JPH05332109A - Valve system of internal combustion engine - Google Patents

Abstract

PURPOSE:To more precisely carry out valve control by assembling a connection change-over mechanism to control an opening valve lift amount and an opening angle of a valve by way of changing over connection and disconnection of a plural number of cam followers and a phase adjustment mechanism to control opening and closing time of the valve by way of relatively revolving a crankshaft and a cam. CONSTITUTION:Between each of a plural number of cam followers 7-9 to move in accordance with rotation of a camshaft 2 furnished with a plural number of cams 4, 5 of different shapes against an air intake valve 1 or an exhaust valve for one cylinder, connection change-over mechanisms 10a, 10b capable of changing over connection and disconnection of the cam followers 7-9 are provided so as to control the working state of the air intake valve 1 or the exhaust valve in accordance with the driving state of an engine. Additionally, between a crankshaft and the cams 4, 5, a phase adjustment mechanism 12 capable of relatively revolving the crankshaft and the cams is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a crankshaft of an engine in which a camshaft having a plurality of cams having different shapes for one cylinder for an intake valve or an exhaust valve is interlocked and connected, and responds to the rotation of the camshaft. A valve operating device for an internal combustion engine is provided between a plurality of cam followers, which is provided with a connection switching mechanism capable of switching connection and disconnection of the cam followers in order to control the operation mode of the intake valve or the exhaust valve according to the operating state of the engine. Regarding

[0002]

2. Description of the Related Art Conventionally, such a valve operating device is known, for example, from Japanese Patent Laid-Open No. 61-199911.

[0003]

By the way, in the above-mentioned prior art, it is possible to switch connection and disconnection of a plurality of cam followers individually driven by a plurality of cams provided on the cam shaft, and to connect the cam followers to each other. By selecting the cam for opening and closing the intake valve or exhaust valve by switching the connection and disconnection, the lift amount of the intake valve or exhaust valve corresponding to the protrusion amount of the high position of each cam and the lift amount of each cam are selected. The opening angle of the intake valve or the exhaust valve is controlled according to the central angle range of the high position. However, in order to perform the valve operating control of the internal combustion engine more precisely, the above-mentioned conventional ones have a large limitation in response to the demand for making the cam shapes largely different, and the number of cams and the storage space are difficult.

The present invention has been made in view of such circumstances, and not only the lift amount and the opening angle of the intake valve or the exhaust valve, but also the phase for advancing or delaying the valve opening timing or the valve closing timing. An object of the present invention is to provide a valve operating system for an internal combustion engine, which can be controlled.

[0005]

In order to achieve the above object, according to the present invention, a camshaft having a plurality of cams of different shapes for one cylinder for an intake valve or an exhaust valve is interlocked with a crankshaft of an engine. Between the cam followers that are connected and respond to the rotation of the camshaft, the connection and disconnection of the cam followers can be switched so as to control the operation mode of the intake valve or the exhaust valve according to the operating state of the engine. In a valve train of an internal combustion engine provided with a switching mechanism, a phase adjusting mechanism that allows relative rotation of the crankshaft and the cam is provided between the crankshaft and the cam.

[0006]

According to the above construction, the valve opening lift amount and opening angle of the intake valve or the exhaust valve can be controlled by switching the connection and disconnection of the plurality of cam followers by the connection switching mechanism, and the phase adjusting mechanism can be used. The opening / closing timing of the intake valve or the exhaust valve can be controlled by relatively rotating the crankshaft and the cam.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention applied to a multi-cylinder internal combustion engine will be described below with reference to the drawings. First, in FIGS. 1 and 2, an intake valve provided corresponding to a cylinder of an engine main body E will be described. Reference numeral 1 denotes a raised portion 3, a low speed cam 4 and a high speed cam 5 which are integrally provided on a cam shaft 2 which is rotationally driven from a crank shaft of an engine at a speed reduction ratio of 1/2, and a rocker which is parallel to the cam shaft 2. First, second and third rocker arms 7 as cam followers pivotally supported on the shaft 6,
8, 9 and first and second rocker arms 7, 8 and connection switching mechanisms 10a, 10b provided between the second and second rocker arms 8, 9 and a pulley 11 and a camshaft 2 which are linked and linked to the crankshaft. It is opened and closed by cooperation with the phase adjusting mechanism 12 provided therebetween.

