JP6064780B2 - Variable valve timing mechanism for internal combustion engine - Google Patents

Description

  The present invention relates to a variable valve timing mechanism for an internal combustion engine.

  As shown in Patent Document 1, a variable valve timing mechanism for an internal combustion engine includes a housing that receives rotation transmission from a crankshaft, and a rotation direction with respect to the housing that is provided in the housing and rotates integrally with the camshaft. And a relatively movable rotor. By changing the relative rotational phase of the camshaft with respect to the crankshaft through relative movement of the variable valve timing mechanism with respect to the rotation direction of the rotor, the opening / closing timing of the engine valve that opens and closes as the camshaft rotates ( Valve timing) is variable.

  The variable valve timing mechanism includes a lock mechanism that prohibits or permits relative movement in the rotational direction of the rotor with respect to the housing. When the relative position of the rotor with respect to the rotation direction with respect to the housing becomes the lock position, the lock mechanism causes a lock pin provided on the other side of a hole provided on one of the housing and the rotor to appear and disappear. Then, the relative movement of the rotor with respect to the housing is prohibited by immersing the lock pin in the hole, while the relative movement of the rotor with respect to the housing is permitted by removing the lock pin immersed in the hole from the hole. . In Patent Document 1, the lock mechanism includes a first lock mechanism and a second lock mechanism that allow the lock pin to protrude and retract in the hole at the lock position.

  The variable valve timing mechanism also includes a spring formed in a spiral shape around the camshaft and biasing the rotor in the circumferential direction toward the lock position. One end of the spring is engaged with the rotor, and the other end of the spring is engaged with the housing. Even when the rotor is positioned at the lock position in the rotational direction, the rotor is biased in the circumferential direction by the spring. When the rotor is biased in the circumferential direction with the rotor in the locked position and the lock pin is inserted into the hole, the spring also exerts a resultant force in the radial direction due to the bias on the rotor. .

The valve timing variable mechanism is assembled to the internal combustion engine, for example, as follows.
That is, as a first step, the clearance is adjusted so that the clearance between the lock pin in the valve timing variable mechanism after manufacture is within a proper range when the lock pin is inserted into the hole. Here, when the clearance is smaller than the appropriate range, it is difficult to immerse or withdraw the lock pin, and when the clearance is larger than the appropriate range, the lock pin is immersed in the hole. Sometimes it becomes difficult to properly inhibit the relative movement of the rotor relative to the housing. For this reason, in the variable valve timing mechanism, it is important to set the clearance between the lock pin and the hole in the first lock mechanism and the second lock mechanism within a proper range. The clearance can be adjusted by changing the radial thickness of an annular adjustment bush fitted into the inner peripheral surface of the hole. For this reason, in the first step, the housing and rotor of the variable valve timing mechanism are fixed on a jig, and the adjustment bushing fitted into the inner peripheral surface of the hole under the state is changed to one having a different radial thickness. By appropriate replacement, the clearance between the outer peripheral surface of the lock pin and the inner peripheral surface of the hole (more precisely, the adjustment bush) is adjusted to a value within an appropriate range.

  After performing the first step, the variable valve timing mechanism is removed from the jig. And as a 2nd process, the housing is made into the state which can be displaced to the circumferential direction with respect to the outer peripheral surface of a camshaft, the rotor is displaced to a lock position in the state, and lock | rock of a 1st locking mechanism and a 2nd locking mechanism Immerse the pin into the hole. At this time, the rotor is urged in the circumferential direction by the spring, and a resultant force in the radial direction resulting from the urging acts on the rotor, and the rotor is biased toward the housing in the radial direction by the resultant force. Under this state, the rotor is fixed to the end face of the camshaft. After this fixing, when the lock pins of the first lock mechanism and the second lock mechanism are extracted from the holes, the displacement of the housing in the circumferential direction with respect to the outer peripheral surface of the camshaft is allowed, and the rotor Can move relative to the housing in the rotational direction.

JP 2006-9673 A

  By the way, in the second step, when the rotor is biased in the radial direction with respect to the housing by the resultant force acting in the radial direction with respect to the rotor, depending on the acting direction of the resultant force (the rotor biasing direction with respect to the housing). The variation in the clearance between the lock pin and the hole in the first lock mechanism and the second lock mechanism becomes large.

  Here, when the rotor is displaced in the radial direction with respect to the housing based on the resultant force, when the clearance between the lock pin and the hole is adjusted to a value within an appropriate range in the first step, the rotor is moved in the second step. The relative position in the radial direction of the rotor with respect to the housing shifts when the camshaft is fixed to the end surface of the camshaft. The clearance varies depending on the relative position shift at this time. The magnitude of the variation in the clearance is affected by the direction in which the resultant force acts (the direction in which the rotor is offset with respect to the housing). Therefore, depending on the direction in which the resultant force is applied in the second step, the variation in the clearance between the lock pin and the hole in the first lock mechanism and the second lock mechanism increases.

  If the clearance is deviated from the appropriate range due to the large variation in the clearance, it becomes difficult to insert or remove the lock pin into the hole, or when the lock pin is inserted into the hole, It may be difficult to appropriately prohibit the relative movement of the rotor.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a variable valve timing mechanism for an internal combustion engine that can suppress the clearance between the lock pin and the hole from deviating from an appropriate range.

