JP4833102B2 - Variable valve mechanism - Google Patents

Description

  The present invention relates to a variable valve mechanism that changes an opening / closing amount of a valve in accordance with an operating state of an internal combustion engine.

  Some variable valve mechanisms change the open / close amount of the valve by operating a rocker arm interposed between a rotary cam and a valve so as to be swingable. As an example, FIG. Like the variable valve mechanism 80 of the first conventional example shown in FIG. 1A, the first rocker arm 83 and the second rocker arm 84 are arranged on the same shaft 81 so as to be swingable. , 84 are connected to each other so as not to be relatively displaceable from each other, and the open / closed amount of the valve is changed by switching between a connected state in which the connection is released (Patent Document 1) and FIG. Like the variable valve mechanism 90 of the second conventional example shown in FIG. 2B, a rocker arm 92 including an outer arm 93 provided on the outer side and an inner arm 94 provided on the inner side of the outer arm 93 is provided. Therefore, the opening / closing amount of the valve is changed by switching between a connection state in which the outer arm 93 and the inner arm 94 are connected to each other so as not to be relatively displaceable and a connection release state in which the connection is released (Patent Document). 2) etc. are known.

The switching will be described in more detail. In the switching mechanism 86 of the first conventional example, the connecting pin 87 is moved by a hydraulic pin driving mechanism 88 provided outside the first and second rocker arms 83 and 84. In the switching mechanism 96 of the second conventional example, the hydraulic mechanism provided outside the rocker arm 92 by driving between a position straddling between the first rocker arm 83 and the second rocker arm 84 and a position not straddling. The switching is performed by driving the connecting pin 97 between a position straddling between the outer arm 93 and the inner arm 94 and a position not straddling by the pin driving mechanism 98 such as the above.
JP 2006-132378 A US Patent Application Publication No. 2005/132990

  However, the first rocker arm 83 and the second rocker arm 84 are required in the rocker arm of the first conventional example, and the arm composed of the outer arm 93 and the inner arm 94 in the rocker arm 92 of the second conventional example. Therefore, the number of parts increases and the structure of the rocker arm becomes complicated.

  Also, in both conventional switching mechanisms 86 and 96, pin driving mechanisms 88 and 98 for driving the connecting pins 87 and 97 are separately required outside the rocker arm. 96 are complicated.

Therefore, while simplifying the structure of the rocker arm, the purpose to simplify the structure of the switching mechanism.

In order to achieve the above object, the variable valve mechanism of the present invention is a variable valve mechanism that changes the opening / closing amount of the valve by operating a rocker arm that is swingably interposed between the rotary cam and the valve. In the mechanism, the rocker arm includes an arm main body including a swing center portion of the arm and a portion that contacts the valve, and a portion that contacts the rotating cam linearly with respect to the main body. A displacement member that is attached so as to be capable of relative displacement in the pressing direction by a rotating cam, wherein the arm body and the displacement member are coupled to each other so that the relative displacement is impossible, and the relative A switching mechanism that switches between a disconnected state and a disconnected state so that displacement is possible, and changes the opening and closing amount of the valve by the switching, and the switching mechanism releases the connection A pin that spans between the arm body and the displacement member when in the connected state, and a hydraulic chamber provided inside the arm body that hydraulically drives the pin. An oil passage that supplies the hydraulic pressure to the hydraulic chamber, and an input roller that contacts the rotating cam of the displacement member is rotatably supported by the pin . A mounting hole extending in the displacement direction is provided, and the displacement member is mounted in the mounting hole, and a pair of pins extending in the displacement direction of the displacement member and having a width substantially equal to the width of the pin on the inner surface of the mounting hole The groove is recessed, and when the connection is released, both ends of the pin enter the inside of the pair of pin grooves, respectively, thereby preventing the displacement member from rotating .

  The change in the opening / closing amount of the valve here is not particularly limited, but switching is performed between a driving state in which the valve is driven according to the rotation of the rotating cam and a driving stop state in which the driving is completely stopped. Another example is a case of switching between a high lift state in which the valve is opened and closed with a relatively large lift amount and a low lift state in which the valve is opened and closed with a relatively small lift amount according to the rotation of the rotating cam.

  Although the rocker arm is not particularly limited, the rocker arm includes a swing center portion at a base end portion of the arm main body, the displacement member is attached to a middle portion in the length direction of the arm main body, and the valve at the distal end portion of the arm main body. Or a swing center portion at the middle in the longitudinal direction of the arm body, the displacement member is attached to the rear end portion of the arm body, and the valve abuts on the distal end portion of the arm body. An example is given.

