JP2007162722A - Crankshaft supporting structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly reliable crankshaft supporting structure by using a needle roller bearing having a cage for suppressing deviation of a divided part in the axial direction. <P>SOLUTION: The crankshaft supporting structure is equipped with a crankshaft and a needle bearing for supporting the crankshaft. The needle roller bearing is equipped with: an outer ring having a plurality of outer ring members divided by a parting line extending in the axial direction of the bearing; a plurality of needle rollers 13 arranged so as to roll freely on a raceway surface of the outer ring; projections 14a on one side of a cut part Q provided at a plurality of locations and recesses 14b for receiving the projections 14a on the other side, on the circumference. An axial direction gap δ between the projection 14a and the recess 14b is set to within a range of 0≤δ≤0.2 mm. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a support structure for a crankshaft used in an engine of an automobile or the like.

  As shown in FIG. 5, the crankshaft 1 includes a shaft portion 2, a crank arm 3, and a crank pin 4 for disposing a connecting rod between adjacent crank arms 3. The shaft portion 2 is rotatably supported by a sliding bearing 20 as shown in FIG.

  Further, instead of the sliding bearing 20 as a bearing for supporting the shaft portion 2, for example, as shown in FIG. 7, the outer ring 6, the needle rollers 7 arranged along the inner diameter surface of the outer ring 6, and the adjacent needle shape It is conceivable to use a needle roller bearing 5 provided with a cage 8 that holds the interval between the rollers 7.

  Such a needle roller bearing 5 has an advantage that a high load capacity and high rigidity can be obtained for a small bearing projection area because the needle roller 7 and the raceway surface are in line contact with each other. Widely used in various fields such as engines. Further, the needle roller bearing 5 has a lower load capacity than the sliding bearing, but has a low frictional resistance during rotation, so that it is possible to reduce the rotational torque and the amount of oil supplied to the support portion.

  However, as shown in FIG. 6, the crank arm 3 is arrange | positioned at the both ends of the axial part 2, and the needle roller bearing 5 cannot be inserted in an axial direction. Therefore, a bearing that can be used in such a place is described in, for example, US Pat. No. 1,192,488 (Patent Document 1).

The needle roller bearing described in the publication has outer ring members 9a and 9b obtained by dividing an outer ring 9 by a dividing line 9c extending in the axial direction of the bearing, as shown in FIG. 8, and FIGS. ) And a cage 10 in which two semicircular split cages are combined.
US Patent No. 1921488

  The cage 10 as shown in FIG. 9 may cause a shift in the axial direction at a divided portion of the cage 10 when the bearing rotates. As a result, an eccentric load is applied to the outer ring 9 and the crankshaft 1, and there is a risk that problems such as peeling and flaking will occur early.

  Accordingly, an object of the present invention is to provide a highly reliable crankshaft support structure by using a needle roller bearing having a cage that suppresses the shift of the divided portion in the axial direction.

  The crankshaft support structure according to the present invention includes a crankshaft and a needle roller bearing that rotatably supports the crankshaft. Paying attention to the needle roller bearing, an outer ring having a plurality of outer ring members divided by a dividing line extending in the axial direction of the bearing, a plurality of needle rollers arranged to roll on the raceway surface of the outer ring, and a circle A plurality of cages having a cutting portion extending in the axial direction on the circumference, the cage having a convex portion on one side of the cutting portion and a concave portion for receiving the convex portion on the other side, the convex portion and the concave portion The axial gap δ is 0 ≦ δ ≦ 0.2 mm. The cage is preferably formed of a resin material.

  As in the above configuration, by setting the axial clearance δ of the fitting portion between the convex portion and the concave portion of the cage within the range of 0 ≦ δ ≦ 0.2 mm, the deviation at the cut portion of the cage is suppressed. be able to. As a result, troubles such as peeling and flaking can be prevented, and a long-life and highly reliable crankshaft support structure can be obtained. The cage is preferably formed of a resin material from the viewpoint of processability.

  Preferably, the crankshaft is used for a multi-cylinder engine. A crankshaft used for a multi-cylinder engine has a shaft portion sandwiched between crank arms at both ends, which increases in proportion to the number of cylinders. A higher effect can be expected by using the needle roller bearing configured as described above for such a crankshaft.

  The present invention provides a long-life and highly reliable crankshaft by suppressing axial displacement of the cage by setting the axial gap between the convex portion and concave portion of the cage cutting portion within a predetermined range. A support structure can be obtained.

  A crankshaft support structure according to an embodiment of the present invention will be described with reference to FIGS.

  The crankshaft support structure shown in FIG. 2 is disposed between the crankshaft 15, the cylinder block 16a, the bearing cap 16b, and the crankshaft 15 and the bearing cap 16b, and has a needle shape that supports the crankshaft 15 rotatably. A roller bearing 11;

  The needle roller bearing 11 includes an outer ring having a plurality of outer ring members 12 divided by a dividing line extending in the axial direction of the bearing, a plurality of needle rollers 13 arranged to be freely rollable on the raceway surface of the outer ring, And a cage 14 having a pocket for accommodating the needle rollers 13.

  The outer ring member 12 is obtained by forming a cylinder as shown in FIG. 3 (a) by cutting and dividing it at two locations in the circumferential direction as shown in FIG. 3 (b). At this time, since the end face of the divided portion is not subjected to grinding or the like, the unevenness when cracked remains as shown in FIG. When the bearing is used, a cylindrical outer ring is obtained by abutting the corresponding end faces. Such a manufacturing method is called “natural split”.

