JP2008303880A - Actuator of variable valve gear - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an actuator capable of preventing the rotating and controlling accuracy of a control shaft from being lowered by suppressing the oscillation of a ball nut by a link member for stabilizing the axial movement of the ball nut. <P>SOLUTION: This actuator comprises a ball nut 46 linearly moved in the axial direction via a plurality of balls 54 with the rotation of a ball screw shaft 45 by the rotating drive of an electric motor and a link arm 47 and a link member 48 for linking the ball nut to the control shaft 32. The link member comprises link parts 48a, 48a arranged parallel to each other at a predetermined gap and a connection part 48b for connecting the link parts to each other. The oscillation of the ball nut is restrained by holding both sides of the pivotally supporting part 55 of the ball nut 46 and both sides of the end part 47b of the link arm 47 by the fork-shaped both end parts formed by the both link parts. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an actuator for a variable valve operating apparatus that variably controls, for example, a valve lift amount and an operating angle of an intake valve and an exhaust valve of an internal combustion engine according to an engine operating state.

  Various actuators of a variable valve operating apparatus in a conventional internal combustion engine are provided, and one of them is described in Patent Document 1 below, for example.

  In brief, this actuator can move in the axial direction by screwing the screw shaft, which is controlled forward and backward by an electric motor, and the male screw formed on the outer peripheral surface of the screw shaft with the inner peripheral female screw. A movable nut, a link member whose bifurcated one end is pivotably linked to both sides of the movable nut via a pin, one end is linked to the other end of the link member, and the other end is controlled And a lever member rotatably linked to the shaft via a pin, and an adjustment cam is fixed to the control shaft.

Then, when the screw shaft rotates forward and backward in accordance with forward / reverse rotation driving of the electric motor, the moving nut moves in the axial direction, and the rotational position of the control shaft is controlled via the link member and the lever member. It is like that.
US Pat. No. 6,615,777

  However, in this conventional variable valve operating device, the link member has a bifurcated one end portion pivotally supported by pins on both sides of the moving nut, but the other end portion is formed as a single piece. The pin is disposed in a notch groove formed at the center of the tip of the linkage arm and pivotally supported by a pin. For this reason, there exists a possibility that a link member may tilt by the rocking | fluctuation force of the rotation direction which the said movement nut receives from a screw shaft.

  That is, the moving nut is caused to rotate by the frictional resistance between the female and male screws due to the forward / reverse rotational force of the screw shaft, and slightly swings in the forward / reverse direction. For this reason, this swinging force is transmitted from one end of the link member to the other end, and the entire link member is rattled from side to side. This is because the other end portion of the link member is formed as a single piece and is accommodated in the notch groove of the linkage arm, so that there is no play through the gap between the other end portion and the notch groove. Will occur.

  As a result, the movement of the moving nut in the axial direction becomes unstable, and the accuracy of rotation transmission to the control shaft may be reduced.

The present invention has been devised in view of the actual state of the conventional actuator. In the invention according to claim 1, the rotational position of the control shaft is controlled by controlling the rotational position of the control shaft according to the engine operating state. An actuator of a variable valve operating device that changes an operating state,
A linkage arm fixed to the control shaft and rotating integrally with the control shaft; a rotation imparting mechanism for rotating and controlling an output shaft having a threaded portion formed on an outer periphery thereof according to an operating state of the engine; and the output A moving nut provided on the outer periphery of the shaft and moving in the axial direction through the threaded portion as the output shaft rotates, and is slidably connected between the linkage arm and the moving nut to move the moving A link member that converts the axial movement of the nut into a rotational motion and transmits it to the control shaft, and a screw transmission mechanism that includes at least the output shaft, the moving nut, the linkage arm, and the link member are housed in the interior. And a housing supplied with lubricating oil,
The link member is connected by connecting a pair of substantially parallel plate-like link portions having both ends in a bifurcated shape, and opposite edges excluding the both ends so that both ends of the link portions are open. And the cross section is formed in a substantially U shape by the part,
The pair of link portions sandwich both ends of the linkage arm and both sides of the pivot portion formed on the moving nut.

