JP2010038038A - Spring seating surface structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a spring seating surface suppressing abrasion of a member forming a spring seating surface. <P>SOLUTION: In a pressing mechanism 20 for applying pressing force in a rotational direction to the input arm 17 of a valve lift variable mechanism 14, recovery grooves are formed in the seat seating surface of a housing 71. Abrasion powders produced due to abrasion of the seat seating surface by sliding the seat seating surface of the housing 71 and a spring seat 72 are recovered in the recovery grooves, and the abrasion powders are prevented from remaining between the seat seating surface and the spring seat 72, thereby preventing the abrasion powders from functioning as abrasive. Accordingly, promotion of abrasion is suppressed. The recovery grooves have radially extending first recovery grooves and annular second recovery grooves continuing to the peripheral ends of the first recovery grooves. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a structure of a spring seat surface portion with which a spring that expands and contracts abuts. In particular, the present invention relates to a measure for improving the wear resistance of the members constituting the spring seat portion.

  2. Description of the Related Art Conventionally, variable valve mechanisms that change operating characteristics such as valve lift amounts and operating angles of intake valves and exhaust valves according to the operating state of an internal combustion engine are known (for example, Patent Document 1 and Patent Document 2). See).

  This variable valve mechanism has an intermediate drive mechanism disposed between a cam of a camshaft and a valve (for example, an intake valve). This intermediary drive mechanism is composed of an input portion (cam hitting member) that comes into contact with the cam and two swings that come into contact with the valve by a slider gear that is linked to the axial movement of the control shaft that is inserted through the central hole of the rocker shaft. By rotating the cam (valve striking member) relatively, the relative phase difference between them is changed, and the lift amount of the valve is adjusted.

  On the outer periphery of the slider gear, helical splines are provided in three rows in the axial direction. The input portion is provided on the center helical spline of the slider gear, and the two swings are provided on the two side helical splines of the slider gear. Each moving cam is spline-fitted. The inclination directions of the two side helical splines are opposite to the center helical spline.

  Further, an urging mechanism including a coil spring (referred to as a lost motion spring) that applies an urging force for bringing the input portion into contact with the cam of the camshaft is installed in the vicinity of the input portion.

  This urging mechanism has a structure in which a spring seat, a coil spring (hereinafter simply referred to as a spring), and a lifter are accommodated in a housing. Specifically, the housing includes a spring accommodating portion having a substantially cylindrical inner space, and a lower side (the input portion side) of the spring accommodating portion is opened. Moreover, the upper surface (ceiling surface) in the spring accommodating part of this housing is formed as a seat seat surface. A spring is brought into contact with the seat surface via a spring seat. Also, a lifter is interposed between the spring and the input part, and the spring is interposed between the lifter and the spring seat in a compressed state, and the urging force of the spring is applied to the input part via the lifter. It is to be granted.

  With such a configuration, the urging force of the spring is applied to the input portion via the lifter, and the input portion is urged in the rotational direction in contact with the cam of the camshaft. Thereby, when the camshaft rotates, the input portion is prevented from moving away from the cam, and the pressing force from the cam to the input portion is reliably transmitted.

The urging mechanism including such a spring seat, a spring, and a lifter is also applied to a general engine valve mechanism (see, for example, Patent Document 3 and Patent Document 4 below).
JP 2001-263015 A JP 2007-113516 A Japanese Patent Laid-Open No. 2003-161121 JP 2002-70510 A

  By the way, in the urging mechanism as described above, the spring seat may rotate relative to the housing, and this rotation may cause wear on the seat surface of the housing. It was. This will be described in detail below.

  In the above urging mechanism, when the spring is compressed (when the valve is lifted), twisting occurs in the direction of increasing the number of turns, and conversely, when the spring is extended (when the valve is not lifted) Twist occurs in the direction in which the number of turns decreases. And since the said spring seat is contact | abutting or fixed to the spring, when the said valve lift operation | movement is repeated, the twist of the said spring will be transmitted to a spring seat and this spring seat will rotate around an axial center.

  In general, the housing is made of aluminum from the viewpoint of weight reduction and workability of the biasing mechanism, while the spring seat is required to have a relatively high strength because it receives a biasing force from a spring, for example, spring steel. (Spring steel). For this reason, when the rotation of the spring seat as described above occurs, the aggressiveness of the spring seat against the housing may increase, and the seat seating surface may be worn.

  When such wear occurs, the wear powder is interposed between the seat seat surface and the spring seat, and the spring seat rotates in this state. In such a situation, the wear powder functions as an abrasive, and the seat seat surface wears further.

