JP2009008003A - Valve lift actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly durable valve lift actuator. <P>SOLUTION: A male screw part 340 formed on a linear motion shaft 34 which linearly moving together with a control shaft 12 for changing a valve lift amount is screwed, through ball members 36, with a female screw part 320 formed in the inner peripheral part 32 of a bottomed cylindrical rotary body 31 which is rotatingly driven by an electric motor 50. An oil seal 40 is disposed in the boundary portion between a first storage chamber 22 into which the first end part 311 of the rotary body 31 is opened and a second storage chamber 23 for storing the second end part 312 of the rotary body 31 on the closing side and the electric motor 50. The linear motion shaft 34 comprises: a flange part 344 slidably supported on the inner peripheral part 32 of the rotary body 31 on the first end part 311 side more than the female screw part 320; and a communication hole part 346 allowing the female screw part 320 side to communicate with the first storage chamber 22 side with the flange part 344 interposed therebetween. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a valve lift control device that controls a valve lift amount of a control target valve that is at least one of an intake valve and an exhaust valve of an internal combustion engine, and a valve that linearly drives a control shaft for changing the valve lift amount. The present invention relates to a lift actuator.

  2. Description of the Related Art Conventionally, there has been known a valve lift actuator that applies a large driving shaft force to a control shaft by using a rotation / linear motion conversion mechanism in which the linear motion shaft moves linearly in the axial direction together with the control shaft according to the rotation of the rotating body. ing. As a kind of such a valve lift actuator, Patent Document 1 discloses that a rotating body of a rotation / linear motion conversion mechanism is rotationally driven by an electric motor.

  Specifically, in the valve lift actuator disclosed in Patent Document 1, a first storage chamber and a second storage chamber that are adjacent to each other are formed inside the main body housing, and a seal member that seals between the main body housing and the rotating body is stored therein. Located at the boundary of the chamber. Here, the rotating body is formed in a bottomed cylindrical shape having a first end opened in the first housing chamber and a second end closed in the second housing chamber, and a linear motion shaft is formed inside the rotating body. Is screwed to the rotating body. An electric motor that rotates the rotating body by energization is accommodated in the second accommodation chamber.

Under such a configuration, the lubricating oil supplied to the first housing chamber through the supply hole of the main body housing enters the inside of the rotating body that opens in the first housing chamber, so that the rotating body and the linear motion shaft A lubricating action and a cooling action are exerted on the screwed portion. On the other hand, the lubricating oil supplied to the first storage chamber is prevented from flowing into the second storage chamber by the sealing member, and the lubricating oil that has entered the rotary body is at the end of the rotary body on the second storage chamber side. The blockage prevents inflow into the second storage chamber. Therefore, it is possible to avoid a situation in which the electric motor housed in the second housing chamber is in contact with the lubricating oil and fails.
2006-214291

  By the way, in the valve lift actuator disclosed in Patent Document 1, the lubricant infiltrates from the end portion on the first storage chamber side into the inside of the rotary body, and toward the closed end portion on the second storage chamber side. Flows inside. Therefore, there is a possibility that the lubricating oil may stay in the rotating body. When the lubricating oil stays inside the rotating body in this way, foreign matter such as abrasion powder generated at the threaded portion of the rotating body and the linear motion shaft is difficult to be discharged from the inside of the rotating body, and there is a concern about a decrease in durability. The Further, the retention of the lubricating oil inside the rotating body hinders the heat radiation from the inside, and therefore, it is conceivable that the durability is lowered due to the deterioration of the lubricating oil.

  The present invention has been made in view of the problems described above, and an object thereof is to provide a highly durable valve lift actuator.

  According to a first aspect of the present invention, there is provided a valve lift control device for controlling a valve lift amount of a valve to be controlled which is at least one of an intake valve and an exhaust valve of an internal combustion engine, and a control shaft for changing the valve lift amount. A valve lift actuator that is linearly driven and includes a first storage chamber and a second storage chamber that are adjacent to each other, and a supply hole for supplying a lubricant to the first storage chamber and lubrication from the first storage chamber to the outside. A main body housing having a discharge hole for discharging the liquid, and a bottomed cylindrical shape in which the first end is opened in the first storage chamber and the second end is closed in the second storage chamber; A rotary body having a peripheral portion, a male screw portion that is screwed with the female screw portion, a linear movement shaft that moves linearly in the axial direction together with the control shaft according to the rotation of the rotary body, a first storage chamber, and a second storage chamber At the boundary of And a sealing member that seals between the main body housing and the rotating body, and an electric motor that is housed in the second storage chamber and that rotates the rotating body when energized. A flange portion that is slidably supported by the inner peripheral portion of the rotating body on one end portion side, and a communication hole portion that communicates the female screw portion side and the first storage chamber side with the flange portion interposed therebetween. .

