JP2008075479A - Valve gear for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To compact a valve gear and reduce cost thereof without uselessly increasing rigidity. <P>SOLUTION: In the valve gear for an internal combustion engine provided with a first cam follower oscillating with following a first cam provided on a camshaft, a second cam follower following the second cam having larger projection quantity from a base circle part than the first cam and provided on the camshaft, a first cam follower connected and interlocked with an engine valve energized by a spring in a valve close direction, a first connecting pin capable of changing over connection and disconnection of the first and a third cam follower, and a second connecting pin capable of changing over connection and disconnection of the second and the third cam follower, rigidity of the second connecting pin 34 is established higher than rigidity of the first connecting pin 33. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention provides a first cam follower that swings following the first cam provided on the camshaft, and a second cam provided on the camshaft with a protruding amount from the base circle portion larger than that of the first cam. A second cam follower driven by a cam, a first cam follower linked and connected to an engine valve spring-biased in a valve closing direction, and a first connection pin capable of switching between connection and release of the first and third cam followers Further, the present invention relates to a valve operating apparatus for an internal combustion engine including a second connecting pin that can switch connection and disconnection of the second and third cam followers.

Such a valve operating apparatus for an internal combustion engine is already known from Japanese Patent Application Laid-Open No. 2005-228867.
Japanese Patent Publication No. 2-50284

  By the way, in the connected state of the first and third cam followers by the first connecting pin, the engine valve opens and closes with an operating characteristic corresponding to the cam profile of the first cam, and the connected state of the second and third cam followers by the second connecting pin. In this case, the engine valve opens and closes with an operation characteristic corresponding to the cam profile of the second cam, and the valve opening lift amount of the engine valve based on the cam profile of the second cam is the valve opening degree of the engine valve based on the cam profile of the first cam. Greater than lift amount. For this reason, the load which acts on the 2nd connection pin which connects the 2nd and 3rd cam follower is larger than the load which acts on the 1st connection pin which connects the 1st and 3rd cam follower. However, in the conventional valve gear as disclosed in Patent Document 1, there is no difference in the rigidity of the connecting pins, and all the connecting pins are made of the same material and have the same diameter. There is a part to secure.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a valve operating apparatus for an internal combustion engine that can achieve cost reduction and downsizing without wastefully increasing rigidity.

  In order to achieve the above object, the invention according to claim 1 is characterized in that the first cam follower that swings following the first cam provided on the camshaft, and the amount of protrusion from the base circle portion is smaller than that of the first cam. A second cam follower driven by a second cam provided on the camshaft, a third cam follower coupled to and coupled to an engine valve biased in the valve closing direction, and a first cam follower and a third cam follower. In a valve operating apparatus for an internal combustion engine, comprising: a first connection pin that can switch connection and release, and a second connection pin that can switch connection and release of the second and third cam followers. The first connecting pin is set to be higher than the rigidity of the first connecting pin.

  According to a second aspect of the invention, in addition to the configuration of the first aspect of the invention, the second connecting pin is formed with a larger diameter than the first connecting pin.

  According to a third aspect of the invention, in addition to the configuration of the second aspect of the invention, the first to third cam followers are arranged adjacent to each other so as to sandwich the third cam follower between the first and second cam followers, and are formed in a cylindrical shape. The second connecting pin is inserted into and fitted into the second cam follower to connect the second and third cam followers, and to move between the positions to release the connection with the second cam followers. It is slidably fitted, and the first connecting pin enters the first cam follower and moves between the position where the first and third cam followers are connected and the position where the connection with the first cam follower is released. The second connecting pin is slidably fitted to the second connecting pin, and the first connecting pin released from the first cam follower is brought into contact with the second cam follower side of the second connecting pin. The second cam follower is provided on the first cam follower side of the third cam follower with a second restricting portion that abuts the second connecting pin released from the connection with the second cam follower, and the first cam follower includes the first connecting follower. A first regulating piston that contacts the pin is slidably fitted to the first cam follower so as to form a first hydraulic chamber, and the second cam follower is in contact with the second connecting pin. The second regulating piston forms a second hydraulic pressure chamber with the second cam follower, and a third hydraulic pressure chamber communicating with the second hydraulic pressure chamber is formed between the first connecting pin and the second connecting pin. The first hydraulic pressure chamber accommodates a first return spring that is contracted between the first restriction piston and the first cam follower, and the second hydraulic pressure chamber includes a second restriction piston and A second return spring that is contracted between the second cam followers Characterized in that it is housed.

