JP5101234B2 - 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 valve opening characteristic variable valve operating apparatus, a control member that changes the valve opening characteristic is driven by an actuator. In this actuator, in addition to a drive source such as an electric motor, the drive A reduction mechanism that reduces the force is housed in an integrally molded housing (see Patent Document 1).
JP 2007-16726 A

  However, the housing of the actuator, particularly the housing part of the speed reduction mechanism, has a complicated structure due to a large number of parts such as gears. Therefore, when the housing is formed integrally, the degree of freedom in processing is limited, resulting in structural waste. There is a problem that a large number of such portions are generated, leading to an increase in size and weight of the actuator.

  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 system, there is a problem that a large deviation occurs in the operation of the valve mechanism for each cylinder according to the difference in the distance from the actuator due to the distortion of the shaft. If the center drive system is arranged above the center of the cylinder in the arrangement direction of the cylinders, the above-mentioned problems 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 make the housing shape that keeps the height of the actuator low even if the dimensions are increased, if there are significant restrictions on such a housing shape, the degree of freedom of processing when integrally molding the housing as described above However, there is a problem that it becomes difficult to reduce the size and weight of the actuator.

  The present invention has been devised on the basis of such inventor's knowledge, and the main object of the present invention is a variable valve opening characteristic type configured to be able to reduce the size and weight of the actuator. The object is to provide a 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. ), And a control member (control shaft 20, gear link 21, and roller link 22), and an actuator (14) that drives the control member. As the control member, a plurality of cylinders ( 5) a cylinder-specific control member (roller link 22) provided for each cylinder, and a control shaft (20) extending in the cylinder arrangement direction for operating the cylinder-specific control member in an interlocked manner. an electric motor, a motion transmission means of the control member for driving for transmitting the motion of the electric motor to the control member, a position sensor for detecting the position of said control member, before The movement of the control member and the movement transmission means for detecting the sensor for transmitting to said position sensor, the electric motor, a housing (47) for accommodating the movement transmission means and motion transmission means for said sensor detecting for said control member drive And a central portion of the cylinder in the arrangement direction so that the driving force is transmitted at the central portion of the control shaft on the upper surface of the base plate (13) provided so as to cover the upper side of the valve operating chamber. And rotation shafts of gears (51 to 53, 61 to 63) constituting the electric motor , the motion transmitting means for driving the control member, and the motion transmitting means for detecting the sensor are arranged in the cylinder arrangement direction. 1st, 2nd, 3rd division body which is arrange | positioned so that it may become parallel and the said housing was divided | segmented in the rotating shaft direction of the said electric motor and the said gear Together consists of 81 to 83), the first split body (81) houses a portion of the electric motor and motion transmission means of said control member for driving said second split body (82) A part of the motion transmitting means for driving the control member and a part of the motion transmitting means for detecting the sensor are accommodated, and the position sensor is disposed on the side where the third divided body (83) is opposite to the electric motor. holds to accommodate a portion of the motion transmitting means for the sensor detection, a groove which liquid packing is filled in the bonding surfaces of the three split bodies (111, 112) are formed, it is filled in the groove The divided bodies were joined to each other with liquid packing (113, 114).

  According to this, since the housing of the actuator is divided into a plurality of divided bodies, the degree of freedom in processing at the time of manufacture is improved, so that structurally useless parts are eliminated, and the plurality of divided bodies are made of liquid packing. Since they are joined to each other, the number of parts required for joining such as fastening bolts can be reduced together with the sealing effect, so that the actuator can be reduced in size and weight.

Furthermore , the problem that occurs in the case of the side drive system in which the actuator is arranged on the side of the cylinder bed, that is, the influence of the distortion of the control shaft, the operation of the valve mechanism for each cylinder according to the difference in distance from the actuator. Problems that cause large deviations can be avoided.

  In this case, the actuator may be arranged on a plate extending above the valve operating device, and the rotation shaft of the electric motor serving as the drive source, the support shaft of the gear that constitutes the speed reduction mechanism, etc. are attached to the plate. If it arrange | positions in the direction which follows, the height of an actuator can be restrained low. Furthermore, if a plurality of divided bodies constituting the housing are divided in the axial direction of the rotating shaft of the electric motor and the support shaft of the gear, it is easy to eliminate structurally useless parts and to assemble easily. become.

  As described above, according to the present invention, since the actuator housing is divided into a plurality of divided bodies, the degree of freedom in processing at the time of manufacture is improved. Since the bodies are joined to each other by liquid packing, the number of parts required for joining, such as fastening bolts, can be reduced, so that the actuator can be reduced in size and weight.

  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 operating mechanisms 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 rolling 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 a main part of the actuator 14 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 an exploded perspective view of the actuator 14 shown in FIG.

  As shown in FIG. 4, the actuator 14 includes an electric motor (drive source) 41 that drives the gear link 21, and a link drive gear mechanism (for driving a control member) that transmits the movement of the electric motor 41 to the gear link 21. (Movement transmission means) 42, 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 (sensor detection) for transmitting the movement of the gear link 21 to the position sensor 43. Motion transmission means) 44.

  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 first gear 51 and a second gear 52 for driving a link are accommodated in an empty space 92 defined between the first divided body 81 and the second divided body 82.

