JP2009014078A - Needle roller bearing and crankshaft supporting structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a needle roller bearing which is easily installed to a rotational shaft. <P>SOLUTION: The needle roller bearing 11 comprises: a cylindrical outer ring formed by circumferentially connecting first outer members 13 having a center angle larger than 180°, and second outer ring members having a center angle smaller than 180°; and a plurality of needle rollers 15 disposed along an inner diameter face of the outer ring. When an inner diameter size of the outer ring is D, and length of a line segment connecting between circumferential end parts of the inner diameter face of the first outer ring member 13 is X, the expression of 0<(D-X)/D≤0.003 is satisfied. <P>COPYRIGHT: (C)2009,JPO&INPIT

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. 11, 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. And the recessed part which latches a tool is provided in the circumferential direction both end surfaces of the 1st outer ring member, respectively. As in the above-described configuration, the assembly of the needle roller bearing is improved by providing recesses on both circumferential end surfaces of the first outer ring member and locking the tool used when expanding the slit.

  Preferably, 0 <(D−X) /D≦0.003 where D is the inner diameter dimension of the outer ring and X is the length of the line segment connecting the circumferential ends of the inner diameter surface of the first outer ring member. Meet. If the above dimensional relationship is satisfied, the amount of elastic deformation of the outer ring during assembly can be reduced (0.3% or less of the inner diameter dimension D). As a result, even if the outer ring is thick to some extent, it can be easily incorporated into the rotating shaft.

  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, in particular, surface hardness (653 Hv or more) can be obtained. In the present specification, “Hv” refers to Vickers hardness.

  Preferably, the needle roller bearing further includes a split type retainer having a split line extending in the axial direction on the circumference. In addition to the outer ring, the cage is also divided, so that it can be easily incorporated into the rotating shaft.

  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, the needle roller bearing and the crank that are excellent in assemblability are provided by providing the recesses on both circumferential end surfaces of the first outer ring member and locking the tool used when expanding the slit. A shaft support structure can be obtained.

  With reference to FIGS. 1-5, the needle roller bearing 11 which concerns on one Embodiment of this invention is demonstrated. 1 is a view showing the needle roller bearing 11, FIG. 2 is an enlarged view showing a circumferential end surface of the first outer ring member 13, FIG. 3 is a view showing another embodiment of FIG. 2, and FIG. FIG. 5 is a diagram showing the dimensional relationship of the needle roller bearing 11 when the cage 16 is viewed from the direction of the arrow IV in FIG.

  First, referring to FIG. 1, the needle roller bearing 11 maintains an interval between the outer ring 12, a plurality of needle rollers 15 arranged along the inner diameter surface of the outer ring 12, and the adjacent needle rollers 15. And a cage 16. 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. 1, 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, referring to FIG. 2, recesses 13 a are provided on both circumferential end surfaces of the first outer ring member 13. The recess 13a is provided to lock a tool used when the slit of the first outer ring member 13 is widened.

  2 shows an example in which the recess 13a is provided at a position in contact with the inner diameter surface (track surface) of the first outer ring member 13, but in this configuration, the inner diameter of the first outer ring member 13 serving as the track surface is shown. There is a step on the surface. This may damage the surface of the needle roller 15 or hinder the smooth rolling of the needle roller 15.

  Therefore, referring to FIG. 3, the recess 13 b as another embodiment is located at the center of the first outer ring member 13. In this way, by forming the recess 13b surrounded by the side walls on the four sides (in FIG. 2, the three sides of the recess 13a are surrounded by the side walls), smooth rolling of the needle rollers 15 is prevented. Absent.

  Furthermore, the position and shape of the recess (rectangular in the above embodiment) are not limited to the embodiment shown in FIGS. 2 and 3, and any structure that can lock the tool can be adopted.

  1 and 4, the retainer 16 is formed by connecting two retainer segments 17, 18 each having a semicircular shape in the circumferential direction. Referring to FIG. 4, cage segment 17 includes a pair of ring portions 17a and 17b, and a plurality of pillar portions 17c arranged 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.

  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. Further, a recess 13 a is formed on the circumferential end surface of the first outer ring member 13. 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. First, the inner diameter D of the outer ring 12, and a length of a line l ₁ connecting circumferential ends of the inner surface of the first outer ring member 13 and the X (referred to as "split inlet dimension"). 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.

