CN106662152A - Crown cage and angular contact ball bearing - Google Patents

Abstract

A cutout (34) is provided in the middle of the circumference of the end of the column portion (32), thereby forming a pair of claws (36) on both sides in the circumference. The relationship between the distance L between adjacent balls (3) and the ball pitch circle length πdm obtained by multiplying the ball pitch circle diameter dm by the circumference ratio π satisfies: 2.5×10 ^‑3 ≤ L/πdm ≤ 13×10 ^‑3 . The relationship between the minimum wall thickness M in the circumferential direction of the column portion (32), the circumferential width N of the claw portion (36), and the circumferential length πdm of the ball joint satisfies: -3.5×10 ^-3 ≤(M-2N)/πdm<0 .

Description

Crown cage and angular contact ball bearings

technical field

The invention relates to a crown type cage and an angular contact ball bearing.

Background technique

Ball screws that convert rotary motion into linear motion are used in linear feed mechanisms of machine tools such as CNC lathes, milling machines, machining centers, multi-function processing machines, and 5-axis processing machines, as well as in bed mounted spindle boxes and workpieces. As a bearing that rotatably supports the shaft end of the ball screw, an angular contact ball bearing is used (for example, refer to Patent Document 1). According to the type and size of the base on which the headstock and the workpiece are mounted on the machine tool used, the inner diameter of the bearing used for such angular contact ball bearings is left and right bearings.

The cutting load generated during machining and the inertial load when the headstock and base are moved with rapid acceleration act on the angular contact ball bearing as an axial load via the ball screw. The recent machine tool tends to increase the inertial load due to cutting load and rapid feed for the purpose of high-efficiency machining, and a large axial load acts on the angular contact ball bearing for supporting the ball screw.

Therefore, in order to increase the rolling fatigue life of such an angular contact ball bearing for supporting a ball screw, it is necessary to achieve both an increase in load capacity and high rigidity for maintaining machining accuracy.

In order to take care of these, it is sufficient to increase the size of the bearing or increase the number of rows combined. However, if the bearing size is increased, there will be more space at the end of the ball screw shaft. Also, if the number of rows combined is too large, the ball screw unit will become larger. As a result, since the required floor area and the dimension in the height direction of the machine tool increase, there are limits to the increase in the size of the bearing and the increase in the number of columns.

In addition, conventional angular contact ball bearings use obliquely cut cages (metal-cut or injection-molded resin cages) having a pair of rings on both sides in the axial direction (for example, refer to Patent Document 2 or 3). Such a cage having a ring structure on both sides is good in strength, but in the case of a structure in which seals are mounted on both end surfaces of the bearing, the space in the axial direction is insufficient. In addition, the volume of the internal space of the bearing is also small, and the amount of sealed grease is also limited.

prior art literature

patent documents

Patent Document 1: Japanese Patent Laid-Open No. 2000-104742

Patent Document 2: Japanese Patent Laid-Open No. 2005-61508

Patent Document 3: Japanese Patent Application Publication No. 3-49417

Contents of the invention

The problem that the present invention intends to solve

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a crown type cage and an angular contact ball bearing capable of achieving both increased load capacity and high rigidity in a limited space.

solutions to problems

The above objects of the present invention are achieved by the following configurations.

(1) A crown type cage, comprising:

a generally annular ring;

a plurality of post portions protruding axially at predetermined intervals from a front side or a back side of the ring portion;

a plurality of pocket portions formed between adjacent column portions capable of retaining balls respectively;

The crown type cage is manufactured by injection molding and used for ball bearings, wherein,

A cutout is provided in the middle of the circumference of the end of the column so as to form a pair of claws on both sides in the circumference,

The relationship between the distance L between the adjacent balls and the ball pitch diameter dm multiplied by the ball pitch circumference length πdm of the circumference ratio π satisfies:

2.5×10 ^-3 ≤ L/πdm ≤ 13×10 ^-3 ,

The relationship between the minimum wall thickness M in the circumferential direction of the column portion, the circumferential width N of the claw portion, and the circumferential length πdm of the ball joint satisfies:

-3.5×10 ⁻³ ≦(M−2N)/πdm<0.

(2) The crown type cage as described in (1),

The center position of the spherical surface of the pocket portion and the radial center positions of the outermost diameter portion and the innermost diameter portion of the ring portion are offset in the radial direction.

(3) The crown type cage as described in (1),

The center position of the spherical surface of the pocket portion and the radial center positions of the outermost diameter portion and the innermost diameter portion of the ring portion coincide in the radial direction.

(4) An angular contact ball bearing including the crown cage described in any one of (1) to (3).

The effect of the invention

According to the crown-shaped cage of the present invention, since 2.5×10 ^-3 ≤ L/πdm≤13×10 ^-3 is satisfied, the number of balls in each row of bearings (on the ball pitch circle) can be increased, and the load capacity of the bearing can be realized Increased and high rigidity. Also, if 2.5×10 ^-3 >L/πdm, the circumferential wall thickness of the column portion of the cage will be too thin, and holes will be formed during molding and cutting. In particular, when the synthetic resin which is the material of the crown-shaped cage contains a large amount of reinforcing material, the fluidity of the synthetic resin becomes poor during molding, and holes are more likely to be formed. Also, when L/πdm>13×10 ^-3 , the number of balls decreases, and the load carrying capacity and rigidity decrease.

