JP2014020526A - Rolling bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rolling bearing which prevents that the bearing is damaged by a shock during rotation to cause abnormal vibrations on the bearing and a spacer falling, in a spacer type solid lubrication bearing in which the spacer made of solid lubrication material is arranged between rolling bodies with respect to the rolling bearing used in an environment of high temperature, high vacuum or the like.SOLUTION: A solid lubrication rolling bearing includes an inner ring 2, an outer ring 1, a rolling body 3, a spacer 4 containing a solid lubricant made of selected material and a retainer 5 having pockets which store the spacer and the rolling body by setting at least one spacer 4 and one rolling body 3 as a unit. Thereby, the solid lubrication rolling bearing which has no risk of falling or breakage, hardly causes vibrations and can obtain smooth and safe rotations is provided.

Description

  The present invention relates to an improvement in a self-lubricating solid-lubricated rolling bearing used in an environment such as high temperature, vacuum, or vacuum high temperature where grease lubrication cannot be used.

  Conventionally, solid lubrication type bearing lubrication has been performed for rolling bearings used in environments such as high temperature, high vacuum, or high vacuum temperature where grease lubrication, which is a general bearing lubrication method, cannot be used. In this conventional solid-lubricated rolling bearing, it was initially considered that a crown type cage was made of a solid lubricating material to serve as a lubricant supply source. However, the solid lubricating material is very brittle and sometimes cracks or breaks during assembly of the bearing. In view of this, a spacer type solid lubricating bearing in which the cage is separated and disposed between the rolling elements has been considered. Various methods for assembling spacers in this spacer type solid lubricated bearing have been proposed. For example, Japanese Patent Application Laid-Open Nos. 7-151152 and 9-144760 disclose insertion cuts provided on a part of the bearing. A method of inserting a spacer from a notch is disclosed. Japanese Patent Laid-Open No. 8-4773 discloses a method of inserting a cylindrical spacer vertically between the inner and outer rings in a roller bearing and sealing the inner and outer rings with a shield.

  Moreover, in the actual Japanese Utility Model Publication No. 7-21927, a concave portion serving as a pocket capable of accommodating at least two rolling elements is formed, and a graphite spacer is interposed between the rolling elements accommodated in each pocket. A rolling bearing cage is disclosed. Other related patent documents include JP-A-8-004773, JP-B-07-021927, JP-A-63-035817, JP-A-55-099332, JP-A-01-261516, JP-A-Hei. No. 02-146314, Japanese Utility Model Laid-Open No. 03-003699, Japanese Utility Model Laid-Open No. 05-032831, Japanese Utility Model Publication No. 36-019806, Japanese Patent Application Laid-Open No. 02-021027, Japanese Utility Model Application Laid-Open No. 04-082432, Japanese Patent Application Laid-Open No. 08-2322961, and the like. .

Japanese Patent Laid-Open No. 07-151152 JP 09-144760 A JP-A-8-004773 No. 07-021927 Japanese Utility Model Publication No. 63-035817 JP-A-55-099332 JP-A-01-261516 Japanese Patent Laid-Open No. 02-146314 Japanese Utility Model Publication No. 03-003699 Japanese Utility Model Publication No. 05-032831 Japanese Utility Model Publication No. 36-019806 Japanese Patent Laid-Open No. 02-021027 Japanese Utility Model Publication No. 04-082432 Japanese Patent Laid-Open No. 08-232961

  In the spacer type solid lubricated bearing, as disclosed in the above publication, the spacer is provided with a notch for inserting a spacer in order to incorporate the spacer. The spacers caught on the notches obstructed rotation, and abnormal vibrations sometimes occurred. In particular, when an axial load is generated on the bearing, the rolling surface approaches the notch, so that abnormal vibration is likely to occur, and in some cases, the spacer may drop off.

  Also, if all the solid lubrication spacers are inserted between the rolling elements, the number of spacers required per bearing increases, which not only increases the cost, but also the circumferential impact generated on the spacers during rotation. There is a problem that the force becomes large and causes damage to the spacer.

  In particular, even when a special cage is used, when a material mainly composed of graphite is used as a spacer inserted between rolling elements, the spacer wears quickly and the circumferential clearance in the cage Since the increase in the temperature becomes remarkable, there is a problem that a sufficient life extension effect cannot be obtained. Further, in applications where a high load is applied to the spacer, the spacer may be broken, and there is a problem in reliability. Further, since the lubrication performance of graphite deteriorates in a vacuum, the bearing life is limited when used in vacuum applications.

