JP2007139153A - Structure of supporting crankshaft - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide structure of supporting a crankshaft which is provided with a needle bearing capable of restraining abnormal noise when a needle roller passes through a stepped portion of a outer ring. <P>SOLUTION: The needle bearing 11 which supports a shaft portion of the crankshaft is provided with an outer ring 12 including a plurality of outer ring members 12a which are divided by parting lines extending in axial direction of the bearing, a plurality of needle rollers 13 which are disposed to make it possible to roll on track surface of the outer ring 12 and a retainer 14 including a pocket which houses the plurality of needle rollers 13. Then, the parting line of two outer ring members 12a is provided on both sides of circumferential direction in position separated from each other at 50&deg; or more based on maximum radial load point of the structure 15 of supporting the crankshaft. <P>COPYRIGHT: (C)2007,JPO&amp;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. 7, 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.

  For example, a sliding bearing (not shown) may be used as the bearing 5 that supports the shaft portion 2. Or a needle roller provided with the outer ring | wheel 6, the needle roller 7 arrange | positioned along the internal-diameter surface of the outer ring | wheel 6, and the holder | retainer 8 holding the space | interval of the adjacent needle roller 7 as shown in FIG. Generally, a bearing 5 is used.

  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, the crank arm 3 is arranged at both ends of the shaft portion 2 as in the P portion of FIG. 7, and the needle roller bearing 5 cannot be inserted in the 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 includes an outer ring member 9a, 9b obtained by dividing the outer ring 9 by a dividing line 9c extending in the axial direction of the bearing as shown in FIG. Not shown).
US Patent No. 1921488

  When the needle roller bearing described in the above publication is incorporated in the shaft portion 2 sandwiched between the crank arms 3 of the crankshaft 1, the cage and the outer ring members 9a and 9b accommodating the needle rollers are respectively viewed from the radial direction. Can be incorporated.

  At this time, it is ideal that the outer ring 9 has a perfect cylindrical shape as shown in FIG. 10A, but actually, as shown in FIG. 10B, the outer ring members 9a and 9b. Is displaced in the radial direction, and a step is formed in the divided portion. Furthermore, this step becomes larger as the mounting accuracy is worse.

  When the needle roller 7 passes through the stepped portion, an abnormal sound is generated. This abnormal noise increases as the level difference increases, and increases as the bearing rotates at a high speed. This is a serious problem for a bearing that supports a high-speed rotating shaft such as the crankshaft 1.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a crankshaft support structure that can suppress abnormal noise when needle rollers pass through a stepped portion of an outer ring.

  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, it comprises an outer ring having a plurality of outer ring members divided by a dividing line extending in the axial direction of the bearing, and a plurality of needle rollers arranged to roll on the raceway surface of the outer ring. The dividing line is provided at a distance of 50 ° or more on both sides in the circumferential direction with reference to the maximum radial load point of the needle roller bearing.

  By arranging the dividing line of the outer ring at a position away from the maximum radial load point as in the above configuration, it is possible to suppress abnormal noise when the needle rollers pass through the stepped portion. As a result, a crankshaft support structure with low noise can be obtained. In the present specification, the “maximum radial load point” refers to a point where the largest radial load is applied on the outer ring circumference of the needle roller bearing incorporated in the crankshaft.

  Preferably, the dividing line is provided at a distance of 50 ° or more on both sides in the circumferential direction with respect to a point symmetrical to the maximum radial load point with the bearing center as the center. Usually, a large radial load is also applied to a point symmetrical to the maximum radial load point around the bearing center. Therefore, a crankshaft support structure with less noise can be obtained by arranging the dividing line of the outer ring at a position away from this point.

  The present invention provides a crankshaft support structure with reduced noise that suppresses abnormal noise when needle rollers pass through the stepped portion by disposing the stepped portion of the outer ring away from the maximum radial load point. Can do.

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

  The crankshaft support structure shown in FIG. 2 includes a crankshaft 15 having a shaft portion 16, crank arms 17 located at both ends of the shaft portion 16, and a crank pin 18 disposed on the opposite side of the shaft portion 16 of the crank arm 17. The needle roller bearing 11 that rotatably supports the crankshaft 15, a crankcase 19, and a crankcase cap 20 are provided.

  As shown in FIG. 1, the needle roller bearing 11 is arranged on an outer ring 12 having a plurality of outer ring members 12 a divided by a dividing line extending in the axial direction of the bearing, and on a raceway surface of the outer ring 12 so as to be rollable. A plurality of needle rollers 13 and a cage 14 having a pocket for accommodating the plurality of needle rollers.

