JPH037004B2 - - Google Patents

Abstract

PURPOSE:To prevent a syphon phenomenon by air sucked into an air vent route, when an engine stops, so as to get a certain checking function, by connecting the air vent route to the upper part of a flow-checking route which rises from an inlet of a distributor. CONSTITUTION:When an engine is started, oil is sent with pressure into a feed route 32 by the operation of an oil pump 31, and after that, the flow of the oil is divided into a lubricating oil route 34 and a distributor route 28 by an orifice 33, at the proper rate of division. Then, a part of the oil divided into the distributor route 28, flows into an air vent route 38 through an orifice 39, and is sent to a lubricating oil route 23. On the other hand, when the engine and the oil pump 31 are stopped, it is prevented that the oil in the distributor 28 is returned toward the oil pump 31-side, by a flow-checking route 30 which rises from the distributor 28. Moreover, as air in a tappet chamber 14 is sucked into a concave part 37 through the lubricating oil route 23 and the air vent route 38, according to the downward flow of the oil in the feed route 32, a syphon phenomenon in the flow-checking route 30 can be suppressed.

Description

[Detailed Description of the Invention] A. Object of the Invention (1) Industrial Field of Application The present invention relates to a system for supplying oil to a hydraulic tappet of an internal combustion engine, and in particular, to a system for supplying oil to a hydraulic tappet of an internal combustion engine, in particular, a system for supplying oil to a plurality of hydraulic tappets of a valve train. An improvement in a device comprising a distribution passage extending substantially horizontally, a backflow prevention passage rising from the inlet of the distribution passage, and a supply passage extending upward from the discharge port of an oil pump of an engine and connected to the upper end of the backflow prevention passage. Regarding.

(2) Prior art When the engine stops operating, the backflow prevention passage prevents the oil pump from operating.
This is to prevent the hydraulic oil in the distribution passage from flowing down to the oil pump side, and to enable the distribution of hydraulic oil from the distribution passage to the hydraulic tappet to be immediately resumed when the engine is restarted.

(3) Problems to be solved by the invention However, in the conventional oil supply system, when the engine is stopped, when the oil in the supply path flows down to the oil pump side, it is distributed through the backflow prevention passage due to the siphon phenomenon. It may draw out the oil from the road.

The present invention has been made in view of the above circumstances, and is capable of preventing the siphon phenomenon and reliably retaining hydraulic oil in the distribution passage when the engine is stopped, and is easy to process, connect, etc. of the oil passage. It is an object of the present invention to provide the oil supply device which is easy to maintain.

B. Structure of the Invention (1) Means for Solving the Problems In order to achieve the above object, the present invention provides a structure between a bearing pedestal provided on a cylinder head and a cam holder detachably joined to the bearing pedestal. A camshaft is rotatably supported in the cylinder head, and the cylinder head has a
A distribution passage that extends approximately horizontally and communicates with each oil supply port of a plurality of hydraulic tappets of the valve train, a backflow prevention passage that rises from the entrance of this distribution passage, and a backflow prevention passage that extends upward from the discharge port of the engine's oil pump to prevent backflow. In the oil supply device for a hydraulic tappet of an internal combustion engine, which is formed with a supply passage connected to the upper end of the stop passage, the joint surface between the bearing stand and the cam holder has the oil supply passage connected to the lubricating part of the valve train. A recess is formed to communicate between an air vent passage provided in the cam holder, the backflow prevention passage, and the supply passage, and the air vent passage is provided with an orifice for regulating the flow of oil in the passage. shall be.

(2) Effect When the engine is stopped, the air sucked into the air vent passage prevents the siphon phenomenon and provides the backflow prevention passage with a reliable backflow prevention function. Furthermore, by communicating the air vent passage with the lubricating section of the valve train, the oil flowing out from the air vent passage can be effectively used to lubricate the valve train during engine operation. The amount of oil flowing to the passage side is regulated to a minimum by the orifice.

In addition, by simply mounting the cam holder on the bearing pedestal, the backflow prevention passage, the supply passage, and the air vent passage can be easily and quickly communicated with each other at a single recess provided on one of the joint surfaces of the cam holder and the bearing pedestal. Can be done. Furthermore, if the cam holder is separated from the bearing stand, the openings and orifices of the three passages can be viewed from their joint surfaces.

