JPH0217132Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to an intake/exhaust valve opening/closing device that opens and closes an intake/exhaust valve for a cylinder of an internal combustion engine at a predetermined timing.

[Prior art]

Four-cycle internal combustion engines such as gasoline engines and diesel engines are equipped with an intake valve that sucks combustion gas and air into the cylinder, and an exhaust valve that exhausts it from the cylinder. A switching device is provided to open and close this according to timing. FIG. 1 is a schematic configuration diagram of a conventional opening/closing device of this type, FIG. 2 is an enlarged sectional view of the vicinity of the opening/closing cam, and FIG. 3 is a lift curve diagram of an intake valve and an exhaust valve. In the figure, an exhaust valve 3 that opens and closes the exhaust hole 2 of a cylinder 1 is provided in the exhaust hole 2, and the upper end of the valve stem is vertically movable.
It is pivotally attached to one end of a lever 4 that is swingably supported on the cylinder case side. Further, a roller 6 is pivotally attached to the lower end of the push rod 5 which is pivotally attached to the other end of the lever 4, and this roller 6 is in contact with the cam surface of the opening/closing cam 7. The exhaust valve 3, lever 4, and push rod 5 are biased between the upper end pivot portion of the exhaust valve 3 and the cylinder case in the direction of closing the exhaust valve 3, that is, in the direction of pressing the rollers 6 against the cam surface of the cam 7. A valve spring 8 is interposed. When the opening/closing cam 7 rotates once per combustion cycle of the cylinder 1, the exhaust valve 3 moves up and down via the push rod 5 and lever 4, opening and closing the exhaust hole 2. Although the exhaust valve has been described above, the structure of the intake valve is the same as that of the exhaust valve 3, except that the opening/closing timing is different.

FIG. 3 is a lift curve diagram of the intake and exhaust valves and the exhaust valve, and the lift cover of the intake valve shown by the solid line S and the lift curve of the exhaust valve shown by the solid line E are shown in the diagram with reference symbols.
The piston top dead center indicated by TDC is overlapped to share the same position. Points indicated by symbols BDC ₁ and BDC ₂ in the figure are piston bottom dead centers corresponding to the intake valve and the exhaust valve, respectively. As shown by the solid line S, the intake valve starts opening before the top dead center TDC and reaches the bottom dead center.
The exhaust valve closes at BDC ₁ , and as shown by the solid line E, the exhaust valve finishes opening before bottom dead center BDC ₂ and starts closing before top dead center TDC. In other words, the lift curve S of the intake valve and the lift curve E of the exhaust valve are at the top dead center.
They overlap as shown by triangle ABC with TDC as the center. The area ABC indicating this valve overlap is generally determined by the shape of the opening/closing cam 7, and is a major factor that influences the performance of the internal combustion engine. In order to cause combustion, it is necessary to provide an appropriate valve overlap area for each load. In other words, for example, by controlling the opening timing of the intake valve and shortening the valve opening period, the lift curve of the intake valve can be made into a chain line S ₁ , and by doing the same with the exhaust valve, the lift curve can be made into a chain line E ₁ . It is necessary to make adjustments such as setting the valve polymerization area to A ₁ B ₁ C ₁ .

However, in the conventional device, the opening/closing cam 7 shown in FIG.
As shown in detail in the vicinity, the roller 6 for the opening/closing cam 7 explained in FIG. , its lower end spherical portion is directly supported by the spherical seat 11 integrated with the roller guide 10, so in order to advance or delay the valve opening/closing timing, the opening/closing cam 7 must be rotated to adjust the phase. Moreover, in order to lengthen or shorten the valve opening period, it is necessary to adjust, for example, the fulcrum position of the lever 4 in FIG. 1. Therefore, not only cannot be adjusted while the machine is running, but even if the machine is stopped to make adjustments, the work is troublesome and takes a long time, and proper adjustment cannot be expected.

[Summary of the idea]

The present invention was developed in view of the above points, and includes a plunger between a roller guide that supports the opening/closing cam roller and can move forward and backward, and a valve opening/closing push rod that can move forward and backward on the same axis as the roller guide. Pressure oil is introduced between the plunger and the push rod, and the rotation of the opening/closing cam opens and closes the intake and exhaust valves via the roller guide, plunger, pressure oil, and push rod. By providing a pinion and a pinion, the suction and pinion can be easily operated by moving the rack on the main body that engages the pinion forward and backward.
An object of the present invention is to provide an intake/exhaust valve opening/closing device for an internal combustion engine, which makes it possible to adjust the opening/closing timing and the opening/closing timing of an exhaust valve without stopping the operation of the engine. Embodiments of the present invention will be described in detail below with reference to the drawings.

