JP2012087761A - Variable valve timing mechanism for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a space for a lost motion spring, and to improve mounting property of a variable valve timing mechanism into an internal combustion engine body.SOLUTION: In the variable valve timing mechanism for an internal combustion engine, valve lift characteristic is changed by changing phases of a cam follower and an oscillating cam relative to each other, and the lost motion spring energizes the oscillating cam. The lost motion spring formed into a cylindrical torsion spring, which surrounds the outer periphery of a control shaft, is connected to the internal combustion engine body in one axial end thereof, and the another axial end thereof is connected to the oscillating cam. A cylindrical spacer to be brought into contact with the internal combustion engine body in one axial end thereof and to be brought into contact with the oscillating cam in the another axial end thereof is disposed in the inner periphery of the lost motion spring. The outer peripheral part of the spacer on the internal combustion engine body side in the axial direction is pressed into the inner peripheral part of the lost motion spring, and on the another hand, a gap is provided between the outer peripheral part of the spacer on the oscillating cam side in the axial direction and the inner peripheral part of the lost motion spring.

Description

  The present invention relates to a variable valve operating apparatus for an internal combustion engine, and more particularly to a variable valve operating apparatus for an internal combustion engine in which a space occupied by a lost motion spring for returning the swing of a swing cam to a reference position is reduced.

  An internal combustion engine mounted on a vehicle or the like is driven to open and close by a drive cam provided on a camshaft of a valve gear so as to enhance combustion stability at low rotation and low load and ensure output at high rotation and high load. Some include a variable valve operating device that changes lift characteristics such as lift timing and lift amount of a valve composed of an intake valve and an exhaust valve in accordance with an operating state of the internal combustion engine.

  In a variable valve system for an internal combustion engine, a cam follower that is swung by a drive cam and a swing cam that is swung by the cam follower to open and close the valve are swingably supported by a control shaft. A lost motion spring is provided that changes the lift characteristics of the valve by changing the relative phase of the valve and urges the swing cam so that the cam follower always contacts the drive cam.

JP 2008-38722 A JP 2004-521234 A

However, the lost motion spring described in Patent Document 1 has a compression spring built in a dedicated pushing member, and the pushing member is held in the housing by a stopper so that it can be pushed in the swing cam direction. The number of parts is large.
In addition, the lost motion spring described in Patent Document 2 uses a hairpin-like spring that extends from one side to the other side across the rocking rotation point of the rocking cam. This occupies space and is a disadvantageous configuration in terms of layout.

  An object of the present invention is to reduce the space occupied by the lost motion spring and improve the mounting property to the internal combustion engine body.

  According to the present invention, a cam follower that is swung by a drive cam and a swing cam that is swung by the cam follower to open and close a valve are supported by a control shaft so as to be swingable. In the variable valve operating apparatus for an internal combustion engine, which changes the lift characteristic of the valve by changing the phase and urges the swing cam by a lost motion spring so that the cam follower always contacts the drive cam, the lost motion spring As a cylindrical torsion spring surrounding the outer periphery of the control shaft, one end in the axial direction is connected to the internal combustion engine body, the other end in the axial direction is connected to the swing cam, and one end in the axial direction is connected to the inner periphery of the lost motion spring. Has a cylindrical spacer that contacts the internal combustion engine body and the other axial end contacts the swing cam. The outer peripheral portion on the internal combustion engine body side in the axial direction of the spacer is press-fitted into the inner peripheral portion of the lost motion spring, while the outer peripheral portion on the swing cam side and the inner peripheral portion of the lost motion spring in the axial direction of the spacer. A gap is provided between the two.

In the variable valve operating apparatus for an internal combustion engine according to the present invention, the lost motion spring is arranged coaxially with the control shaft as a cylindrical torsion spring, so that the space occupied by the lost motion spring in the cylinder head can be reduced.
In the variable valve operating apparatus for an internal combustion engine according to the present invention, the lost motion spring can be positioned in the axial direction and the radial direction of the control shaft by the spacer.
Further, the variable valve operating apparatus for an internal combustion engine according to the present invention rotates the lost motion spring on the internal combustion engine main body side by press-fitting the outer peripheral portion on the internal combustion engine main body side into the inner peripheral portion of the lost motion spring in the axial direction of the spacer. Can be prevented, and the fixing method of the connecting portion for connecting the lost motion spring to the internal combustion engine side can be simplified.
In the variable valve device for an internal combustion engine according to the present invention, a gap is provided between the outer peripheral portion on the swing cam side and the inner peripheral portion of the lost motion spring in the axial direction of the spacer, so that the lost motion spring is twisted. The lost motion spring can be prevented from coming into contact with the outer peripheral surface of the spacer, and the drive loss due to the contact between the two can be reduced.
Therefore, the variable valve operating apparatus for an internal combustion engine according to the present invention can reduce the space occupied by the lost motion spring and improve the mountability to the internal combustion engine body.

