JPH0329527Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a hydraulic tappet structure, and in particular, to a hydraulic tappet structure that is equipped with an intake/exhaust valve stop function and is used in a variable cylinder engine to ensure exhaust braking force. This invention relates to a hydraulic tappet structure that allows for good assembly workability.

[Conventional technology]

Hydraulic tappets are generally employed to compensate for changes in tappet clearance due to the effects of wear and thermal expansion in valve train mechanisms (e.g.,
58-88412).

By the way, the applicant of the present application has improved this hydraulic tappet and proposed a hydraulic tappet that functions as a valve stop mechanism to eliminate pumping loss in a variable cylinder engine.

Here, in the structure of the above proposal, as shown in Fig. 4, a support c is slidably provided in a cylindrical sleeve b fixed to a fixed system a such as a cylinder head, and a support c is provided inside the support c. A plunger e, which forms a hydraulic chamber d, is slidably provided. Further, the support c is pressed downward by a spring f provided between the support c and the sleeve b, and supports the rocker arm g in a floating manner over the push rod h and the valve stem i.

[Problem that the invention attempts to solve]

By the way, the butterfly valve k installed in the exhaust pipe j
When a hydraulic tappet constructed as described above is employed in an internal combustion engine that obtains an exhaust braking force, the set force of the valve spring l is substantially reduced by the elastic force of the spring f. As a result, there was a risk that the exhaust valve m would be easily opened due to the exhaust pipe internal pressure p, resulting in a problem that a sufficient exhaust braking force could not be secured. On the other hand, increasing the set force of the valve spring l will impede the strength and valve operating characteristics. Further, a decrease in the set force of the valve spring 1 has the disadvantage of making the valve train more likely to bounce.

[Purpose of invention]

The present invention was devised in view of the above-mentioned problems, and its purpose is to create a hydraulic tappet with good assembly workability that can ensure exhaust braking force in a hydraulic tappet structure with a valve stop function for a variable cylinder engine. It is there to provide structure.

[Summary of the idea]

The present invention includes a fixed system, a support that is movable up and down on the fixed system and supports the rocker arm in a floating manner, and a spring that selectively engages either the fixed system or the support according to the movement of the support. The main feature is that a seat is provided, a spring is provided between the spring seat and a seat formed on the support, and the spring is made to spring when the spring seat is engaged with a fixed system. .

〔Example〕

A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

As shown in FIG. 1, a fixed system 1 such as a cylinder head is formed with a concave portion 3 that opens toward the valve mechanism side such as a push rod 2 below.
A sleeve 4 is press-fitted into this concave portion 3.
A support 6 is slidably provided within the sleeve 4 for floatingly supporting the rocker arm 5 on the push rod 2 or the like. This support 6 has a cylindrical upper part that is inserted into the sleeve 4 and forms a hydraulic chamber 8 between it and the plunger 7, and a support part 6a that rotatably supports the rock shaft 9 is formed in the lower part. be done. A cylindrical plunger 7 is slidably provided inside the support 6, and a spring 1 is interposed between the support 6 and the support 6.
0 and is pressed toward the upper end of the sleeve 4.

By the way, between the fixed system 1 and the support 6, there is a rocker arm 5 which is swung around the upper end of the valve stem 13 as a fulcrum by the upward force of the cam when the check ball 12 is pushed down by the electromagnetic solenoid 11 to stop the valve. A spring 14 is provided for resiliently returning the push rod 2 to the push rod 2 side to firmly move the push rod 2. If the elastic force of the spring 14 affects the valve spring 15, its set force will be reduced, which is undesirable.

In the present invention, an annular engaging step portion 6b is formed on the circumferential side of the support 6 below the sleeve 4 by reducing the diameter in different steps, and the engagement step portion 6b extends outward in the radial direction of the support 6. A ring-shaped spring seat 16 is detachably provided so as to face the sleeve 4 constituting the fixing system from the moving direction of the support 6. This spring seat 16 is configured such that its outer edge engages with the sleeve 4 as the rocker arm 5 and support 6 rise due to a cam lift, and its inner edge separates from the engaging stepped portion 6b of the support 6. On the other hand, when the push rod 2 is located on the base circle of the cam, the spring seat 16
is detached from the sleeve 4 and engaged with the engagement step 6b of the support 6, and a considerable gap S is created between the spring seat 16 and the sleeve 4.
is beginning to form. On the other hand, on the support part 6a side of the support 6, there is an annular seat part 6c which is made to face the spring seat 16 and whose diameter is reduced in different steps.
is formed. A spring 14 is interposed between the seat portion 6c and the spring seat 16.

