JPH0259287B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a valve operating system that controls the opening and closing of intake and exhaust valves. Relating to an actuation device.

(Prior art) In general, in the case of a multi-cylinder engine, when the engine has surplus power such as when idling, decelerating, or descending a slope, the intake and exhaust of specific cylinders are stopped so that the operation of some of the cylinders is stopped. It is preferable to stop the operation of the valve in order to improve fuel efficiency.

In addition, in the case of a so-called dual induction intake type engine that has two intake ports, one for low load and one for high load, when the engine is running at low load, intake air is supplied only from the low load intake port. It is possible to open and close only the low-load intake valve that opens and closes the load intake port, and to stop the operation of the high-load intake valve that opens and closes the high-load intake port, due to the intake air from the low-load intake port. Effectively creates a strong intake swirl within the combustion chamber,
It is known that this is preferable for improving combustion stability and fuel efficiency.

Conventionally, there is a mechanical type device as disclosed in Japanese Patent Publication No. 55-26285 as a device for rendering the intake and exhaust valves inactive.

The mechanical type described above includes a rocker arm operating body, a rocker arm extending between the rocker arm operating body and the valve of the internal combustion engine, and a rocker arm that swings from the rocker arm to transmit the motion of the rocker arm to the valve. and a fulcrum support device disposed intermediate both ends of the rocker arm;
a load transmission device stacked on the fulcrum and configured to be able to float together with the fulcrum in the fulcrum support device;
an intervening device that can move laterally with respect to the fulcrum support device to a position where it blocks movement of the load transfer device; and an intervening device that is movable to a position where it blocks movement of the load transfer device. The load transmitting device includes a biasing device for pushing the load transmitting device in a certain direction, and an actuating device for selectively moving the intervening device toward or away from the load transmitting device movement blocking position. When the intervening device is in a position where it prevents movement of the load transfer device, it prevents the load transfer device from floating between the fulcrum and the rocker arm, thereby fixing the swing axis of the rocker arm at a constant position and operating the valve. When the intervening device is in a position where it does not block the movement of the load transfer device, the load transfer device and the intersection point are prevented from floating on the fulcrum support device in response to the swinging of the rocker arm by the rocker arm operating body. The permitting prevents the rocker arm from transmitting movement of the rocker arm actuator to the valve, rendering the valve inoperative.

(Problem to be Solved by the Invention) However, in this type of device, the intervening device is placed at a position that prevents the movement of the load transmission device only when the cam surface of the camshaft that operates the rocker arm actuating body is on the reference circle. It is a mechanism that allows for room to advance. Therefore, the valve can only be switched from the non-operating state to the operating state when the Rocker arm operating body contacts the reference circle of the cam surface of the camshaft during one rotation of the camshaft. Since the engine is rotating at a high speed, it is difficult to perform the above switching, and there is a drawback that switching can only be performed when the engine is operating at low speed. For this reason, it has been particularly difficult to apply this method to a dual induction type high-load intake valve, which remains inactive even during low-load, high-speed operation.

The present invention has been made in view of the above problems, and it is possible to switch the valve from an inactive state to an active state without causing an increase in engine drive loss, not only when the engine is running at low speeds, but also at high speeds. The object of the present invention is to provide an engine valve deactivation device that can be operated smoothly during operation.

In addition, an object of the present invention is to provide an engine valve deactivation device in which the rigidity of a support member that swingably supports a fulcrum member is increased, and the mounting accuracy thereof is improved.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a camshaft having a cam surface, an intake or exhaust valve that is always biased in the closing direction by a spring, and the camshaft. a rocker arm that transmits the movement of the cam surface of the rocker arm to the valve; a fulcrum member that constitutes a fulcrum of the rocker arm; and a support member that is formed integrally with the cam cap of the camshaft and slidably supports the fulcrum member within the insertion hole. , an intermediate member disposed inside the fulcrum member so as to be slidable in the same direction as the sliding direction, a spring member compressed between the fulcrum member and the intermediate member, and each of the above members. A rocker arm cover forming a covered bearing and the intermediate member are positioned above the rocker arm cover, and the intermediate member is pressed toward the rocker arm side against the biasing force of the spring member to bring the intermediate member into contact with the fulcrum member. A first position in which the valve is placed in an operative state, and the valve is placed in an inoperative state by retreating in a direction away from the rocker arm in the sliding direction of the fulcrum member and separating the intermediate member from the fulcrum member by the biasing force of the spring member. a cam that takes the second position; the cam is attached to a shaft rotatably supported by a bearing formed in the rocker arm cover; rotation of the shaft causes the cam to take the first position; and a second position.

