JP4870061B2 - Variable valve opening characteristics valve gear - Google Patents

Description

  The present invention relates to a valve opening characteristic variable valve operating device that can change valve opening characteristics such as a lift amount of a valve in accordance with an operation state.

  In recent years, an increasing number of internal combustion engines such as gasoline engines and diesel engines are equipped with various valve opening characteristics variable valve operating devices in order to improve output and fuel consumption, reduce harmful exhaust gas components, and the like. As this type of valve opening characteristics variable type valve operating device, there is a conventional one that switches between a low speed type cam and a high speed type cam according to the operating condition, but in recent years, further improvement of transient characteristics and reduction of throttle etc. have been realized. In order to achieve this, there has been a continuous change in valve opening characteristics (valve lift and valve timing).

  In this type of variable valve opening characteristic valve operating device, a control member that changes the valve opening characteristic is driven by an actuator having a drive source such as a hydraulic mechanism or an electric motor (Patent Document 1). 2).

JP 2000-54815 A JP 2007-16726 A

  However, when an electric motor is used as the actuator, heat generation during driving is unavoidable, and the efficiency decreases when the temperature of the electric motor increases due to this heat generation. Therefore, cooling is required to suppress the temperature rise. .

  Further, in the variable valve opening characteristic type valve operating apparatus, the valve operating mechanism for each cylinder is interlocked via a shaft extending in the cylinder arrangement direction, but the actuator is arranged on the side of the cylinder bed. In the side drive method, there is a problem that a large deviation occurs in the operation of the valve mechanism for each cylinder due to the difference in the distance from the actuator due to the distortion of the shaft. Thus, if the center driving method is used in which the actuator is arranged at the center in the arrangement direction of the cylinders, the above problem can be improved.

  However, in this center drive system, the height of the actuator has a large effect on the overall height of the engine, including accessories, so if there is a limit on the overall height of the engine, Although it is desirable to have a housing shape in which the height of the actuator is kept low even if the dimensions are increased, such a housing shape, combined with the fact that the plate to be mounted is flat, reduces the contact area with the plate. Since it becomes large, heat dissipation is reduced, and the internal temperature distribution becomes non-uniform, which causes a problem that the influence of thermal stress becomes significant.

  It is conceivable to provide a water-cooled or oil-cooled cooling device for such a problem of the temperature rise of the actuator, but this has a problem that the manufacturing cost is greatly increased, and a radiating fin is provided on the housing. Although it may be provided, the manufacturing cost increases and the problem of uneven temperature distribution cannot be sufficiently improved.

  The present invention has been devised based on the knowledge of the inventor as described above, and its main purpose is to suppress the decrease in efficiency due to the temperature rise of the actuator without increasing the manufacturing cost. Another object is to provide a variable valve opening characteristic valve operating device.

In order to solve such a problem, in the valve opening characteristic variable valve operating apparatus according to the present invention, as shown in claim 1, a valve (2 ) provided in the valve operating chamber (10) for intake or exhaust. ) Control member (control shaft 20, gear link 21, and roller link 22) for changing the valve opening characteristics, and an actuator (14) for driving the control member. A motor (41), a power transmission member (link driving gears 51 to 53) for transmitting the driving force of the electric motor to the control member, and a housing (47) for housing the electric motor and the power transmission member. with, disposed on a base plate which is provided so as to cover the upper side of the valve chamber (13), said housing lower surface side of the portion where the power transmission member is accommodated A contact surface (107) that contacts the mounting surface (13a) of the base plate, and the control member (gear link 21) and the power transmission member (link drive) are respectively provided on the contact surface and the mounting surface of the base plate. An opening (89, 101) for connecting to the gear 53) is opened, sealing means (O-ring 105) is provided so as to surround the opening, and the housing accommodates the electric motor. A mounting portion (94/95) that contacts the mounting surface of the base plate is provided on the lower surface side of the portion, and the seating surface (94a / 95a) side of the mounting portion protrudes in a boss shape, and the bottom wall portion (112) wherein the outer surface step is formed between the abutment surface between the mounting surface of the base plate and the bottom wall portion of the outer surface, even gap cooling air flows is to be defined And the. In particular, as shown in claim 2, the control member (gear link 21) is provided so as to rotate around a horizontal axis in which the cylinders (5) are arranged, and the actuator is provided with an output of the electric motor. It is good to arrange | position so that a shaft (45) and the rotating shaft of the said control member may become parallel.