  According to a fourth aspect of the present invention, in addition to the configuration of the third aspect of the present invention, the second restriction piston is provided with a communication passage coaxially connecting the second and third hydraulic pressure chambers. The inner diameter of the communication path is set so that the communication path exists in the inner periphery of the end of the second connecting pin on the second cam follower side when viewed in the axial direction even in a state where relative swing is generated in the three cam follower. Features.

  Furthermore, in the invention described in claim 5, in addition to the configuration of the invention described in claim 3 or 4, the second restricting portion is provided in the third cam follower so as to slidably fit the second connecting pin. The second connecting pin is formed in a hook shape projecting radially inward from the first cam follower side end of the sliding hole, and the inner diameter of the second restricting portion is fitted to the first connecting pin so as to be relatively slidable. It is characterized by being set larger than the inner diameter.

  The intake valve 11 of the embodiment corresponds to the engine valve of the present invention, the low speed cam 14 of the embodiment corresponds to the first cam of the present invention, and the high speed cam 15 of the embodiment corresponds to the second cam of the present invention. Correspondingly, the first to third rocker arms 17 to 19 correspond to the first to third cam followers of the present invention.

  According to the first aspect of the present invention, the rigidity of the second connecting pin for connecting the second and third cam followers with a large lift amount of the engine valve is made small, and the lift amount of the engine valve is made small. By setting the rigidity higher than the rigidity of the first connection pin that connects the first and third cam followers, the rigidity of the second connection pin can be sufficiently ensured, and the necessary rigidity of the first connection pin can be ensured. However, the cost can be reduced without unnecessarily increasing the rigidity of the first connecting pin.

  According to the second aspect of the invention, it is possible to reduce the size and weight of the first cam follower to be connected while securing the necessary rigidity of the first connecting pin, and to sufficiently ensure the rigidity of the second connecting pin. Can be secured.

  According to the third aspect of the present invention, the first and second connecting pins are fitted so as to be slidable relative to each other and disposed on the third cam follower. The size of the third cam follower can be reduced. In addition, since the first connecting pin has a small diameter, the sliding resistance can be kept small, and the first connecting pin is inserted and fitted into the first cam follower to enhance the responsiveness when connecting the first and third cam followers. Can do.

  According to the fourth aspect of the present invention, the second hydraulic pressure chamber and the third hydraulic pressure chamber can be reliably communicated even when the second and third cam followers are relatively swung.

  Furthermore, according to the fifth aspect of the present invention, the moving end of the second connecting pin toward the first cam follower can be regulated without affecting the sliding of the first connecting pin.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on one embodiment of the present invention shown in the accompanying drawings.

  1 to 4 show an embodiment of the present invention. FIG. 1 is a longitudinal sectional view of a main part of a valve operating apparatus for an intake valve, which is a sectional view taken along line 1-1 of FIG. 3 is a sectional view taken along line 2-2 of FIG. 1, FIG. 3 is a sectional view taken along line 3-3 of FIG. 2, and FIG. 4 is a sectional view sequentially showing changes in the operating state of the connection switching mechanism as viewed from the same direction as FIG.

  First, in FIG. 1 to FIG. 3, an intake valve 11 that is an engine valve is a raised portion 13 provided on a camshaft 12 that is driven to rotate at a rotation ratio of ½ in synchronization with the rotation of the engine, and a first cam. The first to third rocker arms 17 which are the first to third cam followers supported so as to be swingable by a certain low speed cam 14 and the high speed cam 15 which is the second cam, and the rocker shaft 16 parallel to the cam shaft 12. , 18 and 19 are opened and closed by the action.