Therefore, the present invention does not hinder the rotation due to the spacer being caught, the spacer does not fall off, the vibration is low, and a highly reliable and low-cost solid-lubricated rolling that provides smooth and safe rotation. An object is to provide a bearing.
The present invention relates to a solid lubricated rolling bearing capable of achieving such an object.

  The solid-lubricated rolling bearing of the present invention includes an inner ring, an outer ring, a rolling element, a spacer made of a material containing a solid lubricant, and a pocket that stores at least one of the spacer and one rolling element as a unit. A cage having a curvature that holds the rolling elements and the spacer in both the vertical direction and the circumferential direction of the rolling bearing, and the spacer has a base at least at one end of a cylindrical base. It is a shape which has a substantially cylindrical part with a diameter smaller than the diameter of.

  With this configuration, the solid lubricated rolling bearing of the present invention does not require a notch for incorporating a spacer. Therefore, the processing cost of the conventional notch portion can be suppressed and the cost is low, and the inserted spacer is not caught by the notch portion and the rotation is not inhibited, so that abnormal vibration does not occur. Further, since the inserted spacer is restrained by the rolling element from at least one side, preferably from both sides, there is no possibility that the spacer is detached from the raceway grooves of the inner and outer rings due to vibration or the like. Moreover, regarding the lubrication function, all the rolling elements are in contact with the spacer containing the solid lubricant in at least one place, and the solid lubricant moves onto the contact surface of the rolling element and adheres (transfers). Sufficient lubrication performance can be obtained by the solid lubricant.

  Further, in the solid lubricated rolling bearing of the present invention, the cage is a cage that holds the two spacers as a unit with the spacer interposed therebetween, so that the number of spacers is reduced with respect to the number of rolling members. The cost can be reduced by halving, and two rolling elements and one spacer are housed in the cage pocket as a unit. Therefore, compared to the conventional combination of the same number of rolling elements and spacers, this occurs in the spacer during rotation of the bearing. The impact force in the circumferential direction is reduced, and spacer damage is suppressed.

  Further, in the solid lubricated rolling bearing of the present invention, the spacer includes a cylindrical base portion and a cylindrical portion having a diameter smaller than a base diameter provided at least at one end portion thereof. The cylindrical portion having a diameter smaller than the base diameter is also referred to as a so-called land portion. Due to the presence of the land portion, even if the spacer is relatively long in the circumferential direction, it can be incorporated into the bearing while suppressing the breakage and cracking of the spacer. Here, the spacer may have land portions on both sides, and one side may be a flat surface, a convex surface, or a concave surface. Further, the corner portion of the previous spacer may be chamfered to prevent cracking and chipping.

  Preferably, the cage is a cage that holds two rolling elements with the spacer interposed therebetween, and the pocket of the cage is in the vertical direction of the rolling bearing (the direction perpendicular to the rotating shaft of the rolling bearing). And a curvature that holds the rolling elements and the spacers in both the circumferential direction and a solid lubricating film similar to the spacers is formed on at least the surface of the rolling elements. By adopting such a configuration, the number of spacers can be reduced and costs can be reduced compared to conventional rolling bearings in which solid lubricant spacers are all interposed between the lubricating rolling elements, and the rotation of the rolling bearings is further reduced. The impact force in the circumferential direction generated in the spacer can be reduced, and the risk of spacer damage can be reduced. In addition, in a structure having a pocket for accommodating one spacer and two rolling elements, the rolling element and the spacer can be held by curved surfaces in both the vertical direction and the circumferential direction of the rolling bearing, and held during rotation of the rolling bearing. The machine position is fixed (the vertical and circumferential positions of the rolling bearings are kept constant), and the center axis of the spacer and the rolling element can be kept substantially constant, allowing torque fluctuations and vibrations even when the spacer is worn. Can be suppressed over a long period of time. Furthermore, at the initial stage of rotation of the rolling bearing, even if the solid lubricant is not sufficiently transferred from the spacer made of the solid lubricant to the rolling elements, an immediate and sufficient lubricating performance can be obtained to obtain the rolling bearing. Long life can be achieved.

