JP2011220175A - Variable valve device of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a variable valve device of an internal combustion engine, capable of reducing the dispersion of the contact position of a side surface vertical wall of a guide groove with a pin.SOLUTION: The variable valve device of the internal combustion engine includes: an actuator capable of thrusting the pin 44b; a cylindrical part 18a that rotates with a camshaft; a guide vertical wall 78 that is formed on an outer peripheral surface of the cylindrical part 18a, and guides the relative displacement of the pin 44b thrust by the actuator and the cylindrical part 18a; a switching mechanism that switches the valve opening characteristics of a valve by the relative displacement; and a guiding means 84 that induces the pin 44b thrust by the actuator to the guide vertical wall 78 before the relative displacement starts.

Description

  The present invention relates to a variable valve operating apparatus for an internal combustion engine.

  Conventionally, for example, in Patent Document 1, a cam carrier provided with two types of cams is provided for each cylinder, and the cam carrier is moved in the axial direction with respect to a cam shaft that is rotationally driven. A valve mechanism for an internal combustion engine that switches a drive cam is disclosed. More specifically, in this conventional valve operating mechanism, guide grooves formed in a spiral shape are provided at both ends of the outer peripheral surface of each cam carrier. In addition, an electric actuator that drives a pin inserted into and removed from the guide groove is provided for each guide groove.

  According to the conventional valve mechanism described above, when the pin is inserted into the guide groove, the pin comes into contact with the longitudinal side wall of the guide groove formed in a spiral as the cam shaft and the cam carrier rotate. , Guided along the longitudinal side wall of the spiral. As a result, the cam carrier can be moved (displaced) in the axial direction with respect to the cam shaft. Thereby, the valve drive cam of each cylinder can be switched to change the valve lift amount.

Japan Special Table 2006-520869

  Incidentally, since the pin insertion position varies, the groove width of the guide groove described above is designed to be slightly larger than the pin diameter in consideration of the variation. Further, the positional relationship between the pin and the guide groove is designed so that the pin is securely inserted. However, since the variation of the insertion position itself occurs, in the conventional valve operating mechanism, the variation occurs in the position where the side wall vertical wall of the spirally formed guide groove contacts the inserted pin. Depending on the contact position, a large force (for example, a large force that causes galling between the members) acts between the members connected to the pins and the guide grooves. Therefore, it is desired to improve the reliability of the valve operating mechanism by reducing the variation of the contact position.

  The present invention has been made to solve the above-described problems, and provides a variable valve operating apparatus for an internal combustion engine that can reduce variations in the contact position between the vertical side wall of the guide groove and the pin. Objective.

In order to achieve the above object, a first invention is a variable valve operating apparatus for an internal combustion engine,
An actuator that can project a pin;
A cylindrical portion that rotates with the camshaft;
A guide vertical wall that is formed on the outer peripheral surface of the cylindrical portion and guides relative displacement between the pin protruding from the actuator and the cylindrical portion;
A switching mechanism for switching the valve opening characteristics by the relative displacement;
Guiding means for guiding the pin protruding from the actuator to the guide vertical wall before the start of the relative displacement is provided.

The second invention is the first invention, wherein
The guiding means includes
A pin contact surface that is formed on the outer peripheral surface and contacts the pin protruding to the actuator before the start of the relative displacement;
The pin contact surface is an inclined surface inclined obliquely forward toward the guide vertical wall when viewed from the protruding direction of the pin.

The third invention is the first invention, wherein
The guiding means includes
A pin contact surface that is formed on the outer peripheral surface and contacts the pin protruding to the actuator before the start of the relative displacement;
A small protrusion provided at the tip of the pin and smaller than the diameter of the pin;
An introduction groove that is provided on the pin contact surface and guides the inserted small protrusion along the groove;
Is further provided.

Moreover, 4th invention is set in 3rd invention,
The outer peripheral surface includes a concave guide groove having the contact surface having the introduction groove as a bottom surface and the guide vertical wall as one side surface,
The small protrusion is a hemispherical portion that is coaxial with the pin and whose diameter is smaller than the groove width of the introduction groove,
The distance between the axial center of the pin and the intermediate point of the groove width of the guide groove is less than half of the difference between the groove width of the guide groove and the diameter of the pin.

According to a fifth invention, in any one of the first to fourth inventions,
The guide vertical wall further includes a vertical wall that guides the pin in the direction opposite to the direction of the displacement after guiding the relative displacement.

  According to 1st invention, the pin protruded by the actuator can be guide | induced to a guide vertical wall before the relative displacement start of a pin and a cylindrical part. For this reason, according to this invention, the dispersion | variation in the movement path | route of a pin can be reduced and the dispersion | variation in the contact position of a pin and a guide vertical wall can be reduced. Therefore, the reliability of the variable valve operating device can be improved.

  According to the second aspect of the present invention, the pin contact surface inclined obliquely forward toward the guide vertical wall as viewed from the protruding direction of the pin is provided. Due to the inclination of the pin contact surface, the abutting pin can be smoothly guided toward the guide vertical wall as the camshaft rotates. By causing the pin to follow the guide vertical wall before the relative displacement between the pin and the cylindrical portion starts, collision between the pin and the guide vertical wall after the start of displacement can be suppressed. For this reason, according to this invention, the impact added between the member connected with a pin or a guide vertical wall can be reduced, and the galling between members can be prevented.

  According to the third aspect, the introduction groove for guiding the small protrusion provided at the tip of the pin along the groove is provided on the pin contact surface. The pin can be guided to the guide vertical wall by guiding the small protrusion along the introduction groove. By causing the pin to follow the guide vertical wall before the relative displacement between the pin and the cylindrical portion starts, collision between the pin and the guide vertical wall after the start of displacement can be suppressed. For this reason, according to this invention, the impact added between the member connected with a pin or a guide vertical wall can be reduced, and the galling between members can be prevented.

  According to the fourth aspect of the present invention, the tip of the pin is provided with a hemispherical portion having a diameter smaller than the width of the introduction groove and concentric with the pin. Therefore, according to the present invention, when the hemispherical portion of the pin comes into contact with the vicinity of the introduction groove, the tip of the pin is hemispherical so that it is automatically aligned and automatically placed in the introduction groove. Therefore, the pin can be reliably inserted into the guide groove along the introduction groove.

  Further, according to the fourth invention, the distance between the pin shaft center and the midpoint of the groove width of the guide groove is set to be not more than half of the difference between the groove width of the guide groove and the diameter of the pin. For this reason, according to the present invention, it is not necessary to finely adjust the initial position at the time of assembling the pin so that the insertion position of the pin is at the center of the guide groove width, and the assembling property can be greatly improved.

  According to the fifth invention, after guiding the relative displacement between the pin protruding from the actuator and the cylindrical portion, the vertical wall is provided to guide the pin in the direction opposite to the direction of the displacement. Therefore, according to the present invention, even if the relative displacement amount between the pin and the cylindrical portion due to the guide vertical wall is set large in advance in consideration of the displacement amount decrease due to pin wear, The pin can be guided in the opposite direction to obtain an appropriate amount of displacement.

