HK1151572A - Method for fixing a bearing ring on or in a component - Google Patents

Description

Method for fixing a bearing ring on or in a component

The invention relates to a method for fixing a bearing ring on or in a component by means of adhesive bonding.

In each case, for example when long bearing shafts are used, the free positioning and secure fit of the bearing on the component to be supported is of considerable importance when assembling the rolling bearing. Of course, the economic cost for achieving such positioning plays a significant role.

For such fixation, mechanical solutions are known and commonly used. Here, clamping sleeves are used which establish a friction-fit connection by conical fitting. Furthermore, eccentric rings are known with which a fixed connection between the bearing and the component to be supported can be established. Bolted connections are also commonly used. In this case, headless screws which are screwed into the connecting part radially with respect to the shaft are used in particular to fix the bearing on the shaft-like part.

Furthermore, the fastening by means of a clamping sleeve has the disadvantage that at least three components are required for the fastening. They must have a relatively high degree of precision, which entails a corresponding expense. In addition to the manufacturing and cost expenditure, the multiple components also mean a build-up of manufacturing tolerances. These tolerances may disadvantageously accumulate depending on the actual dimensions.

A further problem in the assembly of the clamping sleeve is that the cross section of the sleeve must be selected so large for strength reasons that, in addition to the combined clamping sleeve (special sleeve), a further larger number of bearing characteristics must be selected in order not to weaken the bearing ring too much on the other side. This fact limits the structural gap. In connection therewith, there is also the case that a recess must be provided for the sealing element (for example an O-ring) in any case in order to place the sealing element therein, which recess however causes weakening of the respective component.

Therefore, changing from headless screw fixation to fastening sleeve fixation, for example, also requires adjustment of the installation space. This means that, in the case of an increase in the power (e.g. rotational speed) of a machine, which requires just a higher operating accuracy, the application can no longer be designed so compactly.

A particular problem in the use of clamping sleeves is that it is only difficult to define the desired position of the bearing by pushing during assembly. In practice, this means that the press connection must be canceled again in order to be able to perform a new positioning; optionally, design measures have to be taken, for example the creation of a special assembly device. The positioning of the bearing just fixed does not allow deviations from a given position, since otherwise the position of the shaft relative to the surrounding structure may limit the function.

When using screw connections and eccentric rings, the problem arises that with this possible fixing solution, the bearing ring can tip over into the shaft-shaped part. This results in a standstill of the operation or a reduction in the accuracy of the operation.

Furthermore, there is the problem that the fastening, depending on the load, may not be sufficient to completely avoid micromotion. Fretting corrosion, which leads to corresponding collateral damage, is often observed in the mating seams of such bearings. If the fixation is tightened so strongly, the fixation (in particular the headless screw) may be damaged.

In view of the strength of the fixation of the bearing ring on the component, it is disadvantageous that the transmission of axial forces may be significantly limited. In the first place, when headless screws are used, the deformation of the bearing ring can also occur as a result of too strong tightening of the screws, which leads to disadvantageous operating characteristics and clamping. This must be compensated by a correspondingly large bearing play. However, the increased bearing play has the disadvantage of an unfavorable load ratio in the bearing. Otherwise, it is also possible to influence the radial bearing play by the assembly. Depending on the kind of bearing (e.g. especially in deep groove ball bearings), it may be difficult to control the amount of reduction of the bearing clearance. This can result in radial clamping of the bearing. This requires complex monitoring of the assembly or a bearing structure with a reduced service life.

Furthermore, it is disadvantageous that the headless screw achieves its strength by being shoveled into the material of the component (shaft), i.e. by a form-fitting connection. It is difficult to disassemble the bearing since this results in build-up on the shaft.

A particular problem with eccentric rings is that a fixed connection can only be achieved by twisting the two rings relative to each other. However, this means that vibrations of the fitting seam occur during rapid changes in the bearing rotational direction and the connection can thus be released.

It is also known to design an adhesive bond for fixing the bearing on or in the component. Such a solution is described, for example, in DE 2203664 a 1. The adhesive is introduced directly between the parts to be joined when the fitting seam is inserted. A disadvantage of this method is that the difficulty of introducing adhesive into the assembly line or the reliability of the process-especially in view of the amount of adhesive to be delivered and the neatness of the joined parts-is linked to the situation at the time of assembly or to the individual assembly workers.

Furthermore, the aforementioned solutions have the disadvantage that surrounding components, for example seals, can be wetted with adhesive when the adhesive is introduced manually. The function of such components may be adversely affected.