According to this, heat can be radiated from the lower side facing the mounting surface of the base plate as well as the side and upper side of the housing of the actuator, so that the heat radiating area is increased and the temperature rise of the actuator can be suppressed. Furthermore, since heat is dissipated over the entire circumference of the housing of the actuator, the internal temperature distribution can be made uniform and the influence of thermal stress can be suppressed. And , forming the housing so that the gap through which the cooling air flows is defined does not increase the number of manufacturing steps so much, so that an increase in manufacturing cost can be suppressed.

Further, the sealing means can prevent foreign matter from entering the actuator housing and the valve operating chamber. The peripheral portions of the openings provided in the housing and the base plate are brought into contact with each other. Since the power transmission member is disposed in these portions, the influence on the temperature rise of the electric motor is small.

As described above, according to the present invention, heat can be radiated from the lower side facing the mounting surface of the base plate as well as the side and upper side of the actuator housing, so that the heat radiating area is increased and the temperature rise of the actuator is suppressed. Can do. Furthermore, since heat is dissipated over the entire circumference of the housing of the actuator, the internal temperature distribution can be made uniform and the influence of thermal stress can be suppressed. And , forming the housing so that the gap through which the cooling air flows is defined does not increase the number of manufacturing steps so much, so that an increase in manufacturing cost can be suppressed.

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

  FIG. 1 is a perspective view showing an upper portion of an engine according to the present invention. FIG. 2 is a perspective view showing the variable valve opening characteristic valve operating device for the engine shown in FIG. FIG. 3 is a longitudinal sectional view showing an operation state of the valve opening characteristic variable valve operating apparatus shown in FIG.

  As shown in FIG. 1, this engine is an in-line four-cylinder engine mounted on an automobile. The cylinder head 1 includes two exhaust valves 2 for each cylinder 5, As a valve operating mechanism for driving, a camshaft 4 provided with a cam 3, a rocker arm 6 interposed between the valve 2 and the cam 3, and a valve spring 7 for constantly urging the valve 2 in the closing direction are provided. Yes.

  On the intake side, two intake valves 8 are provided for each cylinder, and a camshaft, a rocker arm, and a valve spring (not shown) are provided as valve gears for driving the valves. ing.

  The cam shaft 4 is rotatably supported by the cam holder 11. The cam holder 11 is provided so as to partition the valve operating chamber 10 for each cylinder 5 and is fastened and fixed to the upper surface of the cylinder head 1 with bolts.

  This engine is equipped with a valve opening characteristic variable valve operating device that variably controls the lift amount of the exhaust valve 2. This variable valve opening characteristic type valve operating apparatus has an actuator 14 installed on the upper surface of a base plate 13 provided so as to cover the upper side of the valve operating chamber 10 and a link mechanism driven by the actuator 14. Yes. It is also possible to apply a valve opening characteristic variable valve operating device having a similar mechanism to the intake valve 8.

  As shown in FIG. 2, the link mechanism of the variable valve opening characteristic valve operating device is supported by a control shaft (control member) 20 extending in the lateral direction and a cam holder 11 so as to be rotatable, and the control shaft 20 A gear link (control member) 21 that is rotatably held, and a roller link (control member) 22 that is swingably held by the control shaft 20 and that has a free end interposed between the cam 3 and the rocker arm 6. have.

  The roller link 22 is provided for each cylinder, and operates in conjunction with the turning of the control shaft 20 accompanying the rotation of the gear link 21, and the valve 2 according to the displacement of the swing fulcrum of the roller link 22 caused thereby. The lift amount is changed. The control shaft 20 is rotatably supported by the cam holder 11 via the link holder 30. The rotation center lines of the gear link 21 and the roller link 22 are parallel to each other.

