JP2008057741A - Camshaft support structure and internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a camshaft support structure and an internal combustion engine capable of simplifying assembly work by preventing dropping off of bearing parts in the process of assembly. <P>SOLUTION: The camshaft support structure comprises a camshaft 19, a cylinder head 13 and a bearing cap 13c for receiving the camshaft 19, and a needle roller bearing 21 as a bearing for rotatably supporting the camshaft 19. The needle roller bearing 21 includes an outer ring formed by continuously connecting circular arc-shaped outer ring members 22a, 22b in the circumferential direction and needle rollers 23 as rollers arranged along an inner diameter surface of the outer ring. Each of the outer ring members 22a, 22b has engagement claws 22c projecting radially outwardly from axial ends. A convex part and a concave part for receiving the convex part so as to prevent the outer ring member 22a, 22b from dropping off from the housing are formed on wall surfaces of the engagement claw 22c and the housing facing each other. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to internal combustion engines for automobiles and motorcycles, and camshaft support structures employed in these internal combustion engines.

A camshaft support structure employed in conventional automobile and motorcycle internal combustion engines is described in, for example, Japanese Patent Application Laid-Open No. 2005-90696 (Patent Document 1). Referring to FIG. 18, the camshaft support structure described in the publication includes a cam lobe 101a, a cylindrical journal portion 101b supported by a roller bearing 102, and a camshaft 101 having a large end portion 101c. A cylinder head 108 and a cap 109, a plurality of rollers 103, substantially semi-cylindrical holders 104 and 105, and substantially semi-cylindrical race plates 106 and 107, and a camshaft 101 And a roller bearing 102 rotatably supported with respect to the housing.
Japanese Patent Laid-Open No. 2005-90696

  As a method for assembling the camshaft support structure having the above-described structure, the race plate 106, the holding body 104 in which the rollers 103 are previously incorporated, the camshaft 101, the holding body 103, the race board 107, and the cap 109 are stacked in this order on the cylinder head 108. Finally, a general method is to fix the cylinder head 108 and the cap 109 with bolts or the like.

  Here, since the lace plates 106 and 107 and the holding bodies 104 and 105 are not fixed anywhere in the middle of the assembly, the assembly process has to be performed again if their positions are shifted or dropped. This problem is particularly noticeable in a camshaft support structure for an engine having a large number of cylinders.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a camshaft support structure and an internal combustion engine in which bearing parts are prevented from falling off during assembly and the assembly work is simplified.

  The camshaft support structure according to the present invention includes a camshaft, a housing that houses the camshaft, and a roller bearing that rotatably supports the camshaft with respect to the housing. Paying attention to the roller bearing, the outer ring member includes an outer ring formed by connecting a plurality of arc-shaped outer ring members in the circumferential direction, and a plurality of rollers arranged along the inner diameter surface of the outer ring. It has an engaging claw that protrudes radially outward and engages with the housing. Further, a convex portion and a concave portion that receives the convex portion and prevents the outer ring member from falling off from the housing are formed on the wall surfaces of the engaging claw and the housing facing each other.

  In the camshaft support structure having the above configuration, for example, the assembling work is performed in a state where the outer ring member is locked in advance so as not to fall off the housing by connecting the convex portion of the housing and the concave portion of the engaging claw. be able to. If the engaging claw is configured to be elastically deformable, it can be engaged with an elastic force, so that the adhesion is improved. As a result, it is possible to solve the problem that the bearing parts fall off during the assembly operation, and thus a camshaft support structure that simplifies the assembly operation can be obtained.

  Preferably, the convex portion and the concave portion are located on an imaginary line extending in the direction of the maximum load applied to the roller bearing from the camshaft. The degree of adhesion between the outer ring member and the housing is highest at the position where the convex portion and the concave portion are combined. Therefore, this roller bearing can support the largest load at this position (position where the convex portion and the concave portion are combined). Therefore, by arranging this position in a region where the largest load is applied, a camshaft support structure with excellent durability can be obtained.

  More preferably, the outer ring member further has a flange portion protruding radially inward from the axial end portion. And an engaging claw and a collar part are located on the same plane orthogonal to the rotating shaft line of a roller bearing. By setting it as the said structure, while being able to suppress the enlargement of an outer ring member, the rigidity of an engaging claw and a collar part improves.

  An internal combustion engine according to the present invention includes a housing, a cylinder provided in the housing, a valve for opening and closing an intake passage and an exhaust passage communicating with the cylinder, a camshaft for controlling timing of opening and closing the valve, and a camshaft. And a roller bearing that is rotatably supported. Paying attention to the roller bearing, the outer ring member includes an outer ring formed by connecting a plurality of arc-shaped outer ring members in the circumferential direction, and a plurality of rollers arranged along the inner diameter surface of the outer ring. An engaging claw that protrudes radially outward and engages with the housing is provided. Further, a convex portion and a concave portion that receives the convex portion and prevents the outer ring member from falling off from the housing are formed on the wall surfaces of the engaging claw and the housing facing each other.

