JP2011122546A - Variable valve system of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a variable valve system capable of holding engine valve stably at a larger working angle and/or lift amount than the minimum working angle and/or lift amount when the engine is at a standstill. <P>SOLUTION: A holding mechanism 35 is equipped with a plurality of arm members 36 provided at several places on a control shaft 24 in such a manner as protruding in the radial direction, a plurality of plungers 39 installed able to abut to the flank in the swinging direction of each arm member in which the control shaft enlarges the lift amount and the working angle of a suction valve 3, and coil springs 40 to which the plungers give the energizing forces to respective arm members. When the control shaft rotates to a minute lift control position when the engine is stopped, the plungers press the respective arm members and rotate the control shaft to a minor lift control position to suit the starting. Thus good starting characteristics of the engine are secured. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a variable valve operating apparatus for an internal combustion engine that can vary at least the operating angle (opening period) of an intake valve and an exhaust valve, which are engine valves, according to an engine operating state.

  As is well known, a variable valve device that makes the operating angle of the intake valve and the valve lift variable by controlling the rotation of the control shaft is positive or negative caused by the urging force of the valve spring when the engine is stopped. Due to this alternating torque, the control shaft is automatically rotated in a direction in which the operating angle of the intake valve and the valve lift amount are reduced.

  For this reason, in a variable valve system in which the minimum operating angle and the minimum lift amount are not suitable for engine starting, for example, zero or a minute operating angle / lift close to zero, it may be difficult to start the engine.

  Therefore, in the variable valve operating apparatus disclosed in Patent Document 1 below, the plunger urged by the spring is applied to the cam provided on the control shaft so that the operation is greater than the minimum operating angle or the minimum lift when the engine is stopped. A technique for improving the startability of the engine by maintaining the angle and the lift amount is also provided.

JP 2003-269123 A

  However, in the prior art described in Patent Document 1, since the plunger and the cam are biased and held at only one position in the axial direction of the control shaft, the biasing holding force with respect to the control shaft is sufficiently large. Can not do it.

  As a result, there is a technical problem that the desired operating angle and lift amount suitable for starting cannot be stably maintained.

  The present invention has been devised in view of the technical problem of the conventional variable valve operating device, and the invention according to claim 1 is, in particular, the control shaft in the rotational direction in which the operating angle of the engine valve becomes large. A plurality of biasing means for biasing are provided at a plurality of locations in the axial direction of the control shaft.

  According to the first aspect of the present invention, when the engine is stopped, the control shaft is urged by the plurality of urging means, so that the operation angle and the lift amount larger than the minimum operation angle and the minimum lift amount are stably maintained. It becomes possible to do.

It is a schematic longitudinal cross-sectional view of the internal combustion engine to which this embodiment is applied. It is a perspective view of the variable valve apparatus in 1st Embodiment. It is an overhead view of the variable valve apparatus in this embodiment. It is principal part sectional drawing of the variable valve apparatus of this embodiment. It is operation | movement explanatory drawing of this embodiment. It is operation | movement explanatory drawing of this embodiment. It is a principal part perspective view of the variable valve apparatus of 2nd Embodiment. It is a disassembled perspective view of the control axis | shaft provided to this embodiment, a bracket, and an arm member. A and B are operation explanatory views at the time of minimum lift control of the present embodiment. A and B are operation explanatory views at the time of maximum lift control of the present embodiment. It is a graph which compares and shows the actual lift characteristic when not having a lift adjustment mechanism, and a theoretical lift characteristic. It is a graph which compares and shows the actual lift characteristic in the case of having a lift adjustment mechanism, and a theoretical lift characteristic. It is a graph which compares and shows the actual lift characteristic at the time of having a lift adjustment mechanism and a 2nd lift adjustment mechanism, and a theoretical lift characteristic. A and B are operation explanatory views at the time of minimum lift control of the variable valve operating apparatus in the third embodiment. A and B are operation explanatory views at the time of maximum lift control of the variable valve operating apparatus in the third embodiment. It is the schematic which shows a partial cross section of the variable valve apparatus of 4th Embodiment.

Hereinafter, embodiments of a variable valve operating apparatus for an internal combustion engine according to the present invention will be described in detail with reference to the drawings. In this embodiment, the variable valve operating device is applied to the intake side of one-bank three-cylinder of a V-type six-cylinder internal combustion engine.
[First Embodiment]
The internal combustion engine 01 has a general structure as shown in FIG. 1 and includes a cylinder block 04 in which a crankshaft 02 is rotatably accommodated and a piston 03 is slidably accommodated in a cylinder bore. A cylinder head 05 which is arranged and fixed at the upper end of the cylinder block 04 and closed at the upper end by a head cover 06, and an intake side valve operating device 07 and an exhaust side provided at the upper end of the cylinder head 05 for each cylinder. And a variable mechanism for varying the valve lift amount and the operating angle of the intake valves 3 and 3 according to the engine operating state. .

  As shown in FIGS. 1 to 4, the intake side valve operating device 07 having the variable mechanism is slidably provided on the cylinder head 05 via a valve guide (not shown) to open and close the intake port 1. Two intake valves 3, 3 per cylinder, an internal hollow drive shaft 4 arranged in the longitudinal direction of the engine, and each swing arm 6 as a follower disposed at the upper end of each intake valve 3, 3. 6, a pair of swing cams 7, 7 for opening and closing each intake valve 3, 3 and a drive cam 5, which will be described later, and the swing cams 7, 7 of the drive shaft 4 are linked together to drive the drive. A transmission mechanism 8 that converts the rotational force of the cam 5 into a swinging motion and transmits the swinging force to the swinging cams 7 and 7, and a valve lift amount of each of the intake valves 3 and 3 by changing the posture of the transmission mechanism 8 And a control mechanism 9 that variably controls the operating angle according to the engine operating state. The operating angle refers to a period during which the intake valves 3 and 3 are open.

