JPH0367007A - Hydraulically operated tappet - Google Patents

Abstract

PURPOSE:To hinder oil return from a low pressure oil chamber when the engine concerned is at a standstill and smoothen the hydraulic tappet function at the time of starting, by furnishing an air bleeder hole at the end of an oil path within a locker arm situated over the low pressure oil chamber to be open at the top of the low pressure oil chamber. CONSTITUTION:A low pressure oil chamber 36 in the same dia. as the inner dia. of a plunger 52 is provided in the position above the bottom surface 34 of a cylinder and at the suction valve side swing end of a locker arm for suction 31. At the same time, the oversurface center of this oil pressure chamber 36 and the tip of an oil path 32 are connected with a minor dia. throttle part 37 in the oil path 32 extension part situated below and an air bleeder hole 38 is formed at the foremost face of the oil path 32. The capacity of the pressure oil chamber 36 in the locker arm 31 is large sufficiently to be equal to the capacity of a pressure oil chamber 59 in the plunger 52. Thus the oil amount in these pressure oil chambers 59, 36 acting in the range from the plunger 52 to inside the locker arm 31 can be maintained sufficiently always. Accordingly a hydraulic tappet 50 embedded in the locker arm 31 over a locker arm for air suction is also equipped with smooth hydraulic tappet function at the time of engine starting.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a hydraulic tappet embedded in the swinging end of a rocker arm on the intake and exhaust valve side, which constitutes a valve operating mechanism of an engine having an inclined cylinder section. In particular, the present invention relates to a structure for ensuring the amount of oil even though the intake/exhaust valve side end of the rocker arm in which the hydraulic tappet is embedded is located above the rocker shaft.

[Prior Art] A tappet body is fitted and fixed in a cylinder formed at the swinging end of a rocker arm on the intake and exhaust valve side, which is swingably supported by a rocker shaft, and a first plunger is slidable inside the tappet body. furthermore, a second plunger is slidably fitted into the first plunger so that the second plunger is always in contact with the bottom surface of the tappet body, and a low pressure oil chamber is formed in the second plunger. A communicating oil hole is formed at the bottom of the tappet body, and an oil reservoir is formed at the swinging end on the intake and exhaust valve side, which the bottom of the tappet body faces.

A hydraulic tappet in which a rocker arm is formed with an oil passage opening in the peripheral wall of the oil reservoir chamber and an air vent opening opening in the top thereof is known from Japanese Utility Model Application Publication No. 61-204903.

By forming the air bleed hole in this way, the air in the oil is removed when starting the engine, etc., and by forming the oil sump chamber as described above, if the cylinder part is upright, Even when the engine is stopped, the amount of oil is ensured to provide smooth hydraulic tappet function when starting.

[Problems to be Solved by the Invention] By the way, in an engine in which the cylinder section is inclined in a V-shape or the like, when an embedded hydraulic tappet is provided at the swinging end of the rocker arm on the intake and exhaust valve side, the intake and exhaust valves are arranged upwardly relative to the rocker shaft. The rocker arm on which the valve side end is located has the following problem when starting the engine.

In other words, since the end of the intake and exhaust valve side is located above the rocker shaft, when the engine is stopped, the oil pump stops and the oil in the oil passage toward the rocker arm's swinging end on the intake and exhaust valve side flows into the oil in the rocker shaft. It passes through the road and returns to the bottom of the engine. Therefore, when starting the engine, it takes time to supply oil to the hydraulic tappets embedded in the intake and exhaust valve side ends located above the rocker shaft.
Smooth hydraulic tappet function during starting cannot be obtained.

Therefore, it is conceivable to provide an oil reservoir as disclosed in the above-mentioned Japanese Utility Model Application No. 61-204903, but since the oil passage is opened in the peripheral wall of the oil reservoir, the intake and exhaust valve side is located above the rocker shaft. In the case of a rocker arm in which the end portion is located, oil tends to return from the oil reservoir to the oil passage when the engine is stopped, and it is not always possible to secure a sufficient amount of oil.

Further, since an oil hole is formed in the bottom of the tappet body to communicate the oil reservoir chamber with the low pressure oil chamber in the second plunger, the problem may occur due to an insufficient amount of oil in the oil reservoir chamber.

