WO2015145794A1

WO2015145794A1 - Angular ball bearing

Info

Publication number: WO2015145794A1
Application number: PCT/JP2014/069087
Authority: WO
Inventors: 恭平松永; 美昭勝野
Original assignee: 日本精工株式会社
Priority date: 2014-03-28
Filing date: 2014-07-17
Publication date: 2015-10-01
Also published as: CN106460929A; JP6508196B2; CN106460929B; KR101960145B1; TWI576521B; KR20160128359A; TWI666390B; WO2015146811A1; TW201600747A; JPWO2015146811A1; JP2019074214A; TW201713866A

Abstract

A cage (30) that is a crown-type cage that has an approximately annular ring (31), a plurality of columns (32) that project in the axial direction from a front side or a rear side of the ring (31) at prescribed intervals, and a plurality of pockets (33) that are formed between adjacent columns (32). The position of the centers of the spherical surfaces of the pockets (33) is shifted to the radial direction inside with regard to the radial direction center of the ring (31). The radial direction cross-sectional shape of the pockets (33) is a circle that has an arbitrary radius (r) and that comprises a circular arc (33a) that connects a radial direction inside surface (31a) and a radial direction outside surface (31b) of the ring (31). At least one inside projecting part (38) that protrudes in the radial direction or an outside projecting part (39) that protrudes in the radial direction is formed in at least one of the radial direction inside surface (31a) and the radial direction outside surface (31b) of the ring (31).

Description

Angular contact ball bearings

The present invention relates to an angular contact ball bearing.

Ball screws that convert rotary motion into linear motion are used for machine tools such as NC lathes, milling machines, machining centers, multi-axis machines, and 5-axis machines, and linear feed mechanisms for beds and spindle heads. Has been. An angular ball bearing is employed as a bearing that rotatably supports the shaft end of the ball screw (for example, see Patent Document 1). These bearings have a bearing inner diameter of about 10 mm to about 100 mm depending on the size of the headstock of the machine tool used or the bed on which the workpiece is mounted.

The cutting load generated during machining and the inertia load when the headstock and bed are moved at a rapid acceleration are applied as an axial load to the angular ball bearing via the ball screw. In recent machine tools, cutting loads and inertia loads due to rapid feed are large for the purpose of high-efficiency machining, and angular ball bearings tend to be loaded with large axial loads.

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

Japanese Unexamined Patent Publication No. 2000-104742

In order to achieve both of these, the bearing size can be increased or the number of combinations can be increased. However, if the bearing size is increased, the space at the ball screw shaft end increases, and the number of combinations is increased. If the number is increased excessively, the ball screw unit portion becomes wide. As a result, the required floor area of the machine tool increases and the height dimension increases, so there is a limit to the increase in the size of the bearings and the number of rows.

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

The above object of the present invention can be achieved by the following constitution.
(1) an outer ring having a raceway surface on the inner peripheral surface;
An inner ring having a raceway surface on the outer peripheral surface;
A plurality of balls disposed between the raceways of the outer ring and the inner ring;
Holding the ball so as to roll freely, a cage that is a ball guide system,
An angular contact ball bearing comprising:
On the outer peripheral surface of the inner ring, an inner ring counterbore is recessed on the back side, and an inner ring groove shoulder is protruded on the front side,
On the inner peripheral surface of the outer ring, an outer ring counter bore is recessed on the front side, and an outer ring groove shoulder is protruded on the back side,
The contact angle α of the balls is 45 ° ≦ α ≦ 65 °,
When Ai is obtained by dividing the radial height of the inner ring groove shoulder by the diameter of the ball, 0.35 ≦ Ai ≦ 0.50,
When Ae is obtained by dividing the radial height of the outer ring groove shoulder by the diameter of the ball, 0.35 ≦ Ae ≦ 0.50,
The cage is formed between a substantially annular ring portion, a plurality of column portions protruding in the axial direction at a predetermined interval from the front side or the back side of the ring portion, and a plurality of adjacent column portions. And a pocket-shaped cage having
The spherical center position of the pocket portion is shifted to one radial side with respect to the radial center of the ring portion,
The radial cross-sectional shape of the pocket portion is a circle with an arbitrary radius composed of an arc connecting the one radial side surface and the other radial side surface of the ring portion,
The angular ball bearing according to claim 1, wherein at least one convex portion projecting in the radial direction is formed on at least one of the one radial side surface and the other radial side surface of the ring portion.
(2) The angular ball bearing according to (1), wherein the circular arc is a first straight shape portion that is notched at one end portion in the radial direction and extends in the axial direction.
(3) The circular arc is characterized in that a portion connecting the first straight shape portion and the one side surface in the radial direction of the ring portion is cut out to be a second straight shape portion ( Angular contact ball bearings as described in 2).
(4) The relationship between the distance L between the adjacent balls and the ball pitch circumference length πdm obtained by multiplying the ball pitch circle diameter dm by the circumference ratio π is 2.5 × 10 ⁻³ ≦ L / πdm The angular contact ball bearing according to any one of (1) to (3), wherein ≦ 13 × 10 ⁻³ is satisfied.

