AT500749A1 - SIGNALING MAGNETIC TRANSMISSION ELEMENT OF PLASTIC, TOOL FOR THE MANUFACTURE AND METHOD OF OPERATING THE TOOL - Google Patents

Description

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Sianalaebendes Maanetaetriebe element made of plastic. Tool for manufacturing and method of operation of the tool.

The invention relates to a tool for producing a signal-generating magnet-5 gear element and a method for operating this tool according to the preamble of patent claim 1.

Such transmission elements are usually formed of plastic and are used to determine the position of the position drive, for example in a 10 DVD Lautwerk, a car headlight readjustment and the like more actuators.

In such signal-generating transmission elements, which are usually formed of plastic, it was previously only known to mechanically press the magnetic ring used as a signal element 15 on the plastic part. There was the disadvantage that the connection was not strong enough to withstand certain load conditions. Particularly in the case of highly dynamic load changes, there was the danger that the magnet ring would strike or jam, which was associated with an inadmissible signal inaccuracy.

The mechanical pressing of the magnetic ring resulted, moreover, disadvantageously to an undesirable deformation of the ring, which led to a non-round barrel. This also affected the signaling. 25

Moreover, it has hitherto only been possible to press such magnet rings out of a sintered material, since magnetic rings made of a plastic-ferrite material can not withstand the high forces during pressing. They break. Incidentally, in order to avoid breakage of these plastoferror rings, it has been known to provide an even greater radial clearance between the press-fit and the *.

Magnet ring to ensure that the Plastoferritring was only slightly mechanically stressed.

This, however, undesirably impaired the concentricity, 5 because due to the higher radial clearance there was a risk that the pressed-on ring would succeed eccentrically and in turn distort the signal output.

This resulted in a corresponding signal inaccuracy or incurred corresponding signal failures, which in turn burdened the entire actuator 10 adversely.

The invention is based on the object, a signaling magnetic transmission element made of plastic, as well as a tool for producing the same in such a way that the signaling magnetic ring can be attached to the plastic part with substantially improved 15 concentricity and under stress least destructive forces.

To solve the problem, the invention is characterized by the technical teaching of claim 1 and the other independent claims. 20

The signal is read out via so-called Hall elements, which are arranged in the form of an electronic component on a printed circuit board and must be arranged in a very accurate, small distance from the rotary signal generator. In accordance with the invention, a plastoferrite is produced by injection molding, for example, based on PA12 with strontium and / or barium ferrite with, for example, 9 pool saves, ie 18 signal changes per revolution, and a multiple-speed, for example 2- or 4-screw, screw made of, for example, polyacetal or other comparable technical thermoplastic 30 plastics integrally formed. • * * * * * * · «« ···· ** * * * *· * * * 4 * * *

The plastoferrite ring can already receive a magnetic alignment in the tool, but preferably a subsequent magnetic alignment is brought about. The sprue of this injection molded part is made by means of a so-called Schirmangusses with extremely fine Angußabmessungen and the 5 punched is integrated into the injection mold. A radial clearance of less than or equal to 0.04 mm or less than or equal to 0.02 mm eccentricity is sought and is required for proper function.

The Plastoferrit is fixed in a Einlegespritzgusswerkzeug means of special 10 actuators so that during the injection molding process, for example, polyacetal for the production of the screw no expansion and / or Aussermittigkeit and / or no runout occurs, which would adversely affect the signaling effect to Hall element. In particular, various injection molding phases were developed in this manufacturing process and care was taken to exert the least possible radial pressure on the plastoferrite ring. In addition, attention must be paid to a complete injection of the screw and in the area of the plastoferrite ring attention is paid to ventilation or to a good connection 20, since the radial accelerations and their frequency in the normal operation of a DVD drive are considerable.

In the area of the plastoferrite ring, the thermoplastically produced screw has a bore for receiving the motor shaft and in this case pressure forces 25 of, for example, greater than or equal to 30 n and less than or equal to 90 N are specified.

