JP2008291970A - Rolling bearing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive bearing lubrication structure by adopting a structure which does not require a complicated form such as an oil supply hole at an inner ring in the case of adopting an under race lubrication method, in a main bearing rotating at high speed for a turbo refrigerator and the like wherein low friction loss is of great importance. <P>SOLUTION: In the rolling bearing device provided with the under race lubrication structure for supplying lubricating oil into the bearing via the oil supply hole 15 in a radial direction from a hollow part 13 provided for a rotation shaft 1, end surfaces 7a, 7b of an inner ring spacer 7 contacting with an end surface 3a of an inner ring 3 and an end surface 3b of another inner ring 3 in a plurality of rows of rolling bearings are provided with a slit 17 in a radial direction communicatable with the oil supply hole provided for the rotation shaft. An annular scoop groove 19 continuing in a circumferential direction and facing the slit 17 is provided for a retainer 6. At least part of the scoop groove is provided at an axial position same as a slit bottom part 17b in an outer diameter surface 17a of the slit. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a lubrication structure for a rolling bearing device used for a main shaft of a turbo compression machine or a machine tool, and in particular, reliably supplies a required amount of lubricating oil into a bearing at high speed rotation, reduces bearing loss, and The present invention relates to an improvement in a method for supplying lubricating oil that is inexpensive and enables good bearing lubrication.

As a main bearing that rotates at high speed, such as a conventional centrifugal chiller, generally, an outer ring 4 that is externally fitted to the rotary shaft 1 and rotates together with the rotary shaft 1 and an outer ring 4 that is fitted and fixed to the housing 2 are fixed. And a combination angular ball bearing comprising a combination of an angular ball bearing comprising a large number of rolling elements 5 incorporated between the inner ring 3 and the outer ring 4 and a retainer 6 that holds the rolling elements 5 at a predetermined interval. The inner ring spacer 7 and the outer ring spacer 8 are disposed between the bearings.
As a lubrication method in this type of bearing structure, for example, jet lubrication is employed.
FIG. 5 shows an example of this type of rolling bearing structure adopting a jet lubrication structure. A jet nozzle hole 9 for supplying lubricating oil to an outer ring spacer 8 disposed between the outer rings 4 and 4 is provided and lubricated. Oil is forcibly supplied into the bearing.

  However, according to the external jet lubrication, a large amount of lubricating oil is forcibly supplied from the jet nozzle hole 9 provided on the inner peripheral surface of the outer ring spacer 8, so that the cooling effect is large and a lubrication structure suitable for a high-speed bearing is provided. On the other hand, when a large amount of lubricating oil is not properly discharged, there is a problem that the lubricating oil is agitated by the rolling elements 5 to generate heat and increase the power loss of the bearing. It was.

As for the cage guide type, the lubricant supplied to the bearing is discharged while lubricating the guide surface by centrifugal force. Therefore, the outer ring guide method is usually adopted, but in this type the outer ring groove is used. The accumulated oil is difficult to be discharged and contributes to the increase in power loss.
Furthermore, the outer ring spacer 8 provided with the jet nozzle hole 9 has a disadvantage that it has a more complicated shape than the annular spacer and requires processing such as opening the jet nozzle hole 9, thereby increasing the cost.

As a lubrication structure suitable for a high-speed bearing rather than jet lubrication, for example, a so-called under-lace lubrication structure is known in which lubricating oil is supplied into the bearing from the rotating shaft 1 side through an oil supply hole 10 provided in the inner ring 3 as shown in FIG. It has been.
Compared to jet lubrication, by supplying only the required amount to the bearing, the resistance of the rolling element 5 to stir the lubricating oil decreases, the power loss of the bearing is kept low, and the inner ring guide type can be adopted. A large clearance can be secured between the inner diameter of 4 and the outer diameter surface of the cage 6, and as a result, the oil in the bearing can be easily discharged, so that the oil agitation loss can be kept low.

