JP2008095723A - Rolling bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rolling bearing capable of suppressing noise, flaking or the like while having a separable outer ring. <P>SOLUTION: A maximum protrusion quantity Δ of a roller 3c is set smaller than a clearance λ between a retainer 3d and an end portion of a lower half part 3a2. According to such a relation, the roller 3c is laid in a noncontact state to an inner circumferential surface (recessed part 3d5) of the outer ring 3a, at the position of a split plate P of the outer ring 3a, by being restricted by the retainer 3d. Therefore, even if the split plane P of the outer ring 3a is stepped, collision of the roller to the stepped part can be prevented to effectively suppress noise of the roller. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a rolling bearing that can be incorporated in, for example, a connecting rod or a crankshaft of an internal combustion engine.

  Generally, when a crankshaft is rotatably supported with respect to a cylinder block of an internal combustion engine of a vehicle, the journal is supported by a slide bearing. Also, when the connecting rod is rotatably supported with respect to the pin of the crankshaft, the large end portion is supported by a sliding bearing. Here, the sliding bearing can support a relatively large load, but in order to suppress wear, it is necessary to pump an appropriate amount of lubricant from the outside, and there is a problem that the drag torque is large. In recent years, improvement in fuel efficiency of vehicles has become an important issue, and therefore there is a demand for improvement in fuel efficiency by replacing sliding bearings with rolling bearings.

However, one problem in incorporating a rolling bearing into a connecting rod or crankshaft is that the outer ring of the rolling bearing must be divided. However, there is a problem that when the outer ring whose inner circumference is a perfect circle is cut by machining, there is a cutting margin, and therefore the inner circumference does not become a perfect circle when the cut outer rings are combined. Therefore, in the split bearing disclosed in Patent Document 1, the inner ring is true when the cut outer ring is combined by applying stress to the outer ring having a perfect circle on the inner ring to break it and not providing a cutting allowance. I try to get closer to the circle.
JP-A-6-81846

  However, even when fractured outer rings are combined, deviations in the inner circumference in micron units, that is, steps cannot be avoided, and when the housing to which the outer ring is mounted is a split type, the combination caused by component errors Steps on the split surface of the outer ring also increase due to time shifts, and the roller rolling on the inner periphery of the outer ring may generate noise when it gets over the step, or it may cause problems such as flaking starting from the step There is. In particular, in the case of a split housing, when the deviation at the time of combination exceeds the radial clearance of the rolling bearing, the distance between the outer ring and the inner ring becomes smaller than the roller diameter, the roller is restrained, and the rotation failure of the roller There is also a risk of causing it.

  In order to avoid such problems, by making the inner diameter of the outer ring at the split part larger than the inner diameter of the other outer ring, a large clearance between the roller and the inner peripheral surface of the outer ring at the split part of the outer ring is secured, and the load on the roller is reduced. There is an attempt to suppress. However, according to such an attempt, by reducing the plate thickness of the split part of the outer ring, it is possible to suppress the load on the rollers in the vicinity of the split surface, thereby effectively suppressing the occurrence of roller flaking caused by the step collision. However, it has been found that there is a risk of roller noise depending on the conditions. More specifically, if a step occurs on the split surface due to misalignment when combined, even if there is no load before the step, if the roller hits this step, the passing sound of the roller may increase. is there. Especially in applications where quietness is required, it is difficult to use a bearing that may cause noise due to such vibration.

  In view of the problems of the prior art, the present invention aims to provide a rolling bearing capable of suppressing noise, flaking, etc. while having a splittable outer ring.

The rolling bearing of the present invention is a rolling bearing having an inner ring, an outer ring, a rolling element that rolls between both wheels, and a cage that holds the rolling element.
The cage is adapted to limit radial displacement of the rolling element;
The outer ring can be divided in the radial direction, and the rolling element is in a non-contact state with respect to the inner peripheral surface of the outer ring by being restricted by the retainer at the division position of the outer ring. It is characterized by.

  According to the present invention, at the split position of the outer ring, the rolling element is in a non-contact state with respect to the inner peripheral surface of the outer ring by being restricted by the retainer. Even when there is a step in the roller, it is possible to avoid contact with the step, so that the roller noise can be effectively suppressed.

