DE112020001379T5 - Deep groove ball bearings - Google Patents

Abstract

A deep groove ball bearing is provided for use in a guide roller of a tensioning bracket in a film stretching machine which contains a tape holder which is able to reduce lubricant leakage. A radial gap ei between the inner diameter surface 4a of the holder and the outer diameter surface 1b of an inner ring is related to the size of a ball 3 (diameter Dw), which is expressed as: 0.11 × Dw ei <0.35 × Dw. By setting this ratio, lubricant scraped off the surface of the ball 3 by the holder 4 is prevented from leaking from a gap g between one end of an inner diameter side of a seal plate 5 and the outer diameter surface 1b of the inner ring.

Description

Technical part

The present invention relates to deep groove ball bearings for use in guide rollers of tensioning brackets, for example in film stretching machines, and in particular to a deep groove ball bearing which is able to reduce the leakage of lubricant.

State of the art

As a conventional roller bearing shows 7th a deep groove ball bearing.

This deep groove ball bearing consists of an inner ring 101, an outer ring 102, balls 103, a band holder 104 and sealing plates 105.

Each of the sealing plates 105 is fixed with its outer diameter side to an axial end portion of the outer ring 102, and its inner side serves as a free end facing the inner ring 101 with a small gap g.

The balls 103 are held by the tape holder 104, and when the bearing rotates, the pocket edges 104b of the holder scrape off the lubricant adhering to the surfaces of the balls 103. The scraped lubricant accumulates, adheres to an outer surface 101b of the inner ring 101, and then sometimes leaks out of the bearing through the gap g between the seal plate 105 and the inner ring 101.

Conventional techniques for preventing lubricant from leaking outside the deep groove ball bearing are described in Patent Literature 1 and Patent Literature 2.

Citation list

Patent literature

• Patent Literature 1: JP-A 2004-044682
• Patent literature 2: JP-B 5424573

Summary of the invention

Technical problem

In the method described in Patent Literature 1, a crown holder is used. The pockets of the crown holder have an opening on the side of the outer diameter and an opening on the side of the inner diameter, the diameters of which are both equal. The thickness of the holder is greater on a side that is further out than the pitch diameter of the rolling element than that on the inside diameter side. The patent literature claims that the arrangement reduces the amount of lubricant scraped from the surface of the rolling element through the pocket of the holder and reduces the local storage of the scraped lubricant, and therefore it is possible to prevent leakage of To prevent lubricant from leaking outwards.

In the technique described in Patent Literature 1, however, the distance between the inner diameter of the holder and the outer diameter of the inner ring sometimes becomes too small depending on the dimensions and / or shapes of the inner ring, causing the lubricant scraped off the holder to adhere to the inner ring and then exits the camp to the outside. To avoid this, it is necessary to limit the distance between the inner diameter of the holder and the outer diameter of the inner ring.

In addition, the amount of lubricant scraped from the pocket edges of the holder is proportional to the surface area of the rolling element, and whether or not the scraped lubricant adheres to the inner ring depends on the distance between the inner diameter of the holder and the outer diameter of the inner ring. For this reason, the inside diameter of the holder must be determined at the same time as the distance to the outside diameter of the inner ring, taking into account the diameter of the rolling element.

According to the technique disclosed in Patent Literature 2, a tape holder has arcuate recessed segments in its inner diameter at the locations where pockets are located, viewed in the axial direction. By spacing the segments from the outer diameter of the inner ring in this way, the patent literature has shown that lubricant scraped from the pockets of the holder is prevented from adhering to the inner ring and then leaking out of the bearing.

However, the technique described in Patent Literature 2 requires a special shape of the holder and special devices to align the arcuate recesses of the holder with the circumferential position of the pockets, resulting in an increase in cost.

In addition, the recess described above has a structure in which the radial distance between the inner diameter of the holder and the outer diameter of the inner ring becomes smaller from the deepest part to the shallower part. Therefore, as the bearing rotates, the scraped-off lubricant accumulates along the shape of the recess and eventually adheres to the outer diameter of the inner ring. As a result, lubricant can leak.

