Method for producing one or more concave cut-outs on a main body which is, in particular, substantially cylindrical, armature, keeper plate, and electromagnetic actuator

Abstract

A method for producing one or more concave cut-outs on a main body, which is in particular substantially cylindrical, more particularly one or more grooves on a magnetic armature, a push rod, or a magnetic keeper plate, includes the following steps: providing a main body, which is in particular substantially cylindrical and has a first axis of rotation, rotating the cylindrical main body around the first axis of rotation in a first rotational direction by means of a lathe, and rotating a striking tool, which is provided with a number of fly cutters, around a second axis of rotation, which extends in parallel and offset in relation to the first axis of rotation in a second rotational direction, which is opposite to the first rotational direction, in such a way that the fly cutter engages in a material-removing manner in the main body to produce the cut-out.

Claims

1. A method for producing one or more concave cut-outs (32) on a cylindrical main body (22) of a magnetic armature (40), a push rod (72), or a magnetic keeper plate (62) made of a magnetic, magnetized or magnetizable material, comprising the following steps: providing the cylindrical main body (22), which has a first axis of rotation (T1); rotating the cylindrical main body (22) around the first axis of rotation (T1) in a first rotational direction by means of a lathe (24); rotating a striking tool (26), which is provided with a number of fly cutters (30), around a second axis of rotation (T2), which extends in parallel and offset in relation to the first axis of rotation (T1) in a second rotational direction, which is opposite to the first rotational direction, so that the fly cutter (30) and the main body (22) primarily move in the same direction within an engagement zone (E), in such a way that the fly cutter (30) engages in a material-removing manner in the main body (22) to produce the one or more concave cut-outs (32); and moving the striking tool (26) in relation to the cylindrical main body (22) along the second axis of rotation (T2), wherein the one or more concave cut-outs (32) comprise a plurality of concave cut-outs (32), and wherein a speed at which the striking tool (26) is moved along the second axis of rotation (T2) is selected in such a way that two adjacent ones of the plurality of concave cut-outs (32) merge into one another without interruption, so that a groove (34) is formed, which consists of a plurality of merging ones of the concave cut-outs (32).

2. The method as claimed in claim 1, characterized in that the cylindrical main body (22) is rotated at a first speed (n1) and the striking tool (26) is rotated at a second speed (n2), wherein the first speed (n1) and the second speed (n2) are equal or have an integer ratio to one another.

3. The method as claimed in claim 1, characterized in that the cylindrical main body (22) is rotated at a first speed (n1) and the striking tool (26) is rotated at a second speed (n2), wherein the first speed (n1) and the second speed (n2) differ from one another by a difference (Δn).

Description

(1) Exemplary embodiments of the invention are explained in greater detail hereafter with reference to the appended drawings. In the figures

(2) FIG. 1 shows a schematic illustration of polygon turning known from the prior art,

(3) FIG. 2 shows a schematic illustration of a first embodiment of the method according to the invention,

(4) FIG. 3 shows a schematic illustration of a second embodiment of the method according to the invention,

(5) FIG. 4 shows a schematic illustration of a third embodiment of the method according to the invention, and

(6) FIG. 5 shows a schematic illustration of a first embodiment of an electromagnetic actuator having a magnetic armature which has been machined using the method according to the invention,

(7) FIG. 6 shows a schematic illustration of a second embodiment of an electromagnetic actuator having a magnetic armature which has been machined using the method according to the invention,

(8) FIG. 7 shows a schematic illustration of a keeper plate which has been machined using the method according to the invention,

(9) FIG. 8 shows a sectional illustration of a third embodiment of an electromagnetic actuator having a keeper plate which has been machined using the method according to the invention, and

(10) FIG. 9 shows a perspective illustration of a push rod which has been machined using the method according to the invention.

(11) FIG. 1 shows polygonal turning known from the prior art on the basis of a schematic sketch. For this purpose, a main body 10, which is substantially cylindrical in the original state, is chucked in a lathe 12 and rotated at a first rotational velocity n1 around a first axis of rotation T1. Furthermore, a striking tool 14, which comprises a disk-shaped receptacle body 16, in which two fly cutters 18 are fastened, is rotated at a second rotational velocity n2 around a second axis of rotation T2. The second axis of rotation T2 extends in parallel and offset by the distance D in relation to the first axis of rotation T1. The main body 10 is rotated in a first rotational direction and the striking tool 14 is rotated in a second rotational direction, which are identified by the arrows P1 and P2. With respect to the illustration selected in FIG. 1, the main body 10 and the striking tool 14 are rotated to the right. The distance D between the first axis of rotation T1 and the second axis of rotation T2 is selected so that the fly cutters 18 can engage in a material-removing manner in the main body 10.

