JP2007211752A - Actuator for valve lift control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve heat radiation performance of a linear motion mechanism which converts rotary motion to linear motion. <P>SOLUTION: An actuator 10 is used for a valve lift control device controlling lift of a control object valve 6, and linearly controls a control shaft 12 of a change mechanism 8 changing lift according to axial direction position of the control shaft 12. The actuator includes a screw shaft 39 linearly moving in an axial direction together with the control shaft 12, and a rotary shaft 38 (nut 41) arranged concentrically with the screw shaft 39 and rotating, and is also provided with: a feed screw mechanism 21 converting rotary motion of the rotary shaft 38 to linear motion of the screw shaft 39; a motor part 26 provided in an anti-control shaft side of the rotary shaft 38 and rotating the rotary shaft 38 by electricity supply; and an oil supply passage 34, 36 making oil flow between a first circumference area (a first inner space) 49 in the anti-control shaft side of the rotary shaft 38 and second circumference area (a first space and a second inner space) 32, 46. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an actuator for a valve lift control device, and is suitable for application to an actuator of a valve lift control device that controls the lift amount of at least one of an intake valve and an exhaust valve of an internal combustion engine, for example.

  Conventionally, in a valve lift control device, various actuators are used to linearly drive the control shaft of a changing mechanism that changes the lift amount of a control target valve in accordance with the axial position of the control shaft.

For example, Patent Document 1 discloses an actuator that linearly moves a control shaft of a change mechanism using oil pressure. In this technique, a piston interlocked with a control shaft, a space for housing the piston, a first hydraulic chamber and a second hydraulic chamber that are partitioned in the axial direction with the piston interposed therebetween, and the first hydraulic chamber and the first hydraulic chamber are separated by a flow control valve. The control shaft is linearly driven in the axial direction by selectively supplying oil to the second hydraulic chamber.
JP 2001-263015 A

  When the oil pressure is used, it may be difficult to control with high accuracy when the hydraulic control conditions become severe, for example, in a low temperature environment or immediately after the start of the internal combustion engine.

  Therefore, the inventors use a mechanism such as a feed screw mechanism that uses the rotational force of an electric motor such as a motor unit to convert the rotational motion of the rotational shaft transmitted by the rotational force into the linear motion of the screw shaft. We are studying the so-called linear motion mechanism. When such a linear motion mechanism is applied to an actuator, a relatively large linear driving force is obtained by a configuration in which a rotation shaft and a screw shaft that are coaxial with each other are directly or indirectly connected to each other, so that heat is easily generated. There is. If this linear motion mechanism generates heat, there is a possibility that the temperature of the motor unit rises and the drive circuit of the control device that drives and controls the motor unit is affected.

  On the other hand, it is conceivable that oil is injected into the linear motion mechanism and the oil for cooling is stored, but if it does not circulate after the storage, there is a limit to heat dissipation.

  The present invention has been made in view of such circumstances, and an object of the present invention is to improve the heat dissipation of a linear motion mechanism that converts rotational motion into linear motion.

  Another object of the present invention is to provide an actuator for a valve lift control device that can improve the heat dissipation of the linear motion mechanism and improve the reliability of the operating members linked in the linear motion mechanism.

  In order to achieve the above object, the present invention comprises the following technical means.

That is, according to the first to seventh aspects of the present invention, the lift amount is used in a valve lift control device that controls the lift amount of at least one of the intake valve and the exhaust valve of the internal combustion engine, and the lift amount is determined in the axial position of the control shaft. In an actuator for a valve lift control device that linearly drives a control shaft of a change mechanism that changes according to
A feed screw mechanism that has a screw shaft that linearly moves in the axial direction together with the control shaft, and a rotary shaft that is arranged coaxially with the screw shaft and that rotates, and converts the rotary motion of the rotary shaft into linear motion of the screw shaft; A motor unit that is provided on the counter-control shaft side of the shaft and that rotates the rotation shaft by energization; a first peripheral region on the counter-control shaft side of the rotation shaft; and a second peripheral region on the control shaft side of the rotation shaft And a hydraulic oil supply path through which hydraulic oil flows.

  According to this, since the hydraulic oil supply path through which the hydraulic oil flows between the first peripheral area on the opposite side of the rotary shaft on the side opposite to the control axis and the second peripheral area on the control axis side of the rotary shaft is provided, In a feed screw mechanism for linear drive, supply hydraulic oil so that hydraulic oil such as engine oil flows between the rotary shaft and screw shaft that converts rotational motion into linear motion by the hydraulic oil supply path. Can do.

  Therefore, it is possible to improve the heat dissipation of a linear motion mechanism such as a feed screw mechanism that converts a rotational motion into a linear motion by circulation of hydraulic oil such as engine oil flowing in the linear motion mechanism.

  In particular, in the invention described in claim 2, the screw shaft is disposed in the rotating shaft, and the first circumferential region is partitioned by the rotating shaft and the screw shaft disposed in the rotating shaft. It is characterized by that.

  According to this, since the 1st peripheral region where the hydraulic oil of a hydraulic-oil supply path | route flows is divided by the rotating shaft and the screw shaft arrange | positioned in a rotating shaft, the rotation which converts rotational motion into linear motion It is possible to reliably flow the hydraulic oil between the shaft and the screw shaft.

