JP5064910B2 - Needle roller bearing and crankshaft support structure - Google Patents

Description

  The present invention relates to a needle roller bearing, and more particularly to a needle roller bearing that rotatably supports a crankshaft.

  Referring to FIG. 9, a conventional crankshaft 101 has a shaft portion 102, a crank arm 103, and a crank pin 104 for arranging a connecting rod between adjacent crank arms 103.

  In addition, a rolling bearing that rotatably supports the shaft portion 102 of the crankshaft 101 having the above-described configuration is described in, for example, Japanese Patent Publication No. 7-506889 (Patent Document 1). The rolling bearing described in the publication includes an outer ring, a plurality of rolling elements disposed along an inner diameter surface of the outer ring, and a cage that holds the plurality of rolling elements.

The rolling bearing configured as described above is completed by incorporating the roller with cage, the outer ring, and the housing in this order into the shaft portion 102. In order to enable the shaft 102 sandwiched between the crank arms 103 to be assembled from the radial direction, the outer ring includes an arc-shaped first portion having a central angle larger than 180 ° and an arc having a central angle smaller than 180 °. A split outer ring including the second portion of the shape is formed.
Japanese translation of PCT publication No. 7-506889

  Here, since the slit size of the first portion is smaller than the maximum outer diameter of the roller with cage, it cannot be incorporated unless it is elastically deformed in the direction of expanding the slit. Further, the amount of elastic deformation of the first portion increases as the central angle of the first portion increases. On the other hand, the elastic deformability decreases as the thickness of the first portion increases. Therefore, the outer ring cannot be easily incorporated depending on the dimensional relationship of the bearing.

  Therefore, an object of the present invention is to provide a needle roller bearing that has a split outer ring and can be easily incorporated into a rotating shaft.

The needle roller bearing according to the present invention includes a cylindrical outer ring formed by connecting a first outer ring member having a central angle larger than 180 ° and a second outer ring member having a central angle smaller than 180 ° in the circumferential direction. And a plurality of needle rollers disposed along the inner diameter surface of the outer ring, a pair of ring portions, and a plurality of column portions disposed between the pair of ring portions, and a needle between adjacent column portions And a cage in which a pocket for accommodating the roller is formed. The inner ring dimension of the outer ring is D, the radius of the needle roller is r, the outer diameter dimension of the cage is d, and the length of the line segment l ₁ connecting the circumferential ends of the inner diameter surface of the first outer ring member is When the center of the column part (referring to “the central part in the circumferential direction”) is positioned on X and the straight line l ₂ that passes through the center of the outer ring and is parallel to the line segment l ₁ , it is adjacent to the column part Assuming that the angle formed by the straight line l ₃ and the straight line l ₂ connecting the center of the needle roller and the center of the outer ring is θ, d <X <D and the following formula (1) is satisfied.

  By satisfying the above dimensional relationship, the first outer ring member can be incorporated without being elastically deformed. As a result, a needle roller bearing that can be easily assembled regardless of the thickness of the outer ring can be obtained.

Preferably, the cage is formed by connecting two cage segments each having a semicircular shape in the circumferential direction. The needle roller bearing satisfies the formula (1) when the _two abutting portions of the cage segment are positioned on the straight line l ₂ , respectively. The distance between adjacent needle rollers is maximized at a position including the divided portion of the cage segment. Therefore, with the above configuration, the split dimension X of the first outer ring member can be reduced, that is, the central angle of the first outer ring member can be increased.

  Preferably, the outer ring is divided into first and second outer ring members by natural splitting. Natural splitting can shorten the manufacturing process and processing time as compared with a method of cutting an outer ring using a cutting tool or the like. As a result, the productivity of the needle roller bearing is improved.

  More preferably, the outer ring is brightly quenched. And the average hardness of an outer ring | wheel is 653Hv or more. By performing bright quenching, mechanical properties necessary for the outer ring, particularly surface hardness (653 Hv or more) can be obtained. In the present specification, “Hv” refers to Vickers hardness.

