JP4278604B2 - Variable valve actuator - Google Patents

Description

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

  As a conventional variable valve operating device, one described in the following Patent Document 1 previously filed by the present applicant is 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 for driving the mechanism.

  The actuator includes an electric motor that controls the operation of the variable mechanism via a control mechanism, and a ball screw mechanism that transmits the rotational force of the electric motor to the control shaft at a reduced speed, and the ball screw mechanism is attached to the cylinder head. A motor casing in which each component of the electric motor is accommodated is attached to the end of the housing while being accommodated in a fixed housing.

  Then, the ball screw shaft of the ball screw mechanism is rotated by rotating the electric motor in either the forward or reverse direction by a control signal from the controller according to a change in the engine operation state. The ball nut is moved along the axial direction via a plurality of balls between the grooves on the outer peripheral surface of the screw shaft and the inner peripheral surface of the ball nut.

The movement force of this ball nut is transmitted to the control shaft through the link member and the linkage arm, and the control shaft is rotated in a predetermined direction, thereby variably controlling the operating angle and the opening / closing timing of the intake valve, thereby reducing the engine speed. The engine performance from high to high rotation is improved.
JP 2002-155716 A

  However, in the conventional actuator, a seal member is provided on the output shaft side of the electric motor to prevent intrusion of engine oil or foreign matters such as engine oil for lubricating the ball screw mechanism into the electric motor. However, the electric motor is disposed and fixed horizontally with respect to the cylinder head with respect to the cylinder head together with the motor casing.

  Accordingly, since the seal member is always immersed in the engine oil in the housing, the engine oil enters the inside of the electric motor as the sealing function of the seal member decreases. There is a fear.

  In other words, the seal member may deteriorate due to wear after long-term use and the seal function may deteriorate over time, which makes it easier for engine oil to enter the electric motor via the seal member.

  As a result, the engine oil may adhere to the coil of the electric motor and affect the energization of the coil.

The present invention has been devised in view of the actual situation of the actuator of the conventional variable valve operating device, and in the invention according to claim 1, in particular, between the output shaft of the electric motor and the motor casing. provided with a sealing member, as the oil level of the engine oil to be retained in a housing that houses the speed reduction mechanism, it is immersed traveling nut, and the lower the gravity direction than the sealing surface of the sealing member It is characterized in that arranged in inclined.

According to the present invention, the oil level of the engine oil that causes the actuator to stay in the housing is inclined so that the moving nut is immersed and is lower than the seal surface of the seal member in the direction of gravity. by arranged in Jo, while achieving a sufficient lubrication of the moving nut is the sliding portion of the reduction mechanism also the engine oil in the reduction mechanism inconvenience entering from the periphery of the output shaft into the interior of the electric motor It can be reduced as much as possible .

Therefore, even when the seal member is deteriorated due to wear over time or the like and the seal function is lowered while effectively suppressing the wear in the sliding portion of the speed reduction mechanism , the coil which is a component of the electric motor As a result, the engine oil is prevented from adhering to the power supply as much as possible , and adverse effects on the energization function can be avoided.

Moreover, by the sealing member is interposed between the output shaft and the motor casing of the electric motor, for example, the speed reduction mechanism by Ri splashed on up was the engine oil to the working of be attached before Symbol near the electric motor The sealing member can surely prevent entry into the electric motor.

  Embodiments of an actuator of a variable valve operating apparatus according to the present invention will be described below in detail with reference to the drawings. In this embodiment, the variable valve device is applied to the intake valve side of an in-line four-cylinder internal combustion engine.

  That is, as shown in FIGS. 4 to 6, 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. In addition, two intake valves 2, 2 per cylinder, 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 And an actuator 6 that rotates the mechanism 5 to operate the variable mechanism 4.

  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 fixed to the drive shaft 13 by press-fitting or the like, and an outer periphery of the drive shaft 13. Two swing cams that are swingably supported on the surface and slide in contact with 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. 17 and 17, and a transmission means that is linked between the drive cam 15 and the swing cams 17 and 17 and transmits the rotational force of the drive cam 15 as the swing force of the swing cams 17 and 17.

  As shown in FIG. 4, 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, etc. 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. 5A, 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 described later is provided at the upper end portion of the main bracket 14a. 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 its axis Y is offset from the axis X of the drive shaft 13 in the radial direction by a predetermined amount β. Further, the drive cam 15 is press-fitted and fixed to the drive shaft 13 through one of the drive shaft insertion holes on one outer side that does not interfere with the valve lifters 16 and 16, and the outer peripheral surface has an eccentric circular cam profile. Is formed.

