KR20200083784A - Tandem Ball Bearing - Google Patents

Abstract

The present invention relates to a tandem ball bearing. The tandem ball bearing according to one embodiment of the present invention includes: an inner ring wherein the inner raceway surface of a rolling element is formed on the outer circumferential surface; an outer ring which is mounted radially outside the inner ring and in which the outer raceway surface of the rolling element is formed on the inner peripheral surface; the rolling element mounted between the inner ring and the outer ring; and a cage receiving and supporting the rolling element. When assembling a bearing, an end portion of the outer ring positioned at the side into which the rolling element is inserted may be configured to have a stepped unit partially surrounding the inserted rolling element and a step unit having a larger diameter than that of the stepped unit. An object of the present invention is to provide the tandem ball bearing which can be manufactured with higher productivity.

Description

Tandem Ball Bearing {Tandem Ball Bearing}

The present invention relates to a bearing used to rotatably mount and support a rotating element on a non-rotating element in a rotating device, and more specifically, by forming a stepped portion at the end of the outer ring to increase the outlet side area through which the lubricant flows, thereby It relates to a tandem ball bearing configured to improve fluidity and allow easier manufacturing.

A bearing is a device that is mounted between a rotating element and a non-rotating element in a rotating device to assist relative motion between a rotating element and a non-rotating element, and can be divided into a sliding bearing and a rolling bearing according to the way the bearing and the shaft contact. .

Of these, rolling bearings are bearings that support a rotating shaft using rolling elements such as balls or rollers. They have advantages of smaller frictional resistance than sliding bearings that directly contact a part of the shaft and are used in various fields. It is used in the form of ball bearings, tapered roller bearings, needle bearings, etc. according to the shape of the rolling element.

Among the rolling bearings, tapered roller bearings have a tapered conical structure and have a rolling element, which has a relatively high axial and radial load bearing force, and has been widely used to support a rotating shaft of a power transmission device. However, since the tapered roller bearing is operated in a state in which the rolling elements are in linear contact with the inner and outer rings, the load-bearing ability is good, but the frictional resistance torque is high, resulting in a large power transmission loss.

To solve this problem, recently, the use of tandem type ball bearings having a relatively small bearing capacity but less power transmission loss (friction resistance torque) than tapered roller bearings has increased.

Referring to FIG. 1, the structure of a tandem ball bearing 10 conventionally used is illustrated. As shown in Figure 1, the tandem ball bearing 10 is placed between the inner ring 20 and the outer ring 30 and the inner ring 20 and the outer ring 30, which is press-fitted and mounted on the housing, etc. It is composed of a ball rolling element 40, and the ball rolling element 40 may be formed by being arranged in a double row in a spaced apart state along the axial direction.

However, the tandem ball bearing 10 shown in FIG. 1 has a stepped portion 32 at the end of the outer ring 30 so that the rolling element 40 is mounted between the inner ring 20 and the outer ring 30 to be stably maintained. ) Is formed so as to partially cover the rolling element 40, the discharge of the lubricant is interfered by the stepped portion 32 of the outer ring 30, and the lubricant does not flow smoothly, and thus the life of the bearing is reduced. There is a shortening problem.

As a method for solving this problem, as shown in FIG. 2, a method of improving the fluidity of the lubricating oil may be considered by shortly forming the end portion of the outer ring 30 to remove the stepped portion.

However, in the case of a bearing having such a structure, as shown in FIG. 3, when assembling the bearing, the assembly tool 60 first contacts the rolling element cage 50 before contacting the outer ring 30, so that the assembly process is disturbed. Problems can occur.

Korean Patent Publication No. 10-2017-0013666 (Publication date: 2017.02.07.)

The present invention is to solve the above-mentioned problems occurring in the conventional tandem ball bearing, it is possible to provide a smooth flow of lubricant at the same time without lowering the assembly of the bearing, and furthermore, a tandem ball bearing that can be manufactured with higher productivity It aims to provide.