It is therefore an object of the present invention to prevent leakage of lubricant without increasing the cost compared to conventional bearings.

the solution of the problem

In order to solve the above-described problems, the present invention provides a deep groove ball bearing comprising: an outer ring; an inner ring; a plurality of balls disposed between the raceway surface of the outer ring and the raceway surface of the inner ring; wherein the raceway surface of the outer ring and the raceway surface of the inner ring face each other; a holder for holding the balls equidistantly in a circumferential direction on the raceway surfaces of the inner ring and the outer ring; and at least one sealing plate attached to an axial end portion of the outer ring and having a gap between it and the axial end portion of the inner ring. In this arrangement, the holder is a tape holder which is provided by joining two annular parts, and further, the inner diameter surface of the holder and the outer diameter surface of the inner ring are passed through a radial gap egg separated, which has a relation to a diameter Dw of the sphere, which is expressed as follows: 0.11 × Dw ei <0.35 × Dw.

In other words, the setting 0.11 × Dw ≤ ei ensures that there is a radial gap between the holder and the inner ring egg exists, so that the lubricant scraped off the ball surface by the holder can be prevented from adhering to the surface of the inner diameter of the inner ring and then leaking out to the outside.

By setting ei <0.35 × Dw in a range in which the inner diameter of the holder is identical to the pitch diameter of the rolling element, deterioration in strength due to insufficient radial dimension of the holder can be avoided.

The deep groove ball bearing according to the present invention is suitable for a guide roller of a clamping bracket of a film stretching machine. In this case, the bearing is used to rotate the outer ring.

Advantageous Effects of the Invention

As described, by adjusting the ratio between the radial gap egg between the inner diameter surface of the holder and the outer diameter surface of the inner ring and the size of the ball (diameter Dw ) to 0.11 × Dw ei <0.35 × Dw, deterioration in the strength of the holder can be avoided and leakage of lubricant can be effectively prevented, and since it is not necessary to form a specially shaped holder, the invention can also use one Prevent increases in costs.

Figure list

• 1 Fig. 13 is an enlarged partial cross-sectional view of a deep groove ball bearing according to an embodiment of the present invention.
• 2 FIG. 14 is a perspective view of a retainer incorporated in the deep groove ball bearing of FIG 1 is used.
• 3 FIG. 13 is a perspective view of one half of the holder as part of the holder in FIG 2 .
• 4th Figure 3 is a schematic block diagram of a film stretching machine.
• 5 Fig. 13 is a cross-sectional view showing a bracket and its vicinity in the film stretching machine.
• 6th Fig. 13 is a graph showing the result of a test in which the amount of the lubricant leaking from the bearing was measured in cases where ei is appropriately varied.
• 7th Fig. 3 is an enlarged partial cross-sectional view of a conventional deep groove ball bearing.

Description of the embodiments

In the following, the embodiments of the present invention will be described with reference to the accompanying drawings.

A deep groove ball bearing according to an in 1 The embodiment of the present invention shown comprises an inner ring 1 with a tread 1a , an outer ring 2 with a tread 2a , a variety of balls 3 , which are arranged between the two running surfaces, a holder 4th who made the multitude of balls 3 holds, and non-contact sealing plates 5 , which are arranged on both sides to seal the storage room. The one from the inner ring 1 , the outer ring 2 and the sealing plates 5 surrounding space is sealed with lubricant (not shown).

As in a perspective view of 2 shown is the holder 4th annular and has pockets 50 at several points in the circumferential direction. Each pocket 50 has a spherically recessed inner surface for receiving one of the balls 3 . The holder 4th consists of two annular holder halves 51, which in a perspective view of 3 and which, as in 2 shown by axial abutment and subsequent Connect with rivets 53, which are inserted through rivet holes 52, are mated. Each of these holder halves 51 has a plurality of spherical shell sections 50A, each of which has an inner surface in the form of a partial sphere, which represents one half of the pocket 50. Flat plate-shaped sections 51a for connecting two adjacent pockets 50 alternate with the spherical shell sections 50A in the circumferential direction. The spherical shell portion 50A serving as part of the spherical shell is a bulged portion whose inner and outer surfaces are spherical like the shape of a countersink. In an axially projected view, the holder half 51 has an annular shape with a constant radial width over the entire circumference.

The holder 4th has an inside diameter represented by a single circle. As in 1 shown are the inner diameter area 4a of the holder and the outer diameter area 1b of the inner ring with regard to the radial minimum distance (radial gap egg ) and the size (diameter Dw ) the ball 3 in the following relation to each other: $$0.11\times \text{Dw}\le \text{egg}<0.35\times \text{Dw}$$

First, the setting 0.11 × Dw≤ ei ensures that between the holder 4th and the inner ring 1 a radial gap egg exists so that it can be prevented from falling from the surface of the sphere 3 by the holder 4th scraped off lubricant on the outer surface 1b of the inner ring adheres and then emerges to the outside.