The object of the invention is to improve a method for fixing a bearing ring to or in a component by means of adhesive bonding in order to avoid the above-mentioned disadvantages. In particular, a clean adhesive bond which acts only at the desired location and which establishes a reliable connection between the bearing ring and the component is achieved in a simple and inexpensive manner.

The method of the invention for solving the technical problem is characterized in that the method has the steps of:

a) introducing the adhesive onto or into the bearing ring or onto or into the component, wherein the adhesive has no adhesive properties;

b) joining the bearing ring and the component to a desired relative position;

c) activating an adhesive such that the adhesive achieves adhesion between the bearing ring and the component.

Currently, adhesion is understood to be the attachment between the adhesive and the bearing ring or the component surface.

Thus, the joining between the components is performed in a non-bonded state of the adhesive. The adhesive is only "activated" after the precise relative position between the parts to be joined has been reached, in order to establish the bond.

The introduction of the adhesive according to step a) above may be achieved by means of an injection process. After the injection of the adhesive, the adhesive is cured and then maintained at a certain consistency again, so that the adhesive does not stick and can therefore be advantageously joined. After which the adhesive is activated and the bond is established thereby.

Alternatively and preferably, the introduction of the adhesive according to step a) above is effected by the introduction of a solid body consisting of the adhesive. The introduction of the adhesive, i.e. the introduction of the adhesive, is preferably effected thereby

a') forming an annular groove in a bearing ring or component, e.g. by turning an annular groove, and subsequently

a') filling said recess with a solid body consisting of an adhesive.

The solid body composed of the adhesive preferably has the shape of a hollow cylinder. The adhesive can be designed particularly advantageously in the shape of a hollow cylinder and with a cut-out at a circumferential position. The cut-out can extend in the axial direction of the hollow cylindrical adhesive body.

Activation of the adhesive according to step c) above may be achieved by heating, in particular by induction.

Activation of the adhesive may also be performed by applying ultrasonic waves.

In a preferred embodiment of the invention, the activation of the adhesive is effected by supplying a second adhesive component which reacts with the adhesive.

The flow of adhesive can be limited axially between the bearing ring and the component after activation thereof by means of at least one blocking element. As blocking element, at least one sealing ring, preferably designed as an O-ring, can be considered. On the other hand, the blocking element can also be a calibration ring. The blocking element is preferably arranged in a ring groove in the bearing ring or the component.

The bearing ring is preferably an inner ring of a rolling bearing, and the component is then a shaft. However, it is equally possible for the bearing ring to be the outer ring of a rolling bearing, the component being the housing.

The proposed method has the advantage that various materials with different values of the (material) properties can be joined to one another without problems.

Furthermore, the operational safety is increased, since a loosening of the connection between the bearing ring and the component (in particular between the bearing inner ring and the shaft) can be avoided.

The accuracy (the inclined position) of the bearing ring relative to the component is also improved by the adhesion.

The proposed solution also makes it possible to improve the dimensional accuracy and the surface quality of the joint in a simple manner, since the bridging can be better adapted to manufacturing tolerances.

The adhesive is preferably introduced or injected as a semi-finished product (in particular in the form of a sleeve) into the bearing bore.

Depending on the requirements on the precision of the bearing, it may also be of interest to calibrate the glue introduced into the perforations or to apply calibrated gaskets.

Various embodiments of the present invention are shown in the drawings. In the drawings:

figure 1 is a radial section of a ball bearing for supporting a shaft,

figure 2 is a side view corresponding to figure 1,

figure 3 is an enlarged view of the ball bearing according to figure 1,

FIG. 4 shows a first alternative design of the ball bearing according to FIG. 3 and

fig. 5 shows a second alternative design of the ball bearing according to fig. 3.

Fig. 1 to 3 show a ball bearing 8 consisting of an inner ring 1 and an outer ring 9, between which inner ring 1 and outer ring 9 rolling elements in the form of balls 10 are arranged. A component 2 in the form of a shaft is supported by bearings 8. For this purpose, the bearing inner ring 1 is connected to the shaft 2. Not shown is the bearing cup 9 fixed in a housing, not shown.

In order to form a fixed connection between the bearing inner ring 1 and the shaft 2, an adhesive is provided. The adhesive 3 to be used has a special design in this embodiment. I.e. an adhesive having a solid consistency at typical ambient temperatures (between 0 c and 50 c) is used (details and examples are further described below). A part is produced from the adhesive which is mechanically stable at normal ambient temperatures.

In the present embodiment, the adhesive 3 is produced as a thin-walled hollow cylindrical component. The sleeve-shaped part has a cut-out 5 at a circumferential position (see fig. 2).