According to the angular ball bearing of the present invention, the contact angle α of the ball satisfies 45 ° ≦ α ≦ 65 °. Therefore, by increasing the contact angle, the load capacity of the axial load of the bearing increases, and a larger preload. Can be used with load. As a result, the rigidity of the bearing and thus the ball screw system can be improved.
In addition, when Ai is obtained by dividing the radial height of the inner ring groove shoulder by the ball diameter, 0.35 ≦ Ai ≦ 0.50, and the radial height of the outer ring groove shoulder is divided by the ball diameter. When Ae is 0.35 ≦ Ae ≦ 0.50, it is possible to easily grind the inner and outer ring groove shoulders while preventing the bearing load capacity from being insufficient. Is possible.
In addition, since at least one convex portion projecting in the radial direction is formed on at least one of the one radial side surface and the other radial side surface of the ring portion, the pocket portion is formed when the cage is manufactured by injection molding. It is possible to forcibly remove the mold parts that form the mold.

It is sectional drawing of the angular ball bearing which concerns on embodiment of this invention. It is sectional drawing which combined the angular ball bearing of FIG. 1 in parallel. It is a side view of a holder | retainer. It is the figure which looked at the holder | retainer from the axial direction one side. It is the figure which looked at the holder | retainer from the other side in the axial direction. FIG. 6 is a sectional view taken along the line VI-VI in FIG. 4. It is sectional drawing of a holder | retainer. It is sectional drawing of the conventional deep groove ball bearing. It is the figure which looked at the holder | retainer when a radial load is loaded from the axial direction one side. It is sectional drawing of an angular contact ball bearing when a radial load is applied to a cage. It is a figure for demonstrating the arrangement | positioning state of a some ball. It is sectional drawing of the conventional angular contact ball bearing. XIII-XIII cross-sectional view of the cage and ball of FIG. 12 is indicated by solid lines, and in the cage and ball of FIG. 12, the pocket portion of the cage is moved in the axial direction as indicated by broken lines. The -XIII cross section is indicated by a broken line. It is the figure which looked at the holder | retainer of FIG. 12 from the XIV direction. It is a figure which shows the holder | retainer of this invention. It is the figure which looked at the conventional cage | basket from the axial direction. It is a side view of the conventional cage | basket. It is sectional drawing of the angular ball bearing which concerns on a modification. It is sectional drawing of the angular ball bearing which concerns on a modification. It is sectional drawing of the angular ball bearing which concerns on a modification. It is sectional drawing of the angular ball bearing which concerns on a modification. It is the figure which looked at the holder | retainer of FIG. 21 from the axial direction one side. It is sectional drawing of the holder | retainer of FIG.

Hereinafter, an angular ball bearing according to an embodiment of the present invention will be described with reference to the drawings.

As shown in FIG. 1, the angular ball bearing 1 of the present embodiment includes an outer ring 10 having a raceway surface 11 on an inner peripheral surface, an inner ring 20 having a raceway surface 21 on an outer peripheral surface, and raceway surfaces of the outer ring 10 and the inner ring 20. 11 and 21, a plurality of balls 3, and a retainer 30 that holds the balls 3 in a freely rolling manner and is a ball guide system.

The outer peripheral surface of the outer ring 10 is protruded on the back side (load side; left side in FIG. 1) of the raceway surface 11 and the front side of the raceway surface 11 (on the anti-load side). 1 on the right side of the outer ring counter bore 13.

The outer peripheral surface of the inner ring 20 is an inner ring groove shoulder 22 projecting on the front side (load side; right side in FIG. 1) from the raceway surface 21, and the back side (anti-load side, FIG. 1). And an inner ring counter bore 23 recessed in the middle left side.).

Here, if the outer diameter of the inner ring counterbore 23 is D1 and the outer diameter of the inner ring groove shoulder 22 is D2, then D1 <D2 and the inner diameter of the outer ring counterbore 13 is D3, and the outer ring groove shoulder 12 If the inner diameter of D4 is D4, then D3> D4. Thus, 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 decreased, the contact angle α of the ball 3 can be set large. 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 °, and the variation in the contact angle α during the manufacture of the bearing can be reduced. Even if it considers, it can be set as about 50 degrees <= alpha <= 60 degrees, and contact angle alpha can be enlarged.

Further, when Ai is obtained by dividing the radial height Hi of the inner ring groove shoulder portion 22 by the diameter Dw of the ball 3 (Ai = Hi / Dw), it is set to satisfy 0.35 ≦ Ai ≦ 0.50. If the value obtained by dividing the radial height He of the outer ring groove shoulder 12 by the diameter Dw of the ball 3 is Ae (Ae = He / Dw), it is set to satisfy 0.35 ≦ Ae ≦ 0.50. .

If 0.35> Ai or 0.35> Ae, the radial heights Hi and He of the inner ring groove shoulder 22 or the outer ring groove shoulder 12 are too small with respect to the diameter Dw of the ball 3. Therefore, the contact angle α is less than 45 °, and the load capacity of the bearing in the axial direction is insufficient. Further, when 0.50 <Ai or 0.50 <Ae, the raceway surfaces 11 and 21 of the outer ring 10 and the inner ring 20 are formed so as to protrude from the pitch circle diameter dm of the ball 3, Grinding of the outer ring groove shoulder 12 and the inner ring groove shoulder 22 becomes difficult, which is not desirable.

Further, a taper-shaped outer ring chamfer 14 is provided at the rear side end portion of the outer ring groove shoulder portion 12 so as to go radially outward toward the rear side. A taper-shaped inner ring chamfer 24 that is directed radially inward toward the front side is provided. The radial widths of the outer ring chamfer 14 and the inner ring chamfer 24 are set to a relatively large value that is larger than half of the radial heights He and Hi of the outer ring groove shoulder 12 and the inner ring groove shoulder 22.

