JP2013036608A - Snap cage and rolling bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a snap cage which is hardly deformed and is suitable for use in high-speed rotation and high-temperature conditions, and to provide a rolling bearing which is hardly damaged even when being used in high-speed rotation and high-temperature conditions.SOLUTION: The snap cage 4 includes an annular main part 11 and a plurality of pockets 12 which are disposed in one axial-direction edge surface of the main part 11 and store balls rollably. Each pocket 12 is composed of a concave part 13 disposed in the edge surface of the main part 11 and a pair of prongs 14, 14 which are arranged opposite to each other leaving an interval in the edge of the concave part 13 so as to hold the concave part 13 from both circumferential-direction side. Therein, surfaces facing each other of the pair of prongs 14, 14 and an inner surface of the concave part 13 are continuous with each other to form one spherical concave surface. The snap cage 4 is made of a material having a bending elastic modulus at 120°C of 3,500 MPa or more. Further, the thickness t of pocket bottom part is 13% or more of the diameter of the ball.

Description

  The present invention relates to a crown type cage incorporated in a rolling bearing. The present invention also relates to a rolling bearing incorporating a crown-shaped cage.

In recent years, rolling bearings are often used under severe conditions such as high-speed rotation and high temperature. For example, in the case of a rolling bearing incorporated in a rotation support portion of a drive motor or an alternator for a hybrid vehicle, it is used at a high speed (a rotational speed of 10,000 min ⁻¹ or higher or a dmN value of 800,000 or higher) and a high temperature (100 ° C. or higher). There are many cases. The dmN value is a product of the bearing pitch circle diameter dm (unit: mm) and the rotational speed N (unit: min ⁻¹ ) of the rolling bearing.

  When the rolling bearing is used under high-speed rotation conditions, the cage in the rolling bearing rotates at a high speed together with a lubricant such as lubricating oil and grease existing between the outer peripheral surface of the inner ring and the inner peripheral surface of the outer ring. Since the centrifugal force is applied to the cage during high-speed rotation, the cage may be elastically deformed or plastically deformed by the action of the centrifugal force. When the cage is deformed (for example, radially outward deformation), the rolling bearing may be prevented from smoothly rotating, and the rolling bearing may be damaged. And under a high temperature condition, there exists a tendency for a deformation | transformation to be accelerated | stimulated.

  In order to suppress such deformation of the cage, it is effective to improve the rigidity of the cage. For example, Patent Document 1 discloses a crown-shaped cage that is not easily deformed as described above even when applied to a rolling bearing used under high-speed rotation and high-temperature conditions because of its high rigidity. That is, the crown-shaped cage includes an annular main portion and a plurality of pockets provided on one end surface in the axial direction of the main portion so as to accommodate the rolling elements in a rollable manner. Although it is comprised by the recessed part provided in the end surface, and a pair of one which pinches | interposes the recessed part from the circumferential direction both sides, the crown-shaped holder | retainer disclosed by patent document 1 has the radial direction length of the main part conventional The rigidity of the cage is improved by making it larger than that of a general crown-shaped cage.

JP 2000-291626 A Japanese Patent No. 3666536 JP 58-102823 A

However, the crown-shaped cage disclosed in Patent Document 1 has a larger length in the radial direction of the main portion, so that the portion other than the main portion, that is, the one portion also becomes larger. Therefore, compared to the conventional general crown-shaped cage, in addition to the increase in mass due to the increase in the main part, there is also an increase in mass due to the increase in the size of one part. There was a risk that it would become large and disadvantageous for high-speed rotation.
Therefore, an object of the present invention is to solve the above-described problems of the prior art and to provide a crown-shaped cage that is not easily deformed and is suitable for use under high-speed rotation and high-temperature conditions. Another object of the present invention is to provide a rolling bearing that is less likely to be damaged even when used under high-speed rotation and high-temperature conditions.

