JP2012163069A - Valve timing changing mechanism - Google Patents

Abstract

There is provided a valve timing changing mechanism capable of suitably suppressing a deviation between a rotating shaft of a camshaft and a rotating shaft of a rotor.
In a valve timing changing mechanism, a rotor 21 is fixed to a camshaft 11 by bolt fastening. A rear bush 28 is provided between the rotor 21 and the camshaft 11. The contact portion between the rear bush 28 and the rotor 21 and the contact portion between the rear bush 28 and the camshaft 11 are each formed into a shape that positions the camshaft 11 in the direction crossing the rotational axis L1 through mutual contact. .
[Selection] Figure 7

Description

  The present invention relates to a variable valve timing mechanism.

  An internal combustion engine is often provided with a valve timing changing mechanism for changing the opening / closing timing (so-called valve timing) of an engine valve such as an intake valve or an exhaust valve. As such a valve timing changing mechanism, a mechanism including a housing connected to a crankshaft via a timing chain or the like and a rotor fixed to the camshaft and disposed in the housing is known (for example, Patent Document 1). In this valve timing changing mechanism, the rotor is fixed to the camshaft by fastening and fixing the bolt to the camshaft with the bolt inserted into the through hole formed in the rotor.

  When the valve timing is changed, the relative rotational phase of the camshaft with respect to the crankshaft is changed by changing the rotational phase of the rotor relative to the rotational phase of the housing.

JP 2009-515090 A

  Here, in the valve timing changing mechanism, when the camshaft rotating shaft and the rotor rotating shaft (specifically, the ideal rotating shaft) are shifted, various functions such as deterioration of the mechanism and generation of noise are caused. There is a risk of inconvenience. Therefore, in order to suppress the occurrence of such inconvenience, it is desirable to fix the rotor to the camshaft so that the deviation of the rotation shafts becomes small.

  In the valve timing changing mechanism, the bolt is positioned with respect to the camshaft at the portion where the bolt is fastened and fixed, and the rotor is positioned with respect to the bolt at the contact portion between the bolt and the rotor. The rotor is positioned with respect to the shaft.

  Usually, when the bolt is fixed to the female screw, a slight gap is formed between the bolt and the female screw. Therefore, in the valve timing changing mechanism, it can be said that when the bolt is fastened and fixed to the camshaft, the bolt may be attached with a slight inclination with respect to the camshaft due to the gap. In the valve timing changing mechanism, the inclination of the bolt mounting angle is not preferable because it causes a deviation between the rotating shaft of the camshaft and the rotating shaft of the rotor.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a valve timing changing mechanism that can suitably suppress the deviation between the rotating shaft of the camshaft and the rotating shaft of the rotor.

In the following, means for achieving the above object and its operational effects will be described.
In the first aspect of the invention, the rotor of the valve timing changing mechanism is fixed to the camshaft by bolt fastening. An intermediary member is provided between the rotor and the camshaft. The contact portion between the intermediary member and the rotor and the contact portion between the intermediary member and the camshaft intersect with the rotation axis of the camshaft through mutual contact. It is formed in a shape that performs positioning in the direction of movement.

  With this configuration, the cam is positioned such that the mediating member is positioned relative to the camshaft at the contact portion between the camshaft and the mediating member, and the rotor is positioned relative to the mediating member at the contact portion between the mediating member and the rotor. The positioning of the rotor relative to the camshaft in the direction intersecting the rotation axis of the shaft can be performed by the mediating member. Therefore, it is not necessary to position the rotor with respect to the camshaft at the contact portion between the bolt and the rotor, and the gap between the bolt and the rotor can be increased as compared with the rotor positioning at the contact portion.

  Therefore, even when the bolt is fixed to the camshaft with a slight inclination when the bolt is fixed to the camshaft, the mounting position of the rotor with respect to the camshaft is prevented from deviating from the ideal position due to this. be able to. Therefore, it is possible to suitably suppress the deviation between the rotating shaft of the camshaft and the rotating shaft of the rotor (specifically, an ideal rotating shaft).

  In the second aspect of the invention, the contact portion between the mediating member and the rotor and the contact portion between the mediating member and the camshaft have the same convex portion having an outer circumferential surface extending in a circular cross section in the rotation axis direction of the camshaft. It will be in the contact state where it fits into the inside of the recessed part extended in a cross-sectional circle shape in a rotating shaft direction.

  According to such a configuration, when the mediating member and the rotor are fixed to the camshaft, the convex portion having the outer peripheral surface having the circular cross section is fitted into the concave portion having the inner peripheral surface having the circular cross section. The positioning of the member and the positioning of the rotor with respect to the mediating member can be respectively performed.

  In the invention described in claim 3, a member having a wall portion extending in a cylindrical shape in the rotation axis direction of the camshaft is employed as the mediating member. Then, the convex portion formed on one of the end portion of the camshaft and the end portion of the rotor is fitted into one end portion of the wall portion in the rotation axis direction, and further, the wall portion The other end in the direction of the rotation axis (specifically, the end opposite to the end where the protrusion is fitted) fits inside the recess formed on the other end of the camshaft and the end of the rotor. The mediating member is disposed so as to be in the state.

  According to such a configuration, the positioning of the mediating member with respect to the camshaft and the positioning of the rotor with respect to the mediating member can be performed together using one cylindrical wall portion. Therefore, the mediating member can have a simple structure as compared with those in which the wall portions for positioning them are provided separately.