  The gear link 21 extends in an arc shape in the circumferential direction from the free end side of the arm portion 24 that rotates around the support shaft 23 provided in the cam holder 11, and serves as a gear on the actuator 14 side. The gear portion 25 is engaged with the gear portion 25 and is rotated by the driving force of the actuator 14. A shaft holder 26 is formed on the free end side of the arm portion 24 to hold the control shaft 20 in a rotatable manner.

  The roller link 22 has a base portion 28 that is fitted to the control shaft 20 and serves as a rocking fulcrum, and a pair of arm portions 29 extending from the base portion 28. At the tip of the arm portion 29, there are a roller 31 that is in rolling contact with the cam 3 of the camshaft 4, and a roller shaft 32 that is in contact with the slipper surface of the rocker arm 6.

  The rocker arm 6 includes a base portion 35 rotatably supported by a rocker shaft 34 held by the cam holder 11, and a pair of arm portions 36 extending from the base portion 35, and the pair of arms As shown in FIG. 3, each of the portions 36 is provided with a tip portion 38 that presses the stem end 37 of the valve 2 and an adjustment screw 39 that adjusts its position.

  In the valve opening characteristic variable valve operating apparatus configured as described above, the gear link 21 becomes a swing fulcrum of the roller link 22 as it rotates about the support shaft 23 (see FIG. 2). When the control shaft 20 is displaced, the lift amount of the valve 2 changes, and the lift amount of the valve 2 can be adjusted steplessly according to the rotation angle position (link angle) of the gear link 21.

  When reducing the valve lift during idling or the like, the gear link 21 is set to the minimum lift position (for example, link angle = 0 degree) shown in FIG. 3A, and in this case, it becomes the swing fulcrum of the roller link 22. Even if the control shaft 20 is positioned above the rocker arm 6 and the roller 31 is pushed down by the cam 3, the roller shaft 32 rolls along the slipper surface 33 as indicated by the arrow, so that the rocker arm 6 swings. (That is, the lift amount of the valve 2) is reduced.

  On the other hand, when increasing the valve lift during high load operation or the like, the gear link 21 is set to the maximum lift position (for example, link angle = 60 degrees) shown in FIG. 3B, and in this case, the roller link 22 is swung. When the control shaft 20 serving as a fulcrum is located on the side of the rocker arm 6 and the roller 31 is pushed down by the cam 3, the roller shaft 32 hardly rolls along the slipper surface 33. The amount increases.

  4 is a cross-sectional view of the main part of the actuator shown in FIG. FIG. 5 is a cross-sectional view taken along line VV in FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. FIG. 7 is a side view of the actuator shown in FIG. FIG. 8 is a perspective view showing the bottom side of the actuator shown in FIG. FIG. 9 is a perspective view showing a state in which a head cover is attached to the upper part of the engine shown in FIG.

  As shown in FIG. 4, the actuator 14 includes an electric motor (drive source) 41 that drives the gear link 21, a link drive gear mechanism 42 that transmits the movement of the electric motor 41 to the gear link 21, and the gear link 21. A position sensor 43 (see FIG. 1) for detecting the angular position (link angle) of the gear link 21 and a sensor detection gear mechanism 44 for transmitting the movement of the gear link 21 to the position sensor 43.

  The electric motor 41 is a brushless motor. In the engine ECU, the target lift amount of the valve 2 set based on various operation information such as the depression amount of the throttle pedal and the coolant temperature by the driver, that is, the rotation of the gear link 21. The drive current of the electric motor 41 is controlled so that the detection position of the position sensor 43 coincides with the moving angle position (link angle).

  As shown in FIG. 5, the link driving gear mechanism 42 includes a first gear 51 provided on the output shaft 45 of the electric motor 41, a second gear 52 that meshes with the first gear 51, and the second gear 52. The gear 52 has a third gear 53 provided coaxially and relatively non-rotatably. The third gear 53 meshes with the gear link 21, so that the driving force of the electric motor 41 is in two stages. It is decelerated and transmitted to the gear link 21.

  The second gear 52 and the third gear 53 for link driving are connected by a shaft 55, and the shaft 55 is supported by the housing 47 via bearings 56 and 57.

