JPS63106310A - Valve action state selector for internal combustion engine - Google Patents

Abstract

PURPOSE:To improve contact pressure to a cam and positional accuracy, by installing a device, energizing to a cam direction, and another device, regulating a stroke to the energizing direction, in a separate transmission member which transmits lift of the cam to a valve only when a pair of transmission members are connected. CONSTITUTION:A pair of suction valves 1a and 1b are opened or closed by each action of low speed cams 3a and 3b and a high speed cam 4 installed in a cam shaft 2, first and third rocker arms 5 and 7 as a first transmission member to be engaged with these cams and a second rocker arm 6 as a second transmission member. At this time, at each free end of the first transmission member, there are provided with respective tappet screws 9a and 9b coming into contact with each suction valve. On the other hand, one end of the second transmission member is made contact with a lifter 12. And, a coil spring 13 is contractedly installed between this lifter 12 and a guide hole 11a of a cylinder head 11 slidden with the lifter, while a step part 12a of the lifter is made contact with a stop ring 14 of the guide hole, regulating a stroke to an upper part of the lifter.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a switching device for changing the operating state of an intake valve or an exhaust valve in stages according to the rotational speed of an internal combustion engine.

<Prior Art> In order to supply the air-fuel mixture to the combustion chamber and discharge the combustion gas according to a predetermined cycle, the combustion chamber of a four-cycle engine has an intake valve and an exhaust valve that leak. Both of these valves are normally biased in the valve closing direction by a valve spring provided so as to surround the valve stem. Furthermore, both of these valves are forcibly pushed open against the biasing force of the valve spring mentioned above by a cam that is integrally installed on a camshaft that is connected and driven from the engine's crankshaft using a belt, pulley, etc. It is made possible to do so.

On the other hand, multiple intake valves or exhaust valves are provided for each cylinder, and during low-speed operation, one intake valve or exhaust valve is operated, and during high-speed operation, all valves are operated, and at the same time, the operation timing of these valves is adjusted according to the engine rotation. Various techniques have been proposed to improve the filling efficiency of the air-fuel mixture into the combustion chamber over a wide operating range by changing the speed according to the speed.

As such a valve operation state switching device, for example, in Japanese Patent Application Laid-Open No. 6L-19 (J11@) by the present applicant, one intake valve or one exhaust valve is connected to a camshaft that is rotationally driven in synchronization with the rotation of the engine. A low-speed cam that corresponds to the valve and has a shape suitable for low-speed operation of the engine, and a high-speed cam that has a shape that corresponds to high-speed operation of the engine are integrated, and the rocker shaft is in sliding contact with the low-speed cam, and one A 10th claw arm that can come into contact with one intake valve or exhaust valve, a 20th claw arm that comes into contact with the other intake valve or exhaust valve, and a 30th claw arm that comes into sliding contact with a high-speed cam are adjacent to each other and are at a relative angle. The first, second and thirty
A valve actuation body stop device for an internal combustion engine has been proposed in which a connecting means is provided that enables switching between a state in which a lock arm integrally connects each rocker arm and a state in which relative angular displacement of each rocker arm is allowed. . As this connecting device, a P4 structure is used in which each rocker arm is connected to each other by sliding a piston into a guide hole provided inside so as to connect each rocker arm, and by hydraulically operating this piston. It is disclosed in the same specification.

According to the same structure, the 30th cam is in contact with 1 and the high speed cam.
The claw arms are constantly given rocking motion by the cam, but only when the claw arms are connected each day do they transmit the lift of the cam in a multi-valve manner, and in the disconnected state are they simply in a floating state.

<Problems to be Solved by the Invention> However, while the first and 20th claw arms, which are in sliding contact with the low-speed cam, are always kept in sliding contact with the cam by the valve spring, the 30th claw arm is in sliding contact with the cam. When released, a separately provided lifter device is used to maintain sliding contact with the high-speed cam, and the setting of this biasing force becomes a problem. In other words, if the urging force is too small, it will not be possible to control the physical movement of the rocker arm at high speeds, and if it is too large, the friction will increase due to the pressing force, which will cause the coupling device to operate, especially in the base circle section of the cam. Therefore, it has been found that applying unnecessary biasing force in the base circle section may cause faster wear of the high-speed cam or the cam slipper of the high-speed rocker arm compared to the low-speed cam side. Ta.