Hereinafter, means for solving the above-described problems and the effects thereof will be described.
A variable valve timing mechanism for an internal combustion engine that solves the above-described problem is a housing that receives rotation transmission from a crankshaft, and is provided in the housing and can move relative to the housing in the rotational direction while rotating integrally with the camshaft. And a rotor. Further, the variable valve timing mechanism has a first lock provided on the other side of the first hole provided on one of the housing and the rotor when the relative position in the rotation direction of the rotor with respect to the housing becomes the lock position. A first locking mechanism for projecting and retracting the pin is provided. The first lock mechanism regulates relative movement of the rotor relative to the housing in the rotational direction retarded direction by immersing the first lock pin in the first hole. Further, the variable valve timing mechanism has a second lock provided on the other side of the second hole provided on one of the housing and the rotor when the relative position in the rotation direction of the rotor with respect to the housing becomes the lock position. A second locking mechanism for projecting and retracting the pin is also provided. The first lock mechanism restricts relative movement of the rotor relative to the housing toward the advance side in the rotational direction by immersing the second lock pin in the second hole. Further, the variable valve timing mechanism includes a spring formed in a spiral shape around the camshaft and biasing the rotor in the circumferential direction toward the lock position. One end of the spring is engaged with the rotor, and the other end of the spring is engaged with the housing. When the first lock pin is inserted into the first hole and the second lock pin is inserted into the second hole, the biasing force of the spring at the engagement position with respect to the housing acts on the rotor . Further, at this time, based on the urging force between the lock pin and the hole in the lock mechanism that restricts the relative movement of the rotor with respect to the housing in the acting direction of the urging force of the first lock mechanism and the second lock mechanism. Reaction force acts on the rotor . As a result, the resultant force of the urging force and the reaction force acts on the rotor. The direction of action of the resultant force is the first lock pin extending in the axial direction of the cam shaft and the center line of the first hole in the first lock mechanism, and the second lock pin extending in the axial direction of the cam shaft in the second lock mechanism. and to a straight line perpendicular to the center line of the second hole, provoking the angular degree of small value of 0 degrees.

  Here, the assembly of the variable valve timing mechanism to the internal combustion engine is performed, for example, as follows. That is, as a first step, the housing and rotor of the variable valve timing mechanism after manufacture are fixed on a jig, and the first lock pin is inserted into the first hole under the state and the second lock pin is inserted. The clearance is adjusted so that the clearance between the lock pin and the hole when immersed in the second hole is a value within an appropriate range. Further, in the second step after the first step, the housing of the variable valve timing mechanism removed from the jig is made to be displaceable in the circumferential direction with respect to the outer peripheral surface of the camshaft. Displace the rotor to the locked position. Then, the first lock pin of the first lock mechanism is immersed in the first hole, and the second lock pin of the second lock mechanism is immersed in the second hole. At this time, the urging force of the spring acts on the engagement position of the spring with respect to the housing, and the aforementioned urging force is applied between the lock pin and the hole in the lock mechanism that restricts the relative movement of the rotor with respect to the housing in the direction of the urging force. Reaction force against the power acts. As a result, the resultant force of the urging force and the reaction force acts on the rotor, and the rotor is biased in the radial direction with respect to the housing by the resultant force. Then, the rotor is fixed to the end surface of the camshaft under a state where the rotor is offset in the radial direction with respect to the housing.

By the way, in the second step, when the rotor is biased in the radial direction with respect to the housing by the resultant force acting on the rotor, the first force depends on the acting direction of the resultant force (the rotor's biased direction with respect to the housing). The variation in the clearance between the lock pin and the hole in the lock mechanism and the second lock mechanism becomes large. Specifically, as the center line and angles of the direction of application of the resultant force for the straight line perpendicular to the center line of the second lock mechanism of the first lock mechanism is moved away from 0 degrees, the variation of the clearance becomes large. With this in mind, is to angles in the direction of action of the resultant force is zero degrees with respect to a straight line perpendicular to the center line of the center line and the second lock mechanism of the first lock mechanism as described above. Accordingly, the clearance variation above Symbol clearance increases that deviates from the appropriate range is suppressed.

The spring urges the rotor toward the rotation direction toward the lock position, and the first lock pin is immersed in the first hole and the second lock pin is immersed in the second hole. It is conceivable that a reaction force based on the urging force is applied between the second lock pin and the second hole. In this case, so that the center line and angles of the direction of application of the force against the straight line perpendicular to the center line of the second lock mechanism of the first lock mechanism is 0 degree, the engagement position relative to the housing in the spring and the second The positional relationship with the lock mechanism is determined.

  In addition, at least one of the first lock mechanism and the second lock mechanism includes an annular adjustment bush fitted into the inner peripheral surface of the hole, and the adjustment bush has a different radial thickness. It is conceivable that the clearance between the lock pin and the hole can be adjusted by appropriately replacing it. In this case, the deviation from the appropriate range of the clearance due to the large variation in the clearance can be dealt with by appropriately replacing the adjustment bush fitted in the inner peripheral surface of the hole with one having a different radial thickness. Although it is possible to do so, it is necessary to prepare other types of adjusting bushings having different radial thicknesses. However, such a problem can be avoided by suppressing an increase in the variation in the clearance.

