JP4428709B2 - Actuator of valve lift control device - Google Patents

Description

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

Conventionally, in a valve lift control device, an actuator that linearly drives the control shaft has been widely used in order to change the lift amount of the control target valve in accordance with the axial position of the control shaft.
As an actuator for such a valve lift control device, an actuator has been proposed in which the rotational driving force of a motor is converted into a linear driving force through a speed reduction mechanism and a cam mechanism, and the linear driving force is transmitted to a control shaft (for example, a patent). Reference 1).

JP 2004-150332 A

  However, in the above-described actuator, in order to give a large linear driving force to the control shaft, a reduction mechanism and a cam mechanism must be used in combination. For this reason, there is a limit in reducing the overall physique, which may cause problems such as restrictions on the installation location.

  Therefore, the present inventor has conducted intensive research on an actuator using a feed screw mechanism that converts the rotational motion of the rotary shaft into the linear motion of the screw shaft instead of the speed reduction mechanism and the cam mechanism. In general, a feed screw mechanism can obtain a large linear driving force with a relatively simple configuration in which a rotating shaft and a screw shaft are directly or indirectly linked, so that compared to a combination of a speed reduction mechanism and a cam mechanism. Thus, the size of the actuator can be reduced.

However, as a result of further research by the present inventor, it has been found that the following problems arise when the lubricating fluid is supplied to the inside of the case housing the feed screw mechanism to lubricate the feed screw mechanism. The problem is that, for example, when lubricating oil for an internal combustion engine is used as a lubricating fluid, the lubricating oil that should be supplied to the internal combustion engine is reduced. In order to solve this problem, the amount of lubricating oil supplied to the actuator may be minimized, but since lubricating oil for internal combustion engines is generally used at high pressure, The supply amount of the lubricating oil must be finely processed to a diameter of 1 mm, for example, to reduce the supply amount. Such fine processing is time consuming and increases costs, which is not desirable.
The present invention has been made in view of these problems, and an object of the present invention is to provide an actuator of a valve lift control device that suppresses the supply of a lubricating fluid to the inside of a case that houses a feed screw mechanism.
Another object of the present invention is to provide an actuator for a valve lift control device that reduces costs.

According to the first aspect of the present invention, when the clearance is formed between the screw shaft of the feed screw mechanism and the rotation restricting portion that fits the outer peripheral wall of the screw shaft, the at least one uneven fitting of these elements is performed. A minute clearance can be easily formed by adjusting the size of the joint portion. Therefore, the formation of a minute clearance can be realized at a low cost, and the supply amount of the lubricating fluid can be suppressed by supplying the lubricating fluid to the inside of the housing case of the feed screw mechanism through the minute clearance. .
According to the first aspect of the present invention, the rotation regulation restricting portion that restricts the rotation of the screw shaft by fitting with the screw shaft also functions to form a clearance for supplying the lubricating fluid. Therefore, this also reduces the cost.
According to the first aspect of the present invention, since the screw shaft and the rotation restricting portion are spline-fitted with each other, the rotation of the screw shaft can be restricted while reducing the sliding resistance of the screw shaft with respect to the rotation restricting portion.
By the way, the spline teeth which are formed on the screw shaft and the rotation restricting portion and mesh with each other are in a state where the tooth surfaces are in close contact with each other when the feed screw mechanism is operated. For this reason, when a clearance for supplying the lubricating fluid is provided between the tooth surfaces of the spline teeth, the clearance may disappear during the operation of the feed screw mechanism. However, according to the first aspect of the present invention, the clearance for supplying the lubricating fluid is provided between the bottom surface and the top surface of the spline teeth that are formed on the screw shaft and the rotation restricting portion and mesh with each other. It does not disappear when the screw mechanism is activated. Therefore, the situation where the supply of the lubricating fluid through the clearance is hindered by the operation of the feed screw can be avoided.