  In the invention according to claims 3 to 4, the hydraulic oil supply path includes a first inlet for guiding the hydraulic oil to the first peripheral area and a second inlet for guiding the hydraulic oil to the second peripheral area. The hydraulic oil circulates in the first peripheral region and the second peripheral region.

  Thereby, between the rotating shaft which converts rotational motion into linear motion, and a screw shaft, it can be forcedly circulated with the hydraulic fluid which flows through a hydraulic-oil supply path | route.

  In particular, in the invention described in claim 4, the screw shaft includes a through hole that opens in the screw shaft to the first peripheral region side, and the opening portion forms a first guiding port. And

  According to this, the screw shaft is provided with a through-hole having an opening that opens to the first peripheral region side, and the opening serves as a first guide port that guides hydraulic oil to the first peripheral region. Even if the first peripheral region and the second peripheral region are relatively separated, a hydraulic oil supply path through which the hydraulic oil flows between the first peripheral region and the second peripheral region is relatively simple. can do.

  In the invention according to claim 5, a joint member that rotatably connects the opposing ends of the screw shaft and the control shaft is provided, and the through hole extends so as to open to the end of the rotating shaft. It is characterized by.

  In general, in a joint member that rotatably connects opposite ends of a screw shaft and a control shaft, a relatively large tensile force acts on the control shaft by a valve operation of a control target that changes a lift amount by the control shaft. Each time the tensile force is generated, the end of the control shaft, the end of the screw shaft, and the joint member connecting the ends are added to the end of the control shaft, the end of the screw shaft, and the joint member. Easy to wear out.

  On the other hand, in the invention described in claim 5, it is preferable that the through hole through which the hydraulic oil is guided extends so as to open at the end of the screw shaft. As a result, the hydraulic oil flowing through the hydraulic oil supply path is passed through the through hole extending so as to open to the end of the screw shaft, and the end of the control shaft, the end of the screw shaft, and the joint member that connects these ends. Can lead to.

Further, in the invention according to claim 6, the inner ring is attached to the rotating shaft, and is arranged between the rolling bearing that rotatably supports the rotating shaft, the second peripheral region, and the rolling bearing, An oil seal for sealing the hydraulic oil guided to the second peripheral area,
The hydraulic oil supply path is characterized in that the hydraulic oil is introduced from the second peripheral area and is discharged from the first peripheral area.

  In general, when an oil seal is provided between the second peripheral area and the rolling bearing to seal the hydraulic oil guided to the second peripheral area, the oil seal is supplied from the hydraulic oil supply path due to the pressure resistance of the oil seal. It is necessary to minimize the amount of hydraulic oil.

  On the other hand, in the invention according to the sixth aspect, the hydraulic oil supply path introduces the hydraulic oil from the second peripheral area and discharges the hydraulic oil from the first peripheral area. It is easy to adjust the amount so that the hydraulic pressure in the second peripheral region is equal to or lower than the pressure resistance.

  According to a seventh aspect of the present invention, a partition member that separates the motor portion and the first peripheral region is provided, and the partition member is attached to the rotating shaft.

  According to this, between the rotating shaft and the screw shaft that need to be cooled is cooled with hydraulic oil, the inside of the motor unit is hermetically sealed with the partition member, and the motor unit that needs to be cooled is sealed with hydraulic oil through the partition member. It is possible to cool.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments in which an actuator for a valve lift control device according to the present invention is applied to a valve lift control device that controls a lift amount of an intake valve of an internal combustion engine (hereinafter referred to as an engine) will now be described with reference to the drawings. FIG. 1 is a partial cross-sectional view showing an actuator of the valve lift control device according to the present embodiment. 2A and 2B are schematic views showing the valve lift control device according to the present embodiment, in which FIG. 2A is an axial partial sectional view of a control shaft, and FIG. 2B is a radial sectional view. FIG. 3 is a cross-sectional view showing the actuator of the valve lift control device according to the present embodiment.

  The change mechanism 8 has the configuration shown in FIG. 2 as disclosed in, for example, Japanese Patent Application Laid-Open No. 2001-263015, and is incorporated in the engine 4. Specifically, as shown in FIG. 2A, the changing mechanism 8 includes a slider gear 14 that can move linearly with the control shaft 12 in the axial direction of the control shaft 12 and a helical spline fit on the input portion 15 and the swing cam 16. The relative phase difference between the input unit 15 and the swing cam 16 changes according to the axial position of the control shaft 12.

  Further, as shown in FIG. 2B, the input portion 15 is in contact with the intake cam 18 of the cam shaft 17, and the swing cam 16 is provided so as to be in contact with the rocker arm 19 of the intake valve 6. The rocking angle of the rocker arm 19 changes according to the relative phase difference between the portion 15 and the rocking cam 16. Accordingly, in the change mechanism 8, the lift amount of the intake valve 6 (hereinafter simply referred to as the valve lift amount) changes in accordance with the change in the axial position of the control shaft 12, thereby the operating angle and the maximum valve lift amount. The valve characteristics such as are adjusted.