The inner bearing ring 1 has, on the surface facing the shaft 2, a turned annular groove (best seen in fig. 3) having a depth equal to or slightly less than the thickness of the part of the hollow cylindrical adhesive 3. The groove for the adhesive part can also be designed deeper, which facilitates the use of adhesives with volume expansion properties (addition of a fermentation expanding agent). Thereby filling the narrow gap.

It is also possible to insert a hollow-cylindrical part made of the adhesive 3 into the recess 4. The adhesive 3 is placed in the recess 4 in the form of a snap fit due to the cut 5.

The adhesive not only has a solid consistency at typical ambient temperatures, but also has no adhesive properties. The bearing ring 1 and thus the entire bearing 8 can be moved without difficulty to the desired position of the connection of the components 1 and 2 after the adhesive 3 has been introduced into the groove 4 on the shaft 2. This is also done without causing any contamination in the boundary area adjoining the adhesive, since the adhesive has not yet been adhesive.

If the desired or required relative position between the bearing ring 1 and the shaft 2 is reached, the adhesive 3 is activated, i.e. turned to a state in which it exerts an adhesive effect. As a result of which a permanent indirection between the bearing ring 1 and the shaft 2 is established. The adhesive effect is also produced here in the adjacent region of the narrow fitting gap or clearance.

Activation is performed according to the adhesive selected. In the case of hot-melt adhesives (see below), activation can be effected by the action of heat, in particular by induction.

Alternatively, it may be provided that ultrasonic waves are applied to develop the adhesive properties of the adhesive 3.

Another alternative is to add a second component to the adhesive 3 so that the bond between the parts 1 and 2 is established as a result of the induced chemical reaction.

Fig. 4 and 5 show an expanded design of the solution according to fig. 1 to 3.

In fig. 4 the joint area between the inner surface of the inner ring 1 and the outer surface of the shaft 2 is sealed by two sealing rings 6 in the form of O-rings.

In the embodiment according to fig. 5, two sizing rings 7 with corresponding bearing action are used.

The following should be noted for the adhesive to be used:

first, readily meltable adhesives (also known as "Hotmelts") can be used. The fusible adhesive is solid at room temperature, which is advantageous for the present invention. It can be processed by melting, i.e. it exerts its adhesive effect when heated. The activation is thus carried out by temperature. The hot adhesive achieves an adhesive bond. The adhesive is then cooled and solidified, so that the connection is firm. This enables a quick assembly in an advantageous manner.

A sleeve can be simply formed from a solid hot melt adhesive and then placed into a recess (groove) in a bearing surface of a bearing ring.

Contact adhesives may also be used.

Furthermore, chemically hardening adhesives can be used. In this adhesive, also referred to as reactive adhesive, the chemical constituents used for the adhesive are introduced into the joint in suitable proportions. Then, the hardening and the strengthening are realized through the chemical reaction of the components. According to the invention, use is preferably made, however not only of systems of only two (or more) components. In these systems the adhesive consists of individual components, namely a component a and B or a binder (also known as a resin) and a hardener, which are brought into contact in the appropriate proportions before application. By contacting with each other, chemical reactions between the components separately present in advance are initiated to form an adhesive polymer.

Furthermore, adhesives which harden without oxygen can be considered. The adhesive is used as a one-component system. The (modified) acrylate monomer used hardens according to a radical chain mechanism similar to methyl methacrylate. In this case, in particular, when the adhesive is sealed off from the surrounding air in narrow metal joints, the hardening reaction only begins when oxygen is excluded, i.e., oxygen-free, and when metal ions are present. Only metallic materials can be bonded, which is advantageous for the present invention, since hardening requires free metal ions as reactants.

Other preferred adhesives which can be advantageously used in the present invention are radiation-hardening adhesives. In these adhesives used as one-component systems, they harden to solid polymers by free-radical polymerization, in which the irradiation by ultraviolet light (or other irradiation sources, such as electron rays) causes the formation of initial free radicals. The wavelength of the ultraviolet light must be precisely matched to the adhesive system used. The curing is performed by irradiation of ultraviolet rays.

A plurality of variants are possible here:

first of all, uv-acrylates are known. The UV-curable adhesive which crosslinks in the liquid state by free radicals consists essentially of monomers and photoinitiators. In this state the adhesive is easy to apply (dosieren). The photoinitiator is split into free radicals by the action of ultraviolet radiation. These radicals cause the formation of polymer chains. In the hardened state, the uv adhesives consist of crosslinked polymer chains.

