JP2007211802A - Cage for rolling bearing, and submersible pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cage for a rolling bearing capable of constantly maintaining lubrication performance and rotation performance of the bearing for a long time and to provide a submersible pump maintaining constant operation accuracy for a long time and excellent in durability. <P>SOLUTION: The cage 20 for the rolling bearing is provided along a circumferential direction with a plurality of pockets 20p for holding a plurality of rolling elements 6c one by one and a plurality of pillar portions 20h for interconnecting adjacent pockets, has openings 20k on one side for inserting the rolling elements in the pockets and is closed at the other end. The pillar portion is provided with at least one through hole 20a for letting lubricant flow for lubricating the rolling bearing and the through hole is formed to penetrate from the one side of the pillar portion to the other side. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a rolling bearing cage improved in terms of lubrication performance, and further relates to a submersible pump using a bearing in which the cage is incorporated.

Conventionally, for example, a submersible pump, a power tool, a machine tool, and an induction motor are known as various devices having a vertical shaft structure in which a main shaft extends in a vertical direction.
Among these, for example, as a configuration of the submersible pump, a configuration as shown in FIG. 4 can be cited as an example, and the submersible pump has an oil chamber S and a motor unit M standing upright above the pump unit P. A single main shaft 2 penetrating from the motor part M through the oil chamber S to the pump part P is extended in the vertical direction so as to be rotatable. In this case, the motor unit M includes an electric motor (motor) 4 for rotating the main shaft 2 and two rolling bearings 6 and 8 that rotatably support the main shaft 2 (lower bearings (lower bearings in FIG. 4). 6) and the upper bearing (upper bearing 8)) in the figure are accommodated. In addition, the pump unit P accommodates an impeller 10 having a plurality of blades 12 for pumping and circulating the liquid (for example, various kinds of drainage) in the pump unit P.

  By the way, since such a submersible pump is used in water, liquid (for example, various drainage etc.) may enter the inside of the pump from the outside and may deteriorate the performance of the pump. Therefore, as described above, the oil chamber S is provided between the pump portion P and the motor portion M, and the mechanical seal 18 for keeping the motor portion M in an airtight state is disposed inside the oil chamber S. Yes. Also, in the oil chamber S, a lubricating liquid (for example, lubrication) is used to lubricate and cool the sliding portion of the mechanical seal 18 (the sliding portion on the pump portion P side and the sliding portion on the motor portion M side). Oil). This prevents wear and temperature rise due to friction of the sliding portion of the mechanical seal 18.

However, the life of the mechanical seal 18 is generally shorter than that of the bearings 6 and 8 that support the main shaft 2. For this reason, for example, when the wear of the mechanical seal 18 progresses, the sealing performance may be reduced and a gap may be generated in the sliding portion.
For example, if a gap occurs in the sliding part on the pump part P side, foreign substances (metal powder, sludge, etc.) contained in various wastewaters enter the oil chamber S, and the foreign substances are enclosed in the oil chamber S. In some cases, it may be mixed in the lubricating fluid (for example, lubricating oil). Further, when a gap is generated in the sliding part on the motor part M side, for example, lubricating oil mixed with foreign matter may enter the bearings 6 and 8.

  In this case, for example, the foreign matter is caught between the raceway surface of the raceway and the rolling surface of the rolling element, and the raceway surface and the rolling surface are scratched. May occur. As a result, the bearings 6 and 8 cannot be used with a constant rotational accuracy over a long period of time. Further, for example, the lubricant (for example, grease) enclosed in the bearings 6 and 8 may be softened and the grease may leak (outflow) from the inside of the bearing to the outside of the bearing. In this case, the amount of grease in the bearing decreases, and the bearings 6 and 8 become insufficiently lubricated.For example, the raceway surface of the bearing ring and the rolling surface of the rolling element are damaged (worn or seized) by friction. There is. As a result, the bearings 6 and 8 cannot be used with a constant rotational accuracy over a long period of time.