A representative configuration of the present invention for achieving the above object is as follows.

The tandem ball bearing according to an embodiment of the present invention includes an inner ring having an inner raceway surface of the rolling element formed on an outer circumferential surface, an outer ring having an outer raceway surface of an rolling element formed on an inner circumferential surface, and between an inner ring and an outer ring. It may be configured to include a rolling element that is mounted on, and a cage for receiving and supporting the rolling element, and when assembling the bearing, a stepped portion and a stepped portion partially surrounding the inserted rolling element at the end of the outer ring positioned at the side where the rolling element is inserted. It may be configured to be provided with a stepped portion having a larger diameter.

According to an embodiment of the present invention, the connecting portion between the stepped portion and the stepped portion may be configured to include a plurality of inclined surfaces having different inclination angles.

According to an embodiment of the present invention, the connecting portion between the stepped portion and the stepped portion has a first inclined angle with respect to the central axis, a first inclined surface located at the stepped portion and a second inclined angle with respect to the central axis, and a stepped portion. A second inclined surface is included, and the second inclined angle may be formed at an angle greater than the first inclined angle.

According to an embodiment of the present invention, the first inclination angle may be formed at an angle of 20° to 55°.

According to an embodiment of the present invention, the second inclination angle may be formed at an angle greater than 5° to 20° than the first inclination angle.

According to an embodiment of the present invention, the radial distance between the point at which the first inclined surface and the second inclined surface intersect and the stepped portion may be formed to a value of 4% to 10% of the diameter of the rolling element disposed adjacent to the stepped portion. Can.

According to an embodiment of the present invention, the radial distance between the stepped portion and the stepped portion may be formed to a value of 1.5 to 2.5 times the radial distance between the point at which the first and second sloped surfaces intersect and the stepped portion. have.

According to an embodiment of the present invention, the outer ring may extend outwardly in the axial direction than the cage for receiving and supporting the rolling element and the rolling element.

In addition to this, the tandem ball bearing according to the present invention may further include other additional configurations without detracting from the technical spirit of the present invention.

The tandem ball bearing according to an embodiment of the present invention is configured to form a stepped portion having a larger diameter than the stepped portion at the end of the outer ring, so that the lubricant can be discharged more easily, and the fluidity of the lubricant can be increased. Collision between the lubricating oil and the remaining lubricating oil is minimized so that the stirring resistance is reduced and the frictional resistance torque can be reduced.

In addition, the tandem ball bearing according to an embodiment of the present invention is configured such that the connecting portion between the stepped portion formed on the outer side of the stepped portion and the stepped portion of the outer ring includes a plurality of straight surfaces having different inclination angles, and the rolling elements are inserted. The part to be mounted can be more easily polished, which makes it possible to manufacture the outer ring and bearings containing it with higher productivity.

1 exemplarily shows a structure of a tandem ball bearing used in the related art.
2 exemplarily shows a tandem ball bearing of another structure used in the related art.
3 exemplarily shows a state in which the tandem ball bearing shown in FIG. 2 is assembled.
4 exemplarily shows the structure of a tandem ball bearing according to an embodiment of the present invention.
5 is an enlarged view showing a stepped portion, a stepped portion, and a connection portion therebetween provided on an outer ring of a tandem ball bearing according to an embodiment of the present invention.
6 exemplarily shows a state of performing a polishing process in a structure in which a connecting portion between a stepped portion and a stepped portion of an outer ring is formed as one inclined surface.
7 exemplarily shows a state of performing a polishing process in a structure in which a connecting portion between a stepped portion and a stepped portion of an outer ring is formed to include a plurality of straight surfaces having different inclination angles.
8 exemplarily shows a state in which the rolling element (ball) is inserted into the outer ring in the tandem ball bearing according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art to which the present invention pertains can easily implement them.