The thermoplastic screw generally has a multi-start spiral thread and it is according to the invention a 4-course 30 spiral with a maximum 13.76 ° slope (0.3 module) as just produced • ♦ recognized because there is otherwise an undercut in the tool and thus demoulding would no longer be possible.

In a further embodiment of the present invention, the plastoferrite ring and the thermoplastic worm element are produced by means of a so-called twin-screw injection molding process, and according to the invention the plastoferrit ring is first produced here.

In a further development, this two-part injection-molded element is replaced by a one-piece element and therefore the entire highly dynamic signaling coupling element is made of plastoferrit. It must be made the configuration such that only an outer ring can be magnetized and causes a sufficient signal generator effect in conjunction with a Hall element. The property of the Plastoferrites are here in terms of 15 matched to the mechanical properties and requirements of a worm drive.

In summary, it is stated that one of the essential features of the invention is that the signaling magnetic transmission element now consists of a 20 magnet ring made of a Plastoferritmaterial and that the Plastoferritring is injection molded in the injection-plastic injection molding process to the plastic injection molding.

In a further development of the present invention, it is provided that the plastofoelriting ring is protected against destruction in a special way in the tool mold. This is inventively achieved in that in the mold insert of the mold a receiving groove for the deposit of Plastoferritringes is created, in which the Plastoferritring is inserted prior to the production of the plastic injection molding. 30 · · · · · · · · · · · · · · · · · · · · · ·

In order to protect this plastic ferrite ring, which is very sensitive to radial explosive forces, it is provided in a first step according to the method that radial, circumferentially distributed supporting elements are arranged on the receiving groove for receiving the plastoferrite ring, which has a radial play of e.g. Allow 0.01 to 5 0.02 mm. Due to the arrangement of the radial support elements on

Outer circumference of the Plastoferrit ring results in the said radial clearance and it follows that the ring is first claimed with no radially directed forces. These support elements are used only for centering the Plastoferritringes in the receiving groove of the mold, without the ring 10 is attacked even load transfer.

The radially outward play between the inner circumference of the support elements and the outer periphery of the Plastoferritringes is chosen so that in the injection molding process, in which the ring due to the centrally flowing 15 plastic mass radially directed outwardly widens, this now applies to the inner sides of the support elements However, the contact forces are so small that a collapse of the ring is prevented in any case.

To solve the task of avoiding a rupture of the ring, not only serve 20 the specified radial support elements, which cause only a pre-centering, but beyond even directly on the shell circumference of the ring deliverable position elements.

These are also directed in the radial direction, uniformly distributed on the circumference 25 and complement each other with the likewise radially arranged support elements, so that all elements (support elements and control elements) approximately close to the outer periphery of the Plastoferritringes include and support. • ·· · t 1 · · · · · * ·· *! ··· »

However, the latter actuating elements lie without radial play directly on the outer circumference of the ring. It may even be set in a radially inwardly directed biasing force. 5 According to a development of the invention, the adjusting elements are uniformly driven undeliverable by a circularly driven adjusting ring in the radial direction. The collar drives all control elements synchronously. Thus, they are delivered with uniform force on the jacket of the ring and compensate for the injection pressure, which is directed radially outward from the central region of the mold tool 10 and tries to blow up the Plastoferritring.

It is thus created with the adjusting elements adjustable depending on the injection pressure force-transmitting sleeve on the outer circumference of the Plastoferritringes and this is thereby secured against breakage. 15

Of course, each actuator is initially radially deliverable separately to allow basic adjustment. If this absolutely necessary basic adjustment has been carried out, then all the adjusting elements can be driven uniformly inward and outward in the radial direction by the aforesaid rotary-driven adjusting ring.

The synchronous contact with the outer circumference of the Plastoferritringes before introduction of the injection molding compound, so that even before the initiation of the plastic mass of Plastoferritring is supported load-transmitting on its entire outer circumference.

In a further development of the invention, however, it may additionally be provided that the adjusting elements are adjusted in their radial feed drive in the direction of the jacket of the Plastoferritringes depending on the injection pressure or 30 certain cycle times during injection molding.