  By adopting the camshaft support structure having the above-described configuration, an internal combustion engine in which assembly work is simplified can be obtained.

  According to the present invention, the assembling work can be performed in a state where the outer ring member is locked in advance so as not to drop out of the housing. Therefore, the camshaft support structure and the internal combustion engine that simplify the assembling work can be obtained.

  An internal combustion engine 11 according to an embodiment of the present invention will be described with reference to FIGS. 13 is a cross-sectional view showing one of the cylinders of the internal combustion engine 11 according to one embodiment of the present invention, FIG. 14 is a view showing a crankshaft 15 used in the internal combustion engine 11, and FIG. It is a figure which shows the camshaft 19 used.

  First, referring to FIG. 13, the internal combustion engine 11 performs a cylinder block 12 and a cylinder head 13 as a housing, a motion conversion mechanism that converts reciprocating motion into rotational motion, and intake of air-fuel mixture and exhaust of combustion gas. A reciprocating engine including an air supply / exhaust mechanism and a spark plug 20 as an ignition device.

  The motion conversion mechanism is housed in the cylinder block 12 and reciprocates in the cylinder 12a provided in the cylinder block 12, and a transmission (not shown) via a flywheel (not shown) and a clutch (not shown). And a connecting rod 16 having one end connected to the piston 14 and the other end connected to the crankshaft 15 for converting the reciprocating motion of the piston 14 into the rotational motion of the crankshaft 15.

  The air supply / exhaust mechanism is formed in the cylinder head 13 and communicates with the cylinder 12a, the intake passage 13a and the exhaust passage 13b, the intake valve 17 as a valve disposed between the cylinder 12a and the intake passage 13a, the cylinder 12a and the exhaust passage. An exhaust valve 18 as a valve disposed between the passages 13b, and an intake valve 17 and a camshaft 19 for controlling the opening / closing timing of the exhaust valve 18 are provided.

  The intake valve 17 includes a valve stem 17a, a valve head 17b provided at one end of the valve stem 17a, and a valve spring 17c that urges the intake valve 17 in a direction to close the intake passage 13a. A camshaft 19 is connected to the other end portion of the stem 17a. The exhaust valve 18 has the same configuration as the intake valve 17 and will not be described.

  Referring to FIG. 14, a crankshaft 15 used in the internal combustion engine 11 includes a shaft portion 15a, a crank arm 15b, and a crank pin 15c for disposing a connecting rod 16 between adjacent crank arms 15b. . The crankshaft 15 is rotatably supported by a needle roller bearing 21 according to an embodiment of the present invention described later. Further, the same number of crank pins 15c as the number of cylinders of the internal combustion engine 11 are provided.

  Referring to FIG. 15, cam shaft 19 used in internal combustion engine 11 includes a shaft portion 19a and a plurality of cams 19b. The shaft portion 19a is rotatably supported by a needle roller bearing 21 according to an embodiment of the present invention described later. The camshaft 19 is connected to the crankshaft 15 by a timing belt (not shown), and rotates as the crankshaft 15 rotates.

  Since the cam 19b is connected to the intake valve 17 or the exhaust valve 18, respectively, the same number as the valves 17 and 18 is provided. Further, as shown in FIG. 13, the cam 19b includes a long diameter portion 19c having a relatively large diameter and a short diameter portion 19d having a relatively small diameter, and the plurality of cams 19b are formed as shown in FIG. The position of the long diameter portion 19c is shifted in the circumferential direction. This makes it possible to open and close the valves 17 and 18 connected to the plurality of cams 19b at different timings.

  The internal combustion engine 11 is a DOHC (Double Over Head Camshaft) engine in which the camshaft 19 is disposed on the upper side of the cylinder head 13 and provided on the intake valve 17 side and the exhaust valve 18 side, respectively.

  Next, the operating principle of this internal combustion engine will be described.

  First, in the internal combustion engine 11, if the process of moving the piston 14 between the position where the piston 14 is most elevated (top dead center) and the position where the piston 14 is most lowered (bottom dead center) is defined as one process, This is a four-cycle engine comprising four steps of a compression step, a combustion step, and an exhaust step.

  In the intake process, the piston 14 moves from the top dead center to the bottom dead center with the intake valve 17 open and the exhaust valve 18 closed. As a result, the volume inside the cylinder 12a (referring to the space above the piston 14, hereinafter the same) increases and the internal pressure decreases, so the air-fuel mixture flows from the intake passage 13a into the cylinder 12a. The air-fuel mixture refers to a mixture of air (oxygen) and gasoline in a mist form.

  In the compression process, the piston 14 moves from the bottom dead center to the top dead center with the intake valve 17 and the exhaust valve 18 closed. As a result, the internal volume of the cylinder 12a decreases and the internal pressure increases.