FIG. 1 is a longitudinal sectional view of a control shaft portion of a variable valve operating apparatus. (Example) FIG. 2 is a plan view of the variable valve operating apparatus. (Example) FIG. 3 is a cross-sectional view of the variable valve operating apparatus taken along line AA in FIG. (Example) FIG. 4 is a perspective view of the variable valve operating apparatus. (Example) FIG. 5 is an exploded perspective view of the variable valve operating apparatus. (Example) 6A is a cross-sectional view of the variable valve operating device at the time of large lift / non-operation, and is a cross-sectional view taken along the line AA in FIG. 2, and FIG. 6B is a diagram of the variable valve operating device at the time of large lift / operation. FIG. 2 is a longitudinal sectional view of a position indicated by line AA in FIG. (Example) FIG. 7A is a cross-sectional view of the variable valve operating device at the time of small lift / non-actuation in FIG. 2, and FIG. 7B is a diagram of the variable valve operating device at the time of small lift / actuation. FIG. 2 is a cross-sectional view taken along line AA in FIG. (Example) FIG. 8 is a sectional view of the internal combustion engine. (Example) FIG. 9 is a perspective view of a cylinder head portion of the internal combustion engine. (Example)

  Embodiments of the present invention will be described below with reference to the drawings.

1 to 9 show an embodiment of the present invention. 8 and 9, reference numeral 1 denotes an internal combustion engine. In this embodiment, the crank axis of the internal combustion engine 1 is defined as the front-rear direction, the cylinder axis is defined as the vertical direction, and the direction orthogonal to the crank axis and the cylinder axis is defined as the left-right direction. The internal combustion engine 1 has a cylinder head 3 mounted on a cylinder block 2 to form a combustion chamber 4, and the cylinder head 3 is provided with two intake ports 5i and two exhaust ports 5e each communicating with the combustion chamber 4, and an intake port 5i And two intake valves 6i and two exhaust valves 6e for opening and closing the exhaust port 5e, respectively. The intake valve 6i and the exhaust valve 6e are urged in the valve closing direction by the intake valve spring 7i and the exhaust valve spring 7e, respectively.
The internal combustion engine 1 is provided with an intake roller rocker arm 8i and an exhaust roller rocker arm 8e that open and close an intake valve 6i and an exhaust valve 6e, respectively. The intake roller rocker arm 8i and the exhaust roller rocker arm 8e are supported at one end by an intake hydraulic lash adjuster 9i and an exhaust hydraulic lash adjuster 9e, respectively, and at the other end by an intake valve 6i and an exhaust valve 6e, respectively. It touches. The intake roller-type rocker arm 8i and the exhaust roller-type rocker arm 8e are swung on the other end side centered on one end side supported by the intake hydraulic lash adjuster 9i and the exhaust hydraulic lash adjuster 9e. Each of the valves 6e is moved in the axial direction.
In the internal combustion engine 1, a lower housing 10 is attached to the cylinder head 3 with bolts 11, and an upper housing 12 is attached to the lower housing 10 with bolts 13. Between the lower housing 10 and the upper housing 12, an intake cam shaft 14i and an exhaust cam shaft 14e, which are rotated by a half of the rotation of the crankshaft by a chain or a belt, are rotatably supported. The intake cam shaft 14i and the exhaust cam shaft 14e are provided with an intake drive cam 15i and an exhaust drive cam 15e for opening and closing the intake valve 6i and the exhaust valve 6e, respectively. The internal combustion engine 1 drives the intake valve 6i and the exhaust valve 6e by the intake drive cam 15i of the intake cam shaft 14i and the exhaust drive cam 15e of the exhaust cam shaft 14e, respectively, and opens and closes the intake port 5i and the exhaust port 5e.
In the internal combustion engine 1, a cylinder head cover 16 is attached to the lower housing 10 so as to cover the intake cam shaft 14i and the exhaust cam shaft 14e. A head side spark plug hole wall 17 reaching the combustion chamber 4 is formed in the cylinder head 3. The cylinder head cover 16 has a cover side spark plug hole wall 18 connected to the head side spark plug hole wall 17. A spark plug 19 is inserted into the head side spark plug hole wall 17 so as to face the combustion chamber 4 and be attached to the cylinder head 3. An ignition coil 20 for connecting to the spark plug 19 is inserted into the cover-side spark plug hole wall 18.