  The outer ring member 12a is obtained by applying an impact to the cylindrical outer ring 12 formed by cutting as shown in FIG. 3A and dividing it into two in the circumferential direction (see FIG. 3B). 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 12 is obtained by abutting the corresponding end faces. Such a manufacturing method is called “natural split”.

  On the other hand, as shown in FIG. 4A, the cage 14 is formed by combining two divided cages 14a that are divided into two in the circumferential direction by the cutting portion 14b. Moreover, as shown in FIG.4 (b), it has the pocket 14c which accommodates the needle roller 13. As shown in FIG.

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

  First, the needle rollers 13 are assembled in each pocket of the cage 14. Next, the outer ring member 12a on one side is incorporated into the crankcase 19, and the split cage 14a on one side, the crankshaft 15, the cage 14a on the other side, and the outer ring member 12a on the other side are placed thereon. Finally, the crankcase cap 20 is assembled and fixed.

  At this time, the dividing line of the two outer ring members 12a is provided at a position separated by 50 ° or more on both sides in the circumferential direction with reference to the maximum radial load point of the crankshaft support structure 15. By setting it as the said structure, even when there is a level | step difference in the abutting part of the outer ring member 12a, the abnormal sound when the needle roller 13 passes a level | step-difference part can be suppressed. As a result, a crankshaft support structure with low noise can be obtained.

  Further, as shown in FIG. 5, since a large load is generally applied to a point symmetrical to the maximum radial load point around the center of the bearing, the dividing line of the outer ring member 12a has a circumferential direction with respect to this point. It is provided at a position separated by 50 ° or more on both sides. That is, it is good to provide within the range of 50 ° -130 ° at both ends of the maximum radial load point.

  Next, in order to confirm the effect of the present invention, a test was performed in which the positional relationship between the maximum radial load point of the crankshaft and the dividing line of the outer ring member 12a was changed and the sound during rotation of the bearing was measured.

  In addition, the crankshaft support structure used for the test has the same maximum radial load point and the dividing line (shown as 0 ° in the table), and 30 °, 50 °, 70 °, 90 ° for both. Degrees of deviation were used. Moreover, the test was implemented at 1000 rpm, 1800 rpm, and 5000 rpm, respectively, as the rotation speed of the bearing. The results are shown in Table 1 and FIG.

  Referring to Table 1 and FIG. 6, when the dividing line of the outer ring member 12a is 50 ° or more away from the maximum radial load point, the sound during rotation is small, and the sound is loud even if the rotation speed is changed. It was confirmed that there was not much change. Furthermore, in this test, it was confirmed that the sound was the smallest when the dividing line and the maximum radial load point were arranged 90 ° apart.

  The cage 14 may be a metal cage manufactured by pressing or cutting a metal material, or may be a resin cage manufactured by injection molding a resin material having a high elastic deformability. Good.

  Moreover, although the outer ring | wheel 12 showed the example which consists of two outer ring members 12a, it was not restricted to this, You may combine three or more outer ring members 12a.

  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 needle roller bearing used for FIG. 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. 1, 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 a figure which shows the holder | retainer of the needle roller bearing of FIG. 1, Comprising: (a) is a front view, (b) is a sectional side view. It is a figure which shows the test result for confirming the effect of this invention. It is a figure which shows distribution of the radial load loaded on the needle roller bearing of FIG. It is a figure which shows the conventional crankshaft. It is a figure which shows the conventional needle roller bearing which supports the axial part of FIG. It is a figure which shows the conventional outer ring | wheel used for the needle roller bearing of FIG. It is a figure which shows a state when the outer ring member of FIG. 9 is combined, Comprising: (a) is an example combined correctly, (b) is an example combined off.

Explanation of symbols

  1,15 Crankshaft, 2,16 Shaft, 3,17 Crankarm, 4,18 Crankpin, 5,11 Needle roller bearing, 6,9,12 Outer ring, 9a, 9b, 12a Outer ring member, 9c Dividing line 7, 13 Needle roller, 8, 14 cage, 14a split cage, 14b cutting part, 14c pocket, 19 crankcase, 20 crankcase cap.

Claims (2)

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 dividing line extending in the axial direction of the bearing, and a plurality of needle rollers arranged to be freely rollable on the raceway surface of the outer ring. ,
The crankshaft support structure, wherein the dividing line is provided at a distance of 50 ° or more on both sides in the circumferential direction with reference to the maximum radial load point of the needle roller bearing.   2. The crankshaft support structure according to claim 1, wherein the dividing line is provided at a distance of 50 ° or more on both sides in a circumferential direction with respect to a point symmetrical to the maximum radial load point with a bearing center as a center.

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