JP5106810B2 - Camshaft support structure and internal combustion engine - Google Patents

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. 12, 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.

The lace plates 106 and 107 having the above-described configuration are generally manufactured by pressing a steel plate such as a cold rolled steel plate (SPC). In addition, heat treatment is performed in order to obtain predetermined mechanical properties such as hardness, and an inner diameter surface that is a raceway surface of the roller 103 is ground so that the roller 103 can rotate smoothly.
JP-A-2005-90696

  In the camshaft support structure configured as described above, the camshaft 101 is subjected to a load that is biased in a predetermined direction during rotation. Therefore, a region where a relatively large load is applied in the circumferential direction (hereinafter referred to as “load region”). And a region where only a relatively small load is applied (hereinafter referred to as “non-load region”).

  Therefore, since a large load is applied to the lace plate disposed at a position including the load region, high machining accuracy is required to maintain smooth rotation of the rollers 103. On the other hand, the production of the race plate requires many steps as described above, and the production cost of the race plate occupies a large weight in the production cost of the entire roller bearing 102. This tendency is particularly noticeable when high-precision machining is required.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a highly reliable camshaft support structure and an internal combustion engine provided with such a camshaft support structure by adopting a roller bearing in which the rollers can rotate smoothly while suppressing manufacturing costs Is to provide.

  A 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 raceway surface, which is provided with an arc-shaped outer ring member and a plurality of rollers, is located on the radially outer side of the plurality of rollers. It is formed in the surface and the inner peripheral surface of the housing connected to the circumferential end of the outer ring member.

  Since a part of the raceway surface of the roller is used as the inner peripheral surface of the housing as in the above configuration, the number of parts of the roller bearing can be reduced, so that the manufacturing cost as a whole can be suppressed. As a result, a low-cost and highly reliable camshaft support structure can be obtained.

  Preferably, the outer ring member is disposed at a position including the load region of the camshaft. In particular, by arranging the outer ring member at a position including the load region of the camshaft, smooth rotation of the rollers can be maintained.

  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 raceway surface, which is provided with an arc-shaped outer ring member and a plurality of rollers, is located on the radially outer side of the plurality of rollers. It is formed in the surface and the inner peripheral surface of the housing connected to the circumferential end of the outer ring member.

  By adopting the camshaft support structure having the above configuration, a highly reliable internal combustion engine can be obtained.

  According to the present invention, the outer ring member is disposed only in the portion (load region) where high accuracy is required on the raceway surface of the roller, and the other portion is configured by the inner peripheral surface of the housing, thereby suppressing the manufacturing cost. , Can keep the rollers rotating smoothly. As a result, a highly reliable camshaft support structure and internal combustion engine can be obtained at low cost.

  An internal combustion engine 11 according to an embodiment of the present invention will be described with reference to FIGS. 9 is a sectional view showing one of the cylinders of the internal combustion engine 11 according to the embodiment of the present invention, FIG. 10 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. 9, 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 is connected to the cylinder 12a. 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. 10, 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. 11, 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. 9, 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 this internal combustion engine 11, when 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. 1-6, 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, 5, and 6 are views showing states before and after the camshaft support structure according to an embodiment of the present invention is assembled, and FIGS. 2 to 4 are needle rollers according to an embodiment of the present invention. FIG. 3 is a diagram showing each component of a bearing 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 has an arc-shaped outer ring member 22, needle rollers 23 as rollers, and a parting line extending in the axial direction of the bearing at one place on the circumference. And a retainer 24 that retains the interval.

  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.

  FIG. 2 is a side view of the outer ring member 22. Referring to FIG. 2, the outer ring member 22 has a semicircular shape with a central angle of 180 °, and protrudes radially inward from both axial end portions to restrict the movement of the cage 24 in the axial direction. 22a and an oil hole 22b penetrating from the outer diameter surface to the inner diameter surface. Further, the central portion in the axial direction of the inner diameter surface of the outer ring member 22 functions as a raceway surface of the needle rollers 23. The oil hole 22b 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. Further, the size, position, and number of the oil holes 22b 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. 3 and 4. 3 is a side view of the cage 24, and FIG. 4 is a partial cross-sectional view including a divided portion of the cage 24. As shown in FIG. The cage 24 has a substantially C shape having a dividing line extending in the axial direction of the bearing at one place on the circumference, and pockets 24c for accommodating the needle rollers 23 are provided at equal intervals in the circumferential direction. Yes. 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, 5, and 6.

  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 camshaft 19, the outer ring member 22, and the bearing cap 13c fixed by winding the cage 24 around the cylinder head 13 are assembled in this order, and the cylinder head 13 and the bearing cap 13c are fixed with bolts or the like.