According to the second aspect of the invention, the lubricating fluid for the internal combustion engine is supplied into the case through the clearance between the screw shaft and the rotation restricting portion. The influence on the supply amount of the lubricating fluid is reduced.
Note that the lubricating fluid supplied to the inside of the case through the clearance between the screw shaft and the rotation restricting portion may be different from the lubricating fluid for the internal combustion engine.

According to the invention described in claim 3 , since the supply amount of the lubricating fluid to the inside of the case can be suppressed by the clearance between the screw shaft and the rotation restricting portion, the lubricating fluid is supplied to the clearance from the outside of the case. There is no need to finely form the supply path. Therefore, it is possible to prevent an increase in cost due to the formation of the supply path.
According to the fourth aspect of the present invention, since the lubricating fluid supplied to the inside of the case is discharged to the outside of the case through the discharge path, a lubricating fluid circulation system can be constructed. In addition, since the discharge path does not need to be formed finely, the cost is not increased.
Note that the discharge channel of the supply passage and claim 4 according to claim 3, may be provided in at least one case.

Hereinafter, a plurality of embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
A valve lift control device according to a first embodiment of the present invention is shown in FIG. The valve lift control device 2 mounted on the vehicle controls the lift amount of the intake valve 4 of the internal combustion engine 3. The valve lift control device 2 includes a change mechanism 8 and an actuator 10.

  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 internal combustion engine 3. Specifically, in the change mechanism 8 of FIG. 2, a slider gear 14 that can move linearly with the control shaft 12 in the axial direction of the control shaft 12 is helically splined to 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 position in the axial direction. The input portion 15 is in contact with the intake cam 18 of the cam shaft 17, and the swing cam 16 is disposed so as to be in contact with the rocker arm 19 of the intake valve 4, and the relative phase difference between the input portion 15 and the swing cam 16 is arranged. Accordingly, the rocking angle of the rocker arm 19 changes. Therefore, in the change mechanism 8, the lift amount of the intake valve 4 (hereinafter simply referred to as the valve lift amount) changes as the axial position of the control shaft 12 changes. Such valve characteristics are adjusted. In this embodiment, the valve reaction force transmitted from the intake valve 4 to the control shaft 12 acts on the control shaft 12 as a thrust force directed to the side opposite to the actuator 10.

  The actuator 10 linearly drives the control shaft 12 of the change mechanism 8 in the axial direction. As shown in FIG. 3, the actuator 10 includes a case 20, a feed screw mechanism 21, a bearing 22, a restriction plate 23, a motor 24, a rotation angle sensor 25, and a drive circuit 26. The actuator 10 is mounted on the vehicle so that the left-right direction in FIG. 3 is substantially horizontal.

  The case 20 is configured by combining a case main body 30, a rotation restriction bush 31, a main body cover 32, and a circuit cover 33. The case main body 30 is formed in a stepped cylindrical shape, and includes an attachment portion 34, a locking portion 35, a fixing portion 36, and a flange portion 37 in order from one end portion in the axial direction to the other end portion. The attachment portion 34 is inserted and attached to the attachment hole 5 of the internal combustion engine 3, whereby the case main body 30 is positioned with respect to the internal combustion engine 3. The rotation restricting bush 31 is formed in a cylindrical shape and is press-fitted into the inner peripheral wall of the attachment portion 34. The main body cover 32 and the circuit cover 33 are each formed in a cup shape, and are fastened together with the flange portion 37 in a state where the opening edge portions are overlapped with each other. By this fastening, the main body cover 32 covers the opening 38 on the flange portion 37 side of the case main body 30, and a circuit chamber 39 is formed between the main body cover 32 and the circuit cover 33.

