JP2013060858A - Variable valve gear for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a variable valve gear for an internal combustion engine which is reduced size and easily manufactured.SOLUTION: The variable valve gear for an internal combustion engine includes: a cylinder head 1 having a plurality of cylinders; a plurality of cam housings 15 disposed on an upper part of the cylinder head 1 to be positioned at both sides in a row direction of the respective cylinders; a camshaft 3 rotatably journaled to the cam housings 15; a cam carrier 4 which is fitted to the camshaft 3 and rotated together with the camshaft 3, and can be movable in the axial direction with respect to the camshaft 3; a low-speed cam 41 and a high-speed cam 42; and plungers 5 incorporated in the cam housings 15 and hydraulically driven to push out the cam carrier 4 in the axial direction to switch the cams.

Description

  The present invention relates to a variable valve operating apparatus for an internal combustion engine.

  2. Description of the Related Art Conventionally, a variable valve device for an internal combustion engine is known in which a spiral groove is formed on the lateral outer periphery of two types of large and small cams formed on a cam carrier for changing valve timing and lift amount. (For example, refer to Patent Document 1). This variable valve operating device is operated by inserting and removing a pin driven by an electric actuator such as a solenoid in a spiral groove from the radial direction of the cam carrier, and the cam carrier is pivoted with respect to the cam shaft in accordance with the operation. The cam is switched by moving in the direction.

Japanese Patent No. 4330618

  However, the conventional variable valve device described above requires a space for forming a spiral groove whose orbit changes in the cam shaft direction on the outer peripheral surface of the cam carrier. Therefore, when such a variable valve apparatus is employed, there is a problem that the overall length of the engine becomes long. In addition, since the electric actuator for inserting / removing the pin into / from the spiral groove needs to be arranged above the cam carrier in the cylinder head, there is a problem that the cylinder head becomes large. In addition, in such a variable valve operating apparatus, it is necessary to accurately form a spiral groove on the outer peripheral surface of the cam, which makes it difficult to manufacture and increases the cost.

  Further, in the conventional variable valve device described above, since the pin inserted into and removed from the spiral groove is electrically driven by the electric actuator, a separate drive circuit is required, which is disadvantageous in terms of cost and reliability. .

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a variable valve operating apparatus for an internal combustion engine that can be downsized and easily manufactured.

  In order to solve the above-described problems and achieve the object, one aspect of the present invention is a variable valve operating apparatus for an internal combustion engine, which includes a cylinder head having a plurality of cylinders arranged in a row, A plurality of cam housings provided at upper portions of the cylinder head so as to be positioned on both sides in the row direction of each cylinder, and a plurality of cams extending along the row direction above the plurality of cylinders The cam shaft rotatably supported by the housing and the cam housings adjacent to each other are arranged, fitted to the cam shaft and rotated integrally with the cam shaft, and the shaft relative to the cam shaft. A cam carrier that can move in the direction, and a common base circle that is provided adjacent to the outer peripheral surface of the cam carrier along the axial direction and that allows the cam carrier to move when contacting the valve side member. Or A plurality of cams each having a different nose portion, and a cam carrier that is built in each cam housing and presses the end face of the cam carrier facing the cam housing by hydraulic drive, and the cam carrier is moved along the axial direction to And an extrusion driving section for switching the cam.

  As said aspect, the 1st oil path connected to the group of the extrusion drive part which can press the end surface of one side of each cam carrier, and the group of the extrusion drive part which can press the other end surface of each cam carrier It is preferable to provide with the 2nd oil path connected to.

  As said aspect, it can be set as the structure currently formed so that the said 1st oil path and the said 2nd oil path may extend in the axial direction in a cam shaft.

  In the above aspect, the valve timing changing mechanism for advancing the valve timing by the hydraulic oil supplied through the advance oil passage and delaying the valve timing by the hydraulic oil supplied through the retard oil passage includes the camshaft. The plurality of cams include a first cam that relatively decreases the valve lift amount and a second cam that relatively increases the valve lift amount, from the second cam to the first cam. An oil passage for operating the push-out drive unit that performs the push-out operation for switching is communicated with the oil passage for advancement, and an oil for operating the push-out drive unit that performs the push-out operation for switching from the first cam to the second cam It is good also as a structure which connects a path | route with the said oil delay path.

