JP4540116B2 - Valve mechanism - Google Patents

Description

  The present invention relates to an OHV type (overhead valve type) valve operating mechanism in which two valves are simultaneously operated by a single rocker arm via a bridge.

FIG. 18 shows a conventional OHV type (overhead valve type) valve operating mechanism in which two valves are operated simultaneously by one rocker arm. Reference numeral 1A denotes the entire engine. A cylinder block 45 surrounds a cylinder 47 which is bored in a vertical shape. A cylinder head 40 is attached to the upper portion of the cylinder block 45.

Two valves 20A and 20A are attached to the cylinder head 40 so as to be movable up and down.
The bridges 17A straddle the upper portions of the two valves 20A and 20A, and thus the two valves 20A and 20A are configured to move up and down together.

A plug-like pressing portion 15A is fitted to the center portion of the bridge 17A. The pressing portion 15A is pressed so as to operate up and down by rocking of the rocker arm 8A.
A support portion 17F extending downward in the vertical direction is formed at the lower center portion of the bridge 17A.
A pin 19A fixed to the cylinder head 40 is loosely fitted in the inner hole of the support portion 17F.

A horizontal force S applied to the pressing portion 15A is received by the pin 19A.
A dove-shaped rocker arm 8A is disposed on the bridge 17A.
The rocker arm 8A is rotatably supported by the rocker shaft 6 at a substantially central portion in the left-right direction in FIG.

  An arc-shaped pressing surface 13A is formed below the valve side end portion 11A of the rocker arm 8A. An oil hole (shown by a dotted line) that leads from the pressing surface 13A to the rocker shaft 6 is formed to reduce friction between the pressing surface 13A and the pressing portion 15A.

The adjusting screw 4 is screwed to the end 9 on the push rod 2 side of the rocker arm 8A.
The adjusting screw 4 has a function of adjusting a predetermined maximum gap (valve clearance) between the pressing surfaces 13A to 15A.

  The lower end portion of the adjusting screw 4 has a spherical convex contact surface, and is in sliding contact with the spherical concave contact surface provided at the upper end portion of the push rod 2. The lower end of the push rod 2 is in contact with a cam shaft (not shown). The camshaft rotates in synchronization with the crankshaft.

In the above structure, the contact portion P of the pressing surface 13A to the pressing portion 15A is a line extending perpendicular to the paper surface. Since the contact point P is a line contact, the contact point P contacts at a high pressure. Accordingly, the pressing surface 13A and the pressing portion 15A are required to be expensive wear-resistant materials. In particular, the material of the bridge 8A having the pressing surface 13A has to be expensive such as a sintered material.
Further, since the pressing surface 13A has an arc shape, the swing range between the pressing surface 13A and the pressing portion 15A is wide, and the support by the pin 19A is required. This causes a complicated shape of the bridge 17A, an increase in the number of weight-increasing parts, and an increase in cost due to these. .

FIG. 19 shows another prior art proposed for solving the problems in the structure of FIG.
An adjusting screw 5B is provided at the valve side end of the rocker arm 8B.
A spherical convex contact surface 5C is provided at the lower end of the adjustment screw 5B.

A cap-like member 16B surrounding the spherical convex contact surface 5C is slidably fitted to the spherical convex contact surface 5C by the spherical concave contact surface 16C.
The lower surface of the cap-shaped member 16B is formed flat.
The upper surface 17C of the bridge 17B is formed flat in the horizontal direction.

A spherical concave contact surface 9C is formed below the push rod side end portion 9B of the rocker arm 8B. A spherical convex contact surface 3B corresponding to the spherical concave contact surface 9C is formed at the upper end of the push rod 3.
The spherical concave contact surface 9C and the spherical convex contact surface 3B are slidably in contact with each other.

The configuration shown in FIG. 19 has an advantage that an expensive material is not required because the spherical convex contact surface 5C of the adjusting screw 5B comes into surface contact with the spherical concave contact surface 16C. Further, since the lower surface of the cap-like member 16B and the upper surface 17C of the bridge 17B are in surface contact, there is an advantage that the rocking range of the rocker arm 8B is narrowed and the support by the pin 19A is not required.
However, in the structure of FIG. 19, it is difficult to machine the spherical concave contact surface 9C formed at the lower part of the push rod side end portion 9B of the rocker arm 8B. And there existed the subject that the difficulty of the process of the surface 9C would be connected directly to the cost increase.