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It is important that these adjusting elements can also be adjusted radially outward for the purpose of removal of the Plastoferritringes after completion of the plastic injection molding, so as to get the receiving cavity free again and to be able to demold the finished gear element. 5

Important in the invention is therefore that for pre-centering of the Plastoferritringes in the receiving relatively relatively rigid support elements are arranged, which result in a radial clearance to the arranged in the interior Plastoferritring. 1 o It is also important that evenly distributed further control elements are present, but create the load-bearing on the outer circumference of the Plastoferritringes and supported against the injection pressure.

In the following the invention will be explained in more detail with reference to drawings showing only one embodiment 15. Here are from the drawings and their description further features essential to the invention and advantages of the invention.

Show: 20

1 shows a transmission element according to the invention in perspective side view,

FIG. 2: the gear element according to FIG. 1 in another embodiment, 25

FIG. 3: top view of the magnetic ring,

FIG. 4: section through the magnetic ring in FIGS. 3, 30

FIG. 5: longitudinal section through the transmission element according to FIG. 1,

FIG. 6: top view of the mold insert with adjusting ring,

Figure 7: section through the right side of the mold, namely the nozzle side. In FIGS. 1 to 5, a plastic transmission element 1 is generally shown, which consists essentially of a shaft 2 which carries a toothing 3. The toothing can be designed as spiral toothing, involute toothing or else as straight toothing according to FIG. 10

The shaft 2 is materially integral with a likewise made of plastic head 4, in the region of said magnetic ring is embedded. The magnetic ring is referred to in the following description as Plastoferritring 5, although it could also be made of other materials 15. The material specification Plastoferrit is therefore not to be understood as limiting the right of protection.

This means that if you have a magnetic ring made of another material, e.g. a sintered material, the same advantages would be achieved according to the invention.

Even with this very brittle sintered material, the advantages of the invention are achieved, namely the non-destructive spraying of such a ring 5 to the plastic body of the transmission element 1. 25th

The transmission element 1 has, moreover, a central axis of rotation 6, and, moreover, in the head region consists of a lower conical projection 7, which merges beyond the ring 5 into an also conical projection 9. In the area of the top surface and the projection 9 radially directed webs 8 are arranged, the 30 as Anspritzkanal and as injection point for the production of

Plastic injection serve and stabilize the rest of the head 4 mechanically.

FIG. 2 shows that such an injection point 12 is arranged radially outward at the end face of a web 8. However, the invention is not limited thereto. The injection point 12 could also be arranged, for example, in the region of the shaft 2, in particular in its end face.

In the head region of the head 4, the webs form an upper cover surface 10, which is penetrated by a central bore 11, which passes through the entire plastic body, as can be seen from FIG.

FIG. 3 shows such a plastoferror ring in plan view, and it can be seen that recesses 13 which are distributed uniformly around the circumference are present, which serve for anchoring in the plastic material of the plastic injection molding.

Incidentally, it has a central bore 15, and the embedding of this ring 5 in the plastic material is shown in more detail in FIG.

Here it can be seen that in the head area a receiving space 16 is formed, and in the receiving space 16 now the recesses 13 engage, so that the

Plastic material engages during the injection molding in these recesses 13 and the ring 5 toothed in the plastic material. It is thus interlocked against radial and against forces directed in the circumferential direction. 25 The ring flange 14 of the magnetic ring is thus embedded in a particularly load-transmitting manner in the plastic body of the transmission element 1.

In Figure 6, the top view of a mold 17 is now shown on the nozzle side. This mold is shown in Figure 7 still in section. 30

A central cavity is formed in the mold 17, which essentially consists of the central core bore for a core pin 22. From this central core bore extends radially outwardly a cone groove 20, by means of which the previously described projection 9 in the head 4 of the transmission element 5 1 is formed.

