JPH0324810Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial application field This invention relates to a sealed hydraulic lifter that automatically adjusts the valve clearance for absorbing thermal expansion differences and maintains it at zero at all times in the valve mechanism of an internal combustion engine. It is something.

2. Description of the Related Art A valve mechanism for driving intake and exhaust valves in an internal combustion engine, for example, as shown in FIG. The opening/closing operation of the valve stem 3 is controlled by returning the valve stem 3 with a valve spring 4 wound around the valve spring 4 .

By the way, in this type of valve train mechanism, in order to absorb the difference in thermal expansion caused by the rise in engine temperature when the valve is driven, and to reliably close the valve stem 3 in response to various engine temperatures. , a minute valve gap is provided between the contact point between the rocker arm 2 and the valve stem 3. However, such a valve gap generates a collision sound when the valve is driven, causing noise, and at the same time, the valve cannot be controlled during high-speed operation, causing exhaust pollution. Also, valve clearance often requires adjustment,
With a multi-cylinder mechanism, this work was complicated and troublesome.

Therefore, in order to solve the various problems caused by the above-mentioned valve gaps, we developed a sealed system that uses hydraulic pressure with appropriate viscosity and incompressibility to eliminate valve gaps and automatically absorbs dimensional changes due to thermal expansion. Hydraulic lifters began to be used. In this system, oil is filled between the lifter and the plunger, which move relative to each other, and when the valve is opened, the two are operated together by hydraulic pressure, and when the valve is closed, they are separated, eliminating the valve gap. The conventional sealed hydraulic lifter A of this type is the 7th type.
As shown in FIG. 8 and FIG. 8, a plan in which a bottomed cylindrical lifter 6 is slidably accommodated in a bottomed cylindrical guide 5, and the bottomed cylindrical lifter 6 serves as a piston. The plunger 7 is slidably inserted into the inner bottom of the lifter 6 and the lower recess 7a of the plunger 7.
An oil chamber 8 is formed between the lifter 6 and the plunger 7, and an oil reservoir chamber 9 is formed between the small diameter shaft portion 7b of the plunger 7 and the inner peripheral surface of the lifter 6. A plunger spring 10 is provided to apply elasticity in the direction of separating the oil chamber 8 and the oil reservoir chamber 9 from each other, and an oil reservoir chamber 9 is provided between the oil chamber 8 and the oil passage hole 11 that communicates the oil chamber 8 and the oil reservoir chamber 9. A one-way valve 15 consisting of a check ball 12, a spring 13, and a retainer 14 is provided between the lifter 6 and the plunger 7 to prevent oil from leaking to the outside and to prevent oil from leaking to the outside. An elastic seal 16 is provided on the outer periphery of the lifter 6 to prevent the intrusion of impurities from the oil and absorb the volumetric expansion of the oil due to temperature rise.
A bottomed cylinder 17 fixed to the inner periphery of the guide 5 and the plunger 7 is installed between the guide 5 and the plunger 7, and the oil chamber 8, the oil reservoir chamber 9, and the oil passage hole 11 are installed.
A certain amount of oil is filled inside. Note that 18 is a lock ring attached to the open end of the guide 5, which regulates the amount of sliding of the lifter 6 and prevents each member from coming off.

The sealed hydraulic lifter A with the above configuration is
As shown in FIG. 9, the guide 5 is fitted into the cavity 2a of the rocker arm 2, and the spherical end of the lifter 6 is supported in contact with the upper end surface of the valve stem 3, so that the guide 5 is inserted between the rocker arm 2 and the valve stem 3. It is located in

