JP4106012B2 - Valve operating device for internal combustion engine - Google Patents

Description

  The present invention relates to a valve operating apparatus for an internal combustion engine, and more particularly to a valve operating apparatus for an internal combustion engine provided with a plurality of swing cams for driving a plurality of intake valves per cylinder.

  As this type of conventional valve gear, there is one described in the following patent document filed earlier by the present applicant.

  Briefly, this valve operating device is applied to one having two intake valves per cylinder, and the shaft center is the axis of the drive shaft on the outer periphery of the drive shaft that rotates in synchronization with the rotation of the crankshaft. A drive cam eccentric from the center is fixed by a pin, and a cylindrical cam shaft is rotatably provided on the outer periphery of the drive shaft.

  The camshaft is integrally provided with a pair of left and right swing cams corresponding to a pair of intake valves on the outer periphery, and the rotational force of the drive cam is transmitted to the swing cam via a multi-joint link-shaped transmission mechanism. Then, each intake valve is opened and closed via a valve lifter.

  The transmission mechanism is disposed above each swing cam, and a rocker arm that is swingably supported on the control shaft via the control cam, and an annular portion at one end rotatably linked to the drive cam, and A link arm having a protruding other end rotatably connected to one end of the rocker arm, and one end rotatably connected to the other end of the rocker arm, the other end being the cam nose side of each rocking cam And a pair of link rods rotatably connected to each other.

And by controlling the rotational position of the control cam via the control shaft according to the engine operating state, by changing the rocking fulcrum of the rocker arm and controlling the rolling contact position of each rocking cam with respect to the valve lifter, The lift amount and operating angle of each intake valve are changed.
JP 2001-55915 A

  By the way, in the conventional valve operating device, a drive cam, a camshaft in which a pair of swing cams are integrally formed with respect to the drive shaft, and a journal portion supported by a bearing provided in the cylinder head. Such a large number of members are assembled or provided integrally in advance, but these members are arranged close to each other in the axial direction due to the limitation of the length of the valve mechanism in the axial direction.

  For this reason, in order to improve the ease of assembly to the drive shaft, the drive cam is formed by a separate member from the drive shaft, and positioning is performed at the time of assembling each member while utilizing the shaft radial direction pin or the like. It is designed to be assembled to the drive shaft.

  However, in such a configuration in which the drive cam is formed separately from the drive shaft and assembled later, the manufacturing cost and assembly cost are inevitably increased.

  Therefore, it is conceivable to reduce the costs by integrating the drive shaft and the drive cam at the time of molding. However, by simply integrating them, the members are arranged close to each other in the axial direction, and further, Since the projecting position and the projecting amount in the radial direction are different, it is impossible to assemble the link arm to the drive cam or assemble the cam shaft (swing cam) to the drive shaft.

  The present invention has been devised in view of the actual situation of the conventional valve gear, and the invention according to claim 1 is, in particular, provided with a drive cam integrally provided on a drive shaft and at least one swing cam. Are arranged adjacent to one side surface of the drive cam, and each swing cam is detachably divided with respect to the drive shaft, and another member integrally provided on the outer periphery of the drive shaft Among these, at least the outer diameter of the other member positioned in the axial direction from the drive cam to the one swing cam side is set smaller than the inner diameter of the fitting hole of the link arm, and on the drive shaft An axial separation distance between each of the other adjacent members including the drive cam is set to be larger than a width length of one end portion of the link arm.

  According to this invention, since the drive shaft and the drive cam are integrally formed, the cost can be reduced.

  Moreover, when assembling each member to the drive shaft, first, the link arm is inserted and inserted from one end side of the drive shaft through its own fitting hole, for example, through the journal portion, and then another member is attached. When passing, the next member is passed through the fitting hole by moving in the radial direction using the fact that the distance between each part is larger than the width of one end of the link arm. Thus, the link arm is assembled by finally fitting the fitting hole to the outer peripheral surface of the drive cam while sequentially repeating the movement in the axial direction and the movement in the radial direction.

