JP5188155B2 - Variable valve operating device for internal combustion engine - Google Patents

Description

  The present invention relates to a variable valve operating apparatus for an internal combustion engine that can change a drive phase of an intake valve, an exhaust valve, and the like and a valve lift amount.

  In an internal combustion engine such as an automobile engine, the drive phase and lift amount of the intake and exhaust valves are changed according to the operating state of the internal combustion engine to purify the exhaust gas exhausted from the engine or reduce the fuel consumption of the automobile. Such variable valve gears are known.

As such a variable valve operating apparatus, for example, a third arm is provided between a first arm that drives a valve and a second arm that is swung by a cam, and the valve is driven through the third arm. An invention of a variable valve operating apparatus for an internal combustion engine is known in which the phase and lift amount of the valve are continuously changed by displacing the swing support point of the two arms. (For example, see Patent Document 1.)
JP 2004-150301 A

  However, since the variable valve operating apparatus described in the above Japanese Patent Application Laid-Open No. 2004-150301 has a configuration in which the third arm is provided above the rocker shaft, when such a variable valve operating apparatus is used for an engine, the engine There was a risk of increasing the height dimension of. In particular, the cab-over type truck has an engine arranged at the lower part of the driver's seat, originally has little space between the engine and the driver's seat floor, and the variable valve system increases the engine height. It was not preferable in design.

  Further, in the case of a conventional general continuous phase variable valve operating apparatus, if the closing timing of the intake valve is delayed, the opening timing is also delayed. For this reason, if the closing timing of the intake valve is delayed, intake and exhaust valve overlaps are reduced or eliminated, and there is a problem that fuel consumption deteriorates due to pumping loss.

  An object of the present invention is to provide a variable valve operating apparatus that can continuously change a valve drive phase and a valve lift amount with a simple configuration and that can keep the height dimension of an engine small. To do.

  In the present invention, in order to achieve the above object, the variable valve operating apparatus is configured as follows.

1. An intake valve and an exhaust valve driven by a camshaft rotatably provided on a cylinder head of an internal combustion engine, a rocker shaft rotatably provided on the internal combustion engine, and a cam formed on the camshaft. A rocker arm mechanism for opening and closing at least one of the valves,
The rocker arm mechanism is swingably supported by the rocker shaft and swings about a fulcrum provided on the rocker shaft side, driven by the cam and a first arm formed to be able to drive the valve. A second arm that is provided, and a conversion that is provided between the first arm and the second arm, and transmits the swing displacement of the second arm to the first arm to drive the first arm. A member and a drive mechanism for rotating the rocker shaft to displace the fulcrum,
Further, the displacement of the fulcrum by the drive mechanism moves the contact portion of the second arm with the cam along the circumferential direction of the base circle of the cam, and changes the drive phase of the second arm relative to the cam. The variable valve operating apparatus for the internal combustion engine is configured.

  The position of the fulcrum is changed by the drive mechanism, and the drive phase of the second arm relative to the cam is advanced or retarded accordingly, so that the drive of the first arm driven through the second arm and the conversion member is performed. The phase is advanced or retarded.

2. The variable valve operating apparatus for an internal combustion engine according to any one of claims 1 and 2, wherein the drive phase is an angle formed by a position where a peak of the cam starts from a base circle of the cam and a contact position between the second arm and the cam. It was decided to change continuously accordingly .
3. The variable valve operating apparatus for an internal combustion engine according to 3, 1, wherein the conversion member includes a sliding surface portion that slides along a guide surface portion of a cylinder head side member provided in the cylinder head, and a second arm. A transmission surface portion that contacts the first arm when the conversion member slides along the sliding surface portion by a swinging operation and drives the first arm;
The transmission surface portion rotates the rocker shaft by the drive mechanism to displace the fulcrum, thereby continuously changing the drive phase of the intake valve or the exhaust valve according to the movement amount of the second arm. It was supposed to be formed to change.

4. The variable valve operating apparatus for an internal combustion engine according to claim 1, wherein the fulcrum is formed by a connecting member provided on the rocker shaft, and the second arm is provided on one end side of the second arm. A base end portion is rotatably supported by the connection member, a contact portion provided on the other end side of the second arm is in contact with the conversion member, and a part of the second arm is in contact with the cam. While abutting, a spring provided on the rocker shaft is engaged with the conversion member, and the second arm is biased to the cam side via the conversion member.