As described above, the internal combustion engine 1 is provided with the valve 6 including the intake valve 6i and the exhaust valve 6e for opening and closing the port 5 including the intake port 5i and the exhaust port 5e, and closing the intake valve 6i and the exhaust valve 6e, respectively. There is provided a valve spring 7 composed of an intake valve spring 7i and an exhaust valve spring 7e for urging the valve. In order to open and close the valve 6, the internal combustion engine 1 is provided with a drive cam 15 including an intake drive cam 15i and an exhaust drive cam 15e on a cam shaft 14 including an intake cam shaft 14i and an exhaust cam shaft 14e. Yes.
In the internal combustion engine 1, one end side of the roller rocker arm 8 including the intake roller rocker arm 8i and the exhaust roller rocker arm 8e is used as a hydraulic lash adjuster 9 including the intake hydraulic lash adjuster 9i and the exhaust hydraulic lash adjuster 9e. The other end of the roller rocker arm 8 is in contact with the valve 6. The internal combustion engine 1 drives the valve 6 by swinging the other end side of the roller type rocker arm 8 supported at one end side by the hydraulic lash adjuster 9 by the drive cam 15.
As described above, the internal combustion engine 1 swings the roller rocker arm 8 supported by the hydraulic lash adjuster 9 by the drive cam 15 of the cam shaft 14 and drives the valve 6 urged in the valve closing direction by the valve spring 7. Open and close port 5.

The internal combustion engine 1 includes a variable valve gear 21 that changes the lift characteristics of the valve 6 including an intake valve 6i or an exhaust valve 6e. 8 and 9, the variable valve operating device 21 is provided on the intake valve 6i side, but may be provided on the exhaust valve 6e side. Therefore, the following description will be made using the terms of the port 5, the valve 6, the valve spring 7, the roller rocker arm 8, the hydraulic lash adjuster 9, the cam shaft 14, and the drive cam 15.
As shown in FIGS. 4 and 5, the valve 6 includes two valves, a one-side valve 6A and an other-side valve 6B arranged side by side in the front-rear direction. The one-side valve 6A includes a one-side valve head 21A that is brought into contact with and separated from the opening of the one-side port 5A, and a one-side valve stem 22A having a tip side connected to the one-side valve head 21A. The other-side valve 6B includes an other-side valve head 21B that is brought into contact with and separated from the opening of the other-side port 5B, and an other-side valve stem 22B having a distal end connected to the other-side valve head 21B.
The one side valve 6A and the other side valve 6B are supported by the cylinder head 3 so that the one side valve stem 22A and the other side valve stem 22B can move in the axial direction, and are closed by the one side valve spring 7A and the other side valve spring 7B, respectively. Is biased in the direction.

The internal combustion engine 1 is provided with a one-side roller rocker arm 8A and another roller-type rocker arm 8B that open and close the one-side valve 6A and the other-side valve 6B. The one side roller type rocker arm 8A and the other side roller type rocker arm 8B are supported at one end side by the one side hydraulic lash adjuster 9A and the other side hydraulic lash adjuster 9B, and are swung at the other end side. The valve 6B is moved in the axial direction to open and close the one side port 5A and the other side port 5B.
The one-side roller type rocker arm 8A is disposed so as to extend rightward from the one-side hydraulic lash adjuster 9A, the right end abuts against the base end of the one-side valve stem 22A, and the one-side roller oriented in the front-rear direction at the center The one side roller 24A is pivotally supported by the shaft 23A, and the right end portion is supported on the spherical top portion of the one side hydraulic lash adjuster 9A.
The other-side roller type rocker arm 8B is disposed so as to extend rightward from the other-side hydraulic lash adjuster 9B, abuts against the base end of the other-side valve stem 22B at the right end, and is directed to the front and rear in the center. The other side roller 24B is pivotally supported by the shaft 23B, and the right end portion is supported on the spherical top portion of the other side hydraulic lash adjuster 9B.
As shown in FIGS. 1 and 3, the internal combustion engine 1 has one side (front side) oriented in the front-rear direction as shown in FIGS. It is rotatably supported between the lower housing 10 and the upper housing 12 and between the lower housing 10 on the other side (rear side) and the other upper housing 12. The camshaft 14 is provided with a drive cam 15 for opening and closing the one side valve 6A and the other side valve 6B. The drive cam 15 has a shape of a base circle 25 that does not lift the one-side valve 6A and the other-side valve 6B, and a shape that lifts the one-side valve 6A and the other-side valve 6B that protrude in the radial direction from the base circle 25. It consists of a lift part 26.

