JPS6316113A - Tappet mechanism with valve stroke holding device for internal combustion engine - Google Patents

Abstract

PURPOSE:To obtain a valve mechanism of high reliability and low cost, by connecting a valve-side lifter being in contact with an intake valve of exhaust valve, to a cam-side lifter being in contact with the cam side and making said valve case to operate by means of a releasing member to disconnect the above connection. CONSTITUTION:An intake or exhaust valve 25 and a cam 2 are able to move together by an inner lifter 19 and an outer lifter 16, the former lifter being inserted in the latter with a spring 21 provided in the inside of them and the both lifters being coupled to each other by steel balls 17. A lifter guide 6 is provided on the outer periphery of said outer lifter 16, and, in normal operation, said steel balls 17 and kept in position by said lifter guide 6 to keep said inner and outer lifters 19, 16 coupled together. To an outer ridge 7 of said lifter guide 6 engages the camping piece 13 of a rocking member 12, which rocks around a pivot 11. In low load operation, when a piston 14 is activated to push down said lifter guide 6 against said spring 31 to free said steel balls 17 from the connecting position, said inner and outer lifters are enabled to slide relative ly to make said valve 25 inoperative.

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Field of Industrial Application) The present invention relates to a valve train mechanism that has the function of appropriately stopping cylinders of an internal combustion engine.

(Prior Art) In recent years, there has been an increasing demand for energy conservation and fuel efficiency. Therefore, in order to reduce fuel consumption during actual use of internal combustion engines, a valve train mechanism has been developed that has the function of stopping cylinders as appropriate depending on the operating conditions of the internal combustion engine, and changing the number of operating cylinders and, ultimately, the operating displacement. Various methods are known.

As a valve train having the above mechanism,
The oil circulation system described in No. 0005 and the
There is a stepped rotation method described in No. 17406.

As shown in FIG. 7, the oil circulation system described in Japanese Utility Model Application No. 58-130005 has an inner bottom surface inside an inverted bottomed cylindrical outer tappet 52 that follows a cam 51, and an inner bottom surface at the base end of a valve 53. An oil chamber 55 is formed between the outer tappet 52 and the inner tappet 54 by slidably fitting an inverted bottomed cylindrical inner tappet 54 whose central portions are brought into contact with each other. When the valve 53 is in operation, the oil chamber 55 is filled with pressure oil to cause the outer tappet 52 to follow the inner tappet 54, and when the valve 53 is inactive, the pressure oil is removed to stop the operation of the valve 53.

In addition, the step method described in Utility Model Application No. 17406/1983 is based on the inner surface of an inverted bottomed cylindrical outer tappet 62 that follows the cam 61, and the base end of the valve 63, as shown in FIG. 8.9. an elastic body 65 that presses and biases the inner tappet 64 whose inner bottom surfaces are in contact with the inner tappet 64 in a direction in which these bottom surfaces are separated from each other;
The splines of the outer tappet 62 and the inner tappet 6
A rotation means 66 is provided for holding the splines No. 4 in a rotational position where they cannot be slid. And the valve 6
3, when the rotating means 66 is in operation, the outer tappet 62 and the inner tappet 64 are held in a non-slidable rotating position, and the inner tappet 64 is made to follow the outer tappet 62, and when in rest, the rotating means 66 is released. The outer tappet 62 and the inner tappet 64 are in a slidable state, and the operation of the valve 63 is stopped.

(Problems to be Solved by the Invention) However, each of the above methods has the following problems.

That is, in the oil circulation method, if impurities such as air get into the oil chamber 55, the above operation may not be performed reliably, and the pressure oil is Since the viscosity becomes high, there is a problem of poor response.

Furthermore, the stepped rotation method requires a separate rotating means for regulating the sliding movement of the outer tappet 62 and the inner tappet 64, resulting in an increase in the number of parts and an increase in manufacturing costs. - Therefore, the object of the present invention is to ensure reliable operation such as activation and stopping of the valve mechanism;
Another object of the present invention is to provide a valve mechanism with a stop function that can be implemented at low cost with a small number of parts.

Structure of the Invention (Means for Solving the Problems) In order to solve the above problems, the present invention connects the cam-side lifter that contacts the cam and the valve-side lifter that contacts the intake and exhaust valves to each other via an elastic member. A connecting member is provided between the cam-side lifter and the valve-side lifter to connect the two by being fitted in a slidable manner, and a connecting member is provided on the outside of both lifters. A method is adopted in which a release member is provided to release the lock.