In addition, since -3.5×10 ^-3 ≤(M-2N)/πdm<0 is satisfied, when the crown-shaped cage is manufactured by injection molding in the axial tension method, the end of the column part will not be damaged in the demoulding process The pair of claws can pull out the mold part forming the pocket in the axial direction. Assuming that -3.5×10 ^-3 >(M-2N)/πdm, cracks or breakages may occur in the claws during demolding, which may cause problems in the function of the cage. In addition, when (M-2N)/πdm≥0, there will be no compression interference between the pair of claws at the end of the column, but the distance between the adjacent pair of pockets will increase. The number of balls on the circle is reduced, so the load carrying capacity and rigidity may be lowered.

Description of drawings

FIG. 1 is a cross-sectional view of an angular contact ball bearing according to a first embodiment of the present invention.

Fig. 2 is a cross-sectional view of the angular contact ball bearings of Fig. 1 assembled side by side.

Fig. 3 is a side view of the cage.

Fig. 4 is a view of the cage viewed from one side in the axial direction.

Fig. 5 is a view of the cage viewed from the other side in the axial direction.

Fig. 6 is a VI-VI sectional view of Fig. 1 and Fig. 4 .

Fig. 7 is a sectional view taken along line VII-VII of Fig. 4 .

FIG. 8 is a diagram illustrating an arrangement state of a plurality of balls.

Fig. 9 is a sectional view of the cage shown together with the spherical mold.

10 is a cross-sectional view of an angular contact ball bearing according to a second embodiment of the present invention.

Fig. 11 is a side view of the cage.

Fig. 12 is a view of the cage viewed from one side in the axial direction.

Fig. 13 is a view of the cage viewed from the other side in the axial direction.

14 is a cross-sectional view of an angular contact ball bearing according to a third embodiment of the present invention.

Fig. 15 is a view of the cage viewed from one side in the axial direction.

Fig. 16 is a cross-sectional view taken along line XVI-XVI of Fig. 15 .

17 is a cross-sectional view of an angular contact ball bearing according to a fourth embodiment of the present invention.

Fig. 18 is a view of the cage viewed from one side in the axial direction.

19 is a cross-sectional view of an angular contact ball bearing according to a fifth embodiment of the present invention.

20 is a cross-sectional view of an angular contact ball bearing according to a modified example of the fifth embodiment of the present invention.

21 is a cross-sectional view of an angular contact ball bearing according to a sixth embodiment of the present invention.

Fig. 22 is a sectional view of a conventional deep groove ball bearing.

Fig. 23 is a view of a conventional cage viewed from the axial direction.

Fig. 24 is a side view of a conventional cage.

Explanation of reference signs

1: Angular contact ball bearing

3: Ball

4, 5: end face

10: outer ring

11: Raceway surface

12: Outer ring groove shoulder

13: Outer ring counterbore

14: Outer ring chamfering

15: Outer ring sealing groove

20: Inner ring

21: raceway surface

22: Inner ring groove shoulder

23: Inner ring counterbore

24: Inner ring chamfering

25: Inner ring sealing groove

30: Cage

31: ring department

31a: Radial inner side (one radial side, the other radial side)

31b: radially outer side (radially the other side, radially one side)

32: column part

33: Pocket

33a: arc

33b: 1st linear shape part

33c: 2nd Linear Shape Department

33g: 3rd linear shape part

34: Excision

35: Corner

36: claw

40: spherical mold

50: sealing parts

Oi: ball center (spherical center of the pocket)

detailed description

Next, the crown cage and the angular contact ball bearing according to the embodiment of the present invention will be described with reference to the drawings.

(first embodiment)

As shown in FIG. 1 , the angular contact ball bearing 1 of this embodiment includes: an outer ring 10 having a raceway surface 11 on the inner peripheral surface; an inner ring 20 having a raceway surface 21 on the outer peripheral surface; A plurality of balls 3 between the raceway surfaces 11 and 21 of the ring 20 ; and a crown-shaped cage 30 that rotatably holds the balls 3 and is a ball-guiding method.

The inner peripheral surface of the outer ring 10 has: the outer ring groove shoulder 12 protruding from the raceway surface 11 on the back side (load side; left side in FIG. 1 ); and concave from the raceway surface 11 on the front side Outer ring counterbore 13 on the side (opposite load side. Right side in Fig. 1).

The outer peripheral surface of the inner ring 20 has: an inner ring groove shoulder 22 protruding from the raceway surface 21 on the front side (load side; right side in FIG. 1 ); and recessed from the raceway surface 21 on the back side (opposite load side. Left side in Fig. 1) counterbore 23 of the inner ring.

Here, when the outer diameter of the inner ring counterbore 23 is D1 and the outer diameter of the inner ring groove shoulder 22 is D2, D1<D2. In addition, when the inner diameter of the outer ring counterbore 13 is D3 and the inner diameter of the outer ring groove shoulder 12 is D4, D3>D4. In this way, since the outer diameter D2 of the inner ring groove shoulder 22 is increased and the inner diameter D4 of the outer ring groove shoulder 12 is reduced, the contact angle α of the ball 3 can be set larger. More specifically, by setting the outer diameter D2 and the inner diameter D4 as described above, the contact angle α can be set to about 45°≦α≦65°. Considering the variation of the contact angle α when manufacturing the bearing, it can be about 50°≤α≤60°. In this way, the contact angle α can be increased.