In order to clearly describe the present invention, detailed descriptions of parts not related to the present invention are omitted, and the same reference numerals are given to the same components throughout the specification. In addition, since the shapes and sizes of each component illustrated in the drawings are arbitrarily shown for convenience of description, the present invention is not necessarily limited to the illustrated shapes and sizes. That is, specific shapes, structures, and characteristics described in the specification may be implemented by changing from one embodiment to another embodiment without departing from the spirit and scope of the present invention, and the position or arrangement of individual components is also the spirit of the present invention. And it should be understood that it can be changed without departing from the scope. Therefore, the detailed description to be described later is not made in a limiting sense, and the scope of the present invention should be taken to cover the scope claimed by the claims of the claims and all equivalents thereto.

Preferred embodiments of the invention

4 and 5, the tandem ball bearing 100 according to an embodiment of the present invention is illustrated by way of example. As shown in the figure, the tandem ball bearing 100 according to an embodiment of the present invention is similar to a conventional tandem ball bearing radially spaced in the radially spaced inner ring 200 and outer ring 300 and between them It may be configured to include a rolling element 400 is disposed.

Specifically, the tandem ball bearing 100 according to an embodiment of the present invention is mounted on the inner circumferential surface of the inner raceway 200, the inner raceway surface of which the rolling element is formed on the outer circumferential surface, and the inner circumferential surface of the rolling element on the inner circumferential surface. It is composed of an outer raceway (300) having an outer raceway surface, a rolling body (400) seated between the inner raceway (200) and an outer raceway (300), and a cage (500) for receiving and supporting the rolling body (400). Can be.

The inner ring 200 is configured to be press-fitted to the outer circumferential surface of the rotating shaft and the like, and may be configured to support the rolling element 400 from the inside through a raceway surface (inner raceway surface 210) formed on the outer circumferential surface. In the case of the embodiment shown in the drawing, two inner raceway surfaces (first inner raceway surface 210a and second) are provided on the outer circumferential surface of the inner ring 200 to support the two rows of rolling elements 400 spaced apart in the axial direction. 2 inner raceway surface 210b].

The outer ring 300 is mounted on the radially outer side of the inner ring 200 to be press-fitted into a housing or the like, and to support the rolling element 400 from the outside through a raceway surface (outer raceway surface 310) formed on the inner circumferential surface. Can be configured. In the case of the embodiment shown in the drawing, two outer raceways (first outer raceway 310a) and two outer raceways on the inner circumferential surface of the outer ring 300 to support the two rows of rolling elements 400 spaced apart in the axial direction. 2 outer raceway surface 310b].

The rolling element 400 is disposed at predetermined intervals in a state accommodated in the cage 500 between the inner raceway surface 210 formed on the inner ring 200 and the outer raceway surface 310 formed on the outer ring 300, and is disposed at a predetermined interval. ) And performs the function of providing relative motion between the outer ring (300). The rolling elements 400 may be arranged in a plurality at predetermined intervals along the circumferential direction based on the rotation axis of the bearing, and may be arranged in one row along the axial direction or in double rows of two or more rows. For example, in the case of the embodiment shown in the drawings, the bearing is configured in the form of a tandem ball bearing in which a ball-shaped rolling element is disposed in two rows (first row and second row) spaced apart in the axial direction.

On the other hand, when the rolling elements are arranged in a double row as shown in the drawing, the pitch circle diameter of the rolling elements arranged in the first row and the pitch circle diameter of the rolling elements arranged in the second row may be the same or differently formed. , When the pitch circle diameters of the rolling elements arranged in the first row and the rolling elements arranged in the second row are formed differently, as shown in the embodiment shown in the drawing, the lubricant can flow more smoothly inside the bearings, thereby operating performance of the bearing. And lifespan can be improved.