  Thereafter, each swing cam that is divided in advance, for example, in a half-shape, is assembled to a predetermined outer peripheral position of the drive shaft from the outer radial direction by a bolt or the like. This makes it possible to easily and easily assemble the constituent members.

  Embodiments of a valve operating apparatus for an internal combustion engine according to the present invention will be described below in detail with reference to the drawings. The valve operating apparatus of this embodiment is provided with two intake valves per cylinder as in the prior art, and a two-cylinder internal combustion engine provided with a variable mechanism that makes the valve lift of each intake valve variable according to the engine operating state. Applied to institutions.

  1 to 3 show a valve operating apparatus according to the first embodiment. A pair of intake valves 2 and 2 slidably provided on a cylinder head 1 via a valve guide (not shown), and an engine An internal hollow drive shaft 3 disposed in the front-rear direction, two first and second drive cams 4 and 4 fixed to a predetermined position of the drive shaft 3 corresponding to each cylinder, and the drive shaft A pair of oscillating cams 5, 5 that are disposed at symmetrical positions about the respective drive cams 4 while being supported by 3, and that open the intake valves 2, 2 via valve lifters 6, 6. And a transmission mechanism 7 linked between each drive cam 4 and the swing cams 5 and 5 to transmit the rotational force of the drive cam 4 as the swing force (valve opening force) of the swing cams 5 and 5; And a control mechanism 8 for making the operating position of the transmission mechanism 7 variable.

  The intake valves 2 and 2 are closed in a closing direction by valve springs 9 and 9 elastically mounted between a bottom portion of a substantially cylindrical bore housed in an upper end portion of the cylinder head 1 and a spring retainer at the upper end portion of the valve stem. It is energized.

  As shown in FIGS. 4 and 5, the drive shaft 3 is disposed along the engine front-rear direction, and a circular attachment portion 32 for attaching a driven pulley (not shown) to the end portion on the engine front side is integrally provided. Rotational force is transmitted from the crankshaft of the engine via a timing belt wound around the driven pulley.

  Further, the drive shaft 3 is integrally provided with three columnar journal portions 33, 34, and 35 at the front end portion, the engine rear end portion and the substantially central position, respectively. The parts 33 to 35 are rotatably supported by three bearings 24 provided corresponding to the upper part of the cylinder head 1. Each of the journal portions 33 to 35 has an outer diameter D1 set smaller than an outer diameter D of the mounting portion 32.

  As shown in FIG. 1, the bearings 24 are arranged outside the valve lifters 6 and 6 for driving the intake valves 2 and 2 and are integrally formed at the upper end of the cylinder head 1 and are semicircular at the center. The base 24a has a bearing groove, and the bracket 24b has a semicircular bearing groove that is disposed at the top of the base 24a and supports the drive shaft 3 together with the bearing groove. Each bracket 24b is fixed to the base 24a by two bolts 25 and 26, respectively.

  As shown in FIGS. 4 and 5, the first and second drive cams 4, 4 are formed in a substantially disc shape with a predetermined thickness and sandwich the center journal portion 35 of the drive shaft 3. And the center Y is provided at a position eccentric from the axis X of the drive shaft 3, the outer peripheral surface 4a is formed in an eccentric cam profile, and the outer diameter D2 thereof is The outer diameter D of the mounting portion 32 is set smaller. The drive cams 4, 4 are arranged so as to protrude in opposite directions in the radial direction, and the centers Y, Y are in opposite positions across the axis X of the drive shaft 3.

  As shown in FIG. 2, each of the swing cams 5 has a substantially raindrop shape, and is supported so that the base end 5a side swings about the axis X of the drive shaft 3. A cam surface 5b is formed on each of the lower surfaces. The cam surface 5b includes a base circle surface on the base end portion 5a side, a ramp surface extending from the base circle surface to the cam nose portions 5c and 5c in an arc shape, and the lamp surface A lift surface that is continuous with the top surface of the maximum lift on the tip side of the cam nose portion 5c from the surface, and the base circle surface, the ramp surface, the lift surface, and the top surface are in a swing position of the swing cam 5. Accordingly, the upper surface of each valve lifter 6 is brought into contact with a predetermined position.