The slot dimension X is maximum (X = D) when the center angle of the first outer ring member 13 is 180 °, and therefore X <D is always satisfied in this embodiment. Therefore, when the first outer ring member 13 is incorporated in a roller with cage (which indicates a state in which the needle rollers 15 are incorporated in the pockets 17d and 18d), the elastic deformation amount δ of the slit is δ = DX (= δ ₁ + δ ₂ ).

  Here, the first outer ring member 13 according to the present invention sets various dimensions so as to satisfy 0 <δ / D <0.003 (hereinafter referred to as “Expression 1”). For example, when the inner diameter D of the outer ring 12 is 40 mm and the slot size X is 39.9 mm, the amount of elastic deformation δ is 0.1 mm (δ / D = 0.005).

  A method of incorporating the needle roller bearing 11 into the crankshaft 1 will be described with reference to FIGS. 6 is a view showing a state in which the roller with cage is incorporated, FIG. 7 is a view in which the first outer ring member 13 is incorporated, and FIG. 8 is a diagram showing the needle roller bearing 11 placed on the crankcase 2. FIG. 9 is a diagram showing a state after the completion of assembly.

  Referring to FIG. 6, 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 first outer ring member 13 is incorporated into the roller with cage while the tool 21 is locked to the recess 13a and the slit is widened (X + δ). At this time, since the elastic deformation amount δ of the slot necessary for incorporation is limited to the range of the expression 1, it can be easily incorporated even if the thickness of the first outer ring member 13 is thick. Moreover, since the slit can be widened using the tool 21, the assemblability of the needle roller bearing 11 is further improved.

  It is also possible to consider a method in which the recesses 13a are not provided at both circumferential end surfaces of the first outer ring member 13 and the tool 21 is directly locked to the inner diameter surface (track surface) of the first outer ring member 13 to widen the split slot. It is done. However, according to this method, the raceway surface may be damaged during assembly, and the smooth rolling of the needle rollers 15 may be hindered. Therefore, in order to solve such a problem, it is desirable to provide recesses 13a and 13b as shown in FIG. 2 or 3 and to lock the tool 21 in the recesses 13a and 13b.

  Next, referring to FIG. 7, after incorporating the first outer ring member 13 into the roller with cage, the first outer ring member 13 is returned to the natural state (refers to a state where it is not elastically deformed). At this time, since the split port dimension X is smaller than the circumscribed circle diameter (= D) of the needle rollers 15, it is possible to prevent the first outer ring member 13 from falling off in the subsequent assembly process.

  Next, referring to FIG. 8, the needle roller bearing 11 is placed on the crankcase 2. Next, referring to FIG. 9, 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.

  The “spinning” 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 one central angle may exceed 180 °. For example, it may be divided into three or more.

  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. 10, 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 for a multi-cylinder engine in which crank arms 103 are arranged at both ends of a shaft portion 102 as shown in P portion of FIG. By applying to the crankshaft 101, 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 needle roller bearing which concerns on one Embodiment of this invention. It is a figure which shows the circumferential direction end surface of the 1st outer ring member shown in FIG. It is a figure which shows the other form of FIG. It is the arrow line view which looked at the holder | retainer shown in FIG. 1 from the direction of arrow IV. 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 process of incorporating the needle roller bearing shown in FIG. 1 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. 1 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. 1 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, 13a, 13b recess, 15 needle roller, 16 cage, 17, 18 cage segment, 17a, 17b, 18a, 18b Ring, 17c, 18c Column, 17d, 18d Pocket, 17e Convex, 18e Concave, 21 Tool.

Claims (8)

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 needle roller bearing in which recesses for engaging the tool are provided on both circumferential end surfaces of the first outer ring member. When the inside diameter of the outer ring D, and a length of a line l ₁ connecting circumferential ends of the inner surface of the first outer ring member is X,
The needle roller bearing according to claim 1, wherein 0 <(D−X) /D≦0.003 is satisfied.   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 needle roller bearing according to any one of claims 1 to 4, further comprising a split type retainer having a parting line extending in an axial direction on a circumference. The cage is formed of a metal material subjected to any one of carburizing quenching and carbonitriding quenching,
The needle roller bearing according to claim 5, 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 claim 5, 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 4, which rotatably supports the crankshaft.

Images