JP2007064181A - Variable valve gear - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To adjust dispersion of valve open characteristics among cylinders and valves with a simple and sure method in a variable valve gear. <P>SOLUTION: A control shaft 22 driven and rotated by an actuator is provided. A control arm 24 supported by the control shaft 2 and changing rotation angle thereof according to rotation position of the control shaft 22 is provided. An adjustment mechanism 50 for adjusting attachment angle of the control arm 24 to the control shaft 22 is provided. Adjustment mechanism 50 is provided with a fixing pin 52 press-fitted in the control shaft 22 having a part thereof project out of the control shaft 22, a universal link 54 rotatably engaged with the fixing pin 52, and a fixing bolt 56. A projection part 24a of the control arm 24 and the universal link 54 are fastened by the fixing bolt 56 via an adjustment shim 58. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a variable valve operating apparatus, and more particularly to a variable valve operating apparatus for an internal combustion engine capable of mechanically changing the valve opening characteristics of the valve.

  Conventionally, for example, Patent Document 1 discloses a variable valve mechanism that can mechanically change a valve operating angle and a lift amount. In this variable valve mechanism, a plurality of members are interposed between the cam and the valve in order to change the valve operating angle and the lift amount. An adjustment shim is disposed between these members, more specifically, between the swing cam contact roller and the driven portion. According to such a configuration, variation in the valve operating angle and the lift amount among the cylinders can be adjusted by changing the thickness of the adjustment shim.

Japanese Patent Laid-Open No. 2005-9446

  In the configuration of the conventional variable valve mechanism, the camshaft needs to be attached and detached in order to change the adjustment shim to a different thickness. On the other hand, if the valve operating angle and the lift amount can be adjusted without having to detach the camshaft, the adjustment workability can be improved.

  The present invention has been made to solve the above-described problems, and provides a variable valve operating device that can adjust the variation in valve opening characteristics between cylinders or between valves by a simple and reliable method. The purpose is to do.

In order to achieve the above object, a first invention includes a control shaft that is rotationally driven by an actuator, and a control arm that is supported by the control shaft and whose rotation angle is changed according to the rotational position of the control shaft. , A variable valve operating device in which a valve opening characteristic is changed according to a rotation angle of the control arm,
An adjustment mechanism for adjusting the mounting angle of the control arm with respect to the control shaft;
The adjustment mechanism is
A fixing member fixed to the control shaft such that a part protrudes from the control shaft;
A projecting portion provided to project from the control arm at a position facing the fixing member;
A positioning member interposed between the fixing member and the protruding portion and defining a relative position between the fixing member and the protruding portion is provided.

  According to a second aspect, in the first aspect, the adjustment mechanism is configured so that the control shaft and the control arm are arranged in the same direction as the axis of the control shaft around a position eccentric from the center of the control shaft. It further comprises a rotation mechanism that allows the positioning member to rotate with respect to either one.

In a third aspect based on the second aspect, the positioning member is a fixing bolt,
The rotation mechanism rotates a first engagement member fixed to the fixing member, a second engagement member meshed with the fixing bolt, and the first engagement member and the second engagement member. And a support pin to be freely engaged.

  According to a fourth aspect of the present invention, in the third aspect of the present invention, the first engagement member is provided with a protrusion only at a portion outside the outer diameter of the support pin at the end thereof. To do.

  According to a fifth aspect of the invention, in the third or fourth aspect of the invention, the fixing member is fixed in a state in which an axis thereof is offset with respect to the axial center of the control shaft to a side far from the projecting portion. It is characterized by.

  According to a sixth aspect, in any one of the third to fifth aspects, the control arm includes a guide portion formed so as to cover both ends of the support pin.

Further, in a seventh aspect based on the second aspect, the positioning member is a screw having a spherical portion formed in a spherical shape at one end thereof,
The fixing member includes a guide wall that engages with the spherical portion, and includes a guide member that houses the spherical portion,
The rotating mechanism is characterized in that the spherical portion and the guide wall are included.

In addition, an eighth invention according to any one of the first to seventh inventions, wherein the adjustment mechanism interposes an adjustment shim between the fixing member and the protruding portion, and changes a thickness of the adjustment shim. By doing so, the mounting angle of the control arm with respect to the control shaft can be adjusted,
The positioning member includes a small-diameter portion and a large-diameter portion having a diameter larger than the small-diameter portion,
The adjustment shim includes an engagement hole having a diameter equal to the diameter of the large diameter portion, and a slit having a width equal to the diameter of the small diameter portion,
When adjusting the mounting angle of the control arm, the positioning member and the adjustment shim are combined by the small diameter portion and the slit, and when the adjustment of the mounting angle is completed, the large diameter portion and the engagement hole are engaged. It is comprised so that it may be in a state to match.

