JP4185868B2 - Variable valve mechanism - Google Patents

Description

  The present invention relates to a variable valve mechanism, and more particularly to a variable valve mechanism for an internal combustion engine that can change the operating angle and / or lift amount of a valve body that opens and closes in synchronization with the rotation of a camshaft.

  Conventionally, as disclosed in, for example, Japanese Patent Application Laid-Open No. 2002-371816, a variable valve mechanism that includes a mechanism that changes a working angle and a lift amount of a valve body between a cam and a valve body is known. The variable valve mechanism includes a first intervening arm that transmits the pressing force of the cam to the rocker arm, and a second intervening arm that abuts the first intervening arm and swings the swing range according to the rotational position of the control shaft. And. In this mechanism, when the swing range of the second intervening arm changes according to the rotational position of the control shaft, the timing at which the first intervening arm pushes down the valve body via the rocker arm and the push-down amount of the valve body change. For this reason, according to the conventional variable valve mechanism, the operating angle and lift amount of the valve body can be continuously changed by controlling the rotational position of the control shaft. In this conventional mechanism, a single rocker arm is shared by two valve bodies.

JP 2002-371816 A

  By the way, in a valve mechanism that has a rocker arm for each single valve body, in order to realize a variable valve mechanism that has the above functions, a contact surface that receives the pressing force of the cam is arranged in the center. Then, a valve operating mechanism including a swinging member that arranges pressing portions that transmit the pressing force to the respective rocker arms on both sides of the abutting surface can be considered.

  In the above valve operating mechanism, it is necessary to make the operating angle and the lift amount the same between the plurality of valve bodies with high accuracy, and therefore it is necessary to maintain the manufacturing accuracy, processing accuracy, and assembly accuracy of the swing member high. On the other hand, when the contact surface of the swinging member and the pressing portion are configured integrally, the shape may be complicated, and thus productivity may be reduced. Further, when a change with the passage of time occurs for each valve body, it is not efficient to replace the entire swinging member manufactured with labor and time as described above during maintenance.

  The present invention has been made to solve the above-described problems, and improves productivity, and further improves work efficiency for suppressing variation in valve operating angle and / or lift amount. An object of the present invention is to provide a variable valve mechanism that can be used.

In order to achieve the above object, a first invention is a variable valve mechanism having a function of changing a working angle and / or a lift amount of a valve body,
A control shaft whose position is adjusted to change the operating angle and / or lift amount of the valve body within a predetermined variable range;
A swinging member that is interposed between the cam and the valve body and swings in synchronization with the rotation of the cam to transmit the pressing force of the cam to the valve body;
A variable mechanism that changes a relative angle of the swing member with respect to the valve body according to a position of the control shaft,
The swing member has a central arm that receives the pressing force of the cam transmitted from the variable mechanism, and a swing arm that transmits the pressing force to the valve body ,
The swing member is configured by dividing the central arm and the swing arm, and the central arm and the swing arm are integrated by being connected by a connecting pin. And

  According to a second aspect of the present invention, in the first aspect, the swing member is provided with the swing arm on both sides of the central arm.

According to a third aspect of the present invention, in the first or second aspect of the invention, the central arm includes a first bearing portion rotatably supported on the control shaft, and the control shaft from the first bearing portion. A projecting surface provided in a radial direction, and a contact surface with which the variable mechanism abuts,
The swing arm is provided with a second bearing portion rotatably supported by the control shaft, and protrudes from the second bearing portion in the radial direction of the control shaft, and the cam pressing force is applied to the valve. A pressing portion that is transmitted to the body,
The center arm and the swing arm are within a range sandwiched between the position of the base of the abutment surface in the first bearing portion and the position of the base of the pressing portion in the second bearing portion. It is connected by.

  According to the first invention, only an inexpensive swing arm can be exchanged. And according to this invention, the fluctuation | variation of the working angle of a valve body and / or a lift amount can be suppressed by replacement | exchange of a rocking | fluctuating arm. In addition, according to the present invention, since the machining can be performed with a single swing arm, the machining operation is facilitated. Therefore, the above-described variation can be easily suppressed even by processing the swing arm.

  According to the second invention, by exchanging the swing arm, it is possible to suppress variation in the operating angle and / or lift amount of the valve body between the two valve bodies.