  According to the present invention, since the bifurcated portions on both end sides of the link member are sandwiched from both sides of the distal end portion of the linkage arm and both pivot support portions of the moving nut, the other end portion is a single piece as in the prior art. Compared to the case, the link width between the linkage arm and the other end of the link member can be made sufficiently large, so that the tilting of the link member due to the swinging force of the moving nut can be restricted.

  As a result, since the swing of the moving nut can be suppressed, the movement in the axial direction can be stabilized, and the rotation control accuracy of the control shaft can be prevented from being lowered.

  Further, since the linkage arm is fixed to the control shaft and swings integrally, there is no tilting of the linkage arm, so that the tilting of the link member due to the swinging force of the moving nut can be prevented more reliably.

  A screw transmission mechanism including at least the output shaft, a moving nut, a linkage arm, and a link member is housed in a housing supplied with lubricating oil, and the link member is formed in a bifurcated shape at both ends. A substantially parallel plate-shaped pair of link portions and a connecting portion that connects opposite end edges of the two link portions to form a substantially U-shaped cross section, and is disposed above the moving nut in the gravitational direction, The opening located on the opposite side to the connecting portion is arranged above the gravity direction.

  According to the present invention, the lubricating oil inside the housing is splashed or atomized by the operation of the screw transmission mechanism, and flows down from the opening of the link member to the upper surface of the connecting portion, the inner surface of each link portion, or the like. Thus, the lubricating oil is supplied around the pivotal support portion of the moving nut and between the meshing portions with the screw shaft. Therefore, the lubricating performance of these members is improved.

  Further, it is desirable that the bifurcated end portion of the link member on the moving nut side is formed to open toward the side end portion of the pivot portion formed at one axial end portion of the moving nut.

  According to this invention, since the lubricating oil adhering to the connecting portion and each link member from the opening portion of the link member described above is opened with each link portion being bifurcated, the lubricating oil is removed from the moving nut. It can be directly supplied to both sides of the pivotal support part and the meshing part of the moving nut and the screw shaft. Therefore, the lubricating performance of the meshing portion between the moving nut and the screw shaft is further improved.

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

  That is, as shown in FIGS. 7 to 12, the variable valve operating device is slidably provided on the cylinder head 1 via a valve guide (not shown) 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 And a drive mechanism 6 which is an actuator for rotationally driving.

  The variable mechanism 4 includes a hollow drive shaft 13 rotatably supported by a bearing 14 provided on the upper portion of the cylinder head 1, and a drive cam 15 which is an eccentric rotary cam fixed to the drive shaft 13 by press-fitting or the like. And is pivotally supported on the outer peripheral surface of the drive shaft 13 and slidably contacts the upper surfaces of the valve lifters 16, 16 disposed at the upper ends of the intake valves 2, 2 to open the intake valves 2, 2. Transmission that transmits the rotational force of the drive cam 15 as the swinging force of the swing cams 17, 17 linked to the two swing cams 17, 17 to be operated, and the drive cam 15 and the swing cams 17, 17. Means.

  As shown in FIG. 9, 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. 11A, 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 provided at the upper end portion of the main bracket 14a to be described later. The brackets 14a and 14b are rotatably fastened together by a pair of bolts 14c and 14c.

  As shown in FIG. 10, the drive cam 15 has a substantially ring shape, and is composed of an annular cam main body and a cylindrical portion integrally provided on the outer end surface of the cam main body. A drive shaft insertion hole is formed therethrough, and the axis Y of the cam body is offset from the axis X of the drive shaft 13 by a predetermined amount in the radial direction. 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 two swing cams 17 have substantially the same raindrop shape, and are integrally provided at both ends of the annular camshaft 20, and the camshaft 20 is connected to the drive shaft 13 via the inner peripheral surface. Is supported rotatably. In addition, a pin hole is formed through the tip portion on 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.