  According to the first invention, the mounting angle of the control arm with respect to the control shaft is adjusted by adjusting the relative position between the fixed member fixed to the control shaft and the protrusion provided on the control arm by the positioning member. Can do. Therefore, according to the present invention, it is possible to adjust the variation in the valve opening characteristics between the cylinders or between the valves in a simple and reliable manner without having to remove the components interposed between the cam and the valve. it can.

  According to the second invention, by enabling the positioning member to rotate with respect to either the control shaft or the control arm, when adjusting the mounting angle of the control arm with respect to the control shaft, The angle of the positioning member with respect to the other of the two can be set to an ideal angle for realizing reliable fastening that is difficult to loosen the control shaft and the control arm.

  According to the third aspect of the invention, when the mounting angle of the control arm with respect to the control shaft is adjusted, the fixing bolt that is a positioning member is rotatable around the support pin, so that the fixing bolt is fixed to the protrusion (control arm). Can always be assembled at right angles. For this reason, according to the present invention, the fastening between the fixing bolt and the protruding portion can always be maintained in a surface contact state regardless of the mounting angle of the control arm with respect to the control shaft, and the sufficient axial force of the fixing bolt can be maintained. Thus, the control shaft and the control arm can be securely fixed.

  According to the fourth aspect, when the first engagement member is press-fitted into the control shaft together with the fixing member, the engagement portion of the support pin in the first engagement member can be prevented from being deformed.

  According to the fifth aspect of the present invention, it is possible to increase the attachment angle of the positioning member with respect to the fixed member as compared with the case where the fixed member is fixed so that the axis of the fixed member passes through the center of the control shaft. For this reason, according to the present invention, the cross-sectional area of the first engaging member can be enlarged, whereby the rigidity of the fixing member and the first engaging member can be improved, and the fixing member and the first engaging member can be improved. The stress acting on the engaging member can be reduced.

  According to the sixth aspect, since the axial position of the support pin is regulated by the guide portion, it is not necessary to fix the support pin by caulking between the first engagement member and the second engagement member. . Therefore, according to the present invention, the first engagement member and the second engagement member are not deformed in order to hold the support pin, and an inexpensive configuration can be obtained. It is possible to prevent uneven wear.

  According to the seventh aspect, when adjusting the mounting angle of the control arm with respect to the control shaft, the screw as the positioning member is rotatable about the guide wall as a fulcrum, so that the screw is always assembled at a right angle to the protrusion. be able to. For this reason, according to the present invention, the fastening between the screw and the protruding portion can always be maintained in a surface contact state regardless of the mounting angle of the control arm with respect to the control shaft, and the control is performed with sufficient axial force of the screw. The shaft and the control arm can be securely fixed.

  According to the eighth aspect, the adjustment shim can be easily replaced at the time of adjustment while ensuring that the adjustment shim does not come off after completion of the adjustment.

Embodiment 1 FIG.
[Configuration of variable valve gear]
Hereinafter, with reference to FIG. 1 thru | or FIG. 3, the structure of the variable valve apparatus 10 of Embodiment 1 of this invention is demonstrated.
FIG. 1 is a side view showing a configuration of a variable valve operating apparatus 10 according to a first embodiment of the present invention. More specifically, FIG. 1 is a cross-sectional view of the variable valve gear 10 cut at a position where a drive cam 14 described later is provided. A variable valve operating apparatus 10 shown in FIG. 1 is an apparatus 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 device that drives two intake valves or two exhaust valves disposed in each cylinder.

  This variable valve operating apparatus 10 has a rocker arm type mechanical valve operating mechanism, and the rotational motion of the cam shaft 12 is converted into the rocking motion of the rocker arm 16 by the drive cam 14 provided on the cam shaft 12. This is converted into a lift movement in the vertical direction of the valve 18 supported by the arm 16. In the variable valve operating apparatus 10, the rocker arm 16 is not directly driven by the drive cam 14, but the variable mechanism 20 is interposed between the drive cam 14 and the rocker arm 16. The variable mechanism 20 is a mechanism that can continuously change the interlocking state between the rotational motion of the drive cam 14 and the rocking motion of the rocker arm 16. The variable valve operating apparatus 10 can continuously change the lift amount and operating angle of the valve 18 by changing the swing amount and swing timing of the rocker arm 16 by variably controlling the variable mechanism 20. ing.

  As shown in FIG. 1, in the variable valve gear 10, the rocker arm 16 is supported by a valve 18. The variable mechanism 20 is interposed between the drive cam 14 and the rocker arm 16 so as to continuously change the interlocking state between the rotational motion of the drive cam 14 and the rocking motion of the rocker arm 16.

  As will be described below, the variable mechanism 20 includes a control shaft 22, a control arm 24, a link arm 26, a swing cam arm 28, a first roller 30, and a second roller 32 as main components. The control shaft 22 is disposed in parallel with the cam shaft 12. The rotation angle of the control shaft 22 can be controlled to an arbitrary angle by an actuator (not shown) such as a motor.