In addition, when the radial height Hi of the inner ring groove shoulder 22 is divided by the diameter Dw of the ball 3 to obtain Ai (Ai=Hi/Dw), it is set to satisfy 0.35≦Ai≦0.50. When the radial height He of the outer ring groove shoulder 12 is divided by the diameter Dw of the ball 3 to be Ae (Ae=He/Dw), it is set to satisfy 0.35≤Ae≤0.50.

Assuming that in the case of 0.35>Ai or 0.35>Ae, since the radial heights Hi and He of the inner ring groove shoulder 22 or outer ring groove shoulder 12 are too small relative to the diameter Dw of the ball 3, the contact angle α is less than 45°, the load capacity of the axial load of the bearing is insufficient. In addition, in the case of 0.50<Ai or 0.50<Ae, since the raceway surfaces 11 and 21 of the outer ring 10 and the inner ring 20 are formed by overflowing the pitch circle diameter dm of the ball 3, the outer ring groove shoulder 12 and the inner ring Grinding of the groove shoulder 22 becomes difficult, which is not desirable.

In addition, a tapered outer ring chamfer 14 is provided on the back side end portion of the outer ring groove shoulder portion 12 so as to go radially outward as it goes to the back side. A tapered inner ring chamfer 24 is provided at the front side end portion of the inner ring groove shoulder 22 toward the front side in a tapered radial direction. The radial widths of these outer ring chamfers 14 and inner ring chamfers 24 are larger than half of the radial heights He and Hi of the outer ring groove shoulders 12 and inner ring groove shoulders 22 and are set to relatively large values.

Such angular contact ball bearings 1 can be used in parallel combination as shown in FIG. 2 . Since the angular contact ball bearing 1 of the present embodiment has the outer ring groove shoulder 12 and the inner ring groove shoulder 22 near the pitch circle diameter dm of the ball 3, it is assumed that the outer ring chamfer 14 and the inner ring chamfer 24 are not provided. , then the inner ring 20 of one angular contact ball bearing 1 interferes with the outer ring 10 of the other angular contact ball bearing 1, causing problems in bearing rotation. In addition, in the case of using oil lubrication, assuming that the outer ring chamfer 14 and the inner ring chamfer 24 are not provided, then the oil will not pass between the angular contact ball bearings 1, and the oil coating will deteriorate. A large amount of oil remains inside the bearing and the temperature rises. Thus, by providing the outer ring chamfer 14 and the inner ring chamfer 24 , it is possible to prevent the inner ring 20 and the outer ring 10 from interfering with each other, and to improve the oil coating property. In addition, both the outer ring chamfer 14 and the inner ring chamfer 24 do not necessarily need to be provided, but at least one of them should be provided.

Next, the configuration of the crown-shaped cage 30 will be described in detail with reference to FIGS. 3 to 7 . The crown-shaped cage 30 is a ball-guided plastic cage made of synthetic resin, and the base resin constituting the crown-shaped cage 30 is polyamide resin. In addition, the type of polyamide resin is not limited, and other synthetic resins such as polyacetal resin, polyphenylene sulfide, polyether ether ketone, and polyimide may be used instead of polyamide. In addition, glass fiber, carbon fiber, aramid fiber, etc. are added as reinforcing materials to the matrix resin. In addition, the crown-shaped cage 30 is manufactured by injection molding or cutting.

The crown-shaped cage 30 has: a substantially annular ring portion 31 (see FIG. 1 ) arranged coaxially with the inner ring 20 and the outer ring 10; pillar portions 32 ; a plurality of pocket portions 33 formed between adjacent pillar portions 32 .

Here, in the angular contact ball bearing 1 of this embodiment, since the radial heights He, Hi of the outer ring groove shoulder 12 and the inner ring groove shoulder 22 are increased in order to realize a high load capacity of the axial load, Therefore, the internal space of the bearing is reduced. Therefore, since the crown-shaped cage 30 arranged in the inner space of such a bearing has a single-sided ring structure, it is configured such that the ring portion 31 is arranged between the outer ring counterbore 13 and the inner ring groove shoulder 22 , and the ring portion 31 is arranged between the outer ring 10 and the inner ring. A column portion 32 is disposed between the raceway surfaces 11 and 21 of the ring 20 , and the ring portion 31 is connected to the radially outer end of the column portion 32 .

That is, as shown in FIG. 7, the center position of the spherical surface of the pocket portion 33 is radially inward (one side in the radial direction) compared with the radially intermediate position m of the outermost diameter portion m1 and the innermost diameter portion m2 of the ring portion 31. )stagger. Here, the center position of the spherical surface of the pocket portion 33 coincides with the center of the radius of curvature of the pocket portion 33 . In addition, the outermost diameter portion m1 of the ring portion 31 is a radially outer surface 31b, and the innermost diameter portion m2 is a radially inner surface 31a. In addition, in the illustrated example, the center position of the spherical surface of the pocket portion 33 is displaced radially inward from the innermost diameter portion m2 of the ring portion 31 .

As shown in FIG. 7 , the sides of the column portion 32 forming the pocket portion 33 viewed from the circumferential direction are: the radial inner side (one side in the radial direction) 31a of the ring portion 31 and the outer side in the radial direction (the other side in the radial direction). A part of the arc 33a connected with the side surface) 31b is cut away. The center of the arc 33a is denoted by P, and the radius is denoted by r.

