JP2006063955A - Lubricating device for engine valve system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lubricating device for an engine 1 valve system improving lubrication of mutual contact parts of a stem end and an inner wall of a tappet and suppressing wear without causing difficulty of securing installation space and cost increase. <P>SOLUTION: In the lubricating device for the engine valve system provided with a valve (exhaust valve) 4 supported on a cylinder head 2 and opening and closing a combustion chamber C, the tappet 5 slidably supported in the cylinder head 2, a cam (exhaust cam) 7 applying pressing force Fo in an open direction on the valve 4 via a top wall 501 of the tappet 5, an oil reservoir 22 is formed on an upward surface of a retainer 25. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a lubrication device for an engine valve system that transmits a pressing force in a valve opening direction from a cam to a valve, and more particularly to an engine valve system that transmits a pressing force from a cam to a valve via a tappet. The present invention relates to a lubrication device.

The engine valve system is configured to transmit the rotation of the crankshaft to the camshaft side and transmit the pressing force generated by the cam integral with the camshaft to the intake valve and the exhaust valve as the opening / closing driving force using the valve operating member.
Among such engine valve operating systems, for example, a direct acting valve operating apparatus shown in FIG. 7 is known.

  In this direct acting valve gear, an inverted cup-shaped tappet 120 that slides along a guide hole 110 formed in the cylinder head 100 is used, and this is attached to the stem end 131 of the valve 130. This prevents the stem end 131 from directly receiving a deviation component (a component orthogonal to the stem end axis) of the pressing force of the cam 140 to prevent the shake, and the pressing force from the cam 140 (the axial direction of the stem end). The component end) is directly received by the stem end 131 through the top wall 121 of the tappet 120.

  This direct-acting valve operating device has few sprung members, is easy to cope with high engine rotation, and its use is increasing. By the way, the tappet 120 used in the direct acting valve gear has a reverse cup shape, so that oil does not fall into the internal space of the tappet 120, the tappet inner wall 122 located in the internal space, the stem end Lubricating oil is supplied to the parts such as 131, the retainer 150, and the upper part of the spring 160 that are in contact with each other only by oil scattered from below or from the side. In addition to this, oil may be supplied separately using an oil jet device.

  An example of a technique that can improve the lubricity of the outer peripheral surface of a tappet used in a direct acting valve gear is disclosed in Japanese Patent Laid-Open No. 8-14021 (Patent Document 1).

JP-A-8-14021

  By the way, as described above, since a reverse cup-shaped tappet is used in the direct acting type valve gear, a retainer attached to a contact portion between the inner wall surface of the top wall 121 and the stem end 131 or in the vicinity of the stem end 131 is used. 150, the cotter 170, the upper part of the spring 160, etc. are located in the internal space of the tappet. For this reason, these members cannot receive the oil supply from above, and lubricate the sliding contact surfaces by receiving the scattered oil from the side or below, leading to an insufficient amount of lubricating oil. There is a problem that it is easy. In particular, the gap between the contact portions where the inner wall surface of the tappet top wall 121 and the stem end 131 come into contact has a small amount of scattered oil, the lubricity of the contact portions decreases, and wear tends to proceed excessively. Improvement is desired.

In addition, when an oil jet device is used separately, problems such as difficulty in securing a mounting space and an increase in cost tend to occur. Furthermore, although the technique of Patent Document 1 can improve the lubricity of the outer peripheral wall of the tappet, it cannot improve the lubricity of the contact portion between the inner wall surface of the tappet and the stem end and the surrounding area.
The present invention solves the above-mentioned problems, and can improve the lubrication of the contact portion between the stem end and the inner wall of the tappet without incurring the problem of securing the mounting space and increasing the cost, thereby suppressing wear. It is an object of the present invention to provide a lubrication device for an engine valve system.

  The invention according to claim 1 is a valve supported by a cylinder head for opening and closing a combustion chamber, a retainer attached in the vicinity of a stem end of the valve, a tappet supported slidably in the cylinder head, In a lubricating system for an engine valve system including a cam for applying a pressing force in the opening direction to the valve via a top wall, an oil sump is formed on an upward surface of the retainer.

  According to a second aspect of the present invention, in the engine valve system lubricating apparatus according to the first aspect, a through hole 23 is formed in the top wall of the tappet so as to face the oil reservoir.

  According to a third aspect of the present invention, in the engine valve system lubricating device according to the first or second aspect, the oil reservoir is formed by a flange portion extending upward from an outer peripheral edge of the retainer. .

