JP4135546B2 - Variable valve gear for engine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a variable valve gear for an engine.
[0002]
[Prior art]
  It is generally known that the opening / closing timing and valve lift amount of the intake / exhaust valve of the engine are changed in accordance with the operating state of the engine. As an example of such a variable valve device, an outer ring is fitted to an eccentric ring provided on a camshaft, while a swinging cam for lifting an intake valve is supported on the camshaft so as to be swingable, and the eccentric ring rotates. The displacement of the outer ring is transmitted to the swing cam by the link means, and this link means is constituted by a rocker arm connected to the outer ring and a link connected to the swing cam, and the rocker arm swing support point and the swing cam shaft A device in which the distance from the mind is changed in accordance with the operating state of the engine is known (see Patent Document 1).
[0003]
  According to this variable valve operating system, at the time of high engine speed and high load, the rocker arm's rocking fulcrum is brought close to the rocking cam shaft so that the valve opening start time is advanced and the valve lift amount is increased. By releasing the swing fulcrum at the time of loading, the valve opening start timing can be delayed to reduce the valve lift amount.
[0004]
  As another example of a variable valve system, a support arm is rotatably supported on a camshaft, and the rocker arm is swingably supported at the tip of the support arm, and the support arm is rotated at low engine speed and low load. There is also known an attempt to reduce the valve lift amount without delaying the valve opening start timing by displacing the rocking fulcrum of the rocker arm around the axis of the camshaft (see Patent Document 2).
[0005]
[Patent Document 1]
        JP-A-11-107725
[Patent Document 2]
        JP-A-11-264307
[0006]
[Problems to be solved by the invention]
  However, as described in Patent Document 1, not only the valve lift amount becomes small at the time of engine low rotation and low load, but also in a variable valve system in which the valve opening start timing is delayed, this is applied to the intake valve. In this case, when the valve lift amount is small, it is impossible to secure an overlap period between the exhaust valve and the intake valve. For this reason, there are disadvantages such as being disadvantageous for the emission of combustion exhaust gas, being unable to obtain the internal EGR effect, and being unable to reduce the pumping loss.
[0007]
  On the other hand, an attempt to reduce the valve lift amount without delaying the valve opening start timing as described in Patent Document 2 requires an arm that supports the rocker arm and an actuator that displaces the support arm. As the number of points increases, the variable valve operating device becomes complicated, and the weight increases.
[0008]
  Accordingly, an object of the present invention is to make it possible to change the valve lift amount without greatly changing the valve opening start timing while reducing the number of parts and satisfying weight reduction and reliability. .
[0009]
  Another object of the present invention is to make it possible to greatly change the valve lift amount.
[0010]
  Another object of the present invention is to provide a variable valve device that can be incorporated into an existing engine while suppressing an increase in the overall height of the engine and without making a major design change.
[0011]
[Means for Solving the Problems]
  In order to solve such a problem, the present invention provides a variable valve operating apparatus in which an eccentric ring and an outer ring are used to swing a swing cam for a valve lift. It is connected and the displacement of the outer ring accompanying the rotation of the eccentric ring is restricted by the link means.
[0012]
  That is, the invention according to claim 1 is a camshaft having an eccentric wheel that rotates in synchronization with a crankshaft of an engine;
  A swing cam that lifts the valve provided to swing about the camshaft;
  An outer ring rotatably fitted on the eccentric ring,
  A link mechanism for connecting the swing cam and the outer ring, and transmitting a displacement of the outer ring to the swing cam;
  A regulation link connected to the outer ring and regulating the displacement of the outer ring accompanying the rotation of the eccentric ring so that the swing cam swings via the link mechanism;
  And a control member that changes the position of the restriction link according to the operating state of the engine.e,
the aboveIn order to change the lift amount of the valve by the swing cam, and so that the peak of the valve lift appears at the rotation angle on the front side in the rotation direction of the camshaft at the time of the small lift control than at the time of the large lift control.By the control memberThe position of the restriction link was changedA variable valve operating system for an engine,
The outer ring is disposed between the link mechanism and the restriction link in the axial direction of the camshaft,
The restricting link is rotatably provided about an axis parallel to the camshaft and is connected to the outer ring, and the connection point between the outer ring and the link mechanism moves in a reciprocating arc motion as the eccentric wheel rotates. Restricting the displacement of the outer ring to
The control member changes the position of the rotation shaft of the restriction link so that the reciprocating arc motion position of the connection point is displaced in the circumferential direction around the axis of the camshaft.It is characterized byThe
[0013]
  Therefore, when the eccentric wheel rotates as the camshaft rotates, the connection point between the outer ring and the link mechanism is restricted by the restriction link.Reciprocating arcThe outer ring is moved, and the displacement of the outer ring is transmitted to the swing cam via the link mechanism. The swing cam swings to lift the valve. When the position of the restriction link is changed by the control member, the movement locus of the connection point between the outer ring and the link mechanism is changed accordingly, the swing mode of the swing cam is changed, and the valve lift amount is changed.
[0014]
  Then, the link mechanism and the regulation linkAxial direction of the camshaftSince it is linked in the middle, it becomes easy to change the position of the restriction link by the control member to displace the connection point between the outer ring and the link mechanism around the axis of the camshaft, and the position of the restriction link can be changed. It is possible to greatly change the valve lift amount by the swing cam so as to achieve throttleless (abolition of the throttle valve).
