JP2015169182A - Variable valve device of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a variable valve device of an internal combustion engine which can increase the rigidity of a changeover pin by simplifying a structure of a cam changeover mechanism while keeping a pitch of the changeover pin in an axial line direction of a cam shaft constant.SOLUTION: In a variable valve device 2, a first changeover pin 51 has a first protrusion 51D which protrudes from a first accommodation part 72 so as to be insertable into a guide groove 43, and can freely contact with a first changeover cam 43A, a second changeover pin 52 has a second protrusion 52D which protrudes from a second accommodation part 73 so as to be insertable into the guide groove 43, and can freely contact with a second changeover cam 43B, and center axes L1, L2 of the first protrusion 51D and the second protrusion 52D in a radial direction of a cam shaft 3 are set between center axes L3, L4 in the radial direction of the cam shaft 3 of the first accommodation part 72 and the second accommodation part 73.

Description

  The present invention relates to a variable valve operating apparatus for an internal combustion engine that moves a cam carrier having a plurality of cams having different valve operating characteristics in the axial direction of a cam shaft.

  2. Description of the Related Art Conventionally, as a variable valve operating apparatus for an internal combustion engine, a variable valve operating apparatus that switches a cam that operates a valve by moving a cam carrier having a plurality of cams with different valve operating characteristics on the outer periphery in the axial direction of the cam shaft is known. (For example, refer to Patent Document 1).

  In this variable valve operating apparatus, a switching pin provided on an operating member so as to be able to reciprocate in the radial direction of the cam carrier is inserted into and removed from a helical guide groove formed on the outer periphery of the cam carrier, whereby the cam carrier is moved along the axis. Move in the direction.

Japanese Patent No. 4330618

  However, in the above-described conventional variable valve operating apparatus, since the two switching pins are installed at a large distance in the axial direction of the cam shaft, the cam carrier corresponds to the two switching pins in order to reciprocate the cam carrier. Therefore, there is a problem that the structure of the cam switching mechanism is complicated.

  In order to increase the rigidity of each switching pin, it is conceivable to increase the width of each switching pin in the axial direction of the cam shaft. In this case, the pitch of the switching pin that switches the cam position is considered. Since the (distance between the switching pins) is changed, the cam position must be changed accordingly.

  The present invention has been made by paying attention to the above-described problems, and while simplifying the structure of the cam switching mechanism and maintaining the pitch of the switching pin in the axial direction of the cam shaft, the rigidity of the switching pin is improved. It is an object of the present invention to provide a variable valve operating apparatus for an internal combustion engine that can increase the engine speed.

  According to a first aspect of the present invention, a camshaft rotatably supported by a cylinder head is provided so as to be coaxial with the camshaft, rotates integrally with the camshaft, and is axial with respect to the camshaft. The cam carrier is disposed so that the first cam and the second cam are adjacent to each other, and the cam carrier is arranged in the axial direction of the cam shaft. A cam switching portion for switching between a first cam and a second cam that move and actuate the valve, and the cam carrier has a first position for actuating the valve by the first cam and a valve by the second cam. The concave shape portion is formed on the outer peripheral surface of the cam carrier so as to circulate the cam carrier, and in the concave shape portion, one of the pair of side walls facing each other is formed. Cam carrier A first switching cam that moves the cam carrier to the first position, and the other of the pair of side walls includes a second switching cam that moves the cam carrier to the second position. In the valve device, the cam switching portion is provided in each of the first accommodation portion and the second accommodation portion, and the first accommodation portion and the second accommodation portion that are adjacent along the axial direction of the cam shaft, A first switching pin and a second switching pin that are reciprocally movable in the radial direction of the camshaft. The first switching pin protrudes from the first housing portion so as to be freely inserted into the concave portion, A first projecting portion that can contact the first switching cam; a second switching pin that projects from the second housing portion so as to be inserted into the concave shape portion; The central axis of the first protrusion and the second protrusion in the radial direction of the camshaft , And it is configured from those installed between the central axis in the radial direction of the cam shaft of the first housing portion and second housing portion.

  As a second aspect of the present invention, the first switching pin and the second switching pin are coupled by a coupling mechanism that moves in the opposite direction along the radial direction of the cam shaft, and the coupling mechanism is A first rack formed on a side surface of the switching pin; a second rack formed on a second switching pin facing the first rack; and a gear meshing with the first rack and the second rack. It may be comprised including.

  As a third aspect of the present invention, the first switching pin is provided at the lower portion of the first switching pin so as to come into contact with the bottom surface of the first housing portion and regulate the protruding amount of the first switching pin relative to the first housing portion. A second locking surface that is formed with a locking surface and that contacts the bottom surface of the second housing portion at the bottom of the second switching pin and regulates the amount of protrusion of the second switching pin relative to the second housing portion. May be formed.

  As described above, according to the first aspect described above, the cam switching mechanism that switches between the first cam and the second cam has a single recess having the first switching cam and the second switching cam as side walls. Since the shape portion, the first switching pin that can contact the first switching cam, and the second switching pin that can contact the second switching cam are configured, each of the first switching pin and the second switching pin It is not necessary to form the concave portions individually. For this reason, a cam switching mechanism can be made into a simple structure.