  The control arm 24 is integrally fixed to the control shaft 22 via an adjusting mechanism 50 (not shown in FIG. 1) which will be described later with reference to FIG. The control arm 24 protrudes in the radial direction of the control shaft 22, and an arc-shaped link arm 26 is attached to the protruding portion. The rear end portion of the link arm 26 is rotatably connected to the control arm 24 by a pin 34. The position of the pin 34 is eccentric from the center of the control shaft 22, and this pin 34 becomes a swing fulcrum of the link arm 26.

  The swing cam arm 28 is supported by the control shaft 22 so as to be swingable, and the tip thereof is disposed toward the upstream side in the rotational direction of the drive cam 14. A slide surface 36 that contacts the second roller 32 is formed on the side of the swing cam arm 28 facing the drive cam 14. The slide surface 36 is formed in a curved surface such that the distance from the drive cam 14 gradually decreases as the second roller 32 moves from the distal end side of the swing cam arm 28 toward the axial center side of the control shaft 22. . A swing cam surface 38 is formed on the opposite side of the slide surface 36. The swing cam surface 38 is formed such that the distance from the swing center of the swing cam arm 28 is constant, and the position away from the non-work surface 38a is closer to the center of the control shaft 22. The working surface 38b is formed so as to be far away.

  A first roller 30 and a second roller 32 are disposed between the slide surface 36 of the swing cam arm 28 and the peripheral surface of the drive cam 14. More specifically, the first roller 30 is disposed so as to contact the peripheral surface of the drive cam 14, and the second roller 32 is disposed so as to contact the slide surface 36 of the swing cam arm 28. Both the first roller 30 and the second roller 32 are rotatably supported by a connecting shaft 40 fixed to the tip end portion of the link arm 26 described above. Since the link arm 26 can swing about the pin 34 as a fulcrum, these rollers 30 and 32 can also swing along the slide surface 36 and the peripheral surface of the drive cam 14 while maintaining a certain distance from the pin 34.

  The swing cam arm 28 is provided with a lost motion spring (not shown). The lost motion spring is a compression spring, and the urging force from the lost motion spring acts as a force by which the slide surface 36 urges the second roller 32 and further presses the first roller 30 against the drive cam 14. As a result, the first roller 30 and the second roller 32 are positioned in a state of being sandwiched from both sides by the slide surface 36 and the peripheral surface of the drive cam 14. The lost motion spring is not limited to the compression spring described above, and may be a torsion spring, for example.

  The aforementioned rocker arm 16 is disposed below the swing cam arm 28. A rocker roller 42 is disposed on the rocker arm 16 so as to face the swing cam surface 38. The rocker roller 42 is rotatably attached to an intermediate portion of the rocker arm 16. One end of the rocker arm 16 is supported by a valve shaft 44 of the valve 18, and the other end of the rocker arm 16 is rotatably supported by a hydraulic lash adjuster 46. During the lift operation, the valve shaft 44 is urged by a valve spring (not shown) in the closing direction, that is, the direction in which the rocker arm 16 is pushed up. Further, the rocker roller 42 is coupled with the urging force and the hydraulic lash adjuster. 46 is pressed against the swing cam surface 38 of the swing cam arm 28.

  According to the configuration of the variable mechanism 20 described above, the pressing force of the driving cam 14 is transmitted to the slide surface 36 via the first roller 30 and the second roller 32 as the driving cam 14 rotates. As a result, when the contact between the swing cam surface 38 and the rocker roller 42 extends from the non-operation surface 38a to the operation surface 38b, the rocker arm 16 is pushed down and the valve 18 is opened.

  Further, according to the configuration of the variable mechanism 20, when the control shaft 22 is rotated, the rotation angle of the control arm 24 is changed, and the position of the second roller 32 on the slide surface 36 is changed. The swing range of the cam arm 28 changes. More specifically, when the control shaft 22 is rotated counterclockwise in FIG. 1, the position of the second roller 32 on the slide surface 36 moves to the tip side of the swing cam arm 28. Then, after the oscillating cam arm 28 starts the oscillating operation by transmitting the pressing force of the drive cam 14, the rotation angle of the oscillating cam arm 28 that is actually required until the rocker arm 16 starts to be pressed is determined by the control shaft. 22 becomes larger as it rotates counterclockwise in FIG. That is, according to the variable mechanism 20, the operating angle and lift amount of the valve 18 can be reduced by rotating the control shaft 22 counterclockwise in FIG. By rotating in the direction, the working angle and lift amount of the valve 18 can be increased.