Next, its effect will be explained. In the state shown in FIGS. 7 and 9, when the rocker arm 2 swings due to the rotation of the timing cam 1 and the plunger 7 starts descending via the guide 5 and the bottomed cylinder 17, the inside of the oil chamber 8 The pressure increases, and the check ball 12 of the one-way valve 15 closes the oil passage hole 11, preventing oil from flowing into the oil chamber 8. As a result, hydraulic pressure is generated in the oil chamber 8, and the force of the plunger 7 is increased. lifter 6
The lifter 6 descends together with the plunger 7 to push down the valve stem 3 and open the valve stem 3. At this time, a small amount of oil in the oil chamber 8 leaks from between the sliding surfaces of the lifter 6 and the plunger 7 and flows into the oil reservoir chamber 9, and the lifter 6 reduces the volume of the oil chamber 8 relative to the plunger 7. The distance between the two becomes slightly shorter as the two move relative to each other in the direction shown in FIG. Then, when the timing cam 1 further rotates, the pressing force on the rocker arm 2 is removed, and the hydraulic lifter A rises due to the urging force of the valve spring 4 wound around the valve stem 3, the plunger spring 10 Since the lifter 6 moves relatively in the direction of increasing the volume of the oil chamber 8, the inside of the oil chamber 8 becomes negative pressure, and the check ball 1 of the one-way valve 15
2 descends against the spring 13 to open the oil passage hole 11.
is opened, the oil in the oil reservoir chamber 9 flows back into the oil chamber 8 through the oil passage hole 11, the axial length between the lifter 6 and the plunger 7 is extended, and at the same time the valve stem 3 is closed, the valve gap is closed. automatically adjusts to zero.

Problems to be solved by the invention By the way, in this type of sealed hydraulic lifter A, since the rocker arm 2 swings, the lifter 6
and the valve stem 3 are not always in contact at one point. As a result, when the rocker arm 2 swings, the lifter 6 is caused by friction with the valve stem 3.
Since a rotational force is generated and a relative rotation occurs between the lifter 6 and the plunger 7, the elastic seal 16 may be twisted, and the elastic seal 16 may not be able to absorb the volume change due to oil expansion or may break early. There is a risk that

Means for Solving the Problem This invention consists of a bottomed cylindrical guide, a lifter and a plunger slidably disposed within the guide, and an oil formed between the plunger and the lifter or guide. A one-way valve is disposed in the middle of communication between the chamber and an oil reservoir formed on the other side of the plunger, and allows oil to flow only from the oil reservoir to the oil chamber; A plunger spring that constantly presses down, an annular elastic seal having folds with a U-shaped cross section that seals the oil chamber and the oil reservoir chamber, and a ring-shaped elastic seal that is attached to the open end of the guide and regulates the amount of sliding of the lifter, and In a sealed hydraulic lifter equipped with a lock ring that prevents a member from being pulled out, a cutout surface is formed on the outer peripheral surface of the lower end of the lifter,
On the other hand, a regulating surface is formed around the opening of the lock ring, and the cutout surface of the lifter and the regulating surface of the lock ring are fitted together.

Function The cutout surface of the lifter is formed by partially cutting off the outer peripheral surface of the lower end of the lifter or by providing a recess such as a groove. On the other hand, the regulating surface of the lock ring is formed by providing a protrusion corresponding to the notch surface of the lifter on the inner peripheral edge of the opening.

In a sealed hydraulic lifter in which a lifter and other members are housed in a guide that opens at the lower end, the cutout surface of the lifter and the regulating surface of the lock ring engage to prevent the lifter, etc. from slipping out of the guide. , to prevent relative rotation between the lifter and the guide. As a result, twisting of the elastic seal interposed between the lifter or between the plunger and the guide that is in pressure contact with the lifter is prevented.

