JPH1193628A - Variable valve timing mechanism and manufacture therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress an adverse influence inducing deterioration of sealability caused by a machining burr to such an extent as not to deteriorate performance of a variable valve timing mechanism of a vane type. SOLUTION: In a variable valve timing mechanism 10, seal grooves 29 are formed at the tips of projections 17 serving as partitions between recesses 16 of a housing 15 and the tips of vanes 14 of an inside rotor 13. A seal member 28 energized by a plate spring 30 is contained inside the seal groove 29. Only a side wall on the side corresponding to an oil pressure chamber 22 on the leading side at the seal groove 29 is chamfered 32.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable valve timing mechanism for varying the valve opening / closing timing of an internal combustion engine according to the operating conditions of the engine, and a method of manufacturing the same.

[0002]

2. Description of the Related Art As is well known, a variable valve timing mechanism of an internal combustion engine is rotationally driven via drive transmission wheels such as a timing pulley, a sprocket, and a driven gear which rotate synchronously with a crankshaft which is an output shaft of the internal combustion engine. This is a mechanism that makes the relative rotation phase of the camshaft variable. With this mechanism, the opening / closing timing of the intake valve or the exhaust valve can be appropriately adjusted according to the operating state of the internal combustion engine such as the load and the number of revolutions. Therefore, it is possible to improve the fuel efficiency, output, emission, and the like of the internal combustion engine over a wide operating range of the engine.

[0003] As one example of such a variable valve timing mechanism, a valve timing adjusting device for an internal combustion engine described in Japanese Patent Application Laid-Open No. 8-121123 is known. A variable valve timing mechanism of the type disclosed in the above publication includes a first rotating body and a second rotating body that have the same axis and can rotate relative to each other. One of these rotating bodies rotates integrally with a drive transmission wheel that is drivingly connected to a crankshaft of the internal combustion engine, and the other rotates integrally with a camshaft. A vane extending in the radial direction of the camshaft is formed on the second rotating body. The vane is disposed in a recess formed in the first rotating body. Further, in the recess, first and second two hydraulic chambers are formed by being partitioned by vanes. By changing the hydraulic pressure in these hydraulic chambers, the two rotating bodies can be relatively rotated. This relative rotation changes the relative rotation phase of the camshaft.
Therefore, it is possible to change the opening / closing timing of the intake valve or the exhaust valve driven to open / close by the camshaft. The variable valve timing mechanism having such a configuration is generally called a “vane type variable valve timing mechanism”.

In such a vane type variable valve timing mechanism, the sealing property of oil in a hydraulic chamber is important. A slight clearance is provided in the sliding contact portion between the first rotating body and the second rotating body to make the relative rotation between the two rotating bodies smooth. Through such clearances, the oil in each of the hydraulic chambers may circulate with each other, thereby impairing the sealing performance. Therefore, a sealing groove is formed at a sliding contact portion between the first rotating body and the second rotating body, that is, a leading end of a vane or a leading end of a convex portion serving as a partition wall between adjacent concave portions, and the like. There is a case where the sealing property is ensured by disposing a sealing member inside. This seal member is pressed against the other rotating body by urging means such as a leaf spring. Thus, the flow of oil through the clearance between the first rotating body and the second rotating body can be restricted.

[0005]

Incidentally, in such a vane type variable valve timing mechanism, the first
High surface accuracy is required on both end surfaces of the rotating body and the second rotating body in the camshaft axis direction in order to ensure sealing performance and smooth relative rotation. In order to satisfy this requirement, these end faces are subjected to finish processing by machining.

However, when such finishing is performed, processing burrs are formed on the outer edge of the end face. The processing burrs may adversely affect the assembly between members, the operation between movable members, and the like. Therefore, it is originally desirable to remove the processing burrs by chamfering. However, in a portion where the first rotating body and the second rotating body are in sliding contact with each other, oil may flow through the cutout portion removed by the chamfering process, and from the viewpoint of ensuring sealing performance, Conventionally, such chamfering has been considered impossible.