  As the valve timing changing mechanism, a hydraulically operated mechanism that operates based on a hydraulic pressure supplied through a hydraulic pressure supply path formed therein is put into practical use. In addition, it has been proposed to provide a check valve for suppressing the backflow of oil in the hydraulic pressure supply path of such a valve timing changing mechanism. As this check valve, it is conceivable to adopt a reed type valve that is simple in structure and inexpensive. When such a lead type check valve is disposed inside the valve timing changing mechanism, it is necessary to secure a space for the operation of the valve body.

  In the invention according to claim 4, the operation chamber for ensuring the operation space of the valve body of the reed valve is defined in the interior of the mediating member. According to such a configuration, it is possible to position the rotor with respect to the camshaft by disposing the intermediary member inside the valve timing changing mechanism, and in addition to the valve body of the lead type check valve. An operating space can be secured.

  The invention according to claim 4 includes a lock mechanism for locking the valve timing at a predetermined timing as in claim 5, and a hydraulic pressure for maintaining the unlocked state by the lock mechanism. It can be applied to a valve timing changing mechanism in which a check valve is provided in the unlocking oil passage for supplying the oil.

BRIEF DESCRIPTION OF THE DRAWINGS The schematic which shows the valve timing change mechanism concerning one Embodiment which actualized this invention with a hydraulic circuit. Sectional drawing of a valve timing change mechanism and its periphery. The perspective view of a rear bush. [A] and [b] A side view of the rear bushing. [A] and [b] Side view of valve plate. Sectional drawing which expands and shows the cross-sectional structure of the periphery of a non-return valve. The exploded perspective view of a cam shaft, a vane, a rear bush, and a valve plate.

Hereinafter, a valve timing changing mechanism according to an embodiment of the present invention will be described.
As shown in FIG. 1, the internal combustion engine 10 is provided with a valve timing changing mechanism 20 for changing the opening / closing timing (valve timing) of an engine valve (for example, an intake valve). As the valve timing changing mechanism 20, a hydraulically operated type in which a hydraulic pressure supply path for supplying hydraulic pressure is formed is adopted.

  The valve timing changing mechanism 20 includes a rotor 21 that is fixed to a camshaft (for example, an intake camshaft [not shown)] of the internal combustion engine 10 by a center bolt 12 and rotates together with the camshaft. The valve timing changing mechanism 20 includes a case 22 that is provided so as to surround the rotor 21 and to which the rotation of the crankshaft (not shown) of the internal combustion engine 10 is transmitted.

  The case 22 is disposed so as to rotate on the same rotation axis as the rotor 21. A plurality of protrusions 23 (three in the present embodiment) are formed on the inner peripheral surface of the case 22 at a predetermined interval in the circumferential direction that protrudes toward the rotation axis L1 of the camshaft. On the other hand, on the outer peripheral surface of the rotor 21, a plurality (three in the present embodiment) of vanes 24 projecting in a direction away from the rotation axis L <b> 1 of the camshaft 11 are positioned between the protrusions 23. It is formed as follows. As a result, a portion located between the protrusions 23 in the case 22 is partitioned into an advance side hydraulic chamber 25 and a retard side hydraulic chamber 26 by the vane 24.

  When the oil is supplied to the advance side hydraulic chamber 25 and the oil is discharged from the retard side hydraulic chamber 26, the rotor 21 rotates in one direction (right rotation direction in FIG. 1) with respect to the case 22, and the camshaft The relative rotational phase with respect to the crankshaft changes to the advance side (front side in the rotational direction). As a result, the valve timing of the engine valve that is driven to open and close by the camshaft changes to the advance side. When oil is supplied to the retarded hydraulic chamber 26 and discharged from the advanced hydraulic chamber 25, the rotor 21 rotates in one direction (the left-rotating direction in FIG. 1) with respect to the case 22, and the camshaft The relative rotational phase with respect to the crankshaft changes to the retard side (rear side in the rotational direction). As a result, the valve timing of the engine valve changes to the retard side.

  The valve timing changing mechanism 20 is provided with two lock mechanisms 13 that fix (lock) the relative rotation of the camshaft 11 at a predetermined timing when the hydraulic pressure is low, such as when the internal combustion engine 10 is started. The lock mechanism 13 includes a lock pin disposed in a vane 24 of the rotor 21 so as to be able to appear and retract and a lock hole formed in the case 22. Then, by inserting the tip end portion of the lock pin into the lock hole, the vane 24 is mechanically fastened to the case 22 and the relative rotation phase of the camshaft with respect to the crankshaft of the internal combustion engine 10 is locked. Further, a release pressure chamber 13 a is defined in a position adjacent to the lock pin inside the vane 24. In the valve timing changing mechanism 20, by supplying oil to the release pressure chamber 13a, the tip end portion of the lock pin escapes from the lock hole, and the lock of the relative rotation phase of the camshaft is released.