As for a valve operating mechanism of an engine, a technique related to a rocker arm of an OHC internal combustion engine is disclosed (for example, see Patent Document 1). However, this technique does not solve the problems and problems described above.
Japanese Utility Model Publication No. 6-22504

The present invention has been proposed in view of the problems of the prior art as described above, and has a first object to provide an inexpensive valve mechanism that does not use an expensive material for the rocker arm.
A second object is to provide an inexpensive valve mechanism that does not require a pin for suppressing the swinging of the bridge.

  According to the present invention, there is provided a bridge mechanism (17) straddling the upper ends of two valves (20, 20), and a valve operating mechanism that is operated simultaneously by one rocker arm (8), wherein the rocker arm (8) is pushed. The adjustment screw (4) is screwed to the rod side end (9), and the spherical convex surface portion (5a) at the lower end of the adjustment screw (4) is joined to the spherical concave surface portion (2a) at the upper end of the push rod (3). The valve-side end (10) of the rocker arm (8) is connected to the bridge (18) via a spherical protrusion (18) and a cap-like member (16) fitted over the spherical convex surface so as to be swingable. 17) In the OHV type valve operating mechanism that is operated by pressing, the spherical protrusion (18) is integrally formed at the upper end of the neck (29) at the center of the upper surface of the bridge (17), and the spherical protrusion ( 18) The plug-shaped member (16) has a cylindrical outer shape, and its upper surface (16a) abuts on the pressing surface (13) of the rocker arm valve side end (10), and the pressing surface (13) is formed flat in a substantially horizontal direction. Oil holes (8a, 8b) communicating with the rocker shaft hole (8i) are opened in the pressing surface (13), and a groove (16g) is formed in the lower end portion in the cap-like member (16). ) And a C-shaped clip (C) is attached to prevent the cap-shaped member (16) from falling off from the spherical protrusion (18).

  The adjusting screw in the above is a screw member for adjusting the valve clearance. The drop-off prevention tool is preferably a so-called C (sir) clip that can be easily attached and detached.

  A conical hole (8c) having a wide lower surface communicating with the oil hole (8b) in the rocker arm is provided on the pressing surface (13) of the valve side end (10) of the rocker arm (8).

  Further, according to the present invention, there is provided a valve mechanism that is provided with a bridge (17) straddling the upper ends of the two valves (20, 20) and is simultaneously operated by one rocker arm (8), wherein the rocker arm (8) An adjustment screw (4) is screwed onto the push rod side end (9) of the screw rod, and the spherical convex surface portion (5a) at the lower end of the adjustment screw (4) is connected to the spherical concave surface portion (2a) at the upper end of the push rod (3). The valve-side end (10) of the rocker arm (8) is joined via a spherical protrusion (18) and a cap-like member (16) fitted over the spherical convex surface so as to be swingable. In the OHV type valve operating mechanism that operates by pressing the bridge (17), the spherical protrusion (18) is integrally formed on the upper end of the neck (29) at the center of the upper surface of the bridge (17). Before covering the protrusion (18) The cap-shaped member (16) has a cylindrical outer shape, and its upper surface (16a) abuts on the pressing surface (13) of the rocker arm valve side end (10), and the pressing surface (13) is formed flat in a substantially horizontal direction. In addition, an oil hole (8a, 8b) communicating with the rocker shaft hole (8i) is opened in the pressing surface (13), and a V-shaped groove (lower surface extending to the oil hole (8b) is wide) 8d), a groove (16g) is provided at the lower end of the cap-shaped member (16), and a C-shaped clip (C) is attached to the spherical protrusion (18) of the cap-shaped member (16). Prevents falling off.

  And according to this invention, it is a valve operating mechanism which provides a bridge (17) straddling the upper end of two valves (20, 20), and operates simultaneously by one rocker arm (8), Comprising: Said rocker arm (8) An adjustment screw (4) is screwed onto the push rod side end (9) of the screw rod, and the spherical convex surface portion (5a) at the lower end of the adjustment screw (4) is connected to the spherical concave surface portion (2a) at the upper end of the push rod (3). The valve-side end (10) of the rocker arm (8) is joined via a spherical protrusion (18B) and a cap-like member (16B) fitted over the spherical convex surface so as to be swingable. In the OHV type valve operating mechanism that operates by pressing the bridge (17), the spherical protrusion (18B) is formed integrally with the upper end of the neck (29) at the center of the upper surface of the bridge (17). (18B) The cap portion (16B) covering the spherical protrusion (18) is formed in a cylindrical shape and the upper surface (16a) is pressed against the rocker arm valve side end (10). The pressure surface (13) is in contact with the surface (13), the flat surface is formed in a substantially horizontal direction, and the pressure surface (13) has oil holes (8a, 8b) communicating with the rocker shaft hole (8i). Is formed, and an oil reservoir (24) is formed between the horizontal portion (18s) of the top of the spherical protrusion (18B) and the inner surface (16J) of the cap-shaped member, and the cap-shaped member (18B) An oil hole (26) is perforated at the top, and a groove (16g) is provided at the lower end of the cap-like member (16B), and a C-shaped clip (C) is attached to the spherical protrusion ( 18B) is prevented from falling off That.