  Further, the above-described rotation of the spring seat is caused by the following factors. In other words, by changing the contact position of the input unit with respect to the lifter, the contact position of the input unit is set to a position off the axis of the lifter for the purpose of suppressing uneven wear of the lifter. There is a case where a configuration in which the lifter is rotated around the axis by an external force is employed. In this case, the rotational force of the lifter is transmitted to the spring seat via the spring, and the spring seat rotates. In this case as well, the seat seat surface is worn as described above.

  It is known that the higher the mounting load of the spring (the compressive force of the spring during assembly), the more the rotation of the spring seat can be suppressed. That is, if the attachment load of the spring in the initial state is set high, the rotation of the spring seat can be suppressed, and the wear of the seat surface can be suppressed to a low level. However, if the seat seat surface wears out with long-term use, the spring mounting load will be reduced by this amount of wear (the seat seat surface retracted from the spring), and the rotation of the spring seat will gradually increase. Go.

  In other words, seat seat surface wear → decrease in spring mounting load → increase in rotation of the spring seat → acceleration of seat seat surface wear due to abrasion powder acting as an abrasive → further decrease in spring mounting load, etc. The vicious circle continues and there is a possibility that the seat seating surface wears rapidly from a certain point.

  Such a problem may occur not only in the urging mechanism of the variable valve mechanism described above but also in a general engine valve mechanism.

  As a measure for suppressing the wear of the seat surface as described above, surface modification of the seat surface can be mentioned. For example, the alumite treatment is performed to increase the hardness of the seat seat surface.

  However, there is a limit to the film thickness dimension that can be modified when this surface modification is performed, and after wear for the modified film thickness occurs, a material with low hardness is exposed. As a result, wear is rapidly accelerated.

  As another measure for suppressing wear, for example, Patent Document 2 discloses that an opening is provided on the upper surface of the housing, and lubricating oil is introduced from the opening into the spring accommodating portion. However, in particular, in the case of the variable valve mechanism described above, the spring seat is in contact with the seat seat surface, which is the ceiling surface of the spring accommodating portion, so oil introduced from the opening is applied to the seat seat surface. It is difficult to pour, and it is difficult to obtain a sufficient effect for suppressing wear.

  This invention is made | formed in view of this point, The place made into the objective is to provide the spring seat surface part structure which can suppress abrasion of the member which comprises a spring seat surface part.

-Principle of solving the problem-
The solution principle of the present invention taken in order to achieve the above object is to form a space for collecting wear powder generated between members in sliding contact with each other in at least one of the members in sliding contact with each other. By preventing the wear powder from remaining between these members, it is possible to avoid the wear powder from functioning as an abrasive, thereby suppressing the promotion of wear.

-Solution-
Specifically, the present invention provides a seat member having a seat surface that receives a reaction force from a spring that applies a biasing force toward the lifter, and a spring seat interposed between the seat surface of the seat member and the spring. Assuming a spring seat structure with This spring seat surface structure is generated by sliding between the seat member and the spring seat on at least one of the seat surface of the seat member and the seat surface abutting surface of the spring seat contacting the seat surface. A collecting groove for discharging and collecting the worn powder from between the seating surface and the seating surface contact surface is provided.

  Due to this specific matter, when the spring seat rotates with respect to the seat member, abrasion powder is generated by the sliding contact between the seat surface of the seat member and the seat contact surface of the spring seat. The wear powder is discharged toward the collection groove with the rotation of the spring seat and collected in the collection groove. For this reason, the amount of wear powder existing between the seat surface of the seat member and the seat contact surface of the spring seat is greatly reduced, and this wear powder functions as an abrasive and wears away. The situation of encouraging is avoided and the amount of wear can be suppressed.

  Specific examples of the collection groove include the following. That is, the recovery groove is formed on the seating surface of the seating surface member and extends radially with respect to the center of the seating surface, and is continuously formed on the outer end of the first recovery groove and An annular second recovery groove for discharging the wear powder to the outside of the outer edge of the spring seat is provided.

  As a result, the wear powder collected in the first collection groove along with the rotation of the spring seat is pushed out to the outer peripheral side by the wear powder sequentially collected in the first collection groove, and the second collection groove Reach. And since this 2nd collection groove | channel is formed in the position which discharges abrasion powder to the outer side rather than the outer edge of a spring seat, the abrasion powder once collect | recovered by the collection groove is the seat surface of a seat surface member, and a spring seat. It is possible to avoid returning to the seating surface contact surface again and to obtain a high wear suppression effect.

