JP2005226540A - Variable movable valve mechanism - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily replace a roller having influence on a working angle and/or a lift quantity of a valve element in a variable movable valve mechanism. <P>SOLUTION: This variable movable valve mechanism has a control shaft for adjusting a rotational position for changing the working angle and the lift quantity of the valve element; and has a slide roller 50 for transmitting pressing force of a cam to the valve element via a roller abutting surface 28 in a state of abutting on the roller abutting surface 28; and has a roller arm 44 for rotatably supporting the slide roller 50 and having a roller bearing hole 44b opened on the side where the slide roller 50 abuts on the roller abutting surface 28. The variable valve train is constituted so that when a control shaft turning angle θ<SB>C</SB>falls within an ordinary use range, the slide roller 50 abuts on the roller abutting surface 28, and when the control shaft rotates up to an area exceeding the ordinary use range of the control shaft turning angle θ<SB>C</SB>, the slide roller 50 and the roller abutting surface 28 become an unabutting state. <P>COPYRIGHT: (C)2005,JPO&NCIPI

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 (swinging arm) that transmits a pressing force of the cam to push the valve body between the cam and the valve body, and a second intervening arm having a roller that contacts the cam. (Swinging roller part). The variable valve mechanism is configured such that the positional relationship between the cam and the roller changes according to the rotational position of the control shaft. When the positional relationship between the cam and the roller changes, the timing at which the first intervening arm pushes down the valve body and the push-down amount of the valve body with respect to the rotation of the cam can be changed. For this reason, according to the conventional variable valve mechanism, the operating angle and the lift amount of the valve body can be continuously changed by controlling the rotational position of the control shaft.

JP 2002-371816 A

  As described above, the roller affects the change in the working angle and lift amount of the valve body in accordance with the relative positional relationship with the cam. Therefore, in the mechanism having such a roller, the working angle of the valve element and the lift amount can be finely adjusted by changing the diameter of the roller. For this reason, in the variable valve mechanism, it is convenient that the roller that affects the operating angle and / or the lift amount of the valve body as described above can be easily replaced during assembly and maintenance.

  The present invention has been made to solve the above-described problems, and provides a variable valve mechanism that can easily replace a roller that affects the operating angle and / or lift amount of a valve body. Objective.

In order to achieve the above object, the first invention provides a control shaft, the position of which is adjusted so as to change the operating angle and / or lift amount of the valve body within a predetermined variable range, and the cam and the valve body. A variable valve mechanism that includes a transmission mechanism that is interposed between and transmits the pressing force of the cam to the valve body,
The transmission mechanism has a function of changing the operating angle and / or the lift amount according to the position of the control shaft, and a roller for transmitting the pressing force of the cam to the valve body in a state of contact with the contact member. A roller bearing hole that rotatably supports the roller and is opened on a side where the roller contacts the contact member;
When the position of the control shaft is within the normal use range, the roller and the contact member abut, and when the control shaft is displaced to a region exceeding the normal use range, the roller and the The contact member may be in a non-contact state.

In a second aspect based on the first aspect, the roller includes a roller shaft detachably inserted into the roller.
The roller bearing holes are arranged in a pair at both ends of the roller shaft,
The roller shaft is characterized in that a diameter of a portion interposed between the pair of roller bearing holes is larger than a diameter of a portion inserted into the pair of roller bearing holes.

  According to a third aspect of the present invention, in the first or second aspect, the control shaft extends beyond the normal use range to a position where the cam and the transmission mechanism do not come into contact with each other when mounted on the internal combustion engine. In the case of displacement, the roller and the contact member are not in contact with each other.

  According to the first invention, when the position of the control shaft is within the normal use range, the roller can move without being detached from the roller bearing hole, and the control shaft is displaced to an area exceeding the normal use range. By doing so, the roller can be made detachable from the roller bearing hole. For this reason, according to the present invention, the roller can be easily replaced during assembly or maintenance.

  According to the second aspect of the present invention, it is possible to prevent the roller shaft from moving in the axial direction and coming out of the roller bearing hole during engine operation without adding a roller shaft removal preventing member.

  According to the third aspect of the invention, in a state where the variable valve mechanism is mounted on the internal combustion engine, the roller can be easily replaced by displacing the control shaft to a position where the cam and the transmission mechanism do not contact each other. it can.