  A taper (23) is provided that opens in the direction opposite to the push rod side (9) of the pressing surface (13) of the valve side end (10) of the rocker arm (8).

  Further, according to the present invention, there is provided a valve operating mechanism that is provided with a bridge (17D) straddling the upper ends of the two valves (20, 20) and is simultaneously operated by one rocker arm (8), wherein the rocker arm (8) An adjustment screw (4) is screwed onto the push rod side end (9) of the screw rod, and the spherical convex surface portion (5a) at the lower end of the adjustment screw (4) is connected to the spherical concave surface portion (2a) at the upper end of the push rod (3). The valve-side end (10) of the rocker arm (8) is joined via a spherical protrusion (50) and a cap-like member (16) fitted over the spherical convex surface so as to be swingable. In the OHV type valve operating mechanism that operates by pressing the bridge (17D), the spherical protrusion (50) is formed separately from the bridge (17D) and extends the neck at the center of the upper surface of the bridge (17D). Leg (5 ) Is fixed, and the cap-like member (16) covering the spherical protrusion (50) is cylindrical in shape, and its upper surface (16a) is in contact with the pressing surface (13) of the rocker arm valve side end (10), The pressing surface (13) is formed substantially flat in the horizontal direction, and the pressing surface (13) is provided with oil holes (8a, 8b) communicating with the rocker shaft hole (8i), and the cap A groove (16g) is provided at the lower end of the inner member (16) and a C-shaped clip (C) is attached to prevent the cap-like member (16) from falling off from the spherical protrusion (50).

According to the present invention described above, since the pressing surface (13) that is flat in the horizontal direction is formed in the lower part of the valve side end portion of the rocker arm (Claim 1), the force applied to the pressing surface of the rocker arm and the bridge side is Surface contact.
Therefore, compared to the line contact of the prior art, the force applied to the pressing surface of the rocker arm and the bridge side is a low pressure, and it is not necessary to use an expensive material such as a sintered alloy for the member used on the bridge side. it can.

In addition, since a spherical protrusion is provided on the upper part of the bridge, and a cap-like member that covers the protrusion is fitted on the upper part of the protrusion so as to be swingable (Claim 1), the conventional cap is attached in the reverse direction. It is hard to drop off compared to things.
The rocker arm is swung by the cap-shaped member, and the pressing force from the rocker arm is applied to the protrusion. Therefore, a force is easily applied to the center of the bridge, and a pin for receiving the horizontal swing required in the prior art becomes unnecessary.

  In addition, a cap-off preventer for preventing the cap-like member from falling off is attached to the lower end portion inside the cap-like member covering the protrusion (Claim 1), so that the cap-like member is assembled, maintained or operated. Will not come off.

  In the present invention, if a conical hole having a wide lower surface communicating with the oil hole in the rocker arm is provided on the pressing surface of the rocker arm (Claim 2), the lubricating surface between the pressing surface of the rocker arm and the upper surface of the cap-shaped member is formed widely. Thus, burn-in damage does not occur.

  Further, in the present invention, if a V-shaped groove having a wide lower surface communicating with the oil hole in the rocker arm is provided on the pressing surface of the rocker arm (Claim 3), the lubricating surface is further widened and seizure damage occurs. There is nothing.

  In addition, in the present invention, if the taper 23 that opens in the direction opposite to the rocker shaft is provided on the pressing surface of the rocker arm 8, a searcher (gap gauge) for adjusting the valve clearance can be easily inserted. .

Embodiments of the present invention will be described below with reference to the accompanying drawings.
A first embodiment of the valve operating mechanism of the present invention is shown in FIGS.
In FIG. 1, a cylinder block 45 surrounds a cylinder 47 bored in a vertical shape as indicated by a one-dot chain line. A cylinder head 40 is attached to the upper portion of the cylinder block 45.

