JPH045410A - Valve system of engine - Google Patents

Abstract

PURPOSE:To improve workability and durability of a valve by providing a rocker arm connecting and driving means which locks relative displacement between respective rocker arms, and a follower connecting and driving means which locks relative displacement between respective movable followers. CONSTITUTION:A pin 31 is provided as a rocker arm connecting and driving means which can lock relative displacement between a rocker arm 1 and a rocker arm 2. Pins 21 and 22 are provided as a follower connecting and driving means which can lock relative displacement of a movable follower 5 to the rocker arm 2 according to a running state of an engine. By providing movable followers which can move relatively to the rocker arms, it is possible to minimize the number of cam followers which come in slidable contact with respective cams, and to secure sufficient width of the respective cam followers. Thus, workability and durability of valves can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an engine valve operating device, and particularly to one that switches lift characteristics of a plurality of valves independently of each other.

(Conventional technology) In order to achieve both torque during low-to-medium speed operation and improved output during high-speed operation, the lift characteristics of the intake valve or exhaust valve have been varied depending on the operating condition, and this has been used to improve the intake and exhaust timing. Alternatively, it is known to control the amount of intake and exhaust (
For example, JP-A-62-121812, 63-167
(See Publication No. 016, JP-A-63-57805, etc.)
.

To explain this, one cylinder is equipped with two intake or exhaust valves, two main rocker arms whose swinging tips abut against the valves, and valves adjacent to each other between the main port and seven rocker arms. One sub-rocker arm that has no contact area with the main rocker arm is swingably supported by a common rocker shaft, and each main rocker arm has a low-speed cam.
High-speed cams having a profile with a larger valve opening angle or valve lift amount than the low-speed cams are in sliding contact with the sub-rocker arms, respectively.

At the swinging part a predetermined distance away from the rocker shaft, three rocker arms are opened in a direction parallel to the shaft by fitting a coupling pin that responds to the hydraulic pressure into or out of the fitting hole. They are coupled or uncoupled, and the response lift characteristic is switched between two stages depending on the engine operating state.

(Problem to be Solved by the Invention) However, in such a conventional device, one sub-rocker arm is provided side by side between two main rocker arms, so it is difficult to sill.

Due to the limited space on the board, the width of the cam follower that slides on each cam is restricted, making it difficult to ensure sufficient operability and durability.

The present invention has focused on such conventional problems, and an object thereof is to provide a valve operating device that can switch the lift characteristics of a plurality of valves independently of each other.

(Means for Solving the Problems) The present invention provides a valve operating device for an engine that includes a plurality of valves provided in one cylinder and having the same function, a plurality of cams having mutually different profiles, and a driven valve for each cam. A plurality of slotted openings/car arms, a rocker arm connecting drive means for locking the relative displacement of each rocker arm according to engine operating conditions, and a cam with a relatively large profile A movable follower is mounted between the rocker arm and the rocker arm and is pressed against the cam by the biasing force of a lost motion spring, and a follower connection drive means that locks the relative displacement of the movable follower with respect to the rocker arm depending on the engine operating state. .

(Function) In the operating state in which each rocker arm is operated as a unit via the rocker arm connection drive means, each opening/car arm is relatively While the response valve is driven to open and close by following a cam with a small profile, each rocker arm is driven by a cam with a relatively large profile through the movable follower because the movable follower is coupled to the rocker arm via the follower connection drive means. The response valves are driven to open and close, and the lift characteristics of the response valves can be switched in synchronization with each other depending on the engine operating state.

When each mouth/car arm is separated so as to be able to move relative to each other via the rocker arm connecting means, and the movable follower is separated so as to be able to be moved relative to the rocker arm, the movable follower expands and contracts the lost motion spring. By following the cam, the valve opening/closing operation by the rocker arm equipped with this movable follower is stopped.
The remaining rocker arm is driven by a cam with a relatively small profile to open and close the valves, and the number of valves to be opened and closed in one cylinder can be switched depending on the engine operating condition.

