WO2020195586A1 - Deep groove ball bearing - Google Patents

Abstract

Provided is a deep groove ball bearing provided with a corrugated cage that is used in a guide roller of a tenter clip of a film stretching machine and can suppress grease leakage. A radial-direction gap ei between a radially-inner surface 4a of a cage and a radially-outer surface 1b of an inner race and a size (diameter Dw) of a ball 3 are set to satisfy the relationship 0.11 × Dw ≤ ei < 0.35 × Dw. As a result, grease scraped from the surface of the ball 3 by the cage 4 is prevented from leaking to the outside via a gap g between a radially-inner edge of a sealing plate 5 and the radially-outer surface 1b of the inner race.

Description

Deep groove ball bearing

The present invention relates to, for example, a deep groove ball bearing used for a guide roller of a film stretching machine tenta clip, particularly a deep groove ball bearing capable of suppressing grease leakage.

Conventionally, as one of the rolling bearings, there is a deep groove ball bearing shown in FIG.

This deep groove ball bearing is composed of an inner ring 101, an outer ring 102, a ball 103, a waveform cage 104, and a sealing plate 105.

The outer diameter side of the sealing plate 105 is fixed to both ends of the outer ring 102 in the axial direction, the inner diameter side is the free end, and the sealing plate 105 faces the inner ring 101 with a minute gap g.

The ball 103 is held by the corrugated cage 104, and when the bearing rotates, the grease adhering to the surface of the ball 103 is scraped off by the cage pocket edge 104b. The grease that has been scraped off and accumulated may adhere to the outer diameter surface 101b of the inner ring 101 and leak to the outside of the bearing through the gap g between the sealing plate 105 and the inner ring 101.

Conventionally, a technique for preventing grease from leaking to the outside of a deep groove ball bearing is disclosed in Patent Document 1 or Patent Document 2.

Japanese Unexamined Patent Publication No. 2004-044682 Japanese Patent No. 5424573

By the way, the technique disclosed in Patent Document 1 uses a crown type cage, makes the pocket outer diameter side opening diameter and the inner diameter side opening diameter of the crown type cage the same, and is outside the rolling element pitch diameter. By making the wall thickness of the cage on the diameter side larger than that on the inner diameter side, the amount of grease scraped from the surface of the rolling element to the cage pocket is reduced, local retention is suppressed, and leakage to the outside is prevented. It is supposed to be possible.

However, in the technique disclosed in Patent Document 1, the gap between the inner diameter of the cage and the outer diameter of the inner ring becomes smaller depending on the size and shape of the inner ring, and the grease scraped off by the cage adheres to the inner ring to the outside of the bearing. May leak to. In order to avoid this, it is necessary to limit the distance between the inner diameter of the cage and the outer diameter of the inner ring.

Furthermore, the amount of grease scraped off the edge of the cage pocket is proportional to the surface area of the rolling element, and whether or not the scraped grease adheres to the inner ring depends on the distance between the inner diameter of the cage and the outer diameter of the inner ring. .. Therefore, it is necessary to determine the inner diameter of the cage at the same time as the distance from the outer diameter of the inner ring while considering the diameter of the rolling element.

Further, in the technique disclosed in Patent Document 2, the grease scraped off in the cage pocket is removed by denting the inner diameter portion of the pocket position when the waveform cage is viewed from the axial direction in an arc shape and keeping it away from the outer diameter of the inner ring. This is to prevent it from adhering to the inner ring and leaking from the bearing.

However, the technique of Patent Document 2 requires a special shape and a jig to align the arcuate recess of the cage with the circumferential position of the pocket, resulting in an increase in cost.

In addition, the above recess has a structure in which the radial distance between the inner diameter of the cage and the outer diameter of the inner ring approaches from the deepest part to the shallowest part. Therefore, as the bearing rotation time elapses, the grease scraped off along the shape of the bearing accumulates, which may eventually adhere to the outer diameter of the inner ring and cause grease leakage.

Therefore, the present invention has an object of preventing grease leakage without increasing the cost as compared with the conventional bearing.

