JP2017002766A - Variable valve device of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the responsiveness of the control of a cam blower member, in a variable valve device of an internal combustion engine having the cam blower member which is movable with respect to a cam base member.SOLUTION: A variable valve device 1 of an internal combustion engine comprises a cam base member 10 which rotates following the rotation of a camshaft S, and a cam blower member 12 which is movable with respect to the cam base member. A fixing element 26A for fixing the cam blower member 12 to the cam base member 10 is moved by a switching device 40 between an engagement position which is engaged with the cam blower member and a release position for releasing the cam blower member. The switching device 40 comprises a drive element 42 which is arranged outside the cam base member 10 in a radial direction, and an electric actuator 44 for moving the drive element. By an operation of the electric actuator 44, the drive element acts on a salient part 26b of the fixing element 26, and can move the fixing element 26.SELECTED DRAWING: Figure 1

Description

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

  2. Description of the Related Art Conventionally, a mechanism or device that makes an engine valve lift variable is known. Patent Document 1 discloses a camshaft of an automobile engine provided with a cam base member provided with a first cam portion directly and a cam lobe member provided with a second cam portion that can move in the radial direction with respect to the cam base member. Is disclosed. The cam lobe member changes the pressure of the supplied oil at one of a protruding position moved radially outward with respect to the cam base member and a retracted position moved radially inward with respect to the cam base member. Thus, it is selectively fixed and is always biased to the protruding position by a spring.

JP 2006-526727 A

  By the way, the viscosity of engine oil generally changes according to temperature. That is, at the cold start, the viscosity of the engine oil is relatively high. Therefore, the camshaft of Patent Document 1 has a problem in responsiveness in the hydraulic system for fixing the cam lobe member at the time of cold start and after completion of warm-up.

  An object of the present invention is to improve control responsiveness of a cam lobe member in a variable valve operating apparatus for an internal combustion engine including a cam lobe member movable with respect to a cam base member.

According to one aspect of the invention,
A variable valve operating apparatus for an internal combustion engine that makes the lift amount of an engine valve variable,
A cam base member provided on the cam shaft and rotating according to the rotation of the cam shaft;
A cam lobe member having a main cam portion between the first position where the main cam portion projects radially from the cam base member and the second position where the main cam portion does not project from the cam base member. A cam lobe member movable with respect to,
A biasing member that biases the cam lobe member against the cam base member, the biasing member biasing the cam lobe member toward one of the first position and the second position. An urging member provided;
A fixing element for fixing the cam lobe member in the first position to the cam base member, the fixing element engaging the cam lobe member so as to fix the cam lobe member to the cam base member. The locking element is movable in the axial direction of the camshaft between a mating engagement position and a release position for releasing the cam lobe member so that the cam lobe member can move relative to the cam base member; A fixing element having a portion and a projecting portion projecting radially from the main body portion;
A switching device for switching the position of the fixed element between the engagement position and the release position, the switching device including a drive element disposed radially outward of the cam base member, and the drive element An electric actuator for moving the drive element, and the drive element includes a switching device that acts on the protrusion to move the fixed element.
A variable valve operating apparatus for an internal combustion engine is provided.

  According to the one aspect of the present invention, the driving element moved by the electric actuator acts on the protrusion, so that the fixing element is moved between the engagement position and the release position, whereby the cam lobe member is moved to the cam base member. It becomes fixed or can move with respect to. That is, the position of the cam lobe member relative to the cam base member can be controlled with higher accuracy by moving the drive element by the electric actuator. Therefore, according to one aspect of the present invention, an excellent effect is exhibited that the position or state of the cam lobe member can be controlled with high responsiveness regardless of the state of the oil.

1 is a schematic view of a variable valve operating apparatus for an internal combustion engine according to a first embodiment of the present invention. FIG. 2 is a schematic perspective view showing one cam unit of the variable valve operating device in FIG. 1 and its periphery. It is a figure showing the motion of the cam lobe member of the variable valve apparatus of FIG. 1, (a) shows the state in which the cam lobe member is in the protruding position, and (b) shows the state in which the cam lobe member is in the retracted position. It is the figure which looked at one cam unit of the variable valve apparatus of FIG. 1 from the head cover side. It is a cross-sectional schematic diagram of one cam unit of the variable valve operating apparatus of FIG. 1, and is a view for explaining the relationship between a fixed element and a cam lobe member. FIG. 2 is a schematic diagram showing one cam unit and a switching device of the variable valve operating apparatus in FIG. 1. It is the schematic diagram showing the relationship between the drive element of the switching apparatus in the variable valve apparatus of FIG. 1, and the fixing element of a fixing device. It is a control flowchart of the electric actuator in the variable valve apparatus of FIG. It is the schematic of the variable valve operating apparatus of the internal combustion engine which concerns on 2nd Embodiment of this invention. FIG. 10 is a schematic perspective view showing one cam unit of the variable valve operating apparatus in FIG. 9 and its periphery. FIG. 10 is a schematic diagram showing one cam unit and a switching device of the variable valve operating apparatus in FIG. 9. FIG. 10 is a schematic diagram showing the movement of the drive element of the switching device in the variable valve apparatus of FIG. 9. It is a figure showing the cam lobe member in one modification of the present invention.

