JPH075203Y2 - Hydraulic lash adjuster - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention relates to a hydraulic lash adjuster, and more specifically to a semi-solid sealing material at an oil inlet for introducing oil from the outside into the lash adjuster. The present invention relates to a hydraulic lash adjuster filled with.

(Prior Art) Hereinafter, a general operation of the lash adjuster according to the present invention will be described.

In general internal combustion engines, it is necessary to provide a valve clearance in consideration of the difference between the expansion of the cylinder head and the expansion of the valve operating mechanism due to heat, but if this valve clearance is not appropriate, noise will be generated during engine operation. Or a loss of horsepower may occur due to blown raw gas. A hydraulic lash adjuster is known as a means for solving such a problem. The hydraulic lash adjuster always keeps the valve clearance at zero during operation of the valve operating mechanism.
It absorbs changes in expansion due to temperature, prevents noise and blowout of raw gas, and realizes stable operation of the valve operating mechanism.

In the valve mechanism, the cam shaft is arranged in the cylinder head, and the cylinder block has an OHC type and a cam shaft that directly drive the intake and exhaust valves with or without a rocker arm.
There is an OHV type that drives an intake / exhaust valve via a push rod and rocker arm. Whether the OHC type or the OHV type, when the engine is operating, the hydraulic lash adjuster and the intake / exhaust valve move integrally according to the rotation of the cam.

When the engine is stopped, the cam abuts the cam surface at an arbitrary position on the upper surface of the hydraulic lash adjuster directly or indirectly via the swing arm. Therefore, when the cam nose (protruding part of the cam surface) directly or indirectly contacts the upper surface of the hydraulic lash adjuster,
Since the urging force of the valve spring that urges the intake and exhaust valves to the closed position is relatively large, the entire hydraulic lash adjuster is
Mainly the axial pressure is always applied. Therefore, if this stopped state continues for a long time, the oil in the high pressure chamber gradually leaks from the gap between the body of the lash adjuster and the plunger, and finally the high pressure chamber is in the most crushed state, that is, the volume of the high pressure chamber becomes the minimum. It becomes a state (so-called “bottom state”).

Then, when the engine is restarted, the volume of the high pressure chamber of the hydraulic lash adjuster stopped at the cam nose position increases, the high pressure chamber becomes negative pressure, the check ball opens, and oil is sucked from the reservoir to the high pressure chamber. When the pressure in the high-pressure chamber reaches a predetermined pressure (pressure during normal operation) again, the check valve closes. In this state, the hydraulic lash adjuster will perform a normal expansion / contraction operation. Acting in this manner, the hydraulic lash adjuster automatically adjusts to properly fill any gaps and properly seat the valve. As a result, noise generation can be eliminated.

(Problems to be solved by the invention) In the lash adjuster having the above-described function, after the low viscosity oil is filled during the lash adjuster assembly, shipping, transportation, assembly to the engine, that is, the cylinder head, and further starting. Work is going on.

In the process of such work, the oil introduction port that communicates the inside of the lash adjuster with the outside is always open as compared with the conventional one, so a considerable amount of oil is filled in the lash adjuster during shipping and transportation, It leaks to the outside, and when the lash adjuster starts, there is not enough oil inside,
In particular, when starting from the cam nose, it is easy to suck air from the outside, and as a result, abnormal noise may occur.

That is, the conventional one has the following drawbacks.

During the transportation, oil leaks from the reservoir chamber of the lash adjuster, the oil inside leaks to the outside from the oil introduction port provided in the lash adjuster body, and instead air enters the reservoir chamber. Therefore, in this state, if the cam nose starts at the time of starting immediately after mounting to the cylinder head, air is rapidly sucked into the high pressure chamber from the reservoir chamber immediately after the start via the oil passage in the cylinder head, and the high pressure chamber becomes rigid. A so-called "sponge state" cannot be maintained, and it may not be possible to follow the displacement of the cam and an abnormal noise may be generated.

