JPH034727Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a bucket type hydraulic lash adjuster belonging to an automatic tappet clearance correction device for an internal combustion engine.

If air mixed in the lubricating oil enters the high pressure chamber of the bucket type hydraulic lash adjuster, it will impair its function, so it must be eliminated. However, providing a special air separation device for this purpose has the disadvantage of complicating the device. In view of this point, the present invention is characterized in that a ventilation hole is provided in the top plate of the upper part of the bucket for the purpose of venting air.

With this invention, the air mixed in the lubricating oil is automatically released to the outside air during operation, which often impairs the function of the high-pressure chamber.Moreover, the structure is simplified because no special air separation device is required. be.

However, simply providing ventilation holes causes the following disadvantages.

(1) Lubricating oil pressure decreases.

(2) When starting the dry lash (when the lash adjuster stops at the position pushed by the cam nose, the volume of the high pressure chamber becomes minimum and the system starts from that state), air is sucked through the hole and introduced into the high pressure chamber. do.

The purpose of this invention is to vent air from the reservoir chamber of a bucket-type hydraulic lash adjuster during operation and to provide good lubrication between the cam and the bucket. A check chamber is provided outside the top plate, a check ball or a check plate is housed in the check chamber together with a check spring as required, and a retainer or cage is provided to face and seal the check ball or check plate.

Figure 1 shows the first example of implementing the present invention.
is the cylinder head, 2 is the cam, 3 is the engine valve, 4 is the bucket, 5 is the cylinder, 6 is the piston, 7 is the check ball, 8 is the check spring, 9 is the retainer, 10 is the check chamber, 11 is the orifice, 12, 13 is a reservoir chamber, 14 is a high pressure chamber, and 15 is a top plate. In the above configuration,
When the lubricating oil pressure becomes greater than the check spring load (cracking pressure), the ball 7 opens and the air and lubricating oil are metered and discharged through the orifice 11. However, in the present invention, it is also possible to omit the check spring. In that case, the check ball or plate moves up and down repeatedly in the check chamber due to the reciprocating movement of the adjuster of the present invention during operation, discharging air and lubricating oil little by little each time.

FIGS. 2 and 3 show second and third embodiments of the present invention, in which a check chamber 10 constituted by a cage 17 is provided outside the top plate 15, facing the ventilation hole 16 in the top plate 15. The check chamber has a check ball 7 (FIG. 2) or a check plate 18 (FIG. 3). Also, FIGS. 4A and 4B show two types of check plates 18,
Type A has smooth surfaces on both sides, and type B has a slit on one side to further promote air discharge and to more actively lubricate the contact surface between the adjuster star and the cam of the present invention.

The effects of the present invention are as follows.

(1) The air in the reservoir chamber is automatically released.

(2) Due to the effect of the check valve, air is not sucked from the orifice when starting the dry lash.

(3) Due to the effect of the check valve, lubricating oil accumulated in the reservoir chamber is unlikely to drain back when the machine is stopped.

(4) The lubricating oil discharged from the orifice has a positive effect on the lubrication of the contact surface between the cam and the bucket-type hydraulic latch adjuster.

(5) If a check spring is provided, by appropriately selecting the cracking pressure and orifice size, it will also serve as a relief valve, preventing pump-up of the cylinder in the bucket and preventing overlift of the engine valve. can.

[Brief explanation of drawings]

1, 2, and 3 are partial cross-sectional views showing first, second, and third embodiments of the present invention. Further, FIGS. 4A and 4B are a plan view and a sectional view showing the main parts. The symbols in the drawings indicate the following members, respectively. 1: cylinder head, 2: cam, 3: engine valve, 4:
bucket, 5: cylinder, 6: piston, 7: check ball, 8: check spring, 9: retainer, 10: check chamber, 11: orifice, 12: reservoir chamber, 13: reservoir chamber,
14: Hyperbaric chamber, 15: Top plate, 16: Ventilation hole, 1
7: Cage, 18: Check plate.

Claims (1)

[Scope of Claim for Utility Model Registration] 1. A check chamber that also serves as a ventilation hole communicating between the reservoir chamber of a bucket-type hydraulic latch adjuster and the outside air is provided on the top plate or is provided as a cage outside the top plate, and A bucket type hydraulic latch adjuster, characterized in that it has a check ball or a check plate in the check chamber for closing the reservoir chamber. 2. The bucket type hydraulic latch adjuster according to claim 1, wherein a check spring for pressing the check ball or the check plate is provided in the check chamber.