  The intake valves 3, 3 are connected to the intake port 1 by a valve spring 10 that is elastically mounted between a bottom portion of a substantially cylindrical bore housed in an upper end portion of the cylinder head 05 and a spring retainer 3 a at the upper end portion of the valve stem. It is urged in the direction of closing each open end.

  The drive shaft 4 is provided with the drive cam 5 on the outer periphery, and is rotatably supported by five bearing portions 11 provided on the upper portion of the cylinder head 05. Further, the drive shaft 4 is rotated in the clockwise direction (arrow direction) in FIG. 1 by receiving a rotational force from the crankshaft of the engine via a sprocket (not shown) provided at one end.

  The drive cam 5 includes a cam main body formed in a substantially disc shape and a cylindrical boss portion provided integrally with an outer portion of the cam main body, and is pierced in a radial direction in the boss portion. It is fixed to the drive shaft 4 via a fixing pin inserted through the pin hole. The drive cam 5 is disposed on one end side of the swing cams 7 and 7, and the boss portion is disposed at a position opposite to the swing cams 7 and 7 with the cam body interposed therebetween. . Therefore, the cam body side is located on the swing cams 7 and 7 side through the spacer. The cam body is formed in an eccentric circular cam profile, and the axis Y is offset from the axis X of the drive shaft 4 in the radial direction by a predetermined amount.

  As shown in FIGS. 1 and 4, each swing arm 6 has a lower surface of the concave one end 6a abutting against a stem end of each intake valve 3, and a spherical lower surface of the other end 6b is a cylinder head. The hydraulic rascia adjuster 13 is held in contact with and supported by the spherical head of the hydraulic rascia adjuster 13 held in the holding hole 1a formed at 05, and swings about the head of the hydraulic rascia adjuster 13 as a pivot point. . Further, the swing arm 6 is rotatably supported by a roller 14 with which each swing cam 7 abuts at a substantially hollow center position.

  As shown in FIGS. 1 and 4, each of the swing cams 7 has a substantially raindrop shape with the same shape, and a cylindrical camshaft 7 a that is fitted on the outer peripheral surface of the drive shaft 4 is provided on the base end side. It is integrally formed and is supported by the cam shaft 7a so as to be swingable about the axis X of the drive shaft 4 as a swing support shaft. Each swing cam 7 has a cam surface 7c formed on the lower surface between the base end portion and the cam nose portion 7b on the distal end side. The cam surface 7c includes a base circle surface on the base end side, a ramp surface extending in an arc shape from the base circle surface to the cam nose portion 7b, and a peak of the maximum lift from the ramp surface to the distal end side of the cam nose portion 7b. The base circle surface, the ramp surface, the lift surface, and the top surface are formed on the outer peripheral surface of the roller 14 of each swing arm 6 according to the swing position of the swing cam 7. It comes into contact with the displaced position.

  Each swing cam 7 has the same swing direction as the rotation direction (arrow direction) of the drive shaft 4 in which the cam surface 7c moves toward the lift surface and opens the intake valves 3 and 3. Has been. Therefore, a rotating torque is generated in the direction in which each rocking cam 7 is lifted by the coefficient of friction between the drive shaft 4 and each rocking cam 7. For this reason, the drive efficiency of each rocking cam 7 improves.

  Further, the swing cam 7 on the drive cam 5 side is integrally provided with a connecting portion 7d at a position opposite to the cam nose portion 7b with the cam shaft 7a interposed therebetween. A pin hole through which the connecting pin 20 connected to the other end of the link rod 17 is inserted is formed in both side surfaces.

  The rollers 14 are arranged so as to protrude from the upper surfaces of the swing arms 6, and a relatively large gap is formed between the upper surfaces of the swing arms 6 and 6. Interference between the swing arms 6 and 6 and the connecting portions 7d of the swing cams 7 and 7 and the other end portion 17b of the link rod 17 is prevented. Therefore, the interference can be prevented even at the position where each swing cam 7 is the most jumped up.

  As shown in FIGS. 1 to 4, the transmission mechanism 8 includes a rocker arm 15 disposed above the drive shaft 4 along the engine width direction, and a link arm 16 that links the rocker arm 15 and the drive cam 5. The rocker arm 15 and the link rod 17 that links the connecting portion 7d of the one swing cam 7 form a multi-node link mechanism.

  The rocker arm 15 is provided with a cylindrical base portion 15a on one end side that is swingably supported by a control eccentric shaft 26, which will be described later, and a bifurcated projection from the outer surface of the cylindrical base portion 15a to the inside of the engine. It consists of first and second arm portions 15b and 15c.

  The cylindrical base portion 15a is formed with a support hole 15d penetratingly formed on the outer periphery of a control eccentric shaft 26 to be described later with a small clearance.

  The first arm portion 15 b has a bifurcated tip, and a projecting end of the link arm 16 to be described later is rotatably connected between the bifurcated portions via a connecting pin 12.

  On the other hand, the second arm portion 15c is provided with a lift adjusting mechanism 21 at a block portion 15f at the tip, and a later-described one end portion of the link rod 17 on a pivot pin 19 described later of the lift adjusting mechanism 21. 17a is rotatably linked. Further, on both sides of the block portion 15f, a long hole (not shown) through which the pivot pin 19 can move in the vertical direction is formed penetrating from the lateral direction.

  In addition, the first arm portion 15b and the second arm portion 15c are provided at different angles in the swinging direction and are disposed in a vertically misaligned state, and the distal end portion of the first arm portion 15b is the second arm portion. It inclines below with a slight inclination angle from the front-end | tip part of 15c.

  The link arm 16 includes an annular portion having a relatively large diameter and the protruding end projecting at a predetermined position on the outer peripheral surface of the annular portion, and the drive cam 5 is provided at a central position of the annular portion. A fitting hole 16a for rotatably fitting and supporting the outer peripheral surface of the fitting is formed.

