JP2011038587A - Bearing device for crankshaft - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve durability of a bearing device by preventing generation of an excessively abraded portion caused by eccentric frictional force generated in the bearing device for a crankshaft using a halved rolling bearing. <P>SOLUTION: A journal cap 14 is fastened and fixed to the fixing portion 12 of a cylinder block 102 by a bolt 116, a needle bearing 15 is mounted on a cylindrical retaining surface 13 formed with semicylindrical recessed surfaces 12a, 14a in an opposed relationship, and the journal portion 100a of the crankshaft 100 is rotatably retained. The outer race 16 of the needle bearing 15 is composed of semicylindrical divided pieces 16a, 16b divided into two by a natural split process, and the mating surfaces 24a, 24b of the divided pieces are formed into a flat surface inclined to a horizontal surface H and are formed parallel to one another. The mating surfaces are arranged in a position displaced by an angle α in the circumferential direction of the journal portion 100a with respect to the horizontal surface H, and the end 16<SB>a1</SB>of the divided piece 16<SB>a</SB>is inclined on the mating surface 24a toward the side of the cylinder block. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a crankshaft bearing device that supports a crankshaft of an internal combustion engine (engine) mounted on a vehicle or the like using a rolling bearing.

  A crankshaft of an internal combustion engine mounted on a vehicle or the like has a crank arm and a balance weight projecting radially outward, and a large-diameter portion such as a flywheel is attached to an end portion. For this reason, the bearing that supports the crankshaft cannot be attached to the inner bearing portion or the journal portion through the overhanging portion or the large diameter portion, and is thus divided into two parts and attached to the crankshaft.

Conventionally, a slide bearing has been used as a bearing for such a crankshaft. However, the sliding bearing has a problem that the frictional resistance during rotation is large and an oil film needs to be formed on the boundary surface, and it takes time to form the oil film at the start.
Therefore, recently, it has been proposed to use a rolling bearing that has a low frictional resistance and does not require a preparation time for starting, thereby reducing the fuel consumption of the vehicle.

  Patent Document 1 (Japanese Patent Laid-Open No. 2008-232279) discloses an example in which a needle bearing divided into two is used in a bearing device that rotatably supports a crankshaft of an internal combustion engine. This bearing device will be described with reference to FIG. In FIG. 8, the needle bearing 108 is interposed between the fixed portion 104 of the cylinder block 102, the journal cap 106 corresponding to the fixed portion 104, and the journal portion 100 a of the crankshaft 100. The crankshaft 100 includes a crankpin 100b, a counterweight 100c, and the like.

  The needle bearing 108 is divided into two in the circumferential direction and formed into a semi-cylindrical pair of split pieces 110a and 110b, and a two-split outer race 110, and an inner peripheral surface of the outer race 110 as a raceway surface. A plurality of rollers (needles) 112 and a retainer 114 formed of a pair of separation pieces 114a and 114b that hold the plurality of rollers 112 at a predetermined interval in the circumferential direction and are separated in the circumferential direction to form a semi-annular shape. It is configured. A plurality of pocket portions P penetrating inward and outward in the radial direction are provided in the retainer 114 at equal intervals along the circumferential direction, and the rollers 112 are accommodated in the respective pocket portions P. The rollers 112 roll between the raceway surfaces respectively formed on the inner peripheral surface of the outer race 110 and the outer peripheral surface of the journal portion 100a.

  The needle bearing 108 is accommodated in a cylindrical holding surface formed by facing a concave surface 104a having a semi-cylindrical shape provided in the fixed portion 104 and a concave surface 106a having a semi-cylindrical shape provided in the journal cap 106. Is done. That is, the outer race 110 composed of a pair of divided pieces 110a and 110b is integrally fixed to the fixing portion 104 and the cap 106, and the journal portion 100a is connected as an inner ring so as to be relatively rotatable. A female screw hole 104 h corresponding to the bolt 116 is formed in the fixing portion 104, and the bolt 116 is fastened through an insertion hole 106 h formed in the journal cap 106.

  Patent Document 2 (Japanese Patent Laid-Open No. 2003-214442) discloses a two-part crankshaft bearing device using a needle bearing. Among rolling bearings, the needle bearing has advantages such as a small cross-sectional height, which can save bearing space, reduce the size and weight of the crank chamber, and increase the load capacity and maximum allowable load.

