Tapered roller bearing assembly method

Abstract

To provide an assembly method of a conical bearing which can inhibit deformations, such as oval deformation and twisting deformation, which affect rotation performance of the conical bearing and eliminate a need of pursuing strict dimensional tolerance to enable reduction of assembly costs.SOLUTION: A retainer 14 and an inner ring 12 are arranged relative to each other so that a radial axis of the retainer matches with a radial axis of the inner ring and multiple conical rollers 13 contact with a small flange part 15 of the inner ring in a state that the multiple conical rollers are retained by the retainer. At least one of the retainer and the inner ring is pressed along an axial direction parallel to the axis to move the retainer to the side of a large flange part 16 of the inner ring relative to the inner ring and cause the retainer to be deformed to the radial outer side through elastic deformation and plastic deformation. When the conical roller has passed through the small flange part of the inner ring, the retainer deformed to the radial outer side is deformed to the radial inner side to a position, at which the roller is prevented from getting over the small flange part and being removed, by spring back.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a method for assembling a tapered roller bearing. [Background technology]

[0002] Conventionally, tapered roller bearings have been used in various drive devices such as construction machinery as bearings that rotatably support the rotation mechanisms of those devices. As shown in Figure 4, this tapered roller bearing 10 comprises an outer ring 11 having an outer ring raceway surface 11a on its inner peripheral surface, an inner ring 12 having an inner ring raceway surface 12a on its outer peripheral surface, a plurality of tapered rollers 13 provided so as to be able to roll between the outer ring raceway surface 11a and the inner ring raceway surface 12a, and a cage 14 that holds the plurality of tapered rollers 13 at predetermined intervals in the circumferential direction.

[0003] The cage 14 used for the tapered roller bearing 10 is made of resin or metal. The method of assembling a tapered roller bearing 10 using a metal cage 14 is the so-called crimping method. Specifically, as shown in FIG. 5 , first, the tapered rollers 13 are held in the pockets of the cage 14 and assembled into the inner ring 12. Then, with the axial end face of the inner ring 12 on the large rib portion 16 side abutting against the inner ring support surface 30, a crimping jig 20 abutting against the cage 14 is pressed toward the cage 14, thereby crimping the inner ring 12, tapered rollers 13, and cage 14 until a desired pocket gap is created so that the inner ring 12, tapered rollers 13, and cage 14 do not separate (a gap that prevents the rollers from moving over the small rib and moving axially of the inner ring 12 and coming off the inner ring 12, even if they move radially outward until there is no gap left).

[0004] For example, in the tapered roller bearing of Patent Document 1, before assembling the tapered rollers and cage into the inner ring, a tapered expanding punch is inserted into the bottom hole to expand the diameter of the small diameter ring portion, and then only the vicinity of the connection portion with the column portion of the small diameter ring portion is crimped inward using a crimping jig, thereby improving the dimensional and shape accuracy of the cage. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-266063 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the crimping method places a large load on the bearing, which can cause the cage to lose its shape. Furthermore, crimping is costly, and in particular, large presses are required for assembling large bearings, which creates serious cost issues. Furthermore, since the crimping mold must be specially designed for each cage, in the case of small-lot products, the cost of manufacturing the special mold must be borne by the small number of cages, which increases product costs.

[0007] In view of the above problems, there is a method of assembling tapered roller bearings using a non-crimping method that does not use crimping. In this method, an overlap is provided in advance between the small rib portion of the inner ring and the tapered rollers to prevent the cage from falling off. During assembly, the cage is positioned on the outside of the inner ring by springing back, and then attached to the inner ring using the overlap.

[0008] Specifically, as shown in Figure 6, inner ring 12 is tilted relative to cage 14, which already holds tapered rollers 13, and while this is done, inner ring 12 is pushed down and assembled. In this example, axis B of inner ring 12 is tilted at a predetermined angle relative to axis C of cage 14, which is perpendicular to a floor surface such as inner ring support surface 30, and while this is the case, inner ring 12 is pushed down and forced into cage 14. As small rib portions 15 of inner ring 12 come into contact with the rolling surfaces of tapered rollers 13, tapered rollers 13 move outward, and as tapered rollers 13 move, cage 14 deforms outward.