  As shown in FIG. 6, the sensor detection gear mechanism 44 includes a first gear 61 that meshes with the gear link 21, a second gear 62 that is provided coaxially with the first gear 61 and is relatively non-rotatable, A third gear 63 that meshes with the second gear 62 is provided, and the sensor engaging portion 66 that engages with the detecting portion 65 of the position sensor 43 rotates integrally with the third gear 63. Thus, the angular position (link angle) of the gear link 21 is detected by the position sensor 43.

  The position sensor 43 is a so-called hall sensor, and a hall element, a permanent magnet, a control board, and the like for detecting the rotation of the detection unit 65 are accommodated in the housing.

  The first gear 61 and the second gear 62 for sensor detection are connected by a shaft 68, and the shaft 55 is supported by the housing 47 via a bearing 69. The sensor detection third gear 63 is connected to one end of the shaft 71, and the sensor engaging portion 66 is connected to the other end of the shaft 71. The shaft 71 is connected to the housing 47 via a bearing 72. It is supported.

  As shown in FIG. 7, the housing 47 of the actuator 14 includes first, second, and third divided bodies 81, 82, and 83 divided in the axial direction of gears 51 to 53 and 61 to 63. Has been. Each of the divided bodies 81, 82, 83 is manufactured by casting a metal material such as an aluminum alloy.

  As shown in FIG. 5, the first divided body 81 is provided with a bearing holding portion 85 that holds the electric motor 41 and holds the bearings 56 of the second gear 52 and the third gear 53 for link driving. It has been. A vacant space 88 defined between the first divided body 81 and the second divided body 82 accommodates a first gear 51 and a second gear 52 for link driving. The second divided body 82 is provided with a bearing holding portion 86 that holds the bearings 57 of the second gear 52 and the third gear 53 for driving the link. As shown in FIG. A bearing holding portion 87 that holds the bearings 69 of the first gear 61 and the second gear 62 is provided.

  As shown in FIG. 5, an opening 89 is formed in the joint portion between the first divided body 81 and the second divided body 82 on the side facing the base plate 13, and the gear link 21 is formed in the opening 89. Inserted and meshed with the third gear 53 for link driving. Further, the second gear 52 protrudes from the opening 89. Further, as shown in FIG. 6, the first gear 61 for sensor detection protrudes from the opening 89 and meshes with the gear link 21.

  As shown in FIG. 7, the base plate 13 on which the actuator 14 is installed receives the second gear 52 for driving the link protruding from the actuator 14 side and the bearing holding portions 85 and 86, and the gear of the gear link 21. An opening 101 is opened to mesh the portion 25 with the third gear 53 for driving the link on the actuator 14 side and the first gear 61 for sensor detection.

  The housing 47 of the actuator 14 is in contact with the base plate 13 at the periphery of the opening 101 of the base plate 13, and an O-ring (seal means) 105 is provided so as to surround the opening 101. The O-ring 105 is loaded in a groove 106 formed in the base plate 13, pressed against the contact surface 107 of the housing 47 with respect to the base plate 13, and sealed in a state where the inside of the housing 47 and the valve operating chamber 10 are communicated. To do.

  The housing 47 of the actuator 14 is fastened and fixed to the base plate 13 by a plurality of bolts 91 as shown in FIG. Here, the first divided body 81 is formed in a state in which mounting portions 94 and 95 in which bolt insertion holes 92 and 93 into which two bolts 91 are inserted on the left and right sides are opened protrude sideways. . Further, the second divided body 82 is also formed with a mounting portion 97 having a bolt insertion hole 96 through which one bolt 91 is inserted on each of the left and right sides protruding in a lateral direction.

  On the side facing the base plate 13 in the first divided body 81, a recess 111 is provided, and in this recess 111, the fastening seat surfaces 94 a and 95 a of the mounting portions 94 and 95 and the O-ring 105 are arranged. The mounting surface 94a / 95a side of the mounting portion 94/95 protrudes like a boss while the outer surface of the bottom wall 112 is retracted upward while leaving the contact surface 107 to be A step is formed between the outer surface of the wall portion 112 and the contact surface 107.