1 is a schematic diagram showing a variable valve timing mechanism and a hydraulic circuit for driving the mechanism. Sectional drawing which shows the structure of a locking mechanism. Sectional drawing which shows the structure of a locking mechanism. Sectional drawing which looked at the valve timing variable mechanism of FIG. 1 from the arrow AA direction. The front view which shows the front bush and spring which are provided in a valve timing variable mechanism. The schematic diagram which shows the action direction of the urging | biasing force of the spring which acts on a rotor, the reaction force of the urging | biasing force, and the resultant force of these urging | biasing force and reaction force. The schematic diagram which shows the action direction of the urging | biasing force of the spring which acts on a rotor, the reaction force of the urging | biasing force, and the resultant force of these urging | biasing force and reaction force. The schematic sectional drawing for demonstrating the 1st process of the assembly | attaching method of a valve timing variable mechanism. The schematic sectional drawing for demonstrating the 2nd process of the assembly | attaching method of a valve timing variable mechanism. (A)-(c) is the schematic which shows the generation | occurrence | production aspect of the clearance between the lock pin and the hole in the first lock mechanism and the second lock mechanism. (A)-(c) is the schematic which shows the generation | occurrence | production aspect of the clearance between the lock pin and the hole in the first lock mechanism and the second lock mechanism.

Hereinafter, an embodiment of a variable valve timing mechanism for an internal combustion engine will be described with reference to FIGS.
As shown in FIG. 1, the variable valve timing mechanism 1 for an internal combustion engine includes a rotor 3 fixed by bolts to a camshaft 2 (for example, an intake camshaft) of the engine, and the rotor on the same axis as the camshaft 2. 3 and a housing 4 that is provided so as to surround the crankshaft of the internal combustion engine. A plurality of protrusions 5 projecting toward the axis of the camshaft 2 are formed on the inner peripheral surface of the housing 4 at predetermined intervals in the circumferential direction. A plurality of vanes 6 projecting in a direction away from the axis of the camshaft 2 are formed on the outer peripheral surface of the rotor 3 so as to be positioned between the protrusions 5. As a result, a portion located between the protrusions 5 in the housing 4 is partitioned into an advance side hydraulic chamber 7 and a retard side hydraulic chamber 8 by the vane 6.

  When oil is supplied to the advance side hydraulic chamber 7 and discharged from the retard side hydraulic chamber 8, the rotor 3 moves relative to the housing 4 in the clockwise direction in FIG. The relative rotation phase with respect to the shaft changes to the advance side, and thereby the valve timing of the engine valve (in this example, the intake valve) of the internal combustion engine changes to the advance side. When oil is supplied to the retarded hydraulic chamber 8 and discharged from the advanced hydraulic chamber 7, the rotor 3 moves relative to the housing 4 in the counterclockwise direction in the figure, and the camshaft 2 crankshaft. The relative rotational phase of the internal combustion engine changes to the retard side, whereby the valve timing of the engine valve of the internal combustion engine changes to the retard side.

  The variable valve timing mechanism 1 prohibits relative movement in the rotational direction of the rotor 3 relative to the housing 4 at an intermediate lock position that is a position other than the end of the relative movement range in the rotational direction of the rotor 3 relative to the housing 4. In addition, lock mechanisms 16A and 16B that perform a permission operation for canceling the prohibition and permitting the relative movement are provided. Of these lock mechanisms 16A and 16B, the first lock mechanism 16A is for prohibiting (regulating) the relative movement of the rotor relative to the housing 4 from the intermediate lock position to the retard side in the rotational direction, and the second lock mechanism 16B. Is for prohibiting (regulating) the relative movement of the rotor 4 relative to the housing 4 from the intermediate lock position to the advance side in the rotational direction. The permission operation of the lock mechanisms 16A and 16B is performed by increasing the hydraulic pressure of the release chamber 16a through the supply of oil to the release chamber 16a of the mechanisms 16A and 16B. Further, the prohibiting operation of the lock mechanisms 16A and 16B is performed by lowering the hydraulic pressure of the release chamber 16a through the discharge of oil from the release chamber 16a of the mechanisms 16A and 16B.

  As shown in FIG. 2, the first lock mechanism 16 </ b> A has a lock pin 20 that is inserted into and removed from the hole 19 formed in the housing 4 under the force based on the hydraulic pressure in the release chamber 16 a and the biasing force of the spring 18. Is provided. The hole 19 extends in the axial direction of the camshaft 2 (vertical direction in the drawing), and the lock pin 20 moves in and out of the cam shaft 2 in the direction to realize the insertion and removal of the lock pin 20. An annular adjustment bush 21 for adjusting the clearance between the hole 19 and the lock pin 20 is fitted into the inner peripheral surface of the hole 19. Adjustment of the clearance between the hole 19 and the lock pin 20 is realized by appropriately replacing the adjustment bush 21 with one having a different radial thickness. In the lock mechanism 16A, the clearance here refers to the portion of the rotor 3 on the retard side in the rotational direction between the outer peripheral surface of the lock pin 20 and the inner peripheral surface of the hole 19 (adjustment bush 21). It is the maximum distance. On the other hand, the second lock mechanism 16B does not include the adjusting bush 21 like the first lock mechanism 16A, and the other structure is the same as that of the first lock mechanism 16A. The clearance in the second lock mechanism 16B means the maximum distance between the outer peripheral surface of the lock pin 20 and the inner peripheral surface of the hole 19 at the portion on the rotation direction advance side of the rotor 3.

