JPH0447365Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention is a hydraulic lash adjuster that automatically corrects the valve gap in a valve train of an internal combustion engine using hydraulic pressure and the elastic force of an elastic member, especially for a high-speed rotation type internal combustion engine. This invention relates to an improvement of a check valve cage in a hydraulic lash adjuster useful for.

In the conventional free-ball type latch adjuster, as shown in A and B in FIG. This is a mechanism that automatically opens and closes the check valve 6. For this reason, when the internal combustion engine is rotating at high speed, in order to quickly close the check valve 6 after it opens, the check valve 6 must move as quickly as possible over a distance as small as possible on the central axis of the check valve cage 5. is required. but,
The check valve 6 may move laterally as shown by the dotted line in FIG. 1B. In this state, the amount of movement of the check valve 6 increases, the oil flow force does not act uniformly, and the closing time of the check valve 6 becomes longer. The function will not be able to sufficiently follow the rotational speed. Therefore, in order to reduce the amount of movement of the check valve 6 in the horizontal and vertical directions, it is necessary to keep the gap between the check valve 6 and the inner diameter of the check valve cage 5 and the amount of movement of the check valve 6 with high accuracy. However, it had the disadvantage that it was difficult to obtain good operation in the high-speed rotation range. Furthermore, in a hydraulic lock adjuster used in a high speed internal combustion engine, the bottom portion 5b of the check valve cage is violently struck by the check valve 6, causing the bottom portion to undergo warp deformation. This is because the check valve cage 5 is a press-molded product of a steel plate, so it is not easy to add weight to areas where strength is required. Further, due to this deformation, the amount of movement of the check valve 6 increases, and there have been cases where the check valve 6 cannot sufficiently follow the flow of oil during high speed rotation.

In view of the above points, the present invention simplifies the machining process, widens the dimensional tolerance range of the product, improves productivity, and improves the followability of the valve gap correction function in the high-speed rotation range. The purpose is to provide a valve cage for a hydraulic lash adjuster that is of good quality and has great durability.

In order to achieve the above object, the present invention is characterized by combining the following features with the check valve cage.

Highly elastic synthetic resin should be used as the cage material.

A plurality of holes communicating from the bottom of the cage to the check valve side are provided axially symmetrically with respect to the axial center.

The bottom and side walls of the cage are thicker.

A radial groove is provided on the top surface of the flange portion of the cage.

Embodiments of the present invention will be described below with reference to FIG. 2 and FIGS. 3A and 3B. Reference numeral 1 designates a hydraulic latch adjuster for a high-speed rotating internal combustion engine, and its body 2 is a cylindrical body having an open end 2a. The plunger 3 is slidably fitted into the body 2, and a retainer cap 4 is attached to the open end 2a to prevent the plunger from protruding beyond a certain length. A check valve seat 3a is provided at one end of the plunger 3, and a check valve cage 5 made of synthetic resin is mounted therein, and a check valve 6 is accommodated in this cage. A plunger spring 7 is housed between the check valve cage 5 in the hydraulic chamber 9 and the bottom 2b of the body 2, and a plunger spring 7 is housed between the check valve cage 5 in the hydraulic chamber 9 and the bottom 2b of the body 2.
pushing in the direction of A hollow cylindrical reservoir chamber 8 is formed in the plunger 3, and oil supply holes 2c and 3c are provided in the side walls of the body 2 and the plunger 3, respectively, so as to communicate with the reservoir chamber 8. One end of the plunger 3 has a spherical outer end 3b having an oil passage 3d communicating with the reservoir chamber 8.
is formed so as to come into contact with the rocker arm 10. Engine oil is supplied to the reservoir chamber 8 through an engine-side oil passage (not shown) and the oil supply holes 2c and 3c. Reservoir chamber 8
When the check valve 6 is opened, the oil in the
e, to the hydraulic chamber 9 of the body 2 through the gap between the check valve seat 3a and the outer periphery of the check valve 6;
The oil is also sent to the gap between the rocker arm 10 and the spherical outer end 3b of the plunger 3 via the oil passage 3d. If a gap occurs between the rocker arm 10 and the intake/exhaust valve 12 or the cam 11, the plunger 3 is pushed up by the elastic force of the plunger spring 7 to correct the gap. At this time, the pressure in the hydraulic chamber 9 decreases, and the check valve 6 opens away from the check valve seat 3a, so that the oil in the reservoir chamber 8 is supplied into the hydraulic chamber 9 through the oil hole 3e. The inside is filled with oil.
Next, when the cam 11 is lifted and the rocker arm 10 is pressed, the plunger 3 is pushed down and the check ball 6 is pressed against the check valve seat 3a.
The oil in the hydraulic chamber 9 is pressurized and the body 2 is seated on the body 2.
It leaks from the small gap between the inner diameter and the outer diameter of plunger 3. Further, this oil returns into the reservoir chamber 8 through the oil supply hole 3c. Plunger 3 like this
By reciprocating, the fulcrum of the rocker arm is changed, so the valve train is always maintained at zero lash.