[Characteristics of this embodiment]
Next, with reference to FIG. 2 thru | or FIG. 6, the characteristic structure of the variable valve apparatus 10 of this embodiment is demonstrated.
FIG. 2 is a perspective view of the variable valve apparatus 10 shown in FIG. In the variable valve operating device, due to the processing accuracy and assembly accuracy of each component, the valve operating angle and the lift amount vary among the cylinders in a state where these components are assembled. As shown in FIG. 2, the variable valve operating apparatus 10 according to the present embodiment includes an adjustment mechanism 50 for adjusting such variation in operating angle and lift amount between cylinders. More specifically, the adjustment mechanism 50 is a mechanism for adjusting the mounting angle of the control arm 24 with respect to the control shaft 22, and includes a fixing pin 52, a universal link 54, a fixing bolt 56, and an adjustment shim 58. .

  FIG. 3 is a view for explaining the relationship between the fixing pin 52 and the universal link 54. More specifically, FIG. 3A is a view seen from the axial direction of the fixing pin 52, and FIG. 3B is a view seen from the axial direction of the support pin 60. As shown in FIG. 3B, the fixing pin 52 includes a cylindrical portion 52a and a flat portion 52b. Further, the fixing pin 52 is provided with a protrusion 52d formed at the end on the flat portion 52b side so that the tip is a flat surface with a constant distance from the center of the through hole 52c. The protrusion 52d is provided only in the portion outside the through hole 52c portion. By providing such a protrusion 52d on the fixing pin 52, it is possible to prevent the through hole 52c of the fixing pin 52 from being deformed when the fixing pin 52 is press-fitted into the control shaft 22.

  The universal link 54 includes a ring portion 54a formed in a forked shape so that the flat portion 52b of the fixing pin 52 is accommodated therein, and a cylindrical portion 54c in which a screw hole 54b into which the fixing bolt 56 is engaged is formed. It has. As shown in FIG. 3A, the fixed pin 52 and the free link 54 are rotatable about the support pin 60 by inserting the support pin 60 into the through hole 52c and the ring portion 54a of the flat portion 52b. Both are combined so that The ring portion 54a of the universal link 54 and the support pin 60 are fixed by caulking.

  FIG. 4 is a view for explaining the detailed structure of the adjusting mechanism 50 shown in FIG. More specifically, FIG. 4A shows a cross-sectional view of the adjusting mechanism 50 viewed from the axial direction of the control shaft 22, and FIG. 4B shows the adjusting mechanism 50 viewed from the axial direction of the fixing bolt 56. The figure is shown. As shown in FIG. 4A, the control shaft 22 is provided with a through hole 62 having a center line that passes through the center of the control shaft 22 and is orthogonal to the axis of the control shaft 22. The cylindrical portion 52 a of the fixing pin 52 is press-fitted into the through hole 62. The control arm 24 is provided with a protruding portion 24 a at a position facing the fixed pin 52 so as to protrude in the radial direction of the control shaft 22. An elongated hole 24b formed so that the Y direction in FIG. 5A is the longitudinal direction is formed in the protruding portion 24a.

  The fixing bolt 56 includes a screw portion 56a having a predetermined length, a small-diameter portion 56b having a predetermined diameter d1, and a large-diameter portion 56c having a diameter d2 larger than the diameter d1, in order from the bolt tip. The adjustment shim 58 is incorporated between the protruding portion 24a and the universal link 54 in a state where the fixing bolt 56 is inserted into the elongated hole 24b of the protruding portion 24a. The adjustment shim 58 is formed in a C-shaped portion to be inserted into the fixing bolt 56. More specifically, the adjustment shim 58 is provided with an engagement hole 58a having the same diameter D as the large diameter portion 56c of the fixing bolt 56, and has a width L equal to the diameter d1 of the small diameter portion 56b. A slit 58b is provided.

  FIG. 5A shows a state where the adjustment shim 58 has been assembled. In order to obtain the state shown in FIG. 5A, first, the fixing bolt 56 is fastened to the universal link 54 in a state where the fixing bolt 56 is inserted into the elongated hole 24b of the protruding portion 24a. Next, the adjustment shim 58 is inserted into the small diameter portion 56 b of the fixing bolt 56. Next, tighten the fixing bolt 56 until there is no gap between the universal link 54 and the adjusting shim 58, between the adjusting shim 58 and the protruding portion 24a, and between the protruding portion 24a and the seating surface of the fixing bolt 56. Include. According to such a configuration, when the fixing bolt 56 is fully tightened, the engagement hole 58a of the adjustment shim 58 and the large-diameter portion 56c of the fixing bolt 56 are engaged with each other. Can be reliably prevented from falling out.

  FIG. 5B shows a state in which a thin adjustment shim 64 thinner than the adjustment shim 58 is incorporated. To obtain the state shown in FIG. 5B, first, it is necessary to remove the thick adjustment shim 58 in the adjustment mechanism 50 in the state shown in FIG. Therefore, the fixing bolt 56 is loosened and the fixing bolt 56 is moved in the X direction so that the small diameter portion 56b comes to the position of the thick adjustment shim 58. In this state, the thick adjustment shim 58 can be extracted from the fixing bolt 56. Next, the adjustment shim is replaced from the thick adjustment shim 58 to the thin adjustment shim 64, and the thin adjustment shim 64 is attached by tightening the fixing bolt 56 by the method described above.