  In order to solve the above problems, an aspect of the present invention has the following configuration. That is, a crown-shaped cage according to an aspect of the present invention includes an annular main portion, and a plurality of pockets that are provided on one end surface in the axial direction of the main portion and accommodate a rolling element in a rollable manner. The pocket is a crown-shaped cage composed of a recess provided on the end face of the main portion and a pair of sandwiching the recess from both sides in the circumferential direction, and has a bending elastic modulus at 120 ° C. The axial distance between the bottom portion of the pocket and the other axial end surface of the main portion is 13% or more of the diameter of the rolling element. .

In this crown-shaped cage, the axial distance between the bottom of the pocket and the other axial end surface of the main part is preferably 17% or more of the diameter of the rolling element. Moreover, it is preferable to be comprised with the material whose bending elastic modulus in 120 degreeC is 4000 Mpa or more.
Furthermore, the material is a resin composition containing polyamide 46 and glass fiber, and the glass fiber content is preferably 25% by mass or more and less than 40% by mass of the resin composition.

  Further, the material is a resin composition containing polyamide 46 and carbon fiber, and the content of carbon fiber is preferably 10% by mass or more and less than 20% by mass of the resin composition. When the resin composition containing the polyamide 46 and the carbon fiber is used as a material, a crown-shaped cage may be manufactured by an injection molding method in which a melt of the resin composition is injected into a mold. It is preferable that no weld exists in the vicinity of the bottom of the pocket in the main portion. The adjacent portion intersects with the first imaginary line at an angle of 30 ° with the first imaginary line connecting the center of curvature of the spherical inner surface of the pocket and the bottom of the pocket as a second imaginary line. It is a part located inside the virtual conical surface formed by rotating a straight line.

Further, a rolling bearing according to another aspect of the present invention includes an inner ring, an outer ring, a plurality of rolling elements arranged to be freely rollable between the inner ring and the outer ring, and the inner ring and the outer ring between the inner ring and the outer ring. A retainer for holding a rolling element, wherein the retainer is the above-described crown-shaped retainer.
This rolling bearing can be used under the conditions of a temperature of 100 ° C. or higher and a dmN value of 800,000 or higher.

  The crown-shaped cage according to the present invention is made of a material having a bending elastic modulus at 120 ° C. of 3500 MPa or more, and the axial distance between the bottom of the pocket and the other axial end surface of the main portion is changed. Since it is 13% or more of the diameter of the moving body, the rigidity is high and deformation hardly occurs. Therefore, it is suitable for use under high speed rotation and high temperature conditions. In addition, the rolling bearing according to the present invention includes a cage that is highly rigid and is not easily deformed. Therefore, even if it is used under high-speed rotation and high-temperature conditions, damage is unlikely to occur.

It is a longitudinal cross-sectional view which shows the structure of the deep groove ball bearing which is one Embodiment of the rolling bearing which concerns on this invention. It is a perspective view of the crown-shaped cage incorporated in the deep groove ball bearing of FIG. It is the elements on larger scale which show the vicinity part of the bottom part of a pocket. It is a figure which shows the relationship between a gate position and a weld position. It is a figure which shows the relationship between a gate position and a weld position. It is a partial side view of a crown shaped cage explaining the amount of deformation. It is a graph which shows the relationship between the bending elastic modulus of the resin composition which comprises a crown-shaped cage, and the deformation amount of a crown-shaped cage. It is a graph which shows the relationship between pocket bottom part thickness and the deformation of a crown-shaped cage. It is a graph which shows the relationship between content of the glass fiber in a resin composition, and the bending elastic modulus of a resin composition. It is a graph which shows the relationship between content of the carbon fiber in a resin composition, and the bending elastic modulus of a resin composition. It is a graph which shows the relationship between content of the carbon fiber in a resin composition, and weld strength. It is a graph which shows the relationship between an intensity | strength ratio and the deviation | shift amount of a weld position.