[0015]
  Moreover,Since the connection point between the outer ring and the link mechanism is moved in an arc, the restriction link may be provided so as to be rotatable about an axis parallel to the camshaft, and the structure of the restriction link is simplified. In addition, since the arc movement position of the connecting point is moved around the camshaft axis by changing the position of the rotation shaft of the restriction link by the control member, the camshaft is smaller in the small lift control than in the large lift control. The valve opening start timings of the valves can be substantially aligned so that the maximum lift appears at the rotation angle on the near side in the rotation direction. Thus, since the control member itself also changes the position of the rotation shaft of the restriction link, its configuration is simplified.
[0016]
The invention according to claim 2 is the variable valve operating apparatus for the engine according to claim 1,
The link mechanism includes a single link that connects the swing cam and the outer ring, and one end of each of the link and the restriction link is rotatably connected to the outer ring. To do.
[0017]
Therefore, it is possible to simplify the configuration by reducing the number of parts of the variable valve operating device, which is advantageous for downsizing and weight reduction, and the number of link connection points is reduced, which causes the link to be twisted. This is advantageous in improving the reliability of the variable valve operating apparatus by avoiding the occurrence of a link connection point where a large load is applied.
[0018]
  The invention according to claim 3A camshaft having an eccentric wheel that rotates in synchronization with the crankshaft of the engine;
A swing cam that lifts the valve provided to swing about the camshaft;
An outer ring rotatably fitted on the eccentric ring,
A link mechanism for connecting the swing cam and the outer ring, and transmitting a displacement of the outer ring to the swing cam;
A regulation link connected to the outer ring and regulating the displacement of the outer ring accompanying the rotation of the eccentric ring so that the swing cam swings via the link mechanism;
A control member that changes the position of the restriction link according to the operating state of the engine,
The control of the valve lift so that the lift amount of the valve by the swing cam changes, and the peak of the valve lift appears at the rotation angle closer to the camshaft rotation direction than at the time of large lift control at the time of small lift control. A variable valve operating apparatus for an engine that changes the position of the restriction link by a member,
The outer ring is disposed between the link mechanism and the restriction link in the axial direction of the camshaft,
  The link mechanism includes a single link that connects the swing cam and the outer ring, and one end of each of the link and the restriction link is rotatably connected to the outer ring. To do.
[0019]
Therefore, when the eccentric wheel rotates along with the rotation of the camshaft, the connection point between the outer ring and the link mechanism moves along a predetermined locus restricted by the restriction link, and the displacement of the outer ring moves through the swing mechanism via the link mechanism. The swing cam swings and the valve lifts. When the position of the restriction link is changed by the control member, the movement locus of the connection point between the outer ring and the link mechanism is changed accordingly, the swing mode of the swing cam is changed, and the valve lift amount is changed.
[0020]
Then, since the link mechanism and the restriction link link the outer ring in the middle of the camshaft in the axial direction, the position of the restriction link is changed by the control member to change the connection point between the outer ring and the link mechanism. It becomes easy to displace the camshaft around the shaft center, and the valve lift amount by the swing cam can be changed greatly by changing the position of the regulation link greatly. It can also be achieved. Also, when changing the valve lift amount, the position of the restriction link is changed so that the peak of the valve lift appears at the rotation angle closer to the camshaft rotation direction than at the time of large lift control at the time of small lift control. The valve opening start timing itself can be easily aligned regardless of the change in the valve lift amount.
[0021]
  In addition, the link mechanism is composed of a single link that connects the swing cam and the outer ring, and each end of the link and the restriction link is rotatably connected to the outer ring. ,The number of parts of the variable valve system can be reduced to simplify the structure, which is advantageous for making it compact and lightweight, and the number of link connection points is reduced. This is advantageous in improving the reliability of the variable valve operating apparatus by avoiding the occurrence of a link connection point where a load is applied.
[0022]
  The invention according to claim 4Claim 2 or claim 3In the variable valve operating apparatus for an engine described in 1.
  The restriction link is pivotally connected to the control member by an axis parallel to the camshaft, and a connection point between the outer ring and the link mechanism is connected to the control member and the link with the rotation of the eccentric ring. Reciprocating arc motion around the connection point with the restriction linkIt is characterized by that.
[0023]
  Therefore,The configuration of the regulatory link is simplified.
[0024]
  Claim 5The invention according to claim 1Any one of Claim 4In the variable valve operating apparatus for an engine described in 1.
  The control member rotates around an axis parallel to the camshaft.
  The connection point between the outer ring and the link mechanism is disposed above the camshaft,
  The rotation shaft of the control member is arranged on the side of the connection point.
[0025]
  Therefore, the entire variable valve operating device does not become bulky, and it is advantageous in incorporating an existing engine without restraining an increase in the overall height of the engine and making a major design change.
[0026]
  Claim 6The invention according to claim 1 to claim 1Claim 5In the variable valve operating apparatus for an engine according to any one of
  The rocking cam is in contact with a direct acting tappet.
[0027]
  Therefore, it is advantageous in incorporating an existing engine equipped with a direct-acting tappet without restraining an increase in the overall height of the engine and making a major design change.