  In the combustion process, the spark plug 20 is ignited with the intake valve 17 and the exhaust valve 18 closed. As a result, the air-fuel mixture in the compressed state expands abruptly by burning, and pushes down the piston 14 from the top dead center to the bottom dead center. By transmitting this force to the crankshaft 15 through the connecting rod 16 as a rotational motion, a driving force is generated.

  In the exhaust process, the piston 14 moves from the bottom dead center to the top dead center with the intake valve 17 closed and the exhaust valve 18 opened. As a result, the volume inside the cylinder 12a is reduced and the combustion gas flows out to the exhaust passage 13b. In this process, after the piston 14 reaches the top dead center, the process returns to the intake process.

  In each of the above steps, “the state in which the intake valve 17 is open” means that the long diameter portion 19c of the cam 19b is in contact with the intake valve 17 and the intake valve 17 is pushed downward against the valve spring 17c. The state where the intake valve 17 is closed is a state in which the short diameter portion 19d of the cam 19b is in contact with the intake valve 17 and the intake valve 17 is pushed upward by the restoring force of the valve spring 17c. Point to. Further, since the same applies to the exhaust valve 18, the description thereof is omitted.

  In each of the above processes, the driving force is generated only in the combustion process, and in the other processes, the piston 14 reciprocates by the driving force generated in the other cylinders. Therefore, from the viewpoint of maintaining smooth rotation of the crankshaft 15, it is desirable to shift the timing of the combustion stroke with a plurality of cylinders.

  With reference to FIGS. 1-9, the needle roller bearing 21 as a roller bearing which concerns on one Embodiment of this invention, and the camshaft support structure using this needle roller bearing 21 are demonstrated. 1 and FIGS. 7 to 9 are views showing states before and after the camshaft support structure according to the embodiment of the present invention is assembled, and FIGS. 2 to 6 are needle roller bearings according to the embodiment of the present invention. It is a figure which shows each component of 21.

  First, referring to FIG. 1, a camshaft support structure according to an embodiment of the present invention includes a camshaft 19, a cylinder head 13 and a bearing cap 13 c as a housing for housing the camshaft 19, and the camshaft 19. And a needle roller bearing 21 that rotatably supports the housing.

  The needle roller bearing 21 includes an outer ring 22 formed by connecting a plurality of arc-shaped outer ring members 22 a and 22 b in the circumferential direction, and a needle roller 23 as a plurality of rollers disposed along the inner diameter surface of the outer ring 22. And a cage 24 having a parting line extending in the axial direction of the bearing at one place on the circumference and holding the intervals between the plurality of needle rollers 23.

  As a bearing for supporting the camshaft 19, a needle roller bearing 21 is generally employed. The needle roller bearing 21 has an advantage that a high load capacity and high rigidity can be obtained for a small bearing projection area because the needle roller 23 and the raceway surface are in line contact. Therefore, it is preferable in that the thickness dimension in the radial direction of the support portion can be reduced while maintaining the load capacity.

  The outer ring member 22a will be described with reference to FIGS. 2 is a side view of the outer ring member 22a, FIG. 3 is a view of FIG. 2 viewed from the III direction, and FIG. 4 is a view of FIG. 2 viewed from the IV direction. Further, since the outer ring member 22b has the same shape as the outer ring member 22a, description thereof is omitted.

  First, referring to FIG. 2, the outer ring member 22 a has a semicircular shape with a central angle of 180 °, and an engaging claw 22 c and a flange portion 22 d are formed at both ends in the axial direction. The two outer ring members 22a and 22b are connected in the circumferential direction to form an annular outer ring 22. The central portion in the axial direction of the inner diameter surface of the outer ring 22 functions as a raceway surface of the needle rollers 23.

  The engaging claws 22c protrude radially outward from both axial end portions of the circumferential central portion, and engage with the housing when assembled to prevent the outer ring member 22a from rotating. Further, a locking means 22i for preventing the outer ring member 22a from falling off the housing is provided on the wall surface of the engaging claw 22c facing in the axial direction.

  The flange portion 22d protrudes radially inward from the end portion in the axial direction over substantially the entire area of the outer ring member 22a in the circumferential direction except for the portion where the engagement claw 22c is provided. The flange 22d restricts the movement of the cage 24 in the axial direction and improves the retention of the lubricating oil inside the bearing. The engaging claw 22c and the flange portion 22d are arranged on the same plane orthogonal to the rotational axis of the needle roller bearing 21. Thereby, the enlargement of the outer ring member 22a can be suppressed, and the rigidity of the engaging claws 22c and the flange portion 22d is improved.