  Each of the link rods 17 is integrally formed by press molding and has a substantially U-shaped cross section, and the inside is bent into a substantially arc shape for compactness, and has one end portion. 17a is connected to the distal end portion of the second arm portion 15c via the pivot pin 19 inserted into the pin hole, and the one swing cam is connected to the other end portion 17b via the connecting pin 20 inserted into the pin hole. 7 is connected to a connecting portion 7d in a rotatable manner. Further, since only one link rod 17 is provided per cylinder, the structure can be simplified and the weight can be reduced.

  Also, the link cam 17 causes the swing cam 7 to lift the intake valves 3 and 3 by lifting the connecting portion 7d, but the cam nose portion 7b receiving the input from the roller 14 is connected to the swing center. Since it is arranged on the opposite side of the portion 7d, the occurrence of the tilting of each swing cam 7 can be suppressed.

  The lift adjusting mechanism 21 is formed in the lower support hole 19 of the block portion 15f of the second arm portion 15c of the rocker arm 15 and in the lower portion of the block portion 15f toward the longer hole. An adjustment bolt (not shown) screwed into the adjusted female screw hole from below, and a lock screwed from above into a fixing female screw hole (not shown) formed in the upper portion of the block portion 15f toward the long hole. Bolts 22 are provided.

  Then, after assembling each component, the lift amount of each intake valve 3 and 3 is finely adjusted by adjusting the vertical position of the pivot pin 19 in the elongated hole with the adjustment bolt, and the adjustment work is completed. At this point, the position of the pivot pin 19 is fixed by tightening the locking bolt 22.

  As shown in FIGS. 1, 2, and 4, the control mechanism 9 includes an internal hollow control shaft 24 that is disposed in parallel with the upper position of the drive shaft 4, and projects radially from the control shaft 24. A bracket 25 as a support member provided, a hollow control eccentric shaft 26 provided at the tip of the bracket 25, and an actuator 31 that rotationally drives the control shaft 24 are provided.

  The control shaft 24 has a flat surface 24a having a predetermined length at a position corresponding to each cylinder on the outer peripheral surface, and a pair of female screw holes 24b in the inner radial direction at substantially both end sides of the flat surface 24a. It is formed through.

  The bracket 25 is formed in a substantially U shape, and as shown in FIGS. 4 and 5, as shown in FIGS. 4 and 5, an elongated plate-like support piece 27 arranged along the axial direction on the flat surface 24 a side of the control shaft 24. And bracket pieces 28, 28 which are support portions provided integrally at both ends in the longitudinal direction of the support piece 27.

  The length of the support piece 27 is set to be substantially the same as the length of the cylindrical base portion 15 a of the rocker arm 15, and the width length is set to be slightly larger than the outer diameter of the control shaft 24. ing. The support piece 27 is formed with a pair of bolt insertion holes 27 a at positions corresponding to the female screw holes 24 b of the control shaft 24.

  The bracket pieces 28, 28 protrude from both end portions of the support piece 27 in an approximately L shape at an angle of about 90 ° with respect to the upper surface, and at both end portions, both end portions of the control eccentric shaft 26. Support holes 28a and 28a for fixing and supporting are provided, and shaft insertion holes 28b and 28b through which the control shaft 24 is inserted are provided on the base end side.

  The bracket 25, together with an arm member 36, which will be described later, by a pair of fixing bolts 30 and 30 inserted and screwed into both bolt insertion holes 27a and 27a of the support piece 27 and both female screw holes 24b and 24b of the control shaft 24, respectively. The control shaft 24 is fastened together.

  As described above, the control eccentric shaft 26 rotatably supports the cylindrical base portion 15a of the rocker arm 25, and both ends thereof are fixed to the support holes 28a and 28a of the bracket pieces 28 and 28 by, for example, caulking. ing. Further, the control eccentric shaft 26 is eccentric with a relatively large eccentric amount α with respect to the axis P1 of the control shaft 24.

  The actuator 31 includes an electric motor 32 fixed to the rear end portion of the cylinder head 05 and a ball screw mechanism 33 that is a speed reducer that transmits the rotational driving force of the electric motor 32 to the control shaft 24. Yes.

  The electric motor 32 is constituted by a proportional type DC motor, and is driven by a control signal from an electronic controller 34 for detecting the operating state of the engine. The electronic controller 34 is a variety of devices such as a crank angle sensor that detects the engine speed, an air flow meter that detects the intake air amount, a water temperature sensor that detects the engine water temperature, and a potentiometer that detects the rotational position of the control shaft 24. A detection signal from the sensor is fed back to detect the current engine operating state by calculation or the like, and a control signal is output to the electric motor 32. According to the actuator that is rotationally driven by such an electric motor 32, quick switching response can be expected regardless of the oil temperature of the engine.

  The actuator 31 controls forward and reverse rotation of the control shaft 24, and the valve lift amount (operating angle) of the intake valves 3 and 3 from the minute lift to the maximum lift via the transmission mechanism 8 and the like according to the rotational position. It comes to control.

  Further, the control shaft 24 is held by a holding mechanism 35 provided for each cylinder at a rotation position where the rotation position is controlled to be a small lift that is larger than the minute lift and is suitable for starting the engine when the internal combustion engine 01 is stopped. It has come to be.

  That is, as shown in FIGS. 2 to 6, the holding mechanism 35 is provided in each cylinder, and an arm member 36 whose base end portion 36 a is fixed to the control shaft 24 side, and the arm member 36. The urging means 37 is configured to press the front end portion 36b from below and rotate the control shaft 24 by a predetermined amount in the clockwise direction (the direction in which the valve lift amount is increased) in FIG.

  Each of the arm members 36 is formed in a flat plate shape, and a pair of bolt holes 36c are formed at a position in the width direction on the base end portion 36a side, and the base end portion 36a is a flat surface 24a of the control shaft 24. And the support piece 27 of the bracket 25 are fastened together by the bolts 30 and 30 so as to be integrated with the control shaft 24, the bracket 25 and the control eccentric shaft 26 and rotate around the base end 36a side. It is like that. Each arm member 36 can be formed in an elongated rod shape in addition to the flat plate shape.