However, in the case of such a conventional under-lace lubrication structure, the oil supply hole 10 for supplying the lubricating oil into the bearing from the shaft 1 side is provided in the inner ring 3 and the oil scoop spacer 23 is attached, which increases the cost. There was a drawback.
As in FIG. 6, Patent Document 1 is known for a rolling bearing that employs an underlace lubrication structure in which an oil supply hole is provided in an inner ring.
JP 2000-192971 A

  The present invention has been made to solve such a problem, and the object of the present invention is to employ an under-lace lubrication method in a main bearing that rotates at a high speed such as a turbo refrigeration machine that places importance on low friction loss. In this case, an inexpensive bearing lubrication structure is provided by making the inner ring a structure that does not require a complicated shape such as an oil supply hole.

In order to achieve such an object, the first invention includes an inner ring externally fitted to the rotating shaft,
An outer ring disposed outside the inner ring;
A rolling element incorporated between the inner ring and the outer ring;
A cage for holding the rolling elements at a predetermined interval;
In a rolling bearing device having an under-lace lubrication structure for supplying lubricating oil into a bearing through a radial oil supply hole from a hollow portion provided in the rotating shaft,
A predetermined bearing component is in contact with the end surface of the inner ring, and a radial slit is provided on the end surface of the bearing component that is in contact with the end surface of the inner ring so as to communicate with an oil supply hole provided in the rotating shaft.
The cage has a region protruding in the axial direction from the inner ring end face with which the bearing component member is in contact, and an inner surface of the protruding region has an annular scoop groove facing the slit and continuing in the circumferential direction. Provided,
At least a part of the scoop groove is at the same axial position as the slit bottom portion on the outer diameter surface of the slit.

  According to a second invention, in the first invention, the retainer is an inner ring guide, and the scoop groove is formed in a concave shape having a larger diameter than the inner diameter surface of the retainer that faces the outer diameter surface of the inner ring and functions as a guide surface, The weir near the inner diameter surface of the cage in the axial direction of the scoop groove is the first weir, the weir near the protruding end is the second weir, the depth of the first weir is h1, and the depth of the second weir This is a rolling bearing device characterized by having a relationship of h1 <h2, where h2 is h2.

  A third invention is the rolling bearing device according to the first or second invention, wherein a part of the scoop groove is located in the bearing and faces the outer surface of the inner ring.

  A fourth invention is a rolling bearing device according to any one of the first to third inventions, wherein the bearing constituent member in contact with the inner ring end face is an inner ring spacer.

  According to a fifth invention, in the fourth invention, the rolling bearings are double-rowed, an inner ring spacer is provided between the bearings, and the oil supply holes provided in the rotating shaft are spaced apart in the axial direction of the rotating shaft. The rolling bearing device is characterized in that it is provided in parallel and the slits are provided on both end faces of the inner ring spacer facing the oil supply hole.

  According to the present invention, a main bearing that rotates at high speed, such as a turbo refrigerator that places importance on low friction loss, has a structure that does not require a complicated shape such as an oil supply hole in the inner ring when the under-lace lubrication method is adopted. Therefore, an inexpensive bearing lubrication structure can be provided.

Hereinafter, an embodiment of the present invention will be described.
In the present embodiment, a rolling bearing device having the form shown in the drawings will be described as an example of the present invention. However, the present embodiment is merely an example of the present invention and is not limited to the illustrated form. Alternatively, other rolling bearing devices employing a so-called under-lace lubrication structure may be used, and the design can be changed within the scope of the present invention.

  1 to 3 show a double-row rolling bearings J1 and J2 arranged between a rotating shaft (main shaft) 1 and a housing 2 that rotate at high speed, such as a centrifugal chiller, etc. It is a schematic sectional drawing of one Embodiment of this invention which employ | adopts an under race lubrication structure.