  In the above aspect, an end cam surface having an axial height difference is formed around the end surface of the cam carrier so that the push driving portion extends along the axial direction of the cam shaft. It is good also as a structure which has a movable part which can be projected / recessed toward this, and when this movable part protrudes, the said end cam surface can contact the front-end | tip of the said movable part.

  According to the variable valve operating apparatus for an internal combustion engine according to the present invention, it is possible to realize a variable valve operating apparatus for an internal combustion engine that can be downsized and easily manufactured.

FIG. 1 is a cross-sectional view of a cylinder head provided with a variable valve operating apparatus for an internal combustion engine according to an embodiment of the present invention. FIG. 2 is a perspective view of a cylinder head provided with a variable valve operating apparatus for an internal combustion engine according to an embodiment of the present invention. 3 is a cross-sectional view taken along the line III-III in FIG. 4 is a cross-sectional view taken along the line IV-IV in FIG. 5 is a cross-sectional view taken along the line VV in FIG. FIG. 6 is a perspective view of a portion focusing on one cam carrier in the variable valve operating apparatus for an internal combustion engine according to the embodiment of the present invention. FIG. 7 is an exploded perspective view of a portion focusing on one cam carrier in the variable valve operating apparatus for an internal combustion engine according to the embodiment of the present invention. FIG. 8 is a perspective view showing a portion focused on one cam carrier in the variable valve operating apparatus for an internal combustion engine according to the embodiment of the present invention, and showing a state in which the plunger is built in the lower cam housing. FIG. 9 is a perspective view showing a part of the camshaft in the variable valve operating apparatus for the internal combustion engine according to the embodiment of the present invention. FIG. 10A is a cross-sectional view showing a state where the base circle portion of the high-speed cam (second cam) is in contact with the pressed roller of the rocker arm, taken along line XX in FIG. 8. FIG. 10-2 is a cross-sectional view showing a state where the nose portion of the high-speed cam is in contact with the pressed roller of the rocker arm, taken along line XX in FIG. FIG. 10C is a cross-sectional view showing a state where the piston of the plunger is protruded in the state shown in FIG. 10-4 shows that the cam carrier rotates in the state of FIG. 10-3 and the cam carrier moves by the action of the end cam surface and the piston, and the base circle of the low-speed cam contacts the pressed roller of the rocker arm. It is sectional drawing which shows the state cut | disconnected by the XX line of FIG. 8 which shows a state. 10-5 shows a state where the cam carrier rotates in the state shown in FIG. 10-4 and the nose portion of the low-speed cam is in contact with the pressed roller of the rocker arm, and is cut along line XX in FIG. FIG.

  Details of a variable valve operating apparatus for an internal combustion engine according to an embodiment of the present invention will be described below with reference to the drawings.

(Schematic configuration of variable valve operating device)
As shown in FIGS. 1-5, the variable valve operating apparatus 2 of the internal combustion engine which concerns on embodiment of this invention is incorporated in the cylinder head 1 of the engine as an internal combustion engine. As shown in FIG. 1, the cylinder head 1 includes a head body 1A and a head cover 1B. FIG. 2 is a perspective view showing a state in which the head cover 1B of the cylinder head 1 is removed.

  The head body 1A is provided with, for example, an upper portion of a cylinder 1C formed so as to form a line in the front-rear direction. A pair of intake valves 13 are provided above the cylinder 1C so as to be able to advance and retract in the axial direction by a valve guide (not shown). The intake valve 13 is urged by a valve spring 14 in a pulling direction (a direction in which the intake port and the cylinder 1C are closed). In addition, a pair of exhaust valves is provided at the upper portion of the cylinder 1C in the same manner as the intake valve 13. In the present embodiment, the direction of the row of cylinders 1C will be described as the front-rear direction of the vehicle for convenience of explanation. However, the variable valve operating apparatus for an internal combustion engine according to the present invention is limited to such a direction and arrangement. It is not something.