In order to solve the above-mentioned problems, the present invention presents an outer ring, an inner ring, a plurality of balls assembled between the outer ring raceway surface and the inner ring raceway surface, and the balls in the circumferential direction on the raceway surfaces of the inner ring and the outer ring. In a deep groove ball bearing consisting of a cage that holds evenly distributed and at least one sealing plate that is fixed to the axial end of the outer ring and has a gap between the axial end of the inner ring, the cage is an annulus. It is a corrugated cage that combines two parts, and the relationship between the radial gap ei between the inner diameter surface of the cage and the outer diameter surface of the inner ring and the diameter Dw of the ball is 0.11 × Dw ≦ ei <0.35. It is set to × Dw.

That is, by setting 0.11 × Dw ≦ ei, the radial gap ei between the cage and the inner ring can be surely secured, so that the grease scraped from the surface of the ball to the cage adheres to the outer diameter surface of the inner ring. This can prevent leakage to the outside.

Further, by setting ei <0.35 × Dw and setting the inner diameter of the cage to the range until it matches the pitch diameter of the rolling element, it is possible to avoid a decrease in strength due to insufficient dimensions in the radial direction of the cage.

The deep groove ball bearing according to the present invention can be used as a guide roller for a film stretching machine tenta clip, and in that case, it is used for outer ring rotation.

As described above, the relationship between the radial gap ei between the inner diameter surface of the cage and the outer diameter surface of the inner ring and the size of the ball (diameter Dw) is set to 0.11 × Dw ≦ ei <0.35 × Dw. As a result, it is possible to avoid a decrease in the strength of the cage, effectively prevent grease leakage, and since the cage is not specially shaped, it is possible to prevent an increase in cost.

It is a partially enlarged sectional view of the deep groove ball bearing which concerns on embodiment of this invention. It is a perspective view of the cage used for the deep groove ball bearing of FIG. It is a perspective view of the cage half body which is a constituent member of the cage of FIG. It is a schematic block diagram of a film stretching machine. It is sectional drawing which shows the peripheral part of the tenta clip in a film stretching machine. It is a graph which shows the test result which measured the amount of grease leakage from the bearing which changed ei appropriately. It is a partially enlarged sectional view of the conventional deep groove ball bearing.

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

In the deep groove ball bearing of FIG. 1 according to the embodiment of the present invention, a plurality of balls 3 are interposed between the raceway surface 1a of the inner ring 1 and the raceway surface 2a of the outer ring 2, and the cage 4 holds the balls 3. Is provided, and non-contact type sealing plates 5 for sealing the bearing space are provided on both sides. Grease (not shown) is sealed in the space surrounded by the inner ring 1, the outer ring 2, and the sealing plate 5.

As shown in the perspective view of FIG. 2, the cage 4 has pockets 50 for holding each ball 3 at a plurality of locations in the circumferential direction, and the inner surface of each pocket 50 has a concave spherical surface shape. is there. The cage 4 is formed by stacking two annular cage half bodies 51 shown in a perspective view in FIG. 3 facing each other in the axial direction and inserting the rivet 53 into the rivet hole 52 as shown in FIG. They are joined together and configured as one. These cage half bodies 51 have a plurality of spherical shell-shaped plate portions 50A having a partially spherical shell shape whose inner surface forms half of the pocket 50, and the flat plate portion 51a which is a portion between adjacent pockets 50. It is assumed that the spherical shell-shaped plate portions 50A are alternately arranged in the circumferential direction. The spherical shell-shaped plate portion 50A is a portion that becomes a part of the spherical shell, in other words, is a counter-sink-shaped bulging portion in which both the inner and outer surfaces are spherical. The projected shape of the cage half body 51 in the axial direction is a ring shape having a constant radial width over the entire circumference.