Further , the switching mechanism is not particularly limited, but is housed in the arm body when the pin is in the released state and the first pin as the pin, and between the arm body and the displacement member when in the connected state. a second pin extending over, and the hydraulic chamber for driving said first pin and said second pin hydraulically, it is preferably formed and a said oil passage.

  The form of the variable valve mechanism at this time is not particularly limited, but the rocker arm is attached to the tip of a hydraulic lash adjuster, and the oil passage is provided inside the lash adjuster and inside the arm body. An example is provided via the.

  The rocker arm is not particularly limited, but is preferably a two-valve integrated arm that simultaneously drives the two valves. This is because the number of rocker arms can be reduced, whereby the structure of the variable valve mechanism can be simplified.

  Further, the structure for supporting the rocker arm so as to be able to swing is not particularly limited, but the fulcrum pin that pivotally supports the swinging central portion of the arm body is the length direction of the fulcrum pin of the pivotally supported portion. It is preferable that the rocker arm is supported so as to be swingable by being supported by a lash adjuster disposed on a side. With such a structure, it is difficult for the rocker arm to be separated from the lash adjuster, and the rocker arm is difficult to tilt in the width direction. Further, at this time, the lash adjuster is not particularly limited, but one lash adjuster is arranged on each side of the arm body, and the arm body is supported by the pair of lash adjusters from the both sides via the fulcrum pins. It is preferable that This is because such a structure makes it more difficult to disperse and more difficult to tilt.

  Moreover, the shape of the main body portion excluding the input roller of the displacement member is not particularly limited, and examples thereof include a substantially triangular prism shape, a substantially quadrangular prism shape, and a substantially cylindrical shape. However, considering the ease of manufacture of the displacement member and the arm body to which the displacement member is attached, among them, the substantially cylindrical shape is preferable.

According to the present invention, unlike the conventional example 1, there is no need to provide two rocker arms, and unlike the conventional example 2, the rocker arm does not need to have a double arm structure including an outer arm and an inner arm. The structure of the rocker arm can be simplified. Further, it is not necessary to separately provide a pin driving mechanism for driving the connecting pin outside the rocker arm as in the conventional examples 1 and 2, and the structure of the switching mechanism can be simplified. Further, since the displacement member includes the input roller, friction with the rotating cam can be reduced.

  The variable valve mechanism 9 of the present invention changes the opening / closing amount of the valve 7 by operating a rocker arm 20 that is swingably interposed between the rotary cam 10 and the valve 7. The rocker arm 20 includes an arm main body 21 including a swinging central portion of the arm and a portion that contacts the valve 7, and a portion that contacts the rotating cam 10. 10 and a displacement member 26 attached to be capable of relative displacement in the pressing direction. The variable valve mechanism 9 includes a connection state in which the arm main body 21 and the displacement member 26 are connected to each other so that the relative displacement is impossible, and a connection in which the connection is released to enable the relative displacement. A switching mechanism 40 for switching between the released state and the opening / closing amount of the valve 7 is changed by the switching.

  The switching mechanism 40 includes a connection pin 45 provided to be displaceable between a position straddling between the arm body 21 and the displacement member 26 and a position not straddling the arm body 21, and an arm main body that drives the connection pin 45 hydraulically. 21 includes an oil pressure chamber 53 provided inside the oil pressure chamber 21, and an oil passage 54 that supplies oil pressure to the oil pressure chamber 53.

  The variable valve mechanism 9 shown in FIGS. 1 to 4 of this embodiment is a mechanism that intermittently changes the opening / closing amount of the valve in accordance with the operating state of the internal combustion engine. In this embodiment, the variable valve mechanism 9 is provided only for half of the cylinders 5 (not shown), and each variable valve mechanism 9 is provided for each cylinder 5. Two intake valves 7 each provided in two are driven simultaneously. The variable valve mechanism 9 operates by driving a rocker arm 20 that is swingably interposed between the valve 7 and the rotary cam 10, thereby driving the valve 7 according to the rotation of the rotary cam 10, and the driving thereof. Is switched to the drive stop state in which the operation is stopped.

  The rotary cam 10 is formed on a camshaft 10x that is rotationally driven as the internal combustion engine operates, and includes a base circle portion 11 that is a basic portion and a cam nose 12 that protrudes from the base circle portion 11. Has been. The rotary cam 10 is disposed above the rocker arm 20, and a cam surface 10 s that presses the input roller 28 of the rocker arm 20 is formed on the outer peripheral surface of the rotary cam 10.

