JPH0472967B2 - - Google Patents

Abstract

PURPOSE:To improve lubricating efficiency by changing by changing the contact position between a cam face of a cam shaft and a pressure-receiving part of a tappet on the basis of the rotation of a rotational member round a cam shaft for changing the timing of a vlave and supplying oil to the rotational member from the side of the cam shaft. CONSTITUTION:When a reciprocating shaft 18 is moved to the right by a driving unit, a rotational member 14 is oscillated round a cam shaft 9 via an oscillating shaft 17, and a vlave timing of a suction (exhaust) valve 5 is slided to the side of delay by changing the contact position between a cam face 9a and a tappet pressure-receiving part 13a in a rotational direction X of a cam shaft. An oil route 14d extended between both end faces in touch with an engine main body 1 and an oil route 14c to connect the oil route 14d through to a circular route 9d provided on the cam shaft 9 are furnished in the rotational member 14, and the circular route 9d is connected to the oil pump via a radial route and an axial route 9c.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an engine valve timing control device, and more particularly to a variable mechanism for variably controlling valve timing in accordance with engine operating conditions in a valve train that controls the opening and closing of intake and exhaust valves. It is something.

In general, it is preferable from the viewpoint of engine operating performance that the valve timing of intake and exhaust valves in an engine be variably controlled depending on the operating state of the engine.
For example, when the engine is operated at low load, it is preferable to shorten the overlap period of the intake and exhaust valves because this reduces the amount of residual exhaust gas and improves combustion stability. Furthermore, when the engine is operated at high load and low speed, by shortening the overlap period of the intake and exhaust valves, blowback of intake air can be prevented and charging efficiency can be improved.
On the other hand, when the engine is operated at high load and high speed, it is preferable to set the opening period of the intake valve to be long because this increases the filling efficiency and improves the engine output.

For this reason, various variable mechanisms for variably controlling valve timing in the valve train of an engine have been proposed. For example, Special Public Interest Publication No. 52-35819
As disclosed in the above publication, a planetary gear having a centrifugal cover is interposed between the output shaft of the engine and the camshaft to change the relative position between the output shaft of the engine and the camshaft, or a camshaft. There is a three-dimensional camshaft in which the three-dimensional camshaft is slidable.

However, all of the above-mentioned conventional devices have complicated and large-scale structures, have poor variable control response and reliability, and tend to generate large noises, and thus lack practicality.

The present invention has been made in view of the above, and effectively utilizes the existing valve mechanism to adjust the contact position between the cam surface and the pressure-receiving portion of the tappet that contacts the valve stem for a specific angular position of the camshaft. Valve timing control is equipped with a highly practical variable mechanism that has a simple structure, provides responsive and reliable variable control, and generates little noise. The purpose is to provide equipment.

In order to achieve this object, the configuration of the engine valve timing control device of the present invention is such that a rotating member having a fitting hole and rotatably supported on the camshaft so as to allow mutual rotation is inserted into the fitting hole. A tappet having a pressure receiving part that receives force from the cam surface of the camshaft and a pressing part that transmits the force from the cam surface to the valve stem is slidably inserted into the valve stem, and the rotating member is pivoted around the camshaft. The valve timing control device for an engine is configured to change valve timing by moving the camshaft, and is characterized in that the rotating member is provided with an oil passage that guides oil from an oil passage provided in the camshaft to a fitting hole. It is something to do.

Accordingly, in the present invention, by rotating the rotating member around the camshaft, the contact position between the cam surface and the pressure receiving part of the tappet for a specific angular position of the camshaft is changed around the camshaft, thereby adjusting the valve timing. It is designed to be variably controlled. Since the rotating member is rotatably supported directly on the camshaft, which is the center of rotation, oil is reliably guided to the insertion hole by the oil passage of the rotating member. This is designed to lubricate the sliding part between the insertion hole and the tapepet.

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows an embodiment in which the present invention is applied to a multi-cylinder engine. The engine body 1 is formed with a plurality of cylinders 2, 2, . ing. Two intake valves 5, 5 for opening and closing the intake ports 3, 3 at predetermined timing are disposed at the openings of each of the intake ports 3, 3 to the cylinder 2, and each exhaust port 4, 4 Two exhaust valves 6, 6 for opening and closing the exhaust ports 4, 4 at predetermined timing are disposed at the opening to the cylinder 2, and each of the intake and exhaust valves 5, 6 is provided with a valve spring 7. , 7 in the valve closing direction.

