JPH0635656U - Rolling bearing - Google Patents

Abstract

(57) [Summary] (Modified) [Purpose] Encapsulated lubricant is continuously supplied in small amounts during operation.
In addition, an appropriate amount of lubricant is supplied even during high-speed rotation to obtain an excellent lubrication life. [Constitution] Inner ring spacer 4 having a lubricant reservoir space 7 provided therein
It is formed of the inner peripheral member 4a and the outer peripheral member 4b. Member 4
The mating surfaces 9 of a and 4b are formed from the lubricant reservoir space 7 to the rolling element 5
It becomes a part of the lubricant outflow passage 11 opened near the rolling passage 12 of the above. The outer peripheral member 4b is made of a material having a smaller linear expansion coefficient than the inner peripheral member 4a, or a material having a larger ratio E / γ between the specific gravity γ and the Young's modulus E of the material than the inner peripheral member 4a. The lubricant in the lubricant reservoir space 7 oozes out by a capillary phenomenon or centrifugal force and is supplied to the rolling elements 5. At the time of high speed rotation, the centrifugal force acting on the lubricant in the space 7 becomes strong and it tends to flow out, but the gap of the fitting surface 9 becomes small due to the difference in the coefficient of linear expansion and the difference in the ratio E / γ. , Keep proper outflow.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a grease-lubricated bearing, and more particularly to a rolling bearing suitable for a part that rotates at a low temperature and high speed, such as a bearing for a main shaft of a machine tool.

[0002]

[Prior art]

 For grease lubrication, grease is generally used by filling the interior of the bearing, that is, the gaps between the rolling elements, inner and outer rings, cages, etc.

In this case, if the amount of grease retained between the members is small, the lubricating life of the bearing may be shortened. It is possible to increase the amount of grease to be filled to some extent, but if a large amount of grease is filled between the above-mentioned components, the heat generated by the stirring resistance of the grease will increase at the beginning of operation, and excess grease will not be discharged or familiarized. There is a problem that the time required for running-in to improve the time becomes longer. In particular, when used in machine tools, heat generation in bearings affects machining accuracy, so it is necessary to reduce it as much as possible, and improved durability is also desired.

As a solution to such a problem, the applicant of the present invention has proposed a lubricant such as grease to be enclosed in a reservoir provided in the inner ring spacer to prolong the lubricating life of the bearing. (Practical application No. 3-49662, No. 3-77609). In these proposals, a minute gap created by unevenness of the surface roughness of the mating surface or a minute slit formed on the mating surface is used as the lubricant outflow path, and the lubricant from the pool to the rolling surface The flow of water is carried out by utilizing the capillary action due to the minute gaps or slits in the lubricant outflow channel and the centrifugal force due to rotation. Therefore, the effect of reducing the outflow amount is great, and the lubricant can be supplied in very small amounts.

[0005]

[Problems to be solved by the device]

 However, when the rotation speed becomes extremely high speed of dn = 500,000 or more, especially dn = 800,000 or more, the action of centrifugal force due to the rotation becomes large and flows out from the minute gap of the inner ring spacer. The flow rate of lubricant may be too high. In addition, the temperature rise due to high-speed rotation makes it easier for the lubricant to flow out due to a decrease in the viscosity of the lubricant, and may flow out in vain. The fact that the amount of lubricant outflow increases as the rotation speed increases may be advantageous depending on the material and structure of the bearing, but in hybrid bearings that use ceramic rolling elements, etc. Therefore, it is not necessary to increase the supply amount of the lubricant even at the high rotation speed as described above. Therefore, the lubricant is supplied more than necessary at the time of high speed rotation, and the effect of improving the lubricating life is reduced.

The object of the present invention is to supply a small amount of the lubricant enclosed in the reservoir portion during operation, and even if the rotation speed is high, there is no unnecessary increase in the supply amount, and a rolling bearing that can improve the lubrication life is achieved. Is to provide.

[0007]

[Means for Solving the Problems]

 In the rolling bearing according to the invention of claim 1, the inner ring spacer having the lubricant reservoir space provided inside is formed of an inner peripheral member and an outer peripheral member that are fitted into each other, and the outer peripheral member is compared with the inner peripheral member. The material has a small linear expansion coefficient. The fitting surface between the inner peripheral member and the outer peripheral member becomes a part of the lubricant outflow passage that opens from the lubricant reservoir space to the vicinity of the rolling passage of the rolling element.