More specifically, the side surface of the column portion 32 viewed in the circumferential direction includes a first linear portion 33b formed by cutting out the radially inner end portion (one end portion in the radial direction) of the arc 33a and extending it in the axial direction. . The first linear portion 33b is arranged on the rear side of the center P of the arc 33a. In addition, the first linear portion 33b overlaps with the center Oi of the ball 3 (the center of the spherical surface of the pocket portion 33 ) in the axial direction.

And, the side surface viewed from the circumferential direction of the column part 32 includes: the end part of the front side of the first linear shape part 33b of the arc 33a and the end part of the back side of the radial inner surface 31a of the ring part 31 are connected. The second linear shape portion 33c formed by partially cutting away. Therefore, the second linear shape portion 33c has a linear shape that goes radially outward as it goes toward the front side (the ring portion 31 side).

In addition, the side surface viewed from the circumferential direction of the column portion 32 includes a third linear portion 33g formed by cutting out the radially outer end (end portion on the other radial side) of the arc 33a and extending in the axial direction. The third linear portion 33g is formed on the same plane as the radially outer surface 31b of the ring portion 31, and is connected to the radially outer surface 31b without a step.

Thus, the side surface of the column part 32 viewed from the circumferential direction has a shape in which the third linear part 33g, the arc 33a, the first linear part 33b, and the second linear part 33c are connected.

In addition, as shown in FIG. 6 , the two circumferential side surfaces of the post 32 and the back side (post 32 side) of the ring 31 forming the pocket 33 are formed in a spherical shape similar to that of the ball 3 . Here, the end of the column portion 32 is provided with a cutout portion 34 in the middle in the circumferential direction, and is divided into two branches. Also, at the tip of the column portion 32 , a pair of claw portions 36 are formed on both sides in the circumferential direction of the cutout portion 34 . Here, the cutout portion 34 in this embodiment has a substantially V-shaped sharp cross-section, but is not limited to this shape, and may have, for example, a certain flat surface (for example, a flat surface of 0.1 mm or more) as a bottom surface. By providing the cutout portion 34 in this way, when the crown-shaped cage 30 is manufactured by injection molding in an axially stretched manner, even when the mold element forming the pocket portion 33 is forcibly pulled out, the pair of claws Since the portion 36 is elastically deformed toward the cutout portion 34 , damage to the corner portion 35 of the column portion 32 on the pocket portion 33 side can be prevented.

In addition, it is preferable that the proportion of the synthetic resin reinforcing material added to the material of the crown cage 30 is 5 to 30% by weight. Assuming that the proportion of reinforcing material in the synthetic resin component exceeds 30% by weight, the flexibility of the crown-shaped cage 30 decreases, so when the crown-shaped cage 30 is molded, the mold is forcibly pulled out from the pocket portion 33, and the ball is assembled when the bearing is assembled. 3 When pressing into the pocket portion 33, the corner portion 35 of the column portion 32 will be damaged. In addition, since the thermal expansion of the crown-shaped cage 30 depends on the linear expansion coefficient of the base material, that is, the resin material, when the proportion of the reinforcement material is less than 5% by weight, the thermal expansion of the crown-shaped cage 30 during bearing rotation is relatively small compared to the thermal expansion of the balls 3. The larger the expansion of the pitch circle diameter dm, the ball 3 and the pocket portion 33 of the crown cage 30 collide with each other, causing problems such as sintering. Therefore, the above-mentioned problems can be prevented by setting the ratio of the reinforcing material in the synthetic resin component in the range of 5 to 30% by weight.

In addition, as the synthetic resin material of the crown-shaped cage 30, resins such as polyamide, polyether ether ketone, polyphenylene sulfide, and polyimide can be used. As a reinforcing material for synthetic resin, glass fiber, carbon fiber, aramid fiber, etc. can be used.

In addition, in the angular contact ball bearing 1 of the present embodiment, the number of balls 3 (the number of balls Z) is set to be large in order to increase the axial load carrying capacity. More specifically, it demonstrates using FIG. 8. FIG. FIG. 8 shows two balls 3 arranged on a pitch circle of diameter dm. The diameter of these balls 3 is Dw, the center of these balls 3 is A, B, the intersection point of line segment AB and the surface of ball 3 is C, D, the middle point of line segment AB is E, the center of pitch circle is O. In addition, the distance between the centers A and B of adjacent balls 3 (distance of line segment AB), that is, the distance between ball centers is T, and the distance between adjacent balls 3 (distance of line segment CD), that is, the distance between balls is L, The angle formed by the line segment EO and the line segment BO (the angle formed by the line segment EO and the line segment AO) is θ. In this way, the distance between the line segment AO and the line segment BO is (dm/2), the distance T between the centers of the balls is (dm×sinθ), the distance L between the balls is (T-Dw), and the angle θ is (180°/Z) .

Furthermore, it is designed that the relationship 2.5×10 ^-3 ≤ L/πdm ≤ 13×10 ^-3 holds between the distance L between the balls and the ball pitch circumference length πdm obtained by multiplying the ball pitch diameter dm by the circumference ratio π. If L/πdm is less than 2.5×10 ^-3 , the circumferential wall thickness of the column portion 32 of the crown-shaped cage 30 becomes too thin, and holes are formed during molding or cutting. In particular, when the synthetic resin which is the material of the crown-shaped cage 30 contains a large amount of reinforcing material, the fluidity of the synthetic resin becomes poor during molding, and holes are more likely to be formed. In addition, when L/πdm exceeds 13×10 ^-3 , the number Z of balls decreases, and the axial load carrying capacity and rigidity of the bearing decrease.