  As one embodiment, the cage is formed of a metal material subjected to any one of carburizing quenching and carbonitriding quenching. And the average hardness of a cage | basket is 450 Hv or more. In another embodiment, the cage is made of an injection moldable synthetic resin. And the heat-resistant temperature of a cage | basket is 120 degreeC or more.

  A crankshaft support structure according to the present invention includes a crankshaft and the needle roller bearing according to any one of the above that rotatably supports the crankshaft. By adopting the needle roller bearing having the above-described configuration, a crankshaft support structure excellent in assemblability can be obtained.

  According to the present invention, since the outer ring can be incorporated without being deformed by having the above dimensional relation, a needle roller bearing and a crankshaft support structure excellent in assemblability can be obtained.

  With reference to FIGS. 1-3, the needle roller bearing 11 which concerns on one Embodiment of this invention is demonstrated. 1 is a diagram showing the dimensional relationship of the needle roller bearing 11, FIG. 2 is a diagram showing the needle roller bearing 11, and FIG. 3 is an arrow view of the cage 16 as viewed from the direction III in FIG. .

  First, referring to FIG. 2 and FIG. 3, the needle roller bearing 11 includes an outer ring 12, a plurality of needle rollers 15 arranged along the inner diameter surface of the outer ring 12, and a distance between adjacent needle rollers 15. And a retainer 16 for retaining the. The needle roller bearing 11 having the above configuration has an advantage that a high load capacity and high rigidity can be obtained for a small bearing projected area because the outer ring 12 and the needle roller 15 are in line contact with each other. As widely used in all fields.

  Referring to FIG. 2, outer ring 12 is formed by connecting a plurality of arc-shaped outer ring members in the circumferential direction. In addition, one outer ring member having a central angle larger than 180 ° is included in the plurality of outer ring members. In this embodiment, the cylindrical outer ring 12 is configured by combining the first outer ring member 13 having a central angle larger than 180 ° and the second outer ring member 14 having a central angle smaller than 180 °. .

  Next, the cage 16 is formed by connecting two cage segments 17 and 18 each having a semicircular shape in the circumferential direction. Referring to FIG. 3, cage segment 17 includes a pair of ring portions 17a and 17b, and a plurality of pillar portions 17c disposed between the pair of ring portions 17a and 17b. A pocket 17d for accommodating the needle rollers 15 is formed between the adjacent column portions 17c. In addition, since the structure of the holder | retainer segment 18 is also common, description is abbreviate | omitted.

  In addition, since the column portions 17c and 18c are adjacent to each other at the abutting portions of the two cage segments 17 and 18, the interval between the needle rollers 15 arranged on both sides of the abutting portion is larger than the other portions. It has become. Hereinafter, the pillar portions arranged at the circumferential ends of the cage segments 17 and 18 are distinguished from other pillar portions as pillar portions 17e and 18e.

  Next, although the manufacturing method of the outer ring | wheel 12 of the said structure is not specifically limited, For example, it can manufacture with the following method. First, a pipe member as a starting material is turned to form a cylindrical member having predetermined outer diameter dimensions, inner diameter dimensions, and thickness dimensions. Next, heat treatment is performed to obtain predetermined mechanical properties. Specifically, the average hardness is set to 653 Hv or more by bright quenching. In addition, it is desirable to perform tempering in order to reduce residual stress and internal strain caused by bright quenching and to improve toughness and stabilize dimensions.

  Next, grinding is performed on the surface of the cylindrical member, in particular, the inner diameter surface serving as the raceway surface. By setting the surface roughness of the raceway surface to a predetermined value or less, the frictional resistance between the raceway surface and the needle rollers 15 can be reduced, and torque loss and heat generation during rotation can be suppressed. As a result, the needle roller bearing 11 having a long life and high reliability can be obtained.

  Next, the first and second outer ring members 13 and 14 are obtained by applying impact to the cylindrical member and dividing it into two in the circumferential direction. At this time, since the end face of the divided portion is not subjected to grinding or the like, the unevenness when broken is left on the divided surface. When the bearing is used, a cylindrical outer ring 12 is obtained by abutting the corresponding end faces.