  Preferably, in the solid lubricated rolling bearing of the present invention, the size of the circumferential clearance of the pocket of the cage is within a range of 0.01 mm to 20% of the rolling element diameter. The rotational torque of the bearing, the starting torque, and the vibration of the cage can be effectively suppressed.

  Preferably, in the solid lubricated rolling bearing of the present invention, the diameter of the spacer is 0.50 to 0.95 times the diameter of the rolling element, thereby suppressing rotational torque and causing uneven wear. In addition, the vibration level can be kept low.

  Furthermore, preferably, in the solid lubricated rolling bearing of the present invention, the radius of curvature of the contact surface of the cage pocket with the rolling element is set to 1.01 to 1.10 times the rolling element radius. Thus, the clearance between the cage and the rolling element is made appropriate to prevent vibration of the cage.

  In the solid lubricated rolling bearing of the present invention, the material of the spacer is molybdenum disulfide, tungsten disulfide, or boron nitride, or molybdenum disulfide and tungsten disulfide as a main component of the lubricant. The lubricant component is a metal selected from iron, copper, nickel, tungsten, tin, cobalt, chromium (Fe, Cu, Ni, W, Sn, Co, Cr) or an oxide, nitride, boride thereof, and baked. By using a self-lubricating sintered composite material obtained by bonding, generation of excessive wear powder and cracking of the spacer can be prevented.

  In particular, the self-lubricating pillar-sintered composite material in which the lubricant component mainly composed of molybdenum disulfide (MOS2) and tungsten disulfide (WS2) is 80% or less and the balance is an iron-based alloy is mainly composed of graphite. It is stronger than the conventional one, has an appropriate amount of wear, and can be used in the air or in a vacuum, and is suitable for the bearing of the present invention. However, when the bearing of the present invention is used at a temperature of 350 ° C. or higher, a self-lubricating sintered composite material in which a lubricant mainly composed of boron nitride and a nickel alloy are combined is preferable as the spacer material.

  The solid lubricating rolling bearing of the present invention can be suitably used as an axle bearing for a kiln car used at high temperature and low speed, for example. In this case, in the solid lubricated rolling bearing of the present invention, the inner ring is used as a rotating ring. Further, it can be suitably used for a bearing for a tenter clip of a film stretching apparatus. In this case, the outer ring is used as a rotating wheel.

  Furthermore, in applications where so-called rigidity is required for rolling bearings, it is possible to use the bearings with a preload.

  In addition, the solid lubricated rolling bearing of the present invention only needs to have three or more rolling elements in one bearing, and in a so-called thin bearing having a small dimensional difference between the inner ring inner diameter and the outer ring outer diameter, a thin cage The rolling elements and spacers can be downsized and a large number can be arranged in the bearing.

  In the solid lubricated rolling bearing of the present invention, the type of the bearing is arbitrary and can be applied to a cylindrical roller bearing, an angular ball bearing and the like. A combination of bearings is also arbitrary, and a cylindrical roller bearing or the like and a deep groove ball bearing or the like can be used in combination as necessary. Furthermore, in the solid lubricating roller bearing of the present invention, a sealing seal or a shield plate can be attached as necessary. Moreover, the width | variety etc. of an inner-outer ring | wheel can be suitably selected according to use conditions. The same applies to the rolling element PCD and the like. In addition to the raceway surface, a solid lubricant film may be formed on the rolling elements and the cage in advance.

These are the perspective views which notched and represented some solid lubrication rolling bearings of this invention. FIG. 2 is a front view of a bearing retainer shown in FIG. 1. FIG. 2 is a partially enlarged view of the cage of FIG. 1. FIG. 4 is a side view of one side of the cage shown by the arrow IV in FIG. 2. (A) is a perspective view of the conventional spacer. (B) is a perspective view of the spacer of the present invention. These are figures explaining the mounting procedure of a spacer. These are the flowcharts which show the dimension determination method of a spacer. These are the geometrical figures for calculating | requiring the dimension calculation formula of a spacer. These are the geometrical figures for calculating | requiring the pocket clearance dimension calculation formula of the circumferential direction of a spacer. These are the geometrical figures for calculation of the chamfer dimension of a spacer. These are structure explanatory drawings of a comparative example. These are structure explanatory drawings of a comparative example. These are structure explanatory drawings of a comparative example.

