CN101512108B - Roller bearing, camshaft supporting structure, and internal combustion engine - Google Patents

Abstract

A 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 arranged along an inner diameter surface of the outer ring. A slope surface (22i) is provided at one or each circumferential end on an inner diameter surface of the outer ring member (22a), and a contour line of the slope surface (22i) is along a direction perpendicular to a revolution direction of the roller.

Description

Roller bearing, camshaft support structure and internal combustion engine

technical field

The present invention relates to a roller bearing for supporting a camshaft, a crankshaft, a rocker shaft, etc. for an automobile engine, a camshaft support structure using the roller bearing, and an internal combustion engine.

Background technique

For example, JP 2005-180459 A describes a conventional bearing for supporting a camshaft of an automobile engine. Referring to FIG. 21 , the camshaft 101 described in this publication has a cam lobe 101 a , a cylindrical journal portion 101 b supported by a roller bearing 102 , and an end large-diameter portion 101 c.

Here, the outer diameter of the journal portion 101b is smaller than the maximum outer diameter of the cam lobe 101a and the outer diameter of the large-diameter end portion 101c. Therefore, the roller bearing 102 disposed on the journal portion 101b and supporting the camshaft 101 so as to be rotatable cannot be inserted from the axial direction of the camshaft 101 .

The roller bearing 102 has: a plurality of rollers 103; substantially semi-cylindrical holders 104, 105 divided into two in the circumferential direction; Part of the substantially semi-cylindrical raceway plates 106, 107.

The raceway plates 106, 107 have protrusions 106a, 107a protruding radially outward from both axial end faces of the central portion in the circumferential direction, respectively. On the other hand, the cylinder head 108 and the bearing cap 109 are provided with recesses 108 a , 109 a for receiving the protrusions 106 a , 107 a of the raceway plates 106 , 107 . Furthermore, by engaging the protrusions 106a, 107a with the recesses 108a, 109a, respectively, the movement of the track plates 106, 107 in the circumferential direction and the axial direction can be prevented.

22, one end in the circumferential direction of the raceway plate 106 is a wedge-shaped convex portion 106b protruding from the center, and the other end in the circumferential direction is a valley-shaped recess 106c in which the center is recessed. . Then, surface pressing (face pressing) processing is performed on the both ends in the circumferential direction, respectively. As a result, burrs and burrs generated at the ends in the circumferential direction by the press work are trimmed, and the shape of the ends is also trimmed, thereby improving assembly accuracy.

In addition, the raceway plates 106 and 107 of the above-mentioned structure are generally manufactured by press-working a steel plate, such as a cold-rolled steel plate (SPC). In addition, heat treatment is performed to obtain predetermined mechanical properties such as hardness, and the inner diameter surface constituting the raceway surface of the roller 103 is polished so that the roller 103 can rotate smoothly.

Although the above-mentioned publication does not expressly indicate the direction in which the surface pressing process is performed on the two ends of the circumferential direction of the raceway plate 106 of the above-mentioned structure, it is considered to be in accordance with the purpose of trimming burrs and burrs and the purpose of trimming the shape of the end portions. The surface pressing process is performed in a direction (arrow direction in FIG. 22 ) perpendicular to the contour line of the processed portion.

However, the surface pressing processing portion formed in the above direction is inclined to either side of the left and right with respect to the rolling direction of the roller 103. Therefore, the movement of the roller 103 passing through the butt portion of the raceway plates 106, 107 is affected by the surface pushing. The possibility of being disturbed by pressing the processed part.

In addition, in the camshaft supporting structure of the above structure, since the camshaft 101 is rotated, a load deviated in a predetermined direction acts on it, and therefore, in its circumferential direction, it is divided into regions (hereinafter referred to as "regions" where the load is relatively large). load area") and the area where only relatively small loads are loaded (hereinafter referred to as "non-load area").

Therefore, since a large load is applied to the raceway plate disposed at a position including the load area, high machining accuracy is required to maintain smooth rotation of the rollers 103 . On the other hand, since many processes as described above are required in the manufacture of the raceway plate, the manufacturing cost of the raceway plate occupies a large proportion in the overall manufacturing cost of the roller bearing 102 . This tendency is particularly remarkable when high-precision processing is required.

Contents of the invention

An object of the present invention is to provide a bearing for supporting a camshaft or the like of an automobile engine, which is a roller bearing capable of smooth rotation of rollers. Another object of the present invention is to provide a camshaft support structure and an internal combustion engine using such a roller bearing as a bearing for supporting a camshaft.

Another 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 using a roller bearing capable of smoothly rotating the rollers while suppressing manufacturing costs.

A roller bearing according to the present invention includes: an outer ring formed by connecting a plurality of arc-shaped outer ring members in a circumferential direction; and a plurality of rollers arranged along an inner diameter surface of the outer ring. In addition, an inclined surface is provided on at least one end in the circumferential direction of the outer ring member, and a contour line of the inclined surface faces a direction perpendicular to the revolution direction of the roller.

As in the above structure, by providing the inclined surface along the rolling direction of the rollers at the end portions of the outer ring members in the circumferential direction, the rollers passing through the abutting portions of the adjacent outer ring members can roll smoothly. In addition, the effect of the present invention can be obtained as long as the inclined surface is provided at the circumferential end on the side where the rollers first contact among the two circumferential ends of each outer ring member.

Preferably, 0.05≦t/t ₀ ≦0.5 is satisfied when t ₀ is the thickness of the thickest part of the outer ring member and t is the thickness of the inclined surface at the outermost end in the circumferential direction. More preferably, when the inclination angle of the inclined surface is set to θ, 10°≦θ≦45° is satisfied. In order to obtain sufficient effects of the present invention, it is preferable to set the plate thickness and inclination angle of the inclined surface within the above-mentioned ranges.

