JP2009085235A - Bearing structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provided a bearing structure, which can be simply worked and reduced in its manufacturing cost. <P>SOLUTION: The bearing structure 1 comprises a housing including a first housing portion 13 having a recess of a substantially semicircular section and a second housing portion 14 having a recess of a substantially semicircular section and forming a supporting hole 16 of a substantially circular section together with the recess 13a of the first housing portion 13; and two halved roller bearings 2 having a shaft 12 fitted therein including one set of two halved outer rings 3a, 3b arranged closely in the supporting hole 16 of that housing, a plurality of rolling elements 4 arranged to roll on individual inner sides faces of the two halved outer rings 3a, 3b, and one set of two halved retainers 5a, 5b for retaining the individual rolling elements 4 arranged substantially equidistantly in the circumferential direction. The internal diameter of the supporting hole 16 in the direction of the mating faces of the housing portions is made larger than the internal diameter in the direction displaced by 90 degrees from that of the mating faces. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a bearing structure. More specifically, the present invention relates to a bearing structure including a split-type rolling bearing and a housing that supports the rolling bearing.

  In engines such as automobiles and ships, the bearings that support the crankshaft that converts the reciprocating motion of the pistons into rotational motion are arranged between the counterweights or between the counterweights and the connecting rod large end. A split bearing divided into two is used.

Conventionally, a sliding bearing has been used as the support bearing. However, in recent years, since the demand for an engine with less fuel consumption is increasing, in order to reduce the rotation loss, the sliding bearing is replaced with the supporting bearing. It has been proposed to use rolling bearings divided in the circumferential direction.
This split type rolling bearing includes, for example, a pair of split outer rings, a plurality of rollers arranged so as to be able to roll on each inner surface of both split outer rings, and each roller substantially in the circumferential direction. And a set of two split cages that are held so as to be arranged at equal intervals. The crankshaft is fitted into the rolling bearing as an inner ring member.

  By the way, in the split type rolling bearing, the circumferential end surfaces of the two pairs of split outer rings are in contact with each other to form a mating surface. In this mating surface, the fitting surface of the housing that houses the outer ring Due to the processing state of the above, or due to an assembly error of the outer ring to the housing, a radial shift may occur at both ends of the opposing outer ring. As a result, a step that protrudes radially inward is formed on the mating surface, and vibration and noise are generated when the roller passes through this step, and early damage such as cracking, chipping, and peeling of the roller and outer ring occurs. There is a risk of doing.

Therefore, in order to eliminate the influence of such a step, it has been proposed to perform processing such as forming an inclined surface at the circumferential end of the outer ring (see, for example, Patent Document 1).
Patent Document 1 contains an outer ring having split surface portions combined with each other, a plurality of rollers that roll along the inner peripheral surface of the outer ring, and a cage disposed on the inner peripheral surface of the outer ring. And each split surface portion of the outer ring has a surface inclined with respect to the axial direction, and the inner peripheral surface side of each of the split surface portions is inclined at least in the radial direction and goes to the tip. According to this, it is described that it has an inclined surface with a gradually decreasing thickness. And according to the bearing of patent document 1, generation | occurrence | production of a level | step difference can be prevented with the said inclined surface.

Further, it has been proposed to change the radial dimension of the outer ring depending on the position in the circumferential direction (see, for example, Patent Document 2).
In Patent Document 2, each outer diameter shape of the outer ring divided into two is formed into a semicircle obtained by dividing one perfect circle into two, and each inner diameter shape of the two outer rings divided into one perfect circle. A rolling bearing is described which is formed into a partial circle having a deformed portion in a part of a half circle divided into two, and the center of this partial circle is offset by a predetermined amount with respect to the bearing center.

JP 2006-336765 A JP 2006-258138 A

However, in the bearing described in Patent Document 1, it is necessary to form an inclined surface on the inner peripheral surface side of the split surface portion of the outer ring, and there is a problem that processing is complicated and manufacturing cost is high due to this.
Also, in the bearing described in Patent Document 2, it is necessary to perform uneven thickness processing on the outer ring and to perform hardening processing such as quenching and polishing, which is complicated and causes high manufacturing costs. There is a problem of sticking.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a bearing structure that is easy to process and can reduce manufacturing costs.

The bearing structure of the present invention has a recess having a substantially semicircular cross section in which a first housing part having a recess having a substantially semicircular cross section and a support hole having a substantially circular cross section are formed by the recess of the first housing part. A housing comprising a second housing part;
A pair of split outer rings arranged closely in the support hole of the housing, a plurality of rolling elements arranged to roll on the inner surfaces of the two split outer rings, A bearing structure comprising a pair of split cages for holding the moving body so as to be arranged at substantially equal intervals in the circumferential direction, and comprising a split rolling bearing into which the shaft is fitted,
The support hole is characterized in that the inner diameter in the housing part mating surface direction is larger than the inner diameter in the direction shifted by 90 ° from the mating surface direction.

