JPS60206914A - Automatic correction device for valve gap of hydraulic valve - Google Patents

Abstract

PURPOSE:To enhance the dynamic characteristic and reduce the manufacturing cost by fitting a plunger slidably in the body of a bottomed cylinder having an oil hole at its top bottom, and by installing a check valve in the high pressure chamber partitioned in the body through said operation. CONSTITUTION:This hydraulic lash adjuster 7 includes a closed end 71a having an oil hole 75 at the top and a body 71 consisting of a bottomed hollow cylinder having an open end 71b in the lower part, and a plunger 72 is inserted in said hollow part. Thus a high pressure chamber 73 is formed between said closed end 71a of the body 71 and the plunger 72, and the chamber 73 accommodates a resilient member 74 to energize the plunger outward. Also in said high pressure chamber 73 a check valve 76 to open and close the abovementioned oil hole 75 is installed being retained in a cage 77. The adjuster 7 is fitted in a supporting hole 11 which is formed in a locker arm 1 and in communication with an oil sump 10 so as to function as automatic corrector for the valve gap.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hydraulic valve gap automatic correction device for automatically correcting a valve gap using hydraulic pressure and elastic force of an elastic member in a valve train for an internal combustion engine. As is well known, there are two types of rocker arm pivot systems in valve train mechanisms: a center pivot system and an engine 1-pivot 1 one-way system, and although hydraulic lash adjusters have been effectively used for both pivot systems, Deterioration in functionality due to wear has long been a problem. In addition, the current situation is that we have no choice but to take measures that go against the weight reduction of valve mechanisms, such as adding parts to counteract this.

The present invention aims to solve these problems, and will be described below with reference to the drawings, taking the center pivot method as an example. FIG. 1 shows a conventional example of a valve train having an automatic valve gap correction device, in which 1 is a rocker arm, 2 is a valve, 3 is a valve spring, 4 is a cam, and 5 is a rocker shaft.
6 is a hydraulic lash adjuster. Figure 2 shows the details of the hydraulic lash adjuster 6, and the body 61 is shown in Figure 2.
It is a bottomed hollow cylindrical body having an open end 61a in two parts and a closed end 61b in the lower part, a hollow plunger 62 is fitted in the hollow part, and has a part 62a extending outward from the hollow plunger 62. A high pressure chamber 63 is formed between the closed end 61a of the body 61 and the plunger 62, and an elastic body 64 is located within the hydraulic chamber 63 to urge the plunger 62 outward from the body 61. . Also, the open end 6 of the plunger 62
Oil is led from the outside of 2a to an oil reservoir chamber 65 within the plunger 62. Further, a check valve 67 that controls opening and closing of an oil hole 66 between the oil reservoir chamber 65 and the high pressure chamber 63, and a check valve cage 68 that holds the check valve are provided in the high pressure chamber 63. As shown in FIG. 1, the hydraulic lash adjuster 6 is connected to the support hole 11 of the rocker arm 1
The plunger opening end 62a is disposed toward the bottom side of the support hole 11, and the closed end 61b of the body 61 is disposed toward the open side of the support hole 11.

When cam 4 rotates due to engine reversal, rocker arm 1
is swung around the rocker shaft 5 in accordance with the cam 4, and the valve 2 is opened and closed via the hydraulic lash adjuster 6. When the repulsive force of the valve opening oil well spring 3 is applied to the hydraulic lash adjuster 6, the force of the valve spring 3, which is much stronger than the force of the elastic body 64, overcomes the resistance force of the elastic body 64, causing the plunger 62 to contract into the body 61. However, since the high pressure chamber 63 slides in a direction to decrease its volume, the pressure inside the high pressure chamber 63 increases and the oil flows back into the oil reservoir chamber 65 through the oil hole 66 . As a result, the check valve 67 is pressed against the check valve seat 66a and closes the oil hole 6G, and the high pressure chamber 63
The oil inside is under high pressure and reaches the rigid IIM, so during the valve opening period, as the cam 4 rotates, the plunger 6
2 moves with respect to the body 61 &(Q in a static state almost integrally with the body 61. During this time, the oil in the high pressure chamber flows through the slight gap between the circumferential surface of the body 61 and the outer circumferential surface of the plunger 62. The plunger 62 only exhibits a slight retraction movement within the body 61.

When the rotation of the cam 4 further progresses and the contact surface 1c of the rocker arm 1 with the cam 4 reaches the base edge 4a of the cam 4, the valve 2 is seated and the force acting on the body 61 of the valve spring 3 disappears. The hydraulic lash adjuster 6, which was in a contracted state due to the force of the valve spring 3 generated in the valve, expands and corrects the gap in the valve mechanism caused by thermal deformation etc. until it becomes zero. .

In general, hydraulic lash adjusters have a technical requirement to make the oil reservoir chamber inside the plunger as large as possible to prevent oil volume shortages, while at the same time reducing the overall weight as much as possible to maintain good dynamic characteristics. Such a disadvantage 711 has occurred in the configuration.