(12) Because of the fact that the first rotational direction and the second rotational direction are identical, the main body 10 primarily moves in the opposite direction to the fly cutters 18 in the engagement zone. The engagement zone is to be understood here as the region of the main body 10 which is passed over or passed through by the fly cutters 18. The fly cutters 18 each comprise a cutting face 20, using which they remove the material when engaged with the main body 10. The cutting faces 20 are arranged in relation to the circumference of the receptacle body 16 so that they are moved forward. A flat or slightly curved surface results on the main body 10 because of the material-removing engagement.

(13) The striking tool 14 comprises two fly cutters 18. If the first rotational velocity n1 is equal to the second rotational velocity n2, two of the flat or slightly curved surfaces 21 result on the main body 10. However, in the example shown in FIG. 1, the second rotational velocity n2 is twice the first rotational velocity n1, so that four of the flat or slightly curved surfaces 21 result.

(14) FIG. 2 shows a schematic illustration of a first exemplary embodiment of the method according to the invention. A main body 22, which is typically substantially cylindrical in the original state, is also chucked in a lathe 24 and rotated around a first axis of rotation T1 here. However, it is also possible to use main bodies 22 having a different cross section, for example, elliptical or polygonal. Furthermore, a striking tool 26 is rotated around a second axis of rotation T2, which extends spaced apart by the distance D and in parallel to the first axis of rotation T1. The striking tool 26 comprises two fly cutters 30 in the illustrated example, which are fastened on a disk-shaped receptacle body 28 distributed uniformly over its circumference. The distance of the two axes of rotation T1, T2 is dimensioned so that the fly cutters 30 can engage within an engagement zone E in the main body 22.

(15) The main body 22 is rotated in a first rotational direction and the striking tool 26 is rotated in a second rotational direction. The rotational directions are identified by the arrows P3 and P4. With respect to FIG. 2, the main body 22 is rotated to the right and the striking tool 26 is rotated to the left. As with meshing gear wheels, the rotation in opposing directions has the result that the fly cutters 30 and the main body 22 primarily move in the same direction in the engagement zone E.

(16) In addition to the rotation around the second axis of rotation T2, the striking tool 26 is also moved along the second axis of rotation T2. Without the movement along the second axis of rotation T2, a concave cut-out 32, which has a width which approximately corresponds to the width of the fly cutter 30, will result as a consequence of the engagement of the fly cutters 30 in the main body 22. However, since the striking tool 26 is moreover moved along the second axis of rotation T2, a further cut-out 32 results upon each engagement, which is arranged offset in relation to the previously resulting cut-out 32 with respect to the first axis of rotation T1. The velocity at which the striking tool 26 is moved along the second axis of rotation T2 is selected in this case so that two adjacent cut-outs 32 merge into one another without interruption. As a consequence, a groove 34 results, which is formed by a plurality of cut-outs 32 merging into one another.

(17) The main body 22 is rotated at a first rotational velocity n1 and the striking tool 26 is rotated at a second rotational velocity n2. If the two rotational velocities n1, n2 are equal, two cut-outs 32 thus result on the main body 22, since the striking tool 26 comprises two fly cutters 30. Since the two fly cutters 30 enclose an angle of 180° with respect to the circumference of the receptacle body 28, the cut-outs 32 also enclose an angle of 180° in a plane extending perpendicularly to the first axis of rotation T1.

(18) If the two rotational velocities n1, n2 differ from one another, two adjacent cut-outs 32 are thus situated offset over the circumference of the main body 22. If the striking tool 26 is not moved along the second axis of rotation T2 in this case, a groove 34 results, which extends along the circumference of the main body 22 in a plane extending perpendicularly to the first axis of rotation T1.

(19) If the two rotational velocities n1, n2 differ from one another and if the striking tool 26 is moved along the second axis of rotation T2, a helical groove 34 thus results, approximately as shown in FIG. 2. However, to ensure an uninterrupted transition of two adjacent cut-outs 32, the velocity at which the striking tool 26 is moved along the second axis of rotation T2 cannot be excessively large. Moreover, the first and the second rotational velocity n1, n2 cannot differ excessively strongly from one another. A difference Δn in the rotational velocities n1, n2 of ±0.1% has proven to be advantageous, but can vary in dependence on the helix angle, feed rate per fly cutter, and length of the main body 22. With increasing difference Δn, the groove 34 has a stepped profile which becomes more and more strongly pronounced. In the case of an excessively large difference Δn, two adjacent cut-outs 32 are no longer connected to one another.