  The biasing means 37 is slidably accommodated in a bottomed cylindrical body 38 held in a support hole (not shown) formed in the upper end portion of the cylinder head 05, and a sliding hole 38a of the body 38. And a coil spring 40 that is a spring member that is provided inside the bottom wall 38b of the body 38 and biases the plunger 39 in the advance direction.

  The body 38 has an opening 38c at the upper end, and a guide hole 38d is formed at a substantially central position of the bottom wall 38b.

  The plunger 39 is provided with a spherical tip 39a protruding from the opening 38c of the body 38 so as to be in contact with the lower surface of the arm member 36, and a small-diameter shaft whose outer periphery is notched cylindrically. The coil spring 40 is inserted and held on the outer periphery of the small diameter shaft portion 39b.

  Further, a shaft-shaped stopper portion 41 is fixed to the lower portion of the small-diameter shaft portion 39b of the plunger 39 from the axial direction. As shown in FIGS. 4 and 5, the stopper portion 41 is slidably guided in the guide hole 38d of the body bottom wall 38b, and the flange portion 41a on the tip side is formed on the outer hole edge of the guide hole 38d. At the time of contact, the maximum advance position of the plunger 39 is regulated.

  Therefore, in the state where the plunger 39 is advanced by the spring biasing force of the coil spring 40 and the maximum advanced position is regulated by the stopper portion 41, the tip 39a presses the arm member 36 as shown in FIG. Thus, the control shaft 24 is rotated in the clockwise direction in the figure. At the rotational position of the control shaft 24, the position of the flange portion 41a is set so that each of the intake valves 3 and 3 has a predetermined small lift suitable for starting the engine larger than the minute lift.

  Hereinafter, the operation of the variable valve operating apparatus of the present embodiment will be described.

  For example, in a low rotation range such as during idling operation of the engine, the electric motor 32 is rotationally driven by a control signal from the electronic controller 34, and the control shaft 24 is shown in FIG. 4, for example, via the ball screw mechanism 33 by this rotational torque. Thus, it is rotationally driven to a predetermined position in the counterclockwise direction. Therefore, the control eccentric shaft 26 is located at the same position and slightly moves downward from the drive shaft 4. As a result, the entire transmission mechanism 8 tilts clockwise about the drive shaft 4. For this reason, each rocking cam 7 also rotates clockwise, and the contact position of the roller 14 is closer to the base circle portion side of the cam surface 7c.

  Therefore, when the rocker arm 15 is pushed up via the link arm 16 as the drive cam 5 rotates, the connecting portion 7d of the rocking cam 7 is lifted via the link rod 17 and the rocking cam 7 is rotated in the clockwise direction. Is transmitted to the roller 14 of the swing arm 6 to lift the valve, but the lift amount and operating angle are sufficiently small, resulting in a minute lift and operating angle.

  Therefore, in the low rotation light load region of such an engine, the valve lift amount of each intake valve 3 becomes sufficiently small, thereby delaying the opening timing of each intake valve 3 and eliminating the valve overlap with the exhaust valve. For this reason, improvement in fuel consumption and stable engine rotation can be obtained by improving combustion.

  At this time, since the plunger 39 is pressed downward by the arm member 36, the plunger 39 moves backward against the spring force of the coil spring 40.

  Next, when the engine operating state shifts to the low / medium rotation / load range, the control shaft 24 is further rotated clockwise from the side shown in FIG. The eccentric shaft 26 also rotates to the same position and approaches the drive shaft 4.

  For this reason, the entire transmission mechanism 8 such as the rocker arm 15 and the link arm 16 rotates counterclockwise about the drive shaft 4, whereby the swing cams 7 and 7 are also relatively counterclockwise (lift direction). ).

  Therefore, when the peak lift is reached when the valve is opened, the lift of the swing cam 7 is transmitted to the needle roller 14 of the swing arm 6 and the valve lifts. However, the lift amount and the operating angle increase, and the intermediate lift and intermediate operating angle increase. become.

  Therefore, the valve lift amount and the operating angle of each intake valve 3 are increased in the region of low and medium rotation load of the engine, and fuel efficiency and torque can be improved.

  Further, for example, in the case of shifting to the engine high rotation / high load region, when the electric motor 32 further rotates the control shaft 24 in the clockwise direction via the ball screw mechanism 33 by the control signal from the electronic controller 34, FIG. As shown, the control eccentric shaft 26 also rotates in the same direction and moves to a position closest to the drive shaft 4.

  For this reason, the entire transmission mechanism 8 is further rotated counterclockwise, whereby the swing cams 7 and 7 are also relatively further rotated counterclockwise (lift direction). Therefore, when the peak lift is reached when the valve is opened, the lift of each swing cam 7 is transmitted to the roller 14 of the swing arm 6 to perform valve lift. However, the lift amount and the operating angle are further increased to increase the maximum lift and the maximum operation. Become a corner.

  Therefore, in such an operation region, the valve lift amount and the operating angle are maximized, the valve overlap with the exhaust valve is increased, and the closing timing is sufficiently delayed. As a result, the intake charging efficiency is improved and a sufficient output can be secured.

  When the ignition switch is turned off to stop the driving of the internal combustion engine 01, the power supply from the electronic controller 34 to the electric motor 32 is cut off. At this time, the swing cams 7 and 7 and the transmission mechanism 8 are stopped. In addition, an alternating torque is generated due to the spring force of the valve spring 10 or the like. Due to this alternating torque, a counterclockwise (minute lift direction) rotational force shown in FIG. 4 acts on the control shaft 24.

  Therefore, the arm member 36 of the holding mechanism 35 rotates together with the control shaft 24 in the counterclockwise direction between the intermediate lift and the intermediate operating angle to the maximum lift and the maximum operating angle. However, since the spring force of the coil spring 40 is made stronger than the alternating torque, the control shaft 24 stops rotating at a position where the spring force of the coil spring 40 starts to act. For this reason, the engine 01 can be reliably restarted.