5, in the variable valve system for an internal combustion engine according to 3, a sliding member provided between the guide surface and the sliding surface, said guide surface and said slide surface portion via a sliding member sliding It was decided to touch freely.

6 and 5 , the cylinder head-side member is fixed to a rocker shaft bracket that rotatably holds the rocker shaft.

7, in the variable valve system for an internal combustion engine according to 6, a guide portion for guiding said conversion member to the cylinder head side member provided, said in a direction perpendicular to the sliding direction of said conversion member by said guide portion It was decided to restrict the movement of the conversion member .

According to the variable valve apparatus according to 1, the swing amount of the second arm the first arm is driven by reached isopropylidene by the conversion member.

When the fulcrum is displaced around the axis of the rocker shaft by the drive mechanism, the contact portion of the second arm with the cam is moved along the circumferential direction of the base circle of the cam. Thereby, the drive phase of the 2nd arm with respect to a cam can be changed, and the drive phase of an intake valve or an exhaust valve can be changed continuously.

According to the variable valve operating apparatus described in No. 2, the driving phase of the second arm is changed by changing the angle between the position where the cam crest starts from the base circle of the cam and the contact position between the second arm and the cam. Is changed.

According to the variable valve operating apparatus described in 3, the fulcrum is formed by the connecting member provided on the rocker shaft, and the base end provided on the one end side of the second arm is rotatably supported by the connecting member. Therefore, the second arm can be displaced according to the rotation of the rocker shaft, and the drive phases of the intake valve and the exhaust valve can be continuously changed.
In addition, since the conversion member is not supported by the support shaft as in the prior art, even if the variable valve gear is assembled to the engine, the increase in the height of the engine is suppressed, and the mountability to the vehicle is improved. By reducing the support shaft, the weight can be reduced and the cost can be reduced.

According to the variable valve operating apparatus described in No. 4, by providing the spring for urging the conversion member, the second arm always abuts against the cam and can hold the second arm and the conversion member without rattling. it can.

According to the variable valve operating apparatus described in No. 5 , it is possible to maintain good lubricity and wear resistance by the pad as the sliding member, and to smoothly slide the conversion member along the guide surface portion.

According to the variable valve operating apparatus described in FIG. 6 , since the cylinder head side member is composed of a part of the rocker shaft bracket, the number of parts can be reduced, the assembly process can be facilitated, and the cost can be reduced. it can.

According to the invention described in FIG. 7 , the guide member restricts the movement of the conversion member in the orthogonal direction, can prevent displacement in the axial direction of the rocker shaft, can stabilize the operation, and Dropping and falling can be prevented.

An embodiment of a variable valve operating apparatus according to the present invention will be described with reference to the drawings.
In FIG. 1, the outline of the variable valve apparatus 10 is shown. The variable valve operating apparatus 10 is a valve operating apparatus that opens and closes a valve of an internal combustion engine, and is provided, for example, in a cylinder head (not shown) such as an automobile engine. FIG. 3 shows an example in which the variable valve gear 10 is provided in the intake valve 12. The intake valve 12 is provided in the intake passage 13 of the cylinder head so as to be capable of reciprocating in the axial direction, and is always urged by a valve spring 15 in a direction to close the intake passage 13. The variable valve device 10 may be provided on the exhaust valve side of the engine.

  FIG. 2 shows a specific configuration of the variable valve apparatus 10. As shown in the drawing, the variable valve operating apparatus 10 includes a rocker shaft bracket 20 (cylinder head side member) fixed to the cylinder head, a rocker shaft 22 rotatably supported by the rocker shaft bracket 20, and a rocker shaft. The drive mechanism 24 rotates the shaft 22 around the axis, the rocker arm mechanism 26, the camshaft 28 that drives the rocker arm mechanism 26, and the like.

  The rocker shaft bracket 20 is a member that is screwed to the cylinder head, and holds the rocker shaft 22 rotatably on the cylinder head. The rocker shaft bracket 20 has an arm portion 23 formed in parallel with the mounting direction of the rocker shaft 22, and a pad 25 (sliding member) is attached to the lower surface 23 a (guide surface portion) of the arm portion 23.

