JPS6119913A - Varying valve device - Google Patents

Abstract

PURPOSE:To prevent rotation and dislocation of a timing mechanism, by a method wherein a guide member positioned in the direction of a cam shaft is mounted to a timing mechanism which determines a timing, at which an opening and a closing timing and a lift amount are shifted, through movement in the direction of the axis of the cam. CONSTITUTION:A cam piece 3, having plural cams, is moved in the direction of the axis of a cam shaft 2 by means of a plunger 27 and a driving member 26 of a timing mechanism 20 to control the opening and closing and the lift amount of a valve 11. A guide member 45 located in the direction of the direction of a cam shaft is positioned to the side of a timing mechanism 20, and rotation of the cam causes prevention of rotation of the timing mechanism 20. This prevents a brim 8 of a cam piece 3 from being dislocated from the timing mechanism 20, and enables reliable shifting of motion of a valve.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a variable valve device that switches cams for opening and closing intake and exhaust valves in accordance with engine operating conditions.

BACKGROUND ART As is well known in the art, internal combustion engines can reduce fuel consumption and greatly improve driving performance by switching the opening/closing timing and lift amount of intake and exhaust valves according to operating conditions. As a means for switching the opening/closing timing and lift amount, it is known to have two types of cams for controlling the opening and closing of the intake and exhaust valves, for example, one for high speed and one for low speed. Conventional variable valve devices that selectively switch these cams are constructed by connecting a timing mechanism supported reciprocally along a fixed member to a cam piece on which these cams are formed. The cams are switched by the reciprocating motion of this timing mechanism (Utility Model No. 57-11590
Publication No. 7, Japanese Utility Model Publication No. 168710/1983, Japanese Patent Application Publication No. 1977-168710
Publication No. 9-51114).

Problems to be Solved by the Invention Due to the rotation of the camshaft to which the above-mentioned cam piece is fitted, the timing mechanism itself may also undergo rotational displacement. Therefore, due to the structure of the timing mechanism, the connecting portion of the cam piece to the cam piece may be rotated. There is a risk of it coming off. When the connecting portion comes off from the cam piece in this way, the timing mechanism can no longer be moved and the cam cannot be switched.

Means for Solving the Problems In order to solve the above-mentioned problems, the variable valve device according to the present invention includes a guide that can be engaged with the connecting portion of the timing mechanism along the moving direction of the connecting portion with the cam piece. A member is provided.

Example The present invention will be explained below with reference to illustrated embodiments.

In FIGS. 1 and 2, a cam piece 3 is fitted into a bearing portion 2 integrally formed with a camshaft 1. As shown in FIG. In this fitting configuration, as shown in FIG.
A plurality of ridges 3a are formed at equal intervals on the inner periphery of the cam piece 3, and each ridge 2a of the bearing 2 is located between each ridge 3a of the cam piece 3. Assume that a steel ball 4 is inserted between each side. Therefore, the cam piece 3 is movable in the axial direction with respect to the camshaft 1, but rotates together with the camshaft 1 around the axis. The cam piece 3 has a first cam 5 for low-speed rotation, a second cam 6 for high-speed rotation, and a flange-like member 8 that constantly engages with a timing mechanism 20, which will be described later. Either one of the first and second cams 5.6 engages with a cam follower 10 formed on the rocker arm 9 to control the opening and closing of the valve 11. The rocker arm 9 is rotatably supported by a rocker shaft 12, and a valve clearance adjustment bolt 14 is attached to the swinging portion of the rocker arm 9 via a lock nut 13. The mouth of this bolt 14, the protruding end 14a from the car arm 9, is
Valve +1 (7) is in contact with the iliJt section. The valve 11 is always urged upward by a valve spring 16 fitted to the head or provided between the retainer 15 and the cylinder block (not shown) so as to close the intake and exhaust boats.

In the illustrated state, the first cam 5 controls the opening and closing of the valve 11, and when the camshaft 1 rotates in the direction of arrow A (FIG. 1) and the protrusion of the first cam 5 engages with the cam follower 10. , the rocker arm 9 pushes down the valve 11 against the pulp spring 16 to open the valve 11.

A timing mechanism 20 is provided near the camshaft 1 and is capable of fixing the cam piece 3 in a fixed position. The timing mechanism 20 has a cylindrical fixing member 21 that is substantially parallel to the camshaft l. The fixing member 21 is fixed to the cam cases 24 and 25 via holding members 22 and 23 in a substantially airtight manner, and a drive member for displacing the cam piece 3 along the axial direction of the camshaft 1 is provided on the outer periphery. 26 is slidably fitted. Holding member 22.2
Buffer members 28 and 29 are attached to the portions facing into the fixed member 21 of No. 3, respectively, for mitigating the shock when a plunger 27, which will be described later, collides with it.