Such an angular ball bearing 1 can be used in parallel as shown in FIG. Since the angular ball bearing 1 of the present embodiment is provided with the outer ring groove shoulder 12 and the inner ring groove shoulder 22 up to the vicinity of the pitch circle diameter dm of the ball 3, the outer ring chamfer 14 and the inner ring chamfer 24 are not provided. The inner ring 20 of one angular ball bearing 1 and the outer ring 10 of the other angular ball bearing 1 interfere with each other, causing a problem during rotation of the bearing. In addition, when used in oil lubrication, if the outer ring chamfer 14 and the inner ring chamfer 24 are not provided, the oil does not pass between the angular ball bearings 1, and the oil is poorly lubricated. Leads to a temperature rise due to a large amount of remaining. Thus, by providing the outer ring chamfer 14 and the inner ring chamfer 24, it is possible to prevent interference between the inner ring 20 and the outer ring 10 and to improve oil repellency. Both the outer ring chamfer 14 and the inner ring chamfer 24 do not necessarily need to be provided, and at least one may be provided.

Next, the configuration of the cage 30 will be described in detail with reference to FIGS. The cage 30 is a ball guide type plastic cage made of synthetic resin, and the base resin constituting the cage 30 is a polyamide resin. In addition, the kind of polyamide resin is not restrict | limited, Other synthetic resins, such as a polyacetal resin, polyetheretherketone, a polyimide, may be used besides polyamide. Furthermore, glass fiber, carbon fiber, aramid fiber, or the like is added to the base resin as a reinforcing material. The cage 30 is manufactured by injection molding or cutting.

The retainer 30 includes a substantially annular ring portion 31 (see FIG. 1) disposed coaxially with the inner ring 20 and the outer ring 10, and a plurality of protrusions protruding in the axial direction at a predetermined interval from the back side of the ring portion 31. It is a crown type retainer having a column portion 32 and a plurality of pocket portions 33 formed between adjacent column portions 32.

Here, in the angular ball bearing 1 of the present embodiment, the radial heights He and Hi of the outer ring groove shoulder portion 12 and the inner ring groove shoulder portion 22 are increased in order to realize a high load capability of the axial load. The bearing internal space is reduced. Therefore, when the cage 30 arranged in such a bearing internal space is a crown type cage (one-side ring structure), the ring portion 31 is arranged between the outer ring counter bore 13 and the inner ring groove shoulder portion 22, and the outer ring 10 and the raceway surfaces 11 and 21 of the inner ring 20, the column portion 32 is arranged, and the ring portion 31 is connected to the radially outer end of the column portion 32. That is, the spherical center position of the pocket portion 33 is shifted from the radial center of the ring portion 31 radially inward (one radial direction side).

As shown in FIG. 7, the radial cross-sectional shape of the pocket portion 33 is from an arc 33a connecting the radial inner side surface (one radial side surface) 31a and the radial outer side surface (radial other side surface) 31b of the ring portion 31. A circle with an arbitrary radius r. The center of the circle is indicated by P. The arc 33a is a first straight-shaped portion 33b extending in the axial direction by cutting out the radially inner portion (one radial portion). The first straight shape portion 33b is disposed on the back side of the center P of the circle. The arc 33a has a second straight shape in which a portion connecting the front end of the first straight shape portion 33b and the back end of the radial inner side surface 31a of the ring portion 31 is notched. Part 33c. Therefore, the 2nd straight shape part 33c is made into the linear shape which goes to a radial direction outer side as it goes to the front side (ring part 31 side). Further, the first straight shape portion 33b is formed so that the center Oi of the ball 3 (spherical center of the pocket portion 33) overlaps the first straight shape portion 33b in the axial direction.

Further, as shown in FIG. 6, both side surfaces in the circumferential direction of the column portion 32 and side surfaces on the back side (column portion 32 side) of the ring portion 31 forming the pocket portion 33 are spherical shapes similar to the balls 3. Formed. Here, the tip of the column part 32 is provided with a notch 34 having a substantially V-shaped cross section in the middle in the circumferential direction, and is divided into two. Thereby, when manufacturing the holder | retainer 30 by injection molding, the breakage | damage of the corner | angular part 35 by the side of the pocket part 33 of the pillar part 32 by the forced removal of the metal mold part which forms the pocket part 33 can be prevented.

Further, the ratio of the reinforcing material added to the synthetic resin of the cage 30 material is preferably 5 to 30 weight percent. If the proportion of the reinforcing material in the synthetic resin component exceeds 30% by weight, the flexibility of the cage 30 is reduced. Therefore, when the mold is forcibly removed from the pocket portion 33 when the cage 30 is molded, When the ball 3 is press-fitted into the pocket portion 33 during assembly, the corner portion 35 of the column portion 32 is damaged. Further, since the thermal expansion of the cage 30 depends on the linear expansion coefficient of the resin material that is the base material, if the proportion of the reinforcing material is less than 5 weight percent, the thermal expansion of the cage 30 during the rotation of the bearing causes the ball 3 to rotate. As the pitch circle diameter dm expands, the ball 3 and the pocket portion 33 of the cage 30 stick against each other, causing problems such as seizure. Therefore, the above-mentioned problem 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 a synthetic resin material for the cage 30, a resin such as polyamide, polyetheretherketone, polyphenylene sulfide, or polyimide is applied, and as a reinforcing material, glass fiber, carbon fiber, aramid fiber, or the like is applied.