(Function) When the cam attached to the shaft is positioned at the first position by rotating the shaft that is rotatably supported by the bearing of the Rocker arm cover, the intermediate member comes into contact with the fulcrum member and the shaft is rotated. The fulcrum member is pressed against the rocker arm, whereby the rocker arm swings using the fulcrum member as a fulcrum in accordance with the movement of the cam surface of the camshaft, and the movement of the cam surface is transmitted to the valve to put the valve into an operating state.

On the other hand, when the cam is positioned at the second position by the rotation of the shaft, the intermediate member separates from the fulcrum member to make the fulcrum member floating, thereby causing the cam to move in response to the movement of the cam surface of the camshaft. The rocker arm is allowed to float with the fulcrum member, and the movement of the cam surface is not transmitted to the valve, resulting in an inoperative state.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

Figures 1 and 2 show the present invention applied to a 3-port engine with a dual induction intake system in which one cylinder is provided with two intake ports for low load and one for high load, and one exhaust port. An example of application is shown.

Reference numeral 1 denotes a cylinder head (engine fixed part), which forms a cylinder 2 constituting a combustion chamber, and this cylinder 2 has a pair of intake ports 3a and 3b for low load and high load, respectively, in parallel. Further, an exhaust port 4 is provided to open opposite the intake ports 3a and 3b. The low-load intake port 3a is formed with a relatively narrow passage area to increase the intake flow rate, and is curved so as to form a swirl of intake air within the cylinder 2. On the other hand, the high-load intake port 3b is formed to have a relatively large passage area in order to increase intake air filling efficiency. In addition, at the openings of the low-load and high-load intake ports 3a and 3b to the cylinder 2, each intake port 3a and 3b has an intake valve 5 for low-load and high-load use that opens and closes at predetermined timing, respectively.
a and 5b are arranged. On the other hand, exhaust port 4
An exhaust valve 6 that opens and closes the exhaust port 4 at a predetermined timing is disposed at the opening to the cylinder 2.
Each intake valve 5a, 5b and exhaust valve 6 are arranged in a V shape. An ignition plug 7 is provided facing approximately the upper center of the cylinder 2.

A valve operating mechanism 8 consisting of a rocker arm type overhead cam mechanism for controlling the opening and closing of the low-load and high-load intake valves 5a, 5b and the exhaust valve 6 is disposed above the cylinder head 1. The valve mechanism 8 has a single camshaft 9 extending in the direction of the centerline of the cylinder head 1 and rotationally driven by an engine crankshaft (not shown). Valve 5a, 5
b and a cam surface 9a corresponding to the exhaust valve 6 is formed. Moreover, for each valve 5a, 5b, 6,
Each valve 5 is slidably supported in a valve guide 10
A valve spring 11 that biases the valves 5a, 5b, and 6 in the valve closing direction, that is, upwardly, has one end attached to the cam surface 9a of the corresponding camshaft 9, and the other end attached to each valve 5a, 5.
A swingable rocker arm 12 that contacts the valve stems 5s, 6s of valves 5s, 6, respectively and transmits the movement of the cam surface 9a to each valve 5a, 5b, 6, and a support member 14 fixed to the cylinder head 1 are fitted. Insertion hole 1
A spherical recess 1 is fitted and held in the rocker arm 4a, 14b so as to be slidable in the vertical direction, and has a hemispherical tip 13a formed in the middle part of the rocker arm 12.
A fulcrum member 13 is provided that fits and contacts the fulcrum member 2a and constitutes a fulcrum of the rocker arm 12, and as the camshaft 9 rotates, the rocker arm 12 swings about the distal end 13a of the fulcrum member 13 as a fulcrum, thereby supporting each valve 5a. , 5b, and 6 can be opened and closed.