(Function) When operating all cylinders by operating the intake and exhaust valves, a connecting member is positioned between the cam-side lifter and the valve-side lifter to lock them together.

Then, since the cam-side lifter and the valve-side lifter are connected by the connecting member, the pulp-side lifter follows the movement of the cam-side lifter, and the intake and exhaust valves operate.

When stopping the intake and exhaust valves to bring the cylinder to rest, the release member releases the engagement between the cam-side lifter and the pulp-side lifter of the connection member. Then, since the cam-side lifter and the valve-side lifter are disconnected from each other, the movement of the cam-side lifter is not transmitted to the valve-side lifter, and the intake and exhaust valves do not operate.

Furthermore, if the release member is operated from this state and the connecting member is disposed between the cam side lifter and the valve side lifter to lock them together, the cam side lifter and the valve side lifter are connected. The intake and exhaust valves operate again.

(Example) Next, an example in which the present invention is applied to an automobile internal combustion engine having an OHC valve mechanism will be described with reference to FIGS. 1 to 5.

A camshaft 3 that integrally includes a cam 2 for opening and closing intake and exhaust valves extends above the cylinder head 1 . A guide hole 4 is provided through the cylinder throat 1 at a portion directly below the cam 2, and a cylindrical lid guide 6 serving as a release member is slidably inserted into the guide hole 4. At the upper part of the outer circumferential surface 6a of the lifter guide 6, a protrusion 7 that protrudes outward is formed over the entire circumference. A steel ball 18, which will be described later, is provided on the upper part of the inner circumferential surface 6b of the lifter guide 6.
An enlarged diameter part 8, in which the diameter enlarged part 8 is disposed, is recessed over the entire circumference, and a diagonal part 9 whose diameter gradually increases upward is provided in the groove between the inner circumferential surface 6a and the enlarged diameter part 8. ing.

A moving member 10 is attached to the outside of the protrusion 7 to sandwich the protrusion 7 and slide the lifter guide 6 along the guide hole 4.

This moving member 10 includes a long rotating member 12 having a rotating shaft 11 in the center, a pair of upper and lower clamping pieces 13 provided at the tip thereof, and a shaft at the base end of the rotating member 12. The cylinder 14 operates a piston rod 14a attached thereto. Therefore, when the cylinder 14 is actuated and its piston opening/nod 14a is pushed upward, the rotating member 11 rotates clockwise around the rotating shaft 11, and the clamping piece 13 at the tip thereof is designed to move downward.

An outer lifter 16 having a cylindrical shape with a bottom is slidably inserted inside the lifter guide 6.

Diagonal portion 9 of the lifter guide 6 of the outer lifter 16
In the lower part, cutouts 17 in the shape of an oblong sling 1 (four in this embodiment) are formed, and each cutout 17 has an outer lifter 16 as a connecting member for an outer lifter 16 and an inner lifter 19, which will be described later. A plurality of steel balls 18 having a diameter larger than the wall thickness are inserted.

An inner lifter 19 having an inverted bottomed cylindrical shape is slidably inserted inside the outer lifter 16 .

A locking recess 20 into which the inner portion of the steel ball 18 is fitted is formed over the entire circumference in a portion of the outer peripheral surface 19a of the inner lifter 19 facing the notch 17. Therefore,
When a portion of the steel ball 18 is fitted into the locking recess 20, the steel ball 18 is locked to both the outer lifter 16 and the inner lifter 19, thereby connecting them. The outer lifter 16 also moves following the movement of. Further, a coil spring 21 is installed in a compressed state between the top surface of the inner lifter 19 and the bottom surface of the outer lifter 16, so that no rattling occurs between them.

A recess 22 is formed in the upper surface of the inner lifter 19, and a shim 23 is fitted into the recess 22. The inner lifter 19 and the outer lifter 16 function as a conventional valve lifter.

Next, an intake valve (or exhaust valve, hereinafter abbreviated as valve) 25 is slidably inserted into the cylinder head 1, and the upper end of the valve stem 26 is located approximately at the center of the bottom surface of the outer lifter 16. It is in contact. A tipper 27 is attached to the upper end of the valve stem 26, and the tipper 27 is formed into a trapezoidal shape whose diameter decreases at the lower end. A valve spring retainer 28 is fitted around the outer periphery of the lever 27, and the tapered inner circumferential surface of the valve spring retainer 28 is in contact with the tapered outer circumferential surface of the lever 27. Also, valve spring retainer 2
A nozzle spring 30 is installed in a compressed state between the flange portion 8 and a support surface 29 provided within the cylinder head 1.