Here, in the deep groove ball bearing 100 having a conventional crown-shaped cage as shown in FIG. 8, the cage 130 and the inner ring 120 or the outer ring 110 do not overlap in the radial direction. Therefore, even if the cage 130 exceeds the design value due to the inertia at the time of starting and stopping the rotation of the deep groove ball bearing 100, even if the cage 130 moves in the axial direction relative to the inner ring 120 or the outer ring 110, There is no interference with the inner ring 120 or the outer ring 110.

However, when the cage 30 and the inner ring 20 or the outer ring 10 overlap in the radial direction as in the angular ball bearing 1 of the present embodiment, the cage 30 exceeds the design value, and the inner ring 20 or the outer ring 10 Thus, the cage 30 and the inner ring 20 or the outer ring 10 may interfere with each other when moving relatively in the axial direction. If the radial cross-sectional shape of the pocket portion 33 of the cage 30 is a shape that does not have the second straight shape portion 33c, the axial distance ΔS1 between the cage 30 and the inner ring 20 (see FIG. 1). ) Becomes narrow, and the possibility that the cage 30 and the inner ring 20 interfere with each other increases. If the retainer 30 and the inner ring 20 interfere with each other, the torque fluctuates when the retainer 30 and the inner ring 20 interfere with each other, and accurate positioning as a ball screw system cannot be performed. Wear and lead to breakage of the cage 30. Further, the wear powder generated when the cage 30 is worn becomes foreign matter, and the bearing lubrication state is deteriorated. As a result, the life of the bearing is shortened.

Therefore, as in the angular ball bearing 1 of the present embodiment, the axial distance ΔS1 between the cage 30 and the inner ring 20 can be increased by forming the second straight shape portion 33c in the pocket portion 33. It is possible to reduce the possibility that the cage 30 and the inner ring 20 interfere with each other.

Further, in order to maintain a large contact angle α as in the angular ball bearing 1 of the present embodiment, the radial heights He and Hi of the outer ring groove shoulder 12 and the inner ring groove shoulder 22 are set to the pitch circle of the ball 3, respectively. When the diameter is increased to near dm, the radial space between the outer ring 10 and the inner ring 20 is narrowed, and the radial thickness of the ring portion 31 of the cage 30 located in the space between the outer ring 10 and the inner ring 20 is larger than that of the standard bearing. Cannot be thick. In particular, in the case of a crown-shaped cage, since the ring portion 31 exists only on one side in the axial direction of the cage 30, there is a concern that the strength of the ring portion 31 may be reduced due to insufficient thickness.

Furthermore, the material of the cage 30 is a synthetic resin such as polyamide resin, polyacetal resin, polyetheretherketone, polyimide, and the reinforcing fiber content in the base resin is 30 weight percent or less. For this reason, the strength of the ring portion 31 of the cage 30 tends to be low, and when a radial impact load or vibration load is applied, the cage 30 bends in the radial direction. In FIGS. 9 and 10, an example of the shape when the radial load F is applied to the cage 30 and the cage 30 is bent in the radial direction is schematically represented by a broken line. When the cage 30 bends in the radial direction, the radial position of the cage 30 approaches the inner ring 20 side or the outer ring 10 side. As a result, the axial distance ΔS1 between the cage 30 and the inner ring 20 is reduced, and the possibility that the cage 30 and the inner ring 20 interfere with each other increases. If the radial cross-sectional shape of the pocket portion 33 of the cage 30 is a shape that does not have the second straight shape portion 33c, the axial distance ΔS1 between the cage 30 and the inner ring 20 is narrowed and retained. The possibility that the container 30 and the inner ring 20 interfere with each other increases. Therefore, as in the angular ball bearing 1 of the present embodiment, the axial distance ΔS1 between the cage 30 and the inner ring 20 can be increased by forming the second straight shape portion 33c in the pocket portion 33. It is possible to reduce the possibility that the cage 30 and the inner ring 20 interfere with each other.

In addition, since the radial thickness of the ring portion 31 of the cage 30 located in the space between the outer ring 10 and the inner ring 20 cannot be increased with respect to the standard bearing, the bending rigidity of the ring portion 31 may not be sufficient. In this case, as indicated by an arrow A in FIG. 6, the distal end of the column part 32 expands radially outward by the centrifugal force acting on the column part 32 of the cage 30 when the bearing is used, and the corner part 35 extends in the circumferential direction. It becomes easy to spread. Therefore, the axial movement amount ΔA of the cage 30 is increased. When the axial movement amount ΔA of the cage 30 increases in this way, the axial distance ΔS1 between the cage 30 and the inner ring 20 becomes narrow, and there is a high possibility that the cage 30 and the inner ring 20 interfere with each other. Become. If the radial cross-sectional shape of the pocket portion 33 of the cage 30 is a shape that does not have the second straight shape portion 33c, the axial distance ΔS1 between the cage 30 and the inner ring 20 is narrowed and retained. The possibility that the container 30 and the inner ring 20 interfere with each other increases. Therefore, as in the angular ball bearing 1 of the present embodiment, the axial distance ΔS1 between the cage 30 and the inner ring 20 can be increased by forming the second straight shape portion 33c in the pocket portion 33. It is possible to reduce the possibility that the cage 30 and the inner ring 20 interfere with each other.