By providing a movable 7-way arm that can be displaced relative to the rocker arm, the number of cam followers that come into sliding contact with each cam can be minimized, making it possible to secure a sufficient width for each cam follower, improving operability and Increases durability.

(Example) Fig. 1 shows an example of an engine equipped with 62 valves (intake valves or exhaust valves may be used; the one shown is an intake valve) having the same function for one cylinder. This shows an example in which the present invention is applied.

To explain this, each cylinder is provided with two rocker arms 1.2 adjacent to each other corresponding to two intake valves 9. The base end of each rocker arm 1.2 is swingably supported by the cylinder via a rocker shaft 3 common to each cylinder, and the top of the stem of each intake valve 9 abuts the tip of each rocker arm 1.2. Valve follower part IA, 2A
are formed respectively. In the figure, 10 is a retainer that receives a valve spring that biases each intake valve 9 in the valve closing direction.

As shown in FIG. 2, the rocker arm 1 is integrally formed with a fixed follower 4 raised in an arcuate shape, and a low-speed cam that can slide into contact with the fixed follower 4 is provided.

In addition, as shown in FIG. 4, it is also possible to apply a structure in which a roller follower 37, which is freely movable with respect to a low-speed cam, is pivotally supported via a shaft 38 to the rotor arm l.

As also shown in FIG. 3, a movable follower 5 is provided on the rocker arm 2 so as to be relatively displaceable. The rocker arm 2 is formed with a guide hole 11 into which the movable follower 5 is slidably inserted.

The movable follower 5 has a cam opening 7 portion 5A formed in an arcuate shape at its upper end, which slides into contact with a high-speed cam (not shown).

A lost motion spring 6 is interposed between the lower end of the movable follower 5 and the rocker arm 2, and the urging force of the lost motion spring 6 causes the cam 7-year-old lower portion 5A to move inside the guide hole 11 while being pressed against the high-speed cam. Sliding. Note that the spring load of the lost motion spring 6 is set smaller than that of the valve spring.

Bins 21 and 22, which can be inserted between the movable follower 5 and the rocker arm 2, are provided as follower connection drive means that locks the relative displacement of the movable follower 5 with respect to the rocker arm 2 depending on the engine operating state. Follower 5
Holes are formed in which the bins 21 and 22 are slidably inserted, and the rocker arm 2 has holes in which the bins 21 and 22 are slidably inserted.
Two holes into which the movable wheels 3 are slidably inserted are formed between the movable wheels 5, an oil chamber 24 is defined behind the bottle 22, and a return spring 25 is interposed behind the bottle 23. be done.

The bins 21, 22, 23 are formed to have the same diameter and are arranged coaxially with each other within the angular range where the movable follower 5 slides into contact with the base circle portion of the cam. Oil chamber 2
4 causes the pins 21, 22 to fit over the rocker arm 2 and the movable follower 5, respectively, thereby restraining the rocker arm 2 and the movable follower 5 from each other.

On the other hand, when the bottle 22 is in contact with one end of the hole due to the biasing force of the return spring 23, each bottle 21°22.23
are accommodated in each equation, so that the movable follower 5 and the mouth/car arm 2 are not restrained.

An air vent hole 27 is formed in the rocker arm 2 and communicates with a hole into which the bottle 23 is inserted.

An oil passage 26 that guides the hydraulic pressure to the oil chamber 24 is connected to the rocker arm 2.
and is provided through the inside of the rocker shaft 3.

A pin 31 that can be inserted between each rocker arm 1.2 is provided as a rocker arm connection drive means that can lock the relative displacement of the rocker arm 1 and the rocker arm 2,
The rocker arm 1 is formed with a hole into which the bottle 31 is slidably inserted, and the rocker arm 2 is formed with a hole into which the bottle 31 is slidably inserted.
2 are slidably inserted into the holes, an oil chamber 33 is defined behind the bottle 31, and a return spring 34 is installed behind the bottle 32.