1 outer ring, 2 inner ring, 3 rolling elements, 4 spacer, 5 cage

The present invention will be described in more detail with reference to the drawings.
1 to 5 show a solid-lubricated deep groove ball bearing which is an embodiment of a solid-lubricated rolling bearing according to the present invention. FIG. 1 is a perspective view with a part cut away, and FIG. FIG. 3 is a partially enlarged view of the cage, FIG. 4 is a side view of one side of the cage shown by the arrow IV in FIG. 2, and FIG. 5 is a perspective view of the spacer. In this ball bearing, eight rolling elements (in this case, balls) 3 are disposed between the outer ring 1 and the inner ring 2 at a predetermined interval in the circumferential direction. Two balls 3 are made into one set, and are housed in a pocket 51 of a cage 5 together with one spacer 4 interposed therebetween to form one unit.

  As shown in FIG. 5, the spacer 4 has a cylindrical shape, and the diameter ds is larger (h <ds) than the width (or height) h between both end faces 41, 41, and the diameter ds will be described later. Thus, the bearing inner and outer rings 1 and 2 are designed in accordance with the shape of the raceway surface, and the corners of the end surface 41 are chamfered. The chamfer 42 facilitates the insertion work of the spacer 4, and the chamfer dimension x is calculated using a mathematical formula described later. In the illustrated example, the chamfer 42 is a chamfer chamfer, but it may be an R chamfer. In addition, the entire circumference of the corner portion of the end surface 41 is chamfered, but the present invention is not limited to this, and a part of the corner portion of the both end surfaces 41, 41 may be chamfered on at least one diagonal line of the spacer 4. However, a part that is chamfered must be aligned with the inner and outer ring surfaces when inserted into the bearing, so the insertion work becomes cumbersome, and if the corner remains, the part is easily damaged. It is preferable to chamfer the entire circumference as much as possible. In addition, in order to reduce the number of processes during the creation of the spacer, the insertion of the spacer can be facilitated by setting the diagonal length of the spacer to the conditions described later when chamfering is not performed. However, in this case as well, it is desirable that the spacer corners be processed to the level of thread chamfering to prevent microfracture.

  The spacer 4 is made of a material having a solid lubricating function. Specifically, the spacer 4 is made of natural or artificial graphite material, boron nitride, molybdenum disulfide, tungsten disulfide, or the like, glass fiber, heat resistant Mixed with reinforced fillers such as water-soluble resin fibers and carbon fibers, solidified with organic or inorganic binders and fired, or combined sintered with the above-mentioned solid lubricating materials and heat-resistant alloys such as iron, nickel and cobalt Can be considered.

  In the structure of the solid lubricated rolling bearing according to the present invention, when excessive wear powder or lump-shaped pieces are caught between the outer / inner rings 1, 2, the rolling elements 3, and the cage 5, the bearing vibration value increases. Becomes unrotatable. Further, when the spacer is cracked due to impact or compression caused by the collision of the rolling elements during rotation, the bearing locks and stops suddenly, which may adversely affect the apparatus to which the bearing is attached. In particular, in applications where rotational accuracy is required, the internal clearance must be reduced to the limit and is particularly sensitive to excess massive wear powder. Further, with respect to a bearing used under high temperature and high load conditions, since the load on the spacer 4 is increased, the possibility that the spacer 4 will break increases. As a countermeasure against these problems, it is conceivable to increase the strength of the spacer 4, but a solid lubricant mainly composed of graphite is not suitable because it is generally brittle and easily worn (compressive strength of about 10 MPa).

  In contrast, the self-lubricating sintered composite material in which the lubricant component mainly composed of molybdenum disulfide and tungsten disulfide is 80% or less and the balance is an iron-based alloy has high strength (compressive strength of about 140 MPa). The amount of wear is also appropriate. Further, since it can be used without any problem in the air or in a vacuum, it is suitable for the bearing of the present invention. However, since molybdenum disulfide is oxidized from around 350 ° C. and the lubrication characteristics deteriorate, when the bearing of the present invention is used at a temperature exceeding this, a lubricant mainly composed of boron nitride and a nickel alloy are combined. Self-lubricating sintered composite materials can be used effectively.

  When the lubricant component exceeds 80%, the metal matrix is not sufficiently strengthened, the material strength is deteriorated, and the wear amount is increased. For this reason, the amount of the lubricant component is preferably 80% or less, particularly about 40 to 60%.