[0007] Further, processing burrs resulting from this finishing processing also occur on the side walls of the aforementioned seal grooves. If this is left as it is, the seal member and the seal groove side wall cannot precisely contact due to the processing burr protruding from the seal groove side wall, and the oil flows through the gap to the first and second hydraulic chambers. Will be circulated.

On the other hand, even if the chamfering is performed, the oil in the hydraulic chamber flows through the notch formed by the chamfering, so that the sealing performance eventually deteriorates. Conventionally, the problem of the processing burr treatment has been sufficiently solved as described above.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object thereof is to suppress an adverse effect caused by a reduction in sealing performance due to processing burrs to such an extent that performance of a variable valve timing mechanism is not reduced. And a method of manufacturing the same.

[0010]

In order to achieve the above object, according to the first aspect of the present invention, there is provided a camshaft having the same rotational axis for driving an output shaft of an internal combustion engine and a valve of the engine to open and close. First and second connected to one and the other of the
And the first and second liquid chambers are formed on both sides of the vane by dividing the recess formed in the first rotor with the vane formed in the second rotor. A variable valve timing mechanism that changes the relative rotation phase between the engine output shaft and the camshaft by relatively rotating the first and second rotating bodies based on a hydraulic pressure control for the formed liquid chamber; A sealing groove formed on one of the circumferential sliding surfaces of the first and second rotating bodies, and a radial pressure abutting against the other rotating body in the sealing groove, and a hydraulic pressure from the liquid chamber. And a sealing member that regulates leakage of the first and second liquid chambers, and only the side wall surface corresponding to one of the first and second liquid chambers is chamfered. .

According to the third aspect of the present invention, the first shaft having the same rotation axis and connected to one and the other of the output shaft of the internal combustion engine and one of the camshafts for driving the valves of the engine to open and close.
And a second rotating body, and the first and second rotating bodies are divided by a vane formed in the second rotating body so that first and second rotating bodies are formed on both sides of the vane.
A variable valve that forms a liquid chamber, and changes the relative rotation phase between the engine output shaft and the camshaft by relatively rotating the first and second rotating bodies based on hydraulic pressure control for the formed liquid chamber. As the timing mechanism, the first and second
A seal groove formed on one of the circumferential sliding surfaces of the rotating body,
A method of manufacturing a variable valve timing mechanism, further comprising: a seal member urged radially against the other rotating body in the seal groove to restrict leakage of hydraulic pressure from the liquid chamber. A step of finishing the end face of the rotating body while rotating the rotating body in which the groove is formed in one direction about the axis thereof, and forming a processing burr on only one of both side faces of the seal groove; And a step of chamfering and removing processing burrs generated on one side surface of the seal groove.

In the variable valve timing mechanism having the above-mentioned seal structure, the liquid in the first and second liquid chambers flows through the chamfered portion of the seal groove, so that the response and stability of the mechanism are improved. Performance may be reduced. According to the first or third aspect of the invention, the occurrence of such a problem is limited to only one direction of the relative rotation of the two rotating bodies. Then, by setting the relative rotation direction in which this problem occurs to a direction in which the influence of the decrease in responsiveness and stability is less, a decrease in the performance of the variable valve timing mechanism due to the processing burr processing is suppressed.

According to a second aspect of the present invention, in the variable valve timing mechanism according to the first aspect, the chamfered side wall surface of the seal groove has the first and second side surfaces.
The gist is that the side wall surface corresponds to the liquid chamber on the side where the camshaft is advanced in the liquid chamber.

According to a fourth aspect of the present invention, in the method of manufacturing a variable valve timing mechanism according to the third aspect, one side surface of the seal groove on which the processing burr occurs is formed of the first and second liquid chambers. The gist is that the side surface corresponds to the liquid chamber on the side where the camshaft is advanced.