  As described above, according to the first aspect of the present invention, the inner peripheral portion of the bottomed cylindrical rotating body whose second end portion on the second storage chamber side is closed is screwed with the male screw portion of the linear motion shaft. The flange portion of the linear motion shaft is slidably supported on the first end portion side of the female screw portion. Therefore, when the linear motion shaft linearly moves in the axial direction from the second end side toward the first end side, the volume of the space inside the rotating body increases between the flange portion and the second end portion. Here, the communicating hole portion of the linear motion shaft communicates both sides sandwiching the flange portion, that is, the first accommodating chamber side where the first end portion of the rotating body is opened and the female screw portion side. Therefore, the lubricating liquid supplied to the first storage chamber through the supply hole portion of the main body housing is sucked into the space through the communication hole portion due to the increase in the volume of the space between the flange portion and the second end portion. As a result, the lubricating liquid can be reliably supplied between the female screw portion and the male screw portion to exhibit a lubricating action and a cooling action.

  On the other hand, when the linear movement shaft moves linearly in the axial direction from the first end side to the second end side, the volume of the space inside the rotating body decreases between the flange portion and the second end portion, and the space The lubricant is discharged into the first storage chamber through the communication hole. Here, the lubricating liquid discharged to the first storage chamber is discharged to the outside through the discharge hole portion of the main body housing. Therefore, the lubricant containing foreign matter such as wear powder is prevented from staying inside the rotating body, and the lubricating liquid is efficiently discharged from the inside of the rotating body to the first storage chamber and further to the outside of the main body housing. It can be done. Furthermore, the heat generated inside the rotating body can be released together with the lubricating liquid, and deterioration of the lubricating liquid inside the rotating body can be avoided.

  In addition, the lubricant supplied to the first storage chamber is prevented from flowing into the second storage chamber by the seal member at the boundary between the first and second storage chambers, and is sucked into the rotating body through the communication hole. In addition, the lubricating liquid is prevented from flowing into the second storage chamber by closing the second end of the rotating body. Therefore, the electric motor accommodated in the second accommodating chamber can be protected from the lubricating liquid.

  As described above, according to the first aspect of the present invention, the lubricity and the cooling performance inside the rotating body by the lubricating liquid are ensured over a long period of time, and the failure of the electric motor is avoided. Can be realized.

  According to invention of Claim 2, a communicating hole part penetrates a flange part to an axial direction. According to this, the flow resistance of the lubricating fluid that flows in the communication hole portion by linear movement of the linear motion shaft in the axial direction becomes small in the communication hole portion that penetrates the flange portion in the axial direction. Accordingly, the suction and discharge efficiency of the lubricating liquid according to the linear movement of the linear motion shaft can be increased.

  The invention according to claim 3 is a valve lift actuator installed so that the axial direction of the linear movement shaft substantially coincides with the horizontal direction on a horizontal plane, and the flange portion is cut at the outermost portion at the lowermost portion. The communication hole is formed between the notch on the outer peripheral portion of the flange portion and the inner peripheral portion of the rotating body. Thus, according to the communication hole portion formed between the notch in the lowermost portion of the outer peripheral portion of the flange portion and the inner peripheral portion of the rotating body that slide-supports the flange portion, It is possible to reliably discharge the lubricating liquid at the lowermost part of the peripheral portion.

  According to the fourth aspect of the present invention, the linear movement shaft has a protruding portion that protrudes from the end surface where the communication hole portion opens in the flange portion toward the first housing chamber, and the main body housing is formed from the opposite side of the flange portion. It has a stopper portion that stops the movement of the linear motion shaft by coming into contact with the protruding portion. According to this, the flange portion that changes the space volume inside the rotating body for discharging the lubricating liquid and foreign matter is also used to stop the movement of the linear motion shaft, and the valve lift is achieved while simplifying the configuration. It is possible to make the adjustment range of the amount appropriate for the internal combustion engine.

  According to the fifth aspect of the present invention, the linear motion shaft is slidably supported by the inner peripheral portion of the rotating body on the second end side of the first through hole portion as the communication hole portion and the female screw portion. And a second communicating hole portion that communicates the female screw portion side and the second end portion side with the sliding end portion interposed therebetween. As described above, in the invention described in claim 5, the inner peripheral portion of the bottomed cylindrical rotating body whose second end portion is closed slides the linear motion shaft closer to the second end portion than the female screw portion. The end is slidably supported. Therefore, when the linear movement shaft linearly moves in the axial direction from the first end portion side to the second end portion side, the volume of the space inside the rotating body decreases between the second end portion and the sliding end portion. Here, the second communication hole portion of the linear motion shaft communicates both sides sandwiching the sliding end portion, that is, the second end portion side and the female screw portion side. Therefore, the lubricating liquid leaked from the internal threaded portion side of the sliding end portion to the space on the second end side of the sliding end portion through the sliding interface of the rotating body and the sliding end portion, due to the volume reduction of the space, It can be returned to the original through the second communication hole. According to this, the linear movement of the linear motion shaft from the first end portion side to the second end portion side can be suppressed from being inhibited by the lubricating liquid on the second end portion side of the sliding end portion.