(20) FIG. 3 shows a second embodiment of the method according to the invention on the basis of a schematic illustration. In this exemplary embodiment, the striking tool 26 comprises a total of four fly cutters 30, which are arranged distributed uniformly over the circumference of the receptacle body 28. As already explained, the main body 22 and the striking tool 26 are rotated in different rotational directions. The fly cutters 30 comprise cutting faces 36, which are oriented in the exemplary embodiment shown in FIG. 3 so that they are moved forward during the rotation of the receptacle body 28. It is to be presumed hereafter that the first rotational velocity n1 and the second rotational velocity n2 are equal. In order that the fly cutters 30 can engage in a material-removing manner in the main body 22, the fly cutters 30 have to move forward with the cutting faces 36 thereof viewed in relation to the main body 22 within the engagement zone E. This is achieved in the exemplary embodiment shown in FIG. 3 in that the fly cutters 30 are arranged at a distance to the second axis of rotation T2 which is greater than the distance of the material in the engagement zone E to the first axis of rotation T1. The second tangential velocity vt2 of the fly cutter 30 is therefore greater than the first rotational velocity vt1 of the material of the main body 22 in the engagement zone E. FIG. 3 approximately indicates the ratios of the first tangential velocity vt1 of the material in the engagement zone E and the second tangential velocity vt2 of the fly cutters 30.

(21) FIG. 4 shows a third embodiment of the method according to the invention on the basis of a schematic illustration. The striking tool 26 again comprises four fly cutters 30, which are arranged in this case, however, so that the cutting faces 36 are moved in reverse, i.e., in the opposite direction, during the rotation of the striking tool 26. In order that the opposing rotational directions according to the invention of striking tool 26 and main body 22 again take place, the main body also has to be moved in reverse, i.e., in the opposite direction. This is important in the selection of the striking tool and the lathe, because there are counterclockwise and clock-wise striking tools, which differ in the arrangement of the blades. The striking tool which has to be selected is in turn dependent on where in the lathe the drive for the striking tool is seated and in which rotational direction one wishes to have the lathe run.

(22) In order that a material-removing engagement can nonetheless take place in the engagement zone E, the first rotational velocity n1 of the main body 22 has to be selected in relation to the second rotational velocity n2 so that the first tangential velocity vt1 of the material of the main body 22 in the engagement zone E is higher than the second tangential velocity vt2 of the cutting faces 36. The material is therefore moved toward the cutting faces 36 in the engagement zone E.

(23) The depth and the width of the cut-outs 32 and/or the grooves 34 can be set via the distance D of the two axes of rotation T1, T2 in relation to one another and via the diameter of the striking tool 26 and the main body 22.

(24) FIG. 5 shows a schematic illustration of a first exemplary embodiment of an electromagnetic actuator 38.sub.1 having a substantially cylindrical magnetic armature 40, which has been produced from an originally cylindrical main body 22 using the method according to the invention. The magnetic armature 40 is mounted in a guide unit 42, which is designed here as a guide tube, so it is movable along a longitudinal axis L. The magnetic armature 40 divides the guide unit 42 into a first section 44 and a second section 46, wherein the magnetic armature 40 comprises a first boundary surface 48, which faces toward the first section 44, and a second boundary surface 50, which faces toward the second section 46. In this case, the first boundary surface 48 is formed by a first end face 49 and the second boundary surface 50 is formed by a second end face 51 of the magnetic armature. The magnetic armature 40 is provided with a helical groove 34, which extends between the first boundary surface 48 and the second boundary surface 50. Depending on the area of application, the first section 44 and the second section 46 are filled with a gaseous or liquid fluid. In addition, the magnetic armature 40 comprises a receptacle 52, via which a push rod (not shown) can be fastened.

(25) Furthermore, the actuator 38.sub.1 comprises a pole core 54 and a coil unit 56, which can be energized. To move the magnetic armature 40, the coil unit 56 is energized, whereby the magnetic armature 40 moves along the longitudinal axis L toward the pole core 54 or away from it. It can be seen that the first section 44 is delimited by the first end face 49 of the magnetic armature 40, by the guide unit 42, and by the pole core 54. If the magnetic armature 40 is moved toward the pole core 54, the fluid would thus be compressed in the first section 44. If the magnetic armature 40 is moved away from the pole core 54, the fluid in the first section 44 would be expanded. In both cases, the mobility of the magnetic armature 40 would be restricted. However, since the magnetic armature 40 is provided with the groove 34 extending between the first and the second boundary surface 48, 50, a fluid equalization is ensured between the first and the second section 44, 46, so that the fluid in the first section 44 is not compressed or expanded during the movement of the magnetic armature 40. The mobility of the magnetic armature 40 is thus ensured.