  Referring to FIG. 3, a substantially V-shaped concave portion 22e having a central portion in the axial direction recessed in the circumferential direction is formed at one end portion in the circumferential direction of the outer ring member 22a. Referring to FIG. 4, the other end of the outer ring member 22a in the circumferential direction has two flat portions 22f at both ends in the axial direction and a circular tip between the two flat portions 22f. A substantially V-shaped convex portion 22g protruding in the direction is provided. The concave portion 22e receives the convex portion 22g of the adjacent outer ring member when the outer ring members 22a and 22b are connected in the circumferential direction. Thus, by making the shape of the abutting portion substantially V-shaped, the needle rollers 23 can rotate smoothly. In addition, the shape of the abutting part of the outer ring members 22a and 22b is not limited to a substantially V shape, and may be any shape that allows the needle rollers 23 to rotate smoothly, for example, a substantially W shape.

  3 and 4, the outer ring member 22a is provided with an oil hole 22h penetrating from the outer diameter side to the inner diameter side. The oil hole 22h is provided at a position facing an oil passage (not shown) provided in the housing, and supplies lubricating oil into the needle roller bearing 21. Note that the size, position, and number of the oil holes 22h depend on the size, position, and number of oil passages provided in the housing.

  Next, the cage 24 will be described with reference to FIGS. 5 and 6. 5 is a side view of the cage 24, and FIG. 6 is a partial cross-sectional view including a divided portion of the cage 24. Referring to FIGS. 5 and 6, the retainer 24 has a substantially C shape having a parting line extending in the axial direction of the bearing at one place on the circumference, and a pocket 24 c that accommodates the needle rollers 23. It is provided at equal intervals in the circumferential direction. The cage 24 is formed by injection molding of a resin material.

  The cut end surface 24a on one side in the circumferential direction of the divided portion is provided with a recess 24d, and the cut end surface 24b on the other side is provided with a protrusion 24e corresponding to the recess 24d, and the recess 24d and the protrusion 24e are engaged. By combining, an annular retainer 24 can be obtained. In this embodiment, the width of the tip portion of the convex portion 24e is set larger than that of the root portion, and the width of the opening portion of the concave portion 24d is set smaller than that of the innermost portion. Thereby, the engagement between the concave portion 24d and the convex portion 24e is ensured.

  Next, a procedure for incorporating the needle roller bearing 21 into the camshaft 19 will be described with reference to FIGS. 1 and 7 to 9.

  First, the needle rollers 23 are incorporated in the pockets 24 c of the cage 24. Next, using the elasticity of the cage 24, the divided portion is expanded and assembled into the camshaft 19. Further, the concave portion 24d and the convex portion 24e are engaged so that the retainer 24 does not come off.

  Next, the outer ring member 22 a is fitted into the inner peripheral surface of the cylinder head 13, and the engagement claw 22 c is engaged with the recess 13 d of the cylinder head 13. Further, the outer ring member 22a is prevented from dropping from the cylinder head 13 by the locking means 22i and 13e provided in the engaging claw 22c and the recess 13d, respectively. At this time, the oil hole 22h provided in the outer ring member 22a and the oil supply path (not shown) of the cylinder head 13 are assembled so as to face each other. The same operation is performed between the outer ring member 22b and the bearing cap 13c.

  With reference to FIG. 9, a specific structure of the locking means 22 i and 13 e provided on the outer ring member 22 a and the cylinder head 13 will be described. A protrusion 13e as a protrusion protruding from the bottom wall is formed in the recess 13d that receives the engaging claw 22c of the cylinder head 13. On the other hand, the outer ring member 22a is formed with a hole 22i as a recess penetrating the wall surface facing the axial direction of the engaging claw 22c. Then, the outer ring member 22a is fixed so as not to drop out of the bearing cap 13 by fitting the projection 13e into the hole 22i using the elasticity of the engaging claw 22c.

  Then, the camshaft 19 around which the cage 24 is wound is placed on the cylinder head 13 to which the outer ring member 22a is attached, and the bearing cap 13c to which the outer ring member 22b is attached is further placed thereon, The cylinder head 13 and the bearing cap 13c are fixed with bolts or the like.

  By adopting the above assembling procedure, the camshaft 19, the outer ring 22, the cage 24, and the housing are arranged concentrically, and the needle roller bearing 21 in which the needle roller 23 can rotate stably is obtained. be able to. Further, the needle roller bearing 21 having the above configuration is incorporated from the radial direction of the support portion by dividing the outer ring 22 into two outer ring members 22a and 22b and dividing the cage 24 at one place in the circumferential direction. Therefore, it can be employed as a bearing for supporting the camshaft 19.

  Further, since the outer ring members 22a and 22b are locked in advance in the housing and the retainer 24 is wound around the camshaft 19 and fixed, the assembly work can be performed, so that the bearing parts fall off during the assembly work. Disappears. As a result, the assembling work of the camshaft support structure can be simplified. Further, since the engaging claw 22c having the above configuration is elastically deformed with the bent portion as a base point, the protrusion 13e can be easily fitted into the hole 22i.