The camshaft 2 is rotatably arranged above the engine body E, and the low speed cam 4, the ridge 3 and the high speed cam 5 are adjacent to each other in the axial direction and integrated with the camshaft 2. To be done. The raised portion 3 is formed in a circular shape concentric with the cam shaft 2, and the low speed cam 4 has a base circular portion 4a concentric with the cam shaft 2 and a high portion 4b projecting radially outward from the base circular portion 4a. .. Also high speed cam 5
Has a base circular portion 5a that is concentric with the camshaft 2 and a high portion 5b that projects radially outward from the base circular portion 5a. The high portion 5b has a larger protrusion amount than the high portion 4b and has a center. It is formed with a large angular range.

The rocker shaft 6 is fixedly arranged below the cam shaft 2. This rocker shaft 6 has
A first rocker arm 7 having a cam slipper 13 slidingly contacting the low speed cam 4 at the upper portion, a second rocker arm 8 having a slipper 14 slidingly contacting the raised portion 3 at the upper portion, and a cam slipper 15 slidingly contacting the high speed cam 5 at the upper portion. And a third rocker arm 9 of the rocker shaft 6 are pivotally supported adjacent to each other in the axial direction of the rocker shaft 6.

The intake valve 1 is interlocked and connected to the second rocker arm 8. That is, the intake valve 1 is urged in the valve closing direction, that is, upward by the valve spring 17 interposed between the flange portion 16 provided at the upper end of the intake valve 1 and the engine body E, and the intake valve 1 is attached to the tip of the second rocker arm 8. A tappet screw 18 abutting on the upper end of the intake valve 1 is screwed so as to be able to move forward and backward.

Referring also to FIG. 3, the first and third rocker arms 7 and 9 are slid on the low speed cam 4 and the high speed cam 5 by the elastic biasing means 19 provided between the first and third rocker arms 7 and 9. Ejection is urged in the contact direction. This bullet urging means 19
Comprises a bottomed cylindrical lifter 20 whose closed ends are in contact with the first and third rocker arms 7 and 9, and a spring 21 interposed between the lifter 20 and the engine body E.
0 is slid into a bottomed hole 22 formed in the engine body E.

In FIG. 4, the connection switching mechanism 10a includes a connection pin 23a which is movable between a position for connecting the first and second rocker arms 7 and 8 and a position for releasing the connection state, and the connection pin 23a. It has a stopper 24a for restricting movement and a return spring 25a for urging the stopper 24a to move the connecting pin 23a to the connection releasing side.

The second rocker arm 8 is provided with a first bottomed guide hole 26a which opens toward the first rocker arm 7 side and is parallel to the rocker shaft 6 and closes the first guide hole 26a. A step portion 27a facing the open end side is provided on the end side. A connecting pin 23a is slidably fitted in the first guide hole 26a, and a hydraulic chamber 28a is defined between the connecting pin 23a and the closed end of the first guide hole 26a.

The first rocker arm 7 has a first guide hole 2
Corresponding to 6a, a bottomed second guide hole 29a opened to the second rocker arm 8 side is bored in parallel with the rocker shaft 6, and a disk-shaped stopper 24a is slid into the second guide hole 29a. To be done. A regulation step 30a facing the open end is provided on the closed end side of the second guide hole 29a, and an insertion hole 32a is coaxially bored on the closed end. Moreover, the guide rod 3 is provided coaxially and integrally with the stopper 24a.
3a is inserted into the insertion hole 32a. Further stopper 24
a and a guide rod 33 between the closed end of the second guide hole 29a.
A coil-shaped return spring 25a that surrounds a is interposed.

The axial length of the connecting pin 23a is such that the other end is located between the first and second rocker arms 7 and 8 when one end of the connecting pin 23a abuts on the step portion 27a, and the stopper 2 is provided.
4a comes into contact with the regulation step portion 30a until the second guide hole 29
It is set so that one end remains in the first guide hole 26a when it enters a.

On the other hand, in the rocker shaft 6, two oil passages 34a, 34b are formed by a partition wall 35 extending in the axial direction.
The oil pressure is supplied to the oil passages 34a, 34b from a hydraulic pressure supply source (not shown). Moreover, one oil passage 34a is always in communication with the hydraulic chamber 28a regardless of the swinging state of the second rocker arm 8.