  The variable valve mechanism 21 includes a control shaft 27 that is parallel to the cam shaft 14 and extends in the front-rear direction. The control shaft 27 is disposed above the one side roller type rocker arm 8A and the other side roller type rocker arm 8B. As shown in FIG. 1, the control shaft 27 is disposed between the one side lower housing 10 and the upper housing 12 and on the other side lower. It is rotatably supported between the housing 10 and the upper housing 12. The control shaft 27 is rotationally controlled by an actuator composed of a motor or the like. The actuator is driven and controlled by the control means.

The control shaft 27 supports a cam follower 28 that is swung by the drive cam 15 and a swing cam 29 that is swung by the cam follower 28 to open and close the one side valve 6A and the other side valve 6B. ing.
As shown in FIG. 5, the cam follower 28 includes two cylindrical boss portions 30, 30 through which the control shaft 27 slidably passes. The two boss portions 30 and 30 are connected by a connecting portion 31 with a gap therebetween. The boss portions 30 and 30 include a roller support portion 32 that protrudes toward the camshaft 14 side and has a distal end branched in a substantially U shape in plan view. A cam roller 33 that is in contact with the drive cam 15 is pivotally supported by a roller shaft 34 at the tip of the roller support portion 32.
The rocking cam 29 is disposed on both sides of the two boss portions 30 and 30 of the cam follower 28, and has a one-side rocking cam 29A that rocks the one-side roller rocker arm 8A disposed in the front, and the rear. The other-side rocker cam 29B that rocks the other-side roller type rocker arm 8B is disposed. The one-side oscillating cam 29A and the other-side oscillating cam 29B include a cylindrical one-side boss portion 35A and other-side boss portion 35B through which the control shaft 27 slidably passes, and project toward the cam shaft 14 side. It is supported by the control shaft 27 as described above. The one-side boss portion 35A and the other-side boss portion 35B are arranged so as to sandwich the two boss portions 30 and 30 of the cam follower 28, and are connected by a connecting portion 36.
The one-side swing cam 29A has a one-side cam surface 37A for opening and closing the one-side valve 6A on the outer periphery facing the one-side roller 24A of the one-side roller type rocker arm 8A. The one-side cam surface 37A has an arc shape centered on the axis C1 of the control shaft 27, and a one-side base circle portion 38A that does not lift the one-side valve 6A, and the camshaft 14 from the one-side base circle portion 38A. It consists of a one-side lift part 39A that protrudes to the side and lifts the one-side valve 6A and is pressed by the one-side roller 24A.
As shown in FIG. 3, the other-side swing cam 29B has an other-side cam surface 37B that opens and closes the other-side valve 6B on the outer periphery facing the other-side roller 24B of the other-side roller type rocker arm 8B. . The other-side cam surface 37B has an arc shape centered on the axis C1 of the control shaft 27, and has a shape that prevents the other-side valve 6B from being lifted, and a radially outer side from the other-side base circle portion 38B. And the other side lift portion 39B that lifts the other side valve 2B and is pressed by the other side roller 24B.