  In FIG. 5, in the state where the thick adjustment shim 58 is incorporated, the angle formed by the vertical line passing through the center of the control axis and the protrusion 24a of the control arm 24 is θ1, and in the state where the thin adjustment shim 64 is incorporated, An angle corresponding to the angle θ1 is defined as θ1 ′. In the state where the thin adjustment shim 64 is incorporated, as shown in FIG. 5B, the distance between the flat portion 52b of the fixing pin 52 and the protruding portion 24a is shorter than that in the state shown in FIG. Therefore, θ1 ′ <θ1. That is, the control arm 24 rotates counterclockwise in FIG. 5 by replacing the adjustment shim with a thin one. As a result, the position of the second roller 32 on the slide surface 36 moves to the tip side of the swing cam arm 28, and the operating angle and lift amount of the valve 18 can be reduced.

  As described above, according to the adjusting mechanism 50 of the present embodiment, the camshaft 12 can be attached and detached only by loosening the fixing bolt 56, replacing it with an adjusting shim having a different thickness, and then fastening the fixing bolt 56 again. Thus, it is possible to easily and reliably adjust the operating angle of the valve 18 and the variation between cylinders in the lift amount without the need for such a complicated operation.

  As shown in FIG. 5, when the thick adjustment shim 58 is replaced with the thin adjustment shim 64, the free link 54 rotates around the support pin 60, and the axis of the fixing pin 52 and the axis of the fixing bolt 56 form. The angle increases from θ2 to θ2 ′. Since the elongated portion 24b is provided in the protruding portion 24a of the present embodiment, the fixing bolt 56 moves in the Y ′ direction when such an angle change occurs. Therefore, according to the adjustment mechanism 50 of the present embodiment, even when the adjustment shim is changed to one having a different thickness, between the adjustable link 54 and the adjustment shim, between the adjustment shim and the protruding portion 24a, and A surface contact state can be maintained between the protrusion 24a and the seating surface of the fixing bolt 56. Since the driving force from the motor acts on the control arm 24 when the control shaft 22 is rotationally driven, the control shaft 22 and the control arm 24 need to be fastened so as not to loosen. According to the above configuration, it is possible to always fasten the fixing bolt 56 with sufficient axial force regardless of the thickness of the adjustment shim, and the control shaft 22 and the control arm 24 can be securely fastened.

  In the first embodiment described above, the fixing pin 52 corresponds to the “fixing member” in the first invention, and the fixing bolt 56 corresponds to the “positioning member” in the first invention. Further, the flat portion 52b of the fixing pin 52, the universal link 54 and the support pin 60 correspond to the “rotating mechanism” in the second aspect of the invention. Further, the flat portion 52b of the fixing pin 52 corresponds to the “first engagement member” in the third invention, and the universal link 54 corresponds to the “second engagement member” in the third invention.

Embodiment 2. FIG.
Next, a second embodiment of the present invention will be described with reference to FIG.
FIG. 6 is a diagram for explaining the configuration of the adjustment mechanism 70 according to the second embodiment of the present invention. More specifically, FIG. 6 (A) is a view seen from the axial direction of the fixed pin, and FIG. 6 (B) is a side view seen from the axial direction of the control shaft.

  The adjustment mechanism 70 of the present embodiment is the same as the adjustment mechanism 50 of the first embodiment described above except that the fixing position of the fixing pin 74 to the control shaft 72 and the method of supporting the support pin 76 are different. That is, in the adjustment mechanism 70, as shown in FIG. 6, the fixing pin 74 has a through hole 80 formed at a position offset by a predetermined amount on the side far from the protruding portion 78 a of the control arm 78 with respect to the axis of the control shaft 72. It is press-fitted into. Further, the fixing pin 74 of this embodiment is configured such that the area of the flat portion 74b is larger than that of the flat portion 52b of the fixing pin 52 of the first embodiment. Further, the cylindrical portion 74a of the fixing pin 74 is formed with an R groove portion 74c on the circumference thereof.

  In the present embodiment, as shown in FIG. 6A, a guide portion 78c is formed so as to sandwich and cover both ends of the support pin 76 from the protruding portion 78a of the control arm 78. In other words, the guide portion 78c of the control arm 78 is formed so as to overlap the support pin 76 when viewed from the direction shown in FIG. Further, unlike the first embodiment, the support pin 76 is not fixed to the universal link 82 by caulking, and is configured to be rotatable with respect to the universal link 82.