There is also the problem of air entrapment from this oil hole, and in addition to the above problem, improvements are awaited from the viewpoint of smoothing the hydraulic tappet function when starting the engine.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to ensure a sufficient amount of oil at all times in a rocker arm in which the hydraulic tappet of the rocker arm is embedded and the end of the intake/exhaust valve side is located above the rocker shaft to ensure smooth engine startup. Our objective is to provide a hydraulic tappet that allows you to obtain the following.

[Means for Solving the Problems] In order to achieve the above-mentioned problems, the present invention forms a cylinder at the swinging end on the intake/exhaust valve side of a rocker arm that is swingably supported by a rocker shaft, and a cylinder is formed in the cylinder at the swinging end on the intake/exhaust valve side. A tappet body fitted in a movable manner, a plunger slidably fitted in the tappet body and always in contact with the bottom surface of the cylinder, a low pressure oil chamber formed in the plunger, and the bottom part of the tappet body and the plunger. The rocker shaft includes a high pressure oil chamber formed between the bottoms, a communication passage formed at the bottom of the plunger to enable communication between the high pressure oil chamber and the low pressure oil chamber, and a check valve provided in the communication passage. An oil passage is formed in the rocker arm from the inside toward the swinging end of the intake and exhaust valve side located above, and the oil passage is connected to the low pressure oil chamber formed in the rocker arm and the plunger located below the oil passage. A hydraulic tappet for supplying oil, wherein an air bleed hole is formed at an end of the oil passage located above the low pressure oil passage, and the oil passage is extended downward so that the oil passage is connected to the low pressure oil passage. It is characterized by opening towards the direction.

Furthermore, the present invention provides an engine in which the cylinder portion is inclined.
The tappet body and the plunger are provided in a cylinder formed at the intake/exhaust valve side end of the rocker arm, which has an oil passage formed therein from the rocker shaft toward the intake/exhaust valve m end located below, and The low-pressure oil chamber in the plunger is directly connected with an oil passage extending from the rocker shaft to the intake and exhaust valve side ends located below, and the oil passages extending upward from the rocker shaft to the intake and exhaust valve side ends. It is also characterized in that the rocker arm on which the section is located is provided with the hydraulic tappet.

[Function] A hydraulic tappet embedded in a cylinder formed at the swinging end of the rocker arm on the intake/exhaust valve side is located above the rocker shaft, and a tappet body is slidably fitted into the cylinder. A low-pressure oil passage is formed between the inside of the plunger, which is slidably fitted in the plunger and is always in contact with the cylinder 33, and the inside of the rocker arm, which is located below the oil passage in the rocker arm. An air vent hole is formed at the end of the oil passage in the rocker arm located above, and the oil passage extends downward and opens upward to the low-pressure oil passage, so when the engine is stopped, the oil passage is closed. Even if the oil in the plunger is returned, only the oil is returned from the low pressure oil chamber formed within the plunger and the rocker arm.

Therefore, a sufficient amount of oil in the low pressure oil chamber is ensured, so
In the hydraulic tappet embedded in the swinging end of the intake and exhaust valve n of the rocker arm located above the rocker shaft,
This provides smooth hydraulic tappet function when starting the engine.

This makes it effective for engines with tilted cylinders.
In that case, a tappet body and a plunger similar to those described above are provided in the cylinder at the intake/exhaust valve side end of the rocker arm, which has an oil passage formed therein from the rocker shaft to the intake/exhaust valve side end located below. It is sufficient to connect the oil passage directly to the low-pressure oil chamber in the plunger, and the hydraulic tappet components can be shared.

[Example] Examples will be described below based on the accompanying drawings.

In FIG. 1 showing the configuration of a valve mechanism for an inclined cylinder part of an engine to which the present invention is applied, l is a cylinder head, 2 is a combustion chamber, 3 is an intake passage, 4 is an exhaust passage, 5 is a head cover, and 6 is a camshaft, 7°8 intake and exhaust cams, 11 intake valve, 13 valve spring, 15
17 is an exhaust valve, 17 is a valve spring, 21 is an intake rocker shaft, 25 is an exhaust rocker shaft, 31 is an intake rocker arm, and 41 is an exhaust rocker arm. In the embodiment, only one cylinder section of a V-type engine is shown, and with respect to the cylinder head 1, it is on the upper right or intake side in the figure and on the lower left or exhaust side in the figure.

