JPS62276207A - Locker arm - Google Patents

Abstract

PURPOSE:To prevent the air from intruding into a hydraulic lash-adjuster, by soaking a sealing boot, which is provided to a sealed-type, hydraulic lash- adjuster, in an oil chamber. CONSTITUTION:A sealed-type, hydraulic lash-adjuster 17 is provided to an end of a locker arm driven by a cam 4. The lash-adjuster 17 consists of a plunger body 20, which is fixed to the locker arm 7, a plunger 23, which slides within the plunger body 20, and a boot 23, which connects the lower end of the plunger 23 and the plunger body 20 to a sealed state. The boot 32 is placed in an oil chamber 38 provided to the locker arm 7, while the oil is constantly supplied to the oil chamber 38 from the top 11 of the locker arm 7. With this contrivance, the boot 32 is constantly soaked in oil, thereby preventing the air from intruding into the lash adjuster 17.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a rocker arm used in a valve train of a four-stroke engine, which has a built-in sealed hydraulic lash adjuster, The present invention relates to a device that can automatically adjust clearance, etc., and particularly relates to a rocker arm advantageously formed with an oil chamber for soaking boots in oil.

[Prior Art] Lash adjusters are used in high-performance engines to automatically adjust tappet clearances and valve clearances to always maintain zero in valve train systems.As an example of a sealed hydraulic lash adjuster, there is a There is one described in Sho 60-13908. This sealed hydraulic lash adjuster includes a bottomed cylindrical plunger, a plunger body that is fitted inside the plunger and forms a high pressure chamber between the plunger and the plunger, and a return that energizes a check valve and plunger inside the high pressure chamber. Install a spring,
Furthermore, a diaphragm boot is arranged between the plunger and the plunger body to define a reservoir chamber, and the reservoir chamber and the high pressure chamber are communicated through a check valve. This sealed hydraulic lash adjuster is built into one end of the rocker arm, with the tip of the plunger in contact with the end of the valve stem, and the other end of the rocker arm in contact with the cam. Note that the component names used here are the same as those of the embodiments described later.

When a sealed hydraulic lash adjuster is used in this type, the plunger automatically slides against the plunger body following the operation of the cam and rocker arm, so valve clearance etc. are automatically adjusted. Quiet and efficient zero-rush operation is achieved. Also dense
When the -+ type hydraulic lash adjuster is built into the end of the rocker arm, the component configuration becomes simpler and the integration error due to all the components is reduced accordingly. As a result, the amount of adjustment of the sealed hydraulic lash adjuster can be reduced, and the entire device can be made more compact.

[Problems to be Solved by the Invention] By the way, in a sealed hydraulic lash adjuster that has a boot around it, it is desirable to soak the boot in oil to prevent air from entering the hydraulic oil in the reservoir chamber through the boot. . For this reason, when a sealed hydraulic lash adjuster is provided within the block of the cylinder head, an oil chamber can also be provided at the same time relatively easily, so it is conceivable to immerse the boot in oil. However, for the sealed hydraulic lash adjuster built into the rocker arm, which is a part that swings at high speed, there is no one yet that has the boot soaked in oil. Therefore, the present invention provides a rocker arm with a built-in sealed hydraulic lash adjuster.
It provides an oil chamber in which boots can be soaked in oil.

[Means for Solving the Problems] The rocker arm of the present invention has the following configuration. That is, in a rocker arm in which a sealed hydraulic lash adjuster is housed in a storage chamber provided at one end, the sealed hydraulic lash adjuster has a boot liquid-tightly fixed around it, and a tip of the sealed hydraulic lash adjuster. The opening of the storage chamber is closed so as to protrude from the storage chamber to form an oil chamber, and the boot is immersed in oil filled inside the chamber.

[Operation of the Invention] The rocker arm according to the present invention has a storage chamber formed at one end thereof, and a sealed hydraulic lash adjuster is stored in the storage chamber. Further, a boot is fluid-tightly fixed around the sealed hydraulic lash adjuster, and the boot is immersed in oil filled in an oil chamber formed in the storage chamber. Therefore, even if the sealed hydraulic lash adjuster swings at high speed together with the rocker arm, the boot is always submerged in oil, preventing air from entering the reservoir chamber through the boot.