A camshaft support structure according to the present invention includes: a camshaft; a case for accommodating the camshaft; and a roller bearing for supporting the camshaft so as to be rotatable relative to the case. A roller bearing attracting attention 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. In addition, an inclined surface is provided on at least one end in the circumferential direction of the outer ring member, and a contour line of the inclined surface faces a direction perpendicular to the revolution direction of the roller.

Preferably, the track surface located radially outside of the plurality of rollers is composed of the inner diameter surface of the outer ring member fitted into the region of the housing housing the camshaft and the inner diameter surface of the housing connected to the circumferential end of the outer ring member. The surrounding surface is formed.

As in the above configuration, by setting a part of the raceway surface of the rollers as the inner peripheral surface of the case, the number of components of the roller bearing can be reduced, and thus the overall manufacturing cost can be suppressed. As a result, a highly reliable camshaft support structure can be obtained at low cost.

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

The internal combustion engine of the present invention comprises: a casing; a cylinder arranged in the casing; a valve for opening and closing an air intake passage and an exhaust passage connected to the cylinder; a camshaft for controlling the opening and closing timing of the valve; supporting the camshaft so that it can rotate freely roller bearings. A roller bearing attracting attention 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. In addition, an inclined surface is provided on at least one end in the circumferential direction of the outer ring member, and a contour line of the inclined surface faces a direction perpendicular to the revolution direction of the roller.

By adopting the roller bearing having the above structure, it is possible to obtain a camshaft support structure and an internal combustion engine with a long life and high reliability.

According to the present invention, by providing an inclined surface inclined in the rolling direction of the rollers at the end portion of the inner diameter surface of the outer ring member in the circumferential direction, the movement of the roller passing through the abutting portion of the adjacent outer ring members is stabilized. As a result, a roller bearing in which the rollers can rotate smoothly can be obtained. In addition, by adopting such a roller bearing, a camshaft support structure and an internal combustion engine having a long life and high reliability can be obtained.

A camshaft support structure according to the present invention includes: a camshaft; a case for accommodating the camshaft; and a roller bearing for supporting the camshaft so as to be rotatable relative to the case. The roller bearing that has received attention has an arc-shaped outer ring member and a plurality of rollers, and the raceway surface located radially outside the plurality of rollers is formed by the inner diameter surface of the outer ring member that is fitted into the area where the camshaft is accommodated in the case. It is formed with the inner peripheral surface of the case connected to the circumferential end of the outer ring member.

As in the above configuration, by setting a part of the roller raceway surface as the inner peripheral surface of the case, the number of components of the roller bearing can be reduced, and thus the overall manufacturing cost can be suppressed. As a result, a highly reliable camshaft support structure can be obtained at low cost.

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

The internal combustion engine of the present invention comprises: a casing; a cylinder arranged in the casing; a valve for opening and closing an air intake passage and an exhaust passage connected to the cylinder; a camshaft for controlling the opening and closing timing of the valve; supporting the camshaft so that it can rotate freely roller bearings. The roller bearing that has received attention has an arc-shaped outer ring member and a plurality of rollers, and the raceway surface located radially outside the plurality of rollers is formed by the inner diameter surface of the outer ring member that is fitted into the area where the camshaft is accommodated in the case. It is formed with the inner peripheral surface of the case connected to the circumferential end of the outer ring member.

A highly reliable internal combustion engine can be obtained by employing the camshaft support structure configured as described above.

According to the present invention, the outer ring member is arranged only in the part (load area) that requires high precision in the raceway surface of the roller, and the other part is formed by the inner peripheral surface of the case, thereby maintaining the rigidity of the roller while suppressing the manufacturing cost. Spins smoothly. As a result, a highly reliable camshaft support structure and an internal combustion engine can be obtained at low cost.

Description of drawings

FIG. 1 is a diagram showing a state before assembly of a camshaft support structure according to an embodiment of the present invention.

Fig. 2 is a diagram showing an outer ring member of a roller bearing according to an embodiment of the present invention.

Fig. 3 is a view viewed from the direction III of Fig. 2 .

FIG. 4 is a view seen from the IV direction of FIG. 2 .

Fig. 5 is a view showing an inner diameter surface of the outer ring member of Fig. 2 .

Fig. 6 is an enlarged view of a mated portion when the outer ring member of Fig. 2 is mated.

Fig. 7 is a side view showing a roller bearing cage according to an embodiment of the present invention.

FIG. 8 is a partial cross-sectional view including a divided portion of the holder of FIG. 7 .

9 is a cross-sectional view of the assembled state of the camshaft support structure of FIG. 1 viewed from the axial direction.

10 is a cross-sectional view of the assembled state of the camshaft support structure of FIG. 1 viewed from the radial direction.

11 is a view showing a part of the manufacturing process of the outer ring member according to the embodiment of the present invention, the upper layer is a plan view, and the lower layer is a cross-sectional view.

12 is a view showing a state before assembly of a camshaft support structure according to another embodiment of the present invention.

Fig. 13 is a diagram showing an outer ring member of the roller bearing of Fig. 12 .

14 is a cross-sectional view of the assembled state of the camshaft support structure of FIG. 12 viewed from the axial direction.

15 is a cross-sectional view of the assembled state of the camshaft support structure of FIG. 12 viewed from the radial direction.

FIG. 16 is a diagram showing a camshaft support structure of another embodiment shown in FIG. 12 .

FIG. 17 is a diagram showing a camshaft support structure of still another embodiment shown in FIG. 12 .

18 is a cross-sectional view showing one cylinder of the internal combustion engine according to the embodiment of the present invention.

Fig. 19 is a diagram showing a crankshaft used in the internal combustion engine of Fig. 18 .

Fig. 20 is a diagram showing a camshaft used in the internal combustion engine of Fig. 18 .

Fig. 21 is a diagram showing a conventional camshaft support structure.

Fig. 22 is an enlarged view of a raceway plate of the roller bearing of Fig. 21 .