Further, the angular ball bearing 1 of the present embodiment is set so that the number of balls 3 (the number of balls Z) is increased in order to increase the axial load capacity. This will be described more specifically with reference to FIG. FIG. 11 shows two balls 3 arranged on a pitch circle having a diameter dm, the diameter of these balls 3 is Dw, the centers of these balls 3 are A and B, and a line segment AB. The intersection of the ball 3 and the surface of the ball 3 is C, D, the midpoint of the line segment AB is E, and the center of the pitch circle is O. In addition, the distance between the centers of the balls 3 that is the distance between the centers A and B of the adjacent balls 3 (distance of the line segment AB) is T, and the distance between the balls that is the distance of the adjacent balls 3 (the distance of the line segment CD). Is L, and the angle between line segment EO and line segment BO (angle between line segment EO and line segment AO) is θ. Then, the distance between the line segment AO and the line segment BO is (dm / 2), the ball center distance T is (dm × sin θ), the ball distance L is (T−Dw), and the angle θ is (180 ° / Z).

Between the ball distance L and the ball pitch pitch diameter dm multiplied by the ball pitch circle diameter dm, the pitch 3 pitch circumference length πdm is 2.5 × 10 ⁻³ ≦ L / πdm ≦ 13 × 10 ^The design is such that the relationship of ⁻³ is established. If L / πdm is smaller than 2.5 × 10 ⁻³ , the circumferential thickness of the pillar portion 32 of the cage 30 becomes too thin, and a hole is opened during molding or cutting. In particular, when a large amount of reinforcing material is contained, the fluidity of the synthetic resin, which is the material of the cage 30, is deteriorated at the time of molding, and holes are easily opened. On the other hand, if L / πdm is larger than 13 × 10 ⁻³ , the number of balls Z is reduced, and the axial load carrying capacity and rigidity of the bearing are lowered.

As described above, the angular ball bearing 1 is designed so as to satisfy 2.5 × 10 ⁻³ ≦ L / πdm ≦ 13 × 10 ⁻³ , that is, the number of balls Z is relatively large. The thickness in the circumferential direction of the column part 32 cannot be increased with respect to the standard bearing. Therefore, as the circumferential thickness of the pillar portion 32 becomes thinner, the thickness of the corner portion 35 becomes thinner. Therefore, as shown by an arrow A in FIG. 6, when the ball 3 and the corner portion 35 of the cage 30 hit each other, the corner portion 35 is likely to spread in the circumferential direction, and as a result, the axial movement amount ΔA of the cage. Becomes larger. As a result, the axial distance ΔS1 between the cage 30 and the inner ring 20 is reduced, and the possibility that the cage 30 and the inner ring 20 interfere with each other increases. If the radial cross-sectional shape of the pocket portion 33 of the cage 30 is a shape that does not have the second straight shape portion 33c, the axial distance ΔS1 between the cage 30 and the inner ring 20 is narrowed and retained. The possibility that the container 30 and the inner ring 20 interfere with each other increases. Therefore, as in the angular ball bearing 1 of the present embodiment, the axial distance ΔS1 between the cage 30 and the inner ring 20 can be increased by forming the second straight shape portion 33c in the pocket portion 33. It is possible to reduce the possibility that the cage 30 and the inner ring 20 interfere with each other.

As shown in FIG. 12, even when the radial cross-sectional shape of the pocket portion 33 of the cage 30 is a conventional circular shape having an arbitrary radius r1, the same as the cage 30 of the present embodiment described above. The axial relative movement amount ΔA of the cage 30 increases during the rotation of the bearing. And when the radial direction cross-sectional shape of the pocket part 33 of the holder | retainer 30 is circular, as shown in FIG. 14, the radial direction inner edge part 33d which is a part which guides the ball | bowl 3 of the pocket part 33, and a ball | bowl 3 is a point contact. In this case, as shown in FIG. 13, the radial distance between the radially inner edge 33 d of the pocket 33 and the ball 3 is the radial movement amount ΔR of the cage 30.

In this case, since the cage 30 and the ball 3 are in point contact, the cage 30 easily moves in the axial direction relative to the inner ring 20 or the outer ring 10 during the bearing rotation. As a result, the radial direction of the pocket portion 33 The location where the inner edge 33d is in point contact with the ball 3 also moves in the axial direction. In FIG. 12, the pocket part 33 (column part 32) which moved to the axial direction is shown with the broken line. Then, since the radial distance between the radially inner edge 33d of the pocket portion 33 and the ball 3 is smaller after the movement than before the movement in the axial direction, the radial movement amount ΔR of the cage 30 is reduced. Also, after movement (see the broken line in FIG. 13) is smaller than before movement in the axial direction (see the solid line in FIG. 13). Further, when the axial position of the cage 30 moves in the direction opposite to the above from the position indicated by the solid line in FIG. 12 (moves in the direction opposite to the direction indicated by the broken line in FIG. 12 (left side)), the pocket portion The radial distance (radial motion amount ΔR) between the radial inner edge 33d of 33 and the ball 3 is reduced.