  According to the invention described in claim 6, the female screw portion and the male screw portion are indirectly screwed together via the ball member. As a result, the lubricating liquid easily flows in the axial direction through the gap around the ball member between the female screw portion and the male screw portion, so that the lubricity and cooling performance inside the rotating body are improved.

  The female screw portion and the male screw portion may be indirectly screwed via planetary gears other than the ball member, for example, or may be directly screwed as in the invention according to claim 7. You may do.

  Hereinafter, a plurality of embodiments of the present invention will be described with reference to the drawings. In addition, the overlapping description is abbreviate | omitted by attaching | subjecting the same code | symbol to the corresponding component in each embodiment.

(First embodiment)
FIG. 2 shows a valve lift control device 1 including a valve lift actuator 10 according to the first embodiment of the present invention. The valve lift control device 1 is mounted on a vehicle and controls the valve lift amount using the intake valve 3 of the internal combustion engine 2 as a control target valve. The valve lift control device 1 includes a change mechanism 4, a valve lift actuator 10, and the like.

  First, the changing mechanism 4 will be described. The change mechanism 4 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 internal combustion engine 2. Specifically, the changing mechanism 4 includes a control shaft 12 connected to the linear motion shaft 34 of the valve lift actuator 10. The slider gear 14 that moves linearly with the control shaft 12 is helically spline-fitted to the input portion 15 and the swing cam 16, and the input portion 15 and the swing shaft 14 are moved according to the axial movement position of the control shaft 12. The relative phase difference between the moving cams 16 changes. Here, the input unit 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 3. The rocking angle of the rocker arm 19 changes according to the relative phase difference between the sixteen. Therefore, in the change mechanism 4, the valve lift amount of the intake valve 3 changes according to the movement position of the control shaft 12 that is linearly driven by the valve lift actuator 10, and thereby the valve characteristics such as the operating angle and the maximum valve lift amount are changed. Will be adjusted. In this embodiment, the valve spring reaction force transmitted from the intake valve 3 to the control shaft 12 acts on the control shaft 12 as an axial force directed to the side opposite to the valve lift actuator 10.

  Next, the valve lift actuator 10 will be described. As shown in FIG. 3, the valve lift actuator 10 includes a main body housing 20, a rotation / linear motion conversion mechanism 30, an oil seal 40, an electric motor 50, and an energization circuit unit 60.

  The main body housing 20 is made of metal, and has a stepped cylindrical shape with a bottom. The main body housing 20 is fixed to the internal combustion engine 2 in a state where the bottom wall 21 side is fitted to the fixed wall 7 of the cylinder head 6 of the internal combustion engine 2. The main body housing 20 has a first storage chamber 22 and a second storage chamber 23 adjacent to each other. Here, the first storage chamber 22 is located closer to the bottom wall 21 than the second storage chamber 23, that is, to the internal combustion engine 2 side.

  The rotation / linear motion converting mechanism 30 is a ball screw mechanism in which a rotating body 31 and a linear motion shaft 34 are indirectly screwed via a plurality of ball members 36.

  The rotating body 31 is a metal rotating nut having a bottomed stepped cylindrical shape as a whole, and is accommodated in the accommodating chambers 22 and 23 in a form straddling the first accommodating chamber 22 and the second accommodating chamber 23. Yes. Under such accommodation, one end 311 in the axial direction of the rotating body 31 constitutes a first end 311 that opens in the first housing chamber 22, while the other end 312 in the axial direction of the rotating body 31 is A second end 312 that is closed in the second storage chamber 23 is configured. In the inner peripheral portion 32 of the rotating body 31, a female screw portion 320 is provided at an intermediate portion in the axial direction. The female screw portion 320 forms a female screw groove 320a that opens toward the radially inner side of the rotating body 31 and extends spirally. An intermediate portion in the axial direction in the outer peripheral portion of the rotating body 31 is supported from the outer peripheral side by a radial bearing 24 provided in the main body housing 20. Thereby, the rotating body 31 is rotatable to both sides in the circumferential direction.