  In the third divided body 83, as shown in FIG. 6, a vacant chamber 86 having a circular cross section is defined on the side of the position sensor 43. The vacant chamber 86 includes a detection unit 65 of the position sensor 43 and the vacant chamber 86. A sensor engaging portion 66 that engages with is housed. A bearing holding portion 87 that holds the outer ring of the bearing 72 of the third gear 63 for sensor detection is provided on the side opposite to the position sensor 43.

  In the second divided body 82, an empty chamber 88 having a circular cross section is defined, and in this empty chamber 88, the third gear 63 for sensor detection held in the third divided body 83 and its The bearing 72 and the bearing holding part 87 are accommodated.

  As shown in FIG. 7, a bearing holding portion 90 that holds the outer ring of the bearing 57 of the second gear 52 for link driving and the third gear 53 is provided on the outer peripheral side of the second divided body 82. A bearing housing hole 94 is formed in the bearing holding portion 90, and the bearing 57 is fixed to the second divided body 82 by press-fitting the bearing 57 in the axial direction.

  Further, a bearing holding portion 89 that holds the bearings 69 of the first gear 61 and the second gear 62 for sensor detection is provided on the outer peripheral side of the second divided body 82. A housing recess 93 is formed, and the bearing 69 is fixed to the second divided body 82 by press-fitting the bearing 69 in the axial direction.

  The first, second, and third divided bodies 81, 82, and 83 are fastened to each other by bolts 101 and 102, and the first divided body 81 has screw holes 103 into which the bolts 101 are screwed. The second divided body 82 is provided with a bolt insertion hole 104 through which the bolt 101 is inserted, and a screw hole 105 into which the bolt 102 is screwed. The third divided body 83 is inserted with the bolt 102. The bolt insertion hole 106 is opened. These screw holes 103 and 105 and bolt insertion holes 104 and 106 are formed in the axial direction of the gears 51 to 53 and 61 to 63.

  The bolts 101 that fasten the first and second divided bodies 81 and 82 are arranged in a pair on the left and right sides of the center position of the split surface, but at a position shifted upward from the center position of the split surface. Has been placed. The bolts 102 for fastening the second and third divided bodies 82 and 83 are also arranged in a pair on the left and right sides with the center position of the divided surface interposed therebetween, but are arranged at positions shifted downward from the center position of the divided surface. Has been.

  The first, second, and third divided bodies 81, 82, and 83 are joined to each other by liquid packing, and the surface of the first divided body 81 that faces the second divided body 82 is disposed on the surface. A groove 111 filled with liquid packing is formed so as to surround the empty chamber 92. A groove 112 filled with a liquid packing is formed on the surface of the second divided body 82 facing the third divided body 83 so as to surround the empty space 88, the bearing accommodating recess 93, and the bearing accommodating hole 94. ing.

  Therefore, as shown in FIG. 5, in the assembled state of the first and second divided bodies 81 and 82, the liquid packing 113 filled in the groove 111 of the first divided body 81 is the first and second divided bodies. 81 and 82 are joined to each other, and as shown in FIG. 6, in the assembled state of the second and third divided bodies 82 and 83, the liquid packing 114 filled in the groove 112 of the second divided body 82 The first and second divided bodies 81 and 82 are joined to each other.

  Due to the adhesive force of the liquid packings 113 and 114, the number of bolts 101 and 102 for fastening the divided bodies 81, 82, and 83 is reduced to two each, and they are arranged at positions shifted from the center position of the dividing surface. Also, the divided bodies 81, 82, 83 can be reliably joined.

  The liquid packing is preferably made of a silicone polymer material that exhibits the required adhesive strength and is excellent in heat resistance and oil resistance.

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 disassembled perspective view of the actuator shown in FIG.

Explanation of symbols

2 Valve 5 Cylinder 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 (movement transmitting means for driving control member)
61-63 Sensor detection gear (motion detection means for sensor detection)
81-83 Divided body 101/102 Bolt 111/112 Groove 113/114 Liquid packing

Claims (1)

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,
As the control member, a control member for each cylinder provided for each of a plurality of cylinders, and a control shaft extending in the arrangement direction of the cylinders for operating the control member for each cylinder in an interlocked manner,
The actuator includes an electric motor, a movement transmitting means for driving a control member that transmits the movement of the electric motor to the control member, a position sensor that detects a position of the control member, and a movement of the control member in the position. A motion transmission means for sensor detection transmitted to the sensor, a housing for housing the electric motor , a motion transmission means for driving the control member, and a motion transmission means for sensor detection ;
This actuator is arranged at the center of the cylinder arrangement direction so that the driving force is transmitted at the center of the control shaft on the upper surface of the base plate provided so as to cover the upper side of the valve operating chamber, and The electric motor , the motion transmission means for driving the control member, and the rotation shaft of the gear constituting the motion transmission means for detecting the sensor are arranged so as to be parallel to the arrangement direction of the cylinders,
The housing is composed of three divided bodies of first, second, and third divided in the direction of the rotation axis of the electric motor and the gear, and the first divided body is the electric motor and the control. A part of the motion transmission means for driving the member is housed, and the second divided body houses a part of the motion transmission means for driving the control member and a part of the motion transmission means for detecting the sensor , The third divided body holds the position sensor on the side opposite to the electric motor and accommodates a part of the motion detecting means for detecting the sensor , and the joint surface of these three divided bodies is filled with liquid packing A valve opening characteristic variable valve operating apparatus, wherein a groove is formed, and the divided bodies are joined to each other by a liquid packing filled in the groove.

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