The feed screw mechanism 21 is a trapezoidal screw mechanism formed by meshing the rotary shaft 40 and the screw shaft 41, and is housed inside the case body 30.
As shown in FIG. 4, the rotary shaft 40 is configured by combining a rotary sleeve 42, a seal sleeve 43, a seal lid 44, and a circlip 45. The rotating sleeve 42 is formed in a cylindrical shape and is arranged substantially coaxially with the case main body 30. A female thread 46 having a trapezoidal cross section is formed on the inner peripheral wall of the intermediate portion in the axial direction of the rotating sleeve 42. A male screw 47 is formed on the outer peripheral wall at one axial end of the rotating sleeve 42. The seal sleeve 43 is formed in a cylindrical shape, and is attached substantially coaxially to the other axial end of the rotary sleeve 42. An oil seal 48 is interposed between the outer peripheral wall of the seal sleeve 43 and the inner peripheral wall of the mounting portion 34. The drive chamber 49 and the oil chamber 50 partitioned liquid-tightly by the oil seal 48 are the case body. 30 is formed inside. The seal lid 44 is formed in a disk shape, and is attached to the rotary sleeve 42 so as to cover the opening of the rotary sleeve 42 opposite to the seal sleeve 43. An O-ring 51 is interposed between the seal lid 44 and the rotary sleeve 42 and between the seal sleeve 43 and the rotary sleeve 42, and an inner hole of the rotary shaft 40 formed on the inner peripheral side of the sleeves 43, 42. 52 is in communication with the oil chamber 50 but is not in communication with the drive chamber 49. The circlip 45 is formed in a C shape and is fitted to the outer peripheral wall of the rotating sleeve 42 so as not to be relatively displaceable in the axial direction.

  As shown in FIG. 3, the screw shaft 41 is formed in a rod shape and is arranged substantially coaxially with the rotary shaft 40. One end of the screw shaft 41 in the axial direction protrudes outside the case body 30 and enters the oil passage 6 of the internal combustion engine 3, and is connected substantially coaxially to the control shaft 12 via a joint 53. Therefore, the screw shaft 41 reciprocates linearly with the control shaft 12 in the axial direction. As shown in FIG. 4, a male screw 54 having a trapezoidal cross section is formed on the outer peripheral wall of the screw shaft 41 on the other end side in the axial direction, and this male screw 54 is screwed with a female screw 46 of the rotary sleeve 42. Yes. Between the screw shaft 41 and the seal sleeve 43, a clearance that allows communication between the inner hole 52 of the rotating shaft 40 and the oil chamber 50 and linear movement of the screw shaft 41 is formed. Spline teeth 56 and 57 are formed on the outer peripheral wall of the axially intermediate portion of the screw shaft 41 and the inner peripheral wall of the rotation restricting bush 31 so as to mesh with each other by concave and convex fitting. That is, the outer peripheral wall of the screw shaft 41 is spline-fitted to the inner peripheral wall of the rotation restricting bush 31. The screw shaft 41 whose rotation in the circumferential direction is regulated by this fitting follows the forward / reverse rotational motion of the rotary shaft 40 and reciprocates linearly in the axial direction. That is, in the feed screw mechanism 21, the rotary motion of the rotary shaft 40 is converted into the linear motion of the screw shaft 41.

In the present embodiment, the spline teeth 56 and 57 are involute, and as shown in FIGS. 1 and 4, between the tooth bottom surface of the spline tooth 56 and the tooth tip surface of the spline tooth 57 and the tooth tip surface of the spline tooth 56. And clearances 58 are formed at a plurality of locations between the tooth bottom surface of the spline teeth 57. In FIG. 1, only some of the clearances 58 are denoted by reference numerals. One end of each clearance 58 in the axial direction communicates with the oil chamber 50. Further, a predetermined clearance 58 a between the tooth tip surface of the spline tooth 56 and the tooth bottom surface of the spline tooth 57 is also in communication with the oil passage 60 that penetrates the rotation restricting bush 31 in the radial direction. Here, as shown in FIGS. 3 and 4, the oil passage 60 communicates with an oil passage 61 that penetrates the mounting portion 34 in the radial direction and is connected to the discharge port of the oil pump 7 of the internal combustion engine 3. A portion of the lubricating oil discharged from the internal combustion engine 3 is supplied to the clearance 58 a through the oil passages 61, 60. The lubricating oil supplied to the oil chamber 50 directly from the clearance 58a or via the other clearance 58 flows into the inner hole 52 of the rotating shaft 40, thereby causing a friction portion of the feed screw mechanism 21 such as a screw. Lubricate the meshing portions of 46 and 54. An oil passage 62 that penetrates the attachment portion 34 in the axial direction communicates with the oil chamber 50 and the oil passage 6. Here, the oil passage 6 is connected to the oil pan on the suction side of the oil pump 7, and the lubricating oil is discharged from the oil chamber 50 through the oil passage 62 to the oil passage 6 and then returned to the oil pan.
The rotation restricting bush 31 corresponds to the “rotation restricting portion” described in the claims, the oil passages 60 and 61 correspond to the “supply passage” described in the claims, and the oil passage 62 claims. It corresponds to the “discharge path” described in the range.