The bins 31, 32 are formed to have the same diameter and are aligned coaxially with each other with each rocker arm 1, 2 abutting each intake valve 9 in the closed position. The bottle 31 is moved by the hydraulic pressure guided to the oil chamber 33 from both ends of the arm 1,
2, each rocker arm 1,
2 are bound to each other. On the other hand, the return spring 34
When the bins 31 are in contact with one end of the holes due to the biasing force, each of the bins S1 and 32 is accommodated in each hole, so that each rocker arm 1.2 is not restrained.

An air vent hole 35 is formed in the rocker arm 2 and communicates with a hole into which the bottle 32 is inserted.

The oil passage 36 that guides the hydraulic pressure to the oil chamber 33 is connected to the rocker arm 1.
and is provided through the inside of the rocker shaft 3.

The discharge oil pressure of the oil pump is guided to each oil passage 26, 36 via a switching valve (not shown) under a predetermined engine operating condition. The Funtrol unit that electronically controls the operation of each switching valve is an engine rotation signal, a cooling water temperature signal, a lubricating oil temperature signal, an intake supercharging pressure signal from a supercharger, and a slot 7
) Inputs the valve opening signal, etc., and uses these detected values to suppress sudden fluctuations in engine torque while smoothly switching between the low-speed cam and high-speed cam and the valve body stop operation, which will be described later. It looks like this.

After the hydraulic pressure of the oil passage 36 is increased, the hydraulic pressure of the oil passage 26 is increased, and each rocker arm 1
．． 2 are mutually restrained, the movable follower 5 is smoothly restrained.

Low-speed cam and movable follower 5 slidingly in contact with fixed follower 4
The high-speed cams that come into sliding contact with the engine are each integrally formed on a common camshaft, and are driven to rotate in synchronization with the engine. Low-speed cams have different profiles (similar shapes with different sizes) to satisfy the valve speed characteristics required at low engine speeds, and high-speed cams have different profiles to satisfy the valve speed characteristics required at high engine speeds. (including shape).

In other words, the high speed cam has a profile that increases at least one of the valve opening amount and the valve opening period compared to the low speed cam. Here, both the valve lift amount and the valve opening period are increased.

Next, this movement will be explained.

When operating the engine at low load (low speed), the oil passage 26°36
The working oil pressure guided to the bins 21, 22, and 23 are both lowered and held in the unrestricted position by the biasing force of the bin 31 or the return spring 34, and the double-end hook arms 1 and 2 swing independently of each other, and the bins 21, 22, and 23 turn spring 25
The movable follower 5 is held in the unrestricted position by the biasing force of the movable follower 5 and freely reciprocates within the guide hole 11.

As a result, the rocker arm 1 drives one intake valve 9 to open and close according to the profile of the low-speed cam that slides on the fixed follower 4, whereas in the rocker arm 2, the movable follower 5 slides on and follows the high-speed cam. The movable follower 5 reciprocates within the guide hole 11 while expanding and contracting the lost motion spring 6, without swinging the rocker arm 2, and the other intake valve 9 is held in the closed position by the biasing force of the valve spring. . Therefore 2
The opening/closing operation of one of the two intake valves 9 is suspended, and only the remaining intake valve 9 is opened/closed to introduce intake air, thereby reducing fuel consumption during idling and the like.

When operating the engine at medium load (medium speed), the hydraulic pressure is oil passage 3.
6 to the oil chamber 33, the double-ended hook arm 1.
The bottle 31 is inserted across 2, with both mouths and the cap arms 1 and 2.
swings together to open and close the two intake valves 9 according to the profile of the low-speed cam that slides on the fixed follower 4. At this time, although the movable follower 5 slides into contact with and follows the high-speed cam, each of the bins 21, 22, and 23 is housed in the non-restricted position in each hole due to the biasing force of the return spring 25, so the movable follower 5 It is free to reciprocate within the idle hole 11 and does not impede the movement of each rocker arm 1.2.