  As shown in FIG. 7, the recess 111 is provided so as to substantially correspond to the portion in which the electric motor 41 is accommodated, and the fastening seat surfaces 94 a and 95 a of the mounting portions 94 and 95 and the O-ring 105 are provided. Only the contact surface 107 to be disposed contacts the mounting surface 13a of the substantially flat base plate 13, and cooling air is provided between the mounting surface 13a of the base plate 13 and the outer surface of the bottom wall portion 112 of the first divided body 81. Is formed, and heat can be radiated from the lower side facing the mounting surface 13a of the base plate 13 along with the side and upper side of the first divided body 81, so that the heat radiating area is increased and the electric motor is increased. The efficiency reduction due to the temperature rise of 41 can be suppressed, and furthermore, heat is dissipated over the entire circumference of the first divided body 81, so that the internal temperature distribution is made uniform and the influence of thermal stress is suppressed. Can do.

  As shown in FIG. 1, the actuator 14 is installed on a base plate 13 disposed so as to cover the upper side of the valve operating chamber 10, and here, as shown in FIG. 9, a head cover that covers the valve operating chamber 10. The head cover 131 is provided so as to surround the actuator 14, and the actuator 14 and the base plate 13 in the vicinity thereof are exposed. Since air circulates in the periphery, and particularly in the gap between the actuator 14 and the base plate 13, heat dissipation of the actuator 14 is promoted.

It is a perspective view which shows the upper part of the engine by this invention. It is a perspective view which shows the valve opening characteristic variable type valve operating apparatus of the engine shown in FIG. FIG. 3 is a longitudinal sectional view showing an operation state of the valve opening characteristic variable valve operating apparatus shown in FIG. 2. It is principal part sectional drawing of the actuator shown in FIG. It is sectional drawing cut | disconnected by the VV line | wire of FIG. It is sectional drawing cut | disconnected by the VI-VI line of FIG. It is a side view of the actuator shown in FIG. It is a perspective view which shows the bottom face side of the actuator shown in FIG. It is a perspective view which shows the state which attached the head cover to the upper part of the engine shown in FIG.

Explanation of symbols

2 Valve 10 Valve chamber 13 Base plate, 13a Mounting surface 14 Actuator 20 Control shaft (control member)
21 Gear link (control member)
22 Roller link (control member)
41 Electric motor (drive source)
42 Link drive gear mechanism 43 Position sensor 44 Sensor detection gear mechanism 47 Housing 51 to 53 Link drive gear (power transmission member)
61-63 Sensor detection gears 81-83 Split body 89 Opening 91 Bolt 92/93/96 Bolt insertion hole 94/95/97 Mounting portion 94a / 95a Tightening seat surface 101 Opening 105 O-ring (sealing means)
106 Groove 107 Contact surface 111 Recess 112 Bottom wall

Claims (2)

A control member that is provided in the valve operating chamber and changes a valve opening characteristic of a valve that performs intake or exhaust, and an actuator that drives the control member,
The actuator comprises an electric motor as a driving source, a power transmitting member for transmitting the driving force of the electric motor to the control member, and a housing for accommodating the electric motor and the power transmission member, said valve-operating chamber On the base plate provided to cover the upper side of the
The housing includes a contact surface that contacts a mounting surface of the base plate on a lower surface side of a portion in which the power transmission member is accommodated, and the control member and the mounting surface of the base plate are respectively provided on the contact surface and the mounting surface of the base plate. An opening for connecting the power transmission member is established, and a sealing means is provided so as to surround the opening,
The housing includes a mounting portion that contacts the mounting surface of the base plate on a lower surface side of a portion in which the electric motor is accommodated, and a seating surface side of the mounting portion protrudes in a boss shape, and an outer surface of the bottom wall portion A step is formed between the contact surface, and a gap through which cooling air flows is defined between the mounting surface of the base plate and the outer surface of the bottom wall portion. Variable valve opening characteristics valve operating device. The control member is provided so as to rotate around a horizontal axis in which the cylinders are arranged,
The variable valve opening characteristic valve operating device according to claim 1, wherein the actuator is arranged so that an output shaft of the electric motor and a rotation shaft of the control member are parallel to each other .

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