Angular contact ball bearings

Abstract

To provide an angular ball bearing capable of being easily assembled to an inner member of a retainer and preventing separation of the retainer from the inner member after the assembling.SOLUTION: An angular ball bearing 1 includes: an outer member 2; an inner member 4; a ball 6 disposed between the outer member 2 and the inner member 4; and a retainer 8 for retaining the ball 6. The outer member 2 is detachable from an assembly component As composed of the inner member 4, the ball 6 and the retainer 8. A radial distance M from a groove bottom 4aa of a raceway groove 4a of the inner member 4 to a counter bore portion 4b of the inner member 4 is 0.2-0.7% of a pitch circle diameter P of the ball 6, and an axial dimension Z of the counter bore portion 4b of the inner member 4 is 8-20% of a diameter Dw of the ball 6. The inner member 4 has a first step portion 10 adjacent to the counter bore portion 4b and gradually reduced in diameter from the counter bore portion 4b on its outer peripheral face, and a height X of the first step portion 10 is 0.1-0.5% of a pitch circle diameter of the ball 8.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an angular contact ball bearing with a separate outer member. [Background technology]

[0002] Angular contact ball bearings generally have an inner member, outer member, balls (rolling elements), and cage that cannot be separated, but depending on the conditions of use, angular contact ball bearings with a separable outer member may be used. In this case, for example, the outer member is separated and installed in a housing, and the inner member, balls, and cage are installed as an assembly on the shaft, and then the shaft and housing are combined. In this case, the outer member of the bearing is easy to separate, and after the outer member is separated, the inner member, balls, and cage are assembled into an assembly, making assembly easy.

[0003] In such angular contact ball bearings with a separate outer member, the counterbore diameter of the inner member is made larger than the inscribed circle diameter of the balls held in the cage, which is separated from the inner member, so that the cage and balls are less likely to come off the inner member after assembly. Therefore, when assembling the bearing, the cage, which holds the balls separated from the inner member, is elastically deformed so that the balls climb over the counter portion of the inner member and is then assembled to the inner member.

[0004] When the cage of an angular contact ball bearing with a separate outer member is made of a synthetic resin that easily deforms elastically, such as nylon, it is easy to assemble the cage to the inner member. However, if the assembly part separated from the outer member is oriented with its axial direction facing vertically, the cage may bend due to the weight of the balls, causing it to come off the inner member along with the balls, and the assembly part may come apart. This requires great care when assembling the bearing or installing it in a machine, which reduces work efficiency.

[0005] Therefore, in some angular contact ball bearings with a separate outer member, the difference in size between the outer diameter of the counterbore of the inner member and the inscribed circle diameter of the ball is set to 5 to 20% of the ball diameter (Patent Document 1).In the angular contact ball bearing of Patent Document 1, the balls will not come off the inner member even if they are deflected by a force equivalent to their own weight. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-285318 Summary of the Invention [Problem to be solved by the invention]

[0007] However, the angular contact ball bearing in Patent Document 1 is designed to use a cage made of synthetic resin, which is prone to elastic deformation, and it is difficult for a steel cage or a synthetic resin cage, which is highly rigid and not prone to elastic deformation, to overcome the counterbore. Also, if the width of the inner member is increased, the cage must be significantly deformed, making assembly difficult.

[0008] An object of the present invention is to provide an angular contact ball bearing in which the retainer can be easily assembled to the inner member and the retainer will not separate from the inner member after assembly. [Means for solving the problem]

[0009] The angular contact ball bearing of the present invention comprises an outer member, an inner member, balls that are rolling elements interposed between the outer member and the inner member, and a cage that holds the balls, wherein the outer member is separable from an assembly consisting of the inner member, the balls, and the cage, wherein the radial distance M from the bottom of the raceway groove of the inner member to the counterbore portion of the inner member is 0.2 to 0.7% of the pitch circle diameter of the balls, the axial dimension Z of the counterbore portion of the inner member is 8 to 20% of the diameter Dw of the balls, and the inner member has on its outer peripheral surface a first step that is adjacent to the counterbore portion of the inner member and has a diameter smaller than that of the counterbore portion of the inner member, and the height X of the first step is 0.1 to 0.5% of the pitch circle diameter of the balls.