This phenomenon occurs every time the cage 30 moves relative to the inner ring 20 or the outer ring 10 in the axial direction (that is, from the neutral state where the ball center Oi and the spherical center position of the pocket portion 33 coincide during rotation). When the cage 30 is relatively displaced to the left or right in the axial direction, the radial movement amount ΔR of the cage 30 is frequently changed in a direction in which the cage 30 becomes smaller. When the ball is circular, the ball 3 cannot be stably guided, and the vibration of the cage 30 increases or the cage 30 and the ball 3 are stuck against each other. Problems such as early breakage of the vessel 30 occur.

Therefore, as shown in FIG. 15, the first straight portion 33 b is provided in the radial cross-sectional shape of the pocket portion 33, as shown in FIG. The straight shape portion 33b and the ball 3 are configured to be in line contact with each other in an arc shape. In this way, by bringing the contact portion between the cage 30 and the ball 3 into contact with the line, when the cage 30 moves in the radial direction, the ball 3 fits into the pocket portion 33 flexibly, Axial relative movement can be suppressed. Therefore, a change in the radial movement amount ΔR of the cage 30 can be prevented, and an increase in vibration during rotation of the bearing can be suppressed. In addition, as a result of the axial movement of the cage 30 being suppressed, problems such as cage noise and early breakage of the cage 30 can be suppressed.

When the radial cross-sectional shape of the pocket portion 33 of the cage 30 is circular (see FIG. 12), there are problems that may occur in addition to the problems that occur during the rotation of the bearing described above. The problem is that the radial movement amount ΔR of the cage 30 is designed by the relative shift of the position of the pitch circle of the pocket portion 33 of the cage 30 and the position of the pitch circle of the ball 3 in the axial direction. It varies from the above range, and it is difficult to accurately measure the ball circumscribed circle diameter and the ball inscribed circle diameter at the time of manufacturing the cage.

As one method of measuring the ball circumscribed circle diameter and the ball inscribed circle diameter of the cage 30, the ball 3 is fixed by applying a light measurement load radially inward with the ring portion 31 of the cage 30 down. There is a method to measure. At this time, the ball 3 in the pocket portion 33 approaches the ring portion 31 in the pocket portion 33 by gravity. As a result, the position of the pitch circle of the pocket portion 33 and the position of the pitch circle of the ball 3 are relatively shifted in the axial direction. As a result, the radial movement amount ΔR of the cage 30 becomes smaller after movement (see the broken line in FIG. 13) than before movement in the axial direction (see the solid line in FIG. 13). ΔR becomes smaller than the design range. In this case, it becomes difficult to accurately measure the ball circumscribed circle diameter and the ball inscribed circle diameter of the cage 30.

Therefore, in the present embodiment, by providing the first straight shape portion 33b in the radial cross-sectional shape of the pocket portion 33, as shown in FIG. 15, the ball 3 fits into the straight shape portion 33b due to the measurement load, It is easy to accurately measure the ball circumscribed circle diameter and the ball inscribed circle diameter without the ball 3 being displaced in the axial direction.

Further, when the cage 30 is manufactured by injection molding, the mold has an axial draw type structure, but when the mold forming the pocket portion 33 is released, the corner portion 35 of the column portion 32 (see FIG. 6). .) The vicinity is forcibly removed, and when removing the mold from the pocket portion 33, the cage cannot be released unless it is positioned and removed in the axial direction.

Here, in the case of the conventional deep groove ball bearing 100 shown in FIG. 8, as shown in FIGS. 16 and 17, the cage 130 has a substantially annular ring portion 131 and a shaft spaced from the ring portion 131 at a predetermined interval. The crown-shaped cage has a plurality of column portions 132 protruding in the direction and a plurality of pocket portions 133 formed between adjacent column portions 132.

In the conventional deep groove ball bearing 100, since the number of balls is not large, the pitch in the circumferential direction of the pocket portion 133 of the cage 130 is wide, and the gap between the pair of corner portions 135 of the column portion 132 is the same as that of this embodiment. The column portions 32 are spaced apart from each other between the pair of corner portions 35. Therefore, the concave portion 136 can be provided between the pair of corner portions 135 for the purpose of easily deforming the tip portion of the column portion 132 when the mold is not removed. The bottom surface 137 of the recess 136 can be a plane extending in the circumferential direction. Then, a pin for punching is provided on the bottom surface 137 of the recess 136, and the pin is pushed out in the axial direction with respect to the die of the pocket portion 133, so that it is possible to release the die without forcing.

However, when the number of balls is large as in the cage 30 of the present embodiment and the pitch in the circumferential direction of the pocket portion 33 (distance L between the balls) is narrow, as shown in FIG. A substantially V-shaped cutout 34 is formed between them, and it is difficult to form a flat surface at the bottom of the cutout 34. The circumferential width of the bottom plane of the notch 34 is desirably 0.2 mm or more in consideration of the processing limit of the V-shaped sharp portion at the tip of the die where the notch 34 is injection-molded.

Therefore, if the radially inner side surface 31a and the radially outer side surface 31b of the ring portion 31 of the cage 30 have a cross-sectional planar shape (annular shape), the mold parts that form the pocket portion 33 are forcibly removed. At this time, since there is no catch between the retainer 30 and the mold that forms the retainer main body (the mold that forms the inner diameter, outer diameter, and end surface of the ring portion 31 of the retainer 30), the pocket The mold parts forming the part cannot be forcibly removed.

