JP2007309272A - Variable valve train for internal combustion engine and its assembling method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent an engagement pin from being collided with an inner peripheral face of a support pipe while keeping a state that friction and vibration generated between a control shaft and a slider gear are easily released. <P>SOLUTION: A rotational phase difference variable mechanism 41 for a variable valve train 20 comprises the slider gear 44 engaged with an input part 21 and an output part 31, the control shaft 48 slid inside the support pipe 20x in the length direction, and a connection mechanism 52 constituted by engaging a slit hole 59 provided in the slider gear 44 with the engagement pin 53 mounted to a pin mounting hole 54 penetrated into the control shaft 48. The connection mechanism 52 is provided with a collision prevention means 55 which is constituted by engaging a C-ring 55c with both of an inner peripheral groove 55a recessed on the inner peripheral face of the pin mounting hole 54 and an outer peripheral groove 55b recessed on the outer peripheral face of the engagement pin 53 and limits relative displacement of the engagement pin 53 in the penetrating direction of the pin mounting hole 54 within a range of approximately 0.2 mm while allowing relative displacement of the engagement pin 53 in the circumferential direction of the pin mounting hole 54. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a variable valve mechanism that changes a valve lift amount, a working angle, and a timing continuously or stepwise in accordance with an operating state of an internal combustion engine.

  This type of variable valve mechanism includes an input unit 91 and an output unit 92 that are swingably supported side by side on the same support pipe 90x as in the variable valve mechanism 88 shown in FIG. When the input unit 91 is driven by the rotating cam 89, the intermediate drive mechanism 90 that drives the valve 8 by the output unit 92, and the rotational phase difference that fluctuates the relative rotational phase difference between the input unit 91 and the output unit 92. Some include a variable mechanism 93 (Patent Document 1).

The rotation phase difference variable mechanism 93 includes a slider gear 94 whose inner peripheral surface is in sliding contact with the support pipe 90x and whose outer peripheral portion is engaged with helical splines having different angles from each other between the input portion 91 and the output portion 92, and And a control shaft 95 that slides in the longitudinal direction F and R in the support pipe 90x. Then, the base end 96a of the engagement pin 96 is inserted and attached to the pin attachment hole 97 penetrating the control shaft 95, and the distal end 96b of the engagement pin 96 connects the support pipe 90x from the control shaft 95. The slider gear 94 is inserted into a circumferentially extending slit hole 98 provided in the slider gear 94 and slides into the inner side surfaces 98a and 98b so that the slider gear 94 is brought into contact with the control shaft 95 and the support pipe 90x. Are engaged in a slidable manner in the circumferential direction.
JP 2001-263015 A

  However, as described above, when the base end 96 a of the engagement pin 96 is merely inserted into the pin attachment hole 97, the engagement pin 96 freely moves in the penetrating directions V and W of the pin attachment hole 97. Therefore, when an external force or the like is applied, as shown in FIG. 9D, the base end 96a of the engagement pin 96 may violently collide with the inner peripheral surface of the support pipe 90x. is there. On the other hand, however, it is not preferable to completely fix the engagement pin 96 to the control shaft 95 because friction and vibration generated between the control shaft 95 and the slider gear 94 are difficult to escape.

  Therefore, an object is to prevent the engagement pin from colliding with the inner peripheral surface of the support pipe while keeping the friction and vibration generated between the control shaft and the slider gear easy to escape.

  In order to achieve the above object, a variable valve mechanism for an internal combustion engine according to a first aspect of the present invention includes an input portion and an output portion that are arranged on the same support pipe and are swingably supported. An internal combustion mechanism comprising an intermediate drive mechanism that drives a valve at the output unit when the input unit is driven, and a rotation phase difference variable mechanism that varies a relative rotation phase difference between the input unit and the output unit. In the variable valve mechanism of the engine, the rotation phase difference variable mechanism includes a slider gear that engages helical splines having different angles with each other between the input unit and the output unit, and a length inside the support pipe. A control shaft that slides in the vertical direction, and one end that is attached to a pin mounting hole that extends through the control shaft, and the other end that passes through the support pipe from the control shaft. A pair of engaging surfaces extending in the circumferential direction provided on the slider gear are engaged with the engaging pins protruding in the direction that are restrained in the length direction of the support pipe and slidable in the circumferential direction. A coupling mechanism, and the coupling mechanism is annularly recessed along an inner peripheral groove that is annularly recessed along the inner peripheral surface of the pin mounting hole and an outer peripheral surface of the engagement pin. An annular or substantially annular engagement member is engaged with both the outer circumferential groove and the relative movement in the penetration direction is prevented while allowing the relative movement of the pin mounting hole in the circumferential direction. And a collision preventing means for preventing one end of the engagement pin from colliding with the inner peripheral surface of the support pipe.