  Further, as shown in FIGS. 2 and 6 to 8, each of the swing cams 5, 5 is formed by dividing the base end portion 5 a vertically into a half shape with respect to the drive shaft 3. The parts 5d and 5e are coupled from above and below by the front and rear bolts 23 and 23, and in the coupled state, the respective semicircular inner surfaces are formed on a cylindrical sliding surface 5f that is in sliding contact with the outer peripheral surface of the drive shaft 3. Has been.

  Further, as shown in FIG. 1, the swing cams 5 and 5 are formed in a cylindrical extension at opposite end surfaces of the base end portions 5a and 5a, that is, hole edges on both sides of the slide surfaces 5f. The parts 27a, 27b, 28a, 28b are integrally formed.

  Each of the extended portions 27a, 27b, 28a, 28b has an overall length in the axial direction including each base end portion 5a so that the ring portion 11a of the link arm 11 has an annular length from the opposing surface of the bearings 24, 24. It is formed to the vicinity of both side surfaces in the axial direction, and the annular portion 11a is supported from both sides by the opposed inner end surfaces of the opposed inner extensions 27a, 28a. On the other hand, the outer end surfaces of the outer extensions 27b and 28b are in contact with the opposing surfaces of the bearings 24 and 24, respectively.

  Accordingly, the annular portion 11a is restricted from freely moving in the axial direction via both bearings 24, 24 by the respective extension portions 27a, 27b, 28a, 28b.

  The transmission mechanism 7 includes a rocker arm 10 disposed above the drive shaft 3, a link arm 11 that links the one end 10 a of the rocker arm 10 and the drive cam 4, and the other end 10 b of the rocker arm 10. A pair of link rods 12, 12 linking the cam 5 is provided.

  The rocker arm 10 has a support hole 10c penetratingly formed in a central cylindrical base from the lateral direction, and is supported by a control cam 17 described later via the support hole 10c so as to be swingable. Further, one end portion 10a extending from one side of the cylindrical base portion in the radial direction is formed with a notch portion 10d at the center to form a so-called two-surface width, while extending from the other side of the cylindrical base portion. The other end portions 10 b and 10 b which are the arm portions are formed in a bifurcated shape corresponding to the two swing cams 5.

  The bifurcated other end portions 10b and 10b are arranged at symmetrical positions around the cylindrical base portion, and pin holes 10d into which the pins 14 connected to the one end portion 12a of the link rod 12 are fitted at the respective front end portions. 10d is penetratingly formed. The other end portions 10b and 10b transmit the swinging force to the swing cams 5 from the upper side in the direction of gravity via the link rods 12 and 12, respectively. In addition, the rocker arm 10 has an entire lower surface 10e on the side of the drive cam 4 formed into a concave curved surface. Here, since the bifurcated other end portions 10b and 10b are arranged symmetrically with respect to the cylindrical base portion, the rocker arm 10 is not easily tilted and a stable lift operation is performed.

  The link arm 11 includes an annular portion 11a having a relatively large diameter on one end side, and a protruding end 11b on the other end side projecting at a predetermined position on the outer peripheral surface of the annular portion 11a. Is formed with a fitting hole 11c into which the outer peripheral surface 4a of the drive cam 4 is rotatably fitted, and the axial thickness W of the annular portion 11a is the same as that of the drive cam 4. It is set to be slightly larger than the wall thickness, and the drive cam 4 is held inside the fitting hole 11c. Accordingly, the link arm 11 is effectively regulated in the axial direction by the cylindrical extensions 27a and 27b. Further, the inner diameter D3 of the fitting hole 11c is set to be slightly larger than the outer diameter D2 of the driving cam 4, and holds the driving cam 4 so as to be freely slidable.

  On the other hand, the protruding end 11b is inserted into the notch 10d of the one end 10a of the rocker arm 10 and is rotatable to the one end 10a by a pin 13 inserted through a pin hole 11d formed penetrating in the inner axial direction. It is connected to.