  Further, the first switching pin protrudes from the first housing portion so as to be inserted into the concave shape portion, has a first protruding portion that can contact the first switching cam, and the second switching pin has the first switching pin. A second projecting portion that can be inserted into the concave shape portion from the two accommodating portions and that can contact the second switching cam, and the first projecting portion and the second projecting portion in the radial direction of the camshaft. A central axis is installed between the central axes in the radial direction of the cam shafts of the first accommodating part and the second accommodating part.

  For this reason, the pitch of the first switching pin and the second switching pin in the axial direction of the cam shaft, which can be switched between the first cam and the second cam by moving the cam carrier in the axial direction of the cam shaft. It is possible to increase the strength and rigidity of the first switching pin and the second switching pin while keeping the constant.

  According to said 2nd aspect, the connection mechanism which moves a 1st switching pin and a 2nd switching pin to a mutually reverse direction, the 1st rack formed in the side surface of the 1st switching pin, A second rack formed on a second switching pin facing one rack, and a gear meshing with the first rack and the second rack are configured.

  For this reason, the connection mechanism which consists of a rack and a gear which requires a big installation space can be easily provided in the 1st switching pin and 2nd switching pin which can aim at enlargement by increasing intensity | strength and rigidity. .

  In addition, the first switching pin and the second switching pin are provided with the first projecting portion and the second projecting portion, so that the cam can be enlarged even if the first switching pin and the second switching pin are enlarged. The pitch of the first switching pin and the second switching pin in the axial direction of the shaft can be kept constant.

  According to said 3rd aspect, the 1st which regulates the protrusion amount of the 1st switching pin with respect to a 1st accommodating part in contact with the bottom face of a 1st accommodating part at the lower part of a 1st switching pin A second locking surface that is formed with a locking surface and that contacts the bottom surface of the second housing portion at the bottom of the second switching pin and regulates the amount of protrusion of the second switching pin relative to the second housing portion. Therefore, when the first locking surface of the first switching pin comes into contact with the bottom surface of the first housing portion, the second switching pin is opposite to the first switching pin via the coupling mechanism. The amount of movement when moving to can be regulated.

  For this reason, it does not move until the second switching pin is caught in the oil discharge hole, and it is possible to more effectively prevent the second switching pin from being caught on the edge of the oil discharge hole.

FIG. 1 is a 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 an exploded perspective view of the variable valve operating apparatus for the internal combustion engine according to the embodiment of the present invention. FIG. 3 is a perspective view showing a cam carrier in the variable valve operating apparatus for an internal combustion engine according to the embodiment of the present invention. FIG. 4 is a cross-sectional view showing a state in which the first accommodating portion into which the first switching pin is inserted in the variable valve operating apparatus for an internal combustion engine according to the embodiment of the present invention is cut in the axial direction. FIG. 5 is a cross-sectional view taken along arrow VV in FIG. FIG. 6 is a cross-sectional view showing a state in which the second accommodating portion into which the second switching pin is inserted in the variable valve operating apparatus for an internal combustion engine according to the embodiment of the present invention is cut in the axial direction. 7 is a cross-sectional view taken along arrow VII-VII in FIG. FIG. 8 is an exploded perspective view of the coupling mechanism in the variable valve operating apparatus for the internal combustion engine according to the embodiment of the present invention. FIG. 9 is a perspective view showing a state where the cam carrier in the variable valve operating apparatus for the internal combustion engine according to the embodiment of the present invention is installed at the first position (position where the high-speed cam is selected). FIG. 10 is a perspective view showing a state during a switching operation between the first switching pin and the second switching pin in the variable valve operating apparatus for the internal combustion engine according to the embodiment of the present invention. FIG. 11 is a perspective view showing a state in which the cam carrier in the variable valve operating apparatus for an internal combustion engine according to the embodiment of the present invention starts moving toward the second position (position where the low speed cam is selected). FIG. 12 is a perspective view showing a state where the cam carrier in the variable valve operating apparatus for an internal combustion engine according to the embodiment of the present invention is installed at the second position (position where the low-speed cam is selected). FIG. 13 is a perspective view of the cam carrier when the second cam in the variable valve operating apparatus for an internal combustion engine according to another embodiment of the present invention is a pause cam.

Embodiments of a variable valve operating apparatus for an internal combustion engine according to the present invention will be described below with reference to the drawings.
FIGS. 1-13 is a figure which shows the variable valve operating apparatus of the internal combustion engine of one Embodiment which concerns on this invention.

First, the configuration will be described.
(Schematic configuration of variable valve operating device)
As shown in FIG. 1, a variable valve gear 2 for an internal combustion engine is built in a head 1 </ b> A provided opposite to the cylinder head 1 and the cylinder head 1.

As shown in FIG. 2, the variable valve apparatus 2 includes a cam shaft 3, a cam carrier 4, and a cam switching unit 5 installed above the cam carrier 4, and the lift state of the intake valve 13 is changed. Switch cams to change. As shown in FIG. 1, the cylinder head 1 includes a camshaft 30 on the exhaust valve side, an exhaust cam 40, and the like.
(Rocker arm)

  1 and 2, the variable valve apparatus 2 of the present embodiment uses a rocker arm 11 of a type that swings as the cam carrier 4 rotates. The rocker arm 11 is installed such that a recess formed on the lower surface of the one end portion 11C abuts on a pivot 12A of a hydraulic lash adjuster (HLA) 12. 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 abuts on either the high speed cam 41 constituting the first cam of the cam carrier 4 or the low speed cam 42 constituting the second cam.