(1) Since the annular plane portion 62b serving as the pressure receiving surface of the plunger opening end 62a shown in FIG. 2 has a small area, the contact surface pressure with the rocker arm 1 is high and it is likely to become sagging during operation. This tendency is particularly noticeable when the rocker arm is made of a soft material such as a light alloy. In order to eliminate this drawback, an intermediate body such as a spacer 12 that increases the contact area may be provided between the plunger opening end 62a and the contact surface 1a of the Nittsuka arm to reduce the surface pressure, or the spacer 12 may be quenched and hardened. Countermeasures have been taken, but in either case, the inertial weight of the valve train increases, creating a problem that hinders the path to technological improvement of improving dynamic characteristics by reducing the weight of the valve train, and further increases manufacturing costs. Problems will also arise.

(2) Side l of support hole 1 of body 61 and rocker arm 1
Since the side wall 11b is always in a relative movement relationship, sliding always occurs between the two in the fitted state, resulting in wear on the side wall 1b. This tendency is strong when the product is made of light alloy, etc., and as the wear progresses, the hydraulic lash adjuster 6 swings in the support hole 11 due to the play between the two, causing the plunger 62 to move. The support hole 11
The wear of the abutting portion of the support hole 11 itself is further accelerated, and the safety of the operation of the valve train is compromised. In order to eliminate this drawback, it is necessary to use a quench-hardened steel material for the side wall 1b, which results in the same problem as described in the previous section (1).

(3) In order for the body 61 to move smoothly relative to the rocker arm support hole 11, a step is required to finish the inner surface of the support hole 11 into a sufficiently smooth surface in order to keep sliding resistance low. .

In view of the above points, the present invention aims to solve the problems related to the surface pressure at the opening end of the plunger and the outer circumference of the body and the lash adjuster support hole, which could not be avoided with the conventional configuration. It provides a lash adjuster.

FIG. 3 shows an example of the present invention. The body 71 of the hydraulic lash adjuster 7 is a hollow cylindrical body with a bottom and a closed end 71a at the upper part and an open end 71b at the lower part. It has a portion 72a that is fitted and extends outwardly therefrom.

The high pressure chamber 73 is connected to the closed end 71a of the body 71 and the plunger 7.
2, the elastic body 74 is located within the high pressure chamber 7:3 and urges the plunger 72 outward from the body 71. (Body closed); (The end 71.a is provided with an oil hole 75 for introducing oil from the outside. Also, a check valve 76 and a check valve cage 77 that control opening and closing of the hole 75 are installed in the high pressure chamber. The hydraulic lash adjuster according to the present invention is characterized in that the oil reservoir chamber is separated, and as shown in FIG. 4 (second implementation example), the oil reservoir chamber 8 is provided separately to As shown in Fig. 5, the combination pair introduced with lash adjuster 7 is
Alternatively, an oil reservoir chamber 10 may be further provided in the support hole 11 as shown in FIG. In this case, unlike conventional hydraulic lash adjusters, the closed end 71a of the body 7 is located on the bottom side of the support hole 1F. 7, the plunger opening end 71a is arranged to face the opening side of the support hole 11. FIG. Figure 8 shows how it is assembled into a rocker arm.

According to the structure of the present invention, when the cam 4 rotates due to the reverse rotation of the engine, the rocker arm 1 swings according to the cam 4, and the valve 2 is opened and closed via the hydraulic lash adjuster 7.

When the repulsive force of the valve opening oil well spring 3 is applied to the hydraulic lash shaft stiff, the valve spring 3 becomes much stronger than the force of the elastic body 74.
The force overcomes the resistance force of the elastic body 74 and the plunger 72
The oil contracts in the body 71 and slides in a direction to reduce the volume of the high pressure chamber 73, so that the pressure inside the high pressure chamber 73 increases and the oil flows back into the oil reservoir chamber 8 through the oil hole 75.

As a result, the check valve 76 is connected to the check valve seat 7.
6a closes the oil hole 75, and the oil in the high pressure chamber 73 has a high pressure and reaches a state close to a rigid body. Therefore, during the valve opening period, as the rotation of the cam 4 progresses, the plunger 72 closes the oil hole 75.
1 and moves almost integrally with the body 1 in a quasi-static state. During this time, the oil in the high pressure chamber flows out through a small gap between the circumferential surface of the front body 71 and the outer circumferential surface of the plunger 72, and the plunger 72 only slightly contracts and moves inside the body 71. It is. The rotation of the cam 4 further progresses, and the contact surface IC2 of the rocker arm 1 with the cam 4 contacts the cam 4.
When reaching the base circle 4a, the valve 2 is seated and the force of the valve spring 3 on the body 71 disappears. At this time, the hydraulic lash adjuster 7, which was in a contracted state due to the force of the valve spring 3 generated during the valve opening, expands and compensates for the gap in the valve mechanism caused by thermal deformation etc. until it becomes zero. do.