  The transmission means 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, the other end 23 b of the rocker arm 23, and the swing cam 17. And a link rod 25 that cooperates with 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 protruding from the outer end portion of the cylindrical base portion has a pin hole through which the pin 26 is fitted, while the other end portion protruding from the inner end portion of the base portion. 23b has a pin hole into which a pin 27 connected to one end of the link rod 25 is inserted.

  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. 7, the control shaft 32 is arranged in the engine longitudinal direction in parallel with the drive shaft 13, and the journal portion at a predetermined position is formed between the main bracket 14a of the bearing 14 and the sub bracket 14b. The bearing is rotatably supported between them.
In addition, an oil passage 32 b that forms part of a hydraulic circuit that supplies lubricating oil into the drive mechanism 6 is formed in the direction of the internal axis of the control shaft 32.

  The control cam 33 has a cylindrical shape, and the position of the axis P2 is deviated from the axis P1 of the control shaft 32 by a predetermined amount.

  As shown in FIGS. 5 to 7, 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 mechanism 37 that is provided inside the housing 35 and transmits the rotational driving force of the electric motor 36 to the control shaft 32.

  As shown in FIGS. 5 and 6, the housing 35 is integrally formed of an aluminum alloy material or the like, and is disposed inside the housing 35 along a direction substantially perpendicular to the axial direction of the control shaft 32. Is formed in the middle of the upper end portion of the housing portion 35a, and a bulging chamber 35b is formed in the interior of which the one end portion 32a of the control shaft 32 faces. , 35b constitute a working chamber.

  Further, the front chambers of both the storage chambers 35a and 35b are closed by a cover (not shown) through a seal member.

  Further, the storage chamber 35a is formed with a circular opening 35c at one end in the axial direction, and the other end is closed by a wall 35d. In addition, lubricating oil O having a maximum level L at a position directly below the ball screw transmission mechanism 37 is supplied into the storage chamber 35a.

  The electric motor 36 is constituted by a proportional type DC motor, and is fixed in a state where a tip end portion 38a of a substantially cylindrical motor casing 38 seals one end opening 35c of the storage chamber 35a. The electric motor 36 is sealed via a drive shaft 36a by a mechanical seal 39a provided on the inner peripheral side of a cylindrical retainer 39 press-fitted into the inner peripheral surface of the one end opening 35c. Further, as shown in FIG. 7, the electric motor 36 is driven by a control signal from a control unit 40 that detects the operating state of the engine.

  The control unit 40 feeds back 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 to detect the rotational position of the control shaft 32, and feeds back the current engine. An operation state is detected by calculation or the like, and a control signal is output to the electric motor 36.

  The ball screw transmission mechanism 37 includes a ball screw shaft 45 disposed substantially coaxially with the drive shaft 36a of the electric motor 36 in the housing chamber 35a of the housing 35, and a movement screwed to the outer periphery of the ball screw shaft 45. A ball nut 46 that is a nut, a linkage arm 47 that is axially connected to one end 32a of the control shaft 32 in the bulging chamber 35b, and a link member 48 that links the linkage arm 47 and the ball nut 46. The linkage arm 47 and the link member 48 constitute a transmission mechanism.

  In the ball screw shaft 45, a ball circulation groove 49, which is a screw portion having a predetermined width, is continuously formed in a spiral shape on the entire outer peripheral surface excluding both ends, and one end opening 35c and the other end of the storage chamber 35a. Both end portions 45a and 45b respectively facing the small-diameter portion of the portion are rotatably supported by ball bearings 50 and 51. The one ball bearing 50 is press-fitted and fixed inside the one end opening 35c, and the other ball bearing 51 is press-fitted and fixed inside the small diameter portion of the other end.