The connection switching mechanism 10b provided between the second and third rocker arms 8 and 9 has a connection pin 23b, a stopper 24b and a return spring 25b, and is basically constructed in the same manner as the connection switching mechanism 10a. Although detailed description is omitted, the hydraulic chamber 28b of the connection switching mechanism 10b is not affected by the swinging state of the second rocker arm 8.
Always communicates with the oil passage 34b in the rocker shaft 6.

In FIG. 5, the phase adjusting mechanism 12 is integrally provided on a rotary shaft 46 coaxially connected to the camshaft 2 and a pulley 11 around which a timing belt 45 for transmitting power from the crankshaft is wound. A housing 47 that coaxially surrounds the rotating shaft 46, a piston 48 that slides between the rotating shaft 46 and the housing 47, and a servo valve 49 that regulates the movement amount of the piston 48 are provided.

The rotary shaft 46 is formed into a bottomed cylindrical shape having a shaft portion 50 integrally at its closed end, and a screw member 51 penetrating the closed end is screwed into the camshaft 2. The shaft 50 is coaxially connected to the end of the camshaft 2. Further, the housing 47 is formed in a bottomed cylindrical shape that is open to the camshaft 2 side, and the pulleys 11 are integrally provided at the tips of a plurality of arm portions 52 that project from the outer peripheral surface of the housing 47. At the open end of this housing 47,
An outer peripheral edge of a cap 55 including an end plate portion 53 slidably contacting the outer surface of the rotary shaft 46 on the closed end side and a cylindrical portion 54 slidably contacting the outer surface of the shaft portion 50 is fitted to the inner surface of the housing 47 on the closed end side. Is in sliding contact with the tip of the rotary shaft 46. Therefore, the housing 47 and the pulley 11 are prevented from moving relative to the rotating shaft 46, that is, the cam shaft 2 in the axial direction, but are allowed to rotate relative to each other about the axis.

The outer surface of the piston 48 is the housing 4
It is formed in a ring shape so as to be in sliding contact with the inner surface of 7 and the inner surface in sliding contact with the outer surface of the rotating shaft 46. A ring-shaped meshing portion 56 is arranged at a position spaced apart from the piston 48 in the axial direction.
The inner edges of are connected by a connecting cylinder portion 57 that coaxially surrounds the rotation axis. As a result, a hydraulic chamber 58 is defined between the piston 48, the meshing portion 56, the connecting tubular portion 57, and the housing 47 for exerting an oil pressure that pushes the piston 48 in one axial direction thereof, that is, in the right side of the drawing. ..

Helical outer teeth 59 are formed on the outer surface of the meshing portion 56, and the helical outer teeth 59 are meshed with the helical inner teeth 60 formed on the inner surface of the housing 47. Further, helical inner teeth 61 are engraved on the inner surface of the meshing portion 56, and the helical inner teeth 61 mesh with the helical outer teeth 62 engraved on the outer surface of the rotary shaft 46. Therefore the piston 48
By the axial movement of the housing 47, that is, the pulley 1.
1 and the rotary shaft 46, that is, the camshaft 2 relatively rotate about the axis.

A first cylindrical portion 63 extending opposite to the connecting cylindrical portion 57 is integrally connected to the inner edge of the meshing portion 56, and a tip end of the first cylindrical portion 63 contacts the closed end of the housing 47. A flange portion 64 that is in contact with and extends radially inward is continuously provided, and a second cylindrical portion 65 that is slidably fitted in a through hole 66 formed at the center of the closed end of the housing 47 is provided on the inner edge of the flange portion 64.
Are continuously connected.

Therefore, the movement of the piston 48 on the other side in the axial direction (the left side in FIG. 5) is restricted by the flange portion 64 contacting the housing 47. Further, a plurality of elongated holes 67 curved in the circumferential direction are formed in the flange portion 64, and the elongated holes 67 of the rotary shaft 46 are brought into contact with the closed end of the housing 47. A plurality of abutting protrusions 46a integrally formed at the tip are inserted, and the piston 48 is rotatable relative to the rotary shaft 46 within a range in which the abutting protrusions 46a abut both ends of the elongated hole 67. is there. Further housing 4
A cap-shaped cap 68 that is inserted into the housing 47 to close the through hole 66 is fixed to the device 7.