  In this embodiment, the valve reaction force transmitted from the intake valve 6 to the control shaft 12 acts on the control shaft 12 as a thrust force directed to the side opposite to the actuator 10.

  As shown in FIGS. 2A and 2B, the actuator 10 linearly drives the control shaft 12 of the change mechanism 8 in the axial direction. Specifically, as shown in FIG. 3, the actuator 10 includes a main body case 20, a feed screw mechanism 21, a thrust bearing 22, a radial bearing 23, an oil seal 24, a displacement restricting portion 25, a motor portion 26, a magnet portion 27, and a sensor. Part 28 and energizing part 29. The actuator 10 is mounted on the vehicle so that the left-right direction in FIG. 3 is substantially horizontal.

  As shown in FIG. 3, the main body case 20 is formed in a bottomed cylindrical shape, and is bolted to the engine 4 with the bottom portion 31 fitted in the mounting hole 30 of the engine 4. The body case 20 has a space 32 (hereinafter referred to as a first space) 32 and a second space 33 adjacent to each other in the axial direction. In FIG. 3, a boundary line B between the first space 32 and the second space 33 is schematically shown by a two-dot chain line.

  As shown in FIGS. 1 and 3, the feed screw mechanism 21 is a trapezoidal screw mechanism formed by combining a rotary shaft 38 and a screw shaft 39 that are arranged coaxially with each other. The rotation shaft 38 is formed in a substantially cylindrical shape as a whole, and is disposed across the first space 32 and the second space 33, so that the rotation shaft 38 is interposed between the energizing portion 29 and the control shaft 12 of the change mechanism 8. positioned.

  As shown in FIG. 1, the rotary shaft 38 includes a nut 41 in which a female screw 40 having a trapezoidal cross section is cut on the inner peripheral wall. The nut 41 includes a lid 42 attached to the nut 41, and an engagement member. A circlip 43 is provided as a stop member. The nut 41 is supported by a thrust bearing 22 and a radial bearing 23 arranged coaxially therewith, so that the nut 41 can be rotated forward and backward in the circumferential direction. One end 41 a of the nut 41 opens into the first space 32, and the other end 41 b of the nut 41 is closed by the lid 42 in the second space 33. The circlip 43 is formed in a C shape or the like and is fitted in the circumferential groove 45 of the outer peripheral wall of the nut 41, and is not relatively displaceable relative to the nut 41 in the axial direction.

  The lid 42 is formed in a substantially cylindrical shape coaxial with the nut 41. The lid 42 includes a partition wall portion 44a, a fitting portion 44b, and a sleeve portion 44c. The partition wall 44 a is formed in a substantially disk shape and closes the opening of the other end 41 b of the nut 41. Further, the fitting portion 44b is formed in a substantially cylindrical shape extending from the outer peripheral portion of the partition wall portion 44a to the control shaft 12 side, and is liquid-tightly attached to the inner periphery of the other end portion 41b via an O-ring 98 as a seal member. Has been. An inner space (hereinafter referred to as a first inner space) 49 is formed by the partition wall 44 a and the fitting portion 44 b of the lid 42, the other end 41 b of the nut 41, and the screw shaft 39. The lid 42 provides a liquid-tight seal between the first internal space 49 and the space 33. The first internal space 49 is sealed in a liquid-tight manner with respect to the space 33, and oil can be stored in the space 49 in a liquid-tight manner. Furthermore, the sleeve portion 44c extends in a cylindrical shape so as to open from the outer peripheral portion of the partition wall portion 44a toward the energizing portion 29 side.

  The configuration of the first internal space 49 and the oil circulation path that guides oil to the space 49 will be described later.

  The screw shaft 39 is inserted through the bottom 31 of the main body case 20 to the engine 4 side, and in order from the engine 4 side, the oil passage 47 of the engine 4, the first space 32, and the nut 41 on the control shaft 12 side. 2 is disposed across the internal space 46. The screw shaft 39 is located between the energizing portion 29 and the control shaft 12 of the change mechanism 8. In addition, a male screw 48 having a trapezoidal cross section is provided on the outer peripheral wall of the end portion on the nut 41 side of the screw shaft 39, and the male screw 48 is configured to be screwed with the female screw 40 of the nut 41. . Thereby, the screw shaft 39 is displaced in the axial direction by the rotation of the rotation shaft 38. That is, in the feed screw mechanism 21, the rotational motion of the rotary shaft 38 is converted into the axial motion of the screw shaft 39, and the rotational drive of the rotary shaft 38 is converted into the linear drive of the screw shaft 39.

  As shown in FIG. 3, the end 39j of the screw shaft 39 on the oil passage 47 side is coaxially connected to the end 12j of the control shaft 12 opposite to the slider gear 14 via a joint member 99. ing. As a result, the screw shaft 39 can move linearly with the control shaft 12 and is urged toward the control shaft 12 in the axial direction by the valve reaction force.

  The joint member 99 is rotatably connected to both end portions 12j and 39j, and the tensile force due to the valve reaction force is connected to the end portion 12j, the end portion 39j and the joint member 99 connected to the end portions 12j and 39j. Works.