  The rocker arm 20 is a two-valve integrated arm that drives the two valves 7 at the same time. The rocker arm 20 abuts against the arm body 21 including the rocking center of the rocker arm 20 and a portion that contacts the valve 7, and the rotary cam 10. The contacting portion includes a displacement member 26 that is attached to the arm main body 21 so as to be capable of relative displacement in the pressing direction of the rotary cam 10 linearly with respect to the main body 21. Further, the variable valve mechanism 9 releases the connection so that the arm body 21 and the displacement member 26 are connected to each other so that the relative displacement is impossible, and the relative displacement is possible. The switching mechanism 40 for switching between the connected and released states is provided, and switching is performed between the driving state and the driving stopped state by the switching.

  Specifically, the arm main body 21 is a single bar-shaped member extending in a substantially horizontal direction, and is supported by the base end portion 21a so as to be swingable by the lash adjuster 30 in the width direction ( A through hole-like fulcrum hole 22 extending in a substantially horizontal direction) is provided, and a displacement member 26 is attached to the longitudinal intermediate portion 21c. The upper opening extending in the displacement direction (substantially vertical direction) of the displacement member 26 is provided. A mounting hole 24 having a bottom hole shape is provided, and a curved output surface 23 with which the stem end 7e of the valve 7 abuts is provided at the distal end portion 21b.

  The displacement member 26 includes an input roller 28 that rotatably contacts the rotary cam 10 at the top, and the main body portion 27 excluding the input roller 28 has a substantially cylindrical shape. The displacement member 26 is attached to the arm body 21 by the body portion 27 being inserted into the attachment hole 24 of the arm body 21 from the lower part so as to be capable of relative displacement in the through direction of the hole. A lost motion spring 29 that urges the displacement member 26 upward is attached between the lower end surface of the displacement member 26 and the bottom surface of the attachment hole 24.

  The base end portion 21a of the arm main body 21 serving as the rocking center portion of the rocker arm 20 is supported above the cylinder head 6 as follows. That is, the base end portion 21a is pivotally supported by a fulcrum pin 32, and the fulcrum pin 32 is supported from both sides by a pair of lash adjusters 30 disposed on both sides in the length direction. Specifically, each lash adjuster 30 has an upper ring shape having a through hole 31 at the top, and one lash adjuster 30 is provided in each of the three holes of the pair of through holes 31 and the fulcrum hole 22 of the arm body 21. By inserting the fulcrum pin 32 across the three holes, the base end portion 21a of the arm body 21 is supported above the cylinder head 6 so as to be swingable. Therefore, in this embodiment, the rocker arm 20 is less likely to be separated from the lash adjuster 30 than in the case of using an upper hemispherical lash adjuster in which a general rocker arm is placed on the upper side, and the rocker arm 20 extends in the width direction. It is difficult to tilt.

  The switching mechanism 40 presses the connection pin 45 in one direction with hydraulic pressure, and a connection pin 45 provided so as to be displaceable between a position straddling the arm body 21 and the displacement member 26 and a position not straddling the arm body 21 and the displacement member 26. The hydraulic mechanism 51 includes a spring 48 that presses the connecting pin 45 in the other direction opposite to the one direction. Specifically, the switching mechanism 40 is in a disconnected state by driving the connection pin 45 in one direction with the hydraulic pressure of the hydraulic mechanism 51, and loosening the hydraulic pressure and driving in the other direction with the pressing force of the spring 48, Connected.

  The connecting pin 45 is attached to a pin hole 41 provided in the rocker arm 20 so as to be displaceable in the length direction of the hole. Specifically, the pin hole 41 penetrates in the axial direction on the axis of the bottomed hole-shaped first hole 42 recessed in the inner peripheral surface of the mounting hole 24 of the arm body 21 and the input roller 28 of the displacement member 26. A through hole-shaped second hole 43 provided, and a bottomed-hole-shaped third hole 44 that is recessed on the inner peripheral surface of the mounting hole 24 of the arm body 21 and is opposed to the first hole 42. ing. The connecting pin 45 is housed in the second hole 43 when in the disconnected state, the first pin 46 straddling between the first hole 42 and the second hole 43 when in the connected state, and the connected pin 45 when in the disconnected state. The second pin 47 is housed in the third hole 44 and includes a second pin 47 straddling between the second hole 43 and the third hole 44 when connected. The first pin 46 also serves as a rotation shaft of the input roller 28. Therefore, a hollow shaft or the like that supports the input roller 28 is provided between the first pin 46 and the input roller 28. It is not intervened separately. Therefore, the number of parts is reduced from this, so that the structure of the displacement member 26 is simplified as much as possible.