  If a notch such as a V-shaped groove is formed in advance on the divided portion (outer diameter surface or end surface), stress concentration occurs at the root of the V-shaped groove, and the portion can be divided using this portion as a base point. As a result, the first and second outer ring members 13 and 14 having a desired central angle can be easily obtained.

  Such a manufacturing method is called “natural split”. Natural splitting can shorten the manufacturing process and processing time as compared with a method of cutting the outer ring 12 using a cutting tool or the like. As a result, the productivity of the needle roller bearing 11 is improved.

  Next, although the manufacturing method of the holder | retainer 16 of the said structure is not specifically limited, For example, it can manufacture with the following method. First, a pipe material made of a metal material such as SCM, SCr, SNCM or the like is processed into a cylindrical member having a predetermined shape. Next, a plurality of pockets 17d and 18d penetrating in the thickness direction are formed on the outer diameter surface of the cylindrical member.

  Next, in order to obtain predetermined mechanical properties, the cylindrical member is subjected to heat treatment. Specifically, the average hardness is set to 450 Hv or more by carburizing or carbonitriding. Further, it is desirable to perform tempering after the above quenching. Then, the cylindrical member is cut at two locations on the circumference (at intervals of 180 °) to obtain semicircular cage segments 17 and 18.

  In the present specification, the “semicircular cage segment” is not limited to one having a strictly central angle of 180 °. That is, those having a central angle slightly smaller than 180 ° but which can be evaluated to be substantially 180 ° are included in the “semicircular cage segment”.

  Specifically, a gap corresponding to the thickness of the cutting tool for cutting the cylindrical member is formed at the abutting portion of the cage segments 17 and 18. Further, when used in a high temperature environment, it is necessary to provide a minute gap in advance in the abutting portion of the cage segments 17 and 18 in consideration of thermal expansion. However, those with a slightly reduced central angle for the above reasons are included in the “semicircular cage segment”.

  Next, various dimensional relationships of the needle roller bearing 11 will be described with reference to FIG. 1 shows the first outer ring member 13, the column portions 17c and 18c (that is, the abutting portions of the cage segments 17 and 18) positioned at the circumferential ends of the cage segments 17 and 18, and the columns. Only the needle rollers 15 accommodated in the pockets 17d and 18d adjacent to the portions 17c and 18c are shown by solid lines, and the others are shown by broken lines.

First, the inner diameter dimension of the outer ring 12 is D, the radius of the needle roller 15 is r, the outer diameter dimension of the cage 16 is d, and the line segment l that connects the circumferential end of the inner diameter surface of the first outer ring member 13 is l. The length of ₁ is assumed to be X (referred to as “division size”). The inner diameter D of the outer ring 12 matches the circumscribed circle diameter of the plurality of needle rollers 15 incorporated in the cage 16.

Further, the abutting portions of the cage segments 17 and 18, that is, the boundary portions of the column portions 17 e and 18 e are positioned on a straight line l ₂ that passes through the center of the outer ring 12 and is parallel to the line segment l ₁ . In this case, the pillar portion 17e indicated by the solid line, the straight line connecting the centers of the outer ring 12 of the needle roller 15 adjacent to 18e and l _3. The angle between the straight line l ₂ and the straight line l ₃ is θ.

  Here, in order to incorporate the first outer ring member 13 without elastic deformation, it is necessary to satisfy d <X <D and the above equation (1). Hereinafter, a method for incorporating the needle roller bearing 11 into the crankshaft 1 will be described with reference to FIGS.

Incidentally, the left side of the equation (1) is adjacent to abutting portions of the retainer segments 17 and 18 (closest to the straight line l ₂₎ needle roller 15 (refer to needle roller 15 shown by the solid line in FIG. 1) It refers to the width dimension of the direction of the straight line l ₂ of roller and cage in position.

  Referring to FIG. 4, first, needle rollers 15 are incorporated into pockets 17d and 18d of cage segments 17 and 18 to form rollers with cages. Next, the cage segments 17 and 18 (rollers with cages) are respectively assembled from the radial direction of the crankshaft 1.