  The internal combustion engine 10 is provided with an oil pump 14 for pumping oil to the valve timing changing mechanism 20 and the lock mechanism 13. An oil control valve (specifically, a center bolt 12 having the function of the oil control valve) is provided in the hydraulic circuit that connects the valve timing changing mechanism 20 and the lock mechanism 13 to the oil pump 14. Through the operation control of the oil control valve, the supply / discharge mode of oil to the advance side hydraulic chamber 25 and the retard side hydraulic chamber 26 of the valve timing changing mechanism 20 and the release pressure chamber 13a of the lock mechanism 13 is controlled. The

  The oil control valve is connected to an oil pan 15 for storing oil via a supply oil passage 31. The oil pump 14 is provided in the middle of the supply oil passage 31. The oil pumped by the oil pump 14 is supplied to the oil control valve through the supply oil passage 31. In addition, the oil control valve is connected to the oil pan 15 via the discharge oil passage 32. The oil in the oil control valve can be returned to the oil pan 15 through the drain oil passage 32.

  On the other hand, the oil control valve is connected to the advance side hydraulic chamber 25 of the valve timing changing mechanism 20 via the advance side oil passage 33 and also to the retard side of the mechanism 20 via the retard side oil passage 34. The hydraulic chamber 26 is connected. The oil control valve is connected to the release pressure chamber 13 a of the lock mechanism 13 via the lock oil passage 35.

  The supply oil passage 31 is branched between the oil pump 14 and the oil control valve. One of the branched oil passages (the valve control oil passage 31A) functions as an oil passage for supplying oil to either the advance-side hydraulic chamber 25 or the retard-side hydraulic chamber 26, and the other (locked) The release oil passage 31B) functions as an oil passage for supplying oil to the release pressure chamber 13a.

  A check valve 36A is provided in the valve control oil passage 31A. Since the check valve 36A suppresses the back flow of oil supplied to either the advance side hydraulic chamber 25 or the retard side hydraulic chamber 26, an unnecessary decrease in the pressure of the oil can be suppressed. .

  Further, a check valve 36B is provided in the unlocking oil passage 31B. Since the check valve 36B suppresses the back flow of oil supplied to the unlocking oil passage 31B, an unnecessary decrease in the hydraulic pressure inside the unlocking oil passage 31B is suppressed, and the lock by the lock mechanism 13 is released. The state is suitably maintained. When the operation of the internal combustion engine 10 is stopped, the lock oil passage 35 and the exhaust oil passage 32 are connected by the oil control valve.

Hereinafter, a specific structure of the valve timing changing mechanism 20 will be described.
As shown in FIG. 2, the rotor 21 of the valve timing changing mechanism 20 is fastened and fixed to the camshaft 11 together with the center bolt 12. The center bolt 12 is provided with an oil control valve function in order to improve the operation responsiveness of the valve timing changing mechanism 20 and to suppress oil leakage in a hydraulic path between the mechanism 20 and the oil control valve. What has been adopted is adopted.

  The center bolt 12 includes a substantially cylindrical housing 41. The housing 41 is formed with a plurality of through holes 41a communicating the inside and the outside. When the center bolt 12 is fixed to the camshaft 11, these through holes 41 a are provided with the supply oil passage 31, the advance side oil passage 33, the retard side oil passage 34, and the lock oil passage 35 of the valve timing changing mechanism 20. (Both are shown in FIG. 1).

  A spool 44 for switching the oil supply / discharge mode is provided inside the center bolt 12. The spool 44 is disposed inside the center bolt 12 so as to be movable in the axial direction thereof. An internal passage 44 a is formed inside the spool 44. The internal passage 44a is opened at one end (left side in FIG. 2) of the spool 44, and is communicated with the discharged oil passage 32 (see FIG. 1) through the opening. Further, the spool 44 is formed with a through hole 44b that communicates the inside (internal passage 44a) with the outside. The spool 44 has a structure capable of discharging a specific portion of oil in the center bolt 12 to the discharge oil passage 32 through the internal passage 44a and the through hole 44b. Then, through adjustment of the movement position of the spool 44 in the axial direction, the supply oil passage 31 and the discharge oil passage 32 with respect to the advance side oil passage 33, the retard side oil passage 34, and the lock oil passage 35 (see FIG. 1). It is the structure which can perform switching of the connection aspect of this, and adjustment (opening degree adjustment) of the passage cross-sectional area of the connected oil path.

  The movement of the spool 44 in the axial direction is against a biasing force of the coil spring 45a provided in the housing 41 and biasing the spool 44 in the axial direction (specifically, the left side in FIG. 2). And an actuator 45 that presses the spool 44 in the axial direction (specifically, the right side in FIG. 2). The operation control of the actuator 45 is executed by the electronic control unit 17 including a microcomputer in a manner corresponding to the operating state of the internal combustion engine 10 such as the intake air amount and the engine rotational speed. As a result, the valve timing of the engine valve is adjusted to a timing commensurate with the engine operating state.

  The housing 41 of the center bolt 12 is attached so as to penetrate the rotor 21 of the valve timing changing mechanism 20. At the end of the housing 41 on the camshaft 11 side (right side in FIG. 2), a bolt portion 46 that is screwed to the end of the camshaft 11 is formed. Further, in the vicinity of the end portion of the housing 41 on the side away from the camshaft 11 (left side in FIG. 2), when the bolt portion 46 is screwed to the end portion of the camshaft 11, A flange portion 47 is formed for sandwiching and fixing the rotor 21 therebetween.