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. The intake valve 13 is provided so as to be able to advance and retreat in the axial direction with respect to the cylinder head 1 and closes the intake port 15 and the combustion chamber 16 that are opened and closed by the valve spring 14, that is, the intake port 13. Is biased in the direction.
(Camshaft)

  In FIG. 1, the cam shaft 3 is rotatably supported by a lower cam housing 6 and an upper cam housing 7 which are bearings installed on the upper part of the cylinder head 1. The camshaft 3 is provided with an interlocking portion so as to rotate in conjunction with a crankshaft (not shown) by a chain or belt (not shown).

  The lower cam housing 6 and the upper cam housing 7 are covered with the head cover 1 </ b> A and are built in the cylinder head 1. The rotational speed of the camshaft 3 is set to be 1/2 of the rotational speed of the crankshaft.

In the variable valve operating apparatus 2 of the present embodiment, the cam shaft 3 is installed so as to extend along the front-rear direction of the engine having the cylinder head 1 that constitutes a part of the internal combustion engine (the left-right direction on the plane of FIG. 2). Has been.
As shown in FIG. 2, spline external teeth 31 having a predetermined width dimension in the axial direction are formed around the outer peripheral surface of the predetermined region in the length direction of the cam shaft 3.

  As shown in FIGS. 2, 5, and 6, a positioning mechanism 32 is provided in a region adjacent to the axial direction of the region where the spline external teeth 31 are formed on the camshaft 3. The storage recess 33 formed to be recessed along the radial direction with respect to the cam shaft 3, the spring 34 stored in the storage recess 33, and stored in the storage recess 33 so as to be separated from the surface of the cam shaft 3. And a ball 35 installed so that the portion protrudes.

As shown in FIG. 5, the ball 35 is locked to a first position positioning groove 46 and a second position positioning groove 47 provided on the cam carrier 4 side described later.
(Cam carrier)

  2 and 3, the cam carrier 4 is formed in a cylindrical shape so as to surround the cam shaft 3, and a spline inner tooth 45 that meshes with the spline outer teeth 31 of the cam shaft 3 on the inner peripheral surface of the cam carrier 4. Is formed. For this reason, the cam shaft 3 and the cam carrier 4 rotate together, and the cam carrier 4 is movable in the axial direction with respect to the cam shaft 3.

  Further, a first position positioning groove 46 and a second position positioning groove 47 are formed in a region adjacent to a region where the spline inner teeth 45 are formed on the inner peripheral surface of the cam carrier 4. Yes.

  The first position positioning groove 46 and the second position positioning groove 47 are configured so that the ball 35 of the positioning mechanism 32 provided on the camshaft 3 side is locked, so that the cam carrier 4 can be Positioning is performed between the position and the second position by a click operation.

  The cam carrier 4 is integrally provided with a high-speed cam 41 as a first cam and a low-speed cam 42 as a second cam, which are different in valve operation characteristics, along the axial direction. In addition, the one-piece | unit structure of the high speed cam 41 and the low speed cam 42 is installed in a pair at predetermined intervals.

  When a pair of high-speed cams 41 is selected, each high-speed cam 41 is positioned above the rocker arm 11, and when a pair of low-speed cams 42 is selected, each low-speed cam 42 is above the rocker arm 11. Located in.

  That is, the interval between the high-speed cams 41, the interval between the low-speed cams 42, and the interval between the intake valves 13 are set to be the same. The cam carrier 4 is movable between a first position where the intake valve 13 is operated by the high speed cam 41 and a second position where the intake valve 13 is operated by the low speed cam 42.

  As shown in FIG. 3, the high-speed cam 41 includes a base circle portion 41 </ b> A that serves as a foundation, and a nose portion 41 </ b> B that protrudes radially outward from the base circle portion 41 </ b> A. The low-speed cam 42 has a base circle portion 42A having the same radius as the base circle portion 41A of the high-speed cam 41 serving as a base, and a radial direction outward from the base circle portion 42A in the radial direction from the nose portion 41B of the high-speed cam 41. And a nose portion 42B formed with a low protruding dimension.

  As shown in FIG. 3, the high-speed cam 41 and the low-speed cam 42 are installed adjacent to each other along the axial direction, and the base circular portions 41A and 42A are continuous surfaces formed flush with each other in the axial direction. ing.

  Further, the nose portions 41B and 42B of the high-speed cam 41 and the low-speed cam 42 are installed in a direction having substantially the same phase. The high-speed cam 41 and the low-speed cam 42 are designed so that the lift timing of the intake valve 13 that operates in accordance with the operation of the crankshaft (not shown) is defined by the installation state with respect to the camshaft 3.

  As shown in FIG. 2 and FIG. 3, a guide groove 43 as a concave portion is formed on the outer peripheral surface of the cam carrier 4 so as to circulate and continue. In the guide groove 43, one of the pair of side walls facing each other is a first switching cam 43A that moves the cam carrier 4 to the first position, and the other of the pair of side walls is the cam carrier 4. It is the 2nd switching cam 43B moved to the 2nd position.