  As a result, the distal end portion 39a of the plunger 39 pushes up the distal end portion 36b side of the arm member 36 to rotate the control shaft 24 in the clockwise direction, and is held at a predetermined rotational position, that is, a position regulated by the stopper portion 41. (See FIG. 5). Therefore, the intake valves 3 and 3 are held in a small lift state suitable for engine starting.

  Further, at this time, the contact position of the plunger tip end portion 39a with respect to the tip end portion 36b of the arm member 36 is the position farthest from the base end portion 36a at the position (minute lift position) shown in FIG. As it rises, the position approaches the proximal end portion 36a as shown in FIG. As described above, at the position farthest from the base end portion 36a, the arm member 36 can be rotated by the lever action, that is, the control shaft 24 can be rotated clockwise.

  Thereafter, as described above, after the internal combustion engine 01 is started, the control shaft 24 is shifted to the middle rotation or high load range so that the control shaft 24 rotates in the clockwise direction to the middle lift or the maximum lift. In this case, the arm member 36 is separated from the distal end portion 39a of the plunger 39, as shown by a one-dot chain line and a solid line in FIG. For this reason, the drive load with respect to the said electric motor 32 does not act.

  As described above, in the present embodiment, the rotational position of one control shaft 24 is controlled by the plurality of holding mechanisms 35 (biasing means) provided for each cylinder when the engine is stopped, and therefore, this embodiment is suitable for always starting. It is possible to stably hold the rotating position.

  In addition, for example, even when the engine is stopped due to a failure during a minute lift such as during the idling operation, the control shaft 24 can be quickly returned to the rotation position suitable for starting by the holding mechanism 35. Can also be fully demonstrated.

  Further, since the entire structure of the holding mechanism 35 is relatively simple, it is possible to suppress an increase in manufacturing cost.

  Furthermore, by restricting the protrusion amount of the plunger 39 more than necessary by the stopper portion 41, the load on the electric motor 32 that rotationally drives the control shaft 24 can be reduced.

  In addition, by setting the spring set load of each coil spring 40 appropriately small, it becomes possible to reduce the load of the electric motor 32 at the time of minute lift control.

[Second Embodiment]
FIGS. 7 to 10 show a second embodiment. In addition to the lift adjusting mechanism 21 that performs fine lift adjustment of the intake valves 3 and 3 between the cylinders by adjusting bolts when assembling the constituent members, FIGS. A second lift adjustment mechanism 29 that can adjust the lift amount in the lift control is provided.

  That is, in the variable valve system as in the first embodiment, the control shaft 24 and the control eccentric shaft 26 are separate from each other. If it differs depending on the cylinder, the lift amount, operating angle, and lift center angle phase of the intake valves 3 and 3 between the cylinders will vary. That is, when the lift adjusting mechanism 21 is not used, the actual lift characteristic (thin solid line) greatly changes from the minute lift region to the maximum lift with respect to the theoretical lift amount (thick solid line) as shown in FIG. It is clear that it will. As a result, a difference may occur in the amount of intake air into the combustion chamber, which may impair the operability and stability of the engine.

  Therefore, when the components are assembled by the lift adjusting mechanism 21, the length of the link rod 17 is adjusted to adjust the variation such as the minute lift amount.

  However, when the lift amount at the time of the minute lift posture of each component is adjusted by the lift adjustment mechanism 21, as shown in FIG. 12, the theoretical lift amount change characteristic due to the posture change of the control mechanism 9 ( The actual lift characteristics (thin solid line and broken line) with respect to the thick solid line) will cause a larger error in the lift amount as the lift amount is changed to the maximum lift posture side, and will be the largest in the maximum lift range. I understood.

  Therefore, in the present embodiment, as a method for adjusting the alignment of the control mechanism 9, the second lift adjustment mechanism 29 adjusts the eccentric amount α (distance) of the control eccentric shaft 26 with respect to the control shaft 24, thereby adjusting the lift amount. The error is eliminated.

  Hereinafter, a specific structure will be described. Since the basic structure including the lift adjusting mechanism 21 is the same as that of the first embodiment, common members are denoted by the same reference numerals and detailed description thereof is omitted. .

  That is, as shown in FIGS. 7 and 8, the control shaft 24 has a flat surface 24a formed at a position corresponding to each cylinder on the outer peripheral surface as in the first embodiment. On the other hand, the bracket 25 is formed in a substantially U-shape on the front side, the support piece 27 and the bracket pieces 28 and 28 are arranged on the same plane, and the control eccentric shaft 26 is fixedly supported at the tip portion. Support holes 28a and 28a are formed.

  The support piece 27 is formed in a substantially plate shape that is perpendicular to the bracket pieces 28, 28, and an arm member 36, which will be described later, is controlled at a substantially central position on one side edge of the bracket pieces 28, 28. A substantially L-shaped bent portion 27b that restricts further insertion of the arm member 36 when being interposed between the shaft 24 and the shaft 24 is integrally provided.

  Further, a pair of shaft insertion holes 42 and 42 through which the control shaft 24 is inserted are formed through the end portions of the bracket pieces 28 and 28 on the support piece 27 side. Each of the shaft insertion holes 42 and 42 is formed as a substantially oval long hole along the longitudinal direction of the bracket pieces 28 and 28.

  The arm member 36 is interposed between the inner surface of the support piece 27 of the bracket 25 and the flat surface 24a of the control shaft 24 on the base end 36a side, and is fixed together by the bolts 30 and 30. ing. The arm member 36 functions as an adjustment shim, and a plurality of members having different thicknesses t are prepared in advance.