In this way, the angular contact ball bearing 1 is designed to satisfy 2.5×10 ^-3 ≤ L/πdm ≤ 13×10 ^-3 , that is, the number of balls Z is relatively large, and the wall thickness of the cylindrical portion 32 of the crown cage 30 is relatively thicker than that of standard bearings. Can not thicken. Furthermore, as shown in FIG. 6 , as the minimum thickness M in the circumferential direction of the column portion 32 becomes thinner, the width N in the circumferential direction of the claw portion 36 also becomes smaller. Therefore, when the crown-shaped cage 30 is manufactured by injection molding of an axial stretching method, in order not to damage the column portion 32 in the demoulding process, the mold part forming the pocket portion 33 is pulled out in the axial direction, These minimum wall thickness M in the circumferential direction and width N in the circumferential direction need to be appropriately set. More specifically, it demonstrates using FIG. 9. FIG.

In the case of injection molding of the axial tension method, when the crown-shaped cage 30 is taken out from the inside of the mold, the mold relatively moves in the axial direction of the crown-shaped cage 30 . The spherical die 40 forming the inner shape of the pocket portion 33 elastically deforms the pair of claw portions 36 formed at the end of the post portion 32 and facing each other in the circumferential direction (direction of arrow A in the figure) toward the cutout portion 34 , while Pull out axially (in the direction of arrow B in the figure).

Here, the difference between the ball diameter dimension X of the spherical die 40 (the ball diameter dimension of the pocket portion 33) and the distance Y (the opening dimension of the mouth of the claw portion) from the claw portion 36 facing the adjacent column portion 32 ( X-Y), is the value called the forced extraction amount. In addition, the amount of forced extraction (X-Y) is set to an appropriate amount so that the ball does not fall out of the pocket portion 33 . When the forced extraction amount (X-Y) is too large, the claw portion 36 will exceed the limit of elastic deformation, and the claw portion 36 will be damaged or excessively plastically deformed during demoulding, hindering the function of the crown-shaped cage 30 . If the forced pulling amount (X-Y) is too small, the ball 3 will fall out of the pocket 33 . Therefore, the forced extraction amount (X-Y) is set in the range of Y/X=0.75 to 0.95 in view of these contradictory functions.

In the case of a crown-type cage used in a normal deep groove ball bearing, if the forced extraction amount is an appropriate value within the above range, the above-mentioned problems will not occur in the claw portion. However, in the crown-shaped cage 30 used in the present invention, the wall thickness of the column portion 32 is relatively thin due to internal design specifications of the bearing specific to the application. Therefore, when the mold is pulled out, the claws 36 are elastically deformed by the spherical mold 40 as described above, and the pair of claws 36 facing each other at the ends of the post 32 come into contact with each other so as to be crushed. When the amount of flattening exceeds a certain value, elastic deformation will be transferred to plastic deformation, resulting in problems such as damage or cracks of the claw portion 36 .

In the present invention, in anticipation of this problem, various design studies and verification results have found the following specifications that do not cause the above-mentioned problem. That is, the relationship between the minimum thickness M in the circumferential direction of the column portion 32, the width N in the circumferential direction of the claw portion 36, and the circumferential length πdm of the ball joint is set to satisfy -3.5×10 ^-3 ≤ (M-2N)/πdm<0 . Here, as shown in FIG. 6 , the minimum circumferential thickness M of the column portion 32 refers to the minimum value of the circumferential thickness of the column portion 32 other than the position where the claw portion 36 or the cutout portion 34 is formed.

Assuming that -3.5×10 ^-3 >(M-2N)/πdm, cracks or breakages that cause functional problems of the crown-shaped cage 30 are generated in the claw portions 36 during demolding. In addition, when (M-2N)/πdm≥0, there will be no compression interference between the pair of claws 36 facing the ends of the column 32, but the distance between the adjacent pockets 33 will increase, resulting in the arrangement of The number Z of balls on the ball pitch circle decreases, so the load carrying capacity and rigidity decrease. In addition, in deep groove ball bearings, etc., the number of balls is limited due to the limitation of the bearing assembly method, so the value of (M-2N) will not be smaller than 0.

In addition, the smaller the circumferential width N of the claw 36 is, the easier it is to satisfy -3.5×10 ^-3 ≤ (M-2N)/πdm<0. lead to poor molding. In addition, due to forcible pulling out at the time of demolding, cracks may occur at the tip of the claw portion 36, or the rigidity of the claw portion 36 may decrease, and the ball 3 may fall off. As a result of various verifications in the process of realizing the present invention, it has been found that the circumferential width N of the claw portion 36 is preferably 0.2 mm or more.

In particular, the configuration of the crown-shaped cage 30 according to the present embodiment exhibits this advantage particularly under the conditions that the resin material to which the above-mentioned reinforcing material is added tends to decrease the resin fluidity during injection molding and the molding die is difficult to forcibly pull out. Effect.

In addition, in the case of a conventional deep groove ball bearing 100 including balls 103, outer ring 110, inner ring 120, and cage 130 as shown in FIG. 22, the cage 130 is a crown as shown in FIGS. The cage has: a substantially circular ring portion 131; a plurality of pillar portions 132 projecting axially from the ring portion 131 at predetermined intervals; and a plurality of pocket portions 133 formed between adjacent pillar portions 132. .