  Therefore, as one of the measures for solving the above-mentioned problems, conventionally, a measure for interposing a sealing plate (not shown) for sealing the inside of the bearings 6 and 8 between the bearing rings of the bearings 6 and 8 is used. There is. According to such a measure, the lubricant (e.g., grease) sealed inside the bearings 6 and 8 is prevented from leaking to the outside of the bearings 6 and 8, and foreign substances (e.g., , Metal powder, sludge, etc.) can be prevented from entering the bearings 6 and 8. Furthermore, as a measure for solving the above-described problem, for example, in Patent Document 1, a slope is provided on the outer diameter surface of a cage (not shown) incorporated between the races, and lubrication is performed by rotating the cage. Means for supplying an agent (for example, grease or lubricating oil) to the opening of the cage is disclosed as an example. Further, for example, Patent Document 2 includes an example in which a notch that is inclined is provided in an inner diameter portion of a cage (not shown) and a lubricant (for example, grease or lubricating oil) is stored in the notch. It is disclosed as. Thereby, the lubrication performance of the bearing can be maintained constant, and the bearing can be used with a constant rotational accuracy over a long period of time.

Incidentally, as described above, the submersible pump is provided with the oil chamber S between the pump portion P and the motor portion M, and the mechanical seal 18 is disposed inside the oil chamber S, so that the motor portion M It is kept airtight. In the submersible pump having such a configuration, the temperature of the bearings 6 and 8 rises when the electric motor (motor) 4 disposed in the motor unit M rotates and generates heat. For this reason, for example, the lubricant (grease) enclosed in the bearings 6 and 8 may be softened or the base oil constituting the grease may evaporate. If the bearings 6 and 8 are poorly lubricated, the temperature of the bearings 6 and 8 is likely to rise further, so that the softening of the grease and the evaporation of the base oil easily occur. Further, since the submersible pump has a vertical shaft structure, when the grease sealed in the bearings 6 and 8 is softened, the grease is subjected to the action of gravity in a predetermined direction (the direction of the oil chamber (FIG. 4 Move down))). For this reason, even when a sealing plate as described above is interposed between the races, or when a slope (see Patent Document 1) or a notch (see Patent Document 2) is provided in the cage, The leakage prevention effect and the storage effect are not sufficiently exhibited, and the grease sealed inside the bearings 6 and 8 may leak to the outside of the bearings 6 and 8.
As a result, the amount of grease in the bearing decreases, and the bearings 6 and 8 become insufficiently lubricated.For example, the raceway surface of the bearing ring and the rolling surface of the rolling element are damaged by friction (wearing or seizing), and the bearing 6 and 8 may not be able to be used with a certain rotational accuracy over a long period of time.
JP 2003-314558 A JP 2005-214259 A

  The present invention has been made in order to solve such a problem, and an object of the present invention is to provide a rolling bearing cage capable of maintaining the lubrication performance of a rolling bearing constant over a long period of time. Another object of the present invention is to provide a submersible pump excellent in durability that maintains a constant operation accuracy.

  In order to achieve such an object, a rolling bearing retainer according to the present invention includes a plurality of pockets for holding a plurality of rolling elements one by one and a plurality of column portions for connecting adjacent pockets to each other. It is provided along the direction, has an opening for inserting the rolling element into the pocket on one side, and is closed on the other side. In such a configuration, the column portion is provided with at least one through hole for flowing a lubricant for lubricating the rolling bearing, and the through hole extends from one side of the column portion to the other side. Is formed. In this case, at least one lubricant reservoir for storing the lubricant is provided on the other side of the rolling bearing cage, and the lubricant reservoir is formed in communication with the through hole. ing.

  In order to achieve such an object, the submersible pump according to the present invention includes an electric motor that rotates a main shaft extending in the vertical direction, and a motor that houses a plurality of rolling bearings that rotatably support the main shaft. And a pump part in which an impeller attached to the lower end side of the main shaft is housed, and an oil having a mechanical seal disposed between the motor part and the pump part for keeping the motor part airtight The room is erected vertically. In such a configuration, the rolling bearing disposed at least near the oil chamber uses any of the above-described rolling bearing retainers, and can freely roll between the pair of race rings and the race rings. The rolling bearing retainer is assembled between the bearing rings with the opening facing upward in the vertical direction when the rolling bearing supports the main shaft. ing.

  ADVANTAGE OF THE INVENTION According to this invention, while providing the rolling bearing retainer which can maintain the lubrication performance of a rolling bearing constant over a long period of time, it is the water which was excellent in durability which maintains a constant driving | operation precision over a long period of time. A pump can be provided.

