JPH0327726B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hydraulic latch adjuster used in a support portion of a rocker arm in a valve train of an internal combustion engine.

Conventionally, in an overhead valve type valve operating mechanism, a lash adjuster is used to automatically adjust the lash of the intake/exhaust valve and the rocker arm in a closed state to zero.

In the conventional latch adjuster, as shown in FIG. 1, the cage b holding the check ball a is separate from the plunger d, and
The cup is press-molded into a shape in which the peripheral edge of the cup is bent outward at a right angle, and the outer peripheral edge c of the cage b is fitted tightly into the bottom circumferential inner surface e of the plunger d.

In such a structure, if the interference between the inner circumferential surface e of the bottom part of the plunger and the outer circumferential edge e of the cage is small, the cage b will be hit hard from inside by the reciprocating check ball a, and will easily fall off. If the tightening margin is too large, when the cage b is fitted,
Since the cage b was plastically deformed beyond its elastic limit, an effective tightening margin could not be obtained and it was also likely to fall off.

Furthermore, there were some devices in which a circumferentially oriented groove was formed on the inner circumferential surface of the bottom of the plunger, and the outer circumferential edge of the cage was engaged with this groove. Similarly, it was not possible to deform the cage so as not to exceed the elastic limit and to engage the outer peripheral edge of the cage with the groove without play.

The present invention overcomes these drawbacks, and its object is to provide a hydraulic lash adjuster that allows a cage to be easily and securely attached to a plunger.

An embodiment of the present invention illustrated in FIGS. 2 to 4 will be described below.

1 is a hydraulic lash adjuster used in a four-stroke gasoline engine for motorcycles. Since the gasoline engine is small, the lash adjuster 1 itself is small, with a total length of approximately 30 mm and a diameter of approximately 10 mm. .

Further, the adjuster body 2 of the latch adjuster 1 has an open end 2a, and is adapted to be fitted into an adjuster insertion tube (not shown) so as to be freely retractable.

Furthermore, a plunger 3 is slidably fitted into the cylindrical adjuster body 2.

Furthermore, a retainer cap 4 is fitted onto the open end 2a of the adjuster body 2 to prevent the plunger 3 from protruding beyond a certain stroke.

In addition, at the center of the base 3a of the plunger 3,
A communication passage 3h that communicates a hollow cylindrical reservoir chamber 9 and a high pressure chamber 10, which will be described later, with each other is formed, and a valve seat 3b is formed at the opening of the communication passage 3h on the high pressure chamber 10 side. A circumferentially oriented locking groove 3d is formed in the inner surface 3c of the cylindrical portion of the base 3a, and the outer peripheral edge 7a of the check ball cage 7 housing the check ball 5 and the check ball spring 6 is engaged with the locking groove 3d. It is becoming more and more common.

The check ball cage 7 is formed by pressing a thin plate made of carbon tool steel or spring steel into a hat shape, and as shown in FIG. Four notches 7d are provided across the cage 7.
The center portion 7e of the cage 7 is recessed inward, and the center portion 7e of the cage 7 and the portion of the cylindrical portion 7c near the center portion 7e constitute the bottom of the cage 7, and the notch 7
Flange portion 7b and cylindrical portion 7c removed in step d
The remaining portion also constitutes an elastic locking portion of the cage 7.

Further, the depth x of the notch 7d is set to be as deep as the height of the cage 7, the raised height y of the cage center portion 7e is set high, and the upper width of the notch 7d is set to be as deep as the height of the cage 7. p and bottom width q are set wide.

Moreover, the thickness of the cage 7 is set to such a level that the deformation of the cage curved portion 7f that occurs when the cage outer peripheral edge 7a contacts the plunger bottom circumferential inner surface 3c does not exceed the plastic limit.

In the check ball cage 7, the check ball 5 is pressed against the valve seat 3b by the spring force of the check ball spring 6.

A high pressure chamber 10 is formed between the base 2b of the adjuster body 2 and the base 3a of the plunger 3, and within the high pressure chamber 10, a plunger spring 8 is interposed between the flange 7b of the check ball cage 7 and the base 2b of the adjuster body 2. ing.

Furthermore, a hollow cylindrical reservoir chamber 9 is formed in the plunger 3, and oil supply holes 2c and 3g are provided in the side walls of the adjuster body 2 and the plunger 3 so as to communicate with the reservoir chamber 9.

Furthermore, the outer end 3e of the plunger 3 is formed into a spherical shape, and the spherical outer end 3e is provided with an oil passage 3f communicating with the reservoir chamber 9.
A rocker arm (not shown) is swingably supported by the spherical outer end 3e.

