JPH0518215A - Ship shaped rocker arm type valve system of overhead valve engine - Google Patents

Abstract

PURPOSE:To simplify absorptive structure of a valve clearance so as to reduce noise of a valve system at a low cost. CONSTITUTION:A so-called valve lash adjuster constructed by so-called a lubricating oil reservoir chamber 14, a check valve chamber 12, an elastically pressed spring 8, and the like, is incorporated between the rocker arm retaining member 4 and the stud member 3 of a rocker arm 6. It is thus possible to simplify absorptive structure of a valve clearance so as to manufacture a valve system at a low cost, since the already existent members such as the rocker arm retaining member 4, the stud member 3, and the like, especially the fitting clearance 18 of both members 3, 4, can be utilized effectively as a lublicating oil leaking passage 16, while the function of the rocker arm retaining member 4 can be also utilized as that of a plunger.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a boat-type rocker arm type valve operating device for an overhead valve engine, and provides a valve operating device that simplifies the structure for absorbing valve clearance and reduces the noise of the valve operating device at low cost.

[0002]

2. Description of the Related Art Recently, in order to reduce the production cost of an engine, it is not uncommon for the rocker arm to be manufactured at low cost by forming it into a boat shape made of a sheet metal press. The present invention is directed to a valve operating system for an overhead valve engine incorporating the boat-shaped rocker arm, and its basic structure is, as shown in FIG. 1 or 8, a stud member 3 in a rocker arm chamber 2 of an overhead valve engine E. , And the rocker arm pressing member 4 approaches and separates from the cylinder head 1 on the stud member 3 in the vertical direction P.
The rocker arm holding member 4 is formed with a partially spherical receiving surface 5, and the rocker arm 6 is machined into a boat shape with a U-shaped cross section by using a metal plate, and the boat-shaped rocker arm 6 is partially spherical. The pressing surface 7 is provided as a recess, and the pressing surface 7 is brought into surface contact with the receiving surface 5 of the rocker arm pressing member 4 from the lower side facing the cylinder head 1 so that the boat-shaped rocker arm 6 can swing on the rocker arm pressing member 4. It is a supported form.

As a conventional valve operating system in which the boat-shaped rocker arm is assembled, as shown in FIG. 8, a push rod 24 for swinging the boat-shaped rocker arm 6 of the vertical overhead valve engine E is provided via a tappet (not shown). The valve lash adjuster is incorporated into the tappet to absorb the valve clearance and reduce the noise of the valve operating device.

[0004]

However, the valve lash adjuster described above includes a tubular tappet body,
Since the plunger is fitted into the tappet body, and the plunger spring and the check ball are interposed between these members, the structure becomes complicated and the production cost becomes high. An object of the present invention is to eliminate the valve clearance simply and inexpensively.

[0005]

Means for achieving the above object will be described below with reference to the drawings illustrating an embodiment. That is, the present invention 1 is the boat type rocker arm type valve operating device for an overhead valve engine of the basic structure, wherein the stud member 3 is used.
The rocker arm pressing member 4 is supported by the elastic spring 8 and the elastic spring 8 elastically presses the rocker arm pressing member 4 downwardly B toward the cylinder head 1 toward the stud member 3 to introduce lubricating oil into the stud member 3. The passage 10 and the check valve chamber 12 are provided, and the outlet 11 of the lubricating oil introduction passage 10 is connected to the check valve chamber 1
2, the stud member 3 and the rocker arm pressing member 4
The lubricating oil storage chamber 14 is provided at the boundary portion 13 with the side of the, the lubricating oil storage chamber 14 is communicated with the check valve chamber 12, and the lubricating oil from the lubricating oil introduction passage 10 is passed through the check valve chamber 12. The rocker arm pressing member 4 and the stud member are configured such that the lubricating oil from the lubricating oil storage chamber 14 is guided to the lubricating oil storage chamber 14 and the valve body 17 of the check valve chamber 12 cannot reversely flow the lubricating oil from the lubricating oil storage chamber 14. When the rocker arm 6 receives a force of upward A that separates from the cylinder head 1, a rocker arm pressing member is formed with a fitting insertion gap 18 between the rocker arm 6 and the third side as a lubricant oil leak passage 16 from the lubricant oil storage chamber 14 to the rocker arm chamber 2. 4 moves upward with respect to the stud member 3, the lubricating oil storage chamber 14 is compressed, and the check valve body 17 of the check valve chamber 12 moves to the lubricating oil introducing passage 10.
The outlet 11 is closed, the lubricating oil is leaked from the lubricating oil storage chamber 14 to the rocker arm chamber 2 through the lubricating oil leak passage 16, and the rocker arm 6 is moved upward along the stud member 3.
It is characterized in that it can be moved to. The lubricating oil introduction passage 10 includes both a lubricating oil discharge passage led from the forced lubrication device of the engine E or a passage for receiving and guiding the spray mist of the lubricating oil filling the rocker arm chamber 2.