  As shown in FIG. 3, the guide groove 43 includes a maximum groove width portion 43C having a maximum groove width, a minimum groove width portion 43D having a minimum groove width, a maximum groove width portion 43C, and a minimum groove width portion 43D. And a groove width changing portion 43E communicating between the two.

The minimum groove width portion 43D is a groove width through which one of a first switching pin 51 and a second switching pin 52 described later can pass. The maximum groove width portion 43C is formed to have a groove width having a space through which one of the first switching pin 51 and the second switching pin 52 can pass on both outer sides in the groove width direction around the minimum groove width portion 43D. Has been.
(Cam switching part)

  As shown in FIGS. 2, 5, and 8, the cam switching unit 5 includes a first switching pin 51, a second switching pin 52, a gear 53, and the first switching pin 51 on the bottom surface of the head cover 1A. A spring 54 urging in a direction protruding from the plug, plugs 55A and 55B, and a holder member 71.

  5 and 8, the holder member 71 is attached to the head cover 1A. The holder member 71 includes a first housing portion 72 and a second housing portion 73, and the first housing portion 72 and the second housing portion 73 are adjacent to each other along the axial direction of the cam shaft 3. Yes.

  In FIG. 5, a boss portion 1a is formed in the head cover 1A, and a holder member 71 is inserted through the boss portion 1a. A bolt mounting piece 74 is formed on the outer peripheral portion of the holder member 71, and the bolt mounting piece 74 has a bolt insertion hole 74 a through which the bolt 75 is inserted.

  The head cover 1A is formed with a bolt screw hole 1b in which a thread groove is formed on the inner peripheral surface, and the bolt is inserted from below the head cover 1A with the bolt mounting piece 74 in contact with the inner peripheral surface of the head cover 1A. When the bolt 75 is screwed into the bolt screwing hole 1b through the hole 74a, the holder member 71 is attached to the head cover 1A.

  In the first accommodating portion 72 and the second accommodating portion 73, a first switching pin 51 and a second switching pin 52 are accommodated so as to be reciprocally movable in the radial direction of the cam shaft 3, respectively.

  The first switching pin 51 has a first protruding portion 51D that protrudes downward from the lower end of the first switching pin 51. The first protruding portion 51D is formed at the bottom of the first accommodating portion 72. The opening 72a projects from the opening 72a so as to be freely inserted into the guide groove 43, and can contact the second switching cam 43B.

  The second switching pin 52 has a second protruding portion 52D that protrudes downward from the lower end of the second switching pin 52, and the second protruding portion 52D is formed at the bottom of the second accommodating portion 73. The opening 73a projects from the opening 73a so as to be freely inserted into the guide groove 43, and can contact the first switching cam 43A.

  The width of the first projecting portion 51D and the second projecting portion 52D in the direction of the cam shaft 3 is about half the width of the first switching pin 51 and the second switching pin 52 in the direction of the cam shaft 3, respectively. Is formed.

  Further, the central axes L1 and L2 of the first protrusion 51D and the second protrusion 52D in the radial direction of the cam shaft 3 are the radial directions of the cam shaft 3 of the first storage part 72 and the second storage part 73, respectively. Between the central axes L3 and L4.

On the other hand, the first switching pin 51 and the second switching pin 52 are coupled by a coupling mechanism 57 that moves in the opposite directions along the radial direction of the camshaft 3.
The coupling mechanism 57 includes a first rack 51B formed on the side surface of the first switching pin 51, a second rack 52B formed on the second switching pin 52 facing the first rack 51B, A gear 53 that meshes with the first rack 51B and the second rack 52B is provided. As shown in FIG. 5, the first rack 51 </ b> B is formed on the bottom surface of the first recess 51 </ b> A formed on the side surface along the direction in which the first switching pin 51 reciprocates.

  The second rack 51B is formed on the bottom surface of the second recess 52A formed on the side surface along the direction in which the second switching pin 52 reciprocates. As shown in FIG. 5, side walls 51 </ b> C and 51 </ b> C are formed at both ends of the first recess 51 </ b> A in the reciprocating direction so as to contact the gear 53 and restrict the moving range of the first switching pin 51.

  Side walls 52 </ b> C that abut the gear 53 and restrict the movement range of the second switching pin 52 are formed at both ends of the second recess 52 </ b> A in the reciprocating direction.

  Moreover, the 1st accommodating part 72 and the 2nd accommodating part 73 are formed so that it may become substantially parallel, and as shown in FIG. 5, the 1st accommodating part 72 and the 2nd accommodating part 73 are The gear installation space 58 communicates at an intermediate position in the axial direction. The gear installation space 58 communicates with a gear insertion port 59 formed in the holder member 71 (see FIG. 6), and the gear 53 is inserted into the gear installation space 58 through the gear insertion port 59. Yes. And the gear insertion port 59 is closed when the plug 60 which has the rotating shaft 60a which supports the gear 53 rotatably is screwed together.

  As shown in FIG. 8, the upper opening end of the first accommodating portion 72 is closed by a plug 55A, and the upper opening end of the second accommodating portion 73 is screwed into the plug 55B. It is closed by a plug 55B. The plug 55B presses the stopper plate 49 against the plug 55A, and the plug 55A is attached to the first housing portion 72 so as not to come out of the first housing portion 72 by the stopper plate 49.