Two valves 20 and 20 are attached to the cylinder head 40 by being biased by a coil spring (not shown).
The upper parts of the two valves 20 and 20 are configured to be fitted in fitting holes provided in the bridge 17 so as to move up and down together.

2 and 3, the bridge 17 is formed in an outer shape similar to the conventional bridge 17B of FIG. 19 except for the vicinity of the protrusion.
The whole is formed in a quadrangular prism shape surrounded by a flat bottom surface 31, a shoulder portion 27 parallel to the bottom surface 31, and parallel side surfaces 32 and 32. The end portion of the shoulder portion 27 is formed in a shoulder shape by the inclined portion 30.

A spherical protrusion 18 having a neck portion 29 is provided on the upper center portion of the shoulder portion 27.
The lower end portion of the neck portion 29 is fixed to a recessed portion 28 that is slightly lower than the shoulder portion 27. A spherical protrusion 18 is formed on the upper end of the neck portion 29.

Referring also to FIG. 1, the upper portion of the protrusion 18 is disposed so as to cover the cap-shaped member 16.
The cap-shaped member 16 has a flat upper surface 16a and is formed in a cylindrical cap shape. Inside the cap-shaped member 16, a hole portion 16 e is formed with a spherical concave contact surface 16 i slidable in close contact with the protrusion 18.

  A groove 16g is formed at the lower end of the hole 16e over the circumference. The groove 16g is configured such that a C-shaped clip C which is a drop-off preventing tool is fitted therein. The inner diameter of the C-shaped clip C fitted into the cap-shaped member 16 is smaller than the outer diameter of the spherical protrusion 18 so that the spherical protrusion 18 will not drop out.

Returning to FIG. 1, a dove-shaped rocker arm 8 is disposed on the top of the cap-shaped member 16.
The rocker arm 8 is rotatably supported by a rocker shaft 6 at a substantially central portion in the left-right direction in FIG.

A horizontal and flat pressing surface 13 is formed below the valve-side end portion 10 of the rocker arm 8.
The pressing surface 13 is disposed and formed at a position facing the upper surface 16 a of the cap-shaped member 16.
The rocker arm 8 is formed with oil holes 8 b and 8 a (shown by dotted lines) that lead from the pressing surface 13 to the rocker shaft 6.

The oil hole 8 a is in contact with the rocker shaft 6 and communicates outward through the valve side end 10. The oil hole 8 b is branched from the oil hole 8 a and communicates with the central portion of the pressing surface 13.
The lubricating oil guided from the oil hole 8b reduces the friction between the pressing surface 13 and the upper surface 16a of the cap-shaped member 16. The friction is generated as the valves 20 and 20 move up and down.

An adjusting screw 4 is screwed to an end 9 on the push rod 2 side of the rocker arm 8.
The adjusting screw 4 has a function of adjusting a predetermined maximum gap (valve clearance) between the pressing surface 13 and the upper surface 16 a of the cap-shaped member 16.

  The lower end portion of the adjusting screw 4 is a spherical convex contact surface 5a, and is in sliding contact with the spherical concave contact surface 2a provided at the upper end portion of the push rod 2. The lower end of the push rod 2 is in contact with a cam shaft (not shown). The camshaft rotates in synchronization with a crankshaft (not shown).

  In the above structure, when the engine is operated, the push rod 2 moves up and down by the cam shaft rotating in synchronization with the crankshaft, and the rocker arm 8 is swung around the rocker shaft 6.

As the rocker arm 8 swings, the pressing surface 13 contacts and presses the upper surface 16 a of the cap-shaped member 16. The contact between the pressing surface 13 and the upper surface 16a becomes surface contact, and the surface pressure decreases. In the prior art, it is not necessary to take measures against wear due to the line contact on the pressing side.
When the pressing surface 13 contacts and presses the upper surface 16a, the lubricating oil that has passed through the oil holes 8a and 8b is guided to the contact surface to reduce sliding friction.

  Accordingly, the pressure reduction due to the surface contact of the pressing surface 13 and the absence of a breakage of the lubricating oil film guided to the contact surface reduce the wear of the pressing surface 13 and the upper surface 16a, thereby reducing the service life. Is extended. For example, the sliding contact surfaces of the pressing surface 13 and the upper surface 16a need not be made of a sintered alloy or other expensive material.

The pressing of the pressing surface 13 to the cap-shaped member 16 presses the spherical protrusion 18 of the bridge 17.
Then, the valves 20 and 20 are operated together with the bridge 17.