The insertion hole 14a of the support member 14 is on the exhaust valve 6 side and the low-load intake valve 5a side, and has a bottom at the top, while the insertion hole 14b is on the high-load intake valve 5b side.
It is on the side and penetrates vertically (see Figure 4).
Further, the support member 14 is formed integrally with each cam cap 14c constituting the bearing of the camshaft 9, and is fixed to the cylinder head 1 by a bolt 114 (see FIG. 3). Note that the support member 14 has a cam cap portion 14c and insertion holes 14a, 1 on both sides.
It has reinforcing ribs 14e that connect the cylindrical portions provided with ribs 4b. Each rocker arm 12 has protrusions 12c on both sides of the valve stems 5s, 6s in the axial direction of the camshaft 9 in order to ensure engagement at the abutting portions with the valve stems 5s, 6s.

Furthermore, on the exhaust valve 6 side of the valve mechanism 8,
A hydraulic tappet 15 is slidably disposed within the fulcrum member 13. The upper end of the hydraulic tappet 15 contacts the bottom of the insertion hole 14a, and the lower end contacts the rod portion 13b formed in the center of the fulcrum member 13 so as to protrude upward, and the spring 16
is urged upward (to the bottom side of the insertion hole 14a),
Therefore, the fulcrum member 13 is pressed toward the rocker arm 12 side with good followability by the hydraulic tappet 15, thereby preventing the occurrence of valve clearance. Furthermore, the low-load intake valve 5a side of the valve mechanism 8 is configured in the same manner as the exhaust valve 6 side with respect to the support member 14.

On the other hand, on the high-load intake valve 5b side of the valve operating mechanism 8, the sliding direction of the fulcrum member 13 is An intermediate member 17 is slidably inserted in the same direction as the spring member 1, and a spring member 1 is compressed between the intermediate member 17 and the fulcrum member 13.
8 and a cam member 19 rotatably supported on the support member 14 and abutting the intermediate member 17.

The cam member 19 presses the intermediate member 17 toward the rocker arm 12, that is, downwardly, against the biasing force of the spring member 18 in the first position, thereby bringing the intermediate member 17 into contact with the upper end of the rod portion 13b of the fulcrum member 13. A cam 20 having a first cam surface 20a and a second cam surface 20b that separates the intermediate member 17 from the fulcrum member 13 in the second position by the urging force of the spring member 18, and a shaft 21 on which the cam 20 is fitted and supported. And this shaft 21
One end is fitted onto the shaft 21 and the other end is locked into the notch 20c of the cam 20, elastically engaging the cam 20 in the pressing direction of the intermediate member 17 (counterclockwise in FIG. 1). Matching spring 22
and a pair of pins 23 and 24 fixed to the cam 20 and the shaft 21, respectively. The shaft 21, into which the cam 20 of each cylinder 2 is fitted, is rotatably supported by a bearing 121 on the upper part of the rocker arm cover 1a fixed to the cylinder head 1 (see Fig. 5a). , b).

When the shaft 21 of the cam member 19 is rotated by a drive mechanism (not shown) and positioned at the first position during high-load operation of the engine, the intermediate member 17 is attached to the first cam surface 20a of the cam member 19.
The fulcrum member 13 is pressed by the rocker arm 12, which causes the rocker arm 12 to swing about the fulcrum member 13, thereby directing the movement of the cam surface 9a of the camshaft 9 to the high-load intake valve 5.
b, and the high-load intake valve 5b is activated (see FIG. 6). When transitioning from the second position described later to the first position, the rocker arm 12 is in the raised position (see the chain line in FIG. 6) by the cam of the camshaft 9 at the beginning of the transition or during the transition, and the cam 20 of the cam member 19 When a considerable force is required to press the intermediate member 17, the rotational force transmitted from the shaft 21 to the cam 20 is absorbed by the spring 22, and the rocker arm 12 is moved to the lowered position, that is, on the reference circle of the cam surface 9a. When the cam 20 comes into contact (see the solid line in FIG. 6), the cam 20 is completely rotated to the first position. Therefore, when the rocker arm 12 comes into contact with the cam portion of the cam surface 9a during this switching, the high-load intake valve 5b opens with a lift amount smaller than the lift amount during normal operation.

