JP4269924B2 - Valve lift amount adjusting method and adjusting mechanism for internal combustion engine - Google Patents

Description

  The present invention relates to a valve lift amount of an internal combustion engine that swings a rocker arm with rotation of a camshaft and swings a swing cam provided on the camshaft via a link member at an end of the rocker arm to open and close a valve. The present invention relates to an adjustment method and an adjustment mechanism.

  Conventionally, for example, Patent Document 1 described below describes a valve operating mechanism that variably controls a valve lift amount in accordance with a change in an engine operating state in order to improve engine performance.

This is because the swing cam opens and closes the intake valve by the rotational force transmitted from the drive cam, which is an eccentric rotating cam provided on the camshaft, via the rocker arm, link member, etc., and the control is arranged parallel to the camshaft. The control cam on the outer circumference of the shaft is rotationally controlled to change the rocking fulcrum of the rocker arm, thereby making the valve lift variable according to the operating state.
JP 2002-256832 A

  By the way, in the conventional valve operating mechanism described above, the valve lift amount is determined by the dimensional accuracy of a plurality of link parts, and therefore the valve lift amount varies depending on the dimensional accuracy. And the adjustment work to make this valve lift amount appropriate is to measure the valve lift amount with the valve mechanism assembled, and then disassemble and then replace the link member to be adjusted with a different length. It is necessary, and the workability is deteriorated.

  Therefore, an object of the present invention is to make it possible to easily adjust the valve lift amount.

The present invention is, to oscillate the rocker arm in accordance with the rotation of the camshaft, this end of the rocker arm via the link member to swing the swing cam provided on the cam shaft by opening and closing the valve, before Symbol rocker arm wherein the link member, and connected by a connecting shaft, the valve lift amount measuring, by changing the position for connecting the said rocker arm of the connecting shaft and the link member, the internal combustion engine for adjusting the valve lift valve In the lift amount adjusting method, the connecting shaft includes a pin portion that rotatably supports one of the end portions of the rocker arm and the link member, and a guide portion integrated with the pin portion. A moving guide part for moving the rocker arm is provided on the other of the rocker arm and the link member, and the guide part together with the pin part in the radial direction of the pin part After moving along the movement guide part by the adjusting means to change the position of the connecting shaft, the wedge-shaped member is inserted from the direction intersecting the movement guide part, and the inclined surface provided on the wedge-shaped member is The most important feature is that the connecting shaft is fixed by being brought into sliding contact with an inclined surface provided in the guide portion so as to be pressed from a direction opposite to the pressing direction by the adjusting means .

  According to the present invention, the rocker arm and the link member are connected by the connecting shaft, and the valve lift amount is adjusted by changing the position of connecting the rocker arm and the link member of the connecting shaft. Therefore, the valve lift amount can be adjusted without adjusting the valve lift amount.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a perspective view of a valve operating mechanism having a valve lift adjustment mechanism for an internal combustion engine according to an embodiment of the present invention, and FIG. 2 is a side view thereof. The valve operating mechanism here is applied to the intake side, and is provided with two intake valves 1 per cylinder and a variable mechanism that makes the valve lift amount of each intake valve 1 variable according to the engine operating state. I have.

  That is, this variable valve mechanism is slidably provided on a cylinder head (not shown) via a valve guide, and a pair of intake valves 1 as valves energized in the closing direction by the spring force of a valve spring; A drive shaft 3 as a hollow cam shaft rotatably supported by a bearing (not shown) at the top of the cylinder head, one drive cam 5 which is an eccentric rotation cam fixed to the drive shaft 3, A swing cam 7 that is swingably supported on the outer periphery and is in sliding contact with the upper surface 6 a of the valve lifter 6 disposed at the upper end of each intake valve 1, and is linked between the drive cam 5 and the swing cam 7. The transmission mechanism 8 that transmits the rotational force of the drive cam 5 as the swinging force of the swing cam 7 and the control mechanism 9 that controls the operating position of the transmission mechanism 8 are provided.

  The drive shaft 3 is arranged along the longitudinal direction of the engine and is rotated from the crankshaft of the engine via a driven sprocket (not shown) provided at one end or a timing chain wound around the driven sprocket. The force is transmitted, and the direction of rotation is set in the clockwise direction in FIG.