  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 first arm member 24 and the second arm member 26. The first arm member 24 and the second arm member 26 are both main components in the configuration shown in FIG. The swing arm 22 described above is a part of the first arm member 24 as shown in FIG.

  That is, as shown in FIG. 2, the first arm member 24 is a member integrally including two swing arms 22 and a roller contact surface 28 sandwiched between them. 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 first arm member 24 is provided with a bearing portion 30 that is open so as to penetrate the two swing arms 22. 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.

  The second 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 roller arms 44. These roller arms 44 are connected to the non-oscillating portion 36 through a rotating shaft 46 so as to be rotatable. A cam contact roller 48 and a slide roller 50 are disposed between the two roller arms 44. These roller arms 44 are provided with a cam contact roller bearing hole 44a and a slide roller bearing hole 44b for rotatably supporting the cam contact roller 48 and the slide roller 50, respectively. Therefore, the cam contact roller 48 and the slide roller 50 can freely rotate while being sandwiched between the roller arms 44.

  The control shaft 40 described above is a member that is rotatably held by a cylinder head (not shown), and the first arm member 24 is a member that is held by the control shaft 40 via the bearing portion 30. That is, the control shaft 40 is a member that should be integrated with the non-oscillating portion 36 while being inserted into the bearing portion 30. In order to satisfy this requirement, the non-oscillating portion 36 (that is, the second arm member 26) is positioned between the two oscillating arms 22 of the first arm member 24 before being fixed to the control shaft 40. . The control shaft 40 is inserted so as to pass through the two bearing portions 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 first arm member 24 can freely rotate around the control shaft 40, the non-oscillating portion 36 is integrated with the control shaft 40, and the oscillating roller portion 38 is non-oscillating portion 36. A mechanism capable of swinging with respect to is realized.

  When the first arm member 24 and the second arm member 26 are assembled as described above, the relative angle between the first arm member 24 and the control shaft 40, that is, the first arm member 24 and the non-oscillating portion 36. In the range where the relative angle satisfies the predetermined condition, the slide roller 50 of the swing roller unit 38 can contact the roller contact surface 28 of the first arm member 24. Then, when the first arm 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 move. 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. 3 and FIG.

  FIG. 1 shows a state in which the first arm member 24, the second arm member 26, and the control shaft 40 are assembled in the above-described procedure. In this state, the positions of the first arm member 24 and the second 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 first arm 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. Is 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 first arm member 24 while rolling on the roller contact surface 28. As a result, the first arm member 24 rotates around the control shaft 40, the rocker arm 22 pushes down the rocker arm 16, and the valve body 12 is given 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 the first embodiment 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. 3 and 4, the lost motion spring 56 urges the rear end portion of the roller contact surface 28 with its upper end fixed to a 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. 3 or FIG.

  FIG. 3 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. 3A shows a state in which the valve body 12 is closed during the small lift operation, and FIG. 3B shows that the valve body 12 is opened during the small lift operation. The state of speaking is shown respectively.

In FIG. 3A, 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. 3A, 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 in which the contact between the cam contact roller 48 and the cam 54 is maintained, as the rotation shaft 46 rotates counterclockwise in FIG. 3, 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. 3A, 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. 3A, 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. 3A, 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. 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. 3B, the variable valve mechanism 10 has a slight contact point 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. 4 shows a state in which the variable valve mechanism 10 is operating 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. 4A shows a state in which the valve body 12 is closed in the process of the large lift operation, and FIG. 4B shows that 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. 4A, 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, also in the case of a large lift operation, the valve body 12 is maintained in a closed state.

When the cam 54 from the state shown in FIG. 4 (A) is rotated, as shown in FIG. 4 (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. 4B, the variable valve mechanism 10 has a sufficient contact point between the rocker roller 20 and the swing arm 22 when such a 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.

  Next, with reference to FIG. 5, the characteristic part of the variable valve mechanism 10 of this embodiment is demonstrated. FIG. 5 is a schematic view showing the structure of the swing roller portion 38 of the variable valve mechanism 10. 5A is a view of the oscillating roller portion 38 as viewed from the axial direction of the slide roller 50, and FIG. 5B shows the roller arm 44 and the slide roller 50 as shown in FIG. It is sectional drawing cut | disconnected by the B line.