Therefore, as shown in FIG. 1 and FIG. 7, in the cage 30 of the present embodiment, an inner convex portion 38 that protrudes radially inward is formed on the radially inner side surface 31 a (one radial side surface) of the ring portion 31. Form. In this way, the inner convex portion 38 is formed as a catch between the cage 30 and the mold that forms the cage main body, so that the mold parts that form the pocket portion 33 can be forcibly removed. can do.

The shape and position of the inner convex portion 38 are not particularly limited, and may be formed so as to protrude radially inward from the front side end portion of the radial inner side surface 31a of the ring portion 31 as shown in FIG. Absent. However, in order to avoid contact between the inner ring 20 and the inner convex portion 38 when the cage 30 tilts during bearing rotation, the convex portion 38 is desirably provided in the vicinity of the center of the ring portion 31 excluding the axial end portion. . That is, from the viewpoint of avoiding the contact of the inner ring convex portion 38, the position of the inner convex portion 38 shown in FIG. 7 is more desirable than the position of the inner convex portion 38 shown in FIG.

Further, when the size of the cage 30 to be manufactured is large, if the radial dimension of the inner convex portion 38 is increased, the holding force at the time of releasing can be increased, but contact between the inner ring 20 and the inner convex portion 38 occurs. The radial dimension of the inner convex portion 38 has a limit. Therefore, in such a case, as shown in FIG. 19, it is desirable to increase the holding force at the time of mold release by setting the number of the inner convex portions 38 to a plurality (two in FIG. 19).

Further, as shown in FIG. 20, the inner convex portion 38 is not provided, and the outer convex portion 39 that protrudes radially outward may be formed on the radially outer side surface 31 b (the other radial side surface) of the ring portion 31. . Also in this case, the shape, position, number, and the like of the outer convex portions 39 are appropriately set.

Although not shown, both the inner convex portion 38 and the outer convex portion 39 may be formed.

It should be noted that the spherical center position of the pocket portion 33 is not limited to the configuration shifted radially inward with respect to the radial center of the ring portion 31, and may be configured so as to be shifted radially outward as shown in FIGS. I do not care. That is, the ring portion 31 is disposed between the outer ring groove shoulder 12 and the inner ring counter bore 23, the column portion 32 is disposed between the raceway surfaces 11 and 21 of the outer ring 10 and the inner ring 20, and the inner side in the radial direction of the column portion 32. It is good also as a structure where the ring part 31 connects to an edge part. Even in this case, since the notch 34 is provided in the middle in the circumferential direction at the tip of the column 32 and is divided into two parts, the pocket 33 is formed when the retainer 30 is manufactured by injection molding. It is possible to prevent the corner portion 35 on the pocket portion 33 side of the column portion 32 from being damaged by forcibly removing the mold parts forming the.

Here, the radial cross-sectional shape of the pocket portion 33 is an arbitrary radius r composed of an arc connecting the radial outer side surface (radial one side surface) 31b of the ring portion 31 and the radial inner side surface (radial other side surface) 31a. It is assumed to be a circle. The arc 33a is a first straight-shaped portion 33b extending in the axial direction by cutting out a radially outer portion (one radial portion). The first straight shape portion 33b is disposed on the front side of the center P of the circle. Further, the arc 33a has a second straight shape in which a portion connecting the end portion on the back surface side of the first straight shape portion 33b and the end portion on the front surface side of the radially outer side surface 31b of the ring portion 31 is notched. Part 33c. Therefore, the 2nd straight shape part 33c is made into the linear shape which goes to a radial inside as it goes to the back side (ring part 31 side). Further, the first straight shape portion 33b is formed so that the center Oi of the ball 3 (spherical center of the pocket portion 33) overlaps the first straight shape portion 33b in the axial direction.

An inner convex portion 38 that protrudes radially inward is formed on the radially inner side surface 31 a (the other radial side surface) of the ring portion 31. In this way, the inner convex portion 38 is formed as a catch between the cage 30 and the mold that forms the cage main body, so that the mold parts that form the pocket portion 33 can be forcibly removed. can do. Also in this cage 30, an outer convex portion 39 (see FIG. 20) protruding radially outward may be formed on the radially outer surface 31b (one radial side surface) of the ring portion 31.

Even in such a configuration, it is possible to achieve the same effects as the above-described embodiment.

Next, each embodiment in which a plurality of parameters of the angular ball bearing 1 are changed will be described.

Example 1
In the angular ball bearing 1 of this example, the inner diameter is Φ15 mm, the contact angle α is 50 °, and the value of Ai (the radial height Hi of the inner ring groove shoulder 22 is divided by the diameter Dw of the ball 3) is 0. .38, Ae (the radial height He of the outer ring groove shoulder 12 divided by the diameter Dw of the ball 3) was set to 0.38. The cage 30 has the shape shown in FIG. 18, and the material thereof is a polyamide resin. The relationship between the inter-ball distance L and the ball pitch 3 pitch circumference length πdm obtained by multiplying the ball pitch circle diameter dm by the circumference ratio π satisfies L / πdm = 12 × 10 ⁻³ .

It was confirmed that by setting each parameter in this way, the same effects as those of the above-described embodiment can be obtained.