The effects obtained by the present invention are as follows.

(1) As is clear from the illustrated configuration, since the body 71 moves together with the support hole 11, no sliding occurs between the body 71 and the support hole 11.

In addition, since the contact surface of the lash assia stiff with the rocker arm 1 is the closed end 71a of the body 71, its pressure receiving area is much larger than that of the plunger open end in the case of a conventional lash adjuster, so the surface pressure can be kept low. As a result, the wear of the lash adjuster 7 and the support hole 11 can be suppressed to a much lower level compared to the conventional example. The various measures required in the conventional example are no longer required.With this solution, the valve train mechanism can ensure the safe operation of the lash adjuster and also achieve a weight reduction that could not be achieved in the past, resulting in improved dynamic characteristics and manufacturing efficiency. This can bring about a new effect of reducing costs.

(2) Furthermore, since there is no sliding movement between the body 71 and the support hole 11 as described in the conventional example, the body 71 can be lightly press-fitted into the support hole 11 without deforming the body 71. This also overcomes the drawback of the lash adjuster falling off from the support hole, which occurred in the device, and has the effect of reducing troubles during the engine assembly process.

[Brief explanation of drawings]

FIG. 1 is an overall explanatory diagram showing a conventional example, and FIG. 2 is a sectional view of the main parts. Figures 3.4.7 and 5.6.8 are cross-sectional views of essential parts showing examples 1.2.3 of implementation of the present invention, respectively, and Figure 5.6.8.
The figure is an overall explanatory diagram of them. The symbols in the diagram indicate the following parts 61: Rocker arm 2: Valve 3: Valve spring 4: Cam 5: Rocker shaft 6: Hydraulic lash adjuster 7: Hydraulic lash adjuster 8: Oil sump chamber 9: Integral structure Body lO: Oil sump chamber 11: Support hole 12: Spacer lance 1 Fig. lance 3gJ lance 5 figure yf7 figure Procedural amendment May 1980 lO Commissioner of the Japan Patent Office Kazuo Wakasugi], Indication of case 1982 Patent Application No. 62174 No. 2, Title of the invention: Hydraulic valve gap automatic correction device 3, Relationship with the case of the person making the amendment: Patent applicant: 4, Attorney: 6 Number of inventions increased by the amendment: None 7, Specification subject to amendment: 8, Contents of the amendment Contents of the amendment in the appendix The points in the law in the specification of the present application are amended. 1. In the second line of page 5, the word "reversing" should be corrected to "driving". 2. In the 3rd line of page 6, replace "basic edge" with "basic circle"
and corrected one character. 3. In line 5 of page 6, correct one character from ``The valve is open at this time'' to ``The valve is open at this time.'' 4. On page 9, line 12, correct one character from "bonding pair" to "combinant." j, on page 10, in the 6th line, the word "reverse" is corrected by one character to "driving". (that's all)

Claims (1)

[Claims] 1. A bottomed hollow cylindrical body having an oil hole at the bottom;
a plunger that is slidably fitted into the body and forms a high pressure chamber between it and the inner surface of the bottom; and a plunger that is provided within the high pressure chamber and urges the plunger to move away toward the open end side of the body. A hydraulic valve gap automatic comprising an elastic body, a hydraulic lash adjuster comprising a check valve also provided in the high pressure chamber and controlling the opening and closing of the oil hole, and a check valve cage holding the check valve. correction device. 2. An oil sump chamber communicating with the pressure oil supply path is provided in the rocker arm, and the body of the hydraulic lash adjuster is supported in a support hole adjacent to the oil sump chamber so that the bottom thereof faces the oil sump chamber; The hydraulic valve gap automatic correction device according to claim 1, wherein the plunger is arranged so that the outer end of the plunger comes into contact with the head of the valve. 3. The hydraulic valve gap automatic correction device according to claim 1, wherein a separate oil reservoir chamber is attached to the bottom of the body of the hydraulic lash adjuster. 4. The hydraulic valve gap automatic according to claim 1, wherein a cylindrical oil reservoir chamber is integrally formed by extending the bottom peripheral edge of the body of the hydraulic lash adjuster in the opposite direction. correction device. 5. An oil inlet is provided in the oil sump chamber according to claim 3 at an end that does not face the hydraulic lash adjuster, and the combination of the oil sump chamber and the hydraulic lash adjuster is supported on a rocker arm. Claims 1 and 3, characterized in that the oil supply passage provided in the rocker arm is fitted into the hole and communicates with the oil inlet.
Hydraulic valve gap automatic correction device as described in . 6. The extended cylindrical portion of the body according to claim 4 is fitted into a support hole in a rocker arm, and an oil supply passage provided in the rocker arm and an oil reservoir chamber of the body are fitted. The hydraulic valve gap automatic replenishing device according to claims 1 and 4, characterized in that the automatic valve gap replenishing device is in communication with the valve gap replenishing device.