  Here, the movement of the cap-shaped member 16 falling off from the spherical protrusion 18 due to the vertical movement and swinging of the cap-shaped member 16 is because the cap-shaped member 16 is fitted onto the protrusion 18, so Compared with the fact that the opening is attached with the opening facing upward, the member is less likely to fall off. Also, the C-shaped clip C prevents the dropout.

4 and 5 show a second embodiment.
A feature of the second embodiment is a configuration that reduces sliding friction between the pressing surface 13 of the rocker arm 8 and the upper surface 16a of the cap-shaped member 16 in the first embodiment.
In the following description, parts different from the first embodiment will be mainly described, and the same portions as those in the first embodiment will be omitted.

  4 and 5 showing the lubrication site, which is a feature of the second embodiment, a conical hole 8c in which the lower surface of the rocker arm 8 expands is provided. The central part of the conical hole 8c communicates with the oil hole 8b. The oil hole 8b communicates with the oil hole 8a, and the oil hole 8a communicates with an oil passage (not shown) of the rocker shaft 6.

FIG. 6 shows a state in which the pressing surface 13 is viewed from the lower side of CC.
During engine operation, the lubricating oil that has reached the oil hole 8b from the oil hole 8a spreads to the pressing surface 13 through the conical hole 8c, and takes away the amount of heat proportional to the amount of oil between the upper surface 16a of the cap-like member 16. Reduces sliding friction.
It should be noted that sufficient consideration is required in the implementation so that the contact surface pressure of the pressing surface 13 does not increase due to the conical hole 8c.

7 and 8 show another example of the second embodiment.
A groove 8d having a V-shaped cross section is provided at the lower end portion of the oil hole 8b that leads to the rocker shaft 6 and reaches the pressing surface 13. In the example of FIG. 7, the grooves 8d are parallel to the oil holes 8a, but they may be orthogonal or crossed. The examples of FIGS. 7 and 8 reduce the sliding friction more than the examples of FIGS. 4 and 5 by the amount of dispersion of the lubricating oil. However, more careful consideration is required to reduce the contact area.

9 and 10 show still another example of the second embodiment.
A groove 8d and a groove 8e having a V-shaped cross section with the oil hole 8b as a center are provided in a cross shape at the lower end of the oil hole 8b reaching the pressing surface 13 through the rocker shaft 6. In the example of FIG. 9, the groove 8d is parallel to the oil hole 8a, but may be orthogonal or crossed. The cross may be X-shaped. In the examples of FIGS. 9 and 10, the sliding friction is reduced by the amount of dispersion of the lubricating oil more than the examples of FIGS. 7 and 8. However, more sufficient consideration is necessary for the reduction of the contact area.

11 to 13 show a third embodiment.
In the second embodiment, sliding friction between the pressing surface 13 and the upper surface 16a of the cap-shaped member 16 is reduced. On the other hand, in the third embodiment, the sliding friction between the cap-like member 16 and the spherical protrusion 18 provided on the upper portion of the bridge 17 is reduced.
In the following description, parts different from the first embodiment will be mainly described, and the same portions as those in the first embodiment will be omitted.

  The following description will be made with a different part from the embodiment of FIGS. 1 and 2 used in the first embodiment as a main component, omitting the same other portions as those of the first embodiment.

With reference to FIG.11 and FIG.12, the cap-shaped member 16B is arrange | positioned so that the upper part of protrusion 18B may be covered.
The cap-shaped member 16B is formed in a cylindrical cap shape having a flat upper surface 16A. A hole 16E is formed inside the cap-shaped member 16B. A spherical concave contact surface 16J is formed on the top of the hole 16E. The concave contact surface 16J is slidable in close contact with the protrusion 18B.

  An oil hole 26 communicating from the upper surface 16A to the hole 16E is provided at a position facing the oil hole 8b. Since the oil hole 8b is normally provided toward the center of the upper surface 16A, the oil hole 26 is located near the center of the protrusion 18B.

A horizontal portion 18s is formed horizontally on the top of the protrusion 18B.
As a result of the above configuration, an oil reservoir 24 having a function of an oil reservoir is formed between the horizontal portion 18s at the top of the protrusion 18B and the spherical concave contact surface 16J inside the cap-shaped member 16B.