  The variable valve operating apparatus 2 for an internal combustion engine according to the present embodiment includes a cylinder head 1 having a plurality (three in this embodiment) of cylinders 1C, and an upper portion (head body 1A) of the cylinder head 1 respectively. A plurality of cam housings 15 provided on both sides in the row direction of the cylinders 1C so as to sandwich the cylinders 1C, and a plurality of cam housings extending above the plurality of cylinders 1C along the front-rear direction. 15, camshaft 3 rotatably supported by camshaft 15, cam carrier 4 arranged between cam housings 15 adjacent to each other, and each cam housing 15. A plurality of push driving units that switch the cams that actuate the valves by pressing the end surfaces of the opposing cam carriers 4 and moving the carrier 4 along the axial direction. It is schematically configured to include the plunger 5. The variable valve operating apparatus 2 according to the present embodiment includes a valve timing changing mechanism 70 that is connected to the camshaft 3 and changes the valve lift timing. However, the present invention includes the valve timing changing mechanism 70. There may be no configuration.

  The cam housing 15 is disposed at a position that does not overlap the cylinder 1C. As shown in FIG. 1 and FIG. 2, the cam housing 15 is formed by joining a lower cam housing 6 and an upper cam housing 7 installed on the head body 1 </ b> A. The lower cam housing 6 and the upper cam housing 7 are rotatably supported with the cam shaft 3 interposed therebetween. The upper cam housing 7 is fastened to the lower cam housing 6 with bolts 16. The lower cam housing 6 and the upper cam housing 7 are covered with a head cover 1B and built in the cylinder head 1.

  Here, the configuration of the variable valve operating apparatus 2 will be described using the main part located between the cam housings 15. As shown in FIGS. 6 to 8, the variable valve apparatus 2 includes a cam shaft 3, a cam carrier 4 in which a low speed cam 41 and a high speed cam 42 are provided adjacent to each other, and a cam carrier 4. And a pair of plungers 5 as extrusion driving portions disposed opposite to each other. In the present embodiment, the variable valve operating apparatus 2 as a whole includes three cam carriers 4 on the cam shaft 3 on the intake side, and three pairs (six) for pressing both end surfaces of the three cam carriers 4. The plunger 5 is provided.

  Such a variable valve apparatus 2 switches between the low speed cam 41 and the high speed cam 42 in order to change the lift state of the intake valve 13. Further, as shown in FIG. 1, the cylinder head 1 is further provided with a cam shaft 30 on the exhaust valve side, an exhaust cam 40, and the like.

  As shown in FIGS. 1, 6, and 7, in the present embodiment, a rocker arm 11 is used as a valve side member that swings with the rotation of the cam carrier 4. The rocker arm 11 is disposed such that a recess formed on the lower surface of the one end 11C abuts on the pivot 12A. In other words, the rocker arm 11 is supported by a pivot 12A that is a swing center (fulcrum) on the one end 11C side. The pivot 12A is provided on the cylindrical pivot support 12 so as to be adjustable.

  At the center of the rocker arm 11, a pressed roller 11A is pivotally supported by a pin 11B. The pressed roller 11 </ b> A protrudes from the upper surface of the rocker arm 11 and comes into contact with either the low speed cam 41 or the high speed cam 42 of the cam carrier 4. The lower surface of the arm tip 11D on the other end side of the rocker arm 11 is in contact with the upper end of the intake valve 13. In the present embodiment, the lower surface of the arm tip portion 11D is in contact with the upper end of the intake valve 13, but the valve clearance adjuster may naturally protrude from the lower surface of the arm tip portion 11D.

(Cam shaft)
For example, as shown in FIGS. 4 and 8, the camshaft 3 is rotatably supported by the lower cam housing 6 and the upper cam housing 7 which are the bearing portions disposed on the head main body 1A as described above. ing. As shown in FIG. 4, a camshaft timing sprocket 71 is provided at one end of the camshaft 3, and rotates in conjunction with a crankshaft (not shown) by a chain (not shown). The rotational speed of the camshaft 3 is set to be ½ of the rotational speed of the crankshaft, for example.

