JPH0413367Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention relates to a hydraulic tappet structure, and in particular, to improve assembly workability in a hydraulic tappet structure equipped with an intake/exhaust valve stop function and used in a variable cylinder engine. Concerning a simple hydraulic tappet structure that can be improved.

BACKGROUND OF THE INVENTION Hydraulic tappets are commonly employed to compensate for changes in tappet clearance due to the effects of wear and thermal expansion in valve train mechanisms.

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

If the above-mentioned hydraulic tappet is used in an internal combustion engine that obtains exhaust braking force from a butterfly valve k installed in the exhaust pipe j, then if the exhaust valve m has an internal pressure p of the exhaust pipe
3, the movable support c is pulled down by the spring f with respect to the fixed system a, and hydraulic oil is introduced into the oil chamber d, which then closes the exhaust valve. There is a risk that it may not be closed. Therefore, as shown in the figure, the support c is provided with a snap ring n that engages with the plunger e in order to restrict its downward movement, and the new installation of this snap ring n necessitates valve cap adjustment.

[Problems to be Solved by the Invention] Conventionally, the support c was engaged with the plunger e, which moves together with the support c and wears out as it comes into contact with the sleeve b, through a snap spring n. There was a risk that the position of support c would change due to wear, causing the valve gap to fluctuate.

Further, the support c and the plunger e are movable relative to the sleeve b fixed to the fixed system a,
Since these supports c and the like are supported only after the rocker arm g is placed on the push rod h and the like, they fall off from the sleeve b during assembly, resulting in poor assembly performance.

In addition, as a structure that simply restricts falling off, the JP-A-58
Although this is disclosed in Japanese Patent No. 91316, there is a problem in that it cannot contribute to the position of the rocker arm, that is, to adjust the valve gap.

[Purpose of the invention] The present invention was devised in view of the above-mentioned problems, and its purpose is to improve assembly workability such as valve gap adjustment in a hydraulic tappet with a valve stop function for a variable cylinder engine. To provide a hydraulic tappet structure which can be appropriately adopted even in an engine equipped with an exhaust brake device.

[Summary of the invention] The invention grips a rocker shaft of a rocker arm whose upper part is guided along a guide surface formed on a fixed system, and whose lower part is elastically biased from the fixed system and swings up and down by a cam lift. a support for floatingly supporting the rock shaft; and a regulating means for engaging the upper part of the support with an engaging portion formed on the guide surface to restrict the downward movement of the rock shaft including the support. It is.

[Embodiment] A preferred embodiment of the present invention will be described below in detail 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 provided within the sleeve 4 so as to be movable up and down, using the inner peripheral wall as a guide surface 4a for floatingly supporting the rocker arm 5 on the push rod 2 or the like. This support 6 has an upper part inserted into the sleeve 4 formed on a cylindrical body to form a hydraulic chamber 8 between it and the plunger 7, and a lower part formed with a grip part 6a for rotatably gripping the rock shaft 9. be done. A cylindrical plunger 7 is slidably provided inside the support 6, and is urged toward the upper end of the sleeve 4 by a spring 10 interposed between the plunger 7 and the support 6.

Incidentally, 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, the guide surface 4a of the sleeve 4, which constitutes a fixed system for guiding the vertical movement of the support 6, is cut into an annular shape so as to expand in diameter in different steps at the upper part thereof, thereby forming an engaging portion 4b. It is formed. On the other hand, on the upper part of the support 6, there is a flange-shaped regulating means 16 that engages along the engagement portion 4b formed on the guide surface 4a.
will be provided. This restricting means 16 engages with the engaging portion 4b to restrict the downward movement of the rocker shaft 9 including the support 6.

The downward movement restriction position of the support 6 is set to correspond to the position of the rocker shaft 9 during normal valve operation. Further, the spring 14, which functions when the valve is stopped, is configured so that it does not overlap the valve spring 15 due to the position restriction of the support 6, and does not reduce its set force.

In addition, in this embodiment, the snap spring n (Fig. 3), which was conventionally locked to both the sleeve b and the support c and attached one end of the spring f, is eliminated, and the spring is inserted into the groove 4c recessed in the sleeve 4. Since the guide surface 4a is locked, the guide surface 4a can be set long, and the vertical movement of the support 6 can be guided over a long distance, thereby improving its durability.

In the present invention configured as described above, the downward movement of the support 6 is restricted by the restriction means 16, and the rock shaft 9 can be floatingly supported in the normal position while the elastic force of the spring 14 is canceled. can. Therefore, appropriate valve gap adjustment can be easily performed based on the support position of the rocker shaft 9.

Furthermore, since the support 6, which can be raised and lowered by the sleeve 4 constituting the fixing system 1, can be supported by the engaging portion 4a and the regulating means 16, it is possible to prevent the support 6 from falling off. The sleeve 4 has a structure in which the cylindrical body part 4d and the upper end lid part 4e are divided, so that the support 6 can be easily installed inside the sleeve 4.

In addition, the downward movement of support 6 is restricted by plunger 7.
Since the configuration is such that the support 6 is moved to the sleeve 4, the appropriate position of the support 6 can be ensured regardless of changes in the tappet clearance due to wear of the plunger 7.

Furthermore, although the hydraulic tappet of the present invention is used in a variable cylinder engine, it is possible to provide a predetermined valve gap during normal valve operation, thereby eliminating the influence of the spring 14 on the valve spring 15 during exhaust brake operation. of exhaust braking force can be obtained.

A modified embodiment is shown in FIG.

In this embodiment, instead of integrally forming the restricting means 16 at the upper end of the support 6, a removable snap ring is used to engage the engaging portion 4b. The other configurations are the same as those of the above embodiment.

[Effects of the Invention] In summary, the present invention provides the following excellent effects.

(1) By restricting the downward movement of the rocker shaft including the support with the regulating means, the rocker arm can be floatingly supported in a predetermined position while canceling the elastic force of the spring, and the valve gear can be adjusted appropriately based on that position. can be easily applied.

(2) As a result of being able to restrict the downward movement of the support in the fixed sleeve by the restriction means, it is possible to prevent the support from falling off and improve the assembly work efficiency.

(3) By placing the sleeve in charge of regulating the downward movement of the support, the effects of wear on the plunger can be avoided and the rocker arm can be supported in an appropriate position.

(4) When used in a variable cylinder engine, since an appropriate valve gap can be given, the influence of the spring on the valve spring when the exhaust brake is activated can be eliminated, and a considerable exhaust braking force can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view showing a preferred embodiment of the present invention, FIG. 2 is a side sectional view showing a modified embodiment, and FIG. 3 is a side sectional view showing a conventional example. In the figure, 1 is a fixing system, 4a is a guide surface, 4b is an engaging portion, 5 is a rocker arm, 6 is a support, and 16 is a regulating means.

Claims (1)

[Scope of utility model registration request] The upper part is guided along a guide surface formed on the fixed system, and the lower part is resiliently biased from the fixed system, and the rocker shaft of the rocker arm, which swings up and down by a cam lift, is grasped and floating supported. A hydraulic tappet structure comprising: a support; and a regulating means for engaging an upper part of the support with an engaging portion formed on the guide surface to regulate the downward movement of the rocker shaft including the support.