  Specific examples of the application form of the spring seat surface structure described above include the following. That is, the spring is applied with a biasing force via a lifter to the variable valve lift mechanism of the internal combustion engine. The variable valve lift mechanism includes an output member for applying a pressing force in the lift direction to the valve, an input member for receiving a pressing force from a cam of the valve operating system, and a pressing force from the cam from the input member. A phase difference variable mechanism that transmits to the output member and changes a relative phase difference between the output member and the input member in the rotation direction, and the spring moves toward the cam with respect to the input member. The biasing force in the rotating direction is applied.

  Since the above-described spring seat surface portion structure suppresses the wear of the seat surface of the seat member and the like, the spring biasing force (attachment load) is not significantly reduced. For this reason, the biasing force in the direction of rotation from the spring to the input member toward the cam is also stably maintained, and the input portion is prevented from moving away from the cam when the camshaft rotates. The pressing force is reliably transmitted to the portion, and the operation reliability of the variable valve lift mechanism can be improved.

  In the present invention, at least one of these members is formed with a collection groove for collecting wear powder generated between the bearing member and the spring seat that are in sliding contact with each other, and the wear powder is generated between these members. It is trying not to remain. For this reason, the situation where abrasion powder functions as an abrasive | polishing agent and wear accelerates | stimulates can be avoided.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. This embodiment demonstrates the case where this invention is applied to the variable valve mechanism provided in the valve system of the engine for motor vehicles.

-Configuration of engine and variable valve mechanism-
First, prior to the description of the features of the present invention, the configuration of the variable valve mechanism for the engine according to the present embodiment will be described. Here, as shown in FIGS. 1 and 2, an in-line four-cylinder DOHC engine is taken as an example of the engine 1.

  FIG. 1 is an enlarged cross-sectional view showing a structure around a cylinder head 2 in a predetermined cylinder among the first cylinder to the fourth cylinder of the engine 1. In this engine 1, a combustion chamber 6 is defined by a cylinder head 2, a cylinder block 3, and a piston 5, and an intake passage 7 and an exhaust passage 8 are connected to the combustion chamber 6 in a state of being branched into two. (Only one is shown in FIG. 1). The intake passage 7 and the combustion chamber 6 are connected and cut off by the opening / closing operation of the intake valve 9, and the exhaust passage 8 and the combustion chamber 6 are connected and cut off by the opening / closing operation of the exhaust valve 10. Two intake valves 9 and two exhaust valves 10 are provided for each cylinder.

  The cylinder head 2 is provided with an intake camshaft 11 and an exhaust camshaft 12 for driving the intake valve 9 and the exhaust valve 10. The intake camshaft 11 and the exhaust camshaft 12 are rotated by transmission of rotational force from the crankshaft of the engine 1. The intake camshaft 11 and the exhaust camshaft 12 are provided with an intake cam 11a and an exhaust cam 12a, respectively. Then, when the intake cam 11a and the exhaust cam 12a rotate integrally with the intake camshaft 11 and the exhaust camshaft 12, the intake valve 9 and the exhaust valve 10 are opened and closed.

The engine 1 has a maximum lift amount of the intake valve 9 and an operating angle of the intake cam 11a (the operating angle of the intake valve 9) as a variable valve lift mechanism that changes the valve characteristics of the engine valves such as the intake valve 9 and the exhaust valve 10. A variable valve lift mechanism 14 is provided between the intake cam 11 a and the intake valve 9. By driving the variable valve lift mechanism 14, for example, the maximum lift amount and the operating angle are controlled to increase as the engine operation state that requires a larger intake air amount is reached. This is because the larger the maximum lift amount and the operating angle, the more efficiently the air is sucked into the combustion chamber 6 from the intake passage 7 and the above-described requirement regarding the intake air amount can be satisfied.

  Next, the detailed structure of the variable valve lift mechanism 14 will be described.

  The variable valve lift mechanism 14 includes an input arm (input member) 17 that is pushed by the rotating intake cam 11a and swings about the axis of the rocker shaft 15 and the control shaft 16 extending in parallel with the intake camshaft 11, and this An output arm (output member) 18 that swings around the axis line based on the swing of the input arm 17 is provided.

  A roller 19 is rotatably attached to the input arm 17. The input arm 17 is urged toward the intake cam 11a by an urging mechanism 20 described later so that the roller 19 is pressed against the intake cam 11a. Further, the output arm 18 is pressed against the rocker arm 21 when swinging, and lifts the intake valve 9 via the rocker arm 21.