1 is a perspective view showing a variable valve operating apparatus for an internal combustion engine in Embodiment 1 of the present invention. FIG. 2 is a cross-sectional view of a plane including the axis of the rocker shaft and the axis of the switching pin shown in FIG. It is the figure which looked at the variable valve apparatus 10 in Embodiment 1 of this invention from the axial direction of the camshaft 18 (and rocker shaft 16). It is an expanded view of the guide rail 52 provided in the outer peripheral surface of the cylindrical part 18a in Embodiment 1 of this invention. It is sectional drawing of the radial direction of the guide rail 52 in each position of AD of FIG. It is the figure which looked at the variable valve apparatus 10 in Embodiment 2 of this invention from the axial direction of the cam shaft 18 (and rocker shaft 16). It is an expanded view of the guide rail 52 provided in the outer peripheral surface of the cylindrical part 18a in Embodiment 2 of this invention. It is a figure for demonstrating the detail of the small projection part 86 and the introduction groove | channel 90 in Embodiment 2 of this invention. It is sectional drawing of the radial direction of the guide rail 52 in each position of AI of FIG. It is an expanded view of the guide rail 52 provided in the outer peripheral surface of the cylindrical part 18a in Embodiment 3 of this invention. It is a figure for demonstrating the modification of the side surface vertical wall 78 in the end straight groove part 64 of Embodiment 3 of this invention. It is an expanded view of the conventional guide rail 66 which is the comparison object of the guide rail 52 in Embodiment 1 of this invention. It is sectional drawing of the radial direction of the guide rail 66 in each position of AD of FIG. It is a figure for demonstrating the state of the 1st slide arm 44 when the slide arm pin 44b collides with the side surface vertical wall. FIG. 15 is an enlarged view around the sliding surface 72 between the first slide arm 44 and the rocker shaft 16 in FIG. 14. It is a figure for demonstrating the displacement position of the 1st slide arm 44 before and behind pin abrasion. It is an expanded view of the guide rail 94 which is the comparison object of the guide rail 52 in Embodiment 3 of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, the same code | symbol is attached | subjected to the element which is common in each figure, and the overlapping description is abbreviate | omitted.

Embodiment 1 FIG.
[Overall configuration of variable valve system]
(Configuration of variable valve operating device)
A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a perspective view showing a variable valve gear 10 for an internal combustion engine 1 according to Embodiment 1 of the present invention. In FIG. 1, the camshaft 18 described later is not shown. In FIG. 1, illustrations other than some cylinders (# 1 and # 2) are omitted, but the internal combustion engine 1 of the present embodiment has four cylinders (# 1 to # 4) as an example. Assume that it is an in-line four-cylinder engine. As an example, each cylinder of the internal combustion engine 1 is provided with two intake valves and two exhaust valves. The variable valve gear 10 functions as a device for driving an intake valve or an exhaust valve disposed in each cylinder.

  As shown in FIG. 1, each cylinder of the internal combustion engine 1 is provided with a first rocker arm 12 and a second rocker arm 14 adjacent to each other. The rocker arms 12 and 14 of each cylinder are supported by a single rocker shaft 16 so as to be rotatable (oscillated).

  FIG. 2 is a cross-sectional view taken along a plane including the axis of the rocker shaft 16 shown in FIG. 1 and the axis of a switching pin 38 to be described later, except for the camshaft 18. 2A shows the variable valve apparatus 10 in a connected state, which will be described later, and FIG. 2B shows the variable valve apparatus 10 in an unconnected state, which will be described later.

  The camshaft 18 is connected to a crankshaft (not shown) by a timing chain, a timing belt, or a gear, and is configured to rotate at a half speed of the crankshaft. As shown in FIG. 2, the camshaft 18 is formed with one main cam 20 and one sub cam 22 per cylinder. The rocker shaft 16 is arranged in parallel with the camshaft 18.

  The main cam 20 is configured as a cam (lift cam) having an arc-shaped base circle portion coaxial with the camshaft 18 and a nose portion formed so as to bulge a part of the base circle radially outward. It is assumed that Moreover, in this embodiment, the subcam 22 shall be comprised as a cam (zero lift cam) which has only a base circle part.

  As shown in FIGS. 1 and 2, a first roller 24 is rotatably attached to the first rocker arm 12 at a position where it can contact the main cam 20. The first rocker arm 12 is urged by a spring (not shown) attached to the rocker shaft 16 so that the first roller 24 is always in contact with the main cam 20. The first rocker arm 12 configured as described above swings about the rocker shaft 16 as a fulcrum by the cooperation of the acting force of the main cam 20 and the biasing force of the spring.

  A second roller 26 is rotatably attached to the second rocker arm 14 at a position where it can contact the sub cam 22. Further, at the end of the second rocker arm 14 on the rocker shaft 16 side, the rocker shaft 16 is supported by a cam carrier 27 (or a cylinder head or the like) that is a stationary member of the internal combustion engine 1 via a lash adjuster (not shown). It is assumed that The second roller 26 provided on the second rocker arm 14 is urged toward the sub cam 22 by receiving a pushing force from the lash adjuster.

  Further, an abutting portion 14 a that abuts against the two valves 28 is provided at the end of the second rocker arm 14 opposite to the rocker shaft 16. That is, the second rocker arm 14 is shared by these two valves 28, and more specifically, is disposed so as to be positioned between the two valves 28 provided in the same cylinder. . Further, the valve 28 is urged in the valve closing direction by a valve spring 30 shown in FIG.

(Configuration of switching mechanism)
The variable valve operating apparatus 10 includes a connected state in which the first rocker arm 12 and the second rocker arm 14 are connected (see FIG. 2A) and an unconnected state in which the connection is released (see FIG. 2B). And a switching mechanism 32 for switching between. By providing such a switching mechanism 32, a state in which the acting force of the main cam 20 is transmitted to the second rocker arm 14 via the first rocker arm 12 (the above-described connected state), and the acting force are transmitted to the second rocker. The valve opening characteristic of the valve 28 can be switched by switching the state (not connected state) that is not transmitted to the arm 14.

  The configuration of the switching mechanism 32 will be described. As shown in FIG. 2, a first pin hole 34 a concentric with the first roller 24 is formed inside the support shaft 34 of the first roller 24, and inside the support shaft 36 of the second roller 26. A second pin hole 36a concentric with the second roller 26 is formed.

  The centers of the pin holes 34a and 36a are arranged at the same radius with the rocker shaft 16 being the center of rotation of the rocker arms 12 and 14 as the center. When the first roller 24 is in contact with the base circle of the main cam 20 and the second roller 26 is in contact with the base circle of the sub cam 22, the position of the first pin hole 34a and the second pin The position of the hole 36a matches.

  Further, a cylindrical switching pin 38 is movably disposed in the pin holes 34a and 36a. The first pin hole 34a is closed at the end opposite to the second rocker arm 14 and is opened at the end on the second rocker arm 14 side. A return spring 40 that urges the switching pin 38 toward the second rocker arm 14 (hereinafter referred to as “the advancement direction of the switching pin”) is disposed inside the first pin hole 34a. More specifically, the return spring 40 is configured to constantly urge the switching pin 38 toward the second rocker arm 14 in the mounted state.

  The second pin hole 36a is a through hole, and a cylindrical piston 42 is movably inserted therein. Further, in the # 1 cylinder, a first slide arm 44 having an arm portion 44a that contacts the piston 42 is disposed on the side surface of the second rocker arm 14 opposite to the first rocker arm 12. The first slide arm 44 is attached to the rocker shaft 16.

  On the other hand, in the # 2 cylinder, on the side surface of the second rocker arm 14 opposite to the first rocker arm 12, a second slide arm 46 having an arm portion 46a that contacts the piston 42 is disposed. The second slide arm 46 is attached to the rocker shaft 16.