  Further, the ball screw shaft 45 has a hexagonal shaft at the tip of one end 45a and a tip of the drive shaft 36a of the electric motor 36 coupled to each other by a cylindrical connecting member 52 so as to be axially movable. The rotational driving force of the motor 36 is transmitted to the ball screw shaft 45 and a slight movement of the ball screw shaft 45 in the axial direction is allowed.

  The ball nut 46 is formed in a substantially cylindrical shape, and a guide groove 53 for continuously holding a plurality of balls 54 so as to be able to roll together with the ball circulation groove 49 is continuously formed in a spiral shape on the inner peripheral surface. At the same time, two deflectors for setting the circulation row of the plurality of balls 54 at the two front and rear positions in the axial direction of the ball nut 46 are attached. In other words, this deflector guides the balls 54 so as to return again into the same circulation row in order to circulate the plurality of balls 54 rolling between the ball circulation grooves 49 and the guide grooves 53 in the same grooves. This circulation train is provided at two positions 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 54 while converting the rotational motion of the ball screw shaft 45 into linear motion on the ball nut 46.

  Further, as shown in FIGS. 1 and 5 to 7, the ball nut 46 has a pivotal support portion 55 rotatably connected to the other end portion of the link member 48 at the outer end portion on the control shaft 32 side. A pair of left and right cutout grooves 56 that allow the link member 48 to tilt and swing are formed near the lower portion of the pivotal support portion 55.

  The pivot portion 55 is integrally formed in a substantially cylindrical shape at the end of the ball nut 46 on the side of the electric motor 36 in the axial direction. A pivot pin 57 is fixed therethrough, and the upper end portion is a ball nut. It protrudes slightly from the upper outer surface of 46.

  On the other hand, the notch groove 56 is formed by cutting out the upper end portion of the ball nut 46 from the base end side of the pivotal support portion 55 into a substantially half-U shape, and a gap C between the other end portion outer peripheral surface of the link member 48. Is formed.

  As shown in FIGS. 1 and 5 to 7, the linkage arm 47 is formed in a substantially raindrop shape, and a large-diameter base 47 a is integrally fixed to one end 32 a of the control shaft 32 from the axial direction. A pin hole 47c that penetrates continuously along the direction of the control shaft 32 is formed through the tapered tip 47b. In addition, an oil hole 47d constituting a part of a hydraulic circuit communicating with one end portion of the oil passage 32b in the control shaft 32 from the radial direction is continuously formed in the large-diameter base portion 47a and the tip portion 47b. ing. The oil hole 47d has an end on the tip 47b side that opens into the pin hole 47c, and supplies lubricating oil into the storage chamber 35a through the pin hole 47c.

  The lubricating oil in the storage chamber 35a is supplied from the oil passage 32b and the oil hole 47d, but is appropriately discharged to the outside through a drain hole (not shown) formed at a predetermined position on the bottom of the housing 35. As described above, a constant oil level L is maintained.

  As shown in FIGS. 1 to 4, the link member 48 is formed by bending a plate material into a substantially U-shaped cross section by press molding, and a pair of parallel and long flat plate link portions 48a and 48a. The link portions 48a and 48a are connected to each other at a substantially central position. Therefore, both end portions of the link member 48 are formed with an opening portion 48c (predetermined gap) elongated on the opposite side to the connecting portion 48b by both link portions 48a, 48a, and both end portions are also in such an open state, that is, parallel. It has a bifurcated shape.

  In addition, the link member 48 is fitted at one end thereof so that the link 47a and 48a sandwich the arm portion 47a of the linkage arm 47 from both sides with a slight clearance. The pin holes 48d and 48d and a pin hole 47c on the tip side of the arm portion 47a are respectively connected to the tip portion of the arm portion 47b through a pin 59 so as to be swingable. On the other hand, the other end portion is fitted so that the pivot portion 55 is sandwiched between the link portions 48a and 48a with a slight clearance, and the pin holes 48e and 48e formed therein and the pivot portion 55 are respectively formed. The pin 57 is inserted into the pin hole 55 a and is rotatably connected to the pivotal support portion 55.