In the rolling bearing of the second aspect of the present invention, the outer peripheral member of the inner ring spacer according to the first aspect is made of a material having a larger ratio E / γ between the specific gravity γ of the material and the Young's modulus E than that of the inner peripheral member. It is a thing. The linear expansion coefficient of the inner peripheral member and the outer peripheral member does not matter.

[0009]

[Action]

 According to this configuration, the lubricant or its components in the lubricant reservoir space passes through the fitting surface between the inner peripheral member and the outer peripheral member of the inner ring spacer and is subjected to the capillary force and centrifugal force caused by the rotation of the inner ring spacer. Supplied near rolling elements. Therefore, it is supplied in small amounts over a long period of time. When the rotation speed becomes higher than a certain level, the centrifugal force acting on the lubricant in the lubricant storage space becomes large, and the temperature rises, so that the viscosity of the lubricant or its components lowers, which facilitates the outflow. The increase in outflow rate is prevented as follows.

That is, in the case of the structure of claim 1, since the outer peripheral member of the inner ring spacer is made of a material having a smaller linear expansion coefficient than the inner peripheral member, the outer peripheral member of the inner peripheral member is not heated due to the temperature rise accompanying the high speed rotation. The radial surface thermally expands more than the inner diameter surface of the outer peripheral member. Therefore, the minute gap that forms the lubricant outflow path at the fitting surface between the outer peripheral member and the inner peripheral member becomes narrower, and the increase in the outflow rate is prevented regardless of the increase in centrifugal force acting on the lubricant and the decrease in viscosity. It

In the case of the structure of claim 2, at the time of high speed rotation, both the inner peripheral member and the outer peripheral member elastically expand slightly due to the centrifugal force, but the outer peripheral member is made of a material as compared with the inner peripheral member. Since the material E has a large ratio E / γ between the specific gravity γ and the Young's modulus E, the amount of expansion due to the centrifugal force is larger in the inner peripheral member than in the outer peripheral member. Therefore, the minute gap forming the lubricant outflow passage is narrowed at the fitting surface between the outer peripheral member and the inner peripheral member, and an increase in the outflow rate is prevented.

[0012]

【Example】

 An embodiment of this invention will be described with reference to FIGS. This embodiment is an example applied to an inner ring rotating type double-row angular contact ball bearing. In this double-row bearing, the inner ring 2 of each row of bearings 1 and 1 is individually provided and the outer ring 3 is shared, and an inner ring spacer 4 is provided between both inner rings 2 and 2. The rolling element 5 is spherical and is held in the pocket of the cage 6. The inner ring 2 is fixed to a rotating shaft (not shown), and the outer ring 3 is fixed to a housing which is a stationary member. The material of the rolling elements 5 is ceramics or bearing steel.

The inner ring spacer 4 is composed of two members, an inner peripheral member 4a and an outer peripheral member 4b that are fitted inside and outside, and a circumferential groove provided on the outer diameter surface of the inner peripheral member 4a and an outer peripheral member 4b. In between, a lubricant reservoir space 7 is formed. The inner peripheral surface of the inner peripheral member 4a is provided with a through hole 8 for venting air, which penetrates the lubricant reservoir space 7. This hole 8 does not necessarily have to be provided.

The inner peripheral member 4a and the outer peripheral member 4b are tightly fitted to each other, but a small gap is formed on the fitting surface 9 due to unevenness due to surface roughness (for example, 0.2 to 10 μm) of finish processing. To be done. The outer peripheral member 4b is made of a material having a smaller linear expansion coefficient than the inner peripheral member 4a. For example, the outer peripheral member 4b is made of steel and the inner peripheral member 4a is made of aluminum alloy.

Between the side end surface of the outer peripheral member 4b of the inner ring spacer 4 and the inner ring 2, a slit 10 having a slight width is provided all around or partially. The slit 10 and the fitting surface 9 constitute a lubricant outflow passage 11 which opens from the lubricant reservoir space 7 to the rolling passage 12 of the rolling element 5.