  The linear motion shaft 34 is a metal screw shaft having a round bar shape as a whole, and penetrates the bottom wall portion 21 of the main body housing 20 so as to be linearly movable in the axial direction. In the linear motion shaft 34, the one end portion 341 in the axial direction and the male screw portion 340 provided on the other end portion 342 side than the end portion 341 are inserted concentrically into the rotating body 31. Here, the male screw portion 340 forms a male screw groove 340a that opens outward in the radial direction of the linear movement shaft 34 and extends spirally, and between the male screw groove 340a and the female screw groove 320a of the female screw portion 320. A plurality of metal ball members 36 are interposed so as to roll freely. As described above, in the rotation / linear motion conversion mechanism 30 in which the male screw portion 340 and the female screw portion 320 are screwed together via the ball member 36, the linear movement position of the linear motion shaft 34 in the axial direction is the circumference of the rotating body 31. It changes according to the rotational position of the direction. That is, the rotation / linear motion conversion mechanism 30 converts the rotational motion of the rotating body 31 into the linear motion of the linear motion shaft 34.

  An end 342 of the linear motion shaft 34 on the side inserted into the cylinder head 6 is coaxially connected to the control shaft 12 of the change mechanism 4 via a coupling 35. As a result, the linear movement shaft 34 can move linearly in the axial direction together with the control shaft 12, and the axial force resulting from the valve spring reaction force of the intake valve 3 is transmitted from the control shaft 12 side. Yes.

  The oil seal 40 as a “seal member” is disposed at the boundary between the first storage chamber 22 and the second storage chamber 23 on the outer peripheral side of the rotating body 31. Under such an arrangement, the oil seal 40 seals between the main body housing 20 and the rotating body 31 that form the storage chambers 22 and 23 in a state in which the space between the first storage chamber 22 and the second storage chamber 23 is liquid-tightly partitioned. is doing.

  The electric motor 50 is a brushless motor that is a combination of a motor rotor 51 and a motor stator 52, and is accommodated in the second accommodation chamber 23.

  The motor rotor 51 has a rotor core 53, a drive magnet 54, a sensor magnet 55, and a magnetic holder 56. The rotor core 53 is made of a magnetic material and has a cylindrical shape. The rotor core 53 is externally fitted concentrically to the rotating body 31 so that the motor rotor 51 can rotate with the rotating body 31 to both sides in the circumferential direction. The drive magnets 54 are made of permanent magnets and are mounted on the rotor core 53 at a plurality of locations that are equally spaced in the circumferential direction. The drive magnets 54 adjacent to each other in the circumferential direction of the rotor core 53 form opposite magnetic poles on the outer peripheral surface side of the rotor core 53. The sensor magnet 55 is made of a permanent magnet and has an annular shape. The sensor magnet 55 is coaxially fixed to the rotor core 53 via the magnetic holder 56, so that it can rotate together with the rotating body 31. The sensor magnet 55 is configured such that a plurality of magnetic poles formed on one end surface side in the axial direction conflict with each other adjacent in the circumferential direction.

  The motor stator 52 has a stator core 57 and a stator coil 58. The stator core 57 is made of a magnetic material and has an annular block shape. The stator core 57 is concentrically disposed on the outer peripheral side of the motor rotor 51 and is fixed to the main body housing 20. The stator core 57 is provided with a plurality of tooth portions 59 protruding to the inner peripheral side. The stator coils 58 are individually wound around the teeth portions 59.

  The energization circuit unit 60 includes a driver housing 62, a motor driver 70, and a control circuit 80.

  The driver housing 62 is a combination of three members 64, 65 and 66. Here, the base member 64 is bolted to the opening side end of the main body housing 20. The intermediate member 65 is bolted to the opening side end of the main body housing 20 in such a form that the base member 64 is sandwiched between the intermediate member 65 and the main body housing 20. The cover member 66 is fitted and fixed to the intermediate member 65 from the side opposite to the base member 64. As described above, the driver housing 62 is disposed adjacent to the second housing chamber 23 on the opposite side of the first housing chamber 22 to form a driver chamber 67 that houses the motor driver 70.

  The motor driver 70 includes, for example, a bridge circuit and a driving IC, and is electrically connected to each stator coil 58 of the motor stator 52 via a harness 71 that passes through the intermediate member 65 and the base member 64. The motor driver 70 energizes each stator coil 58 to excite the coils 58 in a predetermined order, thereby generating a rotating magnetic field that acts on the motor rotor 51. Accordingly, the rotating body 31 is rotated together with the motor rotor 51 in the direction of the magnetic field generated by each stator coil 58, and the linear motion shaft 34 is linearly driven accordingly.

  The motor driver 70 is provided with a plurality of magnetic detection elements 72 exposed into the second storage chamber 23 through an inner peripheral hole 68 that penetrates the base member 64. Each magnetic detection element 72 is, for example, a Hall element, and is disposed so as to face the sensor magnet 55 of the motor rotor 51 in the axial direction. Each magnetic detection element 72 detects the rotational position of the rotating body 31 (motor rotor 51) based on the magnetic action received from the sensor magnet 55. Here, the motor driver 70 is electrically connected to the control circuit 80, and gives the detected rotational position of the rotating body 31 to the control circuit 80.