According to an embodiment of the present invention, a locking jaw 320 extending radially inward is provided near one end of the outer ring 300 (in the case of the structure shown in FIG. 4, the left end of the drawing), the inner ring 200 ) And the rolling element 400 inserted between the outer ring 300 may be configured to prevent departure from the outside, one end of the inner ring 200 (in the case of the structure shown in FIG. 4, the right end of the drawing) A support jaw 220 is provided in the vicinity, and may be configured to prevent the rolling element 400 inserted between the inner ring 200 and the outer ring 300 from escaping to the outside.

According to an embodiment of the present invention, the outer ring 300 may be configured to extend outwardly in the axial direction than the rolling element 400 and the cage 500 supporting the rolling element 400 located therein. . As described above, when the outer ring 300 is formed to protrude to the outer axial direction than the rolling element 400 and the cage 500 supporting the rolling element, the assembly tool is used when assembling the bearing, unlike the conventional tandem ball bearing described in FIG. 2 above. It can be prevented from interfering with the cage and the like to interfere with assembly.

However, when the outer ring 300 is elongated in the axial direction as described above, the flow of the lubricant is impeded by the stepped portion formed in the outer ring similar to the conventional tandem ball bearing described in FIG. 1, thus lowering the fluidity of the lubricant. Due to this, there may be a problem that performance and life of the bearing are deteriorated.

In order to prevent such a problem, the tandem ball bearing 100 according to an embodiment of the present invention has one end of the outer ring 300 (the end located on the side where the rolling element 400 is inserted during bearing assembly: illustrated in FIG. 4) In the case of the structure, the stepped portion 340 having a larger diameter than the stepped portion 330 may be formed at the right end of the drawing to improve the fluidity of the lubricant by the stepped portion 340 of the expanded diameter.

Specifically, the tandem ball bearing 100 according to an embodiment of the present invention is inserted between the inner ring 200 and the outer ring 300 at one end of the outer ring 300, as shown in Figures 4 and 5 It has a stepped portion 330 configured to partially surround the fuselage 400, and is configured to have a stepped portion 340 having a larger diameter than the stepped portion 330 from the stepped portion 330 in the axial outer side. have.

As such, the tandem ball bearing 100 according to an embodiment of the present invention has a stepped portion 340 having a larger diameter than the stepped portion 330 at one end of the outer ring 300, and thus has a narrow diameter. While moving to the stepped portion 340 having a wider diameter through the stepped portion 330, the fluidity of the lubricating oil is improved, so that a smooth flow of the lubricating oil can be formed.

However, when forming a structure of an additional shape such as a stepped portion 340 at the end of the outer ring 300 positioned on the side where the rolling element 400 is inserted, a portion to be polished during manufacturing of the outer ring 300 There is a concern that productivity may be reduced and manufacturing costs may increase due to widening.

To solve this problem of productivity reduction, the tandem ball bearing 100 according to an embodiment of the present invention has a special structure at one end portion of the outer ring 300 where the stepped portion 330 and the stepped portion 340 are formed. It can be configured to prevent a decrease in productivity of the outer ring by applying a shape profile.

Specifically, in the tandem ball bearing 100 according to an embodiment of the present invention, the connecting portion 350 between the stepped portion 330 and the stepped portion 340 formed at one end of the outer ring 300 has different inclination angles. It may be configured to be formed in a structure including a plurality of inclined surfaces (first inclined surface 360 and second inclined surface 370).

For example, in the tandem ball bearing 100 according to an embodiment of the present invention, the connection portion 350 between the stepped portion 330 and the stepped portion 340 formed at one end of the outer ring 300 is provided relative to the central axis. It is configured to include a first inclined surface (360) having a first inclination angle (α) and a second inclined surface (370) having a second inclined angle (β) with respect to the central axis, the second inclined angle (β) is a first inclined angle ( It is configured to be formed at an angle greater than α). As described above, when the connecting portion 350 between the stepped portion 330 and the stepped portion 340 is configured to include the inclined surfaces having different inclination angles, polishing processing should be performed at the time of manufacturing the outer ring 300 as described later. The portion to be reduced or the difficulty of the polishing process can be reduced, thereby improving the productivity of the outer ring 300 and reducing the manufacturing cost.