〔Example〕

4 to 6 show an embodiment of the intake/exhaust valve opening/closing device according to the present invention, in which FIG. 4 is a sectional view of its driving part, FIG. 5 is an enlarged sectional view of the vicinity of the plunger head, and FIG. The figure is a developed view of the plunger head shown to explain the relationship between the notch and the oil hole. This embodiment shows an example in which the present invention is applied to intake/exhaust valves of a diesel engine, and the structure from the exhaust valve 2 to the push rod 5 shown in FIG. 1 is the same as the conventional one, so a description thereof will be omitted. However, if further explanation is required, it will be explained using the same figure. In the figure, a lower main body 21 of a driving section formed in a stepped cylindrical shape is fixed to a cylinder case 9 by a bolt inserted into a bolt hole 21a.
The small diameter portion 21b of 1 is connected to the shaft hole 9 of the cylinder case 9.
It is involved in a. Threaded portion 21 of lower body 21
An upper main body 22 formed in a cylindrical shape is concentrically screwed into the upper main body 22.
2 are screwed together.

Reference numeral 24 denotes an opening/closing cam disposed below the cylinder case 9, which is rotationally driven from the crankshaft side so as to rotate once per combustion cycle in synchronization with the reciprocating movement of a piston (not shown). , FIG. 4 shows a part of its outer periphery. In the shaft hole 9a of the cylinder case 9, a roller guide 25 integrally formed with a bottomed cylindrical portion 25a and a bifurcated shaft support 25b is provided so as to be movable up and down with the bottomed cylindrical portion 25a fitted. A roller 26 whose peripheral surface is in contact with the outer peripheral cam surface of the opening/closing cam 24 is pivotally supported on the shaft support 25b via a pin. 27 is a plunger holding hardware formed in a cylindrical shape with a flange at the lower end, and FIGS. 7a and 7b show a side view and a plan view of the upper end thereof, and FIGS. Similarly, an enlarged sectional view of the upper end portion and a side view of the main part are shown. A plunger push rod 28 having a flange at the lower end is fitted into the plunger holding hardware 27 and fixed integrally with a knock pin 29. A plunger 37, which will be described later, is inserted between the plunger push rod 28 and the upper end of the plunger holding hardware 27. A gap is provided for insertion. The plunger holding hardware 27 integrated with the plunger push rod 28 in this way is connected to the inner hole 21 of the lower body 21.
A compression coil spring 30 is inserted between the stepped portion of the lower main body 21 and the plunger holding hardware 27 and urges the roller guide 25 in a direction to bring the roller 26 into pressure contact with the cam surface of the opening/closing cam 24. It has been intervened. Further, the tip of a set screw 31 screwed into the lower body 21 is inserted into a long hole 27a provided on the circumferential surface of the plunger holding metal fitting 27, thereby allowing the rotation of the plunger holding metal fitting 27. is regulated and reciprocating movement is permitted.

On the other hand, the cylindrical upper barrel 32 fitted on the upper part of the upper main body 22 has a spherical seat 33 on the upper end surface.
A piston 33 having a diameter of 1.a is fitted in a reciprocating manner, and a spherical lower end of a push rod 5 similar to the conventional push rod 5 shown in FIGS. 1 and 2 is fitted into the spherical seat 33a. The push rod 5 is pressed against the spherical seat 33a of the piston 33 by the elastic force of the valve spring 8 shown in FIG. Downward movement is restricted. In addition, in the conventional device shown in FIG. 1, the elastic force of the valve spring 8 acts up to the roller 6, but in this device, it only acts up to the push rod 5, and another force is applied to the roller 26. The elastic force of the spring 30 is acting. Large diameter portion 33 of piston 33
A drain hole 22a is opened at the bottom of the inner hole of the upper main body 22 into which the upper body 22 is fitted.
a is connected to the hydraulic circuit via a selectively switchable pressure accumulator 34 and a throttle 35.