  In this embodiment, the control circuit 80 also serves as a control circuit for the internal combustion engine, and is disposed outside the housings 20 and 62. The control circuit 80 calculates the linear movement position of the linear motion shaft 34 (control shaft 12) based on the rotational position of the rotating body 31 given from the motor driver 70. Further, the control circuit 80 estimates the actual valve lift amount of the intake valve 3 from the calculated linear movement position of the linear motion shaft 34, and issues a feedback control command based on the difference between the actual valve lift amount and the target valve lift amount to the motor driver. To 70. By energizing each stator coil 58 from the motor driver 70 in accordance with this control command, the control shaft 12 is linearly driven together with the linear motion shaft 34 to achieve the target valve lift amount. Note that the target valve lift amount is set by the control circuit 80 based on, for example, the vehicle operating conditions such as the rotational speed of the internal combustion engine and the accelerator opening.

  Next, the characteristic configuration of the first embodiment will be described in detail.

  As shown in FIG. 3, the cylinder head 6 of the internal combustion engine 2 forms a conveyance path 90. The conveyance path 90 is connected to the oil pump 8 of the internal combustion engine 2, and extends to the fitting hole portion 91 in which the main body housing 20 is fitted in the fixed wall portion 7. Here, the oil pump 8 is a mechanical pump that is driven by the rotational output of the internal combustion engine 2. Therefore, the lubricating oil discharged as “lubricating liquid” from the oil pump 8 is always supplied to the main body housing 20 through the conveyance path 90 during operation of the internal combustion engine 2.

  The cylinder head 6 further has a discharge chamber 92 on the opposite side of the main body housing 20 with the fixed wall portion 7 interposed therebetween. The discharge chamber 92 is connected to the oil oil pan 9 of the oil pump 8, and the lubricating oil discharged from the inside of the main body housing 20 to the external discharge chamber 92 is returned to the oil pump 8 as will be described later. Yes.

  In the stepped cylindrical main body housing 20 shown in FIGS. 1 and 4, the first storage chamber 22 is formed on the inner peripheral side and is fitted to the fitting hole 91 and fixed to the fixed wall portion 7. A supply hole portion 96 is formed in the peripheral wall portion 94. The supply hole 96 is formed in a cylindrical hole shape that radially penetrates between the outer peripheral surfaces of the peripheral wall portion 94, and is opened to the inner peripheral surface of the first storage chamber 22 and the fitting hole portion 91. It communicates with the opening 901 of the path 90. As a result, the lubricating oil in the conveyance path 90 is supplied to the first storage chamber 22 through the supply hole 96.

  A discharge hole 98 is formed in the bottom wall 21 that closes one end of the peripheral wall 94 in the main body housing 20. The discharge hole 98 is formed in a cylindrical hole shape that penetrates the outer surface of the bottom wall portion 21 in the axial direction on the outer peripheral side of the linear movement shaft 34, and is formed between the first storage chamber 22 and the discharge chamber 92. Is communicated. As a result, the lubricating oil in the first storage chamber 22 is discharged to the discharge chamber 92 through the discharge hole 98.

  In the main body housing 20, a metal stopper member 25 that is attached to the bottom wall portion 21 and through which the linear motion shaft 34 penetrates forms a stopper portion 26. The stopper portion 26 is a flat surface that is substantially perpendicular to the central axis of the linear motion shaft 34 and faces the first storage chamber 22.

  In the main body housing 20 having the above features, in this embodiment, the axial direction of the linear motion shaft 34 that penetrates the bottom wall portion 21 and the stopper member 25 (the left-right direction in FIGS. 1, 3, and 4) is on the horizontal plane. It is installed so as to substantially coincide with the horizontal direction.

  In the linear motion shaft 34 shown in FIGS. 1 and 4, a flange portion 344 is provided on the end 342 side of the axially threaded portion 340. As shown in FIGS. 1, 4, and 5, the flange portion 344 has a flat plate shape in which a circular outer peripheral portion 345 that is substantially perpendicular to the central axis of the linear motion shaft 34 is cut out at the lowermost portion. As shown in FIGS. 1 and 4, the linear motion shaft 34 is provided with a protruding portion 343 that protrudes from the end surface 344 a of the flange portion 344 toward the end portion 342. The protruding portion 343 has a columnar shape having a smaller diameter than the flange portion 344 and has a tip surface 343 a substantially parallel to the stopper portion 26. Therefore, when the linear movement shaft 34 linearly moves in the axial direction from the second end 312 side toward the first end 311 side, the tip end surface 343a of the protruding portion 343 faces the stopper portion 26 on the side opposite to the flange portion 344. By the contact, the linear movement is stopped, and the adjustment range of the valve lift amount is limited to an appropriate range.