For example, when manufacturing the outer diameter of the bearing, it is possible to damage the rolling element during the assembly and operation of the bearing by performing abrasive processing on the part where the rolling element is assembled and seated (orbital surface) and the portion where the rolling element can be contacted during assembly. Should be configured to prevent.

However, when the connecting portion 350 between the stepped portion 330 and the stepped portion 340 formed at one end of the outer ring 300 is formed as a single inclined surface structure, the connecting portion 350 is not intended to be polished during the polishing process. A step is formed (a step is formed at a boundary between a part where the abrasive grindstone 600 contacts and a part not contacting as shown in FIG. 6(a)), and the step formed when the rolling element is inserted into the bearing. There is a risk that the rolling element is damaged due to the occurrence of a stamping on the rolling element by the edge 350a.

In order to prevent such a problem, a method of polishing the entire end region of the outer ring 300 including the stepped portion 330 and the stepped portion 340 may be considered (see FIG. 6B ), but in this case Since it is necessary to perform a polishing process requiring a very long process time over a wide range, the manufacturing time and manufacturing cost of the bearing are increased, and further, the tool cost of the abrasive grit 600 is greatly increased, thereby increasing the overall manufacturing cost. .

On the other hand, the tandem ball bearing 100 according to an embodiment of the present invention has a different inclination angle to the connecting portion 350 between the stepped portion 330 and the stepped portion 340 formed at the end of the outer ring 300 Since the plurality of inclined surfaces (the first inclined surface 360 and the second inclined surface 370) is configured to be included, the above-described problem can be prevented.

Specifically, the tandem ball bearing 100 according to an embodiment of the present invention is a polishing process even if the second inclined surface 370 is polished only to an area including the first inclined surface 360 as shown in FIG. 7 Since it is not involved in, it is possible to prevent an unintended step in the polishing process or an increase in the processing load of the polishing process.

According to an embodiment of the present invention, the first inclined surface 360 located on the side of the stepped portion 330 in the connection portion 350 between the stepped portion 330 and the stepped portion 340 is a bearing for forming a smooth inclined surface It may be formed of an inclination angle [first inclination angle (α)] of 20 ° to 55 ° with respect to the axis of rotation, the second inclined surface 370 is 5 ° to 20 ° greater inclination angle than the first inclined surface 360 [product 2 inclination angle (β)].

On the other hand, according to one embodiment of the present invention, the first inclined surface 360 and the second inclined surface 370 intersect the portion A (that is, the first inclined surface 360 is switched to the second inclined surface 370) Beginning part] and the radial distance H1 between the stepped parts 330 may be formed to have a value of 4% to 10% of the diameter of the rolling element disposed adjacent to the stepped parts 330. If, the radial distance (H1) from the stepped portion 330 to the portion (A) where the first inclined surface 360 and the second inclined surface 370 intersect the rolling element disposed adjacent to the stepped portion 330 If it is formed to be less than 4% of the diameter, there is a fear that the rolling element is in contact with the intersection point A of the first inclined surface 360 and the second inclined surface 370 in the process of inserting the rolling element (see FIG. 8 ). ). In addition, the radial distance H1 from the stepped portion 330 to the portion A where the first inclined surface 360 and the second inclined surface 370 intersect is adjacent to the stepped portion 330. If it is formed in excess of 10% of the diameter, there is a fear that the area requiring abrasive processing is widened, thereby increasing bearing manufacturing time and manufacturing cost. On the other hand, the tandem ball bearing 100 according to an embodiment of the present invention is the radial distance between the portion (A) and the stepped portion 330 where the first inclined surface 360 and the second inclined surface 370 intersect ( Since H1) is controlled within a predetermined range, it is possible to effectively manufacture and at the same time to compensate for the risk of damaging the rolling elements in the bearing assembly process.