  The link rod 12 is formed into a substantially U-shaped cross section by press molding, and the vicinity of both end portions 12a and 12b is a double plate, and pin holes 12c and 12d are formed therethrough. The pin holes 12c and 12d are rotatably connected to the pin 14 rotatably connected to the other end portions 10b and 10b of the rocker arm 10 and the cam nose portions 5c and 5c of the swing cams 5 and 5, respectively. A pin 15 is inserted.

  The control mechanism 8 includes a control shaft 16 that is rotatably supported by a bearing (not shown) disposed above the cylinder head 1, and a rocking fulcrum of the rocker arm 10 that is integrally fixed to the outer periphery of the control shaft 16. A control cam 17 is provided.

  The control shaft 16 is disposed in the longitudinal direction of the engine in parallel with the drive shaft 3 and within a predetermined rotation angle range via a gear mechanism by an electric actuator (DC motor) (not shown) provided at one end. The rotation is controlled. On the other hand, the control cam 17 has a cylindrical shape, and the position of the shaft center P1 is offset from the shaft center P2 of the control shaft 16 by a predetermined amount by the thick portion.

  The electric actuator is driven by a control signal from an engine controller (not shown) that detects the operating state of the engine. This controller has a built-in microcomputer, and a crank angle sensor, an air flow meter, a water temperature Based on detection signals from various sensors such as a potentiometer that detects the rotational position of the sensor and the control shaft 16, the current engine operating state is detected by calculation or the like, and a control signal is output to the electric actuator.

  The arrangement relationship of the drive cams 4, 4 and the journal portions 33 to 35 provided integrally with the drive shaft 3 is configured as shown in FIG. 4, and is integrated with the outer peripheral surface of the drive shaft 3. The separation distance L1 (the length of the shaft portion 3a of the drive shaft 3) between the inner end edge 34a of the rear side journal portion 34 provided on the rear side and the adjacent first drive cam 4 is the link arm 11's length. It is set larger than the width W of the annular portion 11a.

  Further, a separation distance L2 (shaft portion 3b) between the first drive cam 4 and the central journal portion 35, a separation distance L3 (shaft portion 3c) between the second drive cam 4 and the central journal portion 35, a first 2 The distance L4 (shaft portion 3d) between the drive cam 4 and the journal portion 33 on the front end side is also set larger than the width length W of the annular portion 11a.

  Furthermore, between the outer peripheral surface 4a of the drive cam 4 and the inner peripheral surface of the fitting hole 11c of the link arm 11, between the outer peripheral surface of the control cam 17 and the inner peripheral surface of the support hole 10c of the rocker arm 10, and Is provided with a lubricating oil supply circuit for lubricating the journal portions 33 to 35 and the bearing 24.

  That is, as shown in FIGS. 1 and 2, the lubricating oil supply circuit is formed along the inner axial direction of the drive shaft 3, and the first oil passage 18 whose rear side is closed, and the drive shaft 3. The first oil passage 18, the outer peripheral surface 4 a of the drive cam 4, and the fitting hole 11 c of the link arm 11 are communicated with each other. A first communication passage 19 to be formed, a second oil passage 20 formed along the inner axial direction of the control shaft 16, and a diameter formed in the diameter direction of the control shaft 16 to communicate with the second oil passage 20. A directional hole 21 is formed in the thick portion of the control cam 17 along the radial direction, and communicates between the diametric hole 21, the inner surface of the support hole 10 c of the rocker arm 10, and the outer surface of the control cam 17. A communication path 22 is provided.

  The first oil passage 18 includes an oil introduction passage 30 formed continuously from the oil gallery inside the cylinder head 1 to the inside of the bearing 24, and an oil hole 31 formed radially in the peripheral wall of the drive shaft 3. Thus, lubricating oil is introduced into the interior. Further, the groove groove 31 a on the inner peripheral surface of the bearing 24 that communicates with the oil hole 31, and the groove groove 36 a on the inner peripheral surface of the bearing 24 that communicates with the oil hole 36 formed in the inner radial direction of the rear side journal portion 34. Between each journal part 33-35 and the bearing 24, it lubricates.

  Also, the lubricating oil is introduced into the second oil passage 20 from the oil gallery through an oil introduction passage formed in a bearing (not shown) and a radial oil hole of the control shaft 16. Yes.