[0028]
【The invention's effect】
  As described above, according to the first aspect of the present invention, the swing cam for lifting the valve and the outer ring fitted to the eccentric ring of the camshaft are connected by the link mechanism, and the restriction link is connected to the outer ring. To regulate the displacement of the outer ringAndThe valve lift amount is changed by changing the position of the restriction link with the control member, and the peak of the valve lift appears at the rotation angle closer to the camshaft rotation direction than at the large lift control at the time of small lift control.In the variable valve operating apparatus, the outer ring is arranged in the camshaft axial direction between the link mechanism and the restriction link, and the connection point between the outer ring and the link mechanism undergoes a reciprocating arc motion as the eccentric wheel rotates. The restriction link is pivotally provided around an axis parallel to the camshaft and connected to the outer ring, and the reciprocating arc motion position of the connecting point is a circumferential direction around the axis of the camshaft. The position of the pivot shaft of the restriction link is changed by the control member so as to be displacedTherefore, while reducing the number of parts to satisfy weight reduction and reliability, it is possible to change the valve lift amount while ensuring the desired valve overlap period by substantially aligning the valve opening start timing, The lift amount can be changed greatly, which is advantageous for throttle-less (reducing pumping loss during small lift control and improving intake charging efficiency during large lift control).On top of that,Structure of variable valve gearButIt becomes simple, which is advantageous for making it compact and lightweight.
[0029]
According to the invention of claim 2, in claim 1,The link mechanism is configured by a single link that connects the swing cam and the outer ring, and one end of each of the link and the restriction link is rotatably connected to the outer ring. The configuration can be simplified by reducing the number of parts, which is advantageous in reducing the size and weight, and in improving the reliability of the variable valve operating apparatus.
[0030]
  According to the invention of claim 3,The swing cam that lifts the valve and the outer ring fitted to the eccentric ring of the camshaft are connected by a link mechanism, while the outer ring is connected to a restriction link to restrict the displacement of the outer ring, and the position of the restriction link is controlled by the control member. In the variable valve operating apparatus, the valve lift amount is changed by changing the valve lift amount, and the peak of the valve lift appears at the rotation angle closer to the camshaft rotation direction than at the time of large lift control at the time of small lift control. An outer ring is arranged between the link mechanism and the restriction link in the camshaft axial direction,The link mechanism is configured by a single link that connects the swing cam and the outer ring, and one end of each of the link and the restriction link is rotatably connected to the outer ring.While reducing the number of parts to satisfy weight reduction and reliability, the valve lift amount can be changed while the valve opening start timing is substantially aligned to ensure the desired valve overlap period. Can be greatly changed, which is advantageous in achieving throttle-less (reducing pumping loss during small lift control and improving intake charging efficiency during large lift control).It is possible to simplify the configuration by reducing the number of parts of the variable valve operating device, which is advantageous for reducing the size and weight of the variable valve operating device, and for improving the reliability of the variable valve operating device.
[0031]
  According to the invention of claim 4,Claim 2 or claim 3InThe restriction link is pivotally connected to the control member by an axis parallel to the camshaft, and the connection point between the outer ring and the link mechanism is connected to the control member and the restriction as the eccentric ring rotates. Since the reciprocating arc motion is performed around the connection point with the link, the configuration of the restriction link is simplified.
[0032]
  Claim 5According to the invention which concerns on this, Claim 1Any one of Claim 4The control member rotates about an axis parallel to the camshaft, the connection point between the outer ring and the link mechanism is disposed above the camshaft, and the rotation shaft of the control member is connected to the connection Since it is arranged on the side of the point, the entire variable valve system does not become bulky, and it can be incorporated into an existing engine without increasing the overall height of the engine and without making major design changes. Will be advantageous.
[0033]
  Claim 6According to the invention according to claims 1 toClaim 5In any one of the above, since a direct-acting tappet is used, it is possible to incorporate an existing engine equipped with a direct-acting tappet without increasing the overall height of the engine and without making a major design change. Will be advantageous.
[0034]
DETAILED DESCRIPTION OF THE INVENTION
  Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0035]
Figure1 is the present inventionEmbodiment ofThe whole structure which applied the variable valve apparatus which concerns on this to the intake valve of an engine is shown. This engine employs a four-valve double overhead cam system having two intake valves 1 and 2 and two exhaust valves (not shown) in one cylinder. In the figure, 3 is a camshaft that rotates in synchronization with the crankshaft of the engine. Each of the intake valves 1 and 2 is driven by swing cams 4 and 5 that are swingably supported by the camshaft 3, and the valve lift amount and valve timing are changed according to the operating state of the engine.
[0036]
  In order to change the lift amount and timing of the intake valves 1 and 2, a plurality of eccentric rings 6 are integrally formed in the camshaft 3 at intervals in the axial direction, and an outer ring 7 is rotatably fitted to each eccentric ring 6. ing. The outer ring 7 and the swing cam 5 are connected by a single connecting link (link mechanism) 8. The swing cam 4 is supported on the camshaft 3 so as to swing integrally with the swing cam 5. A rotating shaft 11 is provided in parallel with the camshaft 3, and a plurality of control arms (control members) 12 are coupled to the rotating shaft 11 at intervals in the axial direction. Each control arm 12 and the outer ring 7 are connected by a regulation link 13 that regulates the displacement of the outer ring 7 accompanying the rotation of the eccentric ring 6 so that the swing cams 4 and 5 swing.
[0037]
  A worm gear 14 having teeth formed on only a part of the circumference is coupled to the rotating shaft 11. A worm 16 that is rotationally driven by a motor 15 meshes with the teeth of the worm gear 14. Then, the motor 15 is operated according to the operating state of the engine to rotate the control arm 12, and the position of the restriction link 13 is changed to change the lift amount and timing of the intake valves 1 and 2. It has become. In this case, the control arm 12 is controlled so that the valve lift amount increases as the engine load increases. Hereinafter, the variable valve operating device will be described in detail.