Detailed ways

An internal combustion engine 11 according to an embodiment of the present invention will be described with reference to FIGS. 18 to 20 . 18 is a sectional view showing one cylinder of an internal combustion engine 11 according to an embodiment of the present invention, FIG. 19 is a diagram showing a crankshaft 15 used in the internal combustion engine 11, and FIG. 20 is a diagram showing a camshaft 19 used in the internal combustion engine 11.

First, with reference to Fig. 18, the internal combustion engine 11 is a reciprocating engine, which includes: a cylinder block 12 and a cylinder head 13 as a box; a motion conversion mechanism that converts reciprocating motion into rotational motion; Exhaust supply and exhaust mechanism of exhaust gas; spark plug 20 as ignition device.

The motion conversion mechanism includes: a piston 14 housed in a cylinder block 12 that reciprocates inside a cylinder 12a provided in the cylinder block 12; a crankshaft 15 passing through a flywheel (not shown) and a coupling (not shown) It is connected with the transmission device (not shown); the connecting rod 16 is connected with the piston 14 at one end and the crankshaft 15 at the other end, and converts the reciprocating motion of the piston 14 into the rotary motion of the crankshaft 15 .

The air supply and exhaust mechanism includes: an air intake passage 13a and an exhaust passage 13b formed on the cylinder head 13 and communicated with the cylinder 12a; an air intake valve 17 as a valve disposed between the cylinder 12a and the air intake passage 13a; The air valve 18 is a valve disposed between the cylinder 12 a and the exhaust passage 13 b ; and the camshaft 19 controls the opening and closing timing of the intake valve 17 and the exhaust valve 18 .

Inhalation valve 17 comprises: valve stem 17a; The valve head 17b that is arranged on one side end of valve stem 17a; The other end is connected with a camshaft 19 . The exhaust valve 18 has the same structure as the intake valve 17, and therefore description thereof will be omitted.

Referring to Fig. 19 , the crankshaft 15 used in the internal combustion engine 11 has: a shaft portion 15a; crank arms 15b; and a crank pin 15c for disposing the connecting rod 16 between adjacent crank arms 15b. A shaft portion 15 a of the crankshaft 15 is rotatably supported by a needle bearing 21 according to an embodiment of the present invention which will be described later. In addition, the number of crank pins 15c is set to be the same as the number of cylinders of the internal combustion engine 11 .

Referring to Fig. 20 , the camshaft 19 used in the 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 bearing 21 according to an embodiment of the present invention which will be described later. The camshaft 19 is connected to a timing belt (not shown) via the crankshaft 15 and rotates as the crankshaft 15 rotates.

The cams 19b are connected to the intake valve 17 or the exhaust valve 18, respectively, and thus are set to the same number as the valves 17 and 18. In addition, as shown in FIG. 18, the cam 19b includes a long-diameter portion 19c with a relatively large diameter and a short-diameter portion 19d with a relatively small diameter. As shown in FIG. Configure in a staggered manner. Thereby, the valves 17 and 18 respectively connected to the plurality of cams 19b can be opened and closed with timing shifted.

In addition, the internal combustion engine 11 is a DOHC (Double Over Head Camshaft) type engine in which the camshaft 19 is arranged above the cylinder head 13 and provided on the intake valve 17 side and the exhaust valve 18 side respectively.

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

First, when the process of moving the piston 14 between the uppermost limit position (top dead center) and the lowermost limit position (bottom dead center) in the cylinder 12a is called a process, the internal combustion engine 11 is composed of an intake process, a compression process, A four-stroke engine composed of four processes, combustion process and exhaust process.

In the intake process, the piston 14 moves from the upper dead center to the lower 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, the same applies hereinafter) increases and the internal pressure decreases, so that air-fuel mixture flows into the cylinder 12a from the intake passage 13a. Mixed gas refers to the mixture of air (oxygen) and mist gasoline.

In the compression process, the piston 14 moves from the bottom dead center to the top dead center with the suction valve 17 and the discharge valve 18 closed. As a result, the volume inside 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 is rapidly expanded by combustion, and the piston 14 is pushed from the top dead center to the bottom dead center. The connecting rod 16 transmits this force to the crankshaft 15 as a rotational motion, thereby generating a driving force.

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 decreases, and the combustion exhaust gas flows out from the exhaust passage 13b. In addition, in this process, after the piston 14 reaches the top dead center, it returns to the intake process.

In each of the above steps, "the state where the suction valve 17 is opened" refers to a state where the long-diameter portion 19c of the cam 19b is in contact with the suction valve 17, and the suction valve 17 is pressed downward against the valve spring 17c. The state in which the valve 17 is closed” refers to 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. In addition, the same applies to the exhaust valve 18, and description thereof will be omitted.

In each of the above steps, the driving force is generated only in the combustion step, and the piston 14 is reciprocated by the driving force generated in other cylinders in the other steps. Therefore, from the viewpoint of maintaining smooth rotation of the crankshaft 15, it is preferable to shift the timing of the combustion process among the plurality of cylinders.

1 to 10 , a needle bearing 21 as a roller bearing according to an embodiment of the present invention and a camshaft support structure using the needle bearing 21 will be described. 1, 9 and 10 are diagrams showing states before and after assembly of a camshaft support structure according to an embodiment of the present invention, and Figs. 2 to 8 are diagrams showing components of a needle roller bearing 21 according to an embodiment of the present invention. picture.

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 cover 13c as a box housing the camshaft 19; Body rotatable needle bearing 21.

The needle roller bearing 21 includes: an outer ring 22 formed by connecting a plurality of arc-shaped outer ring members 22a, 22b in the circumferential direction; needle rollers 23 as a plurality of rollers arranged along the inner diameter surface of the outer ring 22; At one place on the circumference, there is a retainer 24 that keeps a plurality of needle rollers 23 at intervals along a dividing line extending in the axial direction of the bearing.