  The drive cam 5 is formed in a substantially annular shape by a wear-resistant material, has a cylindrical portion 5a integrally provided at the outer end, and has a drive shaft insertion hole penetratingly formed in the internal axis direction. As shown, the center Y is offset from the axis X of the drive shaft 3 by a predetermined amount β in the radial direction. The cylindrical portion 5a of the drive cam 5 is connected and fixed to the drive shaft 3 by a connection pin (not shown) inserted through the drive shaft 3 from the diameter direction. Further, the drive cam 5 rotates in the clockwise direction (arrow direction) in FIG. 2 as the drive shaft 3 rotates.

  The valve lifter 6 is formed in a cylindrical shape with a lid, and is slidably held in a holding hole of the cylinder head, and an upper surface 6a of a swing cam 7 on which a cam body 7a (described later) comes into sliding contact is formed in a flat shape. ing.

  The rocking cam 7 includes a pair of substantially raindrop-shaped cam bodies 7 a integrally provided at both ends of a substantially cylindrical base end portion 10, and a support hole 10 a formed in the inner axial direction of the base end portion 10. Is entirely supported by the drive shaft 3 inserted therethrough, and a pin hole 11a is formed through a cam nose portion 11 on one end side of one of the two swing cams 7. In addition, the cam surface formed on the lower surface of each cam body 7a comes into contact with a predetermined position of the upper surface 6a of each valve lifter 6 according to the swing position of the swing cam 7, thereby changing the valve lift characteristics.

  The transmission mechanism 8 includes a rocker arm 13 disposed above the drive shaft 3, a link arm 14 connecting the one end 13 a of the rocker arm 13 and the drive cam 5, the other end 13 b of the rocker arm 13, and the swing cam 7. And a link member 15 for connecting the two.

  The rocker arm 13 is rotatably supported by a control cam 23 (to be described later) via a support hole 13d. Further, one end 13a projecting from one end outer side of the cylindrical base 13c penetrates and forms a pin hole into which the pin 16 is fitted, while the other end 13b projecting from the other end outer side of the cylindrical base 13c. The pin fixing part 18 in which the pin member 17 as a connection shaft connected with the link member 15 is provided is formed.

  The details of the pin fixing portion 18 described above are shown in FIG. The pin member 17 includes a pin portion 17a that rotatably supports the link member 15, and a guide portion 17b that is integral with the pin portion 17a. The guide portion 17b is movable in the vertical direction in a guide hole 19 as a movement guide portion formed in the other end portion 13b of the rocker arm 13 from the lower side to the upper side in FIG.

  A screw hole 20 is provided in the other end portion 13b of the upper portion of the guide hole 19, an adjustment screw 21 as an adjusting means is screwed into the screw hole 20 from the outside of the other end portion 13b, and the tip of the adjustment screw 21 is brought into contact with the guide portion 17b. ing. That is, by screwing the adjusting screw 21, the guide portion 17b can be moved downward, and the connection position between the rocker arm 13 and the link member 15 can be changed in the radial direction of the pin portion 17a. The adjusting screw 21 is provided with a nut 22 for preventing loosening.

  The guide hole 19 is provided so as to intersect the fixing hole 24 from the left end of the other end portion 13 b in FIG. 3, and a wedge-shaped member 25 as a fixing means is inserted into the fixing hole 24. In FIG. 3, the wedge-shaped member 25 has an upper surface formed as a downwardly inclined surface 25a, and a lower surface of the guide portion 17b facing the inclined surface 25b is formed as a similar downwardly inclined surface 17c.

  A screw hole 26 is formed on the left opening side of the fixing hole 24 in FIG. 3, a fixing screw 27 is screwed into the screw hole 26, and the tip of the fixing screw 27 is brought into contact with the wedge-shaped member 25. That is, by screwing the fixing screw 27, the inclined surface 25a of the wedge-shaped member 25 is brought into contact with the inclined surface 17c of the guide portion 17b to fix the pin member 17. The fixing screw 27 is provided with a nut 28 for preventing loosening.