  The bolt portion 46 of the center bolt 12 is screwed to the end portion of the camshaft 11, and the end of the rotor 21 is between the end surface of the camshaft 11 and the flange portion 47 of the center bolt 12. In addition, a front bush 27, a rear bush 28, and a valve plate 29 are provided. Specifically, a front bush 27 is provided between the rotor 21 and the flange portion 47. Further, a rear bush 28 and a valve plate 29 are provided between the rotor 21 and the camshaft 11 so that the rear bush 28 and the valve plate 29 are arranged in this order from the rotor 21 side.

  The rotor 21, the front bush 27, the rear bush 28, and the valve plate 29 are formed with holes 21 a, 27 a, 28 a, and 29 a, and the holes 21 a, 27 a, 28 a, and 29 a are formed in the housing 41 of the center bolt 12. Has penetrated. The rotor 21, the front bush 27, the rear bush 28, and the valve plate 29 are arranged such that the end surface of the camshaft 11 and the flange portion of the center bolt 12 when the bolt portion 46 of the center bolt 12 is screwed to the end portion of the camshaft 11. By being sandwiched between the camshaft 47 and the camshaft 11, the camshaft 11 is fixed so as to be integrally rotatable.

  The camshaft 11 supports a sprocket 16 that receives rotation transmission from the crankshaft of the internal combustion engine 10 in a relatively rotatable state. A case 22 of the valve timing changing mechanism 20 is fixed to the sprocket 16. When the rotation of the crankshaft of the internal combustion engine 10 is transmitted to the sprocket 16, the sprocket 16 and the case 22 rotate around the rotation axis L <b> 1 of the camshaft 11. Such rotation of the sprocket 16 and the case 22 is transmitted to the rotor 21 via the oil in the case 22 and then transmitted to the camshaft 11. Therefore, when the rotor 21 of the valve timing changing mechanism 20 is rotated relative to the case 22, the relative rotation phase of the camshaft 11 with respect to the crankshaft changes, and the valve timing of the internal combustion engine 10 changes accordingly. Become.

  In the present embodiment, lead type valves are adopted as the check valves 36A and 36B (see FIG. 1) described above. The valve bodies of these check valves 36A and 36B are formed on the valve plate 29 provided so as to be sandwiched between the camshaft 11 and the rear bush 28. Hereinafter, the structure and operation mode of the check valves 36A and 36B will be described in detail.

  FIG. 3 shows a perspective structure of the rear bush 28, and FIG. 4 shows a side structure of the rear bush 28. In FIG. 4, [b] shows the structure of the rear bush 28 viewed from the direction of arrow A in FIG.

  As shown in FIGS. 3 and 4, the rear bush 28 is formed in a bottomed cylindrical shape including a side wall portion 51 that extends in a cylindrical shape and a bottom wall portion 52 that closes one opening of the cylindrical shape. Yes.

  The bottom wall 52 has the hole 28a, a through hole 53A that forms part of the valve control oil passage 31A (see FIG. 1), and a penetration that forms part of the lock release oil passage 31B (see FIG. 1). A hole 53B is formed. Further, on the inner side surface (the right side in FIG. 4B) of the bottom wall portion 52, a groove portion 54A linearly extending from the through hole 53A as a starting point, and linearly extending from the through hole 53B as a starting point. A groove 54B is formed.

  In addition to the hole 28a and the through holes 53A and 53B, the bottom wall 52 is also formed with two through holes 55 and 56 constituting a part of the hydraulic pressure supply path. Further, an engaging convex portion 57 projects from the inner surface of the bottom wall portion 52.

FIG. 5 shows a side structure of the valve plate 29. In FIG. 5, [b] shows a structure of the valve plate 29 viewed from the direction of arrow B in FIG.
As shown in FIG. 5, the valve plate 29 is formed into a thin plate shape from a metal material. An engagement hole 61 is formed at a position of the valve plate 29 corresponding to the engagement convex portion 57 (see FIG. 4A) of the rear bush 28. When the valve plate 29 is disposed, the engagement hole 61 and the engagement protrusion 57 of the rear bush 28 are engaged with each other, whereby the disposition position of the valve plate 29 becomes a predetermined position.

  The valve plate 29 is formed with the hole 29 a and two through holes 62 and 63. These through holes 62 and 63 are formed at positions communicating with the through holes 55 and 56 of the rear bush 28 by attaching the valve plate 29 to the rear bush 28 and constitute a part of the hydraulic pressure supply path.

The valve plate 29 is formed with valve bodies 64A and 64B having a shape in which the periphery is cut except for a part.
Specifically, the valve body 64A has a valve portion 65A formed in a shape corresponding to the through hole 53A of the rear bush 28 (specifically, a round shape) and a shape corresponding to the groove portion 54A of the rear bush 28 (specifically, And an arm portion 66A having one end connected to the valve portion 65A and the other end connected to the valve plate 29. The valve body 64A is formed at a position covering the through hole 53A and the groove portion 54A of the rear bush 28 by attaching the valve plate 29 to the rear bush 28.

  The valve body 64B has a valve portion 65B formed in a shape corresponding to the through hole 53B of the rear bush 28 (specifically, a round shape) and a shape corresponding to the groove portion 54B of the rear bush 28 (specifically, a rectangular shape). And an arm portion 66B having one end connected to the valve portion 65B and the other end connected to the valve plate 29. The valve body 64B is formed at a position that covers the through hole 53B and the groove 54B of the rear bush 28 by attaching the valve plate 29 to the rear bush 28.