  As shown in FIG. 1, the screw shaft 39 has an involute spline 50 formed on the outer peripheral wall at the intermediate portion between the male screw 48 and the end 39j. An involute spline 52 is formed on the inner peripheral wall of a bush 51 (hereinafter referred to as a rotation restricting bush) 51 that is fitted to the bottom 31 in the main body case 20 so as to be unevenly fitted in the involute spline 50 in the radial direction. .

  By fitting these involute splines 50 and 52 together (hereinafter referred to as involute fitting), the sliding resistance of the screw shaft 39 with respect to the rotation restricting bush 51 can be reduced, and the rotation and misalignment of the screw shaft 39 can be regulated. I'm. The motion conversion efficiency in the feed screw mechanism 21 is enhanced by such involute fitting.

  The thrust bearing 22 that supports the thrust force acting on the rotating shaft 38 is disposed in the first space 32. As shown in FIGS. 1 and 3, the thrust bearing 22 is an axial contact ball bearing in which a ball-shaped rolling element 55 is sandwiched between an inner ring 53 and an outer ring 54. The thrust bearing 22 is not limited to this, and may be an angular contact type or an axial contact type roller bearing, and may have any structure as long as it supports a thrust force acting on the rotating shaft 38. .

  The outer ring 54 is fitted to the inner peripheral wall of the main body case 20. The inner ring 53 is engaged with the end 41a of the nut 41 from the axial control shaft 12 side, and the outer ring 54 is engaged with the bottom 31 of the main body case 20 from the axial control shaft 12 side.

  The radial bearing 23 that supports the radial force acting on the rotating shaft 38 is disposed in the second space 33. As shown in FIGS. 1 and 3, the radial bearing 23 is a radial contact type ball bearing in which a ball-shaped rolling element 58 is sandwiched between an inner ring 56 and an outer ring 57. The radial bearing 23 is not limited to this, and may be an angular contact type roller bearing or an angular contact type ball bearing, and may have any structure as long as it supports a radial force acting on the rotary shaft 38. Also good.

  The inner ring 56 is fitted and attached to the outer peripheral wall of the nut 41, and the circlip 43 is engaged with the inner ring 56 from the control shaft 12 side in the axial direction. The outer ring 57 is fitted to the inner peripheral wall of the retainer portion 59 protruding in a cylindrical shape from the inner wall of the main body case 20.

  The oil seal 24 is interposed between the main body case 20 and the end 41 a of the nut 41. The oil seal 24 is disposed on the boundary line B between the first space 32 and the second space 33, and is located on the opposite side of the radial bearing 23 with the circlip 43 interposed therebetween.

  The displacement restricting portion 25 includes a stopper 60 and a wave washer 61 as an elastic member, and is disposed in the second space 33. The stopper 60 has a fitting part 62, a fixing part 63, and a locking part 64. The fitting portion 62 is formed in a cylindrical shape and is fitted to the outer peripheral wall of the retainer portion 59 of the main body case 20. The fixing portion 63 is formed in an annular plate shape protruding from the one end portion of the fitting portion 62 to the outer peripheral side, and is screwed to the inner wall of the main body case 20. The locking portion 64 is formed in an annular plate shape protruding from the other end portion of the fitting portion 62 toward the inner peripheral side, and is disposed closer to the energizing portion 29 than the outer ring 57 in the axial direction of the radial bearing 23.

  An annular plate-shaped wave washer 61 is interposed between the locking portion 64 and the outer ring 57. The wave washer 61 is disposed coaxially with the locking portion 64 and the outer ring 57 and is compressed in the axial direction. Due to this compression, a restoring force is generated in the wave washer 61, and this restoring force acts on the outer ring 57 as a thrust force that urges the radial bearing 23 toward the control shaft 12 side. Further, since the restoring force of the wave washer 61 acts not only on the outer ring 57 but also on the locking part 64 as a thrust force toward the energizing part 29 side, movement in the thrust direction between the locking part 64 and the outer ring 57 is performed. Is to be reduced.

  As shown in FIG. 1, the motor unit 26 is a brushless motor formed by combining a rotary rotor 65 and a stator 66, and is disposed in the second space 33. The rotary rotor 65 has a rotor core 67 formed by laminating annular plate-shaped iron pieces, and a permanent magnet 68 and a magnet cover 69 attached to the rotor core 67. The rotor core 67 is coaxially fitted to the outer peripheral wall of the end portion 41 b of the nut 41, and can rotate forward and backward together with the rotary shaft 38. That is, the rotating shaft 38 also functions as a motor shaft in the motor unit 26. Permanent magnets 68 are embedded in a plurality of locations at equal intervals in the circumferential direction in the vicinity of the outer peripheral edge of the rotor core 67. The magnet cover 69 is a non-magnetic material and is formed in an annular plate shape, and is provided on each side of the rotor core 67 in the axial direction. Thus, the two magnet covers 69 are positioned in the axial direction with a plurality of permanent magnets 68 interposed therebetween.

  The stator 66 is disposed on the outer peripheral side of the rotary rotor 65, and has an annular plate-shaped stator core 70 having a plurality of protrusions 70a protruding toward the inner periphery, coils 71 provided corresponding to the protrusions 70a, and A bobbin 72 is provided. The stator core 70 is formed in a block shape by stacking iron pieces and is attached to the inner peripheral wall of the main body case 20. A coil 71 is wound around each protrusion 70 a of the stator core 70 via a bobbin 72.