  Incidentally, the rotor 3 is allowed to be displaced in the rotational direction retarded side with respect to the intermediate lock position by the clearance in the first lock mechanism 16A, while the intermediate lock is in the intermediate lock position by the clearance in the second lock mechanism 16B. It is allowed to be displaced toward the rotational direction advance side with respect to the position. Therefore, when considering both the first lock mechanism 16A and the second lock mechanism 16B, the substantial clearance with respect to the hole 19 of the lock pin 20 is the same as that of the first lock mechanism 16A and the second lock mechanism 16B. This is the total value of the above clearance.

  In the lock mechanisms 16A and 16B, the oil pressure in the release chamber 16a is reduced by discharging the oil from the release chamber 16a while the rotor 3 is moved to the intermediate lock position and the lock pin 20 and the hole 19 are aligned. By reducing the force based on the force, the prohibiting operation of immersing the lock pin 20 into the hole 19 by the biasing force of the spring 18 is performed. Further, in the lock mechanisms 16A and 16B, the spring 18 is increased by increasing the force based on the hydraulic pressure in the release chamber 16a through supply of oil to the release chamber 16a with the lock pin 20 immersed in the hole 19. As shown in FIG. 3, the permission operation for extracting the lock pin 20 from the hole 19 is performed against the urging force. Of the lock mechanisms 16A and 16B, the hole 19 in the first lock mechanism 16A and the lock pin 20 that is inserted into the hole 19 are the first for restricting the relative movement of the rotor 3 relative to the rotation direction of the rotor 3 relative to the housing 4. It functions as one hole and a first lock pin. Further, the hole 19 in the second lock mechanism 16B and the lock pin 20 that is inserted into the hole 19 are provided with a second hole and a second lock for restricting relative movement of the rotor 3 relative to the housing 4 in the rotational direction advance side. Functions as a pin.

  The rotor 3 (vane 6) of the lock mechanisms 16A and 16B has an advance side hydraulic chamber 7 and a retard side hydraulic chamber when the prohibiting operation of the lock mechanisms 16A and 16B is performed (FIG. 2). A communication path 17 that communicates with 8 is formed. As shown in FIG. 3, the communication path 17 is cut off by the lock pin 20 when the permission operation of the lock mechanisms 16 </ b> A and 16 </ b> B is completed.

  As shown in FIG. 1, oil supply / discharge to the advance side hydraulic chamber 7 and retard side hydraulic chamber 8 of the variable valve timing mechanism 1 and oil supply / discharge to the release chamber 16a of the lock mechanisms 16A, 16B are as follows. This is performed through a plurality of oil passages that constitute a hydraulic circuit that connects the variable valve timing mechanism 1 and the lock mechanisms 16A and 16B to the oil pump 9. An oil control valve 10 is provided in the middle of the plurality of oil passages in the hydraulic circuit to change the oil supply / discharge mode with respect to the variable valve timing mechanism 1 and the lock mechanisms 16A and 16B.

  The oil control valve 10 is connected to the oil pump 9 via a supply passage 11 and is connected to an oil pan 12 for storing oil pumped up by the oil pump 9 via a discharge passage 13. . The supply passage 11 is branched into two on the downstream side of the oil pump 9 and is connected to the oil control valve 10 at two points. The oil control valve 10 is connected to the advance side hydraulic chamber 7 of the variable valve timing mechanism 1 via the advance side oil passage 14 and is retarded to the retard side hydraulic chamber 8 of the mechanism 1. The side oil passage 15 is connected. Further, the oil control valve 10 is connected to a release chamber 16a of lock mechanisms 16A and 16B provided in the variable valve timing mechanism 1 via a release oil passage 22.

  Then, by using the oil control valve 10 to change the oil supply / discharge mode with respect to the variable valve timing mechanism 1 and the lock mechanisms 16A and 16B, the relative rotation phase of the camshaft 2 with respect to the crankshaft is controlled by the operation of the variable valve timing mechanism 1. Or the lock mechanism 16A, 16B is prohibited or permitted.

Next, how the variable valve timing mechanism 1 is attached to the camshaft 2 will be described in detail.
As shown in FIG. 4, the rotor 3 of the variable valve timing mechanism 1 is tightened by screwing a bolt 23 penetrating the rotor 3 into a screw hole 32 formed in the camshaft 2, thereby tightening the end of the camshaft 2. It is fixed and can rotate integrally with the camshaft 2. On the other hand, the housing 4 surrounding the rotor 3 is supported by the outer peripheral surface of the camshaft 2 so as to be relatively rotatable around the camshaft 2. The housing 4 includes a front plate 24 and a rear plate 25 that sandwich the rotor 3 from both sides in the thickness direction (the left-right direction in the figure), a side ring 26 that is located on the outer periphery of the rotor 3 and surrounds the entire outer periphery of the rotor 3. The front plate 24, the rear plate 25, and the side ring 26 are connected so as to be integrally rotatable.