[0038]
  As shown in FIG. 2, a direct acting tappet 21 is provided at the upper end of the stem of the intake valve 2, and the swing cam 5 is in contact with the tappet 21. The intake valve 2 is urged in a direction to close the intake port 25 by a valve spring 24 provided between a retainer 22 provided in the tappet and a retainer 23 provided in the cylinder head. The intake valve 1 has the same configuration as the intake valve 2.
[0039]
  One end of the connection link 8 is rotatably connected to the swing cam 5 by a pin 31, and one end of the regulation link 13 is rotatably connected to the tip of the control arm 12 by a pin 32. Thus, the connecting link 8 and the regulation link 13 are linked with the outer ring 7 in the middle. In other words, the other end of each of the connection link 8 and the regulation link 13 is coaxially and rotatably connected by a connection pin 33 to a protruding portion formed by partially protruding the outer ring 7 outward. The pins 31 to 33 all extend in parallel with the camshaft 3.
[0040]
  A connection pin 33 between the outer ring 7 and the connection link 8 is disposed above the camshaft 3, and the rotation shaft 11 of the control arm 12 is disposed on the side of the connection point. The pin 32 at the tip of the control arm 12 is the rotation center of the restriction link 13. FIG. 2 in which the pin 32 is disposed below the rotation shaft 11 is in a large lift control state. As shown in FIG. 3, when the pin 32 is moved upward by the rotation of the control arm 12 and positioned above the camshaft 3, a small lift control state is established.
[0041]
  As shown in FIGS. 2 (a) and 2 (b), the position of the outer ring 7 changes with the rotation of the eccentric ring 6, and the swing cam 5 moves the direct acting tappet 21 as shown in FIG. 2 (a). The state in which the intake valve 2 is greatly lifted through (the swing cam 4 has lifted the intake valve 1 through the direct acting tappet), and the intake valve 2 (intake air) as shown in FIG. It swings between the lift amount of the valve 1) and zero. The same applies to the case of FIG. 3 which is the small lift control state (see FIGS. 3A and 3B).
[0042]
  FIG. 4 specifically shows the operation of the variable valve operating apparatus. The control arm 12, the connection link 8, and the restriction link 13 are represented by straight lines. C is a rotation locus of the center of the eccentric ring 6. Further, the relationship between the intake valve 1 and the swing cam 4 is the same as the relationship between the intake valve 2 and the swing cam 5, and the swing cam 4 works in the same manner as the swing cam 5. The variable valve operating apparatus will be described with reference to the relationship between the rocking cam 2 and the swing cam 5.
[0043]
  First, on the peripheral surface of the swing cam 5, a base circle surface (base circle section) θ1 whose curvature radius is constant within a predetermined angle range, and a cam surface whose curvature radius gradually increases following θ1 ( Lift section) θ2. The rotation direction of the camshaft 3 (eccentric ring 6) is set to the clockwise direction (clockwise) in FIG. The state shown by the solid line in FIG. 4 is a valve lift peak time when the control arm 12 is in the large lift control position and the connecting pin 33 of the outer ring 7 is positioned at the uppermost position. At this time, the swing cam 5 is provided so that the cam nose side end of the cam surface θ <b> 2 is in contact with the tappet 21.
[0044]
  In the state of the solid line in FIG. 4, when the eccentric ring 6 rotates, the outer ring 7 is displaced accordingly, but the displacement is regulated by the regulation link 13. That is, since the restricting link 13 rotates around the pin 32 disposed below the rotating shaft 11, the connecting pin 33 of the outer ring 7 reciprocates around the pin 32 every time the eccentric ring 6 makes one rotation. An arc motion A is performed (the restriction link 13 reciprocates between a solid line state and a broken line state).
[0045]
  The direction of the reciprocating arc motion A is substantially the same as the swinging direction of the connecting point (pin 31) between the swing cam 5 and the connecting link 8. That is, the direction of the string connecting both ends of the reciprocating arc motion A of the connecting pin 33 (the solid connecting pin 33 and the broken connecting pin 33) (hereinafter, this direction is referred to as the direction of the reciprocating arc motion A) and swinging. The direction of the string connecting both swing ends of the connection pin 31 of the cam 5 (the solid connection pin 31 and the broken connection pin 31) (hereinafter, this direction is referred to as the swing direction of the swing cam 5). The angle is small (30 degrees or less).
[0046]
  Along with the reciprocating arc motion A of the connecting pin 33, the swing cam 5 connected to the outer ring 7 by the connection link 8 swings between a solid line state and a broken line state. In the broken line state, the rocking cam 5 has its base circle surface θ1 in contact with the tappet 21, and the valve lift is zero (the intake valves 1 and 2 are closed).
[0047]
  The lift characteristics of the intake valves 1 and 2 when the swing cam 5 swings between the solid line state and the broken line state in FIG. 4 are indicated by L1 in FIG.
[0048]
  Next, the control arm 12 is rotated upward around the rotation shaft 11 from the state indicated by the solid line in FIG. 4, and the pin 32, which is the rotation center of the restriction link 13, rotates the camshaft 3 more than during the large lift control. When a substantially horizontal state indicated by a one-dot chain line positioned on the front side in the direction is set, a small lift control state is set. That is, when the eccentric ring 6 rotates, the displacement of the connecting pin 33 of the outer ring 7 is restricted by the restricting link 13 and performs a reciprocating arc motion B around the pin 32 disposed on the side of the rotating shaft 11. (The restriction link 13 reciprocates between the one-dot chain line state and the two-dot chain line state).