The rotating shaft 1 is formed in a hollow cylindrical shape, for example, and forms a bearing disposition region A1 formed in a small diameter via a stepped portion 11 continuous in the circumferential direction at a predetermined location on the outer peripheral surface 1a. The radial abutting surface 12 that is continuous in the circumferential direction functions as a surface portion that receives the end surface 3a of the inner ring 3 of one of the rolling bearings J1.
And in the predetermined area | region of the internal peripheral surface 13a of the hollow part (lubricant oil flow path) 13 of the axis | shaft 1, it is equipped with the lubricating oil reservoir part 14 of the concave groove shape continued in the circumferential direction, A predetermined position (a predetermined position in the deepest region) of the bottom surface 14a, for example, in this embodiment, four positions that are spaced apart by approximately 90 degrees in the circumferential direction from the inside of the lubricating oil reservoir 14 to the bearing arrangement region A1. A radial oil supply hole 15 is provided. In the present embodiment, the lubricating oil reservoir 14 is provided with oil supply holes 15 in parallel at the same axial position at a predetermined interval in the axial direction of the rotary shaft 1, and a total of eight locations within the lubricating oil reservoir 14. An oil supply hole 15 is provided.

In this embodiment, the lubricant reservoir 14 is recessed from a predetermined position 130a on the inner peripheral surface corresponding to an outer peripheral surface position (predetermined position A11 in the bearing disposition region A1) that is a predetermined distance away from the abutting surface 12 in the axial direction. The installation area has started. That is, the recessed region of the lubricating oil reservoir portion 14 in this embodiment starts from the inner peripheral surface position 130a corresponding to the position separated from the abutting surface 12 by approximately one rolling bearing in the axial direction, and the inner ring spacer 7 Is provided as an area up to an inner peripheral surface position 130b corresponding to a position where the inner ring end surface 3a of the other rolling bearing J2 contacts the end surface 7b of the inner ring spacer 7.
Therefore, according to this embodiment, by adopting such a configuration, an under-lace lubrication structure is provided in which lubricating oil is supplied from the hollow portion 13 of the rotating shaft 1 through the oil supply hole 15 into the bearing.

The rolling bearing includes an inner ring 3 that is externally fitted to the rotary shaft 1, an outer ring 4 that is disposed outside the inner ring 3 and is fitted inside the housing 2, and a rolling element that is incorporated between the inner ring 3 and the outer ring 4. (Balls) 5 and angular ball bearings J1 and J2 composed of a retainer 6 that holds the rolling elements 5 at a predetermined interval. The back surface is assembled by interposing a spacer between the angular ball bearings J1 and J2. A combined double-row configuration is adopted.
That is, in this embodiment, the spacers (the inner ring spacer 7 and the outer ring spacer 8) are in contact with the end faces 3a, 3b and 4a, 4b facing each other of the inner ring 3 and the outer ring 4, respectively. The inner ring end surface 3a of the one rolling bearing J1 is brought into contact with the abutting surface 12 of the rotary shaft 1, and a predetermined preload is applied by pressing the bearing nut 16 against the inner ring end surface 3b of the other rolling bearing J2. .
Further, in the rolling bearing used in the present embodiment, the angular ball bearings J1 and J2 having the form shown in the figure are adopted, but the rolling bearing used in the present invention is particularly limited to this. Instead, other known forms of rolling bearings can be used as appropriate within the scope of the present invention. Moreover, it is also within the scope of the present invention to use a roller instead of the rolling element 5 as a ball, and the design can be changed.

As shown in FIGS. 1 and 2, the inner ring spacer 7 has an inner diameter that allows the inner circumferential surface 70 to be fitted on the outer circumferential surface of the bearing arrangement area A 1 of the rotary shaft 1 and has a smaller diameter than the outer diameter of the inner ring 3. It is formed in the annular | circular shape which has the outer peripheral surface 71 formed in this.
In the present embodiment, the left and right end surfaces 7a and 7b in the axial direction of the inner ring spacer 7 form inclined peripheral surface portions 72 and 72 from the predetermined position of the end surface toward the inner peripheral surface 70, respectively. Therefore, the inner peripheral surface 70 is formed in a trapezoidal shape in a cross-sectional view narrower than the outer peripheral surface 71.