  The pad 25 is made of a material having a small frictional resistance and sufficient wear resistance with respect to the conversion member 18 described later, and has an arc shape and a predetermined curvature. The arm 25 may not be provided with the pad 25. Furthermore, you may attach the pad 25 to the conversion member 18 mentioned later.

  The cam shaft 28 includes a cam 30 and is rotatably mounted on the cylinder head. The camshaft 28 is connected to a crankshaft (not shown) of the internal combustion engine via a cam chain or the like, and when the crankshaft rotates, the cam 30 is rotationally driven in the direction indicated by the arrow R1 in FIG. The The cam 30 is formed in a predetermined cam shape suitable for an engine having the variable valve operating apparatus 10.

  The rocker shaft 22 is rotatably supported by the rocker shaft bracket 20 in parallel with the camshaft 28, and a drive mechanism 24 is connected to the end of the rocker shaft 22. The drive mechanism 24 is composed of an electric motor, hydraulic equipment, or the like. When the drive mechanism 24 is driven, the rocker shaft 22 is continuously driven to rotate at an arbitrary angle with the central axis of the rocker shaft 22 as the rotation center. The Further, the rocker shaft 22 is formed with a notch 32 and a stop hole 34. A connection member 36 of a rocker arm mechanism 26, which will be described later, is engaged with the notch 32, and one end of a spring 38 is engaged with the stop hole 34.

  Next, the rocker arm mechanism 26 will be described. The rocker arm mechanism 26 includes a first arm 14 attached to the rocker shaft 22, a second arm 16 in contact with the cam 30, a conversion member 18 disposed between the first arm 14 and the second arm 16, and a connection member 36. And a spring 38 or the like.

  The connection member 36 is a stud bolt, has a spherical universal joint portion 40 on one end side, is screwed into a screw hole 43 formed in the notch portion 32 of the rocker shaft 22, and is fixed by a lock nut 41. When the connecting member 36 is fixed to the rocker shaft 22, the universal joint portion 40 functions as a fulcrum. The connecting member 36 may have a configuration in which the universal joint portion 40 is attached to a normal bolt instead of a stud bolt.

  The spring 38 is a torsion coil spring. A bent portion 39 is formed on one end side, and an operating portion 42 that extends in the axial direction of the rocker shaft 22 and is bent radially outward is formed on the other end side. ing. The bent portion 39 is inserted into the retaining hole 34 formed in the rocker shaft 22 as described above.

  As shown in FIG. 3, the first arm 14 includes annular shaft fitting insertion portions 44 and 45 through which the rocker shaft 22 is inserted, a pressing portion 48 into which the adjustment screw 46 is screwed, and a roller 50. And is rotatably assembled to the outer periphery of the rocker shaft 22.

  The shaft insertion portions 44 and 45 are bifurcated from the pressing portion 48, and a predetermined gap is formed between the shaft insertion portions 44 and 45. The adjusting screw 46 is screwed into the pressing portion 48, and the interval between the first arm 14 and the intake valve 12 can be adjusted by rotating the adjusting screw 46, and is fixed by a lock nut 47 at an appropriate position. Is done. The tip of the adjustment screw 46 is positioned above the intake valve 12, and when the first arm 14 rotates about the rocker shaft 22, the adjustment screw 46 presses the intake valve 12 to open the intake passage 13. The roller 50 is rotatably provided on the upper part of the first arm 14.

  The second arm 16 is formed in a substantially U shape in a side view, and is provided with a base end portion 52 on the lower side and a contact portion 54 on the upper side of the figure formed in the U shape. ing. The base end portion 52 has a recess 55 formed on the upper surface. The concave portion 55 is formed in a substantially hemispherical shape corresponding to the spherical shape of the universal joint portion 40 and is rotatably assembled with the universal joint portion 40 as a fulcrum.

  Further, the second arm 16 is provided with a roller 56 rotatably at an intermediate position between the base end portion 52 and the contact portion 54. The roller 56 contacts the cam 30 when the rocker arm mechanism 26 is assembled to the cylinder head, and when the cam 30 rotates, the second arm 16 is swung around the center of the universal joint 40. Further, the second arm 16 is formed such that at least a portion sandwiched between the shaft insertion portions 44 and 45 has a lateral width substantially equal to the interval between the shaft insertion portions 44 and 45.