Furthermore, cationic epoxy resins (epoxy-adhesives) can be used for bonding opaque substrates, which is advantageous in this embodiment. Unlike free-radically cured acrylate adhesives, cationically cured adhesive systems can continue to cure in the dark after sufficient activation with ultraviolet light. Cationic epoxies may also be used in ultraviolet light transmissive parts, as in materials that are not ultraviolet light transmissive. In the latter case, the adhesive must be activated after application, but before bonding by the ultraviolet beam. The activated adhesive has a limited open time of the joined parts.

In contrast, two-component (dual) cured products obtained by more than two curing mechanisms are suitable for application in truly shaded areas where no radiation source is accessible. The hardening in the shaded area is effected either by air humidity in the presence of metal in the case of gas tightness or by heat supply.

In phenolic resin adhesives, the basic building blocks are phenol (or phenol derivatives) and formaldehyde, which are polycondensed into a polymer. In the bonding technique, a mixture of a phenol resin and a formaldehyde donor which have not been subjected to high molecular polymerization is used. This mixture is introduced as a solution or powder into the bond joint and the almost interrupted polycondensation reaction is continued by raising the temperature to about 160 to 180 ℃. The adhesives thus obtained have good heat resistance properties, so that the system can be used in particular in hot metal bonding.

List of reference numerals

Bearing ring 1 (inner ring)

2 parts (axle, shell)

3 adhesive

4 grooves

5 incision

6, 7 blocking element

6 sealing ring (O-ring)

7 sizing ring

8 Bearings (Rolling bearing, ball bearing)

9 bearing ring (outer ring)

10 rolling element (sphere)

Claims (18)

1. A method for fixing a bearing ring (1) on or in a component (2) by means of adhesion, characterized in that the method has the steps of:

a) introducing an adhesive (3) onto or into the bearing ring (1) or onto or into the component (2), wherein the adhesive (3) does not yet have adhesive properties;

b) -joining the bearing ring (1) and the component (2) in a desired relative position;

c) activating the adhesive (3) such that the adhesive achieves a bond between the bearing ring (1) and the component (2).

2. The method as claimed in claim 1, characterized in that the introduction of the adhesive (3) according to step a) of claim 1 is effected by means of an injection molding process.

3. The method as claimed in claim 1, characterized in that the introduction of the adhesive (3) as claimed in step a) of claim 1 is effected by introducing a solid body consisting of the adhesive (3).

4. A method as claimed in claim 3, characterized in that the introduction of the glue (3) according to step a) of claim 1 is effected by

A') an annular groove (4) is formed in the bearing ring (1) or the component (2);

a') the solid body consisting of the adhesive (3) is introduced into the recess (4).

5. The method as claimed in claim 4, characterized in that the solid body consisting of the adhesive (3) has a hollow-cylindrical structure.

6. Method according to claim 5, characterized in that the adhesive (3) having a hollow cylindrical configuration has a cut (5) at a circumferential position.

7. Method according to claim 6, characterized in that the cut (5) extends in the axial direction of the hollow cylindrical glue body.

8. Method according to one of claims 1 to 7, characterized in that the activation of the adhesive (3) according to step c) of claim 1 is effected by heating.

9. The method of claim 8, wherein said heating is accomplished by induction.

10. Method according to one of claims 1 to 7, characterized in that the activation of the adhesive (3) according to step c) of claim 1 is effected by applying ultrasound.

11. The method as claimed in one of claims 1 to 7, characterized in that the activation of the adhesive (3) according to step c) of claim 1 is effected by feeding a second adhesive component which reacts with the adhesive (3).

12. Method according to one of claims 1 to 11, characterized in that the flow of the glue (3) is limited axially between the bearing ring (1) and the component (2) after its activation by means of at least one blocking element (6, 7).

13. Method according to claim 12, characterized in that at least one sealing ring (6) is used as the blocking element (6, 7).

14. Method according to claim 13, characterized in that the sealing ring (6) is an O-ring.

15. Method according to claim 12, characterized in that at least one sizing ring (7) is used as the blocking element (6, 7).

16. Method according to one of claims 12 to 15, characterized in that the blocking elements (6, 7) are arranged in ring grooves in the bearing ring (1) or the component (2).

17. Method according to one of claims 1 to 16, characterized in that the bearing ring (1) is an inner ring of a rolling bearing and the component (2) is a shaft.

18. Method according to one of claims 1 to 16, characterized in that the bearing ring (1) is an outer ring of a rolling bearing and the component (2) is a housing.