Next, the column portion 17c of the retainer 16, 18c to the first outer ring member 13 in the insertion direction (the direction of arrow A in FIG. 4) perpendicular to the straight line _{l 2} above (which coincides with a straight line _{l 2} in FIG. 1) Arrange it. In this embodiment, two portions abutting portion of the retainer segments 17 and 18, i.e., adjacent needle rollers 15 spacing the largest column portion 17e of, are arranged boundary portion 18e on the straight line l ₂ . Then, the first outer ring member 13 is assembled from the radial direction.

Here, the holding in order to incorporate the first outer ring member 13 without elastic deformation, the direction of the split opening dimension X is orthogonal to the insertion direction of the first outer ring member 13 (the direction of the straight line l ₂₎ It must be larger than the maximum width of the roller with a vessel.

If the width of the roller and the cage is the largest on the straight line l _2, that is, when the maximum width dimension is equal to the outer diameter of the retainer 16 must satisfy d <X. On the other hand, when the width dimension of the roller with cage is the largest at the position of the needle roller 15 adjacent to the abutting portion of the cage segments 17 and 18, the above formula (1) must be satisfied.

Next, referring to FIG. 5, the needle rollers 15 on either side on the straight line l ₂ rotates the roller and retainer so as to be positioned. Here, the slot dimension X is maximum (X = D) when the central angle is 180 °, and therefore X <D is always satisfied in this embodiment. That is, since the slit dimension X is smaller than the circumscribed circle diameter of the needle rollers 15, the first outer ring member 13 can be prevented from falling off by using the above positional relationship.

  Next, referring to FIG. 6, the needle roller bearing 11 is placed on the crankcase 2. Next, referring to FIG. 7, the second outer ring member 14 is arranged continuously in the circumferential direction of the first outer ring member 13 to form a cylindrical outer ring 12. Thereby, the assembly of the needle roller bearing 11 is completed. Further, the needle roller bearing 11 is covered with the bearing cap 3, and the crankcase 2 and the bearing cap 3 (hereinafter collectively referred to as “housing”) are fastened with bolts or the like. Thereby, the assembly of the crankshaft support structure is completed.

  According to the above assembling method, there is no fear of the first outer ring member 13 dropping off during assembling, so the assemblability of the needle roller bearing 11 is improved. Further, since a circlip or the like that prevents the outer ring 12 from falling off can be omitted, it contributes to a reduction in the number of parts.

  Here, by dividing the outer ring 12 unequally, the positions of the abutting portions of the first and second outer ring members 13 and 14 and the abutting portions of the housing are necessarily shifted. As a result, it is possible to effectively prevent stagnation in the radial direction of the crankshaft support structure.

  Note that “slack” refers to a state in which the crankcase 2 and the bearing cap 3, and the first outer ring member 13 and the second outer ring member 14 are assembled while being displaced in the radial direction. This becomes a problem when the outer ring is divided into two equal parts (center angle 180 °) and the abutting part of the outer ring and the abutting part of the housing coincide.

  In the above embodiment, the outer ring 12 is divided into two parts (first and second outer ring members 13 and 14). However, the present invention is not limited to this, and if one central angle is 180 ° or more. It may be divided into three or more.

In the above embodiment, the pillar portion 17e when incorporating the first outer ring member 13, an example is shown disposed over the straight line l ₂ and 18e, the other column portion 17c, even when arranged 18c, If the above various dimensional relationships are satisfied, the effects of the present invention can be obtained. However, since the value of the left side are needle roller 15 to be of the formula (1) becomes smaller the farther from the straight line l _2, if the method described above, reducing the split opening dimension X of the first outer ring member 13, That is, the central angle of the first outer ring member 13 can be increased.

  Further, in the above-described embodiment, the example in which the cage 16 is configured by the two semicircular cage segments 17 and 18 has been described. The configuration can be adopted. For example, three cage segments may be connected in the circumferential direction to form a cylindrical cage, or the central angle of each may be different.

  Alternatively, it may be an integrated cage having a dividing line extending in the axial direction at one place on the circumference (so-called “C-type cage”). In this case, since it is incorporated into the crankshaft 1 while being elastically deformed in the direction of extending the dividing line, it is desirable to form the resin material with high elastic deformability. The resin material is preferably a synthetic resin that can be injection-molded, and since it is used in a high-temperature environment, the heat-resistant temperature is preferably 120 ° C. or higher. Specifically, nylon 66, nylon 46, or the like can be employed.