  Note that both ends of the pins 57 and 59 are fixed to the pin holes 48d, 48d, 48e and 48e by caulking.

  Therefore, as shown in FIG. 6, the link member 48 can tilt and swing substantially along the axis of the ball screw shaft 45 and substantially along the outer surface axial direction of the ball nut 46 via the pivot portion 55. In the fully tilted posture, the upper end portion slightly protrudes upward from the outer surface of the ball nut 46.

  The potentiometer 44 is a general one, and is arranged in front of the linkage arm 47, and a detection pin (not shown) rotates along with the rotation of the linkage arm 47 that rotates in synchronization with the control shaft 32. The position is detected by the sensor unit 44a, and this detection signal is output to the control unit 40.

  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 control unit 40 is When the rotation is transmitted to the screw shaft 45, each ball 54 rolls between the ball circulation groove 49 and the guide groove 53 along with this rotation, and the ball nut 46 is moved in the maximum left direction as shown in FIG. Move to a straight line.

  As a result, the control shaft 32 is rotationally driven clockwise by the link member 48 and the linkage arm 47 as shown in FIG.

  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. 11A and 11B, 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 becomes sufficiently small.

  Therefore, in the low speed region of such an engine, the valve lift amount L1 becomes the smallest in FIG. 13, 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 and negative alternating torque acting on the control shaft 32 at this time is sufficiently small, and therefore the load transmitted to the ball nut 46 via the linkage arm 47 and the link member 48 is also small, so that the ball screw shaft 45 and the ball There is no generation of a large concentrated load on the threaded portion of the nut 46. Therefore, the occurrence of wear or the like between the ball screw shaft 45 and the ball nut 46 due to each ball 54 is prevented.

  In addition, when the engine has shifted to the high engine speed region, the electric motor 36 is rotated in reverse by a control signal from the control unit 40. When this rotational torque is transmitted to the ball screw shaft 45 and rotated, 46 linearly moves from the position shown in FIG. 5 to the right shown in FIG.

  Therefore, the control shaft 32 rotates the control cam 33 in the clockwise direction from the position shown in FIG. 11 to rotate the shaft center P2 downward as shown in FIGS. 12A and 12B. 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 increases.

  Therefore, in such a high rotation region, the valve lift amount L2 of each intake valve 2 is maximized as shown in FIG. 13, and 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.

  And the positive / negative alternating torque at this time becomes larger than the case of the minimum lift. However, since the angle formed between the ball screw shaft 45 and the link member 48 is smaller than that during the minimum lift, the radial load is sufficiently suppressed, and as described above, the linkage arm 47 and the link member 48 from the control shaft 32. Since the large alternating load transmitted through the ball 54 is received in the entire circumferential direction of the guide groove 53 of the ball nut 46 and the ball circulation groove 49 of the ball screw shaft 45 through each ball 54, the input load is applied. Are distributed in the circumferential direction, and the generation of concentrated load can be sufficiently avoided.

  Therefore, since the occurrence of wear and the like between the guide groove 53 and the ball circulation groove 49 can be effectively prevented, the durability of the apparatus can be improved.

  Moreover, as described above, the rotational force of the ball screw shaft 45 is transmitted to the ball nut 46 by rolling the balls 54 between the ball circulation groove 49 and the guide groove 53 in a substantially rolling contact state. 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.

  In addition, according to this embodiment, since both ends of the linkage arm tip portion 47b and both sides of the pivot portion 55 of the ball nut 46 are sandwiched by one end portions of the parallel link portions 48a and 48a of the link member 48, In particular, since the connection width between the linkage arm 47 and the other end of the link member 48 can be made sufficiently large, tilting of the link member 48 due to the swinging force of the ball nut 46 can be restricted.