The variable valve operating device 21 is provided with drive arms 40 and 40 extending outward from the center of swing on the two boss portions 30 and 30 of the cam follower 28, respectively. The two drive arms 40 and 40 have shafts 41 parallel to the control shaft 27 at their tips. The shaft 41 supports a rotating member 42 that rotates about the shaft 41.
The rotating member 42 includes a rotating member side gear portion 43 on the peripheral surface on the side facing the control shaft 27 between the two boss portions 30. A control shaft side gear portion 44 that meshes with the rotation member side gear portion 43 is attached to the control shaft 27 between the two boss portions 30, 30 on the circumferential surface facing the rotation member 42. A first contact portion 45 is disposed on the rotation member 42 on the opposite side of the rotation member side gear portion 43 with the rotation center of the shaft 41 interposed therebetween. The rotation member 42 is provided with an attachment hole 46 on the opposite side of the rotation member side gear portion 43 across the rotation center of the shaft 41, and the first contact portion 45 is attached to the attachment hole 46 via a position adjustment mechanism 47. Yes.
The first contact portion 45 is formed in a plate shape in which the front side is a curved surface and the back side is a flat surface whose both end surfaces are connected to the curved surface. The position adjusting mechanism 47 is fixed to the back side of the first contact portion 45 and faces the screw shaft 48 penetrating the mounting hole 46, the first contact portion 45 and the first contact portion 45 of the rotating member 42. And a mounting nut 50 that is screwed into a screw shaft 48 penetrating the mounting hole 46 and mounts the first contact portion 45 to the rotating member 42. The first contact portion 45 can adjust the attachment position with respect to the rotation member 42 by changing the thickness of the shim 49 disposed between the first contact portion 45 and the rotation member 42.

  The variable valve operating device 21 extends outward from the swing center to the one-side oscillating cam 29A and the other-side oscillating cam 29B that constitute the oscillating cam 29. One side driven arm 51A and the other side driven arm 51B are provided. The one-side driven arm 51A and the other-side driven arm 51B are connected to the distal ends of the one-side driven arm 51A and the other-side driven arm 51B, and the second contact portion is in contact with the first contact portion 45. 52 is provided.

This variable valve operating device 21 is provided with a one-side lost motion spring 53A and another-side lost motion spring 53B that urges the swing cam 26 so that the cam follower 28 always contacts the drive cam 15. The one-side lost motion spring 53 </ b> A and the other-side lost motion spring 53 </ b> B are cylindrical torsion springs that surround the outer periphery of the control shaft 27.
As shown in FIG. 2, the one-side lost motion spring 53A is provided with an internal combustion engine one-side connection portion 54A at one axial end (front side), and a swing cam one-side connection at the other axial end (rear side). A portion 55A is provided. The one-side lost motion spring 53A connects the one-side connection portion 54A for the internal combustion engine to the one-side attachment portion 56A formed on the front upper housing 12 constituting the internal combustion engine body, and the one-side connection portion 55A for the swing cam. The one side swing cam 29A is connected to one side driven arm 51A.
The other-side lost motion spring 53B includes the other-side coupling portion 54B for the internal combustion engine at the other axial end (rear side) and the other-side coupling portion 55B for the swing cam at one axial end (front side). Yes. The other-side lost motion spring 53B connects the other-side connection portion 54B for the internal combustion engine to the other-side attachment portion 56B formed on the rear upper housing 12 constituting the internal combustion engine body, and the other-side connection portion 55B for the swing cam. Is connected to the other driven arm 51B of the other swing cam 29B.

As shown in FIG. 1, a cylindrical one-side spacer 57A is arranged on the inner periphery of the one-side lost motion spring 53A. The one-side spacer 57A makes one large-diameter portion 58A on one axial end (front side) in contact with the front lower housing 10 and the upper housing 12 constituting the internal combustion engine body, and one axial other end (rear side). The side small diameter portion 59A is brought into contact with the one side boss portion 35A of the one side swing cam 29A. The one-side spacer 57A is formed only of an end portion on the one-side small diameter portion 59A side that contacts the one-side swing cam 29A in the axial direction with a material having higher wear resistance than the other portions.
The one-side spacer 57A presses the outer peripheral portion of the one-side large-diameter portion 58A on the side in contact with the front lower housing 10 and the upper housing 12 in the axial direction into the inner peripheral portion of the one-side lost motion spring 53A. Yes. On the other hand, the one-side spacer 57A is between the outer peripheral portion of the one-side small diameter portion 59A and the inner peripheral portion of the one-side lost motion spring 53A on the side in contact with the one-side boss portion 35A of the one-side swing cam 29A in the axial direction. In addition, a one-side gap 60A is provided.
The one-side lost motion spring 53A is disposed on the outer periphery of the control shaft 27 via the one-side spacer 57A, and the circumferential interval between the one-side connection portion 54A for the internal combustion engine and the one-side connection portion 55A for the swing cam is set. The lower housing 10 and the upper housing 12 that are twisted so as to be contracted and constitute the main body of the internal combustion engine are disposed between the one-side swing cam 29A. The one-side swing cam 29A is rotated in a direction to close the one-side valve 6A by the elastic force of the one-side lost motion spring 53A. Then, the cam follower 28 is rotated by the force by which the one-side driven arm 51A of the one-side swing cam 29A pushes the drive arms 40, 40 of the cam follower 28, and the cam roller 33 held by the roller support portion 32 is driven to the drive cam 15 Contact.

