DE102004051003A1 - Plastic covered pulley, in particular belt pulley for air conditioning compressor, has injection molded and heat cross-linked thermosetting plastic pulley body around outer bearing ring - Google Patents

Abstract

The pulley rotates on an anti-friction bearing(3) comprising an inner bearing ring(3.1) and an outer bearing ring(3.2). A pulley body(2) of thermosetting plastic is injection molded as a single component around the outer bearing ring. Complete cross-linking of the thermosetting plastic is realized by heating. A twin row ball bearing forms the low friction bearing unit(3). Bearing balls(3.5,3.6) and the bearing inner ring(3.1) are selected to match the measured track dimensions of the outer ring(3.2). When assembled the total radial play of the ball bearing assembly is 5-15 microns and between both rows of balls the difference in radial play >=6 microns. An independent claim is included for a process for manufacturing a plastic covered pulley in which: a) a pulley body(2) is injection molded around the outside of the outer bearing ring(3.2); b) the injected plastic is heat treated at 200[deg]C; c) the track of the outer ring and the inner ring are measured and bearing balls(3.5,3.6) are selected to suit; d) the pulley is assembled from the various components.

Description

field of use the invention

The The invention relates to a plastic-coated roll, in particular a belt pulley in an air conditioning compressor, comprising one of a Bearing inner ring and a bearing outer ring consisting of rolling bearings, the bearing outer ring from a reel body is encapsulated from a polymeric material.

background the invention

Plastic-coated Roles of o. G. Art that dampen vibration and noise, are already are well known and are used, for example, as deflection or tensioning rollers in aggregates such as generator, air conditioning compressor or water pump in Internal combustion engines used. In many cases have internal combustion engines about that In addition, another traction drive for driving the camshaft on, these traction drives designed with a toothed belt Traction means are provided. Due to the functionally offset Arrangement of individual units on the internal combustion engine is the Zugmittelbetrieb provided with pulleys, the sufficient wrap angle Ensure at the belt pulleys of the aggregates.

A generically trained plastic-coated roll in the form of a tension roller is, for example, from the DE 32 40 075 A1 out. It consists of a double-row sealed to both sides deep groove ball bearings, the inner ring can be fixed by means of a fastening screw to a connecting structure. The outer ring is enclosed by a roller body made of a polymeric material, wherein the roller body seen in longitudinal section is formed double-T-shaped. Other plastic-coated rollers are exemplary in the DE 35 03 311 A1 . DE 36 25 800 A1 . DE 41 26 938 C3 . DE 44 99 780 C1 . DE 102 20 690 A1 . DE 199 37 681 C2 and in the DE 197 02 180 A1 described above.

After in the DE 25 29 913 C2 described procedure for producing such a plastic-coated roll, this is done such that the existing inner ring, outer ring and rolling element bearings is placed in an injection mold and molded there for the purpose of applying the sheath with plastic.

• – Es ist keine komplette Vernetzung des Kunststoffes möglich, die aber für die Maßstabilität und die Belastung der Rolle von entscheidender Bedeutung ist. Die Vernetzung beginnt mit der Umspritzphase, ist aber danach nicht abgeschlossen und vollendet sich unvollständig bei Betrieb der Rolle, so dass die Kunstoffummantelung erstens nicht maßstabil und zweitens auch nicht größeren Belastungen aussetzbar ist.
• – Ein weiterer Nachteil liegt darin, dass durch die Abkühlung nach dem Umspritzen der Außenring eingeschnürt wird und so das Radialspiel des Wälzlagers in nicht gewünschter Weise beeinflusst wird.

The overmolding of the overall bearing, which is completed after about one minute, however, has the following disadvantages:

• - It is not possible a complete networking of the plastic, but for the dimensional stability and the load of the role is crucial. The cross-linking begins with the overmolding phase, but is then not completed and completes incomplete in the operation of the role, so that the Kunstoffummantelung firstly not dimensionally stable and secondly not be exposed to greater loads.
• - Another disadvantage is that is constricted by the cooling after encapsulation of the outer ring and so the radial clearance of the bearing is not influenced in an undesirable manner.

Would you now a complete one To seek networking, it would have to the plastic is kept at 200 ° C for a considerable time. this in turn would mean, that all Bearing components, such as bearing outer ring, Bearing inner ring, cage, Seal and lubricant also designed for this temperature would have to even if the later Use temperature of the roll is substantially below 200 ° C. Specifically, this means that both the bearing inner ring and the bearing outer ring a so-called stabilization would have to be subjected. among them is in accordance with the INA factory standard N 030 050 a heat treatment To understand, so that these parts permanently at high temperatures can be operated. This stabilization is required because at high temperatures a partial structural transformation in the material, associated with dimensional changes occur can. According to the mentioned INA factory standard would have therefore inner and outer ring for the permanent Use at 200 ° C (Stabilization level S1) dimensionally stabilized be, but this is expensive and expensive. On top of that, at a complete network the plastic is also to use sealing material that is in This temperature range retains its original characteristics. The same applies for to be used lubricant, which is in the temperature range of 200 ° C not may decompose.