An axial oil passage 22 is provided in the double-ended hook shaft 21.25.
26 are formed respectively, and oil is supplied to each oil passage 22, 26 by driving an oil pump (not shown). In addition, oil passages 32.42 are formed in the double-ended hook arms 31.41 toward the swinging ends of the respective intake and exhaust valves. 22 and 26, respectively. Furthermore, a cylinder 3 is installed in each swinging end of the double-ended hook arm 31.41 on the intake and exhaust valve side.
3.43 are formed respectively, and this cylinder 33.4
3 is opened at the lower surface of each rocker arm 31, 41, respectively.

A tappet body 51.61 is slidably fitted into each cylinder 33.43, and the bottom of the tappet body 51.61 is in pressure contact with the head of each intake/exhaust valve stem 12, 16, respectively. .

Furthermore, a plunger 52.62 is slidably fitted within each tappet body 51.61, respectively, and
That is, a built-in hydraulic tabet 50.60 is provided at the swinging end of each intake/exhaust valve side of the double-ended hook arm 31.41.

FIG. 2 shows the hydraulic tappet 50 on the side of the intake valve 11, in which a plunger 52 in the tappet body 51 is brought into contact with the cylinder bottom surface 34 at all times, and the upper end of the plunger 52 has a plurality of radial notches 53. ... is formed. These notches 53... face into the large diameter portion 35 formed on the bottom peripheral wall of the cylinder 33. Furthermore, a communication passage 54 is formed at the bottom of the plunger 52, and this communication passage 5
A check valve 55 with a ball is provided below 4, 56 is a ball cage, and 57 is a plunger printer. A high pressure oil chamber 58 is formed in the bottom of the tappet body 51 by the check valve 55, and a low pressure oil chamber 59 is formed in the plunger 52.

Incidentally, the hydraulic tappet 60 on the exhaust valve 15 side is also composed of similar components, and as shown in FIG.
A similar notch 63 is formed at the upper end of the cylinder 4.
3. A large diameter portion 45 is formed on the bottom peripheral wall. The oil passage 42 opens around this large diameter portion 45 from above.

In the above, the intake rocker arm 31 whose swing end on the intake valve side is located above the intake rocker shaft 21 on the upper right side shown in FIG. 1 is connected to the tip of the oil passage 32 as shown in FIG. A low-pressure oil chamber 36 and a throttle portion 37 extending upward and opening are provided between the cylinder 33 and the upper side of the cylinder 33 .

That is, at the swinging end of the intake rocker arm 31 on the intake valve side, a low-pressure oil chamber 36 having approximately the same diameter as the inner diameter of the plunger 52 is formed upward from the cylinder bottom surface 34, and the center of the upper surface of this low-pressure oil chamber 36 and the oil passage 32 are connected to each other. The tip and the oil passage 32
The oil passages 32 are connected by a small-diameter constricted portion 37 which is a downwardly extending portion of the oil passage 32, and an air vent hole 38 is formed at the distal end surface of the oil passage 32. Here, the low pressure oil chamber 36 in the rocker arm 31
The capacity is sufficiently large and is approximately equal to the capacity of the low pressure oil chamber 59 within the plunger 52 as shown in the figure.

As described above, in the embodiment, in a V-type engine with an inclined cylinder section, hydraulic pressure is embedded in the cylinder 33 at the swinging end on the intake valve side of the intake rocker arm 31 located above the rocker shaft 21. Regarding the tappet 50, a plunger 52 is slidable within a tappet body 51 which is slidable within the cylinder 33 and has a bottom portion that presses against the head of the valve stem 12, and which is in constant contact with the cylinder bottom surface 34. In addition to the low-pressure oil chamber 59, a low-pressure oil chamber 36 located above the low-pressure oil chamber 36 is formed in the rocker arm 31, and a throttle portion is further provided between the low-pressure oil chamber 36 in the rocker arm 31 and the oil passage 32 located above it. 37, even if the oil in the oil passage 32 is returned downward due to the stoppage of the oil pump (not shown) when the engine is running, the oil passage 3
The presence of the downwardly extending portion 2, that is, the throttle portion 37, makes it possible to prevent oil from returning from the low pressure oil chamber 36 within the rocker arm 31.

In this way, the inside of the plunger 52 and the rocker arm 31
In order to ensure a sufficient amount of oil in the low-pressure oil chambers 59 and 36 formed over the inside at all times, the intake rocker arm 31 is embedded in the swinging end on the intake valve side of the intake rocker arm 31 located above the intake rocker shaft 21. Although it is a hydraulic tappet 50,
Smooth hydraulic tappet function can be obtained when starting the engine.