  In Patent Document 2, as a background art, “a split-type rolling bearing has a reduced roundness of a raceway surface in a state where it is assembled to a mounted member such as a crankshaft, or a minute step on a parting line portion of the raceway surface. As a result, a portion where the rolling element is strongly rubbed is formed on the raceway surface, and the flaking phenomenon in which the raceway surface and the rolling surface of the rolling body are peeled off in a scaly manner when used for a long period of time. The durability of the bearing is significantly reduced and the roundness of the raceway surface is reduced, and the cause of minute steps in the parting line of the raceway surface is to improve the hardness of the raceway surface. It is considered that the residual stress when the heat treatment is performed is released at the time of division, and the shape of the divided half of the race is slightly distorted. "

  Therefore, the bearing disclosed in Patent Document 2 divides the raceway into two semi-cylindrical parts, and forms a step portion on the mating surface of the two raceway half parts when mounted on the crankshaft. By using the stepped portions to fit and position the raceway half halves, the roundness of the roller raceway surface is ensured, and the divided portions can be formed on a smooth surface without steps. Hereinafter, the configuration of the mating surface of the outer race of the bearing disclosed in Patent Document 2 will be described with reference to FIG.

  In FIG. 9, the mating surfaces 122 of the pair of split pieces 120a and 120b constituting the outer race 120 include first split surfaces 126a and 126b extending radially outward from the inner peripheral surface 124 of the outer race 120, and the first split surfaces 126a and 126b. Second divided surfaces 128a and 128b extending in the circumferential direction from the tips of the divided surfaces 126a and 126b, and third divided surfaces 130a and 130b extending radially outward from the tips of the second divided surfaces 128a and 128b. Is formed.

  In a state where the divided pieces 120a and 120b are assembled to the journal portion 100a of the crankshaft, the first divided surfaces 126a and 126b are formed so as to press each other. The second divided surfaces 128a and 128b are in contact with each other in the assembled state, and restrict the relative movement of the divided piece 120a and the divided piece 120b with respect to the radial direction. The third divided surfaces 130a and 130b are opposed to each other with a gap s therebetween, and are formed so as to allow relative movement of the divided pieces 120a and 120b in the circumferential direction.

  Thus, by forming the gap s between the third divided surfaces 130a and 130b, when the divided pieces 120a and 120b are fitted to each other, the first divided surfaces 126a and 126b are reliably in contact with each other. In addition, the pressing force generated between the divided pieces 120a and 120b is applied only to the first divided surfaces 126a and 126b in the assembled state.

  With this configuration, even in a temporarily assembled state that is not actually assembled to the crankshaft, the mating surface 122 can be positioned in both the circumferential direction and the radial direction, so that it can be positioned in the same state as that assembled to the crankshaft. For this reason, in the temporarily assembled state, the raceway surface is subjected to heat treatment, polishing, or the like to finally finish the inner peripheral surface of the outer race 120, and then the raceway half halves are separated from each other and attached to the mounted member. As a result, the roundness of the roller raceway surface can be ensured, and the divided portion can be formed on a smooth surface with no steps, reducing the resistance when the crankshaft rotates and enabling high-speed rotation of the crankshaft. . In addition, generally the outer race which comprises a rolling bearing is ensuring the intensity | strength of a rolling bearing by making it into steel which has high hardness with respect to the cylinder block made from aluminum.

  Processing of the divided pieces constituting the outer race includes natural splitting and machine splitting. Of these, natural splitting is a process in which a notched portion is formed on one or both surfaces of a quenched and annealed member, and a concentrated stress is generated in the notched portion by driving a wedge or the like to cause breakage. Machine splitting is a process of cutting using wire cutting or the like. Natural splitting has the advantage that positioning of the mating surfaces of the fractured pieces is easy because fine irregularities along the boundaries of the crystal grains are formed on the fracture surface. Natural split processing is disclosed in, for example, Patent Document 3 (Japanese Utility Model Publication No. 63-46725) and Patent Document 4 (Japanese Patent Application Laid-Open No. 10-184664).

  In the crankshaft bearing device, the roundness of the cylindrical holding surface formed by the semi-cylindrical concave surface 104a provided on the fixed portion 104 of the cylinder block 102 and the semi-cylindrical concave surface 106a provided on the journal cap 106 is determined. In order to maintain this, a method is employed in which the concave surfaces 104a and 106a are processed in a state in which the journal cap 106 is fastened and fixed to the cylinder block 102 with a bolt 116. Further, the outer race 110 is divided into two parts by natural splitting in order to facilitate positioning of the mating surfaces of the split pieces after fracture.