And the spring 14 is a spring seat 16
When the locking arm 5 is engaged with the engagement stepped portion 6b of the support 6, the locking arm 5 is integrated with the support 6 itself.
When the spring seat 16 is engaged with the sleeve 4, a reaction force is applied to the fixing system 1, and the support 6 is elastically returned downward.

In the present invention constructed as described above, when the exhaust brake is applied and the push rod 2 is positioned on the base circle of the cam and the valve is opened, the spring 14 is integrated with the support 6, and the valve is closed. A predetermined exhaust braking force can be obtained without reducing the set force of the spring 15.

Furthermore, even during normal valve operation, the spring 14 can be prevented from engaging as much as possible in reducing the biasing force of the valve spring 15, and the occurrence of valve bounce can be prevented.

Furthermore, the gap S formed between the spring seat 16 and the sleeve 4 described above corresponds to the stroke in which the support 6 can freely rise and fall, that is, the rocker arm 5
This gap S corresponds to the valve gap required between the adjuster screw and the valve stem 13, and this gap S can be adjusted appropriately like a conventional valve seat by inserting a thickness gauge between the adjuster screw and the end of the valve shaft. This allows the valve gap to be adjusted at will, thereby improving assembly work efficiency.

In FIGS. 2 and 3, the support 6, plunger 7, spring 14, etc. that are about to fall are fixed to the fixing system 1 when the rocker arm is supported by a push rod or the like because it is slidable relative to the sleeve 4.
An embodiment is shown that includes drop-off prevention means for holding the device in place.

In the device shown in FIG. 2, a ring-shaped engagement claw member 17 is provided at the open end of the concave portion 3, and a spring seat 16 is engaged with the ring-shaped engagement claw member 17 to prevent it from falling.

What is shown in FIG. 3 is a through hole 18 that passes through a fixing system 1 such as a cylinder head and communicates with a concave portion 3.
The support 6 and the like are held in the fixing system 1 by inserting a bolt 19 through the plunger 7 and screwing it into a female thread 20 formed on the inner periphery of the plunger 7.

In either case, the basic structure is the same as that of the above embodiment, and the ease of assembly is further improved by preventing falling.

[Effect of idea]

In summary, the present invention provides the following excellent effects.

(1) Since the spring is integrated with the support when the valve is closed when the push rod is positioned on the base circle of the cam, it is possible to prevent the elastic force of the spring from acting on the valve spring when the exhaust brake is activated. , the exhaust braking force can be secured.

(2) Also, since the spring elastic force is cut off from the valve spring, bouncing can be controlled when the valve is operated.

(3) On the other hand, when the valve is stopped, the spring seat is engaged with the fixed system by raising the support, and elastic force for the support return operation by the spring can be obtained.

(4) The gap formed between the spring seat and the sleeve can be adjusted by inserting a thickness gauge between the adjuster screw and the end of the valve shaft in the same way as with conventional valve seats. Yes, it can improve assembly work efficiency.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view showing a preferred embodiment of the present invention, FIGS. 2 and 3 are side sectional views showing other embodiments, and FIG. 4 is a side sectional view showing a conventional example. In the figure, 1 is a fixed system, 5 is a rocker arm, 6 is a support, 6c is a seat, 14 is a spring, and 16 is a spring seat.

Claims (1)

[Scope of utility model registration request] A support that is movably movable up and down on the fixed system and supports the rocker arm in a floating manner, and a support that is detachably provided on the support so as to face the fixed system from the direction of movement, and is engaged with the fixed system and detached from the support. A hydraulic tappet structure comprising a spring seat and a spring provided between the seat and the support and springing when the seat is engaged with the fixing system.