  The collision preventing means may completely prevent the relative movement of the engagement pin in the penetrating direction of the pin mounting hole, or restrict the relative movement to a specific range. May be.

  Although the said cyclic | annular or substantially cyclic | annular engagement member is not specifically limited, O ring, C ring, etc. are illustrated. Moreover, although the material of this engaging member is not specifically limited, various metals, various resin, etc. are illustrated.

  Although the said engagement pin is not specifically limited, It is preferable that it attaches with the space | interval between the end and the internal peripheral surface of the said support pipe. This is because the collision between the engagement pin and the support pipe can be prevented more reliably.

  The variable valve mechanism for an internal combustion engine according to the second aspect of the present invention includes an input portion and an output portion that are arranged on the same support pipe so as to be swingable, and the input portion is driven by a rotating cam. Then, a variable valve for an internal combustion engine comprising an intermediate drive mechanism that drives the valve by the output unit, and a rotation phase difference variable mechanism that varies a relative rotation phase difference between the input unit and the output unit. In the mechanism, the rotation phase difference variable mechanism slides in the length direction in the support pipe and a slider gear that engages helical splines having different angles with each other between the input unit and the output unit. One end of the control shaft is attached to a pin mounting hole penetrating the control shaft, and the other end of the engagement shaft projects from the control shaft through the support pipe and protrudes to the outside. A pair of engaging surfaces provided in the slider gear extending in the circumferential direction are constrained in the length direction of the support pipe and slidably engaged in the circumferential direction. The coupling mechanism restricts the relative movement of the engagement pin in the penetrating direction of the pin mounting hole within a range of 0.1 to 0.4 mm, and one end of the engagement pin is connected to the inside of the support pipe. A collision prevention means for preventing collision with the peripheral surface is provided.

  Although the said range is not specifically limited, It is more preferable that it is 0.1-0.3 mm, and it is most preferable that it is 0.15-0.25 mm. This is because, as the range is larger, vibration generated between the slider gear and the control shaft is more easily released, but stability is worsened if the range is too large.

Although the said collision prevention means is not specifically limited, The following (i) and (ii) are illustrated.
(I) The collision preventing means includes an engagement recess provided in one of an outer peripheral surface of the engagement pin and an inner peripheral surface of the pin mounting hole, and the engagement recess provided in the other. An engagement convex portion that engages with the pin, and allows relative movement of the engagement pin in the penetrating direction of the pin mounting hole between the engagement concave portion and the engagement convex portion within the range. A clearance is formed.
(Ii) The collision preventing means includes an engagement recess formed on both the outer peripheral surface of the engagement pin and the inner peripheral surface of the pin mounting hole, and the same engagement that engages with both the engagement recesses. A clearance that allows relative movement of the engagement pin in the penetrating direction of the pin mounting hole within the range is formed between any one of the engagement recesses and the engagement member. Things.

  In addition, since the 1st form and 2nd form of this invention are not mutually incompatible, you may incorporate the characteristic of both forms into the variable valve mechanism of the same internal combustion engine.

  The variable valve mechanism assembly method for an internal combustion engine according to the first aspect of the present invention includes an input portion and an output portion that are arranged on the same support pipe and supported so as to be swingable. An internal combustion engine comprising: an intermediate drive mechanism that drives a valve at the output unit when the unit is driven; and a rotation phase difference variable mechanism that varies a relative rotation phase difference between the input unit and the output unit. In the assembling method of the variable valve mechanism, the assembling method of the rotation phase difference varying mechanism is along the inner peripheral surface of the pin mounting hole penetrating the control shaft that slides in the length direction in the support pipe. A step of engaging an annular or substantially annular engaging member with an inner circumferential groove formed in an annular shape, and a slider gear that engages helical splines with different angles between the input portion and the output portion. Inside the support A step of inserting the pipe and the control shaft, and a mechanism of penetrating the support pipe and engaging the slider gear with the control shaft in the length direction of the support pipe and slidably engaging in the circumferential direction. The engaging pin is inserted and attached to the pin mounting hole while spreading the engaging member, and the engaging member is engaged with an outer peripheral groove that is annularly recessed along the outer peripheral surface of the engaging pin. And a process.