[0010] With this configuration, by providing a step in the counterbore portion of the inner member, when assembling the cage and balls, the balls are guided into the counterbore portion by the small diameter portion, making it easier to assemble the balls and cage into the inner member. In other words, by setting the height of the first step in the counterbore portion of the inner member to 0.1 to 0.5% of the pitch circle diameter of the balls and setting the axial dimension of the counterbore portion of the inner member to 8 to 20% of the diameter of the balls, it becomes easier to assemble the cage and balls into the inner member. Furthermore, by setting the radial distance from the groove bottom of the raceway groove in the inner member to the counterbore portion of the inner member to 0.2 to 0.7% of the pitch circle diameter of the balls, after assembly, the cage will not come off the inner member even if it bends due to a force equivalent to the weight of the balls.

[0011] Furthermore, by making the axial dimension of the counterbore portion of the inner member 8 to 20% of the ball diameter, the amount of deformation of the cage is suppressed, shortening the deformation time. As a result, it is possible to incorporate a steel cage or a highly rigid plastic cage, and there is little risk of the cage coming off the inner member and disassembling after assembly. This also makes it easier to attach and detach the outer member to the assembly parts, improving the ease of assembly of the bearing. In this way, the cage and balls are easily attached to the inner member, and the cage is unlikely to separate from the inner member after assembly, making it easier to handle during assembly and when installing it in a machine, and improving work efficiency.

[0012] In the present invention, the first step may be an inclined surface. According to this configuration, by making the first step an inclined surface, the cage and the balls can smoothly climb over the counterbore portion of the inner member, improving assembly efficiency.

[0013] In the present invention, the outer member may have, on its inner peripheral surface, a second step adjacent to the raceway groove of the outer member and larger in diameter than the raceway groove of the outer member, and the height Y of the second step may be 0.1 to 0.5% of the pitch circle diameter of the ball. In this case, the outer member may have a straight portion in the raceway groove of the outer member adjacent to the second step. With this configuration, the outer member can be smoothly separated from and incorporated into the assembly part. This improves the ease of assembly of the bearing. [Effects of the Invention]

[0014] According to the angular contact ball bearing of the present invention, the retainer can be easily assembled to the inner member regardless of the material of the retainer, and the retainer will not separate from the inner member after assembly, which makes it easier to handle and improves work efficiency when assembling or installing it in a machine. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a cross-sectional view showing an angular contact ball bearing according to a first embodiment of the present invention. [Figure 2] 1A is an enlarged cross-sectional view of the outer member of the angular contact ball bearing, and FIG. 1B is an enlarged view of part B in FIG. [Figure 3] 5A to 5C are diagrams showing a procedure for assembling the retainer and balls of the angular contact ball bearing to the inner member. [Figure 4] 10 is a view showing a state in which the outer member of the angular ball bearing is assembled to an assembly part. FIG. [Figure 5] FIG. 2 is a cross-sectional view showing the shape of the bearing that was evaluated. DETAILED DESCRIPTION OF THE INVENTION

[0016] A preferred embodiment of the present invention will now be described with reference to the drawings. In the following description, the terms "axial direction," "radial direction," and "circumferential direction" refer to the "axial direction," "radial direction," and "circumferential direction" of the bearing, respectively.