  Even if the stem end of the valve is covered with a tappet, the oil reservoir of the retainer in the vicinity of the stem end that moves up and down the oil scattered from the lower side or the side of the tappet accepts the oil. Can be supplied by being scattered in the gaps between the contact portions with the inner wall, improving the lubrication of the contact portions with each other and suppressing wear. In particular, even if the stem end is a direct-acting valve operating apparatus that is arranged to face the cam via the top wall of the tappet, the same effect can be obtained.

Moreover, according to the present invention, the oil reservoir easily receives the oil flowing down from the through hole 23 in the top wall of the tappet, and supplies the oil sufficiently to the gap between the stem end and the inner wall of the tappet by scattering. It is possible to improve the lubrication of the contact portions with each other, and more reliably suppress wear.
Further, according to the present invention, the flange portion on the outer peripheral edge of the retainer can form an oil reservoir having a relatively large capacity, and the amount of oil supplied to the clearance between the stem end and the inner wall of the tappet can be easily secured.

1 and 2 show a cylinder head 2 of an engine 1 equipped with an engine valve system lubrication device as one embodiment of the present invention, a suction / exhaust valve system disposed therein, and the same suction system. The suction and exhaust valves 3 and 4 driven by the exhaust system are shown.
The valve system of the engine shown in FIGS. 1 and 2 is a direct-acting valve operating system in which the stem ends 301 and 401 of the intake and exhaust valves 3 and 4 are sucked through the top wall of the tappet 5 and face the exhaust cams 6 and 7. is there. The cylinder head 2 that accommodates the direct acting valve device has its lower wall 201 superimposed on the upward surface of the cylinder block 8 and is integrally fastened to form the main part of the engine body. . The engine body constitutes a multi-cylinder engine in which a plurality of cylinders are sequentially arranged in the longitudinal direction of the cylinder head 2 (the vertical direction in FIGS. 1 and 2), and each combustion chamber formed in the lower wall 201 of the cylinder head 2 Suction and exhaust ports 9 and 10 are formed on a wall fa facing C (shown in FIG. 1 and FIG. 2 shows one combustion chamber). The intake port 9 of each combustion chamber C introduces intake air into the combustion chamber C in a timely manner when the intake valve 3 is driven to open and close, and the exhaust port 10 discharges exhaust gas from the combustion chamber C when the exhaust valve 3 is driven to open and close. It has a function to make it.

  The cylinder head 2 includes an upper deck 11 having a function as a plurality of port forming walls and a water jacket forming wall on the upper side of the lower wall 201, and a valve system accommodating space 12 is formed on the upper deck 11. . The engine 1 is a DOHC engine, and a pair of suction and exhaust camshafts 13 and 14 extending in the longitudinal direction of the cylinder head 2 (in the direction perpendicular to the paper in FIGS. 1 and 2) are parallel to the accommodation space 12 at a predetermined interval. Deployed. The suction and exhaust camshafts 13 and 14 are pivotally supported on the inner wall side of the cylinder head 2 via bearing members 15 and connected to a crankshaft (not shown) via a rotation transmission system (not shown). It is driven to rotate at half the rotational speed of the crankshaft.

The intake valve 3 is driven to open and close by the intake side valve member, and the exhaust valve 4 is driven to open and close by the exhaust side valve member, and a similar lubrication device is provided. Mainly explained.
As shown in FIG. 1, the exhaust valve 4 that opens and closes the exhaust port 10 of the combustion chamber C has a valve stem 402 supported on the upper deck 11 side through a valve guide 16 so as to be slidable in the longitudinal direction of the stem. The stem end 401 at the projecting end of the exhaust valve 4 is covered with an inverted cup-shaped tappet 5 and abuts against a boss portion 502 protruding from the inner wall of the top wall 501 of the tappet 5. The tappet 5 has a cylindrical portion 503 slidably supported along a guide hole 19 formed in the guide portion 18 protruding from the upper deck 11 and the side wall 17 side in the cylinder head 2.

  The cam surface of the exhaust cam 7 that rotates integrally with the exhaust cam shaft 14 slidably contacts the upper surface ft of the top wall 501 of the tappet 5. Moreover, the sliding contact area E with the cam surface of the top wall 501 of the tappet 5 has a circular shape as the tappet 5 rotates about the tappet center line (here, coincides with the valve center line L) (FIG. 4). (Refer to (a)), a through hole 23 is formed in a region facing the oil reservoir 22 which will be described later. The through-hole 23 forms an oil passage through which oil falling from above can be introduced into the tappet 5 and dropped into the oil reservoir 22, and is formed here. Two or more may be formed.