  Although the said engagement pin is not specifically limited, It is preferable to provide the chamfer which spreads the said engagement member when attaching the said engagement pin to the said pin attachment hole. This is because the mounting work becomes easy.

  The method of attaching the engagement pin is not particularly limited, but the engagement pin is connected to the inside of the slider gear from the opposite side in the radial direction of the slider gear with respect to a pair of engagement surfaces provided on the slider gear. It is preferable that the end of the engaging pin protruding through the pin mounting hole and projecting to the opposite side is engaged with the pair of engaging surfaces.

  According to the first aspect of the present invention, the relative movement of the engagement pin in the circumferential direction of the pin mounting hole is allowed while the relative movement in the penetration direction is prevented, and according to the second aspect. For example, by limiting the relative movement of the engagement pin in the penetrating direction of the pin mounting hole within a specific range, while maintaining friction and vibration generated between the control shaft and the slider gear, it is easy to escape. The engagement pin can be prevented from colliding with the inner peripheral surface of the support pipe.

  The variable valve mechanism 9 of the internal combustion engine 5 according to the present invention includes an input portion 21 and an output portion 31 that are arranged on the same support pipe 20x and are swingably supported. The input portion 21 is driven by the rotary cam 10. Then, the intermediate drive mechanism 20 that drives the valve 8 by the output unit 31 and the rotation phase difference variable mechanism 41 that varies the relative rotation phase difference g between the input unit 21 and the output unit 31 are provided.

  The rotation phase difference variable mechanism 41 slides in the longitudinal directions F and R within the support pipe 20x and a slider gear 44 that meshes with helical splines having different angles from each other between the input unit 21 and the output unit 31. The control shaft 48 and the base end 53a are attached to a pin attachment hole 54 penetrating the control shaft 48, and the distal end 53b penetrates the support pipe 20x from the control shaft 48 and protrudes to the outside. 53, a pair of engagement surfaces 57a and 57b provided in the slider gear 44 extending in the circumferential directions O and C are restrained in the longitudinal directions F and R of the support pipe 20x and slide in the circumferential directions O and C. And a coupling mechanism 52 that can be engaged.

  The coupling mechanism 52 is formed in both of an inner circumferential groove 55 a that is annularly recessed along the inner peripheral surface of the pin mounting hole 54 and an outer circumferential groove 55 b that is annularly recessed along the outer peripheral surface of the engaging pin 53. The relative movement in the penetrating directions V and W while allowing the relative movement of the pin mounting hole 54 of the engagement pin 53 in the circumferential directions P and Q, with the engagement of the C ring 55c, between 0.25 and 0. Collision preventing means 55 is provided for restricting the end of the engagement pin 53 from colliding with the inner peripheral surface of the support pipe 20x by limiting the distance within a range of 35 mm.

  The variable valve mechanism 9 shown in FIGS. 1 to 8 of the present embodiment is a mechanism for continuously changing the valve opening / closing amount in accordance with the operating state of the internal combustion engine. It is attached to the valve 8. Specifically, there is one variable valve mechanism 9 for each cylinder 6, and each variable valve mechanism 9 is installed in the cylinder head 7 for each cylinder 6, and the intake valve described above. Two 8 are pressed simultaneously.

  The variable valve mechanism 9 includes a rotary cam 10 that is rotationally driven as the internal combustion engine 5 is operated, a rocker arm 15 that swings and opens and closes the valve 8 when power is transmitted, and the rotary cam 10 and the rocker arm 15. An intermediate drive mechanism 20 that adjusts the amount of opening and closing of the valve 8 by transmitting the power from the rotary cam 10 to the rocker arm 15 in a variable amount is interposed therebetween.

  The rotating cam 10 is formed on a camshaft 10 x that is rotatably installed above the cylinder head 7, 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. A cam surface 10 s for pressing the mediating drive mechanism 20 is formed on the outer peripheral surface of the rotating cam 10.

  There are two rocker arms 15 for each variable valve mechanism 9, and one rocker arm 15 is installed for each valve 8. Each rocker arm 15 has a base end 15 a supported by a lash adjuster 17 so as to be swingable, and a tip end 15 b abutting against a stem end 8 e of the valve 8. A roller 16 that is pressed by the mediating drive mechanism 20 is pivotally attached to the intermediate portion of the rocker arm 15.

