JPS5910327Y2 - Valve gap automatic adjustment device - Google Patents

Description

[Detailed description of the invention] This invention relates to an automatic valve gap adjustment device that automatically adjusts the valve gap for absorbing thermal expansion difference and maintains it at zero at all times in the valve train of an internal combustion engine. The purpose is to improve

The valve drive mechanism of internal combustion engines, which has been widely used in the past, absorbs the difference in thermal expansion caused by the rise in engine temperature when the valve is driven.
A valve clearance is provided between the valve and the drive line to ensure that the valve closes in response to various engine temperatures.

This kind of valve clearance produces a collision sound when the valve is driven, causing so-called tappet noise, and also impairs the accuracy of valve opening and closing movements during high-speed operation, making it impossible to maintain perfect engine control. This caused exhaust pollution.

Therefore, in order to solve the various problems caused by the above-mentioned valve gaps, an automatic valve gap adjustment device has been developed that uses hydraulic pressure with appropriate viscosity and incompressibility to eliminate valve gaps and automatically expands and contracts to absorb the difference in thermal expansion. It came to be used.

This fills oil between the lifter and plunger, which move relative to each other, and when the valve opens, both are operated together by hydraulic pressure.
When the valve is closed, the two are separated by a predetermined amount to eliminate the valve gap.

As shown in FIG. 1, a conventional valve gap automatic adjustment device includes a flange 3 that functions as a piston and is slidably inserted into a cylindrical lid 2 that is reciprocated by a cam 1.
A ball seat 5 that supports the spherical end of the push rod 4 is fitted onto the upper end of the plunger 3.

An oil chamber 6 is formed between the bottom surface of the lifter 2 and the lower surface of the plunger 3, an oil reservoir chamber 7 is formed inside the plunger 3 along the axis, and its lower opening is positioned within the oil chamber 6. A one-way valve 11 is provided with a check ball 8, a spring 9, and a retainer 10, which communicate with each other and allow oil to flow only from the oil reservoir chamber 7 to the oil chamber 6. A plunger spring 12 is provided in the oil chamber 6 to push up the plunger 3 through the retainer 10, and press the check ball 8 on the spring 9 to bring it into contact with the valve seat 3a of the plunger 3 and close it. is provided.

13 is an oil supply hole formed on the side surface of the lifter 2, and 14 is an oil supply hole formed on the side surface of the plunger 3, both of which are connected to the lifter 2.
The plunger 3 is constantly in communication with the inner peripheral surface of the plunger 3 through a guide groove 15 formed on the outer peripheral surface of the plunger 3, and oil is supplied to the oil reservoir chamber 7.

Reference numeral 16 denotes a retaining ring installed in a circumferential groove 17 formed slightly below the open end of the lifter 2, which regulates the amount of sliding of the plunger 3.

To explain its action, when the valve is closed and no force is acting on the valve train, the plunger spring 12 in the oil chamber 6
The plunger 3 is pushed up by the stored elasticity, the one-way valve 11 is opened by the amount pushed up, oil is supplied from the oil reservoir chamber 7 into the oil chamber 6, and the space between the lifter 2 and the plunger 3 is extended. valve clearance is maintained at zero.

When the lifter 2 is pushed up by the cam 1 when the valve is driven, the one-way valve 11 is closed, the force is transmitted to the oil in the oil chamber 6, the plunger 3 rises together with the lifter 2, and the push rod 4 Push up to open the valve.

During this time, a small amount of oil in the oil chamber 6 leaks between the sliding surfaces of the lifter 2 and the plunger 3 and flows back into the oil reservoir chamber 7.

When the lifter 2 loses its pushing force and is pushed down by a valve spring (not shown) wrapped around the valve,
During the descent, the plunger spring 12 separates the lifter 2 and plunger 3, creating negative pressure in the oil chamber 6, and the check ball 8 opens against the spring 9, moving from the oil reservoir chamber 7 into the oil chamber 6. The liquid flows in, expands the space between the lifter 2 and the plunger 3, and corrects the valve clearance to zero.