  According to the third invention, the central arm and the swing arm can be effectively coupled to each other by the connecting pin at a position where their coupling rigidity can be increased. For this reason, according to the present invention, the rigidity of the swing member can be ensured while minimizing the increase in weight with respect to the structure in which the central arm and the swing arm are integrally formed.

  Embodiments of the present invention will be described below with reference to the drawings. In addition, the same code | symbol is attached | subjected to the element which is common in each figure, and the overlapping description is abbreviate | omitted.

Embodiment 1 FIG.
[Configuration of variable valve mechanism]
FIG. 1 is a perspective view of a main part of a variable valve mechanism 10 according to Embodiment 1 of the present invention. The variable valve mechanism shown in FIG. 1 is a mechanism for driving a valve body of an internal combustion engine. Here, it is assumed that each cylinder of the internal combustion engine is provided with two intake valves and two exhaust valves. The configuration shown in FIG. 1 functions as a mechanism for driving two intake valves or two exhaust valves arranged in a single cylinder.

  The configuration shown in FIG. 1 includes two valve bodies 12 that function as intake valves or exhaust valves. A valve shaft 14 is fixed to each valve body 12. The end of the valve shaft 14 is in contact with a pivot provided at one end of the rocker arm 16. A biasing force of a valve spring (not shown) acts on the valve shaft 14, and the rocker arm 16 is biased upward by the valve shaft 14 that has received the biasing force. The other end of the rocker arm 16 is rotatably supported by a hydraulic lash adjuster 18. According to the hydraulic lash adjuster 18, the tappet clearance can be automatically adjusted by automatically adjusting the position in the height direction of the rocker arm by hydraulic pressure.

  A rocker roller 20 is disposed at the center of the rocker arm 16. A rocking arm 22 is disposed on the top of the rocker roller 20. Hereinafter, the structure around the swing arm 22 will be described with reference to FIG.

  FIG. 2 is an exploded perspective view of the swing member 24 and the arm member 26. The swing member 24 and the arm member 26 are both main components in the configuration shown in FIG. The swing arm 22 described above is one of the members constituting the swing member 24 as shown in FIG.

  That is, as shown in FIG. 2, the swing member 24 includes two swing arms 22 and a central arm 27 sandwiched between them separately. The central arm 27 is provided with a roller contact surface 28. The two swing arms 22 are provided corresponding to the two valve bodies 12, respectively, and are in contact with the rocker roller 20 (see FIG. 1) described above.

  The central arm 27 and the two swing arms 22 are provided with bearing portions 29 and 30, respectively. These bearing portions 29 and 30 are opened so as to penetrate through the central arm 27 and the swing arm 22 in a combined state. Each of the swing arms 22 is provided with a concentric circle portion 32 and a pressing portion 34 on the surface in contact with the rocker roller 20. The concentric circle portion 32 is provided such that the contact surface with the rocker roller 20 forms a concentric circle with the bearing portion 30. On the other hand, the pressing portion 34 is provided such that the distance from the center of the bearing portion 30 increases as the distal end portion thereof is increased.

  FIG. 3 is a diagram for explaining the configuration of the swing member 24 used in the present embodiment. More specifically, FIG. 3A is an exploded perspective view of the oscillating member 24, and FIG. 3B is a side view of the oscillating member 24 as shown by an arrow B shown in FIG. FIG. An arm contact surface 27 a that contacts the swing arm 22 is formed on the bearing portion 29 of the central arm 27. Correspondingly, the bearing portions 30 of the two swing arms 22 are respectively formed with arm contact surfaces 22a that overlap the arm contact surfaces 27a. Further, the swing member 24 of this embodiment includes a connecting pin 33 for connecting the central arm 27 and the two swing arms 22. On the arm contact surfaces 27a and 22a of the central arm 27 and the swing arm 22, respectively, pin through holes 27b and 22b through which the connecting pins 33 are inserted are provided. By coupling with the connecting pin 33, it is possible to restrict the relative rotation between the central arm 27 and the two swing arms 22. Further, as shown in FIG. 3B, the connecting pin 33 is attached at a position close to the roller contact surface 28 of the central arm 27 and close to the pressing portion 34 of the swing arm 22. It has been.