(3) Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In FIG. 1, a cylinder block 1 of an internal combustion engine has a plurality of cylinders 2 arranged in the front and back directions of the paper. The cylinder head 3 fixed to the upper end of the cylinder block 1 includes:
a plurality of combustion chambers 4 corresponding to the plurality of cylinders 2;
An intake (exhaust) port 5 opening into each combustion chamber 4 is formed, and the intake (exhaust) port 5 is opened and closed by an intake (exhaust) valve 6. The valve 6 is supported by the cylinder head 3 via a valve guide 7 so as to be able to move up and down, and is driven by a valve train 8.

The valve train 8 includes a valve spring 9 that is compressed between a retainer 6a attached to the upper end of the valve 6 and the cylinder head 3 and biases the valve 6 in the closing direction, and a support hole 10 of the cylinder head 3. Hydraulic tappet 1 to be installed
1, a cam follower 12 whose base end is swingably supported by the operating end 11a of the hydraulic tappet 11 and whose distal end engages with the head of the valve 6, and a slipper surface formed on the upper side of the cam follower 12. 12a and a cam shaft 13 that engages a cam 13a.

The valve train 8 is housed in a valve train chamber 14 formed on the cylinder head 3, and the upper opening of the chamber 14 is closed by a head cover 15.

Therefore, as the camshaft 13 rotates, the cam 13a
When the tappet applies a pressing force to the slipper surface 12a of the cam follower 12 due to its lifting action, the hydraulic tappet 11 supports the base end of the cam follower 12 by supporting the base end of the cam follower 12 by applying hydraulic pressure generated in the internal hydraulic chamber.
The cam follower 12 is swung downward by a cam 13a about the working end 11a of the hydraulic tappet 11 as a fulcrum, and opens the valve 6 against the elastic force of the valve spring 9.
During this time, a small amount of hydraulic fluid leaks from the hydraulic chamber in the hydraulic tappet 11. Next, when the cam 13a releases its lifting action on the cam follower 12, the valve spring 9 pushes up the valve 6 together with the cam follower 12 to return it to the closed position. At this time, the hydraulic tappet 11 exhibits an extension function to eliminate the valve head gap. When the pressure in the hydraulic chamber inside the tappet 11 is reduced due to the extension of the hydraulic tappet 11, hydraulic oil is supplied to the hydraulic chamber from a distribution path 28, which will be described later.

In FIG. 2, the camshaft 13 is arranged horizontally along the direction in which the plurality of cylinders 2 are arranged. To support the camshaft 13, a plurality of bearing stands 16 ₁ to 16 ₃ are integrally formed on the upper surface of the cylinder head 3 and have a semicircular bearing surface 16a, and also have a semicircular bearing surface 17a. A plurality of cam holders 17 ₁ to 17 ₃ are prepared, and both bearing surfaces 1
The cam holders 17 1 to 1 are arranged such that the journal of the camshaft 13 is rotatably held between the cam holders 17 ₁ and 17 a.
7 ₃ attaches bolts 18 to bearing stands 16 ₁ to 16 ₃ , respectively.
(Fig. 4). At that time, the bearing stands 16 ₁ , 16 ₃ and the cam holders 17 ₁ , 1 at both outer positions
The joining position with 7 ₃ is defined by the positioning pin 19 and positioning collar 20 (FIG. 4) fitted therein.

As shown in FIGS. 2 and 3, the plurality of cam holders 17 ₁ to 17 ₃ are integrally connected at both ends by a pair of cross members 21, 21 each having an L-shaped cross section, and are connected to each other by a pipe-shaped cross member. A member 22 integrally connects the intermediate portions to each other. The hollow part of the pipe-shaped cross member 22 is used as a lubricating oil passage 23, and an oil supply hole 24 communicating the oil passage 23 with each bearing surface 17a of the cam holders 17 ₁ to 17 ₃ is bored in each of the cam holders 17 ₁ to 17 ₃ . The valve chamber 1 is also connected from the lubricating oil passage 23 toward the plurality of cams 13a of the camshaft 13.
An oil injection hole 25 opening at 4 is bored in the cross member 22.

Said hydraulic tappet 11 and cam follower 12
The cylinder head 3 is provided with distribution passages 28, which are arranged horizontally in the same number as the number of valves 6 used, and which extend horizontally so as to communicate with the oil supply ports 27 of each hydraulic tappet 11. A blind stopper 29 is applied.