  FIG. 10 shows a bearing device in which after the concave surfaces 104a and 106a are machined, the needle bearing 108 is mounted on the journal portion 100a of the crankshaft. FIG. 10 shows the posture when the internal combustion engine is assembled. Contact surfaces 117a and 117b between the journal cap 106 and the cylinder block fixing portion 104 are positioned on the horizontal plane H, and the mating surfaces 118a and 118b with which the split pieces 110a and 110b abut each other are shifted from the horizontal plane H in the circumferential direction. Placed in position. That is, the plane C passing through the mating surface and the center O is at a position inclined by an angle α (for example, 5 to 10 °) clockwise from the horizontal plane H around the center O of the journal portion 100a of the crankshaft.

Japanese Patent Laying-Open No. 2008-232279 (FIG. 4) JP 2003-214442 A Japanese Utility Model Publication No. 63-46725 JP-A-10-184673

  FIG. 11 shows changes in the shape of the concave surfaces 104a and 106a before and after the needle bearing 108 is fastened and fixed to the cylinder block with the bolt 116. In FIG. 11, P is a perpendicular line passing through the center O, D indicates the shape of the concave surfaces 104 a and 106 a before tightening fixing, and E indicates the shape of the concave surfaces 104 a and 106 a after tightening fixing. As shown in the figure, the concave shape D before tightening and fixing has a bowl shape extending in the vertical direction, and then a tightening force (force F in FIG. 12) is applied from the vertical direction by tightening with the bolt 116. Thus, the concave shape E after tightening and fixing becomes a shape in which the roundness of the concave surfaces 104a and 106a returns. As described above, since the concave surfaces 104a and 106a are processed into a perfect circle after the needle bearing 108 is tightened and fixed, the concave surfaces 104a and 106a have a bowl shape before the fixing.

  For this reason, if the divided pieces 110a and 110b are to be mounted on the concave surfaces 104a and 106a before tightening and fixing, a force to sandwich the divided pieces from both sides in the horizontal direction is applied. In order to avoid the effect of this pinching force acting on the split pieces 110a and 110b, and when the journal cap is displaced during engine operation due to a difference in thermal expansion coefficient, the outer race is directly affected by the influence. In order to avoid this, the mating surfaces 118a and 118b of the outer race 110 are arranged at positions shifted by an angle α from the contact surfaces 117a and 117b.

Since the mating surfaces 118a and 118b are shifted from the horizontal plane H by the angle α in the clockwise direction, one end portion 110a1 of the divided piece 110a _first enters the divided piece 110b side. At this time, the concave 104a, the residual stress of the impact and the split piece itself pinching force 106a, the lift end portion 110a _1, deviate G between the end face of the split piece 110b (see FIG. 13). Due to this deviation G, a deviation also occurs on the other mating surface 118b. The amount of misalignment between the mating surfaces 118a and 118b is usually about 5 to 40 μm (0.005 mm to 0.04 mm) (the total value of the misalignment amounts G at the mating surfaces 118a and 118b).

  After the needle bearing 108 is fastened and fixed to the cylinder block, the tightening force F is applied to the concave surfaces 104a and 106a from the vertical direction, and the roundness of the concave surfaces 104a and 106a is restored, but the misalignment of the mating surfaces 118a and 118b is not reduced. There is a case. When the needle bearing 108 is mounted on the journal portion 100a with a gap between the mating surfaces 118a and 118b, a friction portion is generated in the needle bearing 108. Therefore, an excessive wear portion is generated in the roller 112 or the like, which may cause damage to the needle bearing 108 or decrease its durability.

  Since the mating surface of the outer race divided piece disclosed in Patent Document 2 has a complicated shape composed of three divided surfaces, precise processing such as formation of a gap s is required. Therefore, processing takes time and labor, and the cost becomes high. In addition, since the stepped portion is provided on the mating surface, when the misalignment occurs on the mating surface, depending on the direction of the misalignment, the stepped portion may become an obstacle and it may be difficult to eliminate the misalignment.

  In the present invention, in view of the problems of the prior art, when a two-part rolling bearing is used as a bearing for supporting a crankshaft, tightening and fixing are performed by reducing the deviation of the mating surfaces of the divided pieces constituting the outer race. It is an object of the present invention to improve the durability of the bearing by preventing the occurrence of excessive wear due to the uneven friction force generated in the bearing.

In order to achieve the above object, the crankshaft bearing device of the present invention includes:
The crankshaft of an internal combustion engine is supported by a split type rolling bearing, and the split type rolling bearing is fitted and fixed to a cylindrical holding surface formed by combining a semicylindrical concave surface formed on each of a cylinder block and a cap member. In the crankshaft bearing device,
The outer race constituting the split type rolling bearing is constituted by two semi-cylindrical divided pieces, and the mating surface of the semi-cylindrical divided pieces is inclined with respect to a plane including the axial center line of the outer race. It will be.