  As shown in FIG. 9, the camshaft 3 has a cylindrical shape, and is formed with a first oil passage 34 and a second oil passage 33 that are formed along the axial direction and are partitioned from each other. Further, spline external teeth 31 having a predetermined width dimension in the axial direction are formed around the central outer peripheral surface of the cam shaft 3 in a region sandwiched between the cam housings 15. A flat portion 32 that is flat along the axial direction is formed in a part of the spline outer teeth 31. At two central positions of the flat portion 32, concave portions 32A and 32B for positioning the cam carrier 4 are formed along the axial direction with a predetermined distance therebetween.

  As shown in FIG. 9, a first oil groove 36 and a second oil groove 35 are formed around both sides in the axial direction of the region where the spline external teeth 31 are formed in the camshaft 3. As shown in FIG. 8, the region where the first oil groove 36 and the second oil groove 35 are formed in the camshaft 3 is freely rotatable in the bearing portion between the lower cam housing 6 and the upper cam housing 7 described above. It is supported by.

  As shown in FIG. 10A, a communication hole 34 </ b> A that communicates with the first oil passage 34 is formed in the first oil groove 36. A communication hole 33 </ b> A that communicates with the second oil passage 33 is formed in the second oil groove 35. As shown in FIG. 10A, the first oil groove 36 is formed so as to communicate with the hydraulic chamber 54 of the plunger 5 (5A) from which the piston 51 protrudes in the left direction in the drawing. The second oil groove 35 is formed so as to communicate with the hydraulic chamber 54 of the plunger 5 (5B) from which the piston 51 projects rightward in the drawing.

  Thus, the plunger 5 is set so that those in which the pistons 51 protrude in the same direction communicate with the same oil passage. Specifically, as shown in FIG. 4, a group (three) of plungers 5 (5A) projecting in the direction in which the camshaft timing sprocket 71 is provided at the end of the camshaft 3 is the first The hydraulic chamber 54 is set to communicate with the oil passage 34 in common. On the other hand, the group (three) of plungers 5 (5B) projecting rightward in FIG. 10A is set so that the hydraulic chamber 54 communicates with the second oil passage 33 in common. The first oil groove 36 and the second oil groove 35 also have a function of supplying lubricating oil to the bearing portion between the lower cam housing 6 and the upper cam housing 7 shown in FIG.

(Cam carrier)
As shown in FIG. 7, the cam carrier 4 is formed in a cylindrical shape so as to surround the cam shaft 3. On the inner peripheral surface of the cam carrier 4, spline inner teeth 45 that mesh with the spline outer teeth 31 of the cam shaft 3 are formed. For this reason, the cam shaft 3 and the cam carrier 4 rotate together, and the cam carrier 4 can move in the axial direction with respect to the cam shaft 3.

  As shown in FIGS. 6 to 8, the cam carrier 4 has a valve operating characteristic on the peripheral surface and a low speed cam 41 as a first cam that relatively decreases the valve lift amount, and a relatively large valve lift amount. A high-speed cam 42 as a second cam is integrally provided side by side in the axial direction. In the present embodiment, a pair of intake valves 13 are arranged for the cylinder 1C. For this reason, as shown in FIGS. 6 to 8, a pair of the low-speed cam 41 and the high-speed cam 42 is arranged at a predetermined interval in the cam carrier 4 so as to correspond to each intake valve 13. Has been. When a pair of low-speed cams 41 and 41 is selected, each low-speed cam 41 is positioned above each intake valve 13 (rocker arm 11), and when a pair of high-speed cams 42 is selected, The intervals between the low-speed cams 41, the intervals between the high-speed cams 42, and the intervals between the intake valves 13 are set to be the same so that the high-speed cams 42 are positioned above the respective intake valves 13 (rocker arms 11). Yes.

  As shown in FIG. 8, the low-speed cam 41 includes a base circle portion 41A that serves as a foundation, and a nose portion 41B that protrudes radially outward from the base circle portion 41A. The high-speed cam 42 protrudes from the nose portion 41B of the low-speed cam 41 toward the outer side in the radial direction from the base circle portion 42A and the base circle portion 42A having the same radius as the base circle portion 41A of the base low-speed cam 41. And a formed nose portion 42B. As shown in FIG. 8, the low-speed cam 41 and the high-speed cam 42 are disposed adjacent to each other along the axial direction. Moreover, these base circular portions 41A and 42A are continuous surfaces formed flush with each other in the axial direction. Further, the nose portions 41B and 42B of the low-speed cam 41 and the high-speed cam 42 are arranged in a direction having substantially the same phase. In the present embodiment, the low-speed cam 41 and the high-speed cam 42 can advance or retard the lift timing of the intake valve 13 by a valve timing changing mechanism 70 described later.