  A spring 54 is provided between the bottom surface of the plug 55 </ b> B and the second switching pin 52, and the spring 54 urges the second switching pin 52 in a direction in which the second switching pin 52 is inserted into the guide groove 43. Here, the first accommodating portion 72 of the present embodiment is configured to include the plug 55A, and the second accommodating portion 73 is configured to include the plug 55B, and the bottom surface of the plug 55B is The upper surface of the 2nd accommodating part 73 is comprised.

  In FIG. 5, a first locking surface 51E is formed in the lower part of the first switching pin 51 except for the first projecting portion 51D. The first locking surface 51E is a first housing. By contacting the bottom surface of the portion 72, the protruding amount of the first protruding portion 51 </ b> D with respect to the first accommodating portion 72 is regulated. In other words, since the first protrusion 51D constitutes a part of the first switching pin 51, it can be said that the protruding amount of the first switching pin 51 is restricted.

  A second locking surface 52E is formed below the second switching pin 52 excluding the second protrusion 52D, and the second locking surface 52E is a bottom surface of the second housing portion 73. The amount of protrusion of the second protrusion 52D with respect to the second housing part 73 is regulated by contacting the second housing part 73. In other words, since the second protrusion 52D constitutes a part of the second switching pin 52, it can be said that the protruding amount of the second switching pin 52 is restricted.

  As shown in FIG. 4, an oil supply hole 61 is formed in the boss portion 1a of the head cover 1A and the holder member 71. The oil supply hole 61 is a high pressure supplied from a hydraulic actuator or the like (not shown) through a main gallery (not shown). The oil is supplied to the first accommodating portion 72.

  The high-pressure oil supplied from the oil supply hole 61 to the first accommodating portion 72 acts on the first switching pin 51 to move the first switching pin 51 downward in FIG. When the first switching pin 51 moves downward, the gear 53 rotates and the second switching pin 52 moves upward in FIG. 5 against the biasing force of the spring 54, and the first switching pin 51 and The second switching pin 52 moves in the reverse direction.

  In FIG. 6, an oil discharge hole 62a is formed in the second storage portion 73 across the axial direction of the second switching pin 52, and the oil discharge hole 62a and the second storage are formed at the lower end of the plug 55B. An oil discharge hole 62b that communicates with the portion 73 is formed, and the oil inside the second storage portion 73 is discharged through the oil discharge holes 62b and 62a.

  That is, the variable valve apparatus 2 of the present embodiment is configured so that the oil discharge holes 62a and 62b for discharging the oil from the second storage portion 73 are outside the sliding range of the second switching pin 52 in the second storage portion 73. Is formed. The oil discharge holes 62a and 62b are provided above the contact portion between the upper end of the spring 54 and the second accommodating portion 73, that is, above the upper end of the spring 54 and the lower end of the plug 55A.

  6 and 8, an oil discharge hole 62c is formed in the inner peripheral portion of the boss 1a. The oil discharge hole 62c communicates with the oil discharge hole 62a. The oil discharge hole 62c is configured to return the oil discharged from the oil discharge hole 62a into the head cover 1A, and the oil returned to the head cover 1A passes through the inside of the engine below the cylinder head 1 to an oil pan (not shown). Returned to

  Further, the axial direction of the bolt 75 of the present embodiment and the axial direction of the first switching pin 51 and the second switching pin 52 are the same direction, and the direction of oil acting on the first switching pin 51 Is in the same direction as the axial direction of the bolt 75. For this reason, even if high-pressure oil acts on the first switching pin 51, the shearing direction force does not act on the first switching pin 51, and the shearing direction force is prevented from acting in the rotational direction. Is done. Therefore, the fastening force of the bolt 75 can be prevented from being lowered, and the holder member 71 can be stably attached to the head cover 1A over a long period of time.

Next, the operation will be described.
Hereinafter, the switching operation to the high speed cam 41 and the low speed cam 42 of the variable valve operating apparatus 2 according to the present embodiment will be described with reference to FIGS.

  FIG. 9 shows a state where the high speed cam 41 is selected and operated in the variable valve operating apparatus 2. The position of the cam carrier 4 in such a state is defined as a first position. In this state, since the second switching pin 52 is biased by the spring 54 and moved downward, the first switching pin 51 is moved upward by the coupling mechanism 57 and the base of the high-speed cam 41 is moved. The circular portion 41A and the pressed roller 11A of the rocker arm 11 are in contact with each other.

  At this time, the first switching pin 51 is arranged so as to pass through the minimum groove width portion 43D of the guide groove 43 as shown in FIG. At this time, the ball 35 provided on the camshaft 3 side is engaged with the first positioning groove 46 on the cam carrier 4 side.

  When switching from the state in which the high-speed cam 41 is selected to the state in which the low-speed cam 42 is selected (the cam carrier 4 is in the second position) as shown in FIG. High pressure oil is supplied to the unit 72.

  At this time, as shown in FIG. 10, the first switching pin 51 moves downward, and the second switching pin 52 is attached to the spring 54 by the connecting mechanism 57 as the first switching pin 51 moves downward. It moves upward against the force and protrudes from the first accommodating portion 72 so that the first protrusion 51D of the first switching pin 51 is inserted into the guide groove 43.