Furthermore, the outer ring member 22a, 22b is, the hole 22i is incorporated so as to be located on the imaginary line l ₁ extending in the direction of the maximum load applied against the needle roller bearing 21 from the camshaft 19. In the camshaft support structure configured as described above, the degree of adhesion between the outer ring members 22a and 22b and the housings 13 and 13e is highest at the position where the projection 13e and the hole 22i are combined. Therefore, the camshaft support structure can support the largest load at this position (position of the protrusion 13e and the hole 22i). Therefore, by arranging this position in a region where the largest load is applied, a camshaft support structure with excellent durability can be obtained.

  In the internal combustion engine 11 shown in FIG. 13, the maximum load applied from the camshaft 19 to the needle roller bearing 21 is the reaction of the force that pushes the valves 17 and 18 downward against the valve springs 17c and 18c. The direction is the direction opposite to the direction in which the camshaft 19 pushes the valves 17 and 18 (the direction of the arrow in FIG. 13).

Moreover, even without a projection 13e and the hole 22i is positioned on exactly the virtual line l ₁ it has the advantages of the present invention. For example, if the engagement claw 22c having the hole 22i is positioned on the virtual line l1, the effect of the present invention can be sufficiently obtained.

  In addition, the cage 24 in the above embodiment is an example of a resin cage having high production efficiency and high elastic deformability. However, the cage is not limited to this and may be a machined cage by cutting. Alternatively, it may be a press cage obtained by pressing a steel plate.

  Moreover, although the collar part 22d in said embodiment showed the example provided in the whole area of the circumferential direction of outer ring member 22a, 22b except the part by which the engagement nail | claw 22c is arrange | positioned, it does not restrict to this, It may be partially provided in a part of the circumferential direction. At that time, the location and number of the buttocks can be arbitrarily set, but it is desirable that they are arranged in the non-load region when incorporated in the camshaft 19.

  Moreover, in said embodiment, the example of the protrusion 22e provided in the housing and the hole 22i provided in outer ring member 22a, 22b as a latching means provided between the outer ring members 22a, 22b and a housing. However, the present invention is not limited to this, and any structure that can prevent the outer ring members 22a and 22b from falling off the housing can be employed. For example, as a modification of the embodiment shown in FIG. 9, a bolt is inserted into the hole 22i of the engaging claw 22c to form a convex portion, and a bolt hole for receiving the bolt is formed in the bottom wall of the concave portion 13d of the bearing cap 13c. The member 22b and the bearing cap 13c may be fixed.

  With reference to FIG. 10 and FIG. 11, an example of a locking means according to another embodiment of the present invention will be described. Since the basic configuration is the same as that of the camshaft support structure shown in FIGS. 1 to 9, the description of the common points is omitted, and the difference will be mainly described.

  First, referring to FIG. 10, the outer ring member 32b is formed with a hole 32i as a recess penetrating the wall surface facing the axial direction of the engaging claw 32c, and the bottom wall of the recess 33d of the bearing cap 33c is formed on the bottom wall. , A projection 33e that fits into the hole 32i is formed. Note that the protrusion height of the protrusion 13e is gradually increased in the insertion direction of the engagement claw 32c (upward direction in FIG. 10), and the insertion of the engagement claw 32c is easy. After fitting into 32i, the structure is difficult to come off.

  Next, referring to FIG. 11, the outer ring member 42b is formed with a protrusion 42i as a protrusion protruding from the wall surface facing the axial direction of the engaging claw 42c, and the bottom wall of the recess 43d of the bearing cap 43c. Is formed with a recess 43e for receiving the protrusion 42i. By fitting the projection 42i into the recess 43e, the outer ring member 42b can be prevented from falling off from the bearing cap 43c.

  In any of the embodiments shown in FIGS. 9 to 11, the outer ring member can be fixed to the housing with one touch because the convex portion is merely fitted into the concave portion. As a result, it is possible to obtain a camshaft support structure and an internal combustion engine that are excellent in assemblability.

  In the above embodiment, an example in which the needle roller bearing 21 is employed as a bearing for supporting the camshaft 19 has been shown. However, the present invention is also applicable to other roller bearings such as a cylindrical roller bearing and a rod roller bearing. can do.

  Further, the needle roller bearing 21 in the above embodiment is not only a bearing that supports the camshaft 19, but also a bearing that supports the shaft portion 15a of the crankshaft 15, the rocker shaft, and the like as shown in FIG. It can be used widely.

  Further, the present invention can be applied to a single-cylinder internal combustion engine, but the shaft portion 15a of the crankshaft 15 employed in a multi-cylinder engine as shown in FIG. 14 or a camshaft 19 as shown in FIG. It is suitable as a bearing for supporting a portion where the needle roller bearing 21 cannot be inserted from the axial direction, such as the shaft portion 19b.