At the time of assembling the bearing, the rolling passage 12 is filled with a lubricant, but the lubricant is filled in the lubricant reservoir space 7 as much as possible by using a smaller amount than the usual filling. Lubricant In addition to general semi-solid or solid grease, liquid grease or plastic grease, oil-impregnated resin, woven cloth or felt containing lubricating oil, etc. is used as the lubricant to be filled in the reservoir space 7. be able to. Plastic grease is a composition in which a mixture of a resin such as ultra-high molecular weight polyethylene or ultra-high molecular weight polyolefin and grease is heated and melted and then solidified by cooling, and oil leaching has been developed.

According to this configuration, the lubricant or its components enclosed in the lubricant reservoir space 7 exudes from the fitting surfaces 9 of the inner and outer members 4a, 4b of the inner ring spacer 4 to both axial sides by a capillary phenomenon. . The lubricant or its components that have exuded to the side end surface of the inner ring spacer 4 flows in the outer radial direction by the centrifugal force associated with the rotation of the inner ring spacer 4, and is supplied to the raceway surface of the rolling path 12. When the lubricant is a semi-solid grease, the grease base oil mainly separates from the thickener and flows out.

In this bearing, since the lubricant or its components sealed in the lubricant reservoir space 7 is replenished little by little, the lubrication life is improved. Therefore, the amount of lubricant enclosed between the rolling path 12, the rolling elements 5, the cage 6 and other members can be reduced to allow a small amount of lubrication, which reduces heat generation due to stirring resistance and improves familiarity. The running-in required time is shortened.

When the rotation speed becomes a certain high speed or more, the centrifugal force acting on the lubricant in the lubricant reservoir space 7 becomes large, and the temperature rises, so that the lubricant or its components flow out due to a decrease in viscosity. However, the increase in outflow rate is prevented as follows. That is, since the outer peripheral member 4b of the inner ring spacer 4 is made of a material having a smaller linear expansion coefficient than that of the inner peripheral member 4a, the outer peripheral surface of the inner peripheral member 4a is changed to the inner diameter of the outer peripheral member 4b due to the temperature increase due to the high speed rotation. Thermal expansion is larger than the surface. Therefore, the small gap forming the lubricant outflow passage 11 is narrowed at the fitting surface 9 between the outer peripheral member 4b and the inner peripheral member 4a, and the outflow rate is reduced regardless of the increase in the centrifugal force acting on the lubricant and the decrease in viscosity. The increase is prevented. Therefore, the lubricant is not supplied more than necessary even during high-speed rotation, and the lubrication durability can be improved.

In the double-row bearing of FIG. 1, the outer peripheral member 4b of the inner ring spacer 4 may be made of a material having a larger ratio E / γ between the specific gravity γ of the material and the Young's modulus E than that of the inner peripheral member 4a. For example, the inner peripheral member 4a is made of steel and the outer peripheral member 4b is made of ceramics.

With this configuration, an increase in the amount of lubricant flowing out from the lubricant reservoir space 7 during high speed rotation is prevented as follows. That is, at the time of high-speed rotation, both the inner peripheral member 4a and the outer peripheral member 4b elastically expand slightly due to the centrifugal force, but the outer peripheral member 4b has a specific gravity γ and Young's material which are larger than those of the inner peripheral member 4a. Since the material has a large ratio E / γ with the ratio E, the amount of expansion due to centrifugal force is larger in the inner peripheral member 4a than in the outer peripheral member 4b. Therefore, the minute gap forming the lubricant outflow passage 11 is narrowed at the fitting surface 9 between the outer peripheral member 4b and the inner peripheral member 4a, and an increase in the outflow rate is prevented. Therefore, also in this case, excessive supply of lubricant during high speed rotation is prevented, and excellent lubrication durability is obtained.

FIG. 3 shows a modification of the inner ring spacer 4 used in the double row bearing of FIG. In this inner ring spacer 4 ', the outer peripheral member 4b is made of steel, the inner peripheral member 4a is made of resin, and the width dimension thereof is set so that the outer peripheral member 4b protrudes from the inner peripheral member 4a by a dimension δ on both sides. There is. Therefore, the axial load acting on the inner ring spacer 4'is received by the outer peripheral member 4b.