DESCRIPTION OF EMBODIMENTS Embodiments of a crown-shaped cage and a rolling bearing according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a longitudinal sectional view showing the structure of a deep groove ball bearing which is an embodiment of a rolling bearing according to the present invention. FIG. 2 is a perspective view of a crown-shaped cage incorporated in the deep groove ball bearing of FIG.
The deep groove ball bearing shown in FIG. 1 includes an inner ring 1, an outer ring 2, a plurality of balls 3 that are rotatably arranged between a raceway surface 1a of the inner ring 1 and a raceway surface 2a of the outer ring 2, an inner ring 1 and an outer ring. 2, a crown-shaped cage 4 that holds a plurality of balls 3, and seals 5 and 5 interposed between the inner ring 1 and the outer ring 2. The seals 5 and 5 may not be provided. Further, a lubricant such as lubricating oil or grease is disposed in the bearing inner space surrounded by the inner ring 1, the outer ring 2, and the seals 5, 5, so that the raceway surfaces 1 a, 2 a of the inner ring 1 and the outer ring 2 and the balls 3 The rolling surface may be lubricated.

  Next, the crown-shaped cage 4 will be described with reference to FIG. The crown-shaped cage 4 includes an annular main portion 11 and a plurality of pockets 12 that are provided on one end surface in the axial direction of the main portion 11 and accommodate the balls 3 in a rollable manner. Each pocket 12 includes a recess 13 provided on the end surface of the main portion 11, and a pair of 14, 14 that are disposed opposite to each other at an edge of the recess 13 and sandwich the recess 13 from both sides in the circumferential direction. It is configured. And the mutually opposing surface of this pair of 14 and 14 and the inner surface of the recessed part 13 form one spherical recessed surface continuously.

Such a crown-shaped cage 4 rolls the ball 3 into each pocket 12 by pushing the ball 3 between the pair of 14, 14 while elastically expanding the distance between the two 14, 14. It can be held freely.
The crown-shaped cage 4 is made of a material having a flexural modulus at 120 ° C. of 3500 MPa or more. Further, the axial distance t (hereinafter referred to as “pocket bottom portion”) between the bottom portion of the pocket 12 (that is, the bottom portion of the concave portion 13 and the portion having the smallest axial length of the main portion 11) and the other end surface in the axial direction of the main portion 11. (Thickness t ”) may be 13% or more of the diameter of the ball 3 (see FIGS. 1 and 2).

Thus, since it is comprised with the highly elastic material and the pocket bottom part thickness t is large, the crown shape holder | retainer 4 has high rigidity and is hard to deform | transform. Therefore, even if the deep groove ball bearing incorporating the crown cage 4 is used under high-speed rotation and high-temperature conditions (for example, a temperature of 100 ° C. or higher and a dmN value of 800,000 or higher), deformation due to the centrifugal force of rotation (for example, Deformation in the radially outward direction) hardly occurs in the crown-shaped cage 4.
Therefore, the deep groove ball bearing of this embodiment has good rotational performance even when used under high-speed rotation and high-temperature conditions (for example, a temperature of 100 ° C. or higher and a dmN value of 800,000 or higher). Damage caused by deformation is less likely to occur. Such a deep groove ball bearing of this embodiment is suitable as a rolling bearing incorporated in a rotation support portion of a drive motor or alternator for a hybrid vehicle.

  The pocket bottom thickness t is more preferably 17% or more of the diameter of the ball 3. Then, since the rigidity of the crown-shaped cage 4 becomes higher, it becomes possible to use the crown-shaped cage 4 and the deep groove ball bearing of this embodiment under more severe rotation conditions and temperature conditions. Moreover, it is more preferable that the crown-shaped cage 4 is made of a material having a bending elastic modulus at 120 ° C. of 4000 MPa or more. Then, since the rigidity of the crown-shaped cage 4 becomes higher, it is possible to use the crown-shaped cage 4 and the deep groove ball bearing of the present embodiment under conditions of a temperature of 120 ° C. or more and a dmN value of 1 million or more. It becomes.