[0006]

(1) At a low temperature such as when the engine E is started, the rocker arm pressing member 4 is pressed downward B along the stud member 3 by the elastic force of the elastic spring 8, and the rocker arm pressing member 4 comes into contact with the rocker arm pressing member 4 from below. Similarly, 6 is pressed downward B to contact the intake / exhaust valve and absorb the valve clearance. In this case, the lubricating oil storage chamber 14 expands, so that the lubricating oil from the lubricating oil introducing passage 10 will be discharged from the check valve chamber 12
Through the oil into the lubricating oil storage chamber 14.

(2) When the temperature of the engine E rises and the intake / exhaust valve and the push rod thermally expand, the rocker arm 6 receives a force of upward A, and the rocker arm pressing member 4 moves upward A with respect to the stud member 3. Push. Therefore, the lubricating oil storage chamber 14 is compressed, the check valve body 17 of the check valve chamber 12 closes the outlet 11 of the lubricating oil introduction passage 10, and the lubricating oil of the lubricating oil storage chamber 14 is discharged from the lubricating oil leakage passage 16. Since it leaks into the rocker arm chamber 2, the rocker arm 6 escapes upward A along the stud member 3. Therefore, the rocker arm 6 swings while absorbing the valve clearance, so that the intake / exhaust valve does not open except during the intake / exhaust stroke. The engine E
When the intake / exhaust valve contracts and the rocker arm 6 descends, the lubricating oil flows from the lubricating oil introduction passage 10 into the storage chamber 14 as described in (1) above. Can be compensated.

[0008]

EFFECTS OF THE INVENTION Between the rocker arm pressing member and the stud member of the rocker arm, an adjusting mechanism including a lubricating oil storage chamber, a check valve chamber, an elastic spring, etc. is incorporated, so to speak, a valve.
Since it is a lash adjuster, it is possible to use existing members such as rocker arm pressing members and stud members.
(In particular, to effectively use the fitting gap of both members)
Since the rocker arm pressing member also has the function of the plunger, the structure for absorbing the valve clearance can be simplified and the manufacturing cost can be reduced as compared with the adjuster incorporated in the tappet as in the above-mentioned conventional technique.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a longitudinal sectional view of a main part of a valve train in a rocker arm chamber of a vertical overhead valve engine showing a first embodiment, and a rocker arm covered with a rocker arm cover above a cylinder head 1 of a vertical overhead valve engine E. The chamber 2 is formed.

A headless stud bolt 3a is fastened to the cylinder head 1 with a fastening nut 19, and a cylindrical rocker arm pressing member 4 is inserted and supported in the upright stud bolt 3a so as to move forward and backward in the vertical direction P. A partially spherical receiving surface 5 is formed on the lower portion of the pressing member 4. The rocker arm 6 is manufactured into a boat shape by sheet metal stamping, the front and rear cross-section of the rocker arm 6 is formed in a U shape with an upward opening, and a partially spherical pressing surface 7 is provided in the middle of the rocker arm 6 on the left and right sides. The insertion opening 21 is opened in the pressing surface 7. The rocker arm 6 is inserted into the stud bolt 3a, the pressing surface 7 of the rocker arm 6 is brought into surface contact with the receiving surface 5 of the rocker arm pressing member 4 from below, and the stud cap 22 is relatively slidably covered on the rocker arm pressing member 4. Then, the pressing member 4 is fixed by the lock nut 23 so that the pressing member 4 cannot be removed from the stud bolt 3a. The input portion 6a of the boat-shaped rocker arm 6 swingably supported by the stud bolt 3a is brought into contact with the push rod 24 from above, and the push rod 24 is passed through the tappet to drive the engine E.
The output portion 6b of the rocker arm 6 is brought into contact with the stem end of the opening / closing valve 25 from above while being linked to the valve operating cam shaft. The open / close valve 25 means both an intake valve and an exhaust valve.