Hereinafter, operation modes of the check valves 36A and 36B will be described.
FIG. 6 shows an enlarged cross-sectional structure around the check valve 36 </ b> A in the valve timing changing mechanism 20. FIG. 6 shows a cross-sectional structure of the valve timing changing mechanism 20 taken along the line CC in FIG. Since the check valves 36A and 36B have the same cross-sectional structure, the cross-sectional structure of the check valve 36B is not shown.

  The check valve 36A operates as follows. As shown in FIG. 6, when oil is pumped from the oil pump 14 and the pressure (hydraulic pressure) of the valve control oil passage 31 </ b> A formed in the camshaft 11 becomes high, the oil pressure causes the valve portion of the valve plate 29 to move. When 65A is pressed, it is deformed as indicated by the alternate long and short dash line in FIG. Thus, the valve control oil passage 31A of the camshaft 11 is communicated with the through hole 53A of the rear bush 28. As a result, the valve control oil passage 31A in the camshaft 11 and the valve control oil passage 31A in the rotor 21 are communicated with each other through the through hole 53A of the rear bush 28. That is, at this time, the check valve 36A is opened.

  On the other hand, if the hydraulic pressure of the valve control oil passage 31A in the camshaft 11 is lowered due to a decrease in the amount of oil pumped from the oil pump 14 or a stop of the oil pumping when the check valve 36A is opened, Since the pressing force acting on the valve body 64A of the valve plate 29 is reduced, the valve body 64A returns to the shape before deformation (the shape indicated by the solid line in the figure) by its elasticity. As a result, the opening on the rear bush 28 side of the valve control oil passage 31A of the camshaft 11 is closed by the valve portion 65A of the valve body 64A. As a result, communication between the valve control oil passage 31A in the camshaft 11 and the valve control oil passage 31A in the rotor 21 is blocked by the valve portion 65A. That is, at this time, the check valve 36A is closed.

  The check valve 36B operates as follows. When the hydraulic pressure of the unlocking oil passage 31B formed in the camshaft 11 is increased by the oil pressure from the oil pump 14, the valve portion 65B of the valve plate 29 is pressed and deformed by the hydraulic pressure, and the camshaft 11 is locked. The release oil passage 31B communicates with the through hole 53B of the rear bush 28. At this time, the unlocking oil passage 31B in the camshaft 11 and the unlocking oil passage 31B in the rotor 21 communicate with each other through the through hole 53B of the rear bush 28, that is, the check valve 36B is opened.

  On the other hand, when the hydraulic pressure of the unlocking oil passage 31B becomes low when the check valve 36B is opened, the pressing force acting on the valve body 64B of the valve plate 29 is reduced by the hydraulic pressure, so that the valve body 64B has its own elasticity. Thus, the shape before deformation is restored, and the opening on the rear bush 28 side of the unlocking oil passage 31B of the camshaft 11 is closed by the valve portion 65B of the valve body 64B. At this time, the communication between the unlocking oil passage 31B in the camshaft 11 and the unlocking oil passage 31B in the rotor 21 is blocked by the valve portion 65B, that is, the check valve 36B is closed.

  When the check valve 36A is opened, the valve body 64A is deformed inside a space (specifically, the through hole 53A and the groove 54A) formed in the rear bush 28 as an operation chamber. When the check valve 36B is opened, the valve body 64B is deformed inside the through hole 53B or the groove 54B formed in the rear bush 28. In the present embodiment, the rear bush 28 is provided for the purpose of securing an operation space for the deformation of the valve body 64A of the check valve 36A and the valve body 64B of the check valve 36B.

  Here, in the valve timing changing mechanism 20, when the rotation axis L1 of the camshaft 11 and the ideal rotation axis of the rotor 21 are shifted, there are various inconveniences such as deterioration of the function of the mechanism 20 and generation of noise. There is a risk of inviting. Therefore, in order to suppress the occurrence of such inconvenience, it is desirable to fix the rotor 21 to the camshaft 11 so that the deviation of the rotation shafts becomes small. The ideal rotation axis of the rotor 21 is a rotation axis that coincides with the rotation axis L1 of the camshaft 11 under the assumption that there is no assembly error or manufacturing tolerance in detail. Called.

  Therefore, in the present embodiment, the contact portion between the rear bush 28 and the rotor 21 and the contact portion between the rear bush 28 and the camshaft 11 are respectively positioned in the direction intersecting the rotation axis L1 of the camshaft 11 through mutual contact. It is formed in the shape that is performed. As a result, the rotor 21 can be positioned with respect to the camshaft 11 by the rear bush 28 provided between the camshaft 11 and the rotor 21, so that the deviation of the rotating shaft can be suppressed.

Hereinafter, a structure for performing such positioning will be described with reference to FIG.
FIG. 7 shows an exploded perspective structure of the camshaft 11, the vane 24, the rear bush 28 and the valve plate 29.

  As shown in FIG. 7, the distal end portion 11a of the camshaft 11 is formed in a columnar shape centered on the rotation axis L1. Further, the tip 11a of the camshaft 11 is formed in a circular shape with a cross section having the same radius.

  As described above, the side wall 51 of the rear bush 28 is formed in a cylindrical shape. In the present embodiment, such a cylindrical side wall 51 has a shape in which both the inner peripheral surface and the outer peripheral surface extend in a circular shape having the same radius, and the center of the side wall 51 matches the ideal rotation axis. It is formed in the shape to do. Note that the ideal rotation axis of the rear bush 28 is a rotation axis that coincides with the rotation axis L1 of the camshaft 11 under the assumption that there is no assembly error or manufacturing tolerance in detail. Called.