  In the illustrated case, the retainer 5 is a press-type retainer, and has two arcuate pockets 51 that are accommodated by sandwiching two balls and one spacer 4 as a unit. A pair of annular press-formed metal plates 511 and 511 are combined to face each other, and the connecting portions 52 between the four pockets 51 are crimped with rivets 6 and fastened together. However, the fastening means is not limited to the rivet 6 and may be a push-back type fastening generally used in a cage of a small diameter bearing. Each of the four pockets 51 of the annular formed metal plates 511 and 511 has two ball storage portions 512 and 512 each having a curved surface that matches the spherical surface of the ball 3 at both ends of the pocket. A spacer accommodating portion 513 is formed in the middle of the curved surface so as to match the cylindrical surface of the spacer 4.

  In the solid lubricated rolling bearing retainer of the present invention, for example, it has a shape having a pocket for accommodating one spacer and two rolling elements, but it is constant in the vertical direction and the circumferential direction. It is desirable to have a structure that holds the rolling elements and the spacer with a curved surface having a curvature radius of. Thus, by holding the rolling elements and the spacers with curved surfaces, the position of the rotating cage can be fixed, and the central axes of the spacers and the rolling elements can be kept substantially constant, so that stable rotation can be maintained over a long period of time.

At this time, it is preferable that the curvature of the cage is 1.01 to 1.10 times the rolling element diameter in both the vertical direction and the circumferential direction. When the curvature is 1.01 times or less that of the rolling element, the efficiency of discharging the lubricant from between the cage and the rolling element is deteriorated, and an appropriate lubrication state cannot be maintained.
If the curvature is too large, the center axis of the spacer and the rolling element may not be displaced, and the cage may come into contact with the outer and inner ring end faces. Even in this case, the rotation of the bearing is maintained, but this is not preferable because it causes torque fluctuation and vibration. In order to easily implement an appropriate radius of curvature, it is desirable to use a press type cage. For applications requiring cage strength, a cage obtained by surface treatment such as nitriding or grinding is used.

  Further, when the bearing having an odd number of rolling elements in the basic design specification is a solid lubrication structure described in the present invention, one of the cage pockets contains one rolling element and one spacer, or Although it is conceivable that three rolling elements and two spacers are alternately accommodated, in these cases, the cage shape is not uniform in the circumferential direction, which may impair the rotational stability of the bearing. .

  Therefore, only when the load bearing performance of the shaft is satisfied, the number of rolling elements is reduced to make the odd number an even number, so that all pockets have a shape that accommodates two rolling elements and one spacer. In this case, if the rolling elements are evenly arranged on the circumference, the distance between the rolling elements increases, and the clearance in the circumferential direction increases when the spacer is inserted. It is necessary to adjust the circumferential clearance.

  Here, it is desirable that the initial circumferential clearance be determined in the range of 0.01 mm to 20% of the rolling element diameter. When the circumferential clearance becomes negative, the spacer presses and restrains the rolling element against the cage, so that the bearing cannot rotate. If the initial circumferential clearance is positive but less than 0.01 mm, the two rolling elements sandwiching the spacer interfere with the cage pocket and increase the initial torque. The rolling element and the spacer are stretched in the cage pocket due to the biting, and the bearing is locked. On the other hand, if the clearance exceeds 20% of the rolling element diameter, in addition to promoting rotational vibration due to the collision between the rolling element and the spacer, the spacer may easily fall over and inhibit rotation of the bearing. Therefore, as described later, the total clearance δ is selected from δ = 0.01 mm to 20% of the rolling element diameter.

The procedure for assembling the bearing constructed as described above is as follows.
It is assumed that eight balls 3 are already incorporated between the outer ring 1 and the inner ring 2.
(1) Collect the balls 3 at one place on the circumference of the bearing.
(2) One spacer 4 is inserted into the blank spacer S between the inner and outer rings generated by collecting the balls 3. At that time, first, as shown in FIG. 6A, both end surfaces 41 of the spacer 4 face the outer ring inner diameter surface 11 that is the guide surface of the outer ring 1 and the inner ring outer diameter surface 21 that is the guide surface of the inner ring 2. Insert it like this. Next, as shown in FIG. 6B, the spacer 4 is rotated along the groove surface 12 of the outer ring 1 and the groove surface 22 of the inner ring 2 so that both end surfaces 41 of the spacer 4 are directed in the circumferential direction of the bearing. Make it go.
(3) The two balls 3 are moved toward the opposite end from any one end side of the row of balls collected in one place, and come into contact with one end face 41 of the spacer 4 into which the one ball 3 is inserted. Let The other end face 41 of the spacer 4 abuts on the ball 3 on the opposite side. Thus, one spacer 4 is in contact with the two balls 3 and sandwiched.
(4) The above steps (2) and (3) are repeated until there are no balls 3 in contact with the spacer 4 (four times in the illustrated example).
(5) Unit groups (four groups) composed of two balls 3 and one spacer 4 sandwiched between them are aligned so as to be evenly distributed in the bearing circumferential direction.
(6) Two annular press-formed metal plates 511 and 511 (see FIG. 2) of the cage 5 are inserted into the gaps between the inner and outer rings from both sides of the bearing, and each unit group is placed in each pocket 51. Store.
(7) The connecting portion 52 of the cage 5, which is a butt portion between the two formed metal plates 511 and 511, is swaged with the rivet 6 and fastened together.