An intake valve mechanism 8a that controls the opening and closing of each intake valve 5 and an exhaust valve mechanism 8b that controls the opening and closing of each exhaust valve 6 are provided in the upper part of the engine body 1.

The intake side valve mechanism 8a has an intake side camshaft 9 that is rotatably driven by an engine crankshaft (not shown), and the intake side camshaft 9 has a cam surface 9a corresponding to the intake valve 5. The rotation of the intake camshaft 9 opens and closes the intake valve 5. on the other hand,
The exhaust side valve mechanism 8b has an exhaust side camshaft 10 which is also rotationally driven by the engine crankshaft, and a cam surface 10a corresponding to the exhaust valve 6 is formed on the exhaust side camshaft 10. The exhaust valve 6 is opened and closed by the rotation of the exhaust side camshaft 10.

The intake side valve operating mechanism 8a is provided with a first variable mechanism 11 according to the present invention that variably controls the valve timing of one of the intake valves 5, 5 in the adjacent cylinders 2, 2, respectively. The exhaust side valve operating mechanism 8b is also provided with a second variable mechanism 12 according to the present invention that variably controls the valve timing of one exhaust valve 6, 6 in the adjacent cylinders 2, 2, respectively.

These first and second variable mechanisms 11 and 12 are
As shown in an enlarged view in FIG. 2, they have the same structure. That is, the first variable mechanism 11 has a pressure receiving part (pressure receiving surface) 13a which has a hollow cylindrical shape and comes into contact with the cam surfaces 9a and 9s of the intake side camshaft 9 at its upper end surface.
and a pressing portion (pressing surface) 13 that comes into contact with the valve stems 5s, 5s of the intake valves 5, 5 at the lower end surface on the opposite side.
a tappet 1 having a cylindrical sliding portion 13c connecting the pressure receiving portion 13a and the pressing portion 13b;
3, 13, and two fitting holes 14a into which the tapepets 13, 13 are fitted and held so as to be slidable in the vertical direction.
14a, and a lower surface 14 formed in an arcuate shape corresponding to the arcuate surface 1a of the engine main body 1.
b, and is rotatably supported by the intake camshaft 9 so as to allow mutual rotation, and is capable of rotating around the intake camshaft 9.
and an operating device 15 that swings the rotating member 14 around the rotation axis of the intake camshaft 9 according to the operating state of the engine (the second variable mechanism 12 is the same as the first variable mechanism 11). “′” in the component
6s is the valve stem of the exhaust valve 6).

The pressing surface 13b of the tappet 13 is formed into a spherical shape, and the center of the spherical surface is located at the center of the spherical surface when the tappet 13 is in contact with the reference circle portion 9'a of the cam 9a.
It is set at a point where the axis of rotation of the camshaft 9 and the axis of the valve stem 5s intersect. The pressing surface 13b is formed as a part of a spherical surface in consideration of the rotation of the tappet 13, and if rotation is to be restricted, it may be formed into a circular arc surface centered on the rotation axis of the camshaft 9.

The rotating member 14 is divided into upper and lower parts at the portion supported by the intake side camshaft 9,
They are integrally connected by bolts 16, 16. The operating device 15 also includes a swing shaft 17 extending in the cylinder row direction and connected to the upper end of the rotating member 14, and a swing shaft 17 disposed perpendicular to the swing shaft 17.
The reciprocating shaft 1 is engaged with the reciprocating shaft 1 and converted into reciprocating motion, which is provided so as to be able to reciprocate in the left-right direction in FIG.
8, for example, a drive device 19 that causes the rotational movement of a motor to cause the reciprocating shaft 18 to reciprocate in the above-mentioned direction, and rotates the rotating member 14 as described above via the swinging shaft 17.
It will be equipped with. The drive device 19 receives a rotation speed signal S ₁ output from a rotation speed sensor 20 that detects the engine rotation speed, and a load signal S ₂ output from a load sensor 21 that detects the engine load, and identifies the engine. During operation, the drive device 19 is driven to move the reciprocating shaft 18 rightward in FIG. The rotating member 1 rotates in the same direction (clockwise in Fig. 1).
4 and 14 are the above × centered around the intake side camshaft 9.
rotated in the direction.

