according to a first embodiment, Fig. 1b a detailed view of Fig. 1a, Fig. 2a shows part of an electromagnet according to a second embodiment of the invention, Fig. 2b a detailed view of Fig. 2a, Fig. 3 a support tube with yoke plate separately, according to the invention, Fig. 4 a support tube assembled with yoke plate, according to the invention.

[0035] In the figures, identical or corresponding elements are designated by the same reference numerals and are therefore not described again unless expedient. The disclosures contained in the entire description are analogously applicable to identical parts with the same reference numerals or the same component designations. Furthermore, the positional information chosen in the description, such as top, bottom, side, etc., refers to the directly described and illustrated figure and, in the event of a change in position, is to be analogously applied to the new position. Furthermore, individual features or combinations of features from the various embodiments shown and described can represent independent, inventive or inventive solutions in themselves.

[0036] Fig. 1a shows an electromagnet 10 according to a first embodiment, which does not fall under claim 1.

[0037] The electromagnet 10 has a coil arrangement 20. The coil arrangement 20 has a number of electrical coils (not shown in detail) through which a current can be passed to thereby generate a magnetic field.

[0038] A coil body 30 is arranged within the coil assembly 20. Its design will be discussed in more detail below.

[0039] The electromagnet 10 further comprises a core 12. This serves to guide the magnetic field lines of the coil arrangement 20. Furthermore, the electromagnet 10 comprises a housing 14 that encloses the electromagnet 10 on the outside.

[0040] An armature 60 is arranged within the coil former 30. The armature is movable within the coil former 30 along an axis defined by the coil former 30 and also corresponding to a longitudinal axis of the coil former 30. The armature 60 is formed from a magnetic material, so that when the coil assembly 20 is subjected to an electric current, which generates a magnetic field, it is moved by this magnetic field.

[0041] An armature spring 62 is arranged between the core 12 and the armature 60, which preloads the armature 60. The preload is applied in a direction away from the core 12. This thus defines a rest position of the armature 60. If a magnetic field is generated by the coil arrangement 20, the armature 60 is attracted to the core 12.

[0042] The design of the coil body 30 will now be discussed in more detail. This is done with reference to Fig. 1a and also with reference to Fig. 1b, where the Fig. 1b the Fig. 1a shows the area marked with a rectangle and labelled ‘Ib’ in more detail.

[0043] The coil body 30 has a support tube 40. This support tube 40 defines the extension of the coil body 30. It is made of a metallic material and is therefore solid and hard.

[0044] A number of recesses 42 are formed in the support tube 40. These are designed in the form of holes in the wall of the support tube 40. They can be used, for example, to guide the magnetic field lines of the magnetic field generated by the coil arrangement 20.

[0045] The coil body 30 further comprises a plastic material 50. The support tube 40 is overmolded with the plastic material 50.

[0046] As can also be clearly seen in the figures, the plastic material 50 also penetrates into the recesses 42 of the support tube 40. Furthermore, the plastic material 50 is formed radially inside and radially outside of the support tube 40, so that the support tube 40 is completely surrounded by the plastic material 50.

[0047] The plastic material 50 thus defines a running surface 32 of the coil former 30. This running surface 32 guides the armature 60 during its movement. It should be understood that, as an alternative to such an embodiment, a film in the coil former 30 can also define the running surface, or that the plastic material 50 can be arranged only radially outside the support tube 40 and, if appropriate, within the recesses 42. In the latter case, the support tube 40 would define the running surface, if appropriate together with the plastic material 50 located in the recesses 42.

[0048] The illustrated design of the coil former 30 allows the advantages of using a metallic support tube 40 and a plastic material 50 to be combined. The support tube 40 ensures high stability, while the plastic material 50 ensures good processability.

[0049] Overall, a long service life can be achieved thanks to the plastic bearings. Less heat-resistant and friction-wear-optimized plastics, which are more cost-effective and injection-moldable, can be used than with a design without a 40 support tube.

[0050] Furthermore, this results in reduced bearing necking during winding due to processing shrinkage. This allows for increased precision in the armature bearing.

[0051] The design is particularly safety-compliant due to the reinforced armature guide (armature clamp) that prevents collapse. Magnetic separation of the support tube is possible, allowing for improved magnetic transfer without short circuits.

[0052] Furthermore, the production can be easily automated, especially if handling for the yoke plate described below is already available.

[0053] Fig. 2a shows part of the components of an electromagnet 10 according to a second embodiment, which falls under claim 1. Fig. 2b shows a section of Fig. 2a, which in Fig. 2a is marked with a rectangle and labelled “IIb”.

[0054] It is particularly noticeable that, in contrast to the execution according to the Fig. 1a and Fig. 1b the plastic material 50 does not surround the support tube 40 on both sides, but only radially on the outside and inside the recesses 42. This means that the running surface 32 for the armature 60 is not defined by the plastic material 50 alone, but alternately by the support tube 40 and the plastic material 50. This allows other properties for the running surface 32, for example with regard to friction and abrasion resistance, to be achieved.