[0017] Fig. 1 is a cross-sectional view showing an angular contact ball bearing 1 according to a first embodiment of the present invention. The angular contact ball bearing 1 of this embodiment is an outer member separable angular contact ball bearing comprising an outer member 2, an inner member 4, a plurality of balls 6 which are a type of rolling element interposed between the outer member 2 and the inner member 4, and a cage 8 which holds the balls 6, and the outer member 2 can be separated from an assembly part As which consists of the inner member 4, balls 6 and cage 8. In this embodiment, the outer member 2 is fitted into a housing Ho (Fig. 4), and the inner member 4 is fitted onto a shaft Sh (Fig. 4).

[0018] The cage 8 of this embodiment is an annular cage made of synthetic resin, and has circular pockets 8a formed at equal intervals in the circumferential direction, which can freely accommodate the balls 6 from the inner periphery side. The material of the cage 8 is, for example, PA9T+GF30% (30% glass-filled polyamide 9T). However, the material of the cage 8 is not limited to this.

[0019] The inner member 4 has a raceway groove 4a on its outer circumferential surface. Balls 6 roll in this raceway groove 4a. The inner member 4 also has a counterbore portion 4b on one axial side (left side in FIG. 1) of the raceway groove 4a on its outer circumferential surface. The counterbore portion 4b is a portion where the shoulder of the raceway groove 4a is cut away, and has a smaller diameter than the opposite counterbore portion 4c (right side in FIG. 1). The counterbore portion 4b extends in the axial direction from the raceway groove 4a toward one end face 4d of the inner member 4.

[0020] The inner member 2 has a first step 10 on its outer circumferential surface that is adjacent to the counterbore 4b and has a smaller diameter than the counterbore 4b. That is, the outer circumferential surface of the inner member 2 is formed with the counterbore 4b that connects to the raceway groove 4a via the first step 10, and a small diameter portion 4e that connects to one end face 4d. The small diameter portion 4e also extends in the axial direction.

[0021] In this embodiment, the first step 10 has an inclined surface 10a. The inclined surface 10a is inclined so that the diameter decreases from the counterbore portion 4b toward the small diameter portion 4e. However, the first step 10 is not limited to being inclined, and the inclined surface may be a step that extends radially.

[0022] When the pitch circle diameter (PCD) of the ball 6 is P and the diameter of the ball 6 is Dw, the dimensions of the raceway groove 4a, counterbore portion 4b and first step 10 of the inner member 4 are set as follows.

[0023] The radial distance M from the groove bottom 4aa of the raceway groove 4a of the inner member 4 to the counterbore portion 4b is 0.2 to 0.7% (M = 0.002P to 0.007P) of the pitch circle diameter P of the ball 6. Here, the groove bottom 4aa of the raceway groove 4a is the most recessed part of the raceway groove 4a, that is, the part with the smallest diameter.

[0024] The axial dimension Z of the counterbore portion 4b of the inner member 4 is 8 to 20% of the diameter Dw of the ball 6 (Z=0.08Dw to 0.20Dw). The height X of the first step 10 is 0.1 to 0.5% of the pitch circle diameter P of the ball 6 (X=0.001P to 0.005P).

[0025] The outer member 2 has a raceway groove 2a on its inner peripheral surface. Balls 6 roll in this raceway groove 2a. The outer member 4 also has a counterbore portion 2b on the other axial side (right side in FIG. 1) of the raceway groove 2a on its inner peripheral surface. The counterbore portion 2b is a portion where the shoulder of the raceway groove 2a is cut away, and has a larger diameter than the opposite counterbore portion 2c (left side in FIG. 1). The counterbore portion 2b extends in the axial direction from the raceway groove 2a to the other end face 2d of the outer member 4.

[0026] The outer member 2 has, on its inner peripheral surface, a second step 12 adjacent to the raceway groove 2a and having a larger diameter than the raceway groove 2a. In other words, the raceway groove 2a of the outer member 2 and the counterbore portion 2b are connected via the second step 12. The height Y of the second step 12 is 0.1 to 0.5% of the pitch circle diameter P of the balls 6 (Y = 0.001P to 0.005P).

