DD253655A1 - SPRING COLLOCK WITH SPECIAL RIBBED BODY DESIGN - Google Patents

Abstract

Spring-loaded bearings with special Wälzkörpergestaltung, which is particularly used in statically indeterminate storage, or when hard shocks are to survive without damage, or if it depends on backlash, or pay to critical bending rotary pay. The rolling element is characterized in that it is free of material in the vicinity of its axis of rotation and thus becomes a shaped spring. Fig. 3 illustrates a rolling element. Fig. 3.

Description

Characteristic of the known technical solutions

Known is a considerable number of rolling bearing types and designs with different properties for different functions. They have radial clearance and are inelastic.

Also known are manifold structures for receiving these bearings in housing, the u.a. fulfill the partial function of the yielding bearing. These special constructions are complex and require special experience.

Also known are elastic couplings whose application mitigates the deleterious effects of static indeterminacy due to rigid shaft coupling. However, their application is not possible in every application.

Also known are elastic internals in roller bearings based on Stoffedem and of molded springs (ζ., Β. DD 39472). Although they ensure the purpose of the resilient bearing, but do not avoid the radial clearance and affect the accuracy of guidance.

Object of the invention

The goal is a spring-loaded rolling bearing without radial internal clearance, which is manufactured as standard with defined characteristics. It is intended to supplement the range of rolling bearing designs for special applications.

Explanation of the essence of the invention

The invention has for its object to provide a resilient bearing high guidance accuracy and to be influenced by the manufacturer spring constant, which works without radial clearance in cold and warm condition, has an improved static and dynamic load capacity and is also easier due to reduced material usage

The features of the invention

They consist in that the rolling elements are designed as shaped springs with defined spring constants by the space is made free of material in the vicinity of its axis of rotation and their installation takes place in the rolling space between you and outer ring under tension.

As a result, no clearance is present in the installed state, with an increase in temperature of the inner ring relative to the outer ring, the bias increases and in the reverse operating state, it decreases, without reaching the value zero.

The theoretically circular contour of the rolling element in the coaxial section through the rolling bearing is thus elliptical by millimeter fractions.

Due to the operating load, the loaded rolling elements are deformed more and the relieved approach the circular shape. The load limit is reached if radial clearance arises at the unloaded rolling elements.

The increase in the fatigue life (pitting) in the bearing according to the invention is based on two influencing variables, which are features of the invention.

On the one hand, when the load is increased as a result of the deformation, the osculation is improved and, on the other hand, the so-called point load no longer exists as a result of the elastic deformation.

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While with rigid rolling elements at times only one rolling element absorbs the entire load, in the case of the rolling elements which are resilient according to the invention, all that are located within the half shell, which lies in the loading direction, carry, albeit with different proportions.

Another feature of the invention is that the free space in the vicinity of the axis of rotation of the rolling elements not only brings a saving in material, but can also serve as a receptacle for fixing and guiding the rolling elements.

embodiment

The invention will be explained in more detail below using the example of a Zylinderrolleniagers, with reference to figures. Show it

Fig. 1: the view of a rolling element according to the invention for a cylindrical roller bearing and the course of the bending moment on

the scope.

Fig. 2: The mechanism of the load distribution on several rolling elements proportional to the deformation and Fig. 3: a representation of a pin in the material-free space in the vicinity of the axis of rotation of the rolling body.

A rolling element 1 has the shape of a hollow cylinder with an outer diameter D and a wall thickness s. It is loaded radially by a force F, which it has to transfer from an inner ring 2 to an outer ring 3. As a result of a space 5 free in the vicinity of its axis of rotation 4, the rolling element 1 becomes a shaped spring which is subjected mainly to bending stress and bending deformations, the maximum moment Mm occurring under the force

and by a quarter of a circumference offset the moment

Mn ₂ = Mm ₂ (1 - "/ 2) occurs

 Assuming a running width b of the rolling body, results in a maximum bending stress

b_ 2 / D / "-1 \

π b · s The deformation of both half-shells of the rolling body, ie, its flattening is then at a modulus of elasticity E.

^V 2 "E b ^{v 7} S ~ 'Λ4 Tf

The spring constant c of the rolling element according to the invention then results

4d E b

c =

3 9C ² - 24 ( ^D A - 1) ³ s

While with rigidly assumed rolling elements, the radial bearing load Fr fully transfers to a single rolling element, the distribution of forces on the individual rolling elements can be calculated with a linear spring characteristic. After Fig. 2 applies

/ 4 Pr = E ₁ (1 + 2 Σ

where η is the number of rolling bearings.

A material saving results ostensibly by eliminating the material in the free space 5 compared to the conventional design.

Part of this saving may be offset by the more dense packing of the rolling elements according to the invention, i.

their larger number per warehouse.

The solution according to the invention allows a much more expedient design of the cage, which conventionally comprises the rolling elements on both sides and thus requires a large distance of the individual rolling elements and considerable additional effort with a larger radius of friction.

Figure 3 shows that the function of the cage is better fulfilled by having pins 6 which engage in the free space 5 of the rolling element and there because of the small radius of friction and the elliptical formation of the free space find similar conditions as the pin a sliding bearing with lemon game.

By eliminating the outer enclosure of the rolling element through the cage better utilization of the Wälzraumes is possible.

For a bearing according to the invention, which in its external dimensions corresponds approximately to the NU 2211, the following conditions are to be presented:

On a dm = 78mm η = 20 rolling elements with D = 10mm can easily be accommodated, which corresponds to a = 18 °.

S = 2 mm, b = 12mm. According to a mean bearing clearance of 40 μτη in the NU 2211, a preload for a rolling element of 20μΐη is set, which corresponds to a preload force of about 1.7 KN.

Assuming a dynamic bearing load of F _r = 6KN, results for a rolling element F ₁ = 1.05KN, which corresponds to an additional deformation of 12.5 / xm. The total load due to preload force and operating force results in a maximum bending load of 880 MPa.

Claims (2)

1. A spring-loaded roller bearing with a special Wälzkörpergestaltung, characterized in that a rolling element by forming a material-free space in the vicinity of its axis of rotation to the form spring and its play-free installation under defined bias and deformation is such that the calculated limit of the bearing load by the disappearance of the bias on the load-free side is determined that the predictable spring constant is chosen so that always contributes a scarce half of all built-in rolling the operating load, whereby the ratio of the bearing load to Wälzkörperbelastung is favorably changed and that the material-free space in the vicinity of the axis of rotation of the rolling elements both its position as well as by the nature of its elastic deformation is suitable for receiving pins on which both a cage and other attachments can be attached. 2. A spring-loaded roller bearing according to claim 1, characterized in that both the demand for the manufacturing accuracy and the surface hardness is lower in contrast to the demand on the bending fatigue strength, which is for the material of the solution according to the invention an increased importance. For this 2 pages drawings
field of use The invention relates to a resilient rolling bearing with a special Wälzkörpergestaltung, which can be used in mechanical engineering in particular where a statically indeterminate storage is provided, or due to rigid coupling of two waves, the storage is statically indeterminate. Other applications arise from a deliberate reduction of the critical bending speed or in the presence of jerky static load.