  The difference between the first slide arm 44 and the second slide arm 46 is as follows. That is, a slide arm pin 44 b is provided at the tip of the arm portion 44 a of the first slide arm 44 so as to protrude toward the peripheral surface of the camshaft 18. In addition, a pressing surface 44 c that is pressed by an electromagnetic solenoid 54 described later is provided at the end of the first slide arm 44 opposite to the arm portion 44 a. It is assumed that the slide arm provided for the # 3 and 4 cylinders, not shown, is the same second slide arm 46 as the # 2 cylinder.

  As shown in FIG. 2, the rocker shaft 16 is formed in a hollow shape. A link shaft 48 is slidably inserted between the rocker shaft 16 and the rocker shaft 16. The link shaft 48 includes a first slide arm 44 disposed in the # 1 cylinder and a second slide arm 46 disposed in the # 2 to # 4 cylinders so that they can be simultaneously displaced in the axial direction of the rocker shaft 16. Shaft.

  In the link shaft 48, an annular groove 48a is formed corresponding to the arrangement site of the slide arms 44 and 46 of each cylinder. Further, a through hole (not shown) is formed on the peripheral surface of the rocker shaft 16 corresponding to each annular groove 48a.

  Further, the link shaft 48 and the rocker shaft 16 into which the link shaft 48 is inserted penetrate through the slide arms 44 and 46. The slide arms 44 and 46 are formed with press-fit pin holes for receiving the press-fit pins. Each press-fit pin passes through the slide arms 44 and 46 through the press-fit pin hole, and then engages with each annular groove 48a.

  The width of the annular groove 48a is set to be equal to the diameter of the press-fit pin. Further, each through hole of the rocker shaft 16 does not interfere with the press-fit pin and prevent the rotation of the first slide arm 44 when the first slide arm 44 rotates in accordance with the operation of an electromagnetic solenoid 54 described later. Thus, it is formed in a size with a margin. Furthermore, each through-hole has a long hole shape so as not to interfere with the press-fit pin and prevent the movement of the link shaft 48 when the link shaft 48 moves in the axial direction in accordance with the operation of the electromagnetic solenoid 54. Is formed.

  By adopting the above-described configuration, the first slide arm 44 is connected to the link shaft 48 in a manner that allows rotation and restrains axial movement. Similarly, the second slide arm 46 is also connected to the link shaft 48 in a manner that is free to rotate and restrains movement in the axial direction.

  In addition, as shown in FIG. 2, in the camshaft 18, a cylindrical portion 18 a formed in a cylindrical shape is formed on the outer peripheral surface facing the slide arm pin 44 b provided on the arm portion 44 a of the first slide arm 44. Has been. A spiral guide rail 52 extending in the circumferential direction is formed on the outer peripheral surface of the cylindrical portion 18a. Specifically, the guide rail 52 is formed as a groove in which a linear groove portion is connected to a start end and a terminal end of the spiral groove portion. The groove width of the guide rail 52 is formed to be slightly larger than the outer diameter of the slide arm pin 44b.

  The switching mechanism 32 includes an electromagnetic solenoid 54 as an actuator that generates a driving force for inserting the slide arm pin 44 b into the guide rail 52. The electromagnetic solenoid 54 is duty-controlled based on a command from an ECU (Electronic Control Unit) 56. The ECU 56 is an electronic control unit for controlling the operating state of the internal combustion engine 1.

  The electromagnetic solenoid 54 includes a drive shaft 54a and is fixed to a stop member such as the cam carrier 27. Here, the drive shaft 54a is provided at a position where the slide arm pin 44b faces the guide rail 52 and the pressing surface 44c can be pressed.

  Further, the direction of the spiral in the guide rail 52 is such that the first slide arm 44 and the first slide arm 44 when the camshaft 18 rotates in a certain rotational direction with the slide arm pin 44b inserted therein. 2 and the second slide arm 46 driven by the link shaft 48 are set to be displaced leftward in FIG. More specifically, the left direction in FIG. 2 means that each of the first slide arm 44 and the second slide arm 46 retracts the switching pin 38 against the urging force of the return spring 40 (the switching pin described above). And the first slide arm 44 and the second slide arm 46 come closer to the rocker arms 12 and 14.

  Here, the position of the first slide arm 44 in FIG. 2A, that is, the switching pin 38 is inserted into both the first pin hole 34a and the second pin hole 36a by the urging force of the return spring 40. The position of the first slide arm 44 at the time is referred to as “displacement end Pmax1”. When the first slide arm 44 is positioned at the displacement end Pmax1, the first rocker arm 12 and the second rocker arm 14 are connected to each other.

  The position of the first slide arm 44 in FIG. 2B, that is, the switching pin 38 receives a force utilizing the rotational force of the camshaft 18 from the slide arms 44, 46, whereby the switching pin 38 and the piston 42 are moved. The position of the first slide arm 44 when only inserted into the first pin hole 34a and the second pin hole 36a, respectively, is referred to as “displacement end Pmax2”. That is, when the first slide arm 44 is positioned at the displacement end Pmax2, the first rocker arm 12 and the second rocker arm 14 are in the non-connected state.

  FIG. 3 is a view of the variable valve apparatus 10 shown in FIG. 1 as viewed from the axial direction of the camshaft 18 (and the rocker shaft 16). In the present embodiment, the position of the start end 52a of the guide rail 52 in the axial direction of the camshaft 18 is set to coincide with the position of the slide arm pin 44b when the first slide arm 44 is positioned at the displacement end Pmax1. ing. The position of the terminal end 52b of the guide rail 52 in the axial direction of the camshaft 18 is set to coincide with the position of the slide arm pin 44b when the first slide arm 44 is positioned at the displacement end Pmax2. That is, in the present embodiment, the first slide arm 44 is configured to be displaceable between the displacement ends Pmax1 and Pmax2 within the range in which the slide arm pin 44b is guided by the guide rail 52.

  As shown in FIG. 3, the guide rail 52 includes a start straight groove portion 60 extending in the circumferential direction of the camshaft 18 as a predetermined section on the start end 52a side when the first slide arm 44 is positioned at the displacement end Pmax1. Is provided. The starting straight groove portion 60 is a shallow bottom portion where the guide rail 52 gradually becomes deeper as the camshaft 18 rotates. Further, the guide rail 52 is provided with an end straight groove 64 extending in the circumferential direction of the camshaft 18 as a predetermined section on the end 52b side after the first slide arm 44 reaches the displacement end Pmax2. The end straight groove portion 64 is a shallow bottom portion where the guide rail 52 gradually becomes shallow as the camshaft 18 rotates.

  Further, the first slide arm 44 is provided with a notch 44e formed in a concave shape by notching a part of the pressing surface 44c. When the driving force of the electromagnetic solenoid 54 is applied in the direction of the arrow α in FIG. 3, the pressing surface 44c is in contact with the driving shaft 54a while the first slide arm 44 is displaced from the displacement end Pmax1 to Pmax2. It is provided to be maintained. The notch portion 44e has the slide arm pin 44b taken out to the surface of the cylindrical portion 18a by the action of the end straight groove portion 64 which is the shallow bottom portion when the first slide arm 44 is positioned at the displacement end Pmax2. At a portion that can be engaged with the drive shaft 54a.

  The notch 44e is formed so as to engage with the drive shaft 54a in such a manner that the first slide arm 44 can be restricted from moving in the advancing direction of the switching pin 38.