Radially outward from this conical groove 20, the receiving groove 18 extends for receiving the magnetic ring 5. From the cone groove 20, extending channels or slots 19, which serve for forming the webs 8 shown in Figure 2 10 on the head 4 of the transmission element 1 ,

At one of the webs opens a runner 21, which is arranged in the region of a support member 23 and over which the plastic material flows into the head area. 15

It is important that in the area of this mold insert 31 a plurality of evenly distributed circumferentially arranged support members 23 are present. In the exemplary embodiment shown, these are three support elements 23, which are directed in the direction of the central mold cavity. 20

It is also possible to use more or less than three support elements 23. It is important that the front end of the support elements 23 - which are directed next to the lateral surface to the ring 5 - form a radial clearance 25 in the direction of the receiving groove 18. In this receiving groove 18 of the magnetic ring 5 is inserted. 25

After inserting the magnet ring 5 in the receiving groove 18 now an outer - rotationally driven in the circumferential direction - collar 28 is set in motion.

The adjusting ring 28 has in each case inwardly directed parking ramps 29, which are formed inclined in the circumferential direction. These adjustment ramps 29 are made of a highly wear-resistant steel and form sliding surfaces for rolling bearings 42, which are arranged at the radially outer ends of adjusting elements 26. These adjusting elements 26 are held radially displaceable and lockable in respective setting scenes 27. With the rotary drive of the adjusting ring 28, therefore, the rolling bearings 42 slide on the inclined adjusting ramps 29 and thus, for example, 5 radially inwardly displaced in the direction of arrow 24. Thus, the radially inwardly directed ends of the adjusting elements 26 engage in a load-transmitting manner on the outer circumference of the magnetic ring 5. The adjustment is exactly synchronous, i. the forces with which the respective actuating element 26 rest against the ring are exactly dimensioned by a presetting of the respective actuating element in such a way that all the actuating elements engage the outer circumference of the magnetic ring with relatively equal force.

The bearing of the adjusting ring 28 in this case takes place in housing-fixed outer guide elements 34 which are arranged on the mold plate. 15

There are also shown fastening screws 41, which show a guide cover for the mounting of the adjusting ring 28.

7 shows a section through the nozzle-side half of the mold 20 32. It consists essentially of a mold plate 33, with the mold insert 31st

There is a Ausspritzdüse 38 which ejects into a directed against the mold parting plane 40 nozzle orifice 37. It is important that the plastic material from the nozzle orifice 37 enters the opposite half of the mold (not shown in the drawing), where it is guided into a diversion channel, and the diversion channel again opens into the injection tunnel 39 arranged on the mold plate 33.

The plastic material is thus injected from the Anspritzdüse 38 first in the opposite mold half, and then back to turn back and 30 in the Anspritztunnel 39 of the mold plate 33.

This is considered to be particularly advantageous because it does not require space consumption in the area of the adjusting elements according to FIG.

The injection tunnel 39 opens into the injection point 12, which is shown in FIG.

In the area of the central axis 35, a bore core pin 36 is arranged, which centers the right-hand forming tool 32 with the left-hand molding tool (not shown in the drawing). 10

From Figure 7 it can be seen that the adjusting elements 26 are displaced approximately flush with the mold parting plane.

It can be seen that the front ends at least partially comprise the outer circumference of the 15 magnet ring, wherein one perimeter of each control element of e.g. 30 ° is present and all three adjusting elements then give a surrounding area of 90 °, while the rest of the surrounding area is effected by the enclosure by means of the support elements 23. 20 The magnet ring 5 is therefore essentially encompassed over its entire jacket area by the support elements 23 and the adjusting elements 26 directed towards it.

Advantage of the mold is so that now very sensitive to injection molding magnetic rings can be molded onto a plastic part, 25 without causing damage to this magnetic part. The production takes place in a single shot, because yes with the injection molding of the transmission element 1 and with the insertion of the magnetic ring 5 in the mold, the entire plastic molded part is produced in one operation. This is a significant labor savings compared to the aforementioned 30 mechanical mounts between magnet ring and plastic injection molding.