Further, a cylindrical other-side spacer 57B is disposed on the inner periphery of the other-side lost motion spring 53B. The other side spacer 57B contacts the other side large diameter portion 58B of one axial end (rear side) with the rear lower housing 10 and the upper housing 12 constituting the internal combustion engine main body, and at the other axial end (front side). The other side small diameter portion 59B is brought into contact with the other side boss portion 35B of the other side swing cam 29B. In the other side spacer 57B, only the end portion on the other side small diameter portion 59B side that contacts the other side swing cam 29B in the axial direction is formed of a material having higher wear resistance than the other portions.
The other-side spacer 57B press-fits the outer peripheral portion of the other-side large-diameter portion 58B on the side in contact with the lower housing 10 and the upper housing 12 in the axial direction into the inner peripheral portion of the other-side lost motion spring 53B. ing. On the other hand, the other-side spacer 57B is between the outer peripheral portion of the other-side small diameter portion 59B on the side contacting the other-side boss portion 35B of the other-side swing cam 29B in the axial direction and the inner peripheral portion of the other-side lost motion spring 53B. The other side clearance 60B is provided.
The other-side lost motion spring 53B is disposed on the outer periphery of the control shaft 27 via the other-side spacer 57B, and the circumferential interval between the other-side connecting portion 54B for the internal combustion engine and the other-side connecting portion 55B for the swing cam is set. The lower housing 10 and the upper housing 12 which are twisted so as to be contracted and constitute the main body of the internal combustion engine are disposed between the other side swing cam 29B. The other-side swing cam 29B is rotated in a direction to close the other-side valve 6B by the elastic force of the other-side lost motion spring 53B. Then, the cam driven follower 28 is rotated by the force by which the other driven arm 51B of the other swing cam 29B pushes the drive arms 40, 40 of the cam follower 28, and the cam roller 33 held by the roller support portion 32 is driven into the drive cam 15. Contact.

Next, the lift of the one side valve 6A and the other side valve 6B by the variable valve operating device 21 will be described with reference to FIGS.
6 and 7, the axis of the control shaft 27 is C1, the axis of the shaft 41 is C2, the horizontal reference line passing through the axis C1 of the control shaft 27 is H, and the axis C2 of the shaft 41 is C2. A vertical reference line passing through V, V1, a line segment passing through the axis C1 of the control shaft 27 and the end point E of the control shaft side gear portion 44, L1, and the axis C2 of the shaft 41, the first contact portion 45 and the second contact. L2 is a line segment passing through the contact point T of the part 52, L3 is a line segment passing through the axis C1 of the control shaft 27 and the contact point T of the first contact part 45 and the second contact part 52, and a reference line H and a line In the following description, the angle formed by the segment L1 is α, the angle formed by the reference line V and the line segment L2 is β, and the angle formed by the reference line H and the line segment L3 is γ.
The variable valve operating device 21 interlocks with the cam follower 28 to cause the one-side swing cam 29A and the other-side swing cam 29B to swing in synchronism so that the one-side valve 6A and the other-side valve 6B have the same lift amount. 6 and 7, the lift of the other side valve 6 </ b> B by the other side swing cam 29 </ b> B will be described as a representative.