Therefore, one of the intake valves 5 is slidably supported by the valve guide 22 and biased upward, that is, in the valve closing direction, by the valve spring 7, just like a normal intake and exhaust valve, and the intake valve 5 9 rotates in the above x direction, and its cam surface 9a touches the tappet 1.
When the tappet 13 is pushed down in the insertion hole 14a by pressing the pressure receiving part 13a of the valve spring 7, the pressure receiving part 13b of the tappet 13 pushes down against the biasing force of the valve spring 7, and the intake port 3 is pushed down.
open. On the other hand, when the rotating member 14 is rotated in the x direction as described above, the tappets 13, 13 also move together with the rotating member 14, and the cam surfaces 9a, 9a and the tappet receiving pressure for a specific angular position of the intake side camshaft 9 are The contact position of the portions 13a, 13a changes to the lag side with respect to the rotational direction x of the intake side camshaft 9, and the valve timing of each intake valve 5, 5 is shifted to the lag side. The above operation is similarly performed for one exhaust valve 6 by the second variable mechanism 12. Although not shown, each cylinder 2
The other intake valve 5 and the other exhaust valve 6 in
As usual, the opening and closing of the valve mechanisms 8a and 8b are controlled at fixed valve timings.

As a feature of the present invention, as shown in FIGS. 2 and 3, an oil passage 9c similar to that provided in a normal camshaft is provided in the center of the intake camshaft 9 for an oil pump ( (not shown). Also,
An annular oil passage 9d is carved on the outer peripheral surface of the rotating member support portion 9b of the intake side camshaft 9, and the oil passage 9d communicates with the oil passage 9c via an oil passage 9e extending in the radial direction. ing. Further, an oil passage 9f extending in the radial direction and opening at the cam surface 9a is communicated with the oil passage 9c. Lubricating oil is introduced between and lubricates. Also,
Lubricating oil is introduced to the camshaft bearing portion and the like through another oil passage (not shown) to lubricate the camshaft bearing portion and the like. The oil supply passage on the exhaust side is also configured in the same way as the intake side, and the exhaust side camshaft 1
0 includes oil passages 10c, 10d, 10e, 1 corresponding to each oil passage of the intake valve side camshaft 9.
0f is provided.

On the other hand, the rotating members 14, 14' have oil passages 14c, 1 facing the annular oil passage 9d.
4'c, and oil passages 14d, 14'd communicating with the oil passages 14c, 14'c and extending in the juxtaposed direction of the fitting holes 14a, 14a, 14'a, 14'a,
Oil passages 14e, 14e, 14'e, 1 communicate with these oil passages 14d, 14'd and open on the inner peripheral walls of the fitting holes 14a, 14a, 14'a, 14'a.
4'e is drilled. Oil passage 14d, 1
Both ends of 4'd are closed with blind plugs 22.
The oil passages 14e, 14'e are connected to the rotating member 1
4, 14', the cam force from the cam surfaces 9a, 10a is applied to the valve stem 5 via the tappets 13, 13' in the sliding direction of the tappets 13, 13'.
Direction of acting force transmitted to s, 6s (tapepet 1
3, 13' and the contact point of valve stem 5s, 6s)
on the opposite side to the direction in which the tappet 13,
The fitting holes 14a, 14' are located on the side opposite to the lateral force applied to the tappets 13, 13' by the reaction force of the springs 7, 7 when the sliding direction of the valves 13' and the moving direction of the valves 5, 6 deviate. It is formed to open at a. Therefore, the above camshafts 9 and 10
The oil from the oil passages 9c, 10c flows through the oil passages 9e, 10e, 9d, 10d, 14c, 1.
4'c, 14d, 14'd, 14e, 14'e through the fitting holes 14a, 1 of the rotating members 14, 14'.
4'a, in particular the fitting holes 14a, 14' are guided to the side opposite to the lateral force acting on the tappets 13, 13'.
It is configured to lubricate between the tappet a and the tappets 13, 13. Here, the oil passage 14
e and 14'e indicate that the direction of the acting force line is the rotational direction of the rotating members 14 and 14' with respect to the tapepet sliding direction during a specific operation by the operation of the operating devices 15 and 15'.
Since it is set to be shifted to the trailing side (right side in FIG. 1) of the rotating member 14, it is provided on the leading side (left side in FIG. 1) in the rotation direction x of the rotating member 14.