In such a conventional type deep groove ball bearing 100, since its use is a relatively light load such as for a motor, and there are restrictions on the assembly of the deep groove ball bearing 100, it is different from the angular contact ball for ball screw support of this embodiment. Compared with bearing 1, the number of balls is about 1/2 to 1/3, which is less. Therefore, the pitch in the circumferential direction of the pockets 133 of the holder 130 is large, and the distance between the pair of corners 135 of the column 132 is greater than that between the pair of corners 35 of the column 32 of the present embodiment. Therefore, the concave portion 136 can be provided between the pair of corner portions 135 for the purpose of easily deforming the distal end portion of the column portion 132 when the mold is forcibly pulled out. In addition, the bottom surface 137 of the concave portion 136 may be a flat surface extending in the circumferential direction. Furthermore, a pin for demolding is provided on the bottom surface 137 of the recessed part 136, and the mold of the pocket part 133 can be demolded by pushing the pin out in the axial direction.

Thus, in the conventional type deep groove ball bearing 100, the cage 130 is less likely to be damaged when the die is forcibly pulled out, and thus the problem of the present invention has not been recognized.

(second embodiment)

The crown-shaped cage 30 according to the second embodiment, as shown in FIGS. 10 to 13 , is not provided with the first, second, and third straight-shaped portions 33b, 33c, and 33g as in the first embodiment (see FIG. 7 ). The side surface of the pillar portion 32 forming the pocket portion 33 as viewed from the circumferential direction has a circular shape with an arbitrary radius r.

In such a configuration, as in the first embodiment, it is set to satisfy 2.5×10 ^-3 ≤L/πdm≤13×10 ^-3 and -3.5×10 ^-3 ≤(M-2N)/πdm<0 , the same effect as that of the first embodiment can be obtained.

(third and fourth embodiments)

The spherical center position of the pocket portion 33 is not limited to the radially intermediate position m between the outermost diameter portion m1 and the innermost diameter portion m2 of the ring portion 31 as shown in the first and second embodiments shown in FIGS. 1 and 10 . A configuration that is shifted inward in the radial direction. That is, the structure may also be the same as the third embodiment shown in FIGS. 14 to 16 and the fourth embodiment shown in FIGS. 17 and 18 . The portion m1 is displaced radially outward from the radially intermediate position m of the innermost diameter portion m2.

That is, the structure may also be such that the ring portion 31 is arranged between the outer ring groove shoulder 12 and the inner ring counterbore 23, the column portion 32 is arranged between the raceway surfaces 11 and 21 of the outer ring 10 and the inner ring 20, and the ring portion 31 and the column The radially inner end of portion 32 is connected.

In addition, in the examples shown in FIGS. 14 to 18 , the position of the center of the spherical surface of the pocket portion 33 is displaced radially outward from the outermost diameter portion m1 (radially outer surface 31 b ) of the ring portion 31 . Even in this case, since the end of the column part 32 is provided with a cutout part 34 in the middle of the circumferential direction and is divided into two branches, when the cage 30 is manufactured by injection molding, it is possible to prevent the The corner portion 35 of the column portion 32 on the side of the pocket portion 33 is damaged due to the element being forcibly pulled out.

As shown in FIG. 16 , in the third embodiment, the side surface viewed from the circumferential direction of the column portion 32 forming the pocket portion 33 is: the radially outer side surface (one side surface in the radial direction) 31b of the ring portion 31 and the radial side surface A part of the arc 33a connecting the inner side surface (the other side surface in the radial direction) 31a is cut away. The center of the arc 33a is denoted by P, and the radius is denoted by r.

More specifically, the side surface of the column portion 32 viewed in the circumferential direction includes a first linear portion 33b formed by cutting out the radially outer end portion (one end portion in the radial direction) of the arc 33a and extending in the axial direction. . The 1st linear shape part 33b is arrange|positioned rather than the center P of a circle on the front side (opposite load side. The left side in FIG. 16). In addition, the first linear portion 33b overlaps with the center Oi of the ball 3 (the center of the spherical surface of the pocket portion 33 ) in the axial direction.

In addition, the side surface viewed from the circumferential direction of the column portion 32 includes an end portion of the arc 33a on the back side (load side; right side in FIG. 16 ) of the first linear portion 33b and a ring portion of the arc 33a. The portion connected to the front end of the radially outer surface 31b of 31 is cut away to form a second linear portion 33c. Therefore, the second linear shape portion 33c has a linear shape that goes radially inward as it goes toward the back side (the ring portion 31 side).

In addition, the side surface viewed from the circumferential direction of the column portion 32 includes a third linear portion 33g formed by cutting out the radial inner end portion (the other radial end portion) of the arc 33a and extending it in the axial direction. The third linear portion 33g is formed on the same plane as the radially inner surface 31a of the ring portion 31, and is connected to the radially inner surface 31a without a step.

Thus, the side surface of the column part 32 viewed from the circumferential direction has a shape in which the third linear part 33g, the arc 33a, the first linear part 33b, and the second linear part 33c are connected.

In addition, as shown in FIG. 17 , in the fourth embodiment, the side surface of the column portion 32 forming the pocket portion 33 as viewed from the circumferential direction has a circular shape with an arbitrary radius r.