  The spring 48 is a member for pressing the connecting pin 45 toward the first hole 42, and is interposed between the bottom surface of the third hole 44 and the second pin 47.

  The hydraulic mechanism 51 is a mechanism for pressing the connecting pin 45 toward the third hole 44. The hydraulic mechanism 51 includes a hydraulic chamber 53 provided inside the arm body 21 that drives the connecting pin 45 with hydraulic pressure, and an oil passage 54 that supplies hydraulic pressure to the hydraulic chamber 53. Specifically, the hydraulic mechanism 51 includes a hydraulic pin 52 that closes the first hole 42 between the bottom surface of the first hole 42 and the first pin 46. The aforementioned hydraulic chamber 53 is formed therebetween. The oil passage 54 communicates with the hydraulic chamber 53, and the oil passage 54 passes through the cylinder head 6, one lash adjuster 30, the fulcrum pin 32, and the inside of the arm body 21. The hydraulic mechanism 51 changes the hydraulic pressure supplied from the oil passage 54 to the hydraulic chamber 53, and changes the hydraulic pressure in the hydraulic chamber 53 to cooperate the spring 48 with the connecting pin 45 in one direction and the above. Drive in the other direction.

  A portion including the opening of the first hole 42 and the opening of the third hole 44 on the inner peripheral surface of the mounting hole 24 has a width extending in the length direction (substantially vertical direction) of the mounting hole 24. Pin grooves 24a that are substantially equal to the width of one pin 46 (larger by the clearance) are respectively recessed, and when the connection is released, both ends of the first pin 46 enter inside the both pin grooves 24a. The displacement member 26 is prevented from rotating in a substantially horizontal plane. A roller groove 24b for accommodating the outer peripheral portion of the input roller 28 is recessed in a portion corresponding to the locus of the outer peripheral portion of the input roller 28 provided on the inner peripheral surface of the mounting hole 24. .

  The state of the variable valve mechanism 9 described above will be described below separately for (1) when the internal combustion engine is rotating at a low speed and (2) when the internal combustion engine is rotating at a high speed.

(1) During low-speed rotation of the internal combustion engine At this time, as shown in FIG. 3A, when the hydraulic pressure in the hydraulic chamber 53 increases, the two pins 46 and 47 are connected via the hydraulic pin 52 with the hydraulic pressure. The connecting pin 45 is driven toward the third hole 44 against the pressing force of the spring 48. At this time, the hydraulic pin 52 is accommodated in the first hole 42, the first pin 46 is accommodated in the second hole 43, and the second pin 47 is accommodated in the third hole 44. Therefore, neither the first pin 46 nor the second pin 47 crosses between the holes 42, 43, 44, so that the connection is released, and the displacement member 26 is in a substantially vertical direction with respect to the arm body 21. Relative displacement is possible. Therefore, at this time, as shown in FIGS. 4A and 4B, the displacement member 26 repeats relative displacement up and down with respect to the arm body 21 in accordance with the rotation of the rotary cam 10. At this time, in this embodiment, the valve spring 8 is sufficiently stronger than the lost motion spring 29, and the stroke in which the displacement member 26 can be relatively displaced with respect to the arm body 21 is secured sufficiently long. The valve 7 is not driven at all, and therefore the valve 7 is in a drive stop state. Therefore, in this disengaged state, half of the cylinders 5 in which the variable valve mechanism 9 is installed are not inhaled, so that the internal combustion engine is operated by the output from only the remaining half of the cylinders. To do.

(2) During high-speed rotation of the internal combustion engine At this time, as shown in FIG. 3 (b), the hydraulic pressure in the hydraulic chamber 53 decreases, so that the connecting pin 45 composed of the two pins 46 and 47 is pushed by the spring 48. The pressure is pushed back to the first hole 42 side. At this time, the first pin 46 is arranged at a position straddling between the first hole 42 and the second hole 43, and the second pin 47 is at a position straddling between the second hole 43 and the third hole 44. It will be arranged and will be in a connection state by these. Therefore, at this time, as shown in FIGS. 4C and 4D, the rocker arm 20 has the arm body 21 and the displacement member 26 that follow the rotation of the rotary cam 10 around the base end 21 a of the arm body 21. It swings integrally, and the valve 7 is pressed downward and driven by the output surface 23 of the tip 21b of the arm body 21. For this reason, in this connected state, intake is also performed to the cylinder 5 in which the variable valve mechanism 9 is installed, and the internal combustion engine is operated by the output from all the cylinders.