  Hereinafter, a rolling bearing cage and a submersible pump according to an embodiment of the present invention will be described with reference to the accompanying drawings. The rolling bearing cage according to the present invention can be used for various types of rolling bearings that rotatably support a main shaft (vertical shaft) extending in the vertical direction. Examples of such a vertical shaft structure include a submersible pump, an electric tool, a machine tool, and an induction motor. In the following description, a case where a submersible pump is applied is assumed as an example.

FIG. 2A shows a submersible pump according to the present embodiment, and the submersible pump is configured by an oil chamber S and a motor unit M standing upright in the vertical upper direction of the pump unit P. At the same time, one main shaft 2 penetrating from the motor part M to the pump part P through the oil chamber S is extended in the vertical direction so as to be freely rotatable.
In the configuration shown in FIG. 2A, the motor unit M includes an electric motor (motor) 4 that rotates the main shaft 2 extending in the vertical direction, and a plurality (two) of rollers that rotatably support the main shaft 2. Bearings 6 and 8 are accommodated. In this case, the two rolling bearings 6 and 8 are arranged so as to sandwich the motor 4 from both sides in the extending direction of the main shaft 2 (vertical direction in FIG. 2A), and the rolling bearing (lower bearing). 6 is positioned on the lower side of FIG. 2 (a), and the rolling bearing (upper bearing) 8 is positioned on the upper side of FIG. 2 (a). The pump part P is attached to the lower end side of the main shaft 2 (the lower side of FIG. 2A), and a plurality of liquids for pumping and circulating the liquid (for example, various kinds of drainage) in the pump part P. An impeller 10 having a plurality of blades 12 is accommodated.

  The motor 4 is provided with a rotor 4a fixed to the main shaft 2 and a stator 4b fixed to the frame 14. For example, when the current is supplied to the stator 4b, the stator 4b and the rotor 4a Due to the magnetic interaction between them, the motor 4 can rotate the main shaft 2. Thereby, the submersible pump can circulate while circulating the liquid (for example, various waste water etc.) in the pump part P, when the several blade | wing 12 of the impeller 10 attached to the main shaft 2 rotates. .

  The oil chamber S is located between the motor part M and the pump part P, and a mechanical seal 18 for keeping the motor part M airtight is disposed therein. In this case, the mechanical seal 18 is fitted on the main shaft 2. Thereby, for example, it is possible to prevent liquid (for example, various kinds of drainage) pumped from the pump unit P from entering the motor unit M, and as a result, the motor unit M can be kept airtight. In addition, since the seal | sticker of arbitrary formats can be applied as the mechanical seal 18, the format is not specifically limited here. For example, the mechanical seal 18 has sliding portions (sliding surfaces) (two in total) at both ends thereof (the end portion on the pump portion P side and the end portion on the motor portion M side (upper and lower ends in FIG. 2A)). And a so-called monocoil double seal type seal that applies surface pressure to each sliding surface by one coil spring (not shown). In addition, inside the mechanical seal chamber S, a lubricating liquid (for example, lubricating oil) for sealing and cooling the sliding surface of the mechanical seal 18 is enclosed.

  The two rolling bearings (the lower bearing 6 and the upper bearing 8) that rotatably support the main shaft 2 are paired with bearing rings (inner rings 6a, 8a and outer rings 6b, 8b) and a plurality of rolling elements (balls) 6c, 8c that are rotatably incorporated between raceways formed on the opposing surfaces of the inner rings 6a, 8a and the outer rings 6b, 8b. In this case, the two rolling bearings 6 and 8 are provided with a lubricant (for example, a lubricant for lubricating the raceway surfaces of the bearing rings (inner rings 6a and 8a and outer rings 6b and 8b) and the rolling surfaces of the rolling elements 6c and 8c). , Grease and lubricating oil) are enclosed in the inside.