As a bearing for supporting the camshaft 19, a needle bearing 21 is generally used. Since the needle roller bearing 21 makes the needle roller 23 in line contact with the raceway surface, a high load capacity and high rigidity can be obtained although the projected area of the bearing is relatively small. Therefore, it is preferable to reduce the radial thickness dimension of the support portion while maintaining the load capacity.

The outer ring member 22a will be described with reference to FIGS. 2 to 6 . 2 is a side view of the outer ring member 22a, FIG. 3 is a view of FIG. 2 viewed from the III direction, FIG. 4 is a view of FIG. 2 viewed from the IV direction, and FIG. 5 is a view of the outer ring member 22a viewed from the inner diameter side, FIG. 6 is a diagram showing a mating portion of the outer ring members 22a, 22b. In addition, since the outer ring member 22b has the same shape as the outer ring member 22a, description thereof will be omitted.

First, referring to FIG. 2, the outer ring member 22a has a semicircular shape with a center angle of 180°, and has engaging pawls 22c bent outward in the radial direction at one end in the circumferential direction and extending from both ends in the axial direction. A flange portion 22d protruding radially inward. The engaging claw 22c is engaged with the cylinder head 13 to prevent the outer ring member 22a from rotating relative to the case. The flange portion 22d improves the lubricating oil retention property of the bearing while restricting the cage 24 from moving in the axial direction. Then, the two outer ring members 22a and 22b are connected in the circumferential direction to form an annular outer ring 22 . In addition, the axial center portion of the inner diameter surface of the outer ring 22 functions as a raceway surface of the needle roller 23 .

In addition, as described with reference to FIG. 3 , two engagement claws 22 c are provided at both ends in the axial direction at one end portion of the outer ring member 22 a in the circumferential direction, and a groove concave in the circumferential direction is formed between the two engagement claws 22 c. The substantially V-shaped concave portion 22e. In addition, the two engaging claws 22c are arranged at both end portions avoiding the axial center portion of the raceway surface constituting the outer ring member 22a, and are arranged on a straight line parallel to the rotation axis of the needle bearing 21 . That is, the length L between the two engaging claws 22 c is set to be longer than the effective length l of the needle roller 23 . In addition, in this specification, "the effective length of a roller" means the length which subtracted the length of the chamfered part of both ends from the length of a roller.

In addition, as described with reference to FIG. 4 , two flat portions 22 having the same width as the axial width of the engaging claw 22c are provided at both ends in the axial direction on the other end portion in the circumferential direction of the outer ring member 22a. A substantially V-shaped convex portion 22g whose tip protrudes in the circumferential direction in an arc shape is provided between the flat portions 22f. Furthermore, when the outer ring members 22a, 22b are connected in the circumferential direction, the concave portion 22e receives the convex portion 22g of the adjacent outer ring member. As described above, the needle roller 23 can be smoothly rotated by setting the shape of the mating portion to be substantially V-shaped. In addition, the shape of the abutting portion of the outer ring members 22a and 22b is not limited to a substantially V-shape, but may be any shape in which the needle roller 23 can rotate smoothly, such as 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 case, and supplies lubricating oil to the inside of the needle roller bearing 21. In addition, the size, position, and number of oil holes 22h depend on the size, position, and number of oil passages provided in the case.

In addition, referring to FIG. 5, an inclined surface 22i (shaded portion in FIG. 5) is provided at both ends of the inner diameter surface of the outer ring member 22a in the circumferential direction. A direction perpendicular to the revolution direction of the needle 23 . As described above, the inclined surfaces 22i inclined to the rolling direction of the needle rollers 23 are provided at both ends of the outer ring members 22a, 22b in the circumferential direction, whereby the needle rollers passing through the abutting portions of the adjacent outer ring members 22a, 22b 23 was able to roll smoothly.

In addition, in this embodiment, the inclined surface 22i on the side (upper side in FIG. 5 ) on which the convex portion 22g is formed is provided at the center portion in the axial direction, that is, around the front end portion of the convex portion 22g. On the other hand, the inclined surface 22i on the side where the recess 22e is formed (the lower side in FIG. 5 ) is provided at both ends in the axial direction, that is, on both sides of the opening of the recess 22e.

Furthermore, referring to FIG. 6, the inclined surface 22i is a tapered surface inclined at a predetermined inclination angle θ from the outermost portion in the circumferential direction to the central portion in the circumferential direction. The plate thickness is the smallest (t) at the outermost portion in the circumferential direction, and is constant (t ₀ ) in the central portion in the circumferential direction, that is, the region between the two inclined surfaces 22i. Here, in order to obtain sufficient effects of the present invention, it is preferable to set 0.05≦t/t ₀ ≦0.5, and 10°≦θ≦45°. In addition, the "inclination angle θ" refers to an angle formed by a straight line perpendicular to the end surface of the outer ring member 22 a in the circumferential direction and an inclined surface.

Regarding the plate thickness, when t ₀ /t<0.05 is set, the needle rollers 23 passing through the abutting portion of the adjacent outer ring members 22a, 22b collide with the corners formed at the ends in the circumferential direction, causing the needle rollers 23 to be disturbed. action or scratch the rolling surface. On the other hand, when t ₀ /t>0.5, the needle rollers 23 fit into the dimples formed at the mating portions of the outer ring members 22a, 22b, preventing smooth rotation of the needle roller bearings 21 .

As for the inclination angle, when θ<10°, t ₀ must be reduced to a certain extent in order to obtain sufficient effects of the present invention, and as a result, the circumferential length of the inclined surface 22i becomes longer. This causes the strength of the outer ring members 22a, 22b to decrease. On the other hand, when θ > 45°, the needle rollers 23 passing through the abutting portion of the adjacent outer ring members 22a, 22b collide with the corner formed at the end point (central side in the circumferential direction) of the inclined surface 22i, resulting in disturbed rolling. The action of the needle 23 or scratch the rolling surface. Therefore, in order to avoid the above disadvantages, it is preferable that the plate thickness and inclination angle are within the above ranges.