  According to the present embodiment, the rocker arm 20 includes the arm main body 21 and the displacement member 26 attached to the main body. Therefore, as in the conventional example 1, it is necessary to provide two rocker arms, as in the conventional example 2. In addition, it is not necessary to make the rocker arm a double structure consisting of an outer arm and an inner arm, and the structure of the rocker arm 20 is simplified.

  Further, since the switching mechanism 40 includes the hydraulic chamber 53 inside the arm body 21, there is no need to separately provide a pin driving mechanism for driving the connecting pin 45 outside the rocker arm 20 as in the conventional examples 1 and 2. Therefore, the structure of the switching mechanism 40 is also simplified.

  Further, an oil passage 54 of the switching mechanism 40 is provided via the hydraulic lash adjuster 30, so that an oil passage 54 for the switching mechanism 40 and an oil passage for the lash adjuster 30 are provided. As a result, the structure of the variable valve mechanism 9 is simplified.

  The variable valve mechanism shown in FIG. 5 of the second embodiment is substantially the same as that of the first embodiment, but only the switching mechanism 60 is different from the switching mechanism 40 of the first embodiment. That is, contrary to the first embodiment, the switching mechanism 60 is connected by driving the connecting pin 45 in one direction with the hydraulic pressure of the hydraulic mechanism 51, loosening the hydraulic pressure and pressing in the other direction with the pressing force of the spring 48. To the disconnected state. Only differences from the first embodiment will be described below.

  The connecting pin 65 of the switching mechanism 60 is housed in the first hole 42 when in the disconnected state, and the first pin 66 straddling between the first hole 42 and the second hole 43 when in the connected state, and the disconnected state. Is contained in the second hole 43, and in the connected state, the second pin 67 straddling between the second hole 43 and the third hole 44 is included. The hydraulic chamber 53 of the hydraulic mechanism 51 is formed between the bottom surface of the first hole 42 and the first pin 66 that also serves as a hydraulic pin that closes the first hole 42. The switching mechanism 60 includes a pressing pin 69 that presses the second pin 67 closer to the third hole 44 than the second pin 67, and the spring 48 has a bottom surface of the pressing pin 69 and the third hole 44. It is intervened between.

  The state of the variable valve mechanism 9 described above will be described below separately for (1) when the internal combustion engine is rotating at a low speed and (2) when the internal combustion engine is rotating at a high speed.

(1) When the internal combustion engine rotates at a low speed At this time, as shown in FIG. 5A, the hydraulic pressure in the hydraulic chamber 53 decreases, so that the connecting pin 65 composed of the two pins 66 and 67 is pushed by the spring 48. It is pushed back to the first hole 42 side by the pressure via the pressing pin 69. At this time, the first pin 66 is accommodated in the first hole 42, the second pin 67 is accommodated in the second hole 43, and the pressing pin 69 is accommodated in the third hole 44. Therefore, neither the first pin 66 nor the second pin 67 crosses between the holes 42, 43, 44, so that the connection is released.

(2) During high-speed rotation of the internal combustion engine At this time, as shown in FIG. 5B, when the hydraulic pressure in the hydraulic chamber 53 increases, the connection pin 65 including the two pins 66 and 67 is caused by the hydraulic pressure. It is driven toward the third hole 44 against the pressing force of the spring 48. At this time, the first pin 66 is arranged at a position straddling between the first hole 42 and the second hole 43, and the second pin 67 is at a position straddling between the second hole 43 and the third hole 44. It will be arranged and will be in a connection state by these.

  According to the second embodiment, contrary to the first embodiment, the connected state can be set when the hydraulic pressure is increased, and the disconnected state can be set when the hydraulic pressure is decreased.

  In addition, this invention is not limited to the structure of the said Example 1, 2, It can also be changed and embodied in the range which does not deviate from the meaning of invention, For example, like the following modifications 1-4 It may be changed.

[Modification 1]
As shown in FIGS. 6A and 6B, the lost motion spring 29 is replaced with a stronger lost motion spring 71 or a stopper for restricting the displacement of the displacement member 26 is provided. The stroke of the displacement member 26 that can be displaced relative to the arm body 21 at this time is made shorter than the stroke in the first and second embodiments, so that the driving of the valve 7 is completely stopped even in the disconnected state. Instead, the valve 7 may be driven with a lift amount smaller than that in the connected state.