  The raised portion 13 is provided on the camshaft 12 at a position corresponding to the intake valve 11, and the low speed cam 14 and the high speed cam 15 are provided on the camshaft 12 on both sides of the raised portion 13. Moreover, the raised portion 13 is formed in a perfect circle shape corresponding to the base circle portions 14a and 15a of the low-speed cam 14 and the high-speed cam 15, and the low-speed cam 14 and the high-speed cam 15 are connected to the base circle portions 14a and 15a. And high-level portions 14b and 15b projecting radially outward from the base circle portions 14a and 15a, respectively, and the high-level portions 15b of the high-speed cam 15 project radially outward from the base circle portion 15a. The amount is larger than the protruding amount of the high-order part 14b of the low-speed cam 14 from the base circle part 14a, and is formed so as to cover a wider central angle range than the high-order part 14b of the low-speed cam 14.

  The first to third rocker arms 17 to 19 are arranged adjacent to each other so that the third rocker arm 19 is sandwiched between the first and second rocker arms 17 and 18. An intermediate portion of the third rocker arm 19 having a cam slipper 19a slidably in contact with the raised portion 13 of the camshaft 12 is supported by the rocker shaft 16 so as to be able to swing, and is advanced and retracted to the other end portion of the third rocker arm 19. A tappet screw 20 screwed so as to be adjustable is brought into contact with the valve stem 11a of the intake valve 11 urged by the valve spring 21 in the valve closing direction.

  The first rocker arm 17 comprises a rocker arm main body 23 whose middle part is supported so as to be swingable by the rocker shaft 16, and a cylindrical tube shaft 24 fitted and fixed to the rocker arm main body 23 by press fitting or the like. One end side of the rocker arm main body 23 has a pair of support walls 23a and 23b facing each other and is bifurcated, and the cylindrical shaft 24 is provided between the support walls 23a and 23b. In addition, a roller 26 is supported on the cylindrical shaft 24 via a needle bearing 25 between the support walls 23 and 23b, and the roller 26 is brought into contact with the low-speed cam 14.

  The second rocker arm 18 includes a rocker arm main body 27 whose middle part is supported by the rocker shaft 16 so as to be swingable, and a cylindrical tube shaft 28 fitted and fixed to the rocker arm main body 27 by press-fitting or the like. One end side of the rocker arm main body 27 has a pair of support walls 27a and 27b opposed to each other and is bifurcated, and the cylindrical shaft 28 is provided between the support walls 27a and 27b. . In addition, a roller 30 is supported on the cylindrical shaft 28 via a needle bearing 29 between the support walls 27a and 27b, and the roller 30 is brought into contact with the high-speed cam 15.

  Between the other end portions of the first and second rocker arms 17 and 18 and the cylinder head 31 of the engine body, the first roller 26 and 30 are arranged on the side where they abut against the low speed cam 14 and the high speed cam 15. In addition, resilient means 54 and 55 (see FIG. 2) for urging the second rocker arms 17 and 18 are provided.

  The first to third rocker arms 17 and 19 are connected to the first rocker arm 17 in the first state where the third rocker arm 19 is not connected to any of the first and second rocker arms 17 and 18. A connection switching mechanism 32 that can switch between the second state and the third state in which the third rocker arm 19 is connected to the second rocker arm 18 is provided. Thus, in the first state, the third rocker arm 19 swings while being in contact with the raised portion 13 of the camshaft 12, so that the intake valve 11 remains closed. Therefore, in a multi-cylinder internal combustion engine in which one intake valve 11 is disposed per cylinder, the cylinder is deactivated when the intake valve 11 is closed. In the second state, the third rocker arm 19 swings together with the first rocker arm 17 driven by the low speed cam 14, and the intake valve 11 is driven to open and close with an operating characteristic corresponding to the cam profile of the low speed cam 14. Further, in the third state, the third rocker arm 19 swings together with the second rocker arm 18 driven by the high-speed cam 15, and the intake valve 11 is driven to open and close with an operating characteristic corresponding to the cam profile of the high-speed cam 15. The valve opening lift amount of the intake valve 11 in the state 3 is larger than the valve opening lift amount in the second state according to the cam profile of the low speed cam 14.