The rotational torque of the camshaft acts on the variable valve timing mechanism. When the valve opening / closing timing is advanced, it is necessary to resist this rotational torque, so that a relatively large force is required to rotate the two rotating bodies relative to each other. On the other hand, when retarding, relative rotation is possible with relatively small force. According to the second or fourth aspect of the present invention, the occurrence of the trouble due to the chamfering process is limited to when the retard is performed. At the time of retarding, there is a sufficient margin in the response and stability of the variable valve timing mechanism, so that even if the sealing performance is slightly reduced, the function is not reduced enough. Therefore, performance degradation due to the processing burr processing is suppressed.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a variable valve timing mechanism and a method of manufacturing the same according to the present invention will be described in detail.

First, a vane-type variable valve timing mechanism which is the basis of the variable valve timing mechanism to which the present invention is applied will be described with reference to FIG. The variable valve timing mechanism 10 is attached to a tip of a camshaft (not shown). An intake valve or an exhaust valve (hereinafter, simply referred to as a valve) of the internal combustion engine is opened and closed by a cam lobe provided on the camshaft. In addition,
In FIG. 4, the camshaft rotates clockwise.

This camshaft has a center bolt 12
Thus, the internal rotor 13 corresponding to the second rotating body is fastened so as to be integrally rotatable. A housing 15 and a cover 18 are provided so as to cover the outer periphery of the internal rotor 13 and the end face on the tip side of the camshaft. The housing 15 and the cover 18 are plural (four in the figure).
Are connected so as to be integrally rotatable with a driven gear 19 which is drivingly connected to an output shaft of the internal combustion engine. The housing 15, the cover 18, and the driven gear 19 correspond to the first rotating body.

A plurality of (four in the figure) vanes 14 extending in the radial direction of the camshaft are formed on the outer peripheral side surface of the inner rotor 22 so as to project therefrom. Further, a recess 16 for accommodating the vane 14 is formed on the inner peripheral side surface of the housing 15. Note that, in the housing 15, a portion of the partition that partitions between the adjacent concave portions 16 is referred to as a convex portion 17. The tip of the vane 14 is in sliding contact with the inner peripheral side surface of the concave portion 16, and the tip of the convex portion 17 is in sliding contact with the outer peripheral side surface of the internal rotor 13. Therefore, the first rotating body including the housing 15, the cover 18, and the driven gear 19 and the second rotating body
The inner rotor 13 is a rotatable member, and is relatively rotatable about the axis of the camshaft.

The interior of the recess 16 is divided by the vane 14 to form two spaces corresponding to the first and second hydraulic chambers. Here, of these spaces, the rotation direction of the cam shaft viewed from the vane 14, that is, the space 21 on the clockwise direction is defined as a retard hydraulic pressure chamber, and the space 22 on the counterclockwise direction is defined as an advance hydraulic chamber. I will call it.

A retard hydraulic passage 23 and an advance hydraulic passage 24 are connected to the retard hydraulic chamber 21 and the advance hydraulic chamber 22, respectively. The other ends of the retard oil passage 23 and the advance oil passage 24 are connected to an oil control valve 25 (hereinafter simply referred to as OCV 25). The OCV 25 supplies oil pressurized and discharged by the oil pump 26 from the oil pan 27 to one or both of the retard oil passage 23 and the advance oil passage 24 based on an external command. Thus, the retard side hydraulic chamber 2
The hydraulic pressure in the first and advance angle hydraulic chambers 22 is appropriately adjusted. The relative rotation phase of the camshaft with respect to the output shaft of the internal combustion engine is changed based on the control of the hydraulic pressure.

For example, when the valve opening / closing timing is advanced, the hydraulic pressure in the advance hydraulic chamber 22 is set higher than the hydraulic pressure in the retard hydraulic chamber 21. At this time, a clockwise force acts on the vane 14 based on the hydraulic pressure difference between the hydraulic chambers 21 and 22. The internal rotor 13 and the camshaft rotating integrally therewith rotate relative to the first rotating body such as the housing 15 in the clockwise direction based on this force. Thus, the rotational phase of the camshaft is advanced with respect to the output shaft of the internal combustion engine, and the valve opening / closing timing is advanced.