(26) Because of the helical groove 34, the magnetic armature 40 is slightly rotated around the longitudinal axis L as it moves along it, whereby the wear of the magnetic armature 40 is distributed onto a larger surface. The operating time can be lengthened in this way.

(27) FIG. 6 shows a schematic illustration of a second exemplary embodiment of an electromagnetic actuator 38.sub.2, which substantially has the same construction as the actuator 38.sub.1 according to the first exemplary embodiment. However, the guide unit 42 is constructed differently. The guide unit 42 comprises a first plain bearing 58 and a second plain bearing 60. The first plain bearing 58 forms the first boundary surface 48, while the second plain bearing 60 forms the second boundary surface 50. The functionality of the actuator 38.sub.2 is the same as that of the actuator 38.sub.1 according to the first exemplary embodiment.

(28) FIG. 7 shows a perspective illustration of a keeper plate 62. The keeper plate 62 also comprises the cylindrical main body 22, which is formed disk-shaped here. A total of three of the cut-outs 32, which have been produced according to one of the above-described methods, are arranged originating from the lateral surfaces. In this case, the cut-outs 32 are each formed as a linear groove 34.

(29) FIG. 8 shows a third exemplary embodiment of an actuator 38.sub.3 on the basis of a sectional illustration. The actuator 38.sub.3 comprises, like the actuators 38.sub.1, 38.sub.2 according to the other exemplary embodiments as well, the coil unit 56, which is wound onto a coil carrier 64. Moreover, the actuator 38.sub.3 comprises the keeper plate 62 shown in FIG. 7, around which an injection-molded housing 66 made of plastic is overmolded. The housing 66 forms a plug receptacle 68 to supply the actuator 38.sub.3 with electrical energy and in particular to energize the coil unit 56.

(30) The approximate location of the gate 70 of the housing 66 is identified in FIG. 8. It can be seen that the gate 70 is located between the coil carrier 64 and the keeper plate 62. The cut-outs 32 ensure that the liquefied plastic can flow during the injection molding from the gate 70 into the sections of the housing 66 located behind the keeper plate 62 viewed from the coil carrier 64.

(31) Furthermore, it can be seen that the keeper plate 62 terminates flush with the housing 66 in the radial direction. In this way, the keeper plate 62 can be connected to electrical contacts and the magnetic field lines can be conducted optimally through the housing 66 to the coil unit 56.

(32) A push rod 72, also referred to as an axis, is shown on the basis of a perspective illustration in FIG. 9. The schematic construction of the push rod 72 is equivalent to that of the magnetic armature 40 shown in FIGS. 5 and 6, however, the push rod comprises a rod-shaped section 74, using which, for example, a valve body can be actuated. The push rod 72, like the magnetic armature 40 shown in FIG. 6, can be mounted so it is movable along the longitudinal axis L by means of plain bearings 58, 60 or by means of another bearing in the actuator 38. The push rod also comprises the first boundary surface 48 and the second boundary surface 50, which are formed as the first end face 49 and the second end face 51. In the illustrated exemplary embodiment, three cut-outs 32, which have been produced using the method according to the invention, extend between the first end face 49 and the second end face 51. In contrast to the magnetic armature 40, the cut-outs 32 do not extend in a helix, but rather extend linearly. The push rod 72 can be manufactured from a metallic material, for example, from a nonmagnetic stainless steel or brass. The push rod can also be manufactured from a magnetic material, however, the push rod 72 cannot be arranged in the magnetic circuit depending on the installation situation. In this case, a magnetic material could cause a magnetic short-circuit.

LIST OF REFERENCE SIGNS

(33) 10 main body 12 lathe 14 striking tool 16 receptacle body 18 fly cutter 20 cutting face 21 surface 22 main body 24 lathe 26 striking tool 28 receptacle body 30 fly cutter 32 cut-out 34 groove 36 cutting face 38, 38.sub.1-38.sub.3 actuator 40 magnetic armature 42 guide tube 44 first section 46 second section 48 first boundary surface 49 first end face 50 second boundary surface 51 second end face 52 receptacle 54 pole core 56 coil unit 58 first plain bearing 60 second plain bearing 62 keeper plate 64 coil carrier 66 housing 68 plug receptacle 70 gate 72 push rod 74 cylindrical section D distance E engagement zone L longitudinal axis n1 first rotational velocity n2 second rotational velocity Δn difference of the rotational velocities P arrow T1 first axis of rotation T2 second axis of rotation vt1 first tangential velocity vt2 second tangential velocity