  Further, an end cam surface 43 having a height difference in the axial direction is formed on the end surface in the axial direction of the cam carrier 4 so as to circulate and continue. The end cam surface 43 is opposed to the tip of a piston 51 as a movable part of the plunger 5 that reciprocates along the cam shaft direction. The cam carrier 4 moves in the cam shaft direction when the end cam surface 43 is pressed by the piston 51 of the plunger 5. Note that the tip of the piston 51 of the plunger 5 is operated to move in and out between two points of the most protruding position and the most retracted position.

  As shown in FIG. 8, the end cam surface 43 includes a non-drive portion 43A having a low cam height in the axial direction, a maximum drive portion 43B having the highest cam height in the axial direction, and a rotation direction of the maximum drive portion 43B. Drive units 43C and 43D located in front of and behind. The drive unit 43C is located on the front side in the rotation direction a of the cam carrier 4 with respect to the maximum drive unit 43B. The drive unit 43D is located on the rear side in the rotation direction a of the cam carrier 4 with respect to the maximum drive unit 43B. And the drive part 43C of the front side of the rotation direction a is set more gently than the drive part 43D.

  As shown in FIG. 7, a through hole 44 </ b> A for providing a click moving member is formed in the intermediate portion 44 of the cam carrier 4 so as to penetrate in the radial direction of the cam carrier 4. The through hole 44A has a ball 8 as a click moving member, a spring 9 that urges the ball 8 so as to protrude from the inner peripheral surface of the cam carrier 4 toward the central axis, and a through hole 44A. And a plug 10 that supports the outer end of the spring 9. When the cam carrier 4 moves in the axial direction with respect to the cam shaft 3, the ball 8 is engaged with the recesses 32A and 32B provided on the cam shaft 3 side with a click operation for positioning. ing.

(Plunger)
As shown in FIG. 8, the plunger 5 is built in the lower cam housing 6. FIG. 8 shows only the lower cam housing 6 in which one of the plungers 5A and 5B is built, but the other plunger 5A is also built in the lower cam housing 6 in the same manner. As shown in FIGS. 10-1 to 10-5, the lower cam housing 6 houses the piston 51 of the plunger 5, and is formed with a piston sliding hole 6A through which the piston 51 can move in the axial direction. The piston 51 is urged by a spring 52 in the direction of sunk in the piston sliding hole 6A.

  The plunger 5 causes the piston 51 to protrude and retract from the piston sliding hole 6 </ b> A by supplying and discharging oil from an actuator (not shown) to the hydraulic chamber 54 between the head of the piston 51 and the plug 53. ing. The piston 51 presses the cam carrier 4 and is driven at an appropriate switching timing so that either the low speed cam 41 or the high speed cam 42 corresponds to the rocker arm 11. As described above, the group (three) of the plungers 5 </ b> A from which the pistons 51 protrude in the same direction is formed so as to communicate with the first oil passage 34. A group (three) of plungers 5 </ b> B protruding in the opposite direction is formed so as to communicate with the second oil passage 33.

(Valve timing changing mechanism)
As shown in FIG. 4, the valve timing changing mechanism 70 includes an actuator 72 provided outside the camshaft timing sprocket 71 and a retarding oil passage communicating with a retarding hydraulic chamber 73 provided in the actuator 72. 76, an advance oil passage 75 communicating with an advance hydraulic chamber 74 provided in the actuator 72, an oil control valve 77, a solenoid 78 for operating the oil control valve 77, an oil pump, and an oil A pan 79 is provided.

  The oil control valve 77 is controlled by an engine control unit (hereinafter referred to as ECU) 80. The oil control valve 77 communicates the supply port with the advance oil passage 75, the first valve 77 position A, the second valve position 77B that shuts off the supply port and the discharge port, and the supply port with the retard oil passage 76. The third valve position 77C is switched by the operation of the solenoid 78. The solenoid 78 is controlled by the ECU 80.