[0049]
  The position of the reciprocating arc motion B during the small lift control is positioned closer to the camshaft 3 in the rotational direction than the position of the reciprocating arc motion A during the large lift control. The direction of the reciprocating arc motion B (the direction of the string connecting the connecting pin 33 of the one-dot chain line and the connecting pin 33 of the two-dot chain line) and the direction of the reciprocating arc motion A is an angle of about 45 degrees or more and 90 degrees or less. Intersect with each other. Therefore, the direction of the reciprocating arc motion B is transverse to the swing direction of the swing cam 5. That is, the angle formed between the direction of the reciprocating arc motion B and the swinging direction of the swing cam 5 is larger than that in the case of the large lift control (45 degrees or more and 120 degrees or less).
[0050]
  Along with the reciprocating arc motion B of the connecting pin 33, the swing cam 5 connected to the outer ring 7 by the connecting link 8 swings between a one-dot chain line state and a broken line state. In the case of this example, the position when the connecting pin 33 becomes zero in the valve lift amount by the reciprocating arc motion B (two-dot chain line position) is the position when the valve lift amount becomes zero by the reciprocating arc motion A ( The position of the swing cam 5 when the connecting pin 33 is positioned at the two-dot chain line position by the reciprocating arc motion B is substituted with the broken line state.
[0051]
  The lift characteristics of the intake valves 1 and 2 when the swing cam 5 swings between the one-dot chain line state and the broken line state in FIG. 4 are indicated by L2 in FIG.
[0052]
  Thus, when shifting from the large lift control to the small lift control as described above, the pin 32 which is the rotation center of the restricting link 13 is moved by the rotation of the control arm 12, and the reciprocating arc of the connecting pin 33. The position of the movement is moved from A to B, that is, to the front side in the rotational direction of the camshaft 3. As a result, the center of the eccentric wheel 6 at the valve lift peak is positioned at C1 during the large lift control, but the center of the eccentric wheel 6 at the valve lift peak moves to C2 during the small lift. That is, when shifting from the time of the large lift control to the time of the small lift control, the valve angle is advanced by the center angle α related to C1 and C2.
[0053]
  As described above, when the valve lift amount is decreased, the valve lift peak angle is advanced. As shown in FIG. 5, the opening start timing of the intake valves 1 and 2 regardless of the valve lift amount. It is advantageous to substantially align
[0054]
  Next, looking at the lift / down speed of the intake valve 2, the center of the eccentric wheel 6 when the swing cam 5 is positioned at the swing end of the valve lift amount zero side during the large lift control and the small lift control is as follows. It is in C3 of FIG.
[0055]
  When the center of the eccentric wheel 6 rotates clockwise from the point C3 around the axis of the camshaft 3, in the case of large lift control, the center of the eccentric wheel 6 moves from the point C3 to a rotation angle of 60 degrees. Since the direction is transverse to the direction of the reciprocating arc motion A of the connecting pin 33, the connecting pin 33 hardly rises from the rocking end on the broken line side. Therefore, the swing cam 5 hardly moves.
[0056]
  Since the rotational movement direction of the center of the eccentric ring 6 is in the direction of the reciprocating arc motion A from the time when the rotation angle of 60 degrees is passed, the connecting pin 33 is compared with the rotational movement of the center of the eccentric ring 6. Ascending quickly. Since the direction of the reciprocating arc motion A and the swinging direction of the swing cam 5 are substantially the same, the swing cam 5 starts to swing substantially as the connecting pin 33 is lifted. Then, when the center of the eccentric ring 6 reaches a rotation angle exceeding 90 degrees from the point C3, the cam surface (lift section) θ2 of the swing cam 5 comes into contact with the tappet 21 and the intake valve 2 Begins to open.
[0057]
  On the other hand, in the case of the small lift control, the moving direction when the center of the eccentric ring 6 rotates from the point C3 is relatively close to the direction of the reciprocating arc motion B. 33 rises relatively faster than in the case of large lift control. However, since the crossing angle between the direction of the reciprocating arc motion B and the swinging direction of the swing cam 5 is large, even if the connecting pin 33 starts to rise in the reciprocating arc motion B, the swing cam 5 is almost swung. First, the intake valve 2 starts to open when the center of the eccentric wheel 6 reaches a rotation angle of about 90 to 120 degrees from C3.
[0058]
  That is, in the control of the valve lift amount, the reciprocal arc movement position of the connecting pin 33 is moved forward in the rotational direction of the camshaft 3 to advance the valve lift peak as the lift amount becomes smaller. In addition, since the angle formed by the reciprocating arc motion direction and the swing direction of the swing cam 5 is increased, it is further advantageous to substantially align the opening timing of the intake valve 2. Yes.
[0059]
  Further, in this example, as the valve lift amount increases, the rotation center of the restriction link 13 (the connection pin 32) is brought closer to the axial center side of the camshaft 3, and the string of the reciprocating arc motion of the connection pin 33 is It faces the 3 axis side. Therefore, when the center of the eccentric wheel 6 rotates clockwise from the point C1, the lowering speed of the connecting pin 33 is increased, and as a result, the intake valve 2 is closed early. That is, the intake valve 2 can be quickly closed, which is advantageous for reducing pumping loss.