  The base end portion of the rocker arm 21 is supported by a lash adjuster 22, and the distal end portion of the rocker arm 21 is in contact with the intake valve 9. The rocker arm 21 is urged toward the output arm 18 by the valve spring 24 of the intake valve 9, whereby a roller 23 rotatably supported between the base end portion and the distal end portion of the rocker arm 21 is applied to the output arm 18. It is pressed. The lash adjuster 22 is a hydraulic type and has a known configuration that functions so as to always keep the tappet clearance of the intake valve 9 at zero.

  Therefore, when the input arm 17 and the output arm 18 swing based on the rotation of the intake cam 11a, the output arm 18 lifts the intake valve 9 via the rocker arm 21, and the intake valve 9 is opened and closed. In the variable valve lift mechanism 14, the maximum lift amount of the intake valve 9 and the intake air are changed by changing the relative position (phase difference in the rotational direction) of the input arm 17 and the output arm 18 in the swing direction. The operating angle of the cam 11a with respect to the intake valve 9 is variable. That is, as the input arm 17 and the output arm 18 are brought closer to each other in the swing direction, the maximum lift amount and the operating angle of the intake valve 9 become smaller. Conversely, as the input arm 17 and the output arm 18 are separated from each other in the swinging direction, the maximum lift amount and the operating angle of the intake valve 9 increase. Thus, the phase difference variable mechanism referred to in the present invention is configured.

  Next, FIG. 2 shows the structure for attaching the variable valve lift mechanism 14 to the cylinder head 2 and the structure for attaching the rocker shaft 15 and the control shaft 16 used for driving the variable valve lift mechanism 14 to the cylinder head 2. The description will be given with reference.

  FIG. 2 is a plan view of the cam carrier 41 formed on the upper portion of the cylinder head 2 as viewed from above.

The cam carrier 41 is provided with a plurality of standing wall portions 45 corresponding to each cylinder so as to be parallel to each other. These standing wall portions 45 are formed of a lightweight material such as an aluminum alloy in order to reduce the weight of the engine 1. The variable valve lift mechanism 14 is disposed between the standing wall portions 45 so as to correspond to the cylinders of the engine 1. Adjacent valve lift variable mechanisms 14 are separated by a standing wall 45. The rocker shaft 15 and the control shaft 16 used for driving the variable valve lift mechanism 14 penetrate the variable valve lift mechanisms 14 and the standing wall portions 45. The variable valve lift mechanisms 14 are supported by the standing wall portions 45 via the rocker shaft 15. Further, the input arm 17 and the output arm 18 of the mechanism 14 are sandwiched between the standing wall portions 45.

  The rocker shaft 15 is formed in a pipe shape, and the control shaft 16 is supported inside the rocker shaft 15 so as to be reciprocally movable in the axial direction. Both the rocker shaft 15 and the control shaft 16 are formed by using a material having high strength such as an iron-based material with an emphasis on ensuring necessary strength. The control shaft 16 has a base end portion (left end portion in the figure) connected to the actuator 47 and is moved in the axial direction of the shaft 16 through the drive of the actuator 47. The variable valve lift mechanism 14 of each cylinder is driven through movement of the control shaft 16 in the axial direction, and changes the relative position of the input arm 17 and the output arm 18 in the swing direction.

  Next, the internal structure of the variable valve lift mechanism 14 will be described with reference to FIGS.

  FIG. 3 is a cutaway perspective view showing the inner structure of the input arm 17 and the output arm 18 in the variable valve lift mechanism 14.

  The variable valve lift mechanism 14 includes a cylindrical slider 26 disposed inside the input arm 17 and the output arm 18. The rocker shaft 15 is inserted into the slider 26, and the control shaft 16 is inserted into the rocker shaft 15. When the control shaft 16 moves in the axial direction, the movement is transmitted to the slider 26 by the engaging member 61 (see FIG. 5) attached to the control shaft 16, and the slider 26 is also displaced in the axial direction. On the outer wall of the slider 26, an input gear 27a having a helical spline (center helical spline) 27 is fixed at the center in the longitudinal direction, and output gears 29a and 29a having helical splines (side helical splines) 29 at both ends in the longitudinal direction. Is fixed.