Further, increasing the pocket bottom thickness t, that is, the axial length of the main portion 11, has a larger effect of improving the rigidity of the crown-shaped cage 4 than increasing the radial length of the main portion. Therefore, the crown-shaped cage 4 of the present embodiment has higher rigidity than the crown-shaped cage disclosed in Patent Document 1 described above.
Furthermore, since the pocket bottom thickness t, that is, the axial length of the main portion 11 is increased, the size of the portions other than the main portion 11, that is, the 14 portions, is not changed. Therefore, although the mass increase by the main part 11 becoming large occurs compared with the conventional general crown-shaped cage, the other mass increase does not occur. Therefore, the crown-shaped cage 4 of the present embodiment is suitable for use at high speed rotation as compared with the crown-shaped cage disclosed in Patent Document 1 described above.
Here, the material which comprises the crown shape holder | retainer 4 is demonstrated. Although the material which comprises the crown shape holder | retainer 4 is not specifically limited, The resin composition containing resin and a fibrous filler (reinforcement material) is preferable.

  The type of the resin is not particularly limited, but an engineering plastic that can be injection-molded is preferable. Specifically, polyamide resin, polyphenylene sulfide (PPS), polyether ether ketone (PEEK), fluororesin (for example, polytetrafluoroethylene), polyether sulfone (PES), polyoxymethylene (POM), polybutylene terephthalate ( PBT), polyethylene terephthalate (PET), polyamideimide (PAI), polyetherimide (PEI), thermoplastic polyimide, polyethernitrile (PEN) and the like. These resin may be used individually by 1 type, and 2 or more types may be mixed and used for it.

  However, considering the cost of the crown-shaped cage 4 and the deep groove ball bearing, polyamide resin is preferable. Examples of the polyamide resin include aliphatic polyamide resins such as polyamide 11, polyamide 12, polyamide 46, polyamide 6, polyamide 66, polyamide 610, and polyamide 612, and aromatic polyamide resins such as modified polyamide 6T and polyamide 9T. . Of these polyamide resins, relatively inexpensive polyamide 66 and polyamide 46 are more preferable.

  Further, the type of fibrous filler is not particularly limited. For example, glass fiber, carbon fiber, metal fiber, aramid fiber, aromatic polyimide fiber, liquid crystal polyester fiber, silicon carbide fiber, alumina fiber, boron fiber , Wollastonite, silicon carbide whisker, silicon nitride whisker, alumina whisker, aluminum nitride whisker, potassium titanate whisker, aluminum borate whisker, zinc oxide whisker, magnesium oxide whisker, mullite whisker, calcium carbonate whisker, graphite whisker, magnesium oxy Examples include sulfate whiskers. These may be used alone or in combination of two or more.

  However, among these fibrous fillers, glass fibers and carbon fibers are preferable because of their good reinforcing properties. The addition amount of the fibrous filler may be appropriately selected in consideration of the mechanical properties (for example, bending elastic modulus, rigidity), moldability, assemblability, etc. of the crown-shaped cage, but is usually 10% by mass. It is 50 mass% or less. In addition, various additives such as a lubricant, a heat stabilizer, an antioxidant, and a plasticizer may be further added to the resin composition.

  As described above, the type of the resin composition constituting the crown-shaped cage 4 is not particularly limited. However, in consideration of cost, mechanical properties (for example, flexural modulus, rigidity), etc., glass fiber or carbon A polyamide resin reinforced with fibers is more preferable. For example, the resin composition containing polyamide 46 and glass fiber, and the glass fiber content is 25% by mass or more and less than 40% by mass, the polyamide 46 and carbon fiber are contained, and the carbon fiber content is 10% by mass. A resin composition that is less than 20% by mass is preferred.

If the glass fiber or carbon fiber content is less than the lower limit, a sufficient reinforcing effect cannot be obtained, so that the flexural modulus of the resin composition is lowered and the rigidity of the crown-shaped cage 4 is insufficient. There is a fear. On the other hand, when there is more content of glass fiber or carbon fiber than the said upper limit, there exists a possibility that the moldability of a resin composition may become inadequate.
The method for manufacturing such a crown-shaped cage 4 is not particularly limited, and a conventional resin molding method can be employed. Examples thereof include a melt molding method such as an injection molding method, a molding method by machining, and a sintering molding method.