  As described above, the horizontal pinching force due to the shape change of the concave surface provided in the cylinder block or the cap member acts on the outer race. In the present invention, since the mating surfaces of the two semi-cylindrical segment pieces are inclined with respect to the plane including the axial center line of the outer race, the mating surfaces of both segment pieces can be easily fitted to each other. Can be reduced. Therefore, when the cap member is fastened and fixed to the cylinder block with a bolt or the like, the misalignment of the mating surfaces can be reduced. Further, the displacement of the mating surfaces after tightening and fixing can be eliminated by the tightening force applied at the time of tightening and fixing.

  Therefore, since no partial friction force is generated in the components of the rolling bearing and no excessive wear occurs, the rolling bearing is not damaged and the durability of the bearing can be maintained. In addition, since it is only necessary to incline the mating surface of the semi-cylindrical divided pieces, it can be processed at low cost.

  In the bearing device of the present invention, the mating surfaces of the two semi-cylindrical divided pieces are arranged differently in the circumferential direction of the crankshaft with respect to the contact surface where the cylinder block and the cap member are in contact, and the semi-cylinder of the cap member The semi-cylindrical divided piece accommodated in the concave shape has a mating surface on the side where the semi-cylindrical divided piece enters the cylinder block side, and the tip of the one semi-cylindrical divided piece is inclined toward the outer peripheral side toward the cylinder block side. It is good to form like this.

  In order to reduce the influence of changes in the shape of the cylinder block and cap member before and after tightening by bolts, the mating surface of the semi-cylindrical divided pieces is shifted in the circumferential direction from the position of the contact surface between the cylinder block and the cap member. At this time, of both ends of the semi-cylindrical divided piece arranged on the cap member side, the tip that has entered the cylinder block side comes into contact with the other divided piece first. Since the tip is inclined outward, when the cap member is fastened to the cylinder block, the tip is directed outward at the mating surface, so that deviation at the mating surface can be reduced.

  In the conventional bearing device, the first misalignment occurs at the mating surface that comes into contact first, and the misalignment at this mating surface causes the misalignment of the other mating surface. In the bearing device of the present invention, as described above, the misalignment at the time of abutting can be reduced with the mating surface that has been in contact with the first, so that the misalignment with the other mating surface can also be reduced. Further, the displacement of the mating surfaces after tightening and fixing can be eliminated by the tightening force applied at the time of tightening and fixing.

  In the bearing device of the present invention, the mating surfaces of the semi-cylindrical divided pieces are arranged on the same plane as the contact surface where the cylinder block and the cap member are in contact, and the both mating surfaces are symmetrical with respect to the axial center line of the outer race. It is good to arrange | position in the square shape direction or reverse square shape direction so that it may become. As a result, the mating surfaces are simultaneously formed at two locations. However, by disposing the mating surfaces in the C-shaped direction or the reverse C-shaped direction, the mating surfaces can be easily fitted to each other, so that deviation at the time of matching can be reduced. . For this reason, it is possible to reduce the displacement of the mating surface before tightening and fix the misalignment of the mating surface after tightening and fixing by the tightening force applied at the time of tightening and fixing.

  In the bearing device of the present invention, it is preferable to form irregularities along the axial center line direction of the outer race on the mating surface of the semi-cylindrical divided pieces. As a result, when the two semi-cylindrical divided bodies are assembled, the presence of the concavo-convex portion facilitates positioning in the direction of the center line of the outer race axis.

  In the bearing device of the present invention, the semi-cylindrical divided pieces may be divided and formed from a cylindrical outer race material by natural split processing. As a result, fine irregularities along the crystal grains generated on the divided surfaces are generated, so that when the bearing device is assembled, the positioning of both divided pieces is facilitated, and the function of suppressing the misalignment of the mating surfaces by the fine irregularities. There are benefits to be born.

  In addition to the above-described configuration in which the semi-cylindrical divided pieces are divided and formed by natural split machining, a knock pin insertion hole is formed at a position where the mating surfaces of the two semi-cylindrical divided pieces face each other, and the knock pin is inserted into the knock pin insertion hole. It is preferable that both split pieces are positioned in the axial direction with the dowel pin. Thus, with a simple configuration using a knock pin, when the two divided pieces are reassembled, the axial positioning of the divided pieces is facilitated, and the axial deviation of the divided pieces can be eliminated.