Furthermore, air in the oil is vented through the air vent hole 38 when the engine is started or the like.

And the exhaust rocker arm 4 on the lower left side shown in FIG.
Regarding the hydraulic tappet 60 provided at the swinging end on the exhaust valve side located below the rocker shaft 25 of No. 1, a similar tappet body 61, plunger 62, etc. are provided, and the oil passage 42 is directly connected to the low pressure oil chamber in the plunger 62. Since it is sufficient to connect them, the hydraulic tappet components can be shared.

It should be noted that the present invention is effective not only for V-type engines as in the embodiment, but also for engines in which serial cylinder sections are inclined, and the arrangement of the intake side and exhaust side with respect to the cylinder sections is arbitrary.

[Effects of the Invention] As described above, according to the present invention, the hydraulic tappet embedded in the cylinder at the swinging end of the rocker arm on the intake/exhaust valve side is located above the rocker shaft, and the hydraulic tappet is located above the rocker shaft. Low-pressure oil extends between the plunger, which is slidably fitted in the tappet body and is in constant contact with the bottom of the cylinder, and the rocker arm, which is located below the oil passage in the rocker arm. An air vent hole is formed at the end of an oil passage in the rocker arm located above the low-pressure oil chamber, and the oil passage is extended downward to open above the low-pressure oil chamber. Therefore, even if the oil in the oil passage is returned when the engine is stopped, it is possible to prevent the oil from returning from the low-pressure oil chamber formed between the plunger and the rocker arm, and therefore the oil in the low-pressure oil chamber is By ensuring a sufficient amount at all times, smooth hydraulic tappet function can be obtained when starting the engine.

As described above, as claimed in claim 2, the rocker arm intake valve is particularly effective for engines with inclined cylinder portions, and has an oil passage formed inside the rocker shaft extending from the rocker shaft to the lower end of the intake and exhaust valves. It is sufficient to provide a tappet body and plunger similar to those described above in the cylinder at the end of the exhaust valve, and to connect the oil passage directly to the low-pressure oil chamber in this plunger, so the hydraulic tappet components are shared. be able to.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view of a valve mechanism section showing an inclined cylinder section of an engine to which the present invention is applied, and FIG. 2 is an enlarged vertical cross-sectional view of a hydraulic tappet portion of the present invention. In addition, in the drawing, 21.25 is the rocker shaft, 31.41
32.42 is the rocker arm, 32.42 is the oil passage, 33.43 is the cylinder, 36 is the low pressure oil chamber in the rocker arm, 37 is the downward extension of the oil passage (throttle part), 38 is the air vent hole, 50.60
is a hydraulic tappet. 51.61 is a tappet body, 52.62 is a plunger, 54 is a communication passage, 55 is a check valve, 58 is a high pressure oil chamber, and 59 is a low pressure oil chamber in the plunger.

Claims (1)

[Scope of Claims] 1. A cylinder is formed at the swinging end of a rocker arm on the intake and exhaust valve side, which is swingably supported by a rocker shaft, and a tappet body is slidably fitted into the cylinder, and the tappet a plunger slidably fitted into the body and in constant contact with the bottom of the cylinder; a low pressure oil chamber formed within the plunger; a high pressure oil chamber formed between the bottom of the tappet body and the bottom of the plunger; and the plunger. The intake/exhaust valve side rocker is formed at the bottom and includes a communication passage that allows communication between the high pressure oil chamber and the low pressure oil chamber, and a check valve provided in the communication passage, and is located upward from within the rocker shaft. A hydraulic tappet, wherein an oil passage toward a moving end is formed in the rocker arm, and oil is supplied to the low-pressure oil chamber formed in the rocker arm and the plunger located below the oil passage. A hydraulic tappet, characterized in that an air vent hole is formed at an end of the oil passage located above the low-pressure oil chamber, and the oil passage is extended downward to open above the low-pressure oil chamber. 2. In an engine with an inclined cylinder part, a cylinder formed at the intake/exhaust valve side end of the rocker arm, which has an oil passage formed therein from the rocker shaft to the intake/exhaust valve side end located below, The tappet body and the plunger are provided, and the low pressure oil chamber in the plunger is directly connected to an oil passage extending from the inside of the rocker shaft to an end on the intake and exhaust valve side located below, 2. The hydraulic tappet according to claim 1, wherein the hydraulic tappet is provided on a rocker arm whose end on the intake/exhaust valve side is located above the rocker shaft.