  The connection switching mechanism 32 includes a first connection pin 33 that can switch connection and disconnection of the first and third rocker arms 17 and 19, and a first connection pin 33 that is more rigid than the first connection pin 33. Is formed in a large-diameter cylindrical shape so that the first connecting pin 33 is fitted to be slidable and the second and third rocker arms 18 and 19 can be switched between connection and release, and slides on the third rocker arm 19. A second connecting pin 34 that can be fitted, a first regulating piston 35 that is slidably fitted to the first rocker arm 17 so as to contact the first connecting pin 33, and a second connecting pin 34 A second restriction piston 36 slidably fitted to the second rocker arm 18 so as to abut, a first return spring 37 contracted between the first restriction piston 35 and the first rocker arm 17, and a first And a second return spring 38 mounted under compression between regulation piston 36 and the second rocker arm 18, the spring load of the second return spring 38 is set larger than the spring load of the first return spring 37.

  The third rocker arm 19 is provided with a sliding hole 40 having both ends opened, and the second connecting pin 34 is slidably fitted into the sliding hole 40. In addition, the first connecting pin 33 in a state in which the connection with the first rocker arm 17 is released is brought into contact with the end of the second connecting pin 34 on the second rocker arm 18 side so that the second rocker arm of the first connecting pin 33 is brought into contact. A first restricting portion 41 that restricts movement toward the 18th side is integrally provided in a hook shape projecting inward in the radial direction. The third rocker arm 19 is integrally provided with a hook-like second restricting portion 42 that projects inward in the radial direction from the end of the sliding hole 40 on the first rocker arm 17 side. The second connecting pin 34 in a state where the connection with the second connecting pin 34 is in contact with the second restricting portion 42 restricts the movement of the second connecting pin 34 toward the first rocker arm 17. Moreover, the inner diameter of the second restricting portion 42 is set larger than the inner diameter of the second connecting pin 34.

  The inner diameter of the cylindrical shaft 24 in the first rocker arm 17 is set to a value that allows the first connecting pin 33 to be slidably fitted, and the first regulating piston 35 that contacts the first connecting pin 33 is the first A first hydraulic pressure chamber 43 is formed between the rocker arm 17 and slidably fitted to the cylindrical shaft 42, and the first return spring 37 is accommodated in the first hydraulic pressure chamber 43.

  The inner diameter of the cylindrical shaft 28 in the second rocker arm 18 is set to a value that allows the second connecting pin 34 to be slidably fitted, and the second regulating piston 36 that contacts the second connecting pin 34 has the second A second hydraulic pressure chamber 44 is formed between the rocker arm 18 and slidably fitted to the cylindrical shaft 28, and the second return spring 38 is accommodated in the second hydraulic pressure chamber 44.

  A third hydraulic pressure chamber 45 is formed between the second restricting piston 36 and the first connection pin 33 in the second connection pin 34, and the communication path communicates between the second and third hydraulic pressure chambers 44, 45. 46 is provided coaxially with the second regulating piston 36. Moreover, the inner diameter of the communication path 46 is the second rocker arm of the second connecting pin 34 when viewed in the axial direction in a state in which the second and third rocker arms 18 and 19 are not connected to each other. The communication path 46 is set so as to exist in the inner periphery of the 18 side end, that is, in the inner periphery of the first restricting portion 41.

  The rocker shaft 16 is provided with first and second hydraulic pressure passages 47 and 48 that are capable of switching and controlling the action and release of the hydraulic pressure. A first passage 49 that communicates with the hydraulic chamber 43 is provided in the first rocker arm 17, and a second passage 50 that communicates the second hydraulic passage 48 with the second hydraulic chamber 44 is provided in the second rocker arm 18.

  According to such a connection switching mechanism 32, when both the hydraulic pressures of the first and second hydraulic pressure paths 47 and 48 are released, the second return spring 38 is attached with a spring as shown in FIG. The second connecting pin 34 pressed by the biased second restricting piston 36 is in a position where it abuts the second restricting portion 42 and is pressed by the first restricting piston 35 biased by the first return spring 37. The first connecting pin 33 is in a position where it abuts against the first restricting portion 41. In this state, the abutting surfaces of the first connecting pin 33 and the first restricting piston 35 correspond to positions between the first and third rocker arms 17, 19. The contact surfaces of the second connecting pin 34 and the second restricting piston 36 are in positions corresponding to between the second and third rocker arms 18 and 19.