To The prior art thus requires either a complete Networking of the plastic with a complex adaptation of all Stock components to buy at the specified temperature range or on a full Dispense networking of the plastic.

Summary the invention

outgoing from the disadvantages of the known prior art is the invention Therefore, the object of the invention to provide a generic role, the on the one hand a complete has crosslinked plastic, but on the other hand inexpensive to produce is.

According to the invention this Task according to the characterizing part of claim 1 in conjunction with the preamble solved by the fact that the reel body a thermoset consists and the bearing outer ring as an item overmoulded and to the full Thermoset crosslinking of the thermoset is.

As the expert knows Duroplast is the generic term for a group of usually hard, amorphous and decomposition temperatures rigid plastics that come from spatially closely meshed macromolecules are built up and therefore high have mechanical strength. They set at low temperatures steel elastic substances that do not even at high temperatures flowing viscously, but between 50 ° C or a higher one Temperature and the decomposition temperature with very limited deformability behave elastically.

Under Networking is the formation of intermolecular bridges between linear macromolecules with reactive Places forming a three-dimensional network by addition of crosslinking agents. The networking causes a increase the hardness and the toughness of the original Stoffes, also called hardening referred to as.

One The advantage of the separate treatment of the bearing outer ring is that a complete network of the thermoset is achieved. On the one hand, this guarantees high dimensional stability, what kind of the role of the whole role is important and the other becomes the load capacity the role significantly improved. This is especially for refrigerant compressors in motor vehicles of importance, since there a high torque at a high operating temperature is transmitted.

One Another advantage of the separate treatment of the bearing outer ring is that the usual Bearing components such as bearing inner ring, cage material, sealing material and lubricants need not be sized so that they also loads of 200 ° C have to endure. Related to the already mentioned Norm N 030 050 means that that the bearing inner ring only hinsichtlicht a limit temperature of 150 ° C must be stabilized (S0). For cage material, Sealing material and lubricant also means a reduction in costs, since these only up to 150 ° C be consistent have to.

At long last is the invention of the contradiction of the prior art the technique of accepting an incomplete networking of the Plastic at low cost other bearing components or in a complete cross-linking of the plastic and costly other parts of the warehouse are dissolved. With In other words, the plastic-wrapped roll has a fully cross-linked roller body on and the rest Bearing components are also inexpensive.

advantageous Embodiments of the roller according to the invention are in the subclaims 2, 3 and 4 described.

So is provided according to claim 2, that the rolling bearing as a double row Ball bearing is formed. From claim 3 it is apparent that the Bearing balls and the bearing inner ring of the bearing ball bearing accordingly a measured career of the encapsulated bearing outer ring are sorted bearing components. From claim 4 shows that the ball bearing has a total radial clearance of 5 - 15 microns, wherein between the two ball rows a radial play difference of ≤ 6 microns set is.

By the separate treatment of the bearing outer ring with subsequent measurement of his Career and the sorting of suitable rolling elements and matching bearing inner ring can be in a simple way to the radial clearance of the plastic coated Role act. The built-in roll should allow it to be flawless running, one possible to have a small game. this leads to to an improvement of the bearing function and thus to an improved reliability and an increased efficiency an associated unit, such as an air conditioning compressor.

• – Umspritzen des Lageraußenringes
• – Wärmebehandlung des umspritzen Lageraußenringes
• – Vermessen der Laufbahnen des Lageraußenringes, der Laufbahnen des Lagerinnenringes und Zusortierung der zugehörigen Lagerkugeln
• – Montage der Rolle aus den einzelnen Bestandteilen

The associated method for producing a plastic-coated roll according to the invention is characterized by the following method steps:

• - Injection of the bearing outer ring
• - Heat treatment of the encapsulating bearing outer ring
• - Measuring the raceways of the bearing outer ring, the raceways of the bearing inner ring and sorting of the associated bearing balls
• - Assembly of the roll from the individual components

Finally is according to one Last feature of the method according to claim 6 provided that the heat treatment to crosslink the plastic at about 200 ° C.

The Invention will be explained in more detail in the following embodiment.

Short description the drawings

It demonstrate:

1 a longitudinal section through a bearing outer ring with a sprayed-on roller body and

2 a longitudinal section through a complete bearing with sprayed-on roller body.