Furthermore, the lower end portion of the lifter guide 6 and the support surface 29
A guide spring 31 is also installed in a compressed state between. Therefore, when the lifter guide is pushed down and fixed in a downward position against the biasing force of the guide spring 31, when the fixation is released, the biasing force of the guide spring 31 returns it to the original position. He seems to be coming back quickly.

Regarding the embodiment configured as above, its operation and effects will be explained next.

First, when the load on the internal combustion engine is large and large torque and horsepower are required, all cylinders are used.

At this time, the cylinder 14 of the moving member 13 becomes inoperative and maintains the state shown in FIGS. 1 and 3.

That is, since the outer circumferential side of the notch 17 of the outer lifter 16 is blocked by the inner circumferential surface 6a of the lifter guide 6,
A steel ball 18 having a diameter larger than the wall thickness of the outer lifter 16
A part of the inner side thereof is fitted into the locking recess 20 of the inner lifter 19.

Therefore, the steel ball 18 is locked to both the outer lifter 16 and the inner lifter 19, and the outer lifter 16 and the inner lifter 19 are connected at this portion.

Therefore, when the cam 2 rotates and pushes down the upper surface of the shim 23, the shim 23 pushes down the inner lifter 19. Then, the force applied to the inner lifter 19 is also transmitted to the steel ball 18 inserted into the locking recess 20, and tries to push down the steel ball 18. However, most of the steel ball 18 is inserted into the notch 17 and cannot move further outward or inward. Therefore, only the steel ball 18 cannot be lowered, and the outer lifter Push down the entire 16. This outer lifter 1
6, the valve stem 26 which is in contact with the bottom surface of the valve stem 26 descends against the biasing force of the valve spring 30, and the valve 25 opens.

Therefore, as the cam 2 rotates, the valve 25 operates and the engine operates as a normal internal combustion engine.

Next, if the load on the internal combustion engine is small and a small torque or horsepower is sufficient, it is not necessary to operate all cylinders, and some cylinders are deactivated.

At this time, the cylinder 14 of the movable member 13 is activated, resulting in the state shown in FIG. 4.5.

That is, the cylinder 14 of the moving member 10 is actuated to push up the piston rod 14a.

By this pushing up, the rotating member 12 rotates clockwise about the rotating shaft 11, and moves the holding piece 13 downward. As the clamping piece 13 moves, the clamping piece 13
Since the protrusion 7 held between the lifter guides 7 and 7 is moved downward, the lifter guide 6 also moves downward along the guide hole 4 against the elastic force of the guide spring 31.

Furthermore, since the outer lifter 16 and the inner lifter 19 are constantly moving up and down due to the rotation of the cam 2, the force due to their up and down movement is constantly applied to the inside of the steel ball 18, and this force always pushes the S4 ball 18 outward. about to jump out. Therefore, when the enlarged diameter portion 8 faces the notch 17 of the outer lifter 16, the steel ball 18
is quickly moved into the enlarged diameter portion 8 by this force.

Then, the outer lifter 16 and the inner lifter 19 can no longer be connected, and therefore move independently. Therefore, even if the shim 23 is pushed down by the rotation of the cam 2, the outer lifter 16 will not move downward, and only the inner lifter 19 will be pushed down by the cam 20.
It follows the rotation and repeats vertical movement. Therefore, the cam 2
Since the valve 25 does not move according to the rotation of the cylinder, this cylinder can be brought into a rest state.

Further, when the cylinder is to be operated again from the above state, the cylinder 14 of the moving member 10 is operated to push down the piston rod 14a.

Then, the lifter guide 6 moves upward together with the biasing force of the guide spring 31. During this movement,
The steel ball 18 moves inward from the enlarged diameter portion 8 through the slanted portion 9, and is moved into the notch 17 by being gradually subjected to an inward force by the slanted portion 9. Further, the inner lifter 19 repeatedly moves up and down according to the rotation of the cam 2, and the locking recess 20 and the notch 1
7 are opposed to each other, a portion of the steel ball 18 is quickly fitted into the locking recess 20 of the lifter guide 6 due to the inward force, and the inner lifter 19 and the outer lifter 1
6.

In this way, the inner lifter 19 and the outer lifter 16 are reconnected and operate as a normal internal combustion engine.