In addition, according to an embodiment of the present invention, the radial distance H2 from the stepped portion 330 to the stepped portion 340 is guided by the polishing surface to be assembled, the inner ring 200 and the outer ring 300 ) 1.5 times to the radial distance H1 from the stepped portion 330 to the portion A where the first inclined surface 360 and the second inclined surface 370 intersect to be stably provided as an assembly position between) It may be desirable to form 2.5 times.

Although the present invention has been described above by means of specific matters such as specific components and limited embodiments, these embodiments are provided to help the overall understanding of the present invention, but the present invention is not limited thereto, and the present invention Those skilled in the art can make various modifications and variations from these descriptions.

Therefore, the spirit of the present invention is not limited to the above-described embodiments, and should not be determined, and all claims that are equally or equivalently modified in the claims as described below belong to the scope of the spirit of the present invention. something to do.

100: tandem ball bearing
200: inner ring
210: inner raceway surface
220: support jaw
300: paddle
310: outer raceway surface
320: hanging jaw
330: step
340: step
350: connection
360: first slope
370: second slope
400: rolling element
500: cage
600: grinding stone
α: first inclination angle (inclination angle between the first inclined surface and the central axis)
β: second inclination angle (inclination angle between the second inclined surface and the central axis)
H1: Radial distance from the stepped section to the intersection (A) of the first and second slopes
H2: Radial distance from stepped to stepped

Claims (8)

An inner ring 200 having an inner raceway surface of a rolling element formed on an outer peripheral surface,
The outer ring 300 is mounted on the radially outer side of the inner ring 200 and the outer raceway surface of the rolling element is formed on the inner circumferential surface.
The rolling element 400 is mounted between the inner ring 200 and the outer ring 300,
It includes a cage 500 for receiving and supporting the rolling element 400,
At the end of the outer ring 300 positioned on the side where the rolling element 400 is inserted when assembling the bearing, the stepped portion 330 partially surrounding the inserted rolling element 400 and the step having a larger diameter than the stepped portion 330 Part 340 is provided,
Tandem ball bearing. According to claim 1,
The connecting portion 350 between the stepped portion 330 and the stepped portion 340 includes a plurality of inclined surfaces having different inclination angles,
Tandem ball bearing. According to claim 2,
The connecting portion 350 between the stepped portion 330 and the stepped portion 340 has a first inclination angle α with respect to the central axis, and the first inclined surface 360 and the central axis located on the stepped portion 330 side. A second inclined surface 370 having a second inclination angle β with respect to the stepped portion 340 is included,
The second inclination angle (β) is formed at an angle greater than the first inclination angle (α),
Tandem ball bearing. According to claim 3,
The first inclination angle (α) is formed at an angle of 20 ° to 55 °,
Tandem ball bearing. According to claim 4,
The second inclination angle β is formed at an angle greater than 5° to 20° than the first inclination angle α,
Tandem ball bearing. The method of claim 5,
The radial distance H1 between the point A at which the first inclined surface 360 and the second inclined surface 370 intersect and the stepped portion 330 is disposed adjacent to the stepped portion 330. Formed with a value of 4% to 10% of the diameter of the fuselage 400,
Tandem ball bearing. The method of claim 5,
The radial distance H2 between the stepped portion 330 and the stepped portion 340 is a point A at which the first inclined surface 360 and the second inclined surface 370 intersect and the stepped portion 330 ) Is formed with a value of 1.5 to 2.5 times the radial distance (H1) between,
Tandem ball bearing. The method according to any one of claims 1 to 7,
The outer ring 300 extends outwardly in the axial direction than the cage 500 that receives and supports the rolling element 400 and the rolling element 400, and protrudes outward.
Tandem ball bearing.

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