[0060]
  Thus, since the connecting link 8 and the regulating link 13 link the outer ring 7 in the middle, the position of the regulating link 13 is greatly changed by the control arm 12 and the valve lift amount by the swing cam 5 is greatly changed. Since it is possible to obtain an optimum intake amount corresponding to the engine operating state only by controlling the valve lift amount, it is possible to reduce pumping loss as a throttleless and intake air during large lift control. Filling efficiency can be improved.
[0061]
  In the above embodiment, since the swing cam 5 and the outer ring 7 are connected by the single link 8 and one end of each of the link 8 and the restriction link 13 is connected to the outer ring 7, the number of parts is reduced. Thus, the configuration can be simplified, which is advantageous for making the variable valve operating apparatus compact and lightweight. In addition, since the pivot shaft 11 of the control arm 12 is disposed on the side of the connecting pin of the outer ring 7, the entire variable valve device is not bulky, and is particularly of a direct acting tappet type with respect to an existing engine. This is advantageous in incorporating the engine while suppressing an increase in the overall height of the engine and without making a major design change.
[0062]
  The connection link 8 and the restriction link 13 can be connected to the outer ring 7 at different positions with separate pins.
[0063]
  <Reference form>
  FIG.Reference form (not an embodiment of the present invention)The whole structure of the variable valve operating apparatus of the intake valve which concerns on is shown.EmbodimentSimilarly, this engine employs a four-valve double overhead cam system having two intake valves 1 and 2 and two exhaust valves (not shown) in one cylinder. In the figure, 3 is a camshaft that rotates in synchronization with the crankshaft of the engine. Each of the intake valves 1 and 2 is driven by swing cams 4 and 5 that are swingably supported by the camshaft 3, and the valve lift amount and valve timing are changed according to the operating state of the engine.
[0064]
  In order to change the lift amount and timing of the intake valves 1 and 2, a plurality of eccentric wheels 6 are provided on the camshaft 3 so as to rotate integrally with the camshaft 3 at intervals in the axial direction. The outer ring 7 is rotatably fitted to each eccentric ring 6. The outer ring 7 and the swing cam 5 are connected by a link mechanism. The swing cam 4 is supported on the camshaft 3 so as to swing integrally with the swing cam 5. The link mechanism includes a first link 9 connected to the swing cam 5 and a second link 10 connected to the outer ring 7, and the first link 9 and the second link 10 are rotatably connected. Has been.
[0065]
  A rotating shaft 11 is provided in parallel with the camshaft 3, and a plurality of control arms (control members) 12 are coupled to the rotating shaft 11 at intervals in the axial direction. Each control arm 12 and the outer ring 7 are connected using the second link 10. That is, the second link 10 extends further to the opposite side of the first link 9 than the connection point with the outer ring 7 and is connected to the control arm 12. The extension portion of the second link 10 forms a restricting link 13 that restricts the displacement of the outer ring 7 accompanying the rotation of the eccentric ring 6 so that the swing cam 5 swings.
[0066]
  A worm gear 14 is coupled to the rotating shaft 11. A worm 16 that is rotationally driven by a motor 15 meshes with the teeth of the worm gear 14. Then, the motor 15 is operated according to the operating state of the engine to rotate the control arm 12, and the position of the restriction link 13 is changed to change the lift amount and timing of the intake valves 1 and 2. It has become. In this case, the control arm 12 is controlled so that the valve lift amount increases as the engine load increases. Hereinafter, the variable valve operating device will be described in detail.
[0067]
  As shown in FIG. 7, a direct acting tappet 21 is provided at the upper end of the stem of the intake valve 2, and the swing cam 5 is in contact with the tappet 21. The intake valve 2 is urged in a direction to close the intake port 25 by a valve spring 24 provided between a retainer 22 provided in the tappet and a retainer 23 provided in the cylinder head. The intake valve 1 has the same configuration as the intake valve 2.
[0068]
  One end of the first link 9 is rotatably connected to the swing cam 5 by a pin 31 and the other end is rotatably connected to one end of the second link 10 by a pin 30. The second link 10 is connected by a connecting pin 33 to a projecting portion having an intermediate portion projecting a part of the outer ring 7 outward. The other end of the second link 10, that is, the base end of the restriction link 13 is rotatably connected to the tip of the control arm 12 by a pin 32. Therefore, the link mechanism and the regulation link 13 are linked with the outer ring 7 in the middle. Each of the pins 30 to 33 extends in parallel with the camshaft 3.
[0069]
  A connecting pin 33 between the outer ring 7 and the second link 10 is disposed above the camshaft 3, and the rotating shaft 11 of the control arm 12 is disposed on the side of the connecting pin 33. The pin 32 at the tip of the control arm 12 is the rotation center of the second link 10 (regulation link 13). FIG. 7 in which the pin 32 is arranged at a high position (a position relatively above the axial center position of the camshaft 3) is in a large lift control state. As shown in FIG. 8, when the pin 32 is moved downward by the rotation of the control arm 12 and positioned at a low position (a lateral position of the axis of the camshaft 3), a small lift control state is established.
[0070]
  As shown in FIGS. 7 (a) and 7 (b), the position of the outer ring 7 changes as the eccentric ring 6 rotates, and the swing cam 5 moves the direct acting tappet 21 as shown in FIG. 7 (a). The state in which the intake valve 2 is greatly lifted through (the swing cam 4 has lifted the intake valve 1 through the direct acting tappet), and the intake valve 2 (intake air) as shown in FIG. It swings between the lift amount of the valve 1) and zero. The same applies to the case of FIG. 8 in the small lift control state (see FIGS. 8A and 8B).