  Below, the determination method of the dimension of the spacer 4 in a prior art example is demonstrated based on the flowchart of FIG.

  Since the spacer 4 can be inserted without providing a spacer insertion notch in a part of the inner and outer rings as in the prior art and does not fall off after insertion, the dimensions of each part are related to the dimensions of the inner and outer rings. Determine as follows.

Step 1: Determination of Diameter ds of Cylindrical Spacer 4 The diameter ds of the spacer 4 should basically be smaller than the diameter dw of the rolling element 3. However, if the diameter is extremely small, it will be easy to drop off from the raceway surface, so about 90% of the diameter dw of the rolling element 3 is used as a reference.
That is, the reference diameter ds of the spacer is preferably about 0.90 dw, but can be adjusted in a range of 0.95 to 0.5 times the rolling element diameter. If the spacer diameter exceeds 0.95 times the rolling element diameter, not only will assembly be difficult, but the corners of the spacer will interfere with the outer / inner ring transfer surface during rotation, and it will be easy to generate massive wear powder due to microfracture. . The generated abrasion powder is caught between the rolling elements and the outer / inner ring during rotation, causing torque fluctuation and increased vibration. On the other hand, if the ratio is less than 0.5 times, the rolling element cannot pinch the spacer at the equator portion, and this may cause rotation failure of the bearing due to problems such as uneven wear of the spacer and riding on the spacer of the rolling element.
Therefore, the spacer diameter ds = (0.95 to 0.5) × dw.

Step 2: Determination of the height (or width) h of the cylindrical spacer 4:
Dw; diameter Dg of rolling element 3: diameter of outer ring guide surface 11 (outer ring inner diameter)
dg: Diameter of inner ring guide surface 21 (outer diameter of inner ring)
ds: Spacer 4 diameter h: Spacer height (or width)
Dr: Diameter of the outer ring groove 12 dr: Diameter of the inner ring groove 22 x: Chamfer dimension on the diagonal of the spacer.

スペーサ４の高さｈは、外輪内径Dg及び内輪外径ｄｇから、この（４）式で求める。 The height h of the spacer 4 is required to pass through a gap S between the outer ring 1 and the inner ring 2. From FIG. 8 [state of FIG. 6A], Δh + h = (Dg / 2) − (dg / 2) (1)
Also,
Δh = (Dg / 2) − (Dg / 2) cos (θ / 2) (2)
Also,

The height h of the spacer 4 is obtained from the outer ring inner diameter Dg and the inner ring outer diameter dg by the equation (4).

の和δ=δ１+δ２で得られる。 Step 3: Checking the circumferential clearance in the cage pocket Another constraint is that the clearance in the circumferential direction when sandwiched between two rolling elements and stored in the cage pocket is appropriate. There is a need. The clearance amount δ in the cage pocket changes due to wear of the spacer during rotation, but in the initial state, as shown in FIG. 9 (state of FIG. 6B).

Is obtained as δ = δ1 + δ2.

However,
δ1: Circumferential clearance between the rolling elements and the spacer δ2: Circumferential clearance between the rolling elements and the cage surface dw: Diameter of the rolling element dp: Pitch circle diameter of the bearing θ: Angle between the rolling elements α: Cage pocket Radius of curvature of contact surface with rolling element / radius of rolling element
h: The height of the spacer.
The angle θ between the rolling elements is an angle formed by both rolling elements sandwiching the spacer, and θ = 360 / Z when Z (even number) rolling elements are evenly arranged on the entire circumference 360 °.
It is obtained by. When Z is an odd number, θ differs by one.