  The variable valve mechanism 10 of the present embodiment is characterized by the structure of the roller arm 44 and the slide roller 50 of the swing roller unit 38. That is, as shown in FIG. 5A, a part of the roller contact surface 28 side of the slide roller bearing hole 44b of the roller arm 44 is open. As shown in FIG. 5B, the slide roller 50 has a roller shaft 50a detachably inserted therein. The roller shaft 50a is formed so that the diameter of the portion inserted into the slide roller 50 is larger than the diameter of the portion inserted into the slide roller bearing hole 44b. For this reason, when the slide roller 50 rolls on the roller contact surface 28, it is possible to prevent the roller shaft 50a from moving out in the axial direction without the need to add a stopper member such as a snap ring. Can do.

As described above, the variable valve mechanism 10 of the present embodiment changes the reference arm rotation angle θ _A0 by changing the control shaft rotation angle θ _C, and as a result, the working angle and lift applied to the valve body 12. The amount can be varied. Hereinafter, the variable valve mechanism 10, operating angle and lift amount of the predetermined variable range of the use range of the control shaft rotation angle theta _C be configured to control the "control shaft rotation angle theta _C usually given to the valve body 12 It is referred to as “usage range”.

When the control shaft rotation angle θ _C is within the normal use range, the slide roller 50 always has the inner periphery of the slide roller bearing hole 44b of the roller arm 44 by the roller contact surface 28 by the urging force of the lost motion spring 56. It is kept pressed against the surface (see FIG. 3 or FIG. 4). Therefore, when the control shaft rotation angle θ _C is within the normal use range, the slide roller 50 can roll on the roller contact surface 28 without being detached from the roller arm 44.

In the variable valve mechanism 10 of the present embodiment, the reference arm rotation angle θ _A0 representing the reference position of the swing arm 22 is determined by the position of the slide roller 50 as described above. Therefore, when the diameter of the slide roller 50 is changed, the operating angle and the lift amount of the valve body 12 change. For this reason, when the slide roller 50 is configured to be easily replaceable, it is possible to easily finely adjust the operating angle and lift amount of the valve body 12 when the variable valve mechanism 10 is assembled or maintained. It becomes. Therefore, the variable valve mechanism 10 of the present embodiment is configured such that the state in which the slide roller 50 and the roller contact surface 28 do not contact each other is established on the actual machine. According to such a configuration, by setting the variable valve mechanism 10 to that state, the slide roller 50 can be removed from the roller arm 44 and easily replaced.

FIG. 6 is a diagram for explaining a method for replacing the slide roller 50. As shown in FIG. 6, the variable valve mechanism 10 of this embodiment, to a region beyond the normal use range of the control shaft rotation angle theta _C, anticlockwise in direction (FIG. 6 in which the control shaft rotation angle theta _C increases ), The cam contact roller 48 is not restricted by the cam 54, and the swing roller portion 38 can rotate around the rotation shaft 46 of the second arm member 26. . Then, by rotating the swing roller portion 38 counterclockwise, the slide roller 50 and the roller contact surface 28 are not in contact with each other. According to such a procedure, the slide roller 50 can be detached from the roller arm 44, and the slide roller 50 can be replaced.

As described above, according to the variable valve mechanism 10 of the present embodiment, when the control shaft rotation angle θ _C is within the normal use range, the slide roller 50 is in contact with the roller without being disengaged from the roller arm 44. it is possible to roll on the surface 28, by rotating the control shaft 40 to the area beyond the normal use range of the control shaft rotation angle theta _C, it is possible to easily replace the slide roller 50. For this reason, according to the mechanism of the present embodiment, it is possible to easily adjust the operating angle and lift amount of the valve body 12 during assembly or maintenance.