  Next, when the hydraulic pressure is applied to the second hydraulic pressure passage 48 with the hydraulic pressure of the first hydraulic pressure passage 47 released, the third hydraulic pressure is supplied from the second hydraulic pressure chamber 44 as shown in FIG. When the hydraulic pressure acts on the chamber 45, the first connecting pin 33 enters the first rocker arm 17 while being pushed into the first rocker arm 17 against the spring force of the first return spring 37. Therefore, the roller 26 of the first rocker arm 17 contacts the base circle portion 14a of the low speed cam 14, and the cylindrical shaft 24 of the first rocker arm 17 and the sliding hole 40 of the third rocker arm are coaxial. The first connecting pin 33 pushes in the first regulating piston 35 to enter and fit into the first rocker arm 17, and the third rocker arm 19 is connected to the first rocker arm 17. At this time, the first regulating piston 35 is moved toward the side of reducing the volume of the first hydraulic pressure chamber 43 so that the first connecting pin 33 is located between the third rocker arm 19 and the first rocker arm 17. The end is regulated by the first rocker arm 17.

  Further, when the hydraulic pressure in the second hydraulic pressure passage 48 is released and the hydraulic pressure is applied to the first hydraulic pressure passage 47, the hydraulic pressure is applied to the first hydraulic pressure chamber 43 as shown in FIG. As a result, the first connecting pin 33 is pressed by the first restricting piston 35 on the side pushed toward the second rocker arm, and the first connecting pin 33 comes into contact with the first restricting portion 41 so that the first connecting pin 33 contacts the first connecting pin 33. The pin 33 presses the second connecting pin 34, and the second connecting pin 34 pushes the second regulating piston 36 and enters and fits into the second rocker arm 18, and the third rocker arm 19 moves to the second rocker arm 18. Connected to At this time, the second regulating piston 36 is moved toward the side of reducing the volume of the second hydraulic pressure chamber 44 so that the second connecting pin 34 is positioned between the third rocker arm 19 and the second rocker arm 18. The end is regulated by the second rocker arm 18.

  Next, the operation of this embodiment will be described. When the first and third rocker arms 17 and 19 are connected by the first connecting pin 33, the intake valve 11 opens and closes with an operating characteristic corresponding to the cam profile of the low speed cam 14. When the second and third rocker arms 18 and 19 are connected by the second connecting pin 34, the intake valve 11 opens and closes with an operating characteristic corresponding to the cam profile of the high-speed cam 15, and is based on the cam profile of the high-speed cam 15. Since the valve opening lift amount of the intake valve 11 is larger than the valve opening lift amount of the intake valve 11 based on the cam profile of the low speed cam 14, the valve opening lift amount is connected to the second connecting pin 34 connecting the second and third rocker arms 18 and 19. The acting load is larger than the load acting on the first connecting pin 33 that connects the first and third rocker arms 17 and 19. However, since the rigidity of the second connecting pin 34 is set higher than that of the first connecting pin 33, the rigidity of the second connecting pin 34 can be sufficiently secured, and the necessary rigidity of the first connecting pin 33 can be ensured. However, the cost can be reduced without unnecessarily increasing the rigidity of the first connecting pin 33.

  Moreover, since the second connecting pin 34 is formed to have a larger diameter than the first connecting pin 33, the first rocker arm 17 to be connected is small and lightweight while ensuring the necessary rigidity of the first connecting pin 33. The second connecting pin 34 can be sufficiently rigid.