  FIG. 2 (b) shows an example of the configuration of the lower bearing 6, and the lower bearing 6 holds a plurality of rolling elements (balls) 6c that are rotatably held one by one. A vessel 20 is incorporated between the inner and outer rings 6a, 6b. In the configuration shown in FIG. 2B, the lower bearing 6 is provided with a sealing plate 22 between the inner and outer rings 6a and 6b for sealing the inside of the bearing. In this case, the sealing plate 22 is a contact type seal in which an annular steel plate (for example, a flat core made of various metals) is coated with an elastic material (for example, a sealing material such as rubber or synthetic resin). The seal 22 is applied as an example, and the seal 22 is interposed on each of both sides (the upper side and the lower side of FIG. 2B) sandwiching the rolling elements (balls) 6c (two in total). Further, the seal 22 is fixed to a mounting groove 6m whose outer diameter portion is continuously formed in the circumferential direction along the inner diameter surface of the outer ring 6b, while the tip (lip 22p) of the inner diameter portion is the inner ring 6a. It is positioned so as to come into contact with the seal groove 6s formed continuously in the circumferential direction along the outer diameter surface. In addition, since the magnitude | size, the shape, and the number of the seal | sticker 22 are arbitrarily set by the magnitude | size of the lower side bearing 6, etc., for example, it does not specifically limit here.

  As a result, the inside of the lower bearing 6 is maintained in a sealed state. For example, a lubricant (eg, grease) sealed inside the bearing leaks to the outside of the bearing, or foreign matter (eg, water or dust) outside the bearing. ) Can be prevented from entering the bearing. Note that, for example, even when the lubricating liquid (for example, lubricating oil) R sealed in the oil chamber S leaks from the oil chamber S and enters the motor unit M, the outside of the lower bearing 6 ( For example, the lubricating oil R pushed up from the lower part of FIG. 2 (b) and pressed against the lip 22p of the seal 20 has a large diameter of the seal 22 due to the centrifugal force generated by the rotation of the inner ring 6a. A force (loop force) Fp moving in the direction (the outer diameter direction of the seal 22 (the left direction in FIG. 2B)) is received. For this reason, the force Ff of the lubricating oil R moving in the inner direction of the lower bearing 6 (upward in FIG. 2B) is suppressed, and as a result, the lubricating oil R enters the lower bearing 6. This can be effectively prevented.

  1A to 1D show an example of the configuration of the cage 20. The cage 20 is formed in a cylindrical shape, and surrounds a plurality of pockets 20p for holding a plurality of rolling elements (balls) 6c one by one and a plurality of column portions 20h for connecting adjacent pockets 20p. It is arranged along the direction. The cage 20 has an opening 20k for inserting the rolling element (ball) 6c into the pocket 20p on one side (the upper side in FIG. 1B) and the other side (the lower side in FIG. 1B). Assume a coronal shape with a closed side. In this case, in the state where the lower bearing 6 supports the main shaft 2 (see FIG. 2 (a)), the cage 20 has its opening 20k directed upward in the vertical direction (upper side in FIG. 1 (d)). It is incorporated between the inner and outer rings 6a, 6b of the lower bearing 6. The column 20h of the cage 20 is provided with a pair of claws 20t protruding so as to partially cover the opening 20k, and the rolling elements (balls) 6c inserted into the pockets 20p are provided with these claws. It is held in the pocket 20p in a state of being sandwiched by the portion 20t. The material of the cage 20 is not particularly limited. For example, a resin such as PTFE (tetrafluoroethylene), PPE (polyphenylene ether), and PA (polyamide) can be arbitrarily applied. As an example, a case where a PA (polyamide) cage 20 is applied is assumed.

  In the present embodiment, the pillar portion 20h of the cage 20 is provided with at least one through hole 20a for allowing a lubricant (for example, grease or lubricating oil) G to lubricate the lower bearing 6 to flow. The through-hole 20a is formed so as to penetrate from one side (upper side of FIG. 1B) to the other side (lower side of FIG. 1B) of the column portion 20h. As an example, in the configuration shown in FIGS. 1A to 1D, the through hole 20a extends from one side (upper side in FIG. 1B) to the other side (lower side in FIG. 1B) of the column 20h. It is configured as a cylindrical hole penetrating up to 1 mm in diameter, one for each column 20h (total of seven (partially omitted in FIG. 1 (c))), equally spaced in the circumferential direction Is provided. Note that the size, shape, and number of the through holes 20a are not particularly limited because they are arbitrarily set depending on the size of the cage 20, the number of pockets 20p (rolling elements (balls) 6c), and the like. For example, the through hole 20a may be configured as a conical hole or a rectangular hole. Further, for example, a plurality of through holes 20a may be provided in all the column parts 20h, or one or a plurality of through holes 20a may be provided in some of the column parts 20h. Furthermore, the method for forming the through hole 20a is not particularly limited, and for example, the through hole 20a may be integrally formed with the cage 20 or may be perforated with respect to the column portion 20h after the cage is molded.