Next, the retainer 24 will be described with reference to FIGS. 7 and 8 . FIG. 7 is a side view of the holder 24 , and FIG. 8 is a partial cross-sectional view including a divided portion of the holder 24 . The cage 24 has a substantially C-shape having a parting line extending in the axial direction of the bearing at one location on the circumference, and pockets 24c for accommodating the needle rollers 23 are provided at equal intervals in the circumferential direction. In addition, the retainer 24 is formed by injection molding a resin material.

In addition, a recess 24d is provided on one cut end surface 24a in the circumferential direction of the divided portion, and a protrusion 24e corresponding to the recess 24d is provided on the other cut end face 24b, and the recess 24d and the protrusion 24e engage, thereby, A ring-shaped retainer 24 can be obtained. In this embodiment, the width of the front end 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 side. Thereby, the engagement of the recessed part 24d and the convex part 24e is made reliable.

Next, the procedure for assembling the needle bearing 21 to the camshaft 19 will be described with reference to FIGS. 1 , 9 and 10 .

First, the needle rollers 23 are assembled to the pockets 24c of the cage 24, respectively. Next, the split portion is expanded by the elasticity of the retainer 24 and assembled to the camshaft 19 . Furthermore, the recessed part 24d is engaged with the convex part 24e so that the retainer 24 does not come off.

Next, on the cylinder head 13, the outer ring member 22a on one side, the camshaft 19 fixed by winding the retainer 24, the outer ring member 22b on the other side, and the bearing cap 13c are sequentially assembled, and the cylinder head 13 is fixed with bolts or the like. and bearing cap 13c. At this time, the concave portion 22e of the outer ring member 22a is arranged to abut against the convex portion 22g of the outer ring member 22b, and the convex portion 22g of the outer ring member 22a is abutted against the concave portion 22e of the outer ring member 22b.

In addition, the engaging claws 22c of the outer ring member 22a are engaged with the engaging grooves 13d provided on the surface of the cylinder head 13 that is in contact with the bearing cap 13c, and the engaging claws 22c of the outer ring member 22b are engaged with those of the bearing cap 13c. The engaging groove 13d provided on the mating surface of the cylinder head 13 is engaged. Thereby, the outer ring members 22a and 22b can be prevented from rotating inside the case during bearing rotation.

In the above embodiment, an example was shown in which the needle bearing 21 is used as the bearing for supporting the camshaft 19, but the present invention can also be applied to other roller bearings such as cylindrical roller bearings and long cylindrical roller bearings.

In addition, the example including the outer ring 21, the needle rollers 23, and the cage 24 was shown for the needle roller bearing 21 of the above-mentioned embodiment, but it is not limited thereto, and may be a full complement roller type in which the cage 24 is omitted. roller bearing) roller bearings.

In addition, although the example of the tapered surface whose inclination angle is [theta] was shown about the inclined surface 22i of the said embodiment, it is not limited to this, It may have arbitrary shapes. For example, it may be a convex curved surface or the like.

In addition, the inclined surface 22i of the above-mentioned embodiment may be provided over the entire width of the track surface (the area surrounded by a two-dot chain line in FIG. 5 ), but as shown in this embodiment, it may also be provided at the part of the width. In this case, the effect of the present invention can be obtained as long as the needle roller 23 first contacts the portion passing through the butt portion of the adjacent outer ring members 22a, 22b, that is, the hatched portion in FIG. 5 .

In addition, an example in which the outer ring members 22a and 22b are divided into two places in the circumferential direction was shown for the outer ring 22 of the above-mentioned embodiment, but the present invention is not limited thereto, and may be divided into any number. For example, three outer ring members having a central angle of 120° may be connected in the circumferential direction to form the outer ring. In addition, a plurality of outer ring members having different central angles may be combined to form an annular outer ring. Similarly, any type of holder may be used for the holder 24 .

In addition, although the cage 24 of the above-mentioned embodiment shows an example of a resin cage with high production efficiency and high elastic deformability, it is not limited to this, and may be a cutting cage by cutting, or, A stamped retainer that presses a steel plate may also be used.

In addition, the needle bearing 21 of the above-described embodiment can be widely used not only as a bearing for supporting the camshaft 19 but also as a bearing for supporting the shaft portion 15a of the crankshaft 15 shown in FIG. 19 , a rocker shaft, and the like.

Furthermore, the present invention can be applied to a single-cylinder internal combustion engine, but it is also preferable that the shaft portion 15a of the crankshaft 15 used in the multi-cylinder engine shown in FIG. 19 and the shaft portion 19b of the camshaft 19 shown in FIG. A bearing that supports the needle roller bearing 21 from the position where it is inserted in the axial direction.

In addition, in the above-mentioned embodiment, an example is shown in which the present invention is applied to the outer ring members 22a, 22b provided with the engaging claws 22c engaged with the case at the ends in the circumferential direction, and Both ends are provided with flange portions 22d for restricting axial movement of the retainer 24. However, the engaging claws 22c and the flange portions 22b are not essential components of the present invention, and various types of outer ring members may be used.

Next, a method of manufacturing the outer ring member 22a according to one embodiment of the present invention will be described with reference to FIG. 11 . 11 is a diagram showing a part of the manufacturing process of the outer ring member 22a, the upper layer is a plan view, and the lower layer is a side view. In addition, since the manufacturing method of the outer ring member 22b is the same as that of the outer ring member 22a, description thereof will be omitted.