  The large diameter portion 321 constituting the first end portion 311 in the inner peripheral portion 32 of the rotating body 31 is slidably fitted to the outer peripheral portion 345 of the flange portion 344 of the linear motion shaft 34. As a result, as shown in FIGS. 1, 4, and 5, the inner peripheral portion 32 of the rotating body 31 supports the flange portion 344 on the first end portion 311 side with respect to the female screw portion 320 and the outer peripheral portion 345 of the flange portion 344. A first series of through holes 346 are formed between the notches 345a. Then, as shown in FIG. 4, the first series of through-hole portions 346 formed in this way has a shape that penetrates the lowermost portion of the flange portion 344 in the axial direction and opens to the outer end surface 344 a of the protruding portion 343. It becomes. Accordingly, the first series through-hole portion 346 of the present embodiment communicates the both sides sandwiching the flange portion 344 in the axial direction, that is, the first storage chamber 22 side where the first end portion 311 opens and the female screw portion 320 side. It is. In the present embodiment, the discharge hole portion 98 is provided at the lowermost portion of the bottom wall portion 21 of the main body housing 20 corresponding to the first series of through-hole portions 346.

  As shown in FIGS. 1 and 4, the small diameter portion 322 constituting the second end portion 312 in the inner peripheral portion 32 of the rotating body 31 is slidably fitted to the outer peripheral portion 347 of the end portion 341 of the linear motion shaft 34. is doing. Thereby, the inner peripheral portion 32 of the rotating body 31 supports the end portion 341 on the second end portion 312 side with respect to the female screw portion 320. Further, the end portion 341 supported by the inner peripheral portion 32 of the rotating body 31 in this manner is on both sides sandwiching the end portion 341 in the axial direction, that is, the closed bottom portion 33 constituting the second end portion 312 in the rotating body 31. A second communication hole portion 348 is provided in an L shape so that the side communicates with the female screw portion 320 side. Therefore, in the present embodiment, the end portion 341 that forms the second communication hole portion 348 corresponds to the “sliding end portion” recited in the claims, and hereinafter, the end portion 341 is referred to as the sliding end portion. The part 341 is referred to.

  Due to the above characteristics, the first space 313 forms the second end 312 between the flange portion 344 and the second end 312 that sandwich the screwed portions of the screw portions 320 and 340 inside the rotating body 31. A second space 314 is defined between the closed bottom 33 and the sliding end 341.

  Next, the characteristic operation of the first embodiment will be described in detail.

  In the valve lift actuator 10, during operation of the internal combustion engine 2, the lubricating oil from the conveyance path 90 is supplied to the first storage chamber 22 inside the main body housing 20 through the supply hole portion 96. When the linear motion shaft 34 is linearly driven in the axial direction from the second end 312 side toward the first end 311 side under the supply of such lubricating oil, the volume of the first space 313 increases as shown in FIG. To do. As a result, the internal pressure of the first space 313 decreases, and the lubricating oil supplied to the first storage chamber 22 is sucked into the first space 313 through the first series of through holes 346.

  At this time, the flow resistance of the lubricating oil becomes as small as possible in the first through-hole portion 346 that penetrates the flange portion 344 in the axial direction in which the linear motion shaft 34 moves. Increases efficiency. Furthermore, between the threaded portions 320 and 340 of the first space 313, the lubricating oil easily flows in the axial direction through the gap around the ball member 36. Therefore, the lubricating oil that has entered the first space 313 by the suction action can be reliably supplied between the screw portions 320 and 340, and the lubricating action and the cooling action can be exhibited.

  As shown in FIG. 5, the flange portion 344 of the present embodiment has an air vent hole portion 349 that passes through the flange portion 344 in the axial direction above the center axis of the linear motion shaft 34. It is provided separately from the part 346. As a result, when the lubricating oil supplied to the first storage chamber 22 immediately after starting the internal combustion engine 2 enters the first space 313 through the first through-hole portion 346, the air accumulated in the first space 313 is collected. Can be discharged from the upper air vent hole 349 to promote the oil intrusion.

  On the other hand, when the linear motion shaft 34 linearly moves in the axial direction from the first end portion 311 side to the second end portion 312 side, the volume of the first space 313 decreases as shown in FIG. As a result, the internal pressure of the first space 313 increases, and the lubricating oil that enters the first space 313 is discharged to the first storage chamber 22 side through the first through-hole portion 346.

  At this time, according to the first through-hole portion 346 configured to reduce the flow resistance of the lubricating oil as much as possible, the discharge efficiency of the lubricating oil is increased. Further, according to the first series of through-hole portions 346 provided at the lowermost portion of the outer peripheral portion 345 of the flange portion 344 fitted to the inner peripheral portion 32 of the rotating body 31, the lubrication at the lowermost portion of the inner peripheral portion 32 is performed. Even oil can be discharged.