  When the valve timing changing mechanism 20 is assembled, the leading end portion 11a of the camshaft 11 is fitted into the side wall portion 51 of the rear bush 28 (the state shown in FIG. 2). In the present embodiment, the radius of the outer peripheral surface of the tip end portion 11a of the camshaft 11 and the radius of the inner peripheral surface of the side wall portion 51 of the rear bush 28 are such that the gap during assembly of the valve timing changing mechanism 20 is reduced. In addition, the front end portion 11a of the camshaft 11 is set so that it fits inside the side wall portion 51 of the rear bush 28 with an appropriate force. In the present embodiment, when the valve timing changing mechanism 20 is assembled, the valve plate 29 is sandwiched between the front end surface of the camshaft 11 and the inner surface of the bottom wall portion 52 of the rear bush 28.

  In the present embodiment, the contact portion between the camshaft 11 and the rear bush 28 has a convex portion (specifically, the tip of the camshaft 11) having an outer peripheral surface extending in a circular cross section in the direction of the rotation axis L1 of the camshaft 11. The part 11a) is in a contact state such that the part 11a) fits inside a recess (specifically, the side wall 51 of the rear bush 28) extending in a circular shape in the direction of the rotation axis L1. For this reason, the outer peripheral surface of the front end portion 11 a of the cam shaft 11 is guided by the inner peripheral surface of the side wall portion 51 of the rear bush 28, and the front end portion 11 a of the cam shaft 11 fits inside the side wall portion 51 of the rear bush 28. In addition, the rear bush 28 is fixed to the camshaft 11. When the rear bush 28 is fixed to the camshaft 11, the rear bush 28 is positioned with respect to the camshaft 11 in the direction intersecting the rotation axis L1 of the camshaft 11. Thus, in the present embodiment, the rotation shaft L1 of the camshaft 11 and the rotation shaft of the rear bush 28 are fitted by fitting the outer peripheral surface of the distal end portion 11a of the camshaft 11 and the inner peripheral surface of the side wall portion 51 of the rear bush 28. Deviation from this can be kept small. In the present embodiment, both the outer peripheral surface of the tip end portion 11a of the camshaft 11 and the inner peripheral surface of the side wall portion 51 of the rear bush 28 are subjected to, for example, grinding in order to match these rotational axes with high accuracy. Therefore, the entire surface is formed with high dimensional accuracy.

  On the other hand, on the surface of the rotor 21 facing the rear bush 28, a concave portion 21b is formed in which the opening peripheral edge of the hole 21a in the same surface is recessed in a circular shape. The recess 21 b is formed in a shape that extends in a circular shape with a cross section centered on the rotation axis of the rotor 21.

  When the valve timing changing mechanism 20 is assembled, the side wall 51 and the bottom wall 52 of the rear bush 28 are fitted into the recess 21b of the rotor 21 (the state shown in FIG. 2). In the present embodiment, the radius of the outer peripheral surface of the side wall 51 of the rear bush 28 and the radius of the inner peripheral surface of the concave portion 21b of the rotor 21 are set so that the gap at the time of assembling the valve timing changing mechanism 20 is small. The side wall portion 51 and the bottom wall portion 52 of the rear bush 28 are set so as to fit into the recess 21b of the rotor 21 with an appropriate force.

  In the present embodiment, the contact portion between the rotor 21 and the rear bush 28 has a convex portion (specifically, a side wall portion of the rear bush 28 having an outer peripheral surface extending in a circular cross section in the direction of the rotation axis L1 of the camshaft 11). 51) is in a contact state in which it fits inside a recess (specifically, recess 21b of the rotor 21) extending in a circular cross section in the direction of the rotation axis L1.

  Therefore, the outer peripheral surface of the side wall 51 of the rear bush 28 is guided by the inner peripheral surface of the recess 21 b of the rotor 21, and the side wall 51 and the bottom wall 52 of the rear bush 28 fit into the recess 21 b of the rotor 21. As described above, the rotor 21 is fixed to the rear bush 28. When the rotor 21 is fixed to the rear bush 28, the rotor 21 is positioned with respect to the rear bush 28 in the direction intersecting the rotation axis of the rear bush 28. As described above, in the present embodiment, the engagement between the inner peripheral surface of the recess 21 b of the rotor 21 and the outer peripheral surface of the side wall portion 51 of the rear bush 28 causes a deviation between the rotation shaft of the rotor 21 and the rotation shaft of the rear bush 28. It will be kept small. In the present embodiment, in order to make the rotation axes coincide with each other with high accuracy, for example, the inner peripheral surface of the concave portion 21b of the rotor 21 and the outer peripheral surface of the side wall portion 51 of the rear bush 28 are both ground. Thus, the entire surface is formed with high dimensional accuracy.

  According to the present embodiment, the rear bush 28 is positioned with respect to the camshaft 11 at the contact portion between the camshaft 11 and the rear bush 28, and at the contact portion between the rear bush 28 and the rotor 21 with respect to the rear bush 28. The positioning of the rotor 21 with respect to the camshaft 11 in the direction intersecting the rotation axis L1 of the camshaft 11 can be performed by the rear bush 28 such that the positioning of the rotor 21 is performed.