  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. A cam surface 22 is formed on the lower surface, a base circle surface on the camshaft 20 side, a ramp surface extending in an arc from the base circle surface to the cam nose portion 21 side, and a distal end side of the cam nose portion 21 from the ramp surface A lift surface that is continuous with the top surface of the maximum lift of the valve lifter 16 is formed, and the base circle surface, the ramp surface, and the lift surface are located at predetermined positions on the upper surface of each valve lifter 16 according to the swing position of the swing cam 17. It comes to contact.

  As shown in FIGS. 4 to 6, the transmission means includes a rocker arm 23 disposed above the drive shaft 13, a link arm 24 linking the one end portion 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 which will be described later, and one end 23 a is linked to the drive cam 15 via a link arm 24, while the other end 23 b connects the link rod 25. Via the rocking cams 17 and 17.

  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 one end 23a of the rocker arm 23 is rotatably connected to the protruding end 24b via a pin 26.

  Both ends 25a and 25b of the link rod 25 are rotatably connected to the other end 23b of the rocker arm 23 and the cam nose 21 of the swing cam 17 via pins 27 and 28, respectively.

  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. 4, the control shaft 32 is disposed 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. An oil introduction passage 34 for introducing engine oil from an oil gallery (not shown) in the cylinder head 1 is formed in the internal axis direction of the control shaft 32. The control cam 33 has a cylindrical shape as shown in FIGS. 5 and 6, 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 4, the actuator 6 includes a cylinder head 1, a housing 35 fixed to the rear end portion of the head cover 1 a fixed to the upper end portion of the cylinder head 1, and one end portion of the housing 35. An electric motor 36 that is a rotational force applying mechanism fixed to the housing, and a ball screw that is housed in the housing 35 and is a reduction mechanism that transmits the rotational driving force of the electric motor 36 to the control shaft 32 at a reduced speed. And a mechanism 37.

The housing 35 is integrally formed of an aluminum alloy material or the like, and is disposed along the direction substantially perpendicular to the axial direction of the control shaft 32 therein, and an elongated housing chamber 35a in which a ball screw mechanism 37 is housed. A bulging chamber 35b projecting upward at the center of the upper end portion of the storage chamber 35a and facing the one end portion 32a of the control shaft 32 is formed therein, and an operating chamber is constituted by both the chambers 35a and 35b.

The working chambers 35a and 35b are configured such that one end opening is closed by a cover (not shown) via a seal member, while the other end opening communicates with the inside of the cylinder head 1 and the storage chamber. The engine oil directly supplied to the inside of the cylinder head 1 is introduced into the inside of 35a. The storage chamber 35a has a circular opening 35c at one end in the axial direction, and the other end is closed by a wall 35d.

Further, the housing 35 is arranged and fixed at a predetermined angle with respect to the cylinder head 1 so that the wall portion 35d of the storage chamber 35a is on the lower side in the direction of gravity.

Therefore, as shown in FIG. 1, the engine oil introduced into the housing 35 is inclined so that the oil level L is immersed in a ball nut 46 described later and It has become high enough to contact slightly with respect to later-described mechanical seal 3 9a.

  The electric motor 36 is composed of a proportional type DC motor, and a tip end portion 38a of a substantially cylindrical motor casing 38 having components such as coils therein seals one end opening 35c of the housing chamber 35a. Bolts are fixed in a stopped state, and the inclination angle is arranged and fixed in an inclined manner coaxially with the housing 35. In other words, the motor casing 38 is disposed and fixed in an inclined manner at a predetermined angle so that the front end portion 36b of the drive shaft 36a, which is the output shaft of the electric motor 36, is at a lower position in the direction of gravity.

  The electric motor 36 is internally connected via a drive shaft 36a by a mechanical seal 39a which is a seal member provided on the inner peripheral side of a cylindrical retainer 39 press-fitted into the inner peripheral surface of the one end opening 35c. Is sealed.

  Further, 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 and 2, the ball screw 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 the ball screw. A ball nut 46 that is a moving nut screwed to the outer periphery of the shaft 45; a linkage arm 47 that is axially connected to one end portion 32a of the control shaft 32 in the bulging chamber 35b; and the linkage arm 47 and the ball The link member 48 that links the nut 46 is mainly configured, and the link arm 48 and the link member 48 constitute a transmission portion.

  In the ball screw shaft 45, a ball circulation groove 49 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 of the storage chamber 35a and a small diameter portion at the other end. Both end portions 45a and 45b facing each other are rotatably supported by ball bearings 50 and 51, respectively.