  Further, the retainer 20 has a lubricant reservoir 20c for storing a lubricant (for example, grease or lubricating oil) G on the closed side (the other side described above (the lower side in FIG. 1B)). Is provided, and the lubricant reservoir 20c is formed in communication with the through hole 20a. As an example, in the configuration shown in FIGS. 1A to 1D, the lubricant reservoir 20c is a concave portion formed on the column 20h from the closed side of the cage 20 (the lower side in FIG. 1B). It is configured. In this case, the lubricant reservoir 20c is provided between the inner diameter surface and the outer diameter surface of the cage 20 and between the adjacent pockets 20p. Further, a total of seven lubricant reservoirs 20c are formed in a rectangular shape communicating with each through-hole 20a one by one (partially omitted in FIG. 1C), and the seven lubricant reservoirs 20c are circumferential. Are provided at equal intervals. In addition, since the magnitude | size, the shape, and the number of the lubricant storage part 20c are arbitrarily set by the magnitude | size of the holder | retainer 20, the number of through-holes 20a, etc., for example, it does not specifically limit here. For example, the lubricant reservoir 20c may be formed in a cylindrical shape or a conical shape. Further, for example, a plurality of lubricant reservoirs 20c may be provided in all the column parts 20h, or one or a plurality of lubricant reservoirs 20c may be provided in some of the column parts 20h. Furthermore, the formation method of the lubricant reservoir 20c is not particularly limited. For example, the lubricant reservoir 20c may be formed integrally with the cage 20, or after the cage is molded, the closed side of the cage 20 (the lower side in FIG. 1B). You may make it perform cutting.

Here, the lubrication performance of the cage 20 according to the present embodiment shown in FIGS. 1A to 1D will be described in comparison with the conventional cage 50 as shown in FIGS. 5A and 5B. To do.
As shown in FIGS. 5 (a) and 5 (b), the conventional retainer 50 is not provided with a through hole 20a (see FIGS. 1 (a) to 1 (d)), and the inside of the lubricant reservoir 20c. Therefore, the air layer L is likely to be generated in the lubricant reservoir 20c. As a result, the fluidity of the lubricant (for example, grease) G is poor, and the grease G stagnates near the entrance of the lubricant reservoir 20c (the closed side of the cage 50 (the lower side of FIG. 5B)). (See FIG. 5B). For this reason, it takes time until the grease G adheres and is stored in the lubricant reservoir 20c, and the amount of adhesion and the amount of storage are also reduced. In the configuration shown in FIGS. 5A and 5B, the cage 50 has a crown shape, and the pocket 20p, the column portion 20h, and the claw portion 20t are the same as those shown in FIGS. 1A to 1D. Each is configured similarly to the cage 20 according to the embodiment.

  On the other hand, in the cage 20 according to the present embodiment shown in FIGS. 1A to 1D, as described above, in addition to the lubricant reservoir 20c, the through-hole communicating with the lubricant reservoir 20c. By providing 20a, an air passage (through hole 20a) in the lubricant reservoir 20c is secured, so that no air layer L (see FIG. 5B) is generated in the lubricant reservoir 20c. As a result, the fluidity of the lubricant (for example, grease) G is good, the grease G can be stirred by the rotation of the lower bearing 6 (the retainer 20), and can be easily attached to the lubricant reservoir 20c. The lubricant can be easily stored in the lubricant storage unit 20c (see FIG. 1D). For this reason, the grease G can be immediately distributed to the inside of the lower bearing 6 (for example, the raceway surfaces of the inner and outer rings 6a and 6b and the rolling surfaces of the rolling elements (balls) 6c), and the lower side. The bearing 6 can be immediately brought into a stable and good lubricating state.

  Further, by providing the retainer 20 with the through hole 20a and the lubricant reservoir 20c, the amount of grease G attached to the inside of the lower bearing 6 (the lubricant reservoir 20c of the cage 20) and the reservoir amount can be sufficiently increased. Can be secured. Furthermore, by providing the through hole 20a in the cage 20, circulation of the grease G inside the lower bearing 6 is promoted. For this reason, the lower bearing 6 is maintained in a stable and good lubrication state, and does not become poorly lubricated. Damage (wear and seizure) due to friction can be effectively prevented. Further, a sufficient amount of lubricant G (for example, grease) can be stored in the lubricant storage portion 20c for a long period of time, and for example, the base oil can be oozed out of the grease G. It is possible to more effectively prevent the raceway surfaces of the inner and outer rings 6a, 6b and the rolling surfaces of the rolling elements (balls) 6c from being damaged (weared or burned).