  The cage 14 is formed of a resin material, and is a split type cage having cutting portions Q extending in the axial direction at a plurality of locations on the circumference as shown in FIG. The retainer 14 has a convex portion 14a on one side of the cutting portion Q and a concave portion 14b that receives the convex portion 14a on the other side, and the convex portion 14a and the concave portion 14b are fitted and fixed when assembled. . And as shown in FIG.1 (b), the axial direction clearance | interval (delta) of the convex part 14a and the recessed part 14b is set in the range of 0 <= delta <= 0.2mm.

  By setting it as the said structure, the shift | offset | difference to the axial direction in the cutting part Q of the holder | retainer 14 can be suppressed to the minimum. Thereby, troubles such as peeling and flaking of the outer ring 12 and the crankshaft 15 can be prevented, and a long-life and highly reliable crankshaft support structure can be obtained.

  Here, the axial gap δ between the convex portion 14a and the concave portion 14b is ideally δ = 0 mm, but it is very difficult to realize this accuracy from the viewpoint of manufacturing errors and the like. However, as long as it is within the range of δ ≦ 0.2 mm, the uneven load applied to the outer ring 12 and the crankshaft 15 is small, which is sufficient to suppress the occurrence of trouble due to the displacement of the cage 14.

  Next, a method for incorporating the needle roller bearing 11 having the above-described configuration into the crankshaft 15 will be described.

  First, a cage 14 in which the needle rollers 13 are assembled in advance in each pocket is prepared, and the cage 14 is attached to the crankshaft 15. By fitting the convex portions 14 a and the concave portions 14 b of the divided portion of the cage 14, the cage 14 does not fall off from the crankshaft 15. Next, the outer ring member 12 on one side is assembled in the cylinder block 16a, the crankshaft 15 to which the cage 14 is attached is placed thereon, and the outer ring member 12 on the other side is placed. Finally, the bearing cap 16b is assembled and fixed. By adopting the above assembling procedure, it is possible to assemble the shaft part sandwiched between the crank arms at both ends.

  As a result, as shown in FIGS. 4A and 4B, the inner diameter surfaces of the crankshaft 15, the cage 14, the outer ring member 12, the cylinder block 16a and the bearing cap 16b are arranged concentrically, Stable rotation of the needle roller 13 can be ensured. By adopting the above assembling procedure, it is possible to assemble the shaft part sandwiched between the crank arms at both ends.

  At this time, the cage 14 may be a metal cage produced by pressing or cutting a metal material, but a resin cage produced by injection molding a resin material having a high elastic deformation capability. By doing so, the required accuracy can be easily realized, and the assembling work is further facilitated.

  Moreover, although the outer ring showed the example which consists of the two outer ring members 12, it does not restrict to this, You may combine three or more outer ring members 12. FIG.

  Furthermore, the crankshaft support structure according to the present invention can be applied to the crankshafts of all engines such as automobiles and motorcycles. Further, the number of cylinders of the engine may be single cylinder or multi-cylinder, but it is used for a multi-cylinder engine having a shaft portion whose both ends are sandwiched by crank arms as shown in P portion of FIG. By applying to a crankshaft, a greater effect can be expected.

  As mentioned above, although embodiment of this invention was described with reference to drawings, this invention is not limited to the thing of embodiment shown in figure. Various modifications and variations can be made to the illustrated embodiment within the same range or equivalent range as the present invention.

  The present invention is advantageously used for an engine crankshaft support structure.

It is a figure which shows the characterizing part of this invention, Comprising: (a) is a front view of the retainer for needle roller bearings, (b) is an enlarged view of the Q section. It is a figure which shows the crankshaft support structure which concerns on one Embodiment of this invention. It is a figure which shows the outer ring member of the needle roller bearing of FIG. 2, Comprising: (a) The front view before a division | segmentation, (b) is a figure which shows the state which divided | segmented (a) in two places, (c) is (b) FIG. It is the state after incorporation of the crankshaft support structure concerning one embodiment of this invention, and (a) is a figure seen from the axial direction, and (b) is a figure seen from the direction perpendicular to the axis. It is a figure which shows a crankshaft. It is an enlarged view of the P section of FIG. It is a figure which shows the needle roller bearing which supports the axial part of the conventional crankshaft. It is a figure which shows the conventional division | segmentation outer ring | wheel. It is a figure which shows the conventional holder | retainer, Comprising: (a) is one side of a division | segmentation holder | retainer, (b) is a figure which shows the butt | matching part of a holder | retainer.

Explanation of symbols

  1,15 Crankshaft, 2 shafts, 3,17 Crank arm, 4 Crankpin, 5,11 Needle roller bearing, 6,9 Outer ring, 9a, 9b, 12 Outer ring member, 9c Dividing line, 7,13 Needle shape Roller, 8, 10, 14 Cage, 14a Convex part, 14b Concave part, 16a Cylinder block, 16b Bearing cap, 20 Sliding bearing.

Claims (3)

A crankshaft,
A crankshaft support structure comprising a needle roller bearing that rotatably supports the crankshaft,
The needle roller bearing includes an outer ring having a plurality of outer ring members divided by a parting line extending in the axial direction of the bearing, a plurality of needle rollers disposed on a raceway surface of the outer ring, and a circular roller. A plurality of cages having a cutting portion extending in the axial direction on the circumference,
The cage has a convex portion on one side of the cutting portion and a concave portion that receives the convex portion on the other side, and an axial gap δ between the convex portion and the concave portion is 0 ≦ δ ≦ 0. Crankshaft support structure that is 2 mm.   The crankshaft support structure according to claim 1, wherein the cage is made of a resin material. The crankshaft support structure according to claim 1 or 2, wherein the crankshaft is used in a multi-cylinder engine.

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