  The conversion member 18 is formed in a triangular trapezoidal shape whose one end is elongated, and a sliding surface portion 58 is provided on the upper surface of the drawing, and a transmission surface portion 60 is provided on the lower surface of the drawing. The sliding surface portion 58 is formed to be equal to the curvature of the pad 25 and slides in an arc along the lower surface of the pad 25.

  The transmission surface portion 60 is formed such that the distance from the sliding surface portion 58 has a predetermined value along the sliding surface portion 58. That is, when the conversion member 18 is slid in an arc along the lower surface of the pad 25, the member that contacts the transmission surface portion 60 at a predetermined position moves in a direction perpendicular to the pad 25 as the conversion member 18 moves. It is formed to make a movement.

  Further, a groove portion 62 is formed in the transmission surface portion 60, and the operating portion 42 of the spring 38 is engaged in the groove portion 62 when the rocker arm mechanism 26 is assembled. When the operating portion 42 is engaged in the groove portion 62, the spring 38 biases the conversion member 18 so that the conversion member 18 moves to the second arm 16 side.

  Further, a semi-cylindrical joint 64 is provided between the conversion member 18 and the contact portion 54 of the second arm 16. The joint 64 is attached to the contact portion 54 of the second arm 16 and is slidably fitted to the conversion member 18 to absorb a change in the contact angle between the conversion member 18 and the contact portion 54. In addition, the pressing operation of the second arm 16 is transmitted to the conversion member 18.

  Next, a state in which the variable valve device 10 is assembled to the cylinder head will be described.

  The connecting member 36 is screwed into the screw hole 43 of the notch 32 of the rocker shaft 22 and is fixed by the lock nut 41. The first arm 14 is rotatably attached to the rocker shaft 22 by shaft fitting portions 44 and 45. The spring 38 is assembled between the shaft insertion portions 44 and 45 of the first arm 14, and the bent portion 39 is inserted into the stop hole 34 to prevent rotation.

  The second arm 16 is disposed between the shaft fitting insertion portions 44 and 45 with the concave portion 55 of the base end portion 52 fitted into the universal joint portion 40. The conversion member 18 is disposed at the tip of the contact portion 54 of the second arm 16, and the operating portion 42 of the spring 38 is engaged in the groove 62 of the conversion member 18. As described above, the spring 38 is engaged in advance so that the conversion member 18 is biased toward the second arm 16.

  When the rocker shaft bracket 20 is screwed to the cylinder head, the rocker shaft 22 is rotatably held. As shown in FIGS. 1 and 3, the variable valve apparatus 10 includes the first arm 14 having the rocker shaft. The conversion member 18 is disposed between the first arm 14 and the second arm 16 in contact with the pad 25 while the roller 56 of the second arm 16 is in contact with the cam 30 of the cam shaft 28. The

  A drive mechanism 24 is connected to the end of the rocker shaft 22, and the rocker shaft 22 is positioned in the axial direction by means not shown. The camshaft 28 is provided in advance in the cylinder head.

  Further, since a part of the second arm 16 is sandwiched between the shaft insertion portions 44 and 45, an uneven load is applied to the contact portion between the second arm 16 and the cam 30 or the contact portion between the second arm 16 and the conversion member 18. Even when this occurs, the second arm 16 is prevented from displacing in the axial direction of the rocker shaft 22, and problems such as uneven wear are prevented.

  Next, the operation of the variable valve gear 10 will be described. The rocker shaft 22 is continuously rotated by the drive mechanism 24. For convenience of explanation, the rocker shaft 22 is rotated by three types of angles, neutral, retarded angle, and advanced angle. explain. 3 and 4 show examples of the retarded side, FIGS. 5 and 6 are neutral, and FIGS. 7 and 8 are examples of advanced side.

  In FIG. 3, the rocker shaft 22 is rotated by an angle a with respect to the neutral in the direction in which the universal joint portion 40 of the connecting member 36 approaches the intake valve 12 side by the drive mechanism 24. Further, the apex T of the cam 30 is located laterally from the center of the camshaft 28.