[0009] At this time, cage 14 deforms within the range of elastic deformation, and then returns to its original shape when inner ring 12 is completely pressed in. Then, tapered rollers 13 are held by small flange portions 15 of inner ring 12 by the overlapping allowance secured beforehand, and cage 14 is thereby attached to inner ring 12.

[0010] As described above, if the cage 14 can be deformed within the range of elastic deformation and returned to its original shape, the shape of the cage 14 will not collapse. However, the yield point of the steel plate used for the cage 14 is generally low, and it is not easy to design a cage that has an overlap required to prevent it from falling off after assembly so that its shape does not collapse. Naturally, the dimensional tolerances of the inner ring 12 and the cage 14 must be strictly specified and controlled, which could lead to increased manufacturing costs and management costs. Furthermore, even if the dimensional tolerances are strictly specified and controlled, it is not easy to ensure the overlap required for assembly.

[0011] The present invention has been made in view of the above-mentioned problems, and its object is to provide a method for assembling a tapered roller bearing that suppresses deformations such as oval deformation and torsional deformation of the cage that affect the rotational performance of the tapered roller bearing, and that can reduce assembly costs without pursuing strict dimensional tolerances. [Means for solving the problem]

[0012] The above object of the present invention can be achieved by the following configuration. (1) an outer ring having an outer ring raceway on its inner circumferential surface; an inner ring having an inner ring raceway surface on its outer circumferential surface; a plurality of tapered rollers rollably provided between the outer ring raceway surface and the inner ring raceway surface; a metal cage that holds the plurality of tapered rollers at predetermined intervals in the circumferential direction; Equipped with A method for assembling a tapered roller bearing in which a large rib portion is provided at a large diameter side end of the inner ring and a small rib portion is provided at a small diameter side end of the inner ring, comprising: the cage and the inner ring are disposed relative to each other so that, with the plurality of tapered rollers held in the cage, an axis of the cage in the radial direction and an axis of the inner ring in the radial direction coincide with each other and the plurality of tapered rollers come into contact with a small rib portion of the inner ring; at least one of the cage and the inner ring is pressed along an axial direction parallel to the axis, thereby moving the cage relative to the inner ring toward a large rib portion of the inner ring; As the cage moves, the cage is deformed radially outward by elastic deformation and plastic deformation, When the tapered rollers pass over the small rib portion of the inner ring as the cage moves, the cage, which has been deformed radially outward, is deformed radially inward by springback to a position where the rollers do not get over the small rib portion and come off. How to assemble a tapered roller bearing. (2) A method of assembling a tapered roller bearing according to (1), in which the retainer is deformed radially inward by springback, thereby ensuring the necessary engagement between the tapered rollers and the small rib portion of the inner ring. (3) A method for assembling a tapered roller bearing according to (2), wherein the small diameter side end faces of the tapered rollers contact small rib surfaces in the small rib portion of the inner ring, and the small diameter side end faces of the tapered rollers are held by the small rib surfaces. (4) A method of assembling a tapered roller bearing as described in (1), in which the initial dimensions of the retainer are designed so that the necessary engagement between the tapered rollers and the small rib portion of the inner ring is secured when the plurality of tapered rollers and the retainer are assembled into the inner ring. [Effects of the Invention]

[0013] According to the present invention, it is possible to suppress deformation such as oval deformation and torsional deformation of the cage that affect the rotation performance of the tapered roller bearing. Furthermore, it is possible to prevent the cage from falling off the inner ring and reduce assembly costs without pursuing strict dimensional tolerances. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a cross-sectional view illustrating an outline of a method for assembling a tapered roller bearing according to the present invention. [Figure 2] Figure 2 is a cross-sectional view illustrating the steps in the method of assembling a tapered roller bearing using the non-crimping method according to the present invention, where (a) shows the tapered rollers in contact with the small rib portion of the inner ring, (b) shows the state in which the cage has been deformed outward due to elastic deformation and plastic deformation, and (c) shows the state in which the cage has been deformed inward due to spring back, and the tapered rollers are held in place by the small rib portion through the engagement allowance. [Figure 3] FIG. 3 is a schematic diagram illustrating springback. [Figure 4] FIG. 4 is a cross-sectional view illustrating an example of a tapered roller bearing. [Figure 5] FIG. 5 is a cross-sectional view for explaining a method for assembling a conventional tapered roller bearing, and is a diagram for explaining the path of force transmission during crimping. [Figure 6] FIG. 6 is a cross-sectional view illustrating an outline of a conventional method for assembling a tapered roller bearing using a non-caulking method. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, embodiments of the method for assembling a tapered roller bearing according to the present invention will be described in detail with reference to the drawings.

