WO2015104943A1

WO2015104943A1 - Rolling bearing

Info

Publication number: WO2015104943A1
Application number: PCT/JP2014/082734
Authority: WO
Inventors: 庸児堀井; 政幸伊藤; 剛奥永
Original assignee: 日本精工株式会社
Priority date: 2014-01-07
Filing date: 2014-12-10
Publication date: 2015-07-16
Also published as: AU2016100959A4; JP2015129547A; CN206072111U; DE212014000240U1; JP6307883B2

Abstract

A rolling bearing (100) comprising: an outer ring (1); an inner ring (6); and a holder (10) that holds each of a plurality of cylindrical rollers (9) inserted between the outer ring (1) and the inner ring (6), by using a plurality of pockets (14) provided at even intervals in the circumferential direction. The inner circumferential surface of the holder (10) has a notched section (15) formed therein. The bearing internal dimension ratio (α), indicated by formula (1) is 1.4 ≤ α ≤ 2.1, said formula using the radial direction dimension (h) of the notched section (15), the inside diameter dimension (D₁) of the outer ring, the outside diameter dimension (D₂) of the holder (10), the pitch circle diameter (dm) of the rolling bearing (100), the number (z) of cylindrical rollers (9), the outer diameter dimension (Da) of the cylindrical rollers (9), and the axial direction dimension (L) of the cylindrical rollers (9).

Description

Rolling bearing

The present invention relates to a rolling bearing.

Rolling bearings generate heat due to rolling resistance caused by rotation of rolling elements and races, slip resistance on the guide surface of the cage, and agitation resistance of lubricating oil. Among these, the stirring resistance is a resistance generated when the rolling elements scrape the lubricating oil present inside the bearing. In particular, in a rolling bearing in which oil bath lubrication is performed, a large proportion of heat is generated due to the stirring resistance of the lubricating oil.

On the other hand, the lubricating oil also has a cooling action. A rolling bearing in which oil lubrication for forcibly circulating the lubricating oil is performed is cooled by heat exchange when the lubricating oil supplied passes through the inside of the bearing. The effect of this cooling is determined according to the speed of the oil when the lubricating oil passes through the inside of the bearing, the amount of oil supply, and the like. Furthermore, the bearing in which oil bath lubrication is performed is cooled by heat exchange between the stagnant lubricating oil and the bearing. The effect of this cooling is determined according to the oil flow (circulation) inside the bearing and the amount of lubricating oil. In any lubrication method, the cooling effect is determined by the balance with heat generation.

Here, let us consider heat generation in a so-called NU type cylindrical roller bearing in which flanges are provided at both ends in the axial direction of the outer ring. Since the outer ring provided with the collar accumulates lubricating oil inside, when the revolving rolling element passes, the lubricating oil must be scraped, the stirring resistance increases, and heat is generated. Therefore, conventionally, a method has been proposed in which heat generation is reduced by not storing lubricating oil inside the bearing (see, for example, Patent Document 1).

In the cylindrical roller bearing device disclosed in Patent Document 1, the radial dimensions of both axial ends of rotating members such as a cage and a race ring are made different, and a communication passage communicating with an oil sump is formed in the housing. Yes. Lubricating oil can be transported in the axial direction depending on the magnitude of the centrifugal force by providing a difference in the radial dimension at both axial ends of the rotating member. Therefore, heat exchange between the bearing and the lubricating oil is promoted by circulation of the lubricating oil in the axial direction, and a cooling effect can be expected.

Japanese Unexamined Patent Publication No. 11-230178

However, in the configuration of Patent Document 1, the structure of the housing is complicated and large-scale, and the shape of the rotating member such as the cage or the raceway is also complicated, so that the manufacturing cost increases and the assemblability decreases. There is also a problem.

The present invention has been made in view of such problems, and an object of the present invention is to provide a rolling bearing with improved cooling capacity without increasing the manufacturing cost.