The inner diameter of the cage 4 is a single circular shape, and as shown in FIG. 1, the minimum radial distance (radial gap ei) between the inner diameter surface 4a of the cage and the outer diameter surface 1b of the inner ring and the size of the ball 3 The relationship with Sa (diameter Dw) is set as follows.
0.11 x Dw ≤ ei <0.35 x Dw

First, by setting 0.11 × Dw ≦ ei, the radial gap ei between the cage 4 and the inner ring 1 can be surely secured, so that the grease scraped from the surface of the ball 3 to the cage 4 is removed from the inner ring. It is possible to prevent it from adhering to the diameter surface 1b and leaking to the outside.
FIG. 6 is a graph showing the test results of measuring the amount of grease leakage from the bearing in which the ei is appropriately changed, and the result of reaching the lower limit of the ei to 0.11 × Dw can be derived from this graph.
The test conditions are as follows.
-Test bearing: Deep groove ball bearing 6202, cage = corrugated steel plate cage, sealing plate = non-contact type steel plate shield, filled grease = fluorine grease, grease filling amount: 30% of the space volume inside the bearing
・ Bearing posture: Vertical axis ・ Rotation speed: 3,000 min ^-1 (outer ring rotation)
-Test time: 3 hours As a result of this test, the amount of grease leakage decreased as ei increased, and showed a clear decreasing tendency especially when ei ≧ 0.11 × Dw. As a result, it was found that by setting ei≈0.11 × Dw, both suppression of grease leakage and cage strength can be achieved at a high level.

In the case of an outer ring rotating bearing, the grease scraped off by the cage 4 adheres to the cage 4 or the inner surface 5a of the sealing plate and moves to the outer ring 2 side by the action of centrifugal force, but is affected by the centrifugal force. It does not adhere to the inner ring 1 and does not accumulate or leak. Therefore, in the case of an outer ring rotating bearing, it is particularly effective in preventing grease leakage.

On the other hand, it is preferable that ei is ei <0.35 × Dw and the range is until the inner diameter surface 4a of the cage matches the pitch diameter of the rolling element. This is to avoid a decrease in strength due to insufficient dimensions of the cage 4 in the radial direction.

As described above, the relationship between the radial gap ei of the inner ring inner diameter surface 4a and the inner ring outer diameter surface 1b and the size of the ball 3 (diameter Dw) is set to 0.11 × Dw ≦ ei <0.35 × Dw. By doing so, it is possible to avoid a decrease in the strength of the cage 4 and effectively prevent grease leakage.

The sealing plate 5 is composed of an annular core metal 6 and a rubber-like member 7 integrally fixed to the core metal 6, and the outer peripheral portion is fitted into a seal mounting groove 8 formed on the inner peripheral surface of the outer ring 2. It is fixed in the combined state. The rubber-like member 7 is made of synthetic rubber, and the core metal 6 is made of steel plate. A seal groove 9 composed of a circumferential groove is formed in the inner ring 1 at a position corresponding to the inner diameter portion of each sealing plate 5, and a labyrinth seal is provided between the inner diameter side end of the sealing plate 5 and the sealing groove 9 of the inner ring 1. The gap g to be formed is formed. The seal mounting groove 8 and the seal groove 9 are finished by turning.

The deep groove ball bearing according to the present invention can be suitably used as a guide roller for a film stretching machine tenta clip. When used as a guide roller for a film stretching machine tenta clip, it is used for outer ring rotation.

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

As shown in the schematic diagram in FIG. 4, the film stretching machine 16 includes an extruder 19 that melts the thermoplastic polymer compound 17 and extrudes it as an unstretched film 18, and a cooling drum 20 that receives the extruded film 18. A feed roller 21 that feeds the film 18 cooled by the cooling drum 20, a water tank 22 that applies a humidity control treatment to the film 18 fed by the feed roller 21, and a film 18 that has been humidity-controlled by the water tank 22 are sandwiched. It is provided with a drainage device 23 for removing water droplets on the surface of the film. Further, it includes a biaxial stretching machine 29 that biaxially stretches the film 18 after the draining treatment in the vertical and horizontal directions, and a recovery roller 30 that winds up the film 18 formed by the biaxial stretching machine 29.