Embodiment FIGS. 1 and 2 are a vertical sectional view and a bottom view showing an embodiment of a sealed hydraulic lifter according to the invention. The guide is a bottomed cylindrical guide fitted into the cavity 2a of No. 2, and has a stopper portion 21a protruding from its inner bottom. 22 is guide 2
The lifter is a cylindrical lifter with a bottom that is slidably inserted into the lifter 1 and has a cutout surface 22a formed at a symmetrical position on the outer periphery of the lower end thereof. 23 is a plunger that is slidably inserted into the lifter 22, and the lower recess 23
an oil chamber 24 is formed between the inner bottom part of the lifter 22 and the upper small diameter shaft part 23b and the lifter 22
An oil reservoir chamber 25 is formed between the inner circumferential surface of the oil chamber 24
The oil reservoir chamber 25 is communicated with the oil reservoir chamber 25 through an oil passage hole 26. 27
is a one-way valve composed of a check ball 28, a spring 29, and a retainer 30 that allows oil to flow only from the oil reservoir chamber 25 to the oil chamber 24, and the retainer 30 is fitted and fixed in the lower recess 23a of the plunger 23, A check ball 28 and a spring 29 are housed in a housing chamber 30a formed in the center of the retainer 30, and the check ball 28 closes the oil passage hole 26 of the plunger 23. The retainer 30 has a flow window 31 through which oil can flow to an appropriate location.
is formed. A plunger spring 32 is disposed within the oil chamber 24 and applies elastic force in a direction that separates the lifter 22 and plunger 23 from each other. Reference numeral 33 denotes an elastic seal which is sandwiched between the inner circumferential surface of the lifter 22 and the small diameter shaft portion 23b of the plunger 23 to seal the upper end of the oil reservoir chamber 25 and absorb the volumetric expansion of the oil due to temperature rise. , which has a U-shaped cross section and an annular shape, has a reinforcing ring 34 embedded in its outer end, and integrally attaches a thin-walled bottomed cylinder 35 drawn by a press to its inner end. The outer end side is press-fitted into the inner peripheral surface of the opening of the lifter 22, and the bottom cylinder 35 is inserted into the plunger 2.
It is interposed between the small diameter shaft portion 23b of No. 3 and the stopper portion 21a of the guide 21. 36 is guide 2
A locking ring made of an annular thin-walled iron plate is crimped and fixed to an annular groove 21b formed on the outer circumferential surface of the opening of No. 1, and a regulating surface 36a shaped along the notch surface 22a of the lifter 22 is formed at a symmetrical position on the periphery of the opening. By fitting the outer circumference of the lower end of the lifter 22 into the opening, it allows relative movement in the axial direction between the guide 21 and the lifter 22, prevents relative rotation, and prevents the lifter 22 from coming out from the guide 21. prevent

In the sealed hydraulic lifter constructed as described above, the oil chamber 24, oil reservoir chamber 25, and oil passage hole 26 are filled with oil, and its operation is the same as that of the conventional one. rocking,
When the plunger 23 starts descending via the guide 21 and the bottomed cylinder 35, the pressure inside the oil chamber 24 increases and the check ball 28 of the one-way valve 27
closes the oil passage hole 26 and the oil in the oil chamber 24 does not flow out, and as a result, hydraulic pressure is generated in the oil chamber 24 and the force of the plunger 23 is transmitted to the lifter 22, and the lifter 22 is connected to the plunger 23. descending as one,
Push down on the valve stem 3 to open the valve stem 3. At this time, a small amount of oil in the oil chamber 24 leaks between the sliding surfaces of the lifter 22 and the plunger 23, and the oil reservoir chamber 24 leaks.
5, the lifter 22 moves relative to the plunger 23 in a direction that reduces the volume of the oil chamber 24, and the distance between them becomes slightly shorter. Then, the timing cam 1 rotates further, the pressing force on the rocker arm 2 is removed, and the hydraulic lifter A is
When the lifter 22 rises, the plunger spring 32 moves the lifter 22 against the plunger 23 into the oil chamber 2.
4, the oil chamber 24 becomes negative pressure, and the check ball 28 of the one-way valve 27 descends against the spring 29 to open the oil passage hole 26 and open the oil reservoir chamber 25. The oil inside returns to the oil chamber 24 through the oil passage hole 26, and the lifter 22
The axial length between the valve stem 3 and the plunger 23 is extended to close the valve stem 3, and at the same time, the valve clearance is automatically adjusted to zero. In addition, even if oil expands in volume due to a rise in engine temperature when the valve is driven, the elastic seal 33
flexes to absorb the expansion, keeping the oil at approximately atmospheric pressure and preventing malfunctions. Furthermore, even if rotational force is applied to the lifter 22 due to contact with the valve stem 3 when the valve is driven, the restriction surface 36a of the lock ring 36 fixed to the outer peripheral surface of the opening of the guide 21 and the lifter 22
Since the notch surfaces 22a of the lifter 22 are fitted together, rotation of the lifter 22 can be prevented, and deformation and damage of the elastic seal 33 due to stiffness can be prevented, allowing stable and accurate driving at all times. Furthermore, the lock ring 36 can be easily manufactured by press working.