  Further, referring to FIG. 8, a convex portion 26e protruding toward the other side is formed on one side end surface of the divided portion, and a concave portion 26f that receives the convex portion 26e is formed on the other side end surface of the divided portion. Then, it is desirable to obtain the cylindrical cage 26 by engaging the convex portion 26e and the concave portion 26f. Since other configurations are the same as those of the cage 16, description thereof is omitted.

  Furthermore, the needle roller bearing 11 can be applied to a crankshaft of any engine such as an automobile or a motorcycle. 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 needle roller bearings.

It is a figure which shows the various dimensional relationship of the needle roller bearing shown in FIG. It is a figure which shows the needle roller bearing which concerns on one Embodiment of this invention. FIG. 3 is an arrow view of the cage shown in FIG. 2 viewed from the direction of arrow III. It is a figure which shows the process of incorporating the needle roller bearing shown in FIG. 2 in a crankshaft, Comprising: It is a figure which shows the state which integrated the roller with a retainer. It is a figure which shows the process of incorporating the needle roller bearing shown in FIG. 2 in a crankshaft, Comprising: It is a figure which shows the state which integrated the 1st outer ring member in the crankshaft. It is a figure which shows the process of incorporating the needle roller bearing shown in FIG. 2 in a crankshaft, Comprising: It is a figure which shows the state which mounted the needle roller bearing in the crankcase. 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 butt | matching part of the holder | retainer which concerns on other embodiment. It is a figure which shows the conventional crankshaft.

Explanation of symbols

  1,101 Crankshaft, 2 Crankcase, 3 Bearing cap, 11 Needle roller bearing, 12 Outer ring, 13, 14 Outer ring member, 15 Needle roller, 16, 26 Cage, 17, 18 Cage segment, 17a, 17b , 18a, 18b, 26a, 26b Ring part, 17c, 18c, 17e, 18e, 26c Column part, 17d, 18d, 26d Pocket, 26e Convex part, 26f Concave part.

Claims (7)

A cylindrical outer ring formed by connecting a first outer ring member having a central angle larger than 180 ° and a second outer ring member having a central angle smaller than 180 ° in the circumferential direction;
A plurality of needle rollers disposed along the inner diameter surface of the outer ring;
A cage including a pair of ring portions and a plurality of column portions arranged between the pair of ring portions, and a pocket for accommodating the needle rollers is formed between the adjacent column portions. ,
The inner ring dimension of the outer ring is D, the radius of the needle roller is r, the outer diameter dimension of the cage is d, and the length of the line segment l ₁ connecting the circumferential ends of the inner diameter surface of the first outer ring member. And when the center of the column part is positioned on a straight line l ₂ that passes through the center of the outer ring and is parallel to the line segment l ₁ , the center of the needle roller adjacent to the column part and the center If the angle between the straight line l ₃ connecting the center of the outer ring and the straight line l ₂ is θ,
Needle roller bearings satisfying d <X <D and formula (1).

The cage is formed by connecting two cage segments each having a semicircular shape in the circumferential direction,
The needle roller bearing according to claim 1, wherein the needle roller bearing satisfies the formula (1) when _two abutting portions of the cage segment are positioned on the straight line l2, respectively.   The needle roller bearing according to claim 1 or 2, wherein the outer ring is divided into the first and second outer ring members by natural splitting. The outer ring has been subjected to bright quenching,
The needle roller bearing according to any one of claims 1 to 3, wherein the outer ring has an average hardness of 653 Hv or more. The cage is formed of a metal material subjected to any one of carburizing quenching and carbonitriding quenching,
The needle roller bearing according to any one of claims 1 to 4, wherein the cage has an average hardness of 450 Hv or more. The cage is formed of a synthetic resin that can be injection molded,
The needle roller bearing according to any one of claims 1 to 4, wherein the heat resistant temperature of the cage is 120 ° C or higher. A crankshaft,
A crankshaft support structure comprising the needle roller bearing according to any one of claims 1 to 6, which rotatably supports the crankshaft.

Images