  Hereinafter, the operation of the variable mechanism in the present embodiment will be briefly described. During the low lift control, the control shaft 16 is rotationally driven in one direction via the electric actuator by a control signal from the controller. For this reason, as shown in FIGS. 9A and 9B, the thick portion of the control cam 17 rotates to the right in the drawing with respect to the control shaft 16 and is held at the rotation angle position. Thereby, the other end part 10b side of the rocker arm 10 is rotated upward. For this reason, each swing cam 5 is forcibly pulled up on the cam nose portion 5 c side via the link rod 12, and the entire swing cam 5 shifts to the clockwise rotation position of FIG. 9.

  Therefore, when the drive cam 4 rotates and the link arm 11 pushes up the one end portion 10a of the rocker arm 10, the lift amount is transmitted to the swing cam 5 and the valve lifter 6 via the link rod 12, as shown in FIG. 9B. However, the lift amount is sufficiently small.

  Therefore, the valve lift amount (L1) of the intake valves 2 and 2 is reduced, the opening timing is delayed, and the valve overlap with the exhaust valve is reduced. For this reason, for example, an improvement in fuel consumption in a low load region and a stable rotation of the engine can be obtained.

  On the other hand, at the time of high lift control, the control shaft 16 is driven to rotate in the other direction by the electric actuator by a control signal from the controller. Therefore, as shown in FIGS. 10A and 10B, the control shaft 16 rotates the control cam 17 to a predetermined rotational angle position and moves the thick portion downward. For this reason, the other end portion 10b side of the rocker arm 10 moves downward to press the cam nose portion 5c of the swing cam 5 downward via the link rod 12 so that the entire swing cam 5 is clockwise in FIG. Move to the pivot position.

  Therefore, the contact position of each cam surface 5b with respect to the upper surface of each valve lifter 6 of each swing cam 5 moves toward the cam nose portion 5c. Therefore, when the drive cam 4 rotates and pushes up the one end portion 10a of the rocker arm 10 via the link arm 11, the lift amount with respect to the valve lifter 6 increases as shown in FIG. 10B.

  Therefore, the valve lift amount L2 of each intake valve 2 is increased so that the opening timing is advanced and the closing timing is delayed. As a result, for example, the intake charging efficiency in a high load region is improved, and a sufficient output can be secured.

  And according to this embodiment, since each drive cam 4 and 4 was integrally formed with respect to the drive shaft 3, while being able to achieve cost reduction, the backlash between the drive cam 5 and the drive shaft 3 is here. Since there is no occurrence, there is no unexpected tilting of the drive cam 5, and the occurrence of lift variations among cylinders can be sufficiently suppressed. In addition, the drive cam surface can be sufficiently lubricated without the problem of oil leakage from the play and the gap, and the lift is stable and stable from this point.

  When each member is assembled to the drive shaft 3, before assembling the drive shaft 3 to the bearings 24, 24 of the cylinder head 1 and before assembling the swing cams 5, 5 to the drive shaft 3, first each link arm is assembled. 11 and 11 are assembled. That is, first, one link arm 11 on the front side is fitted and inserted from the rear end side of the drive shaft 3 through the fitting hole 11c of the annular portion 11a, and then passed through the rear side journal portion 34. By using the fact that the distance L1 between the journal portion 34 and the first drive cam 4 is larger than the width length W of the ring portion 11a of the link arm 11, the end portion of the fitting hole 11c is set in the radial direction. Is moved by a predetermined amount (d1 shown in FIG. 4), and the first drive cam 4 is passed through the fitting hole 11c.

  Thereafter, the center journal portion 35 is passed through the fitting hole 11c of the link arm 11 while moving again in the radial direction using the separation distance L2, and further moved in the radial direction using the separation distance L3. The fitting hole 11 c is fitted to the outer peripheral surface 4 a of the second drive cam 4.

  Next, the annular portion 11 a of the rear side link arm 11 is moved in the radial direction after passing the rear side journal portion 34 by the same operation as described above, and the fitting hole 11 c of the first drive cam 4 is moved. It is made to fit in the outer peripheral surface 4a.