  That is, with the protrusion of the first protrusion 51D, the gear 53 rotates as the first rack 51B of the first switching pin 51 moves downward, and the second rack 52B is connected to the first rack 51B. By moving upward in the opposite direction, the second protrusion 52D of the second switching pin 52 performs an operation in the direction of retracting into the second accommodating portion 73.

  Since the cam carrier 4 includes a groove width changing portion 43E that communicates between the maximum groove width portion 43C and the minimum groove width portion 43D and bulges in the rotation direction of the cam carrier 4, the first switching pin 51 is provided. When the first protrusion 51D is inserted into the guide groove 43, the first protrusion 51D comes into contact with the groove width changing portion 43E, and an axial force acts on the cam carrier 4.

  For this reason, the cam carrier 4 moves to the second position through the state shown in FIG. At this time, the base circle portion 41A of the high-speed cam 41 and the base circle portion 42A of the low-speed cam 42 slide smoothly with respect to the pressed roller 11A of the rocker arm 11, and as shown in FIG. The base circle portion 42A of the cam 42 comes into contact.

  Thus, when the cam carrier 4 is displaced with respect to the cam shaft 3, the ball 35 on the cam shaft 3 side is disengaged from the first position positioning groove 46 shown in FIG. It will be in the state which moved to and engaged. As a result, the cam carrier 4 is fixed at the position (second position) where the low-speed cam 42 is selected with respect to the cam shaft 3.

  Further, when the low speed cam 42 is selected and the cam carrier 4 is in the second position as described above, the first switching pin 52 is provided in the guide groove 43 until the switching to the high speed cam 41 is performed. The installation is such that it passes through the minimum groove width portion 43D. With such an installation, the first switching pin 52 does not contact the first switching cam 43A and the second switching cam 43B, so that the position of the low-speed cam 42 is maintained and the low-speed cam 42 continues to operate.

  On the other hand, when switching from the low speed cam 42 to the high speed cam 41, the supply of oil from the hydraulic actuator to the oil supply hole 61 is stopped or the hydraulic pressure supplied from the actuator is set to a biasing force smaller than the biasing force of the spring 54. Adjust the oil pressure so that At this time, the second switching pin 52 is urged by the spring 54, and the second projecting portion 52 </ b> D of the second switching pin 52 projects from the second accommodating portion 73.

  As the second protrusion 52D protrudes, the gear 53 rotates as the second rack 52B of the second switching pin 52 moves downward, so that the first rack 51B is in the opposite direction to the second rack 52B. Move upwards. That is, the first protruding portion 51 </ b> D of the first switching pin 51 performs an operation in the direction of retracting into the first accommodating portion 72.

  Then, the cam carrier 4 rotates in a state where the first switching cam 43A of the guide groove 43 is in contact with the second protrusion 52D of the second switching pin 52, so that the cam carrier 4 is in the first position shown in FIG. The cam that contacts the pressed roller 11A of the rocker arm 11 is switched from the low-speed cam 42 to the high-speed cam 41.

  Further, when the second protrusion 52D of the second switching pin 52 protrudes to some extent from the second housing 73, the second locking surface 52E comes into contact with the bottom surface of the second housing 73, The amount of protrusion of the second protrusion 52D with respect to the second housing part 73 is restricted. At this time, since the rotation of the gear 53 is not performed, the upward movement of the first switching pin 51 is also restricted.

  Simultaneously with this operation, in the present embodiment, the side walls 51C, 51C, 52C are provided at both ends of the first recess 51A of the first switching pin 51 and the second recess 52A of the second switching pin 52 in the reciprocating direction. Since the 52C is formed, the side walls 51C and 52C come into contact with the gear 53, and the moving range of the first switching pin 51 and the second switching pin 52 is more reliably regulated.

  Next, the relationship between the movement of the cam carrier 4 in the axial direction and the first switching pin 51 and the second switching pin 52 will be specifically described.

  In the variable valve operating apparatus 2 of the present embodiment, the maximum groove width portion 43C of the cam carrier 4 is first switched to both outer sides (both outer sides in the axial direction of the cam carrier 4) centering on the minimum groove width portion 43D. A groove width having a space through which one of the pin 51 and the second switching pin 52 can pass is formed.

  For this reason, when the cam carrier 4 is in the first position, the second projecting portion 52D of the second switching pin 52 passes through the minimum groove width portion 43D of the guide groove 43 in the axial direction of the cam shaft 3. is there. At this time, before the second protrusion 52D of the second switching pin 52 passes through the minimum groove width part 43D or after the passage, the first protrusion 51D of the first switching pin 51 has the maximum groove width part. 43C can be inserted.

  Here, if the first protrusion 51D of the first switching pin 51 is inserted into the guide groove 43 at a position corresponding to the maximum groove width portion 43C, the cam carrier 4 is moved to the first by the operation described below. The position can be moved to the second position.

  That is, the first projecting portion 51D of the first switching pin 51 moves from the maximum groove width portion 43C to the groove width changing portion 43E by the rotation of the cam carrier 4, and comes into contact with the groove width changing portion 43E so that the cam carrier 4 starts moving to the second position. When the first protrusion 51D of the first switching pin 51 reaches the minimum groove width portion 43D, the movement of the cam carrier 4 to the second position is completed.