  According to the configuration shown in FIG. 6, the fixing pin 74 is arranged offset from the center of the control shaft 72, so that the axis of the fixing pin 74 and the axis of the fixing bolt 56 can be obtained in the state where each component is assembled. Can be made larger than the configuration of the first embodiment described above. As a result, like the fixing pin 74 described above, it is possible to secure a large area of the flat portion 74b, improve the rigidity of the fixing pin 74, and reduce the stress acting on the fixing pin 74. Can do.

  Further, according to the above configuration, since the caulking is not used to hold the support pin 76, the free link 82 is not deformed at the time of assembly, and an inexpensive configuration can be achieved. And since the support pin 76 becomes rotatable, it can prevent that the support pin 76 wears unevenly. Furthermore, according to the above configuration, the fixed pin 74 is arranged offset from the axis center of the control shaft 72, so the fixed pin 74 does not block the oil supply hole inside the control shaft 72. Then, by changing the groove depth of the R groove portion 74c of the fixed pin 74, it becomes possible to adjust the amount of oil supplied to the pin 34 of the control arm 78.

Embodiment 3 FIG.
Next, Embodiment 3 of the present invention will be described with reference to FIGS.
FIG. 7 is a perspective view for explaining the configuration of the adjusting mechanism 90 according to the third embodiment of the present invention. The adjustment mechanism 90 of this embodiment includes a fixing pin 92, a screw 94, a guide member 96, a lock nut 98, and an adjustment shim 100 as main components.

  FIG. 8 is a view for explaining the structure of the components of the adjusting mechanism 90 shown in FIG. As shown in FIG. 8A, the control shaft 102 is provided with a through hole 104 having a center line orthogonal to the axis of the control shaft 102. A fixing pin 92 is press-fitted into the through hole 104. The fixing pin 92 has a second cylindrical portion 92b having a diameter one step smaller than the diameter of the cylindrical portion 92a at one end thereof.

  As shown in FIG. 8B, the screw 94 includes a spherical portion 94a formed in a spherical shape at one end, and a projection 94c is provided at the other tip of the screw 94 where the screw portion 94b is provided. ing. The guide member 96 has a through hole 96a formed on the bottom surface thereof. The second cylindrical portion 92b of the fixing pin 92 is press-fitted into the through hole 96a. Thereby, the fixing pin 92 and the guide member 96 are integrated. On the upper surface of the guide member 96, an oblique hole 96b for assembling the screw 94 is formed. Further, a guide wall 96 c formed in a cylindrical shape is formed on the side surface of the guide member 96. The guide wall 96c is formed with a long hole 96d whose longitudinal direction is the height direction of the guide wall 96c. The long hole 96d is formed so that the dimension in the short direction is smaller than the outer diameter of the spherical portion 94a.

  When assembling the screw 94 to the guide member 96, first, as shown in FIG. 8B, the screw 94 is inserted into the guide member 96 from the oblique hole 96b so that the screw portion 94b protrudes from the long hole 96d. Next, as shown in FIG. 8C, in a state where the spherical surface portion 94a is inserted into the guide wall 96c, the spherical surface portion 94a is further pushed down, and the screw portion 94b is lifted upward, whereby FIG. ).

  FIG. 9 is a diagram illustrating a state in which each component of the adjustment mechanism 90 is assembled. As shown in FIG. 9, a screw hole 106 b is formed in the protruding portion 106 a of the control arm 106. The screw 94 inserted into the guide member 96 is further screwed into the screw hole 106b of the protruding portion 106a with the spacer 108 inserted into the screw portion 94b. An adjustment shim 100 is inserted between the spacer 108 and the protrusion 106a. In the state where the adjustment shim 100 is inserted, the gap between the spherical portion 94a and the guide wall 96c, and further by holding the projection 94c of the screw 94 with a tool such as a spanner and rotating the screw 94, A gap between the guide wall 96c and the protruding portion 106a can be eliminated via the adjustment shim 100. And the relative position of the control shaft 102 and the control arm 106 can be reliably fixed by incorporating the lock nut 98 in the threaded portion 94b in a state in which these gaps are eliminated.

  Further, as shown in FIG. 9, the height of the end portion of the oblique hole 96b of the guide member 96 is higher by the dimension L than the center of the spherical portion 94a in a state where the spherical portion 94a is placed on the fixed pin 92a. Is set to Thereby, increase of the surface pressure which acts on the guide wall 96c can be suppressed. The spacer 108 has a flat contact surface with the adjusting shim 100 and a curved surface with a predetermined radius R on the opposite surface. According to such a spacer 108, the inclination of the screw 94 can be absorbed.