  The exhaust valve 4 opens and closes the exhaust port 10 by its umbrella portion 403. The stem end 401 of the exhaust valve 4 is formed so as to receive the urging force Fc of the spring 24 in the valve closing direction via the retainer 25 and the cotter 26. That is, an annular concave groove 27 is formed in the vicinity of the stem end 401, and a cotter 26 that is split in two along the valve shaft direction is fitted into the groove. Both the cotters 26 are formed so that their outer peripheral surfaces are tapered surfaces fk by fitting into the annular concave grooves 27. The taper surface fk can be engaged with the taper hole 251 at the center of the retainer 25, so that the retainer 25 can be locked to the annular groove 27 via the cotter 26.

  Here, the retainer 25 is formed of an aluminum alloy in order to reduce the weight. As shown in FIGS. 1, 3, and 4 (b), the retainer 25 has a disc-shaped main portion 252 with a tapered hole 251 formed on the lower surface of the outer peripheral edge of the main portion 252 and the upper end of the spring 24. And an annular flange 254 extending upward from the outer peripheral edge of the main portion.

  The lower end of the spring 24 that applies an urging force Fc in the valve closing direction to the exhaust valve 4 via the annular spring receiving portion 253 is in contact with a spring receiving portion 28 formed on the upper deck 11 side. As shown in FIG. 1, oil scatters and falls on the spring receiving portion 28 and the upper deck 11 in the vicinity thereof. These oils stay in the depression d, and are scattered around the exhaust valve 4 due to vibration of the engine 1 or the like.

  As shown in FIGS. 3 and 4B, the main portion 252 of the retainer 25 has a round plate shape with its upper surface and the annular flange portion 254, and forms an oil sump 22 that opens upward. When the valve has a tilt angle α, the oil level fo is accommodated in an inclined manner with respect to the upper surface of the main portion 252 of the retainer 25, so that the oil amount of the oil reservoir 22 is equal to the capacity of the oil reservoir 22. Considering this point, the height h of the annular flange portion 254 is set. Further, as shown in FIGS. 5A and 5B, the retainer 25a is provided with a notch g in a part of the annular flange portion 254a, and the height h1 of the flange portion is lowered to adjust the weight. It may be.

  As shown in FIG. 3, the diameter d0 of the main portion 252 of the retainer 25 is formed smaller than the inner diameter D1 of the cylindrical portion 503 of the tappet 5, and an annular gap S is secured between them. This annular gap S facilitates the intrusion of scattered oil from the upper deck 11 and the spring receiving portion 28 into the tappet inner top space Et between the retainer 25 and the top wall 501 of the tappet 5. This contributes to the supply of lubricating oil to the opposing sliding contact portion.

The oil reservoir 22 on the upper surface of the retainer 25 is opposed to the inner wall surface of the top wall 501 of the tappet 5 at a predetermined interval, and oil that is scattered from below or from the side of the tappet inner top space Et, The oil falling from the through hole 23 can be received.
The engine 1 in FIGS. 1 and 2 is provided with a valve-operated lubrication device on the exhaust valve 4 as described above, but there is also a lubrication device having a structure close to left and right symmetry on the intake valve 3 side. Although it is attached, a duplicate description is omitted here.

  When the above-described engine 1 is driven, suction is performed by driving the direct-acting valve operating device, and the exhaust valves 3 and 4 are sucked in a rotation region where only the urging force Fc of each spring 24 is received, the exhaust port 10 is closed, and each spring 24 is closed. The suction and exhaust ports 9 and 10 are opened in the rotational range where the suction and the exhaust cams 6 and 7 receive the pressing force Fo against the urging force Fc. When the intake and exhaust ports 9 and 10 are opened and closed at an appropriate rotation timing, each combustion chamber C of the engine 1 executes a predetermined combustion cycle to generate an output.