  The intermediary drive mechanism 20 includes an input unit 21 and an output unit 31 that are arranged on the same support pipe 20 x so as to be swingable. When the input unit 21 is driven by the rotary cam 10, the output unit 31 causes the valve 8. A rotation phase difference variable mechanism 41 that varies the relative rotation phase difference g between the input unit 21 and the output unit 31 is provided in the mechanism. In the following, one of the longitudinal directions of the support pipe 20x is defined as the front F and the other is defined as the rear R, and the mediating drive mechanism 20 presses the rocker arm 15 in the circumferential direction of the support pipe 20x to The direction on the side that opens is the opening direction O, and the direction on the opposite side is the closing direction C.

  The support pipe 20x is a single pipe shared by the plurality of variable valve mechanisms 9, and is turned around the plurality of standing wall portions 7v arranged in parallel at intervals in the front-rear directions F and R on the upper portion of the cylinder head 7. It is fixed immovable. And between two of the plurality of standing wall portions 7v, the input portion 21 and the output portion 31 of one intermediary drive mechanism 20 are supported side by side with their end faces aligned. The input portion 21 and the output portion 31 are prevented from moving in the front-rear directions F and R by having both ends of the arrangement in contact with the standing wall portions 7v on both sides.

  The input part 21 is disposed at a substantially center between the standing wall parts 7v. The input portion 21 includes a cylindrical base circle portion 22 serving as a basic portion, an input arm 24 that supports an input roller 25 that contacts the rotating cam 10, and a return arm 27 to which a return spring 28 is attached. A shaft hole through which the support pipe 20x and the rotation phase difference variable mechanism 41 are inserted is formed at the center of the base circle portion 22. Two input arms 24 are formed so as to protrude in parallel to the outer peripheral surface of the base circle portion 22, and the above-described input roller 25 is axially attached via a shaft 26 between the tips of both input arms 24. Yes. The return arm 27 is formed on the opposite side in the radial direction of the input portion 21 with respect to both the input arms 24, and the return arm 27 is attached in the closing direction C between the return arm 27 and the external spring mounting portion 29. The above-described return spring 28 that attaches the input roller 25 to the cam surface 10s of the rotating cam 10 by being biased is attached. Since the input unit 21 always contacts the rotating cam 10 by the above-described mechanism, the basic position of the input unit 21 also changes when the relative rotation phase difference g with the output unit 31 changes. There is nothing. However, the basic position refers to a position on the most closing direction C side that is located while swinging in the opening and closing directions O and C, and the same applies to the output unit 31.

  The output unit 31 is arranged one by one on both sides in the front-rear direction F, R of the input unit 21. Each output portion 31 includes a base circle portion 32 serving as a basic portion and an output nose 34 having an output cam surface 34 s for pressing the rocker arm 15. A shaft hole for inserting the pipe 20x and the rotation phase difference variable mechanism 41 is formed. Moreover, the bearing part 33 provided with the center hole for inserting the support pipe 20x in each end surface on the opposite side to the input part 21 side of each output part 31 is provided. The output nose 34 of each output portion 31 is formed so as to protrude from the outer peripheral surface of the base circular portion 32, and the above-described output cam curved in a concave shape is formed on the outer peripheral surface on the opening direction O side from the top of the output nose 34. A surface 34s is formed.

  The rotation phase difference variable mechanism 41 includes a slider gear 44 that meshes with helical splines having different angles between the input portion 21 and the output portion 31, and a longitudinal direction F that is the length direction of the inside of the support pipe 20x. , R, and a connecting mechanism 52 that connects the slider gear 44 and the control shaft 48 to each other.

  The slider gear 44 is inserted between the support pipe 20 x and the input portion 21 and the output portion 31, and the input portion helical provided on the inner peripheral surface of the input portion 21 is disposed on the outer peripheral surface of the slider gear 44. An input helical spline 45 that meshes with the spline 42 and an output helical spline 46 that meshes with the output helical spline 43 provided on the inner peripheral surface of the output unit 31 are provided. The details of these helical splines are such that the input helical spline 45 and the input portion helical spline 42 meshing with the helical spline 45 rotate in the closing direction C from the front F toward the rear R (in the figure, a right-handed spiral). The output helical spline 46 and the output portion helical spline 43 that mesh with the output helical spline 46 are formed in a spiral shape (left-handed spiral shape in the drawing) that turns in the opening direction O as it advances from the front F to the rear R. . The shape of the slider gear 44 is substantially cylindrical, the inner peripheral surface is in sliding contact with the support pipe 20x, and the input helical spline 45 and the output helical spline 46 are arranged in the front-rear direction F, on the outer peripheral surface. Formed at an interval to R. And between these both helical splines 45 and 46, the small diameter part 47 in which the diameter became small compared with the other part is formed.