In view of such disadvantages of the prior art, the main object of the present invention is to provide an improved valve operation for an internal combustion engine so as to appropriately limit and suppress the suppressive bias (j) to the cam surface against the rocker arm when the rocker arm is idle. An object of the present invention is to provide a state switching device.

<Means for Solving the Problems> According to the present invention, such an object is achieved by integrally connecting a cam that rotates synchronously with the crankshaft and has a shape set according to the operating speed range of the engine. a cam shaft, a valve installed at an intake port or an exhaust port of a combustion chamber, which is normally biased to close by a spring means and which is driven by the cam; 1st to communicate
a second transmission member inscribed in the cam;
A valve operating state switching device for an internal combustion engine, comprising a coupling device for selecting connection or non-coupling between the first and second transmission members, wherein the first transmission member is configured to switch the operating state of the coupling device. The second transmission member transmits the lift of the cam directly to the valve via the first transmission member only when the two transmission members are connected. The signal is transmitted to the valve, and it floats when disconnected.
The second transmission member is characterized in that it has a biasing means in a direction approaching the outer circumferential surface of the cam and a stroke defining means in the biasing direction. This is accomplished quickly by providing an engine valve operating state switching device.

In this way, when the second transmission member is required to be in a floating state, the stroke of the biasing means is regulated, and for example, for the base circle section of the cam, the contact pressure between the transmission member and the cam is reduced. It can be set to approximately O.

<Embodiments> Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 to 4 show a first embodiment of the present invention,
As shown in FIG. 1, the internal combustion engine main body (not shown) is provided with a pair of intake valves 1a, 1b, and these intake valves 1a, 1b are connected to one of the crankshafts (not shown).
A pair of low-speed cams 3a, 3b and a single high-speed cam 4 having an oval cross section are provided integrally with the camshaft 2 which is synchronously driven at a speed of /2, and these cams 3a, 3b, 4. 1st and 30th hook arms 5.7 as the first transmission member that engage to perform a rocking motion, and a second arm 5.7 as the second transmission member.
The opening/closing operation is performed by working with the zero tension arm 6. Further, this internal combustion engine is equipped with a pair of exhaust valves (not shown), and the above-mentioned intake valves 1a and 1b are equipped with a pair of exhaust valves (not shown).
It is driven to open and close in the same way.

The first to thirtieth hook arms 5 to 7 are rotatably supported adjacent to each other by a rocker shaft 8 fixed below the cam to 2 in parallel to the cam shaft 2. 1
The 30th hook arm 5.7 has basically the same shape, its base is pivotally supported by the rocker shaft 8, and its free end extends above both intake valves 1a, 1b.

Each intake valve 1 is provided at the free end of these double-ended hook arms 5.7.
Tappet screws 9a and 9b abutting on the upper ends of portions a and 1b are screwed so as to be movable forward and backward, respectively, and the tappet screws are prevented from loosening by lock nuts 10a and 10b.

The 20th claw arm 6 is connected to the first and 30th claw arms 5.
7 and is pivotally supported by a rocker shaft 8. This 20th
The lever arm 6 connects the rocker shaft 8 to both intake valves 1a,
1b, and as clearly shown in FIG. 2, a cam slipper 6a is formed on the upper surface of the cam slipper 6a for slidingly contacting the high-speed cam 4, and the lower surface of the end thereof is as shown in FIG.
It is in contact with the upper end surface of the lifter 12 which slides into a guide hole 11a formed in the cylinder radius 11. A coil spring 13 is compressed between the inner surface of the lifter 12 and the bottom surface of the guide hole 11a, and constantly urges the lifter 12 upward. It is configured to follow the outer circumferential surface of the cam 4 for use.

The lifter 12 has its upper part reduced in diameter, and the stepped portion 12a formed thereby abuts against the stop ring 14 fitted near the opening end of the guide hole 11a, thereby regulating the upward stroke of the lifter 12. has been done.

