JPH06109025A - Split type bearing - Google Patents

Abstract

PURPOSE:To permit the sure engagement of divided surfaces which is applied for a servobearing for supporting the crankshaft of an internal combustion engine to a crankcase and prevent fretting. CONSTITUTION:A bearing outer race 1 is half divided in the circumferential direction by a dividing surface (a) set along the axial direction. An annular groove 3 ranging over the outer race divided bodies 1A and 1B on both the sides of the dividing surface (a) and a groove 4 in the circumferential direction which extends in the circumferential direction of the outside diameter surface are formed on the outside diameter surface of the bearing outer race 1. An engagement ring 5 is fitted in the annular groove, and a thermal expansion correcting band 6 made of synthetic resin is fitted with the groove 4 in the circumferential direction. The engagement ring 5 and the thermal expansion correcting band 6 are formed to an integrally joined thermal expansion correcting band 2 made of synthetic resin or a separated part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a split bearing used as a crank support bearing in an integrated crankshaft of an internal combustion engine.

[0002]

2. Description of the Related Art In an outboard motor engine or the like, a split bearing is used as a support bearing for a crankshaft because of its structure. FIG. 5 shows an example of its use. The crankshaft 10 is an integral type that connects a plurality of connecting rods 11, and is rotatably supported by bearings 13 of a crankcase 12 by split bearings 14 at a plurality of locations. The split type bearing 14 is composed of a roller bearing having an inner ring omitted, and a bearing outer ring 15 is circumferentially divided into two by a split surface along the axial direction. Cage 17 holding rolling element 16
Is similarly divided into two. A retaining ring groove 20 is formed on the outer diameter surface of the bearing outer ring 15, and a snap ring 18 for temporary holding during assembly is fitted therein. Normally, the split portion of the bearing outer ring 15 is a natural split that does not require a cutting allowance and is less likely to be displaced.

The bearing base 13 of the crankcase 12 includes a bearing base body 13a and a cover member 13 bolted to the bearing base body 13a.
b, the bearing outer ring 15 is fitted to the cylindrical inner diameter surface formed between the two 13a, 13b, and the covering member 13b
It is fixed in the pressed state by. In the split type bearing 14 of the example shown in the figure, the bearing outer ring 15 is wide and extends to one side of the rolling element 16, and a ring-shaped seal 19 is interposed between the extended portion and the crankshaft 10. There is. Seal 1
For 9, a contact seal made of rubber or the like and various other types are used.

At the time of assembly, a split bearing 14 is set on the crankshaft 10, and a snap ring 18 is fitted around the crankshaft 10 and temporarily held. That is, until the bearing outer ring 15 is assembled in the crankcase 12, the two divided bodies of the bearing outer ring 15 are stopped so as not to separate.

[0005]

In the internal combustion engine using the split bearing 14 as described above, a. Positive engagement of the split surfaces, b. There are two potential problems with the elimination of fretting. a. That is, in the split bearing 14, it is extremely important to accurately match and hold the split surface positions of the split bodies of the outer ring 15 in order to obtain an accurate raceway surface. But,
Since the snap ring 18 is fitted on the outer circumference of the bearing 14, it becomes a component having a small cross section and a low rigidity in proportion to the inner diameter, and it is difficult to obtain a sufficient holding force. for that reason,
Before being assembled in the crankcase 12, the bearing outer ring 1
The split surface may be displaced due to the weight of No. 5 or an impact during assembly. If it is assembled until the split surface is displaced, it may cause abnormal noise or shorten the life of the bearing, and therefore reassembly is required. In particular, in the split type bearing 14 provided with the seal 19 as in this example, it is necessary to assemble the split type bearing 14 so that the split surfaces are exactly matched with each other in order to ensure the airtightness. Further, when the expanding force is applied from the inside by the seal 19, it is more difficult to keep the split surfaces in a matched state.

B. The housing in which the split bearing 14 is incorporated is usually of a vertically divided type, such as the bearing base body 13a and the covering member 13b in the example of FIG. A knock pin (not shown) is used to prevent creep of the bearing outer ring 15, but during operation, a gap is created between the housing (bearing base 13) and the bearing outer ring 15 due to the difference in thermal expansion, so fretting occurs at the mating surface. To do. That is, the material of the housing is mostly aluminum alloy, and the coefficient of linear expansion is larger than that of the bearing steel used for the bearing outer ring 15, so that the above-mentioned fitting surface gap is formed. If such a gap is created, the bearing outer ring 15 that is prevented from rotating by a knock pin or the like will vibrate at the same position, and fretting will occur. The problem of fretting can be solved by an interference fit, but an interference fit cannot be performed in the above-described vertically split type housing.