  As a result, the swing of the ball nut 46 can be sufficiently suppressed, so that the movement in the axial direction can be stabilized. For this reason, it is possible to prevent the rotation control accuracy of the control shaft 32 from being lowered and, in turn, to stabilize the valve lift control accuracy.

  Further, since the linkage arm 47 is fixed to the control shaft 32 and swings integrally, there is no tilting of the linkage arm 47, so that the tilting of the link member 48 due to the swinging force of the ball nut 46 is further prevented. it can.

  Furthermore, in this embodiment, the lubricating oil O in the accommodation chamber 35a is splashed up or atomized by the operation of the ball screw transmission mechanism 37, and the upper surface of the connecting portion 48b and each of the upper surfaces of the connecting portion 48b. By adhering to the inner surfaces of the link portions 48 a and 48 a and flowing down, lubricating oil is supplied around the pivotal support portion 55 of the ball nut 46, between the meshing portion with the ball screw shaft 45 and each ball 54. Therefore, the lubricating performance between these members is improved.

  Further, the oil passage 47b is passed through the oil hole 47d through the pin 59 and the pin holes 48d and 48d of the link member 48 and the inner and outer surfaces of the link portions 48a and 48a. It is positively supplied between the nut 46 and the ball screw shaft 45.

  Therefore, the lubrication performance between the ball nut 46 and the ball screw shaft 45 is greatly improved, and the ball nut 46 can be always moved in the axial direction, and the lubrication flowing between the both 45, 46 can be obtained. Since the oil effectively absorbs vibration caused by the alternating torque from the control shaft 32 to the ball nut 46, it is possible to prevent the ball nut 46 from rattling in the axial direction.

  Further, since the link member 48 is only formed by bending and deforming a plate material by press molding, the molding operation is facilitated and the weight can be reduced as compared with a solid case. For this reason, the inertial mass of the link member 48 is reduced, and the moving load of the ball nut 46 can be reduced.

  Further, in this embodiment, since the pivot portion 55 that allows the link member 48 to tilt and swing is provided in the notch groove 56, the pivot portion 55 can be sufficiently brought close to the ball screw shaft 45. Accordingly, it is possible to further promote downsizing of the entire unit body when the link member 48 is tilted.

  That is, since a part of the pivot portion 55 is disposed in the notch groove 56, the link member 48 is also accommodated in the ball nut 46 correspondingly.

Further, since the pivot portion 55 of the link member 48 is formed at the outer end portion of the ball nut 46, it becomes possible to increase the wall thickness of the ball nut 46, thereby ensuring sufficient strength and space. Can do.
The technical ideas other than the invention described in the claims, as grasped from the embodiment, will be described below.

  (1) A hydraulic circuit for supplying and discharging lubricating oil is provided inside the housing, and a part of the lubricating oil supplied from the hydraulic circuit is dropped into the opening of the link member. The actuator of the variable valve operating apparatus according to claim 2 or 3,

  According to this invention, the lubricating oil dripped in the opening is attached to the opposing inner surfaces of the link members and the upper surfaces of the connecting portions and is transmitted downward as they are around the pivotal support portion of the moving nut and the moving nut and the output shaft. Will be actively supplied during. Therefore, the lubricity of these sliding parts and meshing parts is improved.

  (2) The actuator for a variable valve operating apparatus according to claim 2 or 3, wherein lubricating oil is stored in the housing.

  According to the present invention, the lubricating oil in the housing is splashed or fogged by the axial movement of the moving nut accompanying the rotation of the output shaft and the operation of each member such as the linkage arm and the link member. It becomes possible to adhere to the connecting part and each link part from the opening part of the link member, and to sufficiently supply around the above-mentioned pivotal support part and the meshing member between the moving nut and the output shaft.

  (3) The link valve actuator according to any one of claims 1 to 3, wherein the link member is formed by integrally bending a plate material by press molding.

  According to this invention, since it forms by press molding, the manufacturing operation of a link member becomes easy and cost reduction can be achieved.