  Thus, the lubricating oil discharged to the first storage chamber 22 is reliably discharged from the discharge hole portion 98 at a position corresponding to the first through-hole portion 346 to the discharge chamber 92 by the discharge pressure. become. Therefore, it is possible to prevent the lubricating oil containing foreign matter such as wear powder from staying inside the rotating body 31 and efficiently discharge the lubricating oil to the outside of the main body housing 20. Furthermore, the internal heat of the rotating body 31 can be released together with the lubricating oil, so that deterioration of the lubricating oil inside the rotating body 31 can be avoided.

  Further, the lubricating oil in the first space 313 is likely to leak into the second space 314 through the sliding interface between the inner peripheral portion 32 of the rotating body 31 and the sliding end portion 341 of the linear motion shaft 34. However, when the linear motion shaft 34 linearly moves in the axial direction from the first end portion 311 side to the second end portion 312 side, the volume of the second space 314 as shown in FIG. The leaked lubricating oil from 313 to the second space 314 is returned to the original first space 313 through the second communication hole 348. Therefore, the situation where the linear movement of the linear motion shaft 34 from the first end portion 311 side to the second end portion 312 side is hindered by the lubricating oil in the second space 314 can be suppressed.

  In addition, the lubricating oil supplied to the first storage chamber 22 is prevented from flowing into the second storage chamber 23 by the action of the oil seal 40. In addition, the lubricating oil that has entered the inside of the rotating body 31 is prevented from flowing into the second storage chamber 23 from the end portion 312 by closing the second end portion 312. Thus, the electric motor 50 housed in the second housing chamber 23 and the motor driver 70 (see FIG. 3) in which the magnetic detection element 72 is exposed in the second housing chamber 23 can be protected from the lubricating oil. .

  As described above, according to the first embodiment, the lubricity and cooling performance inside the rotating body 31 are ensured over a long period of time, and failure of the electric motor 50 and the motor driver 70 can be avoided. The valve lift amount can be controlled with high accuracy.

(Second embodiment)
As shown in FIG. 6, the second embodiment of the present invention is a modification of the first embodiment. The rotation / linear motion conversion mechanism 1030 of the second embodiment is a feed screw mechanism formed by directly screwing the rotating body 1031 and the linear motion shaft 1034.

  Specifically, an internal thread portion 1320 provided between the first and second end portions 311 and 312 in the inner peripheral portion 1032 of the rotating body 1031 forms a thread groove 1320a and a thread 1320b having a trapezoidal cross section. . Further, the external thread portion 1340 provided between the sliding end portion 341 and the flange portion 344 in the linear movement shaft 1034 forms a trapezoidal thread groove 1340a and a thread 1340b, and the thread groove 1340a and the thread thread. 1340b is screwed with the thread 1320b and the thread groove 1320a of the female thread portion 1320, respectively. Thereby, also in the rotation / linear motion conversion mechanism 1030 of this embodiment, the linear movement position of the linear motion shaft 1034 in the axial direction changes according to the rotational position of the rotating body 1031 in the circumferential direction.

  Also in the valve lift actuator 1010 of the second embodiment provided with such a rotation / linear motion conversion mechanism 1030, the same effects as those of the first embodiment are enjoyed by the functions of the flange portion 344 and the communication hole portions 346, 348 and the like. It can be done.

(Other embodiments)
Although a plurality of embodiments of the present invention have been described above, the present invention is not construed as being limited to these embodiments, and can be applied to various embodiments without departing from the scope of the present invention. .

  Specifically, for the first series of through holes 346, instead of or in addition to the lowermost part of the outer peripheral part 345 of the flange part 344, for example, other than the lowermost part of the outer peripheral part 345, the radial intermediate part of the flange part 344, etc. You may make it provide in. Further, the second communication hole 348 may not be provided.

  As the rotation / linear motion conversion mechanism 30, a mechanism in which the screw portions 320 and 340 are indirectly screwed via a rotating member such as a planetary gear instead of the ball member 36 may be employed. Further, in the rotation / linear motion conversion mechanisms 30 and 1030, the flange portion 344 may not be responsible for the stopper function of the linear motion shafts 34 and 1034. Furthermore, in the rotation / linear motion conversion mechanisms 30 and 1030, the linear motion shafts 34 and 1034 may be eccentrically connected to the control shaft 12.

  As the electric motor 50, a motor other than the brushless motor described above may be employed. Furthermore, in addition to the oil pump 8 of the internal combustion engine 2 composed of a mechanical pump, for example, a fluid supply source such as an electric pump that operates in accordance with the operation of the internal combustion engine 2 or in a timely manner may be used for supplying the lubricating oil (liquid). Good.