  In the first example, the second arm 16 has the base end 52 pulled to the left in the drawing by the universal joint 40 and moved to the left in the drawing, while the spring 38 is used to move the conversion member 18 to the second arm 16. Since the conversion member 18 is in close contact with the pad 25, the roller 56 is in contact with the cam 30 at the contact position B.

  In this first example, the angle r1 from the basic circle of the cam 30 to the point A where the cam crest starts and the contact position B where the roller 56 is in contact with the cam 30 is larger than in the other examples. Therefore, in this first example, even if the camshaft 28 rotates, the rotation angle until the roller 56 is actually driven by the cam 30 is large, and the driving phase of the second arm 16 is delayed.

  On the other hand, since the second arm 16 is moved to the left in the figure, the conversion member 18 is also moved to the left, and the conversion member 18 is opposed to the roller 50 at a portion where the conversion member 18 is thick. . Therefore, the gap between the conversion member 18 and the roller 50 is smaller than in the other examples, the camshaft 28 rotates, the second arm 16 swings, and the conversion member 18 is shown along the pad 25 as shown in FIG. The first arm 14 is immediately and greatly rotated via the roller 50. As a result, in the first example, the pressing amount of the intake valve 12 is large, and the intake passage 13 is opened widely. Therefore, as shown by a curve L1 in FIG. 9, the valve lift amount is large and the valve lift peak is retarded. In this example, the intake valve 12 is driven suitable for a state requiring a large intake amount at a high rotation and a high load.

  A second example in which the rocker shaft 22 is neutral is shown in FIGS. The second example corresponds to a state in which the universal joint portion 40 of the connection member 36 faces downward in the drawing, that is, an intermediate state between the first example and a third example described later. In the second example, the angle r2 between the point A where the cam crest starts and the point B where the roller 56 and the cam 30 contact each other is smaller than the first example, and the second arm 16 moves the cam 30 earlier than the first example. Driven by.

  On the other hand, since the second arm 16 is moved to the right in the drawing as compared with the first example, the conversion member 18 faces the roller 50 at a position where the thickness of the conversion member 18 is intermediate. Therefore, the gap formed between the conversion member 18 and the roller 50 is also intermediate between the first example and the third example described below, and the second arm 16 swings as shown in FIG. When 18 moves to the left in the drawing along the pad 25, the first arm 14 is rotated by an intermediate angle between the first and third examples via the roller 50 as shown in the drawing. As a result, in the second example, the intake valve 12 is pressed with a pressing amount corresponding to the middle between the first example and the third example, and the intake passage 13 is opened with a medium width. For this reason, as shown by the curve L2 in FIG. 9, the valve lift amount is medium and the valve drive phase is neutral, so that the intake valve 12 is driven in accordance with the intake amount of medium rotation and medium load.

  7 and 8 show a third example in which the rocker shaft 22 is rotated in the advance direction. In the third example, the rocker shaft 22 is rotated by an angle b in the direction in which the universal joint portion 40 of the connecting member 36 approaches the cam 30 side. In the third example, the angle r3 between the point A where the cam crest starts and the point B where the roller 56 and the cam 30 contact each other is set to be the narrowest, and the second arm 16 is driven by the cam 30 earlier than the second example. Is done.

  On the other hand, since the second arm 16 is moved further to the right in the drawing than in the second example, the conversion member 18 faces the roller 50 at a position where the thickness of the conversion member 18 is the thinnest. Therefore, the gap between the conversion member 18 and the roller 50 is wider than in the above two examples, and the second arm 16 swings and the conversion member 18 moves to the left in the drawing along the pad 25 as shown in FIG. Even so, the first arm 14 is rotated by the smallest angle as shown in the figure. Thus, in the third example, the intake valve 12 has a smaller pressing amount than the first example and the second example, and the intake passage 13 is opened most narrowly. Therefore, as indicated by a curve L3 in FIG. 9, the valve drive phase is advanced, the valve lift is reduced, and the intake valve 12 is driven suitable for a small intake amount with low rotation and low load.

