JPS6245912A - Oil feeding device for hydraulic tappet of internal combustion engine - 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 A0 Object of the Invention (11 Industrial Field of Application) The present invention relates to a system for supplying oil to hydraulic tappets of an internal combustion engine, and more particularly, to a system for supplying oil to hydraulic tappets of an internal combustion engine, and more particularly, to a system for supplying oil to hydraulic tappets of an internal combustion engine. This invention relates to 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. .

(2) Prior art The above-mentioned backflow prevention passage prevents the hydraulic oil in the distribution passage from flowing down to the oil pump side when the engine operation is stopped and the oil pump stops operating accordingly. This is to enable the distribution of hydraulic fluid from the distribution path to the hydraulic tappet to be immediately resumed when the system 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 provides an oil supply device for the hydraulic tappet, which prevents the siphon phenomenon when the engine is stopped and can reliably retain hydraulic oil in the distribution path. The purpose is to

B0 Structure of the Invention (1) Means for Solving the Problems In order to achieve the above object, the present invention connects an air vent passage communicating with the lubricating part of the valve train to the second part of the check passage. It is characterized by what it did.

(2) Effect When the engine is stopped, as the oil in the supply path flows down to the oil pump side, the air vent I'lff1 path (J
j Air is sucked into the supply path, which suppresses the siphon phenomenon in the backflow prevention path. Therefore, the backflow prevention passage can reliably prevent backflow of oil in the distribution passage.

While the engine is operating, a portion of the oil passing through the supply passage flows into the air vent passage, but this oil is efficiently used to lubricate the valve gear.

(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. A cylinder head 3 fixed to the upper end of the cylinder block 1 has a plurality of combustion chambers 4 corresponding to the plurality of cylinders 2, and an intake (exhaust) boat 5 opening into each combustion chamber 4.
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 retainer 6a provided at the upper end of the valve 6.
and the cylinder head 3, the valve spring 9 compresses the valve 6 in the closing direction, and the support hole 10 of the cylinder head 3.
Hydraulic tappet 11 attached to this hydraulic tappet 1
1], a cam follower 12 whose base end is swingably supported by a and whose distal end engages with the head of the valve 6, and a cam on a slipper surface 12a formed on the upper side of the cam follower 12. The camshaft 13 engages the camshaft 13a.

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

As the camshaft 13 rotates, when the cam 13a applies a pressing force to the slipper surface 12a of the cam follower 12 due to its lifting action, the hydraulic tappet 11 is pressed down by the hydraulic pressure generated in the internal hydraulic chamber. As a result of supporting the base end of the cam follower 12, the cam follower 12 is swung downward by the cam 13a using the operating end 1'la 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, hydraulic oil slightly leaks from the hydraulic chamber within 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 hydraulic 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 22, 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. In order to support the camshaft 13, a plurality of bearing stands 161 to 163 having a semicircular bearing surface 16a are integrally formed on the upper surface of the cylinder head 3, and a bearing surface 17a also having a semicircular shape.
A plurality of cam holders 171 to 173 are prepared,
The cam holder 17° to 17
3 is the bolt 18 (fourth
(Fig.) is fixed. At that time, the bearing stand 1 at both outer positions
6. ．． The joining position between cam holder 163 and cam holder 171, 173 is defined by positioning pin 19 and positioning collar 20 (FIG. 4) fitted therein.

As shown in FIGS. 2 and 3, a plurality of campolders 17
I~173 are a pair of cross members 21 having a cross-sectional shape
, 21, and the intermediate portions are integrally connected to each other by a pipe-shaped cross member 22. The hollow part of the pipe-shaped cross member 22 is used as a lubricating oil passage 23, and the core oil passage 23 is connected to the cam holder 17. ~17
The oil supply hole 24 communicating with each cam holder 17. ~173, and the lubricating oil passage 23
from the valve chamber 14 toward the plurality of cams 13a of the camshaft 13.
An oil injection hole 25 opening to the cross member 22 is formed in the cross member 22.

The hydraulic tappets 11 and cam followers 12 are arranged horizontally in the same number as the number of valves 6 used, and a horizontally extending distribution passage 28 is bored in the cylinder head 3 so as to communicate with the oil supply port 27 of each hydraulic tappet 11. established,
A blind plug 29 is placed in the perforation.