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

In addition, carbon steel with a carbon content of less than 0.15 wt% is less likely to form a carburized hardened layer by quenching treatment, and carbonitriding treatment is required to obtain the hardness required for the outer ring member 22a. The carbonitriding treatment is expensive in terms of facility cost compared with each of the quenching treatments described later, and as a result, the manufacturing cost of the needle bearing 21 increases. In addition, carbon steel with a carbon content of less than 0.15 wt% may not obtain a sufficient carburized hardened layer even if it is carbonitrided, and surface origin type peeling may occur prematurely on the raceway surface. On the other hand, since carbon steel with a carbon content of more than 1.1 wt % significantly lowers the workability, there are problems of lowered working accuracy and increased manufacturing costs due to increased working man-hours.

Referring to FIG. 11 , as a first step, a steel plate is press-worked to form the outer shape of the outer ring member 22 a (step a). A portion constituting the recessed portion 22e and the engaging claw 22c is formed at one end portion in the longitudinal direction, and a flat portion 22f and a convex portion 22g are formed at the other end portion. In addition, the oil hole 22h may be processed simultaneously with the outer shape.

At this time, the length in the longitudinal direction of the outer ring member 22 a is determined based on the diameter of the camshaft 19 , and the length in the width direction is determined based on the roller length of the needle roller 23 used. However, the width direction includes the portion constituting the flange portion 22d, so the length in the width direction in this step is longer than the axial width dimension of the finished product of the outer ring member 22a.

In this step, all the parts may be punched in one press, or a predetermined shape may be obtained by repeating the press a plurality of times. In addition, when continuous press is used, the guide hole 25 for determining the processing position of each processing step is formed, and the connecting portion 26 is provided between the adjacent outer ring member.

As a second step, the inclined surface 22i is formed on the end portion of the outer ring member 22a in the circumferential direction by surface pressing (step b).

As a third step, the circumferential end portion of the outer ring member 22a is bent radially outward by bending to form the engagement claw 22c (step c). The bending angle of the engaging claw 22c is an angle along the engaging groove 13c of the case. In addition, in this embodiment, the engaging claw 22c is bent at an angle of 90° with respect to the outer ring member 22a.

The fourth step includes a step of bending the outer shape of the curved member 22a to a predetermined curvature by bending and a step of forming flange portions 22d protruding radially inward at both ends of the outer ring member 22a in the axial direction (steps d to h). process). Specifically, except for the central portion including the connecting portion 26, it is bent sequentially from both ends in the longitudinal direction (step d, step e). Next, the flange portions 22 d are formed by bending both ends in the width direction on the both end portions in the longitudinal direction that have been bent (step f). Next, the central portion in the longitudinal direction is also bent so that the outer shape of the outer ring member 22a has a predetermined curvature (step g). Finally, the connection part 26 is removed, and the flange part 22d is formed in the longitudinal center part (h process).

After the press working process is completed, heat treatment is performed in order 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 22 a functioning as the raceway needs to be 635 or more.

In order to obtain a hardened layer with a sufficient depth for the outer ring member 22a, it is necessary to select an appropriate heat treatment method according to the carbon content of the starting material. Specifically, carburizing and quenching treatment is performed for materials with a carbon content of 0.15 wt% to 0.5 wt%, and bright quenching is performed for materials with a carbon content of 0.5 wt% to 1.1 wt%. Or high-frequency quenching treatment.

Carburizing and quenching treatment is a heat treatment method that utilizes the phenomenon of solid solution carbon in high-temperature steel, and can obtain a surface layer (carburized hardened layer) with a high carbon content when the internal carbon content of the steel is low. As a result, the surface is hard and the inside is soft and tough. In addition, compared with carbonitriding treatment equipment, the equipment cost is low.

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

High-frequency quenching treatment is a method of rapidly heating and quenching the steel surface by using the principle of induction heating to make a quench hardened layer. Compared with other quenching treatment equipment, the equipment cost is greatly reduced, and there is an advantage of good environment because no gas is used in the heat treatment process. In addition, it is also advantageous in that it can be partially quenched.

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

In addition, in this embodiment, an example was shown in which the step of forming the outer shape curvature of the outer ring member 22a and the step of forming the flange portion 22d are performed in parallel, but the present invention is not limited thereto, and the step of forming the outer shape curvature may be The process and the process of forming the flange portion 22d are performed independently.

The above-mentioned first step to fourth step are examples of the manufacturing method of the outer ring member of the present invention, and each step may be subdivided or further necessary steps may be added. In addition, the order of the processing steps may be changed arbitrarily.

In addition, each of the above-mentioned steps (a-step to h-step) may be performed as separate steps on a dedicated press machine, or may be performed by continuous press or multi-station press. Thereby, each process can be performed continuously. In addition, by using a manufacturing apparatus for the outer ring member 22a having a processed portion suitable for all or part of the above-mentioned steps (steps a to h), productivity can be improved, and as a result, the product price of the needle roller bearing 21 can be suppressed.

In addition, "continuous press" in this specification refers to a method in which a plurality of processing steps are provided in a press machine, and a material is moved through each process through a feeder at the entrance of the press machine to continuously process the material. In addition, "multi-station stamping" in this specification means that when multiple processing steps are required, the number of carrying tables for performing each step is set as many as required, and while the work piece is moved by the conveying device, each step is carried out at each step. The method of processing the carrier table.

A needle bearing 41 as a roller bearing according to another embodiment of the present invention and a camshaft support structure using the needle bearing 41 will be described with reference to FIGS. 12 to 15 . The basic structure of the needle roller bearing 41 is the same as that of the needle roller bearing 21, and the description of the same point will be omitted, and the difference will be mainly described. 12 , 14 , and 15 are diagrams showing states before and after assembly of the camshaft support structure, and FIG. 13 is a diagram showing the outer ring member 42 .

First, referring to FIG. 12 , the camshaft supporting structure includes: a camshaft 19; a cylinder head 33 and a bearing cover 33c as a housing for accommodating the camshaft 19; Bearing 41.