  On the other hand, as shown in FIG. 4, an annular internal gear 28 a having a helical spline 28 is formed on the inner wall of the input arm 17, and circles having helical splines 30, 30 are formed on the inner walls of the output arms 18, 18. Annular internal gears 30a, 30a are formed. The internal gear 28a of the input arm 17 is meshed with the input gear 27a (FIG. 3) of the slider 26, and the internal gear 30a of the output arm 18 is meshed with the output gear 29a (FIG. 3) of the slider 26. The helical splines 27 and 28 and the helical splines 29 and 30 have different inclination angles, for example, the inclination directions of the tooth traces are opposite to each other.

When the slider 26 is displaced in the coaxial line direction based on the movement of the control shaft 16 in the axial direction, the input arm 17 and the output arm 18 are swung by the meshing of the helical splines 27 and 29 and the helical splines 28 and 30. The relative position with respect to the direction is changed. Specifically, as the slider 26 is displaced in the direction of arrow L in FIG. 3, the relative positions of the input arm 17 and the output arm 18 in the swinging direction are changed so as to approach each other, and the slider 26 is moved in the direction of arrow H. The relative positions are changed so as to be separated from each other as they are displaced. By changing the relative positions of the input arm 17 and the output arm 18 in the swinging direction, the maximum lift amount and the operating angle of the intake valve 9 when the output arm 18 swings due to the rotation of the intake cam 11a can be made variable. . Therefore, in the variable valve lift mechanism 14, the input arm 17 and the output arm 18 serve as a variable drive unit that is driven to change the valve characteristic of the intake valve 9.

  Lubricating oil is supplied to the inside of the input arm 17 and the output arm 18 from an oil pump driven by the engine 1 through an oil passage, and the input arm 17, the output arm 18, the slider 26 and the like are supplied by the lubricating oil. Lubricating between gears (splines) meshing with each other is performed.

  FIG. 5 is a cross-sectional view showing the internal structure of the input arm 17, the output arm 18, the slider 26, the rocker shaft 15, and the like.

  As shown in the figure, the rocker shaft 15 and the control shaft 16 for driving the variable valve lift mechanism 14 pass through a plurality of standing wall portions 45 provided in the cylinder head 2, and between these standing wall portions 45. The input arm 17 and the output arm 18 of the variable valve lift mechanism 14 located at the same position are also penetrated.

  The engagement of the slider 26 with the control shaft 16 is realized using an engagement member 61. The slider 26 and the control shaft 16 are connected by the engaging member 61 so as to be integrally movable in the axial direction of the control shaft 16. The engaging member 61 passes through the bush 35 inserted into the groove 34 formed to extend in the circumferential direction on the inner peripheral surface of the slider 26, and the elongated hole 33 of the rocker shaft 15 through the bush 35. In this state, a pin 51 is inserted into the control shaft 16 in the radial direction. The elongated hole 33 through which the pin 51 passes extends in the axial direction of the rocker shaft 15 (left and right direction in the figure). The elongated hole 33 and the pin 51 can only move relative to each other in the axial direction, and cannot move relative to the rocker shaft 15 in the circumferential direction.

  Accordingly, when the control shaft 16 moves in the axial direction, the pin 51 moves along the elongated hole 33 of the rocker shaft 15 accordingly. As a result, the pin 51 is pressed against the inner surface of the groove 34 via the outer surface of the bush 35, and the slider 26 is displaced in the axial direction of the control shaft 16. The relative position of the input arm 17 and the output arm 18 in the swing direction is variable through the displacement of the slider 26, and the input arm 17 and the output arm 18 swing due to the rotation of the intake cam 11a (FIG. 1). The maximum lift amount and operating angle of the intake valve 9 at that time are variable. When the input arm 17 and the output arm 18 swing, the slider 26 swings (rotates) in the circumferential direction accordingly. At this time, the inner surface of the groove 34 of the slider 26 slides with respect to the outer surface of the bush 35, and the bush 35 and the pin 51 also try to swing in the circumferential direction due to the frictional force therebetween. However, the rocking of the bush 35 and the pin 51 following the rocking of the slider 26 is regulated by the opposing inner surface of the elongated hole 33 of the rocker shaft 15. 5 is a shim for adjusting the position of the input arm 17 and the output arm 18 in the axial direction.

-Energizing mechanism 20-
Next, the configuration of the urging mechanism 20 that is a characteristic part of the present embodiment will be described. The biasing mechanism 20 applies a biasing force in the rotational direction toward the intake cam 11a to the input arm 17 so that the roller 19 provided on the input arm 17 is pressed against the intake cam 11a as described above. It is. Specifically, as shown in FIG. 1, the input arm 17 has a protruding piece 17 a formed at a position having a phase of about 180 ° around the axis with respect to the position where the roller 19 is disposed. In addition, by applying an urging force (downward urging force in FIG. 1) from the urging mechanism 20 to the protruding piece 17a, an urging force in the rotational direction toward the intake cam 11a is given.