  Therefore, according to this embodiment, when assembling the constituent members of the control mechanism 9, that is, in the gap between the flat surface 24 a of the control shaft 24 and the inner surface of the support piece 27 of the bracket 25, When inserting the base end portion 36a side and fixing with the bolts 30 and 30, by selecting and inserting any one of the arm members 36 having different plate thickness t, the bracket is inserted through the shaft insertion holes 42 and 42. 25 can be moved slightly in the radial direction with respect to the control shaft 24, that is, in the longitudinal direction of the bracket pieces 28, 28. As a result, the eccentric amount α up to the axis P1 of the control eccentric shaft 26 with respect to the axis P of the control shaft 24 is adjusted.

  In this case, when the plate thickness t of the arm member 36 is thick, the support piece 27 moves away from the control shaft 24 and the control eccentric shaft 26 approaches, so that the eccentric amount α decreases, and when the plate thickness t is thin, the support piece 27 Since 27 approaches the control shaft 24 and the control eccentric shaft 26 leaves, the amount of eccentricity α increases.

  According to this embodiment, since the amount of eccentricity α between the control shaft 24 and the control eccentric shaft 26 can be arbitrarily adjusted, the alignment of the control mechanism 9 can be adjusted. Therefore, the actual lift change characteristic (thin solid line in FIG. 13) from the minute lift control shown in FIGS. 9A and 9B to the maximum lift control shown in FIGS. 10A and 10B is the theoretical lift control as shown in FIG. The error is sufficiently reduced with respect to the change characteristic (thick solid line). As a result, in any case of the engine operation state, variations in lift of the intake valves 3 and 3 between the cylinders are eliminated, and the operability and stability of the engine are improved.

  Further, by inserting and sandwiching the arm member 36 in the gap between the control shaft 24 and the support piece 27, the force generated in the control eccentric shaft 26 due to torque fluctuations during engine driving or rocking movement of the rocker arm 15 is The bending moment of the axis P of the control shaft 24 of the bracket 25 is obtained. Since this bending moment is transmitted to the control shaft 24 via the arm member 36, the rotational force can be received by the flat surface 24a of the control shaft 24. For this reason, since a bending moment does not act on each volt | bolt 30 and 30, the improvement of durability of the volt | bolt 30 and 30 weak to this bending moment can be aimed at.

  In particular, the greater the amount of eccentricity α of the control eccentric shaft 26 with respect to the control shaft 24, the greater the change in the attitude of the variable mechanism, and the greater the variation in lift amount between the cylinders.

  In this embodiment, as shown in FIGS. 9 and 10, since the arm member 36 is provided in a standing state, the body 38 and the plunger 39 of the holding mechanism 35 are provided on the head cover 06 side. It has been.

  During minute lift control such as when the engine is idling, the distal end portion 36b of the arm member 36 presses the plunger 39 against the spring force of the coil spring 40, as shown in FIGS. 9A and 9B. However, when the engine is stopped, the plunger 39 moves forward to the maximum and presses the arm member 36 to control the control shaft 24 to the small lift side optimum for starting.

Further, in the middle engine load and the high load region, as shown in FIGS. 10A and 10B, the plunger 39 is separated from the arm member 36, so that the load of the electric motor 32 is suppressed. Therefore, the same effect as the first embodiment can be obtained.
[Third Embodiment]
14 and 15 show the third embodiment, in which the structure of the second lift adjustment mechanism 29 is changed. The bracket 25 has the same structure as that of the first embodiment, and each bracket through which the control shaft 24 is inserted. The shaft insertion holes 42, 42 of the pieces 28, 28 are formed in an oval shape along the longitudinal direction of each bracket piece 28, 28, and the bolt holes 43, 43 of the arm member 36 are also formed in the longitudinal direction of the arm member 36. It is formed in the shape of an oval long hole. A plurality of arm members 36 having different thicknesses t and distances u are prepared.

  Therefore, when assembling the constituent members of the holding mechanism 35, the bracket 25 and the control shaft 24 are in contact with the control shaft 24 in a state where the distal end of the base end portion 36 a of the arm member 36 abuts the bent portion 27 b of the support piece 27. The arm member 36 can adjust the distance u between the shaft center of the bolts 30 and 30 and the bracket 25 through the shaft insertion holes 42 and 42 and the long holes of the bolt holes 43 and 43. Thereafter, the bolts 30 and 30 are fixed. At this time, the arm member 36 having the optimum plate thickness t is selected in advance. In this case, when the distance u is shortened, the eccentric amount α is decreased, and when the distance u is increased, the eccentric amount α is increased. Further, when the plate thickness t of the arm member 36 is increased, the phase θ (= inclination angle) of the control eccentric shaft 26 with respect to the control shaft 24 is increased, and when the plate thickness t is decreased, the arm member 36 is decreased.

  In the case of this embodiment as well, the same effects as the second embodiment can be obtained, and in particular, since a large bending moment does not act on the bolts 30 and 30, the durability of the bolts 30 and 30 is improved.

  Further, during minute lift control such as during idling operation of the engine, the tip end portion 36b of the arm member 36 presses the plunger 39 against the spring force of the coil spring 40 as shown in FIGS. However, when the engine is stopped, the plunger 39 moves forward to the maximum and presses the arm member 36 to control the control shaft 24 to the small lift side optimum for starting.

Further, in the middle engine load and the high load region, as shown in FIGS. 15A and 15B, the plunger 39 is separated from the arm member 36, so that the load of the electric motor 32 is suppressed. Therefore, the same effect as the first embodiment can be obtained.

[Fourth Embodiment]
FIG. 16 shows a fourth embodiment in which a switching mechanism 46 for switching the forward and backward movement of the plunger 39 of the holding mechanism 35 is provided.

  The switching mechanism 46 includes an accommodation hole 47 formed in the upper end portion of the peripheral wall of the body 38 along the radial direction, a piston 48 that is a lock member slidably provided in the accommodation hole 47, and the plunger 39. An engagement hole 49 that is a lock hole to which the piston 48 can be engaged and disengaged, and a coil spring 50 that urges the piston 48 toward the engagement hole 49. The hydraulic circuit 51 is configured to move the piston 48 backward in the direction of the accommodation hole 47 against the spring force of the coil spring 50.