In this example, since the material is selected as described above, the outer peripheral member 4b has a smaller linear expansion coefficient than the inner peripheral member 4a, and the ratio E / γ between the specific gravity γ of the material and the Young's modulus E is It will be big. Therefore, at the time of high-speed rotation, the gap between the fitting surfaces 9 is narrowed due to both the difference in the linear expansion coefficient and the difference in the ratio E / γ, and the increase in the outflow rate from the lubricant reservoir space 7 is prevented. Further, when the inner peripheral member 4b is made of resin in this way, the inner ring spacer 4 can be made VA.

In each of the above embodiments, the lubricant reservoir space 7 is formed in an annular shape, but the lubricant reservoir space 7 may be divided into a plurality of portions in the circumferential direction. In addition, the fitting surface 9 between the inner peripheral member 4a and the outer peripheral member 4b forming the lubricant outflow passage 11 is provided with a fine axial groove or a group of intersecting grooves in a slanted lattice to increase the flow rate to some extent. It is good to try. Further, the present invention is not limited to the double row angular contact ball bearing, but can be applied to a single row angular contact ball bearing and other rolling bearings in general.

[0025]

[Effect of device]

 The rolling bearing according to the present invention is provided with an inner ring spacer having a lubricant reservoir space therein, and the inner ring spacer is composed of an inner peripheral member and an outer peripheral member that are fitted to each other, and the fitting surface thereof is filled with a lubricant outflow. Since it is a passage, the lubricant or its components enclosed in the lubricant reservoir space is supplied to the vicinity of the rolling elements by the centrifugal force caused by the capillary phenomenon and the rotation of the inner ring spacer. Therefore, the lubricant is supplied little by little over a long period of time, and excellent lubrication durability is obtained.

Further, in the case of the invention of claim 1, since the outer peripheral member is made of a material having a smaller linear expansion coefficient than the inner peripheral member, the thermal expansion difference between the inner and outer members when the temperature rises due to the high speed rotation. As a result, the gap between the fitting surfaces, which serves as a lubricant outflow path between the two members, becomes small. For this reason, even during high-speed rotation, the lubricant in the lubricant reservoir space is prevented from flowing out more than necessary, regardless of the increase in centrifugal force acting on the lubricant and the decrease in viscosity due to temperature rise. It is possible to improve the sex.

In the case of the invention of claim 2, since the outer peripheral member of the inner ring spacer is made of a material having a larger ratio E / γ of the material's specific gravity γ and Young's modulus E than the inner peripheral member, it is possible to rotate at a high speed. The difference in the amount of deformation in which these inner and outer members are elastically deformed by the centrifugal force reduces the gap between the fitting surfaces that serve as the lubricant outflow passage. Therefore, even in the case of this configuration, it is possible to prevent wasteful increase of the outflow rate at the time of high-speed rotation, and to improve lubrication durability.

[Brief description of drawings]

FIG. 1 is a partial sectional view of an embodiment of the present invention.

FIG. 2 is an enlarged view of the inner ring spacer.

FIG. 3 is a cross-sectional view of a modified example of the inner ring spacer.

[Explanation of symbols]

2 ... inner ring, 3 ... outer ring, 4, 4 '... inner ring spacer, 4a ... inner peripheral member, 4b ... outer peripheral member, 5 ... rolling element, 7 ... lubricant storage space, 9 ... fitting surface, 10 ... slit, 11 ... Lubricant outflow passage

Claims (2)

[Scope of utility model registration request] 1. An inner ring spacer, which is formed of an inner peripheral member and an outer peripheral member that are fitted into each other inside and outside and has a lubricant reservoir space between the two members, is provided, and a fitting surface between the inner peripheral member and the outer peripheral member is interposed. And a lubricant outflow passage that opens from the lubricant storage space to the vicinity of the rolling passage of the rolling element, and the outer peripheral member is made of a material having a smaller linear expansion coefficient than the inner peripheral member. 2. An inner ring spacer, which is formed by an inner peripheral member and an outer peripheral member that are fitted into each other inside and outside and has a lubricant storage space between the two members, is provided, and a fitting surface of the inner peripheral member and the outer peripheral member is interposed. A lubricant outflow passage that opens from the lubricant storage space to the vicinity of the rolling passage of the rolling element is provided, and the ratio E / γ between the specific gravity γ of the material and the Young's modulus E is larger than that of the inner peripheral member of the outer peripheral member. Rolling bearing made of material.