  FIG. 10A shows a state in which the adjustment shim 100 has been assembled. In the state shown in FIG. 10A, the angle formed by the vertical line passing through the center of the control axis and the protrusion 106a of the control arm 106 is θ3, and the angle formed by the perpendicular of the axis of the fixed pin 92 and the axis of the screw 94 is Let θ4. FIG. 10B shows a state in which the thinner thin adjustment shim 110 of the adjustment shim 100 is incorporated. 10B, first, in the adjustment mechanism 90 in the state of FIG. 10A, the lock nut 98 is loosened, and then the screw 94 is rotated with a spanner or the like, thereby increasing the thickness. Remove the adjustment shim 100. Next, after inserting the thin adjustment shim 110, the screw 94 is rotated in the reverse direction until there is no gap between the components. Then, the lock nut 98 is fastened again. It should be noted that the adjustment of the present embodiment is not limited to the above-described configuration, provided that the shaft of the screw 94 is stepped and the shape of the adjustment shim 110 or the like is the same shape as the adjustment shim 58 or the like in the first embodiment. Also in the mechanism 90, the adjustment shim can be more reliably prevented from coming off.

  As shown in FIG. 10B, by replacing the adjustment shim with a thin one, the angle θ3 becomes θ3 ′, and the control arm 106 rotates counterclockwise in FIG. As a result, the position of the second roller 32 on the slide surface 36 moves to the tip side of the swing cam arm 28, and the operating angle and lift amount of the valve 18 can be reduced.

  As shown in FIG. 10, when the thick adjustment shim 100 is replaced with the thin adjustment shim 110, the angle θ4 changes to θ4 ′. In the adjustment mechanism 90 of the present embodiment, the corresponding portion of the screw 94 that engages with the guide member 96 is the spherical portion 94a. Therefore, when such an angle change occurs, the spherical portion 94a rotates within the guide member 96. By doing so, the angle change is absorbed. Therefore, according to the adjustment mechanism 90 of the present embodiment, even when the adjustment shim is changed to one having a different thickness, the spherical portion 94a, the guide wall 96c, the spacer 108, the adjustment shim, the protruding portion 106a, and the lock nut Between each of the 98 seating surfaces, a surface contact state can always be maintained. For this reason, the control shaft 102 and the control arm 106 can always be coupled with a sufficient axial force of the screw 94 regardless of the thickness of the adjustment shim.

  In the adjustment mechanism 90 of the present embodiment, when the thickness of the adjustment shim is changed, the spherical portion 94a of the screw 94 moves in the axial direction of the fixed pin 92. In order to minimize the amount of movement of the spherical portion 94a, the assembly angle of the screw 94 may be set as follows with respect to the axial direction of the fixed pin 92. The setting method will be described with reference to FIG. More specifically, in FIG. 10, the angle θ4 indicates a state in which the axis of the screw 94 is inclined counterclockwise by the angle θ4 with respect to the normal of the axis of the fixing pin 92, and the angle θ4 ′ is A state in which the axis of the screw 94 is inclined by an angle θ4 ′ in the clockwise direction with respect to the perpendicular of the axis of the fixing pin 92 is shown. Here, it is assumed that the thickness of the adjustment shim used for adjusting the operating angle is set in the range from the thick adjustment shim 100 to the thin adjustment shim 110 in FIG. In such a setting, as shown in FIG. 10, the angle formed by the perpendicular of the axis of the fixing pin 92 and the axis of the screw 94 changes between θ4 and θ4 ′. In such a case, if the assembly angle of the screw 94 with respect to the axial direction of the fixing pin 92 is set so that the absolute values of the angle θ4 and the angle θ4 ′ are equal, the movement amount of the spherical portion 94a described above Can be minimized.

  In the third embodiment described above, the adjustment shim 100 or the like is interposed between the protruding portion 106a of the control arm 106 and the guide member 96, but the present invention is not limited to such a configuration. Instead, the configuration described with reference to FIG. FIG. 11 is a diagram for explaining the configuration of the adjustment mechanism 120 in a modification of the third embodiment of the present invention. As shown in FIG. 11 (A), the adjustment mechanism 120 in this modification is a shimless type adjustment mechanism that does not use an adjustment shim. Since the spherical portion 94a of the screw 94 is accommodated in the guide member 96, in this state, the screw 94 is restricted from moving in the axial direction. The position of the other end of the screw 94 with respect to the control arm 106 is fixed by fastening a screw portion 94b of the screw 94 engaged with the protruding portion 106a with a lock nut 98.

  In the configuration shown in FIG. 11, the method of changing the mounting angle of the control arm 116 with respect to the control shaft 102 so that the working angle and the lift amount of the valve 18 are small is the above-mentioned except that there is no replacement work of the adjustment shim. This is the same as in the third embodiment. FIG. 11B shows a state in which such adjustment has been made. According to the above configuration, a slight rattling occurs between the guide member 96 and the spherical surface portion 94a as compared with the case where the adjustment shim is used, but this is simplified without using the adjustment shim. With the configuration, the operating angle of the valve 18 and the variation in the lift amount among the cylinders can be adjusted.