  Next, a method for manufacturing the outer ring member 22a according to one embodiment of the present invention will be described with reference to FIG. FIG. 12 is a diagram showing a part of the manufacturing process of the outer ring member 22a. Moreover, since the manufacturing method of the outer ring member 22b is the same as that of the outer ring member 22a, description thereof is omitted.

  First, carbon steel having a carbon content of 0.15 wt% or more and 1.1 wt% or less is used as a starting material. Specifically, SCM415 or S50C having a carbon content of 0.15 wt% or more and 0.5 wt% or less, or SAE1070 or SK5 having a carbon content of 0.5 wt% or more and 1.1 wt% or less is considered. It is done.

  Carbon steel having a carbon content of less than 0.15 wt% is difficult to form a carburized hardened layer by quenching, and needs to be carbonitrided to obtain the required hardness for the outer ring member 22a. The carbonitriding process increases the equipment cost compared to each quenching process described later, and as a result, the manufacturing cost of the needle roller bearing 21 increases. In addition, in carbon steel having a carbon content of less than 0.15 wt%, a sufficient carburized and hardened layer may not be obtained even by carbonitriding, and surface-origin-type peeling may occur at an early stage on the raceway surface. On the other hand, since carbon steel having a carbon content exceeding 1.1 wt% is remarkably deteriorated in workability, the processing accuracy is lowered, and the production cost is increased due to an increase in the number of processing steps.

  Referring to FIG. 12, as a first step, the outer shape of outer ring member 22a is formed by punching a steel plate (step a). Moreover, the part used as the recessed part 22e is formed in the one side edge part of a longitudinal direction, and the flat part 22f and the convex part 22g are formed in the other side edge part. Cuts that are divided into engagement claws 22c and flanges 22d are formed at both ends in the short direction, and a hole 22i is formed as a locking means between the two cuts. Furthermore, the oil hole 22h may be processed simultaneously with the formation of the outer shape.

  At this time, the length in the longitudinal direction of the outer ring member 22a is determined based on the diameter of the camshaft 19, and the length in the short direction is determined based on the roller length of the needle roller 23 to be used. However, since the short direction includes portions that become the engaging claws 22c and the flange portion 22d, the length in the short direction in this step is longer than the axial width dimension of the finished product of the outer ring member 22a. Become.

  In this step, all the parts may be punched by a single punching process, or a predetermined shape may be obtained by repeating the punching process a plurality of times. In addition, when using a progressive press, it is good to form the pilot hole 25 for determining the processing position of each processing process, and to provide the connection part 26 between adjacent outer ring members. In this embodiment, the connecting portion 26 is provided outside the portion that becomes the engaging claw 22c.

  The second step includes a step of bending the outer shape of the outer ring member 22a to a predetermined curvature by bending, and a step of forming the flange portion 22d protruding radially inward from both axial end portions of the outer ring member 22a ( b process-f process). Specifically, bending is performed sequentially from both ends in the longitudinal direction, leaving the central portion including the connecting portion 26 (steps b and c). Next, about the both ends of the longitudinal direction which gave the bending process, a bending process is given to the both ends of a transversal direction, and the collar part 22d is formed (d process). Next, a bending process is also performed on the central portion in the longitudinal direction so that the outer shape of the outer ring member 22a has a predetermined curvature (step e). Finally, the connecting portion 26 is removed, and the engagement claw 22c is bent outward in the radial direction. (Step f).

  After the press working step is completed, heat treatment is performed to obtain predetermined mechanical properties such as hardness required for the outer ring member 22a. In addition, the surface hardness Hv of the inner diameter surface of the outer ring member 22a that functions as a raceway ring needs to be 635 or more.

  In order for the outer ring member 22a to obtain a hardened layer having a sufficient depth, it is necessary to select an appropriate heat treatment method depending on the carbon content of the starting material. Specifically, in the case of a material having a carbon content of 0.15 wt% or more and 0.5 wt% or less, carburizing and quenching treatment is performed, and for a material having a carbon content of 0.5 wt% or more and 1.1 wt% or less. In some cases, bright quenching or induction quenching is performed.

  The carburizing and quenching process is a heat treatment method utilizing the phenomenon that carbon dissolves in high-temperature steel, and a surface layer (carburized hardened layer) with a large amount of carbon can be obtained while the amount of carbon in the steel is low. . Thereby, the surface is hard, the inside is soft, and the property with high toughness is obtained. Moreover, the equipment cost is low compared with the carbonitriding equipment.

  The bright quenching process refers to a quenching process performed while preventing oxidation of the steel surface by heating in a protective atmosphere or vacuum. In addition, the equipment cost is low compared with carbonitriding equipment and carburizing and quenching equipment.