In order to solve the above-mentioned drawbacks of the conventional ones, for example, a hydraulic valve clearance adjusting device disclosed in JP-A-62-13706.
That is, a lash adjuster has been proposed.

In this conventional technique, an oil having a viscosity lower than that of engine oil is filled in a high pressure chamber that is crushed when it is assembled to a cylinder head, and an oil having a viscosity higher than that of an oil filled in the high pressure chamber is filled in a reservoir chamber. is doing. With this configuration, the high-pressure chamber is easily crushed during the assembling, the assembling is facilitated, and the leakage of oil to the outside of the lash adjuster can be prevented.

However, in the lash adjuster disclosed in the above-mentioned JP-A-62-13706, since the oil in the reservoir chamber has a high viscosity, leakage of the oil in the lash adjuster to the outside can be prevented to some extent, but the lash adjuster is not always necessary. It is not used in a vertical position, but when mounted in a V-type engine, for example, it is used with some inclination. In this case, the enclosed oil in the lash adjuster leaks out spontaneously.To prevent this, it is necessary to use oil with a considerably high viscosity. It is practically difficult due to the time.

The lash adjuster is subjected to a leak down test as a performance test before shipment. The leak down test is a measure of how much oil leaks to the outside from the gap between the lash adjuster body and the plunger assembly between the extended position of the lash adjuster and the bottom of the high pressure chamber. It is a test. When the viscosity of the enclosed oil in the high pressure chamber and the reservoir chamber is changed as disclosed in the above publication,
After the leak down test, it is necessary to refill the reservoir chamber with high-viscosity oil, which may be a troublesome work for refilling the oil and assembling the lash adjuster.

From the above, the purpose of the present invention is to transfer the oil enclosed in the lash adjuster from the oil inlet to the outside during transportation with a simple structure or when it is assembled to the cylinder head and before the engine is started. (EN) A hydraulic lash adjuster capable of preventing leakage and, as a result, preventing intake of air into the lash adjuster, particularly into the high pressure chamber.

(Means for Solving the Problems) In order to achieve the above-mentioned object, the hydraulic lash adjuster of the present invention is held in the cylinder head and transfers the rotational displacement of the cam to the intake / exhaust valve without generating a valve clearance. In the hydraulic lash adjuster (10; 50) that transmits, the oil inlet (1a; 51a) for introducing engine oil from the passage (29; 70) carved in the cylinder head, and the oil inlet when operating Reservoir chamber (15; 67) to which engine oil is replenished from the high pressure chamber (11; 67) communicating with the reservoir chamber via valve means (5,6,7,8,; 56,57,59,58). 66), wherein the reservoir chamber and the high-pressure chamber are filled with oil in advance, and the oil inlet is sealed with a semi-solid sealing material (14; 65). There is.

(Operation) With the above-mentioned configuration, the oil filled in the lash adjuster does not leak to the outside during transportation or during the period from assembly to the cylinder head to the start of the engine. It is possible to prevent air from being sucked into the adjuster.

(Embodiment) Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is an axial sectional view showing an embodiment in which the present invention is applied to an end pivot type hydraulic lash adjuster (hereinafter, “hydraulic type” is abbreviated as “lash adjuster”). Note that FIG. 1 shows a state in which the lash adjuster 10 has been assembled.
An enclosed oil such as spindle oil is enclosed in the inside of the. Further, FIG. 1 shows the lash adjuster 10 in its most extended state. Lash adjuster
Reference numeral 10 denotes a substantially cylindrical cup-shaped body 1 having an upper opening, a substantially cylindrical plunger 3 slidably fitted in the body 1, and a plunger fitted in the body 1 above the plunger 3. It consists of a cap 2.

The plunger cap 2 is provided with an oil ejection port 2a at its tip and is held by a cap retainer 4 so as not to come off from the body 1. The plunger 3 and the plunger cap 2 slide integrally.