Although the above-mentioned automatic valve gap adjustment device solved problems such as noise caused by the valve gap, it was difficult to assemble because it had many mechanical parts and was filled with oil.

That is, the plunger spring 12 is erected in the lifter 2, the check ball 8, the spring 9, and the retainer 10 are attached to the lower surface of the plunger 3, and then the plunger 3 is inserted with the lifter 2 filled with oil. , oil chamber 6
After removing air from the oil reservoir chamber 7 and filling it with oil, the ball seat 5 is fitted onto the upper end of the plunger 3, and the retaining ring 16 is attached to assemble it. A one-way valve 11 is provided between the chamber 6 and the oil reservoir chamber 7.
was installed, oil did not flow from the oil chamber 6 to the oil reservoir chamber 7, the oil pressure in the oil chamber 6 increased, and the plunger 3 could not be inserted into the lifter 2.

Therefore, in order to insert the plunger 3, use a suitable jig to release the check ball 8 of the one-way valve 11 from the valve seat 3a, allow oil to flow from the oil chamber 6 to the oil reservoir chamber 7, and insert the plunger. Alternatively, a relatively large load must be applied between the lifter 2 and the plunger 3 to allow oil to escape and fill the gap between the inner peripheral surface of the lifter 2 and the outer peripheral surface of the plunger 3, which requires special treatment during assembly. This method requires tools, jigs and devices that apply loads, and has the disadvantage that assembly is troublesome and time-consuming.

In view of the above-mentioned conventional drawbacks, this invention has been improved and eliminated, and includes a locking part that locks the check ball in the open position on the retainer of the one-way valve, and a release that releases the lock of the check ball and closes it. It is equipped with members.

The structure of this invention will be explained below with reference to the embodiments shown in the drawings.

In FIG. 2, 18 is a bottomed cylindrical lifter that is reciprocated by the cam 1, 19 is a plunger slidably inserted into the lifter 18, and a push rod 4 is attached to the upper end of the plunger.
A recess 19a is formed on the lower surface of the ball seat 20 for supporting the ball seat.

Reference numeral 21 denotes an oil chamber constructed between the inner bottom surface of the lifter 18 and the lower surface of the plunger 19, which communicates with an oil reservoir chamber 22 formed along the axis within the plunger 19, and is successively filled with an oil reservoir. Oil is supplied from the chamber 22 to the oil chamber 21.

23 is a one-way valve that only allows oil to flow from the oil reservoir chamber 22 to the oil chamber 21;
It is composed of a check ball 25 that seats and closes the valve seat, a spring 26 that presses the check ball 25 against the valve seat 24, and a retainer 27 that accommodates the check ball 25 and the spring 26 and is attached to the recess 19a of the plunger 19. As shown in FIG. 3, the retainer 27 has a housing chamber 28 in the center that accommodates a check ball 25 and a spring 26, and a check ball 25 with a diameter slightly smaller than that of the check ball 25 on the inner peripheral surface of the intermediate portion of the housing chamber 28. A locking portion 29 that locks the ball 25 and holds it in the open position is formed, and communication windows 30 through which oil flows are formed at appropriate positions on the bottom and side surfaces.

Then, a rod-shaped release member 31 is joined to the lower surface of the check ball 25 for removing the check ball 25 from the locking part 29 during assembly and seating it on the valve seat 24, and the lower end of this is connected to the retainer 2.
It is made to protrude downward from the communication window 30 on the lower surface of 7.

The length of this release member 31 is such that when the check ball 25 is locked in the locking portion 29, the plunger 19 is
8 and attach the retaining ring 33 to the circumferential groove 32 formed on the upper inner peripheral surface of the lifter 18.
When the check ball 25 is seated on the valve seat 24, even if the plunger 19 reaches the lowest position, it will not touch the inner bottom surface of the lifter 18. Set the length so that they do not touch each other.