As shown, the camshaft 2 is rotatably supported above the engine body, and the camshaft 2 is rotatably supported above the engine body.
Low-speed cams 3a and 3b corresponding to No. 7 and high-speed cam 4 corresponding to the 20th claw arm 6 are integrally connected. As clearly shown in FIG. 3, the low-speed cams 3a and 3b have their outer peripheral surfaces attached to cam slippers 5a and 7a formed on the upper surfaces of the first and thirtieth lever arms 5.7.
It is supposed to be 1q. Note that the lifter 12 is not shown in FIG. 3.

These first to thirtieth rocker arms 5 to 7 are swung together as a unit by a connecting device 15 installed in a hole drilled through the center of each rocker arm 5 to 7 and parallel to the rocker shaft 8. It is made possible to switch between a state in which it can move 1q and a state in which it can be relatively displaced.

On the other hand, a retainer 16a is provided at the upper part of both intake valves 1a and 1b.
, 16b are provided respectively, and these retainers 1
Both intake valves 1a, 1b are installed between 6a, 16b and the engine body.
Valve springs 17a and 17b surrounding the stem portion of
is interposed to bias both valves 1a and 1b in the valve-closing direction, that is, upward in FIG. 3.

As clearly shown in FIGS. 4 and 5, the first and 30th
Guide holes 20.21 are drilled in each of the claw arms 5.7 in parallel to the rocker shaft 8, passing between both side surfaces thereof. On the inner end side of both guide holes 20 and 21,
A reduced diameter portion 22.23 is formed, and a stepped portion 24.25 is formed accordingly.

The 20th rocker arm 6 includes both the first and third rocker arms 5.
．． Guide recesses 26 corresponding to both guide holes 20 and 21 of No. 7
a and 26b are perforated on both sides, respectively.

Inside the guide holes 20 and 21 described above, there is a guide hole 2.
A piston 29.3 that slides into a small diameter portion 22.23 of 0.21 mm and has an enlarged diameter stepped portion 27.28 formed at its outer end.
0 is accepted respectively. Both pistons 29.
30 is a coil spring 31.32 compressed between the enlarged diameter step portion 27.28 and the step portion 24.25 of the guide hole 20.21.
Therefore, it is always biased in the immersion direction. Further, caps 34.35 are fitted to the outer ends of both guide holes 20.21 via stop rings 33, thereby stopping the handling of both pistons 29.30.

The axial dimensions of both screws 1-29.30 are determined so that when one end abuts the cap 34.35, it does not protrude from the end face facing the guide recesses 26a, 26b of the guide hole 20.21. There is.

The inner end sides of both caps 34.35 are reduced in diameter, so that the outer end surfaces of both pistons 29.30 and cap 34.35 are reduced in diameter.
Gaps 36 and 37 are defined between the two parts 35 and 35, respectively. Further, a passage 38 is bored in the rocker shaft 8 and communicates with a hydraulic pressure supply device (not shown), and is bored so as to communicate with the gaps 36 and 37 of the first and 30th arms 5.7, respectively. Via the provided oil passages 39a, 39b and communication holes 40a, 40b drilled in the peripheral wall of the rocker shaft 8, the operation is performed regardless of the swinging state of the first and 30th lever arms 5.7. The hydraulic oil supplied from the oil supply passage 38h1 is always kept in both the spaces 36 and 37 for 41 people.

Next, the operation of the apparatus described above will be explained.

First, referring to FIG. 4.5, in the middle and low speed range of the engine, hydraulic pressure is supplied to both guide holes 20 and 21 of the coupling device 15 by closing a control valve (not shown). First, each piston 29.30 is aligned in each guide hole 20.21 as shown in FIG. 4 by the elastic force of each coil spring 31.32, and therefore each rocker arm 5-7 can be displaced relative to each other. It is.

A series like this? ; When the mounting @15 is in the disconnected state, the first and 30th claw arms 5.7 swing in accordance with the 1° speed cams 3a and 3b due to the rotational movement of the camshaft 2. , both intake valves 1a and 1b are driven to open and close by delaying their closing timing and advancing their closing timing, and also by reducing each lift. At this time, the 20th claw arm 6 swings due to sliding contact with the high-speed cam 4, but this swinging action has no effect on the operation of both intake valves 1a and 1b.