  The present invention is not limited to the configuration of the above-described embodiment. In addition to forming both ends of the link member 48 in a bifurcated shape by parallel link portions 48a and 48a, only both ends are substantially U-shaped. It is also possible to form. In addition, as the hydraulic circuit, instead of the oil passage 32b of the control shaft 32 or the like, it is also possible to use a different passage configuration outside the housing 35.

  Further, for example, the arrangement of the electric motor 36 can be freely changed according to the layout of the engine room, and may be on the opposite right side instead of the left side shown in FIG. Further, the rotation imparting mechanism may be a hydraulic motor in addition to the electric motor.

  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 screw shaft and the moving nut can be directly meshed with each other without using the ball 54 due to the relationship between the bolt and the nut.

  Further, the present invention can be applied to the exhaust valve side or both valve sides in addition to the intake valve side.

It is a front view which shows the connection state of the link member provided to embodiment of this invention, a linkage arm, and a ball nut. It is a perspective view of the link member provided for this embodiment. It is the sectional view on the AA line of FIG. It is a principal part enlarged view of FIG. 3 which shows the connection state of a linkage arm and a link member. It is operation | movement explanatory drawing of the drive mechanism at the time of the minimum lift control in this embodiment. It is operation | movement explanatory drawing of the drive mechanism at the time of the minimum lift control in this embodiment. It is a perspective view of the variable mechanism and drive mechanism to which this embodiment is applied. It is the perspective view seen from the other of the variable mechanism and drive mechanism to which this embodiment is applied. It is a top view of the variable mechanism and drive mechanism to which this embodiment is applied. It is a perspective view of the variable mechanism provided to this embodiment, and a control mechanism. 10A is a view as viewed in the direction of arrow B in FIG. 10 showing the valve closing action at the time of the minimum lift control in the variable valve apparatus, and FIG. 10B is a view as seen in the direction of arrow B of FIG. 10A is a B arrow view of FIG. 10 showing the valve closing action at the time of maximum lift control in the variable valve apparatus, and B is a B arrow view of FIG. 10 showing the valve opening action at the time of the maximum lift control. It is a valve lift characteristic view of each intake valve by the variable valve operating apparatus of this embodiment.

Explanation of symbols

2 ... Intake valve (engine valve)
4 ... Variable mechanism 6 ... Drive mechanism (actuator)
32 ... Control shaft 35 ... Housing 35a ... Storage chamber 37 ... Ball screw transmission mechanism 45 ... Ball screw shaft 46 ... Ball nut (moving nut)
47 ... Link 48 ... Link member 48a ... Link portion 48b ... Connection portion 48c ... Opening 49 ... Ball circulation groove (screw portion)
55 ... Pivot

Claims (1)

An actuator of a variable valve operating apparatus that changes an operating state of an engine valve by controlling a rotational position of a control shaft according to an engine operating state,
A linkage arm fixed to the control shaft and rotating integrally with the control shaft;
A rotation imparting mechanism that rotationally controls an output shaft having a threaded portion formed on the outer periphery according to the operating state of the engine;
A moving nut that is provided on the outer periphery of the output shaft and moves in the axial direction via the thread portion as the output shaft rotates;
A link member that is swingably connected between the linkage arm and the moving nut, and that converts the movement of the moving nut in the axial direction into a rotational motion and transmits it to the control shaft;
A housing in which a screw transmission mechanism including at least the output shaft, the moving nut, the linkage arm, and the link member is housed and disposed, and a lubricating oil is supplied to the inside;
With
The link member is connected by connecting a pair of substantially parallel plate-like link portions having both ends formed in a bifurcated shape, and opposite edges excluding the both ends so that both ends of the link portions are open. And the cross section is formed in a substantially U shape by the part,
An actuator of a variable valve operating apparatus, wherein both ends of the linkage arm and both sides of a pivot portion formed on a moving nut are sandwiched between the pair of link portions.

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