JPS622254Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a breathing hole structure of a valve bridge.

(Prior art and its problems) The breathing hole of the conventional valve bridge was developed in 1974.
As shown in 93636, the two fumarole holes (breathing holes) are formed in a V shape, both of which open upward at their upper ends and have a recessed portion at the upper end for receiving oil. . Therefore, both jet holes serve as inflow and discharge holes for lubricating oil, and while oil accumulates in the upper oil receiving recess and attempts to flow into the internal space, the same jet As the oil tries to squirt out inside the hole, the flow of lubricating oil becomes poor. As a result, a large amount of lubricating oil accumulates in the internal space, reducing the scavenging performance of the internal space, resulting in poor breathing efficiency and affecting valve operation.

(Purpose of the invention) The purpose of the invention is to improve the scavenging performance and breathing efficiency by allowing lubricating oil to smoothly flow between the internal space and the outside of the valve bridge.

Another object of the present invention is to prevent oil leakage from inside the valve arm case and to facilitate machining of the breathing hole.

(Means for Achieving the Object) In order to achieve the above object, the present invention provides a valve arm chamber 8 covered by the valve arm case 2, which is located at a distance from the fuel injection valve 41 in the center of the valve arm chamber. A vertical fixed shaft 21 is provided, and is fitted onto the outer circumferential side of the fixed shaft 21 so as to be movable up and down.
Alternatively, in the valve bridge that communicates with the exhaust valve, an internal space S whose lower side is closed by the fixed shaft 21 and whose volume changes as the valve bridge moves up and down is formed in the valve bridge, and the internal space S and the valve arm chamber 8 are connected to each other. A generally horizontal breathing hole 3 that communicates with the inside
5 is formed in the valve bridge wall portion, the breathing hole 35 is opened toward the central part of the valve arm chamber where the injection valve 41 is located, and the valve bridge wall is close to the side wall of the valve arm case on the opposite side from the breathing hole 35. In part,
A substantially L-shaped lubricating oil supply hole 36 extending from the upper end surface of the valve bridge to the internal space S of the valve bridge is formed to guide the lubricating oil accumulated on the upper end surface of the valve bridge to the internal space S, and the horizontal portion of the lower end of the supply hole 36 is formed as a breathing hole. 35 and is formed approximately on the same straight line.

(Function) During engine operation, lubricating oil flows into the valve bridge internal space S from the vertical lubricating oil supply hole 36 with an opening at the top, and most of the lubricating oil discharged from the valve bridge internal space S flows through the horizontal breathing hole. 35, lubricating oil flows smoothly and breathing efficiency is improved.

In addition, since the horizontal breathing hole 35 faces the center of the valve arm case 2, lubricating oil can be transferred to the valve arm case 2.
There is no need to worry about lubricant leaking as it cannot be sprayed directly onto the side walls of the lubricant.

(Example) Longitudinal section of the upper end portion of the internal combustion engine (abbreviated in Figure 2)
In FIG. 1 showing the cross section), the cylinder head 1
A valve arm case 2 is fixed to the upper end surface, and a case cover 3 is attached to a gasket 4 on the upper side of the valve arm case 2.
is located through. This case cover 3 is detachably attached to the valve arm case 2 with a fastening fitting 6. That is, a female thread is formed at the upper end of the bolt 7 for fixing the spindle holder 5 to the cylinder head 1, and a male thread at the lower end of the tightening fitting 6 inserted from the upper side of the case cover 3 into the valve arm chamber 8. The case cover 3 is tightened from above by screwing it onto the upper end of the bolt 7.

An intake valve arm 10 is rotatably supported on a support shaft 9 fixed to the support shaft holder 5. A tappet 11 is in contact with one end of the intake valve arm 10, and a concave bearing 12 and a ball 13 are connected to the other end. A presser metal fitting 16 of the valve bridge 15 is in contact with the valve bridge 15 via the valve bridge 15.

The valve bridge 15 is formed with a downwardly opening guide hole 20 whose upper end is closed by the presser fitting 16, and the valve bridge 15 is fitted onto a vertical fixed shaft 21 fixed to the cylinder head 1 so as to be movable up and down. There is. Both arms 1 of valve bridge 15
5a and 15b are in contact with the upper ends of the pair of intake valves 22, respectively. Arm portion 15b on the side far from the support shaft 9
A valve clearance adjustment screw 23 is screwed into the intake valve 22 on the side farther from the support shaft 9.
It is in contact with the arm portion 15b via. Intake valve 22
A spring catch 25 is fixed to the upper end of the
Valve springs 27 and 28 are compressed between the spring seat 25 and the upper surface of the cylinder head 1 and between the spring seat 25 and the flange portion of the valve guide 26, respectively.
The elastic forces of 7 and 28 push the intake valve 22 and valve bridge 15 upward.