The servo valve 49 is provided with a cylindrical sleeve 69 that slides on the rotary shaft 46, and a cylindrical spool 70 that slides inside the sleeve 69.
An operation shaft 71 that is coaxially inserted into the cam shaft 2 and the rotation shaft 46 is connected. A return spring 72 is interposed between one end of the sleeve 69 and the closed end of the rotary shaft 46. The spring force of the return spring 72 causes the sleeve 69 to move in a direction in which the other end abuts on the flange 64. Therefore, the piston 48 is spring-biased to the other side in the axial direction against the hydraulic pressure in the hydraulic chamber 58.

The engine main body E is provided with a first hydraulic pressure supply passage 74 connected to the hydraulic pump 73, and the camshaft 5 is provided with an annular groove 75 communicated with the first hydraulic pressure supply passage 74 on the outer surface thereof. A second hydraulic pressure supply passage 76 communicating with the annular groove 75 is provided. Further, a third hydraulic pressure supply passage 78, which is in constant communication with the second hydraulic pressure supply passage 76, is bored in the rotary shaft 46, and
An annular groove 79 communicating with the third supply passage 78 is provided on the inner surface of 6. A pair of annular seal members 80 and 81 are interposed between the cam shaft 2 and the engine body E so as to sandwich the annular groove 75 of the cam shaft 2 therebetween, and the second and third annular seal members 80 and 81 are provided between the cam shaft 2 and the rotary shaft 46. Hydraulic supply path 76,
Annular seal member 82 for maintaining communication between 78
Is installed.

An oil hole 84, which always communicates with the annular groove 79 regardless of the axial position with respect to the rotating shaft 46, is bored along the one diameter line in the sleeve 69, and the opening end of the oil hole 84 on the inner surface side is formed. An annular groove 85 is bored on the inner surface of a position adjacent to the one side in the axial direction (on the right side in FIG. 5). Moreover, the sleeve 69 and the collar portion 64 that abuts the sleeve 69 are provided with a passage 86 that allows the annular groove 85 to communicate with the hydraulic chamber 58. Further, an oil pressure release passage 87 is formed in the closed end of the rotary shaft 46 and the end plate portion 53 of the cap 55.

An annular groove 88 is formed on the outer surface of the spool 70, and the annular groove 88 extends along the axial direction of the spool 70.
Is set to such an extent that the oil hole 84 and the annular groove 85 can communicate with each other. The spool 70 relatively moves in the axial direction from the blocking position with respect to the sleeve 69 so that only the oil hole 84 communicates with the annular groove 88, and moves between the oil hole 84 and the annular groove 85 via the annular groove 88. Can be moved between three relative positions in the axial direction: a supply position in which the annular groove 85 communicates with the sleeve 69 and a release position in which the annular groove 85 communicates with the hydraulic pressure release passage 87 relative to the other side in the axial direction from the blocking position. A spring 89 that urges the spool 70 to the other side in the axial direction is interposed between the cap 68 and the spool 70.
Further, a stopper 90 which projects inward in the radial direction is integrally provided at an end portion on one axial side of the sleeve 69, and the stopper 90 abuts on the spool 70 to regulate mutual relative movement in the axial direction.

Next, the operation of this embodiment will be described.
First, when the operation shaft 71 is moved in the axial direction by the phase adjusting mechanism 12 to move the spool 70 from the cut-off position shown in the figure to the axial direction one side, that is, the spool 70 is moved from the shown position to the axial direction shown in FIG. When it is relatively moved in one axial direction with respect to 69, the oil hole 84 and the annular groove 85 reach the supply position where they are communicated with each other through the annular groove 88, and the hydraulic pressure from the hydraulic pump 73 is supplied to the hydraulic chamber 58. The piston 48 is pressed and driven in one axial direction against the spring force of the return spring 72. However, in response to the movement of the piston 48 in one axial direction, the housing 47 and the pulley 11 are
And the rotary shaft 46 and the cam shaft 2 relatively rotate,
The opening / closing timing of the intake valve 1 becomes early, for example. Moreover, since the sleeve 69 also moves in one axial direction in accordance with the axial movement of the piston 48, the spool 70 relatively moves in the other axial direction with respect to the sleeve 69, and the spool 70 and the sleeve 69 move in the axial relative direction. The position is a blocking position. Therefore, the amount of movement of the piston 48 is determined according to the amount of axial movement of the spool 70, and the amount of advance of the opening / closing timing is determined accordingly, so that the amount of advance of the opening / closing timing can be controlled steplessly according to the amount of operation of the spool 70. Becomes