  In this case, the method for enclosing the lubricant G (for example, grease) G in the lower bearing 6 is not particularly limited, but the grease G is easily attached and stored in the lubricant storage portion 20c of the cage 20. The grease G is preferably sealed in the lubricant reservoir 20c from the opening 20k side of the cage 20 through the through hole 20a. Further, when assembling the lower bearing 6, the grease G may be sealed in advance in the lubricant reservoir 20c of the cage 20.

  As described above, according to the present embodiment, in a state where the lower bearing 6 supports the main shaft 2 (FIG. 2A) of the submersible pump, the cage 20 is attached to the lower bearing 6 and the opening 20 k is the upper side in the vertical direction. As a result, the lubricating performance of the lower bearing 6 can be kept constant over a long period. As a result, the lower bearing 6 can maintain a constant rotational accuracy over a long period of time and exhibit excellent durability. Therefore, for example, even when the mechanical seal 18 is worn, the lower bearing 6 is immediately abnormal (for example, wear or seizure of the raceway surfaces of the inner and outer rings 6a and 6b and the rolling surfaces of the rolling elements (balls) 6c). Will not occur. In this case, since the submersible pump can be operated with a constant rotational accuracy for a long period of time (long life) by simply replacing the mechanical seal 18, the cost can be reduced.

  In the above-described embodiment, the size of the lower bearing 6 is not particularly mentioned, but the size is, for example, the size of a vertical shaft device (for example, a submersible pump) in which the bearing 6 is used. Any setting may be made according to the above. As an example, in this embodiment, the outer diameter of the bearing is set to 62 mm, the inner diameter of the bearing is set to 30 mm, and the bearing width is set to 16 mm.

  Further, in the above-described embodiment, the type (component) and the amount of the lubricant G to be enclosed in the lower bearing 6 are not particularly mentioned. However, the predetermined type of lubricant is arbitrarily given by a predetermined amount. What is necessary is just to enclose. As an example, in the present embodiment, a grease G is applied in which the thickener is urea, the base oil is a synthetic hydrocarbon oil, the kinematic viscosity at 40 ° C. is 48 square millimeters per second, and the penetration is 250. G was enclosed by an amount of 25% of the bearing space volume of the lower bearing 6. In this case, the type of thickener of the grease G is not particularly limited, and in addition to urea, for example, lithium soap, sodium soap, bentonite, PTFE (tetrafluoroethylene resin) and carbon black are applied. Also good. Similarly, the type of base oil of the grease G is not particularly limited, and for example, ester oil, ether oil, fluorine oil, silicone oil, mineral oil, and the like may be applied in addition to the synthetic hydrocarbon oil.

Furthermore, in the above-described embodiment, as an example, the cage 20 made of PA (polyamide) is applied, and the material thereof is a material obtained by adding 25% glass fiber as a reinforcing fiber to PA66 (polyamide 66). It was used. In this case, the type of the basic material is not particularly limited. In addition to PA66 (polyamide 66), for example, PA46 (polyamide 46), PPS (polyphenylene sulfide), polyimide, PEEK (polyetheretherketone), and the like are applied. May be. Similarly, the type and amount of reinforcing fiber added to the base material are not particularly limited.
In the above-described embodiment, the cage 20 provided with the through hole 20a and the lubricant reservoir 20c is incorporated only in the lower bearing 6, but the cage is attached to the upper bearing 8 in addition to the lower bearing 6. 20 may be incorporated.

Here, the lubrication performance of the rolling bearing according to the present embodiment was verified by performing a test. The test contents and test results will be described below.
In the test, two rolling bearings were prepared as samples, and one of the rolling bearings was provided with a through-hole 20a and a lubricant reservoir 20c (a cage 20 shown in FIG. The present cage 20)) was assembled between the inner and outer rings (hereinafter, the bearing is referred to as the present bearing). On the other hand, the other rolling bearing is not provided with a through-hole, and is provided with a cage (only a cage 50 shown in FIG. 5A (hereinafter referred to as a comparative cage 50)) provided with only a lubricant reservoir 20c. It was assembled between the inner and outer rings (hereinafter, this bearing is referred to as a comparative bearing).