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

  FIG. 1 is a schematic view of a variable valve operating apparatus 1 for an internal combustion engine according to the first embodiment. The variable valve gear 1 is applied to an internal combustion engine 3 mounted on a vehicle. Although this internal combustion engine 3 is a four-cylinder engine, the present invention does not ask | require the number of cylinders of an internal combustion engine applied, a cylinder arrangement | sequence, a combustion type, etc. Further, the internal combustion engine to which the present invention is applied may be used other than the vehicle.

  The variable valve operating apparatus 1 includes a cam unit CU provided on the camshaft S and a switching device (described later) disposed outside the cam unit CU. First, the cam unit CU will be described.

  The variable valve gear 1 according to the first embodiment is applied to an intake valve IV that is an engine valve. However, the variable valve operating apparatus 1 may be applied to the exhaust valve EV that is an engine valve. The internal combustion engine 1 includes two intake valves IV per cylinder.

  FIG. 1 is a schematic cross-sectional view of the upper portion of the internal combustion engine 3 in a direction orthogonal to the axial direction of the camshaft S of the intake valve IV. The camshaft S is disposed between the cylinder head 5, the head cover 7, and the head intermediate member 9 provided therebetween.

  The variable valve gear 1 includes a camshaft S. The camshaft S is provided with a cam unit CU. The camshaft S is rotated by power from the internal combustion engine. More specifically, the camshaft S is rotationally driven by a driving force from the crankshaft. As the cam unit CU rotates in conjunction with the rotation of the camshaft S, the intake valve IV can be lifted via the rocker arm R.

  The cam unit CU includes a cam base member 10 and two cam lobe members 12. The cam base member 10 has one base body portion 10a and two base end portions 10b disposed at both ends of the base body portion 10s. One base body 10a may be divided into two members. In this case, the two members may be connected to each other so as to be integrated in the axial direction. One cam lobe member 12 is disposed between the base main body 10a and the base end 10b. That is, in the cam unit CU, since two cam lobe members 12 are used, the number of the base end portions 10b is two. Therefore, when the cam unit CU has only one cam lobe member 12, the number of base end portions 10b in the cam unit CU is one.

  The base body portion 10a and the base end portion 10b are arranged in the axial direction of the camshaft S and are connected to each other by the inner shaft portion 10c. The inner shaft portion 10c is provided along the axis of the camshaft S. The cam base member 10 has a larger diameter than the inner shaft portion 10a. The base body portion 10a and the base end portion 10b are each substantially cylindrical, and when viewed from the axial direction of the camshaft S (hereinafter simply referred to as the “axial direction”), a substantially circular base circle portion BC (reference base) A shape portion corresponding to a circle). The base circle portion BC corresponds to the outer peripheral surface of the cam base member 10. However, here, the axial length of the base end portion 10b is shorter than the axial length of the base main body portion 10a. In the present specification, a direction perpendicular to the axial direction around the axis of the camshaft S or a direction parallel thereto is referred to as a “radial direction”. Furthermore, a direction around the axis of the camshaft S or a similar direction is referred to as a “circumferential direction”.

  The cam lobe member 12 is disposed between the base body portion 10a and the base end portion 10b adjacent in the axial direction so as to be sandwiched therebetween. The cam lobe member 12 is configured to push the corresponding rocker arm R to lift (that is, move to open) the corresponding intake valve IV as an engine valve. Specifically, the cam lobe member 12 is shaped to have a substantially U shape in a cross section perpendicular to the axis of the camshaft S (see FIG. 3), and has a flat plate shape. The cam lobe member 12 has two opposing surfaces (hereinafter referred to as end surfaces) arranged so as to face in the axial direction, and a surface (hereinafter referred to as a peripheral side surface) extending between these end surfaces. The peripheral side surface has an outer peripheral surface arranged facing the outer side in the radial direction and an inner peripheral surface arranged facing the inner side in the radial direction (that is, the axis line side of the camshaft S). The cam lobe member 12 has a cam portion (main cam portion) 12a having a cam profile on the outer peripheral surface and two end portions on both sides thereof in the circumferential direction. The outer peripheral surface 12o of the cam portion 12a has a cam profile corresponding to a predetermined lift curve. However, the maximum lift amount of the predetermined lift curve of the intake valve IV in the cam lobe member 12 is larger than the maximum lift amount (here, zero) of the intake valve by the base circle portion BC of the cam base member 10. Here, of the two ends of the cam lobe member 12, the end 12b positioned forward (that is, on the advance side) in the rotation direction of the camshaft S is referred to as a front end, and the rotation direction of the camshaft S The end 12c located rearward (that is, on the retard side) is referred to as a rear end.