  Like the support pipe 20x, the control shaft 48 is a single shaft shared by the plurality of variable valve mechanisms 9, and at one end thereof, the lift amount that drives the control shaft 48 in the front-rear directions F and R is variable. An actuator 49 is connected.

  The coupling mechanism 52 has a slit hole 57 provided in the slider gear 44 extending in the opening and closing directions O and C, a long hole 58 provided in the support pipe 20x extending in the front and rear directions F and R, and a base end 53a having a control shaft 48. An engagement pin 53 that is attached to a pin attachment hole 54 penetrating into the slit, and has a distal end 53b that protrudes from the control shaft 48 and passes through the elongated hole 58 and engages with the slit hole 57, and the pin attachment of the engagement pin 53 The base end 53a of the engagement pin 53 collides with the inner peripheral surface of the support pipe 20x by preventing the relative movement in the penetration directions V and W while allowing the relative movement in the circumferential directions P and Q of the hole 54. And a collision preventing means 55 for preventing the above. Further, a pin insertion passage 59 is formed around the coupling mechanism 52 so that the engagement pin 53 can be inserted into the intermediate drive mechanism 20 when the engagement pin 53 is attached to the pin attachment hole 54. .

  The slit hole 57 is provided in the small-diameter portion 47 of the slider gear 44 in an elongated shape in an arc shape in the circumferential direction, and a pair of engagements that are in sliding contact with the outer peripheral surface of the engagement pin 53 are formed on both inner side surfaces of the slit hole 57. The mating surfaces 57a and 57b are provided.

  One engagement pin 53 protrudes from the control shaft 48 for each intermediary drive mechanism 20, and each engagement pin 53 is spaced between the base end 53a and the inner peripheral surface of the support pipe 20x. It is attached with the A chamfer 53e is formed on the outer periphery of the tip 53b of the engagement pin 53 to press and spread a C ring 55c, which will be described later, outward when the pin 53 is attached to the pin attachment hole 54.

  The collision preventing means 55 includes an inner peripheral groove 55a that is annularly recessed along the inner peripheral surface of the pin mounting hole 54, an outer peripheral groove 55b that is annularly recessed along the outer peripheral surface of the engagement pin 53, A substantially annular C-ring 55c that engages with both the grooves is configured. This collision prevention means 55 does not completely prevent the relative movement of the engagement pin 53 in the through-directions V and W of the pin mounting hole 54, and the relative movement between the outer peripheral groove 55b and the C ring 55c A clearance 55p is provided for allowing movement within a range of about 0.2 mm.

  The C ring 55 c is a C-shaped substantially annular member with a part of the ring interrupted so as to be expandable outward, and the inner diameter thereof is smaller than the outer diameter of the engagement pin 53. Further, the inner circumferential groove 55a has an inner diameter at the bottom of the groove that is slightly larger than the outer diameter of the C ring 55c. More specifically, when the engagement pin 53 is inserted into the ring of the C ring 55c, the C ring 55c is expanded. The groove width is substantially equal to the width of the C-ring 55c. The outer peripheral groove 55b has an outer diameter of the groove bottom substantially equal to the inner diameter of the C-ring 55c. The groove width is slightly larger than the width of the C-ring 55c. It is larger by the amount allowed.

  The pin insertion passage 59 is a passage that can communicate from the outer peripheral surface of the input portion 21 to the inner peripheral surface of the support pipe 20 x, and is provided in the pin insertion hole 59 c provided in the input portion 21 and the slider gear 44. The pin insertion hole 59b and the pin insertion hole 59a penetrating the support pipe 20x are configured. Specifically, the pin insertion hole 59b of the slider gear 44 is formed on one end of the slit hole 57 and on the opposite side in the radial direction of the small diameter portion 47 with respect to the inner portion thereof, and the pin insertion hole 59a of the support pipe 20x is The support pipe 20x is formed on the opposite side of the radial direction of the support pipe 20x with respect to one end of the long hole 58 and the inner portion thereof.