[0055] Furthermore, the electromagnet 10 has a yoke plate 70. Its use and function will be explained below with reference to the Fig. 3 and Fig. 4 will be described in more detail.

[0056] Fig. Figure 3 shows the support tube 40 and the yoke plate 70 separately. A through-bore 72 is formed in the yoke plate 70, in which the support tube 40 can be accommodated.

[0057] Fig. 4 shows the support tube 40 and the yoke plate 70 in an assembled state. It can be seen that the support tube 40 is received in the through hole 72 of the yoke plate 70.

[0058] The support tube 40 can be advantageously secured by means of the yoke plate 70. This applies regardless of the specific design of the overmolding with the plastic material 50.

[0059] The version with a yoke plate according to the Fig. 3 and Fig. 4 can be used not only in the embodiment shown in the Fig. 2a and Fig. 2b. It can also be used in the embodiment shown in the Fig. 1a and Fig. 1b. This applies even though the yoke plate 70 is in the Fig. 1a and Fig. 1b is not explicitly shown.

[0060] Possible features of the proposal are presented below in a structured manner. The following structured features can be combined with each other in any desired combination and can be included in the claims of the application in any combination. It is clear to the person skilled in the art that the invention already results from the subject matter with the fewest features. In particular, advantageous or possible embodiments, but not the only possible embodiments of the invention, are presented below.

[0061] The invention comprises: An electromagnet, comprising a coil arrangement (20), a coil body (30) arranged within the coil arrangement (20), and an armature (60) which is movable in the coil body (30) along an armature movement direction defined by the coil body (30), wherein the coil body (30) has a support tube (40) and a plastic material (50), wherein the support tube (40) is at least partially overmolded with the plastic material (50).

[0062] The above-mentioned electromagnet, wherein the coil body (30) is tubular and / or designed as an armature guide tube.

[0063] The above-mentioned electromagnet, wherein the support tube (40) is made of metal.

[0064] The above-mentioned electromagnet, wherein the support tube (40) has a number of recesses (42).

[0065] The above-mentioned electromagnet, wherein the support tube (40) is stamped rolled.

[0066] The above-mentioned electromagnet, wherein the support tube (40) is completely overmolded with the plastic material (50).

[0067] The above-mentioned electromagnet, wherein the support tube (40) is only partially overmolded with the plastic material (50).

[0068] The above-mentioned electromagnet, wherein the support tube (40) is only overmolded with the plastic material (50) insofar that the plastic material (50) is located between the support tube (40) and the coil arrangement (20) and in recesses (42) of the support tube (40).

[0069] The above-mentioned electromagnet, wherein the coil body (30) has on the inside a running surface (32) for the armature (60).

[0070] The above-mentioned electromagnet, wherein the running surface (32) is completely formed by the plastic material (50).

[0071] The above-mentioned electromagnet, wherein the running surface (32) is formed partly by the support tube (40) and partly by the plastic material (50) located in the recesses (42) of the support tube (40).

[0072] The above-mentioned electromagnet, wherein a sliding film is arranged in the support tube (40), which forms a running surface (32) for the armature (60).

[0073] The above-mentioned electromagnet, wherein the electromagnet (10) further comprises a yoke plate (70) into which the support tube (40) is pressed.

[0074] The above-mentioned electromagnet, wherein the support tube (40) is magnetically separated.

[0075] The above-mentioned electromagnet, wherein the support tube (40) has a tube extension with a pole tube effect.

[0076] The above-mentioned electromagnet, wherein the plastic material (50) is fiber-filled.

Claims

[1] Electromagnet, comprising a coil arrangement (20), a coil body (30) arranged within the coil arrangement (20), and an armature (60) which is movable in the coil body (30) along an armature movement direction defined by the coil body (30), wherein the coil body (30) has a support tube (40) and a plastic material (50), wherein the support tube (40) is at least partially overmolded with the plastic material (50), characterized by , that the coil body (30) has an inner running surface (32) for the armature (60) and the running surface (32) is formed partly by the support tube (40) and partly by the plastic material (50) located in recesses (42) of the support tube (40). [2] Electromagnet according to claim 1, characterized by , that the coil body (30) is tubular and / or designed as an armature guide tube. [3] Electromagnet according to any one of the preceding claims, characterized by, that the support tube (40) is only partially overmolded with the plastic material (50). [4] Electromagnet according to any one of the preceding claims, characterized by , that the support tube (40) is only overmolded with the plastic material (50) insofar as the plastic material (50) is located between the support tube (40) and the coil arrangement (20) and in recesses (42) of the support tube (40). [5] Electromagnet according to any one of the preceding claims, characterized by , that the electromagnet (10) further comprises a yoke plate (70) into which the support tube (40) is pressed.

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