  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. In addition, two deflectors for setting the circulation rows 61 and 62 of the plurality of balls 54 at two positions on the front and rear end sides in the axial direction of the ball nut 46 are attached.

  Further, the ball nut 46 is adapted to be given axial movement force while converting the rotational motion of the ball screw shaft 45 into linear motion to the ball nut 46 via each ball 54, and the control. A pivot portion 55 is provided at the outer end portion on the shaft 32 side so that the other end portion of the link member 48 is rotatably supported. 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, and a pivot pin 55a is penetrated and fixed therein.

  The linkage arm 47 has a substantially cylindrical base connected to one end 32a of the control shaft 32, a slit formed at the tapered tip, and an axial center of a pin hole formed at the tip. It is biased from the axis P1 of the control shaft 32.

  The link member 48 is set to a relatively short length, and is formed in a substantially Y-shaped plane as a whole, and includes a flat plate-like one end and a bifurcated other end. The one end is inserted into the slit of the linkage arm 47 and is rotatably connected to the tip by a pin 60 penetrating the pin hole.

  On the other hand, the other end of the bifurcated shape is disposed on both sides of the pivot portion 55, and slidable pin holes are formed through both ends of the pin 55a. And are rotatably connected.

  Therefore, the link member 48 is provided so as to be tilted and swingable substantially along the outer surface axial direction of the ball nut 46 through the pivotal support 55 so as to be substantially parallel to the axial center of the ball screw shaft 45. In the tilted posture, the upper end portion slightly protrudes upward from the outer surface of the ball nut 46.

An oil hole 34a communicating with the oil introduction passage 34 of the control shaft 32 is formed through the large-diameter base portion of the linkage arm 47, and the engine oil flowing down from the oil hole 34a through the preparative along the one end and the outer surface of the other end of the link member 47 is provided on the outer surface of the pivot portion 55 in and the ball nut 46, further the ball nut 46 both ends each guide groove 53 of the While being stored, it is dropped into the housing 35.

  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 54 rolls between the ball circulation groove 49 and the guide groove 53 with this rotation, and the ball nut 46 is moved to the maximum leftward position as shown in FIG. Move in a straight line.

  As a result, the control shaft 32 is rotationally driven clockwise by the link member 48 and the linkage arm 47. 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. 5A and 5B, 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, when the engine is shifted to the high engine speed region, the electric motor 36 is rotated in reverse by a control signal from the controller 40. When this rotational 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. 2 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. 5 to rotate the shaft center P2 downward as shown in FIGS. 6A and 6B. 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 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.

In this embodiment, as described above, the oil surface of the engine oil that causes the actuator to stay in the housing 35 immerses the ball nut 46 and is more gravitational than the seal surface of the mechanical seal 39a. The engine oil in the housing 35 is disposed in the housing 35 while the ball nut 46 which is a sliding portion of the ball screw mechanism 37 is sufficiently lubricated by being disposed in an inclined manner so as to be on the lower side with respect to the direction. Problems such as intrusion into the motor casing 38 from the periphery of the drive shaft 36a can be reduced as much as possible .

Accordingly, even when the mechanical seal 39a is deteriorated due to wear over time or the like and the sealing function is lowered while effectively suppressing the wear at the sliding portion of the ball screw mechanism 37, the components of the electric motor 36 are reduced. As a result, the adhesion of engine oil to the coil or the like is suppressed as much as possible , and adverse effects on the energization function can be avoided.

Moreover, the electric mechanical seal 39a between the drive shaft 36a and the motor casing 38 of the motor 36 that is interposed, for example the ball engine oil the drive shaft 36a has bounced above up by such actuation of the screw mechanism 37 It is attached to Ri circumference, as much as possible to suppress the intrusion into the internal motor casing 38 by the mechanical seal 39a.

The housing 35 has a working chamber 35a and the like that communicates with the inside of the cylinder head 1 and directly introduces engine oil in the cylinder head 1 into the inside of the cylinder head 1. It becomes possible to lubricate each part more effectively.

  In this embodiment, the engine oil supplied from the oil introduction passage 34 to the periphery of the ball nut 46 through the oil hole 34a and the outer surface of the link member 48 is the ball nut 46 in which the ball 54 is not disposed. Are sufficiently stored in the recesses of the guide grooves 53, so that when the ball nut 46 is linearly moved, the previously stored engine oil adheres to the outer surfaces of the plurality of inner balls 54 and the like. In order to effectively lubricate between the ball circulation groove 49 and the guide groove 53, the rotation of the ball screw shaft 45 and the linear movement of the ball nut 46 can be performed more smoothly.