[0071]
  FIG. 9 specifically shows the operation of the variable valve operating apparatus. The control arm 12, the first link 9, and the second link 10 (restriction link 13) are represented by straight lines. C is a rotation locus of the center of the eccentric ring 6. Further, the relationship between the intake valve 1 and the swing cam 4 is the same as the relationship between the intake valve 2 and the swing cam 5, and the swing cam 4 works in the same manner as the swing cam 5. The variable valve operating apparatus will be described with reference to the relationship between the rocking cam 2 and the swing cam 5.
[0072]
  First, on the peripheral surface of the swing cam 5, a base circle surface (base circle section) θ1 whose curvature radius is constant within a predetermined angle range, and a cam surface whose curvature radius gradually increases following θ1 ( Lift section) θ2. The rotation direction of the camshaft 3 (eccentric ring 6) is set in the clockwise direction (clockwise) in FIG. The state shown by the solid line in FIG. 9 is a valve lift peak time when the control arm 12 is in the large lift control position and the connecting pin 33 of the outer ring 7 is positioned at the lowest position. At this time, the swing cam 5 is set so that the cam nose side end of the cam surface θ2 is in contact with the tappet 21.
[0073]
  In the solid line state of FIG. 9, when the eccentric ring 6 rotates, the outer ring 7 is displaced accordingly, but the displacement is regulated by the regulation link 13. That is, since the restriction link 13 rotates about the pin 32, the connecting pin 33 of the outer ring 7 performs a reciprocating arc motion A about the pin 32 every time the eccentric ring 6 makes one rotation (restriction). The link 13 reciprocates between a solid line state and a broken line state).
[0074]
  Along with the reciprocating arc motion A of the connecting pin 33, the swing cam 5 connected to the outer ring 7 by the first and second links 9 and 10 swings between the solid line state and the broken line state. . In the broken line state, the rocking cam 5 has its base circle surface θ1 in contact with the tappet 21, and the valve lift is zero (the intake valves 1 and 2 are closed).
[0075]
  Next, the control arm 12 is rotated downward from the state indicated by the solid line in FIG. 9 around the rotation shaft 11 so that the pin 32 which is the rotation center of the restriction link 13 is rotated in the direction of rotation of the camshaft 3 rather than during the large lift control. When positioned on the near side, a small lift control state is established. In other words, when the eccentric ring 6 rotates, the displacement of the connecting pin 33 of the outer ring 7 is restricted by the restricting link 13 and performs a reciprocating arc motion B around the pin 32 disposed below the rotating shaft 11. (The restriction link 13 reciprocates between the one-dot chain line state and the two-dot chain line state).
[0076]
  The position of the reciprocating arc motion B during the small lift control is positioned closer to the camshaft 3 in the rotational direction than the position of the reciprocating arc motion A during the large lift control.
[0077]
  Along with the reciprocating arc motion B of the connecting pin 33, the swing cam 5 connected to the outer ring 7 by the connecting link 8 swings between the one-dot chain line state and the two-dot chain line state.
[0078]
  As described above, when shifting from the large lift control to the small lift control, the position of the reciprocating arc movement of the connecting pin 33 moves to the front side in the rotational direction of the camshaft 3, so the center of the eccentric ring 6 at the valve lift peak is Move from C1 to C2. That is, when shifting from the time of the large lift control to the time of the small lift control, the valve angle is advanced by the center angle α related to C1 and C2.
[0079]
  In this way, if the valve lift amount is reduced, the peak time of the valve lift is advanced, which is advantageous in substantially aligning the valve opening start timings of the intake valves 1 and 2 regardless of the valve lift amount. Become.
[0080]
  Thus, since the connecting link 8 and the regulating link 13 link the outer ring 7 in the middle, the position of the regulating link 13 is greatly changed by the control arm 12 and the valve lift amount by the swing cam 5 is greatly changed. Since it is possible to obtain an optimum intake amount corresponding to the engine operating state only by controlling the valve lift amount, it is possible to reduce pumping loss as a throttleless and intake air during large lift control. Filling efficiency can be improved.
[0081]
  In the reference embodiment, the swing cam 5 and the outer ring 7 are connected by the two links 9 and 10 and a part of the second link 10 is the restriction link 13, so that the number of parts is reduced. Thus, the configuration can be simplified, which is advantageous for making the variable valve operating apparatus compact and lightweight. In addition, since the pivot shaft 11 of the control arm 12 is disposed on the side of the connecting pin of the outer ring 7, the entire variable valve device is not bulky, and is particularly of a direct acting tappet type with respect to an existing engine. This is advantageous in incorporating the engine while suppressing an increase in the overall height of the engine and without making a major design change.
[0082]
  The connection pin 32 between the control arm 12 and the second link 10 (the restriction link 13) and the connection pin 31 between the swing cam 5 and the first link 9 are the connection pins between the second link 10 and the outer ring 7. They move in opposite directions with 33 as a fulcrum. In other words, since the control arm 12 and the swing cam 5 are in a relation of moving in the opposite directions as the seesaw as the second link 10, the control arm 12 swings when the control arm 12 is moved according to the operating state of the engine. The component force acting on the cam 5 in the swinging direction is increased, and the load acting on the connecting pins 30 to 33 is decreased accordingly. Therefore, the driving force required for changing the valve lift amount can be reduced, and the movements of the links 9 and 10 and the control arm 12 are smoothed, and the reliability of the variable valve operating apparatus is increased.