A state of assembling the mediation drive mechanism 20 shown above will be described in the following procedures (1) to (5) with reference to FIGS. 5 and 6.
(1) First, the C ring 55 c is fitted into the inner peripheral groove 55 a in the pin mounting hole 54. This operation is performed by first pressing the C-ring 55c inward to fit the C-ring 55c in the vicinity of the opening of the pin mounting hole 54 while compressing the C-ring 55c, and then pushing it inward.
(2) Next, after the input portion 21 and the output portion 31 are extrapolated to the slider gear 44 at a predetermined angle, the slider gear 44 is disposed between two adjacent standing wall portions 7v. The support pipe 20x and the control shaft 48 are inserted into the standing wall 7v.
(3) Next, the control shaft 48, the support pipe 20x, the slider gear 44, and the input section so that the pin mounting hole 54 and the pin insertion holes 59a, 59b, 59c formed in each member are aligned. Adjust the position of 21.
(4) Next, as shown in FIGS. 5A and 5B, the pin insertion holes 59a, 59b, and 59c are arranged in a straight line so that the input portion 21 and the slider are moved from the outer peripheral surface of the input portion 21. The engagement pin 53 is inserted from the pin insertion passage 59 that passes through the gear 44 and the support pipe 20x to the inner peripheral surface of the support pipe 20x, and the engagement pin 53 is attached to the pin attachment hole 54. The tip 53 b of the engagement pin 53 that passes through the pin attachment hole 54 and protrudes to the opposite side is inserted into the slit hole 57. At this time, first, as shown in FIGS. 6A and 6B, the C-ring 55c is spread outward by the chamfer 53e of the tip 53b, and then as shown in FIGS. 6C and 6D. Then, the engaging pin 53 is inserted through the ring of the expanded C ring 55c. Finally, as shown in FIGS. 6E and 6F, the outer peripheral groove 55b is aligned with the C ring 55c. The C ring 55c is fitted in the outer peripheral groove 55b by contracting inward to return to its own shape.
(5) Finally, as shown in FIGS. 5C and 5D, by moving the support pipe 20x by one pin insertion hole 59a in the front-rear directions F and R, the pin insertion hole 59a is moved during operation. After the engagement pin 53 is moved to a position where it does not slide, the support pipe 20x is fixed to each standing wall 7v so as not to be relatively movable, and the control shaft 48 is connected to the lift amount variable actuator 49 so as not to be relatively movable.

  Next, when the variable valve mechanism 9 described above opens and closes the valve 8, (a) when the valve opening / closing amount is constant, (b) when the valve opening / closing amount increases, and (c) when the valve opening / closing amount decreases. This will be described in order in three categories.

(A) When the valve opening / closing amount is constant (when the rotation phase difference variable mechanism 41 is stationary)
When the opening / closing amount of the valve 8 is kept constant, there is no need to change the relative rotational phase difference g between the input unit 21 and the output unit 31, so that the control shaft 48 is moved in the front-rear direction F, R by the lift amount variable actuator 49. Will not be driven to. Therefore, the input unit 21 and the output unit 31 swing integrally with the slider gear 44 coupled by the meshing of the helical splines while keeping the relative rotation phase difference g fixed, and keep the opening / closing amount constant. The valve 8 is opened and closed as it is.

(A) When the valve opening / closing amount increases (when the rotation phase difference variable mechanism 41 is actually operated)
When the opening / closing amount of the valve 8 is increased, as shown in FIG. 7A, as the control shaft 48 is pressed and slid forward F by the lift amount variable actuator 49, the slider gear 44 also moves toward the front F side. The engaging surface 57a is pressed by the engaging pin 53 and slides forward F while swinging in the opening and closing directions O and C. As a result, the input unit 21 and the output unit 31 rotate in opposite directions due to the meshing of the helical splines, and the relative rotational phase difference g between the two increases. At this time, since the basic position of the input unit 21 is fixed by the return spring 28 and the rotary cam 10 as described above, the slider gear 44 rotates in the opening direction O with reference to the position of the input unit 21. When the output unit 31 is further rotated in the opening direction O with respect to the rotating slider gear 44, the output unit 31 is swung in the opening and closing directions O and C by the increase in the relative rotation phase difference g. While moving, the basic position is shifted in the opening direction O. Thereby, the drive amount of the rocker arm 15 by the rotating cam 10 increases, and the opening / closing amount of the valve 8 increases.