A lubricating oil receiving recess 26 is formed in the upper part of the lock nut 23 so as to face the rocker arm chamber 2, and the check valve chamber 12 is provided in the head 27 of the stud bolt 3a and is inserted in the lock nut 23. The lubricating oil introducing passage 10 is opened vertically in the retainer member 28, the inlet of the lubricating oil introducing passage 10 is set in the receiving recess 26, and the outlet 11 is formed in the check valve chamber 12.
Communicate with each. The rocker arm chamber 2 is filled with the lubricating oil supplied through the lubricating oil passage of the forced lubrication device of the engine E, and is easily received in the lubricating oil receiving recess 26 of the lock nut 23. The ball valve body 17 is housed in the check valve chamber 12, and the biasing spring 29 biases the ball valve body 17 against the outlet 11 (that is, the valve opening 30) of the lubricating oil introducing passage 10 to urge the check valve chamber 12 to perform a check. When the hydraulic pressure in the valve chamber 12 becomes high, the valve opening 30 is closed. However, when the ball valve body 17 is manufactured from plastic or the like having a smaller specific gravity than the lubricating oil, the urging spring 2
9 can be omitted.

A lubricating oil storage chamber 14 is formed at a boundary portion 13 between the rocker arm pressing member 4 and a stud cap 22 fitted on the rocker arm pressing member 4, and the lubricating oil storage chamber 14 is formed into an L-shaped lubricating oil guide passage 15. To communicate with the check valve chamber 12 to guide the lubricating oil from the lubricating oil introduction passage 10 to the lubricating oil storage chamber 14 via the check valve chamber 12 and the lubricating oil guide passage 15, and at the same time, to the lubricating oil storage chamber. The lubricating oil from 14 is fed to the lubricating oil introducing passage 10
In addition, the ball valve element 17 of the check valve chamber 12 is configured to prevent reverse inflow. Further, the stud cap 22 forms the fitting insertion gap 18 into which the rocker arm pressing member 4 is fitted as the lubricating oil leak passage 16 from the lubricating oil storage chamber 14 to the rocker arm chamber 2 so that the hydraulic pressure of the lubricating oil storage chamber 14 is increased. Then, the lubricating oil in the lubricating oil storage chamber 14 is configured to leak from the leak passage 16 to the boat-shaped rocker arm 6. Further, the elastic pressure spring 8 is housed in the lubricating oil storage chamber 14 and is suspended over the upper wall of the stud cap 22 and the upper end wall of the rocker arm pressing member 4.
In this case, since the stud cap 22 is fixed to the stud bolt 3a by the lock nut 23, the rocker arm pressing member 4 is elastically biased downward B approaching the cylinder head 1 with respect to the stud bolt 3a by the action of the elastic spring 8. The valve clearance of the rocker arm 6 is always absorbed. Reference numeral 40 is a sliding stopper provided on the inner wall of the storage chamber of the stud cap 22.

Therefore, the function of the valve train of the first embodiment will be described. (1) At the time of low temperature such as when starting the engine E, the elastic spring 8
Since the rocker arm pressing member 4 is pressed downward B along the stud bolt 3a by the elastic force of, the rocker arm 6 contacting the rocker arm pressing member 4 from below is also pressed downward B and contacts the intake / exhaust valve 25. However, the valve clearance is absorbed. At this time, as the rocker arm 6 descends, the lubricating oil storage chamber 14 expands and is depressurized.
Check valve chamber 12 → lubricating oil storage chamber 1 via lubricating oil guide passage 15
Inflow to 4.

(2) When the temperature of the engine E rises and the intake / exhaust valve 25 and the push rod thermally expand, the rocker arm 6
Receives an upward force A and raises the rocker arm pressing member 4 with respect to the stud bolt 3a. Therefore, the lubricating oil storage chamber 14 is compressed, and the ball valve body 17 closes the outlet 11 of the lubricating oil introducing passage 10 by the hydraulic pressure transmitted from the lubricating oil guide passage 15 to the check valve chamber 12. The lubricating oil in the storage chamber 14 that has lost the escape path leaks from the lubricating oil leak passage 16 to the boat-shaped rocker arm 6. Therefore, the rocker arm 6 escapes upward A along the stud bolt 3a while absorbing the valve clearance, and the air intake / exhaust valve 25 does not open except during the intake / exhaust stroke. The engine E
When the intake / exhaust valve 25 contracts and the rocker arm 6 descends due to cooling, the lubricating oil is introduced into the lubricating oil introducing passage 10 as described in (1) above.
It is possible to make up for the leakage from the lubricating oil leakage passage 16 by flowing into the storage chamber 14 from the above.