  Next, the arm member 26 will be described with reference to FIG. As shown in FIG. 2, the arm member 26 includes a non-oscillating portion 36 and an oscillating roller portion 38. The non-oscillating part 36 is provided with a through hole, and the control shaft 40 is inserted into the through hole. Furthermore, a fixing pin 42 is inserted into the non-oscillating portion 36 and the control shaft 40 to fix the relative positions of both. For this reason, the non-oscillating part 36 and the control shaft 40 function as an integral structure.

  The swing roller unit 38 includes two side walls 44. These side walls 44 are connected to a non-oscillating portion 36 through a rotation shaft 46 so as to be rotatable. A cam contact roller 48 and a slide roller 50 are disposed between the two side walls 44. The cam contact roller 48 and the slide roller 50 can freely rotate while being sandwiched between the side walls 44.

  The control shaft 40 described above is a member that is rotatably held by a cylinder head (not shown), and the swing member 24 is a member that is held by the control shaft 40 via bearing portions 29 and 30. That is, the control shaft 40 is a member that should be integrated with the non-oscillating portion 36 in a state of being inserted into the bearing portions 29 and 30. In order to satisfy this requirement, the non-oscillating portion 36 (that is, the arm member 26) is positioned between the central arm 27 of the oscillating member 24 before being fixed to the control shaft 40. The control shaft 40 is inserted so as to pass through the bearing portions 29 and 30 and the non-oscillating portion 36 in a state where the alignment is performed. Thereafter, a fixing pin 42 is attached to fix the control shaft 40 and the non-oscillating portion 36. As a result, the oscillating member 24 (the oscillating arm 22 and the central arm 27) can freely rotate around the control shaft 40, the non-oscillating portion 36 is integrated with the control shaft 40, and is oscillated. A mechanism in which the roller portion 38 can swing with respect to the non-oscillating portion 36 is realized.

  When the rocking member 24 and the arm member 26 are assembled as described above, the relative angle between the rocking member 24 and the control shaft 40, that is, the relative angle between the rocking member 24 and the non-oscillating portion 36 is as follows. As long as the predetermined condition is satisfied, the slide roller 50 of the swing roller unit 38 can contact the roller contact surface 28 of the swing member 24. When the swing member 24 is rotated around the control shaft 40 within a range that satisfies the predetermined condition while maintaining the contact between both, the slide roller 50 rolls along the roller contact surface 28. can do. The variable valve mechanism of the present embodiment opens and closes the valve body 12 with its rolling. The operation will be described in detail later with reference to FIG. 4 and FIG.

  FIG. 1 shows a state in which the swing member 24, the arm member 26, and the control shaft 40 are assembled according to the above procedure. In this state, the positions of the swing member 24 and the arm member 26 are regulated by the position of the control shaft 40. The control shaft 40 is fixed to a fixing member such as a cylinder head via a bearing (not shown) so that the above-described conditions are satisfied, that is, the rocker roller 20 of the rocker arm 16 is in contact with the swing arm 22. ing.

  An actuator (not shown) is connected to the control shaft 40. This actuator can rotate the control shaft 40 within a predetermined angle range. The state shown in FIG. 1 shows a state in which the rotation angle of the control shaft 40 is adjusted to a range that satisfies the above-described predetermined condition by the actuator, and the slide roller 50 is brought into contact with the roller contact surface 28. Yes.

  The variable valve mechanism 10 of this embodiment also includes a camshaft 52 that rotates in synchronization with the crankshaft. A cam 54 provided for each cylinder of the internal combustion engine is fixed to the camshaft 52. In the state shown in FIG. 1, the cam 54 is in contact with the cam contact roller 48 and restricts the upward movement of the swing roller portion 38. That is, in the state shown in FIG. 1, the roller contact surface 28 of the swing member 24 is mechanically connected to the cam 54 via the cam contact roller 48 and the slide roller 50 of the swing roller portion 38. It has been realized.

  According to the state described above, when the cam nose presses the cam contact roller 48 as the cam 54 rotates, the force is transmitted to the roller contact surface 28 via the slide roller 50. The slide roller 50 can continue to transmit the acting force of the cam 54 to the swing member 24 while rolling on the roller contact surface 28. As a result, the swing member 24 rotates around the control shaft 40, the rocker arm 16 is pushed down by the swing arm 22, and the valve body 12 is given a movement in the valve opening direction. As described above, the variable valve mechanism 10 can actuate the valve body 12 by transmitting the acting force of the cam 54 to the roller contact surface 28 via the cam contact roller 48 and the slide roller 50. it can.