  The magnet unit 27 includes a magnet holder 74 and a permanent magnet 75 having a plurality of magnetic poles on the end surface on the sensor unit 28 side, and is disposed in the second space 33. The magnet holder 74 is formed of a magnetic material, and is rivet-fixed together with the magnet cover 69 on the energizing portion 29 side of the rotor core 67. The permanent magnet 75 is positioned and held at a predetermined position of the magnet holder 74 by utilizing the concave-convex fitting and the magnetic action. Therefore, the magnet portion 27 composed of the permanent magnet 75 and the magnet holder 74 can rotate forward and backward together with the rotating rotor 65 and the rotating shaft 38.

  The sensor unit 28 includes a plurality of Hall elements 76, is disposed closer to the energization unit 29 than the magnet unit 27 in the axial direction of the rotation shaft 38, and is exposed to the second space 33. Each Hall element 76 is held at a predetermined position of the energization unit 29, and detects the rotation angle of the rotation shaft 38 by receiving a magnetic action from the permanent magnet 75 of the magnet unit 27. And the sensor part 28 and the magnet part 27 are comprised so that the output of each Hall element 76 may show predetermined | prescribed correlation with respect to the rotation angle of the rotating shaft 38 which changes the position of each magnetic pole of the permanent magnet 75. FIG. . In this embodiment, a Hall element is used for the sensor unit 28, but the present invention is not limited to this, and a sensor element such as a magnetoresistive element may be used. Further, the number of sensor elements such as the Hall element 76 can be set as appropriate.

  As shown in FIG. 3, the energization unit 29 includes a circuit case 80 that is bolted to the main body case 20, and a drive circuit 81 that is accommodated in the circuit case 80. The circuit case 80 includes a base member 82 and a cover member 83 both formed in a cup shape. The base member 82 covers the opening of the main body case 20 by the bottom portion 84, and opens toward the side opposite to the main body case 20. As shown in FIG. 1, the base member 82 includes a support portion 85 that protrudes from the bottom portion 84 toward the main body case 20. The support portion 85 is formed in a cylindrical shape and is coaxially inserted into the sleeve portion 44 c of the lid 42.

  The relationship between the wave washer 61 and each gap is preferably set as follows. In the axial direction of the rotating shaft 38 in the state where the thrust force is not acting, the gap amount C1 between the elements 76 and 75 when the Hall element 76 and the permanent magnet 75 are facing each other is larger than the maximum compression amount of the wave washer 61. Also, the sensor unit 28 and the magnet unit 27 are arranged so as to be larger. The base member 82 and the rotary shaft are set so that the gap amount C2 between the bottom portion 84 and the sleeve portion 44c and the gap amount C3 between the support portion 85 and the lid 42 are larger than the maximum compression amount of the wave washer 61. 38 is arranged. Here, the maximum compression amount refers to the maximum value of the compression amount allowed for the wave washer 61 in a state where the thrust force is not acting on the rotating shaft 38.

  A cylindrical sliding bush 86 is interposed between the support portion 85 and the sleeve portion 44 c, and the sleeve portion 44 c is supported by the support portion 85 via the sliding bush 86. As a result, the radial displacement of the sleeve portion 44c is restricted, so that the rotation shaft 38 is prevented from being inclined with the bearing portion of the radial bearing 23 as a fulcrum.

  As shown in FIG. 3, the opening edge of the base member 82 overlaps the opening edge of the cover member 83 so as to be liquid-tight, and a space 87 surrounded by the base member 82 and the cover member 83. A drive circuit 81 is disposed inside. The drive circuit 81 is an electric circuit in which a plurality of substrates 89 on which circuit elements 88 are mounted are arranged in the axial direction of the rotary shaft 38. The drive circuit 81 is electrically connected to each coil 71 of the motor unit 26 and is electrically connected to a control circuit 90 outside the circuit case 80 via a terminal (not shown).

  Further, as shown in FIG. 1, a substrate in which each Hall element 76 of the sensor unit 28 is mounted between the substrate 89 a fitted and held on the bottom 84 of the base member 82 in the drive circuit 81 and the bottom 84. 91 is interposed, and the drive circuit 81 is also electrically connected to the Hall elements 76. Each Hall element 76 mounted on the substrate 91 is exposed to the second space 33 through a through hole 92 that penetrates the bottom 84 of the base member 82.

  The control circuit 90 is an electric circuit that recognizes the rotation angle of the rotary shaft 38 and further the axial position of the control shaft 12 by receiving the output of each Hall element 76 through the drive circuit 81. Further, the control circuit 90 estimates the actual valve lift amount from the recognized axial position of the control shaft 12, and supplies the energization for reducing the difference between the actual valve lift amount and the target valve lift amount to the drive circuit 81. To In response to this command, the drive circuit 81 controls energization of the coils 71 to excite the coils 71 in a predetermined order to rotationally drive the rotary rotor 65 and the rotary shaft 38. As a result, the screw shaft 39 and the control shaft 12 are linearly driven in the axial direction to reduce the difference, so that the target valve lift amount is realized. The target valve lift amount is a physical amount that is determined based on the driving state of the vehicle such as the engine speed and the accelerator opening.