  Further, when the outer ring is put together, a concave portion is formed at the division position, and the concave portion is smoothly connected to the inner peripheral surface of the outer ring, so that when the roller lands on the inner peripheral surface of the outer ring, Shock and noise can be reduced.

  Furthermore, it is preferable that at least one of the rolling element or the cage is subjected to a surface treatment excellent in wear resistance or seizure resistance because friction of the rolling element or the cage can be suppressed.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a front view of a connecting rod of an internal combustion engine in which a bearing according to the present embodiment is incorporated. FIG. 2 is a view of the configuration of FIG. 1 taken along the line II-II and viewed in the direction of the arrow. In FIG. 1, the cage is not shown.

  The connecting rod 1 according to the present embodiment includes a main body 2 formed by forging using a predetermined metal material as a raw material, and a bearing 3 assembled to an inner diameter portion (large end bearing portion) of the large end portion 2b of the main body 2. It is configured. The bearing 3 includes an outer ring 3a, an inner ring 3b (illustrated by a one-dot chain line) that is a pin portion of the crankshaft C (see FIG. 2), a plurality of rollers 3c that are rolling elements that roll between the two wheels, and rollers 3c. It is comprised from the holder | retainer 3d to hold | maintain. In the present embodiment, as will be described later, the outer ring 3a of the bearing 3 can be divided in the radial direction, and the cage 3d can also be divided in the radial direction.

  The main body 2 of the connecting rod 1 has a small end 2a, a large end 2b, and a connecting portion 2c that connects the small end 2a and the large end 2b. Further, a cap 2c having a semi-cylindrical inner circumference with the same inner diameter is assembled to the large end 2b having a semi-cylindrical inner circumference so as to form a cylinder facing each other, and the bearing 3 is sandwiched between them. And are fixed by bolts 8 and 8. In such an internal combustion engine, such a connecting rod 1 has a large end 2b side assembled to a crankshaft C, and a small end 2a side assembled to a piston via a piston pin (not shown) to crank the force from the piston. It has a function of transmitting to the shaft C. At this time, the roller 3c rolls between the outer ring 3a and the inner ring 3b to allow relative rotation between the connecting rod 1 and the crankshaft C with low friction.

  FIG. 3 is a perspective view showing the cage 3d of the bearing 3 according to the present embodiment in an exploded state. As shown in the drawing, the cage 3d is formed by combining the upper half UH and the lower half LH having the same shape so as to face each other. The upper half UH and the lower half LH each have a configuration in which a pair of semi-annular portions 3d1 are connected by a plurality of column portions 3d2 extending in the axial direction, and the end surfaces are M-shaped. A space between the adjacent pillar portions 3d2 is a pocket for holding the rollers 3c (FIGS. 1 and 2). The dividing line between the upper half UH and the lower half LH passes through the centers of the column portions 3d2 at both ends.

  FIG. 4 is a diagram showing the roller 3c of the bearing 3 and the cage 3d combined and cut in the direction perpendicular to the axis at the center position in the axial direction. In FIG. 4, even when the roller 3c moves downward due to its own weight, the circumferential edge portion of the guide portion 3d4 abuts on the outer peripheral surface of the roller 3c, thereby preventing further movement, thereby preventing the roller 3c from coming off. I'm trying to stop. That is, the cage 3d limits the radial displacement of the roller 3c. In a state where the roller 3c is displaced in the maximum radial direction, the protrusion amount from the position of the maximum outer diameter of the cage 3d (here, the outer peripheral surface of the guide portion 3d4) is Δ.

  5A is a view of the outer ring 3a of the bearing 3 as viewed in the axial direction, and FIG. 5B is an enlarged view of the portion indicated by the arrow B of the outer ring 3a in FIG. 5A. is there. As shown in FIG. 5B, the outer ring 3a has a shape that can be divided into two parts in the vertical direction, and is composed of a semi-cylindrical upper half 3a1 and lower half 3a2. Both end portions in the circumferential direction of the upper half portion 3a1 and the lower half portion 3a2 are tapered surfaces 3a3 and 3a4 formed so as to surround the inner peripheral surface. That is, the plate thickness t2 of the end portion has a relationship of t1> t2 with respect to the plate thickness t1 of the central portion of the upper half portion 3a1 and the lower half portion 3a2. By abutting the upper half portion 3a1 and the lower half portion 3a2, the inner circumferential surface of the outer ring 3a is formed with two concave portions 3a5 on both sides with the dividing surface P as the center. The recess 3a5 has a single arc shape when viewed in the axial direction.