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Drawing legend 1 Gear element 22 Core pin 2 Shaft 25 23 Support element 5 3 Gearing 24 Direction of arrow 4 Head 25 Radial clearance 5 Plastoferrit ring 26 Adjustment element 6 Axle 27 Adjustment gate 7 Conical shoulder 30 28 Adjustment ring 10 8 Struts 29 Stellrampe 9 Ansatz 30 Pfeilrichtung 10 Deckfläche 31 Mold insert 11 Center hole 32 Molding tool (nozzle side) 12 Injection point 35 33 Molding plate 15 13 Recess 34 External guide element 14 Ring flange 35 Axis 15 Center bore 36 Drill core pin 16 Receptacle 37 Nozzle mouth 17 Mold 40 38 Injection nozzle 20 18 Receptacle (for 5) 39 Injection tunnel 19 Slot (for 8) 40 Mold parting plane 20 Cone groove (for 7) 41 Fixing screw 21 Gating channel (for 12 = 42 rolling bearings

Claims (16)

1. Signaling magnetic gear element made of plastic with a toothing bearing shaft (2) and acting as a signal element 5 magnetic ring which is non-positively connected to the shaft (2), characterized in that the magnetic ring as a plastoferrite ring (5) injection molding technology to the shaft (2) is formed. 2. Magnetic gear element according to claim 1, characterized in that 10 of the shank (2) is designed as a thermoplastically produced screw, the eim single or multi-start spiral thread, z. B. are also 1-2-3-4 common thread possible, but this is the max. Slope each smaller than 4-speed spiral with a maximum of 13.76 ° slope (0.3 module) has. 3. Magnetic gear element according to claim 1 or 2, characterized in that both the shaft (2) and the plastoferrite ring (5) are made of the same magnetically activatable material. 4. Tool for producing a signaling magnetic transmission element 20 made of plastic, characterized in that a plastoferrite ring (5) to the thermoplastic material of the shaft (2) is integrally formed. 5. Tool according to • V • · ♦ · ♦ ♦ · ··· * ··· • ♦ • ♦ • ♦ • t. 7. Tool according to one of claims 1 to 6, characterized in that the sprue of the injection molded part takes place by means of a so-called Schirmangusses. 8. Tool according to one of claims 1 to 7, characterized in that the plastoferrite ring (5) is fixed in the Einlegespritzgusswerkzeug by means of special adjusting elements so that the injection molding process for the production of the worm no widening and / or Aussermittigkeit and / or no Radiation occurs. 10 9. Tool according to one of claims 1 to 8, characterized in that on the receiving groove, in which the Plastoferrit ring is inserted, supporting elements are arranged, which on the outer circumference of the receiving groove a radial play of e.g. 0.01 to 0.02 mm to the inserted plastoferrite ring (5) result. 15 10. Tool according to one of claims 1 to 9, characterized in that create control elements directly on the outer circumference of the Plastoferrit ring (5) ring 11. Tool according to claim 10, characterized in that the adjusting elements exert a radially inwardly directed biasing force on the Plastoferrit ring (5). 12. Tool according to one of claims 9 to 11, characterized in that the adjusting elements are uniformly driven by a circularly driven adjusting ring in the radial direction deliverable. 13. Tool according to one of claims 9 to 12, characterized in that an adjustable depending on the injection pressure force-transmitting sleeve is applied to the outer periphery 30 of the Plastoferritringes and this is thereby secured against breakage. 14. A method of operating a tool according to one of claims 1 to 12, characterized in that the plastoferrite ring (5) and the thermoplastic worm element is produced by means of a twin-screw injection molding process and in this case the plastoferrite ring is first produced. 5 15. A method of operating a tool according to one of claims 1 to 12, characterized in that the plastoferrite ring (5) and the thermoplastic worm element are produced in a single injection molding process from the same material. 10 16. A method for operating a tool according to one of claims 1 to 12, characterized in that the plastoferrite ring (5) is injection-molded in the injection-plastic injection molding process to the plastic injection molding. 17. A method for operating a tool according to one of claims 1 to 15, characterized in that the radial feed drive of the adjusting elements is adjusted in the direction of the jacket of the Plastoferritringes depending on the injection pressure or of certain sequences during injection molding