  As described above, the switching pin 38, the return spring 40, the piston 42, the first slide arm 44, the second slide arm 46, the link shaft 48, the press-fit pin, the guide rail 52, and the electromagnetic whose current is controlled by the ECU 56. The switching mechanism 32 is configured by the solenoid 54.

[Basic operation of variable valve system]
(When the valve is operating)
When the valve is in an operating state, the drive of the electromagnetic solenoid 54 is turned off, so that the first slide arm 44 receives the urging force of the return spring 40 in a state of being separated from the camshaft 18 to the displacement end Pmax1. positioned. In this state, as shown to FIG. 2 (A), the 1st rocker arm 12 and the 2nd rocker arm 14 are connected via the switching pin 38 (the said connection state). As a result, the acting force of the main cam 20 is transmitted from the first rocker arm 12 to both valves 28 via the second rocker arm 14. Therefore, a normal lift operation of the valve 28 is performed according to the profile of the main cam 20.

(Valve stop control)
The valve stop operation is performed, for example, when a request for executing a predetermined valve stop operation such as a fuel cut request of the internal combustion engine 1 is detected by the ECU 56. First, energization of the electromagnetic solenoid 54 is started at a predetermined timing. As a result, the first slide arm 44 rotates around the rocker shaft 16 (link shaft 48) clockwise in FIG.

  When the first slide arm 44 rotates as described above, the slide arm pin 44 b engages with the guide rail 52. As a result, when the slide arm pin 44b is guided by the guide rail 52, the first slide arm 44 moves toward the displacement end Pmax2 using the rotational force of the camshaft 18. Then, the driving force of the first slide arm 44 from the guide rail 52 is transmitted to each second slide arm 46 via the press-fit pin and the link shaft 48, so that the link shaft 48 connected to the first slide arm 44. Furthermore, each second slide arm 46 connected to the link shaft 48 is displaced in conjunction with the first slide arm 44.

  When the first slide arm 44 reaches the displacement end Pmax2, the switching pin 38 is returned into the first pin hole 34a, so that the first rocker arm 12 and the second rocker arm 14 are disconnected. As a result, the acting force of the main cam 20 is not transmitted from the first rocker arm 12 to the second rocker arm 14. The sub cam 22 with which the second roller 26 abuts is a zero lift cam. For this reason, the force for driving the valve 28 is not applied to the second rocker arm 14 to which the acting force of the main cam 20 is not transmitted. As a result, the second rocker arm 14 is in a stationary state regardless of the rotation of the main cam 20, and the lift operation of the valve 28 is stopped at the valve closing position.

(Operation to keep the valve stopped)
Further, when the first slide arm 44 reaches the displacement end Pmax2, the first slide arm 44 rotates in a direction away from the camshaft 18 (guide rail 52) by the action of the end straight groove 64 which is a shallow bottom portion of the guide rail 52. Will be able to. Then, when the first slide arm 44 further rotates until the drive shaft 54a that is continuously driven by the electromagnetic solenoid 54 coincides with the notch 44e, the portion on the first slide arm 44 side that contacts the drive shaft 54a becomes. It switches from the pressing surface 44c to the notch 44e. As a result, the drive shaft 54a is engaged with the notch 44e, so that the first slide arm 44 is in a state in which the slide arm pin 44b is separated from the camshaft 18 and the biasing force of the return spring 40 by the drive shaft 54a. It will be held in a state of receiving. As a result, the state where the first rocker arm 12 and the second rocker arm 14 are disconnected, that is, the valve stop state is maintained. Further, according to the holding operation of the first slide arm 44 by the drive shaft 54a using such a notch portion 44e, friction caused by sliding between the rotating camshaft 18 and the slide arm pin 44b and the slide arm pin 44b The valve stop state can be maintained while avoiding the occurrence of wear.

(Valve return operation)
The valve return operation for returning from the valve stop state to the valve operation state is performed, for example, when a request for executing a predetermined valve return operation such as a return request from a fuel cut is detected by the ECU 56. Such a valve return operation is started by turning off the energization of the electromagnetic solenoid 54 at a predetermined timing. When the energization of the electromagnetic solenoid 54 is turned off, the engagement between the cutout portion 44e of the first slide arm 44 and the drive shaft 54a is released. As a result, the force that keeps the switching pin 38 in the first pin hole 34a against the urging force of the return spring 40 disappears. As a result, the switching pin 38 is moved in the advancing direction by the biasing force of the return spring 40, and the first rocker arm 12 and the second rocker arm 14 are connected via the switching pin 38, that is, the main cam. The operating force 20 returns to a state in which the valve 28 can be lifted. Further, as the switching pin 38 moves in the advancing direction by the urging force of the return spring 40, the first slide arm 44 (and the link shaft 48 and the second slide arm 46 interlocked therewith) are connected via the piston 42. Is returned from the displacement end Pmax2 to the displacement end Pmax1.

  According to the variable valve operating apparatus 10 of the present embodiment configured as described above, ON / OFF of energization to the electromagnetic solenoid 54, the rotational force of the camshaft 18, and the urging force of the return spring 40 are used. The axial position of the first slide arm 44 can be moved between the displacement ends Pmax1 and Pmax2. As a result, the operating state of the valve 28 can be switched between the valve operating state and the valve stopped state in the # 1 cylinder on which the first slide arm 44 is mounted. Further, the operating state of the valve 28 can be switched between the valve operating state and the valve stopped state in the remaining cylinders via the link shaft 48 and the second slide arm 46 interlocked with the first slide arm 44. Become. As described above, according to the variable valve operating apparatus 10, the operation state of the valves 28 disposed in all the cylinders of the internal combustion engine 1 can be switched using one electromagnetic solenoid 54. Moreover, according to the variable valve operating apparatus 10 having the above-described configuration, the valve stop state can be brought into a highly responsive state while the camshaft 18 makes one rotation by using the rotational force of the camshaft 18.

[Characteristic configuration of variable valve gear]
By the way, in the configuration of the variable valve apparatus 10 described above, the groove width of the guide rail 52 is designed to be slightly larger than the outer diameter of the slide arm pin 44b in consideration of variations in actual pin insertion positions. ing. At the time of valve stop control, the slide arm pin 44b needs to be surely inserted into the starting straight groove portion 60 of the guide rail 52. Therefore, in consideration of variations in the actual insertion position of the pin, the slide arm pin 44b and the guide rail 52 The positional relationship is designed. For example, the protruding direction of the slide arm pin 44 b is designed at the center position of the groove width of the guide rail 52.

  However, the following problems can occur. The problem will be described with reference to FIGS. FIG. 12 is a development view of a conventional guide rail (hereinafter referred to as guide rail 66) which is a comparison target of the guide rail 52 in the present embodiment. 13A to 13D are cross-sectional views in the radial direction of the guide rail 66 at positions A to D in FIG.

  A moving path of the slide arm pin 44b will be described. First, at the position A in FIG. 12, the slide arm pin 44b is inserted into the guide rail 66 (FIG. 13A). As shown in FIG. 13, the groove bottom surface of the guide rail 66 is formed in parallel with the axis of the camshaft 18. Therefore, the slide arm pin 44b inserted at the center position of the groove width of the guide rail 66 advances straight in the center of the groove of the guide rail 66 as the cam shaft 18 rotates (FIGS. 13B to 13C). ). Thereafter, the slide arm pin 44b collides with the vertical side wall of the spiral groove portion of the guide rail 66 at the position 68 in FIG. 12 (FIG. 13D).