Furthermore, a lower barrel 3 is provided in the inner hole of the upper body 22.
6 are continuously fitted into the upper barrel 32,
A plunger, generally designated by reference numeral 37, is fitted into the inner hole and the inner hole of the lower main body 21 so as to be able to reciprocate. As shown in FIGS. 7a and 7b, this plunger 37 has a lower end flange 37a inserted into a gap above the plunger push rod 28 from the U-shaped opening of the plunger holding hardware 27, thereby holding the plunger. It reciprocates integrally with the metal fitting 27 and is rotatable relative to the plunger holding metal fitting 27 which is stationary in the rotational direction. Fourth
The figure shows the plunger 37 descending as the rollers 26 come into contact with the valve open position of the opening/closing cam 24, and the lower barrel 36 and the upper main body 22 are
An oil hole 38 corresponding to the upper end surface of the lowered plunger 37 is provided and connected to a hydraulic circuit. The space 39 between the upper end surface of the plunger 37 and the lower end surface of the piston 33 is always filled with pressure oil flowing from the oil hole 38.
rises and closes the oil hole 38 with its circumferential surface, leaving no place for the pressure oil to escape, and the plunger 37
, and the piston 33 is configured to rise integrally with the plunger 37.

The plunger 37 is provided with an adjusting device that changes the closing timing and closing period of the oil hole 38 to adjust the valve opening/closing timing and the valve opening period. I will explain. In the figure, a pair of upper and lower notches 40 and 41 having a length of approximately 1/3 of the total circumference are provided on the outer circumferential surface of the head of the plunger 37 at different phases in the circumferential direction. 41 is formed in an inclined shape so as to become gradually deeper in the axial direction as it goes in the circumferential direction. Further, below the lower notch 41, an annular groove 42 extending over the entire circumference is provided below the notch 41.
The annular groove 42 and the space 39 above the plunger 37 are connected by a communication hole 43 passing through the center of the plunger 37 and a communication hole 44 extending radially from the lower end thereof. It is communicated. Therefore, the inside of the space 39 and the annular groove 42
The same oil pressure is always maintained inside. On the other hand, the outer periphery of the plunger 37 that fits into the inner hole 21a is toothed to form a pinion 45, and the lower body 21 has a rack 46 that engages with the pinion 45.
is supported so as to be reciprocally movable, with its rotation being restricted by a set screw 47. By moving the rack 46 forward and backward, the plunger 37 is rotated back and forth in forward and reverse directions, and the relative position between the oil hole 38 and the outer periphery of the plunger 37 is changed. FIG. 6 illustrates four relative positions between the oil hole 38 and the plunger 37, which are obtained by rotating the plunger 37, and are respectively indicated by symbols, , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , 10, and 19, respectively. When the plunger 37 is raised, the oil hole 38 is closed by the circumferential surface of the plunger 37 and opened by facing the annular groove 42, so that the oil hole 38 has the longest closing time at the position indicated by the symbol. On the other hand, at the position indicated by the symbol, the notch 40 corresponds to the oil hole 38, so that the oil hole 38 begins to close later than at the position indicated by the symbol, and opens in the same manner as in the case indicated by the symbol.
Further, at the position indicated by the symbol, the timing at which the oil hole 38 begins to close is further delayed, and since it faces the notch 41, the timing at which the oil hole 38 begins to open is earlier. Therefore, in this case, the period during which the oil hole 38 is closed is the shortest. Further, at the position indicated by the symbol, the oil hole 38 faces only the notch 41, so that the oil hole 38 starts to close quickly and also starts to open quickly. Then, the plunger 37 rises and the oil hole 38
When the pressure oil is closed, the exhaust valve 2 is opened via the compressed pressure oil and the piston 33 and the push rod 5, etc., and when the plunger 37 is further raised and the oil hole 38 is opened, the compressed pressure oil is released from the oil hole 38. Since the gas is discharged, the elastic force of the valve spring 8 causes the exhaust valve 2 to close. That is, by adjusting the closing timing and closing period of the oil hole 38, the opening/closing timing and opening/closing period of the exhaust valve 2 are adjusted.

Although the exhaust valve opening/closing device has been described above, the intake valve may be provided with an opening/closing device having the same configuration as this, or may have the same configuration as the conventional one shown in FIGS. 1 and 2. Good too. In this embodiment, the present invention is implemented only on the exhaust valve side, and an opening/closing device having the same structure as the conventional one is provided on the intake valve side.