  As shown in FIG. 4, in the present embodiment, the first oil passage 34 for operating the group of plungers 5 </ b> A that are switched from the high-speed cam 42 to the low-speed cam 41 is communicated with the advance oil passage 75. The second oil passage 33 for operating the group of plungers 5 </ b> B to be switched to the high-speed cam 42 is communicated with the retarded oil passage 76. For this reason, when using the low speed cam 41 having a relatively small valve lift, the oil control valve 77 is set to the first valve as shown in FIG. 4 so as to send oil to the hydraulic chamber 54 of the group of plungers 5A. What is necessary is just to set to the position 77A. In this case, the camshaft 3 can be advanced by supplying oil to the advance hydraulic chamber 74 and driving a vane (not shown). Therefore, the low-speed cam 41 formed on the cam carrier 4 that rotates integrally with the camshaft 3 can advance the valve timing as compared with the case where the high-speed cam 42 having a relatively large valve lift amount is used. The effect of reducing pump loss due to the intake resistance of the internal combustion engine is increased.

  Conversely, when switching from the low speed cam 41 to the high speed cam 42, the supply port is set to the third valve position 77C communicating with the retarded oil passage 76 so as to send oil to the hydraulic chambers 54 of the plunger 5B group. do it. In this case, oil is supplied to the retarding hydraulic chamber 73, the vane (not shown) is returned, the camshaft 3 is retarded, and the high-speed cam 42 is retarded accordingly, and the valve lift characteristic is obtained in the case of a large lift. Appropriate operation can be performed.

(Operation and operation of variable valve system)
Hereinafter, the operation of switching the low speed cam 41 and the high speed cam 42 of the variable valve operating apparatus 2 according to the present embodiment will be described with reference to FIGS. 10-1 to 10-5. FIGS. 10-1 to 10-5 are cross-sectional views showing the states of the variable valve operating device cut along line XX in FIG.

  FIG. 10A shows a state where the high speed cam 42 is selected and operated in the variable valve operating apparatus 2. At this timing, the base circle portion 42A of the high-speed cam 42 and the pressed roller 11A of the rocker arm 11 are in contact with each other. In such a state where the high-speed cam 42 is selected, the ball 8 which is a positioning means for performing the click operation is engaged with the recess 32A provided on the cam shaft 3 side for positioning.

  FIG. 10-2 shows that the nose portion 42B presses the pressed roller 11A of the rocker arm 11 and lifts the valve 13 (large lift) when the cam carrier 4 rotates while the high-speed cam 42 is selected. It shows the state.

  Next, when switching from the state in which the high speed cam 42 is selected as shown in FIG. 10-2 to the state in which the low speed cam 41 is selected, the solenoid 80 is controlled by the ECU 80 as shown in FIG. The first valve 77 is set to position A, the supply port is communicated with the advance oil passage 75, oil is supplied to the first oil passage, the volume of the hydraulic chamber 54 of the group of plungers 5A is increased, and the piston 51 is protruded. The state shown in FIG. As shown in FIG. 10-3, at this time, the tip of the piston 51 is at a position closest to the non-drive portion 43 </ b> A of the end cam surface 43.

  When the cam carrier 4 rotates in this state, the base circle portion 42A starts to contact the pressed roller 11A. Along with this, the drive part 43C and the maximum drive part 43B on the front side in the rotational direction of the end cam surface 43 slide with the tip part of the piston 51, so that the cam carrier 4 is moved from the tip part of the piston 51 whose position is fixed. Due to this reaction, the maximum drive unit 43B moves by about the height dimension in the axial direction. As a result, the base circle portion 41A of the low-speed cam 41 contacts the pressed roller 11A, and the cam is switched. At this time, since the vane (not shown) of the advance hydraulic chamber 74 is driven, the low-speed cam 41 has an advanced valve lift characteristic, and has the effect of reducing the pump loss as described above.