  FIG. 6 is an exploded perspective view of the urging mechanism 20. As shown in FIG. 6, the urging mechanism 20 has a structure in which a housing (seat surface member) 71, a spring seat 72, a spring (generally called a lost motion spring) 73, and a lifter 74 are assembled together. Yes. This will be specifically described below.

  The housing 71 is made of, for example, aluminum, and includes a main body portion 71a formed in a bottomed cylindrical shape and a flange portion 71b extending in the horizontal direction from the lower end edge of the main body portion 71a.

  The inside of the main body 71a is formed as a spring accommodating space 71c that is substantially cylindrical and opens downward. That is, the spring seat 72, the spring 73, and the lifter 74 are sequentially inserted into the spring housing space 71c and assembled together.

  On the other hand, the flange 71b of the housing 71 is formed with bolt holes 71d and 71d at two locations, and the housing 71 is attached to the engine 1 by the bolt holes 71d and 71d. For example, a bolt hole (not shown) is formed in the standing wall portion 45 of the cam carrier 41, and the housing 71 is connected to the cam carrier 41 in a state where the bolt hole and the bolt hole 71d of the flange portion 71b are aligned. The housing 71 is attached corresponding to each cylinder by being placed on and fastening bolts being inserted through the respective bolt holes. In this attached state, the lower surface of the lifter 74 comes into contact with the protruding piece 17 a of the input arm 17.

  The spring seat 72 is formed of a ring-shaped plate material made of spring steel. The outer diameter of the spring seat 72 is substantially the same as or slightly smaller than the inner diameter of the spring accommodating space 71c provided in the main body 71a of the housing 71 (for example, a dimension smaller by about 2 mm). And is set slightly larger than the outer diameter of the spring 73. Further, the inner diameter dimension of the opening 72 a formed in the central portion of the spring seat 72 is set slightly smaller than the inner diameter dimension of the spring 73. As a result, the entire one end edge (upper end edge) of the spring 73 is brought into contact with the spring seat 72, and the load (reaction force) from the spring 73 can be received by the entire spring seat 72. It has become. The thickness dimension of the spring seat 72 is set to about 2 mm. These values are not limited to this, and can be set as appropriate.

  The spring 73 is a coil spring formed of spring steel, and is disposed in a compressed state between the spring seat 72 and the lifter 74 in the spring accommodating space 71c. That is, the extension force (elastic restoring force) of the spring 73 acts on the lifter 74 and is applied from the lifter 74 to the protruding piece 17 a of the input arm 17.

  The elastic restoring force of the spring 73, that is, the urging force of the input arm 17 against the protruding piece 17a, becomes stronger as the initial compression amount of the spring 73 is set larger, and the initial compression amount of the spring 73 is smaller. It is weak, but it is set appropriately as needed.

The lifter 74 is a bottomed cylindrical member, and includes a cylindrical portion 74a and a bottom surface portion 74b. The cylindrical portion 74 a has an outer diameter dimension set slightly smaller than the inner diameter dimension of the spring accommodating space 71 c, while its inner diameter dimension is set slightly larger than the outer diameter dimension of the spring 73. Further, the height dimension (dimension in the direction along the axis) of the cylindrical portion 74a is set smaller than the height dimension of the spring accommodating space 71c.

  The bottom surface portion 74b of the lifter 74 is provided with a protruding portion 74c whose central portion slightly protrudes downward, and the lower surface of the protruding portion 74c is in contact with the protruding piece 17a of the input arm 17. Yes. The lower edge of the spring 73 is in contact with the inner surface of the bottom surface portion 74b of the lifter 74 (the bottom surface of the internal space of the lifter 74).

  With the above configuration, the housing 71 and the spring seat 72 constitute a spring seat surface portion in the present invention.

  The feature of this embodiment is the configuration of the upper surface (ceiling surface) 75 of the inner surface of the main body 71a of the housing 71. That is, it is in the shape of the ceiling surface of the spring accommodating space 71c. Hereinafter, this surface is referred to as a seat seat surface 75.

  FIG. 7A is a bottom view of the spring accommodating space 71c of the housing 71 and its peripheral portion as viewed from below. Moreover, FIG.7 (b) is sectional drawing along the BB line in Fig.7 (a). In these drawings, the spring seat 72 and the spring 73 are indicated by phantom lines.