3 and 4 are drawings showing other modified examples of the lock ring 36. In FIG. 3, the lower end outer periphery of the lifter 22 is formed to have a stepped small diameter, and a notched groove 22b is formed in a part of the lower end outer periphery. On the other hand, the inner diameter of the opening of the lock ring 36 is made larger than the inner diameter of the guide 21 to prevent the lifter 22 from coming off the guide 21. A protrusion 36b extending toward
This protrusion 36b is fitted into the notch groove 22b of the lifter 22 to prevent rotation of the lifter 22. In this case, the notch groove 22b and the protrusion 36b are respectively similar to the embodiment shown in FIG. This corresponds to the cutout surface 22a and the restriction surface 36a. Figure 4 shows notched grooves 2 at three locations on the outer circumference of the lower end of the lifter 22.
On the other hand, a protrusion 36c is formed on the opening periphery of the lock ring 36 to face the notch groove 22c of the lifter 22 and extend radially inward, and the protrusion 36c of the lock ring 36 is formed in the notch groove 22c of the lifter 22. The notch groove 22c and the protrusion 36c are fitted into the notch surface 22a and the protrusion 36c of the embodiment shown in FIG. 1, respectively, to prevent the lifter 22 from rotating and from coming off the guide 21. This corresponds to the regulation surface 36a.

FIG. 5 shows an embodiment in which this invention is applied to a hydraulic lifter having a different structure, and shows the same contents as FIG. 1, and its functions and effects are the same as those of the previous embodiment.

Effects of the invention According to this invention, it is possible to prevent the lifter from rotating through the lock ring, thereby preventing the deformation and damage of the elastic seal and ensuring stable operation. We can provide various types of sealed hydraulic lifters.

In addition, with this invention, an engaging protrusion is provided on the lock ring attached to the outer circumferential surface of the open end of the guide, and an engaging recess is provided on the outer circumferential surface of the lower end of the lifter. The lifter guide surface is secured. Therefore, the guidance for the lifter is stable even when a moment load is applied, and smooth operation is always maintained.

[Brief explanation of the drawing]

Figures 1 and 2 are drawings showing an embodiment of the sealed hydraulic lifter according to this invention.
A vertical sectional view taken along the line - in the figure, and FIG. 2 is a bottom view thereof. 3 and 4 are drawings showing modified examples of the lock ring, and FIG. 5 is a longitudinal sectional view of an embodiment in which this invention is applied to a hydraulic lifter with a different structure.
FIG. 6 is a drawing showing a general valve mechanism, FIGS. 7 and 8 are drawings showing a conventional sealed hydraulic lifter, and FIG. 7 is a longitudinal sectional view taken along the line - in FIG. 8. FIG. 8 is a bottom view thereof. FIG. 9 is a drawing showing a valve operating mechanism using a hydraulic lifter. 21... Guide, 22... Lifter, 23... Plunger, 24... Oil chamber, 25... Oil reservoir chamber, 26... Oil passage hole, 27... One-way valve, 32... Plunger spring, 33... Elastic seal, 36... Lock ring .

Claims (1)

[Scope of utility model registration request] (1) A bottomed cylindrical guide that is open at the lower end, a lifter and a plunger that are slidably disposed within the guide, and an oil chamber and a plunger formed between the plunger and the lifter or guide. A one-way valve is placed in communication with the oil sump chamber formed on the other side and allows oil to flow only from the oil sump chamber to the oil chamber, and a one-way valve is placed within the oil chamber to keep the lifter depressed at all times. plunger spring,
An annular elastic seal having folds with a U-shaped cross section that seals the oil chamber and the oil reservoir chamber and is attached to the outer peripheral surface of the open end of the guide to regulate the amount of sliding of the lifter and prevent each member from coming off. In a sealed hydraulic lifter equipped with a locking ring, a cutout surface is formed on the outer peripheral surface of the lower end of the lifter,
On the other hand, a sealed hydraulic lifter is characterized in that a regulating surface is formed on the inner periphery of the opening of the lock ring, and the cutout surface of the lifter and the regulating surface of the lock ring are fitted together.