The needle roller bearing 41 includes: an arc-shaped outer ring member 42; needle rollers 43 as rollers; and a retainer that has a parting line extending in the direction of the bearing axis at one position on the circumference and keeps the intervals between the plurality of needle rollers 43. 44.

FIG. 13 is a side view of the outer ring member 42 . 13, the outer ring member 42 is a semicircular shape with a central angle of 180°, and has flanges 42a protruding radially inward from both ends in the axial direction to restrict axial movement of the retainer 44, and a flange portion 42a from the outside. The radial surface penetrates to the oil hole 42b on the inner diameter surface. In addition, the axially central portion of the inner diameter surface of the outer ring member 42 functions as a raceway surface of the needle roller 43 . In addition, the oil hole 42 b is provided at a position facing an oil passage (not shown) provided in the case, and supplies lubricating oil to the inside of the needle bearing 41 . In addition, the size, position, and number of oil holes 42b depend on the size, position, and number of oil passages provided in the case.

In addition, the structure of the retainer 44 is the same as that of the retainer 24 shown in FIG. 7 and FIG. 8 , so description thereof will be omitted.

Next, the procedure for assembling the needle bearing 41 to the camshaft 19 will be described with reference to FIGS. 12 , 14 and 15 .

First, the needle rollers 43 are respectively assembled in the pockets 44c of the holder 44 . Next, the split portion is expanded by the elasticity of the retainer 44 and assembled to the camshaft 19 . Next, the concave portion 44d is engaged with the convex portion 44e so that the retainer 44 does not come off.

Next, the camshaft 19 , the outer ring member 42 , and the bearing cap 33 c fixed by being wound around the retainer 44 are sequentially assembled on the cylinder head 33 , and the cylinder head 33 and the bearing cap 33 c are fixed with bolts or the like.

By the above assembly procedure, the camshaft 19 , the outer ring member 42 , the retainer 44 , and the case can be arranged concentrically, and the needle roller bearing 41 in which the needle roller 43 can rotate stably can be obtained.

The raceway surface located radially outside of the needle roller 43 is constituted by the inner diameter surface of the outer ring member 42 and the inner peripheral surface of the cylinder head 33 as a case. Therefore, in order to smooth the connection between the outer ring member 42 and the inner diameter surface of the cylinder head 33, the inner diameter of the cylinder head 33 is set smaller than the outer diameter of the bearing cap 33c by the plate thickness of the outer ring member 42. In addition, a slight gap is provided between the outer ring member 42 and the cylinder head 33 in consideration of thermal expansion and manufacturing errors.

As described above, by forming the raceway surface of the needle roller 43 from the inner diameter surface of the outer ring member 42 and the inner peripheral surface of the cylinder head 33 connected to the end portion of the outer ring member 42 in the circumferential direction, the manufacturing cost of the needle roller bearing 41 can be suppressed. . In addition, when the camshaft 19 is divided into a load area and a non-load area in the circumferential direction, the outer ring member 42 is preferably arranged at a position including the load area. In order to obtain the mechanical properties, surface roughness, etc. required for the raceway surface of the needle roller 43, the outer ring member 42 is manufactured through a plurality of processing steps as will be described later. Therefore, smooth rotation of the needle roller 43 can be maintained even when it is arranged in a load region including a heavy load.

In addition, the "load region" refers to a region of 90° left and right (in FIG. The 180° area shown by the arc α). On the other hand, the "non-load region" refers to the 180° region (the region indicated by the arc β in Fig. 14) on the opposite side to the maximum load direction, where only a relatively small load acts compared to the load region ( including the case where the load is 0).

In addition, in the internal combustion engine 11 shown in FIG. 18, the maximum load from the camshaft 19 on the needle bearing 41 is the reaction of the force pressing the valves 17, 18 downward against the valve springs 17c, 18c, and its direction is the same as that of the camshaft 19. The camshaft 19 presses the valves 17, 18 in the opposite direction (direction of the arrow in FIG. 18).

Furthermore, an oil passage (not shown) of a case composed of the cylinder head 33 and the bearing cap 33 c and the oil hole 42 b provided in the outer ring member 42 are assembled in conformity with each other. thus. The amount of lubricating oil supplied to the inside of the bearing increases, and the lubricity of the needle bearing 41 improves.

The camshaft supporting structure of the above-mentioned embodiment shows an example in which a part of the raceway surface of the needle roller 43 is formed by the inner peripheral surface of the cylinder head 33 , but other members may be fitted into the inner peripheral surface of the cylinder head 33 to constitute the raceway surface. . For example, as shown in FIG. 16 , an arc-shaped ring member 45 may be connected to an end portion of the outer ring member 42 in the circumferential direction. Since the ring member is disposed in the non-loaded region, it can be formed by pressing metal with a predetermined curvature, or can be formed by injection molding a resin material. In addition, in this embodiment, the ring member 45 should be grasped as a structural element which comprises a case.

In addition, in the above embodiment, an example is shown in which the needle bearing 41 is used as the bearing for supporting the camshaft 19, but the present invention can also be applied to other roller bearings such as cylindrical roller bearings and long cylindrical roller bearings.

In addition, the outer ring member 42 of the above-mentioned embodiment has shown an example of a semicircular shape with a center angle of 180°, but it is not limited to this, and any outer ring with a center angle can be used as long as it has a size that can cover the entire load area. Member 42. For example, when used in an environment with a small load, an outer ring member with a small central angle can be used, and when used in an environment with a large load, an outer ring member with a large central angle can be used. Likewise, any type of device can be used for the retainer 44 .

In addition, the cage 44 of the above-mentioned embodiment shows an example of a resin cage with high production efficiency and high elastic deformability, but it is not limited to this, and may be a cutting cage using cutting processing, or may be It is a stamped retainer for stamping steel plate.