  Induction hardening is a method of making a hardened hardened layer by rapidly heating and rapidly cooling the steel surface using the principle of induction heating. Compared to other quenching treatment facilities, there is a merit that the equipment cost is significantly lower and that the gas is not used in the heat treatment process, so that it is environmentally friendly. It is also advantageous in that a partial quenching process can be performed.

  Furthermore, it is desirable to perform tempering after the above-mentioned quenching treatment in order to reduce residual stress and internal strain caused by quenching and to improve toughness and stabilize dimensions.

  Further, a load is applied to the engaging claw 22 c that engages with the housing in the rotational direction of the needle roller bearing 21. In order to prevent the engagement claw 22c from being damaged by this load, it is effective to increase the toughness by making the hardness of the engagement claw 22c lower than that of other portions. The hardness Hv of the engaging claw 22c is desirably set in the range of 300 or more and 600 or less. When the hardness Hv is 600 or more, the engagement claw 22c may be damaged by a sudden load. On the other hand, if the hardness Hv is less than 300, the engaging claws 22c may be worn out early.

  As a specific method for increasing the toughness of the engaging claw 22c, partial annealing is performed only on the engaging claw 22c after the heat treatment step, or only on the engaging claw 22c before the heat treatment step. Carburizing treatment is effective. The partial annealing and the carburizing treatment may be performed on the entire area of the engaging claw 22c, but it is also effective when applied only to the root portion of the engaging claw 22c.

  Annealing is performed in order to soften the material hardened by the quenching process and increase toughness, and is performed by gradually cooling the material after heating to a predetermined temperature. In order to prevent the annealing effect from reaching the raceway surface of the outer ring member 22a, high-frequency annealing is suitable.

  The carburizing treatment is performed to prevent carbon from being dissolved in the material by carburizing and quenching treatment or the like, and refers to a treatment such as forming a film on the engaging claws 22c. Thereby, even when carburizing and quenching is performed, it is difficult to form a carburized layer on the portion of the engaging claw 22c where the coating is formed.

  In this embodiment, the example in which the step of forming the curvature of the outer shape of the outer ring member 22a and the step of forming the flange portion 22d are performed in parallel. However, the present invention is not limited thereto, and the curvature of the outer shape is not limited thereto. You may perform independently the process of forming, and the process of forming the collar part 22d.

  Moreover, said 1st process and 2nd process are examples of the manufacturing method of the outer ring | wheel member which concerns on this invention, Comprising: Each process may be further subdivided and it may also add a required process further. it can. The order of the processing steps can be arbitrarily changed.

  Furthermore, although each said process (a process-f process) may be performed by a single-function press as a separate process, respectively, it is good also as performing by a progressive press or a transfer press. Thereby, each process can be performed continuously. Moreover, productivity can be improved by using the manufacturing apparatus of the outer ring member 22a which has the process part equivalent to all or one part of said each process (a process-f process), and, as a result, needle roller The product price of the bearing 21 can be suppressed.

  In the present specification, “sequential press” refers to a method of continuously processing a material by having a plurality of processing steps in the press and moving the material by a feeder at a press inlet. Shall. In addition, in this specification, “transfer press” means that when a plurality of processing steps are required, the necessary number of stages for performing each step are provided, and processing is performed at each stage while moving the process product by the transfer device. Refers to the method of performing

  Next, a camshaft support structure according to another embodiment of the present invention will be described with reference to FIGS. 16 is a cross-sectional view taken along a plane orthogonal to the rotational axis of the camshaft support structure, and FIG. 17 is a cross-sectional view taken along line XVII-XVII in FIG. The basic structure of the camshaft support structure is the same as that of the camshaft support structure shown in FIGS. 7 and 8. Therefore, the description of the common points will be omitted, and the differences will be mainly described.

  Referring to FIG. 16, the camshaft support structure according to another embodiment of the present invention includes housings 53, 53 c, camshaft 59, and needle rollers that rotatably support camshaft 59 with respect to housing 53. The bearing 61 is provided. Since the needle roller bearing 61 has the same configuration as the needle roller bearing 21, a description thereof will be omitted.

  The housing includes a cylinder head 53 and a bearing cap 53c. A concave portion 53d for receiving the engaging claw 62c of the needle roller bearing 61 is provided on the inner diameter surface of the bearing cap 53c, and a relatively thick wall is provided at a position corresponding to the concave portion 53d on the outer diameter surface. A portion 53e is provided.

As described above, the concave portion 53d of the bearing cap 53c is located on the imaginary line l ₂ extending in the direction of the maximum load applied to the needle roller bearing 61 from the camshaft 59. Therefore, by providing the thick portion 53e at this position, it is possible to compensate for the decrease in rigidity of the bearing cap 53c due to the provision of the concave portion 53d.