[0083]
  The aboveEmbodiment and reference formIn the above, the control member (arm 12) pivots the rotation center of the base end of the restriction link. However, the control member may move the rotation center of the restriction link linearly.
[0084]
  Also, aboveEmbodiment and reference formIn this case, the restricting link restricts the displacement of the outer ring so that the connecting point between the outer ring and the link mechanism performs a reciprocating arc motion. However, the restricting link moves the connecting point, for example, in an elliptical circular path. It may restrict the displacement of the outer ring.
[0085]
  Also, aboveEmbodiment and reference formIs related to the variable valve system of the intake valve,They areVariable valve operating device for exhaust valveAsIt can also be adopted.
[Brief description of the drawings]
FIG. 1 of the present inventionEmbodimentThe perspective view which shows the variable valve gear concerning this.
FIG. 2 is a cross-sectional view showing states of a valve lift peak (a) and a lift amount zero (b) at the time of large lift control of the apparatus.
FIG. 3 is a cross-sectional view showing states of a valve lift peak (a) and a lift amount zero (b) during small lift control of the apparatus.
FIG. 4 is an explanatory diagram of the operation of the apparatus.
FIG. 5 is a graph showing valve lift characteristics of the apparatus.
[Fig. 6]Reference formThe perspective view which shows the variable valve gear concerning this.
FIG. 7 is a cross-sectional view showing states of a valve lift peak (a) and a lift amount zero (b) at the time of large lift control of the apparatus.
FIG. 8 is a cross-sectional view showing states of a valve lift peak (a) and a lift amount zero (b) at the time of small lift control of the apparatus.
FIG. 9 is an explanatory diagram of the operation of the apparatus.
[Explanation of symbols]
      1, 2, intake valve
          3 Camshaft
      4,5 Swing cam
          6 Eccentric ring
          7 outer ring
          8 Link (link mechanism)
          9 First link
        10 Second link
        11 Rotating shaft
        12 Control arm
        13 Regulatory links
        21 Tappet
  30-33 connecting pin

Claims (6)

A camshaft having an eccentric wheel that rotates in synchronization with the crankshaft of the engine;
A swing cam that lifts the valve provided to swing about the camshaft;
An outer ring rotatably fitted on the eccentric ring,
A link mechanism for connecting the swing cam and the outer ring, and transmitting a displacement of the outer ring to the swing cam;
A regulation link connected to the outer ring and regulating the displacement of the outer ring accompanying the rotation of the eccentric ring so that the swing cam swings via the link mechanism;
Bei example a control member in accordance with the operating condition of the engine changes the position of the regulating link,
The control of the valve lift so that the lift amount of the valve by the swing cam changes, and the peak of the valve lift appears at the rotation angle closer to the camshaft rotation direction than at the time of large lift control at the time of small lift control. A variable valve operating apparatus for an engine that changes the position of the restriction link by a member ,
The outer ring is disposed between the link mechanism and the restriction link in the axial direction of the camshaft,
The restricting link is rotatably provided about an axis parallel to the camshaft and is connected to the outer ring, and the connection point between the outer ring and the link mechanism moves in a reciprocating arc motion as the eccentric wheel rotates. Restricting the displacement of the outer ring to
The control member may change the position of the rotation shaft of the restriction link so that the reciprocating arc movement position of the connection point is displaced in the circumferential direction around the axis of the camshaft. Variable valve device. In claim 1,
The link mechanism includes a single link that connects the swing cam and the outer ring, and one end of each of the link and the restriction link is rotatably connected to the outer ring. Variable valve operating device for the engine. A camshaft having an eccentric wheel that rotates in synchronization with the crankshaft of the engine;
A swing cam that lifts the valve provided to swing about the camshaft;
An outer ring rotatably fitted on the eccentric ring,
A link mechanism for connecting the swing cam and the outer ring, and transmitting a displacement of the outer ring to the swing cam;
A regulation link connected to the outer ring and regulating the displacement of the outer ring accompanying the rotation of the eccentric ring so that the swing cam swings via the link mechanism;
A control member that changes the position of the restriction link according to the operating state of the engine,
The control of the valve lift so that the lift amount of the valve by the swing cam changes, and the peak of the valve lift appears at the rotation angle closer to the camshaft rotation direction than at the time of large lift control at the time of small lift control. A variable valve operating apparatus for an engine that changes the position of the restriction link by a member,
The outer ring is disposed between the link mechanism and the restriction link in the axial direction of the camshaft,
The link mechanism includes a single link that connects the swing cam and the outer ring, and one end of each of the link and the restriction link is rotatably connected to the outer ring. Variable valve operating device for the engine. In claim 2 or claim 3,
The restriction link is pivotally connected to the control member by an axis parallel to the camshaft, and a connection point between the outer ring and the link mechanism is connected to the control member and the link with the rotation of the eccentric ring. A variable valve operating device for an engine, which reciprocates circularly around a connection point with a restriction link . In any one of Claims 1 thru | or 4 ,
The control member rotates around an axis parallel to the camshaft.
The connection point between the outer ring and the link mechanism is disposed above the camshaft,
A variable valve operating apparatus for an engine, wherein a rotation shaft of the control member is disposed on a side of the connection point. In any one of Claims 1 thru | or 5 ,
The variable valve operating apparatus for an engine, wherein the swing cam is in contact with a direct acting tappet.

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