  According to the crankshaft bearing device of the present invention, the crankshaft of the internal combustion engine is supported by the split-type rolling bearing, and the split-type rolling bearing is aligned with the semi-cylindrical concave surface formed on the cylinder block and the cap member, respectively. In the crankshaft bearing device that is fitted and fixed to the cylindrical holding surface formed in this way, the outer race that constitutes the split type rolling bearing is composed of two semicylindrical divided pieces, and the semicylindrical divided portion By tilting the mating surfaces of the pieces with respect to the plane including the axial center line of the outer race, the mating surfaces of the two split pieces can be easily fitted to each other, so that the displacement of the mating surfaces before fastening can be reduced. .

  Accordingly, when the cap member is fastened and fixed to the cylinder block with a bolt or the like, the misalignment of the mating surfaces can be reduced. Further, the displacement of the mating surfaces after tightening and fixing can be eliminated by the tightening force applied at the time of tightening and fixing. Therefore, it is possible to prevent the occurrence of excessive friction due to the partial friction force generated in the two-part rolling bearing, prevent damage to the rolling bearing, and improve durability. In addition, the mating surface can be processed at low cost.

It is a front view concerning a 1st embodiment of a bearing device of the present invention. FIG. 2 is a partially enlarged view of FIG. 1 showing a mating surface before and after mounting of the bearing device in the first embodiment. It is a front view which concerns on 2nd Embodiment of the bearing apparatus of this invention. It is a front view which concerns on the modification of the said 2nd Embodiment. It is a perspective view of the outer race which concerns on 3rd Embodiment of the bearing apparatus of this invention. It is a perspective view of the outer race which concerns on the modification of the said 3rd Embodiment. It is a perspective view which expand | deploys and shows the outer race which concerns on 4th Embodiment of the bearing apparatus of this invention. It is a perspective view which expands and shows a bearing device for crankshafts. It is sectional drawing of the mating surface of the outer race of the conventional bearing for crankshafts. It is a front view of the conventional bearing device for crankshafts. It is explanatory drawing which shows the shape change of the cylinder block side holding surface which accommodates the conventional bearing for crankshafts. It is explanatory drawing which shows the behavior of the outer race of the bearing apparatus for crankshafts of FIG. It is the B section enlarged view in FIG.

  Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the component parts described in this embodiment are not intended to limit the scope of the present invention to that unless otherwise specified.

(Embodiment 1)
A first embodiment of a crankshaft bearing device of the present invention will be described with reference to FIG. FIG. 1 shows a crankshaft bearing device 10 of this embodiment mounted on a cylinder block constituting an internal combustion engine mounted on a vehicle or the like, and this figure corresponds to FIG. 10 showing a conventional crankshaft bearing device. And, it is shown in a posture when the internal combustion engine is assembled. In FIG. 1, a semi-cylindrical concave surface 12 a is formed in the fixing portion 12 of the cylinder block. On the other hand, the journal cap 14 also has a semi-cylindrical concave surface 14a. The needle bearing 15 is accommodated in a cylindrical holding surface 13 formed by the concave surface 12a and the concave surface 14a facing each other.

  The needle bearing 15 includes an outer race 16 composed of semi-cylindrical divided pieces 16a and 16b, a retainer 18 composed of a pair of semi-annular separation pieces 18a and 18b disposed inside the outer race 16, and a separation piece 18a. , 18b, and a plurality of rollers (needles) 20 rotatably mounted. The split piece 16a and the separation piece 18a are accommodated in the concave surface 14a of the journal cap 14, and the split piece 16b and the separation piece 18b are accommodated in the concave surface 12a of the fixed portion 12, and the journal portion 100a of the crankshaft is sandwiched from above and below. The journal cap 14 is fastened and fixed to the fixing portion 12 with a bolt (not shown).

  The component device of the needle bearing 15 is made of a material having high strength and high wear resistance, and the roller 20 has a cylindrical shape with a small diameter and a slight axial length. Therefore, since the bearing device 10 has a large load capacity and a small cross-sectional height, it has an advantage that a bearing space can be saved. The roller 20 is in contact with the outer peripheral surface of the journal portion 100a of the crankshaft, and rotatably supports the journal portion 100a while rotating.

  Contact surfaces 22a and 22b where the fixed portion 12 and the journal cap 14 come in contact are located on a horizontal plane H passing through the center O of the journal portion 100a. On the other hand, the mating surfaces 24a and 24b formed at both ends of the divided pieces 16a and 16b are provided at positions shifted clockwise from the horizontal plane H by an angle α (for example, 5 to 10 °) with the center O as the center. It has been. The mating surfaces 24a and 24b form a plane inclined with respect to the plane C passing through the mating surfaces 24a and 24b and the center O, and the mating surfaces are formed to be parallel to each other.