Even in the case of such a configuration, as in the above-mentioned embodiment, by setting to satisfy 2.5×10 ^-3 ≤ L/πdm ≤ 13×10 ^-3 and -3.5×10 ^-3 ≤ (M-2N)/πdm <0, the same effect as that of the above-mentioned embodiment can be obtained.

(fifth embodiment)

As shown in FIG. 19 , the center position of the spherical surface of the pocket portion 33 and the radial middle position m of the outermost diameter portion m1 and the innermost diameter portion m2 of the ring portion 31 may coincide in the radial direction. In the illustrated example, the inner peripheral surface of the outer ring 10 has: an outer ring groove shoulder 12 protruding from the raceway surface 11 on the back side (load side; right side in FIG. 19 ); 11 is compared with the outer ring counterbore 13 that is recessed on the front side (opposite load side; left side in Fig. 19). On the outer peripheral surface of the inner ring 20 , inner ring groove shoulders 22 are protrudingly provided on the front side and the back side of the raceway surface 21 . Furthermore, a ring portion 31 is arranged between the outer ring groove shoulder 12 and the inner ring groove shoulder 22 , and a column portion 32 is arranged between the raceway surfaces 11 and 21 of the outer ring 10 and the inner ring 20 , and the distance between the ring portion 31 and the column portion 32 The radial center portion of the wall thickness connects. In addition, the side surface of the pillar part 32 which forms the pocket part 33 viewed from the circumferential direction is circular with arbitrary radius r.

Even in the case of such a configuration, as in the above-mentioned embodiment, by setting to satisfy 2.5×10 ^-3 ≤ L/πdm ≤ 13×10 ^-3 and -3.5×10 ^-3 ≤ (M-2N)/πdm <0, the same effect as that of the above-mentioned embodiment can be obtained.

In addition, the spherical center position (ball center Oi) of the pocket portion 33 is shifted from the axial center of the angular contact ball bearing 1 to the axial direction (front side). That is, the axial distance from the end face 4 of the angular contact ball bearing 1 on the rear side (right side in FIG. 19 ) where the ring portion 31 is disposed to the spherical center position of the pocket portion 33 is X, and from the front side ( FIG. 19 When the axial distance from the end surface 5 of the angular contact ball bearing 1 on the middle left side) to the center position of the spherical surface of the pocket portion 33 is Y, X>Y is set. Thereby, the axial space between the end face 4 of the angular contact ball bearing 1 on the back side and the surface of the ball 3 can be enlarged. Thereby, the axial dimension of the ring part 31 can be enlarged, and the ring strength of the ring part 31 can be improved.

In addition, if there is no problem with the strength of the ring portion 31, as shown in FIG. In this case, the relationship between the axial distances X and Y is X=Y.

(sixth embodiment)

As shown in FIG. 21 , the center position of the spherical surface of the pocket portion 33 and the radial middle position m of the outermost diameter portion m1 and the innermost diameter portion m2 of the ring portion 31 may coincide in the radial direction. In the illustrated example, the inner peripheral surface of the outer ring 10 has: an outer ring groove shoulder 12 protruding on the inner side (load side) in the axial direction compared with the raceway surface 11; Outer ring seal groove 15 recessed outward (anti-load side). The outer peripheral surface of the inner ring 20 has: an inner ring groove shoulder 22 protruding axially inwardly of the raceway surface 21 ; and an inner ring seal groove 25 recessed axially outwardly of the raceway surface 21 . Furthermore, a ring portion 31 is arranged between the outer ring groove shoulder 12 and the inner ring groove shoulder 22 , and a column portion 32 is arranged between the raceway surfaces 11 and 21 of the outer ring 10 and the inner ring 20 , and the distance between the ring portion 31 and the column portion 32 The radial center portion of the wall thickness connects. In addition, the side surface of the pillar part 32 which forms the pocket part 33 viewed from the circumferential direction is circular with arbitrary radius r. Furthermore, a seal member 50 is fixed to the outer ring seal groove 15 . The seal member 50 faces the inner ring seal groove 25 with a slight gap therebetween, and prevents foreign matter from entering the bearing. In addition, the sealing member 50 is not limited to a non-contact seal, but may be a contact seal.

As described above, by arranging the ring portion 31 on the axially inner side of the pocket portion 33 and arranging the seal member 50 on the axially outer side, the angular contact ball bearing 1 can be made compact. Such angular contact ball bearings 1 can be used in back-to-back combinations as shown in FIG. 21 .

Even in the case of such a configuration, as in the above-mentioned embodiment, by setting to satisfy 2.5×10 ^-3 ≤ L/πdm ≤ 13×10 ^-3 and -3.5×10 ^-3 ≤ (M-2N)/πdm <0, the same effects as those of the above-mentioned embodiment can be obtained.

Also in this embodiment, the spherical center position (ball center Oi) of the pocket portion 33 is shifted axially outward (front side) from the axial center of the angular contact ball bearing 1 as in the fifth embodiment. That is, the relationship of the axial distances X and Y is set as X>Y. Thereby, the axial space between the end face 4 of the angular contact ball bearing 1 on the back side (inward in the axial direction in FIG. 21 ) and the surface of the ball 3 can be enlarged. Thereby, the axial dimension of the ring part 31 can be enlarged, and the ring strength of the ring part 31 can be improved.

In addition, if there is no problem with the strength of the ring portion 31 , the configuration may be such that the spherical center position (ball center Oi) of the pocket portion 33 coincides with the axial center of the angular contact ball bearing 1 . In this case, the relationship between the axial distances X and Y is X=Y.