  As shown in FIG. 4, the bearing 22 is a radial contact type ball bearing in which a ball-shaped rolling element 65 is sandwiched between an inner ring 63 and an outer ring 64, and is accommodated in a drive chamber 49 inside the case body 30. Has been. The inner ring 63 is fitted to the outer peripheral wall of the rotary sleeve 42, and the circlip 45 is engaged with one end of the inner ring 63 in the axial direction via a leaf spring 66. The outer ring 64 is fitted to the inner peripheral wall of the cylindrical portion 67 formed in the locking portion 35, and the locking portion 35 is engaged with the one axial end portion 64 a of the outer ring 64 via the washer 68. Yes. With the above configuration, the bearing 22 supports the radial force acting on the rotating shaft 40.

  The restriction plate 23 includes an elastic deformation portion 70, a screw fastening portion 71, and an engagement portion 72. The elastic deformation portion 70 is formed in a stepped cylindrical shape, and is disposed so as to be elastically deformable in a state where a part thereof is fitted to the outer peripheral wall of the outer ring 64. The screwing portion 71 is formed in an annular plate shape protruding from one end portion in the axial direction of the elastic deformation portion 70 to the outer peripheral side, and is screwed to the locking portion 35 at a location on the outer peripheral side of the cylindrical portion 67. The engaging portion 72 is formed in an annular plate shape protruding from the other axial end portion of the elastic deformation portion 70 toward the inner peripheral side, and is engaged with an end portion on the opposite side to the end portion 64 a of the outer ring 64. With the above configuration, when the elastic deformation portion 70 is elastically deformed following the axial displacement of the bearing 22, a restoring force corresponding to the elastic deformation amount is generated in the restriction plate 23, and the engagement portion 72 engages the bearing 22. It is pressed toward the stop 35 side.

As shown in FIG. 3, the motor 24 is a brushless motor having a motor rotor 80, a rotor fixing nut 81, and a motor stator 82, and is accommodated in a drive chamber 49 inside the case body 30.
As shown in FIGS. 4 and 5, the motor rotor 80 is configured by combining a rotor core 83 and a rotor magnet 84. The rotor core 83 is formed with an annular plate-like core protrusion 86 that protrudes from the one axial end of the cylindrical core body 85 toward the inner peripheral side. The core protrusion 86 is fitted to the outer peripheral wall of the intermediate portion in the axial direction of the rotary sleeve 42. An annular plate-shaped sleeve protrusion 87 protruding from the axial intermediate portion of the rotating sleeve 42 to the outer peripheral side is engaged with one axial end portion of the core protrusion 86, and a positioning key 88 is disposed on the protrusion 86. , 87. The rotor magnets 84 are permanent magnets having a circular arc shape in cross section, and a plurality of rotor magnets 84 are attached to the outer peripheral wall of the core body 85 at equal intervals in the circumferential direction.

  As shown in FIG. 4, a female screw 89 is formed on the inner peripheral wall of a rotor fixing nut 81 having a bottomed cylindrical shape. The female screw 89 is screwed with the male screw 47 of the rotating sleeve 42, whereby the core projecting portion 86 is sandwiched between the rotor fixing nut 81 and the sleeve projecting portion 87 and fixed to the rotating shaft 40. Therefore, the rotating shaft 40 also functions as a motor shaft.