As described above, according to this embodiment, the locking recess 2 of the steel ball 18
0, the steel ball 18- is inserted into the inner lifter 1.
9 and the outer lifter 16, and this locking connects the two, it is possible to stop the valve 25 with a very simple structure, and since hydraulic pressure is not used, it is possible to stop the valve 25 from the initial stage of engine startup. Responsiveness can also be maintained and reliability can be improved.

In addition, since the moving member 10 for vertically moving the lifter guide 6 is composed of a hydraulic cylinder 14 and a rotating member 12 that is rotated by the cylinder 14, the structure is not only simple but also compact. is also possible.

Furthermore, since the entire suspension mechanism can be constructed with a very small number of parts, it can be manufactured at low cost.

Further, since a plurality of the steel balls 18 are used, the load applied to the solid steel ball 18 and the load applied to one locking recess 20 are reduced, and durability and reliability are improved.

Note that the present invention is not limited to the above embodiments,
For example, it is also possible to implement the following modifications.

(1) In this embodiment, the hydraulic cylinder 14 is used as a means for moving the moving member 10, but of course an air cylinder may also be used.Furthermore, an electromagnetic solenoid, a screw rotation method, a jQ alloy shape etc. May be used.

(2) As for the movable member 10, as in this embodiment, the rotating member 12 is rotated to push down the protrusion 7, but a lever may be attached to the lifter guide 6 to directly move it up and down.

(3) In addition to the steel balls 18 of this embodiment, the connecting members include
As shown in FIG. 6, the connecting member may have a shape consisting of a cylindrical base 33 and a conical portion 34 at its tip, and the conical portion 34 may be inserted into the locking recess 20. Further, in the above shape, the base 33 may be a prism,
The conical portion 34 may be a pyramid. Furthermore, ceramic may be used as the material for this connecting member.

(4) In the above embodiment, the inner lifter 19 that contacts the cam 2 is placed inside, and the outer lifter 16 that contacts the valve 25 is placed outside and they are slidably fitted to each other. It is also possible to make it inside. However, in this case, it is necessary to provide the inner lifter 19 with the notch 17 and the outer lifter 16 with the locking recess 20.

(5) In this embodiment, the inner lifter 19 is provided with the shim 23, but the inner lifter 19 may be provided with no shim.

(6) It is also possible to embody the present invention in an OHV valve mechanism.

ADVANTAGES OF THE INVENTION As described in detail above, the present invention has the excellent effect of being able to provide a valve train having a highly reliable and responsive stop function at a low cost with a small number of parts.

[Brief explanation of the drawing]

1 to 5 show an embodiment embodying the present invention.
The figure is a sectional view showing the entire valve mechanism with a stop function, Figure 2 is a sectional view showing the connecting member part of Figure 1, and Figure 3 is a sectional view showing the valve operating state with the cam facing upward. Figures 4 and 5 show the valve at rest, Figure 4 is a sectional view showing the cam facing downward, Figure 5 is a sectional view showing the cam facing upward, and Figure 6. 7 is a sectional view showing another example, FIG. 7 is a sectional view showing a conventional example, and FIGS. 8 and 9 are also sectional views showing another conventional example. FIG. be. 2. Cam 6. Lifter guide 10. Moving member
16...Outer lifter 17...Notch part 18...t[1
9-.Inner lifter 20..Latching recess 21..Coil spring 25..Intake valve. Figure 7

Claims (1)

[Claims] 1. A cam-side lifter (19) that contacts the cam (2) and a valve-side lifter (16) that contacts the intake and exhaust valves (25) are slid together via an elastic member (21). A connecting member (18) is provided between the cam-side lifter (19) and the valve-side lifter (16) to connect the two by being engaged with each other so that the two lifters ( 16
, 19) is provided with a release member (6) for releasing the locking of the connecting member (18). 2. The valve side lifter (16) has the connecting member (1
A notch (17) into which the connecting member (18) is inserted is provided, and a locking recess (20) into which a part of the connecting member (18) is fitted is formed in the cam side lifter (19). A valve mechanism with a stop function in an internal combustion engine according to claim 1, characterized in that: 3. A pause function in an internal combustion engine according to claim 1, wherein the connecting member (18) is a plurality of steel balls having a diameter larger than the wall thickness of the valve side lifter (16). Valve mechanism with attached. 4. The valve mechanism with a pause function for an internal combustion engine according to claim 1, wherein the release member (6) is operated by a moving member (10) attached to a part thereof.