  Next, the effects of the present embodiment will be described in comparison with the comparative example. FIG. 6 is a view of the bearing 3 ′ of the comparative example viewed in the axial direction, but the cage is omitted. The bearing of Comparative Example 3 ′ is machined so that the inner diameter of the outer ring 3a is D in a state where the inner ring surface of the outer ring 3a ′ is a cylinder, and the inner ring surface of the split surface P is recessed. Is not formed.

  However, when a bearing capable of dividing the outer ring is assembled between the large end 2b of the connecting rod 1 and the cap 2d as shown in FIGS. Here, in the bearing shown in FIG. 6, it is assumed that a horizontal deviation δ (exaggeratedly illustrated) occurs on the split surface of the outer ring.

  However, if the deviation δ exceeds the bearing clearance, in the bearing 3 ′ of the comparative example shown in FIG. 6, the bearing clearance becomes negative at the position of the split surface P of the outer ring 3a ′, and the roller 3c is restrained here, resulting in poor rotation. May occur. Further, the rollers 3c rolling on the inner peripheral surface of the outer ring 3a 'may come into contact with the stepped portion caused by the deviation of the dividing surface P to generate noise or flake from there.

  On the other hand, in the present embodiment, as shown in FIG. 5, tapered surfaces 3a3 and 3a4 are formed at both ends in the circumferential direction of the upper half 3a1 and the lower half 3a2 so as to surround the inner circumferential surface. Forming. Therefore, even if the deviation δ of the split surface P of the outer ring 3a exceeds the bearing clearance, the recess 3d5 is formed at the position of the split surface P of the outer ring 3a, so that the rollers 3c are not restrained and rotate. There is little risk of defects, and flaking can be suppressed.

  By the way, even when the recess 3d5 is formed, it has been found that if the protrusion amount of the roller 3c from the cage 3d is relatively large, noise is generated when a deviation δ is generated on the split surface P of the outer ring 3a. This will be described.

  In the example shown in FIG. 7A, the maximum protrusion amount Δ (see FIG. 4) of the roller 3c is larger than the clearance λ between the retainer 3d and the end of the lower half 3a2. Therefore, when the roller 3c that rolls on the inner peripheral surface of the outer ring 3a gets over the step between the upper half 3a1 and the lower half 3a2 formed on the split surface P, there is a risk that the roller 3c will come into contact with it and generate noise. .

  On the other hand, in the example shown in FIG. 7B, the maximum protrusion amount Δ of the roller 3c is smaller than the clearance λ between the cage 3d and the end of the lower half 3a2. As is apparent from this relationship, the roller 3c is restricted by the retainer 3d, so that the roller 3c is in a non-contact state with respect to the inner peripheral surface (recess 3d5) of the outer ring 3a at the position of the split surface P of the outer ring 3a. . Therefore, even when there is a step on the split surface P of the outer ring 3a, the roller 3c is prevented from coming into contact with the step, so that the noise of the roller can be effectively suppressed.

  FIG. 8 is an enlarged view similar to FIG. 5B according to a modification of the present embodiment. In the modification of FIG. 8, with respect to the embodiment shown in FIG. 5, the tapered surfaces 3a3 and 3a4 having the radius of curvature R1 formed at the ends of the upper half 3a1 and the lower half 3a2, and the outer ring 3a The difference is that the inner peripheral surface is smoothly connected by curved surfaces 3a6 and 3a7 having a radius of curvature R2. As described above, when the tapered surfaces 3a3, 3a4 and the inner peripheral surface of the outer ring 3a are smoothly connected, the roller 3c once separated from the inner peripheral surface of the outer ring 3a near the dividing surface P in the recess 3a5 is landed again. At this time, since the rise of the surface pressure on the rolling surface becomes gentle, abnormal wear and noise can be reduced.