An object of the present invention is to provide a split type bearing capable of both positive engagement of split surfaces and prevention of fretting.

[0008]

A split type bearing of the present invention is a split type bearing used as a support bearing for supporting a crankshaft of an internal combustion engine in a crankcase, and a split surface of the bearing outer ring extending in the axial direction. It is applied to those divided in two in the circumferential direction. In this bearing, an annular groove extending over the outer ring divided bodies on both sides of the split surface and a circumferential groove extending in the circumferential direction of the outer diameter surface are formed on the outer diameter surface of the bearing outer ring. An engagement ring for coupling the two outer ring divided bodies is fitted in the annular groove, and a thermal expansion correction band made of synthetic resin is fitted in the circumferential groove. The engaging ring and the thermal expansion correction band may be made of a synthetic resin material integrated with each other.

[0009]

According to this structure, the two outer ring divided bodies are joined to each other at the two split surfaces by the engaging rings fitted in the annular grooves extending over both sides of the split surface. Therefore, it is possible to surely suppress both the axial deviation and the radial deviation of the outer ring divided body. Further, since the engagement ring is locally provided in this way, it can be a component having high rigidity (spring constant), and the outer ring alignment holding force when integrated is strong. Further, since the engagement ring is used, it can be easily attached and detached as required.

Since a thermal expansion correction band made of synthetic resin is wound around the outer diameter surface of the outer ring, when the temperature rises, the thermal expansion of the band causes the fitting surface of the fitting surface due to the difference in linear expansion coefficient between the housing and the outer ring. The gap is filled. Therefore, fretting of the fitting surface is prevented. When the engagement ring and the thermal expansion correction band are formed as an integral part, the number of parts is reduced and the assembling property is improved.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described with reference to FIGS. This split type bearing is composed of a roller bearing in which the inner ring is omitted, and FIG. 1 (A) shows an outer ring 1 before the division and a coupling / thermal expansion correction band 2. The outer ring 1 is a collarless type whose inner diameter surface is a rolling surface of the roller, and is divided into two in the circumferential direction by two split surfaces a along the axial direction. In each split portion, a circular annular groove 3 is formed on the outer diameter surface of the outer ring 1 so as to straddle the outer ring split bodies 1A and 1B on both sides of the split surface a, and along the circumferential direction of the outer diameter surface 2 The circumferential groove 4 of the book is provided all around.

The coupling / thermal expansion compensation band 2 is formed by the annular grooves 2
2 and the two thermal expansion compensation bands 6 fitted in the respective circumferential grooves 4, and the whole is integrally molded of a synthetic resin material. Bonding and thermal expansion compensation band 2
Is curved to have the same curvature as that of the outer ring 1, and is formed into a ring shape divided at one location in the circumferential direction divided at a location adjacent to the engagement ring 5. FIG. 3 shows a developed shape of the joint / thermal expansion correction band 2. As shown in FIG. 1C, the thickness of the thermal expansion compensation band 6 at room temperature is set to be substantially equal to the depth of the circumferential groove 4 of the outer ring 1, and the outer diameter surface of the outer ring 2 and the band surface are the same cylindrical surface. Try to be. The circumferential grooves 4 and the annular groove 2 may be dovetail-shaped in cross section, and the cross-sectional shapes of the thermal expansion correction band 6 and the engaging ring 5 may be formed in a shape corresponding to the groove cross section. Further, a ring-shaped core metal (not shown) may be inserted in the engaging ring 5 portion of the coupling / thermal expansion correction band 2.

The procedure for manufacturing the outer ring 1 will be described. When the outer ring 1 is turned, the annular groove 3 is machined at the planned splitting site and the circumferential groove 4 is machined on the outer periphery. The turned product is subjected to processes such as heat treatment and polishing. Finally, a natural splitting process of the split surface a is performed. In the natural splitting, shallow grooves or the like along the splitting surface a may be provided on the outer diameter surface or the like, or notches may be provided on the end faces on both sides of the outer ring 1 so as to break at a predetermined portion. The joint / thermal expansion correction band 2 is fitted into the annular groove 3 and the circumferential groove 4 of the divided outer ring divided bodies 1A and 1B, and the outer ring divided bodies 1A and 1B are joined together.