  Further, the engine oil stored in the guide grooves 53 on both end sides is gradually supplied also between the both ball circulation rows 61 and 62, and the engine oil can also be stored here. improves.

  The technical ideas other than the invention described in the claims, as grasped from the embodiment, will be described below.

  (1) The actuator for a variable valve operating apparatus according to claim 3, wherein a part of the control shaft is inserted and disposed in the housing.

  It becomes possible to effectively lubricate a part of the control shaft, a connecting portion with the speed reduction mechanism, and the like by the engine oil previously retained in the housing.

  (2) The actuator of the variable valve operating apparatus according to (3) or (1), wherein the interior of the housing is communicated with the interior of a cylinder head.

  Since engine oil for lubricating the valve gear in the cylinder head can be introduced and retained in the housing as it is, each sliding part such as a speed reduction mechanism can be lubricated with a simple lubrication configuration. Become.

(3) The electric motor for controlling the rotation of the output shaft having a threaded portion formed on the outer periphery thereof according to an engine operating state;
A moving nut that meshes with the threaded portion and is movable in the axial direction according to the rotation of the output shaft;
A transmission unit that converts the movement of the moving nut in the axial direction into a rotary motion and transmits the rotational movement to the control shaft;
The actuator of the variable valve operating apparatus according to any one of claims 1 to 2, wherein the actuator is provided.

(4) A lever member that swings integrally with the control shaft, the transmission unit;
The actuator of the variable valve operating apparatus according to claim 3, characterized in that the lever member and a link connected to each other so as to be swingable with respect to the lever member.

(5) The variable valve operating device comprises:
A drive shaft that is rotationally driven by the crankshaft of the engine, and a drive cam integrally fixed to the outer periphery;
A link arm that rotatably supports the drive cam;
A rocker arm that is swingably supported by the control shaft via a control cam, and one end side of which is rotatably linked to the link arm;
A link rod whose one end is rotatably linked to the other end of the rocker arm;
A swing cam linked to the other end of the link rod so as to be swingable and opening / closing the engine valve by a swing motion transmitted from the rocker arm via the link rod;
The actuator of the variable valve operating apparatus according to any one of claims 1 to 4, wherein the actuator is provided.

  The present invention is not limited to the configuration of the above-described embodiment. For example, the arrangement of the electric motor 36 and the ball screw mechanism 37 can be freely changed according to the layout of the engine room, but as described above. The inclined arrangement must be maintained. In addition to the intake valve side, the present invention can be applied to the exhaust valve side or both valve sides.

It is a principal part side view which partially shows the state which fixed the actuator of the variable valve apparatus which concerns on this invention to the internal combustion engine in the inclined form. It is a principal part side view at the time of the minimum lift of the actuator of this embodiment. It is a perspective view of an actuator provided for this embodiment. It is a perspective view of the variable valve apparatus to which this embodiment is applied. 4A is a view as viewed in the direction of an arrow A in FIG. 4 showing the valve closing action at the time of the minimum lift control in the variable valve apparatus, and FIG. 5B is a view taken in the direction of the arrow A in FIG. 4A is a view as viewed in the direction of an arrow A in FIG. 4 showing the valve closing action at the time of maximum lift control in the variable valve apparatus, and FIG. 5B is a view taken in the direction of the arrow A in FIG.

Explanation of symbols

2 ... Intake valve (engine valve)
4 ... Variable mechanism 6 ... Actuator 32 ... Control shaft 34 ... Oil introduction passage 35 ... Housing 37 ... Electric motor 38 ... Motor casing 37 ... Ball screw mechanism (deceleration mechanism)
45 ... Ball screw shaft 46 ... Ball nut (moving nut)
47. Linking arm (transmission part)
48 ... Link member (transmission part)

Claims (1)

A reduction mechanism that is housed in a housing and lubricated by engine oil retained in the housing, and an electric motor in which components are housed in a motor casing fixed to the housing. in the actuator of the variable valve device for opening and closing characteristic of the engine valve variable by transmitting rotation of the output shaft of the electric motor to the control shaft via,
A screw shaft that has a threaded portion on the outer periphery, the rotation mechanism being linked to the output shaft and controlled to rotate by the electric motor;
A moving nut that is screwed into the threaded portion and is movable in the axial direction according to the rotation of the screw shaft;
A transmission unit that converts the movement of the moving nut in the axial direction into a rotary motion and transmits it to the control shaft;
While providing a seal member between the output shaft and the motor casing,
Yes oil level of the engine oil to the stagnation, is immersed the moving nut, and such that the lower the gravity direction than the sealing surface of the sealing member, characterized in that arranged in the inclined Actuator for variable valve device.

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