Full Description of the drawings

As can be seen from the two figures, the with 1 designated plastic coated roll from the reel body 2 , which consists of a thermoset, and the rolling bearing in the form of a deep groove ball bearing 3 , This consists of the bearing inner ring 3.1 , the bearing outer ring 3.2 , between those on associated, undesignated raceways in cages 3.3 . 3.4 guided bearing balls 3.5 . 3.6 roll. The deep groove ball bearing 3 is on both sides out through the seals 3.7 . 3.8 protected. As can be further seen, the reel body encloses 2 with his hub 2.1 and its radially inwardly directed flange 2.1 .1 the lateral surface of the bearing outer ring 3.2 and its left-side end face. The reel body 2 encloses with its hollow cylindrical barrel casing 2.2 the hub 2.1 wherein both parts pass through the radially extending disk 2.3 are connected with each other.

The production of the roll according to the invention takes place as follows:
First, the bearing outer ring 3.2 of the radial bearing 3 according to the standard N 030 050 subjected to stabilization. This is necessary in order to survive the subsequent cross-linking temperature of the thermoset in the amount of 200 ° C without damage. Subsequently, the bearing outer ring 3.2 spent in an injection mold and there for the purpose of applying the roller body 2 molded. Thereafter, the encapsulated bearing outer ring 3.2 held for several hours in a suitable unit at a temperature of 200 ° C. This is done until the crosslinking of the reel body 2 is completed and this receives a high dimensional accuracy and a high load limit.

In a next process step, both the raceways of the bearing inner ring 3.1 as well as the raceways of the bearing outer ring 3.2 like the bearing balls 3.5 . 3.6 measured and sorted according to each other. This has the purpose of giving a given radial clearance, which is responsible for the function and smoothness of the ball bearing 3 is essential, is adjustable in a simple manner. The sorting of bearing inner ring 3.1 , Bearing outer ring 3.2 and bearing balls 3.5 . 3.6 should be done so that the ball bearing has a total radial play in the range of 5 - 15 microns, with between the two rows of balls 3.5 . 3.6 a radial clearance difference of ≤ 6 microns should be present. Subsequently, the two bearing rings 3.1 . 3.2 pushed into each other, and the bearing balls 3.5 . 3.6 be right or left between the races 3.1 . 3.2 introduced. After that, there may be an introduction of the two cages 3.3 . 3.4 connect before greasing the bearing 3 takes place and finally on both sides of the sealing rings 3.7 . 3.8 be used.

1

plastic-coated role

2

roller body

2.1

hub

2.1.1

flange

2.2

Counterweight

2.3

disc

3

Deep groove ball bearings

3.1

Bearing inner ring

3.2

Bearing outer ring

3.3

Cage

3.4

Cage

3.5

bearing ball

3.6

bearing ball

3.7

poetry

3.8

poetry

Claims (6)

Plastic coated roll ( 1 ), in particular a belt pulley in an air conditioning compressor, comprising a bearing inner ring ( 3.1 ) and a bearing outer ring ( 3.2 ) existing rolling bearings ( 3 ), wherein the bearing outer ring ( 3.2 ) of a roller body ( 2 ) is encapsulated from a polymeric material, characterized in that the roller body ( 2 ) consists of a thermoset and the bearing outer ring ( 3.2 ) is overmolded as an item and heat treated to fully crosslink the thermoset. Plastic coated roll ( 1 ) according to claim 1, characterized in that the rolling bearing ( 3 ) is designed as a double-row ball bearing. Plastic coated roll ( 1 ) according to claim 1, characterized in that bearing balls ( 3.5 . 3.6 ) and the bearing inner ring ( 3.1 ) of the ball bearing ( 3 ) corresponding to a measured track of the encapsulated bearing outer ring ( 3.2 ) are sorted bearing components. Plastic coated roll ( 1 ) according to claim 1, characterized in that the ball bearing ( 3 ) has a total radial play of 5 to 15 microns, wherein between the two rows of balls ( 3.5 . 3.6 ) a radial clearance difference of less than or equal to 6 microns is set. Method for producing a plastic-coated roll ( 1 ) according to claims 1, 2, 3 and 4, characterized by the following method steps: - encapsulation of the bearing outer ring ( 3.2 ) - Heat treatment of the encapsulated bearing outer ring ( 3.2 ) - Measuring the raceways of the bearing outer ring ( 3.2 ), the raceways of the bearing inner ring ( 3.1 ) and sorting of the associated bearing balls ( 3.5 . 3.6 ) - Assembly of the roll ( 1 ) from the individual components Method according to claim 5, characterized in that that the heat treatment at 200 ° C he follows.