(Example 2)
In the angular ball bearing 1 of this embodiment, the inner diameter is Φ60 mm, the contact angle α is 60 °, and Ai (the radial height Hi of the inner ring groove shoulder 22 is divided by the diameter Dw of the ball 3) is 0. .47, Ae (the radial height He of the outer ring groove shoulder 12 divided by the diameter Dw of the ball 3) was set to 0.47. The cage 30 has the shape shown in FIG. 1, and the material thereof is a material in which the base resin is polyacetal resin and carbon fiber is added as a reinforcing material by 10 weight percent. The relationship between the inter-ball distance L and the ball pitch pitch diameter πdm obtained by multiplying the ball pitch circle diameter dm by the circumference ratio π satisfies L / πdm = 2.3 × 10 ⁻³ .

Example 3
In the angular ball bearing 1 of the present embodiment, the inner diameter is Φ40 mm, the contact angle α is 55 °, and the value of Ai (the radial height Hi of the inner ring groove shoulder 22 is divided by the diameter Dw of the ball 3) is 0. .43, Ae (the radial height He of the outer ring groove shoulder 12 divided by the diameter Dw of the ball 3) was set to 0.43. The cage 30 has the shape shown in FIG. 20, and the material thereof is a base resin made of polyamide resin, and 20 weight percent of glass fiber is added as a reinforcing material. The relationship between the inter-ball distance L and the ball 3 pitch circumferential length πdm obtained by multiplying the ball pitch circle diameter dm by the circumferential ratio π satisfies L / πdm = 7.0 × 10 ⁻³ .

Example 4
In the angular ball bearing 1 of the present embodiment, the inner diameter is Φ40 mm, the contact angle α is 55 °, and the value of Ai (the radial height Hi of the inner ring groove shoulder 22 is divided by the diameter Dw of the ball 3) is 0. .43, Ae (the radial height He of the outer ring groove shoulder 12 divided by the diameter Dw of the ball 3) was set to 0.43. The cage 30 has the shape shown in FIG. 19, and the material thereof is a base resin made of polyamide resin and glass fiber added as a reinforcing material by 20 weight percent. The relationship between the inter-ball distance L and the ball 3 pitch circumferential length πdm obtained by multiplying the ball pitch circle diameter dm by the circumferential ratio π satisfies L / πdm = 7.0 × 10 ⁻³ .

It should be noted that the present invention is not limited to the above-described embodiment, and can be changed or improved as appropriate.

This application is based on Japanese Patent Application No. 2014-068945 filed on Mar. 28, 2014, the contents of which are incorporated herein by reference.

1 angular contact ball bearing 3 ball 10 outer ring 11 raceway surface 12 outer ring groove shoulder 13 outer ring counterbore 14 outer ring chamfer 20 inner ring 21 raceway surface 22 inner ring groove shoulder 23 inner ring counterbore 24 inner ring chamfer 30 cage 31 ring part 31a radially inward Side (radial one side, radial other side)
31b Radial outer surface (radial other side surface, radial one side surface)
32 Pillar part 33 Pocket part 33a Arc 33b 1st straight shape part 33c 2nd straight shape part 33d Radial direction inner side edge part 34 Notch part 35 Corner | angular part 38 Inner convex part (convex part)
39 Outer convex part (convex part)
Oi ball center (spherical center of pocket)

Claims

An outer ring having a raceway surface on the inner peripheral surface;
An inner ring having a raceway surface on the outer peripheral surface;
A plurality of balls disposed between the raceways of the outer ring and the inner ring;
Holding the ball so as to roll freely, a cage that is a ball guide system,
An angular contact ball bearing comprising:
On the outer peripheral surface of the inner ring, an inner ring counterbore is recessed on the back side, and an inner ring groove shoulder is protruded on the front side,
On the inner peripheral surface of the outer ring, an outer ring counter bore is recessed on the front side, and an outer ring groove shoulder is protruded on the back side,
The contact angle α of the balls is 45 ° ≦ α ≦ 65 °,
When Ai is obtained by dividing the radial height of the inner ring groove shoulder by the diameter of the ball, 0.35 ≦ Ai ≦ 0.50,
When Ae is obtained by dividing the radial height of the outer ring groove shoulder by the diameter of the ball, 0.35 ≦ Ae ≦ 0.50,
The cage is formed between a substantially annular ring portion, a plurality of column portions protruding in the axial direction at a predetermined interval from the front side or the back side of the ring portion, and a plurality of adjacent column portions. And a pocket-shaped cage having
The spherical center position of the pocket portion is shifted to one radial side with respect to the radial center of the ring portion,
The radial cross-sectional shape of the pocket portion is a circle with an arbitrary radius composed of an arc connecting the one radial side surface and the other radial side surface of the ring portion,
The angular ball bearing according to claim 1, wherein at least one convex portion projecting in the radial direction is formed on at least one of the one radial side surface and the other radial side surface of the ring portion.
2. The angular ball bearing according to claim 1, wherein the circular arc is a first straight shape portion that is notched at one end portion in the radial direction and extends in the axial direction.
3. The arc according to claim 2, wherein a portion connecting the first straight shape portion and the one side surface in the radial direction of the ring portion is cut out to form a second straight shape portion. Angular contact ball bearing described.
The relationship between the distance L between the adjacent balls and the ball pitch circumferential length πdm obtained by multiplying the ball pitch circle diameter dm by the circumferential ratio π is 2.5 × 10 −3 ≦ L / πdm ≦ 13 × The angular ball bearing according to any one of claims 1 to 3, wherein 10-3 is satisfied.