In the mating surfaces 24a, the distal end of the divided pieces 16a are inclined in the outer peripheral side, the extension end portion 16a ₁ is entered into the concave 12a side. Divided piece 16b tip contacts the extension end portion 16a ₁ is inclined to the inner peripheral side. In the mating surface 24b, the arrangement is reversed. The tip of the segment piece 16a is inclined toward the inner peripheral side, and the tip of the segment piece 16b is inclined toward the outer peripheral side.

The concave surfaces 12a and 14a are processed in a state where the journal cap 14 is fastened and fixed to the fixing portion 12 with a bolt. Accordingly, the roundness during operation of the holding surface 13 that accommodates the needle bearing 15 is maintained.
However, as shown in FIG. 11, when the journal cap 14 is removed from the fixed portion 12, the diameter of the concave surfaces 12 a and 14 a is reduced in the direction of the horizontal plane H to the concave surfaces 12 a and 14 a due to residual stress of the fixed portion 12 and the journal cap 14. Changes in shape. With this shape change, a horizontal pinching force acts on the outer race 16.

Due to the clamping force and the residual stress of the outer race itself, conventionally, when the bearing is assembled, as shown in FIGS. 12 and 13, a deviation G has occurred on the mating surfaces 118 a and 118 b.
This is because the mating surfaces 118a and 118b are formed in substantially the same direction as the deformation direction of the concave surfaces 104a and 106a, so that the influence of the deformation of the concave surfaces 104a and 106a is directly affected, and the divided pieces 110a and 110b are formed into the concave surface 104a, It is thought that it follows the deformation of 106a. Moreover, since this deviation G is considered to occur first on the mating surface 118a side where the divided pieces 110a and 110b first contact, if this misalignment G is prevented on the mating surface 118a side, it is possible to prevent the misalignment on the mating surface 118b side. It will be possible.

2A shows the vicinity of the mating surfaces 24a and 24b before bolt tightening, and FIG. 2B shows the state of the mating surfaces 24a and 24b after bolt tightening.
According to the present embodiment, the mating surfaces 24a and 24b are formed as planes inclined with respect to the plane C passing through the center O and the mating surfaces 24a and 24b. Misalignment can be reduced. Therefore, when the journal cap 14 is fastened and fixed to the fixing portion 12 with a bolt or the like, the displacement of the mating surfaces 24a and 24b can be reduced. Further, the displacement of the mating surfaces 24a and 24b after tightening and fixing can be eliminated by the tightening force applied at the time of tightening and fixing.

Further, when the needle bearing 15 is accommodated in the holding surface 13, the divided piece 16 a first comes into contact with the divided piece 16 b on the side where the divided piece 16 a enters the concave surface 12 a side. In this case, the mating surfaces 24a, so has an inclined surface that tip 16a ₁ is tilted to the outer peripheral side of the split pieces 16a, when tightening the journal cap 14 to the fixing portion 12 of the cylinder block, mating surface tip is the 16a ₁ Since it is directed outward by 24a, the shift | offset | difference in the mating surface 24a can be decreased. Thereby, the gap between the divided pieces 16a and 16b can be reduced even on the mating surface 24b. Then, the displacement of the mating surfaces 24a and 24b after tightening and fixing can be eliminated by the tightening force applied at the time of bolting and fixing.

  Accordingly, since no partial friction force is generated in the components of the needle bearing 15, local overwear does not occur. Therefore, damage to the components of the bearing device 10 can be prevented and durability can be improved. Further, since the mating surfaces 24a and 24b are inclined planes, the processing is easy and can be performed at low cost.

  Further, since the mating surfaces 24a and 24b are flat, they can be divided into divided pieces 16a and 16b by natural split processing from a cylindrical outer race material. The natural grooving process creates fine irregularities along the crystal grains generated on the divided surfaces, which facilitates the positioning of both divided pieces when assembling the bearing device, and allows the misalignment of the mating surfaces to be displaced. Can be suppressed. Furthermore, since the mating surfaces 24a and 24b are formed so as to be parallel to each other, there is an advantage that machine splitting or natural splitting is facilitated.