In order to achieve the above object, the present invention has the following features.
[1] Outer ring,
Inner ring,
A cage for holding a plurality of rolling elements incorporated between the outer ring and the inner ring in a plurality of pockets provided at equal intervals in the circumferential direction;
A rolling bearing comprising:
A notch is formed on the inner peripheral surface of the cage,
Radial dimension h of the notch, the inner diameter D ₁ of the outer _ring, the outer diameter D ₂ of the _retainer, the bearing pitch circle diameter dm, the number z of the rolling element, the outer diameter Da of the rolling element, A rolling bearing according to claim 1, wherein a bearing internal dimension ratio α represented by the formula (1) satisfies 1.4 ≦ α ≦ 2.1 by the axial dimension L of the rolling element.

[2] The rolling bearing according to [1], which is used in oil lubrication.
[3] The rolling bearing according to [2], wherein the oil lubrication is selected from jet lubrication, oil-air lubrication, splash lubrication, and oil bath lubrication.

According to the present invention, it is possible to provide a rolling bearing with improved cooling capacity without increasing manufacturing costs.

It is sectional drawing of the rolling bearing which concerns on 1st Embodiment of this invention. It is a side view of the rolling bearing of FIG. It is a perspective view of the holder | retainer of the rolling bearing of FIG. It is a figure for demonstrating circulation of the lubricating oil inside the rolling bearing of FIG. It is a figure for demonstrating the heat_generation | fever and cooling mechanism inside a rolling bearing. It is a figure for demonstrating Bernoulli's theorem. It is a figure for demonstrating the structure of the test bearing which performs circulating oil supply. It is a graph which shows an experimental result. It is a graph which shows an experimental result. It is sectional drawing of the rolling bearing which concerns on the modification of 1st Embodiment of this invention. It is a perspective view of the holder | retainer of the rolling bearing of FIG. It is a figure for demonstrating the shape of the notch part of a cage | basket in the rolling bearing which concerns on 2nd Embodiment of this invention. It is a perspective view of the holder | retainer of the rolling bearing of FIG. It is a side view of the rolling bearing which concerns on 3rd Embodiment of this invention. It is a perspective view of the holder | retainer of the rolling bearing of FIG.

(First embodiment)
Hereinafter, a first embodiment of a rolling bearing of the present invention will be described with reference to the drawings. FIG. 1 is a sectional view of a rolling bearing 100 according to the first embodiment of the present invention, FIG. 2 is a side view of the rolling bearing 100, FIG. 3 is a perspective view of a cage 10 of the rolling bearing 100, and FIG. FIG. 4 is a diagram for explaining the circulation of lubricating oil inside the bearing 100.

The rolling bearing 100 includes a plurality of cylindrical rollers 9 (rolling elements) between an outer ring raceway surface 2 formed on the inner peripheral surface of the outer ring 1 and an inner ring raceway surface 7 formed on the outer peripheral surface of the inner ring 6. . The rolling bearing 100 is a cylindrical roller bearing generally called an NU type in which collars 3 are formed at both axial ends of the outer ring 1. The rolling bearing 100 is used under oil lubrication.

The cage 10 includes a pair of

annular portions

11 and 12 arranged side by side in the axial direction, a plurality of column portions 13 that connect the pair of

annular portions

11 and 12 in the axial direction, and a pair of annular portions 11. , 12 and the column part 13, and a plurality of pockets 14 for accommodating the cylindrical rollers 9 one by one. In this way, the cage 10 holds the plurality of cylindrical rollers 9 (rolling elements) in the plurality of pockets 14 provided at equal intervals in the circumferential direction.

The outer peripheral surface of the cage 10 is a straight line in the axial direction. A notch portion 15 is formed on the inner peripheral surface of the column portion 13 of the cage 10. The notch 15 is formed to have a rectangular cross section.

The mechanism of heat generation and cooling inside the rolling bearing 100 will be described in detail with reference to FIGS. As shown in FIG. 4, when the lubricating oil flows into the rolling bearing 100, the lubricating oil accumulates in the notch portion 15 provided on the inner peripheral surface of the cage 10. The lubricating oil accumulated in the notch 15 is subjected to a pressure for pushing out the lubricating oil by the centrifugal force accompanying the rotation of the cage 10. This pressure and centrifugal force overcome the flow resistance in the gap between the pocket 14 of the cage 10 and the cylindrical roller 9, so that the lubricating oil flows into the pocket 14. In the pocket 14, heat is generated due to the stirring resistance.