Incidentally, on the inner peripheral side of the outer ring 1, a rolling element and a two-split cage for holding the rolling element are arranged as in the example of FIG. The split bearing of this embodiment is installed in the crankcase 12, for example, by being assembled to the crankshaft 10 shown in FIG. 5 instead of the split bearing 14 shown in FIG.

According to the split type bearing having this structure, since the outer ring divided bodies 1A and 1B are coupled by the engaging rings 5 at the two split surfaces a, the outer ring divided bodies 1A and 1B are displaced in the axial direction. , And the radial deviation can be surely suppressed. Further, since the engaging ring 5 is locally provided in this way, it can be a highly rigid component and has a strong alignment holding force of the outer ring 1 when integrated. Therefore, a highly accurate raceway surface can be obtained, and the seal 1 as shown in the example of FIG.
Even when 9 is provided, the reliable airtightness can be secured. Further, since the engagement ring 5 is used, it can be easily attached and detached as required.

Since the thermal expansion compensation band 6 made of synthetic resin is wound around the outer diameter surface of the outer ring 1, the outer diameter surface of the band 6 is expanded as shown in FIG. The gap between the fitting surfaces due to the difference in linear expansion coefficient between the housing and the outer ring 1 is filled. Therefore, fretting of the fitting surface is prevented. Further, in this embodiment, two engagement rings 5 are used.
Since each of the thermal expansion correction bands 6 is integrated into the band 2, the number of parts is small and the assemblability is good.

Although the engaging ring 5 and the thermal expansion correction band 6 are integrated in the above embodiment, they may be separate parts. In that case, the engagement ring 5 has, for example, FIG.
A circular circlip, a disc spring, a chrysanthemum washer or the like shown in (C) can be used, or a coil spring or the like can be used. As the material of the engaging ring 5, iron, aluminum, resin, wire, press material, spring steel, or the like is used. Further, although the annular groove 3 is annular in the above embodiment, it may be rectangular or oval annular groove. Further, although the embodiment has been described with reference to the case of the collarless outer ring 1, the present invention can be applied to the case of the collared outer ring. Further, although the above embodiment has been described with respect to the case where the inner ring is omitted, the present invention can be applied to a bearing with an inner ring.

[0018]

According to the split type bearing of the present invention, an annular groove is formed on the outer diameter surface of the bearing outer ring so as to straddle the outer ring divided bodies on both sides of the split surface, and the engaging ring is fitted in the annular groove. Therefore, the split surfaces can be matched with each other with a sufficient holding force to surely prevent the shift, and can be easily attached and detached as necessary. In addition, because a circumferential groove is provided on the outer peripheral surface of the bearing outer ring and a thermal expansion band made of synthetic resin is wound, the thermal expansion of this band prevents the occurrence of gaps on the mating surfaces due to temperature rise, and fretting Can be prevented. When the engagement ring and the resin band are integrated, the number of parts is reduced and the assembling property is improved.

[Brief description of drawings]

FIG. 1A is a perspective view of an outer ring of a bearing according to an embodiment of the present invention, which is not yet divided, and a joint and thermal expansion correction band, and FIG.
Is a side view of the split portion, and (C) is a sectional view taken along line CC of FIG.

FIG. 2 is a cutaway front view showing a thermal expansion state of a split portion of the bearing.

FIG. 3 is a development view of a joint / thermal expansion correction band.

4A and 4B are cross-sectional views of various examples of engagement rings,
FIG. 7C is a plan view of another example of the engagement ring.

FIG. 5 is a partial cross-sectional view of a crankshaft in which a conventional split bearing is assembled.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Outer ring, 1A, 1B ... Outer ring divided body, 2 ... Coupling and thermal expansion correction band, 3 ... Annular groove, 4 ... Circumferential groove, 5 ... Engagement ring,
6 ... Thermal expansion compensation band, a ... Split surface

Claims (2)

[Claims] 1. A split bearing used as a support bearing for supporting a crankshaft of an internal combustion engine in a crankcase, wherein a bearing outer ring is circumferentially divided into two parts by a split surface extending in the axial direction. On the outer diameter surface of the bearing outer ring, an annular groove that straddles the outer ring divided bodies on both sides of the split surface,
A circumferential groove extending in the circumferential direction of the outer diameter surface is formed, and an engagement ring for coupling the outer ring divided bodies is fitted in the annular groove, and a thermal expansion made of synthetic resin is made in the circumferential groove. Split bearing with a correction band fitted. 2. The split bearing according to claim 1, wherein the engagement ring and the thermal expansion compensation band are made of a synthetic resin material that is integral with each other.