The lateral stretching mechanism 40 shown in FIG. 5 is provided as a component of the biaxial stretching machine 29. The lateral stretching mechanism 40 is provided with a tenta clip 31. The lateral stretching mechanism 40 is arranged on both the left and right sides of the film 18 to be sent, and the guide rails 33 and 34 and the guide rails 33 and 34 in which the distance between the guides gradually widens in the traveling direction of the line are gradually widened. A plurality of tenta clips 31 that circulate on the line in the traveling direction are provided.

The tenta clip 31 has a grip portion 32 that grips the end portion of the film 18, and guide bearings 35 and 36 that roll on the guide rails 33 and 34 composed of closed loops. The tenta clip 31 plays a role of extending the film 18 in the lateral direction by advancing in the traveling direction along the guide rails 33 and 34 in a state where both ends of the film 18 are gripped by the grip portion 32. There are two types of guide rails 33 and 34: a guide rail 33 whose guide surface is directed in the horizontal direction and a guide rail 34 whose guide surface is directed in the vertical direction. The guide bearings 35, 36 of the tenta clip 31 play a role of rolling and guiding the tenta clip 31 along the guide rails 33, 34, respectively. Of the guide bearings 35 and 36, the guide bearing 35 that rolls on the guide surface in the horizontal direction is installed on the fixed shaft 37 in the horizontal direction (horizontal posture). The guide bearing 36 that rolls on the guide surface in the vertical direction is installed on the fixed shaft 38 in the vertical direction (vertical posture). As the guide bearing attached to the fixed shaft 38 in the vertical posture, the deep groove ball bearing according to the present invention shown in FIG. 1 is used.

By the way, since a large amount of guide roller bearings are used in the film stretching machine, a non-contact type sealing plate 5 having a small rotational torque is used for the deep groove ball bearing of the present invention used as the guide roller bearing. As a result, the power consumption of the entire facility can be suppressed, but even if a so-called contact seal is used, in which there is no labyrinth seal gap (g) between the inner diameter side end of the sealing plate 5 and the sealing groove 9 of the inner ring 1. Good.

Further, by making the inner diameter of the cage 4 a single circular shape, the deep groove ball bearing of the present invention can be applied to the guide roller of the film stretching machine tenta clip without increasing the cost as compared with the conventional bearing. it can. The plate thickness of the cage 4 may be arbitrarily selected according to the material and strength. Further, as the material of the cage 4, cold rolled steel or stainless steel can be selected, and nitriding treatment may be performed if necessary.

As the material of the ball 3, ceramic may be used in addition to steel. Further, as the grease to be sealed in the bearing, a grease in which the base oil is fluorine oil and the thickener is PTFE or boron nitride can be selected.

The present invention is not limited to the above-described embodiments, and it goes without saying that the present invention can be carried out in various forms without departing from the gist of the present invention, and the scope of the present invention is claimed. Indicated by the scope of, and further include the equal meaning described in the claims, and all modifications within the scope.

1: Inner ring 1a: Track surface 1b: Inner ring outer diameter surface 2: Outer ring 2a: Track surface 3: Ball 4: Cage 4a: Cage inner diameter surface 5: Sealing plate 16: Film stretching machine 31: Tenta clip Dw: Diameter ei : Radial gap

Claims (3)

The outer ring (2), the inner ring (1), the plurality of balls (3) assembled between the outer ring raceway surface (2a) and the inner ring raceway surface (1a), and the balls (3) are the inner ring (1). A cage (4) that holds the outer ring (2) evenly in the circumferential direction on the raceway surface, and an axial end of the inner ring (1) that is fixed to the axial end of the outer ring (2) and a gap (g). A deep groove ball bearing composed of at least one sealing plate (5) having a paddle wheel.
The cage (4) is a waveform cage in which two ring parts are combined.
The relationship between the radial gap ei between the inner diameter surface (4a) of the cage and the outer diameter surface (1b) of the inner ring and the diameter Dw of the ball (3) is
0.11 x Dw ≤ ei <0.35 x Dw
A deep groove ball bearing characterized by being. The deep groove ball bearing according to claim 1, which is used for outer ring rotation. The deep groove ball bearing according to claim 1 or 2, which is used for a guide roller of a film stretching machine tenta clip.

Images