[0027] Fig. 2(A) is an enlarged cross-sectional view of the outer member 2, and Fig. 2(B) is an enlarged view of portion B in Fig. 2(A). As shown in Fig. 2(B), the outer member 2 has a straight portion 14 in a portion of its raceway groove 2a adjacent to the second step 12. The straight portion 14 extends in the axial direction from a groove bottom 2aa of the raceway groove 2a toward the second step 12. The straight portion 14 lies in the range indicated by R in Fig. 2(A). Here, the groove bottom 2aa of the raceway groove 2a is the most recessed portion of the raceway groove 2a, i.e., the portion with the largest diameter.

[0028] Figure 3 shows the procedure for assembling the cage 8 and balls 6 to the inner member 4. Figure 3(A) shows the state in which the balls 6 are placed on the small diameter portion 4e of the inner member 4. In this state, there is a pocket gap between the cage 8 and the balls 6, and the cage 8 is not elastically deformed. Figure 3(B) shows the state in which the balls 6 are placed on the inclined surface 10a of the first step 10 of the inner member 4. In this state, the pocket gap gradually decreases.

[0029] Figure 3(C) shows the state in which the balls 6 rest on the counterbore portions 4b of the inner member 4. In this state, there is no pocket clearance between the cage 8 and the balls 6, and the cage 8 is elastically deformed. Figure 3(D) shows the state in which the balls 6 have climbed over the counterbore 4b and are fitted into the raceway grooves 4a, i.e., the state in which the assembly part As of the inner member 4, balls 6, and cage 8 is completed. In this state, there is a pocket clearance between the cage 8 and the balls 6.

[0030] 3(C) for a long time, the retainer 8 exceeds its elastic range, making assembly difficult. Alternatively, the retainer 8 may be plastically deformed, and even if it overcomes the counterbore portion 4b, it may come off.

[0031] In this embodiment, the axial dimension Z of the counterbore portion 4b of the inner member 4 is set to 8 to 20% of the diameter Dw of the balls 6. This reduces the amount of elastic deformation of the cage 8 and shortens the deformation time. As a result, plastic deformation of the cage 8 can be prevented. That is, even if the width A (axial dimension) of the inner member 4 is large, the cage 8 and balls 6 can be assembled into the inner member 4. Moreover, because the cage 8 does not undergo plastic deformation, the assembled cage 8 and balls 6 will not come off the inner member 3. Furthermore, regardless of the shape of the cage 8, even a cage 8 made of a material that is not easily elastically deformed can be easily assembled into the inner member 4.

[0032] Figure 4 shows the state in which the outer member 2 is assembled into the assembly part As. Figure 4(A) shows a bearing in which the outer member 2 has a counterbore portion 2b, and Figure 4(B) shows a bearing in which the outer member 2 does not have a counterbore portion 2b.

[0033] 4(A), the second step 12 of the counterbore 2b of the outer member 2 functions as a spigot, allowing the balls 6 to be guided up to the raceway groove 2a. Also, because the outer member 2 has a counterbore 2b, there is play between the center C1 of the inner diameter of the inner member 2 and the center C2 of the outer diameter of the outer member, making assembly easy.

[0034] On the other hand, in the bearing of Figure 4(B), there is no second step 12 or counterbore portion 2b, so in order to avoid contact between the outer member 2 and the balls 6, it is necessary to precisely align the center C1 of the inner diameter of the inner member 2 with the center C2 of the outer diameter of the outer member. Also, since the outer member 2 is incorporated into the housing Ho and the inner member 4 is assembled in a state where it is incorporated into the shaft Sh, the weight of the inner member 4 is heavy by the weight of the shaft Sh and other parts. Therefore, if the balls 6 come into contact with the outer member 2, the balls 6 are more likely to be damaged, which may shorten the life of the bearing.