  FIG. 4 shows another example of the pin fixing portion 18 described above. In contrast to FIG. 3, the inclined surface 25a of the wedge-shaped member 25 is lowered to the left in FIG. 4, and the inclined surface 17c of the guide portion 17b is also lowered to the left correspondingly.

  A fixing screw 29 is screwed into the end portion of the wedge-shaped member 25. Therefore, in this case, by rotating the fixing screw 29 in the pulling direction, the inclined surface 25a of the wedge-shaped member 25 is brought into contact with the inclined surface 17c of the guide portion 17b and the pin member 17 is fixed.

  The link arm 14 shown in FIG. 1 and FIG. 2 is a base end portion 14a that is a relatively large-diameter annular end portion, and the other end portion that projects from a predetermined position on the outer peripheral surface of the base end portion 14a. A projecting end 14b, and at the central position of the base end portion 14a, a fitting hole 14c is formed to be rotatably fitted to the outer peripheral surface of the drive cam 5. On the projecting end 14b, the pin 16 is provided. A pin hole that is rotatably inserted is formed. The axis 16 a of the pin 16 is a pivot point with the one end 13 a of the rocker arm 13.

  Further, the link member 15 is formed in a substantially U-shaped cross section, and the bifurcated end portions 15a and 15b respectively connect the other end portion 13b of the rocker arm 13 and the cam nose portion 11 of one cam body 7a. While being sandwiched, the pin portion 17a and the pin 30 are rotatably connected to the other end portion 13b and the cam nose portion 11, respectively.

  In addition, a snap ring (not shown) that restricts the movement of the link member 15 in the axial direction is provided at one end portion of the pin 30, and the pin portions 17 a and the shaft centers 17 d and 30 a of the pin 30 are provided at both end portions of the link member 15. 15a, 15b, the other end portion 13b of the rocker arm 13, and the cam nose portion 11 of the swing cam 7.

  As shown in FIG. 1, the control mechanism 9 includes a control shaft 32 that is rotatably supported by a bearing (not shown) at a position above the drive shaft 3, and an outer periphery of the control shaft 32. The control cam 23 serving as a swing fulcrum, a DC motor 36 for controlling the rotation of the control shaft 32 via a ball screw mechanism 34 and a gear mechanism 35, and a controller 37 for controlling the driving of the DC motor 36 are provided. Yes.

The control shaft 32 is disposed in the longitudinal direction of the engine in parallel with the drive shaft 3, while the control cam 23 has a cylindrical shape, and the position of the shaft center P2 is as much as the thick portion 23a as shown in FIG. The control shaft 32 is deviated from the axis P1 by α.

  The ball screw mechanism 34 is disposed in a direction perpendicular to the control shaft 32 between a pair of levers 39a and 39b projecting from a cylindrical portion 39 fixed to one end of the control shaft 32, and between the tip portions of both levers 39a and 39b. The cylindrical nut member 41 is rotatably provided via a pin 40, and a screw shaft 42 that is screwed into a female screw formed on the inner peripheral surface of the nut member 41.

  The gear mechanism 35 is coupled to the distal end portion of the drive shaft 36a of the DC motor 36 and the distal end portion of the screw shaft 42, and the two bevel gears 35a and 35b are engaged with each other from the direction perpendicular to the axis. Consists of.

  The controller 37 detects the current engine operating state by calculation based on detection signals from various sensors such as a crank angle sensor, an air flow meter, a water temperature sensor, a throttle opening sensor, and the like. A control signal is output to the DC motor 36 based on a detection signal from a potentiometer 38 that detects the rotational position.

  According to the valve mechanism described above, at the time of engine low speed and low load, the DC motor 36 is rotated by a control signal from the controller 37, and the control shaft 32 is counterclockwise in FIG. 2 via the gear mechanism 35 and the ball core mechanism 34. Maximum rotation in the rotation direction. Therefore, the control cam 23 moves the shaft center P2 to the rotation angle position on the lower right in FIG. 2 with respect to the shaft center P1 of the control shaft 32. That is, the thick portion 23a moves from the drive shaft 3 side to the pivot point 16a side. Therefore, the entire rocker arm 13 rotates in the clockwise direction from the state of FIG. 2, and accordingly, each cam body 7 a is forcibly pulled up on the cam nose portion 11 side via the link member 15, and the whole is rotated clockwise. Rotate in the direction.