  FIG. 9 is an enlarged view similar to FIG. 5B according to another modification of the present embodiment. In the modification of FIG. 9, the tapered surfaces 3a3 and 3a4 formed at the ends of the upper half 3a1 and the lower half 3a2 are inwardly convex with a radius of curvature R3 as compared with the embodiment shown in FIG. It is different in that it is smoothly connected to the inner peripheral surface of the outer ring 3a. As described above, when the tapered surfaces 3a3, 3a4 and the inner peripheral surface of the outer ring 3a are smoothly connected, when the roller 3c separated from the inner peripheral surface of the outer ring 3a is landed again by the recess 3a5, its rolling surface Since the surface pressure rises at a low level, abnormal wear and noise can be reduced. The surface of the recess 3a5 does not continue smoothly on the dividing surface P. However, since the roller 3c does not roll on the surface in the vicinity of the dividing surface P, no particular problem occurs.

  In the above embodiment, the roller 3c is prevented from coming into contact with the outer ring 3a by the retainer 3d when passing through the dividing surface P, so that the roller 3c is stretched by centrifugal force. The frictional force of 3d is greater in the vicinity of the split surface P than in the other portions, and if the rotational speed is high, wear caused by contact between the rollers 3c and the cage 3d may increase. . Therefore, in order to reduce friction, it is preferable to perform surface treatment with excellent wear resistance and seizure resistance on at least one of the roller 3c or the cage 3d. Due to the effect of the surface treatment, it is possible to maintain the wear resistance and seizure resistance of the bearing 3 even during high rotation. Examples of such surface treatment include, but are not limited to, a manganese phosphate coating.

  The present invention has been described above with reference to the embodiments. However, the present invention is not limited to the above-described embodiments, and can of course be changed or improved within the scope of the invention. For example, the present invention is not limited to the connecting rod but can be applied to a bearing that supports the journal portion of the crankshaft. In particular, in the journal part of the crankshaft, bearings may be sandwiched between different materials such as aluminum and cast iron.In such a case, the split surface is likely to be displaced due to temperature changes due to the difference in the linear expansion coefficient of the materials. The effect of the invention can be expected more.

It is a front view of the connecting rod of the internal combustion engine in which the bearing concerning this Embodiment was integrated. It is the figure which cut | disconnected the structure of FIG. 1 by the II-II line | wire, and looked at the arrow direction. It is a perspective view shown in the state which decomposed | disassembled the retainer 3d of the bearing 3 concerning this Embodiment. It is a figure cut and shown in the direction of an axis line at the position of lower guide part 3d4 in the state where roller 3c of bearing 3 and cage 3d were combined. 5A is a view of the outer ring 3a of the bearing 3 as viewed in the axial direction, and FIG. 5B is an enlarged view of the portion indicated by the arrow B of the outer ring 3a in FIG. 5A. is there. It is the figure which looked at the bearing 3 'of the comparative example in the axial direction. It is the figure which looked at the roller 3c concerning this Embodiment, and the holder | retainer 3d in the axial direction. It is an enlarged view similar to FIG.5 (b) concerning the modification of this Embodiment. It is an enlarged view similar to FIG.5 (b) concerning another modification of this Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Connecting rod 2 Main body 2a Small end part 2b Large end part 2c Cap 2c Connection part 3 Bearing 3a Outer ring 3b Inner ring 3c Roller 3d Cage 8 Bolt C Crankshaft P Dividing surface

Claims (3)

In a rolling bearing having an inner ring, an outer ring, a rolling element that rolls between both wheels, and a cage that holds the rolling element,
The cage is adapted to limit radial displacement of the rolling element;
The outer ring can be divided in the radial direction, and the rolling element is in a non-contact state with respect to the inner peripheral surface of the outer ring by being restricted by the cage at the division position of the outer ring. Rolling bearing characterized by   The rolling bearing according to claim 1, wherein when the outer ring is put together, a concave portion is formed at the division position, and the concave portion is smoothly connected to an inner peripheral surface of the outer ring.   The rolling bearing according to claim 1 or 2, wherein a surface treatment excellent in wear resistance or seizure resistance is applied to at least one of the rolling element or the cage.

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