  Further, between the head 23 a of the bolt 23 and the rotor 3, a front bush 27 fixed to the rotor 3 and rotating integrally with the rotor 3 is sandwiched. A spiral spring 28 around the camshaft 2 is provided around the front bush 27. The spring 28 is used to urge the rotor 3 toward the advance side toward the intermediate lock position in the circumferential direction when the rotor 3 relative to the housing 4 moves relative to the retard side relative to the intermediate lock position. It is.

  As shown in FIG. 5, one end 28 a of the spring 28, specifically, an end 28 a near the center CL of the camshaft 2 is engaged with a notch 31 formed in the front bush 27. Since the front bush 27 is fixed to the rotor 3, the end 28 a of the spring 28 at this time is engaged with the rotor 3 via the front bush 27. The other end 28 b of the spring 28, specifically, the end 28 b away from the center CL of the camshaft 2 is attached to the pin 29 or the front bush 27 fixed to the housing 4 (precisely, the front plate 24). The pin 30 can be engaged with the fixed pin 30.

  Here, when the rotor 3 and the front bush 27 are moved relative to the housing 4 toward the retard side (in the direction of the arrow Y1) with respect to the intermediate lock position, the end portion 28b of the spring 28 is engaged with the pin 29 of the front plate 24. On the other hand, with the engagement, the pin 30 of the front bush 27 is separated from the end portion 28b in the arrow Y1 direction. As a result, the front bush 27 (rotor 3) is urged toward the intermediate lock position by the spring 28 toward the rotational direction advance side of the rotor 3. Further, when the rotor 3 and the front bush 27 move relative to the housing 4 toward the advance side (in the direction of the arrow Y2) from the intermediate lock position, the end portion 28b of the spring 28 engages with the pin 30 of the front bush 27. With this engagement, the end portion 28b is separated from the pin 29 of the front plate 24 in the arrow Y2 direction. At this time, the front bush 27 (the rotor 3) is not biased toward the intermediate lock position by the spring 28.

  Accordingly, when the rotor 3 and the front bush 27 move relative to the housing 4 relative to the intermediate lock position, or when they move relative to the retard side (in the direction of the arrow Y1) relative to the intermediate position, the end portion 28b of the spring 28 is moved to the pin 29. Engage with. Since the pin 29 is formed on the front plate 24, the end portion 28 b is engaged with the front plate 24 (housing 4) via the pin 29 at this time, and the rotor 3 is intermediately locked by the spring 28 accordingly. The rotor 3 is biased toward the advance side in the rotational direction toward the position. Even when the rotor 3 is located at the intermediate lock position and the lock pins 20 of the first lock mechanism 16A (FIGS. 2 and 3) and the second lock mechanism 16B are immersed in the holes 19, the rotor 3 is not affected by the spring. It is urged by 28 in the circumferential direction. Furthermore, when the spring 28 urges the rotor 3 in the circumferential direction in this way, a resultant force in the radial direction caused by the urging is also applied to the rotor 3.

Specifically, as described above, the urging force F1 of the spring 28 that urges the rotor 3 in the circumferential direction is between the end portion 28b of the spring 28 and the pin 29 fixed to the housing 4 shown in FIG. It acts on the position of engagement with the housing 4. The acting direction of the urging force F1 at this time is the direction shown in FIG. Further, when the urging force F1 is applied to the rotor 3, the second lock mechanism 16B that restricts the relative movement of the rotor 3 with respect to the housing 4 in the direction in which the urging force F1 is applied (precisely, the lock pin 20 and the hole 19 The reaction force F2 based on the urging force F1 acts in the direction shown in FIG. The resultant force F3 of the urging force F1 and the reaction force F2 acts on the rotor 3 in the radial direction as shown in FIG. The center line of the lock pin 20 and the hole 19 extending in the axial direction of the camshaft 2 in the first lock mechanism 16A, and the center line of the lock pin 20 and the hole 19 extending in the axial direction of the camshaft 2 in the second lock mechanism 16B. The resultant force F3 is inclined with respect to the straight line L1 perpendicular to the line. Angles θ of the resultant force for the straight line L1 F3 is a small value of less than the set value determined in advance.

Incidentally, the acting direction of the resultant force F3 with respect to the rotor 3 is determined by the positional relationship between the engagement position of the spring 28 with respect to the housing 4 and the second lock mechanism 16B. If the engagement position of the spring 28 with respect to the housing 4 (the position where the biasing force F1 acts) is set to the position shown in FIG. 7, the biasing force F1 acts in the direction shown in FIG. The resultant force F3 of the force F1 and the reaction force F2 also acts on the rotor 3 in the direction corresponding to the engagement position. Thus, in this embodiment, the positional relationship between the engaging position and the second lock mechanism 16B to the housing 4 in the spring 28, the corners of the direction of action of the resultant force against the straight line L1 F3 shown in FIG. 6 theta is of less than the set value It is set to be a small value. Incidentally, it is preferable to set here at the optimum value determined in advance by experiments or the like as the setting value to be used (e.g., 45 degrees), it is preferable that the upper Symbol angles θ and 0 degrees.