As shown in FIGS. 2A and 2B, the axially right and left end faces 7a and 7b of the inner ring spacer 7 contacting the end face 3a of one inner ring 3 and the end face 3b of the other inner ring 3 are A radial slit 17 that can communicate with an oil supply hole 15 provided in the rotary shaft 1 is provided.
In the present embodiment, the slits 17 are formed at four positions spaced approximately 90 degrees apart in the circumferential direction. That is, a total of eight slits 17 are provided on the left and right end faces 7a and 7b.
Accordingly, the slit 17 is provided on both end faces 7 a and 7 b of the inner ring spacer 7 so as to face the oil supply hole 15, and is formed in a rectangular shape in an end view, and the end face 3 a of one inner ring 3 and the other inner ring 3 When the left and right end surfaces 7a and 7b in the axial direction of the inner ring spacer 7 in contact with the end surface 3b are in contact with each other, the slits 17 function as flow paths for guiding the lubricating oil supplied from the oil supply holes 15 into the bearing.
Further, the inner rings 3, 3 of the present embodiment have circumferentially inclined surface portions 18, 18 by chamfering the inner diameters of the end surfaces 3 b, 3 a on the side in contact with the end surfaces 7 a, 7 b of the inner ring spacer 7, respectively. Therefore, it functions as a guide surface for guiding the lubricating oil in the radial direction of the slit 17 together with the inclined peripheral surface portions 72, 72 of the inner ring spacer 7.

As shown in FIGS. 1 and 3, the cage 6 is an inner ring guide type, and has an inner peripheral surface 6 a slightly larger in diameter than the outer peripheral surface 3 c of the inner ring 3, and the outer peripheral surface 6 b is an inner peripheral surface of the outer ring 4. It has a smaller diameter than 4c, and is formed in an overall annular shape having a plurality of substantially cylindrical rolling element holding portions (pockets) 6c in the circumferential direction. The cage 6 has a region protruding in the axial direction from the inner ring end face 3a (or 3b) with which the inner ring spacer 7 contacts.
The protruding region is continuous in the circumferential direction, and an annular scoop groove 19 that is continuous in the circumferential direction is provided on the inner peripheral surface of the protruding region.

The scoop groove 19 is formed in a concave shape having a larger diameter than the inner peripheral surface 6a of the cage that functions as a guide surface facing the outer peripheral surface 3c of the inner ring.
The depth of the scoop groove 19 is not particularly limited and can be changed within the scope of the present invention. However, in this embodiment, a weir near the inner peripheral surface 6a of the cage in the axial direction of the scoop groove 19 is provided. When the first weir 19a, the weir near the protruding end is the second weir 19b, the depth of the first weir 19a is h1, and the depth of the second weir 19b is h2, h1 <h2. A configuration having a relationship is adopted. That is, by having such a relationship, the lubricating oil pressed against the scoop groove 19 by centrifugal force is effective in the clearance between the guide surface (inner peripheral surface) 6a of the cage 6 and the outer peripheral surface 3c of the inner ring. Will flow in.
In the present embodiment, a part of the scoop groove 19 is located in the bearing and faces the outer peripheral surface 3c of the inner ring. At least a part of the scoop groove 19 is at the same axial position as the slit bottom portion 17 b on the outer diameter surface 17 a of the slit 17 of the inner ring spacer 7.

Therefore, according to the present embodiment, the lubricating oil pressed by the centrifugal force against the bottom portion 14a of the groove-shaped lubricating oil reservoir 14 provided in the hollow portion (lubricating oil flow path) 13 of the rotating shaft 1 is lubricated. It is formed between each oil supply hole 15 provided in the radial direction from the oil reservoir portion 14 toward the shaft outer peripheral surface (bearing arrangement region A1), and between each slit 17 of the inner ring spacer 7 and the inner ring end faces 3a and 3b. And then ejected toward the scoop groove 19.
The lubricating oil thus ejected is received by the scoop groove 19 located immediately above in the radial direction of the slit 17. Since the cage 6 also rotates together with the inner ring 3, the lubricating oil accumulated in the scoop groove 19 increases in pressure by the action of centrifugal force and is pressed against the scoop groove 19. (Circumferential surface) 6a and the inner ring outer peripheral surface 3c flow into a gap between the inner ring and the inside of the bearing is lubricated.