  Next, the characteristic part of the actuator 10 will be described in more detail. As shown in FIGS. 1 and 3, the first space 32 located closer to the bottom 31 than the second space 33 is provided with an engine operation from an oil pump 35 of the engine 4 through an oil supply hole 34 penetrating the main body case 20. Lubricating oil (hereinafter referred to as oil) such as engine oil is supplied as oil. Further, the oil in the first space 32 is discharged to the oil passage 47 outside the main body case 20 through the gap between the screw shaft 39 and the rotation restricting bush 51. In the engine 4, the oil discharged to the oil passage 47 is returned to the oil pump 35.

  Here, the second space 33 is a space in which an electric motor mainly composed of a motor unit is arranged and gas such as an atmosphere is kept airtight. The first space 32 is a space in which a so-called linear motion mechanism having a feed screw mechanism as a main body is arranged, and oil is guided into the interior and kept liquid-tight.

  In the present embodiment, the first internal space 49 and the second internal space 46 are disposed in both end portions 41a and 41b of the nut 41 that movably accommodates the screw shaft 39 in the rotary shaft 38. . The first internal space 49 and the second internal space 46 are configured to communicate with the first space 31 and constitute a part of the first space 32 into which oil is guided. The first internal space 49 and the first space 32 communicate with each other through a gap between the male screw of the screw shaft 39 and the female screw of the nut 41.

  Furthermore, in the present embodiment, the first internal space 49 communicates with an oil passage 47 for collecting excess oil to the oil pump 35. Specifically, as shown in FIGS. 1 and 3, the screw shaft 39 is provided with an oil discharge hole 36 extending in the axial direction, and the opening 36a of the oil discharge hole 36 has a first internal space. 49 is open. The oil discharge hole 36 communicates with the oil passage 47 through a communication hole 37 formed in the screw shaft 39 on the oil passage 47 side.

  Note that the oil discharge hole 36 is preferably a through-hole penetrating to the end 39j.

  Furthermore, the opening 34 a that opens to the first space 32 side of the oil supply hole 34 is narrowed so as to limit the flow rate of the oil flowing into the first space 32. Specifically, as shown in FIG. 1, the opening area of the opening 34a is reduced to a predetermined area by, for example, an overlapping portion of the outer ring 54 of the thrust bearing 22 and the opening 34a.

  Here, the oil flow rate limited by the throttle is equal to or less than the amount of oil flowing into the space 32 from the oil supply hole 34 where the oil pressure in the space 32 is equal to or less than the pressure resistance of the oil seal 24, and the screw shaft 39. And the oil inflow amount that allows oil to flow from the space 32 to the first internal space 49 through the gap between the nut 41 and the nut 41. Further, in such an oil flow range, in order to keep the oil pressure drop on the engine side relatively small by the oil inflow amount, it is preferable to set the lower limit side of the range.

  Here, the oil corresponds to the hydraulic oil described in the claims. The first space 32 and the second internal space 46 constitute a second peripheral region on the control shaft side of the rotation shaft described in the claims. Further, the first internal space 49 constitutes a first peripheral region on the counter-control shaft side of the rotation shaft described in the claims.

  Furthermore, the oil supply hole 34 and the oil discharge hole 36 are oil supply paths through which oil circulates by the supply of oil from the oil pump 35, and constitute the hydraulic oil supply path described in the claims. The opening 34a of the oil supply hole 34 corresponds to the second guide port described in the claims, and the opening 36a of the oil discharge hole 36 is the first guide port described in the claims. It corresponds to.

  Furthermore, the lid 42 constitutes a partition member described in the claims. Moreover, the radial bearing 23 comprises the rolling bearing as described in a claim. The intake valve 6 corresponds to a control target valve that changes the lift amount by the control shaft 12.

  In the present embodiment described above, in the feed screw mechanism 21, the first space 32 and the second internal space 46 that are liquid-tightly sealed are provided on the control shaft 12 side of the nut 41 that is the rotation shaft 39, and the nut 41 is also provided. A first inner space 49 that is liquid-tightly sealed is provided on the opposite control shaft side. The oil supply passages 34 and 36 have an oil supply hole 34 that opens to the first space 32 and an oil discharge hole 36 that opens to the first internal space 49, and the oil is supplied by the oil pump 35 on the engine side. Is provided.

  With this configuration, in the feed screw mechanism 21, the first space 32, the second internal space 46, and the first internal space 49 communicate with each other through a gap between the screw shaft 39 and the nut 41. The oil supply paths 34 and 36 can supply oil to the inside of the screw shaft 39 and the nut 41 so that the oil flows between the screw shaft 39 and the nut 41 that convert the rotational motion into a linear motion.

  Therefore, the heat dissipation of the feed screw mechanism 12 composed of the screw shaft 39 and the nut 41 that converts the rotational motion into a linear motion is improved by the circulation of the oil flowing inside.

  In the present embodiment, the first space 32 and the second internal space 46, particularly the screw shaft 39 and the nut 41, are divided by the end 41 a of the nut 41 and the screw shaft 39 disposed in the nut 41. As a result, oil can flow reliably between the screw shaft 39 and the nut 41 in the feed screw mechanism 12.