  By adopting the above assembling procedure, the needle roller bearing 21 in which the camshaft 19, the outer ring member 22, the cage 24, and the housing are arranged concentrically and the needle roller 23 can rotate stably is provided. Obtainable.

  The raceway surface located on the radially outer side of the needle roller 23 is composed of an inner diameter surface of the outer ring member 22 and an inner peripheral surface of the cylinder head 13 as a housing. Therefore, the inner diameter dimension of the cylinder head 13 is set smaller than the inner diameter dimension of the bearing cap 13c by the plate thickness of the outer ring member 22 so that the connecting portion between the outer ring member 22 and the inner diameter surface of the cylinder head 13 is smooth. Yes. In consideration of thermal expansion and manufacturing errors, a slight gap is provided between the outer ring member 22 and the cylinder head 13.

  As described above, the raceway surface of the needle roller 23 is constituted by the inner diameter surface of the outer ring member 22 and the inner peripheral surface of the cylinder head 13 connected to the circumferential end portion of the outer ring member 22. The manufacturing cost can be reduced. The outer ring member 22 is desirably arranged at a position including the load region when the camshaft 19 is divided into a load region and a non-load region in the circumferential direction. The outer ring member 22 is manufactured through many processing steps as will be described later in order to obtain mechanical properties and surface roughness required for the raceway surface of the needle roller 23. Therefore, even when it is disposed at a position including a load region where a large load is applied, the needle roller 23 can be smoothly rotated.

Note that the "load region", the direction of maximum load area of the right and left 90 ° about the (direction indicated by a phantom line l ₁ in FIG. 5) (Fig. 5 loaded on the needle roller bearing 21 from the camshaft 19 180 ° region indicated by an arc α in the middle). On the other hand, the “non-load region” is a 180 ° region (region indicated by an arc β in FIG. 5) opposite to the direction of the maximum load, and only a relatively small load acts as compared with the load region. This is a region that does not (including the case where the load is zero).

  Further, in the internal combustion engine 11 shown in FIG. 9, the maximum load applied to the needle roller bearing 21 from the camshaft 19 is a reaction of a 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. 9).

  Further, the oil passage (not shown) of the housing constituted by the cylinder head 13 and the bearing cap 13 c is assembled so that the oil hole 22 b provided in the outer ring member 22 coincides. As a result, the amount of lubricating oil supplied to the inside of the bearing is increased, and the lubricity of the needle roller bearing 21 is improved.

  The camshaft support structure in the above embodiment shows an example in which a part of the raceway surface of the needle roller 23 is configured by the inner peripheral surface of the cylinder head 13, but other members are provided on the inner peripheral surface of the cylinder head 13. The raceway surface may be configured by fitting. For example, as shown in FIG. 7, the arc-shaped ring member 25 may be arranged continuously with the circumferential end of the outer ring member 22. Since the ring member is disposed in the non-load region, the ring member may be simply formed by pressing a metal to a predetermined curvature, or may be formed by injection molding a resin material. In this embodiment, the ring member 25 should be regarded as an element constituting the housing.

  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 applicable to other roller bearings such as a cylindrical roller bearing and a rod roller bearing. Can also be applied.

  Moreover, although the example in which the outer ring member 22 in the above embodiment has a semicircular shape with a central angle of 180 ° has been shown, the present invention is not limited to this, and any size can be used as long as the entire load region can be included. An outer ring member 22 having a central angle of 5 mm can be employed. For example, an outer ring member with a small central angle may be used when used in an environment with a small load region, and an outer ring member with a large central angle may be used when used in an environment with a large load region. Similarly, the cage 24 can be of any form.

  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.

  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.

  The present invention is also applicable to a single-cylinder internal combustion engine. However, the shaft portion 15a of the crankshaft 15 employed in a multi-cylinder engine as shown in FIG. 10 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.

  Further, referring to FIG. 8, a camshaft support structure according to another embodiment of the present invention will be described. Since the basic configuration of this camshaft support structure is the same as that of the camshaft support structure shown in FIG. 5, the description of the common points will be omitted and the differences will be mainly described.

  Referring to FIG. 8, a camshaft support structure according to another embodiment of the present invention includes housings 13 and 13c, camshaft 19, and a needle that rotatably supports camshaft 19 with respect to housings 13 and 13c. And a roller bearing 31. The outer ring member 32 employed in the needle roller bearing 31 has a semicircular shape with a central angle of 180 °, and projects radially inward from both axial end portions to move the cage 34 in the axial direction. It has the collar part 32a to regulate. The flange portion 32 a further includes a protruding portion 32 c that protrudes in the circumferential direction from both circumferential ends of the outer ring member 32.