  According to such a movement path, depending on the degree of collision between the slide arm pin 44b and the side surface vertical wall, a large force acts between the slide arm pin 44b, the side surface vertical wall and the members connected thereto.

  FIG. 14 is a view for explaining the state of the first slide arm 44 when the slide arm pin 44b collides with the side vertical wall. As shown in FIG. 14, when the slide arm pin 44 b collides with the vertical side wall, the slide arm pin 44 b is inclined 70 with respect to an angle perpendicular to the rocker shaft 16.

  FIG. 15 is an enlarged view around the sliding surface 72 between the first slide arm 44 and the rocker shaft 16 in FIG. As shown in FIG. 15, if the first slide arm 44 slides while the inclination 70 is generated, a galling 74 may occur between the rocker shaft 16 and the first slide arm 44. The occurrence of the galling 74 impairs smooth sliding. Further, there is a possibility that the first slide arm 44 may be broken because it cannot be locked and slid by the galling 74.

  Therefore, in the variable valve operating apparatus 10 according to the present embodiment, the slide arm pin 44b is guided to the side vertical wall by the start position of the spiral groove, and the collision between the slide arm pin 44b and the side vertical wall is suppressed. It was decided.

  A specific configuration of the guide rail 52 characteristic in the variable valve operating apparatus 10 of the present embodiment will be described with reference to FIGS. FIG. 4 is a development view of the guide rail 52 provided on the outer peripheral surface of the cylindrical portion 18a. As described above, the guide rail 52 is connected to the start straight groove portion 60 extending in the circumferential direction of the cylindrical portion 18a and the end of the start straight groove portion 60, and the slide arm is accompanied by the rotation of the camshaft 18 (rotation direction 76). A spiral groove 62 that guides the displacement from the displacement ends Pmax1 to Pmax2 of the pin 44b, and an end straight groove 64 that is connected to the end of the spiral groove 62 and extends in the circumferential direction of the cylindrical portion 18a.

  Here, the spiral groove 62 connected to the start straight groove 60 is formed so that the inclination with respect to the circumferential direction gradually increases from the spiral groove start position 77. The terminal end of the spiral groove 62 is formed so that the inclination with respect to the circumferential direction is gradually reduced, and is connected to the end straight groove 64.

  Further, since the groove width of the guide rail 52 is designed to be slightly larger than the diameter of the slide arm pin 44b, the side wall 78 of the side walls forming the groove of the guide rail 52 is the camshaft 18. The sliding arm pin 44b is moved along the slide arm pin 44b by the rotational force of the displacement end Pmax1 to Pmax2. On the other hand, the side vertical wall 80 facing the side vertical wall 78 does not act because it does not contact the slide arm pin 44b.

  The pin slide amount 82 represents the slide amount (displacement amount) of the pin from the displacement ends Pmax1 to Pmax2 in the axial direction of the camshaft 18. Further, the section of the spiral groove 62 is included in a section (base circle section) in which the base circle portion of the main cam 20 is in contact with the first roller 24.

  5A to 5D are cross-sectional views in the radial direction of the guide rail 52 at positions A to D in FIG. As shown in FIGS. 5A and 5B, the groove bottom surface 84 of the starting straight groove portion 60 is formed as an inclined surface that is deeply inclined from the side surface vertical wall 80 toward the side surface vertical wall 78. That is, the groove bottom surface 84 of the starting straight groove portion 60 is formed as an inclined surface inclined obliquely forward toward the side vertical wall 78 when viewed from the protruding direction of the slide arm pin 44b. In addition, as shown in FIGS. 5C and 5D, the inclination of the groove bottom surface 84 ends until the spiral groove start position 77 (FIG. 4) of the spiral groove portion 62. In the spiral groove portion 62, as shown in FIG. Is formed to be parallel to the axis of the camshaft 18.

  As shown in FIGS. 3 and 5, the depth of the groove bottom surface 84 is formed so as to gradually become deeper from the start straight groove portion 60 to the spiral groove portion 62, and gradually from the spiral groove portion 62 to the end straight groove portion 64. It is formed to be shallow. Here, the positional relationship between the groove bottom surface 84 and the slide arm pin 44 b is such that the slide arm pin 44 b protruding by receiving the driving force of the electromagnetic solenoid 54 abuts at least the groove bottom surface 84 of the starting linear groove portion 60. It has been established.

  The operation of the groove bottom surface 84 configured in this manner on the slide arm pin 44b will be described. First, the slide arm pin 44b is inserted into the central portion of the groove width of the starting straight groove portion 60, and the tip end of the pin comes into contact with the groove bottom surface 84 (FIG. 5A). The slide arm pin 44 b is guided by the driving force from the electromagnetic solenoid 54, the rotational force in the rotational direction 76 of the camshaft 18, and the inclination of the groove bottom surface 84, and moves along the groove bottom surface 84 toward the side vertical wall 78. (FIG. 5A). As a result, the slide arm pin 44b contacts the side wall 78 at the starting straight groove 60 (FIG. 5B). Thereafter, the slide arm pin 44b is guided along the spiral groove 62 along the side vertical wall 78 (FIGS. 5C and 5D).

  As described above, according to the configuration of the guide rail 52 of the present embodiment shown in FIGS. 4 to 5, the slide arm pin 44 b is moved to the vertical vertical wall by the inclination of the groove bottom surface 84 until the spiral groove start position 77. 78. Further, since the side vertical wall 78 is formed so that the inclination gradually increases from the spiral groove start position 77, the slide arm pin 44b is smoothly displaced from the displacement end Pmax1 to Pmax2 along the side vertical wall 78. Can be made. Therefore, it is possible to suppress the collision between the slide arm pin 44b and the side vertical wall 78 and to prevent the first slide arm 44 from being largely inclined. For this reason, according to the guide rail 52 of the present embodiment, it is possible to prevent the rocker shaft 16 and the first slide arm 44 from being galled. Further, since the slide arm pin 44b is prevented from being repelled by the collision and the pin can be prevented from being detached from the guide rail 52, a reliable valve stop can be realized.

  Furthermore, according to the configuration of the guide rail 52 of the present embodiment, the slide arm pin 44b can be guided so as to pass through the same path in the guide rail 52. Therefore, the movement variation of the first slide arm 44 at the time of valve stop and valve return can be reduced, and the reliability of the variable valve apparatus 10 can be improved.

  In addition, according to the configuration of the guide rail 52 of the present embodiment, the side vertical wall 80 does not come into contact with the slide arm pin 44b. Therefore, quenching, good dimensional accuracy, and a smooth wall surface are not required as processing specifications of the side vertical wall 80, and productivity can be improved and costs can be reduced.

  By the way, in the system of the first embodiment described above, the slide arm pin 44b of the first slide arm 44 is displaced by being guided by the side surface vertical wall 78, and the switching pin 38 is displaced. Then, the first rocker arm 12 and the second rocker arm 14 are switched between a connected state and a non-connected state via the switching pin 38 that is displaced, whereby the valve opening characteristics of the valve 28 are changed between the valve operating state and the valve operating state. It is designed to switch between the stopped state. However, the variable valve device according to the present invention is based on the relative displacement between the pin corresponding to the slide arm pin 44b guided by the guide vertical wall corresponding to the side vertical wall 78 and the cylindrical portion corresponding to the cylindrical portion 18a. The configuration is not limited to the above as long as the valve opening characteristics of the valve are switched.

  Specifically, the member that is displaced so as to switch the valve opening characteristics of the valve in accordance with the relative displacement between the pin and the cylindrical portion is not limited to the switching pin 38. Hereinafter, the first to fourth modifications will be described. These points are the same in the following embodiments.