  Α is a value obtained by dividing the circumferential radius of curvature of the cage pocket portion by the rolling element radius, and is set to about 1.01 to 1.10 (details will be described later). Therefore, δ2 is a positive value determined by the cage shape. Here, it is necessary to adjust the spacer height so that δ1 influenced by the spacer height does not become a negative value. This is because, when δ1 <0, the spacer presses the rolling element against the cage and restrains it, so that the bearing may not be able to rotate.

  As a result, the total clearance δ = δ1 + δ2 in the circumferential direction in the cage may not be 0, but actually, δ1 and δ2 are designed separately. Since δ1 is determined depending on the height h of the spacer, an appropriate value of δ1 (> 0) determines h.

  If the value of δ1 does not become positive, the process returns to step 2 to determine a new h by the equation (4), and again proceeds to step 3 to obtain δ1 by the equation (5) and confirm the positive / negative. When 0 <δ1 is confirmed, the process proceeds to the next step.

  Note that the circumferential clearance can be adjusted by adjusting the pocket size of the cage, but the circumferential arrangement of the rolling elements will be uneven. Is preferably performed at the spacer height.

Step 4: Determination of the dimension x of the chamfer 42 of the cylindrical spacer 4:
The chamfering of the spacer is mainly for the purpose of facilitating the spacer insertion operation, and therefore is not necessarily required as long as the conditions for the spacer diameter and length are strictly satisfied. However, the corners of the spacer are liable to cause micro-breakage due to contact with the rolling elements, and may generate massive wear powder. If a large amount of these agglomerated wear powders are bitten into the bearing, it will cause rotation failure, so it is desirable that the corners be treated to the level of thread chamfering.

The chamfer dimension x of the spacer 4 is a condition that the spacer 4 can rotate within the space between the outer ring groove surface 12 and the inner ring groove surface 22.
From FIG. 10, since the length (h2 + ds2) 1/2 of the diagonal line L1 of the spacer 4 is the longest and the chamfering 42 is performed on the line, if the chamfering dimension that can be rotated is x on one side, 2x = (H2 + ds2) 1 / 2- (Dr-dr) / 2
Ｘ x = (h2 + ds2) 1/2 / 2− (Dr−dr) / 4 (6)
The chamfer dimension x of the spacer 4 is obtained by the equation (6) from the diameter Dr of the outer ring groove surface 12, the diameter dr of the inner ring groove surface 22, the height h and the diameter ds of the spacer 4. The chamfer dimension x obtained in this way is a lower limit value in the calculation. If the chamfer dimension x is set slightly larger than this, the insertion operation of the spacer 4 is facilitated and the creation of the spacer 4 is facilitated.

As a calculation example, when applied to a single row deep groove ball bearing with a nominal number 6204,
Ball diameter dw: 7.938mm
Outer ring inner diameter Dg: 38.6. mm
Inner ring outer diameter dg: 28.5 mm
Outer ring groove diameter Dr: 41.4 mm
Inner ring groove diameter dr: 25.6 mm
As
Diameter ds of the cylindrical spacer 4 = 0.9 × 7.938 mm≈7.1 mm
When the height h of the cylindrical spacer 4 is obtained using the equation (4),

Further, when the chamfer dimension x (the radius of curvature on one side) is obtained using the equation (6),
x = (h2 + ds2) 1/2 / 2- (Dr-dr) / 4
= (4.72 + 7.12) 1/2 / 2- (41.4-25.6) / 4
= 0.3 (mm)
It becomes.

Step 5: Confirmation of rotation conditions when chamfering is not performed When chamfering is not performed, it is confirmed whether or not the spacer can be rotated in the space between the outer ring groove surface and the inner ring groove surface. As is apparent from FIG. 10, if the diagonal length L1 of the spacer 4 is smaller than the diameter dw of the ball 3 (L <dw), the outer ring. Can rotate in the groove space between the inner rings.

Therefore, in order to facilitate the rotation of the spacer 4, it is preferable to adjust the spacer size so that the diagonal length L1 of the spacer is about 1.1 to 0.7 times the rolling element diameter dw. That is, since the diagonal length L1 of the spacer is obtained by L1 = (ds2 + h2) 1/2,
1.1> L1 / dw> 0.7
Confirm that is true. 1.1 is an empirically acceptable upper limit, and when L1 exceeds 1.1 times dw, it becomes difficult to rotate the spacer and it becomes impossible to assemble. On the other hand, if the ratio is less than 0.7 times, the spacer may be easily dropped during rotation, which may hinder stable rotation of the bearing.
If the confirmation result of the rotation condition is out of the above range, the process returns to Step 1.