Conversely, when retarding the valve opening / closing timing, the hydraulic pressure in the retard hydraulic chamber 21 is set higher than the hydraulic pressure in the advance hydraulic chamber 22. As before, the internal rotor 13 and the camshaft relatively rotate counterclockwise based on the hydraulic pressure difference between the hydraulic chambers 21 and 22, and the valve opening / closing timing is delayed.

When the valve opening / closing timing is fixed (held), the hydraulic pressures in the retard hydraulic chamber 21 and the advance hydraulic chamber 22 are balanced, and the forces acting on both side surfaces of the vane 14 are balanced. . Thus, by restricting the relative rotation of the internal rotor 13, the valve opening / closing timing is fixed.

However, in practice, a rotational torque acts on the camshaft in a direction opposite to its own rotational direction (counterclockwise direction in FIG. 4). Therefore, when the valve opening / closing timing is fixed, the hydraulic pressure in the advance hydraulic chamber 22 is reduced in order to limit the relative rotation against the rotational torque.
It is necessary to set a little higher than the oil pressure inside.

When the valve opening / closing timing is advanced, the internal rotor 13 is driven against the rotational torque of the camshaft.
Need to be rotated. On the other hand, when retarding, the internal rotor 13 is rotated by being biased by the rotational torque in addition to the hydraulic pressure difference between the hydraulic chambers 21 and 22. Therefore, when the valve opening / closing timing is advanced, the hydraulic pressure difference between the hydraulic chambers 21 and 22 needs to be set larger than when the valve opening / closing timing is retarded.

As described above, the change of the valve opening / closing timing is performed based on the hydraulic control in each of the hydraulic chambers 21 and 22.
Therefore, the sealing property of the oil in each of the hydraulic chambers 21 and 22 is as follows.
This has a significant effect on the responsiveness and stability of the variable valve timing mechanism 10. Further, as described above, the advance side hydraulic chamber 2
The oil pressure in the hydraulic pressure chamber 2 is often set higher than the oil pressure in the retard hydraulic pressure chamber 21, so that the sealing property of the oil in the advance hydraulic pressure chamber 22 is particularly important.

In order to ensure the sealing performance of the hydraulic pressure in each of the hydraulic chambers 21 and 22, the vane 14 and the housing 15
A seal member 28 is provided at the tip of the projection 17. A seal groove 29 having a substantially rectangular cross section is formed at the tip of each of the vane 14 and the convex portion 17. Each seal member 28 is attached in the seal groove 29 by a leaf spring 30 in the radial direction of each rotating body. By being urged, it is pressed against the inner peripheral side surface of the recess 16 or the outer peripheral side surface of the internal rotor 13.

The relative rotation of the internal rotor 13 and the housing 15 is smoothly performed on the sliding contact between the distal end of the vane 14 and the inner peripheral side surface of the concave portion 16 and the distal end of the convex portion 17 and the outer peripheral side surface of the internal rotor 13. Some clearance is provided. Each hydraulic chamber 2 through this clearance
In order to restrict the flow of oil between the first and the second 22, the above-mentioned sealing structure is required.

Next, as one process of a method of manufacturing such a variable valve timing mechanism, a method of finishing both end faces of the internal rotor 13 and the housing 15 in the camshaft axial direction will be described.

FIGS. 5 and 6 show an example of a method of finishing the end face of the housing 15. The housing 15 is fixed by a chuck 41. This chuck 41
The power unit (not shown) is rotatable about the axis of the housing 15.

After holding the housing 15 in this manner, the end surface of the housing 15 is subjected to surface finishing by the cutting tool 40. During this processing, the housing 15 is rotated about its axis by the power unit.
The rotation direction at this time is hereinafter referred to as a work rotation direction. In this way, the finish processing of the entire end face is performed. The same processing is applied to the opposite end face of the housing 15 and both end faces of the internal rotor 13.