  Further, when the cam carrier 4 is in the second position, the second protrusion 52D of the second switching pin 52 is inserted into the guide groove 43 at a position corresponding to the maximum groove width part 43C. The second protrusion 52D of the switching pin 52 can contact the groove width changing portion 43E to move the cam carrier 4 to the first position.

  Thus, according to the variable valve operating apparatus 2 of the present embodiment, the cam switching mechanism that switches between the high-speed cam 41 and the low-speed cam 42 is a single cam that has the first switching cam 43A and the second switching cam 43B as side walls. Since the first switching groove 51 that can contact the second switching cam 43B and the second switching pin 52 that can contact the first switching cam 43B and the first switching cam 43B, There is no need to individually form a guide groove in each of the switching pin 51 and the second switching pin 52. For this reason, the cam switching mechanism for switching between the high-speed cam 41 and the low-speed cam 42 can have a simple structure.

  Further, according to the variable valve operating apparatus 2 of the present embodiment, the first switching pin 51 protrudes from the first housing portion 72 so as to be freely inserted into the guide groove 43 and can contact the first switching cam 43A. The second switching pin 52 has a first protruding portion 51D, and the second switching pin 52 protrudes from the second housing portion 73 so as to be insertable into the guide groove 43, and the second protruding portion 52D that can contact the second switching cam 43B. The center axes L1 and L2 of the first projecting portion 51D and the second projecting portion 52D in the radial direction of the camshaft 3 are the radiuses of the camshaft 3 of the first housing portion 72 and the second housing portion 73. It was installed between the central axes L3 and L4 in the direction.

  Therefore, the first switching pin 51 and the second switching in the axial direction of the cam shaft 3 can be switched between the high speed cam 41 and the low speed cam 42 by moving the cam carrier 4 in the axial direction of the cam shaft 3. The strength and rigidity of the first switching pin 51 and the second switching pin 52 can be increased while keeping the pitch P of the pins 52 constant.

  Further, according to the variable valve apparatus 2 of the present embodiment, the first switching pin 51 and the second switching pin 52 are coupled by the coupling mechanism 57 that moves in the opposite directions along the radial direction of the cam shaft 3. The coupling mechanism 57 includes a first rack 51B formed on the side surface of the first switching pin 51, and a second rack 52B formed on the second switching pin 52 facing the first rack 51B. A gear 53 that meshes with the first rack 51B and the second rack 52B is included.

  Therefore, the first rack 51B and the second rack 52B that require a large installation space for the first switching pin 51 and the second switching pin 52 that can be increased in size by increasing strength and rigidity. And a connecting mechanism 57 including the gear 53 can be easily provided.

  In addition, the first switching pin 51 and the second switching pin 52 are provided on the first protruding portion 51D and the second protruding portion 52D, so that the first switching pin 51 and the second switching pin 52 are provided. The pitch P of the first switching pin 51 and the second switching pin 52 in the axial direction of the camshaft 3 can be kept constant even if the size of the camshaft 3 is increased.

  Moreover, according to the variable valve operating apparatus 2 of the present embodiment, the oil discharge holes 62a and 62b of the second housing portion 73 are provided outside the sliding range of the second switching pin 52, so that the second housing portion 72, the second switching pin 52 can be prevented from being caught by the edge (opening end) of the oil discharge hole 62a when the second switching pin 52 slides. Can be performed smoothly, and the second switching pin 52 can be prevented from being damaged.

  Further, according to the variable valve operating apparatus 2 of the present embodiment, the first switching pin 51 with respect to the first housing portion 72 is in contact with the bottom surface of the first housing portion 72 below the first switching pin 51. A first locking surface 51E for restricting the amount of protrusion of the second housing portion 73 is formed, and a second switching with respect to the second housing portion 73 is brought into contact with the bottom surface of the second housing portion 73 below the second switching pin 52. A second locking surface 52E that restricts the protruding amount of the pin 52 was formed.

  For this reason, when the 1st latching surface 51E of the 1st switching pin 51 contacts the bottom face of the 1st accommodating part 72, the 2nd switching pin 52 becomes the 1st switching pin via the connection mechanism 57. The amount of movement when moving in the opposite direction to 51 can be regulated.

  Therefore, the second switching pin 52 does not move to the oil discharge hole 62a, and the second switching pin 52 can be more effectively prevented from being caught by the edge of the oil discharge hole 62a.

Further, according to the variable valve operating apparatus 2 of the present embodiment, the oil discharge holes 62a and 62b are provided above the upper end of the spring 54 and the lower end of the plug 55A, so that the upper end of the spring 54 is the oil discharge hole 62a. It is possible to prevent the edge from being caught. Therefore, the second switching pin 52 can be smoothly slid and the second switching pin 52 and the spring 54 can be prevented from being damaged.
(Other embodiments)

  Although the embodiment has been described above, the present invention is not limited to this. For example, in the above-described embodiment, the operation in which the first switching pin 51 and the second switching pin 52 move in a staggered direction is performed in the rack and having the first rack 51B and the second rack 52B with the gear 53 interposed therebetween. Although realized by a pinion mechanism, the present invention is not limited to this, and other mechanisms that perform a seesaw operation can of course be used.