  As a first modification, in a configuration in which a member having two types of cams (for example, a cam carrier having a cylindrical portion) is attached to a camshaft so as to be movable in the axial direction, the above-mentioned 2 A member provided with a kind of cam may be displaced in the axial direction of the camshaft so that the valve opening characteristic of the valve is switched by switching the cam contacting the switching mechanism.

  As a second modification, in the configuration in which the rocker arm is rotatably supported by the rocker shaft, the rocker arm is displaced in the axial direction of the rocker shaft on the rocker shaft in accordance with the movement of the pin. The operating state of the rocker arm may be switched by switching the cam that contacts the valve, and the valve opening characteristics of the valve may be switched.

  As a third modification, in a configuration including a rocker arm having a roller that comes into contact with a cam, the roller is displaced in the axial direction of the support shaft on the rocker arm in accordance with the displacement of the pin and the cylindrical portion. Thus, the operating state of the rocker arm may be switched by switching the cam that contacts the roller, and the valve opening characteristics of the valve may be switched.

  As a fourth modification, in the configuration in which the rocker arm is rotatably supported by the rocker shaft, the rocker shaft itself is displaced in the axial direction in accordance with the displacement of the pin and the cylindrical portion. The operating state of the rocker arm may be switched by switching the abutting cam.

  In the first embodiment described above, only the # 1 cylinder is provided with the cylindrical portion 18a including the guide rail 52, the electromagnetic solenoid 54, and the first slide arm 44. However, the cylinder provided with the elements corresponding to these in the present invention is not limited to this. For example, a plurality of cylinders may be used. This point is the same in the following embodiments.

  In the first embodiment described above, the slide arms 44 and 46 are rotatably supported by using the rocker shaft 16 for supporting the rocker arms 12 and 14. However, the member that supports the slide arms 44 and 46 in the present invention is not limited to the rocker shaft 16. For example, a shaft provided separately from the rocker shaft 16 may be used. This point is the same in the following embodiments.

  Moreover, in Embodiment 1 mentioned above, the example in which the sub cam 22 was comprised as a zero lift cam was demonstrated. However, the secondary cam in the present invention is not limited to the zero lift cam. For example, in the case of the configuration of the variable valve operating apparatus 10, it may be a secondary cam having a nose portion that makes it possible to obtain a lift smaller than that of the main cam 20. This point is the same in the following embodiments.

  In the first embodiment described above, an electromagnetic solenoid 54 is provided as an actuator that generates a driving force for inserting the slide arm pin 44b into the guide rail 52. Thereby, the valve opening characteristic of the valve | bulb 28 can be switched using an actuator excellent in responsiveness. However, the actuator in the present invention is not limited to this. For example, a hydraulically driven actuator may be used. This point is the same in the following embodiments.

  In the first embodiment described above, the slide arm pin 44b is the “pin” in the first invention, the electromagnetic solenoid 54 is the “actuator” in the first invention, and the cylindrical portion 18a is the first actuator. In the “cylindrical portion” of the invention, the side vertical wall 78 is the “guide vertical wall” in the first invention, the switching mechanism 32 is the “switching mechanism” in the first invention, and the groove bottom surface 84 in the starting linear groove portion 60. Corresponds to the “guidance means” in the first invention, and the groove bottom surface 84 corresponds to the “pin contact surface” in the second invention.

Embodiment 2. FIG.
[Basic Configuration in Embodiment 2]
Next, a second embodiment of the present invention will be described with reference to FIGS. The system of the present embodiment can be realized by adopting the configurations shown in FIGS. 6 to 9 described later in the configurations shown in FIGS. Therefore, the description of the configuration shown in FIGS. 1 to 2 is omitted or simplified.

[Characteristic Configuration in Embodiment 2]
In the first embodiment described above, the slide arm pin 44b is guided to the side vertical wall 78 by making the groove bottom surface 84 of the start straight groove portion 60 an inclined surface. On the other hand, in the configuration of the present embodiment, the action of the small protrusion provided on the slide arm pin 44b and the introduction groove provided on the groove bottom surface of the starting straight groove 60 is at least that of the first embodiment. It is characterized by achieving the same effect.

  A specific configuration in the present embodiment will be described with reference to FIGS. FIG. 6 is a view of the variable valve apparatus 10 shown in FIG. 1 as viewed from the axial direction of the camshaft 18 (and the rocker shaft 16). FIG. 7 is a development view of the guide rail 52 provided on the outer peripheral surface of the cylindrical portion 18a. 6 to 7 that are the same as those in FIGS. 3 to 4 are assigned the same reference numerals and descriptions thereof are omitted.

  As shown in FIG. 6, a hemispherical small protrusion 86 is further provided at the tip of the cylindrical slide arm pin 44b. As shown in FIG. 7, the groove bottom surface 88 of the guide rail 52 is formed with an introduction groove 90 for guiding the small protrusion 86 along the groove from before the start end of the start linear groove portion 60 to after the start end. The introduction groove 90 is formed in the circumferential direction of the cylindrical portion 18 a so as to guide the slide arm pin 44 b to the side vertical wall 78. The start end of the introduction groove 90 is formed in the vicinity where the slide arm pin 44b protruding by receiving the driving force of the electromagnetic solenoid 54 contacts the cylindrical portion 18a. The end of the introduction groove 90 is defined before the end of the start straight groove portion 60. Similarly, the groove bottom surface 91 of the guide rail 52 is formed with a lead-out groove 92 for guiding the small protrusion 86 along the groove before and after the end of the end straight groove 64.

  Further, as shown in FIG. 6, the depth of the groove bottom surface 88 is formed so as to gradually become deeper from the start straight groove portion 60 to the spiral groove portion 62. Further, the depth of the groove bottom surface 91 is formed so as to gradually become shallower from the spiral groove portion 62 to the end straight groove portion 64. Here, the positional relationship between the groove bottom surface 88 and the slide arm pin 44 b is such that the slide arm pin 44 b protruding by receiving the driving force of the electromagnetic solenoid 54 abuts at least the groove bottom surface 88 of the starting linear groove portion 60. It has been established.

  FIG. 8 is a view for explaining details of the small protrusion 86 and the introduction groove 90 of the present embodiment. The small protrusion 86 is a hemispherical protrusion having a diameter smaller than that of the cylindrical slide arm pin 44b. The small protrusion 86 is formed coaxially with the slide arm pin 44b. An introduction groove 90 is formed on the groove bottom surface 88 in the protruding direction of the small protrusion 86.

  The cross section of the introduction groove 90 is a circular concave shape, and the groove width c is formed larger than the diameter of the small protrusion 86. Specifically, in the cross section of the small protrusion 86 shown in FIG. 8, the circle center (radius R1) forming the outer shape of the small protrusion 86 is more distal than the circle center (radius R2) forming the outer shape of the introduction groove 90. Present on the side, and satisfies the relationship of radius R1 <radius R2.

  Further, the groove bottom surface 88 is formed in parallel with the axis of the camshaft 18. As shown in FIG. 8, a concave groove including a groove bottom surface 88, a side vertical wall 78, and a side vertical wall 80 is formed as the guide rail 52. The distance between the axis of the slide arm pin 44b and the intermediate point of the groove width of the guide rail 52 (the point where the distance from the side vertical wall 78 and the side vertical wall 80 is a) is the groove width of the guide rail 52. It is designed to be ½ or less of the value b obtained by subtracting the diameter of the slide arm pin 44b from the above.