In the bearing structure of the present invention, the contact surface between the circumferential end portion of the first housing portion and the circumferential end portion of the second housing portion (housing portion mating surface; two locations at equal intervals in the circumferential direction) In the case where the connecting direction is the housing mating surface direction, the inner diameter in the housing portion mating surface direction of the support hole into which the two-rolling bearing is fitted is shifted by 90 ° from the mating surface direction. It is also bigger. That is, the cross-sectional shape of the support hole is not a perfect circle, but the inner diameter in the housing surface mating surface direction is larger. Thereby, a space larger than the diameter of the rolling elements can be formed between the outer peripheral surface of the shaft and the inner peripheral surface of the outer ring in the vicinity of the mating surface. As a result, the rolling element can pass through the vicinity of the mating surface without sliding against the inner peripheral surface of the outer ring near the mating surface. Even if a step is formed at the end of the outer ring on the mating surface, It is possible to prevent vibration and noise from being generated by this step when the moving body passes. It is also possible to prevent early damage such as cracking, chipping and peeling of the rolling elements and the outer ring.
The adjustment of the inner diameters of the recesses of both housing parts can be easily performed by machining, and the manufacturing cost can be reduced.

  By shifting the centers of curvature of the recesses of the first housing part and the second housing part in directions opposite to each other along the direction shifted by 90 ° from the mating surface direction, the inner diameter in the housing unit mating surface direction The inner diameter in a direction shifted by 90 ° from the mating surface direction can be made larger. Thereby, in the vicinity of the mating surface, a space larger than the diameter of the rolling element can be formed between the outer peripheral surface of the shaft and the inner peripheral surface of the outer ring, and the rolling element is formed on the inner peripheral surface of the outer ring near the mating surface. The vicinity of the mating surface can be passed without sliding contact.

  By making the shape of the support hole elliptical, the inner diameter in the housing portion mating surface direction can be made larger than the inner diameter in the direction shifted by 90 ° from the mating surface direction. Also in this case, in the vicinity of the mating surface, a space larger than the diameter of the rolling element can be formed between the outer peripheral surface of the shaft and the inner peripheral surface of the outer ring. It is possible to pass the vicinity of the mating surface without sliding contact with.

  It is preferable that the inner diameter of the housing portion mating surface direction be larger by 0.01 to 1 mm than the inner diameter in a direction shifted by 90 ° from the mating surface direction. Thereby, generation | occurrence | production of the said vibration, noise, and early damage can be prevented, rolling a rolling element smoothly.

  According to the bearing structure of the present invention, the processing is simple and the manufacturing cost can be reduced.

Hereinafter, embodiments of a bearing structure of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a cross-sectional explanatory view of a large end portion of a connecting rod (connecting rod) to which a bearing structure 1 according to an embodiment of the present invention is applied. The connecting rod 10 has a large end portion 11 supported by the crankshaft 12 and a piston (not shown) attached to a small end portion (not shown) via a pin.

  The large end portion 11 has a cap portion 14, which is a second housing portion, having a concave portion having a substantially semicircular cross section, and a bolt 15 on a main body portion 13, which is a first housing portion having a concave portion having a substantially semicircular cross section. In this structure, the support hole 16 having a substantially circular cross section is formed by fastening and fixing. The two-rolling bearing 2 is incorporated in a support hole 16 having a substantially circular cross section formed by the main body portion 13 and the cap portion 14.

  The rolling bearing 2 is arranged so that it can roll on each inner side surface of the two split outer rings 3a, 3b and the two split outer rings 3a, 3b arranged in close contact with each other in the support hole 16. And a pair of split cages 5a and 5b for holding the rollers 4 so as to be arranged at substantially equal intervals in the circumferential direction. An inner ring member of the rolling bearing 2 is configured.

  In the present embodiment, the inner diameter of the support hole 16 in which the rolling bearing 2 is fitted is larger than the inner diameter in the direction shifted by 90 ° from the mating surface direction. That is, in the enlarged explanatory view of the rolling bearing 2 shown in FIG. 2, the dimension represented by D2 (This D2 indicates the outer diameter of the outer rings 3a and 3b, but the outer rings 3a and 3b are arranged on the inner peripheral surface of the housing. Since it is closely arranged, the inner diameter dimension of the support hole 16 is substantially the same as the dimension indicated by D1. As a result, the radial width w of the outer rings 3a and 3b is constant in the circumferential direction, so that the inner diameter d2 of the outer rings 3a and 3b in the housing mating surface direction is shifted by 90 ° from the mating surface direction. It becomes larger than the inner diameter d1 in the direction. In FIG. 2, the cage is not shown for easy understanding.

  By setting D2> D1 (d2> d1), a space larger than the diameter of the roller 4 is formed between the outer peripheral surface of the crankshaft 12 and the inner peripheral surfaces of the outer rings 3a and 3b in the vicinity of the mating surface of the housing. be able to. As a result, the roller 4 can pass near the mating surface without sliding against the inner peripheral surface of the outer ring in the vicinity of the mating surface, and a step is formed at the circumferential end of the outer rings 3a and 3b on the mating surface. Even if it is made, it can prevent that a vibration and a noise generate | occur | produce by this level | step difference at the time of roller passing. In addition, it is possible to prevent early damage such as breakage, chipping, and peeling of the rollers 4 and the outer rings 3a and 3b.