  In the present embodiment, the end cam surfaces 43 having a difference in height in the axial direction are formed at both ends of the cam carrier 4, so that the maximum protrusion length of the piston 51 of the plunger 5 can be reliably reduced. Cam switching can be performed. Therefore, the internal combustion engine can be downsized by suppressing the protruding length of the piston 51 of the plunger 5.

  Thus, when the cam carrier 4 is displaced with respect to the cam shaft 3, the ball 8 engaged with the recess 32A of the cam shaft 3 is disengaged from the recess 32A, and as shown in FIG. Move to engage. As a result, the cam carrier 4 is fixed to the cam shaft 3 at a position where the low speed cam 41 is selected.

  As shown in FIG. 10-5, in order to switch from the state in which the low speed cam 41 contacts the pressed roller 11A to the high speed cam 42, as shown in FIG. The supply port may be communicated with the retarded oil passage 76 at the valve position 77C. That is, by discharging the oil in the first oil passage 34 and supplying the oil to the second oil passage 33, the piston 51 of the plunger 5A on the right side in FIG. 51 can be protruded. At this time, since oil is supplied to the retarding hydraulic chamber 73, the camshaft 3 is retarded and the valve lift characteristic of the high-speed cam 42 can be brought into an appropriate state.

  In the variable valve operating apparatus 2 according to the present embodiment, the drive unit 43C on the front side in the rotational direction a of the end cam surface 43 of the cam carrier 4 has a gentler gradient than the drive unit 43D on the rear side in the rotational direction a. Since it is set, when the end cam surface 43 slides with respect to the tip of the piston 51, the lateral force received from the end cam surface 43 with respect to the piston 51 can be reduced. The operation reliability can be improved.

  In the present embodiment, the piston 51 of the plunger 5 is configured to reciprocate in the axial direction of the cam shaft 3, and the piston 51 presses the end cam surface 43 formed on the end surface of the cam carrier 4, thereby The carrier 4 is moved in the axial direction to switch between the high speed cam 42 and the low speed cam 41. Therefore, in the variable valve apparatus 2 according to the present embodiment, the piston is spirally formed on the outer peripheral surface of the cam carrier using a plunger whose piston reciprocates in the radial direction of the cam carrier 4 as in the conventional variable valve apparatus. Compared with the configuration in which the piston is inserted into and removed from the groove formed in the above, the height of the cylinder head 1 can be suppressed and the overall length of the cam carrier 4 can be shortened, and the internal combustion engine can be downsized. effective.

  In the variable valve operating apparatus 2 according to the present embodiment, the piston 51 of the plunger 5 is reciprocated in the same direction as the moving direction of the cam carrier 4, so that the driving force can be transmitted efficiently. Furthermore, in the present embodiment, the plunger 5 can be disposed at a low position in the height direction of the cylinder head 1, so that the cylinder head 1 can be reduced in size.

  In the variable valve apparatus 2 according to the present embodiment, since the plunger 5 is built in the cam housing (the lower cam housing 6 and the upper cam housing 7), the number of parts such as attachment members can be reduced.

  In the present embodiment, it is not a configuration in which the tip of the piston 51 is put in and out of the groove, but it is only necessary to reciprocate the piston 51 along the axial method on the end cam surface 43, so that the timing control can be simplified. it can. Furthermore, in this embodiment, since it is not necessary to form a spiral groove, the processing of the cam carrier 4 is facilitated, and the manufacturing efficiency of the variable valve apparatus 2 can be increased.

  In this embodiment, as shown in FIG. 10-4, when the cam carrier 4 is pushed out by the piston 51 of the plunger 5 and the low speed cam 41 is selected, the cam shaft 3 and the cam carrier 4 rotate. Therefore, if there is a slight clearance between the maximum drive part 43B of the cam carrier 4 and the tip part of the piston 51, the friction between the maximum drive part 43B and the tip part of the piston 51, abnormal noise, etc. are generated. Can be suppressed.