  Thus, the annular portions 11a and 11a of the link arms 4 and 4 on the front side and the rear side can be easily and easily fitted and held on the first and second drive cams 4 and 4, respectively.

  Thereafter, the swing cams 5 and 5 that are divided in advance in half are assembled with the bolts 23 and 23 so as to be aligned with the shaft portions 3a to 3d on both sides of the drive cams 4 and 4 from the outer radial direction. At the same time, the cam nose portions 5 b and 5 b are assembled to the link rods 12 and 12 while being positioned by the pins 15 and 15. The pins 15 and 15 are prevented from coming off by a snap ring or the like not shown.

  Next, the drive shaft 3 is assembled on the cylinder head 1 with the bolts 25 and 26 with the journal portions 33 to 35 disposed on the bearings 24 and 24.

  As described above, the integration of the drive shaft 3 and the drive cams 4 and 4 and the division of the swing cams 5 and 5 make it possible to easily and easily assemble the components, The assembly cost can be reduced.

  Although the swing cams 5 and 5 are formed separately, the assembly work need not be performed from the axial direction of the drive shaft 3 as in the prior art, and the overall assembly work efficiency is greatly improved. . Therefore, the assembly work cost can be reduced.

  Furthermore, in this embodiment, since the journal portions 33 to 35 are provided integrally with the drive shaft 3, it is not necessary to provide them on the swing cams 5 and 5 side, so that the structure is simplified.

  Further, since the swing cams 5 and 5 are independent from each other, the axial length of the swing cams 5 and 5 can be shortened. For this reason, even if it is a divided structure, sufficient torsional rigidity can be ensured. Further, fine adjustment of the lift amount of the swing cams 5 and 5 for each intake valve 2 and 2 can be performed independently, for example, by selecting the length of the link rod.

  Further, according to this embodiment, the link arm 11 has the protruding end 11b held in the notch 10d of the one end 10a of the rocker arm 10 to restrict the movement in the left-right direction and the annular portion 11a. Is held in contact with and supported by the extended portions 27a, 27b, 28a, 28b of the swing cams 5, 5, that is, in a state in which the operation of the link arm 11 and the swing cams 5, 5 is not hindered. Thus, free movement in the axial direction on the annular portion 11a side is restricted. For this reason, tilting of the link arm 11 is prevented, and partial contact between the inner peripheral surface of the fitting hole 11c of the annular portion 11a and the outer peripheral surface 4a of the drive cam 4 is prevented.

  As a result, wear of the inner peripheral surface of the fitting hole 11c and the outer peripheral surface 4a of the drive cam is prevented, and durability can be improved.

  On the contrary, since the swing cams 5 and 5 are positioned in the axial direction, the swing cams 5 and 5 are not inadvertently moved in the axial direction on the drive shaft 3. Therefore, a stable and reliable opening / closing operation of the intake valves 2 and 2 by the swing cams 5 and 5 is obtained.

  Next, the operation of the lubricating oil supply circuit in this embodiment will be described. During the operation of the engine, the lubricating oil supplied into the first oil passage 18 via the groove groove 31a passes from the groove groove 36a to the outer peripheral surface of the journal portion 35 (same for 33) and the inner peripheral surface of each bearing 24. Force lubrication between. Further, as shown in FIGS. 1 and 2, the lubricating oil in the first oil passage 18 flows into the first communication passage 19 and is formed between the inner peripheral surface of the fitting hole 11 c and the outer peripheral surface 4 a of the drive cam 4. Is supplied into the first sliding gap C. Therefore, the space between the outer peripheral surface 4a of the drive cam 4 and the fitting hole 11c of the link arm 11 is forcibly lubricated to improve the lubrication performance.

  Therefore, in combination with the free movement restricting action of the annular portion 11a in the left-right direction (the axial direction of the drive shaft 3), the occurrence of wear between the annular portion 11a and the drive cam 4 is effectively prevented. Can do. Further, the action of the lubricating oil film prevents the link arm 11 from falling, and the lift variation is reduced by stabilizing the posture.