  When the crown-shaped cage 4 is manufactured by the injection molding method, the width of the entrance of the pocket 12 (ie, the width of the entrance of the pocket 12 (ie, in order to prevent the one 14 from being damaged when released from the mold or installed in the rolling bearing)). The distance between the tips of the pair of 14, 14 sandwiching the recess 13 from both sides in the circumferential direction may be set to 0.91 to 0.98 times the diameter of the ball 3. In addition, when incorporating a crown cage into a rolling bearing, the crown cage is prevented from being damaged by incorporating moisture into the crown cage and heating it to a temperature higher than room temperature. can do.

Further, when the crown-shaped cage 4 is manufactured by the injection molding method, the weld position can be set at a position where a large stress does not act when the crown-shaped cage 4 is used regardless of a single point gate or a multipoint gate. preferable. For example, when a centrifugal force due to rotation is applied, it is preferable not to set a weld position at a position where the stress is most applied (generally, at the bottom of the pocket).
For example, the crown-shaped cage 4 is formed by an injection molding method in which a melt of a resin composition containing polyamide 46 and carbon fibers and having a carbon fiber content of 10% by mass or more and less than 20% by mass is injected into a mold. In the case of manufacturing, since the weld strength is remarkably reduced by the addition of the fibrous filler, it is preferable to mold the main portion 11 so that no weld exists in the vicinity of the bottom of the pocket 12.

Here, as shown in FIG. 3, the vicinity of the bottom of the pocket 12 is a first virtual line with the first virtual straight line X connecting the center of curvature C of the spherical inner surface of the pocket 12 and the bottom B of the pocket 12 as an axis. This is a portion (hatched portion in FIG. 3) located inside a virtual conical surface formed by rotating a second virtual straight line Y that intersects the straight line X at an angle θ of 30 ° and intersects at the center of curvature C. .
If no weld exists in the vicinity of the bottom, the weld position is not particularly limited. For example, the weld position may be set in a portion (column portion) between adjacent pockets 12.

  In the technique disclosed in Patent Document 2, a resin reservoir is provided corresponding to the weld position in the cavity of the mold so that the leading portion of the injected resin material exits from the cavity and flows into the resin reservoir. Is prevented. Further, in the technique disclosed in Patent Document 3, the position of the gate for injecting the resin material into the cavity of the mold is shifted from the circumferential central portion of the portion (column portion) between two adjacent pockets. This prevents the weld from being generated in the thinnest part of the pocket.

However, there is a case where weld is generated only by providing a resin reservoir as disclosed in Patent Document 2. Further, Patent Document 3 does not disclose how much the weld position is shifted from the thinnest part of the pocket.
As in the crown-shaped cage 4 of the present embodiment, if the weld is formed so that no weld exists in the vicinity of the bottom of the pocket 12 in the main part 11, the most stress is applied when centrifugal force is applied due to rotation. Since the weld does not exist at the position where the sag acts, the crown-shaped cage 4 is not easily damaged even if it is used under high-speed rotation and high-temperature conditions.

  The method of forming the crown-shaped cage 4 so that no weld is present in the vicinity of the bottom of the pocket 12 in the main portion 11 is not particularly limited. For example, the weld generation position may be shifted from the vicinity by adjusting the position of the gate for injecting the melt of the resin composition into the cavity of the mold. In addition, a resin reservoir is provided corresponding to the weld position in the mold cavity so that the top of the molten resin composition melt flows out of the cavity and flows into the resin reservoir. May be prevented.