6th Fig. 13 is a graph showing the result of a test in which the amount of lubricant leaked from the bearing was measured while ei was appropriately varied. From this diagram it can be concluded that the lower limit of ei should be 0.11 × Dw.

• • Musterlager: Rillenkugellager 6202; Halter = Band, Stahlblechkäfig; Dichtungsplatte = Berührungslose Stahlblechabschirmung; Art des innen versiegelten Schmiermittels = Fluor-Fett; Menge des innen versiegelten Schmiermittels = 30% des Innenraums des Lagers
• • Lagerposition: Vertikal
• • Rotationsgeschwindigkeit: 3.000 min-1 (Rotation des Außenrings)
• • Testzeit: 3 Stunden

The test was carried out under the following conditions:

• • Sample bearing: deep groove ball bearing 6202; Holder = band, sheet steel cage; Sealing plate = non-contact sheet steel shielding; Type of internally sealed lubricant = fluorine grease; Quantity of internally sealed lubricant = 30% of the internal space of the bearing
• • Storage position: vertical
• • Rotation speed: 3,000 min-1 (rotation of the outer ring)
• • Test time: 3 hours

The test result showed that the amount of the leaked lubricant decreased with increasing ei, and the downward trend was particularly conspicuous under the condition when ei ≥ 0.11 × Dw. It follows that by setting egg ≒ 0.11 × Dw both the reduction in lubricant leakage and the strength of the holder can be guaranteed at a high level.

In an outer ring pivot bearing, the holder sticks 4th scraped off lubricant on the bracket 4th or the inner surface 5a of the seal plate and then becomes the outer ring by centrifugal force 2 emotional. However, the lubricant does not adhere to the inner ring 1 which the centrifugal force does not act on, so the lubricant does not accumulate and leak to the outside. For this reason, the invention offers a particular advantage in preventing lubricant leaks in outer ring rotary bearings.

In a further embodiment, ei is preferably set to ei <0.35xDw, specifically in a region in which the inner surface 4a of the holder is identical to the pitch circle diameter of the rolling element. This is to prevent deterioration in strength due to insufficient radial dimension of the holder 4th to avoid.

As described, by adjusting the ratio between the radial gap egg between the inner diameter surface 4a of the holder and the outer diameter surface 1b of the inner ring and the size (diameter Dw ) the ball 3 to 0.11 × Dw ei <0.35 × Dw, there is a deterioration in the strength of the holder 4th avoided and the leakage of lubricant effectively prevented.

The sealing plate 5 comprises an annular metal core 6 and a rubber-like member 7 which is integrally connected to the metal core 6 and the outer peripheral portion of which is fitted and fixed in a seal fixing groove 8 formed in an inner peripheral surface of the outer ring 2 is trained. The rubber-like member 7 is made of synthetic rubber, while the metal core 6 is made of a steel plate. The inner ring 1 is provided with a seal groove 9 formed by a circumferential groove at a position corresponding to an inner diameter portion of each seal plate 5 corresponds, with a gap g forming a labyrinth seal between an inner diameter end of the sealing plate 5 and the sealing groove 9 of the inner ring 1 forms. The seal attachment groove 8 and the seal groove 9 are made by cutting.

The deep groove ball bearing according to the present invention is suitable for a guide roller of a clamping bracket in a film stretching machine. When used as a guide roller for a clamp in In a film stretching machine, the bearing is used to rotate the outer ring.

4th and 5 show an example of a film stretching machine 16 using the deep groove ball bearing according to the present invention.

As in the schematic drawing of 4th is shown includes the film stretching machine 16 an extruder 19 which melts a thermoplastic polymer mixture 17 and extrudes the material in the form of a sheet 18 which is in an unstretched state; a cooling drum 20 that receives the extruded film 18; a feed roller 21 that feeds the film 18 after it has been cooled by the cooling drum 20; a water cistern 22 which controls the humidity of the film 18 fed from the feed rollers 21; and a water drainage device 23 which sandwiches the moisture-controlled film 18 from the water cistern 22 while removing water droplets from the surfaces. The machine also comprises a biaxial stretching machine 29 which carries out biaxial stretching of the dripped film 18 in the longitudinal and transverse directions, and a collecting roller 30 which rolls up the film 18 formed by the biaxial stretching machine 29.