The housing hole 47 is formed through the peripheral wall of the body 38 from the radial direction, and the outer end opening is closed by a closing plate 53 fixed to the outer side surface of the body 38 by a bolt 52, and is drilled in the closing plate 53. The small diameter air holes 53a communicate with each other.
The air holes 53a ensure the slidability of the piston 48.

  The piston 48 has a length in the axial direction set slightly shorter than the length in the axial direction of the receiving hole 47, and the receiving hole is at the maximum retracted position where the rear end edge is in contact with the inner surface of the closing plate 53. 47 is accommodated so as to be completely buried.

  The piston 48 has a tip engaged with the engagement hole 49 by the spring force of the coil spring 50 at a position where the plunger 39 is retracted to the maximum in the sliding hole 38a. .

  The hydraulic circuit 51 is provided on the downstream side of the supply passage 55 by sucking oil in the oil pan 54 and discharging it to the supply passage 55, and supplies and discharges hydraulic pressure to the engagement hole 49. A supply / discharge passage 57; an electromagnetic switching valve 59 that selectively switches between the supply passage 55, the supply / discharge passage 57 and the drain passage 58; and the electronic controller 34 that outputs a control signal to the electromagnetic switching valve 59. ing.

  The oil in the oil pan 54 may be engine lubricating oil or separately dedicated oil, and the oil pump 56 is constituted by a trochoid type or vane type small pump.

  The supply / discharge passage 57 includes a main passage 57a formed in the cylinder head 05, a first oil hole 57a formed in a radial direction of the peripheral wall of the body 38 and connected to the main passage, and the plunger. The first oil hole 57a and the other end face the front end surface (pressure receiving surface) of the piston 48 through the receiving hole 47. 2 oil holes 57c.

  The electromagnetic switching valve 59 is a two-way two-position valve, and communicates the supply passage 55 and the supply / discharge passage 57 or closes the supply passage 55 according to a control signal output from the electronic controller 34. The flow path is switched and controlled so that the supply / discharge passage 57 and the drain passage 58 communicate with each other.

  Other configurations of the holding mechanism 35 and the arm member 36 are the same as those in the first embodiment.

  When the internal combustion engine 01 is normally driven, as shown in FIG. 16, the electromagnetic switching valve 59 closes the downstream end of the supply passage 5 by the control signal from the electronic controller 34 and the supply / discharge passage. 57 and the drain passage 58 are communicated with each other.

  For this reason, since no hydraulic pressure acts on the pressure receiving surface of the piston 48, the tip end portion of the piston 48 is engaged in the engagement hole 49 by the spring force of the coil spring 50 to restrict the advance movement of the plunger 39. Yes.

  On the other hand, when the control shaft 24 cannot be rotated due to a failure of the electric motor 32 or the like, in particular, the control shaft 24 is locked during the minimum lift control, that is, at the maximum counterclockwise rotation position in FIG. When 36 is in contact with the tip 39a of the plunger 39 (the chain line in FIG. 16), a control signal is output from the electronic controller 34 that detects this to the electromagnetic switching valve 59, The communication between the supply / discharge passage 57 and the drain passage 58 is blocked, and the supply / discharge passage 57 and the supply passage 55 are connected.

  As a result, the piston 48 is moved backward against the spring force of the coil spring 50 by the hydraulic pressure applied to the pressure receiving surface, and is entirely accommodated in the accommodation hole 47, and is engaged with the engagement hole 49. It is released and the movement of the plunger 39 is allowed.

  For this reason, as indicated by a two-dot chain line in the figure, the plunger 39 advances to the maximum until it is regulated by the stopper portion 41 by the spring force of the coil spring 40 and rotates the arm member 36 clockwise to the solid line position. Move. Therefore, the control shaft 24 controls the rotational position at which the internal combustion engine 01 can be operated, that is, the intake valves 3 and 3 to a predetermined lift amount and operating angle, thereby ensuring the traveling of the vehicle. Thus, the safety of the vehicle can be improved by exhibiting the fail-safe function.

  Further, when the electric motor 32 returns to a normal state, the electromagnetic intake valve switching valve 59 blocks the communication between the supply passage 55 and the supply / discharge passage 57, and the supply / discharge passage 57 and the drain passage 58. To communicate. For this reason, for example, when the engine 01 is stopped, the control shaft 24 rotates counterclockwise due to the alternating torque or the like, and the arm member 36 is rotated counterclockwise to the one-dot chain line to the maximum.

  Then, the plunger 39 moves backward to the maximum extent until its rear end edge shown in FIG. 16 abuts against the inner hole edge of the guide hole 38d, so that the accommodation hole 47 and the engagement hole 49 coincide. As a result, the piston 48 is advanced by the spring force of the coil spring 50, and the tip end portion engages with the engagement hole 49 to hold the plunger 39 at the maximum retracted position. For this reason, the plunger 39 is separated from the arm member 36 to avoid contact.

  As a result, the driving load of the electric motor 32 and the ball screw mechanism 33 that rotationally drive the control shaft 24 is eliminated, and a sufficient torque and quick driving are always obtained.

  The present invention is not limited to the configuration of the above-described embodiment, and the holding mechanism 35 can be provided not only in the entire cylinder but in, for example, only two cylinders positioned at both axial ends of the control shaft. .

  Further, the piston 48 can be moved forward and backward, not hydraulically. Further, it can be provided not only on the intake side but also on the exhaust side.