  The cam lobe member 12 is connected to the cam base member 10 by a support shaft 16. The support shaft 16 is provided so as to pass through the through hole of the front end portion 12b of the cam lobe member 12, and is fixed to the base main body portion 10a and the base end portion 10b. The support shaft 16 is arranged so that its axis is parallel to the axis of the camshaft S. The cam lobe member 12 is provided so as to be movable with respect to the cam base member 10. In other words, the cam lobe member 12 is movable with respect to the cam base member 10, and in particular, can move in a substantially radial direction around the support shaft 16. The support shaft 16 extends from the base end portion 10b of the cam base member 10 so as to protrude outward in the axial direction.

  Further, a stopper pin 18 protruding in the axial direction is fixed to the cam lobe member 12. The stopper pin 18 is a rod-shaped member. Here, the stopper pin 18 protrudes from the vicinity of the front end 12b of the cam lobe member 12 toward the adjacent base end 10b. The stopper pin 18 is also provided in parallel to the axis of the camshaft S, like the support shaft 16. The stopper pin 18 is inserted into a guide hole (long hole) 10d of the adjacent base end 10b and protrudes in the axial direction. The guide hole 10d is designed so as to define a range (movable range) in which the cam lobe member 12 is allowed to move with respect to the cam base member 10, and the stopper pin 18 extends from one end along the longitudinal direction of the guide hole 10d. Can move between the ends. Since the movement of the cam lobe member 12 is restricted within the movable range of the stopper pin 18 in the guide hole 10d, the guide hole 10d and the stopper pin 18 are restrictions for restricting the movable range of the cam lobe member 12 relative to the cam base member 10. Configure the mechanism. Therefore, the cam lobe member 12 can swing around the support shaft 16 with respect to the cam base portion 10 within the movable range of the stopper pin 18 in the guide hole 10d.

  A first spring (elastic member) 19 is disposed on the end surface on the axially outer side of the base end portion 10b. The first spring 19 is disposed so as to urge the stopper pin 18 in a direction for projecting the cam portion 12a of the cam lobe member 12 from the outer peripheral surface of the cam base member 10 radially outward. The first spring 19 is provided with respect to the support shaft 16 provided so as to protrude from the cam base member 10 in the axial direction, and one end of the first spring 19 is provided so as to protrude from the cam base member 10 in the axial direction. The shaft portion 19b is pushed, and the other end biases the stopper pin 18. Therefore, the cam spring member 12 is urged by the first spring 19 toward the protruding position (first position) where the cam portion 12a protrudes from the cam base member 10 in the radial direction. Therefore, when the urging force is applied only to the cam lobe member 12 from the first spring 19, the cam lobe member 12 is in the protruding position.

  The movable range of the stopper pin 18 in the guide hole 10d is set so that the cam lobe member 12 can move between the protruding position and the retracted position (second position). The storage position is a non-projecting position where the cam portion 12a of the cam lobe member 12 does not project from the cam base member 10 in the radial direction.

  When the cam lobe member 12 is not in contact with the rocker arm R, for example, in the state shown in FIG. 3A, the cam lobe member 12 is in the protruding position by the urging force of the spring 19. As the camshaft S rotates, the cam unit CU rotates, the cam lobe member 12 rotates, and when the cam portion 12a of the cam lobe member 12 starts to contact the rocker arm R, the cam portion 12a is pressed by the rocker arm R. Receive. When the cam portion 12a of the cam lobe member 12 starts to contact the rocker arm R and further rotates, the cam lobe member 12 is moved from the protruding position where the cam portion 12a protrudes radially outward of the cam base member 10, and the cam portion 12a is 10 to the retracted position retracted radially inward from the outer peripheral surface. Then, by further rotating, the cam portion 12a comes out of contact with the rocker arm R, and the cam lobe member 12 returns to the protruding position. FIG. 3B shows the cam lobe member 12 in the retracted position.

  The two cam lobe members 12 in one cam unit CU are configured to exhibit the same behavior. However, in FIG. 2, for reference, the cam lobe member 12 on the left side of the paper is drawn in a protruding position, and the cam lobe member 12 on the right side of the paper is drawn in a retracted position. However, in the present embodiment, the cam lobe member 12 is actually located in the retracted position only when the cam lobe member 12 is in sliding contact with the rocker arm R as described with reference to FIG. Please keep in mind. That is, the cam lobe member 12 is actually located at the retracted position when the cam portion 12a of the cam lobe member 12 is opposed to the rocker arm R when it can swing with respect to the cam base member 10.