Furthermore, the lubricating oil passes through the pocket 14 by the pressure and centrifugal force described above, flows out to the outer peripheral surface of the cage 10, and further flows out to the outer ring raceway surface 2. The outer ring raceway surface 2 also generates heat due to the stirring resistance. Thus, the lubricating oil that has flowed out to the outer peripheral surface of the cage 10 and the outer ring raceway surface 2 pushes out the lubricating oil accumulated between them one after another. This pressure overcomes the flow resistance in the gap between the outer peripheral surface of the rotating cage 10 and the inner peripheral surface of the outer ring 1 that is a stationary wheel, whereby the lubricating oil is discharged (outflowed) to the outside of the bearing. Is done.

Thus, the flow of the lubricating oil passing through the rolling bearing 100 causes heat exchange between the rolling bearing 100 and the lubricating oil, and the rolling bearing 100 is cooled. Further, the amount of the lubricating oil accumulated in the rolling bearing 100 acts on both cooling and stirring resistance. Therefore, the inflow amount of the lubricating oil, the amount of the lubricating oil accumulated in the rolling bearing 100, and the outflow amount of the lubricating oil greatly affect the bearing temperature. Therefore, in order to obtain a sufficient temperature reduction effect, it is desirable that the inflow amount and the outflow amount of the lubricating oil are balanced.

Here, the gap between the outer peripheral surface of the cage 10 and the inner peripheral surface of the outer ring 1 (inner peripheral surface of the collar 3) acts as a throttle that adjusts the amount of lubricating oil discharged. In addition, the size of the notch 15 of the cage 10 affects the amount of lubricating oil flowing into the rolling bearing 100. Therefore, in the present embodiment, not only the notch 15 is formed on the inner peripheral surface of the cage 10, but also the radial dimension of the notch 15 (hereinafter also referred to as a notch amount) and the inner periphery of the outer ring 1. The bearing temperature reduction can be improved by appropriately setting the dimension of the gap between the surface and the outer peripheral surface of the cage 10 and other combined parameters.

First, the inflow of lubricating oil and _{Q in,} the outflow amount is _{Q out,} think about the balance of the conditions of inflow _{Q in} the runoff _{_{_{Q out (Q in = Q out}}} ). Inflow Q _in the flow velocity v of the lubricating oil by centrifugal force, and the cross-sectional area A _in the inlet, by expressed as follows.

The centrifugal force acting on the lubricating oil accumulated in the notch 15 is represented by the centrifugal force acting on the pitch circle diameter dm of the rolling bearing 100. The flow velocity v of the lubricating oil due to the centrifugal force is expressed by the energy equation using the pitch circle diameter dm of the rolling bearing 100, the revolution speed ω of the cage 10, the notch amount h of the notch 15 and the mass m of the lubricating oil. It is expressed as follows.

Further, the cross-sectional area A _in the inlet portion, the outer diameter Da of the cylindrical rollers 9, the length of the cylindrical roller 9 (axial dimension) L, with the number z of the cylindrical rollers 9, be expressed as follows it can.

Here, when the length L of the cylindrical roller 9 is equal to the length (axial dimension) Lp of the pocket 14 (L = Lp), the cross-sectional area S _in of the notch 15, the notch amount h, and The length L of the cylindrical roller 9 satisfies the following relationship.

The outflow amount Q _out is limited by the throttling effect due to the gap between the outer peripheral surface of the cage 10 and the inner peripheral surface of the outer ring 1 and the resistance due to rotation. Thus, runoff _{Q out} is the cross-sectional area _{S out} of the outlet portion, the lubricating oil of the head (liquid level) H (see FIG. 6), the oil discharge resistor R, with a coefficient B, represented as follows The

Further, the cross-sectional area S _out of the outflow portion is expressed as follows using the inner diameter D ₁ of the outer ring 1 (the inner diameter of the collar 3) D ₁ , the outer diameter D _{2 of} the cage 10, and the pitch circle diameter dm of the rolling bearing 100. Can be represented.

Also, the oil drain resistance R can be expressed as follows.

Here, as described above, in order to obtain a sufficient temperature reduction effect, the inflow amount Q _in and the outflow amount Q _out need to be equally balanced (Q _in = Q _out ). It can be transformed as follows.

When the above formula is expressed by head H, it can be transformed as follows.