  FIG. 3 (a) shows a test machine for verifying the lubrication performance of the rolling bearing A. Using the test machine, the bearing and the comparative bearing (rolling bearing A) are subjected to a predetermined condition. The bearings were tested for lubrication performance by comparing the amount of lubricant encapsulated in the inside of both bearings on the sealing plate and the cage. In the verification, the bearing and the comparative bearing (rolling bearing A) were set to have a bearing outer diameter of 62 mm, a bearing inner diameter of 30 mm, and a bearing width of 16 mm. The bearing A (the bearing and the comparative bearing) is provided with a mounting groove for mounting the sealing plate 36 (contact type rubber seal) in the outer ring 32, and a contact groove for contacting the tip (lip) of the seal 36. Provided on the inner ring 30, one seal 36 is interposed between the inner and outer rings 30 and 32 (upper and lower sides in FIG. 3). Further, as the retainer 34 (the present retainer 20 and the comparison retainer 50), a PA66 (polyamide 66) crown-shaped retainer is applied, and the retainer 34 has an opening side in a predetermined direction (upper side in FIG. 3). It was installed between the inner and outer rings 30, 32 so that 3A shows, as an example, a test state of a bearing A (present bearing) in which the present retainer 20 is incorporated between the inner and outer rings 30 and 32 as the retainer 34. FIG.

  In the test, the following work was performed as a pretreatment. First, the rolling bearing A (the bearing and the comparative bearing) is washed with hexane, and the weight (weight X) of the washed bearing body (inner and outer rings 30, 32, rolling elements (balls) 38 and cage 34), and The individual weights (weight U) of the two rubber seals 36 attached to each bearing body were measured. Next, 2 grams of grease as a lubricant was sealed on the opening side of the cage 34 (the present cage 20 and the comparative cage 50), and two seals 36 were attached to the bearing A after the lubricant was sealed. The total weight of the bearing body (inner and outer rings 30, 32, rolling elements (balls) 38 and cage 34), seal 36 and grease was measured for each of the present bearing and the comparative bearing.

  Such a rolling bearing A (the present bearing and the comparative bearing) is externally fitted to the main shaft 40, and is fitted into the housing 42 into the test apparatus, and the main shaft 40 is rotated for 16 hours at a speed of 3000 rotations per minute. I let you. In this case, an axial load of 49 Newton is applied to the rolling bearing A (the present bearing and the comparative bearing), and the temperature of the internal space of the testing machine in which the bearing A is incorporated becomes room temperature during the test. It was adjusted.

After the test is completed, the rolling bearing A (the bearing and the comparative bearing) is removed from the main shaft 40. First, the total weight of the bearing A (bearing body (inner and outer rings 30, 32, rolling elements (balls) 38 and cage 34), seal) 36 and the total weight of grease) (weight Y) were measured for each of the present bearing and the comparative bearing. Next, the two seals 36 were removed from the bearing A (the present bearing and the comparative bearing), and the weight (weight Z) of the two seals 36 was measured for each of the present bearing and the comparative bearing. In this case, for the two seals 36, the weight (weight V) on one side (upper side in FIG. 3) and the weight on the other side (lower side in FIG. 3) were individually measured. For the bearing A (the bearing and the comparative bearing), the amount of grease adhering to the upper seal 36 (the amount of adhering upper seal grease (W1)) is calculated from the weight (weight V) of the seal 36 after the test before the test. Was calculated as a value obtained by subtracting the weight (weight U) (W1 = V−U). For bearing A (this bearing and comparative bearing), the amount of grease adhering to the vicinity of the cage 34 (the amount of grease adhering to the cage (W2)) was tested from the total weight (weight Y) of the bearing A after the test. The weights (weight Z) of the latter two seals 36 and the weight (weight X) of the bearing body before the test were subtracted from each other (W2 = Y−Z−X).
In addition, the test mentioned above was performed 5 times each about this bearing and the comparison bearing.