[Operation of variable valve mechanism]
Next, the operation of the variable valve mechanism 10 according to Embodiment 1 of the present invention will be described with reference to FIGS.

  The variable valve mechanism 10 configured as described above is configured so that the cam 54 and the roller contact surface 28 are mechanically connected via the cam contact roller 48 and the slide roller 50 in order to maintain the lost state. A motion spring 56 is provided. As shown in FIGS. 4 and 5, the lost motion spring 56 biases the rear end portion of the roller contact surface 28 in a state where the upper end of the lost motion spring 56 is fixed to the cylinder head or the like. The urging force of the lost motion spring 56 acts as a force that the roller contact surface 28 urges the slide roller 50 upward, and further as a force that presses the cam contact roller 48 against the cam 54. As a result, the variable valve mechanism 10 can maintain a state in which the cam 54 and the roller contact surface 28 are mechanically connected as shown in FIG. 4 or FIG.

  FIG. 4 shows a state in which the variable valve mechanism 10 operates to give a small lift to the valve body 12. Hereinafter, this operation is referred to as “small lift operation”. More specifically, FIG. 4A shows a state in which the valve body 12 is closed during the small lift operation, and FIG. 4B shows that the valve body 12 is opened during the small lift operation. The state of speaking is shown respectively.

In FIG. 4A, the symbol θ _C is a parameter that represents the rotational position of the control shaft 40. Hereinafter, the parameter is referred to as “control shaft rotation angle θ _C ”. Here, for the sake of convenience, an angle formed by the axial direction of the fixing pin 42 that fixes the control shaft 40 and the non-oscillating portion 36 and the vertical direction is defined as a control shaft rotation angle θ _C. In FIG. 4A, the symbol θ _A is a parameter representing the rotational position of the swing arm 22. Hereinafter, the parameter is referred to as “arm rotation angle θ _A ”. For convenience, and to define the angle between the straight line and the horizontal direction connecting the center of the tip portion and the control shaft 40 of the swing arm 22 and the arm rotation angle theta _A.

In the variable valve mechanism 10, the rotation position of the swing arm 22, that is, the arm rotation angle θ _A is determined by the position of the slide roller 50. Further, the position of the slide roller 50 is determined by the position of the rotating shaft 46 of the swing roller unit 38 and the position of the cam contact roller 48. In the range where the contact between the cam contact roller 48 and the cam 54 is maintained, as the rotation shaft 46 rotates counterclockwise in FIG. 4, that is, as the control shaft rotation angle θc increases, the slide roller 50 increases. The position changes upward. Therefore, in the variable valve mechanism 10, the larger the control shaft rotation angle theta _C is, a phenomenon occurs that the arm rotation angle theta _A decreases.

In the state shown in FIG. 4A, the control shaft rotation angle θ _C is within a range in which the cam contact roller 48 can maintain contact with the cam 54, that is, the cam 54 moves upward of the cam contact roller 48. It is almost the maximum value that can be regulated. Therefore, in the state shown in FIG. 4A, the arm rotation angle θ _A is almost the minimum value. In this case, the variable valve mechanism 10 is configured such that the substantially center of the concentric circular portion 32 of the swing arm 22 is in contact with the rocker roller 20 of the rocker arm 16 and, as a result, the valve body 12 is closed. Yes. Hereinafter, the arm rotation angle θ _A in this case is referred to as “reference arm rotation angle θ _A0 during small lift”.

When the cam 54 rotates from the state shown in FIG. 4A, the cam contact roller 48 is pressed by the cam nose and moves in the direction of the control shaft 40 as shown in FIG. 4B. Since the distance from the rotation shaft 46 to the slide roller 50 of the oscillating roller portion 38 does not change, the roller contact surface 28 rolls on the surface when the cam contact roller 48 approaches the control shaft 40. It is pushed down by the slide roller 50. As a result, the swing arm 22 is rotated in the direction of arm rotation angle theta _A increases, the contact point between the swing arm 22 and rocker roller 20, moves from the concentric portion 32 to the pressing portion 34.