  As described above, in the variable valve apparatus 10, when the rocker shaft 22 is rotated by the drive mechanism 24, the period when the angle is advanced with respect to the cam 30 of the second arm 16 is the roller 50 and the conversion member. Since it is canceled by the gap of 18, as shown in FIG. 9, the valve opening start timings of the three curves L 1, L 2 and L 3 having different valve lift amounts and valve lift peaks can be made substantially constant.

  Therefore, according to the variable valve operating apparatus 10, the valve closing timing can be changed while the valve opening start timing is fixed. Therefore, the valve closing timing is changed in accordance with the pulsation of the inertial intake air to increase the intake air amount. The effect of reducing fuel consumption can be obtained. Further, since the opening side of the intake valve 12 can be fixed and the closing side can be continuously changed, a high expansion ratio cycle can be achieved.

  In addition, fuel efficiency can be reduced by synergistic action with inertial intake. Inertial intake means that the pressure pulsation generated by the intake action of the piston causes inertia in the intake air in the intake pipe. By utilizing this inertial intake and starting to close the intake valve 12 at the peak time of intake pulsation, fresh air can continue to flow into the cylinder even after the piston passes the bottom dead center, and volume efficiency can be improved. . Since the peak time of pulsation varies depending on the engine speed, the intake air amount can be increased by setting the intake valve 12 to begin closing at the peak time by appropriately rotating the rocker shaft 22.

  Furthermore, in the case of the conventional general variable phase variable valve device, if the closing timing of the intake valve is retarded, the valve opening start timing is also retarded, and the valve overlap of intake and exhaust is reduced or eliminated. Loss occurs. On the other hand, according to the variable valve operating apparatus 10, the valve closing timing can be retarded while the valve opening start timing is fixed. Therefore, by delaying the valve closing timing while maintaining the valve overlap. The effect of increasing the amount of intake air can be obtained. For this reason, the effect of fuel consumption reduction is acquired.

  Optimum control of the amount of air results in a good combustion state, reducing unburned materials and the like and improving exhaust gas components. In general, the exhaust temperature becomes lower when the air is excessive at a low load. However, according to the variable valve operating apparatus 10, the amount of intake air can be controlled in accordance with the operating state of the engine. The exhaust temperature can be increased. For this reason, a catalyst is activated and a catalyst functions effectively. In this case, since the exhaust gas can be purified by the catalyst, the engine body can be set in a state where the fuel consumption is good even if the exhaust gas component is slightly deteriorated. Thereby, while improving the fuel consumption of an engine main body and purifying exhaust gas with a catalyst, both high fuel consumption and purification of exhaust gas can be achieved.

  Further, according to this variable valve operating apparatus 10, by reducing the intake air amount at low load, it is not necessary to provide an intake or exhaust throttle for controlling the intake air amount, and the cost can be reduced. In addition, by setting the second arm 16 to be able to advance with respect to the cam 30 from the state shown in FIG. 7, the cylinder resting state (valve lift amount is minimal or zero) shown in L4 of FIG. This can reduce fuel consumption.

  Further, FIG. 10 shows an example in which a guide member 27 is attached to the pad 25. The guide member 27 is provided on both sides of the pad 25, that is, on both sides along the moving direction of the conversion member 18. Thereby, the conversion member 18 is regulated so as not to be displaced in a direction perpendicular to the moving direction of the conversion member 18. The guide member 27 may be provided not only on both sides of the pad 25 but only on one side where the conversion member 18 is easy to move. Further, the guide member 27 is not attached to both sides of the pad 25, but the guide member 27 is attached to both sides of the guide surface portion directly provided on the arm portion 23, or the groove portion into which the conversion member 18 is slidably fitted is provided. It is good also as a guide member which forms in the arm part 23, makes the inside of a groove part a guide surface part, and raises the wall body raised on both sides of the groove part. Further, a guide member may be provided on the conversion member 18 and may be engaged with the pad 25 or the like by the guide member.

  Moreover, in the said example, although the lower surface 23a (guide surface part) of the arm part 23 and the lower surface of the pad 25 (sliding member) were formed in convex shape, this invention is not limited to this.