Since the embodiment shown in FIGS. 2 to 4 is constructed as described above, the check ball 5 and the check ball spring 6 housed in the check ball 5 and the check ball spring 6, as shown by the two-dot chain line in FIG. The outer peripheral edge 7a of the cage 7 is connected to the plunger base 3a.
When the check ball cage 7 is pushed inward while in contact with the inner surface 3c of the cylindrical portion of the plunger 3, the curved portion 7f of the cage 7 deforms without causing plastic deformation, and the cage outer periphery 7a When the check ball cage 7 reaches the locking groove 3d, the elasticity of the cage 7 causes the check ball cage 7 to return to its original state as shown by the solid line, and the cage outer periphery 7
a engages with the locking groove 3d.

In this case, the material of the check ball cage 7 is carbon tool steel or spring steel, which is highly elastic, and the thickness of the cage 7 is thin, and the notch 7d is formed, so that the cage 7 does not undergo plastic deformation. ,
The cage outer peripheral edge 7a is pressed against the bottom surface of the locking groove 3d,
As a result, the check ball cage 7 is securely attached to the plunger 3 even if the cage 7 receives shocks and vibrations when the balls 5 come into contact with and separate from the valve seat 3b.

Also, the flange portion 7b of the check ball cage 7
is inclined diagonally downward, so simply by bringing the flange portion 7b into contact with the lower edge of the inner surface 3c of the cylindrical portion of the plunger base 3a and pushing the cage 7, the cylindrical portion 7c is deformed toward the center, and the outer circumference of the cage is Since the locking edge 7a can be slid upward while in contact with the inner surface 3c of the cylindrical portion of the plunger base 3a and reach the locking groove 3d, mounting of the check ball cage 7 is extremely easy.

In the embodiment shown in FIGS. 2 to 4, the outer end 3e of the plunger 3 is formed into a spherical shape and is used as a support for the rocker arm. However, as shown in FIG. The present invention can also be applied to a hydraulic lash adjuster 1 in which the base portion 2b is formed into a spherical shape and is used as a supporting portion of a rocker arm.

Further, in the above embodiments, a check ball spring is attached to each of the above embodiments, but the present invention can also be applied to a hydraulic latch adjuster without a check ball spring.

The present invention includes an adjuster body having an open end, a plunger slidably fitted to the inner peripheral surface of the adjuster body, and a high pressure partitioned by the adjuster body base and the plunger so as to bias the plunger in an extrusion direction. A plunger spring interposed in a chamber, a check ball installed on the high pressure chamber side so as to be able to open and close a communication passage communicating between the space inside the plunger and the high pressure chamber, and the check ball. In a hydraulic latch adjuster equipped with a check ball cage for holding, a locking groove for snapping the cage is provided at the base of the plunger, and a locking groove is provided at the base of the plunger, and a locking groove is provided from the bottom of the check ball cage toward the outer periphery of the cage. Since the elastic locking portion extending in the radial direction is formed, the elastic locking portion causes plastic deformation by simply inserting the tip of the elastic locking portion of the cage into the bottom of the adjuster and then pushing the cage. The cage can be firmly engaged with the groove at the bottom of the adjuster without causing any damage, and the cage can be reliably prevented from falling off.

[Brief explanation of drawings]

FIG. 1 is a vertical side view of the main part of a conventional hydraulic lash adjuster, FIG. 2 is a vertical side view of an embodiment of the hydraulic lash adjuster according to the present invention, and FIG. 3 is a main part thereof. FIG. 4 is a perspective view of the cage in the same embodiment, and FIG. 5 is a longitudinal side view of another embodiment. 1... Hydraulic latch adjuster, 2... Adjuster body, 3... Plunger, 4... Retainer cap, 5... Check ball, 6... Check ball spring, 7... Check ball cage, 8... Plunger. Spring, 9...reservoir chamber, 10...high pressure chamber.

Claims (1)

[Claims] 1. An adjuster body having an open end, a plunger slidably fitted to the inner circumferential surface of the adjuster body, and a high-pressure chamber defined by the adjuster body base and the plunger so as to bias the plunger in the extrusion direction. a plunger spring installed in the high pressure chamber; a check ball installed on the high pressure chamber side so as to be able to open and close a communicating path communicating between the space inside the plunger and the high pressure chamber; and a check ball for holding the check ball. In the hydraulic latch adjuster equipped with a ball cage, a locking groove for snapping the cage is provided at the base of the plunger, and the locking groove extends radially from the bottom of the check ball cage toward the outer periphery of the cage. A hydraulic latch adjuster characterized by forming an extended elastic locking part.