Reference numeral 34 indicates an oil supply hole formed on the side surface of the lifter 18, 35 indicates an oil supply hole formed on the side surface of the plunger 19, and 36 indicates an oil supply hole formed on the side surface of the plunger 19.
Each oil supply hole 3 is provided on the inner peripheral surface of the plunger 18 and the outer peripheral surface of the plunger 19.
4, 35 with a shaped guide groove, lifter 1
Regardless of the relative positional relationship between the plunger 8 and the plunger 19, the oil supply holes 34 and 35 are always communicated with each other, so that oil can be continuously supplied from the outside (cylinder block) to the oil reservoir chamber 22.

Reference numeral 37 denotes a plunger spring disposed within the oil chamber 21, which applies elastic force in a direction to separate the lifter 18 and plunger 19 from each other.

In the valve gap automatic adjustment device constructed in this way, after assembly, the check ball 25 is pushed up by the spring 26 and the valve seat 2 is pushed up.
4, and its function is the same as that of the conventional one. When the lifter 18 is pushed up with the rotation of the cam 1 when the valve is driven, the plunger 19 follows and rises due to the hydraulic pressure in the oil chamber 21. Push up on the pushrod to open the valve.

When the lifter 18 descends, the plunger spring 37
The lifter 18 and plunger 19 are separated from each other, the check ball 25 of the one-way valve 23 is opened, and the oil reservoir chamber 2 is opened.
Oil is replenished into the oil chamber 21 from 2, the axial length of the lifter 18 and the plunger 19 is extended, and the valve clearance is maintained at zero.

Further, the one-way valve 23 of the automatic valve gap adjustment device is provided with a function to open the check ball 25, and can be easily assembled without using any special jig when setting the silk stand.

That is, during assembly, the check ball 2 is provided with the spring 26 and the release member 31 in the accommodation chamber 28 of the retainer 27 in advance.
5 is accommodated, the lower part of the release member 31 is made to protrude downward from the communication window 30, and the check ball 25 is pushed into the bottom side of the accommodation chamber 28 against the spring 26, and the upper peripheral edge is inserted into the locking part 2.
9 and hold it in the open position.

This retainer 27 is press-fitted into the lower recess 19a of the plunger 19 into which the ball seat 20 is fitted.

Next, the lifter 18 is filled with oil, and the plunger spring 37 is inserted and centered so that it stands up on the inner bottom surface, and then the plunger 19 is inserted into the lifter 18 and pushed against the plunger spring 37 to the lowest end. Push it into position.

Then, since the check ball 25 of the one-way valve 23 is held in the open position, the oil in the oil reservoir 21 is drained into the retainer 27.
The oil escapes through the communication window 30 into the oil reservoir chamber 22 and is smoothly inserted, and the release member 31 attached to the check ball 25 comes into contact with the inner bottom surface of the lifter 18 as shown in FIG. The descent of the ball 25 is stopped.

Thereafter, as the plunger 19 descends, the retainer 27 also descends, and as a result, the check ball 25 moves upward, overcomes the locking part 29, and is released from the lock, and from then on, the spring 2
Check ball 25 and release member 3 due to the stored elasticity of 6
1 is pushed up, and the check ball 25 seats on the valve seat 24 and closes the oil reservoir chamber 22.

When the plunger 19 is located at the lower end, the retaining ring 33
is fitted into the circumferential groove 32 to prevent the plunger 19 and the ball seat 20 from coming off, completing the assembly.

In this way, during the assembly process of filling oil into the oil chamber 21, the check ball 25 of the one-way valve 23 is open, making it easy to insert and push the plunger 19, and at the same time, the plunger 19 is completely pushed. At the same time, the check ball 25 can be released and seated on the valve seat 24 to close it, and a special jig or a device that applies a relatively large load between the lifter 18 and the plunger 19 can be used to open the check ball 25. No jigs are required, making assembly easy.

Further, after the assembly is completed, the check ball 25 is in a free state and is pushed up by the spring 26, so that it can operate without any problem and no malfunction will occur.