[0016] First, with reference to FIG. 4, a tapered roller bearing to which the present invention is applied will be described.

[0017] As shown in Figure 4, the tapered roller bearing 10 comprises an outer ring 11 having an outer ring raceway surface 11a on its inner peripheral surface, an inner ring 12 having an inner ring raceway surface 12a on its outer peripheral surface, a plurality of tapered rollers 13 rollably arranged between the outer ring raceway surface 11a and the inner ring raceway surface 12a, and a metal cage 14 that holds the plurality of tapered rollers 13 at predetermined intervals in the circumferential direction.

[0018] The inner ring 12 has a small rib portion 15 provided at the small diameter side end of the inner ring 12 and a large rib portion 16 provided at the large diameter side end of the inner ring 12. The small rib surface 15a of the small rib portion 15 comes into contact with the small diameter side end face 13a of the tapered roller 13. The large rib surface 16a of the large rib portion 16 comes into contact with the large diameter side end face 13b of the tapered roller 13.

[0019] The retainer 14 is formed, for example, by pressing a steel plate, and comprises a small-diameter annular portion 14a, a large-diameter annular portion 14b arranged coaxially with the small-diameter annular portion 14a, and a plurality of pillar portions 14c arranged at predetermined intervals (for example, approximately equal intervals) in the circumferential direction to connect the small-diameter annular portion 14a and the large-diameter annular portion 14b, and pocket portions 14d that hold the tapered rollers 13 in a rollable manner are formed between each of the pillar portions 14c adjacent to each other in the circumferential direction.

[0020] The present invention provides a method for assembling such a tapered roller bearing, and the following describes embodiments thereof.

[0021] An embodiment of a method for assembling a tapered roller bearing according to the present invention will be described with reference to Figure 1. Figure 1 is a cross-sectional view illustrating a method for assembling a cage 14 that holds tapered rollers 13 to an inner ring 12 in a tapered roller bearing that includes a metal cage 14.

[0022] In the assembly method of this embodiment, a plurality of tapered rollers 13 are held in advance in pocket portions 14d of cage 14. With tapered rollers 13 held in cage 14, inner ring 12 is placed inside cage 14 and inner ring 12 is pressed down. At this time, unlike the example in FIG. 6, the radial axis A of cage 14 and the radial axis A of inner ring 12 coincide with each other. In addition, the outer diameter surface of small rib portion 15 of inner ring 12 contacts rolling surfaces 13c of each tapered roller 13 at contact points D.

[0023] As the inner ring 12 is pressed down, the retainer 14 deforms (expands in diameter) so as to expand radially outward. Because the axis A of the retainer 14 and the axis A of the inner ring 12 coincide with each other, deformation of the retainer 14, such as elliptical deformation and torsional deformation, can be suppressed.

[0024] A method for assembling a tapered roller bearing will be described in detail with reference to Figure 2. First, as shown in Figure 2(a), the cage 14 and the inner ring 12 are positioned relative to each other so that the rolling surfaces 13c of the tapered rollers 13 contact the small rib portion 15 of the inner ring 12. In other words, the state in Figure 2(a) corresponds to the state in Figure 1. At this time, the small diameter side annular portion 14a of the cage 14 is located at an initial position P1 in the radial direction.

[0025] Next, as shown in Figure 2(b), at least one of the cage 14 and inner ring 12, in this example the inner ring 12, is pressed downward along the axial direction parallel to the axis. The cage 14 and tapered rollers 13 move relative to the inner ring 12 towards the large rib portion 16 of the inner ring 12.