A lubricating oil passage 30 is formed in the intake valve arm 10 from the fitting part with the support shaft 9 to an oil passage 29 in the concave bearing 12. There is an opening in the mating part. That is, the lubricating oil sent from the lubricating oil pump to the fitting part between the support shaft 9 and the intake valve arm 10 through an appropriate oil path is as follows.
The oil is sent through the oil passages 30 and 29 to the fitting portion between the ball 13 and the bearing 12, and falls onto the presser fitting 16.

The valve bridge 15 has a lubricating oil passage 3 extending from a portion adjacent to the holding fitting 16 to a portion in contact with the intake valve 22.
2 is formed, and a breathing hole 35 that communicates the internal space S of the valve bridge 15 with the valve arm chamber 8, and a lubricating oil that flows from the upper end of the valve bridge 15 near the holding fitting 16 to the internal space S as shown in FIG. A supply hole 36 is formed. In other words, - in Figure 1
In FIG. 3, which is an enlarged cross-sectional view, the breathing hole 3
5 is formed to be perpendicular to the center line O of the valve bridge 15, while the supply hole 36 is formed in an "L" shape at a portion symmetrical to the breathing hole 35 with respect to the center line O, and the lower end of the supply hole 36 The horizontal portion is formed on the same straight line as the breathing hole 35. Breathing hole 35
When machining the supply hole 36, the lower horizontal part of the oil supply hole 36 is machined in the process of drilling the breathing hole 35 by inserting a drill from the right side in FIG. Perform perforation processing.

The lubricating oil that has fallen from the above-mentioned concave bearing 12, etc.
It enters the internal space S through the oil supply hole 36 and lubricates the fitting portion between the valve bridge 15 and the fixed shaft 21. A part of the lubricating oil accumulated in the internal space S is blown out into the valve arm chamber 8 through the breathing hole 35 when the volume of the internal space S is reduced when the valve bridge 15 is lowered. The general function of the breathing hole 35 is as follows:
The purpose is to keep constant the pressure in the internal space S whose volume changes due to the vertical movement of the valve bridge 15, and to smoothly move the valve bridge 15 up and down. That is, when the valve bridge 15 descends and the internal space S contracts, the air in the internal space S is discharged into the valve arm chamber 8 through the breathing hole 35, and when the valve bridge 15 rises and the internal space S expands, the air in the internal space S is discharged through the breathing hole 35. There are 35 breathing holes in
Air is sucked into the internal space S from the valve arm chamber 8 through the valve arm chamber 8.

FIG. 2 is a top view of FIG. 1 shown with the case cover 3 removed, and in this FIG. A substantially parallel exhaust valve arm 40 is supported on the support shaft 9, and the portion of the exhaust valve arm 40 on the side opposite to the control side (left side in FIG. 2) is slightly longer than the intake valve arm 10. The valve bridge 15' that abuts the exhaust valve arm 40 has exactly the same structure as the valve bridge 15 that abuts the intake valve arm 10, but both valve bridges 15, 15' have breathing holes 35, 35' that are connected to the valve, respectively. It is arranged so as to face the central portion of the arm chamber 8, for example, toward the fuel injection valve 41 side. That is, the valve bridge 1 on the exhaust side
5' is arranged in a state rotated by 180 degrees around the valve bridge center line O' from the same state as the valve bridge 15 on the intake side. Moreover, the valve bridge 15' on the exhaust side is arranged so that its valve clearance adjustment screw 23' is on the internal combustion engine control side (the left side in FIG. It is placed to the right of the In addition, the position of the valve clearance adjustment screw 23' is shifted from the position directly below the exhaust valve arm 40 so that the exhaust valve arm 40 does not get in the way when turning the valve clearance adjustment screw 23' of the valve bridge 15' on the exhaust side. There is. That is, the arm portion 1 of the exhaust side valve bridge 15'
The length direction of 5'a, 15'b is inclined with respect to the length direction of the exhaust valve arm 40 in the paper plane of FIG.
The length direction of the intake valve arm 10 is also inclined at the same angle as the exhaust side.