  Further, the introduction groove 90 is offset toward the side vertical wall 78 with respect to the groove width center line of the guide rail 52. Further, the introduction groove 90 is offset so that the slide arm pin 44b and the side surface vertical wall 78 do not contact each other in consideration of dimensional variations. Further, the groove width of the introduction groove 90 is slightly smaller than variations in design tolerances (such as the fixing position of the rocker shaft 16 and the first slide arm 44, the position of the introduction groove 90, the position of the camshaft 18 and the rocker shaft 16). Designed to be large. Since the groove bottom surface 91 and the lead-out groove 92 have the same characteristics as the above-described groove bottom surface 88 and the introduction groove 90, the description thereof is omitted.

  The operation of the introduction groove 90 configured in this way to make the slide arm pin 44b will be described. FIG. 9 is a radial cross-sectional view of the guide rail 52 at each of the positions A to I in FIG. First, at the position A, the axis of the slide arm pin 44b is inserted in the vicinity of the center of the introduction groove 90 (FIG. 9A). At the position B, the hemispherical small protrusion 86 is aligned by the introduction groove 90 and automatically corrected to the center of the groove (FIG. 9B). At the position C, the small protrusion 86 inserted in the center of the groove is guided to the introduction groove 90 as it is and along the side vertical wall 78 of the starting straight groove 60 (FIG. 9C). Thereafter, the introduction groove 90 changes its end, but the slide arm pin 44b maintains the state along the side vertical wall 78 (FIG. 9D).

  After passing through the spiral groove start position 77, the slide arm pin 44b is guided along the side surface vertical wall 78 along the spiral groove portion 62 (FIGS. 9E and 9F). The slide arm pin 44b is displaced from the displacement end Pmax1 to Pmax2. Thereafter, the small protrusion 86 is inserted into the lead-out groove 92 up to a position G that is before the end of the end straight groove 64 (FIG. 9C). The small protrusion 86 is guided to the lead-out groove 92 at a certain interval even at positions H and I after the end of the end straight groove 64. (Fig. 9 (B), Fig. 9 (A))

  As described above, according to the configuration of the small protrusion 86 and the introduction groove 90 of the present embodiment shown in FIGS. 6 to 9, a part of the hemispherical small protrusion 86 is grounded to the introduction groove 90. The small protrusion 86 is automatically aligned and guided to the deepest part of the groove. Therefore, the slide arm pin 44 b can be guided to the side vertical wall 78 by the spiral groove start position 77. For this reason, according to the variable valve operating apparatus 10 of the present embodiment, the slide arm pin 44b is smoothly displaced from the displacement end Pmax1 to Pmax2 along the side surface vertical wall 78 in the same manner as in the first embodiment. 16 and the first slide arm 44 can be prevented from galling. In addition, the variation in the movement of the first slide arm 44 when the valve is stopped and when the valve is returned can be reduced, and the reliability of the variable valve apparatus 10 can be improved.

  Further, as described above, since the small protrusion 86 is automatically aligned and guided to the deepest groove portion of the introduction groove 90, the first slide is made so that the position of the slide arm pin 44b is at the center of the groove width. An operation of inserting a shim having a selected thickness at the end of the rocker shaft 16 to which the arm 44 is attached is not necessary, and the assemblability can be greatly improved.

  In addition, according to the configuration of the lead-out groove 92 of the present embodiment shown in FIGS. 6 to 9, the lead-out groove 92 can guide the slide arm pin 44b even when the side vertical wall 78 is worn. Therefore, the displacement position of the first slide arm becomes a constant place, and the valve stop can be surely executed.

  By the way, in the system of the second embodiment described above, both the introduction groove 90 and the lead-out groove 92 are used for the guide rail 52, but the present invention is not limited to this. Only one of them may be used. This point is the same in the following embodiments.

  In the second embodiment, the slide arm pin 44b is the “pin” in the first invention, the electromagnetic solenoid 54 is the “actuator” in the first invention, and the cylindrical portion 18a is the first actuator. In the “cylindrical portion” of the invention, the side vertical wall 78 is the “guide vertical wall” in the first invention, the switching mechanism 32 is the “switching mechanism” in the first invention, and the groove bottom surface 84 in the starting linear groove portion 60. Are the “guidance means” in the first invention, the groove bottom surface 88 is the “pin contact surface” in the third invention, and the small projection 86 is the “small projection” in the third invention and the In the fourth invention, the introduction groove 90 corresponds to the “introduction groove” in the third invention, and the guide rail 52 corresponds to the “guide groove” in the fourth invention.

Embodiment 3 FIG.
[Basic Configuration in Embodiment 3]
Next, a third embodiment of the present invention will be described with reference to FIGS. The system of the present embodiment can be realized by adopting the configuration of FIG. 10 or FIG. 11 described later in the configuration shown in FIGS. Therefore, the description of the configuration shown in FIGS. 1 to 2 is omitted or simplified.

  According to the first and second embodiments described above, the slide arm pin 44b can be displaced with high reliability from the displacement end Pmax1 to Pmax2 by the guide rail 52. At this time, the switching pin 38 is returned into the first pin hole 34a, and the slide arm pin 44b is in a state of receiving the urging force of the return spring 40. Thereafter, the cutout portion 44e of the first slide arm 44 is engaged with the drive shaft 54a (for example, a lock pin) by the action of the end straight groove portion 64 which is a shallow bottom portion. Thereby, the holding of the urging force can be changed from the slide arm pin 44b to the drive shaft 54a, and the valve stop state can be maintained.

  However, when the slide arm pin 44b is worn, the slide amount decreases, and therefore the slide arm pin 44b may not be displaced to the displacement end Pmax2. FIG. 16 is a diagram for explaining the displacement position of the first slide arm 44 before and after pin wear. A position P in FIG. 16 represents a displacement position (displacement end Pmax2) before pin wear, and a position Q represents a displacement position after pin wear. When the slide arm pin 44b is displaced to the position P (displacement end Pmax2), as described above, the notch portion 44e is engaged with the drive shaft 54a by the action of the end straight groove portion 64. On the other hand, when the pin is worn and displaced only to the position Q, the notch 44e cannot be displaced to the position engaged with the drive shaft 54a. As a result, there is a problem that the holding of the urging force cannot be changed from the slide arm pin 44b to the drive shaft 54a, and the valve stop state cannot be maintained.

  As one measure against this problem, the displacement of the slide arm pin 44b in the axial direction of the camshaft 18 (corresponding to the pin slide amount 82 shown in FIGS. 4 and 7) is displaced from the displacement end Pmax1 to Pmax2. It may be possible to design in advance larger than the amount. FIG. 17 is a development view of a guide rail (hereinafter referred to as a guide rail 94) which is a comparison target of the guide rail 52 in the present embodiment. The guide rail 94 is designed such that the pin slide amount is larger than the slide amount from the displacement ends Pmax1 to Pmax2.

  Certainly, according to such a configuration, even when the slide arm pin 44b is worn, the notch 44e can be displaced to a position where it is engaged with the drive shaft 54a. The holding of the urging force can be changed by the shaft 54a. However, the guide rail 94 to be compared is designed so that the pin slide amount is larger than the slide amount from the displacement ends Pmax1 to Pmax2, and therefore, the piston 42 moves between the rocker arms before the wear of the slide arm pin 44b. It will be pushed into the first pin hole 34a beyond (hereinafter simply referred to as over-pushing). In a state where the piston 42 is caught by the first rocker arm 12 due to over-pressing, the piston 42 and the first rocker arm 12 are repelled in the lift section 98 (FIG. 17) after displacement. Therefore, it cannot be said that the above measures are still sufficient as a solution for the problem.