  When such an engine 1 is driven, it is sucked from an oil circulation system (not shown), and oil is constantly supplied to the exhaust camshafts 13 and 14, and the supplied oil falls to the upper deck 11 and is not shown. It flows to the oil flow down side. At this time, the oil stays in the spring receiving portion 28 and the other recessed portion d of the other portion, and a part of the staying oil scatters in the tappet 5 due to the influence of the engine vibration, the spring 24 operation, and the like. Through the top space Et in the tappet and reaches the oil reservoir 22 of the retainer 25. Oil that passes through the through hole 23 of the tappet 5 also flows into the oil reservoir 22, and relatively sufficient oil is always held. For this reason, the oil reservoir 22 can easily supply the accumulated oil to the clearance t between the contact portions of the stem end 401 and the tappet 5 side boss portion 502 and improve the lubrication of the contact portions. Excessive wear due to insufficient lubrication in the same part can be suppressed.

  In particular, the valve system of the engine shown in FIGS. 1 and 2 is a direct-acting valve operating device, and the reverse cup-shaped tappet 5 is used in spite of the relatively small amount of oil scattered near the stem end 401. In the lubricating device of the invention, oil that has been splashed into the top space Et in the tappet above the retainer 25 or oil that has passed through the through-hole 23 is received by the oil reservoir 22, so that it is difficult to fall down. The oil accumulated in 22 can be sufficiently scattered and supplied to the gap t between the stem ends 301 and 401 and the boss portion 502 of the tappet 5 according to the vertical movement of the retainer 25 and the tappet 5. Even so, it is possible to improve the lubrication of the mutual contact portions and to suppress wear.

  As described above, the tappet 5 has the through-hole 23 formed in the top wall 501 so as to secure a sufficient amount of oil supply to the oil reservoir 22 of the retainer 25. If the engine 1 has a large amount of scattered oil reaching 22, the through hole may be excluded. Further, the through-hole 23 in the top wall 501 of the tappet 5 may be eliminated, and an oil jet device (not shown) may be disposed in the vicinity of the spring receiving portion 28 to ensure the amount of oil supplied to the oil reservoir 22. In this case, the oil jet device can be reduced in size by suppressing the fall of the oil from the tappet inner space Et as compared with the case where a conventional retainer having no oil reservoir is used.

  In the above description, the oil sump 22 is formed by the annular flange portion 254 extending upward from the outer peripheral edge of the retainer 25. However, as shown in FIG. 6, the main body 252b of the retainer 25b is shaped like a mortar-shaped upward surface fn. The oil reservoir 22b may be formed there, and in this case, the same operation and effect as the retainer 25 of FIG. 1 can be obtained.

  Although the present invention has been described as being applied to a direct-acting valve operating apparatus, an engine including a valve operating apparatus of a type that includes a tappet and another valve operating member is interposed between the tappet and the cam. The present invention is equally applicable.

1 is a cutaway cross-sectional view of a main part of a cylinder head of an engine equipped with an engine valve system lubrication device as one embodiment of the present invention. It is a schematic block diagram of the engine provided with the lubricating device of the engine valve system of FIG. It is a principal part notch expanded sectional view of the tappet and retainer used with the engine valve operating system of FIG. The tappet and retainer retainer used with the engine valve system of FIG. 1 are shown, (a) is an enlarged plan view of the tappet, and (b) is an enlarged plan view of the retainer. The modification of the retainer used with the engine valve system of FIG. 1 is shown, (a) is a side view of a modification retainer, (b) is a top view. It is a side view of the other modification of the retainer used with the engine valve operating system of FIG. It is a principal part notched sectional view of the cylinder head with which the conventional direct acting type valve gear apparatus was mounted | worn.

Explanation of symbols

1 Engine 2 Cylinder head 4 Valve (exhaust valve)
5 Tappet 501 Top wall 22 Oil reservoir 23 Through hole 25 Retainer 254 Annular flange c Combustion chamber Fo Pressing force

Claims (3)

A valve supported by the cylinder head for opening and closing the combustion chamber, a retainer mounted near the stem end of the valve, a tappet slidably supported in the cylinder head, and the valve via the top wall of the tappet In a lubricating system for an engine valve system having a cam for applying a pressing force in the opening direction,
An engine valve system lubrication device, wherein an oil reservoir is formed on an upward surface of the retainer. The lubrication device for an engine valve system according to claim 1,
A lubrication device for an engine valve operating system, wherein a top hole of the tappet is formed with a through hole facing the oil reservoir. The lubrication device for an engine valve operating system according to claim 1 or 2,
The oil valve lubricating system according to claim 1, wherein the oil reservoir is formed of a flange portion extending upward from an outer peripheral edge of the retainer.

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