(C) When the valve opening / closing amount decreases (when the rotation phase difference variable mechanism 41 is actually operated)
When the opening / closing amount of the valve 8 is decreased, as shown in FIG. 7B, as the control shaft 48 is pushed rearward by the lift amount variable actuator 49 and slides, the slider gear 44 also moves toward the rear R side. The engaging surface 57b is pressed by the engaging pin 53 and slides backward R while swinging in the opening and closing directions O and C. As a result, the input unit 21 and the output unit 31 rotate in opposite directions due to the meshing of the helical splines, and the relative rotational phase difference g therebetween decreases. At this time, since the basic position of the input unit 21 is fixed as in the case of (A), the slider gear 44 rotates in the closing direction C with reference to the position of the input unit 21, and the rotation is further performed. The output unit 31 pivots in the closing direction C with respect to the moving slider gear 44, so that the output unit 31 swings in the opening and closing directions O and C by the decrease of the relative rotation phase difference g, but its basics. The position is shifted in the closing direction C. Thereby, the drive amount of the rocker arm 15 by the rotating cam 10 decreases, and the opening / closing amount of the valve 8 decreases.

  According to the present embodiment, since the collision preventing means 55 is provided, the pin mounting hole 54 is formed in the engaging pin 53 by sliding friction from the engaging surfaces 57a and 57b, for example, when the rotation phase difference variable mechanism 41 is actually operated. Even if a force in the penetration directions V and W is applied, the engagement pin 53 does not move greatly and jump out of the pin mounting hole 54 or collide with the inner peripheral surface of the support pipe 20x.

  Also at that time, according to the collision preventing means 55, the relative movement of the pin mounting hole 54 of the engagement pin 53 in the circumferential directions P and Q is allowed, so that the engagement pin 53 can be rotated. In addition to this, relative movement in the penetration directions V and W is also permitted by the clearance 55p within a specific range, so that the engagement pin 53 is within the range as shown in FIGS. 8 (a) and 8 (b). Next, it is translated along the pin mounting hole 54 or tilted (cocked) by moving both sides in the radial direction in opposite directions as shown in FIGS. 8 (c) and 8 (d). Is also possible. Therefore, during actual operation or the like, the friction pin or the vibration applied between the slider gear 44 and the control shaft 48 can be released by rotating the engagement pin 53 or changing the position or inclination. . Naturally, at this time, as shown in each drawing of FIG. 8, a gap is maintained between the base end 53 a of the engagement pin 53 and the support pipe 20 x, so that they do not collide with each other.

  Further, when assembled according to the procedure of this embodiment, the assembly of the collision preventing means 55 is simple.

  The present invention is not limited to the configuration of the above embodiment, and can be modified and embodied without departing from the spirit of the invention. For example, the interval between the engagement surfaces 57a and 57b is increased, A bush that is slidably in contact with the engagement surface may be extrapolated to the tip 53 b of the engagement pin 53.

It is a whole side view which shows the variable valve mechanism of the Example of this invention. It is a perspective view which shows the mediation drive mechanism of the Example, and its periphery. It is a disassembled perspective view which shows the mediation drive mechanism of the Example. (A) which shows the mediation drive mechanism of the Example, and its periphery is an upper surface sectional view, (b) is a front sectional view, (c) is the partial enlarged view, (d) is further the partial enlarged view. In the same Example, (a) (c) which shows a mode at the time of assembling a mediation drive mechanism is front sectional drawing, (b) (d) is side sectional drawing. In the same Example, (a) (c) (e) which shows a mode at the time of inserting an engagement pin in a pin attachment hole is front sectional drawing, (b) (d) (f) is top sectional drawing. In the embodiment, (a) is a front sectional view showing an intermediate drive mechanism when the valve opening / closing amount is increased, and (b) is a front sectional view showing a state of the intermediate driving mechanism when reducing the valve opening / closing amount. It is a front view which shows the mode of the engagement pin of the Example. (A) is a top sectional view, (b) is a front sectional view (c) is a partially enlarged view, and (d) is a partially enlarged view showing a state in actual operation. is there.