When such finishing is performed, the side surfaces of the vanes 14 and the seal grooves 2
In the side wall surface 9, the side surface of the projection 17 in the housing 15, and the side wall surface of the seal groove 29, processing burrs are generated on the side opposite to the work rotation direction of the processed end surface.

FIG. 7 shows the appearance of the tip of the convex portion 17 of the housing 15 immediately after finishing. Here, FIG.
FIG. 7A is an enlarged view of a tip portion of the convex portion 17, and FIG. 7B is a cross-sectional view taken along the line BB 'in FIG. 7A. The protrusion 1 having the seal groove 29 shown in FIG.
In the cross-sectional structure at the tip of 7, the finishing process is performed on the upper end surface in the figure, and the workpiece rotation direction at this time is the left direction in the figure. At this time, the processing burr 31 is formed on the opposite side of the processed end face to the work rotation direction, that is, on the right side of the side surface of the convex portion 17 and the right side of the side wall of the seal groove 29 in FIG.

As described above, if such processing burrs 31 are left as they are, problems often occur. Therefore, the processing burrs 31 are usually removed by chamfering or the like. Normally, when this chamfering process is performed, FIG.
As shown in FIG. 8 (b), a part of (b) is enlarged to show not only the processing burr 31 but also the convex portion 17 or the corner of the sealing groove 29 of the processing object here. A part is removed, and the notch 32 is formed.

Here, of the processing burrs 31 generated by the finishing processing, those on the side surfaces of the vanes 14 or the projections 17 can be removed by the above-described chamfering processing. However, chamfering the processing burr 31 generated on the side wall of the seal groove 29 causes a problem that the sealing performance of the oil in each of the hydraulic chambers 21 and 22 is reduced.

Hereinafter, the reason will be described. FIG.
Indicates a sliding contact portion between the tip of the vane 14 and the concave portion 16. In FIG. 9, the retard side hydraulic chamber 2 is located on the right side of the vane 14.
An advanced hydraulic chamber 22 is formed on the left side of FIG. Here, it is assumed that the notch 32 formed by the chamfering process is formed on the right side of the side wall of the seal groove 29, that is, on the side corresponding to the retard-side hydraulic chamber 21.

Here, consider a case where the hydraulic pressure in the advance hydraulic chamber 22 is set higher than the hydraulic pressure in the retard hydraulic chamber 21 in order to retard or hold the valve opening / closing timing. At this time, the seal member 28 disposed in the seal groove 29 is urged against the concave portion 16 by the urging force of the leaf spring 30, and a difference in oil pressure between the two hydraulic chambers 21 and 22 causes the seal member 29 to be closed. It is also urged against the right side wall in the figure. Therefore, the seal member 28 comes into contact with the side of the seal groove 29 side wall corresponding to the retard side hydraulic chamber 21. Normally, the clearance between the hydraulic chambers 21 and 22 disappears when the seal member 28 comes into contact with the recess 16, and the flow of oil is restricted. However, in the case illustrated in FIG. 9, a gap is formed between the seal member 28 and the right side wall of the seal groove 29 by the notch 32. Therefore, the oil in the advance-side hydraulic chamber 22 having a high hydraulic pressure can be moved to the retard-side hydraulic chamber 21 through this gap in a manner illustrated by an arrow in FIG.

As described above, if the sealing property of the oil in the advance side hydraulic chamber 22 is reduced, the responsiveness and stability of the variable valve timing mechanism 10 are adversely affected. As described above, the hydraulic pressure in the advance hydraulic chamber 22 is set higher than that in the retard hydraulic chamber 21 not only when the valve opening / closing timing is advanced but also when it is fixed. In addition, at the time of advance, it is necessary to relatively rotate the internal rotor 13 against the rotational torque of the camshaft. As described above, the influence on the performance of the variable valve timing mechanism 10 due to the deterioration of the sealing property of the oil in the advance side hydraulic chamber 22 is significant.