2 and 3 show a second embodiment of the present invention,
It is a modified example of the basic structure of the first embodiment. That is, the lubrication oil passage 31 of the forced lubrication device 32 of the engine E is provided through the stud bolt 3a, and the lubrication oil passage 31 is formed in the first embodiment.
It is configured as the lubricating oil introduction passage 10. That is,
Lubricating oil introduction path 10 → Check valve chamber 12 → Lubricating oil guide path 15 →
The second embodiment is similar to the first embodiment in that the lubricating oil can be supplied to the lubricating oil storage chamber 14, but the lubricating oil mist filling the rocker arm chamber 2 is introduced from the introduction path 10. The second embodiment is different from the first embodiment in that the lubricating oil discharged from the forced lubrication device 32 is taken into the storage chamber 14.

In the second embodiment, a long rocker arm guide 33 is interposed between the stud cap 22 and the lock nut 23, and the arm 35 of the guide 33 is fitted into the guide hole 34 formed in the rocker arm 6 to form the rocker arm 6. Is configured to prevent rotational runout around the stud bolt 3a. The guide arm 35 is a rocker arm pressing member 4
It is formed in an arc shape along a concentric radius R centered on the spherical surface of the rocker arm 6 and is configured to fit the rocking locus of the rocker arm 6.

6 and 7 show a modified example for preventing the rotational runout of the boat-shaped rocker arm 6 separately from the second embodiment. That is, the boat-shaped rocker arm 6 is pressed into a skirt shape with a U-shaped cross section and an open bottom, and a rectangular / single-curved valve pad 36 is provided at the front of the rocker arm 6 and a hemispherical rod receiver 37 is provided at the rear thereof. There is no problem even if the rocker arm 6 is provided with a recess and the open / close valve 25 and the push rod 24 are fitted between the skirt portions 37 on both sides of the rocker arm 6 so that the rocker arm 6 can be prevented from swinging.

FIG. 4 shows a third embodiment of the present invention, which has the basic structure of the second embodiment, but is structured such that the stud cap 22 cannot be prevented from coming off with a stud bolt 3a having a head. That is, the third embodiment is similar to the second embodiment in that the lubricating oil passage 31 of the forced lubrication device of the engine E is used as the lubricating oil introduction passage 10 so that the lubricating oil can be supplied to the lubricating oil storage chamber 14. In contrast to the second embodiment in which the lock nut 23 is fastened to the headless stud bolt 3a, the third embodiment is different in that the lock nut is omitted by using the headed stud bolt 3a.

FIG. 5 shows the fourth embodiment, in which the rocker arm bracket 3b is screwed downward from the upper wall of the rocker arm cover 20, and the rocker arm pressing member 4 is slid up and down on the guide surface 39 below the rocker arm bracket 3b. The rocker arm pressing member 4 is provided with a lubricating oil storage chamber 14 on the inner periphery of the rocker arm pressing member 4, and the lubricating oil introducing passage 10 and the check valve chamber 1 are inserted from the forced lubricating oil passage 31 penetrating the rocker arm cover 20.
The lubricating oil is guided to the storage chamber 14 via the guide passage 39 and the guide surface 39 is configured as the lubricating oil leak passage 16.

That is, in contrast to Embodiments 1 to 3 in which the stud bolt 3a supporting the boat-shaped rocker arm 6 is erected upward from the cylinder head 1, in Embodiment 4 the rocker arm bracket 3b is replaced with the rocker arm bracket 3b instead of the stud bolt 3a. The difference is that it is erected downward from the cover 20, and since the lubricating oil storage chamber 14 is provided on the rocker arm pressing member 4 side, a large capacity of the storage chamber 14 can be formed. The check valve chamber 14 is connected to the rocker arm pressing member 4 and the bracket 3b.
Since it is provided at the boundary portion 13 with the lubricating oil storage chamber 14 and communicates directly with the lubricating oil storage chamber 14, the lubricating oil guide passage 15 of the first to third embodiments can be omitted. In addition, a through hole 41 is opened in the input portion 6a of the boat-shaped rocker arm 6 to guide the stored lubricating oil in the rocker arm 6 to the push rod 24, and a notch portion 43 is formed in the front wall near the output portion 6b of the boat-shaped rocker arm 6. Then open / close valve 2
5 is configured to guide the lubricating oil.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a main part of a valve train in a rocker arm chamber of a vertical overhead valve engine according to a first embodiment.