Next, a method for assembling the variable valve timing mechanism 1 to the internal combustion engine will be described.
In this assembling method, as a first step, the clearance between the lock mechanism 20 when the lock pin 20 of the lock mechanism 16A, 16B in the valve timing variable mechanism 1 after manufacture is immersed in the hole 19 is set to a value within an appropriate range. The clearance is adjusted. The clearance here is the substantial clearance described above when both the first lock mechanism 16A and the second lock mechanism 16B are taken into consideration.

  As shown in FIG. 8, the rear plate 25 of the housing 4 is inserted into the outer peripheral surface of the columnar jig 33, and the outer surface of the cylindrical portion 33 a formed on the end surface of the jig 33 with the rotor 3 in the housing 4. Insert into. Further, the temporary assembly bolt 35 is inserted into the cylindrical portion 33 a and screwed into the screw hole 34 of the jig 33, and the housing 4 and the rotor 3 are fixed on the jig 33 by tightening the bolt 35. In this state, by appropriately replacing the adjustment bush 21 fitted in the inner peripheral surface of the hole 19 of the first lock mechanism 16A with one having a different radial thickness, the substantial clearance becomes a value within an appropriate range. Thus, the clearance between the outer peripheral surface of the lock pin 20 and the inner peripheral surface of the hole 19 (more precisely, the adjustment bush 21) is adjusted. Incidentally, the appropriate range of the substantial clearance means that the lock pin 20 of the lock mechanisms 16A and 16B can be accurately inserted and removed from the hole 19, and the lock pin 20 can be removed from the hole. 19 is a range in which relative movement in the rotation direction of the rotor 3 with respect to the housing 4 can be appropriately prohibited when immersed in the housing 19. Note that the replacement of the adjustment bush 21 described above can be realized by temporarily removing the rear plate 25 in the housing 4 from the side ring 26.

  After performing the said 1st process, the valve timing variable mechanism 1 is removed from the jig | tool 33 by loosening the temporary assembly volt | bolt 35. FIG. Thereafter, as a second step, the valve timing variable mechanism 1 is assembled to the camshaft 2 of the internal combustion engine.

  Specifically, as shown in FIG. 9, the rear plate 25 of the housing 4 is inserted into the outer peripheral surface of the camshaft 2, and the bolt 23 penetrating the rotor 3 is screwed into the screw hole 32 of the camshaft 2, thereby changing the valve timing. 1 is temporarily assembled to the camshaft 2. Under this state, the displacement of the housing 4 in the axial direction relative to the camshaft 2 is restricted, and the displacement of the housing 4 in the circumferential direction of the camshaft 2 is allowed. At this time, the rotor 3 can be displaced in the radial direction with respect to the housing 4 by the gap between the bolt 23 and the rotor 3, and the housing with respect to the camshaft 2 by the gap between the camshaft 2 and the housing 4. 4 can be displaced in the radial direction. Thereafter, the rotor 3 is displaced to the intermediate lock position so that the rotor 3 is biased in the circumferential direction by the spring 28, and the lock pins 20 of the first lock mechanism 16 </ b> A and the second lock mechanism 16 </ b> B are inserted into the holes 19. At this time, the rotor 3 is biased in the circumferential direction by the spring 28, and a resultant force F3 in the radial direction due to the biasing acts on the rotor 3. The resultant force F3 causes the rotor 3 to be displaced in the radial direction (arrow Y4 direction) with respect to the housing 4. Then, the rotor 3 is fixed to the end surface of the camshaft 2 by tightening the bolts 23 in a state where the rotor 3 is displaced in the radial direction with respect to the housing 4. Thereby, the rotor 3 can rotate integrally with the camshaft 2, and the rotor 3 can move relative to the housing 4 that can be displaced in the circumferential direction with respect to the outer peripheral surface of the camshaft 2 in the rotational direction.

Next, the operation of the variable valve timing mechanism 1 will be described.
In the second step, when the rotor 3 is biased to the housing 4 in the radial direction by the resultant force F3 acting in the radial direction with respect to the rotor 3, the acting direction of the resultant force F3 (the piece of the rotor 3 with respect to the housing 4) Depending on the approach direction, the substantial clearance variation between the lock pin 20 and the hole 19 increases. Specifically, as the center line and angles of the direction of application of the resultant force F3 against the straight line L1 perpendicular to the center line of the second lock mechanism 16B of the first lock mechanism 16A theta away from 0 degrees in the range up to 0 to 90 degrees The substantial clearance variation is increased.

  10A to 10C show the clearance between the lock pin 20 and the hole 19 in the first lock mechanism 16A when the lock pin 20 moves relative to the hole 19 in the direction orthogonal to the straight line L1 (in the drawing). C1) and the generation of the clearance (C2 in the figure) between the lock pin 20 and the hole 19 in the second lock mechanism 16B. In the figure, (a) shows a state in which the lock pin 20 and the hole 19 are coaxially located, (b) shows a state in which the lock pin 20 has moved relative to the hole 19 on the right side in the figure, (C) shows a state in which the lock pin 20 has moved relative to the hole 19 to the left in the drawing.