In addition, the needle bearing 41 of the above-described embodiment can be widely used not only as a bearing for supporting the camshaft 19 but also as a bearing for supporting the shaft portion 15 a of the crankshaft 15 shown in FIG. 19 , a rocker shaft, and the like.

In addition, the present invention can also be applied to a single-cylinder internal combustion engine, but it is also preferable as the shaft portion 15a of the crankshaft 15 used in the multi-cylinder engine shown in FIG. 19 and the shaft portion 19b of the camshaft 19 shown in FIG. 20. A bearing that cannot be supported from a position where the needle bearing 41 is inserted in the axial direction.

Furthermore, the camshaft supporting structure of another embodiment shown in FIG. 12 will be described with reference to FIG. 17 . Since the basic structure of this camshaft support structure is the same as that of the camshaft support structure shown in FIG. 14 , the description of the same points will be omitted, and the different points will be described.

Referring to FIG. 17 , the camshaft support structure includes: housings 33 and 33c; a camshaft 19; and a needle bearing 51 that supports the camshaft 19 so as to be rotatable relative to the housings 33 and 33c. The outer ring member 52 used in the needle roller bearing 51 has a semicircular shape with a center angle of 180°, and has flange portions 52 a protruding radially inward from both ends in the axial direction to restrict axial movement of the cage 54 . The flange portion 52 a also has protrusions 52 c protruding in the circumferential direction from both ends of the outer ring member 52 in the circumferential direction.

By having the above structure, the axial positioning of the retainer 54 can be performed more reliably. In particular, the effect is remarkable when a segment holder configured by connecting a plurality of segments in the circumferential direction is used. In addition, the protruding portion 52c may be integrally formed in a press working process described later, or may be attached after forming the outer ring member 52 by welding or the like.

Next, a method of manufacturing the outer ring member 42 shown in FIG. 13 will be described. In addition, the description of the same points as the manufacturing method of the outer ring member 22a will be omitted, and the description will focus on the different points. Specifically, since the composition of the starting material and the heat treatment process are the same, descriptions thereof are omitted.

As a specific manufacturing process of the outer ring member 42 , first, the outer shape of the outer ring member 42 is formed by pressing a steel plate. When continuous punching is used, it is possible to form a connecting portion between adjacent outer ring members while forming guide holes for determining the processing positions of each processing step.

Next, the flat plate-shaped outer ring member 42 is bent to have a predetermined curvature by bending, and the both ends in the axial direction are bent radially inward to form the flange portion 42a. In this step, the bending process is performed several times in order to prevent breakage of the material or the like.

After the press working process is completed, heat treatment is performed in order to obtain predetermined mechanical properties such as hardness required for the outer ring member 42 . In addition, the surface hardness Hv of the inner diameter surface of the outer ring member 42 functioning as the raceway needs to be 635 or more.

After the heat treatment, grinding is performed so that the inner diameter surface serving as the raceway surface of the needle roller 43 becomes a smooth surface. As a polishing method, barrel polishing is employed.

The embodiments of the present invention have been described above with reference to the drawings, but the present invention is not limited to the illustrated embodiments. Various modifications and variations can be added to the illustrated embodiments within the same or equivalent scope as the present invention.

Industrial Applicability

The present invention is beneficial for use in roller bearings that support camshafts for automotive engines, camshaft support structures, and internal combustion engines.

Claims (7)

1. roller bearing, it possesses:

The cycle component of a plurality of circular shapes is linked to each other and the outer ring of formation in a circumferential direction;

A plurality of rollers of the aperture surface configuration of said outer ring, edge,

Said roller bearing is characterised in that,

Said cycle component has the engaging pawl that engages geocentric vertical outside bending with casing at a side end of its circumferencial direction,

Said engaging pawl is configured on the straight line parallel with the spin axis of said roller bearing at the two end part as the axial central part of plane of trajectory orbital of avoiding of said cycle component,

Circumferencial direction end at least one side of the aperture surface of said cycle component is provided with the plane of inclination, the isohypse of said plane of inclination towards with the direction of the revolution direction quadrature of said roller.

2. roller bearing according to claim 1, wherein,

When the thickest thickness of slab with said cycle component is set at t ₀, when the thickness of slab of the said plane of inclination of the end of circumferencial direction is set at t, satisfy

0.05≤t/t ₀≤0.5。

3. roller bearing according to claim 1, wherein,

When the angle of inclination with said plane of inclination is set at θ, satisfy

10°≤θ≤45°。

4. camshaft supporting structure, it possesses:

Camshaft;

Accommodate the casing of said camshaft;

Support said camshaft and make it with respect to the said casing rotation described roller bearing of claim 1 freely.

5. camshaft supporting structure according to claim 4, wherein,

Said cycle component is disposed at the position that comprises load area of said camshaft.

6. camshaft supporting structure, it possesses:

Camshaft;

Accommodate the casing of said camshaft;

Support said camshaft and make it with respect to said casing rotation roller bearing freely,

Wherein, said roller bearing possesses cycle component and a plurality of roller of circular shape,

Said cycle component has the engaging pawl that engages geocentric vertical outside bending with casing at a side end of its circumferencial direction,

Said engaging pawl is configured on the straight line parallel with the spin axis of said roller bearing at the two end part as the axial central part of plane of trajectory orbital of avoiding of said cycle component,

The plane of trajectory orbital that is arranged in the radial outside of said a plurality of rollers is formed by the aperture surface of the said cycle component in the zone of accommodating said camshaft that embeds said casing and the inner peripheral surface of the said casing that links to each other with the circumferencial direction end of said cycle component.

7. internal-combustion engine, it possesses:

Casing;

Be arranged at the cylinder in the said casing;

The air-breathing road that switching is communicated with said cylinder and the valve of exhaust line;

Control the switching camshaft constantly of said valve;

Support said camshaft and make its rotation described roller bearing of claim 1 freely.

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