During high-speed operation of the engine, by opening the control valve, the air gap 36 of both guide holes 20.21 of the coupling device 15 is supplied from the hydraulic oil supply passage 38 through the oil passages 39a, 39b1 and the communication holes 40a, 40b. Hydraulic pressure is supplied within .37. As a result, as shown in FIG. 5, both pistons 29, 30 move toward the 20th hook arm 6 against the biasing force of the coil springs 31, 32. As a result, the inner end portions of both pistons 29 and 30 respectively protrude into the guide recesses 26a and 26b of the 20th claw arm 6, and the first to 30th claw arms 5 to 7 are connected to each other.

As described above, when the first to thirtieth lever arms 5 to 7 are connected to each other by the coupling device 15, the 1♦ movement of the 20th lever arm 6 in sliding contact with the high-speed cam 4 is the most Due to the large size, the first and 30th arm 5
．． 7 swings together with the 20th lug arm 6. Therefore, both intake valves 1a and 1b are driven to open and close together, with their closing timings being earlier and later, and their lift amounts being smaller, according to the cam profile of the high-speed cam 4.

6 to 9 show a second embodiment of the invention.

In this embodiment, as shown in FIG. 6, the pair of intake valves 1a and 1b are composed of a pair of low-speed cams 3a and 3b having an oval cross section and a single intake valve, as in the first embodiment. Opening and closing operations are performed by the functions of one high-speed cam 4 and first to third packet lifters 55 to 57 as transmission members that engage these cams 3a, 3b, and 4 to perform linear sliding motion. ing.

The first to third packet lifters 55 to 57 are movably received adjacent to each other in a guide block 58 formed in the engine body below the camshaft 2. The first and third bucket lifters 55 and 57 have basically the same shape, and the low-speed cams 3a and 3b are in sliding contact with the upper surfaces thereof.
The upper ends of each intake valve 1a, 1b are in contact with the inner surface of the lower skirt portion.

A second bucket lifter 56 is supported within a guide block 58 between the first and third bucket lifters 55,57. The second bucket trick 56 is movable relative to the first and third packet lifters 55 and 57, and the high-speed cam 4 is in sliding contact with the upper surface of the second bucket trick 56, and the mechanism 1 to the lower part thereof is movable relative to each other. A coil spring 60 is compressed between the inner surface and a spring receiver 59 formed integrally with the engine body. As a result, the second packet lifter 56 is always urged upward and maintained in sliding contact with the high-speed cam 4.

The side wall surfaces of these first to third bucket tricks 55 to 57 that are in sliding contact with each other are ground into flat surfaces, and the mutual rotation in the circumferential direction is prevented by sliding contact between the flat surfaces (Fig. 7). .

As clearly shown in FIGS. 7 and 9, a pair of radially outward protrusions 61a and 61b are formed diagonally at the lower end of the second packet lifter 56, and are formed on the inner surface of the guide block 58. The second bucket lifter 56 is engaged with corresponding recesses 62a and 62b, thereby defining the upward stroke of the second bucket lifter 56.

Similar to the first embodiment, the camshaft 2 is rotatably supported above the engine body, and includes low-speed cams 3a, 3b corresponding to the first and third bucket lifters 55, 57, The high-speed cam 4 corresponding to the two-bucket lifter 56 is
They are integrally connected.

These first to third packet lifters 55 to 57 are connected by a connecting device 15 similar to that shown in the first embodiment described above.
It is possible to switch between a state in which it can slide into one body and a state in which it can be relatively displaced.

As best shown in FIGS. 6 and 7, the coupling device 15
has almost the same structure as the first embodiment, and is installed above each packet lifter 55-57. In the case of this embodiment, the caps 34.35 in the first embodiment are omitted, and the outer ends of both guide holes 20.21 bored in both bucket lifters 55.57 are provided in the guide block 58. Oil passages 03a and 63b formed to communicate with each other
Hydraulic pressure is applied directly to the outer end surface of the side piston 29.3Q through the piston 29.3Q.

In this embodiment, as in the first embodiment described above, the hydraulic oil acting on both the pistons 29.3Q through the oil passages 63a and 63b is interrupted, so that both screws 1 and 29.
．． The inner end of the bucket lifter 30 is the second bucket] - It enters and leaves the guide recesses 26a and 26b formed in the lifter 56, and it is possible to select whether each bucket lifter is connected or not.