4 and 5, the position of the gate for injecting the melt of the resin composition into the cavity of the mold is shifted from the circumferential center of the portion between the two adjacent pockets in the circumferential direction. It is a conceptual diagram illustrating an example in which the weld position is shifted so that no weld exists in the vicinity by setting the position closer to the pocket than the central portion in the circumferential direction.
FIG. 4 is an example in which a gate is provided in a mold so as to inject a melt of the resin composition from the outer diameter side of the crown-shaped cage 4, and (a) a partial perspective view and (b) an end view. In both cases, the relationship between the gate position and the weld position is described by displaying the gate position and the weld position on the crown-shaped cage 4.

FIG. 5 is an example in which a gate is provided in the mold so as to inject a melt of the resin composition from the inner diameter side of the crown-shaped cage 4, and as in FIG. 4, a partial perspective view of (a). In addition, the relationship between the gate position and the weld position is described by displaying the gate position and the weld position on the crown-shaped cage 4 together with the end views of FIGS.
In any of the examples shown in FIGS. 4 and 5, the above-described resin reservoir may be provided together. That is, a mold having a resin reservoir (not shown) at a position corresponding to the weld position shifted as described above is prepared, and the top portion of the injected resin composition melt comes out of the cavity and becomes a resin reservoir. The generation of welds may be suppressed by flowing in. The resin reservoir may be provided on the outer diameter side or the inner diameter side of the crown-shaped cage.

In addition, this embodiment shows an example of this invention and this invention is not limited to this embodiment. For example, in the present embodiment, the opposing surfaces of the pair of 14, 14 and the inner surface of the recess 13 continuously form one spherical concave surface, but are not limited to a spherical concave surface. The surface may be a cylindrical surface or other shape. In the case of a cylindrical surface, the central axis may be a cylindrical surface along the radial direction of the crown-shaped cage 4, or the central axis may be a cylindrical surface along the axial direction of the crown-shaped cage 4.
Moreover, in this embodiment, although the deep groove ball bearing was illustrated and demonstrated as a rolling bearing, the rolling bearing of this invention is applicable with respect to various other types of rolling bearings. For example, angular contact ball bearings and self-aligning ball bearings.

〔Example〕
Hereinafter, the present invention will be described more specifically with reference to examples. First, the following four resin compositions were prepared.
(1) A resin composition composed of polyamide 66 and glass fiber, and the glass fiber content is 25% by mass. Moreover, the bending elastic modulus in 120 degreeC of this resin composition is 3003 MPa.
(2) A resin composition comprising polyamide 46 and glass fiber, and the glass fiber content is 25% by mass. Moreover, the bending elastic modulus in 120 degreeC of this resin composition is 4000 MPa.

(3) A resin composition comprising polyamide 46 and carbon fiber, and the carbon fiber content is 15% by mass. Moreover, the bending elastic modulus in 120 degreeC of this resin composition is 5720 MPa.
(4) A resin composition comprising polyamide 46 and carbon fiber, and the carbon fiber content is 30% by mass. Moreover, the bending elastic modulus at 120 ° C. of this resin composition is 11175 MPa.
Using these four types of resin compositions as materials, a crown-shaped cage similar to the crown-shaped cage 4 shown in FIG. 2 was produced by an injection molding method. The pocket bottom thickness was 10.9%, 13.8%, 16.7%, 19.6%, 23.5%, or 28.3% of the diameter of the ball as the rolling element. .

  Using these crown-shaped cages, deep groove ball bearings having a nominal number of 6011 were assembled. This deep groove ball bearing has a bearing pitch circle diameter dm of 72.5 mm and a ball diameter of 10.319 mm. These deep groove ball bearings are rotated at a high temperature of 120 ° C. and a dmN value of 1 million for 10 hours under a high temperature condition, whether or not the rotating outer ring suddenly generates heat, and the amount of permanent deformation of the crown cage after rotation. Evaluated. As shown in FIG. 6, the amount of permanent deformation of the crown-shaped cage is the difference between the outer diameter (radius) of the crown-shaped cage before rotation and the outer diameter (radius) of the crown-shaped cage after rotation. It is. The evaluation results are shown in Tables 1 and 2.