On the other hand, during low load operation of the engine, the pin 23 of the cam 20 is pressed by the pin 24 of the shaft 21, and the cam 20 rotates to the second position. The intermediate member 17 and the fulcrum member 13 are separated from each other, and the fulcrum member 13 is placed in a floating state via the intermediate member 17, so that the rocker arm 12 and the fulcrum member 13 are moved in accordance with the movement of the cam surface 9a of the camshaft 9. floats, the movement of the cam surface 9b is not transmitted to the high-load intake valve 5b, and the high-load intake valve 5b is rendered inoperative, thereby configuring the valve inoperation device A according to the present invention.

Next, the structure of the intermediate member 17 will be explained in detail with reference to FIGS. 6 to 8.

The intermediate member 17 has a hydraulic tappet structure, and has a pressure receiving part 2 at the upper part that receives the pressing force from the cam member 19.
5a and a bottomed cylindrical first member 25 having a cylindrical sliding portion 25b that slides within the fulcrum member 13 on the side thereof.
The first member 25 is slidably fitted in a liquid-tight manner, and has a pressing portion 26a that contacts the rod portion 13b of the fulcrum member 13 at the bottom and a communication hole 26 at the center.
The second member 26 has a bottomed cylindrical shape and has a partition wall portion 26c provided with a pressure point b, and an oil reservoir chamber 26d is defined between the partition wall portion 26c and the bottom portion (pressing portion 26a). It consists of. An oil chamber 27 is defined by the inner surface of the first member 25 and the partition wall portion 26c of the second member 26.
A check ball 28 is provided above the partition wall 26c (on the oil chamber 27 side) at a position facing the communication hole 26b.
a and a spring 28b, the oil sump chamber 26
A check valve 28 is provided to allow oil to flow into the oil chamber 27 through the communication hole 26b. A first communication hole 13c is provided in the peripheral wall of the fulcrum member 13 at a position facing an oil passage 14d formed in the support member 14 and communicating with an oil pump (not shown), and the first communication hole 13c 2
5b is provided with a second communication hole 25c at a position facing the first communication hole 13c, and a second communication hole 25c is provided in the peripheral wall of the second member 26 at a position opposite to the second communication hole 25c.
A third communication hole 26e opening at 6d is provided. Therefore, the oil reservoir chamber 26d of the second member 26 is
The third communication hole 26e, the second communication hole 25c and the first
It communicates with the oil passage 14d through the communication hole 13c. Further, on the lower inner circumferential wall of the first member 25, a second
A retaining member 29 for retaining the member 26 is provided.

Therefore, the oil pumped by the oil pump into the oil passage 14d formed in the support member 14 flows through the first to third communication holes 13c, 25c, 26.
The oil is supplied to the oil reservoir chamber 26d through e.

When the cam member 19 is in the first position, when the intermediate member 17 separates from the fulcrum member 13, the oil reservoir chamber 26
The oil of d passes through the communication hole 26b and the check valve 28, flows into the oil chamber 27, and flows into the second member 26.
slides away from the first member 25. Thereby, the intermediate member 17 is entirely expanded, and the first
With the pressure receiving part 25a of the member 25 in contact with the first cam surface 20a of the cam 20, the pressing part 2 of the second member 26
When the rod 6a comes into contact with the upper end of the rod portion 13b of the fulcrum member 13, the pressure in the oil chamber 27 increases and the flow of oil into the oil chamber 27 is stopped. Even if the intermediate member 17 is pressed from below by the rod portion 13b of the fulcrum member 13, the oil flowing into the oil chamber 27 does not flow back into the oil reservoir chamber 26d due to the action of the check valve 28, so that the intermediate member 17 is compressed. There's nothing to do,
The intermediate member 17 reliably maintains the state of contact with the fulcrum member 13.

Furthermore, a relief hole 25d is provided in the pressure receiving part 25a of the first member 25, and a part of the pressure receiving part 25a is provided below the pressure receiving part 25a (oil chamber 27).
The relief valve is composed of a ball 30a that projects upward from 5a and can be seated in the relief hole 25d, and a spring 30b that biases the ball 30a in the seating direction, and allows oil to flow out into the oil chamber 27 when the valve is inactive. 30 are arranged. Cam member 19
In this case, when he was ranked as the first emperor, the pressure receiving part 2
A ball 30a is placed on the first cam surface 20a that contacts the ball 5a.
A recess 20 that allows the pressure receiving part 25a to protrude upward.
d is provided. As a result, when the cam member 19 is in the first position as shown in FIG. 6 (when the high-load intake valve 5b is in the operating state), the recess 20
d allows the ball 30a to protrude upward, and by keeping the relief valve 30 in the closed state and closing the relief hole 25d, the intermediate member 17 is maintained in contact with the fulcrum member 13. Functionality will be ensured.