(Embodiment 2)
Next, a second embodiment of the device of the present invention will be described with reference to FIG. In the bearing device 10 of the present embodiment, the mating surfaces 30a and 30b of the two semi-cylindrical divided pieces 16a and 16b are positioned on the horizontal plane H. In other words, the mating surfaces 30a and 30b are arranged on the same plane as the contact surfaces 22a and 22b of the fixed portion 12 and the journal cap 14, and the mating surfaces 30a and 30b are in a square shape with respect to the center O of the journal portion 100a. The flat inclined surface arrange | positioned symmetrically in the direction which forms is formed. Other configurations are the same as those of the first embodiment.

  In the present embodiment, when the bearing device 10 is assembled to the cylinder block, both ends of the divided pieces 16a and 16b are simultaneously in contact with each other. And since the mating surfaces 30a and 30b are inclined with respect to the pinching force caused by the shape change of the concave surfaces 12a and 14a occurring in the horizontal direction, the mating surfaces of both the split pieces 16a and 16b are easily fitted to each other. Misalignment at the time of matching can be reduced. Therefore, when the journal cap 14 is fastened and fixed to the fixing portion 12 with a bolt or the like, the misalignment of both mating surfaces after the fastening can be eliminated by the fastening force applied at the time of fastening.

  For this reason, there is no deviation between the mating surfaces 30a and 30b, and no excessive friction occurs in the components of the needle bearing 15. Therefore, damage to the components of the needle bearing 15 can be prevented and its durability can be improved. Further, the mating surfaces 24a and 24b can be easily processed at a low cost.

  FIG. 4 is a modification of the second embodiment. In FIG. 4, in this modification, the mating surfaces 40 a and 40 b of the divided pieces 16 a and 16 b are located on the horizontal plane H as in the second embodiment. However, the mating surface forms a flat inclined surface that is symmetrically arranged in the direction of forming an inverted C shape with respect to the center O of the journal portion 100a. ing. Other configurations are the same as those of the second embodiment.

  In this modification, when the bearing device 10 is assembled to the cylinder block, both ends of the divided pieces 16a and 16b are simultaneously in contact with each other as in the second embodiment. And with respect to the pinching force that acts on the outer race 16 in the horizontal direction from the fixed portion 12 or the like, the occurrence of deviation can be reduced by the mating surfaces 40a and 40b inclined with the horizontal plane H. Therefore, there is no deviation in the mating surfaces 40a and 40b after being fastened and fixed to the fixing portion 12. Accordingly, since no excessive friction portion is generated in the component parts of the needle bearing 15, damage to the component parts of the needle bearing 15 can be prevented and durability can be improved. Moreover, the process of the mating surfaces 40a and 40b is also easy.

(Embodiment 3)
Next, a third embodiment of the device of the present invention will be described with reference to FIG. FIG. 5 is a perspective view of the outer race 16 of the bearing device 10. In the present embodiment, a cylindrical outer race material is divided into two semi-cylindrical divided pieces 16a and 16b by machine splitting. Then, the mating surfaces 50a and 50b of the split pieces 16a and 16b are arranged on a horizontal plane H passing through the center O of the journal portion 100a, and the mating surfaces 50a and 50b are arranged in the direction of the letter C with respect to the center O. ing. Further, along the direction of the axis A of the mating surfaces 50a and 50b, a chevron concave surface 52a is provided on the mating surface of the split piece 16a, and a chevron convex surface 52b is provided on the mating surface of the split piece 16b.

  In the present embodiment, the same operational effects as those of the first and second embodiments can be obtained, and in addition to this, by providing the chevron uneven surfaces 52a and 52b on the mating surfaces 50a and 50b, When the divided pieces 16a and the divided pieces 16b are brought into contact with each other for positioning, positioning in the direction of the axis A is easier than when natural split machining is performed.

  FIG. 6 shows a modification of the third embodiment. In FIG. 6, in this modification, two semi-cylindrical divided pieces 16a and 16b are divided by machine splitting as in the third embodiment. The mating surfaces 60a and 60b of the divided pieces 16a and 16b are arranged on a horizontal plane H passing through the center O of the journal portion 100a and arranged in the direction of the inverted C shape with respect to the center O. Further, along the direction of the axis A on the mating surfaces 60a and 60b, a stepped concave surface 62a is provided on the mating surface of the split piece 16a, and a stepped convex surface 62b is provided on the mating surface of the split piece 16b.