The operation of the intake/exhaust valve opening/closing device configured as above will be explained. When the crankshaft rotates, a piston reciprocates within the cylinder 1, fuel is injected, and the opening/closing cam 7 for the intake valve and the opening/closing cam 7 for the exhaust valve rotate in synchronization. Among these, when the opening/closing cam 7 for the exhaust valve 3 rotates and the corresponding part of the roller 26 moves from the small diameter part to the large diameter part of the cam 7, the roller guide 25 supporting the roller 26 and the compression coil spring are connected to the roller guide 25 that supports the roller 26. Plunger holding hardware 2 pressure-welded at 30
7 and the plunger push rod 28 rise while compressing the spring 30, and the plunger 37 held in the upper end gap of the plunger holding metal fitting 27 also rises while sliding the teeth of the rack 46 and pinion 45. When the plunger 37 rises and its peripheral surface closes the oil hole 38, the pressure oil in the space 39 has no place to escape and is compressed by the plunger 37. The push rod 5 that is pressed by the elastic force rises due to the hydraulic pressure exceeding the spring pressure of the valve spring 8, and the exhaust valve 3 is pressed against the valve spring 8.
Open while compressing. When the plunger 37 further rises and the annular groove 42 faces the oil hole 38, the space 39 and the oil hole 38 communicate with the oil hole 38 through the communication holes 43, 44 and the annular groove 42, so the plunger 37 compresses the oil. The pressurized oil that has been pressurized is released from pressure and is discharged from the oil hole 38 through the communication holes 43 and 44. At the same time, the corresponding part of the roller 26 moves from the large diameter part to the small diameter part of the opening/closing cam 24, so that the plunger holding metal fitting 27 is pressed against the cam surface of the opening/closing cam 24 by the elastic force of the compression coil spring 30. As the plunger 37 is held and lowered, the push rod 5 is lowered together with the piston 33 by the elastic force of the valve spring 8, and the exhaust valve 3 is closed. As described above, the opening/closing operation of the exhaust valve 3 is the operation shown by the symbols in FIG. FIG. 9 is a lift curve diagram corresponding to FIG. 3, and when indicated by the reference numerals in FIG. 6, the lift curve is the curve shown by the solid line _E2 in FIG.

If you want to delay the opening time while leaving the closing timing of the exhaust valve 3 as it is, by moving the rack 46 forward and backward, the pinion 45 that meshes with it will rotate and open the notch as shown by the symbol in FIG. 40 corresponds to the oil hole 38, so even if the plunger 37 is raised by the opening/closing cam 24 having the same shape as in the case of the symbol, the action of the notch 40 delays the closing of the oil hole 38 and the start of compression of the pressure oil. I'll be late. Therefore, even if the plunger 37 moves up, the push rod 5 follows it with a slight delay and starts moving up, thereby delaying the opening timing of the exhaust valve 3. The valve closing timing is the same as indicated by the symbol. The lift curve in this case is shown by the dotted line in Figure 9.
Shown as _E3 . Next, if you want to further delay the opening timing of the exhaust valve 3 and advance the closing timing, use Rack 46.
When the plunger 37 is further rotated by the operation,
The oil hole 38 is located in the notch 4 as indicated by the symbol in FIG.
Since it corresponds to the deep part of 0 and the middle part of the notch 41, the plunger 37 is connected to the open/close cam 24 of the same shape.
Even if the oil hole 38 is raised, due to the action of the notches 40 and 41, the closing of the oil hole 38 is delayed and the opening is premature, so that the lift curve of the exhaust valve 2 becomes as shown by the two-dot chain line _E4 in FIG. When the plunger 37 is further rotated by operating the rack 46, the oil hole 38 is removed from the notch 40 and corresponds only to the notch 41, as indicated by the symbol in FIG. It returns to normal and the oil hole 38 opens even earlier. Therefore, even if the plunger 37 is raised using the opening/closing cam 24 having the same shape, the closing timing of the exhaust valve 3 will be further advanced, and the lift curve will become as shown by the one-dot chain line _E5 in FIG. Furthermore, between the states indicated by the symbols and the states indicated by the symbols, the opening/closing timing and opening/closing period of the valve can be adjusted steplessly.

As described above, in this embodiment, the device for adjusting the opening/closing timing and opening/closing period of the valve is provided only in the exhaust valve, but the device can be implemented in the same way for the intake valve as well. In this case, the four types of adjustment in FIG. 6 can be changed to 16 types by combination.