  The first to third rocker arms 17 to 19 are arranged adjacent to each other so that the third rocker arm 19 is sandwiched between the first and second rocker arms 17 and 18, and the cylindrical second connecting pin 34 enters the second rocker arm 18. It is slidably fitted to the third rocker arm 19 so as to be able to move between a position where the second and third rocker arms 18 and 19 are connected and a position where the connection with the second rocker arm 18 is released, The first connecting pin 33 enters and fits into the first rocker arm 17 so as to be movable between a position where the first and third rocker arms 17 and 19 are connected and a position where the connection with the first rocker arm 17 is released. The second connecting pin 34 is fitted so as to be slidable relative to the second rocker arm 18 side of the second connecting pin 34, and the first rocker arm 17 is disconnected from the first rocker arm 17. A first restricting portion 41 that abuts the linking pin 33 is provided, and a second linking pin 34 that is disconnected from the second rocker arm 18 is abutted on the first rocker arm 17 side of the third rocker arm 19. A restricting portion 42 is provided, and the first rocker arm 17 slides so that the first restricting piston 35 contacting the first connecting pin 33 forms a first hydraulic pressure chamber 43 between the first rocker arm 17 and the first rocker arm 17. The second rocker arm 18 is fitted to the second rocker arm 18, and the second restricting piston 36 contacting the second connecting pin 34 forms a second hydraulic pressure chamber 44 between the second rocker arm 18 and the second hydraulic pressure. A third hydraulic pressure chamber 45 communicating with the chamber 44 is slidably fitted in the second connection pin 34 so as to be formed between the first connection pin 33 and the first hydraulic pressure chamber 43 in the first hydraulic pressure chamber 43. Regulating piston 35 and first rocker A first return spring 37 that is contracted between 17 is accommodated, and a second return spring 38 that is contracted between the second regulating piston 36 and the second rocker arm 18 is accommodated in the second hydraulic pressure chamber 44. .

  That is, the first and second connecting pins 33 and 34 are fitted so as to be slidable relative to each other and disposed on the third rocker arm 19, and in a direction along the axis of the first and second connecting pins 33 and 34. The size of the third rocker arm 19 can be reduced. Moreover, since the first connecting pin 33 has a small diameter, the sliding resistance can be kept small. When the first connecting pin 33 is inserted into and fitted into the first rocker arm 17, the first and third rocker arms 17 and 19 are connected. Can increase the responsiveness.

  The second restricting piston 36 is provided with a communication passage 46 connecting the second and third hydraulic pressure chambers 44 and 45 coaxially to the second and third rocker arms 18 and 19 which are not connected to each other. Since the internal diameter of the communication path 46 is set so that the communication path 46 exists in the inner periphery of the end of the second connection pin 34 on the second rocker arm 18 side when viewed in the axial direction in a state where relative oscillation has occurred. The second hydraulic pressure chamber 44 and the third hydraulic pressure chamber 45 can be reliably communicated even when the second and third rocker arms 18 and 19 are relatively swung.

  Further, the second restricting portion 42 projects radially inward from the end portion on the first rocker arm 17 side of the sliding hole 40 provided in the third rocker arm 19 so that the second connecting pin 34 can be slidably fitted. Since the inner diameter of the second restricting portion 42 is set larger than the inner diameter of the second connecting pin 34 that is fitted to the first connecting pin 33 so as to be relatively slidable, the first connecting pin 33 is formed in a bowl shape. The moving end of the second connecting pin 34 toward the first rocker arm 17 can be restricted without affecting the sliding of the first connecting rocker 34.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various design changes can be made without departing from the present invention described in the claims. It is.

  For example, in the above embodiment, the intake valve 11 has been described as an engine valve. However, the present invention can also be implemented in connection with an exhaust valve that is an engine valve. The engine valve may be linked and connected to one of the second and third cam followers.

  Further, in order to increase the rigidity of the second connection pin as compared with the first connection pin, the first and second connection pins are made of materials having different rigidity, in addition to making the diameters of both the connection pins different as in the above-described embodiment. It may be formed, may be a hollow shape or a solid shape, and the hollowing amount in the hollow may be varied.

It is a principal part longitudinal cross-sectional view of the valve operating apparatus for intake valves, Comprising: It is the 1-1 sectional view taken on the line of FIG. FIG. 2 is a sectional view taken along line 2-2 of FIG. FIG. 3 is a sectional view taken along line 3-3 in FIG. 2. FIG. 4 is a cross-sectional view sequentially showing changes in the operating state of the connection switching mechanism as seen from the same direction as FIG. 3.