As can be seen from Tables 1 and 2, the crown-shaped cage having insufficient rigidity has a large amount of permanent deformation, and sudden heat generation occurs in the outer ring.
Next, the relationship between the bending elastic modulus at 120 ° C. of the resin composition and the amount of permanent deformation of the crown cage is shown in the graph of FIG. The vertical axis on the left side of this graph shows the absolute value of the permanent deformation amount (unit is mm), and the vertical axis on the right side shows the ratio of the permanent deformation amount to the diameter of the ball (unit is%). Yes.
From the graph of FIG. 7, regardless of the pocket bottom thickness, if the bending elastic modulus at 120 ° C. of the resin composition is 3500 MPa or more, the amount of permanent deformation of the crown-shaped cage is suppressed to be small, and 4000 MPa or more. It can be seen that the amount of permanent deformation of the crown-shaped cage can be further reduced.

Next, the relationship between the ratio of the pocket bottom thickness to the ball diameter and the amount of permanent deformation of the crown cage is shown in the graph of FIG. As in the graph of FIG. 7, the left vertical axis of the graph of FIG. 8 indicates the absolute value of the permanent deformation amount (unit is mm), and the right vertical axis is the ratio of the permanent deformation amount to the diameter of the ball. (Unit is%).
From the graph of FIG. 8, when the bending elastic modulus at 120 ° C. of the resin composition is 4000 MPa or more, the permanent deformation amount of the crown-shaped cage when the ratio of the pocket bottom thickness to the ball diameter is 13% or more. It can be seen that the amount of permanent deformation of the crown-shaped cage can be further suppressed to be small when the amount is 17% or more. Furthermore, if the ratio of the pocket bottom thickness to the ball diameter exceeds 30%, the permanent deformation of the crown cage is suppressed to almost zero, so the ratio of the pocket bottom thickness to the ball diameter is 30%. The content is preferably set to 25% or less, and more preferably 25% or less. Thereby, the quantity of the resin composition used for manufacture of a crown-shaped cage can be controlled.

On the other hand, when the flexural modulus at 120 ° C. of the resin composition is 3003 MPa, the amount of permanent deformation of the crown-shaped cage can be suppressed to some extent by increasing the ratio of the pocket bottom thickness to the ball diameter. However, sudden heat generation of the outer ring occurred.
Next, the relationship between the glass fiber content in the resin composition comprising polyamide 46 and glass fibers and the flexural modulus at 120 ° C. of the resin composition is shown in the graph of FIG. From the graph of FIG. 9, it can be seen that in order to set the flexural modulus at 120 ° C. to 4000 MPa or more, when the resin is polyamide 46, the glass fiber content needs to be 25% by mass or more.

  Even when the glass fiber content is 40% by mass or more, the flexural modulus at 120 ° C. is hardly improved, and therefore the glass fiber content is preferably less than 40% by mass. When the glass fiber content is 40% by mass or more, not only the improvement in rigidity cannot be expected, but also when the crown cage is molded or incorporated into a rolling bearing, the crown cage is removed from the undercut portion. There is a risk of damage.

  Next, the relationship between the carbon fiber content in the resin composition comprising polyamide 46 and carbon fibers and the flexural modulus at 120 ° C. of the resin composition is shown in the graph of FIG. From the graph of FIG. 10, the greater the carbon fiber content, the greater the flexural modulus, the deformation of the crown-shaped cage during high-speed rotation can be suppressed, and the flexural modulus at 120 ° C. is 4000 MPa or more. When the resin is polyamide 46, it is understood that the content of carbon fiber needs to be 10% by mass or more.

  Next, the relationship between the carbon fiber content and the weld strength of the crown cage in the resin composition comprising polyamide 46 and carbon fiber is shown in the graph of FIG. The weld strength shown in the graph of FIG. 11 is the ratio of the strength of the weld portion to the strength of the non-weld portion. From the graph of FIG. 11, when the carbon fiber content in the resin composition is 20% by mass or more, the weld strength is remarkably reduced. Therefore, the carbon fiber content is preferably less than 20% by mass, and 15% by mass. It can be seen that it is more preferable to set the ratio to not more than%. Further, since the weld strength is reduced when the carbon fiber content is 10% by mass or more, it is understood that it is preferable to improve the weld strength of the crown cage regardless of the carbon fiber content. .