In this modification, the same effects as those of the first embodiment and the second embodiment can be obtained, and in addition, stepped irregularities with respect to the direction of the axis A on the mating surfaces 60a and 60b. The provision of the surfaces 62a and 62b has an advantage that the positioning in the direction of the axis A is easier when the split pieces 16a and 62b are brought into contact with each other and positioned than when natural split processing is performed.
5 and 6, the mating surfaces 50a and 50b or the mating surfaces 60a and 60b are arranged on the horizontal plane H. However, as in the first embodiment, the angle in the circumferential direction with respect to the horizontal plane H. They may be shifted by α.
In addition to the irregular surface of the above shape, an arc shape or other irregularities may be provided along the axis A on the mating surface.

(Embodiment 4)
Next, a fourth embodiment of the device of the present invention will be described with reference to FIG. In the present embodiment, a cylindrical outer race material is divided into two divided pieces 16a and 16b by natural split processing. As in the third embodiment shown in FIG. 5, the mating surfaces 70a and 70b of the split pieces 16a and 16b are arranged on a horizontal plane H passing through the center O of the journal portion 100a, and the mating surfaces 70a and 70b are centered. It is arranged in the direction of the letter C with respect to O.

  Knock pin insertion holes 72a and 72b are formed at positions where the mating surfaces 70a and 70b of the split pieces 16a and 16b face each other. When the bearing device is assembled into the cylinder block, the knock pin 74 is press-fitted into the knock pin insertion holes 72a and 72b, and the divided pieces 16a and 16b are aligned. As a result, the division pieces 16a and 16b can be easily positioned and the positional displacement between them can be prevented.

  According to the present invention, when a two-part rolling bearing is used as a crankshaft bearing of an internal combustion engine, uneven wear of the bearing components is eliminated, damage to the components is prevented, and durability of the bearing is improved. it can.

DESCRIPTION OF SYMBOLS 10 Needle type crankshaft bearing apparatus 12,104 Cylinder block fixing | fixed part 12a, 14a, 104a, 106a Concave surface 13 Holding surface 14,106 Journal cap (cap member)
15, 108 Needle bearing 16, 110, 120 Outer race 16a, 16b, 110a, 110b, 120a, 120b Split piece 18, 114 Cage 18a, 18b, 114a, 114b Separation piece 20, 112 Roller (needle)
22a, 22b, 117a, 117b contact surface 24a, 24b, 30a, 30b, 40a, 40b, 50a, 50b, 60a, 60b, 70a, 70b, 118a, 118b, 122 mating surface 52a chevron concave 52b chevron convex 62a step concave 62b Stepped convex surface 72a, 72b Knock pin insertion hole 74 Knock pin 100 Crank shaft 100a Journal portion 102 Cylinder block 116 Bolt A Axis C plane H Horizontal plane O Journal portion center G Deviation

Claims (6)

The crankshaft of an internal combustion engine is supported by a split type rolling bearing, and the split type rolling bearing is fitted and fixed to a cylindrical holding surface formed by combining a semicylindrical concave surface formed on each of a cylinder block and a cap member. In the crankshaft bearing device,
The outer race constituting the split type rolling bearing is constituted by two semi-cylindrical divided pieces, and the mating surface of the semi-cylindrical divided pieces is inclined with respect to a plane including the axial center line of the outer race. A bearing device for a crankshaft characterized by comprising: The mating surfaces of the two semi-cylindrical divided pieces are arranged differently in the circumferential direction of the crankshaft with respect to the contact surface where the cylinder block and the cap member are in contact,
The semi-cylindrical divided piece accommodated in the semi-cylindrical concave surface of the cap member faces the mating surface on the side entering the cylinder block side, and the tip of the one semi-cylindrical divided piece faces the cylinder block side. 2. The crankshaft bearing device according to claim 1, wherein the crankshaft bearing device is formed so as to be inclined toward the outer peripheral side.   The mating surfaces of the two semi-cylindrical divided pieces are arranged on the same plane as the contact surface where the cylinder block and the cap member are in contact, and the mating surfaces are symmetrical with respect to the axial center line of the outer race. The crankshaft bearing device according to claim 1, wherein the crankshaft bearing device is arranged in a square shape or a reverse square shape.   The crankshaft according to any one of claims 1 to 3, wherein irregularities are formed along the axial center line direction of the outer race on the mating surfaces of the two semi-cylindrical divided pieces. Bearing device.   The crankshaft bearing device according to any one of claims 1 to 3, wherein the two semi-cylindrical divided pieces are divided and formed from a cylindrical outer race material by natural split processing.   A knock pin insertion hole is drilled at a position where the two semi-cylindrical divided pieces face each other, and a knock pin is attached to the knock pin insertion hole, and the axial positioning of both divided pieces is performed by the knock pin. The bearing device for a crankshaft according to claim 5, wherein the bearing device is a crankshaft.

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