[Embodiment] FIG. 1 shows a valve train for a motorcycle engine according to an embodiment of the present invention. This valve train is of an overdrive cam (OHC) type and is provided within the cylinder head 1. The cylinder head 1 is composed of a cylinder head main body 2 and a head cover 3. The camshaft 4 is located approximately in the middle of the cylinder head l, and the valve 5 on the intake side
and the exhaust side valve 6. However, the camshaft 4 in the figure is shown as a locus circle of the base circle of the cam formed around it. Rocker arms 7.8 are in contact with the camshaft 4, respectively, and the approximately central portion in the longitudinal direction thereof is a swing fulcrum 9.1 that is pivotally supported by the rocker shaft.
Make 0. The rocker arm 7.8 is swingably supported around a swing fulcrum 9.10. When the camshaft 4, which abuts one end of the rocker arm 7.8, rotates, the valves 5 and 6, which abut the other end, open and close at predetermined timing. An oil sump chamber 11 is located above the portion of the rocker arm 7.8 supported by the swing fulcrum 9.10.
．． 12 are provided. Further, a storage chamber 13.14 is formed at the other end of the rocker arm 7.8, and an oil passage 15 is formed at an inclined angle to penetrate the oil reservoir chamber 11.12.
．． 16. A sealed hydraulic lash adjuster 17.18 is also accommodated in the storage chamber 13.14, a portion of which protrudes and is in direct contact with the stem end of the valve 5.6. Note that 19 is a block to which the rocker shaft is attached.

Next, the detailed structure of the sealed hydraulic insurance adjuster and its supporting portion will be explained based on FIG.

Note that, regarding the sealed hydraulic lash adjuster, the rocker arm 7 side and the rocker arm 8 side have completely the same structure, so only the rocker arm 7 side will be described below, and the 8 side will be omitted. The sealed hydraulic lash adjuster 17 includes a bottomed cylindrical plunger body 20 and a plunger 23 that forms a high pressure chamber 22 between the plunger body 20 and the bottom 21 and is slidably fitted therein. The plunger 23 is extended from the plunger body 20 by a return spring 24 made of a coil spring (
The head 25 has a hemispherical shape and protrudes from the plunger body 20. Further, in the axial direction of the plunger 23, a communication passage 27 is formed through the head 25 and is hermetically plugged with a plug 26. A check valve is provided at the opening of the communication passage 27 on the high pressure chamber 22 side.

The check valve is a known one, and includes a ball gauge 29 attached around the opening of the communication passage 27 by a fixed ring 28, and a ball 31 pressed against the opening of the communication passage 27 by a spring 30 inside the ball gauge 29. Consisting of Note that the spring 3o presses against the ball 31 with a weak set load. This check valve allows the hydraulic oil to
When the pressure in the high pressure chamber 22 is high, it is regulated so that it does not flow out from the high pressure chamber 22. Further, a boot 32 made of a diaphragm made of rubber or the like is provided between the tip of the plunger body 20 and the head 25 of the plunger 23. The plunger body 20 side of the boot 32 is fluid-tightly fixed around the plunger body 20 by a retainer 33, and the boot 32
The head 25 side is also liquid-tightly fixed to the side of the head 25 by a retainer 34. A reservoir chamber 35 having a variable volume is formed between the plunger body 20 and the plunger 23 inside the boot 32. Further, a communication passage 36 is formed across the plunger 23 to communicate the reservoir chamber 35 and the communication passage 27. Therefore, the change in the volume of the hydraulic oil in the high pressure chamber 22 due to the sliding of the plunger 23 is absorbed by the elastic deformation of the boot 32 and the resulting change in the volume of the reservoir chamber 35.

The inside of the storage chamber 13 has a small-diameter upper portion having an inner diameter approximately equal to the outer diameter of the plunger body 20, into which the bottom portion 21 of the plunger body 20 is fitted. on the other hand,
The inside lower part of the storage chamber 13 has a stepped large diameter part 37, and the inner diameter of this part is larger than that of the plunger body 20, and a space is formed between the large diameter part 37 and the plunger body 20. This space is an oil chamber 38 filled with oil.
It becomes. The boots 32 are housed in the oil chamber 38 and soaked in oil in the oil chamber 38.

Further, the bottom of the oil chamber 38 is sealed by a bottom 39. The bottom 39 is open at its center, from which the top of the plunger head 25 protrudes and abuts against the stem end 5a of the valve 5. Note that when the head 25 of the plunger expands and contracts in the vertical direction in the figure, the tip of the retainer 34 slides against the opening of the bottom 39. On the other hand, the oil chamber 38 communicates with the bottom of the oil reservoir chamber 11 through the oil passage 15. Therefore, the oil stored in the oil reservoir chamber 11 is constantly supplied into the oil chamber 38 through the oil passage 15. At this time, the amount of oil lost from the sliding portion is much smaller than the amount of oil supplied from the relatively large diameter oil passage 15, so the oil chamber 38 is always filled with oil.