During engine operation, the lubricating oil that has reached the oil hole 8b from the oil hole 8a flows out from the lower end of the oil hole 8b onto the upper surface 16A of the cap-shaped member 16B. The lubricating oil on the upper surface 16A passes through the oil hole 26 and stays in the oil reservoir 24, and reduces sliding friction between the spherical concave contact surface 16J and the protrusion 18B.
With the above configuration, even when the lubricating oil path indicated by the symbol W in FIG. 12 does not work effectively, the lubricating oil is supplied to reduce the sliding friction between the spherical concave contact surface 16J and the protrusion 18B. be able to.

FIG. 13 shows the swinging of the cap-shaped member 16B that occurs at the time of sliding contact between the spherical concave contact surface 16J and the protrusion 18B.
In FIG. 13, a solid line indicates a left-tilt state, and a dotted line indicates a right-tilt state.
In either case of leftward tilting or rightward tilting, the oil hole 26 is in the upper part of the oil reservoir 24 so that the supply of the lubricating oil from the upper surface 16A of the cap-like member 16B to the oil reservoir 24 is not continued. Since the inclination of the cap-shaped member 16B in FIG. 13 is greater than or equal to the entity, the entity is further safer.

14 and 15 show a fourth embodiment.
The feature of the fourth embodiment is a configuration for easily adjusting the valve clearance between the pressing surface 13 of the rocker arm 8 and the upper surface 16a of the cap-shaped member 16.
The adjustment of the valve clearance is performed in the actual machine and in the warm-up operation state, which is a troublesome and delicate work. In adjusting the valve clearance, the searcher 35 can be easily inserted between the pressing surface 13 and the upper surface 16a.

In the following description, portions different from those in FIGS. 1 and 2 used in the first embodiment will be mainly described, and the same portions as those in the first embodiment will be omitted.
In FIG. 14, a taper portion 23 is provided on the pressing surface 13 of the rocker arm 8. The taper 23 is grooved on the left side in FIG. 24, that is, on the side opposite to the rocker shaft 6.
The tapered portion 23 is configured so that the gap measuring portion 36 of the searcher 35 can be easily inserted between the pressing surface 13 and the upper surface 16a of the cap-like member 16, and the valve clearance can be easily adjusted.
Reference numeral 25 denotes a tapered portion provided at an end portion of the upper surface 16a, and contributes to valve clearance adjustment in combination with the tapered portion 23. The tapered portion 23 may be a gentle arc.

FIG. 15 is an explanatory diagram for illustrating the function and effect of the taper portion 23 described above.
In FIG. 15, the clearance between the pressing surface 13 of the rocker arm 8 and the upper surface 16a of the cap-shaped member 16, that is, the valve clearance v is adjusted.
The adjust screw 4 provided at the push rod side end 9 is used to determine whether or not the gap measuring portion 36 (hereinafter abbreviated as the searcher 35) of the searcher 35 having the gap measuring portion 36 having the same thickness as the valve clearance v is inserted. Turn to adjust while gradually increasing the valve clearance v.

The adjustment of the adjustment screw 4 is performed by slightly rotating the screw head Hs while the nut N is loosened.
A valve clearance v into which the searcher 35 can be inserted is obtained by adjusting the rotation of the adjusting screw 4. The minimum gap that can be inserted is a predetermined valve clearance v value.

  In the above operation, when the searcher 35 is inserted into the gap between the pressing surface 13 of the rocker arm 8 and the upper surface 16a of the cap-shaped member 16, the groove by the tapered portion 23 serves as a guide to facilitate the insertion of the searcher 35. This makes it easy to adjust the troublesome valve clearance v.

16 and 17 show a fifth embodiment.
The feature of the fifth embodiment relates to the structure of the bridge 8. The bridge 8 has an integral structure in which the protrusion 18 protrudes from the upper portion of the shoulder portion 27.

In order to achieve such an integrated structure, there are restrictions on equipment for manufacturing and processing. For example, a cold forging facility and a processing facility for forming the protrusions with an integral structure are necessary, which causes a cost increase.
In order to solve the above-mentioned problem, the fifth embodiment is one in which the protrusion is separated and joined to the bridge body.

In the following description, portions different from those in FIGS. 1 and 2 used in the first embodiment will be mainly described, and the same portions as those in the first embodiment will be omitted.
In FIG. 16, a protrusion body 50 is fitted and integrated with a bridge body 17D of the bridge.
The protrusion 50 is substantially the same as the shape in which the neck portion 29 (FIGS. 2 and 3) of the protrusion 18 is elongated.