The biaxial stretching machine 29 comprises, as an essential element, a lateral stretching mechanism 40, which is shown in FIG 5 is shown. The side stretching mechanism 40 includes tension brackets 31 . The side stretching mechanism 40 comprises guide rails 33, 34 arranged on the two sides, ie the left and right sides of the fed film 18, so that the two sets of guide rails are gradually spaced apart as the rails move forward move, and a variety of clamps 31 which revolve on the guide rails 33, 34 in a direction of movement of the web.

The tension bracket 31 comprises a grip area 32 for gripping an edge area of the film 18 and guide bearings 35, 36, which roll on the guide rails 33, 34, which are each laid as a closed loop. A pair of the clamps 31 grips with its gripping sections 32 the edge sections on two sides of the film 18 and moves on the guide rails 33, 34, whereby the film 18 is stretched in lateral directions. Each set of the guide rails 33, 34 is a combination of two types of rails, ie the guide rails 33 have their guide surface in the horizontal direction, while the guide rail 34 has its guide surface in the vertical direction. The guide bearings 35, 36 of the clamping bracket 31 are for unrolling and guiding the clamping bracket 31 on each of the guide rails 33, 34 responsible. Of these guide bearings 35, 36, the guide bearing 35, which rolls on the guide surface in the horizontal direction, is fastened to a fastening shaft 37 which is laid in the horizontal (lateral) direction. The guide bearing 36, which rolls on the guide surface in the vertical direction, is fastened to a fastening shaft 38 set up in the vertical (upright) direction. The guide bearing attached to this upright mounting shaft 38 is supported by the deep groove ball bearing in FIG 1 provided in accordance with the present invention.

A film stretching machine uses a large number of bearings for the guide rollers. Since the deep groove ball bearing of the present invention used as a bearing for the guide roller is the non-contact seal plate 5 is used, which has a low torque, it is possible to reduce the electrical power consumed by the entire system. In a further embodiment, the sealing plate 5 however, a so-called contact seal, which does not have a labyrinth sealing gap (g) between the inside end of the sealing plate 5 and the sealing groove 9 of the inner ring 1 having.

Through the training of the holder 4th With a simple circular inner diameter, the deep groove ball bearing according to the invention can also be used on a guide roller of a tensioning bracket in a film stretching machine without increasing the costs compared to conventional bearings. The holder 4th has a wall thickness that can be selected according to its material properties and strength. The holder 4th can also be made of cold-rolled steel or stainless steel, and nitriding treatment can be performed if necessary.

The balls 3 can be made of ceramics in addition to steel. Also, the lubricant sealed in the bearing can be a lubricant in which a fluorine oil is used as the base oil and PTFE and / or boron nitride is used as a thickener.

The present invention is not limited to the embodiments described so far, and it is obvious that the invention can be modified in many other ways within the scope of the present invention. The scope of the present invention is defined by the claims, and includes all equivalents thereto and all modifications therein.

List of reference symbols

1:

Inner ring

1a:

Track surface

1b:

Outer diameter surface of the inner ring

2:

Outer ring

2a:

Track surface

3:

ball

4:

holder

4a:

Inner diameter surface of the holder

5:

Sealing plate

16:

Film stretching machine

31:

Tension bracket

Dw:

diameter

egg:

Radial gap

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• JP 2004044682 A [0006]
• JP 5424573 B [0006]

Claims (3)

A deep groove ball bearing comprising: an outer ring (2); an inner ring (1); a plurality of balls (3) arranged between the raceway surface (2a) of the outer ring and the raceway surface (1a) of the inner ring, both raceway surfaces facing each other; a holder (4) for holding the balls (3) equidistantly in a circumferential direction on the running surfaces of the inner ring (1) and the outer ring (2); and at least one sealing plate (5) which is attached to an axial end portion of the outer ring (2) and has a gap (g) between itself and the axial end portion of the inner ring (1), wherein the holder (4) is a band holder which is made by joining two annular parts, and a radial gap ei between the inner diameter surface (4a) of the holder and the outer diameter surface (1b) of the inner ring has a relationship with a diameter Dw of the balls (3), which is expressed as follows: $$0.11\times \text{Dw}\le \text{egg}<0.35\times \text{Dw}\text{.}$$

Deep groove ball bearings Claim 1 used to rotate the outer ring. Deep groove ball bearings Claim 1 or 2 , for use in a guide roller of a clamping bracket in a film stretching machine.

Images