FIG. 3B shows the result of the above-described test. As shown in FIG. 3B, in the comparative bearing, the upper seal grease adhesion amount (W1) was 0.6 during the five tests. The case of -0.9 gram was twice, and the case of 0.3-0.6 gram was three times, and the adhesion amount was not stable. Also, the grease adhesion amount (W2) in the vicinity of the cage was in the range of 1.2 to 1.3 grams.
On the other hand, regarding the present bearing, the upper seal grease adhesion amount (W1) was in the range of 0.3 to 0.6 gram. Also, the grease adhering amount (W2) in the vicinity of the cage was 1.3 g or more in all cases.

As described above, the present bearing has both the upper seal grease adhesion amount (W1) and the cage vicinity grease adhesion amount (W2) stable, and the upper seal grease adhesion amount (W1) is smaller than that of the comparative bearing. The amount of grease adhering to the cage (W2) was large. In other words, this bearing can be confirmed to have high lubrication efficiency because most of the grease (about 65% by weight) in the bearing keeps adhering (staying) stably in the vicinity of the cage over a long period of time. It was.
As described above, according to the present bearing incorporating the retainer 34 (the present retainer 20) provided with the through-hole 20a and the lubricant reservoir 20c, the retainer 34 (the comparative retainer 50) provided with only the lubricant reservoir 20c. Compared with a comparative bearing incorporating a roller, for example, it is possible to effectively prevent damage (wear and seizure) due to friction between the raceway surfaces of the inner and outer rings 30 and 32 and the rolling surface of the rolling elements (balls) 38, for a long time. Through the above test, it was verified that a constant rotational accuracy can be maintained over a long period of time and excellent durability can be exhibited.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the structural example of the cage for rolling bearings concerning one Embodiment of this invention, Comprising: (a) is a top view which shows some cages seen from the opening side, (b) is sectional drawing. (C) is a perspective view which shows the whole holder | retainer, (d) is sectional drawing which shows the lubrication state of the lubricant enclosed with the bearing. (a) is sectional drawing which shows the structural example of the submersible pump which concerns on one Embodiment of this invention, (b) is sectional drawing which shows the structural example of the rolling bearing used for the submersible pump. It is a figure for demonstrating the verification test of the lubrication performance of a rolling bearing, Comprising: (a) is sectional drawing which shows the structural example of the principal part of a testing apparatus, (b) is a figure which shows a test result. Sectional drawing which shows the structural example of the principal part of the conventional submersible pump. It is a figure which shows the structural example of the conventional cage for rolling bearings, Comprising: (a) is a perspective view which shows the whole holder | retainer, (b) is sectional drawing which shows the lubrication state of the lubricant enclosed with the bearing.

Explanation of symbols

2 Spindle 4 Electric motor 6, 8 Rolling bearing 10 Impeller 18 Mechanical seal 20 Cage 20a Through hole 20c Lubricant reservoir 20h Column 20k Opening 20p Pocket 20t Claw 22 Sealing plate G Lubricant M Motor part P Pump part S Oil Room

Claims (3)

A plurality of pockets for holding a plurality of rolling elements one by one and a plurality of pillars connecting adjacent pockets are provided along the circumferential direction, and an opening for inserting the rolling elements into the pocket is provided on one side. A rolling bearing retainer having the other side closed,
The column portion is provided with at least one through hole for allowing a lubricant to lubricate the rolling bearing to flow, and the through hole is formed to penetrate from one side of the column portion to the other side. A cage for a rolling bearing characterized by that.   At least one lubricant reservoir for storing lubricant is provided on the other side of the rolling bearing retainer, and the lubricant reservoir is formed in communication with the through hole. The cage for a rolling bearing according to claim 1. An electric motor that rotates a main shaft that extends in the vertical direction, a motor unit that houses a plurality of rolling bearings that rotatably support the main shaft, and a pump unit that contains an impeller attached to the lower end side of the main shaft An oil chamber located between the motor unit and the pump unit and provided with an oil chamber in which a mechanical seal for keeping the motor unit airtight is installed in a vertical direction,
The rolling bearing cage according to claim 1 or 2 is used for a rolling bearing disposed at least near the oil chamber, and the rolling bearing is incorporated between a pair of race rings and the race rings so as to be freely rollable. A plurality of rolling elements, and the rolling bearing retainer is incorporated between the bearing rings with the opening facing upward in the vertical direction in a state where the rolling bearing supports the main shaft. Submersible pump characterized by

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