The variable valve operating device 21 operates as shown in FIG. 6 when the other valve 6B is lifted greatly. As shown in FIG. 6 (A), the variable valve gear 21 has a control shaft side gear portion before the valve lift at the large lift position where the base circle portion 25 of the drive cam 15 is in contact with the cam roller 33. When the angle of 44 with respect to the reference line H is α1, the angle with respect to the reference line V of the first contact portion 45 of the rotating member 42 having the rotating member side gear portion 43 that meshes with the control shaft side gear portion 44 is β1. At this time, the angle with respect to the reference line H of the second contact portion 52 connected to the other-side rocking cam 29B is γ1.
In this state, in the variable valve operating device 21, the substantially boundary between the other base circular portion 38B and the other lift portion 39B of the other swing cam 29B is in contact with the other roller 24B of the other roller type rocker arm 8B. Therefore, the other side valve 6A is not lifted (closed state) without pushing down the other side roller type rocker arm 8B.
When the camshaft 14 rotates in the direction of the arrow R1, as shown in FIG. 6B, the variable valve mechanism 21 is lifted from the valve closed state before lift shown in FIG. 6A. Contacts the cam roller 33 and swings the cam follower 28 downward. The cam follower 28 that swings downward rotates the other-side swing cam 29 </ b> B in the direction of arrow R <b> 2 by the first contact portion 45 that contacts the second contact portion 52. The other side swing cam 29B is rotated in the direction of the arrow R2, and the part away from the other side base circle 38B of the other side lift part 39B contacts the other side roller 24B of the other side roller type rocker arm 8B. The roller type rocker arm 8B is largely pushed down to bring the side valve 6A into a large lift state (valve open state).

The variable valve operating device 21 operates as shown in FIG. 7 when the other valve 6A is slightly lifted. As shown in FIG. 7 (A), the variable valve operating device 21 starts the control shaft 27 from the state shown in FIG. 7 (A) from the state shown in FIG. By rotating in the arrow R3 direction, the angle formed by the control shaft side gear 44 with respect to the reference line H is changed from α1 to α2. The rotation of the control shaft side gear portion 44 causes the rotation member 42 provided with the rotation member side gear portion 43 meshing with the control shaft side gear portion 44 to rotate in the direction of arrow R4, and the angle of the first contact portion 45 with respect to the reference line V is It decreases from β1 to β2. Thereby, the angle with respect to the reference line H of the 2nd contact part 52 connected with the other side rocking cam 29B reduces from (gamma) 1 to (gamma) 2.
In this state, the variable valve operating device 21 is such that the part away from the other side lift part 39B of the other side base circle 38B of the other side swing cam 29B comes into contact with the other side roller 24B of the other side roller type rocker arm 8B. Therefore, the other side valve 6A is not lifted (the valve is closed) without pushing down the other side roller type rocker arm 8B.
When the camshaft 14 rotates in the direction of the arrow R5 as shown in FIG. 7B from the closed state before the lift shown in FIG. 7A, the variable valve device 21 lifts 26 of the drive cam 15. Comes into contact with the cam roller 33 and the cam follower 28 swings downward. The cam follower 28 that swings downward rotates the other-side swing cam 29 </ b> B in the direction of the arrow R <b> 6 by the first contact portion 45 that contacts the second contact portion 52. The other-side swing cam 29B rotates in the direction of arrow R6, and the portion close to the other-side base circle 38B of the other-side lift portion 39B contacts the other-side roller 24B of the other-side roller type rocker arm 8B. The type rocker arm 8B is pushed down to bring the side valve 6A into a small lift state (open valve state).

  The variable valve operating device 21 interlocks with the cam follower 28 to cause the one-side swing cam 29A and the other-side swing cam 29B to swing synchronously, and lift the one-side valve 6A and the other-side valve 6B with the same lift amount. Therefore, the one-side valve 6A is also lifted by the one-side swing cam 29A in the same manner as the lift of the other-side valve 6B by the other-side swing cam 29B described above.

As described above, the variable valve device 21 of the internal combustion engine 1 changes the lift characteristics of the valve 6 by changing the relative phases of the cam follower 28 and the swing cam 29 that are swingably supported on the control shaft 27. is doing. Further, the variable valve operating device 21 is provided with a lost motion spring 53 that urges the swing cam 29 against the cam follower 28 so that the cam follower 28 is always in contact with the drive cam 15 of the cam shaft 14.
The variable valve device 21 has a lost motion spring 53 as a cylindrical torsion spring that surrounds the outer periphery of the control shaft 27, one axial end of which is connected to the upper housing 12 of the internal combustion engine 1, and the other axial end is a swing cam. The cylinder is connected to the driven arm 51 of the 29, and the axial end of the lost motion spring 53 is in contact with the lower housing 10 and the upper housing 12 of the internal combustion engine 1 and the other end of the axial motion is in contact with the swing cam 29. A spacer 57 is arranged.
The spacer 57 press-fits the outer peripheral portion on the lower housing 10 and upper housing 12 side of the internal combustion engine 1 in the axial direction to the inner peripheral portion of the lost motion spring 53, and the outer peripheral portion on the swing cam 29 side in the axial direction and lost. A gap 60 is provided between the inner peripheral portions of the motion spring 53.