When the engine is operating at high load (high speed), the hydraulic pressure is in oil passage 2.
6 into the oil chamber 24, each bottle 21, 22 .
23 moves against the return spring 25, and the bottle 2
1.22 is fitted across the double-ended hook arms 1 and 2, so that each rocker arm 1.2 and the movable follower 5 swing together. Here, since the high-speed cam is formed so that both the valve opening angle and the lift amount are larger than the low-speed cam, each intake valve 9 is driven to open and close according to the 70 fill of the high-speed cam. , the fixed follower 4 of the rocker arm 1 lifts up from the low-speed cam, and both the opening angle and lift amount of the valve become large.

Then, when the engine shifts from the high load region to the medium load region again, the operating oil pressure led to the oil chamber 24 by the operation of the switching valve decreases, and the biasing force of the return spring 25 causes each bottle 2
1, 22, and 23 move to their original unrestricted positions, and the movable follower 5 is unrestrained. Furthermore, when the engine moves from a medium load area to a low load area, the oil chamber 33
The hydraulic pressure guided to the return spring 34 decreases, and the return spring 34
The urging force causes each bottle 31, 32 to move to its original unrestricted position, and the restraint of the double-ended hook arms 1 and 2 is released.

In addition, when switching from a state in which the opening/closing operation of one intake valve 9 is suspended to a state in which both intake valves 9 are driven to open/close by high-speed cams, the bins 31 are slid to restrain each rocker arm 1 and 2 from each other. After this, the movable follower 5 is restrained to the rocker arm 2 by sliding the pins 21,22. As a result, the movable follower 5 is reciprocating greatly with respect to the rocker arm 2 which is in the valve closing position, and the bin 21.
2 is prevented from being inserted between the two, and smooth operability is ensured.

Movable follower 5 that can be displaced relative to the kick arm 2
(From this, each cam 7t slides into contact with each other once.)
The number of lowers can be minimized, and in this case, it is possible to secure a sufficient width for each cam follower 4, 5, and operability and durability can be improved.

(Effects of the Invention) The present invention includes a plurality of valves provided in one cylinder and having the same function, a plurality of rocker arms that open and close the response valves according to each cam having a different profile from each other,
A rocker arm connection drive means that locks the relative displacement of each rocker arm according to the engine operating state, and a movable member that is separated between a cam with a relatively large profile and the rocker arm and is pressed against the cam by the biasing force of a cost motion spring. By providing a follower and a follower connection drive means that locks the relative displacement of the movable follower with respect to the rocker arm depending on the engine operating condition, the number of cam followers that come into sliding contact with each cam can be minimized, and the width of each cam follower can be kept sufficiently wide. In addition, by stopping one valve according to the engine operating conditions and switching the 1-no-7 characteristic of the two valves in synchronization with each other, it is possible to improve operability and durability. 8 Power and fuel efficiency can both be improved.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a valve train showing an embodiment of the present invention, and FIGS. 2 and 3 are cross-sectional views, respectively. FIG. 4 is a cross-sectional view showing another embodiment. 1.2...Rocker arm, 3...Rocker shaft,
4... Fixed follower, 5... Movable follower, 6...
・Lost moshimin spring, 21. 22... bottle, 25... return spring, 26... oil passage,
31...Bin, 34...Return spring, 36
...Oil passage. 4 Fig. 2 1.2 - Single mouth 9 arm 3 - Rocker shaft 4 - Fixed follower 5 - Movable follower 6 - - 1 Lost soup stock 21.22.3
1--Bish 25.34--Returns Link Pa 26.36-
−・ Woyui Ketao

Claims (1)

[Claims] a plurality of valves provided in one cylinder and having the same function;
A plurality of cams having different profiles from each other, a plurality of rocker arms that are driven by each cam to open and close each valve, and a rocker arm connection drive means that locks the relative displacement of each rocker arm depending on the engine operating state. and,
A movable follower that is interposed between a cam with a relatively large profile and a rocker arm and is pressed against the cam by the biasing force of a lost motion spring, and a follower connection that locks relative displacement of the movable follower with respect to the rocker arm depending on the engine operating state. A valve actuation device for an engine, characterized in that it is provided with a driving means.