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

As shown in FIGS. 1 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 161 at the right outer position. On the other hand, the bearing stand 161
The lower surface of the cam holder 171 that is in close contact with the upper surface includes a recess 37 that communicates between the upper ends of both passages 30 and 32, and a recess 37 that communicates between the upper ends of both passages 30 and 32.
7 and an air vent passage 38 communicating with the lubricating oil passage 23, and the air vent passage 38 is provided with an orifice 39.

The recess 37 is formed at the same time as the cam holder 17I is cast.

Note that the recess 37 is located at the bearing stand 16. It may be formed on two sides.

Referring again to FIG. 2, the bearing stand 16 and the cam holder 17. , a defoaming passage 40, 40 is formed extending from the back of the distribution passage 28 and communicating with the lubricating oil passage 23, and an orifice 4 is provided in one of these passages 40, 40.
2 is provided.

The bearing stand 163 and the cam holder 171 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 that opens when the pressure increases.

Next, the operation of this embodiment will be explained. When the engine is started, the oil pump 31 is operated and the oil is pumped from its discharge port to the supply path 32 through the orifice 33 at an appropriate ratio. and the distribution path 28,
The oil sent to the lubricating oil path 34 is supplied to the lubricating section 3 around the crankshaft.
5.

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 channel 28 is supplied to a plurality of hydraulic tappets 11.1.
1... is supplied to each oil supply port 27 as the hydraulic oil.

Further, a part of the oil sent to the distribution passage 2 flows out into the defoaming passage 40.41, with the flow rate being regulated by the orifice 42, together with the bubbles contained therein, and also moves to the lubricating oil passage 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. By opening and closing the relief valve 45 in this manner, the optimal oil pressure for supplying oil to each hydraulic tappet 11 is maintained in the distribution passage 28.

A portion of the oil transferred from the air vent passage 38, degassing passage 40, 41, and relief passage 43 to the lubricating oil passage 23 is transferred to the oil supply hole 2.
4.24 to lubricate the journal of the camshaft 13,
The remaining oil falls onto the plurality of cams 13a, 13a from the plurality of oil injection holes 25, 25, 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 lubricating the valve train 8 flow down the return oil passage (not shown) from the valve train chamber 14, return to the oil pan at the bottom of the engine, and are discharged from the oil pump 31 again. Ru.

Next, when the operation of the engine is stopped, the operation of the oil pump 31 is also stopped at the same time, so the oil in the recess 37 and the supply path 32 flows down to the oil pump 31 side, that is, flows backward, but the oil in the distribution path 28 The reverse flow toward the oil pump 31 is prevented by the reverse flow passage 30 rising above the distribution passage 28. Moreover, as the oil in the supply path 32 flows down, the valve train chamber 1
Since the air of No. 4 is sucked into the fourth section 37 through the lubricating oil passage 23 and the air vent passage 38, the siphon phenomenon in the backflow prevention passage 30 is suppressed, and the backflow of oil in the distribution passage 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, oil can be supplied from the distribution passage 28 to each hydraulic tappet 11 without waiting for oil to be supplied from the oil pump 31. is carried out promptly, and the hydraulic tappet 1
1. The delay in operation can be prevented.

C8 Effects of the Invention According to the present invention, the air vent passage is connected to the upper part of the backflow prevention passage rising from the entrance of the distribution passage, so that when the engine is stopped, the air sucked into the air vent I passage is Accordingly, the siphon phenomenon can be prevented and a reliable backflow prevention function can be provided to the backflow prevention passage, so that the hydraulic oil to be supplied to the hydraulic tappet can be reliably retained in the distribution passage.

Furthermore, since the air vent passage communicates 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 while the engine is running, and therefore the oil pump operating losses are significantly reduced.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a longitudinal cross-sectional view of a main part of an internal combustion engine equipped with a device of the present invention. Figure 2 is a vertical sectional front view of the main parts of the engine, Figure 3 is a bottom view of the cam bolter S1 solid of the engine, Figures 4 and 5 are the IV-IV line and V-V line of Figure 3. FIG. 8...Valve train, 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 passage patent filed by Honda Motor Co., Ltd. Figure 2 Figure 1

Claims (1)

[Claims] A distribution passage that communicates with each oil supply port of a plurality of hydraulic tappets of a valve train and extends approximately horizontally, a check passage that rises from the entrance of this distribution passage, and a passage that extends upward from a discharge port of an oil pump of an engine. A system for supplying oil to a hydraulic tappet of an internal combustion engine, comprising a supply passage connected to an upper end of a check passage, characterized in that an air vent passage communicating with a lubricating part of a valve train is connected to the top of the check passage. A system for supplying oil to the hydraulic tappet of an internal combustion engine.