In the small lift operation, the reference arm rotation angle θ _A0 is set to a small value as described above. Therefore, the maximum value of the arm rotation angle theta _A due to the rotation of the cam 54 also becomes a relatively small value in the case of the small lift operation. Hereinafter, the maximum value is referred to as “maximum arm rotation angle θ _AMAX during small lift”. The valve body 12 has a maximum lift when the arm rotation angle θ _A reaches the maximum arm rotation angle θ _AMAX . As shown in FIG. 4B, the variable valve mechanism 10 has a slight contact portion between the rocker roller 20 and the swing arm 22 when the maximum arm rotation angle θ _AMAX during a small lift occurs. 34, and as a result, a slight lift is generated in the valve body 12. Therefore, according to the variable valve mechanism 10, a small lift can be given to the valve body 12 in synchronization with the rotation of the cam 54 by performing the small lift operation described above.

  In this case, the period during which the acting force of the cam 54 actually pushes down the valve body 12, that is, the period during which the valve body 12 is not closed as the cam 54 rotates (crank angle width) is also relatively small. (This period is hereinafter referred to as “working angle”). Therefore, according to the variable valve mechanism 10, the operating angle of the valve body 12 can be reduced by performing a small lift operation.

  FIG. 5 shows a state in which the variable valve mechanism 10 is operated so as to give a large lift to the valve body 12. Hereinafter, this operation is referred to as “large lift operation”. More specifically, FIG. 5A shows a state in which the valve body 12 is closed in the process of the large lift operation, and FIG. 5B shows a state in which the valve body 12 is opened in the process of the large lift operation. The state of speaking is shown respectively.

When performing a large lift operation, as shown in FIG. 5A, the control shaft rotation angle θ _C is adjusted to a sufficiently small value. As a result, when the large lift operation is performed, the arm rotation angle θ _A when not lifted, that is, the reference arm rotation angle θ _A0 is set to a sufficiently large value within a range in which the slide roller 50 does not fall off the roller contact surface 28. The The variable valve mechanism 10 is configured such that the contact point between the swing arm 22 and the rocker roller 20 is located at the end of the concentric circle portion 32 at the reference arm rotation angle θ _A0 . For this reason, the valve body 12 is maintained in the closed state even in the case of the large lift operation.

When the cam 54 from the state shown in FIG. 5 (A) is rotated, as shown in FIG. 5 (B), the cam contact roller 48 is pressed against the cam nose, rocking in a direction arm rotation angle theta _A increases The moving arm 22 rotates. As a result, the contact point between the swing arm 22 and the rocker roller 20 shifts from the concentric circle portion 32 to the pressing portion 34. In the case of the large lift operation, the reference arm rotation angle θ _A0 is set to a large value as described above. Therefore, the maximum arm rotation angle θ _AMAX generated along with the rotation of the cam 54 is also set to a large value. As shown in FIG. 5 (B), the variable valve mechanism 10 has a sufficient contact point between the rocker roller 20 and the swing arm 22 when the maximum arm rotation angle θ _AMAX occurs. It is comprised so that it may become the position which entered 34. Therefore, according to the variable valve mechanism 10, a large lift and a large working angle can be given to the valve body 12 in synchronization with the rotation of the cam 54 by performing the large lift operation described above.

  When the variable valve mechanism 10 of the present embodiment performs the above-described operation and the pressing force of the cam 54 is transmitted to the swing arm 22 to push down the valve body 12, the pressing portion 34 of the swing arm 22 The urging force of the valve spring is input so as to resist the pressing force. Since the roller contact surface 28 is mechanically connected to the cam 54 via the cam contact roller 48 and the slide roller 50, a valve spring is provided between the roller contact surface 28 and the pressing portion 34. Torque around the control shaft 40 is exerted by the urging force. The two swing arms 22 and the central arm 27 are coupled by a connecting pin 33.

  The connecting pin 33 can be attached within the range of the arm contact surfaces 22a and 27a where the swing arm 22 and the central arm 27 overlap. In order to connect the swing arm 22 and the central arm 27 with high rigidity, the distance from the force point of the urging force in the pressing portion 34 to the connection point by the connection pin 33 and the roller contact surface 28 from the connection point. It is desirable that the distance to the point of application of the urging force is short. Further, the torque acts as a shearing force on the connecting pin 33. In order to reduce this shearing force, it is desirable that the position of the connecting pin 33 be far from the control shaft 40.