  The swinging motion between the protruding position and the retracted position of the cam lobe member 12 is repeated with the rotation of the camshaft S unless the cam lobe member 12 is fixed to the cam base member 10 by the fixing device 24 described below. .

  Further, a fixing device 24 for selectively fixing the cam lobe member 12 to the cam base member 10 is provided. With the fixing device 24, the cam lobe member 12 is in a state where the cam lobe member 12 is fixed to the cam base member 10 (fixed state) and a state where the cam lobe member 12 is not fixed to the cam base member 10 (non-fixed). State or free state). The movement of the cam lobe member 12 when the cam lobe member 12 is in the non-fixed state is as already described with reference to FIG. And the fixing device 24 is comprised so that the cam lobe member 12 can be fixed to the said protrusion position.

  The fixing device 24 includes a fixing element 26, a ball member 28, and a second spring 30. As is apparent from FIGS. 1 and 5, the fixing element 26 includes a main body portion 26a, a protruding portion 26b protruding from the main body portion 26a in a substantially radial direction, and an engaging uneven portion 26d provided on the main body portion 26a. . The main body portion 26a has a substantially cylindrical shape and is configured to be completely accommodated in the lateral hole 10e of the base main body portion 10a. The protruding portion 26b is rod-shaped, is fixed to the main body portion 26a, and is arranged so that the tip protrudes through a guide hole 10f that opens on the outer peripheral surface of the base main body portion 10a. The engaging uneven portion 26d is disposed on the substantially opposite side of the protruding portion 26b of the main body portion 26a. The ball member 28 and the second spring 30 are disposed in a hole 10g extending in a direction perpendicular to the axis of the horizontal hole 10e (that is, the axis of the camshaft S) provided on the back side of the horizontal hole 10e of the base body 10a. . The second spring 30 is disposed so as to urge the ball member 28 toward the side hole 10e, and presses the ball member 28 against the engaging uneven portion 26d. The ball member 28 is configured as an engaging member that engages with the engaging uneven portion 26d. In FIG. 5 and FIG. 6, the ball member 28 is engaged with the concave portion of the engaging uneven portion 26d of the fixing element 26 in the release position described later.

  The protrusion part 26b is comprised so that it may act by the switching apparatus 40 mentioned later. In FIG. 5, the protruding portions 26 b are arranged at positions away from the corresponding cam lobe members 12. When the cam lobe member 12 is in the projecting position, if the projecting portion 26b is forcibly moved from the solid line state in FIG. 5 to the cam lobe member 12 side, the main body portion 26a is moved to the cam lobe member 12 side, and the base main body portion 10a The lateral hole 10e is partially removed and engaged with the engagement hole 12d of the cam lobe member 12 (see the broken line in FIG. 5). At this time, the ball member 28 may be engaged with the concave portion of the engaging uneven portion 26 d of the fixing element 26. Thereby, the cam lobe member 12 is fixed at the protruding position. Thus, when the protrusion part 26b is moved, the force which acts on the main-body part 26a via the protrusion part 26b from the switching apparatus 40 exceeds the holding force of the fixing element 26 by the urging | biasing force of the 2nd spring 30. FIG. Therefore, the ball member 28 is moved so as to compress the second spring 30, and thus the main body portion 26a can move in the lateral hole 10e. When the cam lobe member 12 is in the protruding position, the engagement hole 12d of the cam lobe member 12 is axially aligned with the lateral hole 10e of the base body 10a, and when the cam lobe member 12 is in the retracted position, the engagement of the cam lobe member 12 is The joint hole 12d deviates from the lateral hole 10e of the base body 10a.

  Similarly, when releasing the main body portion 26a of the fixing element 26 from the engaged state with the cam lobe member 12, the switching device 40 acts on the protruding portion 26b so as to move the main body portion 26a to the back side of the lateral hole 10e, As a result, the main body 26a can be in the state shown by the solid line in FIG. Here, the fact that the fixing element 26 is not engaged with the cam lobe member 12 and is in the position shown by the solid line in FIG. 5 is said to be in the release position. The locking element 26 in the release position releases the cam lobe member 12 so that the cam lobe member 12 can move relative to the cam base member 10, so that the cam lobe member 12 has a protruding position and a retracted position as described above. It can swing between. Further, here, the fact that the fixing element 26 is in the position indicated by the broken line in FIG. 5 engaged with the cam lobe member 12 is said to be in the engaging position. Since the fixing element 26 in the engaging position engages with the cam lobe member 12 so as to fix the cam lobe member 12 to the cam base member 10, the cam lobe member 12 is rockered by the cam portion 12a as the cam shaft S rotates. The arm R can be pushed down to open the intake valve IV.

  The switching device 40 is a device for switching the position of the fixing element 26 between the engagement position and the release position. As shown in FIGS. 1 and 4, the switching device 40 includes a drive element 42 disposed on the radially outer side of the cam base member 10 and an electric actuator 44 with a link mechanism for moving the drive element 42. The drive element 42 is thinner toward its tip and has a substantially ax shape. The driving element 42 is configured to act on the protruding portion 26b of the fixing element 26, and may be referred to as an arm member. The electric actuator 44 is configured to be operable by control by an ECU, which will be described later. The electric actuator 44 is in an engagement side position in which the fixing element 26 is set to the engaging position or maintained in the engaging position, and the fixing element 26 is set in the releasing position. The drive element 42 is configured to selectively move between a release position that maintains the release position.

  The schematic diagram of FIG. 6 is drawn to show the positional relationship between the fixed element 26 of the cam unit and each element of the switching device 40. 6A is a cross-sectional view of the cam unit CU and corresponds to FIG. 5, and FIG. 6B shows the position of the protruding portion 26b on the outer peripheral surface of the cam base member 10 of the cam unit CU. ) Shows a portion related to one cylinder in the switching device 40. As shown in FIG. 6, the direction of the drive element 42 can be changed by the operation of the electric actuator 44. As shown in FIG. 1, the drive element 42 is attached to the head intermediate member 9 with a pin member 42a, and the drive element 42 is configured to be rotatable around the pin member 42a within a predetermined range. This is because the movable member 42b of the link mechanism is provided between the actuator 44 and the actuator 44. In FIG. 6, the movement of the driving element 42 due to the operation of the electric actuator 44 is schematically represented by a solid line and a broken line.

  Here, based on FIGS. 6 and 7, the movement of the fixed element 26 due to the change in the position of the drive element 42 will be described. FIG. 7 is a diagram schematically showing the positional relationship between the drive element and the protrusion at the same time. In each of (a) to (k), the view from the outside of the cam base member and the axial direction of the cam shaft. The figure in the cross section orthogonal to is shown side by side.

  The position of the drive element 42 (see FIG. 7A) indicated by a broken line in FIG. 6 is related to the release position of the fixing element 26. At this time, the cam lobe member 12 is not fixed with respect to the cam base member 10 and can swing as described above.

  When the cam lobe member 12 is fixed to the cam base member 10, the electric actuator 44 is actuated to move the drive element 42 to the position shown by the solid line in FIG. The state of the driving element 42 at this time is shown in FIG. 7B. When the driving element 42 is moved in this way, the driving element 42 is basically in a state of being separated from the protruding portion 26b by a predetermined distance or more. In the state shown in FIG. 7B, the position of the drive element 42 is fixed, and the camshaft S further rotates in this state. As the camshaft S rotates, the protruding portion 26b protruding radially outward from the outer peripheral surface of the cam base member 10 comes closer to and comes into contact with the drive element 42 (see FIG. 7C). As the camshaft S further rotates, the protrusion 26b receives a force from the drive element 42 toward the engagement position along the substantially ax-shaped tip end contour of the drive element 42. As a result, the fixing element 26 changes from the state of FIG. 7C to the states of FIG. 7D and FIG. 7E, and is positioned at the engagement position. As the camshaft S further rotates, the protruding portion 26b moves away from the drive element 42 (see FIG. 7 (f)). Once the fixing element 26 is positioned in the engaging position in this way, the fixing element 26 is not moved even if the protrusion 26b approaches the drive element 42 again (if it comes into contact) as the camshaft S further rotates. It remains in the engaged position (see FIGS. 7 (g) to 7 (k)).

  The electronic control unit (ECU) 50 is substantially constituted by a computer including an arithmetic processing device (for example, CPU), a storage device (for example, ROM, RAM), an A / D converter, an input interface, an output interface, and the like. Various sensors are electrically connected to the input interface. Based on signals from these various sensors, the ECU electrically outputs an operation signal or a drive signal from the output interface so that the internal combustion engine can be smoothly operated or operated in accordance with a preset program or the like. Thus, the ECU 50 controls the operation of the electric actuator 44 in addition to the operation of a fuel injection valve (not shown). Here, some of the sensors will be specifically described. An engine speed sensor 52 for detecting the engine speed is provided. An engine load sensor 54 for detecting the engine load is also provided. As the engine load sensor 54, a throttle opening sensor, an accelerator opening sensor, an air flow meter, an intake pressure sensor, or the like can be used.

  Control of the electric actuator 44 by the ECU 50 will be described based on the flowchart of FIG.

  First, in step S801, it is determined whether or not the vehicle is in a predetermined operating state. Here, the ECU 50 searches for preset data or performs a predetermined calculation based on the engine rotational speed detected by the engine rotational speed sensor 52 and the engine load detected by the engine load sensor 54. Thus, it is determined whether or not the current operation state is a predetermined operation state. The internal combustion engine in the present embodiment is a four-cylinder engine, and can perform a reduced-cylinder operation in which two cylinders are deactivated in a predetermined operation state where the engine load is low. In this internal combustion engine, the variable valve operating device is applied to a reduced cylinder operation cylinder. Therefore, the predetermined operation state is set as an operation state in which the reduced cylinder operation is performed. However, the present invention allows the predetermined operating state to be another operating state. As described above, the number of cylinders of the internal combustion engine to which the present invention is applied is not limited to this embodiment, and the reduced-cylinder operation in which two cylinders in the four-cylinder engine are deactivated is only an example.

  If an affirmative determination is made in step S801 because it is a predetermined operation state, the release flag is turned on so that the drive element 42 is positioned in the release side position so that the fixed element 26 is in the release position in step S803. Thereby, the ECU 50 controls the electric actuator 44 so that the drive element 42 is positioned at the release side position when the drive element 42 is not yet at the release side position.

  On the other hand, if a negative determination is made in step S801 because it is not a predetermined operation state, the release flag is turned OFF in step 805. Thus, the ECU 50 controls the electric actuator 44 so that the drive element 42 is positioned at the engagement side position when the drive element 42 is not yet at the engagement side position.

  As described above, in the variable valve operating apparatus 1, by controlling the operation of the electric actuator 44, the fixing element 26 is selectively moved to fix the cam lobe member 12 to the cam base member 10 or release it from the cam base member 10. I can do it. Since the control responsiveness of the electric actuator is superior to the hydraulic responsiveness, according to the above embodiment, the position or state of the cam lobe member can be controlled with higher responsiveness.

  Moreover, in the said variable valve apparatus 1, the separate switching apparatus 40 is provided with respect to each cylinder. The operation of the switching device 40, that is, the switching of the position of the drive element 42 is performed when the drive element 42 is in a state where it does not interfere with the protruding portion 26b. The state in which the drive element 42 does not interfere with the protrusion 26b occurs in a range of about 300 ° in the rotation angle of the camshaft S. Therefore, according to the variable valve operating apparatus 1, the switching section of the drive element 42 can be relatively long. This brings about an advantage that the section or period in which the cam lobe member 12 can be fixed to the cam base member 10 can be relatively long because the cam lobe member 12 is constantly biased to the protruding position by the spring.

  Next, a second embodiment of the present invention will be described. The variable valve operating apparatus 101 according to the second embodiment is applied to the in-line four-cylinder internal combustion engine 3, and is similar to the variable valve operating apparatus 1 of the first embodiment with respect to the camshaft S of the intake valve IV. Has been applied. In the variable valve gear 1 of the first embodiment, the switching device 40 is provided for each cylinder. However, in the variable valve operating apparatus 101 of the second embodiment, a switching apparatus including a single or common electric actuator 44 for the intake valves IV of two cylinders corresponding to the reduced cylinder operation among the four cylinders. 140 is applied. Hereinafter, the same or similar components as those already described with respect to the variable valve operating apparatus 1 of the first embodiment are denoted by the same reference numerals, and redundant description is omitted. Below, the characteristic structure of the variable valve apparatus 101 is demonstrated. In addition, the variable valve operating apparatus 101 of 2nd Embodiment similarly has the effect (the responsiveness improvement in control of a cam lobe member) demonstrated about the variable valve operating apparatus 1 of 1st Embodiment.

  9 to 11 schematically show the variable valve apparatus 101 of the second embodiment. However, FIGS. 9 to 11 correspond to FIGS. 1, 2, and 6 in the first embodiment, respectively. In particular, the schematic diagram of FIG. 11 is drawn to show the positional relationship between the fixed element 26 of the cam unit and each element of the switching device 140. 11A is a schematic cross-sectional view of the cam unit CU, FIG. 11B is a developed view of the outer peripheral surface of the cam base member 10 of the cam unit, and FIG. 11C relates to one cylinder in the switching device. Indicates the part. Although the variable valve apparatus 101 includes the ECU 50 and the sensors 52 and 54 in the same manner as the variable valve apparatus 1, they are omitted in the drawing.