  In the present embodiment, the present invention is applied to the two-stage variable valve operating device of the high speed cam 41 and the low speed cam 42. However, like the cam carrier 4A shown in FIG. If the pausing cam 48 has a peripheral surface, a valve pausing function can be realized. With such a configuration, the structure of the cam switching mechanism can be simplified, and the intake valve 13 can be stopped.

  Further, in the variable valve operating apparatus 2 of the present embodiment, the switching pin located at the front is the second switching pin 52 and the switching pin located at the rear is the first switching pin 51 in FIG. The switching pin positioned at the first position may be the first switching pin 51, and the switching pin positioned at the rear may be the second switching pin 52.

  In this case, the oil supply hole 61 is formed in the first housing portion 72 as the second housing portion 73 that houses the first switching pin 51 positioned in the front, and the rear portion is rearward. Oil discharge holes 62 a, 62 b may be formed in the second housing portion 73, with the first housing portion 72 housing the first switching pin 51 positioned at the second housing portion 73 as a new second housing portion 73.

  In the variable valve operating apparatus 2 of the present embodiment, the first housing portion 72 and the second housing portion 73 that are separate from the head cover 1A are fixed to the head cover 1A with bolts 75. 72 and the second accommodating portion 73 may be provided integrally with the head cover 1A, that is, integrally formed.

  In this way, it is not necessary to form the separate first housing portion 72 and second housing portion 73 in the head cover 1A, and the number of parts of the head cover 1A can be reduced.

  In addition to this, since it is unnecessary to provide the head cover 1A with bolts 75 and bolt 75 attachment portions for fixing the first storage portion 72 and the second storage portion 73, the space around the head cover 1A is eliminated. Can be used effectively.

  While embodiments of the invention have been disclosed, it will be apparent to those skilled in the art that changes may be made without departing from the scope of the invention. All such modifications and equivalents are intended to be included in the following claims.

  DESCRIPTION OF SYMBOLS 1 ... Cylinder head, 2 ... Variable valve apparatus, 3, 30 ... Cam shaft, 4, 4A ... Cam carrier, 5 ... Cam switching part, 13 ... Intake valve, 41 ... High speed cam (1st cam), 42 ... Low speed cam (second cam), 43... Guide groove (concave portion), 43 A... Switching cam (first switching cam), 43 B... Switching cam (second switching cam), 51. , 51B ... first rack, 51D ... first protrusion, 52 ... second switching pin, 52B ... second rack, 52D ... second protrusion, 53 ... gear, 55A ... plug (first Accommodating portion), 55B ... plug (second accommodating portion), 57 ... coupling mechanism, 72 ... first accommodating portion, 73 ... second accommodating portion, L1 ... central axis (central axis of the first switching pin) , L2... Central axis (center axis of the second switching pin), L3. (The central axis of the second housing portion)

Claims (3)

A camshaft rotatably supported on the cylinder head;
Provided so as to be coaxial with the camshaft, rotate integrally with the camshaft and movable in the axial direction of the camshaft, and formed on the outer peripheral surface so that the valve operating characteristics are different. A cam carrier installed such that the first cam and the second cam are adjacent to each other;
A cam switching unit that switches between the first cam and the second cam that move the cam carrier in the axial direction of the cam shaft to operate the valve;
The cam carrier is movable between a first position where the valve is operated by the first cam and a second position where the valve is operated by the second cam;
A concave portion is formed on the outer peripheral surface of the cam carrier so as to go around the cam carrier,
In the concave portion, one of the pair of side walls facing each other is a first switching cam that moves the cam carrier to the first position, and the other of the pair of side walls is the cam carrier. A variable valve operating apparatus for an internal combustion engine comprising a second switching cam that moves the valve to the second position,
The cam switching portion is provided in each of the first accommodation portion and the second accommodation portion adjacent to each other along the axial direction of the cam shaft, and the first accommodation portion and the second accommodation portion. A first switching pin and a second switching pin that are reciprocally movable in the radial direction of the shaft,
The first switching pin has a first protruding portion that protrudes from the first housing portion so as to be inserted into the concave shape portion, and is freely contactable with the first switching cam.
The second switching pin has a second protruding portion that protrudes from the second accommodating portion so as to be inserted into the concave shape portion, and is freely contactable with the second switching cam.
The central axis of the first protrusion and the second protrusion in the radial direction of the cam shaft is set between the central axis of the first storage part and the second storage part in the radial direction of the cam shaft. A variable valve operating apparatus for an internal combustion engine, characterized by being installed in The first switching pin and the second switching pin are connected by a connecting mechanism that moves in opposite directions along the radial direction of the cam shaft,
The coupling mechanism includes a first rack formed on a side surface of the first switching pin, a second rack formed on the second switching pin facing the first rack, and the first rack. The variable valve mechanism for an internal combustion engine according to claim 1, further comprising a gear that meshes with the second rack and the second rack. A first locking surface is formed at a lower portion of the first switching pin to contact a bottom surface of the first housing portion and regulate a protruding amount of the first switching pin with respect to the first housing portion. ,
A second locking surface is formed at a lower portion of the second switching pin to contact a bottom surface of the second housing portion and restrict a protruding amount of the second switching pin with respect to the second housing portion. The variable valve mechanism for an internal combustion engine according to claim 1 or 2, characterized in that:

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