When the operating shaft 71 is moved to the other side in the axial direction and the spool 70 is relatively moved from the shut-off position to the other side in the axial direction, the annular groove 85 reaches the release position communicating with the hydraulic release path 87, and the hydraulic chamber is opened. The hydraulic pressure at 58 is released. In response to this, the piston 48 moves to the other side in the axial direction by the spring force of the return spring 72, and relative rotation in the opposite direction to the above occurs between the pulley 11 and the cam shaft 5, and the opening / closing timing of the intake valve 1 is delayed. Moreover, since the sleeve 69 moves to the other side in the axial direction together with the piston 48, and the spool 70 moves to the one side in the axial direction relative to the sleeve 69, the relative position in the axial direction of the spool 70 and the sleep 69 becomes the cutoff position. Become. Therefore, the opening / closing timing delay amount is determined according to the axial movement amount of the spool 70, and the opening / closing timing delay amount can be continuously controlled according to the operation amount of the spool 70.

By thus driving the spool 70 in the axial direction by the operation shaft 71, the piston 48 is driven following the movement of the spool 70, and the opening / closing timing of the intake valve 1 is advanced steplessly. It becomes possible to control the speed indefinitely.

Further, the oil passages 34a, 3 in the rocker shaft 6
By supplying or releasing the hydraulic pressure to 4b, the connection switching mechanisms 10a and 10b are brought into the connected state or the released state, whereby the intake valve 1
It is possible to control the valve opening lift amount and the opening angle. That is, when the connection switching mechanisms 10a and 10b are both in the connection release state, the rocker arms 7 to 9 swing independently of each other, so that the intake valve 1 has the second rocker arm 8 in sliding contact with the raised portion 3. It does not open and close even though it is stationary. When the connection switching mechanism 10a is in the connected state and the connection switching mechanism 10b is in the connection released state, the first
As the second rocker arms 7 and 8 are connected, the intake valve 1 opens and closes with a lift amount and an opening angle according to the shape of the low speed cam 4. Further, when the connection switching mechanism 10a is released and the connection switching mechanism 10b is connected, the intake valve 1 conforms to the shape of the high-speed cam 5 as the second and third rocker arms 8 and 9 are connected. It opens and closes depending on the lift amount and opening angle.

In this way, the opening / closing timing of the intake valve 1 is
The lift amount and the opening angle are controlled by the phase adjusting mechanism 12, and the connection switching mechanisms 10a and 10b are controlled. By combining these controls, the valve operating control of the engine can be made more precise.

Although the valve operating device for the intake valve 1 has been described in the above embodiments, the present invention can be applied to the valve operating device for the exhaust valve.

[0034]

As described above, according to the present invention, the valve opening lift amount and the opening angle of the intake valve or the exhaust valve can be controlled by switching the connection and disconnection of a plurality of cam followers by the connection switching mechanism. Moreover, since the opening / closing timing of the intake valve or the exhaust valve can be controlled by relatively rotating the crankshaft and the cam by the phase adjusting mechanism, more precise valve control can be performed by combining those controls. ..

[Brief description of drawings]

FIG. 1 is a cross-sectional plan view of essential parts showing an embodiment of the present invention.

FIG. 2 is a sectional view taken along line 2-2 of FIG.

3 is a sectional view taken along line 3-3 of FIG.

4 is a sectional view taken along line 4-4 of FIG.

FIG. 5 is an enlarged vertical sectional view of the phase adjusting mechanism.

[Explanation of symbols]

 1 intake valve 2 cam shaft 4 low speed cam 5 high speed cam 7, 8, 9 rocker arm as a cam follower 10a, 10b connection switching mechanism 12 phase adjusting mechanism

Claims (1)

[Claims] 1. A camshaft (2) having a plurality of cams (4, 5) of different shapes for one cylinder for an intake valve (1) or an exhaust valve is linked and linked to a crankshaft of an engine, Between the plurality of cam followers (7, 8, 9) that respond to the rotation of the shaft (2), the cam followers (7, 8, 9) are arranged to control the operating mode of the intake valve (1) or the exhaust valve according to the operating state of the engine. In a valve train of an internal combustion engine, which is provided with a connection switching mechanism (10a, 10b) capable of switching connection and disconnection of the crankshaft and the cam (4, 5), the crankshaft and the cam ( 4,5)
1. A valve operating system for an internal combustion engine, comprising a phase adjusting mechanism (12) capable of relatively rotating.