5 to 7 are drawings showing other embodiments of the one-way valve, in which 38 is a retainer that accommodates the check ball 25 and the spring 26, and 39 is a retainer that fixes and releases the check ball 25. It is a release member.

The retainer 38 is formed with slits 40 that serve as oil circulation windows in the vertical direction at an appropriate number of locations, and locking portions 41 and 42 that protrude inward at two locations above and below the side surface of the slits 40; The release member 39 slides inside the snot 46 onto a disk portion 43 whose inner diameter is slightly smaller than the check ball 25 and whose outer diameter is smaller than the accommodation chamber 38a of the retainer 38, and is attached to the locking portions 41, 42. An arm part 44 is formed to be engaged with the arm part, and a leg part 45 is further formed to extend downward from the tip of the arm part.

When assembling, the spring 26 and the check ball 25 are housed in the housing chamber 38a of the retainer 38, and the release member 3
Shave the arm part 9 and make the leg part 45 protrude outward from the slit 40. In this state, push the release member 39 and slit the arm part 4.
0-shaped lower locking part 41.

Then, the check ball 25 is fixedly held at the lower part of the storage chamber 38a.

When the plunger 19 is attached to the recess 19 a and deeply inserted into the lifter 18 , the legs 45 come into contact with the inner bottom surface of the lifter 18 and rise relative to the retainer 38 . The check ball 25 passes over the stop portion 42 and is pushed up by the spring 26 to close the oil reservoir chamber 22.

As explained above, this idea consists of a lifter that reciprocates by the rotation of a cam, a plunger that is slidably disposed inside the lifter, an oil chamber formed between the bottom surface of the lifter and the bottom surface of the plunger, and the axis of the plunger. In the valve gap automatic adjustment device, the device includes a one-way valve disposed between the oil reservoir chamber and a plunger spring disposed within the oil chamber and pushing up a plunger. A retainer that accommodates the check ball of the directional valve is formed with a locking part that temporarily holds the check ball in the open position, and a release member that releases the check ball from the open position is operated in conjunction with the check ball. Since the check ball is installed and movable relative to the retainer, the check ball can be left open before assembly is completed, and oil circulation is easy. There is no need for a device or jig that applies a relatively large load between the lifter and the plunger, and when the assembly is completed, the check ball becomes free and is pushed up by the spring, closing the oil sump chamber and restoring its function. , there will be no malfunction, and the assembly work will be greatly simplified.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing the structure of a conventional hydraulic valve gap automatic adjustment device, Fig. 2 is a sectional view showing the structure of a valve gap automatic adjustment device according to the present invention, and Fig. 3 is a sectional view showing the structure of a conventional hydraulic valve gap automatic adjustment device. FIG. 4A is an enlarged sectional view of the main part showing a directional valve; FIG. 4A is an enlarged sectional view of the main part showing a part of the assembly process; FIGS. 5 is a sectional view showing an assembled state, FIG. 6 is an exploded perspective view thereof, and FIG. 7 is a schematic view showing the positional relationship between the retainer and the release member. 18...lifter, 19...plunger, 21...
・Oil chamber, 22... Oil reservoir chamber, 23... One-way valve,
25...Check ball, 26...Spring, 2
7... Retainer, 29... Locking part, 31... Release member.

Claims (1)

[Scope of utility model registration request] A lifter that reciprocates by the rotation of a cam, a plunger that is slidably disposed inside the lifter, an oil chamber formed between the bottom surface of the lifter and the lower surface of the plunger, and an oil reservoir shaped along the axis of the plunger. In an automatic valve gap adjustment device comprising a one-way valve disposed between a chamber and a plunger spring disposed within the oil chamber and pushing up a plunger, the retainer accommodates a check ball of the one-way valve. A locking part is formed to temporarily hold the check ball in the open position, and a release member for releasing the check ball from the open position is provided to operate in conjunction with the check ball, and is movable relative to the retainer. An automatic valve gap adjustment device characterized by: