JP2008111446A - Actuator apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent operation noise and friction caused by each component of a screw transmission means based upon alternating torque transmitted via a control shaft. <P>SOLUTION: The screw transmission means 37 for transmitting torque of an electric motor 36 to the control shaft 32 changing a valve lift amount of an intake valve 2 via a variable mechanism 4 by rotating is provided with a rotatably borne ball screw shaft 45, a ball nut 46 screwed onto an outer circumference of the ball screw shaft, a link arm 47 connected to the control shaft, and a link member 48 with one end side linked in a biased position with respect to an axis of the control shaft in the link arm and another end side rotatably connected to the ball nut. It is composed such that lubricating oil is led out from an engine through the control shaft, the lubricating oil flows along the link member via the link arm, and the lubricating oil is supplied to a connecting portion of the like arm and the link member. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an actuator device used as a drive mechanism such as a variable valve device that variably controls the valve lift amount and operating angle of an intake valve and an exhaust valve of an internal combustion engine in accordance with the engine operating state.

  As actuator devices used in conventional variable valve gears, those described in the following patent documents filed earlier by the present applicant are known.

  Briefly, this variable valve operating apparatus is arranged coaxially with a drive shaft that is rotationally driven from a crankshaft of an engine via a sprocket, with a certain clearance around the drive shaft, and relative to the drive shaft. A rotatable camshaft, a variable mechanism that is interposed between the drive shaft and the camshaft, and variably controls the opening / closing timing of the intake valve by changing the rotational phase of both according to the engine operating state, and the variable And an actuator device for driving the mechanism.

  This actuator device has an electric motor and a worm gear mechanism as a speed reducing mechanism that reduces the rotational speed of the electric motor and transmits it to the control shaft.

  Then, the electric motor is rotated in one direction by a control signal from the controller in accordance with the change in the engine operating state, and the control shaft is rotated in the same direction via the worm gear mechanism, whereby the second eccentric cam and the first The eccentric cam is rotationally controlled to a predetermined angle. As a result, the opening and closing timing of the intake valve can be varied by changing the rotational phase of the drive shaft and camshaft by controlling the center of the annular disc from the center of the drive shaft to be eccentric or concentric with the swing of the disc housing. It is designed to improve engine performance from low engine speed to high engine speed.

Also, during this engine operation, positive and negative alternating torque generated in the camshaft due to the spring force of the valve spring is transmitted to the control shaft via each flange portion of the variable mechanism, the disk housing, etc. Torque is reduced between the worm wheel and the worm gear by using the irreversibility of the worm gear mechanism, thereby reducing the driving load of the actuator.
JP 2000-234507 A (see paragraph numbers 0031 to 0034, FIG. 1 and the like)

  However, in this conventional actuator device, as described above, although the alternating torque transmitted from the camshaft can be reduced between the worm wheel and the worm gear by utilizing the irreversibility of the worm gear mechanism, Due to the structure of the worm gear mechanism, the backlash gap between the worm wheel and the worm gear cannot be set sufficiently small. For this reason, it is easy to generate a collision sound due to the alternating torque between the tooth surfaces of the worm wheel and the worm gear.

  In addition, since the worm wheel and the worm gear transmit torque when one tooth part comes into contact with each other, the surface pressure between the tooth surfaces facing each other is increased, and wear is likely to occur. Various technical problems such as a decrease in performance are incurred.

  The present invention has been devised in view of the actual state of the conventional actuator device, and in particular, the lubricating oil led out from the engine through the control shaft flows through the link member via the linkage arm. It is characterized by that.

  Therefore, according to the present invention, since the lubricating oil is sufficiently supplied to the respective components of the screw transmission means, the components between the components due to the alternating torque transmitted from the valve operating mechanism to the screw transmission means via the control shaft. The rattling noise can be effectively suppressed by the lubricating oil, and the occurrence of wear between the components can be prevented by improving the lubricating performance.

  In particular, the lubricating oil derived from the engine is not simply supplied to the screw transmission means but is supplied through the link member via the linkage arm. Lubrication performance can be improved.

  Hereinafter, an embodiment in which an actuator device according to the present invention is applied to a variable valve device for an internal combustion engine will be described in detail with reference to the drawings. In this embodiment, the variable valve operating device is applied to the intake valve side, has two intake valves per cylinder, and variably controls the valve lift amount of the intake valves according to the engine operating state.

  That is, the variable valve operating apparatus is slidably provided on the cylinder head 1 via a valve guide (not shown) as shown in FIGS. 6 to 9 and is urged in the closing direction by the valve springs 3 and 3. A pair of intake valves 2, 2, a variable mechanism 4 that variably controls the valve lift amount of each intake valve 2, 2, a control mechanism 5 that controls the operating position of the variable mechanism 4, and the control mechanism 5 that rotates And a drive mechanism 6 which is an actuator device for driving.

  The variable mechanism 4 includes a hollow drive shaft 13 rotatably supported by a bearing 14 above the cylinder head 1, a drive cam 15 that is an eccentric rotary cam fixed to the drive shaft 13 by press fitting, and the like. The two which are supported by the outer peripheral surface of the drive shaft 13 so that rocking is possible, and are slidably contacted with the valve lifters 16 and 16 provided at the upper ends of the intake valves 2 and 2 to open the intake valves 2 and 2. The rocking cams 17 and 17 are linked to each other between the drive cam 15 and the rocking cams 17 and 17, and a transmission mechanism that transmits the rotational force of the drive cam 15 as the rocking force of the rocking cams 17 and 17 is provided. ing.

  As shown in FIG. 6, the drive shaft 13 is disposed along the longitudinal direction of the engine, and a driven sprocket (not shown) provided at one end, a timing chain wound around the driven sprocket, and the like. Rotational force is transmitted from the crankshaft of the engine via this, and this rotational direction is set in the clockwise direction (arrow direction) in the figure.

  As shown in FIG. 7A, the bearing 14 is provided at the upper end portion of the cylinder head 1 to support the upper portion of the drive shaft 13, and the control shaft is provided at the upper end portion of the main bracket 14a and will be described later. The brackets 14a and 14b are fixed together from above by a pair of bolts 14c and 14c.

  The drive cam 15 has a substantially ring shape, and includes an annular cam main body and a cylindrical portion integrally provided on the outer end surface of the cam main body, and a drive shaft insertion hole is formed through the inner shaft. In addition, the axis Y of the cam body is offset from the axis X of the drive shaft 13 in the radial direction by a predetermined amount β. The drive cam 15 is press-fitted and fixed to the drive shaft 13 through one of the drive shaft insertion holes on the outer side that does not interfere with the valve lifters 16 and 16, and the outer peripheral surface of the cam body is an eccentric circle. The cam profile is formed.

  The valve lifters 16 and 16 are formed in a cylindrical shape with a lid, are slidably held in the holding holes of the cylinder head 1, and have a flat upper surface on which the swing cams 17 and 17 are in sliding contact. Yes.

  As shown in FIGS. 6 and 7, both the swing cams 17 have substantially the same raindrop shape, and are integrally provided at both ends of the annular camshaft 20. Is rotatably supported by the drive shaft 13 via the inner peripheral surface. In addition, a pin hole is formed through one end of the cam nose portion 21 side, and a cam surface 22 is formed on the lower surface. The base circle surface on the camshaft 20 side, and the cam nose portion 21 side from the base circle surface A ramp surface extending in an arc shape, and a lift surface connected to the top surface of the maximum lift from the ramp surface to the tip side of the cam nose portion 21, and the base circle surface, the ramp surface, and the lift surface are swung. Depending on the swing position of the cam 17, the valve lifter 16 comes into contact with a predetermined position on the upper surface.

  As shown in FIGS. 6 to 9, the transmission mechanism includes a rocker arm 23 disposed above the drive shaft 13, a link arm 24 linking the one end 23 a of the rocker arm 23 and the drive cam 15, and the rocker arm 23. The other end portion 23b of the first and second rocking cams 17 are linked to each other.

  The rocker arm 23 is rotatably supported by a control cam 33 (to be described later) through a support hole at a cylindrical base portion at the center. Further, the one end portion 23a projecting from the outer end portion of the cylindrical base portion is formed with a pin hole through which the pin 26 is inserted, while the other end projecting from the inner end portion of the base portion. The part 23b is formed with a pin hole into which the pin 27 connected to the one end part 25a of the link rod 25 is fitted.

  The link arm 24 includes an annular base 24a having a relatively large diameter and a projecting end 24b projecting at a predetermined position on the outer peripheral surface of the base 24a. The drive cam 15 is located at the center of the base 24a. A fitting hole 24c is formed in which the cam body is rotatably fitted, and a pin hole through which the pin 26 is rotatably inserted is formed in the protruding end 24b.

  The link rod 25 is formed in a substantially square shape having a concave shape on the rocker arm 23 side, and is inserted into each pin hole of the other end portion 23b of the rocker arm 23 and the cam nose portion 21 of the swing cam 17 at both end portions 25a and 25b. Pin insertion holes through which end portions of the pins 27 and 28 are rotatably inserted are formed.

  A snap ring that restricts the movement of the link arm 24 and the link rod 25 in the axial direction is provided at one end of each pin 26, 27, 28.

  The control mechanism 19 is rotatably mounted on the same bearing 14 at a position above the drive shaft 13, and is fixed to the outer periphery of the control shaft 32 and is slidably fitted into a support hole of the rocker arm 23. And a control cam 33 serving as a rocking fulcrum of the rocker arm 23.

  As shown in FIG. 6, the control shaft 32 is arranged in the engine longitudinal direction in parallel with the drive shaft 13, and a journal portion 32b at a predetermined position is formed between the main bracket 14a and the sub bracket 14b of the bearing 14. The bearing is rotatably supported between them.

  The control cam 33 has a cylindrical shape as shown in FIGS. 6 to 9, and the position of the shaft center P <b> 2 is offset from the shaft center P <b> 1 of the control shaft 32 by α.

  As shown in FIGS. 1 to 6, the drive mechanism 6 includes a housing 35 fixed to the rear end portion of the cylinder head 1, and an electric motor 36 that is a rotational force applying mechanism fixed to one end portion of the housing 35. And a ball screw transmission means 37 which is a transmission means provided inside the housing 35 for transmitting the rotational driving force of the electric motor 36 to the control shaft 32.

  As shown in FIG. 1, the housing 35 protrudes upward in the center of the upper end portion of the cylindrical portion 35a disposed substantially along the direction perpendicular to the axial direction of the control shaft 32, and enters the inside. The control shaft 32 includes a bulging portion 35b facing one end portion 32a, and a cylindrical portion 35a and a side wall 35c closing one side portion of the bulging portion 35b. Further, as shown in FIGS. 2 and 5, a substantially rectangular partition wall 70 is erected on the bottom wall of the cylindrical portion 35a, and the partition wall 70 and the bottom wall and side wall 35c of the cylindrical portion 35a. An accommodation chamber 71 for accommodating the ball screw transmission means 37 is formed. As shown in FIGS. 1 and 4, the housing 35 is attached to the rear end portion of the cylinder 1 so as to be inclined downward at a predetermined angle on the right side in the drawing with respect to the horizontal line H.

  Further, the upper end of the partition wall 70 is substantially parallel to the horizontal line H, that is, has an upper right inclination with respect to the housing 35, and as a result, the oil level L is formed along the inclination of the upper end of the partition wall 70.

  The electric motor 36 is constituted by a proportional type DC motor, and a small-diameter portion 38a at the tip end of a substantially cylindrical motor casing 38 is fixed to one end opening 35c of the cylindrical portion 35a by press fitting or the like. Further, the drive shaft 36 a of the electric motor 36 is supported by a ball bearing 39 provided in the tip small diameter portion 38 a of the motor casing 38.

  The electric motor 36 is driven by a control signal from the controller 40 that detects the operating state of the engine. The controller 40 feeds back the detection signals from various sensors such as a crank angle sensor 41, an air flow meter 42, a water temperature sensor 43, and a potentiometer 44 for detecting the rotational position of the control shaft 32, thereby indicating the current engine operating state. A control signal is output to the electric motor 36 as detected by calculation or the like.

  As shown in FIGS. 1 to 6, the ball screw transmission means 37 includes a ball screw shaft 45 disposed substantially coaxially with the drive shaft 36 a of the electric motor 36 in the accommodation chamber 71 of the housing 35, and the ball A ball nut 46 which is a moving member screwed onto the outer periphery of the screw shaft 45, a linkage arm 47 which is a linkage portion formed integrally with one end portion of the control shaft 32 in the housing 35, the linkage arm 47 and the ball The link member 48 is connected mainly to the nut 46, and the link arm 47 and the link member 48 constitute a link mechanism.

  As shown in FIG. 3, the ball screw shaft 45 has a ball circulation groove 49 having a predetermined width continuously formed in a spiral shape on the entire outer peripheral surface excluding both ends, and one end opening portion of the cylindrical portion 35a. Both end portions 45a and 45b respectively facing 35f and the other end opening 35d are rotatably supported by ball bearings 50 and 51.

  A nut 52 for holding the ball screw shaft 45 in the cylindrical portion 35a is screwed to the tip of the other end portion 45b of the ball screw shaft 45. The nut 52 has a protrusion 52a on one end side. The inner ring 51a of the one-side ball bearing 51 is pressed rightward and the stepped surface on the other end 45b side of the ball screw shaft 45 is tightened to the left side. As a result, the inner ring 51a is fixed and the ball screw The shaft 45 rotates together with the shaft 45. The other end opening 35d of the cylindrical portion 35a is screwed with a bowl-shaped cap nut 53. The other end of the outer ring 51b of the one-side ball bearing 51 is opened at the other end by a cylindrical front end portion of the cap nut 53. It is pressed and fixed to the stepped portion 35e of the portion 35d.

  Note that, on the other end portion 45b side of the ball screw shaft 45, when the nut 52 is tightened with a predetermined jig such as a spanner, a two-face width with which the holding jig is engaged so that the ball screw shaft 45 does not rotate. The engaging surfaces 45d and 45d are formed.

  Further, the ball screw shaft 45 is serrated and connected to a small-diameter shaft 45c at one end 45a and a small-diameter portion 36b of the drive shaft 36a of the electric motor 36 so as to be axially movable in a coaxial manner by a cylindrical connecting member 54. .

  That is, serration irregularities are formed along the axial direction on the outer peripheral surfaces of the tip small diameter shaft 45c and the tip small diameter portion 36b, while the serration irregularities are fitted on the inner peripheral surface of the connecting member 54 in a loosely fitted state. A serration portion is formed along the axial direction. The serration coupling transmits the rotational driving force of the electric motor 36 to the ball screw shaft 45 and allows the ball screw shaft 45 to move slightly in the axial direction. Yes.

  As shown in FIGS. 3 and 5, the ball nut 46 is formed in a substantially cylindrical shape, and a guide groove 55 that holds a plurality of balls 64 rotatably on the inner peripheral surface in cooperation with the ball circulation groove 49. Are formed continuously in a spiral shape, and two deflectors 65 for setting the circulation row of the plurality of balls 64 at two positions in the axial direction of the ball nut 46 are attached. That is, the deflector 65 causes the balls 64 to return back into the circulation row in order to circulate the plurality of balls 64 rolling between the ball circulation groove 49 and the guide groove 55 in the same groove. The circulation train is provided at two places in the front and rear in the axial direction. The ball nut 46 is applied with a moving force in the axial direction through the balls 64 while converting the rotational motion of the ball screw shaft 45 into linear motion on the ball nut 46.

  In addition, two pin holes 56 are formed between the circulation rows of the ball nuts 46 substantially along the radial direction. That is, both the pin holes 56 and 56 are formed so as to face each other in the radial direction from the substantially central position in the axial direction of the outer peripheral surface of the ball nut 46 toward the inner peripheral surface, and each of the bottom surfaces 56a and 56a is formed as a ball. A hole having a predetermined thickness t is formed without penetrating from the inner peripheral surface of the nut 46.

  As shown in FIGS. 1 to 5, the linkage arm 47 is formed in a substantially raindrop shape, and a large-diameter base portion is integrally formed with the control shaft 32 via one end portion 32 a of the control shaft 32 and is tapered. A slit 57 is formed at the center of the front end portion 47b in the width direction, and the front end portion 47b is formed with two pin holes 47c and 47c continuously penetrating along the control shaft 32 direction. Yes. Therefore, the axis Z of the pin holes 47c and 47 is offset from the axis P1 of the control shaft 32.

  The link member 48 is formed in a substantially Y shape and includes a flat plate-like one end portion 58 and bifurcated other end portions 59 and 59, and the one end portion 58 is inserted into the slit 57 of the linkage arm 47. The pin holes 47c, 47c and the pin 60 penetrating through the pin holes 58a are rotatably connected to the distal end portion 47b of the linkage arm 47. Note that both ends of the pin 60 are fixed to both pin holes 47 c and 47 c of the linkage arm 47, and the center part is slidable into the pin hole 58 a of the link member 48.

  On the other hand, the bifurcated other end portions 59 and 59 are arranged on both sides of the ball nut 46, and pin holes 59a and 59a formed so as to be opposed to and corresponding to the pin holes 56 and 56 of the ball nut 46, respectively. Is formed so as to penetrate through and are rotatably connected to the ball nut 46 by two pin shafts 61 and 61 inserted into the pin holes 59a and 59a and the pin holes 56 and 56 of the ball nut 46, respectively. . In other words, the outer ends of the pin shafts 61 and 61 are fixed to the pin holes 59a and 59a, respectively, and the inner ends rotate to the pin holes 56 and 56 through a minute gap C. It is inserted freely.

  An oil gallery 34 is formed in the control shaft 32 along the axial center direction, and the lubricating oil O in the cylinder head 1 is guided into the oil gallery 34 in the radial direction of the journal portion 32b. An oil introduction hole 34a is formed through. On the other hand, an oil outlet hole 34b for supplying the lubricating oil O in the oil gallery 34 to the link member 48 side through the distal end portion 47b is formed in the large-diameter base portion of the linkage arm 47 along the radial direction. The lubricating oil O that has flowed out of the oil outlet hole 34b travels along the outer surface of the link member 48 as shown by the broken line arrows in FIGS. And the guide groove 55 are supplied to the interior of the storage chamber 71 directly from the outer surface of the link member 48. Accordingly, in the storage chamber 71, almost the entire ball screw transmission means 37 is immersed in the lubricating oil O that is filled up to the height h (liquid level L) of the partition wall 70. Further, the lubricating oil O that has filled the storage chamber 71 and has become more than the partition wall 70 overflows as it is from the upper end of the partition wall 70 and is discharged onto the cylinder head 1, and eventually circulates in the storage chamber 71. It has become.

  Since the housing 35 is disposed in an upwardly inclined manner with respect to the cap nut 53 side as viewed in the horizontal direction, the liquid level L of the lubricating oil O is inclined with respect to the direction of the cylindrical portion 34, and the ball nut 4 is substantially immersed in the lubricating oil O at the right position (small valve lift area) shown in FIG. 4, and the ball nut 46 is at the left position (high valve lift area) shown in FIG. A part of the oil is not covered with the lubricating oil O.

  A drain plug 72 for properly discharging the lubricating oil O in the storage chamber 71 is detachably provided on the bottom wall of the cylindrical portion 35a on the storage chamber 71 side.

  As shown in FIG. 2, the bearing 14 is provided with two first and second stopper pins 62 and 63 that are regulating mechanisms that regulate the left and right maximum rotational positions of the control shaft 32 via the linkage arm 47. ing.

  That is, the first stopper pin 62 rotates the control shaft 32 counterclockwise in FIG. 1 to reduce the valve lift amount of the intake valves 2 and 2 by the variable mechanism 4 as shown in FIG. It is fixed at the position. On the other hand, the second stopper pin 63 is fixed at the side wall 35c position where the control shaft 32 rotates clockwise as shown in FIG. The minimum and maximum rotational positions of the left and right sides of the control shaft 32 are regulated by the pins 62 and 63.

  Hereinafter, the operation of the present embodiment will be described. First, for example, in the low rotation operation region including the idling operation of the engine, the rotational torque transmitted to the electric motor 36 by the control signal from the controller 40 is the ball screw. When the rotation is transmitted to the shaft 45, each ball 64 rolls between the ball circulation groove 49 and the guide groove 55 with this rotation, and the ball nut 46 is moved to the maximum rightward position as shown in FIG. Move in a straight line.

  As a result, the control shaft 32 is rotationally driven counterclockwise by the link member 48 and the linkage arm 47, and the side surface of the distal end portion 47 b of the linkage arm 47 abuts on the first stopper pin 62 and further rotation is restricted. The

  Therefore, in the control cam 33, the shaft center P2 rotates around the shaft center P1 of the control shaft 32 with the same radius as shown in FIGS. 7A and 7B, and the thick portion moves away from the drive shaft 13 upward. . As a result, the other fulcrum 23b of the rocker arm 23 and the pivot point of the link rod 25 move upward with respect to the drive shaft 13, so that each swing cam 17 is connected to the cam nose portion 21 via the link rod 25. The side is forcibly pulled up and the whole is rotated clockwise.

  Therefore, when the drive cam 15 rotates and pushes up the one end portion 23a of the rocker arm 23 via the link arm 24, the valve lift amount is transmitted to the swing cam 17 and the valve lifter 16 via the link rod 25. The lift amount L1 is sufficiently small.

  Therefore, in the low rotation region of such an engine, the valve lift amount becomes the smallest, so that the opening timing of each intake valve 2 is delayed, and the valve overlap with the exhaust valve is reduced. For this reason, improvement in fuel consumption and stable rotation of the engine can be obtained.

  Further, the positive / negative (+, −) alternating torque acting on the control shaft 32 at this time is sufficiently small as indicated by T 1 ′ in FIG. 10, and is therefore transmitted to the ball nut 46 via the linkage arm 47 and the link member 48. Since the applied load is small, no large concentrated load is generated on the threaded portions of the ball screw shaft 45 and the ball nut 46.

  Therefore, the occurrence of wear or the like between the ball screw shaft 45 and the ball nut 46 due to the ball 64 is prevented.

  In addition, when the engine is shifted to the middle engine rotation region, the electric motor 36 is rotated in reverse by a control signal from the controller 40. When this rotation torque is transmitted to the ball screw shaft 45 and rotated, the ball nut 46 is accompanied with this rotation. Moves linearly from the position shown in FIG. Therefore, the control shaft 32 rotates the control cam 33 clockwise from the position shown in FIG. 7 to rotate the shaft center P2 slightly downward as shown in FIGS. 8A and 8B. For this reason, the entire rocker arm 23 moves toward the drive shaft 13 this time, and the other end 23b presses the cam nose portion 21 of the swing cam 17 downward via the link rod 25 so that the swing cam 17 The whole is rotated counterclockwise by a predetermined amount.

  Therefore, when the drive cam 15 rotates and pushes up the one end portion 23a of the rocker arm 23 via the link arm 24, the valve lift amount is transmitted to the swing cam 17 and the valve lifter 16 via the link rod 25. The lift amount L2 is slightly increased.

  Further, the positive and negative (+, −) alternating torque at this time is relatively larger than that at the time of the minimum lift as shown by T2 ′ in FIG. 10, but between the ball screw shaft 45 and the link member 48. Since the angle θ formed is smaller than that during the minimum lift, the radial load between the ball nut 46 and the ball screw shaft 45 is suppressed, and the generation of a large concentrated load can be avoided.

  Further, when the engine has shifted to the high engine speed region, when the electric motor 36 is further reversely rotated by the control signal from the controller 40 and the ball screw shaft 45 is further rotated in the same direction, the ball nut 46 is moved along with this rotation. As shown in FIG. 1, the ball 64 moves greatly to the left as shown in FIG. 1, but at this time, the further movement is restricted at the position where the linkage arm 47 hits the second stopper pin 63, and the ball nut 46 exceeds that. Movement is also restricted. Therefore, the control shaft 32 rotates the control cam 33 in the clockwise direction from the position shown in FIG. 8, and the shaft center P2 moves downward as shown in FIGS. 9A and 9B. For this reason, the entire rocker arm 23 is moved in the direction of the drive shaft 13 and the cam nose portion 21 of the swing cam 17 is pressed downward via the link rod 25 by the other end portion 23b. Is rotated counterclockwise by a predetermined amount.

  Therefore, the contact position of the cam surface 22 with respect to the upper surface of the valve lifter 16 of the swing cam 17 moves to the left position (lift side). For this reason, when the drive cam 15 rotates and the one end 23a of the rocker arm 23 is pushed up via the link arm 24 when the intake valve 12 is opened, the lift amount L3 with respect to the valve lifter 16 is larger than the intermediate valve lift amount L2. Become.

  Therefore, in such a high rotation region, the valve lift amount is maximized, the opening timing of each intake valve 2 is advanced, and the closing timing is delayed. As a result, the intake charging efficiency is improved and a sufficient output can be secured.

  Then, the positive / negative (+, −) alternating torque at this time becomes larger than that during the middle valve lift as indicated by T3 ′ in FIG. However, since the angle θ2 formed between the ball screw shaft 45 and the link member 48 is smaller than that in the middle lift as well as in the minimum lift, the radial load F3r is sufficiently suppressed. A large alternating load transmitted from the control shaft 32 via the linkage arm 47 and the link member 48 is applied to the circumferential direction of the guide groove 55 of the ball nut 46 and the ball circulation groove 49 of the ball screw shaft 45 via each ball 64. Since it is received in the entire region, the input load is distributed in the circumferential direction, and the generation of concentrated load can be sufficiently avoided.

  Therefore, the occurrence of wear or the like between the guide groove 55 and the ball circulation groove 49 can be effectively prevented, so that the durability of the apparatus can be improved.

  In particular, the component force in the axial direction is received by the entire ball circulation groove 49 and the guide groove 55 not by one row but by two right and left circulation rows, so that the component force is dispersed in a larger range. Occurrence can be further prevented.

  In addition, as described above, the rotational force of the ball screw shaft 45 is transmitted to the ball nut 46 by rolling the balls 64 in a rolling contact state between the ball circulation groove 49 and the guide groove 55. Since the frictional resistance between the respective parts becomes extremely small, the movement of the ball nut 46 becomes smooth and the movement responsiveness is improved. As a result, the valve lift control responsiveness of the intake valves 2 and 2 by the control shaft 32 is also improved in accordance with changes in the engine operating state.

  Further, since the ball screw shaft 45, the ball nut 46, the linkage arm 47, the link member 48, and the like of the ball screw transmission means 37 are immersed in the lubricating oil O in the housing chamber 71, the lubricating oil O is interposed between the components. Is sufficiently supplied, the rattling noise between the components due to the alternating torque transmitted from the intake valves 2 and 2 via the control shaft 32 is effectively suppressed by the viscous resistance of the lubricating oil O. In addition, it is possible to prevent the occurrence of wear between the components by improving the lubrication performance.

  In particular, the lubricating oil O is not simply supplied to the ball screw transmission means 37, but the ball screw transmission means 37 is immersed, so that the viscous resistance effect can be sufficiently exhibited. it can.

  Further, the lubricating oil O is constantly supplied from the oil gallery 34 into the housing chamber 71 or circulates around the ball screw transmission means 37 in combination with the lubricating oil stirring effect accompanying the movement of the ball nut 46. Therefore, the deterioration of the lubricating oil O in the storage chamber 71 can be prevented, and each component of the ball screw transmission means 37 can be effectively cooled.

  Further, since the ball nut 46 is free to be freely rotated by the bifurcated other end portions 59 and 59 of the link member 48 and the pin shafts 61 and 61, the rotational force of the ball screw shaft 45 is efficiently transmitted. can do.

  In addition, as described above, the lubricating oil O led to the outside from the oil gallery 34 of the control shaft 32 through the oil lead-out hole 34b is formed on the link member 48 as shown by the broken-line arrows in FIGS. Along the outer surface, it goes around each inner surface of the bifurcated other end portion 59, 59, enters into the minute gap portions C, C, and lubricates between the inner ends of the pin shafts 61, 61. Therefore, the lubrication performance for the connecting portion between the ball nut 46 and the link member 48 is improved.

  Further, the height of the oil surface L is such that a large amount of the lubricating oil O is applied to the ball screw transmission means 37 in the housing chamber 71 during the small valve lift control, which is a normal area of the vehicle, depending on the inclination angle of the housing 35. Since the direction is long, the viscous resistance caused by the lubricating oil O can effectively suppress the generation of operating noise of each component of the ball screw transmission means 37 that increases in the normal range. Generation of wear can be suppressed.

  On the other hand, during the high valve lift control, the lubricating oil O is smaller than that during the small valve lift, so that the viscous resistance of the lubricating oil O is reduced, thereby improving the operation response of the ball nut 46 to the ball screw shaft 45. . Therefore, the acceleration performance of the vehicle is improved.

  Furthermore, the so-called astringent phenomenon with the ball screw shaft 45 when the ball nut 46 is moved in the high valve lift direction can also be avoided by the lubricating oil O. That is, when the ball screw shaft 45 rotates and the ball nut 46 moves to the left as shown in FIG. 1, the further movement is restricted at the position where the linkage arm 47 hits the second stopper pin 63. Further movement of the ball 46 is also restricted, but here, since the ball screw shaft 45 rotates vigorously with inertia, each ball 64 is moved by each tooth side surface of each ball circulation groove 49 in FIG. Push out to the left. For this reason, each ball 64 tends to ride on a mountain portion between the guide grooves 55 of the ball nut 46. As a result, each ball 64 is strongly pressed by the reaction force between the tooth side surface of the ball screw shaft 45 and the tooth side surface of the ball nut 46, thereby causing an astringent phenomenon. In particular, when the lead angles of the ball circulation groove 49 and the guide groove 55 are small, a so-called wedge effect also works and a greater astringency phenomenon occurs.

  However, in this embodiment, since the ball screw shaft 45 and the ball nut 46 are always immersed in the lubricating oil O, and the lubricity is extremely good, the transition to the high valve lift is performed for a moment. Even in this case, good lubricity is maintained and the astringency phenomenon can be effectively avoided. Therefore, the switching movement of the ball nut 46 can be performed smoothly. At this time, the oil surface is agitated as the ball nut 46 moves, and the lubricity of each part is further improved and the circulation of the lubricating oil is also improved.

  The present invention is not limited to the configuration of the above-described embodiment. For example, the arrangement of the electric motor 36 can be freely changed depending on the layout of the engine room, and may be on the opposite left side instead of the right side shown in FIG. Further, the rotation imparting mechanism may be a hydraulic motor in addition to the electric motor. Further, the present invention can be applied to the exhaust valve side or both valve sides in addition to the intake valve side.

  Furthermore, although a deflector is shown as an example of forming a circulation row of ball screws, a method of forming a circulation row using a tube or the like may be used.

  Further, the transmission means is not limited to the ball type of the ball screw transmission means 37, and is constituted by a screw shaft having a male screw cut on the outer peripheral surface and a moving member having a female screw cut on the inner peripheral surface. It is also possible.

The technical ideas other than the claims that can be grasped from the respective embodiments will be described below.
(B) The actuator device according to claim 1, wherein the transmission means is accommodated in an accommodation chamber in a housing filled with lubricating oil.
(B) The variable mechanism of the variable valve device rotates in synchronization with the crankshaft of the engine, and is supported by a drive shaft provided with a drive cam on the outer periphery and a support shaft so as to be swingable. A swing cam that opens and closes the engine valve by slidingly contacting the upper surface of the valve lifter, and a rocker arm that has one end mechanically linked to the drive cam and the other end linked to the swing cam via a link rod. ,
By changing the rocking fulcrum of the rocker arm according to the engine operating state, the contact position of the cam surface of the rocking cam with the upper surface of the valve lifter is changed to make the valve lift of the engine valve variable. The actuator device according to claim 1.
(C) The screw shaft has a ball circulation groove in the circumferential direction of the outer peripheral surface, while the moving member is capable of rolling a plurality of balls in cooperation with the ball circulation groove in the circumferential direction of the inner peripheral surface. The link mechanism has a guide groove to be held and linearly moves in the axial direction of the screw shaft through the plurality of balls as the screw shaft rotates, and the link mechanism includes a linkage arm having one end connected to the control shaft. And a link member pivotally linked to the moving member and the other end pivotally linked to the other end of the linkage arm. Actuator device.
(D) The actuator according to claim 1, wherein the transmission means is lubricated by a larger amount of lubricating oil at the time of small valve lift control than at the time of high valve lift control of the engine valve by a variable mechanism. apparatus.

  According to the present invention, it is possible to effectively suppress the generation of operating noise of the transmission means that increases in the normal range due to the viscous resistance caused by a large amount of lubricating oil during the small valve lift that is the normal range of the vehicle. The occurrence of wear due to oil can be suppressed.

On the other hand, during the high valve lift control, the lubricating oil is smaller than that during the small valve lift, so that the viscous resistance of the lubricating oil is reduced, thereby improving the operation responsiveness of the transmission means. Therefore, the acceleration performance of the vehicle is improved.
(E) The actuator device according to claim 1, further comprising a drain plug capable of discharging the lubricating oil.

  According to the present invention, when the lubricating oil of the engine is replaced, the lubricating oil in the storage chamber can be easily replaced by the drain plug, and only the storage chamber can be replaced independently. The effect can be enhanced.

It is a longitudinal cross-sectional view which shows the drive mechanism of embodiment of this invention. It is the sectional view on the AA line of FIG. It is a principal part longitudinal cross-sectional view of the drive mechanism of this embodiment. It is operation | movement explanatory drawing of the drive mechanism at the time of the minimum lift control in this embodiment. FIG. 6 is a sectional view taken along line B-B in FIG. 5. It is a perspective view of the variable valve apparatus to which the drive mechanism of this embodiment was applied. 6A is a C arrow view of FIG. 6 showing the valve closing action during the minimum lift control in the variable valve operating apparatus, and B is a C arrow view of FIG. 6 showing the valve opening action during the minimum lift control. FIG. 7A is a C arrow view of FIG. 6 showing the valve closing action during the middle lift control in the variable valve operating apparatus, and B is a C arrow view of FIG. 6 showing the valve opening action during the middle lift control. 6A is a C arrow view of FIG. 6 showing the valve closing action during the maximum lift control in the variable valve operating apparatus, and B is a C arrow view of FIG. 6 showing the valve opening action during the maximum lift control. It is a characteristic view which shows the relationship between valve lift amount and alternating torque.

Explanation of symbols

2 ... Intake valve (engine valve)
4 ... Variable mechanism 6 ... Drive mechanism (actuator device)
32 ... Control shaft 36 ... Electric motor (rotational force applying mechanism)
37 ... Ball screw transmission means (screw transmission means)
45 ... Ball screw shaft (screw shaft)
46 ... Ball nut (moving member)
47 ... Linking arm 48 ... Link member 49 ... Ball circulation groove 55 ... Guide groove 70 ... Bulkhead 71 ... Storage chamber O ... Lubricating oil

Claims (4)

A rotational force imparting mechanism that imparts rotational force to a control shaft that variably controls the valve lift amount of the engine valve via the variable mechanism by rotating;
Screw transmitting means for transmitting the rotational force of the rotational force applying mechanism to the control shaft and rotating the control shaft based on the rotational force of the rotational force applying mechanism;
The screw transmission means includes a screw shaft rotatably supported;
A moving member screwed onto the outer periphery of the screw shaft;
A linkage arm integrally formed or connected to the control shaft;
A link member having one end side linked to a position deviated with respect to the axis of the control shaft of the linkage arm and the other end side rotatably connected to the moving member;
An actuator device characterized in that lubricating oil derived from an engine through the control shaft flows through the link member via the linkage arm. The actuator device according to claim 1, wherein the screw shaft is configured by a ball screw shaft, and the moving member is configured by a ball nut. A rotational force imparting mechanism that imparts rotational force to a control shaft that variably controls the valve lift amount of the engine valve via the variable mechanism by rotating;
Screw transmitting means for transmitting the rotational force of the rotational force applying mechanism to the control shaft and rotating the control shaft based on the rotational force of the rotational force applying mechanism;
The screw transmission means includes a screw shaft rotatably supported;
A moving member having two pin holes drilled oppositely and screwed onto the outer periphery of the screw shaft;
A linkage arm integrally formed or connected to the control shaft;
One end side is linked to a position deviated from the axis of the control shaft of the linkage arm, and the other end side is formed in a bifurcated shape. A link member having two pin holes formed therethrough;
Each pin hole of the link member and each pin hole of the moving member, and having two pin shafts rotatably connecting the link member to the moving member,
Lubricating oil derived from the engine through the control shaft is supplied to each gap portion formed between each pin shaft and each pin hole of the moving member while being transmitted through the link member via the linkage arm. An actuator device characterized by being configured as described above. The actuator device according to claim 3, wherein the screw shaft is configured by a ball screw shaft, and the moving member is configured by a ball nut.

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