A wall portion 3a, which divides the inside of the body 1 into two spaces and is provided with an orifice 5, is provided in the middle of the plunger 3 in the axial direction.
There is a high pressure chamber between the wall 3a and the bottom of the body 1.
11 are defined. In the high pressure chamber 11, a check ball 6 seated on the orifice 5, a retainer spring 8 for biasing the check ball 6 to seat on the orifice 5,
A retainer 7 that holds the check ball 6 and the retainer spring 8 and a plunger spring 9 that abuts the retainer 7 against the wall portion 3a and biases the plunger 3 toward the plunger cap 2 side are mounted.

A reservoir chamber 15 is defined between the wall portion 3a of the plunger 3 and the plunger cap 2 on the side opposite to the high pressure chamber 11.
Therefore, the orifice 5, the check ball 6, the retainer 7 and the retainer spring 8 constitute a valve means for partitioning the high pressure chamber 11 and the reservoir chamber 15, and the check is performed according to the pressure difference between the high pressure chamber 11 and the reservoir chamber 15. The ball 6 opens and closes the orifice 5 to introduce a predetermined amount of oil from the reservoir chamber 15 into the high pressure chamber 11.

A through hole 13 is provided in the cylindrical portion of the plunger cap 2 fitted into the body 1. Therefore, the oil such as engine oil introduced from the oil passage 29 provided in the cylinder head shown in FIG. 2 passes through the annular groove 12 formed in the inner peripheral surface of the body 1 and passes through the annular groove 12 of the body 1. It is introduced into the reservoir chamber 15 from the oil introduction port 1a provided on the outer peripheral surface.

In the lash adjuster 10 shown in FIG. 1, the high pressure chamber 11 and the reservoir chamber 15 are respectively filled with filled oil as described above, and in this state, the oil introduction port 1a is filled with the sealing material 14, The oil inlet 1a is sealed. Therefore, this sealing material
14 prevents oil from leaking from the reservoir chamber during shipping and transportation. Here, the sealing material 14 is a semi-solid substance, and for example, grease or vaseline can be used. However, the sealing material 14 has such a viscosity that the enclosed oil in the lash adjuster 10 does not leak out from the oil introduction port 1a to the outside from the assembling of the lash adjuster 10 to the cylinder head. It is necessary to have a sufficient adhesive force to surely adhere. Also, the sealing material 14 is pressed by the engine oil pressure-fed from the oil introduction port 1a when the engine is started, and the oil introduction port 1a
It is necessary to have the property of falling off from. Further, as in the second embodiment described later, the most preferable sealing material used in the present invention is a grease composed of a base oil that is easily soluble in engine oil, that is, compatible with the engine oil. ..

The oil pre-filled in the lash adjuster 10 is
Since a low viscosity oil is preferable to engine oil (having a kinematic viscosity of about 60 cSt at 40 ° C.), for example, spindle oil (having a kinematic viscosity of about 3 cSt at 25 ° C.) or light oil is used. This is because when the lash adjuster is assembled to the cylinder head, the assembly work time can be shortened due to the low viscosity. Further, since the oil is sealed in advance, it is possible to assemble the oil (usually low viscosity oil) used in the leak down test as it is in the cylinder head.

Next, referring to FIG. 2, the lash adjuster of the present embodiment.
The operation when the 10 is assembled to the cylinder head will be described. The cylinder head shown in FIG. 2 is a V-type engine and therefore is inclined, but it goes without saying that it can also be used for other types of engines. Further, the lash adjuster 10 is shown in FIG. 2 in a “bottomed state” in which the high pressure chamber 11 is most crushed. As can be clearly seen from FIG. 2, it is expected that a considerable amount of oil will leak from the lash adjuster 10 assembled in the cylinder head at an inclination until the engine starts.