In this embodiment, as representative of the size effect of the rolling bearing 100, the head H is divided by the pitch circle diameter dm of the rolling bearing 100, and this value is defined as the bearing internal dimension ratio α.

(Experiment)
Using the test structure shown in FIG. 7, a rolling test was performed by incorporating the rolling bearing 100 into the shaft S. The rotation test was performed by changing the bearing internal dimension ratio α of the rolling bearing 100 and using two rotation speeds n and m. FIG. 8 is a graph showing the results of this rotation test, and shows the relationship between the bearing internal dimension ratio α and the temperature reduction effect in the rolling bearing 100. FIG. 8 shows that even if the rotational speed is changed to n and m, a sufficient temperature reduction effect can be obtained when the bearing internal dimension ratio α satisfies 1.4 ≦ α ≦ 2.1. .

For comparison, a conventional rolling bearing (conventional specification) in which a notch or a taper is not formed in the cage is different from a radial dimension at both axial ends of the cage as shown in Patent Document 1. A rolling test was performed using a rolled bearing (taper specification). FIG. 9 is a graph showing the results of this rotation test. From FIG. 9, according to the rolling bearing of this specification in which the notch 15 is formed on the inner peripheral surface of the cage 10 and the bearing internal dimension ratio α satisfies 1.4 ≦ α ≦ 2.1, It can be seen that the temperature reduction effect is clearly obtained as compared with the taper type rolling bearing.

Thus, according to the rolling bearing 100 of the present embodiment, the notch 15 is formed on the inner peripheral surface of the cage 10, and the bearing internal dimension ratio α satisfies 1.4 ≦ α ≦ 2.1. By satisfy | filling, since lubricating oil does not stay in the rolling bearing 100, an efficient cooling effect can be acquired, without raising manufacturing cost. As a result, even when oil lubrication, particularly oil bath lubrication is used, it has a cooling capacity comparable to jet lubrication, and a sufficient temperature reduction effect can be obtained. Furthermore, the rolling bearing 100 can obtain a sufficient temperature reduction effect even when used in oil-air lubrication or splash lubrication as well as jet lubrication.

(Modification)
10 and 11 show a rolling bearing 100 ′ and a cage 10 ′ used for the rolling bearing 100 ′ according to a modification of the first embodiment. Also in this cage 10 ′, a cutout portion 15 having a rectangular cross section is formed on the inner peripheral surface. Furthermore,

annular notches

16 and 17 that are notched corresponding to the collars 3 of the outer ring 1 are formed at both ends in the axial direction of the cage 10 ′, that is, the outer peripheral surfaces of the

annular portions

11 and 12. . Even if the outer peripheral surface of the cage 10 ′ has such a shape, a temperature reduction effect can be obtained as long as the bearing internal dimension ratio α satisfies the relationship (1.4 ≦ α ≦ 2.1) described above.

(Second Embodiment)
Next, a rolling bearing according to a second embodiment of the present invention will be described with reference to FIGS. The same or equivalent parts as those in the first embodiment are denoted by the same or corresponding reference numerals, and the description will be simplified or omitted.

As shown in FIGS. 12 and 13, in the rolling bearing 200 according to the second embodiment, a notch 215 is formed on the inner peripheral surface of the column part 213 of the cage 210. Unlike the notch 15 in the first embodiment, the notch 215 is formed to have an arc cross section.

Thus also in the cutout portion 215 formed to have a circular arc cross-section, the cross-sectional area S _in, if it is possible to replace the equivalent sectional area S _in the notches 15 in the first embodiment, the bearing As long as the dimensional ratio α satisfies the above relationship (1.4 ≦ α ≦ 2.1), it is considered that the temperature reduction effect can be obtained as in the first embodiment.

Here, assuming that the cross-sectional area of one notch corresponding to one pocket is S _in , the sum ΣS _in of the cross-sectional areas of the notch is the notch amount h of the notch 215 and the notch 215. Using the notch length (axial dimension) M (see FIG. 12) and the number of cylindrical rollers 9 (number of pockets) z, it is expressed as follows.

Therefore, in order to make the cross-sectional area of the notch formed on the inner peripheral surface of the cage equivalent, the notch amount h should satisfy the following formula.