  On the other hand, FIGS. 11A to 11C show the clearance C1 and the second lock mechanism in the first lock mechanism 16A when the lock pin 20 moves relative to the hole 19 in the direction parallel to the straight line L1. The generation | occurrence | production aspect of the said clearance C2 in 16B is shown. In the figure, (a) shows a state in which the lock pin 20 and the hole 19 are coaxially located, (b) shows a state in which the lock pin 20 has moved relative to the hole 19 in the upper side in the figure, (C) shows a state in which the lock pin 20 has moved relative to the hole 19 downward in the figure.

  Here, the rotor 3 is allowed to be displaced toward the rotation direction retard side with respect to the intermediate lock position by the clearance C1 in the first lock mechanism 16A, while the clearance C2 in the second lock mechanism 16B. Therefore, it is allowed to be displaced toward the advance side in the rotational direction with respect to the intermediate lock position. Therefore, the substantial clearance with respect to the hole 19 of the lock pin 20 when considering both the first lock mechanism 16A and the second lock mechanism 16B is the sum of the clearance C1 and the clearance C2 as described above. It becomes.

  As shown in FIGS. 10A to 10C, when the lock pin 20 moves relative to the hole 19 in the direction orthogonal to the straight line L1, the clearance C1 of the first lock mechanism 16A and the second lock mechanism 16B The clearance C2 expands or contracts together based on a relative position in a direction (left and right direction in the figure) perpendicular to the straight line L1 with respect to the hole 19 of the lock pin 20. That is, as shown in FIG. 10B, when the lock pin 20 is moved relative to the hole 19 on the right side in the figure, both the clearance C1 and the clearance C2 become large. As a result, the substantial clearance (“C1 + C2”) considering both the first lock mechanism 16A and the second lock mechanism 16B is increased. Further, as shown in FIG. 10C, when the lock pin 20 is moved relative to the hole 19 to the left side in the drawing, both the clearance C1 and the clearance C2 become small. Thereby, the substantial clearance (“C1 + C2”) considering both the first lock mechanism 16A and the second lock mechanism 16B is reduced. Therefore, when the lock pin 20 moves relative to the hole 19 in the direction orthogonal to the straight line L1, it is inevitable that the substantial clearance variation due to the relative movement increases.

  On the other hand, as shown in FIGS. 11A to 11C, when the lock pin 20 moves relative to the hole 19 in a direction parallel to the straight line L1, the clearance C1 and the second lock of the first lock mechanism 16A are used. The clearance C2 of the mechanism 16B changes alternately based on a relative position in a direction (vertical direction in the drawing) parallel to the straight line L1 with respect to the hole 19 of the lock pin 20. That is, as shown in FIG. 11B, in the state where the lock pin 20 is moved relative to the hole 19 in the upper side in the figure, the clearance C1 is increased while the clearance C2 is decreased. Thereby, the change of the said substantial clearance ("C1 + C2") which considered both the 1st lock mechanism 16A and the 2nd lock mechanism 16B is suppressed. Further, as shown in FIG. 11C, in the state where the lock pin 20 is moved relative to the hole 19 in the lower side in the figure, the clearance C1 is reduced while the clearance C2 is increased. Thereby, the change of the said substantial clearance ("C1 + C2") which considered both the 1st lock mechanism 16A and the 2nd lock mechanism 16B is suppressed. Therefore, when the lock pin 20 moves relative to the hole 19 in a direction parallel to the straight line L1, the substantial clearance variation due to the relative movement is suppressed to a small value.

From the above, in the second step, angles θ are 0 ° direction of action of the resultant force for linearly L1 (biasing direction of the rotor 3 relative to the housing 4) 90 degrees away from the (parallel to the straight line L1) ( The closer to the straight line L1, the greater the variation in the substantial clearance. With this in mind, the variable valve timing mechanism on SL angles in 1 theta is such a small value of less than a predetermined set value. Thus, the upper Symbol angles θ away from 0 degrees is suppressed, thus the substantial clearance increasing dispersion becomes in the clearance is to be prevented from deviating from the proper range.

According to the embodiment described in detail above, the following effects can be obtained.
(1) In the variable valve timing mechanism 1, since a small value of angles θ is less than the set value in the acting direction of the resultant force F3 against the straight line L1 (biasing direction of the rotor 3 relative to the housing 4), the angles θ are Leaving from 0 degrees can be suppressed. As a result, it is possible to suppress a substantial variation in clearance due to the execution of the second step and to prevent the clearance from deviating from an appropriate range.

  (2) If the adjustment bush 21 fitted in the inner peripheral surface of the hole 19 is appropriately replaced with one having a different radial thickness in the second step, the substantial clearance is deviated from the appropriate range. Therefore, it is necessary to prepare another type of adjusting bush 21 having a different radial thickness. However, the occurrence of such a problem can be avoided by suppressing an increase in the substantial clearance variation as described in (1) above.

In addition, the said embodiment can also be changed as follows, for example.
The spring 28 may urge the rotor 3 toward the retarded angle toward the intermediate lock position. In this case, the biasing force F1 is applied by the first lock mechanism 16A (more precisely, between the lock pin 20 and the hole 19) that restricts the relative movement of the rotor 3 with respect to the housing 4 in the direction of the biasing force F1 of the spring 28. The reaction force F2 based on this acts, and the resultant force F3 of the urging force F1 and the reaction force F2 acts on the rotor 3. Then, as the angle of the direction of action of the resultant force F3 against the straight line L1 theta is less than the set value, the positional relationship between the engaging position and the first lock mechanism 16A to the housing 4 in the spring 28 is determined.