  Therefore, when the drive cam 5 rotates and pushes up the one end portion 13a of the rocker arm 13 via the link arm 14 during the opening / closing operation of the intake valve 1 in this state, the lift amount is increased by the swing cam via the link member 15. 7 and the valve lifter 6, but the lift amount is sufficiently small.

  Next, adjustment of the valve lift amount in the above-described valve operating mechanism will be described. In the state shown in FIG. 3, the leading ends of the adjusting screw 21 and the fixing screw 27 press the guide portion 17b and the wedge-shaped member 25, and the inclined surfaces 17c and 25a are in close contact with each other. Further, the adjusting screw 21 and the fixing screw 27 are prevented from being loosened by the loosening prevention nuts 22 and 28, respectively, so that the rocker arm 13 and the link member 15 are connected via the pin member 17.

  Here, when variations occur in the valve lift amount and adjustment is necessary, for example, after loosening the locking nut 22, the adjusting screw 21 is rotated in the direction of pulling out, and the locking nut 28 is further loosened. Then, the fixing screw 27 is rotated in the pushing direction. Then, the wedge-shaped member 25 is pushed forward by the fixing screw 27, and accordingly, the inclined surface 25a is in sliding contact with the inclined surface 17c of the guide portion 17b, and the guide portion 17b is moved upward by the retraction of the adjusting screw 21. Push up.

Thereby, the pin portion 17a integrated with the guide portion 17b and the guide portion 17b , that is, the pin member 17 moves upward, and the link member 15 shown in FIG. 2 connected to the pin portion 17a also rises. As the link member 15 moves up, the swing cam 7 connected to the link member 15 rotates in the clockwise direction in FIG. After the adjustment, the locking nuts 22 and 28 are fastened, and the locking screw 21 and the fixing screw 27 are locked.

  On the contrary, when adjusting in the direction of increasing the lift amount, the guide portion 17b, that is, the pin is rotated by rotating the adjustment screw 21 side in the direction in which the fixing screw 27 side is loosened from the state of FIG. The member 17 can be moved downward. As a result, the link member 15 is lowered, and the swing cam 7 can be rotated counterclockwise in FIG. 2 to adjust the lift amount in a larger direction.

In this case, as shown in FIG. 3, the adjusting screw 21 is loosened after loosening the locking nut 22 or 28 in a state where the guide portion 17b and the wedge-shaped member 25 are in close contact with each other through the inclined surfaces 17c and 25a. Alternatively, by further screwing the fixing screw 27, the guide portion 17b is elastically deformed, whereby the lift amount can be finely adjusted.

  Further, when the above-described lift amount is adjusted, a measurement point that can determine how much the link member 15 has moved relative to the rocker arm 13 is provided, so that the movement adjustment amount can be measured simultaneously with the adjustment. . After performing such a measurement, the adjustment work can be performed more efficiently by adjusting the lift amount.

  In addition, during the adjustment, the load applied during the actual valve lift operation is applied to the rocker arm 13 and the link member 15 while adjusting the lift amount while measuring the lift amount. Can prevent errors.

  In the other example of FIG. 4, the adjustment screw 29 is moved in the direction opposite to that of the adjustment screw 27 of FIG.

  In the above-described embodiment, the pin fixing portion 18 is provided on the rocker arm 13, but may be provided on the link member 15. In this case, a portion to be the guide portion 17 b of the pin member 17 is provided so as to be movable with respect to the link member 15, and a portion to be the pin portion 17 a of the pin member 17 is provided to be rotatable with respect to the rocker arm 12. At this time, the shape of the site | part which sets the pin fixing | fixed part 18 of the rocker arm 13 and the link member 15 differs from FIGS. 1-3.

  According to the above-described embodiment, when adjusting the valve lift amount, it is only necessary to operate the adjusting screw 21 and the fixing screw 27, and it is not necessary to disassemble the valve mechanism after assembling. It is extremely easy and can reduce production costs.