Furthermore, in this embodiment, by providing the drain hole 22a, the pressure accumulator 34, and the throttle 35, it operates and has the following effects. That is, when the opening/closing cam 24 rotates and the push rod 5 descends due to the elastic force of the valve spring 8 to close the valve, the lift curve changes as shown in FIG. 10, which is an enlarged view of a part of FIG.
E ₂ moves in the direction of the arrow, but at this time, if pressure accumulator 3
If the valve is not installed, the closed valve will reopen and hunting will occur as shown by the chain line _E5 in the figure.
Valve control may become unstable, leading to damage to the valve section or strong impact noise. However, in this embodiment, by providing the pressure accumulator 34 and the like and providing the piston 33 with a large diameter portion and a small diameter portion, the piston 33
The oil below the large diameter becomes a cushion, and the first
Since the piston 33 and the push rod 5 are seated gently as shown by the solid line _E6 in FIG.

[Effect of idea]

As is clear from the above explanation, according to the present invention, in an intake/exhaust valve opening/closing device for an internal combustion engine, a roller guide that supports an opening/closing cam roller that can move forward and backward, and a roller guide that can move forward and backward on the same axis as the roller guide. A plunger is interposed between the valve opening/closing push rod, pressure oil is introduced between the plunger and the push rod, and the rotation of the opening/closing cam opens and closes the intake/exhaust valves via the roller guide, plunger, pressure oil, and push rod. At the same time, by rotating the plunger integrated with the pinion that engages with the pinion by easy operation, the inflow timing and discharge timing of the pressure oil can be adjusted by the action of the inclined notch. The opening/closing timing and opening period of the intake and exhaust valves can be precisely and steplessly adjusted by simply moving the rack forward and backward during operation, improving operating efficiency and reducing labor. At the same time, the result of the adjustment is appropriate and very good combustion can be obtained that is adapted to each load.

[Brief explanation of the drawing]

Figures 1 to 3 show a conventional intake/exhaust valve opening/closing device for an internal combustion engine, and Figure 1 is a schematic configuration diagram thereof;
Figure 2 is an enlarged sectional view of the vicinity of the valve opening/closing cam, Figure 3 is a lift curve diagram of the intake valve and exhaust valve, and Figures 4 to 10 are of the intake/exhaust valve opening/closing device for an internal combustion engine according to the present invention. Fig. 4 is a cross-sectional view of the driving portion thereof, Fig. 5 is an enlarged sectional view of the vicinity of the plunger head, and Fig. 6 is a plunger head shown for explaining the relationship between the notch and the oil hole. Developed view of Figure 7 a, b
are a side view and a top view of the upper end of the plunger holding hardware,
Figures 8a and b are similarly enlarged sectional views and side views of essential parts, Figure 9 is a lift curve diagram of the intake valve and exhaust valve, and Figure 10 is a lift showing an enlarged view of the valve closing part in Figure 9. It is a curve diagram. 3...Exhaust valve, 5...Push rod, 8...Valve spring, 9
... Cylinder case, 21 ... Lower body, 22 ...
... Upper body, 24 ... Opening/closing cam, 25 ... Roller guide, 26 ... Roller, 30 ... Compression coil spring,
32... Upper barrel, 33... Piston, 36...
... lower barrel, 37 ... plunger, 38 ... oil hole, 39 ... space, 40, 41 ... notch, 4
2... Annular groove, 43, 44... Communication hole, 45...
Pinion, 46...easy.

Claims (1)

[Scope of utility model registration request] As the opening/closing cam rotates, the push rod moves forward and backward through the rollers that are in contact with the cam surface, and the suction/closing rod connected to the push rod moves forward and backward.
In an intake/exhaust valve opening/closing device for an internal combustion engine that opens and closes an exhaust valve, the roller support member and the push rod are biased toward the valve opening side by another spring member to connect the upper and lower parts of the cylinder case side body. Each of them is supported so as to be able to freely reciprocate, and an oil hole connected to a hydraulic pipe is located between the support member and the push rod and opens in the outer wall of the cylinder, and the lower end is rotatable by the support member. a plunger supported and reciprocably supported by the cylindrical body with its upper end facing near the lower part of the oil hole at its lower limit; a piston that is reciprocably supported by the cylindrical body such that a pressure oil space that communicates with the oil hole is formed between the piston and the upper end; a rack that is concentric and meshes with an integral pinion; an annular groove that communicates with the space and is formed on the outer peripheral surface of the plunger and communicates with the oil hole at the upper limit of the plunger; and a ring that communicates with the space and the annular groove. A pair of upper and lower notches that are open to the sides and formed in an arc shape along the outer circumferential surface of the plunger, and that have mutually different phases in the circumferential direction and a mutual interval that gradually changes in the circumferential direction. An intake/exhaust valve opening/closing device for an internal combustion engine, characterized in that it is provided with a notch that is inclined so as to