  Instead of adjusting the clearance between the lock pin 20 and the hole 19 in the first lock mechanism 16A by the adjustment bush 21, the adjustment bushing is used to adjust the clearance between the lock pin 20 and the hole 19 in the second lock mechanism 16B. 21 may be performed. Further, the clearance between the lock pin 20 and the hole 19 by the adjustment bush 21 may be adjusted by both the first lock mechanism 16A and the second lock mechanism 16B.

-Although 45 degree | times was illustrated as said setting value, you may change this value suitably.
In the lock mechanisms 16A and 16B, the positional relationship between the lock pin 20 and the hole 19 may be reversed.

  The engine valve whose valve timing is variable by the valve timing variable mechanism may be an exhaust valve. In this case, the rotor of the valve timing variable mechanism is urged toward the most advanced position by the spring of the variable valve timing mechanism, and the relative movement of the rotor with respect to the housing is prohibited by the lock mechanism with the most advanced position as the lock position. Is called.

  DESCRIPTION OF SYMBOLS 1 ... Valve timing variable mechanism, 2 ... Cam shaft, 3 ... Rotor, 4 ... Housing, 5 ... Projection, 6 ... Vane, 7 ... Advance side hydraulic chamber, 8 ... Delay side hydraulic chamber, 9 ... Oil pump, DESCRIPTION OF SYMBOLS 10 ... Oil control valve, 11 ... Supply passage, 12 ... Oil pan, 13 ... Discharge passage, 14 ... Advance angle side oil passage, 15 ... Delay angle side oil passage, 16A ... First lock mechanism, 16B ... Second lock mechanism 16a ... Release chamber, 17 ... Communication path, 18 ... Spring, 19 ... Hole, 20 ... Lock pin, 21 ... Adjustment bushing, 22 ... Release oil passage, 23 ... Bolt, 23a ... Head, 24 ... Front plate, 25 ... rear plate, 26 ... side ring, 27 ... front bush, 28 ... spring, 28a ... end, 28b ... end, 29 ... pin, 30 ... pin, 31 ... notch, 32 ... screw hole, 33 ... Jig, 33a ... Circle Part, 34 ... screw hole, 35 ... provisional-assembly bolt.

Claims (3)

A housing that receives rotation transmission from the crankshaft, a rotor that is provided in the housing and rotates relative to the housing while rotating integrally with the camshaft;
When the relative position in the rotational direction of the rotor with respect to the housing is a locked position, the housing and the first hole provided in one of the housing and the rotor and extending in the axial direction of the camshaft A first lock pin provided on the other of the rotors can be moved in and out, and the first lock pin is inserted into the first hole so that the rotor relative to the housing in the rotation direction is retarded. A first lock mechanism for restricting movement;
When the relative position in the rotational direction of the rotor with respect to the housing is a locked position, the housing and the second hole provided in one of the housing and the rotor and extending in the axial direction of the camshaft A second lock pin provided on the other of the rotors can be moved in and out, and the second lock pin is inserted into the second hole so as to be relative to the housing in the rotational direction of the rotor. A second lock mechanism for restricting movement;
The rotor is formed in a spiral shape with the camshaft as the center, and one end is engaged with the rotor and the other end is engaged with the housing, thereby locking the rotor. A spring biasing in the circumferential direction toward the position;
In a valve timing variable mechanism of an internal combustion engine comprising:
When the first lock pin is immersed in the first hole and the second lock pin is immersed in the second hole, the urging force of the spring at the engagement position with respect to the housing is applied to the rotor. On the other hand, among the first lock mechanism and the second lock mechanism, the attachment between the lock pin and the hole in the lock mechanism that restricts the relative movement of the rotor with respect to the housing in the direction of application of the biasing force. by the reaction force based on the forces acting on the rotor, the resultant force of those urging force and the reaction force acts on the said rotor,
The first lock pin extending in the axial direction of the cam shaft in the first lock mechanism and the center line of the first hole, and the second lock pin extending in the axial direction of the cam shaft in the second lock mechanism; the relative straight line perpendicular to the center line of the second hole, a variable valve timing mechanism for an internal combustion engine, characterized in that the direction of action of the angles of the pre-Symbol force to 0 °. The spring urges the rotor toward the rotation position toward the lock position, and the first lock pin is inserted into the first hole and the second lock pin is the first lock. A reaction force based on the urging force is applied between the second lock pin and the second hole when immersed in two holes;
As the angle of the direction of action of the resultant force to said straight line is 0 degrees, for an internal combustion engine according to claim 1, wherein the positional relationship between the engaging position and the second lock mechanism relative to the housing in the spring are determined Valve timing variable mechanism.   At least one of the first lock mechanism and the second lock mechanism includes an annular adjustment bush fitted into the inner peripheral surface of the hole, and the adjustment bush has a different radial thickness. 3. The variable valve timing mechanism for an internal combustion engine according to claim 1 or 2, wherein the clearance between the lock pin and the hole can be adjusted by exchanging it with one.