  Therefore, it is not necessary to position the rotor 21 with respect to the camshaft 11 at the contact portion between the center bolt 12 and the rotor 21, and the center bolt 12 and the rotor 21 are compared with those in which the rotor 21 is positioned at the contact portion. The gap can be increased.

  Therefore, even if the center bolt 12 is fixed with a slight inclination when the rotor 21 is fixed to the camshaft 11 by bolt fastening, the attachment position of the rotor 21 to the camshaft 11 is ideal due to this. Deviation from the position (specifically, the mounting position under the assumption that there is no assembly error or manufacturing tolerance) can be suppressed.

  Therefore, the deviation between the rotation axis L1 of the camshaft 11 and the rotation axis of the rotor 21 can be suitably suppressed, and the deterioration of the function of the valve timing changing mechanism 20 and the generation of noise due to the deviation can be suppressed.

  In the case where the gap between the center bolt 12 and the rotor 21 is small, when the center bolt 12 is tilted and fixed, the surface pressure at the contact portion between the center bolt 12 and the rotor 21 may become excessively high. In some cases, the center bolt 12 and the rotor 21 may adhere to each other. The valve timing changing mechanism 20 of the present embodiment has a structure in which the fixing strength of the rotor 21 with respect to the camshaft 11 is determined by the fastening force of the center bolt 12. Therefore, if the surface pressure at the contact portion between the center bolt 12 and the rotor 21 becomes excessively high, the center bolt 12 may be supported at the same portion. In such a case, the rotor 21 is fixed to the camshaft 11. It becomes difficult to make the strength appropriate.

  In this respect, in the valve timing changing mechanism 20, since the gap between the center bolt 12 and the rotor 21 can be made relatively large, it is possible to suppress the surface pressure at the contact portion between the center bolt 12 and the rotor 21 from becoming excessively high. Can do. Therefore, the fixing strength of the rotor 21 with respect to the camshaft 11 can be easily set.

  Further, according to the present embodiment, the positioning of the rear bush 28 with respect to the camshaft 11 and the rotor with respect to the rear bush 28 using one cylindrical wall portion (specifically, the side wall portion 51 of the rear bush 28). 21 positioning can be performed together. Therefore, the rear bush 28 can have a simple structure as compared with those in which the wall portions for positioning them are provided separately.

  Furthermore, when the valve timing changing mechanism 20 according to the present embodiment is applied to a valve timing changing mechanism originally provided with a lead type check valve and a rear bush, An existing part (rear bush 28) can be used as an intermediate member provided between the camshaft 11 and the camshaft 11. Therefore, it is possible to suppress the deviation between the rotation axis L1 of the camshaft 11 and the rotation axis of the rotor 21 without increasing the number of new parts.

As described above, according to the present embodiment, the effects described below can be obtained.
(1) Since the rear bush 28 can position the rotor 21 with respect to the camshaft 11 in the direction intersecting the rotation axis L1 of the camshaft 11, the rotation axis L1 of the camshaft 11 and the rotation axis of the rotor 21 The shift can be suitably suppressed.

  (2) When the rear bush 28 and the rotor 21 are fixed to the camshaft 11, the side end 51a of the rear bush 28 in which the tip 11a of the camshaft 11 having a circular outer peripheral surface has a circular inner peripheral surface. The rear bush 28 can be positioned with respect to the camshaft 11 by being fitted inside the camshaft 11. Further, the side wall 51 of the rear bush 28 having the outer peripheral surface having a circular cross section is fitted into the recess 21b of the rotor 21 having the inner peripheral surface having a circular cross section, thereby positioning the rotor 21 with respect to the rear bush 28. be able to.

  (3) Positioning of the rear bush 28 with respect to the camshaft 11 and positioning of the rotor 21 with respect to the rear bush 28 can be performed together by using the side wall portion 51 of the rear bush 28 formed in a cylindrical shape. The rear bush 28 can have a simple structure as compared with the case in which the wall portion for each is provided separately.

  (4) By arranging the rear bush 28 inside the valve timing changing mechanism 20, the rotor 21 can be positioned with respect to the camshaft 11, and in addition, a lead type check valve 36 </ b> A, The operating space for the 36B valve bodies 64A and 64B can be secured.

The embodiment described above may be modified as follows.
In the above embodiment, the outer peripheral surface of the tip end portion 11a of the camshaft 11, the inner peripheral surface and outer peripheral surface of the side wall 51 of the rear bush 28, and the inner peripheral surface of the recess 21b of the rotor 21 are high over the entire surface. It is not necessary to form with only a part of the inner peripheral surface or the outer peripheral surface. Even with such a configuration, the rotation axis L1 of the camshaft 11 and the rotation axis of the rear bush 28 are highly accurate by fitting the outer peripheral surface of the distal end portion 11a of the camshaft 11 and the inner peripheral surface of the side wall 51 of the rear bush 28. Can be matched with. Further, the rotation axis of the rear bush 28 and the rotation axis of the rotor 21 can be matched with high accuracy by fitting the outer peripheral surface of the side wall 51 of the rear bush 28 with the inner peripheral surface of the recess 21b of the rotor 21.