  As described above, in the variable valve mechanism 10 of the present embodiment, the connecting pin 33 is attached at a position close to the roller contact surface 28 and close to the pressing portion 34 (see FIG. 3 (B)). For this reason, according to the variable valve mechanism 10 of the present embodiment, the swing member 24 can obtain high coupling rigidity. Moreover, the shearing force which acts on the connecting pin 33 can be made small by setting it as the above structures. For this reason, according to the mechanism of the present embodiment, the pin can be reduced in diameter, and the rigidity of the swing member 24 can be sufficiently ensured while minimizing the weight increase with respect to the integrally molded product.

  As described above, in the variable valve mechanism 10 of the present embodiment, the swing arm 22 having the pressing portion 34 and the central arm 27 having the roller contact surface 28 are configured separately. For this reason, the remarkable effect shown below can be acquired.

  That is, according to the variable valve mechanism 10 of the present embodiment, only the swing arm 22 can be replaced. In the mechanism of this embodiment, the valve opening operation of the valve body 12 is started as the swing arm 22 rotates and the contact point with the rocker roller 20 shifts from the concentric circle portion 32 to the pressing portion 34. The timing at which the valve opening operation of the valve body 12 is started and the amount by which the valve body 12 is pushed down can be adjusted by changing the profile of the pressing portion 34 of the swing arm 22. That is, the working angle and lift amount of the valve body 12 can be changed by changing the profile of the pressing portion 34 of the swing arm 22. For this reason, according to the variable valve mechanism 10 of the present embodiment, it is possible to easily suppress variations in the operating angle and the lift amount between the valve bodies 12 by replacing only the inexpensive swing arm 22.

  Further, according to the variable valve mechanism 10 of the present embodiment, when the two valve bodies 12 driven by the same variable valve mechanism 10 are changed over time to different degrees, only the swing arm 22 is replaced. Thus, the variation between these two valve bodies 12 can be adjusted. Furthermore, according to the mechanism of the present embodiment, machining by the swing arm 22 alone becomes possible, which facilitates the machining operation. For this reason, according to this mechanism, the variation between the two valve bodies 12 can be easily suppressed even by processing the swing arm 22.

  Further, in the variable valve mechanism 10 of the present embodiment, as described above, the roller contact surface 28 and the pressing portion 34 are arranged so as to overlap each other when viewed from the axial direction of the control shaft 40 (FIG. 3B )reference). For this reason, much labor and time are required for grinding the swing arm 22 and the central arm 27. On the other hand, according to the mechanism of the present embodiment, the swing arm 22 and the central arm 27 can be processed independently, and each part can be processed easily. Furthermore, it becomes possible to perform surface grinding at a time in a state where a plurality of the swing arms 22 are stacked, and productivity can be improved.

  Further, according to the variable valve mechanism 10 of the present embodiment, the substantial distance between the two valve bodies 12 can be changed by changing the thickness of the swing arm 22. For this reason, according to the variable valve mechanism 10 of the present embodiment, it is possible to cope with a layout in which the interval between the two valve bodies is different by changing the inexpensive swing arm 22.

In the first embodiment described above, the control shaft 40 is adjusted in its rotational position (control shaft rotation angle θ _C ), but the operating angle and / or lift amount of the valve body are within a predetermined variable range. The control axis whose position is adjusted in order to change the position is not limited to this. For example, the control axis may be movable in the axial direction, and the movement amount may be adjusted.

In the first embodiment described above, the arm member 26 corresponds to the “variable mechanism” in the first invention.
In the first embodiment described above, the bearing portion 29 and the bearing portion 30 correspond to the “first bearing portion” and the “second bearing portion” in the second invention, respectively.

Embodiment 2. FIG.
Next, a second embodiment of the present invention will be described with reference to FIG.
FIG. 6 is a view for explaining the configuration of the variable valve mechanism 60 of the present embodiment. In the variable valve mechanism 60 of the present embodiment, the position of the roller contact surface 66 of the central arm 64 is separated from the pressing portion 34 of the swing arm 22 as the positional relationship between the cam 62 and the valve element is different. The configuration is the same as that of the first embodiment except that the layout is the layout. That is, in the variable valve mechanism 60, only the central arm 64 is changed to a different one corresponding to the layout change. According to such a configuration, the swing arm 22 can be shared only by changing the coupling position of the connecting pin 33.