  Next, various types of crown-shaped cages with the weld position shifted from the bottom of the pocket were prepared, and the relationship between the amount of deviation of the weld position and the strength of the crown-shaped cage was investigated. A resin composition made of polyamide 46 and carbon fiber, the carbon fiber content of which is 15% by mass, is injection-molded, and a crown type cage for a deep groove ball bearing having a nominal number 6011 (inner diameter: 68 mm, outer diameter: 77 mm). , The number of pockets: 13).

Then, the tensile breaking strength (ring portion strength) of the main portion of the crown-shaped cage is measured and the tensile strength of the portion of the crown-shaped cage where the weld is not formed is measured. The ratio to the breaking strength (ring portion strength) was calculated. The relationship between the calculated intensity ratio and the amount of deviation of the weld position is shown in the graph of FIG. The displacement amount of the weld position shown on the horizontal axis of the graph of FIG. 12 is the angle θ formed by the first virtual line X and the second virtual line Y described above.
From the graph of FIG. 12, it can be seen that if the angle θ is 30 ° or more, a crown-shaped cage having a sufficiently excellent strength can be obtained.

DESCRIPTION OF SYMBOLS 1 Inner ring 2 Outer ring 3 Ball 4 Crowned cage 11 Main part 12 Pocket 13 Recessed 14 t Pocket bottom thickness B Pocket bottom C Center of curvature of spherical inner surface of pocket X First virtual straight line Y Second virtual straight line

Claims (8)

  A ring-shaped main portion, and a plurality of pockets provided on one end surface in the axial direction of the main portion so as to accommodate a rolling element in a rollable manner, wherein the pocket is provided in the end surface of the main portion. And a pair of ones sandwiching the concave portion from both sides in the circumferential direction, which is made of a material having a bending elastic modulus at 120 ° C. of 3500 MPa or more, A crown-shaped cage, wherein an axial distance between a bottom portion and the other axial end surface of the main portion is 13% or more of a diameter of the rolling element.   The crown-shaped cage according to claim 1, wherein an axial distance between a bottom portion of the pocket and the other axial end surface of the main portion is 17% or more of a diameter of the rolling element.   The crown-shaped cage according to claim 1 or 2, wherein the crown-shaped cage is made of a material having a flexural modulus at 120 ° C of 4000 MPa or more.   The material is a resin composition containing polyamide 46 and glass fiber, and the glass fiber content is 25% by mass or more and less than 40% by mass of the resin composition. The crown-shaped cage according to any one of the above.   The material is a resin composition containing polyamide 46 and carbon fiber, and the content of carbon fiber is 10% by mass or more and less than 20% by mass of the resin composition. The crown-shaped cage according to any one of the above.   It is manufactured by an injection molding method in which a melt of the resin composition is injected into a mold, and there is no weld in the vicinity of the bottom of the pocket of the main part, the vicinity is Rotating a second imaginary line that intersects the first imaginary line at an angle of 30 ° with the first imaginary line connecting the center of curvature of the spherical inner surface of the pocket and the bottom of the pocket as an axis. The crown-shaped cage according to claim 5, wherein the crown-shaped cage is a portion located inside an imaginary conical surface formed by.   An inner ring, an outer ring, a plurality of rolling elements that are rotatably arranged between the inner ring and the outer ring, and a cage that holds the rolling element between the inner ring and the outer ring, and A rolling bearing, wherein the cage is the crown-shaped cage according to any one of claims 1 to 6.   The rolling bearing according to claim 7, wherein the rolling bearing is used under conditions of a temperature of 100 ° C. or more and a dmN value of 800,000 or more.

Images