Further, the cylinder head 3 is provided with a backflow prevention passage 30 rising from the inlet 28a of the distribution passage 28 and a supply passage 32 extending upward from the discharge port of the oil pump 31 of the engine. is provided with an orifice 33. The supply path 32 on the upstream side of this orifice 33 (that is, on the oil pump 31 side)
A lubricating oil path 34 branches from the middle and reaches a lubricating section 35 around the crankshaft of the engine.

As shown in FIGS. 2 and 5, the upper ends of the backflow prevention passage 30 and the supply passage 32 are close to each other and open on the upper surface of the bearing stand 16 ₁ at the right outer position. On the other hand, on the lower surface of the cam holder 17 ₁ that is in close contact with the upper surface of the bearing stand 16 ₁ , there is a recess 37 that communicates between the upper ends of both passages 30 and 32, and an air vent passage 38 that communicates this recess 37 with the lubricating oil passage 23. An orifice 39 is provided in the air vent passage 38.

The recess 37 is formed at the same time as the cam holder ₁₇₁ is cast.

Note that the recess 37 may be formed on the upper surface of the bearing stand 16 ₁ .

Referring again to FIG. 2, the bearing stand 16 in the left outer position
₃ and the cam holder 17 ₁ are provided with defoaming passages 40 , 40 rising from the depths of the distribution passage 28 and communicating with the lubricating oil passage 23 .
One orifice 42 of 0 is provided.

The bearing stand 16 ₃ and the cam holder 17 ₁ are also provided with a relief passage 43 that connects the distribution passage 28 and the lubricating oil passage 23 together with the oil supply hole 24. A relief valve 45 is provided which opens when the pressure increases above the above level.

Next, the operation of this embodiment will be explained. When the engine is started, oil is pumped from its discharge port to the supply path 32 by the operation of the oil pump 31 at an appropriate ratio through the orifice 33. The oil sent to the lubricating oil passage 34 is supplied to the lubricating section 35 around the crankshaft.

On the other hand, oil sent from the supply path 32 to the distribution path 28 passes through a recess 37 and a backflow prevention path 30 on the way, but at this time, a portion of the oil flows out into the air vent path 38 while the flow rate is regulated by an orifice 39. Then, it moves to the lubricating oil path 23.

The oil sent to the distribution path 28 is supplied to each oil supply port 27 of the plurality of hydraulic tappets 11, 11, . . . as hydraulic oil.

Further, a part of the oil sent to the distribution passage 28 flows out to the defoaming passages 40 and 41 while the flow rate is regulated by the orifice 42 together with the bubbles contained therein.
This also moves to the lubricating oil path 23.

Further, when the pressure in the distribution passage 28 exceeds a specified value, the relief valve 45 opens and the relief passage 43 is made conductive, so that a part of the oil in the distribution passage 28 flows into the relief passage 43 and the lubricating oil passage. Move on to 23. When the pressure in the distribution path 28 drops to a specified value, the relief valve 45 closes. Such relief valve 4
5 opens and closes each hydraulic tappet 1 in the distribution passage 28.
The optimal oil pressure for refueling 1 is maintained.

A portion of the oil transferred from the air vent passage 38, degassing passages 40, 41, and relief passage 43 to the lubricating oil passage 23 passes through the oil supply holes 24, 24 and lubricates the journal of the camshaft 13, and the remaining oil is transferred to the lubricating oil passage 23. oil injection hole 2
5, 25... onto the plurality of cams 13a, 13a, and lubricates the sliding surfaces between the pair of cams 13a and cam followers 12. In this way, the valve train 8 is lubricated.

Oil leaking from each hydraulic tappet 11 and oil that has finished lubricating the valve train 8 flow down from the valve train chamber 14 through a return oil path (not shown), return to the oil pan at the bottom of the engine, and are discharged from the oil pump 31 again. Ru.

Next, when engine operation is stopped, oil pump 3
1 also stops at the same time, the oil in the recess 37 and the supply path 32 flows down to the oil pump 31 side, that is, flows backwards, but the oil in the distribution path 28 rises above the distribution path 28 to the backflow prevention path 30. This prevents the backflow to the oil pump 31 side. Moreover, as the oil in the supply passage 32 flows down, the air in the valve train chamber 14 is sucked into the recess 37 via the lubricating oil passage 23 and the air vent passage 38, so the siphon phenomenon in the backflow prevention passage 30 is suppressed. Backflow of oil within the distribution path 28 can be prevented.