  Moreover, the lubricating oil that flows out between the inner peripheral surface of the fitting hole 11c and the outer peripheral surface 4a of the drive cam 4 is the outer surface of the annular portion 11a and the extended portions 27a to 28b of the swing cams 5 and 5. Therefore, the lubrication performance of the part is also improved. Further, the lubricating oil supplied to the opposite end portion falls on the upper surface of the valve lifter 6, and the lubricating performance between the swing cams 5, 5 and the upper surface of the valve lifter 6 is improved.

  On the other hand, the lubricating oil supplied into the second oil passage 20 passes through the diameter direction hole 21 and the second communication passage 22, and the second sliding gap C <b> 2 between the inner surface of the support hole 10 c and the outer surface of the control cam 17. Supplied in. Therefore, the space between the control cam 17 and the rocker arm 10 is forcibly lubricated.

  11A and 11B show the second embodiment. Based on the structure of the drive shaft 3 in the first embodiment, a trigger portion 37 for detecting the rotational speed and the rotation angle is provided at the rear side end portion of the drive shaft 3. It is provided integrally.

  The trigger portion 37 includes a shaft portion 37a that extends coaxially with the drive shaft 3 from the journal portion 34 in the axial direction, and a protruding portion 37b that protrudes radially on the outer peripheral surface of the tip portion of the shaft portion 37a. A radial length D4 from the outer periphery of the shaft portion 37a to the tip of the protruding portion 37a is set to be smaller than the inner diameter D3 of the fitting hole 11c, and the inner end edge of the protruding portion 37a and the rear side journal The axial length L5 to the opposite end edge of the portion 34 is set to be larger than the width length W of the annular portion 11a.

  Therefore, to assemble the link arm 11 to the drive cam 4, the annular portion 11a is passed through the trigger portion 37 through the fitting hole 11c, and after the passage, the annular portion 11a is moved in the radial direction by a predetermined amount (de). By moving it slightly, it becomes possible to pass the rear side journal part 34 after that. The subsequent operation is the same as described above.

  Therefore, according to this embodiment, even if the trigger part 37 exists, assembly workability | operativity etc. improve like 1st Embodiment.

The technical ideas other than the invention described in the claims, as grasped from the embodiment, will be described below.
(1) The valve operating apparatus for an internal combustion engine according to claim 1, wherein the one of the other members is a journal portion provided integrally with the drive shaft.

According to the present invention, since the journal portion is directly provided on the drive shaft, it is not necessary to provide the journal portion on the swing cam side, so that the entire structure can be simplified.
(2) The valve operating apparatus for an internal combustion engine according to (1) or (2), wherein the swing cam is disposed between the drive cam and the journal portion and is positioned in the axial direction.

According to the present invention, the positioning of the rocking cam in the axial direction prevents the rocking cam from inadvertently moving in the axial direction on the drive shaft. Therefore, a stable and reliable opening / closing operation of the engine valve by the swing cam is obtained, and the valve lift is stabilized.
(3) The valve operating device for an internal combustion engine according to any one of claims 1 to 2, wherein each of the swing cams is provided independently corresponding to each engine valve.

  According to this invention, since it is independent, it becomes possible to shorten the length of each rocking cam in the axial direction. For this reason, even if it is a divided structure, sufficient torsional rigidity can be ensured.

In addition, fine adjustments such as the lift amount of the swing cam for each engine valve can be performed independently.
(4) The lubricating oil is supplied from the inside of the drive shaft between the outer peripheral surface of the drive cam and the inner peripheral surface of the fitting hole of the link arm. A valve operating apparatus for an internal combustion engine according to claim 1.