The technical ideas of the invention other than the claims ascertained from the embodiment will be described below.
[Claim a] The variable valve operating apparatus for an internal combustion engine according to claim 1,
The variable valve operating apparatus for an internal combustion engine, wherein the urging means is provided for each cylinder.
[Claim b] The variable valve operating apparatus for an internal combustion engine according to claim 2,
The variable mechanism is
A drive shaft to which rotational driving force is transmitted;
An eccentric shaft provided at a position eccentric from the rotation center of the control shaft;
A rocker arm that rotates about the eccentric shaft, wherein the rotational motion of the drive shaft is converted into a swing motion;
A rocking cam that opens and closes the engine valve by rocking when the rocking force of the rocker arm is transmitted,
A variable valve operating apparatus for an internal combustion engine, wherein the eccentric shaft is attached to the control shaft via a support member, and the biasing force of the spring member acts on the support member.
[Claim c] A variable valve operating apparatus for an internal combustion engine according to claim b,
The variable valve operating apparatus for an internal combustion engine, wherein the eccentric shaft is formed such that a position thereof can be adjusted to be separated from or close to the control shaft via the support member.
[Claim d] In the variable valve operating apparatus for an internal combustion engine according to claim c,
The support member includes a support portion that supports the eccentric shaft, and an adjustment shim interposed between the support portion and the control shaft,
The variable valve operating apparatus for an internal combustion engine, wherein an urging force of the spring member directly acts on the adjustment shim.

According to this invention, the number of parts can be reduced by sharing the members.
[Claim e] In the variable valve operating apparatus for an internal combustion engine according to claim 2,
A variable valve operating apparatus for an internal combustion engine, comprising a stopper portion for restricting a protruding amount of the plunger more than a predetermined amount.

According to this invention, it is possible to reduce the load of the actuator that rotationally drives the control shaft by restricting the protrusion amount of the plunger more than necessary by the stopper portion.
[Claim f] The variable valve operating apparatus for an internal combustion engine according to claim e,
The engine valve has an operating angle between a maximum operating angle and a minimum operating angle in a state in which the protrusion amount of the plunger is regulated by the stopper portion and the tip end portion is in contact with the arm member. A variable valve operating device for an internal combustion engine.
[Claim g] In the variable valve operating apparatus for an internal combustion engine according to claim 2,
An internal combustion engine comprising switching means capable of selectively switching between a state where the plunger is urged and advanced by the spring member and a state where the plunger is retracted against the urging force of the spring member. Variable valve gear.
(Claim h) In the variable valve operating apparatus for an internal combustion engine according to claim g,
The variable valve operating apparatus for an internal combustion engine, wherein the switching means includes a lock mechanism provided between the plunger and a sliding hole through which the plunger slides.
[Claim i] In the variable valve operating apparatus for an internal combustion engine according to claim h,
The lock mechanism includes a lock member provided on one of the plunger side and the sliding hole side, and a lock hole provided on the other side to which the lock member can be engaged and disengaged. The variable valve operating apparatus for an internal combustion engine is characterized in that the operation of is controlled electrically.
(Claim j) In the variable valve operating apparatus for an internal combustion engine according to claim i,
The variable valve operating apparatus for an internal combustion engine, wherein the lock member is configured to be retracted from the lock hole by hydraulic pressure, and the hydraulic pressure is controlled by a hydraulic control valve.
[Claim k] In the variable valve operating apparatus for an internal combustion engine according to claim 3,
The variable valve operating apparatus for an internal combustion engine, wherein the urging means is provided at least at both axial ends of the control shaft.
[Claim 1] In the variable valve operating apparatus for an internal combustion engine according to claim 3,
The variable valve operating apparatus for an internal combustion engine, wherein the urging means is provided at a symmetrical position about an axial center position of the control shaft.

1 ... Cylinder head 3 ... Intake valve (engine valve)
DESCRIPTION OF SYMBOLS 4 ... Drive shaft 5 ... Drive eccentric cam 7 ... Swing cam 8 ... Transmission mechanism 9 ... Control mechanism 15 ... Rocker arm 15a ... Cylindrical base part 15b ... 1st arm part 15c ... 2nd arm part 16 ... Link arm 17 ... Link rod DESCRIPTION OF SYMBOLS 18 ... Connecting pin 24 ... Control shaft 25 ... Bracket 26 ... Control eccentric shaft 27 ... Support piece 28 ... Bracket piece 30 ... Bolt 31 ... Electric actuator 32 ... Electric motor 33 ... Ball screw mechanism 35 ... Holding mechanism 36 ... Arm member 37 ... Biasing means 38 ... body 39 ... plunger 40 ... coil spring (biasing member)
41: Stopper 41a ... Flange 46 ... Switching mechanism

Claims (3)

A variable valve operating apparatus provided with a variable mechanism for each cylinder for varying the operating angle of the engine valve of each cylinder by controlling the rotation of the control shaft,
A variable valve operating apparatus for an internal combustion engine, characterized in that a plurality of urging means for urging the control shaft in the rotational direction in which the operating angle of the engine valve increases is provided at a plurality of locations in the axial direction of the control shaft. . A variable valve operating apparatus provided with a variable mechanism for each cylinder for varying the operating angle of the engine valve of each cylinder by controlling the rotation of a control shaft,
A plurality of arm members provided at a plurality of locations of the control shaft so as to protrude in the radial direction;
A plurality of plungers provided so that the control shaft can come into contact with the side surfaces in the swing direction of the arm members that increase the operating angle of the engine valve;
A spring member that applies a biasing force in a direction in which each plunger advances,
The distance between the contact portion of each plunger and each arm member and the rotation center of the control shaft is the longest at the rotation position of the control shaft where the operation angle of the engine valve is minimum, and the operation of the engine valve A variable valve operating apparatus for an internal combustion engine, wherein the variable valve operating apparatus is set to be shortened as the angle increases. A variable valve operating apparatus provided with a variable mechanism for each cylinder for varying the lift amount of the engine valve of each cylinder by controlling the rotation of the control shaft,
A plurality of urging means for urging the control shaft in a rotational direction in which the operating angle of the engine valve is increased;
A variable valve operating apparatus for an internal combustion engine, characterized in that the urging means is provided on at least both sides of an axial center position of the control shaft.

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