[Characteristic Configuration in Embodiment 3]
Therefore, in the variable valve operating apparatus 10 of the present embodiment, the slide arm pin 44b is guided in the direction opposite to the over-pressing direction in the end linear groove portion 64 while being over-pressed in the spiral groove portion 62 of the guide rail 52. did.

  A specific configuration of the guide rail 52 that is characteristic in the variable valve operating apparatus 10 of the present embodiment will be described with reference to FIG. FIG. 10 is a development view of the guide rail 52 provided on the outer peripheral surface of the cylindrical portion 18a in the present embodiment. As described above, the guide rail 52 is provided with the starting straight groove portion 60 extending in the circumferential direction of the cylindrical portion 18a. A spiral groove 62 that guides the displacement from the displacement ends Pmax1 to Pmax3 of the slide arm pin 44b as the camshaft 18 rotates is connected to the end of the start straight groove 60. The displacement end Pmax3 is designed such that the pin slide amount 100 from Pmax1 is larger than Pmax2. The side vertical wall 78 acts to displace the slide arm pin 44b from the displacement end Pmax1 to Pmax3 along with the rotational force of the camshaft 18.

  As shown in FIG. 10, an end straight groove portion 64 extending in the circumferential direction of the cylindrical portion 18 a is connected to the end of the spiral groove portion 62. The end straight groove portion 64 is a shallow bottom portion where the guide rail 52 gradually becomes shallow as the camshaft 18 rotates. The section 102 of the end straight groove 64 is a base circle section. In the section 102, the notch 44e is configured to be engaged with at least the tip of the drive shaft 54a by the action of the shallow bottom. After the section 102 of the end straight groove portion 64, there is a lift section 98 (non-base circle section).

  In particular, the side vertical wall 78 includes a vertical wall 78a that is inclined in a direction opposite to the direction of displacement in the end straight groove portion 64 after the slide arm pin 44b is displaced to the displacement end Pmax3. The slide arm pin 44b is guided to the displacement end Pmax2 along the inclination of the vertical wall 78a by the urging force of the return spring 40. Preferably, the vertical wall 78a has a profile that guides the slide arm pin 44b to the displacement end Pmax2 by the start position R of the lift section 98 and gently engages the tip of the drive shaft 54a with the notch 44e. .

  As described above, according to the configuration of the guide rail 52 of the present embodiment shown in FIG. 10, even if the pin is worn by displacing the slide arm pin 44b to the displacement end Pmax3 in the base circle section. Since the notch 44e can be displaced to the position where it is engaged with the drive shaft 54a, the valve stop state can be reliably maintained.

  Further, according to the configuration of the vertical wall 78a of the present embodiment, the over-pushing can be eliminated by guiding the slide arm pin 44b to the displacement end Pmax2 until the start position R of the lift section 98 of the end straight groove portion 64. Can do. Therefore, the piston 42 and the first rocker arm 12 can be prevented from being repelled. Further, according to the configuration of the vertical wall 78a, the holding of the urging force can be changed from the slide arm pin 44b to the drive shaft 54a gently due to the inclination, which is effective from the viewpoint of reducing NV (Noise Vibration). Is.

  By the way, in Embodiment 3 mentioned above, although the vertical wall 78a is used as the side surface vertical wall 78 in the end straight groove part 64, the structure of this vertical wall is not limited to this. FIG. 11 is a view for explaining a modified example of the side vertical wall 78 in the end straight groove portion 64. As shown in FIG. 11, a section 104 longer than the section 102 (FIG. 10) may be provided, and a vertical wall 78b having a larger inclination than the vertical wall 78a may be used. According to the section 104, since the state of the displacement end Pmax3 can be maintained for a long time, the tip end of the drive shaft 54a can be sufficiently inserted into the notch 44e in consideration of the tip surface pressure of the drive shaft 54a. Thereafter, the vertical pushing wall 78b guides the slide arm pin 44b to the displacement end Pmax2 up to the start position R, thereby eliminating the excessive push-in.

  In the third embodiment described above, the side vertical wall 78 is the “guide vertical wall” in the fifth invention, and the vertical wall 78a and the vertical wall 78b are each the “vertical wall” in the fifth invention. It corresponds.

Pmax1, Pmax2, Pmax3 Displacement ends R1, R2 Radius 1 Internal combustion engine 10 Variable valve gear 12, 14 Rocker arm 14a Abutting portion 16 Rocker shaft 18 Camshaft 18a Cylindrical portion 20 Main cam 22 Sub cam 24, 26 Roller 27 Cam carrier 28 Valve 30 Valve spring 32 Switching mechanism 34, 36 Support shaft 34a, 36a Pin hole 38 Switching pin 40 Return spring 42 Piston 44 First slide arm 44a, 46a Arm portion 44b Slide arm pin 44c Press surface 44e Notch portion 46 Second slide Arm 48 Link shaft 48a Annular grooves 52, 66, 94 Guide rail 52a Start end 52b End 54 Electromagnetic solenoid 54a Drive shaft 60 Start linear groove 62 Spiral groove 64, 96 End linear groove 72 Sliding surface 77 Helical groove start position 78,80 side vertical wall 78a, 78b vertical wall 82 pin sliding amount 84,88,91 groove bottom surface 86 small projections 90 guide grooves 92 derived grooves 98 lift section 100 pin sliding amount 102 section

Claims (5)

An actuator that can project a pin;
A cylindrical portion that rotates with the camshaft;
A guide vertical wall that is formed on the outer peripheral surface of the cylindrical portion and guides relative displacement between the pin protruding from the actuator and the cylindrical portion;
A switching mechanism for switching the valve opening characteristics by the relative displacement;
Guiding means for guiding the pin protruding from the actuator to the guide vertical wall before the start of the relative displacement;
A variable valve operating apparatus for an internal combustion engine, comprising: The guiding means includes
A pin contact surface that is formed on the outer peripheral surface and contacts the pin protruding to the actuator before the start of the relative displacement;
The pin contact surface is an inclined surface inclined obliquely forward toward the guide vertical wall as viewed from the protruding direction of the pin;
The variable valve operating apparatus for an internal combustion engine according to claim 1. The guiding means includes
A pin contact surface that is formed on the outer peripheral surface and contacts the pin protruding to the actuator before the start of the relative displacement;
A small protrusion provided at the tip of the pin and smaller than the diameter of the pin;
An introduction groove that is provided on the pin contact surface and guides the inserted small protrusion along the groove;
The variable valve operating apparatus for an internal combustion engine according to claim 1, further comprising: The outer peripheral surface includes a concave guide groove having the contact surface having the introduction groove as a bottom surface and the guide vertical wall as one side surface,
The small protrusion is a hemispherical portion that is coaxial with the pin and whose diameter is smaller than the groove width of the introduction groove,
The distance between the axial center of the pin and the intermediate point of the groove width of the guide groove is not more than half of the difference between the groove width of the guide groove and the diameter of the pin;
The variable valve operating apparatus for an internal combustion engine according to claim 3. The guide vertical wall further comprises a vertical wall that guides the pin in the direction opposite to the direction of the displacement after guiding the relative displacement.
The variable valve operating apparatus for an internal combustion engine according to any one of claims 1 to 4.

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