According to this invention, the lubricity between the outer peripheral surface of the drive cam and the inner peripheral surface of the fitting hole of the link arm is improved, and smooth rotation and smooth valve lift operation can be obtained at all times. The lubricating oil that has flowed out of the oil is also supplied to the adjacent swing cam.
(5) The rocker arm is swingably supported on the rocker shaft via a control cam, and the rocking fulcrum of the rocker arm is changed according to the rotational position of the control cam, thereby making the lift amount of the engine valve variable. The valve operating apparatus for an internal combustion engine according to any one of claims 1 to 4, characterized in that:

  Although the lift amount of the engine valve can be varied depending on the rotational position of the control cam, the absolute value of the intake air amount in the cylinder is small at the time of the minimum lift control, and there is a possibility that the influence of the variation among the cylinders may increase due to the backlash of each part. However, in the present invention, since the drive cam is integrated with the drive shaft as described above, there is no backlash or gap between them, so that the drive cam is not attached or tilted. It is possible to sufficiently suppress the occurrence of variations in lift between the two. In addition, since there is no risk of oil spilling from backlash or gaps, the lubrication performance on the outer periphery of the drive cam is improved, and at the same time, a smoother lift operation can be realized.

  The present invention is not limited to the configuration of each of the embodiments described above, and can be applied not only to the intake valve side but also to the exhaust valve side. It is also possible to apply to a valve operating device. The valve lifter is not limited to a type that moves up and down, but can also be a type that rocks about one fulcrum and presses the engine valve at one end (rocker arm).

  Furthermore, the present invention can be applied not only to a 2-cylinder internal combustion engine but also to a multi-cylinder internal combustion engine having three or more cylinders.

  Moreover, although the case where the link arm 11 was inserted from the rear side of the drive shaft 3 was shown in the said embodiment, when the outer diameter D of the attaching part 32 is smaller than the inner diameter D3 of the fitting hole 11c, the link arm 11 is shown. Can be inserted from the attachment portion 32 side, and can be inserted from both the front side and the rear side.

It is sectional drawing which expands and shows the valve gear which concerns on the 1st Embodiment of this invention. It is a side view of the valve gear of this embodiment. It is a top view of the valve gear of this embodiment. It is a front view of the drive shaft provided for this embodiment. It is A arrow directional view of FIG. It is a perspective view of the valve gear of this embodiment. It is a perspective view which shows the valve gear of this embodiment. It is a front view of the valve gear of this embodiment. A is an operation explanatory view showing the closed operation state of the intake valve during the minimum lift control by the valve operating apparatus of the present embodiment, and B is an operation description showing the open operation state of the intake valve during the minimum lift control. A is an operation explanatory view showing the closed operation state of the intake valve during the maximum lift control by the valve operating apparatus of the present embodiment, and B is an operation description showing the open operation state of the intake valve during the maximum lift control. A is a front view of the drive shaft used for the 2nd Embodiment of this invention, B is a B arrow directional view.

Explanation of symbols

1 ... Cylinder head 2 ... Intake valve (engine valve)
DESCRIPTION OF SYMBOLS 3 ... Drive shaft 3a-3d ... Shaft part 4 ... Drive cam 5 ... Swing cam 7 ... Transmission mechanism 8 ... Variable mechanism 10 ... Rocker arm 11 ... Link arm 11a ... Ring part 11c ... Fitting hole 33-35 ... Journal part (Other parts)

Claims (1)

A drive cam having a substantially circular shape, in which the rotational force of the drive shaft is transmitted, and the shaft center is provided eccentric to the shaft center of the drive shaft;
A link arm that holds the drive cam in a freely slidable manner in a fitting hole at one end and converts the rotational force from the drive cam into a reciprocating motion;
A rocker arm that swings by a driving force transmitted from the link arm;
A valve operating apparatus for an internal combustion engine, comprising: a plurality of swing cams supported by the drive shaft so as to be swingable and swinging by a swinging force transmitted from the rocker arm to drive a plurality of engine valves;
While providing the drive cam integrally with the drive shaft,
The at least one swing cam is disposed close to one side of the drive cam, and each swing cam is detachably formed with respect to the drive shaft,
Of the other members integrally provided on the outer periphery of the drive shaft, at least the outer diameter of the other member positioned in the axial direction from the drive cam to the one swing cam side is set to the fitting hole of the link arm. And set smaller than the inner diameter of
The internal combustion engine is characterized in that an axial separation distance between each of the other adjacent members including the drive cam on the drive shaft is set larger than a width length of one end portion of the link arm. Valve device.

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