  In the variable valve mechanism 60 of the present embodiment, as shown in FIG. 6, the roller contact surface 66 is provided so as to protrude from the bearing portion 68 of the central arm 64. The pressing portion 34 is provided so as to protrude from the bearing portion 30 of the swing arm 22. The central arm 64 and the swing arm 22 are overlapped by bearing portions 68 and 30. The connecting pin 33 is attached so as to penetrate the base portion of the roller contact surface 66.

  According to the configuration as described above, the distance from the point of application of the urging force by the valve spring on the roller contact surface 66 to the connection point by the connection pin 33 can be reduced, and the urging force at the pressing portion 34 from the connection point. The distance to the power point can be made relatively small. For this reason, according to the variable valve mechanism 60 of the present embodiment, the central arm 64 and the swing arm 22 can be coupled with high rigidity. In addition, in the above-described configuration, the swing arm 22 and the central arm 27 are connected at a position closer to the roller contact surface 66 than the pressing portion 34. For this reason, it is possible to give higher rigidity especially to the periphery of the roller contact surface 66.

  By the way, in Embodiment 2 mentioned above, the connection point by the connection pin 33 was made into the base part of the roller contact surface 66, but the suitable connection position by the connection pin 33 is the said urging | biasing force in the press part 34. Both the distance from the force point to the connection point by the connection pin 33 and the distance from the connection point to the point of application of the urging force on the roller contact surface 66, or a position where the sum of these distances becomes short. I just need it. For this reason, the position of the connection point may be within a range (a range indicated by an arrow in FIG. 6) sandwiched between the base position of the roller contact surface 66 and the base position of the pressing portion 34.

It is a perspective view of the principal part of the variable valve mechanism of Embodiment 1 of this invention. It is a disassembled perspective view of the rocking | swiveling member and arm member which are the components of the variable valve mechanism shown in FIG. It is a figure for demonstrating the structure of the rocking | swiveling member used in Embodiment 1 of this invention. It is a figure which shows a mode in case the variable valve mechanism shown in FIG. 1 performs a small lift operation | movement. It is a figure which shows a mode in case the variable valve mechanism shown in FIG. 1 performs a big lift operation | movement. It is a figure for demonstrating the structure of the variable valve mechanism of Embodiment 2 of this invention.

Explanation of symbols

10, 60 Variable valve mechanism 12 Valve body 16 Rocker arm 22 Swing arm 24 Swing member 26 Arm member 27, 64 Central arm 28, 66 Roller contact surface 29, 30, 68 Bearing portion 32 Concentric circle portion 33 Connecting pin 34 Pressing portion 36 Non-oscillating portion 38 Oscillating roller portion 40 Control shaft 46 Rotating shaft 48 Cam contact roller 50 Slide roller 54, 62 Cam θ _C Control shaft rotation angle θ _A Arm rotation angle

Claims (3)

A variable valve mechanism having a function of changing a working angle and / or a lift amount of a valve body,
A control shaft whose position is adjusted to change the operating angle and / or lift amount of the valve body within a predetermined variable range;
A swinging member that is interposed between the cam and the valve body and swings in synchronization with the rotation of the cam to transmit the pressing force of the cam to the valve body;
A variable mechanism that changes a relative angle of the swing member with respect to the valve body according to a position of the control shaft,
The swing member has a central arm that receives the pressing force of the cam transmitted from the variable mechanism, and a swing arm that transmits the pressing force to the valve body ,
The swing member is configured by dividing the central arm and the swing arm, and the central arm and the swing arm are integrated by being connected by a connecting pin. Variable valve mechanism.
  The variable valve mechanism according to claim 1, wherein the swinging member has the swinging arm disposed on each side of the central arm. The central arm is provided with a first bearing portion rotatably supported by the control shaft, and a contact projecting from the first bearing portion in a radial direction of the control shaft, with which the variable mechanism abuts. With a surface,
The swing arm is provided with a second bearing portion rotatably supported by the control shaft, and protrudes from the second bearing portion in the radial direction of the control shaft, and the cam pressing force is applied to the valve. A pressing portion that is transmitted to the body,
The center arm and the swing arm are within a range sandwiched between the position of the base of the contact surface in the first bearing portion and the position of the base of the pressing portion in the second bearing portion. The variable valve operating mechanism according to claim 1, wherein the variable valve operating mechanism is connected to each other.

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