Furthermore, an oil hole 13e communicating with the internal cavity 13d of the tappet 13 is formed in the center of the pressure receiving part 13a of the tappet 13 so as to coincide with the oil passage 9f.
For example, two oil holes 13f, 13f communicating with the internal cavity 13d are formed near the outer periphery of b, avoiding the area in which they come into sliding contact with the valve stem 5s of the intake valve 5, and are connected to the cam surface 9a and the tappet receiving pressure. After the lubricating oil that has lubricated the gap between the tappet 13a and the tappet 13a flows into the internal cavity 13d of the tapepet 13 from the oil hole 13e,
is guided from the tappet pressing part 13b (pressing surface),
The space between the pressing portion 13b and the valve stem 5s of the intake valve 5 is lubricated. The lubricating oil supply system to the exhaust side tappet 13' is constructed in the same way as the intake side, and the exhaust side tappet 13'
Oil holes 13'e and 13'f corresponding to the oil holes of the intake tappet 13 are provided in the intake tappet 13.

Next, the operation of the apparatus of the above embodiment will be explained. During normal operation of the engine, the first and second
The variable mechanisms 11 and 12 are in a non-operating state, and the intake valve 5 and exhaust valve 6 of each cylinder 2 are controlled to open and close at predetermined valve timings by the intake side and exhaust side valve mechanisms 8a and 8b, respectively. On the other hand, during a specific operation of the engine (for example, during high load and high rotation), the first and second variable mechanisms 11 and 12 operate together, and the valve timing of one intake valve 5 in each cylinder 2 is controlled by the first variable mechanism. 11, and the valve timing of one exhaust valve 6 is controlled to be delayed by a second variable mechanism 12. As a result, the opening period of the intake valves 5, 5 is extended to the lag side where the inertial action of the intake air is large, and the total opening period of the exhaust valves 6, 6 is lengthened, thereby improving the filling efficiency of the intake air. At the same time, scavenging efficiency is improved and output performance is improved.

In this way, each of the variable mechanisms 11 and 12 has rotating members 14 and 14' that fit and hold the tappets 13 and 13' in a general valve mechanism (direct drive type overhead cam mechanism), and the rotating members 14 and 14', Member 14,1
4' around the camshafts 9 and 10, the structure is simple, easy to manufacture, and inexpensive.

Moreover, the variable control of the variable mechanisms 11, 12 is performed by controlling the cam surfaces 9a, 10a, the tapepet pressure receiving portion 13a,
Since the contact position with 13'a is changed around the camshafts 9 and 10, variable control can be performed stably with good responsiveness and reliability.

The rotating members 14, 14' are directly supported by the camshafts 9, 10 so as to allow mutual rotation, and the camshafts 9, 10, which are the supporting members,
10, the oil pumped from the oil pump to the oil passages 9c, 10c of the camshafts 9, 10 is transferred from the oil pump to the oil passages 9c, 10c of the camshafts 9, 10 at the supporting portions of the rotating members 14, 14'. 9, 10 oil passages 9d, 10
Rotating members 14, 1 via d, 9e, 10e
4' can be easily and reliably guided to the oil passages 14c, 14'c, and then the rotating members 14, 1
4' oil passages 14d, 14'd, 14e, 1
4'e to the insertion holes 14a, 14'a,
The fitting holes 14a, 14'a and the tappets 13,1
It is possible to lubricate between the sliding parts 13c and 13'c of 3', and the fitting hole 14 can be
A, 14'a and the tapepets 13, 13' can slide smoothly.