  As shown in these drawings, recovery grooves 76 and 77 are formed in the seat seating surface 75 of the housing 71. The collection grooves 76 and 77 are grooves for collecting wear powder generated by sliding between the seat seat surface 75 and the upper surface (seat surface contact surface) 72a of the spring seat 72, and extend radially. A plurality (four in this embodiment) of first recovery grooves 76, 76,... And an annular second recovery groove 77 formed continuously at the outer peripheral end of the first recovery groove 76 are provided. . The number of the first recovery grooves 76 is not limited to this.

  More specifically, the first recovery groove 76 is not formed in the center portion of the seat seat surface 75, and the seat seat is formed from a position on the outer peripheral side having a predetermined dimension from the center of the seat seat surface 75. The surface 75 extends linearly toward the outer peripheral side end. For example, the longitudinal dimension of the first recovery groove 76 is set to about 1/3 of the inner diameter dimension of the seat seat surface 75.

  The second recovery groove 77 is formed along the outer peripheral edge of the seat seat surface 75, and its inner diameter is set slightly smaller than the outer diameter of the spring seat 72, The outer diameter dimension is set to be slightly larger than the outer diameter dimension of the spring seat 72 and substantially coincident with the inner diameter dimension of the spring accommodating space 71c.

  The collection grooves 76 and 77 have the same depth dimension, and are set to a depth dimension that is approximately half the thickness dimension of the main body 71a of the housing 71, for example.

-Wear powder recovery operation-
Next, the operation of collecting the wear powder by the collecting grooves 76 and 77 configured as described above will be described.

  With the operation of the variable valve lift mechanism 14, the spring seat 72 rotates with respect to the housing 71. That is, relative rotation occurs between the seat seating surface 75 of the housing 71 and the spring seat 72 (the direction of rotation is indicated by an arrow A in FIG. 7A). In addition, since the housing 71 is made of aluminum, the spring seat 72 is made of spring steel, so that the seat seating surface 75 of the housing 71 is worn with the relative rotation of both, and the wear powder associated therewith. Occurs.

  As described above, the cause of the rotational force generated in the spring seat 72 is that the torsion accompanying the expansion and contraction of the spring 73 is transmitted to the spring seat 72 and the input arm is used to suppress the uneven wear of the lifter 74. For example, the contact position of the 17 projecting pieces 17 a is set at a position deviated from the axis of the lifter 74, the lifter 74 is forcibly rotated, and the rotational force is transmitted to the spring seat 72.

  As described above, when the seat seat surface 75 of the housing 71 is attacked by the spring seat 72 and wear is generated, and wear powder accompanying the wear is generated, the wear powder is generated along with the rotation of the spring seat 72. After being moved by a predetermined angle along the circumferential direction, the first recovery groove 76 is recovered. Such an operation is performed at the position where the first recovery grooves 76, 76,... Are formed. For this reason, the amount of abrasion powder existing between the seat seat surface 75 of the housing 71 and the upper surface (lower surface in FIG. 7B) 72a of the spring seat 72 is greatly reduced. The situation where the wear powder functions as an abrasive and promotes wear is avoided, and further acceleration of wear is suppressed.

  Further, the wear powder collected in each of the first collection grooves 76, 76,... Is pushed out to the outer peripheral side by the wear powder sequentially collected in the first collection groove 76 and reaches the second collection groove 77. . Since the outer peripheral edge of the second recovery groove 77 is located outside the outer edge of the spring seat 72, the wear powder once recovered in the second recovery groove 77 is removed from the seat seat surface 75 of the housing 71. And the return to the upper surface 72a of the spring seat 72 can be avoided, and the above-described wear suppression effect can be enhanced.

(Modification)
Next, a plurality of modifications will be described. The modification described below is a modification of the shape of the first recovery groove 76, and other configurations and operations are the same as those of the above-described embodiment. Accordingly, only the shape of the first recovery groove 76 will be described here.

  FIG. 8 is a diagram corresponding to FIG. 7A in the first modification. As shown in FIG. 8, the first recovery groove 76 in the present modification is formed in a substantially sector shape when the seat seat surface 75 is viewed from a direction along its axis. That is, the width dimension (dimension in the direction along the circumferential direction of the seat seat surface 75) gradually increases toward the outer peripheral side.

  FIG. 9 is a diagram corresponding to FIG. 7A in the second modification. As shown in FIG. 9, the first recovery groove 76 in this modification is formed in a curved shape that gradually extends toward the outer peripheral side in the rotation direction of the spring seat 72 (counterclockwise direction in the drawing).