Therefore, since the boot 32 is immersed in oil filled in the oil chamber 38 provided in the storage chamber 13, the sealed hydraulic lash adjuster 17 along with the rocker arm 7
Even if the boot 32 swings at high speed, the boot 32 can remain immersed in oil at all times. This effectively prevents air from entering the hydraulic oil in the reservoir chamber 35 through the boot 32. In this embodiment, since the oil reservoir chamber 11 is provided above the swing fulcrum 9, that is, the center of swing of the rocker arm 7, the oil in the cam chamber is always stored in the oil reservoir chamber 11. Furthermore, even if the rocker arm 7 swings at high speed, the oil reservoir chamber 11 is located above the swing fulcrum 9, so that the amount of oil stored therein is dissipated to a minimum. Therefore, the amount of oil supplied to the oil chamber 38 can be ensured. Moreover, since the oil passage 15 in this embodiment is inclined upward toward the oil reservoir chamber 11, the oil containing a large amount of air bubbles stored in the oil reservoir chamber 11 flows down the oil passage 15. This is advantageous because oil with fewer air bubbles is supplied to the oil chamber 38.

Here, the operation of the sealed hydraulic lash adjuster 17 will be outlined. In FIG. 2, the head 25 of the plunger 23 is initially pressed directly against the stem end 5a of the valve 5 only by the force of the return spring 24, making the valve clearance zero. Then, when the camshaft 4 rotates and pushes up the rocker arm 7, the storage chamber 13 is swung diagonally downward and to the right in the figure. Then, the inside of the high pressure chamber 22 is pushed by the plunger 23 and suddenly becomes high pressure, so the ball 31 seals the opening of the communication passage 27 and stops the flow of hydraulic oil. Therefore, the plunger body 20 of the plunger 23
The sliding movement against the rocker arm 7 stops, and the stem end 5a is strongly pressed together with the rocker arm 7 by hydraulic pressure. Thereafter, the camshaft 4 rotates further and when the push-up against the rocker arm 7 is no longer caused, the plunger 23 becomes slidable again and the valve clearance is automatically adjusted to a state of zero lash. The adjustment amount of the plunger 23 includes accumulated errors of the camshaft 4, rocker arm 7, valve 5, and sealed hydraulic lash adjuster 17 itself. However, by incorporating the sealed hydraulic lash adjuster 17 into the rocker arm 7, the number of components that cause this integration error is relatively reduced.
The accumulation error is reduced accordingly, and the amount of adjustment of the sealed hydraulic lash adjuster 17 can be reduced accordingly.

Note that the present invention is not limited to the above-mentioned embodiment, and is not limited to a single overhead cam type valve train, for example, and is not limited to a single overhead cam type valve train. Needless to say, the present invention can be applied to an over-radio cam system, and also to an OHV (overhead valve) system. Further, the relationship between the plunger and the plunger body of the sealed hydraulic lash adjuster is relative, and the plunger may be fitted into the oil chamber and the plunger body may be slidably fitted.

[Effects of the Invention] The rocker arm according to the present invention has a sealed hydraulic lash adjuster built into one end thereof, and the storage chamber of the sealed hydraulic lash adjuster is filled with oil to form an oil chamber. The adjuster's boots can be soaked in oil at all times. Therefore, even in high-speed swinging members such as rocker arms, it is possible to have a structure in which a sealed hydraulic lash adjuster is built in and the boot is soaked in oil. As a result, it is possible to prevent air from entering the hydraulic oil in the reservoir chamber through the boot, thereby improving the reliability in the operation of the sealed hydraulic lash adjuster.

[Brief explanation of the drawing]

1 and 2 show an embodiment of the present invention, in which FIG. 1 is a sectional view showing a valve train portion of an engine, and FIG. 2 is a sectional view of a main part. (Explanation of symbols) 4...Camshaft (trajectory circle), 5, 6...Valve, 7, 8...Rocker arm, 13, 14...Storage chamber, 17, 18...Sealed type Hydraulic lash adjuster.

Claims (2)

[Claims] (1) In a rocker arm in which a sealed hydraulic lash adjuster is stored in a storage chamber provided at one end, the sealed hydraulic lash adjuster has a boot liquid-tightly fixed around it, and the sealed hydraulic lash adjuster A rocker arm characterized in that the opening of the storage chamber is closed to form an oil chamber so that the tip portion protrudes, and the boot is immersed in oil filled inside the chamber. (2) The rocker arm described in claim (1) has an oil reservoir chamber oil bath formed above its swing fulcrum, and communicates the oil reservoir chamber with the storage chamber. Features a rocker arm.