  A recess having an inner peripheral surface with a circular cross section centered on the rotation axis L1 may be formed in the tip 11a of the camshaft 11, and the side wall 51 of the rear bush 28 may be fitted inside the recess. . In addition, a recess having an inner circumferential surface having a circular cross section around the rotation axis of the rear bush 28 is formed in a portion of the rear bush 28 on the rotor 21 side, and the rotor 21 has a circular cross section around the rotation axis. It is also possible to form a convex portion having an outer peripheral surface of the rotor 21 so that the convex portion of the rotor 21 fits inside the concave portion of the rear bush 28. In short, at the contact portion between the camshaft 11 and the rear bush 28 or the contact portion between the rear bush 28 and the rotor 21, one of the members that are in contact with each other is provided with an outer peripheral surface having a circular cross section centered on the rotation axis. What is necessary is just to form the convex part which has, and to form the recessed part extended in the cross-sectional circle shape centering on the rotating shaft on the other. Even in such a configuration, when the rear bush 28 and the rotor 21 are fixed to the camshaft 11, the convex portion having an outer peripheral surface having a circular cross-section is fitted into the concave portion having an inner peripheral surface having a circular cross-section. 11, the rear bush 28 can be positioned, and the rotor 21 can be positioned with respect to the rear bush 28.

  -In the contact portion between the camshaft 11 and the rear bush 28 and the contact portion between the rear bush 28 and the rotor 21, the outer peripheral surface of the protrusion formed on one of the members in contact with each other and the recess formed on the other The inner peripheral surface may be formed in a shape other than a shape extending in a circular cross section. As such a shape, for example, a shape in which grooves or depressions are formed on the outer peripheral surface of the convex portion or the inner peripheral surface of the concave portion, or the outer peripheral surface of the convex portion or the inner peripheral surface of the concave portion has a polygonal cross section in the rotation axis direction. An extending shape can be adopted.

  The valve timing changing mechanism according to the above embodiment is also applied to a valve timing changing mechanism provided with only one lock mechanism or a check valve, or a valve timing changing mechanism provided with no lock mechanism or check valve. be able to.

  DESCRIPTION OF SYMBOLS 10 ... Internal combustion engine, 11 ... Cam shaft, 11a ... Tip part, 12 ... Center bolt, 13 ... Lock mechanism, 13a ... Release pressure chamber, 14 ... Oil pump, 15 ... Oil pan, 16 ... Sprocket, 17 ... Electronic control 20 ... Valve timing changing mechanism, 21 ... Rotor, 21a ... Hole, 21b ... Recess, 22 ... Case, 23 ... Projection, 24 ... Vane, 25 ... Advance side hydraulic chamber, 26 ... Delay side hydraulic chamber, 27 ... Front bush (mediating member), 27a ... Hole, 28 ... Rear bush, 28a ... Hole, 29 ... Valve plate, 29a ... Hole, 31 ... Supply oil passage, 31A ... Valve control oil passage, 31B ... Unlock oil passage 32 ... Exhaust oil passage, 33 ... Advance side oil passage, 34 ... Delay side oil passage, 35 ... Lock oil passage, 36A, 36B ... Check valve, 41 ... Housing, 41a ... Through hole, 44 ... Spool, 44 ... Internal passage, 44b ... Through hole, 45 ... Actuator, 45a ... Coil spring, 46 ... Bolt part, 47 ... Flange part, 51 ... Side wall part, 52 ... Bottom wall part, 53A, 53B ... Through hole, 54A, 54B ... Groove part, 55, 56 ... through hole, 57 ... engagement convex part, 61 ... engagement hole, 62, 63 ... through hole, 64A, 64B ... valve body, 65A, 65B ... valve part, 65A, 65B ... arm part.

Claims (5)

In a valve timing changing mechanism comprising a rotor fixed to a camshaft by bolt fastening,
An intermediary member is provided between the rotor and the camshaft,
The contact portion between the mediation member and the rotor and the contact portion between the mediation member and the camshaft are each formed in a shape that performs positioning in a direction crossing the rotation axis of the camshaft through mutual contact. A valve timing changing mechanism characterized by that. In the valve timing change mechanism according to claim 1,
Each of the contact portions includes a convex portion having an outer peripheral surface extending in a circular cross section in the rotational axis direction of the camshaft, and is fitted in a concave portion extending in a circular cross section in the rotational axis direction. Timing change mechanism. In the valve timing changing mechanism according to claim 2,
The intermediary member has a wall portion that extends in a cylindrical shape in the rotation axis direction, and one end of the camshaft and one end of the rotor are arranged inside one end portion of the wall portion in the rotation axis direction. The other end of the wall portion in the direction of the rotation axis is fitted inside the recess formed on the other end of the camshaft and the end of the rotor. A valve timing changing mechanism characterized by being made. In the valve timing change mechanism according to any one of claims 1 to 3,
The mechanism is a hydraulically operated type in which a hydraulic pressure supply path for supplying hydraulic pressure is formed inside, and a lead type check valve is provided in the hydraulic pressure supply path,
The intermediary member has a valve timing changing mechanism in which an operation chamber for securing an operation space of the valve body of the check valve is defined. In the valve timing changing mechanism according to claim 4,
The mechanism includes a lock mechanism that locks the valve timing at a predetermined timing.
The valve timing changing mechanism according to claim 1, wherein the check valve is provided in an unlocking oil passage that supplies hydraulic pressure for maintaining a state in which the lock by the locking mechanism is released.

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