  In the variable valve mechanism 10, the valve opening characteristics of the valve body 12 may vary between cylinders due to initial tolerances and assembly tolerances of individual members. According to the variable valve mechanism 10 of the present embodiment, in such a case, the operating angle and lift of the valve body 12 between the cylinders can be changed by replacing the slide roller 50 by the above method and appropriately changing the diameter thereof. The amount variation can be easily adjusted. Further, the variable valve mechanism 10 of the present embodiment described above is a mechanism for driving two intake valves or two exhaust valves disposed in a single cylinder, but is disposed in a single cylinder. Further, a variable valve mechanism similar to the variable valve mechanism 10 may be provided for each of the plurality of valve bodies. In this case, by appropriately changing the diameter of the slide roller corresponding to each valve body, it is possible to adjust the variation in the operating angle and the lift amount between the valve bodies.

By the way, in Embodiment 1 mentioned above, although the example which can replace | exchange the slide roller 50 was shown easily, this invention will be in the slide roller 50 if it is a roller which affects the working angle and / or lift amount of a valve body. It can be applied without limitation. In the variable valve mechanism 10 of the present embodiment, the working angle and lift amount of the valve body 12 can be finely adjusted by changing the diameter of the cam contact roller 48. Therefore, the cam contact roller may be easily replaceable by the same method as in the first embodiment. That is, as in the modification shown in FIG. 7, the cam contact roller bearing hole 62a provided in the roller arm 60 is replaced with the cam 64 (in this modification, the “contact member” in the first invention). ) Side part may be opened. According to such a configuration, the cam contact roller 62 and the cam are not in contact with each other by rotating the control shaft 40 until the control shaft rotation angle θ _C exceeds the normal use range. 62 can be easily replaced.

In the first embodiment described above, the rotation position (control shaft rotation angle θ _C ) of the control shaft 40 is adjusted. However, the operating angle and / or the 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 first arm member 24 and the second arm member 26 are the second arm excluding the slide roller 50 and the cam contact roller in the “transmission mechanism” in the first invention. The member 26 and the roller contact surface 28 correspond to the “variable mechanism” in the first invention, and the roller contact surface 28 corresponds to the “contact member” in the first invention.

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 1st arm member and the 2nd arm member which are the components of the variable valve mechanism shown in FIG. 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 the schematic which shows the structure of the rocking | swiveling roller part which is the characterizing part of the variable valve mechanism of Embodiment 1 of this invention. It is a figure for demonstrating the replacement | exchange method of the slide roller shown in FIG. It is a figure which shows the modification which can replace | exchange the roller of this invention easily.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Variable valve mechanism 12 Valve body 16 Rocker arm 20 Rocker roller 22 Swing arm 24 First arm member 26 Second arm member 28 Roller contact surface 32 Concentric part 34 Press part 36 Non-swing part 38 Swing roller part 40 Control shaft 44, 60 Roller arm 44a Cam contact roller bearing hole 44b Slide roller bearing hole 46 Rotating shaft 48, 62 Cam contact roller 50 Slide roller 50a Roller shaft 54, 64 Cam 62a Cam contact roller bearing hole θ _C Control shaft Rotation angle θ _A Arm rotation angle

Claims (3)

A control shaft whose position is adjusted to change the working angle and / or lift amount of the valve body within a predetermined variable range, and a cam and the valve body are interposed between the cam and the valve body to transmit the cam pressing force to the valve body. A variable valve mechanism comprising a transmission mechanism for
The transmission mechanism has a function of changing the operating angle and / or the lift amount according to the position of the control shaft, and a roller for transmitting the pressing force of the cam to the valve body in a state of contact with the contact member. A roller bearing hole that rotatably supports the roller and is opened on a side where the roller contacts the contact member;
When the position of the control shaft is within the normal use range, the roller and the contact member abut, and when the control shaft is displaced to a region exceeding the normal use range, the roller and the A variable valve mechanism, wherein the contact member can be in a non-contact state. The roller includes a roller shaft detachably inserted into the roller,
The roller bearing holes are arranged in a pair at both ends of the roller shaft,
2. The variable valve mechanism according to claim 1, wherein a diameter of a portion of the roller shaft interposed between the pair of roller bearing holes is larger than a diameter of a portion inserted into the pair of roller bearing holes. When the control shaft is displaced beyond the normal use range to a position where the cam and the transmission mechanism do not come into contact with each other when mounted on the internal combustion engine, the roller and the contact member do not come into contact with each other. The variable valve mechanism according to claim 1, wherein the variable valve mechanism is configured to be in a state.

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