That is, in the protrusion 50, a leg 54 corresponding to the neck is formed below the spherical protrusion 53. The length of the leg portion 54 is a sufficient fitting depth to receive the force applied to the spherical protrusion 53.
The bridge body 17D is provided with a hole 49 for fitting and coupling the protrusion 50.
In order to effectively fit the length of the leg portion 54 of the protrusion 50, in the example of FIG. 16, the second bottom surface portion 42 is protruded downward below the bottom surface portion 41 of the bridge body 17D, The depth of the hole 49 is obtained.

  As described above, since the bridge is manufactured at the two points of the bridge body 17D and the protrusion 50, the manufacturing equipment is not specified and the cost is reduced. In addition, the bridge body and the protrusions can be manufactured in different departments suitable for each, which makes it suitable for mass production.

FIG. 17 shows another example of the fifth embodiment.
In FIG. 17, the protrusion 55 has a threaded portion 57 formed below the spherical protrusion 56. The length of the threaded portion 57 is formed to a length necessary to penetrate the bridge body 17E up and down and fasten with the nut 58.
The bridge body 17E is provided with a screw hole 69 for screwing and fastening the protrusion 55.
The bridge body is completed by screwing and fastening the projecting body 55 to the bridge body 17E.
The effect of having two bridges is the same as the embodiment of FIG.

 In the above two examples, the protrusions are connected to the bridge main body by fitting or screwing, but the protrusions and the bridge main body may be welded.

The side view of 1st Embodiment of the OHV type valve operating mechanism of this invention. The side view which shows the detail of the bridge | bridging used for FIG. The AA arrow directional view of the bridge | bridging of FIG. The side view of 2nd Embodiment. BB sectional drawing of FIG. CC arrow line view of FIG. Another example of FIG. CC arrow line view of FIG. FIG. 7 is still another example diagram of FIG. 6. CC arrow line view of FIG. The side view of 3rd Embodiment. The side view which shows the detail of the bridge | bridging used for FIG. Side view showing the operation of the third embodiment The side view of 4th Embodiment. Explanatory side view showing the operation of the fourth embodiment The side view of 5th Embodiment. The side view of another example of 5th Embodiment. The sectional side view of the conventional OHV valve mechanism. The side sectional view of another example of the conventional OHV valve mechanism.

Explanation of symbols

C ... Drop-off prevention tool, C-type clip 1, 1A ... Engine 2 ... Push rod 4 ... Adjust screw 6 ... Rocker shaft 8 ... Rocker arm 9 ... · Rocker arm push rod side end 10 · · · Rocker arm valve side end 13 · · · Pressing surface 16 · · · Cap-shaped member 16d · · Lower end portion 17 · · · Bridge 18 · · · spherical protrusion 20 ··· · Valve 35 · · · Searcher 36 · · · Spacing portion 40 · · · cylinder head 45 · · · cylinder block 47 · · · cylinder

Claims (6)