(Example 1 and 2)

Next, by changing (M-2N)/πdm as shown in Table 1, the crown-shaped cage 30 is produced by injection molding of the axial tension method, so that the damage state of the pair of claws 36 of the column part 32 experimenting. In addition, in Examples 1 and 2 and Comparative Example 1, parameters other than (M-2N)/πdm were the same as shown below.

Bearing inner diameter: Bearing outer diameter: Ball pitch circle diameter dm: Ball diameter Dw: 10.319mm, number of balls Z: 21, contact angle α: 60°, crown cage material: polyamide resin (mixed with 20wt.% glass fiber reinforced material), L/πdm: 3.6×10 ^-3

[Table 1]

(M-2N)/πdm Is there any damage to the claws? detailed status Example 1 -0.7×10 ^-3 ◎ no problem Example 2 -3.4×10 ^-3 ○ No functional problems (slight plastic deformation) comparative example -3.6×10 ^-3 x Unusable (cracks at the end of the claws)

As (M-2N)/πdm increases, a larger load is applied to the claw portion 36, and cracks are generated on the claw portion 36 especially in the comparative example where -3.5×10 ^-3 > (M-2N)/πdm . This is because compression interference occurs between the pair of claw portions 36 facing each other at the ends of the column portion 32 when the die is forcibly pulled out. From this result, it can be seen that the relationship between the minimum wall thickness M in the circumferential direction of the column portion 32, the width N in the circumferential direction of the claw portion 36, and the circumferential length πdm of the ball joint satisfies -3.5×10 ^-3 ≤ (M-2N)/ πdm<0.

Next, various examples in which a plurality of parameters of the angular contact ball bearing 1 are changed will be described.

(Example 3)

In this example, the inner diameter of the angular contact ball bearing 1 of the first embodiment is set to Φ30 mm, the outer diameter of the bearing is set to Φ62 mm, L/πdm=5.0×10 ^-3 , (M-2N)/ πdm = -1.4×10 ^-3 .

By setting each parameter in this way, it was confirmed that the same effects as those of the above-mentioned embodiment were obtained.

(Example 4)

In this example, the inner diameter of the angular contact ball bearing 1 of the second embodiment is set to Φ20 mm, the outer diameter of the bearing is set to Φ47 mm, L/πdm=11.4×10 ^-3 , (M-2N)/ πdm = -3.0×10 ^-3 .

By setting each parameter in this way,

Accordingly, it was confirmed that the same effects as those of the above-described embodiment were obtained.

(Example 5)

In this example, the inner diameter of the bearing in the angular contact ball bearings 1 of the third and fourth embodiments is set to Φ50 mm, the outer diameter of the bearing is set to Φ100 mm, L/πdm=3.5×10 ^-3 , (M- 2N)/πdm=-0.7×10 ^-3 .

By setting each parameter in this way, it was confirmed that the same effects as those of the above-mentioned embodiment were obtained.

(Example 6)

In this example, the inner diameter of the angular contact ball bearing 1 of the fifth embodiment is set to Φ20 mm, the outer diameter of the bearing is set to Φ47 mm, L/πdm=11.4×10 ^-3 , (M-2N)/ πdm = -3.0×10 ^-3 .

By setting each parameter in this way, it was confirmed that the same effects as those of the above-mentioned embodiment were obtained.

(Example 7)

In this example, the inner diameter of the angular contact ball bearing 1 of the sixth embodiment is set to Φ130 mm, the outer diameter of the bearing is set to Φ165 mm, L/πdm=2.7×10 ^-3 , (M-2N)/ πdm = -0.6×10 ^-3 .

By setting each parameter in this way, it was confirmed that the same effects as those of the above-mentioned embodiment were obtained.

In addition, this invention is not limited to the above-mentioned embodiment, A change, improvement, etc. can be added suitably.

This application is based on Japanese patent application 2014-136858 filed on July 2, 2014 and Japanese patent application 2015-117336 filed on June 10, 2015, the contents of which are incorporated herein by reference.

Claims (4)

1. a kind of crown type retainer, including：

Substantially circular ring portion；

Multiple post portions, from the face side or rear side of the ring portion at a predetermined interval to axially projecting；

Multiple pocket hole portions, form between the adjacent post portion, can respectively keep ball；

The crown type retainer is manufactured and for ball bearing by injection mo(u)lding, wherein,

The circumferentially intermediate of end in the post portion is provided with cut portion, so as to form a pair of claws in circumferential both sides,

The mutual ball pitch circumference degree π dm that pi is multiplied by apart from L and ball pitch diameter dm of the adjacent ball Relation, meet：

2.5×10^-3≤L/πdm≤13×10^-3,

The circumferencial direction minimum wall thickness (MINI W.) M in the post portion, circumferential width N of the claw and the ball pitch circumference degree π The relation of dm, meets：

-3.5×10^-3≤ (M-2N)/π dm ＜ 0.

2. crown type retainer as claimed in claim 1,

The sphere centre position of the pocket hole portion and the radial center position in the most outer diameter part of the ring portion and innermost diameter portion, in footpath To staggering.

3. crown type retainer as claimed in claim 1,

The sphere centre position of the pocket hole portion and the radial center position in the most outer diameter part of the ring portion and innermost diameter portion, It is radially consistent.

4. a kind of angular contact ball bearing,

Including claims 1 to 3 any one described in crown type retainer.