[Modification 2]
As shown in FIG. 6 (c), an oscillation center portion is provided in the middle portion in the longitudinal direction of the arm body 72 different from the arm body 21 of the embodiment, and the displacement member 26 is disposed at the rear end of the arm body 72. The displacement member 26 may be driven by being pressed from below by the rotating cam 10.

[Modification 3]
As shown in FIG. 6 (d), by aligning the width of the roller groove 24b to be substantially equal to the width of the input roller 28 (larger by the clearance), the roller groove 24b and the input roller 28 are used to form the displacement member 26. You may prevent rotation in a horizontal plane. In this case, the end surface 46e of the first pin 46 is rounded into a curved surface so that the end surface 46e is continuous with the outer peripheral surface of the displacement member 26 when in the disconnected state, and the pin groove 24a is eliminated. You may try to save space.

[Modification 4]
As shown in FIG. 6 (e), a pad 73 may be attached to the stem end 7e of the valve 7 so as to suppress wear.

It is a perspective view which shows the variable valve mechanism of Example 1 of this invention. It is a disassembled perspective view which shows the variable valve mechanism of the Example. In the same Example, (a) is a plane sectional view which shows a mode when an arm main body and a displacement member are a connection cancellation | release state, (b) is a plane sectional view which shows a mode at the time of a connection state. In the same Example, (a) and (b) are side views showing the state when the arm body and the displacement member are in the disconnected state, and (c) and (d) are side views showing the state when in the connected state. It is. In Example 2, (a) is a plane sectional view which shows a mode when an arm main body and a displacement member are a connection cancellation | release state, (b) is a plane sectional view which shows a mode at the time of a connection state. (A) (b) (c) which shows the example of a change of Example 1, 2 is side sectional drawing, (d) is plane sectional drawing, (e) is a perspective view. (A) is a perspective view which shows the variable valve mechanism of the prior art example 1, (b) is a perspective view which shows the variable valve mechanism of the prior art example 2. FIG.

Explanation of symbols

7 Valve 9 Variable valve mechanism 10 Rotating cam 20 Rocker arm 21 Arm body 26 Displacement member 27 Displacement member body portion 28 Input roller 40 Switching mechanism 45 Connecting pin 53 Hydraulic chamber 54 Oil passage

Claims (3)

In a variable valve mechanism (9) for changing the opening / closing amount of the valve (7) by operating a rocker arm (20) interposed between a rotary cam (10) and a valve (7) so as to be swingable. ,
The rocker arm (20) includes an arm main body (21) including a swinging central portion of the arm and a portion in contact with the valve (7), and a portion in contact with the rotating cam (10). 21) and a displacement member (26) that is linearly attached to the main body so as to be capable of relative displacement in the pressing direction by the rotary cam (10).
A connection state in which the arm main body (21) and the displacement member (26) are connected to each other so that the relative displacement is impossible, and a connection release state in which the connection is released to enable the relative displacement. A switching mechanism (40) for switching between the two, the switching amount of the valve (7) is changed by the switching,
The switching mechanism (40) is housed in the displacement member (26) in the disconnected state, and a pin (between the arm body (21) and the displacement member (26) in the connected state ( 46), a hydraulic chamber (53) provided inside the arm body (21) for driving the pin (46) with hydraulic pressure, and an oil passage (54) for supplying the hydraulic pressure to the hydraulic chamber (53) )
An input roller (28) that contacts the rotating cam (10) of the displacement member (26) is rotatably supported by the pin (46) ,
The arm body (21) includes a mounting hole (24) extending in the displacement direction of the displacement member (26), and the displacement member (26) is mounted in the mounting hole (24).
A pair of pin grooves (24a, 24a) extending in the displacement direction of the displacement member (26) and having a width substantially equal to the width of the pin (46) are recessed in the inner surface of the mounting hole (24). In the disengaged state, both ends of the pin (46) enter the inside of the pair of pin grooves (24a, 24a) to prevent the displacement member (26) from rotating. Variable valve mechanism.   The switching mechanism (40) is housed in the arm main body (21) when in the disengaged state with the first pin (46) as the pin (46), and in the connected state, the arm main body (21). ) And the displacement member (26), the second pin (47), the hydraulic chamber (53) for hydraulically driving the first pin (46) and the second pin (47), The variable valve mechanism according to claim 1, comprising the oil passage (54).   The variable valve mechanism according to claim 1 or 2, wherein a main body portion of the displacement member (26) excluding the input roller (28) has a substantially columnar shape.

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