(Other embodiments)
Although the embodiment has been described above, it should not be understood that the description and the drawings constituting a part of the disclosure of the embodiment limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

  For example, when the base circular portions 41A and 42A come into contact with the pressed roller 11A of the rocker arm 11, for example, the drive portion 43C and the maximum drive portion 43B are disposed on the end cam surface 43 facing the piston 51 of the plunger 5. When the nose portions 41B and 42B come into contact with the pressed roller 11A, the non-driving portion 43A is formed on the end cam surface 43 facing the piston 51 of the plunger 5, and the driving portion 43C is connected to the maximum driving portion 43B. Any configuration may be used as long as it is formed between the non-driving unit 43A. Therefore, in the present invention, a plurality of cam carriers 4 are provided on one camshaft 3, but the arrangement position of the piston 51 of the plunger 5 in consideration of the balance of cam operation and valve operation in the plurality of cylinders 1C. The end cam surface 43 may be designed according to the above.

DESCRIPTION OF SYMBOLS 1 Cylinder head 2 Variable valve operating apparatus 3 Cam shaft 4 Cam carrier 5 Plunger (extrusion drive part)
6 Lower cam housing 6A Piston sliding hole 7 Upper cam housing 11 Rocker arm (valve side member)
11A Pressed roller (valve side member)
13 Intake valve (valve)
15 cam housing 33 second oil passage 34 first oil passage 33A, 34A communication hole 35 second oil groove 36 first oil groove 41 low speed cam (first cam)
42 High-speed cam (second cam)
43 End cam surface 43A Non-driving part 43B Maximum driving part 43C, 43D Driving part 51 Piston (movable part)
52 Spring 53 Plug 54 Hydraulic chamber 70 Valve timing changing mechanism 71 Camshaft timing sprocket 72 Actuator 73 Delay angle hydraulic chamber 74 Advance angle hydraulic chamber 75 Advance angle oil path 76 Delay angle oil path 77 Oil control valve 77A First valve position 77B Second valve position 77C Third valve position 78 Solenoid 79 Oil pan 80 Engine control unit (ECU)

Claims (5)

A cylinder head having a plurality of cylinders arranged in rows;
A plurality of cam housings provided on the upper part of the cylinder head so as to be positioned on both sides in the direction of the row in each of the cylinders;
A camshaft extending along the direction of the row above the plurality of cylinders and rotatably supported by the plurality of cam housings;
A cam carrier disposed between the cam housings adjacent to each other, fitted to the cam shaft, rotated integrally with the cam shaft, and movable in the axial direction with respect to the cam shaft;
A nose having a common base circular portion that is provided adjacent to the outer peripheral surface of the cam carrier along the axial direction and that allows the cam carrier to move when contacted with a valve-side member. A plurality of cams having a portion;
An extrusion drive unit built in each of the cam housings, pressing an end face of the cam carrier facing the cam housing by hydraulic drive, and moving the cam carrier along an axial direction to switch the cam;
A variable valve operating apparatus for an internal combustion engine, comprising:   A first oil passage communicating with the group of push drive units capable of pressing the end surface on one side of each cam carrier, and a push drive unit capable of pressing the end surface on the other side of each cam carrier. The variable valve operating apparatus for an internal combustion engine according to claim 1, further comprising a second oil passage communicating with the group.   The variable valve operating apparatus for an internal combustion engine according to claim 2, wherein the first oil passage and the second oil passage are formed in the camshaft so as to extend in an axial direction. A valve timing changing mechanism for advancing the valve timing with hydraulic oil supplied through the advance oil passage and delaying the valve timing with hydraulic oil supplied through the retard oil passage is connected to the camshaft,
The plurality of cams includes a first cam that relatively decreases a valve lift amount, and a second cam that relatively increases a valve lift amount,
Extrusion operation for switching from the first cam to the second cam by communicating an oil passage for operating the push drive unit that performs the push-out operation for switching from the second cam to the first cam with the advance oil passage 4. The variable valve operating apparatus for an internal combustion engine according to claim 3, wherein an oil passage for operating the push-out drive unit that performs the communication is communicated with the retarding oil passage. An end cam surface having an axial height difference is formed on the end surface of the cam carrier so as to go around.
The push driving unit has a movable part that can be projected and retracted toward the end cam surface along the axial direction of the cam shaft, and when the movable part protrudes, the end cam surface is the movable part. 5. The variable valve operating apparatus for an internal combustion engine according to claim 1, wherein the variable valve operating apparatus can be in contact with the tip of the internal combustion engine.

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