  The oil supply paths 34 and 36 are configured to connect the opening 34 a of the oil supply hole 34 to the first space 32 and connect the opening 36 a of the oil discharge hole 36 to the first internal space 49. Yes. As a result, oil supplied from the oil pump 35 to the oil supply paths 34 and 36 can circulate between the first space 32 and the second internal space 46 and the first internal space 49, so that the oil supply paths 34 and 36 The oil flowing through the oil can forcibly circulate between the screw shaft 39 and the nut 41 in the feed screw mechanism 12.

  In the present embodiment, the oil discharge hole 36 is formed as a through-hole penetrating the screw shaft 39, so that oil can be passed between the first space 32 and the second internal space 46 and the first internal space 49. The flowing oil supply path can be formed relatively simply.

  The oil discharge hole 36 is preferably penetrated so as to open at an end 39 extending toward the control shaft 12 side.

  In general, in the joint member 99, a relatively large tensile force acts on the control shaft 12 by the operation of the intake valve 6 that changes the lift amount by the control shaft 12. Each time the tensile force is generated, the end 12j of the control shaft 12, the end 39j of the screw shaft 39, and the joint member 99 that connects the ends 12j, 39j are added. The end 39j of the screw shaft 39 and the joint member 99 are easily worn.

  On the other hand, in this embodiment, the oil flowing through the hydraulic oil supply paths 34 and 36 can be guided to both end portions 12j and 39j and the joint member 99 that connects the end portions 12j and 39j. Therefore, it is possible to prevent wear of the end 12j of the control shaft 12, the end 39j of the screw shaft 39, and the joint member 99.

  Furthermore, in the present embodiment, there is an inner ring that is attached to the nut 41, and between the radial bearing 23 that rotatably supports the nut 41, the first space 32, and the radial bearing 23 on the second space 33 side. And an oil seal 24 that seals the oil guided to the first space 32. Further, the oil supply paths 24 and 36 are configured to introduce oil into the first space 32 and discharge the oil from the first internal space 49.

  In general, when the oil seal 24 is provided between the first space 32 and the radial bearing 23, it is necessary to minimize the flow rate of oil supplied from the hydraulic oil supply paths 34 and 36 due to the pressure resistance of the oil seal 24. .

  On the other hand, in the present embodiment, the oil supply paths 34 and 36 introduce oil into the first space 32 and discharge oil from the first internal space 49, so that the first space 32 is adjusted by adjusting the oil flow rate. It is easy to make the oil pressure below the withstand pressure.

  Furthermore, in this embodiment, the motor part 26 arrange | positioned in the 2nd space 33 and the lid 42 which isolates the 1st internal space 49 are provided, and the lid 42 is mounted | worn with the edge part 41b of the nut 41. FIG. .

  According to this, between the nut 41 that needs to be cooled and the screw shaft 39 is cooled by oil, the inside of the motor unit 26 is hermetically sealed by the lid 42, and the motor unit 26 that needs to be cooled is interposed via the lid 42. It can be cooled with oil.

(Other embodiments)
As mentioned above, although one Embodiment of this invention was described, this invention is limited to this embodiment and is not interpreted and can be applied to various embodiment in the range which does not deviate from the summary.

  (1) For example, in the present embodiment described above, the feed screw mechanism 21 in which the rotary shaft 38 and the screw shaft 39 are directly meshed with each other is used, but the rotary shaft and the screw shaft are connected via gears, balls, or the like. A mechanism that is indirectly linked may be used.

  (2) In the present embodiment described above, the screw shaft 39 and the control shaft 12 are coaxially connected to each other. However, the screw shaft 39 may be eccentrically connected to the control shaft 12.

  (3) In the present embodiment described above, in the oil lubrication paths 34 and 36, the oil discharge hole 36 is connected to the first internal space 49, and the oil supply hole 34 is connected to the first space 32 and the second internal space 46. It was explained in the configuration of connecting. Not limited to this, an oil supply hole for supplying oil to the first internal space 49 may be connected, and an oil discharge hole for discharging oil to the first space 32 and the second internal space 46 may be connected.

  (4) Furthermore, in the present embodiment described above, the first internal space 49 is separated from the other spaces 33 by the lid 42 integrated with the rotation shaft 38. The lid 42 is not limited to having the partition wall portion 44a, the fitting portion 44b, and the sleeve portion 44c, but may be any partition member having at least the partition wall portion 44a.

  (5) Furthermore, in the present embodiment described above, the internal spaces 46 and 49 that make the oil liquid-tight are defined by the both ends 41 a and 41 b of the rotating shaft 38 and the screw shaft 39. In the feed screw mechanism 12 including the screw shaft 39 and the rotation shaft 38 (nut 41) that convert the rotational motion into a linear motion, the first internal space 49 is the counter-control shaft of the rotation shaft 38. Any structure may be used as long as it is provided in the first peripheral area on the 12 side and the first internal space 46 is provided in the second peripheral area on the control shaft 12 side of the rotating shaft 38.