Explanation of symbols

DESCRIPTION OF SYMBOLS 5 Internal combustion engine 8 Valve 9 Variable valve mechanism 10 Rotating cam 20 Mediating drive mechanism 20x Support pipe 21 Input part 31 Output part 41 Turning phase difference variable mechanism 44 Slider gear 48 Control shaft 52 Connection mechanism 53 Engagement pin 53a Engagement pin Base end (one end)
53b Tip of engagement pin (other end)
54 pin mounting hole 55 anti-collision means 55a inner circumferential groove 55b outer circumferential groove 55c C ring (substantially annular engaging member)
57a engagement surface 57b engagement surface g relative rotation phase difference F front (length direction of support pipe)
R rear (length direction of support pipe)
O Opening direction (circumferential direction of support pipe)
C Closing direction (circumferential direction of support pipe)
V Pin mounting hole through direction W Pin mounting hole through direction P Pin mounting hole circumferential direction Q Pin mounting hole circumferential direction

Claims (3)

A mediating drive mechanism that includes an input unit and an output unit that are swingably supported side by side on the same support pipe, and that drives the valve by the output unit when the input unit is driven by a rotating cam; and the input In a variable valve mechanism for an internal combustion engine, including a rotation phase difference variable mechanism that varies a relative rotation phase difference between a part and the output unit,
The rotating phase difference variable mechanism includes a slider gear that engages helical splines having different angles with each other between the input unit and the output unit, and a control shaft that slides in the length direction of the support pipe. One end is attached to a pin mounting hole penetrating the control shaft, and the other end is an engagement pin protruding from the control shaft through the support pipe and projecting to the outside. A pair of engaging surfaces extending in the direction includes a coupling mechanism that is constrained in the length direction of the support pipe and slidably engaged in the circumferential direction,
The coupling mechanism is annularly formed on both the inner circumferential groove that is annularly recessed along the inner peripheral surface of the pin mounting hole and the outer peripheral groove that is annularly recessed along the outer peripheral surface of the engagement pin. One end of the engaging pin is formed by engaging a substantially annular engaging member to prevent relative movement in the circumferential direction of the pin mounting hole of the engaging pin while preventing relative movement in the penetrating direction. A variable valve mechanism for an internal combustion engine, comprising: a collision preventing means for preventing the engine from colliding with the inner peripheral surface of the support pipe. A mediating drive mechanism that includes an input unit and an output unit that are swingably supported side by side on the same support pipe, and that drives the valve by the output unit when the input unit is driven by a rotating cam; and the input In a variable valve mechanism for an internal combustion engine, including a rotation phase difference variable mechanism that varies a relative rotation phase difference between a part and the output unit,
The rotating phase difference variable mechanism includes a slider gear that engages helical splines having different angles with each other between the input unit and the output unit, and a control shaft that slides in the length direction of the support pipe. One end is attached to a pin mounting hole penetrating the control shaft, and the other end is an engagement pin protruding from the control shaft through the support pipe and projecting to the outside. A pair of engaging surfaces extending in the direction includes a coupling mechanism that is constrained in the length direction of the support pipe and slidably engaged in the circumferential direction,
The coupling mechanism restricts relative movement of the engagement pin in the penetrating direction of the pin mounting hole within a range of 0.1 to 0.4 mm, and one end of the engagement pin is an inner peripheral surface of the support pipe. A variable valve mechanism for an internal combustion engine, comprising a collision preventing means for preventing a collision with the engine. A mediating drive mechanism that includes an input unit and an output unit that are swingably supported side by side on the same support pipe, and that drives the valve by the output unit when the input unit is driven by a rotating cam; and the input In a method for assembling a variable valve mechanism for an internal combustion engine, comprising a rotation phase difference variable mechanism that varies a relative rotation phase difference between a part and the output unit,
The rotating phase difference variable mechanism is assembled by an inner peripheral groove that is annularly recessed along an inner peripheral surface of a pin mounting hole that is provided in a control shaft that slides in the length direction of the support pipe. Engaging an annular or substantially annular engagement member;
Inserting the support pipe and the control shaft into a slider gear that engages helical splines having different angles with each other between the input unit and the output unit;
The engagement member is expanded by penetrating through the support pipe, engaging the slider gear with the control shaft in the length direction of the support pipe and slidably engaging in the circumferential direction. And inserting the pin into the pin mounting hole and engaging the engaging member with an outer peripheral groove that is annularly recessed along the outer peripheral surface of the engaging pin. A method for assembling a variable valve mechanism for an internal combustion engine.

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