[0026] The rolling surfaces 13c of the tapered rollers 13 are in contact with the outer diameter surface of the small rib portion 15 of the inner ring 12, inclined outward with respect to the axis A of the cage 14 and the inner ring 12. For this reason, the tapered rollers 13 move radially outward as they move toward the large rib portion 16 of the inner ring 12. As the tapered rollers 13 move, they are pushed by the small rib portion 15, and the cage 14 that holds the tapered rollers 13 also moves while deforming so as to expand radially outward.

[0027] The expansion deformation of the metal cage 14 is initially elastic deformation that can return to its original shape. When the cage 14 expands to a predetermined diameter or larger, the metal material that makes up the cage 14 reaches its yield point, and the expansion deformation of the cage 14 changes from elastic deformation to plastic deformation, causing the cage 14 to expand further radially outward. Due to the expansion deformation, the small-diameter annular portion 14a of the cage 14 moves to the expanded diameter position P2.

[0028] While the cage 14 expands due to plastic deformation, once the plastic deformation has reached a predetermined range, it can deform in a direction returning to its original shape, i.e., deform radially inward (reduced in diameter) due to springback. When the small-diameter annular portion 14a of the cage 14 has moved to the expanded diameter position P2, the cage 14 can undergo such springback.

[0029] Under these circumstances, as shown in Figure 2(c), the rolling surfaces 13c of the tapered rollers 13 pass over the small rib portion 15 of the inner ring 12. As a result, the expanded diameter of the cage 14 returns to its original shape due to spring back, that is, it deforms radially inward (reducing its diameter). As a result, the tapered rollers 13 are housed between the small rib portion 15 and large rib portion 16 of the inner ring 12. At this time, the small diameter side annular portion 14a of the cage 14 moves to fixed position P3. At fixed position P3, even if the rollers 13 try to move toward the outer diameter side, the pocket gap is set so that they cannot move to a position where they can get over the small rib portion 15 and move out of the way.

[0030] Figure 3 is a schematic diagram explaining springback, with the vertical axis representing the load applied to the cage and the horizontal axis representing the deformation (amount of deformation) of the cage. In the initial position of Figure 2(a), the load and deformation in Figure 3 are zero. When changing from the state of Figure 2(a) to the state of Figure 2(b), the load passes through A, which is the boundary between the elastic deformation region and the plastic deformation region in Figure 3, and reaches B in Figure 3, which is the state of Figure 2(b). When changing from the state of Figure 2(b) to the state of Figure 2(c), the load passes through B in Figure 3 and reaches C. The difference between B1, which is the amount of deformation at B in Figure 3, and the amount of deformation at C is springback.

[0031] This ensures the necessary engagement between the tapered rollers 13 and the small rib portion 15 of the inner ring 12, and the tapered rollers 13 are held in the small rib portion 15. Specifically, the small diameter side end faces 13a of the tapered rollers 13 come into contact with the small rib surface 15a of the small rib portion 15, and the small diameter side end faces 13a are held by the small rib surface 15a. As a result, the cage 14 is assembled to the inner ring 12 together with the tapered rollers 13.

[0032] According to the assembly method of this embodiment, the axis A of the retainer 14 and the axis A of the inner ring 12 are aligned, making it possible to suppress deformations of the retainer 14 such as elliptical deformation and torsional deformation, which affect the rotational performance of the tapered roller bearing 10.

[0033] Furthermore, the initial dimensions of the cage 14 are set in advance to values that take into account elastic deformation, plastic deformation, and diameter expansion due to springback, making it possible to avoid the impact of diameter expansion on the performance of the tapered roller bearing 10. By allowing plastic deformation of the cage 14 in advance, an overlap allowance for springback can be generated regardless of the dimensional tolerances of the cage 14 and inner ring 12. This makes it possible to prevent the cage 14 from falling off the inner ring 12 without pursuing strict dimensional tolerances. Furthermore, because no large-scale equipment such as that required for the crimping method is required, assembly costs can be reduced.

[0034] Furthermore, by taking into consideration the shape of the cage 14 and the physical properties of the metal material (Young's modulus, yield point, etc.), it is possible to predict (simulate) the amount of elastic deformation at which the elastic deformation of the cage 14 changes to plastic deformation, and the amount of plastic deformation that can spring back after plastic deformation. By using this prediction to derive the initial dimensions of the cage 14, it is possible to eliminate as much as possible the effects of plastic deformation on the finished tapered roller bearing 10.