In this way, the hydraulic oil is retained in the distribution passage 28 even after the engine has stopped, so when the engine is restarted, the oil is supplied from the distribution passage 28 to each hydraulic tappet 11 without having to supply oil from the oil pump 31. is carried out promptly, and a delay in the operation of the hydraulic tappet 11 can be prevented.

C. Effects of the Invention As described above, according to the present invention, the camshaft is rotatably supported between the bearing stand provided on the cylinder head and the cam holder detachably joined to the bearing stand,
A distribution passage that communicates with each oil supply port of a plurality of hydraulic tappets of the valve train and extends approximately horizontally, a backflow prevention passage that rises from the entrance of this distribution passage, and a backflow prevention passage that extends upward from the discharge port of the oil pump. In a cylinder head in which a supply passage connected to an upper end is formed in the cylinder head, an air vent passage provided in the cam holder to communicate with the lubricating part of the valve gear, and an air vent passage provided in the cam holder to communicate with the lubricating part of the valve operating device are provided at the joint surface of the bearing stand and the cam holder. A recess is formed to communicate between the stop passage and the supply passage, and the air vent passage is provided with an orifice that regulates the flow of oil in the passage, so that when the engine is stopped, the air sucked into the air vent passage is This makes it possible to prevent the siphon phenomenon and provide the backflow prevention passage with a reliable backflow prevention function, thereby ensuring that the hydraulic oil to be supplied to the hydraulic tappet is retained in the distribution passage. Moreover, by communicating the air vent passage with the lubricating section of the valve train, the oil flowing out from the air vent passage can be effectively used to lubricate the valve train during engine operation, so that the oil pump Since operating loss can be reduced and the amount of oil flowing into the air vent passage is regulated to a minimum by the orifice, the necessary amount of pressure oil is always supplied to each hydraulic tappet through the distribution passage. can be reliably supplied.

In addition, by simply mounting the cam holder on the bearing pedestal, the backflow prevention passage, the supply passage, and the air vent passage can be made to communicate with each other at a single recess provided in the joint surface between the cam holder and the bearing pedestal. In addition, the connection, handling, processing, etc. of these passages are facilitated, and the device is also easy to assemble, contributing to cost reduction. Furthermore, if the cam holder is separated from the bearing stand, the openings and orifices of the three passages can be viewed from their joint surfaces, so maintenance work such as inspection and cleaning can be easily performed.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a longitudinal sectional view of the main parts of an internal combustion engine equipped with the device of the invention, FIG. 2 is a longitudinal sectional front view of the main parts of the engine, and FIG. 3 is a longitudinal sectional view of the main parts of the engine. 4 is a bottom view of the cam holder assembly of the same engine, and FIGS. 4 and 5 are sectional views taken along lines - and - in FIG. 3. 8... Valve gear, 11... Hydraulic tappet, 23
... Lubricating oil path, 27 ... Hydraulic tappet oil filler port,
28... Distribution path, 28a... Inlet, 30... Backflow prevention path, 31... Oil pump, 32... Supply path, 38... Air vent path.

Claims (1)

[Claims] 1 a bearing stand 16 ₁ provided in the cylinder head 3;
The camshaft 13 is rotatably supported between the cam holder 17 ₁ and the cam holder 17 ₁ which is removably connected to the bearing stand 16 1 . A distribution passage 28 that communicates with the port 27 and extends approximately horizontally, and this distribution passage 28
A system for supplying oil to a hydraulic tappet of an internal combustion engine, comprising a check passage 30 rising from the inlet of the engine, and a supply passage 32 extending upward from the discharge port of an oil pump 31 of the engine and connected to the upper end of the check passage 30. In the device, the bearing stand 16 ₁ and the cam holder 1
7 ₁ , an air vent passage 38 provided in the cam holder 17 ₁ to communicate with the lubricating part of the valve operating device 8, and the backflow prevention passage 30.
and a recess 37 that communicates the three parts of the supply path 32 with each other.
A system for supplying oil to a hydraulic tappet of an internal combustion engine, characterized in that the air vent passage 38 is provided with an orifice 39 for regulating the flow of oil in the air vent passage 38.