  The motor stator 82 is configured by combining a stator core 90 and a stator coil 91. The stator core 90 is formed in a thick annular plate shape as a whole by stacking iron pieces, and is arranged substantially coaxially on the outer peripheral side of the motor rotor 80. The stator core 90 is screwed to the fixed portion 36 in a state of being fitted to the inner peripheral wall of the fixed portion 36. A plurality of slots 92 arranged at equal intervals in the circumferential direction are formed on the inner peripheral wall of the stator core 90. A stator coil 91 is wound around each slot 92 via a stator bobbin (not shown).

As shown in FIG. 3, the rotation angle sensor 25 is a non-contact sensor having a magnet unit 100 and a sensing unit 101.
As shown in FIG. 4, the magnet unit 100 is configured by combining a sensor magnet 102, a magnet holder 103, and a positioning plate 104, and is accommodated in a drive chamber 49 inside the case body 30. The sensor magnet 102 is a permanent magnet formed in an annular plate shape, and forms magnetic poles at a plurality of locations in the circumferential direction. The magnet holder 103 is fitted to the rotor fixing nut 81 and holds the sensor magnet 102 substantially coaxially with respect to the rotating shaft 40. The positioning plate 104 is fitted to the core body 85, the rotor fixing nut 81, and the magnet holder 103, and positions the sensor magnet 102 in the circumferential direction with respect to each rotor magnet 84.
A plurality of Hall elements 105 constituting the sensing unit 101 are arranged at equal intervals in the circumferential direction of the rotating shaft 40. Each Hall element 105 faces the magnet unit 100 and detects the rotation angle of the rotating shaft 40 by sensing the magnetic field generated by the sensor magnet 102.

  As shown in FIG. 3, the drive circuit 26 is an electric circuit formed by laminating a plurality of substrates 107 on which the circuit elements 106 are mounted, and is held by the main body cover 32 while being accommodated in the circuit chamber 39. The drive circuit 26 is electrically connected to the stator coils 91, the hall elements 105, and the control circuit 108 outside the case 20. Here, the control circuit 108 is an electric circuit mainly composed of a microcomputer or the like. The control circuit 108 that receives the output of each Hall element 105 through the drive circuit 26 recognizes the rotation angle of the rotary shaft 40 and further the axial position of the control shaft 12, and determines the actual position from the recognized axial position of the control shaft 12. Estimate the valve lift. Then, the control circuit 108 commands the drive circuit 26 to energize the difference between the estimated actual valve lift amount and the target valve lift amount. The drive circuit 26 that has received a command from the control circuit 108 generates a rotating magnetic field on the outer peripheral side of the motor rotor 80 by controlling energization to each stator coil 91 in accordance with the command. By receiving this generated magnetic field, the motor rotor 80 rotates together with the rotary shaft 40, and the screw shaft 41 and the control shaft 12 linearly move in the axial direction in accordance with the rotation, so that a target valve lift amount is realized. Note that the target valve lift amount is a physical amount determined based on the driving state of the vehicle such as the rotational speed of the internal combustion engine 3, the accelerator opening degree, and the like.

  As described above, in the first embodiment, the lubricating oil is supplied to the feed screw mechanism 21 inside the case body 30 through the clearance 58 between the screw shaft 41 and the rotation restricting bush 31. Here, the clearance 58 is formed between the spline teeth 56 and 57 which are provided on the screw shaft 41 and the rotation restricting bush 31 and are engaged with each other, so that the clearance 58 can be easily miniaturized by adjusting the size of the spline teeth 56 and 57. can do. Furthermore, since the clearance 58 is formed between the tooth bottom surface and the tooth tip surface of the spline teeth 56 and 57, the tooth surfaces of the spline teeth 56 and 57 are in contact with each other when the feed screw mechanism 21 is operated. Will not disappear. Therefore, according to the first embodiment, the minute clearance 58 can be formed at low cost, and the supply amount of the lubricating oil to the feed screw mechanism 21 can be suppressed to the necessary minimum. In the first embodiment, the lubricating oil for the internal combustion engine 3 is used for lubrication of the feed screw mechanism 21. However, a sufficient amount of lubricating oil can be obtained by suppressing the supply amount of the lubricating oil to the feed screw mechanism 21. Can be supplied to the internal combustion engine 3.