The intake and exhaust valve arms 10 and 40 operate to open the breathing hole 3.
If lubricating oil is spouted from 5, 35',
The fuel is injected toward the fuel injection pump 41 at the center of the valve arm chamber 8 . That is, at the intake side valve bridge 15, the air is ejected only toward the side opposite to the valve arm case portion A closest to the intake side valve bridge 15, and at the exhaust side valve bridge 15', the air is emitted opposite to the valve arm case portion B closest to the exhaust side valve bridge 15'. Spray only towards the side. Therefore, the lubricating oil is not directly sprayed onto the valve arm case 2, and no lubricating oil leaks from between the valve arm case 2 and the case cover 3. In addition, in the embodiment shown in FIG. 2, the control side (left side in FIG. 2) is closer to the intake side valve bridge 15.
Exhaust side valve bridge 15' located far from
Since the valve clearance adjusting screw 23' is arranged so as to be on the operating side, it becomes easy to reach out from the operating side and turn the valve clearance adjusting screw 23'.

(Effects of the invention) As explained above, according to the invention: (1) The breathing hole 35 is formed generally horizontally, one lubricating oil supply hole 36 is formed in an L-shape, and the upper end of the upwardly opening shape is formed. Since the lubricating oil is configured to flow in from the inner space S, the breathing hole 35 functions exclusively for draining the oil in the internal space S, and the supply hole 36 mainly performs the oil inflow function rather than the oil discharge function.

In other words, oil is inhaled and discharged through the supply hole 36 and the breathing hole 3.
Since the space is divided into 5 parts, the breathing tempo becomes faster and breathing efficiency improves, and a large amount of lubricating oil does not accumulate in the internal space S, improving the scavenging performance.

(2) Internal space S of valve bridge 15 and valve arm chamber 8
A generally horizontal breathing hole 35 communicating with the inside is formed in the valve bridge wall portion, and the breathing hole 35 is
An L is opened toward the center of the valve arm chamber where the injection valve 41 is located, and the lubricating oil supply hole 36 on the side opposite to the injection valve 41 in the center of the valve arm chamber is opened upward at the upper end surface of the valve bridge. Since the valve bridge is formed in a shape of
It is discharged only to the central part of the valve arm chamber through the valve arm chamber.

Therefore, the lubricating oil spouted from the breathing hole 35 is not sprayed directly onto the side wall of the valve arm case 2, and oil leakage from the valve arm chamber 8 can be reliably prevented, and the inner circumferential wall of the valve arm case 2 will become dirty. Not at all.

(3) Since the lubricating oil supply hole 36 is formed in a substantially L-shape, there is no need to drill the hole diagonally with respect to the center line of the valve bridge 15, making the machining operation easier.

(4) Horizontal breathing hole 35 and L-shaped lubricating oil supply hole 36
Since the lower horizontal portions of the holes are arranged approximately on the same straight line, both holes can be drilled at the same time, making the processing easier.

(5) Since the valve bridge 15 on the intake side and the valve bridge 15' on the exhaust side only have a phase difference of 180 degrees, they can be of the same structure, and the labor of manufacturing parts can be greatly reduced. can.

[Brief explanation of the drawing]

Figure 1 is a vertical cross-sectional view (-cross-sectional view in Figure 2) of the valve arm case portion of an internal combustion engine to which the present invention is applied, and Figure 2 is the first valve arm case shown with the case cover removed.
FIG. 3 is a top view in the direction of arrows in the figure, and FIG. 3 is a partial enlarged view of the - cross section of FIG. 8...Valve arm chamber, 10...Intake valve arm, 15,1
5'... Valve bridge, 21... Fixed shaft, 22
...Intake valve, 35, 35'...Breathing hole, 36...
Lubricating oil supply hole, S...Internal space.

Claims (1)

[Scope of utility model registration request] A vertical fixed shaft 21 is provided in the valve arm chamber 8 covered by the valve arm case 2 at a distance from the fuel injection valve 41 in the center of the valve arm chamber, and is movable up and down on the outer circumferential side of the fixed shaft 21. In the valve bridge that transmits the operation of the fitted valve arms 10, 40 to the intake valve 22 or the exhaust valve, there is an interior in the valve bridge whose lower side is closed off by the fixed shaft 21 and whose volume changes as the valve bridge moves up and down. A generally horizontal breathing hole 35 that forms a space S and communicates between the internal space S and the inside of the valve arm chamber 8 is formed in the valve bridge wall portion, and the breathing hole 35 is connected to the central part of the valve arm chamber where the injection valve 41 is located. Opening toward the side, the above-mentioned breathing hole 3
A substantially L-shaped lubricating oil supply hole 36 extending from the upper end surface of the valve bridge to the internal space S of the valve bridge is formed in the valve bridge wall portion near the side wall of the valve arm case on the opposite side from 5, so that the lubricating oil accumulated on the upper end surface of the valve bridge is drained internally. A breathing hole structure of a valve bridge characterized in that the lower horizontal portion of the supply hole 36 is formed on the same straight line as the breathing hole 35 so as to lead to the space S.