According to this embodiment, it can be said that the rolling bearing device of the present invention has the following effects.
(1) It is not necessary to form an oil supply hole in the inner ring 3.
(2) It is only necessary to provide a slit 17 on the end face of a bearing constituent member such as the inner ring spacer 7 in contact with the end face of the inner ring 3.
(3) The cage 6 only needs to be provided with a circumferential scoop groove 19.
Therefore, it is possible to suppress an increase in cost as compared with a rolling bearing device that employs this type of underlace lubrication structure.
Further, since the inner ring guide type having a lower friction loss than the outer ring guide type can be adopted as the guide type of the cage 6, it is effective in reducing the bearing power loss.
Further, the inner ring guide type may be worn by the guide surface 6a of the cage 6, but according to the present invention, it is possible to supply lubricating oil directly to the guide surface (inner circumferential surface) 6a of the cage 6. There is also a deterrent effect on the guide surface wear of the cage 6.
"Modification"

The shape and the number of the slits 17 are not particularly limited to those of the present embodiment. The slit 17 has a shape communicating with the oil supply hole 15 and capable of supplying the lubricating oil from the oil supply hole 15 toward the scoop groove 19 of the cage 6. It is sufficient that at least one slit 17 is provided, and the design can be changed within the scope of the present invention.
The scoop groove 19 can be configured such that the first weir 19a is inclined toward the inside of the bearing and is within the scope of the present invention. With this configuration, the lubricating oil supplied into the scoop groove 19 is more strongly supplied into the bearing by centrifugal force as the rotation speed becomes higher.
In the present embodiment, the lubricating oil reservoir portion 14 is described with reference to an embodiment in which the lubricating oil reservoir portion 14 is continuous in a concave groove shape in the circumferential direction. However, the lubricating oil reservoir portion 14 is provided with an oil supply hole 15. It may be provided by being intermittently recessed only in the peripheral region.

4A and 4B show a second embodiment of the present invention, in which FIG. 4A is a schematic sectional view with a part omitted, and FIG. 4B is a schematic sectional view of a spacer.
In the present embodiment, a single row rolling bearing J3 is arranged between the rotary shaft 1 and the housing 2, and an under-lace lubrication structure is adopted as a method for supplying lubricating oil into the bearing. It is a schematic sectional drawing of a form.

  In the present embodiment, a concave groove-shaped lubricating oil reservoir 14 continuous in the circumferential direction is provided in a predetermined region on the inner peripheral surface of the hollow portion (lubricating oil flow path) 13 of the rotating shaft 1 in the same manner as in the first embodiment. However, the position and area size are different. That is, the concave portion of the lubricating oil reservoir portion 14 is recessed from the predetermined position 130c on the inner peripheral surface corresponding to the position near the center of the inner ring 3 of the rolling bearing J3 that is fitted on the bearing arrangement region A1 formed on the outer periphery of the rotating shaft 1. An installation area is started, and a recessed area having a size ending at a predetermined position 130d on the inner peripheral surface corresponding to the position of the end face 7b of the inner ring spacer 7 in contact with the end face 3b of the inner ring 3 is used.

  An oil supply hole 15 penetrating in the radial direction from the lubricating oil reservoir 14 to the outer peripheral surface of the rotating shaft (bearing arrangement region A1) is provided at a substantially central position in the axial direction of the lubricating oil reservoir 14. The oil supply holes 15 are respectively formed at four positions spaced approximately 90 degrees apart in the circumferential direction.