  Furthermore, in the first embodiment, the oil passages 60 and 61 for supplying the lubricating oil to the feed screw mechanism 21 are formed in the rotation restricting bush 31 and the case body 30, but the clearance communicating with these oil passages 60 and 61 is also provided. By forming 58 to be minute, fine processing of the oil passages 60 and 61 becomes unnecessary. Moreover, in the first embodiment, the lubricating oil discharged from the oil pump 7 and supplied to the feed screw mechanism 21 can be discharged through the oil passage 62 of the case body 30 and returned to the oil pump 7. Since fine processing is not required, such a lubricating oil circulation system can be constructed at low cost.

  In the first embodiment, the rotation restriction bush 31 is spline-fitted to the screw shaft 41, so that the rotation and axial deviation of the screw shaft 41 can be restricted while reducing the sliding resistance of the fitting portion. . And since the clearance 58 for lubricating oil supply is formed using the rotation control bush 31 which performs such a function, cost reduction can be promoted.

(Second embodiment)
As shown in FIG. 6, the second embodiment of the present invention is a modification of the first embodiment, and the description of the components that are substantially the same as those of the first embodiment will be omitted by attaching the same reference numerals. .
In the second embodiment, a plurality of oil passages 60 communicate with the oil passage 61 connected to the oil pump 7, and each oil passage 60 is connected to the tooth tip surface of the spline tooth 56 of the screw shaft 41 and the spline tooth 57 of the rotation restricting bush 31. Are communicated with a plurality of clearances 58a between the tooth bottom surfaces. According to such a second embodiment, the lubricating oil can be reliably supplied to the feed screw mechanism 21 using the plurality of clearances 58a.

As mentioned above, although 1st and 2nd embodiment of this invention was described, this invention is limited to those embodiment and is not interpreted.
For example, in the first and second embodiments, the rotation restricting bush 31 and the screw shaft 41 are spline-fitted, but any structure that restricts the rotation of the screw shaft 41 by the concave and convex fitting of these elements 31 and 41 can be used. A fitting structure other than the spline fitting may be employed. In the first and second embodiments, the lubricating oil supply clearance 58 is formed between the tooth bottom surface and the tooth tip surface of the spline teeth 56, 57, but the clearance 58 is formed by the spline teeth 56, 57. You may form between the tooth surfaces. Furthermore, in the first and second embodiments, the communication oil passage 60 of the oil passage 61 connected to the oil pump 7 includes the tip surface of the spline tooth 56 of the screw shaft 41 and the bottom surface of the spline tooth 57 of the rotation restricting bush 31. However, the oil passage 60 may communicate with the clearance 58 between the bottom surface of the spline teeth 56 and the top surface of the spline teeth 57.

  Further, in the first and second embodiments, the feed screw mechanism 21 in which the rotary shaft 40 and the screw shaft 41 are directly meshed with each other is used. However, the rotary shaft 40 and the screw shaft 41 are connected via gears, balls, or the like. Alternatively, a feed screw mechanism 21 that is indirectly connected may be used. In the first and second embodiments, the components 42 to 45 of the rotating shaft 40 are formed as separate members, but at least two of them may be formed as a single member. Furthermore, in the first and second embodiments, the screw shaft 41 and the control shaft 12 are coaxially connected to each other, but the screw shaft 41 may be eccentrically connected to the control shaft 12.