On the other hand, as shown in FIG.
When the ball 30a is in the position (when the high-load intake valve 5b is inactive), the second cam surface 20b of the cam 20 pushes the ball 30a downward, and the relief valve 30 opens to open the relief hole 25d. is opened, the oil in the oil chamber 27 flows into the relief hole 2.
5d, and the pressure in the oil chamber 27 is relieved. That is, when the cam member 19 is in the second position, the intermediate member 17 is in the maximum extension state (the first member 25 rises due to the urging force of the spring member 18 and contacts the cam member 19, as shown in FIG. 8).
state in which the second member 26 is in contact with the retaining member 29)
However, the oil in the oil chamber 27 is leaking from the relief hole 25.
It is in a state where it can flow out via d. As a result, when the cam member 19 is switched from the second position to the first position (when the high-load intake valve 5b is switched from the non-operating state to the operating state), the intermediate member 17 is in the maximum extension state. Even if the fulcrum member 13 is brought into contact with the fulcrum member 13, it will easily contract, so if the fulcrum member 13 comes into contact with the fulcrum member 13 in its maximum extension state, the fulcrum will be lowered from its normal position and the high-load intake valve 5b will be inadvertently moved. This is to prevent the valve from opening.

In addition, in FIGS. 6 to 8, 13d, 1
3e is an oil hole provided in the fulcrum member 13 so that oil leaked into the fulcrum member 13 is supplied between the tip 13d of the fulcrum member 13 and the spherical recess 12a of the rocker arm 12; 12b is an oil hole provided in the rocker arm 12; This is an oil drain hole provided in the spherical recess 12a.

Next, the operation of the above embodiment will be explained.

During low-load operation of the engine, the cam member 19 is placed in the second position as shown in FIG. 8, whereby the valve deactivation device A is activated and the high-load intake valve 5b is rendered inactive. The high-load intake valve 5b is held in a closed state by its valve spring 11, thereby closing the high-load intake port 3b. Further, the low-load intake valve 5a is controlled to open and close by the valve operating mechanism 8 as usual. Therefore, the intake port 3a for low load
By increasing the intake flow rate and creating a strong swirl of intake air in the cylinder 2, combustion stability and combustion performance during low-load operation are improved.

On the other hand, during high-load operation of the engine, the cam member 19 takes the first position as shown in FIG. Opening and closing are controlled by the valve mechanism 8. As a result, air is taken in from the high-load intake port 3b as well as the low-load intake port 3a, and as a result, the filling efficiency of the intake air is increased and the output during high-load operation is improved.

In this way, the dual induction intake system can be obtained by activating and inactivating the high-load intake valve 5b itself using the valve deactivation device A, without providing a separate on-off valve. The structure can be simplified, and since the high-load intake valve 5b is kept inactive during low-load operation, engine drive loss can be reduced.

Further, the valve deactivation device A is a locker arm 12.
The fulcrum member 13 constituting the fulcrum of the cam member 19
By moving forward and backward in the same direction as the sliding direction of the fulcrum member 13, the fulcrum state and the floating state are directly changed via the intermediate member 17, so the high-load intake valve 5b can be activated from the inactive state. When switching to the state or vice versa, it is possible to perform the switching over multiple revolutions of the camshaft 9. Therefore, the above switching can always be carried out smoothly regardless of whether the engine is operating at low speed or high speed.

Moreover, when the high-load intake valve 5b is inactive, the intermediate member 17
According to the movement of the cam surface 9a of the
Since the fulcrum member 13, which floats together with the fulcrum member 13, does not respond by separating via the spring member 18, even if the above-mentioned hydraulic tappet structure is used as the intermediate member 17, there is no pumping effect, and therefore the engine This is advantageous in reducing driving loss.