  As the change mechanism 4 in which the valve lift actuators 10 and 1010 are combined, if the valve lift amount can be changed according to the axial position of the control shaft 12, for example, the valve reaction force is on the valve lift actuator 10 side. You may employ | adopt what acts on the control shaft 12 as an axial force which goes to. Further, as the change mechanism 4, a mechanism that uses an exhaust valve as a control target valve, or a mechanism that controls both an intake valve and an exhaust valve may be adopted.

It is an expanded sectional view showing the characterizing portion of the valve lift actuator by a first embodiment of the present invention. It is the partial cross section schematic diagram (a) and the cross-sectional view (b) which show the valve lift control apparatus provided with the valve lift actuator by one Embodiment of this invention. It is sectional drawing which shows the valve lift actuator by 1st embodiment of this invention. It is an expanded sectional view which shows the operation state different from FIG. It is the VV sectional view taken on the line of FIG. It is a figure which shows the valve lift actuator by 2nd embodiment of this invention, Comprising: It is sectional drawing corresponding to FIG.

Explanation of symbols

1 valve lift control device, 2 internal combustion engine, 3 intake valve (valve to be controlled), 4 change mechanism, 6 cylinder head, 8 oil pump, 10, 1010 valve lift actuator, 12 control shaft, 20 body housing, 21 bottom wall , 22 1st storage chamber, 23 2nd storage chamber, 26 Stopper part, 30, 1030 Rotation linear motion conversion mechanism, 31, 1031 Rotating body, 32, 1032 Inner peripheral part, 33 Blocking bottom part, 34, 1034 Linear motion shaft, 36 ball member, 40 oil seal (seal member), 50 electric motor, 60 energization circuit part, 70 motor driver, 90 transport path, 901 opening part, 92 discharge chamber, 94 peripheral wall part, 96 supply hole part, 98 discharge hole part 311 first end, 312 second end, 313 first space, 314 second space, 320, 1320 female Threaded part, 320a Female thread groove, 321 Large diameter part, 322 Small diameter part, 340, 1340 Male thread part, 340a Male thread groove, 341 Sliding end part, 343 Projection part, 343a Tip face, 344 Flange part, 344a End face, 345 Outer part 346 First communication hole portion (communication hole portion), 347 outer peripheral portion, 348 second communication hole portion, 1320a, 1340a thread groove, 1320b, 1340b thread

Claims (7)

In a valve lift control device that controls a valve lift amount of a control target valve that is at least one of an intake valve and an exhaust valve of an internal combustion engine, a valve lift actuator that linearly drives a control shaft for changing the valve lift amount. And
A first storage chamber and a second storage chamber that are adjacent to each other are formed inside, a supply hole portion that supplies the lubricant to the first storage chamber, and a discharge hole portion that discharges the lubricant from the first storage chamber to the outside. A body housing having
A rotating body having a bottomed cylindrical shape in which the first end is opened in the first storage chamber and the second end is closed in the second storage chamber;
A linear motion shaft that has a male thread portion that is screwed with the female thread portion and linearly moves in the axial direction together with the control shaft according to the rotation of the rotating body;
A seal member disposed at a boundary portion between the first storage chamber and the second storage chamber and sealing between the main body housing and the rotating body;
An electric motor housed in the second housing chamber and driven to rotate the rotating body by energization,
The linear motion shaft includes a flange portion that is slidably supported by the inner peripheral portion on the first end side of the female screw portion, and the female screw portion side and the first storage chamber side across the flange portion. A valve lift actuator having a communication hole portion that communicates with the valve lift actuator.   The valve lift actuator according to claim 1, wherein the communication hole portion passes through the flange portion in an axial direction. A valve lift actuator installed on a horizontal plane so that an axial direction of the linear movement axis substantially coincides with a horizontal direction;
The flange portion has a shape in which the outer peripheral portion is cut out at the bottom,
3. The valve lift actuator according to claim 1, wherein the communication hole portion is formed between a cutout of the outer peripheral portion and the inner peripheral portion. The linear motion shaft has a protruding portion that protrudes from the end surface where the communication hole portion opens in the flange portion toward the first storage chamber,
The said main body housing has a stopper part which stops the movement of the said linear motion shaft by contact | abutting to the said protrusion part from the opposite side to the said flange part, The Claim 1 characterized by the above-mentioned. Valve lift actuator.   The linear motion shaft includes a first series of through holes as the communication hole, a sliding end that is slidably supported by the inner peripheral portion on the second end side with respect to the female screw portion, and the slide. 5. The valve lift actuator according to claim 1, further comprising a second communication hole portion that communicates the female screw portion side and the second end portion side with a moving end portion interposed therebetween.   The valve lift actuator according to any one of claims 1 to 5, wherein the female screw portion and the male screw portion are indirectly screwed through a ball member.   The valve lift actuator according to any one of claims 1 to 5, wherein the female screw part and the male screw part are directly screwed together.

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