The plunger 27 is slidably fitted inside the fixing member 21 in a substantially airtight manner, and the plunger 27 is slidably fitted inside the fixing member 21 to allow the left ventricle 30 to pass through the fixing member 21.
and the right ventricle 31. Both ends of the plunger 27 are
It is molded to a slightly smaller diameter than other parts. First and second escape holes 32 and 33 are formed below the side of the fixing member 21, allowing the left chamber 30 and the right chamber 31 to communicate with the atmosphere, respectively, and which are closed by the plunger 27. 1st
In the position shown in FIG. 2 where the cam 5 engages with the rocker arm 9, the left chamber 30 communicates with the atmosphere through the first relief hole 32, and in the position where the second cam 6 engages with the rocker arm 9, the left chamber 30 communicates with the atmosphere through the first relief hole 32. , the right ventricle 31 communicates with the atmosphere via the second escape hole 33.

A pin 35 screwed onto the drive member 26 is inserted into a radial hole 34 formed in the center of the plunger 27, thereby integrally coupling the plunger 27 and the drive member 26. The bottle 35 is inserted through an elongated hole 36 formed parallel to the axial direction of the fixing member 21, and is movable while being regulated by the elongated hole 36. That is, plunger 27 and drive member 26 are prevented from rotating relative to fixed member 21 and are movable along this fixed member 21 .

A cylindrical portion 37 is formed on the opposite side of the drive member 26 from the pin 35, and a timing plunger 3 is disposed within this cylindrical portion 37.
8 is slidably accommodated. Pin 3 of the radial hole 34
A spring 39 and a spherical locking member 4 are provided on the end surface side portion of 5.
0 is accommodated. The locking member 40 is slidably supported within the radial hole 34 and is urged by a spring 39 to constantly abut the timing plunger 38 while the timing plunger 3
8 is constantly engaged with the flanged member 8 that fits into the slit 41 formed in the cylindrical portion 37.

A pair of guide members 45, 45 are provided adjacent to the cylindrical portion 37 (see FIG. 1). These guide members 45.45
extend in the direction of the moving force of the driving member 26, that is, along the longitudinal direction of the fixed member 21, and engage with both sides of the cylindrical portion 37 to guide it. Therefore, the cylindrical portion 37
Even if it is biased in the rotational direction by the rotation of the flange-like member 8
There is no risk of it coming off. As a result, the cylindrical portion 37 is always connected to the cam piece 3, ensuring normal operation of the device of this embodiment.

First and second locking holes 42 , 43 are bored in a portion of the fixing member 21 opposite to the elongated portion 36 , and these locking holes 42 , 43 are connected by a thin hole 44 . Locking hole 4
2.43 are located at positions corresponding to both ends of the elongated hole 36, into which the locking members 40 can be deeply inserted. −
The width of the wide thin hole 44 is smaller than the diameter of the locking member 40, and only the timing plunger 38 can be inserted into this thin hole 44.

The brim member 8 of the cam piece 3 has a large diameter portion 8a and a small diameter portion 8b, as shown in FIG.

When the small diameter portion 8b engages with the timing plunger 38, the locking member 40 pushes up the timing plunger 38 and deeply fits into the locking hole 42 or 43, thereby firmly fixing the driving member 26 and the plunger 27 to the fixed member 21. Fixed to. On the other hand, when the large diameter portion 8a engages with the timing plunger 38, the locking member 40 is pushed down by the timing plunger 38 and shallowly fits into the locking hole 42 or 43, so that the driving member 26 And the locking force of the plunger +27 to the fixing member 21 is weakened. The large diameter portion 8a is configured to push down the timing plunger 38 at the same time that the cam 5.6 finishes driving the rocker arm 9.

When the locking force of the locking member 40 to the fixing member 21 is weak, the plunger 27 is moved in the left-right direction in the figure by the air pressure acting on the left chamber 30 or the right chamber 31. The first and first electromagnetic control wells 50 and 51 supply compressed air to the left ventricle 30 and right ventricle 31, respectively. The first electromagnetic control well 50 communicates with the left ventricle 30 via a passage 52 and with the pressure accumulator 70 via a passage 53. The second electromagnetic control valve 51 communicates with the right ventricle 31 via a passage 54 and with the pressure accumulator 70 via a passage 55. The second electromagnetic control valve 51 has a passage 54
．． 55 is connected to a housing 56, which is biased by a solenoid 58 and a spring 59 to open and close passages 54 and 55, and is a conventionally known two-boat solenoid valve. That is, when the solenoid 58 is not energized, the valve body 57 is biased by the spring 59 to close the passage 54.
, 55 are shut off, and when the solenoid 58 is energized, the valve body 57 compresses the spring 59 and is attracted by the solenoid 58 to communicate the passages 54 and 55, allowing the compressed air in the pressure accumulator 70 to flow into the right chamber 31. Introduce. Note that the first electromagnetic control valve 50 also
Since it has the same configuration as the electromagnetic control valve 51, the explanation thereof will be omitted.