  The main body part 13 and the cap part 14 constituting the housing are made of a material such as aluminum or an aluminum alloy, and the inner diameter of the support hole 16 can be easily adjusted by machining. As a result, the manufacturing cost of the bearing structure can be reduced.

  For example, as shown in FIG. 3, the inner diameter is adjusted by moving a semicircular curvature center O constituting the inner surface of the recess 13a of the main body 13 by 90 ° from the direction of the mating surface (up and down in FIG. 3). The direction can be shifted by a predetermined distance δ along the direction. When a semicircle is drawn around the new center of curvature O ′, the radius in the housing part mating surface direction is larger than the radius in a direction shifted by 90 ° from the mating surface direction. In this case, for the cap portion 14 (not shown), it is necessary to shift the center of curvature of the semicircle constituting the inner surface of the concave portion of the cap portion 14 upward by a predetermined distance δ in FIG. Note that FIG. 3 exaggerates the deviation amount δ of the center of curvature for easy understanding.

  The difference between D2 and D1 can be set to, for example, 0.01 to 1 mm, thereby preventing the occurrence of vibrations and noises due to the above-described steps and early damage while rolling the roller 4 smoothly. can do.

  The adjustment of the inner diameter can also be performed by making the cross-sectional shape of the support hole 16 elliptical. At this time, the major axis of the ellipse is made to coincide with the mating surface direction of the housing, and the minor axis of the ellipse is made to coincide with the direction shifted by 90 ° from the mating surface direction. Also in this case, in the vicinity of the mating surface, a space larger than the diameter of the roller 4 can be formed between the outer peripheral surface of the crankshaft 12 and the inner peripheral surfaces of the outer rings 3a and 3b. The vicinity of the mating surface can be passed without sliding on the inner peripheral surface of the outer ring in the vicinity.

In the embodiment described above, the roller is used as the rolling element, but a bearing using balls may be used. Further, although the bearing structure is applied to the large end portion of the connecting rod, as shown in FIG. 4, the upper block 21 that is a housing constituting a part of the crankshaft fixing portion 20 and the upper block 21 are integrated. It can also be used as a bearing for supporting a crankshaft, which is disposed in a support hole formed by a lower block 22 which is a housing coupled to the shaft. In FIG. 4, reference numeral 23 denotes a fixing bolt that integrally fixes the upper block 21 and the lower block 22, and 24 denotes a support shaft of the crankshaft.
Furthermore, in the above-described embodiment, the crankshaft is exemplified as the shaft fitted into the bearing, but the bearing structure of the present invention can also be applied to other shafts such as a camshaft.

It is a section explanatory view of a connecting rod big end to which a bearing structure concerning one embodiment of the present invention is applied. FIG. 2 is a partially enlarged explanatory view of the bearing structure shown in FIG. 1. It is an expansion explanatory view of the main part which is the 1st housing part. It is a section explanatory view of a crankshaft fixed part of an engine to which a bearing structure concerning one embodiment of the present invention is applied.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Bearing structure 2 Rolling bearing 3a Outer ring 3b Outer ring 4 Roller (rolling element)
5a Cage 5b Cage 6 Mating surface 10 Connecting rod 11 Large end portion 12 Crankshaft 13 Body (first housing portion)
14 Cap part (second housing part)
15 Bolt 16 Support hole

Claims (4)

The first housing part having a concave part with a substantially semicircular cross section and the second housing part having a concave part with a substantially semicircular cross section forming a support hole having a substantially circular cross section with the concave part of the first housing part. A housing;
A pair of split outer rings arranged closely in the support hole of the housing, a plurality of rolling elements arranged to roll on the inner surfaces of the two split outer rings, A bearing structure comprising a pair of split cages for holding the moving body so as to be arranged at substantially equal intervals in the circumferential direction, and comprising a split rolling bearing into which the shaft is fitted,
A bearing structure, wherein an inner diameter of the support hole in a housing part mating surface direction is larger than an inner diameter in a direction shifted by 90 ° from the mating surface direction.   By shifting the centers of curvature of the recesses of the first housing part and the second housing part in directions opposite to each other along a direction shifted by 90 ° from the mating surface direction, the inner diameter in the housing unit mating surface direction The bearing structure according to claim 1, wherein the bearing structure is larger than the inner diameter in a direction shifted by 90 ° from the mating surface direction.   The bearing structure according to claim 1, wherein the shape of the support hole is an ellipse, whereby an inner diameter in the housing part mating surface direction is larger than an inner diameter in a direction shifted by 90 ° from the mating surface direction.   The bearing structure according to any one of claims 1 to 3, wherein an inner diameter in the housing part mating surface direction is larger by 0.01 to 1 mm than an inner diameter in a direction shifted by 90 ° from the mating surface direction.

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