[0035] The assembly ease (ease of assembling the retainer 8 to the inner member 4) and handling ease after assembly (difficulty of disassembling the assembly part As after assembly) were evaluated depending on whether or not the first step 10 was present in the shape of the retainer of the angular ball bearing shown in Figure 5 and the material of the retainer of the angular ball bearing shown in Table 1.

[0036] The cage shape (1) in Fig. 5(A) is the same annular cage as in the above embodiment. The cage shape (2) in Fig. 5(B) is a crown-shaped cage made of synthetic resin. The cage shape (3) in Fig. 5(C) is a steel plate-shaped cage. In Examples 1 and 2 and Comparative Example 1 in Table 1, a cage 8 with cage shape (1) is used. In Examples 3 and 4 and Comparative Example 2, a cage 8 with cage shape (2) is used. In Example 5 and Comparative Example 3, a cage 8 with cage shape (3) is used.

[0037] As for the material of the resin cage 8, PA66+GF30% (30% glass-filled nylon 66) was selected as a representative example of a soft material, and PA9T+GF30% (30% glass-filled polyamide 9T) was selected as a representative example of a hard material. A steel plate (SPCC) cage was also evaluated as a comparison with the resin cage. In Examples 1 and 3 and Comparative Example 1 in Table 1, a cage 8 made of PA66+GF30% was used. In Examples 2 and 4 and Comparative Example 2, a cage 8 made of PA9T+GF30% was used. In Example 5 and Comparative Example 3, a steel plate (SPCC) cage 8 was used.

[0038] In Table 1, "◎" indicates that it is possible to implement and highly effective. "○" indicates that it is possible to implement, but its performance is inferior to "◎". "△" indicates that it is possible to implement, but its performance is inferior to "○". "×" indicates that it is less effective.

[0039] [Table 1]

[0040] As in Examples 1 to 5, by setting the height X of the first step 10 of the inner member 4 to 0.1 to 0.5% of the pitch circle diameter of the balls and the axial dimension Z of the counterbore portion 4b of the inner member 4 to 8 to 20% of the diameter Dw of the balls 6, assembly is possible regardless of the shape and material of the cage. Furthermore, by setting the radial distance Z from the groove bottom 4aa of the raceway groove 4a of the inner member 4 to the counterbore portion 4b to 0.2 to 0.7% of the pitch circle diameter P of the balls 6, the inner member 4 is less likely to disassemble after assembly, improving workability.

[0041] In particular, it was confirmed that both ease of assembly and ease of handling after assembly were excellent in Examples 2, 4, and 5, which used a cage 8 made of a hard material. In Comparative Example 1, which used a soft cage 8, assembly was possible and the ease of handling was not poor, but the effects were inferior compared to Examples 1 to 5. In Comparative Examples 2 and 3, which used a cage 8 made of a hard material, no effects were observed in either ease of assembly or ease of handling.

[0042] According to the above configuration, by providing the first step 10 in the counterbore portion 4b of the inner member 4 shown in FIG. 1, when assembling the cage 8 and balls 6 shown in FIG. 3, the balls 6 are guided into the counterbore portion 4b by the small diameter portion 4e, making it easier to assemble the balls 6 and cage 8 into the inner member 4. In other words, by setting the height X of the first step 10 of the inner member 4 in FIG. 1 to 0.1 to 0.5% of the pitch circle diameter P of the balls 9 and setting the axial dimension Z of the counterbore portion 4b of the inner member 4 to 8 to 20% of the diameter Dw of the balls 6, it becomes easier to assemble the cage 8 and balls 6 into the inner member 4. Furthermore, by setting the radial distance M from the groove bottom 4aa of the raceway groove 4a of the inner member 4 to the counterbore portion 4b to 0.2 to 0.7% of the pitch circle diameter P of the balls 6, the cage 8 will not come off the inner member 4 after assembly, even if it bends due to a force equivalent to the weight of the balls 6.