A substantially cylindrical pocket 28 provided on the cylinder head 30
The lash adjuster 10 is fitted in. Pocket 28
An oil passage 29 through which engine oil or the like is introduced is provided at a position corresponding to the oil introduction port 1a of the body 1. The tip of the plunger cap 2 is in contact with one end of the swing arm 20. A cam 21 rotatably supported by a rotary shaft 23 is rotatably in contact with a surface 20b of the swing arm 20. In FIG. 2, the cam nose 22 of the cam 21 is
It is shown in a state in which it is in contact with the surface 20b and stopped. Since a through hole 20a is provided at one end of the swing arm 20 that abuts the plunger cap 2, the engine oil that has passed through the lash adjuster 10 is provided so as to face the oil jet port 2a. Cam face and face 2 through 20a
Lubricate the sliding surface with 0b.

One end of the intake / exhaust valve 24 is engaged with the other end of the swing arm 20. The intake / exhaust valve 24 has an intake / exhaust port formed by a valve spring 25.
Biased to close 27. FIG. 2 shows a state in which the cam nose 22 is in contact with the swing arm 20 in a so-called “when the cam nose is stopped” state immediately after the lash adjuster 10 is assembled to the cylinder head 30.
In this state, when the engine is started, the lash adjuster 10 rapidly expands and sucks the air in the oil passage 29 from the oil passage 29 via the oil introduction port 1a, but the oil introduction port 1a Since the sealing material 14 is filled, there is no sudden suction of air into the lash adjuster 10 at that time, and at least suction of air into the high pressure chamber 11 is prevented.

After the engine is started, after a predetermined time has elapsed, in order to introduce the engine oil into the lash adjuster 10, the oil introduction port 1a must be opened, but as described above, the sealing material 14 is a semi-solid material. Since it is a substance in the shape of a cylinder, if a certain amount of force is applied by the engine oil that is pumped,
It falls off from the oil inlet 1a. Therefore, the operation of the lash adjuster 10 after the start of engine operation is not hindered. In particular, if the sealing material 14 is compatible with the engine oil, it will be completely mixed with the engine oil, which is even more convenient.

Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 3 shows a reverse bucket type lash adjuster 50 used in an engine of a type in which a cam directly opens and closes an intake / exhaust valve via a lash adjuster. Second
Also in the embodiment, the engine is a V-type engine having a predetermined inclination.

The lash adjuster 50 is fitted in a hole provided in the cylinder head 62. The lash adjuster 50 has a substantially cylindrical cup-shaped follower 51 that is fitted into the cylinder head 62 and has a downward opening, an annular spacer member 53 fixed in the follower 51, and an axial slide on the spacer member 53. It is composed of a substantially cylindrical cup-shaped body 52 which is held freely and is opened upward, and a plunger 54 which is fitted in the body 52 so as to be slidable in the axial direction. The code
Reference numeral 61 is a retainer for preventing the body 52 from dropping downward.

A wall portion 55, which divides the inside of the body 52 into two spaces and is provided with an orifice 56, is provided in the middle of the plunger 54 in the axial direction.
There is a high pressure chamber between the wall 55 and the bottom of the body 52.
66 are defined. In the high pressure chamber 66, a check ball 57 seated on the orifice 56, and a retainer spring 58 for biasing the check ball 57 to seat on the orifice 56,
Retainer 59 holding check ball 57 and retainer spring 58, and retainer 59 against wall 55,
A plunger spring 60 for urging the member 54 toward the opening of the body 52 is mounted.

A follower is provided on the opposite side of the wall 55 of the plunger 54 from the high pressure chamber 66.
A reservoir chamber 67 is defined between the upper inner peripheral surface of 51 and the inner peripheral surface. Therefore, the orifice 56, check ball 57, retainer
59 and the retainer spring 58 constitute valve means for partitioning the high pressure chamber 11 and the reservoir chamber 15, and the high pressure chamber 66 and the reservoir chamber
Depending on the pressure difference with 67, the check ball 57
By opening and closing 56, a predetermined amount of oil is introduced from the reservoir chamber 67 into the high pressure chamber 66.