The pressure accumulator 70 is a conventionally known vane type F pump 7.
It is supplied with compressed air from 1 and stores this air. The suction lower 2 of the air pump 71 is connected to the atmosphere via a conduit and an air filter (not shown), and the air pump 71 pressurizes the air sucked in from the suction lower 2 and discharges it from the discharge lower 3, and then connects the check valve 74 and the conduit. 75 to the pressure accumulator 70. The check valve 74 consists of a ball valve 76 and a spring 77. The ball valve 76 is biased by the spring 77 to close 1t75, and the air pump 71
It is opened only when air with a certain pressure or higher is discharged, and high pressure air is guided to the pressure accumulator 70.

The first and second electromagnetic control valves 50.5+ and the air pump 71 are driven by a computer 80.

The computer 80 is connected to a pressure detector 81 provided in the pressure accumulator 70 via a conductor 82, and also receives an engine speed signal SI and a water temperature or oil temperature signal 32.
, and engine load signal S3 are input. However, 1. The computer 80 drives the air pump 71 based on the signal from the pressure detector 81, and controls the pressure in the pressure accumulator 70 to a substantially constant value. Further, the computer 80 receives the signal S+
, Sz.

The following processing is performed based on S, and if it is necessary to switch the cam, the electromagnetic control valve 5 is
0.51. That is, when the oil temperature is below a predetermined value, the first cam 5 for low speed is used, and when the oil temperature is above a predetermined value, the second cam 5 for high speed is used when at least one of engine speed and engine load exceeds a predetermined value. Cam 6 will be used. At this time, for example, regarding the engine rotation speed, the rotation speed N1 when switching from the first cam 5 to the second cam 6 is higher than the rotation speed N2 when switching from the first cam 5 to the second cam 6, and hysteresis is provided, and the same applies to the engine load. A hysteresis is provided.

Since the device of this embodiment has the above-mentioned configuration, it operates as follows to switch the cams 5 and 6.

In the state shown in FIGS. 1 and 2, the rocker arm 9
is engaged with the first cam 5 for low speed, and the electromagnetic control valve 5 is engaged with the first cam 5 for low speed.
0.51 are both blocking passages 52, 53 and 54° 55, respectively. On the other hand, the locking member 40 of the timing mechanism 20 is deeply fitted into the locking hole 43, that is, by approximately 1/2 of the spherical diameter of the locking member 40. Therefore, the drive member 26 is fixed to the fixed member 21 and the fixed member 21
There is no displacement in the axial direction. Thus, the cam piece 3 does not move along the camshaft 1, and the first cam 5 rotates together with the camshaft 1 to drive the rocker arm 9 and open and close the valve 11.

During this rotation of the camshaft 1, the large diameter portion 8a and the small diameter portion 8b of the brim member 8 of the cam piece 3 alternately engage with the timing plunger 38 to push it down. When the small diameter portion 8b engages with the timing plunger 38, the locking member 40 is deeply inserted into the locking hole 43 as described above, but when the large diameter portion 8a engages with the timing plunger 38, the locking member 40 is pushed down by the timing plunger 38 into the locking hole 43 as shown in FIGS. 3 and 4. The penetration depth becomes shallow. However, as described above, the electromagnetic control valves 50 and 51 are closed, compressed air is not supplied to the left ventricle 30 and right ventricle 31, and the plunger 27 is not energized, so the drive member 26 is not displaced. . Further, at this time, the drive member 26 does not move due to engine vibration or the like. On the other hand, due to the rotation of the camshaft 1, that is, the rotation of the cam piece 3, the drive member 26 is constantly biased in the rotational direction via the cam surface of the brim member 8 and tries to rotate. Since the rotational movement of the portion 37 is always restricted by the guide member 45,
It never rotates. Therefore, the drive member 26 is always connected to the cam piece 3, ensuring reliable operation of the variable valve device.