It should be noted that the present invention is not limited to the above-mentioned embodiments, but also includes various other modifications. For example, FIG. 4 shows the tappets 13, 1 in FIG.
FIG. 3 is a sectional view showing a structure in which a hydraulic tappet 33 is used instead of the hydraulic tappet 3'. As shown in FIG. 4, the hydraulic tappet 33 is connected to the pressure receiving section 13 described above.
a first member 34 having a cylindrical shape with a bottom and a sliding portion 13c; a second member 35 having a partition plate provided with a communication hole 35a in the center;
and a third member 36 in the shape of a cylinder with a bottom, which is slidable liquid-tightly with respect to the first member 34 and whose bottom plate serves as the pressing portion (pressing surface) 13b. The second member 35 and the third
A spring 37 is compressed between the member 36 and
The spring 37 causes the second member 35 to press the pressing portion 1
It is pressed into contact with the back surface of 3a. Further, below the partition plate of the second member 35 (that is, on the third member 36 side), there is a check valve 38 consisting of a check ball that can be seated in the communication hole 35a and a spring that biases the check ball toward the communication hole 35a. It is arranged. The peripheral wall forming the sliding portion 13c of the first member 34 has an oil passage 9 connected to the oil passage 9c.
A first communication hole 34a is provided at a position opposite to the oil passage 14e that communicates with the oil passage 14e and opens into the fitting hole 14a through the holes 14c and 14d. A second communication hole 34b is provided in a part of the contacting portion. Therefore, the inside of the second member 35 and the first member 3
The oil reservoir chamber 39 defined by the back surface of the pressure receiving part 13a of No. 4 is connected to the second communication hole 34b and the second member 35.
The space 35c between the first member 34 and the peripheral wall of the first member 34 communicates with the oil passage 14e cut in the rotating member 14 through the first communication hole 34a. Therefore, the lubricating oil pumped into the oil passage 9c by the oil pump lubricates between the cam surface 9a and the pressure receiving part 13a of the hydraulic tappet 33 as described above, and also flows into the oil reservoir chamber via the oil passage 14e. 39
is pumped to. When valve clearance occurs,
Oil in the oil reservoir chamber 39 passes through the communication hole 35a and the check valve 38, and flows into the hydraulic chamber 40 defined by the second member 35 and the third member 36, and the third member 36 is connected to the first member 34. Slide away from the As a result, the hydraulic tappet 33 is expanded as a whole, and the pressing part 13b of the third member 36 comes into contact with the upper end of the valve stem 5s, and when the pressure receiving part 13a of the first member 34 comes into contact with the cam surface 9a, the hydraulic pressure chamber 40
The pressure increases and the flow of oil into the hydraulic chamber 40 is stopped. The oil that has flowed into the hydraulic chamber 40 is transferred to the hydraulic tappet 33 between the cam surface 9a and the valve stem 5s.
Therefore, even if pressure is applied from above and below, the check valve 38 prevents the oil from flowing back into the reservoir chamber 39, so the hydraulic tappet 33 does not contract, and the hydraulic tappet 33 ensures that the movement of the camshaft 9 is controlled by the valve stem. 5s.

In this case, the oil passages 14c, 14d, 14e of the rotating member 14 are connected to the hydraulic tappet 3.
3 of the first member 34, especially the tapepet 33.
It is also formed to guide oil to the side opposite to the lateral force applied to it, and is designed to lubricate the space between the hydraulic tappet 33 and the insertion hole 14a, thereby smoothing the sliding movement between the two. There is.

In addition, in the above embodiment, two intake ports 3 and 2 are provided.
Although an example of application to a four-valve multi-cylinder engine having two exhaust ports 4 has been shown, it is applicable to various types of single-cylinder or multi-cylinder engines, such as a two-valve type each having one intake port and one exhaust port. is also applicable.

As explained in detail above, the engine valve timing control device of the present invention is capable of reliably variable control of engine valve timing with good responsiveness and reliability even though it has a simple structure. This will greatly contribute to ease of implementation. Moreover, the rotary member is supported on the camshaft so as to allow mutual rotation, and oil is guided from the oil passage of the camshaft to the fitting hole of the rotary member into which the tappet is inserted and held through the supporting portion. Even with a simple structure, oil can be reliably guided between the tappet and the fitting hole, and the sliding movement between the two can be facilitated.

[Brief explanation of drawings]

Fig. 1 is a vertical sectional view showing an embodiment in which the present invention is applied to a multi-cylinder engine, Fig. 2 is an enlarged perspective view of the variable mechanism portion of the embodiment of Fig. 1, and Fig. 3 is a section around the tappet of Fig. 1. FIG. 4 is an enlarged longitudinal cross-sectional view showing a modified example, and FIG. 4 is a view corresponding to FIG. 3 showing a modification. 5...Intake valve, 5s...Valve stem, 6...
Exhaust valve, 9, 10...Camshaft, 9a, 10
a...Cam surface, 9c, 9d, 9e, 10c, 10
d, 10e... Oil passage, 11... First variable mechanism, 12... Second variable mechanism, 13, 13', 33
... Tappet, 13a, 13'a... Tappet pressure receiving part, 13b, 13'b... Tappet pressing part, 1
4, 14'... Rotating member, 14a, 14'a... Fitting hole, 14c, 14d, 14e, 14'c, 1
4'd, 14'e...Oil passage, 15, 15'...
...Operating device.

Claims (1)

[Claims] 1. A tappet having a pressure receiving part that receives force from the cam surface of the camshaft and a pressing part that transmits the force from the cam surface to the valve stem, and a fitting hole into which the tappet is slidably inserted; A valve timing control device for an engine, comprising a rotating member rotatably supported to allow mutual rotation, and the rotating member is swung around a camshaft to change valve timing. A valve timing control device for an engine, wherein the rotating member is provided with an oil passage that guides oil from an oil passage provided in the camshaft to the fitting hole.