Note that the present invention is not limited to the above-mentioned embodiments, but also includes various other modifications. That is, for example, in the above embodiment, an example was shown in which the valve deactivation device A was applied to the high-load intake valve 5b in a dual induction intake system, but the present invention also applies to the operation of a specific cylinder of a multi-cylinder engine. It is applicable when the intake and exhaust pipes are brought into an inoperable state in order to be stopped.

Further, in the above embodiment, the rocker arm 12 has one end connected to the camshaft 9 and the other end connected to the valve stem 5.
s and 6s, respectively, and swings using the intermediate part as a fulcrum, the present invention has one end as a fulcrum, the other end in contact with the valve stem, and the intermediate part in contact with the camshaft. It can also be applied to a Rocker arm system in which the arms are brought into contact with each other.

Further, in the above embodiment, the intermediate member 17 is a hydraulic tappet structure as described above, but a simple block body may also be used. However, the above-mentioned hydraulic tappet structure has better ability to maintain contact between the intermediate member 17 and the fulcrum member 13 and to follow the valve when the valve is in operation, and can suppress the valve clearance as small as possible. This is advantageous in reducing driving noise.

(Effects of the Invention) As described above, according to the present invention, the fulcrum member constituting the fulcrum of the rocker arm can be directly changed between the fulcrum state and the floating state by the cam via the intermediate member. Despite its simple structure, the valve can be smoothly switched between the operating state and the inactive state, not only during low-speed operation but also during high-speed operation, and since there is no pumping action, engine drive loss is reduced. can be reduced. In particular, since the valve is mechanically switched between the valve operating state and the valve non-operating state using the cam, the positioning operation between the first position and the second position is easy and the structure is simple.

In addition, since the support member that slidably supports the fulcrum member is formed integrally with the cam cap of the camshaft, its strength is improved in conjunction with the strength of the cam cap, and the rigidity of the support member is increased. Since the relative position between the member and the cam cap is constant, the fulcrum member, the cam, and the rocker arm can be mounted with high accuracy in terms of their positional relationship, and the mounting accuracy is improved.

[Brief explanation of drawings]

The drawings illustrate an embodiment in which the present invention is applied to a dual-induction intake system. FIG. 1 is a longitudinal sectional side view of a dual-induction intake system engine, FIG. 2 is a schematic plan view of the same, and FIG. 2 is a sectional view taken along the - line in Fig. 2, Fig. 4 is a plan view of the same with the rocker arm cover removed, Fig. 5a is a view similar to Fig. 4 with the rocker arm cover attached, and Fig. Figure 5b is a sectional view of the main part taken along the - line in Figure 5a, Figure 6 is an enlarged view of the main part of the valve deactivation device in Figure 1 in the operating state of the high-load intake valve, and Figure 7 is an enlarged view of the main part of the valve deactivation device in Figure 1. 6 is an enlarged detailed view of the intermediate member, and FIG. 8 is an enlarged detailed view of the intermediate member shown in FIG.
FIG. 1...Cylinder head, 5a, 5b...Intake valve, 6...Exhaust valve, 9...Camshaft, 9a...
... cam surface, 12 ... rocker arm, 13 ... fulcrum member, 14 ... support member, 15 ... hydraulic tappet, 17 ... intermediate member, 18 ... spring member.

Claims (1)

[Scope of Claims] 1. A camshaft having a cam surface, an intake or exhaust valve that is always biased in the closing direction by a spring, and a rocker arm that transmits the movement of the cam surface of the camshaft to the valve. a fulcrum member that constitutes a fulcrum of the rocker arm; a support member that is integrally formed with the cam cap of the camshaft and slidably supports the fulcrum member in the insertion hole; an intermediate member disposed to be slidable in the direction; a spring member compressed between the fulcrum member and the intermediate member; a rocker arm cover covering each of the members and forming a bearing; and the intermediate member. a first position located above the fulcrum member, in which the valve is activated by pressing the intermediate member toward the rocker arm against the biasing force of the spring member and bringing the intermediate member into contact with the fulcrum member; a cam that moves away from the rocker arm in the sliding direction to take a second position in which the intermediate member is separated from the fulcrum member by the biasing force of the spring member, thereby rendering the valve inactive; , the cam is attached to a shaft rotatably supported by a bearing formed in the rocker arm cover, and the cam is configured to take the first position and the second position by rotation of the shaft. Features an engine valve deactivation device.