In both the first and second embodiments described above, the second bucket lifter (20th lever arm) that is in sliding contact with the high-speed cam 4 is biased by the spring regardless of the biasing force of the valve spring in the uncoupled state. However, by regulating the upward stroke of the lifter as described above, it is possible to avoid applying an excessive pressing force to the high-speed cam surface.

In the above embodiment, the transmission member is divided into three parts and two valves are operated simultaneously. However, the present invention provides a valve operation state switching device configured to stop one valve at a predetermined rotational speed. Alternatively, it is equally applicable to a device that uses a two-split transmission member to change the operating timing of one valve.

<Effects of the Invention> As described above, according to the present invention, it is possible to suitably limit the contact pressure exerted by the second transmission member on the cam surface at the time of leaving work. This is effective in improving the operational reliability of the coupling device and reducing friction.

[Brief explanation of the drawing]

FIG. 1 is a top view showing a first embodiment of a valve operating state switching device according to the present invention. FIG. 2 is a sectional view taken along the line ■-■ in FIG. 1. FIG. 3 is a view taken in the direction of the ■ arrow in FIG. FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 3 during low-speed operation. FIG. 5 is a cross-sectional view similar to FIG. 4 showing the state of high-speed operation. FIG. 6 is a partially cutaway elevational view of a valve mechanism according to a second embodiment of the present invention. Figure 7 shows VI[-v■ in Figure 6 which shows high-speed operation.
It is a sectional view along a line. FIG. 8 is a view in the direction of the ■ arrow in FIG. 7. FIG. 9 is a sectional view taken along the line IX-IX in FIG.
...Low speed cam 4...High speed cam 5...10th lever arm 6
...20th Tsuka Arm 7...30th Tsuka Arm 5a
, 6a, 7a...Cam slipper 8...Rocket (/71~ 9a, 9b...Tappet screws 10a, 10b...Lock nut 11...Cylinder head '11a...Guide hole 12
...Lifter 12a...Step part 13...Coil spring 14...Stop ring 15...Connection device 16a, 16b...Retainer 17a, 17b...Valve spring 20.21...
・Guide hole 22.23... Small diameter part 24.25... Step parts 26a, 26b... Guide depression 27.28... Expanded diameter step part 29.30... Piston 3
1.32...Coil spring 33...Stop ring 34.35...Cap 3
6.37...Gap 38...Passage 39a, 39
b...Oil passages 40a, 40b-...Communication hole 55...
・First bucket lifter 56...Second bucket lifter 57...Third bucket 1-lifter 58...Guide block 59...Spring receiver 60...
Coil springs 61a, 61b--Protrusions 62a, 62b--Recesses 63a, 63b--Oil passage Patent applicant Honda Gi C1 Kogyo Co., Ltd.
Patent Attorney Yo Oshima - Figure 1! J2 Figure 4 Figure 6 j17 Figure 9 Figure 8

Claims (2)

[Claims] (1) A camshaft that rotates synchronously with the crankshaft and is made up of integrally connected cams whose shape is set according to the operating speed range of the engine, and a camshaft installed in the intake port or exhaust port of the combustion chamber, a valve that is normally biased to close by a spring means and driven to open by the cam; a first transmission member that transmits the lift of the cam while contacting the valve; and a first transmission member that is in sliding contact with the cam. 1. A valve operation state switching device for an internal combustion engine, which has two transmission members and a coupling device that selects connection or non-coupling between the first and second transmission members, the first transmission member comprising: The operating state corresponding to the operating state of the connecting device is directly transmitted to the valve, and the second transmitting member changes the lifting height of the cam to the first transmitting member only when the two transmitting members are connected. The transmission is transmitted to the valve via a transmission member, and the second transmission member moves in a direction approaching the outer circumferential surface of the cam and a stroke in the biasing direction. 1. A valve operating state switching device for an internal combustion engine, comprising: regulating means. (2) The stroke regulating means prevents the urging force of the urging means from being applied to the second transmission member when the second transmission member is in sliding contact with the inner portion of the base of the cam. The valve operation state switching device for an internal combustion engine according to claim 1, wherein the valve operating state switching device for an internal combustion engine is set to .