Now, for example, if the engine speed increases and it becomes necessary to switch to the second cam 6 for high speed, the computer 80
energizes the solenoid 58 to drive the electromagnetic control valve 51, displacing the valve body 57 and communicating the passages 54 and 55. Air at a constant pressure is always stored in the pressure accumulator 70 via an air pump 71, and this air is supplied to the right ventricle 31 by communicating with the passages 54 and 55. As a result,
Plunger 29 is biased toward the left in FIG. Here, if the locking member 40 of the timing mechanism 20 is deeply fitted into the locking hole 4'i as shown in FIG. 1 or FIG. 2, the plunger 29 cannot move. , the cam piece 3 is also fixed. In this case, it is a fixed period including the time when the cam 5 opens the intake and exhaust valves, and the cam piece 3 is not moved at this time.

However, when the camshaft 1 rotates further and the cam 5 closes the intake and exhaust valves, and the cam is ready to be switched,
The large diameter portion 8a of the collar member 8 comes to engage with the timing plunger 38. Then, the locking member 40 is pushed down by the timing plunger 38, and as shown in FIGS. 3 and 4, the locking member 40 is inserted into the locking hole 43 shallowly, and
The plunger 27 moves to the left due to the air pressure acting on the right chamber 31 and stops at a position where the locking member 40 fits into the locking hole 42 . As a result, the second cam 6 comes to engage with the opening and the car arm 9, and the switching of the cams is completed.

During this movement of the plunger 27, the locking member 40 enters the radial hole 34, and the timing plunger 38 moves into the fifth
It engages slotted hole 44 as shown in the Figures and FIG. 6, and pin 35 is guided in elongated hole 36 as shown in FIG. Therefore, the drive member 26 and the plunger 27 are smoothly displaced along the fixed member 21. Further, since the cylindrical portion 37 of the driving member 26 moves while being guided by the guide member 45, there is no risk of it coming off the flange member 8 of the cam piece 3. Furthermore, since the end of the plunger 27 comes into contact with the buffer material 28 when the bottle 35 reaches the end of the elongated hole 36, it is possible to prevent collision noise from occurring when switching the cam, and to avoid impact on the bottle 35, etc. It is possible to improve their durability by preventing them from acting. Furthermore, at the end of this switching operation, the inside of the right ventricle 31 is communicated with the atmosphere through the relief hole 33, so the inside of the right ventricle 31 quickly returns to atmospheric pressure, and the switching from the second cam 6 to the first cam 5 is also performed. It's done smoothly.

Further, according to this embodiment, the locked state of the timing mechanism 20 does not depend only on the elastic force of the spring 39, but is related to the fitted state of the locking member 40 and the locking holes 42, 43. Therefore, the spring 39 must be designed so that the timing plunger 38, the locking member 40, and the collar member 8 are always in contact with each other at a fixed position where either of the cams 5 and 6 engages the rocker arm 9. (1) There is no need to determine the spring constant with high precision.On the other hand, since the locking member 40 has a spherical shape, the contact area with the locking holes 42 and 43 is small, and therefore the large diameter part of the collar member 8 When pressed by 8a, it retreats smoothly, increasing the responsiveness of the timing mechanism 20.

Note that switching from the second cam 6 to the first cam 5 is performed in exactly the same manner as described above, and in this case, the first electromagnetic control valve 5
It is sufficient to drive 0.

Effects of the Invention As described above, according to the present invention, there is no possibility that the timing mechanism will come off the cam piece, and the variable valve device can always operate reliably, which is a disadvantage.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing one embodiment of the present invention, FIG. 2 is a system diagram including a longitudinal section of the embodiment device of FIG. 1, and FIG.
4 is a sectional view similar to that shown in the figure, showing a state in which the locking member is shallowly fitted into the locking hole; FIG. 4 shows the same state as shown in FIG. 3; The cutaway cross-sectional view, FIG. 5, shows that the locking member is completely inserted into the radial hole,
FIG. 6 is a plan view showing the locking hole and the narrow portion, and FIG. 7 is a plan view showing the long portion. 3--Cam piece, 5.6--Cam, 11--Valve (intake/exhaust valve), 20- Timing mechanism, 21-- Fixed member, 37-- Cylindrical part (connecting part), 45- Guide Element. Figure 1, Figure 3, Figure 4, Figure 6, Figure 5, and 7.

Claims (1)

[Claims] 1. A timing mechanism supported reciprocally along a fixed member is connected to a cam piece having a plurality of cams that open and close the intake and exhaust valves of the internal combustion engine, and the movement of the timing mechanism opens and closes the intake and exhaust valves. A variable valve device that selectively switches a driven cam, characterized in that a guide member that can engage with the connecting portion of the timing mechanism is disposed along the moving direction of the connecting portion with the cam piece. Valve device.