Next, the structure and operation effects of the present invention applied to the hydraulic lash adjuster shown in FIG. 2 will be explained.The present invention has the following four characteristics.

The check valve cage 5 is made of synthetic resin with excellent elasticity. That is, as shown in the tensile stress-tensile elongation diagram in Fig. 4, the conventional press-formed steel plate b has extremely poor elasticity, but the synthetic resin shown by the diagonal line a has high elasticity and can absorb high impact energy. It has an effect (buffering effect),
By thickly reinforcing thin-walled parts, durability can be improved when used at high speed rotation. Furthermore, it has better formability than conventional press working of steel plates, and the shapes described below can be easily obtained.

Several holes 5c as shown in FIG. 3 are provided in the bottom 5b of the check valve cage 5 in an axially symmetrical manner with respect to the central axis. As a result, the flow of oil pushes up the check valve 6 from below, so that the check valve 6 is easily seated on the check valve seat 3a, which is the direction of oil flow, and the followability of the check valve 6 at high speeds is improved. That is, the plunger sinking amount vs. check valve movement diagram in FIG. 5 is for A for the check valve cage of the present invention shown in FIG. 2, and B for the conventional check valve cage shown in FIG. 1. shows the relationship between the initial sinking amount of the plunger 3 and the amount of movement of the check valve 6 until the check valve 6 lands on the check valve seat 3a when a load is applied to the plunger head 3b. As an example, when comparing the shape of the check valve cage of the present invention with the conventional type, it can be seen that the conformability is improved by approximately 20%.

The volume of the hydraulic chamber 9 is reduced by thickening the bottom portion 5b or other portions of the check valve cage 5. In the synthetic resin check valve cage described above, the life of the cage itself can be extended by increasing the wall thickness in the desired areas, but it is also possible to reduce the volume of the hydraulic chamber and reduce the total amount of air bubbles and oil in the hydraulic chamber. As a result, the spring constant of the entire valve train is increased, resulting in a hydraulic lash adjuster that operates well at high rotations and high loads. be able to.

In addition to the above, in order to reduce the volume of the hydraulic chamber 9, it is also effective to make the bottom portion 2b of the cylindrical body 2 shallow within a size range smaller than the stroke of the plunger spring 7.

A radial groove 5d is formed in the flange portion of the check valve cage 5. This can reduce the amount of sinking of the plunger by eliminating air bubbles that accumulate in the upper part of the hydraulic chamber when the internal combustion engine is stopped or during operation, together with the flow of oil.

Incidentally, these various improvements can also be applied to hydraulic lash adjusters having check valves other than the embodiment shown in FIG.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view showing the main part of the conventional example, Fig. 2 is a cross-sectional view showing an example of the implementation of the present invention, Fig. 3 is a cross-sectional view of the main part, and Fig. 4 is the tensile stress-tension of the material. The elongation diagram, FIG. 5, is a diagram showing the amount of plunger sinking versus the amount of check valve movement. The symbols in the drawings indicate the following members, respectively. 1... Latch adjuster, 2... Body, 3... Plunger, 4... Retainer cap, 5... Check valve cage, 6... Check valve, 7... Plunger spring, 8... Reservoir chamber, 9 ...Hydraulic chamber, 10...Rotzker arm, 11...Cam,
12...Intake and exhaust valve.

Claims (1)

[Scope of utility model registration request] a cylindrical body having an open end; a plunger slidably fitted to the inner peripheral surface of the body and abutting a part of the rocker arm at its upper end; A plunger spring installed in a hydraulic chamber defined by a plunger, a check valve that opens and closes an oil hole that communicates a reservoir chamber in the plunger with the hydraulic chamber, and a check valve cage that houses the check valve. In the check valve cage, a plurality of holes communicating from the bottom of the check valve cage to the check valve side are provided, and the holes are arranged axially symmetrically with respect to the central axis of the check valve cage, and A hydraulic latch adjuster characterized in that a highly elastic synthetic resin is used as the material of the check valve cage, the bottom and side walls of the check valve cage are made thicker, and radial grooves are provided on the upper surface of the flange part. Star.