FIG. 2 is a view corresponding to FIG. 1 showing a second embodiment.

FIG. 3 is a plan view of a rocker arm showing a second embodiment.

FIG. 4 is a view corresponding to FIG. 1 showing a third embodiment.

FIG. 5 is a view equivalent to FIG. 1 showing a fourth embodiment.

FIG. 6 is a vertical cross-sectional view of a rocker arm showing a modified example of preventing rotation shake of the rocker arm.

FIG. 7 is a perspective view of a rocker arm showing the modification.

FIG. 8 is a vertical cross-sectional view around a rocker arm chamber of a vertical overhead valve engine showing a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylinder head 2 Rocker arm chamber 3 Stud member 4 Rocker arm pressing member 5 4 receiving surface of 4 6 Boat rocker arm 7 6 abutting surface 8 Repression spring 10 Lubricating oil introduction path 11 10 exit 12 Check valve chamber 13 4 side boundary Part 14 Lubricating oil storage chamber 15 Lubricating oil guide passage 16 Lubricating oil leak passage 17 Check valve body of 12 18 Insertion gap of 3 and 4 E Overhead valve engine P Vertical direction A Upward B Downward

Claims (1)

Claims: 1. A rocker arm chamber of an overhead valve engine (E).
Attach the stud member (3) to (2), and attach the stud member (3).
The rocker arm pressing member (4) is inserted and supported so as to be able to move back and forth along the vertical direction (P) approaching and separating from the cylinder head (1), and the rocker arm pressing member (4) has a partially spherical receiving surface (5). The rocker arm (6) is formed by sheet metal into a boat shape with a U-shaped cross section, and the boat-shaped rocker arm (6) is provided with a partially spherical pressing surface (7), and the pressing surface (7) is formed. The cylinder head is attached to the receiving surface (5) of the rocker arm pressing member (4).
The boat-shaped rocker arm is brought into surface contact from the lower side facing (1).
In a boat-type rocker arm type valve operating device of an overhead valve engine in which (6) is swingably supported by a rocker arm pressing member (4), the rocker arm pressing member (4) is attached to the stud member (3) via a spring (8). The rocker arm pressing member (4) is elastically biased downward (B) toward the cylinder head (1) against the stud member (3) by the elastic spring (8), and the stud member (3) is lubricated with lubricating oil. Inlet passage (10) and check valve chamber (1
2) is provided, the outlet (11) of the lubricating oil introduction passage (10) communicates with the check valve chamber (12), and the boundary portion (13) between the stud member (3) and the rocker arm pressing member (4) side Lubricating oil storage chamber (1
4) is provided, the lubricating oil storage chamber (14) is communicated with the check valve chamber (12), and the lubricating oil from the lubricating oil introduction path (10) is fed to the check valve chamber (12).
The lubricating oil from the lubricating oil storage chamber (14) is guided to the lubricating oil storage chamber (14) through the lubricating oil introduction passage
The valve body (17) of the check valve chamber (12) is configured to prevent reverse inflow in (10), and the fitting gap (18) between the rocker arm pressing member (4) and the stud member (3) side is lubricated. When the rocker arm (6) is formed as a lubricating oil leak passage (16) from the oil storage chamber (14) to the rocker arm chamber (2), and the rocker arm (6) receives an upward force (A) away from the cylinder head (1), the rocker arm presser foot is pressed. The member (4) moves upward (A) with respect to the stud member (3), the lubricating oil storage chamber (14) is compressed, and the check valve body (1) of the check valve chamber (12) is
7) closes the outlet (11) of the lubricating oil introduction passage (10), leaks lubricating oil from the lubricating oil storage chamber (14) to the rocker arm chamber (2) through the lubricating oil leak passage (16), and (6)
Is configured to be movable upward (A) along a stud member (3). A boat-type rocker arm type valve operating device for an overhead valve engine.