A valve operating mechanism that is provided with a bridge (17) across the upper ends of two valves (20, 20) and that is simultaneously operated by one rocker arm (8), wherein the rocker arm (8) has a push rod side end (9 ) Is screwed with an adjusting screw (4), and a spherical convex surface portion (5a) at the lower end of the adjusting screw (4) is joined to a spherical concave surface portion (2a) at the upper end of the push rod (3), and the rocker arm ( 8) The valve-side end (10) presses the bridge (17) through the spherical protrusion (18) and the cap-like member (16) fitted over the spherical convex surface so as to be swingable. In the OHV type valve mechanism to be actuated, the spherical projection (18) is integrally formed at the upper end of the neck (29) at the center of the upper surface of the bridge (17), and the cap covers the spherical projection (18). Shaped member (16 Has a cylindrical shape, and its upper surface (16a) is in contact with the pressing surface (13) of the rocker arm valve side end (10), and the pressing surface (13) is formed substantially flat in the horizontal direction, and The pressing surface (13) is provided with oil holes (8a, 8b) communicating from the rocker shaft hole (8i), and a groove (16g) is provided at the lower end portion in the cap-like member (16) to form a C shape. An OHV type valve operating mechanism characterized in that a clip (C) is attached and the cap-like member (16) is prevented from falling off from the spherical protrusion (18). 2. The conical hole (8 c) according to claim 1, wherein the pressure surface (13) of the valve-side end (10) of the rocker arm (8) is provided with a conical hole (8 c) having a wide lower surface communicating with the oil hole (8 b) in the rocker arm. OHV type valve mechanism. A valve operating mechanism that is provided with a bridge (17) across the upper ends of two valves (20, 20) and that is simultaneously operated by one rocker arm (8), wherein the rocker arm (8) has a push rod side end (9 ) Is screwed with an adjusting screw (4), and a spherical convex surface portion (5a) at the lower end of the adjusting screw (4) is joined to a spherical concave surface portion (2a) at the upper end of the push rod (3), and the rocker arm ( 8) The valve-side end (10) presses the bridge (17) through the spherical protrusion (18) and the cap-like member (16) fitted over the spherical convex surface so as to be swingable. In the OHV type valve mechanism to be actuated, the spherical projection (18) is integrally formed at the upper end of the neck (29) at the center of the upper surface of the bridge (17), and the cap covers the spherical projection (18). Shaped member (16 Has a cylindrical shape, and its upper surface (16a) is in contact with the pressing surface (13) of the rocker arm valve side end (10), and the pressing surface (13) is formed substantially flat in the horizontal direction, and The pressing surface (13) is provided with oil holes (8a, 8b) communicating with the rocker shaft hole (8i), and a V-shaped groove (8d) having a wide lower surface through the oil hole (8b) is provided. In addition, a groove (16g) is provided at the lower end of the cap-shaped member (16) and a C-shaped clip (C) is attached to prevent the cap-shaped member (16) from falling off the spherical protrusion (18). An OHV type valve operating mechanism characterized by that. A valve operating mechanism that is provided with a bridge (17) across the upper ends of two valves (20, 20) and that is simultaneously operated by one rocker arm (8), wherein the rocker arm (8) has a push rod side end (9 ) Is screwed with an adjusting screw (4), and a spherical convex surface portion (5a) at the lower end of the adjusting screw (4) is joined to a spherical concave surface portion (2a) at the upper end of the push rod (3), and the rocker arm ( 8) The valve-side end (10) presses the bridge (17) via the spherical protrusion (18B) and the cap-like member (16B) fitted over the spherical convex surface so as to be swingable. In the OHV type valve mechanism to be operated, the spherical protrusion (18B) is integrally formed at the upper end of the neck (29) at the center of the upper surface of the bridge (17), and the top of the protrusion (18B) is horizontal. Horizontal part (1 s) is formed, and the cap-shaped member (16B) covering the spherical protrusion (18B) is cylindrical in shape, and its upper surface (16a) abuts against the pressing surface (13) of the rocker arm valve side end (10), The pressing surface (13) is formed substantially flat in the horizontal direction, and oil holes (8a, 8b) communicating with the rocker shaft hole (8i) are opened in the pressing surface (13). An oil reservoir (24) is formed between the horizontal portion (18s) of the top of the protrusion (18B) and the inner surface (16J) of the cap-shaped member, and an oil hole (26) is formed on the top of the cap-shaped member (16B). The cap-shaped member (16B) is provided with a groove (16g) at the lower end of the cap-shaped member (16B) and a C-shaped clip (C) is attached to prevent the cap-shaped member (16B) from falling off the spherical protrusion (18B). O characterized by being entangled V Katadoben mechanism. The taper (23) which opens in the reverse direction side with respect to the push rod side (9) of the press surface (13) of the valve side end (10) of the rocker arm (8) is provided. The OHV type valve operating mechanism according to claim 1. A valve operating mechanism that is provided with a bridge (17D) straddling the upper ends of the two valves (20, 20) and is simultaneously operated by one rocker arm (8), wherein the rocker arm (8) has a push rod side end (9 ) Is screwed with an adjusting screw (4), and a spherical convex surface portion (5a) at the lower end of the adjusting screw (4) is joined to a spherical concave surface portion (2a) at the upper end of the push rod (3), and the rocker arm ( 8) the valve side end (10) presses the bridge (17D) through the spherical protrusion (50) and the cap-shaped member (16) fitted over the spherical convex surface and swingably fitted. In the OHV type valve operating mechanism to be operated, the spherical protrusion (50) is formed separately from the bridge (17D), and the leg (29) is extended from the neck (29) at the center of the upper surface of the bridge (17D) ( 54) is stuck The cap-shaped member (16) covering the spherical protrusion (50) has a cylindrical outer shape, and its upper surface (16a) comes into contact with the pressing surface (13) of the rocker arm valve side end (10), and the pressing surface ( 13) is formed substantially flat in the horizontal direction, and the pressing surface (13) is provided with oil holes (8a, 8b) communicating with the rocker shaft hole (8i), and the cap-shaped member (16 ) Is provided with a groove (16g) and a C-shaped clip (C) is attached to prevent the cap-shaped member (16) from falling off the spherical protrusion (50). OHV type valve mechanism.

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