  In the variable valve operating apparatus 101, the position of the driving element 42 can be switched by the operation of the electric actuator 44 based on the output of the ECU 50, but the switching is substantially performed at an appropriate timing according to each cylinder. The guide mechanism 142 of the element 42 is further provided. The guide mechanism 142 includes the cam base member 10, in particular, a guide groove 144 provided on the outer peripheral surface of the base main body 10 a, and a guide member 146 provided at the tip of the drive element 42. The guide member 146 is configured as a round tip so as to be slidable in the guide groove 144, but may be various pin members.

  Further, the switching device 140 includes a drive element 42, an electric actuator 44, and a link mechanism 46 between them so as to adapt the movement of the drive element 42 to the movement along the guide groove 144. The link mechanism unit 46 includes a position control device 46b whose position is changed by the movement of the movable member 42b with the rotation of the shaft member 46a rotated within a predetermined angle range by the operation of the electric actuator 44, the position control device 46b, and the drive element. And a third spring 46c serving as a buffer member disposed between the first spring 46c and the third spring 46c. The position control device 46b includes a piston member 46i that can slide in a substantially cylindrical housing 46h. Within the housing 46h, the piston member 46i can reciprocate in the axial direction. The two positions of the piston member 46i selectively positioned in the housing 46h correspond to the engagement position and the release position of the fixing element 26, respectively.

  The guide grooves 144 are continuously formed on the outer peripheral surface of the cam base member 10 so as to define a series of guide routes in the circumferential direction. Then, the guide groove 144 is formed so as to be divided into two forks around the projecting portion 26b of the fixing element 26 so as to sandwich the projecting portion 26b. That is, the guide groove 144 has a portion (hereinafter, a bifurcated portion) 144a that is divided into two passages and a portion (hereinafter, a common portion) 144b that is a single passage.

  The guide member 146 at the tip of the drive element 42 is always located in the guide groove 144. The control of the electric actuator 44 by the ECU 50 causes the shaft member 46a to be in one of a release side position for positioning the fixing element 26 in the release position and an engagement side position for positioning the fixing element 26 in the engagement position. (See FIG. 9). By this rotation, the piston member 46 i of the position control device 46 b is moved to either the release side position corresponding to the release position of the fixing element 26 or the engagement side position corresponding to the engagement position of the fixing element 26. Or kept in that position. Depending on the position of the piston member 46, the drive element 42 is moved along one of the corresponding grooves in the bifurcated portion 144a of the guide groove 144. In the common portion 144b that is one passage other than the bifurcated portion 144a, the drive element 42 cannot move to a position corresponding to the position of the piston member 46i of the position control member 46b. Therefore, the third spring 46c acts so as to position the drive element 42 in one of the passages selected by the bifurcated portion 144a while maintaining the position of the drive element 42 at this time stably.

  Based on FIG. 12, an example of the movement of the drive element 42 accompanying the guide member 146 being guided along the guide groove 144 will be described. FIG. 12 is a diagram schematically showing a portion related to the cam lobe member 12 on the right side of FIG. In FIG. 12, the position of the piston member 46i of the position control device 46b is fixed, and the guide groove 144 of the cam base member 10 extends from the upper side to the lower side of the page as indicated by the white arrow (according to the rotation direction of the camshaft S). FIG. 12 is shown as moving in a flowing manner.

  In FIG. 12A, the protrusion 26b of the fixing element is in the release position, and the piston member 46i of the position control device 46b is positioned in the release side position. In FIG. 12A, since the piston member 46i is positioned at the release side position, a force that tilts to the right side of the sheet as shown by the arrow acts on the drive element 42 from the third spring 46c. However, the drive element 42 is guided and held at the position along the common portion 144b of the guide groove 144, and the attitude of the drive element 42 is stably maintained by the buffering action of the third spring 46c.

  When the camshaft S further rotates from the state shown in FIG. 12A, the drive element 42 reaches the branch portion between the common portion 144b and the bifurcated portion 144a of the guide groove 144. Since the driving element 42 already has a force that tilts to the right side of the drawing from the third spring 46c, the driving element 42 has a route corresponding to the disengagement side position of the bifurcated portion 144a (in FIG. 12B). Guided by the right route (see FIG. 12B). Here, since the fixing element 26 already provided with the protrusion 26b is positioned in the release position, the driving element 42 does not move the fixing element 26.

  Further, FIG. 12C shows a case where the electric actuator 44 is operated and the piston member 46i is moved to the engagement side position in the state shown in FIG. At this time, the drive element 42 is in a route corresponding to the release side position in the bifurcated portion 144a of the guide groove, and is restricted so that the position of the drive element 42 cannot be switched. Therefore, as long as the bifurcated portion 144a exists at this time, the drive element 42 cannot reach the route corresponding to the engagement side position, and acts on the protrusion 26b so as to position the fixing element 26 at the engagement position. I can't. On the other hand, when the drive element 42 is guided by the bifurcated portion 144a, it is a period during which the drive element 42 can interfere with the protrusion 26b, and it is not preferable to forcibly switch the position of the drive element 42 at this time. . However, as described above, the position of the drive element 42 cannot be switched by the guide groove, and the drive element 42 is maintained in an appropriate posture by the buffering action of the third spring 46c. Unexpected interference can be reliably suppressed.