The perspective view which shows one Embodiment of the variable valve apparatus concerning this invention. The disassembled perspective view of the variable valve apparatus shown in FIG. The front view at the time of valve closing in the state which the phase of the variable valve apparatus shown in FIG. 1 retarded. The front view at the time of valve opening in the state which the phase of the variable valve apparatus shown in FIG. 1 retarded. The front view at the time of valve closing in the state where the phase of the variable valve apparatus shown in FIG. 1 is neutral. The front view at the time of valve opening in the phase of the variable valve apparatus shown in FIG. 1 in a neutral state. The front view at the time of valve closing in the state which the phase of the variable valve apparatus shown in FIG. 1 advanced. The front view at the time of valve opening in the state which the phase of the variable valve apparatus shown in FIG. 1 advanced. The figure which shows the relationship between the cam angle of a variable valve apparatus, and valve lift amount. The front view which showed the other example of the variable valve apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Variable valve apparatus 12 ... Intake valve 14 ... 1st arm 16 ... 2nd arm 18 ... Conversion member 20 ... Rocker shaft bracket 22 ... Rocker shaft 23 ... Arm part 24 ... Drive mechanism 25 ... Pad 26 ... Rocker arm mechanism 27 ... Guide member 28 ... Cam shaft 30 ... Cam 36 ... Connecting member 38 ... Spring 40 ... Universal joint portion 58 ... Sliding surface portion 60 ... Transmission surface portion

Claims (7)

A camshaft rotatably provided on a cylinder head of an internal combustion engine;
A rocker shaft rotatably provided in the internal combustion engine;
A rocker arm mechanism that is driven by a cam formed on the camshaft and opens and closes at least one of an intake valve and an exhaust valve;
The rocker arm mechanism is
A first arm that is swingably supported by the rocker shaft and configured to drive the valve;
A second arm driven by the cam and provided so as to be swingable about a fulcrum provided on the rocker shaft side;
A conversion member that is provided between the first arm and the second arm and transmits the swing displacement of the second arm to the first arm to drive the first arm;
A drive mechanism for rotating the rocker shaft and displacing the fulcrum;
The displacement of the fulcrum by the drive mechanism moves the contact portion of the second arm with the cam along the circumferential direction of the base circle of the cam and changes the drive phase of the second arm with respect to the cam. A variable valve operating apparatus for an internal combustion engine characterized by the above. The driving phase of the second arm continuously changes in accordance with an angle formed by a position where the peak of the cam starts from a base circle of the cam and a contact position between the second arm and the cam. The variable valve operating apparatus for an internal combustion engine according to claim 1. The conversion member includes a sliding surface portion that slides along a guide surface portion of a cylinder head side member provided in the cylinder head, and the conversion member is moved along the sliding surface portion by a swinging operation of the second arm. A sliding surface portion that contacts the first arm when it slides and drives the first arm;
The transmission surface portion rotates the rocker shaft by the drive mechanism to displace the fulcrum, thereby continuously changing the drive phase of the intake valve or the exhaust valve according to the movement amount of the second arm. 2. The variable valve operating apparatus for an internal combustion engine according to claim 1 , wherein the variable valve operating apparatus is configured to change. The fulcrum is formed by a connecting member provided on the rocker shaft,
In the second arm, a base end portion provided on one end side of the second arm is rotatably supported by the connection member, and an abutting portion provided on the other end side of the second arm is the conversion member. And a part of the second arm is in contact with the cam, and a spring provided on the rocker shaft is engaged with the conversion member, and the second arm is moved through the conversion member. 3. The variable valve operating apparatus for an internal combustion engine according to claim 1 , wherein the variable valve operating apparatus is biased toward the cam. The sliding member is provided between the sliding surface portion and the guide surface portion, and the sliding surface portion and the guide surface portion are slidably in contact with each other through the sliding member. A variable valve operating device for an internal combustion engine. 6. The variable valve operating apparatus for an internal combustion engine according to claim 5 , wherein the cylinder head side member is fixed to a rocker shaft bracket that rotatably holds the rocker shaft. Said guide member for guiding said conversion member to the cylinder head side member is provided, according to claim 6 that has been characterized for restricting the movement of the conversion member in the direction perpendicular to the sliding direction of said conversion member by the guide member A variable valve operating apparatus for an internal combustion engine according to claim 1.

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