[0035] In the above description, the inner ring 12 is pressed down toward the cage 14, which is placed on the floor. However, the inner ring 12 may be placed on the floor and the cage 14 may be pressed down from above. Also, the inner ring 12 and the cage 14 may be assembled so that they are relatively close to each other.

[0036] The present invention is not limited to the above-described embodiments, and can be modified and improved as appropriate. [Explanation of symbols]

[0037] 10 Tapered roller bearings 11 Outer ring 11a Outer ring raceway 12 Inner Circle 12a Inner ring raceway surface 13 Tapered roller 13a Small diameter side end face 13b Large diameter side end face 13c Rolling surface 14 Cage 14a Small diameter side ring part 14b Large diameter annular part 14c Pillar 14d pocket 15 Small tsuba 15a Small tsuba face 16 Otsubabe 16a Large Tsuba Face 20 Crimping jig

Claims

1. an outer ring having an outer ring raceway surface on its inner circumferential surface; an inner ring having an inner ring raceway surface on its outer circumferential surface; a plurality of tapered rollers rollably provided between the outer ring raceway surface and the inner ring raceway surface; a metal cage that holds the plurality of tapered rollers at predetermined intervals in the circumferential direction; Equipped with A method for assembling a tapered roller bearing in which a large rib portion is provided at a large diameter side end of the inner ring and a small rib portion is provided at a small diameter side end of the inner ring, comprising: the cage and the inner ring are disposed relative to each other so that, with the plurality of tapered rollers held in the cage, an axis of the cage in the radial direction and an axis of the inner ring in the radial direction coincide with each other and the plurality of tapered rollers come into contact with a small rib portion of the inner ring; at least one of the cage and the inner ring is pressed along an axial direction parallel to the axis, thereby moving the cage relative to the inner ring toward a large rib portion of the inner ring; As the cage moves, the cage is deformed radially outward by elastic deformation and plastic deformation, As the cage moves, when the tapered rollers pass over the small rib portion of the inner ring, the cage, which has been deformed radially outward by plastic deformation, is deformed radially inward by springback to a position where the rollers do not get over the small rib portion and come off, an initial dimension of the cage is designed so that a necessary engagement allowance is secured between the tapered rollers and a small rib portion of the inner ring when the plurality of tapered rollers and the cage are assembled to the inner ring; How to assemble a tapered roller bearing.

2. an outer ring having an outer ring raceway surface on its inner circumferential surface; an inner ring having an inner ring raceway surface on its outer circumferential surface; a plurality of tapered rollers rollably provided between the outer ring raceway surface and the inner ring raceway surface; a metal cage that holds the plurality of tapered rollers at predetermined intervals in the circumferential direction; Equipped with A method for assembling a tapered roller bearing in which a large rib portion is provided at a large diameter side end of the inner ring and a small rib portion is provided at a small diameter side end of the inner ring, comprising: the cage and the inner ring are disposed relative to each other so that, with the plurality of tapered rollers held in the cage, an axis of the cage in the radial direction and an axis of the inner ring in the radial direction coincide with each other and the plurality of tapered rollers come into contact with a small rib portion of the inner ring; at least one of the cage and the inner ring is pressed along an axial direction parallel to the axis, thereby moving the cage relative to the inner ring toward a large rib portion of the inner ring; As the cage moves, the cage is deformed radially outward by elastic deformation and plastic deformation, As the cage moves, when the tapered rollers pass over the small rib portion of the inner ring, the cage, which has been deformed radially outward by plastic deformation, is deformed radially inward by springback to a position where the rollers do not get over the small rib portion and come off, A method for assembling a tapered roller bearing, wherein the cage is deformed radially inward by spring back, thereby ensuring the necessary engagement allowance between the tapered rollers and the small rib portion of the inner ring.

3. 3. A method for assembling a tapered roller bearing according to claim 2, wherein the small diameter side end faces of the tapered rollers contact small rib surfaces of the small rib portion of the inner ring, and the small diameter side end faces of the tapered rollers are held by the small rib surfaces.

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