  In the third embodiment described above, the fixing pin 92 and the guide member 96 correspond to the “fixing member” in the first invention, and the screw 94 corresponds to the “positioning member” in the first invention. Yes. Further, the spherical portion 94a and the guide wall 96c of the screw 94 correspond to the “rotating mechanism” in the second invention.

It is a side view which shows the structure of the variable valve apparatus of Embodiment 1 of this invention. It is a perspective view of the variable valve apparatus shown in FIG. FIG. 3 is a diagram for explaining a relationship between a fixed pin and a universal link in the adjustment mechanism shown in FIG. 2. It is a figure for demonstrating the detailed structure of the adjustment mechanism shown in FIG. FIG. 3 is a diagram for explaining a state in which adjustment shims having different thicknesses are incorporated in the adjustment mechanism shown in FIG. 2. It is a figure for demonstrating the structure of the adjustment mechanism of Embodiment 2 of this invention. It is a perspective view for demonstrating the structure of the adjustment mechanism of Embodiment 3 of this invention. It is a figure for demonstrating the structure of the component of the adjustment mechanism shown in FIG. It is a figure which shows the state by which each component of the adjustment mechanism shown in FIG. 7 was assembled | attached. FIG. 8 is a view for explaining a state in which adjustment shims having different thicknesses are incorporated in the adjustment mechanism shown in FIG. 7. It is a figure for demonstrating the structure of the adjustment mechanism in the modification of Embodiment 3 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Variable valve apparatus 20 Variable mechanism 22,72,102 Control shaft 24,78,106 Control arm 24a, 78a, 106a Protruding part 24b Slot 50,70,90,120 Adjustment mechanism 52,74,92 Fixed pin 52a, 74a, 92a Cylindrical portion 52b, 74b Flat portion 52d Protruding portion 54, 82 Free link 56 Fixing bolt 56b Small diameter portion 56c Large diameter portion 58, 100 Thickness adjustment shim 60, 76 Support pin 64, 110 Thin adjustment shim 78c Guide portion 92b Second cylindrical portion 94 Screw 94a Spherical surface portion 96 Guide member 96c Guide wall 96d Slot 98 Lock nut 106b Screw portion

Claims (8)

A control shaft that is rotationally driven by an actuator, and a control arm that is supported by the control shaft and whose rotation angle is changed according to the rotation position of the control shaft, and opens the valve according to the rotation angle of the control arm A variable valve operating device whose characteristics are changed,
An adjustment mechanism for adjusting the mounting angle of the control arm with respect to the control shaft;
The adjustment mechanism is
A fixing member fixed to the control shaft such that a part protrudes from the control shaft;
A projecting portion provided to project from the control arm at a position facing the fixing member;
A variable valve operating apparatus, comprising: a positioning member interposed between the fixing member and the projecting portion and defining a relative position between the fixing member and the projecting portion.   The adjusting mechanism can rotate the positioning member with respect to one of the control shaft and the control arm in the same direction as the axis of the control shaft, with a position eccentric from the center of the control shaft as a center. The variable valve operating apparatus according to claim 1, further comprising a rotation mechanism. The positioning member is a fixing bolt,
The rotation mechanism rotates a first engagement member fixed to the fixing member, a second engagement member meshed with the fixing bolt, and the first engagement member and the second engagement member. The variable valve operating device according to claim 2, further comprising a support pin that is freely engaged.   4. The variable valve operating apparatus according to claim 3, wherein the first engaging member is provided with a protrusion only at a portion outside the outer diameter of the support pin at an end thereof.   5. The variable valve operating apparatus according to claim 3, wherein the fixing member is fixed in a state in which an axis thereof is offset to a side far from the projecting portion with respect to an axis center of the control shaft.   6. The variable valve operating apparatus according to claim 3, wherein the control arm includes a guide portion formed so as to cover both ends of the support pin. The positioning member is a screw having a spherical portion formed in a spherical shape at one end thereof,
The fixing member includes a guide wall that engages with the spherical portion, and includes a guide member that houses the spherical portion,
The variable valve operating apparatus according to claim 2, wherein the rotation mechanism is the spherical portion and the guide wall. The adjustment mechanism can adjust the mounting angle of the control arm with respect to the control shaft by interposing an adjustment shim between the fixing member and the protrusion and changing the thickness of the adjustment shim. And
The positioning member includes a small-diameter portion and a large-diameter portion having a diameter larger than the small-diameter portion,
The adjustment shim includes an engagement hole having a diameter equal to the diameter of the large diameter portion, and a slit having a width equal to the diameter of the small diameter portion,
When adjusting the mounting angle of the control arm, the positioning member and the adjustment shim are combined by the small diameter portion and the slit, and when the adjustment of the mounting angle is completed, the large diameter portion and the engagement hole are engaged. The variable valve operating apparatus according to any one of claims 1 to 7, wherein the variable valve operating apparatus is configured to be in a state of being combined.

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