  As described above, in the variable valve operating apparatus 1 of the first embodiment, the electric actuator 44 cannot be operated during the period in which the drive element 42 can interfere with the protruding portion 26b. The electric actuator 44 can be operated during such a period by a guide action or the like by the guide groove 144. Therefore, according to the variable valve operating apparatus 101 of the second embodiment, even if the common electric actuator 44 is operated for all the intake valves of a plurality of cylinders, the drive elements 42 are appropriately controlled at appropriate timing for each cylinder. Can be positioned at any position. Therefore, the number of the electric actuators 44 of the switching device 140 can be reduced, and the state of the cam lobe member 12 can be switched between the fixed state and the non-fixed state with a single simple control. However, in the second embodiment, the driving of the piston member by the operation of the electric actuator 44 may be performed at a timing other than the timing at which the driving element 42 reaches the branch portion between the common portion 144b and the bifurcated portion 144a of the guide groove 144. . This is to move the drive element 42 along the guide groove 144 more reliably.

  As mentioned above, although this invention was concretely demonstrated based on two embodiment, this invention is not restrict | limited to these embodiment. For example, the cam lobe member 12 is basically biased to the protruding position and moved to the retracted position by coming into contact with the rocker arm R, but may have other forms. A cam lobe member 112 shown in FIG. 13 includes a main cam portion 112a corresponding to the cam portion 12a of the cam lobe member 12 and a pressing portion 112b, and has a substantially ring shape. The cam lobe member 112 is basically disposed by the spring 19 so that the pushing portion 112b protrudes radially outward from the outer peripheral surface of the cam base member 110 (see FIG. 13B). The main cam portion 112a is configured to protrude radially outward when it comes into contact with the arm and is pressed by the arm (see FIG. 13A). Each fixing device and switching device of the above-described embodiment may be applied to such a cam lobe member 112.

  Further, like the cam base member 110 shown in FIG. 13, the cam base member 110 may have an outer peripheral surface shape corresponding to a predetermined lift curve, instead of having a base circular outer peripheral surface. Note that the maximum cam lift amount of the predetermined lift curve in the cam base member 110 is preferably smaller than the maximum cam lift amount in the cam lobe member 112. In such a case, for example, the variable valve operating apparatus 101 of the second embodiment can be provided in common for the intake valves of all the cylinders. In this case, the variable valve operating apparatus 101 can move the intake valve by two different lift amounts.

  In the variable valve operating apparatus, the cam lobe member receives a pressing force from a rocker arm that is a follower member connected to an intake valve that is an engine valve. However, the cam lobe member may be configured to receive a pressing force directly from the engine valve.

  The embodiment of the present invention is not limited to the above-described embodiment, and includes all modifications, applications, and equivalents included in the concept of the present invention defined by the claims. Therefore, the present invention should not be construed as being limited, and can be applied to any other technique belonging to the scope of the idea of the present invention.

DESCRIPTION OF SYMBOLS 10 Cam base member 12 Cam lobe member 16 Support shaft 19 1st spring 24 Fixing device 26 Fixing element 26a Main body part 26b Protrusion part 40,140 Switching device 42 Drive element 44 Electric actuator

Claims (1)

A variable valve operating apparatus for an internal combustion engine that makes the lift amount of an engine valve variable,
A cam base member provided on the cam shaft and rotating according to the rotation of the cam shaft;
A cam lobe member having a main cam portion between the first position where the main cam portion projects radially from the cam base member and the second position where the main cam portion does not project from the cam base member. A cam lobe member movable with respect to,
A biasing member that biases the cam lobe member against the cam base member, the biasing member biasing the cam lobe member toward one of the first position and the second position. An urging member provided;
A fixing element for fixing the cam lobe member in the first position to the cam base member, the fixing element engaging the cam lobe member so as to fix the cam lobe member to the cam base member. The locking element is movable in the axial direction of the camshaft between a mating engagement position and a release position for releasing the cam lobe member so that the cam lobe member can move relative to the cam base member; A fixing element having a portion and a projecting portion projecting radially from the main body portion;
A switching device for switching the position of the fixed element between the engagement position and the release position, the switching device including a drive element disposed radially outward of the cam base member, and the drive element An electric actuator for moving
A variable valve operating device for an internal combustion engine.