  Further, referring to FIG. 17, the thick portion 53 e extends in the axial direction of the camshaft 59 and connects adjacent bearing caps 53 c to each other. As described above, the built-in property of the camshaft support structure is improved by using the thick portion 53e as a connecting member for connecting the adjacent bearing caps 53c. Further, the rigidity against the inclination of the camshaft 59 (vertical direction in FIG. 17) is improved.

  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 a camshaft support structure for supporting a camshaft of an automobile engine and an internal combustion engine.

It is a figure which shows the state before the assembly of the camshaft support structure which concerns on one Embodiment of this invention. It is a figure which shows the outer ring member of the roller bearing which concerns on one Embodiment of this invention. It is the figure seen from the III direction of FIG. It is the figure seen from the IV direction of FIG. It is a figure which shows the side view of the holder | retainer of the roller bearing which concerns on one Embodiment of this invention. It is a fragmentary sectional view containing the division | segmentation part of the holder | retainer of FIG. It is sectional drawing which looked at the state after the incorporation of the camshaft support structure of FIG. 1 from the axial direction. It is sectional drawing which looked at the state after the incorporation of the camshaft support structure of FIG. 1 from the radial direction. It is an enlarged view of the P section of FIG. It is a figure which shows other embodiment of FIG. It is a figure which shows other embodiment of FIG. It is a figure which shows a part of manufacturing process of the outer ring member which concerns on one Embodiment of this invention, Comprising: An upper stage is a top view and a lower stage is sectional drawing. It is sectional drawing which shows one cylinder of the internal combustion engine which concerns on one Embodiment of this invention. It is a figure which shows the crankshaft employ | adopted as the internal combustion engine of FIG. It is a figure which shows the camshaft employ | adopted as the internal combustion engine of FIG. It is a figure which shows the camshaft support structure which concerns on other embodiment of this invention. It is sectional drawing in XVII-XVII of FIG. It is a figure which shows the conventional camshaft support structure.

Explanation of symbols

  11 Internal combustion engine, 12 Cylinder block, 12a Cylinder, 13, 53c, 108 Cylinder head, 13a Inlet passage, 13b Exhaust passage, 13c, 33c, 43c, 53c Bearing cap, 13d, 33d, 43d, 53d Recessed portion, 13e, 33e, 43e Locking means, 14 piston, 15 crankshaft, 15a shaft, 15b crank arm, 15c crankpin, 16 connecting rod, 17, 18 valve, 17a, 18a valve stem, 17b, 18b valve head, 17c, 18c valve spring, 19, 59, 101 Camshaft, 19a Shaft, 19b Cam, 19c Long diameter part, 19d Short diameter part, 53e Thick part, 101a Cam lobe, 101b Journal part, 101c End large diameter part, 20 Spark plug, 2 1,61 Needle roller bearing, 22 outer ring, 22a, 22b, 32b, 42b outer ring member, 22c, 32c, 42c, 62c engaging claw, 22d collar, 22e, 24d concave, 22f flat, 22g, 24e convex , 22h Oil hole, 22i, 33i, 43i Locking means, 23 Needle roller, 24 Cage, 24a, 24b Cut end face, 24c Pocket, 102 Roller bearing, 103 Roller, 104, 105 Holder, 106, 107 Race plate 109 cap.

Claims (4)

A camshaft,
A housing that houses the camshaft;
A camshaft support structure comprising a roller bearing that rotatably supports the camshaft with respect to the housing,
The roller bearing includes an outer ring formed by connecting a plurality of arc-shaped outer ring members in a circumferential direction, and a plurality of rollers disposed along an inner diameter surface of the outer ring, and the outer ring member has an axial end. An engaging claw that protrudes radially outward from the portion and engages the housing;
A camshaft support structure in which a convex portion and a concave portion that receives the convex portion and prevents the outer ring member from falling off from the housing are formed on wall surfaces of the engaging claw and the housing facing each other.   The camshaft support structure according to claim 1, wherein the convex portion and the concave portion are located on an imaginary line extending in a direction of a maximum load applied from the camshaft to the roller bearing. The outer ring member further has a flange that protrudes radially inward from the axial end,
The camshaft support structure according to claim 1 or 2, wherein the engagement claw and the flange are located on the same plane perpendicular to the rotation axis of the roller bearing. A housing;
A cylinder provided in the housing;
A valve for opening and closing an intake passage and an exhaust passage communicating with the cylinder;
A camshaft for controlling the opening and closing timing of the valve;
An internal combustion engine comprising a roller bearing that rotatably supports the camshaft;
The roller bearing includes an outer ring formed by connecting a plurality of arc-shaped outer ring members in a circumferential direction, and a plurality of rollers disposed along an inner diameter surface of the outer ring, and the outer ring member has an axial end. An engaging claw that protrudes radially outward from the portion and engages the housing;
An internal combustion engine in which a convex portion and a concave portion that receives the convex portion and prevents the outer ring member from falling off from the housing are formed on wall surfaces of the engaging claw and the housing facing each other.

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