Since the solid lubricated rolling bearing of the conventional example configured as described above does not require a notch (insertion opening) for incorporating the spacer 4, the following various effects can be obtained.
(1) The processing cost of the notch (insertion opening) can be suppressed.
(2) Regardless of whether or not there is an axial load, the inserted spacer is not caught by the notch and does not hinder the rotation, so that abnormal vibration can be prevented.
(3) Since the inserted spacer is constrained by being pinched by rolling elements from both sides, there is no possibility that the spacer will come off from the raceway grooves of the inner and outer rings due to vibration or the like.
(4) The number of spacers can be halved with respect to the number of rolling elements, so the cost can be reduced, and two rolling elements and one spacer are housed in a cage pocket as a unit, so the same number of rolling elements and spacers are combined. Compared to the conventional one, the impact force in the circumferential direction generated in the spacer during rotation of the bearing is reduced, and damage to the spacer is suppressed. Moreover, regarding the lubrication function, all the rolling elements are in contact with the spacer containing the fixed lubricant at least at one place, and the solid lubricant is transferred to the contact surface of the rolling elements and attached (transferred). Sufficient lubrication performance can be obtained by the solid lubricant.

  Furthermore, in the solid lubricated rolling bearing of the present invention, as shown in FIG. 5B, since the land portion is provided in the spacer, it is easier to load than in the case of mere chamfering as in the conventional example. The risk of cracking and chipping during loading is further reduced. Furthermore, the total length of the spacer can be increased, leading to a longer life.

  The solid lubrication rolling bearing of the present invention is a rolling bearing in which a spacer containing a solid lubricant is sandwiched between rolling elements and solid lubrication is performed by transferring the solid lubricant to the rolling elements. Since the solid lubricant is not sufficiently transferred, a solid lubricant film similar to the spacer is applied to the rolling element or cage (entire surface), the sliding surface of the bearing race (for example, the outer diameter surface of the inner and outer rings) or the race surface. By forming a film, an initial lubricating effect can be achieved.

  Moreover, although embodiment demonstrated the single row deep groove ball bearing, this invention is applicable also to another ball bearing. Furthermore, the present invention is not limited to ball bearings, and can be freely applied to cylindrical, conical, and spherical roller bearings.

  Moreover, although the case where the press type | mold cage was used was demonstrated in embodiment, it is not restricted to this, For example, a crown type | mold, a punching type | mold, a punching type | mold etc. can be used.

  Further, in the embodiment, the description has been given of the cage having one spacer and a pocket for storing two rolling elements for an even number (e.g., eight) rolling elements, but an odd number of rolling elements. In this case, it is assumed that one of the cage pockets accommodates one rolling element and one spacer, or alternately accommodates three rolling elements and two spacers. That is, in summary, the solid lubricated rolling bearing of the present invention has a cage having a portion for accommodating at least one rolling element and one spacer, and if there are three or more rolling elements in total. good.

Claims (2)

In a solid lubricating rolling bearing comprising an inner ring, an outer ring, a rolling element, a spacer made of a material containing a solid lubricant, and a cage having a pocket for housing the rolling element and the spacer, the cage is the A holder for storing a spacer and at least one rolling element as a unit, and a pocket of the holder has a curvature for holding the rolling element and the spacer in both a vertical direction and a circumferential direction of the rolling bearing; A solid-lubricated rolling bearing characterized by having a shape having a substantially cylindrical portion having a diameter smaller than the diameter of the base at at least one end of the cylindrical base. In a solid lubricating rolling bearing comprising an inner ring, an outer ring, a rolling element, a spacer made of a material containing a solid lubricant, and a cage having a pocket for housing the rolling element and the spacer, the cage is the A cage which holds two rolling elements as a unit with a spacer interposed therebetween, and a pocket of the cage has a curvature for holding the rolling elements and the spacer in both the vertical direction and the circumferential direction of the rolling bearing, A solid-lubricated rolling bearing characterized by having a shape having a substantially cylindrical portion having a diameter smaller than the diameter of the base at at least one end of the cylindrical base.

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