  In the first and second embodiments, a brushless motor is used as the motor 24 for driving the rotating shaft 40, but various known motors such as a DC motor may be used as the motor 24. In the first and second embodiments, the rotor magnet 84 may be embedded in the rotor core 83. Furthermore, in the first and second embodiments, the motor rotor 80 is sandwiched between the rotor fixing nut 81 and the sleeve protrusion 87 of the rotating sleeve 42 and fixed to the rotating shaft 40, but the motor rotor 80 is screwed. You may fix to the rotating shaft 40 (rotating sleeve 42) by press injection.

  In addition, in the first and second embodiments, the control circuit 108 is provided outside the case 20, but the control circuit 108 may be accommodated inside the case 20 together with the drive circuit 26. In the first and second embodiments, the Hall element 105 is used as a sensor element constituting the sensing unit 101. However, for example, a magnetoresistive element may be used as the sensor element.

  In addition, the change mechanism 8 combined with the actuator 10 has a configuration other than the configuration described in the first embodiment as long as it changes the valve lift according to the axial position of the control shaft 12. May be. For example, a change mechanism 8 that changes the lift amount of the exhaust valve of the internal combustion engine 3 may be used, and the valve reaction force transmitted to the control shaft 12 regardless of whether the target valve is a suction or an exhaust valve. Therefore, the changing mechanism 8 that urges the screw shaft 41 toward the actuator 10 may be used.

It is a figure which expands and shows the principal part of the actuator of the valve lift control apparatus by 1st embodiment, Comprising: It is II sectional drawing of FIG. It is the fragmentary sectional schematic diagram (A) and sectional drawing (B) which show the valve lift control apparatus by 1st embodiment. It is sectional drawing which shows the actuator of the valve lift control apparatus by 1st embodiment. It is sectional drawing which expands and shows the principal part of the actuator of the valve lift control apparatus by 1st embodiment. It is a figure which expands and shows the principal part of the actuator of the valve lift control apparatus by 1st embodiment, Comprising: It is VV sectional drawing of FIG. It is a figure which expands and shows the principal part of the actuator of the valve lift control apparatus by 2nd embodiment, Comprising: It is sectional drawing corresponding to FIG.

Explanation of symbols

2 valve lift control device, 3 internal combustion engine, 4 intake valve, 6 oil passage, 7 oil pump, 8 changing mechanism, 10 actuator, 12 control shaft, 20 case, 21 feed screw mechanism, 22 bearing, 23 regulating plate, 24 motor , 25 Rotation angle sensor, 26 Drive circuit, 30 Case body, 31 Rotation restriction bush (rotation restriction part), 32 Body cover, 33 Circuit cover, 40 Rotation shaft, 41 Screw shaft, 50 Oil chamber, 52 Inner hole, 56, 57 Spline teeth, 58 (a) Clearance, 60, 61 Oil path (supply path), 62 Oil path (discharge path)

Claims (4)

In 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, an actuator that changes the lift amount according to the axial position of the control shaft by linearly driving a control shaft. And
A feed screw mechanism having a screw shaft that linearly moves with the control shaft in the axial direction and a rotary shaft that rotates in the circumferential direction, and that converts the rotary motion of the rotary shaft into linear motion of the screw shaft;
A case that includes a rotation restricting portion that restricts rotation of the screw shaft by fitting an irregularity to an outer peripheral wall of the screw shaft, and that houses the feed screw mechanism therein;
With
The screw shaft and the rotation restricting portion are spline fitted to each other,
In the spline teeth provided on the screw shaft and the rotation restricting portion, a clearance is provided between the tooth bottom surface and the tooth tip surface that mesh with each other,
An actuator for a valve lift control device, wherein a lubricating fluid is supplied between the screw shaft and the rotation restricting portion through the clearance, and the supplied lubricating fluid is supplied into the case .   The actuator for a valve lift control device according to claim 1, wherein the lubricating fluid is a lubricating fluid for the internal combustion engine. The actuator of the valve lift control device according to claim 1 or 2 , wherein the case has a supply path for supplying the lubricating fluid from the outside to the clearance. The actuator of the valve lift control device according to any one of claims 1 to 3 , wherein the case has a discharge path for discharging the lubricating fluid supplied to the inside to the outside.

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