As a result, the variable valve device 21 of the internal combustion engine arranges the lost motion spring 53 coaxially with the control shaft 27 as a cylindrical torsion spring, so that the space occupied by the lost motion spring 53 in the cylinder head 3 is reduced. be able to. Further, the variable valve device 27 of the internal combustion engine 1 can position the lost motion spring 53 in the axial direction and the radial direction of the control shaft 27 by the spacer 57.
Further, the variable valve operating device 21 of the internal combustion engine 1 presses the outer peripheral portion of the lower housing 10 and the upper housing 12 side into the inner peripheral portion of the lost motion spring 53 in the axial direction of the spacer 57, so that the lost motion spring 53 The rotation of the lower housing 10 and the upper housing 12 can be prevented, and the fixing method of the connecting portion 54 that connects the lost motion spring 53 to the internal combustion engine 1 can be simplified.
Further, in the variable valve operating device 27 of the internal combustion engine 1, the gap 60 is provided between the outer peripheral portion on the swing cam 29 side and the inner peripheral portion of the lost motion spring 53 in the axial direction of the spacer 57. The lost motion spring 53 can be prevented from coming into contact with the outer peripheral surface of the spacer 57 when the twist is twisted, and the drive loss due to the contact between the two can be reduced.
Therefore, the variable valve device 27 of the internal combustion engine 1 can reduce the space occupied by the lost motion spring 53 and improve the mounting property to the internal combustion engine body.
Further, in the variable valve device 21 of the internal combustion engine 1, since the spacer 57 itself does not rotate, the spacer 57 only needs to be formed of a material having high wear resistance at the end on the swing cam 29 side. The entire 57 need not be made of a highly wear resistant material.

  INDUSTRIAL APPLICABILITY The variable valve operating apparatus for an internal combustion engine according to the present invention can reduce the space occupied by the lost motion spring and improve the mounting property to the internal combustion engine body, and can be applied to various internal combustion engines.

DESCRIPTION OF SYMBOLS 1 Internal combustion engine 3 Cylinder head 6A One side intake valve 6B The other side intake valve 8A One side roller type rocker arm 8B The other side roller type rocker arm 9A One side hydraulic lash adjuster 9B The other side hydraulic lash adjuster 14 Cam shaft 15 Drive cam 27 Control shaft 28 Cam follower 29A One side swing cam 29B Other side swing cam 37A One side cam surface 37B Other side cam surface 42 Rotating member 43 Rotating member side gear portion 44 Control shaft side gear portion 45 First contact portion 47 Position adjusting mechanism 52 Second Contact part 53A One side lost motion spring 53B Other side lost motion spring 54A One side connection part for internal combustion engine 54B One side connection part for internal combustion engine 55A One side connection part for rocking cam 55B One side connection part for rocking cam 57A One Side spacer 58A One side large diameter part 59A One side small diameter part 60A One side During 57B other side spacer 58B the other side large-diameter portion 59B other side small-diameter portion 60B other side gap

Claims (2)

A cam follower that is swung by a drive cam and a swing cam that is swung by this cam follower to open and close a valve are supported on a control shaft in a swingable manner.
An internal combustion engine that changes the lift characteristics of the valve by changing the relative phase of the cam follower and the swing cam and urges the swing cam by a lost motion spring so that the cam follower always contacts the drive cam In the variable valve gear of
The lost motion spring is a cylindrical torsion spring surrounding the outer periphery of the control shaft, and one axial end thereof is connected to the internal combustion engine body, and the other axial end is connected to the swing cam.
A cylindrical spacer is disposed on the inner periphery of the lost motion spring, with one axial end contacting the internal combustion engine body and the other axial end contacting the swing cam.
While pressing the outer peripheral part of the internal combustion engine main body side in the axial direction of the spacer into the inner peripheral part of the lost motion spring,
A variable valve operating apparatus for an internal combustion engine, wherein a gap is provided between an outer peripheral portion on the swing cam side and an inner peripheral portion of the lost motion spring in the axial direction of the spacer.   2. The variable valve operating apparatus for an internal combustion engine according to claim 1, wherein the spacer is formed only of an end portion on the swing cam side in an axial direction with a material having higher wear resistance than other portions. .

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