Explanation of symbols

11 ... Intake valve 12 as engine valve ... Cam shaft 14 ... Low speed cam 15 as first cam 15 ... High speed cam 15a as second cam ... Base circle 17 ... First rocker arm 18 as a first cam follower ... Second rocker arm 19 as a second cam follower ... Third rocker arm 33 as a third cam follower ... First connection pin 34 ... Second connection pin 35 ... first regulating piston 36 ... second regulating piston 37 ... first return spring 38 ... second return spring 41 ... first regulating part 42 ... second regulating part 43 ... First fluid pressure chamber 44 ... second fluid pressure chamber 45 ... third fluid pressure chamber 46 ... communication passage

Claims (5)

  The amount of protrusion from the first cam follower (17) that swings following the first cam (14) provided on the camshaft (12) and the base circle (15a) is larger than that of the first cam (14). Then, a second cam follower (18) driven by a second cam (15) provided on the camshaft (12) and an engine valve (11) spring-biased in the valve closing direction are coupled and connected to the second cam follower (18). 3 cam follower (19), first and third cam followers (17, 19), a first connecting pin (33) capable of switching connection and release, and second and third cam followers (18, 19) In the valve operating apparatus for an internal combustion engine including the second connection pin (34) capable of switching the connection release, the rigidity of the second connection pin (34) is set higher than the rigidity of the first connection pin (33). Of an internal combustion engine characterized by The valve device.   The valve operating apparatus for an internal combustion engine according to claim 1, wherein the second connecting pin (34) is formed to have a larger diameter than the first connecting pin (33).   The first to third cam followers (17 to 19) are arranged adjacent to each other so as to sandwich the third cam follower (19) between the first and second cam followers (17, 18), and are connected to a second connecting pin ( 34) enters and fits into the second cam follower (18) and can be moved between a position where the second and third cam followers (19) are connected and a position where the connection with the second cam follower (18) is released. The first cam follower (19) is slidably fitted to the third cam follower (19), and the first connecting pin (33) enters and fits into the first cam follower (17) to connect the first and third cam followers (19). The second cam follower of the second connecting pin (34) is fitted to the second connecting pin (34) so as to be movable between the position and the position where the connection with the first cam follower (17) is released. (1 ) Side is provided with a first restricting portion (41) for contacting the first connecting pin (33) released from the connection with the first cam follower (17), and the first cam follower (19) of the third cam follower (19) is provided. 17) is provided with a second restricting portion (42) that abuts the second connecting pin (34) that has been disconnected from the second cam follower (18), and the first cam follower (17) includes the second restricting portion (42). The first regulating piston (35) that contacts the one connecting pin (33) is slidably fitted so as to form a first hydraulic chamber (43) between the first cam follower (17), The second cam follower (18) has a second hydraulic pressure chamber (44) formed between the second restricting piston (36) contacting the second connecting pin (34) and the second cam follower (18). The third hydraulic chamber (45) leading to the two hydraulic chambers (44) is connected to the second series. In the pin (34), it is slidably fitted so as to be formed between the first connecting pin (33) and in the first hydraulic pressure chamber (43), the first regulating piston (35) and the first regulating piston (35). A first return spring (37) that is contracted between the cam followers (17) is accommodated, and the second hydraulic pressure chamber (44) is contracted between the second regulating piston (36) and the second cam follower (18). The valve operating apparatus for an internal combustion engine according to claim 2, wherein a second return spring (38) is accommodated.   The second regulating piston (36) is provided with a communication path (46) connecting the second and third hydraulic pressure chambers (44, 45) coaxially, and is relative to the second and third cam followers (18, 19). The communication path (46) so that the communication path (46) exists in the inner periphery of the end of the second connection pin (34) on the second cam follower (18) side when viewed in the axial direction even in a state where the oscillation occurs. The valve operating device for an internal combustion engine according to claim 3, wherein the inner diameter of the internal combustion engine is set.   The second restricting portion (42) is provided on the first cam follower (17) side of the sliding hole (40) provided in the third cam follower (19) so that the second connecting pin (34) is slidably fitted. The second connecting pin (34) is formed in a bowl shape projecting radially inward from the end, and the inner diameter of the second restricting portion (42) fits the first connecting pin (33) so as to be slidable relative to each other. The valve operating apparatus for an internal combustion engine according to claim 3 or 4, wherein the valve operating apparatus is set to be larger than an inner diameter of the internal combustion engine.

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