The inner ring spacer 7 has a radius that can communicate with each oil supply hole 15 provided in the rotary shaft 1 on an end surface 7a on the side in contact with the inner ring end surface 3b (the end surface on the left side when viewed from the front in FIG. 4), as shown in FIG. Directional slits 17 are provided.
Even in the present embodiment, similarly to the first embodiment, slits 17 are formed at four positions spaced apart by approximately 90 degrees in the circumferential direction, and each slit 17 is connected to each oil supply hole 15. Communicate.
Also in this embodiment, as in the first embodiment, the inner ring 3 is provided with a chamfered portion 18 on the inner diameter side of the end surface 3b in contact with the end surface 7a of the inner ring spacer 7.
Since the structure of the cage 6 is the same as that of the cage 6 described in the first embodiment, the description thereof is cited and the description thereof is omitted here.
In the figure, reference numeral 20 denotes an outer ring restraining lid which is fixedly attached to the end face of the housing 2 with bolts 21 and the like, and which restrains the end face 4b of the outer ring 4, and 22 is a bearing nut in contact with one end face 7b side of the inner ring spacer 7. A predetermined preload is applied by the tightening force of the nut 22.
Since the other configurations and the operational effects of the present embodiment are the same as those of the first embodiment, the same reference numerals are given to the same portions, the description thereof is used, and the description here is omitted.

It is a schematic sectional drawing which abbreviate | omits and shows one Embodiment of this invention rolling bearing apparatus. (A) is a schematic sectional drawing which shows one Embodiment of the spacer used for this embodiment, (b) is a schematic side view. It is an expansion schematic sectional drawing which shows the depth of the scoop groove | channel provided in the holder | retainer of this embodiment. (A) is schematic sectional drawing which abbreviate | omits some other embodiment of this invention rolling bearing apparatus, and (b) is a schematic sectional drawing which shows one Embodiment of the spacer used for this embodiment. It is a schematic sectional drawing which abbreviate | omits and shows an example of a prior art. It is a schematic sectional drawing which omits some other prior art examples.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rotating shaft 13 Hollow part 15 Oil supply hole 3 Inner ring 3a, 3b End surface 4 Outer ring 5 Rolling body 6 Cage 19 Scoop groove 7 Inner ring spacer 7a, 7b End surface 17 Slit 17a Outer diameter surface 17b Slit bottom

Claims (5)

An inner ring fitted on the rotation shaft;
An outer ring disposed outside the inner ring;
A rolling element incorporated between the inner ring and the outer ring;
A cage for holding the rolling elements at a predetermined interval;
In a rolling bearing device having an under-lace lubrication structure for supplying lubricating oil into a bearing through a radial oil supply hole from a hollow portion provided in the rotating shaft,
A predetermined bearing component is in contact with the end surface of the inner ring, and a radial slit is provided on the end surface of the bearing component that is in contact with the end surface of the inner ring so as to communicate with an oil supply hole provided in the rotating shaft.
The cage has a region protruding in the axial direction from the inner ring end face with which the bearing component member is in contact, and an inner surface of the protruding region has an annular scoop groove facing the slit and continuing in the circumferential direction. Provided,
At least a part of the scoop groove is at the same axial position as the slit bottom on the outer diameter surface of the slit. The cage is an inner ring guide,
The scoop groove is opposed to the inner ring outer diameter surface, and is formed in a concave shape having a larger diameter than the inner diameter surface of the cage that functions as a guide surface.
The weir near the inner surface of the cage in the axial direction of the scoop groove is the first weir, the weir near the protruding end is the second weir,
2. The rolling bearing device according to claim 1, wherein a relationship of h1 <h2 is established, where h1 is a depth of the first weir and h2 is a depth of the second weir.   3. The rolling bearing device according to claim 1, wherein a part of the scoop groove is located in the bearing and faces the outer surface of the inner ring.   The rolling bearing device according to any one of claims 1 to 3, wherein the bearing constituent member in contact with the end face of the inner ring is an inner ring spacer. Rolling bearings are double-row, with inner ring spacers between the bearings,
The oiling holes provided in the rotating shaft are arranged in parallel at a predetermined interval in the axial direction of the rotating shaft,
The rolling bearing device according to claim 4, wherein the slits are provided on both end faces of the inner ring spacer so as to face the oil supply hole.

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