The cylinder head 62 is provided with an oil passage 70 for introducing engine oil or the like into the lash adjuster 50, and the engine oil from the oil passage 70 is formed into an annular shape engraved on the outer peripheral surface of the follower 51. It is introduced into the lash adjuster 50 from an oil introduction port 51a penetrating the outer peripheral surface of the follower 51 through the groove 71. Follower 51, spacer member 53, and body
An annular replenishment chamber is formed between the oil supply port 52 and 52, into which the oil initially introduced from the oil introduction port 51a enters. The oil introduced into the supply chamber 68 passes through the communication passage 69 formed in the inner peripheral surface of the upper portion of the follower 51 and is introduced into the reservoir chamber 67. Oil inlet
51a is filled with a sealing material 65 having the same function as in the first embodiment.

The tip of the intake / exhaust valve 63 is in contact with the lower surface of the body 52. The intake / exhaust valve 63 is biased by a valve spring 64 in a direction of closing an intake / exhaust port (not shown).

The cam surface of the cam 71 rotatably supported by the cam shaft 73 is in contact with the upper surface of the follower 51. In the case of FIG. 3, the cam nose 72 is replaced by the follower 51 as in the case of FIG.
Has stopped while being in contact with the upper surface of the.

The operation of the lash adjuster 50 at the time of starting the engine is the same as that of the first embodiment including the function of the sealing material, and therefore will not be described again here. Further, as is apparent from FIG. 3, in the case of the present embodiment as well, as in the first embodiment, the lash adjuster 50 is inclined and assembled in the cylinder head.
The sealing material 65 prevents leakage of the enclosed oil from 50 until the engine is started.

In each of the embodiments shown in FIGS. 2 and 3,
Although the lash adjuster is arranged in the V-type engine having the inclined engine cylinder, it goes without saying that the lash adjuster can be used not only in the V-type engine but also in a normal vertical engine.

(Effect of the Invention) According to the hydraulic lash adjuster of the present invention described above, the following effects can be obtained.

It is possible to prevent the enclosed oil in the lash adjuster from leaking to the outside from the time of shipment, the time of transportation, or the time of assembling to the cylinder head to the time when the engine is started. Further, it is possible to mitigate a sudden intake of air at the time of starting the cam nose.

As a result, it is an object of the present invention to provide a hydraulic lash adjuster that can prevent air from being sucked into the lash adjuster, particularly into the high pressure chamber immediately after the engine is started after being assembled.

Therefore, it is possible to provide the lash adjuster which maintains the rigidity in the high pressure chamber and is stable in operation.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the hydraulic lash adjuster of the present invention, and FIG. 2 is a sectional view showing an engine head in which the hydraulic lash adjuster of the above embodiment is incorporated. The drawing is a cross-sectional view showing a hydraulic lash adjuster of a second embodiment of the present invention assembled in a cylinder head. [Explanation of symbols for main parts] 1,52 …… Body 1a, 51a …… Oil inlet 3,54 …… Plunger 15,67 …… Reservoir chamber 11,66 …… High pressure chamber 6,57 …… Check ball 14 , 65 …… Sealant 10,50 …… Hydraulic lash adjuster

Claims (4)

[Scope of utility model registration request] 1. In a hydraulic lash adjuster which is held in a cylinder head and transmits a rotational displacement of a cam to an intake / exhaust valve without generating a valve clearance, engine oil is introduced from an oil passage engraved in the cylinder head. A reservoir chamber to which engine oil is replenished from the oil inlet port during operation, and a high pressure chamber communicating with the reservoir chamber via valve means. Is a hydraulic lash adjuster characterized in that it is filled with oil in advance and the oil inlet is sealed with a semi-solid sealing material. 2. The hydraulic lash adjuster according to claim 1, wherein the oil previously filled in the reservoir chamber and the high-pressure chamber has a lower viscosity than engine oil introduced from an oil inlet. . 3. The hydraulic lash adjuster according to claim 1, wherein the sealing material is made of grease or petrolatum. 4. The hydraulic lash adjuster according to claim 1, wherein the sealing material is made of a material compatible with engine oil.