  (6) Further, in the present embodiment described above, it has been described that the axial contact ball bearing is provided as the thrust bearing 22. However, the present invention is not limited to this, and the thrust bearing 22 may not be installed.

  (7) Furthermore, in the present embodiment described above, it has been described that an IPM brushless motor in which the permanent magnet 68 is embedded in the rotary rotor 65 is used as the motor unit 26. However, the present invention is not limited to this, and various known motors such as a DC motor can be used as the motor unit.

  (8) Furthermore, in the present embodiment described above, the change mechanism 8 combined with the actuator 10 may be any mechanism that changes the valve lift amount according to the position of the control shaft 12 in the axial direction. A configuration other than that described in FIG. 2 may be used. Alternatively, a change mechanism that urges the screw shaft toward the current-carrying portion in the axial direction by a valve reaction force transmitted to the control shaft 12 may be used in combination with this change mechanism and an actuator. Furthermore, a change mechanism 8 that changes the lift amount of the exhaust valve of the engine may be used in combination with the actuator 10.

  (9) Furthermore, in the present embodiment described above, the change mechanism 8 that changes the lift amount of the intake valve 6 is used in combination with the actuator 10, but the present invention is not limited to this, and the lift valve of the exhaust valve can be used as a control target valve. A change mechanism that changes the amount may be combined with the actuator.

It is a fragmentary sectional view showing an actuator of a valve lift control device by one embodiment of the present invention. 2A and 2B are schematic views showing a valve lift control device according to an embodiment of the present invention, in which FIG. 2A is an axial partial sectional view of a control shaft, and FIG. 2B is a radial sectional view. It is sectional drawing which shows the actuator of the valve lift control apparatus by one Embodiment of this invention.

Explanation of symbols

2 Valve lift control device 2 Engine (internal combustion engine)
6 Intake valve (Controlled valve)
8 Changing Mechanism 10 Actuator 12 Control Shaft 12j End 20 Body Case 21 Feed Screw Mechanism 22 Thrust Bearing 23 Radial Bearing (Rolling Bearing)
24 Oil seal 25 Displacement restricting portion 26 Motor portion 27 Magnet portion 28 Sensor portion 29 Energizing portion 32 First space (second circumferential region)
33 Second space 34 Oil supply hole 34a Inlet port (opening, second guide port 35 Oil pump 36 Oil discharge hole (through hole)
36a Inlet (opening, first guide port)
38 Rotating shaft 39 Screw shaft 39j End 41 Nut 41a One end (End)
41b The other end (end)
42 Lid (partition wall member)
44a Partition part 43 Circlip (locking member)
46 2nd interior space (2nd circumference)
49 1st interior space (1st circumference)
56 Inner ring 57 Outer ring 60 Stopper 61 Wave washer (elastic member)
64 Locking portion 65 Rotating rotor 66 Stator 74 Magnet holder 75 Permanent magnet 76 Hall element 80 Circuit case 81 Drive circuit 90 Control circuit 99 Joint member

Claims (7)

Used in a valve lift control device for controlling the lift amount of at least one of the intake valve and the exhaust valve of the internal combustion engine,
In an actuator for a valve lift control device that linearly drives the control shaft of a changing mechanism that changes the lift amount according to the axial position of the control shaft,
A feed screw that has a screw shaft that linearly moves in the axial direction together with the control shaft, and a rotary shaft that is arranged coaxially with the screw shaft and that rotates and converts the rotary motion of the rotary shaft into linear motion of the screw shaft Mechanism,
A motor unit that is provided on the counter-control shaft side of the rotating shaft and that rotates the rotating shaft by energization;
A hydraulic fluid supply path through which hydraulic fluid flows between a first circumferential region on the counter-control shaft side of the rotating shaft and a second circumferential region on the control shaft side of the rotating shaft;
An actuator for a valve lift control device. The screw shaft is disposed within the rotating shaft;
2. The actuator for a valve lift control device according to claim 1, wherein the first peripheral region is partitioned by the rotating shaft and the screw shaft disposed in the rotating shaft.   The hydraulic oil supply path includes a first guide port that guides hydraulic oil to the first peripheral region, and a second guide port that guides hydraulic oil to the second peripheral region, and the first peripheral region. 3. The valve lift control device actuator according to claim 1, wherein the hydraulic oil circulates in the second peripheral region. 4. The screw shaft includes a through hole that opens in the screw shaft toward the first circumferential region side,
The valve lift control device actuator according to claim 3, wherein the opening forms the first guide opening. A joint member that rotatably connects the opposite ends of the screw shaft and the control shaft;
The actuator for a valve lift control device according to claim 4, wherein the through hole extends so as to open at the end of the screw shaft. A rolling bearing having an inner ring attached to the rotating shaft, and rotatably supporting the rotating shaft;
An oil seal that is disposed between the second peripheral region and the rolling bearing and seals the hydraulic fluid guided to the second peripheral region;
6. The hydraulic oil supply path according to claim 1, wherein the hydraulic oil is introduced from the second peripheral area and discharged from the first peripheral area. The actuator for a valve lift control device according to the item. A partition member separating the motor part and the first peripheral region;
The valve partition control actuator according to any one of claims 1 to 6, wherein the partition member is attached to the rotating shaft.

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