Thus, even when the notch 215 is formed to have an arc cross section, the sum ΣS _in of the sectional area of the notch is equivalently replaced, and the bearing internal dimension ratio α is the relationship described above ( As long as 1.4 ≦ α ≦ 2.1) is satisfied, a sufficient temperature reduction effect can be obtained.

(Third embodiment)
Next, a rolling bearing according to a second embodiment of the present invention will be described with reference to FIGS. The same or equivalent parts as those in the first embodiment are denoted by the same or corresponding reference numerals, and the description will be simplified or omitted.

As shown in FIGS. 14 and 15, in the rolling bearing 300 according to the third embodiment, the outer circumferential surface of the

annular portions

311 and 312 of the cage 310 is formed in an arc shape at a location adjacent to the pocket 314 in the axial direction. A recess 316 is formed. Therefore, the outflow part from which the lubricating oil is discharged in the rolling bearing 300 has a non-uniform cross section on the circumference.

Here, in the case where the outflow portion has a circumferentially uniform cross-section, the cross-sectional area S _out of the outflow portion (inner diameter of the collar 3) having an inner diameter of the outer ring 1 D _1, and the outer diameter D ₂ of the retainer 310 Can be expressed as follows.

When the cross section of the outflow portion is not uniform on the circumference, the difference (D ₁ -D ₂ ) between the inner diameter D _{1 of the} outer ring 1 and the outer diameter D ₂ of the cage 310, which is a parameter of the cross section area S _out of the outflow portion, is Can be equivalently replaced as follows.

Thus, even if the outflow portion has a circumferentially non-uniform cross section, it is sufficient as long as the cross sectional area S _out of the outflow portion is equivalently replaced and the bearing internal dimension ratio α satisfies the above relationship. A temperature reduction effect can be obtained.

Note that the present invention is not limited to the above-described embodiments, and modifications, improvements, and the like can be made as appropriate. In the embodiment described above, the rolling bearing is a cylindrical roller bearing, but other rolling bearings may be used. The cross-sectional shape of the notch formed on the inner peripheral surface of the cage is not limited to the rectangular shape described in the first embodiment or the arc shape described in the second embodiment, and the cross-sectional area of the notch is Any shape is possible as long as it can be equivalently replaced.

Further, in each of the above-described embodiments, the notches are formed in the column portions corresponding to all the pockets, but the total sum ΣS _in of the cross-sectional areas of the notches may be replaced with the notch amount h. As long as possible, notches may be formed in the pillars corresponding to only some pockets. Moreover, about the recessed part which can be formed in the outer peripheral surface of a holder | retainer, a recessed part may be formed corresponding to only some pockets.

This application is based on Japanese Patent Application No. 2014-001139 filed on Jan. 7, 2014, the contents of which are incorporated herein by reference.

100, 100 ′, 200, 300 Rolling bearing 1 Outer ring 6 Inner ring 9 Cylindrical roller (rolling element)
10, 10 ', 210, 310

Cage

15, 215, 315 Notch z Number of cylindrical rollers L Length of cylindrical roller (axial dimension)
Da Outer diameter dimension of cylindrical roller dm Bearing pitch circle diameter D ₁ Inner diameter of outer ring D ₂ Outer diameter of cage h Notch amount (diameter dimension of notch)

Claims

Outer ring,
Inner ring,
A cage for holding a plurality of rolling elements incorporated between the outer ring and the inner ring in a plurality of pockets provided at equal intervals in the circumferential direction;
A rolling bearing comprising:
A notch is formed on the inner peripheral surface of the cage,
Radial dimension h of the notch, the inner diameter D 1 of the outer ring, the outer diameter D 2 of the retainer, the bearing pitch circle diameter dm, the number z of the rolling element, the outer diameter Da of the rolling element, A rolling bearing according to claim 1, wherein a bearing internal dimension ratio α represented by the formula (1) satisfies 1.4 ≦ α ≦ 2.1 by the axial dimension L of the rolling element.
The rolling bearing according to claim 1, wherein the rolling bearing is used in oil lubrication.
The rolling bearing according to claim 2, wherein the oil lubrication is selected from jet lubrication, oil-air lubrication, splash lubrication, and oil bath lubrication.