  By setting it as the said structure, the positioning of the axial direction of the holder | retainer 34 can be performed still more reliably. In particular, the effect is great when a segment retainer configured by connecting a plurality of segments in the circumferential direction is employed. In addition, this protrusion part 32c may be integrally formed in the press work process mentioned later, and after forming the outer ring member 32, you may attach it by welding etc.

  Next, a method for manufacturing the outer ring member 22 according to an embodiment of the present invention will be described. 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 hard to form a carburized hardened layer by quenching, and needs to be carbonitrided to obtain the required hardness for the outer ring member 22. 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.

  As a specific manufacturing process of the outer ring member 22, first, an outer shape of the outer ring member 22 is formed by punching a steel plate. In addition, when using a progressive press, while forming the pilot hole for determining the processing position of each processing process, it is good to provide a connection part between adjacent outer ring members.

  Next, the flat outer ring member 22 is bent so as to have a predetermined curvature by bending, and both end portions in the axial direction are bent radially inward to form the flange portion 22a. In this step, bending is performed in a plurality of times in order to prevent damage to the material.

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

  In order for the outer ring member 22 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.

  Finally, in order to make the inner diameter surface, which is the raceway surface of the needle roller 23, a smooth surface, grinding is performed. As a grinding method, barrel polishing or the like is employed.

  In addition, said process process is an example of the manufacturing method of the outer ring member which concerns on this invention, Comprising: Each process may be further subdivided and a required process can also be added further. The order of the processing steps can be arbitrarily changed.

  Furthermore, each of the above steps may be performed by a single press as a separate step, but may be performed by a progressive press or a transfer press. Thereby, each process can be performed continuously. Moreover, by using the manufacturing apparatus of the outer ring member 22 having a processing portion corresponding to all or a part of each of the above steps, the productivity can be increased, and as a result, the product price of the needle roller bearing 21 is suppressed. be able to.

  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

  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 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 a figure which shows the camshaft support structure which concerns on other embodiment of this invention. It is a figure which shows the camshaft support structure which concerns on other embodiment of this invention. It is sectional drawing which shows one cylinder of the internal combustion engine which concerns on one Embodiment of this invention. FIG. 10 is a diagram showing a crankshaft employed in the internal combustion engine of FIG. 9. It is a figure which shows the camshaft employ | adopted as the internal combustion engine 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, 108 Cylinder head, 13a Intake passage, 13b Exhaust passage, 13c Bearing cap, 13d Engaging groove, 14 Piston, 15 Crankshaft, 15a Shaft, 15b Crank arm, 15c Crank pin, 16 connecting rod, 17, 18 valve, 17a, 18a valve stem, 17b, 18b valve head, 17c, 18c valve spring, 19, 101 camshaft, 19a shaft part, 19b cam, 19c long diameter part, 19d short diameter part , 101a Cam lobe, 101b Journal part, 101c End large diameter part, 20 Spark plug, 21, 31 Needle roller bearing, 22, 32 Outer ring member, 22a, 32b collar part, 22b Oil hole, 32c Projection part, 23 Needle shape Roller 24 retainer, 24a, 24b cut end face, 24c pocket 25 ring members, 102 roller bearing, 103 days, 104 and 105 holding body, 106 and 107 race plate, 109 cap.

Claims (3)

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 arc-shaped outer ring member and a plurality of rollers.
The raceway surface located on the radially outer side of the plurality of rollers includes an inner diameter surface of the outer ring member that fits in a region of the housing that accommodates the camshaft, and a circumferential end of the outer ring member. Formed on the inner peripheral surface of
The outer ring member, thin plate is manufactured by performing hardening after pressing, I saw including a flange portion projecting from both axial ends radially inwardly,
The cam shaft support structure , wherein the flange has a protruding portion protruding in a circumferential direction from a circumferential end of the outer ring member .   The camshaft support structure according to claim 1, wherein the outer ring member is disposed at a position including a load region of the camshaft. 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 arc-shaped outer ring member and a plurality of rollers.
The raceway surface located on the radially outer side of the plurality of rollers includes an inner diameter surface of the outer ring member that fits in a region of the housing that accommodates the camshaft, and a circumferential end of the outer ring member. Formed on the inner peripheral surface of
The outer ring member, thin plate is manufactured by performing hardening after pressing, I saw including a flange portion projecting from both axial ends radially inwardly,
The collar portion is an internal combustion engine having a protruding portion protruding in a circumferential direction from a circumferential end portion of the outer ring member .

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