  According to the present invention, since the load applied during actual valve lift operation is applied to the rocker arm and the link member while adjusting the valve lift amount, it is possible to accurately adjust the lift amount. At the same time, errors due to backlash can be prevented.

Further, the rocker arm and the link member, and connected by the connecting shaft, the connecting shaft, so that the amount of valve lift is changed, to be movable in a radial direction of the coupling shaft relative the other of the rocker arm and the link member Since the fixing means for fixing the connecting shaft is provided at an appropriate position for this movement, the valve lift amount can be adjusted without disassembling after the assembly, and the valve lift amount can be easily adjusted.

To the other of the rocker arm and the link member, the movement guide portion connecting shaft moves provided, due to the provision of the adjusting means for movably adjusting the coupling shaft along the movement guide portion in the radial direction, of the connecting shaft The movement can be performed accurately and reliably.

  The fixing means is composed of a wedge-shaped member that is inserted from a direction intersecting the moving direction of the connecting shaft so as to press the connecting shaft in a direction opposite to the pressing direction by the adjusting means, so that the connecting shaft only needs to be pressed against the connecting shaft. Can be firmly fixed.

1 is a perspective view of a valve operating mechanism including a valve lift adjustment mechanism for an internal combustion engine according to an embodiment of the present invention. It is a side view of the valve mechanism of FIG. FIG. 2 is a detailed view of a pin fixing portion in the valve lift amount adjusting mechanism of FIG. 1. FIG. 6 is a detailed view showing another example of a pin fixing portion in the valve lift amount adjusting mechanism of FIG. 1.

Explanation of symbols

1 Intake valve
3 Drive shaft (camshaft)
7 Rocking cam 13 Rocker arm 15 Link member 17 Pin member (connection shaft)
19 Guide hole (movement guide)
21 Adjustment screw (Adjustment means)
25 Wedge-shaped member (fixing means)

Claims (3)

To oscillate the rocker arm in accordance with the rotation of the camshaft, this end of the rocker arm via the link member to swing the swing cam provided on the cam shaft by opening and closing the valve, the link member and the front Symbol rocker arm Are connected by a connecting shaft, and after measuring the valve lift amount, the valve lift amount adjusting method for the internal combustion engine is adjusted by changing the position of connecting the rocker arm and the link member of the connecting shaft. The connecting shaft includes a pin portion that rotatably supports one of the end portions of the rocker arm and the link member, and a guide portion integral with the pin portion, and the guide portion moves. A guide part is provided on the other of the rocker arm and the link member, and the guide part is moved together with the pin part in the radial direction of the pin part. After moving along the inside by an adjusting means to change the position of the connecting shaft, a wedge-shaped member is inserted from a direction intersecting the movement guide portion, and an inclined surface provided on the wedge-shaped member is formed on the guide portion. A method for adjusting a valve lift amount of an internal combustion engine, wherein the connecting shaft is fixed by sliding contact with an inclined surface provided so as to be pressed from a direction opposite to the pressing direction by the adjusting means .   2. The valve lift adjustment method for an internal combustion engine according to claim 1, wherein the load applied during actual valve lift operation is adjusted while measuring the valve lift while the load is applied to the rocker arm and the link member. In a valve lift adjustment mechanism for an internal combustion engine that swings a rocker arm as the camshaft rotates and swings a swing cam provided on the camshaft via a link member at the end of the rocker arm to open and close the valve. The rocker arm and the link member are connected by a connecting shaft. The connecting shaft includes a pin portion that rotatably supports one end portion of the rocker arm and the link member, and a guide integrated with the pin portion. The guide portion is provided with a movement guide portion that moves in the radial direction of the pin portion so that the valve lift amount changes , on either one of the rocker arm and the link member, and the guide portion adjusting means movably adjusted with the pin portion in a radial direction of said pin portion along the movement guide portion is provided, intersecting the movement guiding section Inserted from direction, said inclined surface provided on the guide portion by the movement appropriate position of the guide portion, provided with a wedge-shaped member which is brought into sliding contact pressing to fix the inclined surface pressing from the opposite direction direction by the adjusting means A valve lift adjustment mechanism for an internal combustion engine.

Images