  According to these modified examples, it becomes possible to smoothly feed the wear powder collected in the first collection groove 76 toward the second collection groove 77, and the wear powder is separated from the seat seat surface 75 of the housing 71 and the spring. It is possible to reliably prevent the sheet 72 from returning to the upper surface 72a of the sheet 72 again.

-Other embodiments-
In the embodiment and the modification described above, the case where the present invention is applied to the urging mechanism 20 of the variable valve lift mechanism 14 provided in the valve train of the automobile engine has been described. The present invention is not limited to this, and can also be applied to a general engine valve mechanism. The present invention can also be applied to a plunger reciprocating mechanism applied to a fuel pump or the like.

  In the above-described embodiments and modifications, the case where the variable valve lift mechanism 14 is provided on the intake side has been described. However, a similar variable valve lift mechanism is provided on the exhaust side, and a similar urging mechanism is provided. May be.

  Further, in the above-described embodiment and modification, the recovery grooves 76 and 77 are formed on the seat seat surface 75 of the housing 71. The present invention is not limited to this, and a similar collecting groove may be formed on the upper surface 72a of the spring seat 72 (the contact surface with the seat seat surface 75). In addition, a collection groove may be formed on both the seat seat surface 75 and the upper surface of the spring seat 72.

  Furthermore, in the said embodiment and modification, the main-body part 71a of the housing 71 was made into the bottomed cylindrical shape, and it was set as the structure which does not supply lubricating oil to the inside. The present invention is not limited to this, and an opening may be formed on the upper surface of the main body 71a of the housing 71, and lubricating oil may be supplied from the opening toward the spring accommodating space 71c. In this case, it can be expected that the wear powder collected in each of the collection grooves 76 and 77 is discharged together with the lubricating oil that flows down from the spring accommodating space 71c, and the wear suppression effect of the seat seat surface 75 can be further enhanced.

It is sectional drawing which shows the cylinder head of the engine which concerns on embodiment, and its peripheral part. It is a top view of the cylinder head which shows the structure of a valve lift variable mechanism. It is the perspective view which fractured | ruptured a part which shows the state in which each arm and slider in the valve lift variable mechanism were assembled | attached. It is the perspective view which fractured | ruptured a part which shows each arm in a valve lift variable mechanism. It is a longitudinal cross-sectional view which shows the internal structure of a valve lift variable mechanism. It is a disassembled perspective view of an urging mechanism. FIG. 7A is a bottom view of the spring accommodating space of the housing in the biasing mechanism and its peripheral portion as seen from below, and FIG. 7B is along the line BB in FIG. 7A. It is sectional drawing. It is a figure equivalent to Drawing 7 (a) in the 1st modification. It is a figure equivalent to Drawing 7 (a) in the 2nd modification.

Explanation of symbols

1 engine (internal combustion engine)
9 Intake valve 11a Intake cam 14 Valve lift variable mechanism 17 Input arm (input member)
18 Output arm (output member)
71 Housing (seat member)
72 Spring seat 73 Spring 74 Lifter 75 Seat seat surface 76 First collection groove 77 Second collection groove

Claims (3)

Spring seat surface structure comprising a seat surface member having a seat surface that receives a reaction force from a spring that applies an urging force toward the lifter, and a spring seat interposed between the seat surface of the seat surface member and the spring In
At least one of the seating surface of the seating surface member and the seating surface abutting surface of the spring seat that abuts on the seating surface is subjected to wear powder generated by sliding between the seating surface member and the spring seat. A spring seat surface structure characterized in that a recovery groove for discharging and recovering from between the contact surface and the seat surface abutting surface is provided. In the spring seat surface structure according to claim 1,
The collection groove is formed on the seat surface of the seat member, and is formed continuously from a first collection groove extending radially with respect to the center of the seat surface, and an outer end of the first collection groove, and the wear powder. A spring seat surface structure, comprising: an annular second recovery groove that discharges the outer side of the outer periphery of the spring seat. In the spring seat surface part structure according to claim 1 or 2,
The spring applies an urging force to the variable valve lift mechanism of the internal combustion engine via a lifter,
The variable valve lift mechanism includes an output member for applying a pressing force to the valve in the lift direction, an input member for receiving a pressing force from a cam of the valve operating system, and a pressing force from the cam from the input member to the output member. And a phase difference varying mechanism that varies the relative phase difference between the output member and the input member in the rotational direction, and the spring is in a rotational direction toward the cam with respect to the input member. A spring seat surface structure characterized by applying an urging force of.

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