[0043] Furthermore, by setting the axial dimension Z of the counterbore portion 4b of the inner member 4 to 8-20% of the ball diameter Dw, the amount of deformation of the cage 8 is suppressed, shortening the deformation time. As a result, it is possible to incorporate a steel cage or a highly rigid resin cage such as polyether ether ketone resin (PEEK), polyphenylene sulfide (PPS), or polyamide 9T (PA9T), and there is little risk of the cage 8 coming off the inner member 4 and disassembling after assembly. This also makes it easier to attach and detach the outer member 2 to the assembly parts As, improving the ease of assembly of the bearing. In this way, the cage 8 and balls 6 are easily attached to the inner member 4, and the cage 8 is unlikely to separate from the inner member 4 after assembly, making it easier to handle during assembly and installation into a machine, improving work efficiency.

[0044] Furthermore, since the first step 10 has an inclined surface 10a, the cage 8 and the balls 6 can smoothly climb over the counterbore portion 4b of the inner member 4, improving the ease of assembly.

[0045] The outer member 2 has a second step 12 on its inner peripheral surface, and the height Y of the second step 12 is 0.1 to 0.5% of the pitch circle diameter P of the balls 6. As shown in Figure 4(A), when reassembling after separation, the counterbore portion 2b of the outer member 2 serves as a spigot to guide the balls 6 to the raceway grooves 2a, making assembly easy. Furthermore, because the outer member 2 has the counterbore 2b, there is play between the center C1 of the inner diameter of the inner member 2 and the center C2 of the outer diameter of the outer member, making assembly easy.

[0046] As shown in Figure 3, the outer member 2 has a straight portion 14 that connects to the second step 12 of the counterbore portion 2b. This allows the balls 6 to be separated without getting caught, and also allows the outer member 2 to be smoothly incorporated into the assembly part As. This improves the ease of assembly of the bearing.

[0047] The present invention is not limited to the above-described embodiments, and various additions, modifications, and omissions are possible without departing from the spirit of the present invention. Therefore, such additions, modifications, and omissions are also included in the scope of the present invention. [Explanation of symbols]

[0048] 1 Angular contact ball bearing 2 Outer member 2a Outer member raceway groove 4 Inner member 4a Raceway groove of inner member 4aa Bottom of inner member raceway groove 4b Counterbore portion of inner member 6 balls 8 Cage 10 First Step 10a Slope 12 Second Step 14 Straight section As Assembly parts Dw ball diameter M radial distance P: Ball pitch diameter X Height of the first step Y Second step height Z Axial dimension of the counterbore of the inner member

Claims

1. An angular contact ball bearing comprising an outer member, an inner member, balls as rolling elements interposed between the outer member and the inner member, and a retainer for retaining the balls, wherein the outer member is detachable from an assembly part consisting of the inner member, the balls, and the retainer. a radial distance M from the groove bottom of the raceway groove of the inner member to a counterbore portion of the inner member is 0.2 to 0.7% of a pitch circle diameter of the ball, an axial dimension Z of a counterbore portion of the inner member being 8 to 20% of a diameter Dw of the ball; the inner member has a first step on its outer circumferential surface, the first step being adjacent to the counterbore portion of the inner member and having a smaller diameter than the counterbore portion of the inner member; The angular contact ball bearing has a height X of the first step that is 0.1 to 0.5% of the pitch circle diameter of the ball.

2. 2. The angular contact ball bearing according to claim 1, wherein the first step is an inclined surface.

3. 3. The angular contact ball bearing according to claim 1, wherein the outer member has, on its inner peripheral surface, a second step adjacent to the raceway groove of the outer member and having a larger diameter than the raceway groove of the outer member, The angular contact ball bearing has a height Y of the second step that is 0.1 to 0.5% of the pitch circle diameter of the ball.

4. 4. The angular contact ball bearing according to claim 3, wherein said outer member has a straight portion in a portion of said raceway groove of said outer member adjacent to said second step.

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