Therefore, in the present embodiment, such a problem is solved by employing the structure described below for the variable valve timing mechanism. First, the structure of the variable valve timing mechanism according to the present embodiment and a method of manufacturing the same will be described based on the front structures of the internal rotor 13 and the housing 15 shown in FIG.

In the present embodiment, the above-described internal rotor 1
The work rotation direction is set so that the processing burr 31 is formed on the side wall of the seal groove 29 on the side corresponding to the advance side hydraulic chamber 22 at the time of finishing the end face of the housing 3 and the housing 15.
In other words, when finishing the front end face shown in FIG. 1, the work rotation direction is set to the counterclockwise direction for the internal rotor 13 and the clockwise direction for the housing 15. On the other hand, in the case of the back side, the inner rotor 1
The workpiece rotation direction is set to the clockwise direction for No. 3 and the counterclockwise direction for the housing 15. By setting in this way, processing burrs can be generated only on the side of each seal groove 29 side wall corresponding to the advance side hydraulic chamber 22.

Then, these processing burrs are removed by chamfering. The notches 32 formed by this chamfering work are all on the side corresponding to the advanced hydraulic pressure chamber 22 on the side wall of each seal groove 29.

Here, similarly to the above, the advance side hydraulic chamber 22
Let us consider a case where the oil pressure in the inside is set higher than the oil pressure in the retard-side hydraulic chamber 21. At this time, the sealing member 2
2 and 3, as shown in FIGS. 2 and 3, the spring 8 is urged by a leaf spring 30 to abut against the recess 16 of the housing 15, and based on a difference in oil pressure between the two oil pressure chambers 21 and 22, , Comes into contact with the side wall corresponding to the retard hydraulic pressure chamber 21. However, unlike the above case, according to the above-described structure of the present embodiment, since the notch 32 does not exist at the contact portion between the seal member 28 and the seal groove 29, the oil in the advance-side hydraulic chamber 22 is Sealability is preferably ensured.

However, even in such a structure, during the retarding operation of the valve opening / closing timing in which the hydraulic pressure in the retard hydraulic chamber 21 becomes higher, the retard hydraulic chamber 2 is notched through the notch 32.
1 flows into the advance hydraulic chamber 21, and at this time, the sealing performance of the oil in both hydraulic chambers 21 and 22 is reduced. However, at the time of retarding, the internal rotor 13 and the housing 15 rotate relative to each other while being energized by the rotational torque of the camshaft, in addition to the force due to the hydraulic pressure difference between the two hydraulic chambers 21 and 22, so that such a seal is produced. The effect of the lowering of the performance is extremely small as compared with the case of advance or fixing (holding). Therefore, the performance as the variable valve timing mechanism 10 in terms of responsiveness and stability is sufficiently maintained.

As described in detail above, according to the variable valve timing mechanism and the method of manufacturing the same according to the present embodiment, the following effects can be obtained. The adverse effect caused by the reduction in sealing performance due to the processing burr treatment is suppressed to such an extent that the performance of the variable valve timing mechanism is not reduced, and the responsiveness and stability of the mechanism can be guaranteed.

Since the processing steps required for obtaining such effects are simplified and labor-saving as much as possible, it is possible to improve productivity and reduce production costs. Since the end face is finished while rotating the inner rotor 13 and the housing 15 about these axes, the outer peripheral side face of the inner rotor 13 where it is clear that the sealing property is deteriorated by the processing burr processing is reduced. Recess 1
No processing burr occurs on the inner peripheral side surface of No. 6. Therefore, the location where the problem of the processing burr processing occurs is limited to only the side wall of the seal groove 29, and the reduction of the sealing force caused by the processing burr processing can be overcome in a simpler form.

The present embodiment can be implemented by changing the form as follows. In the present embodiment, the cutting tool 40 is fixed, and the end face finishing is performed while rotating the internal rotor 13 or the housing 15 about the axis thereof. This may be changed so as to perform the finishing while rotating the cutting tool 40 about the axis of the internal rotor 13 or the housing 15 which is the workpiece.

In this embodiment, the leaf spring 30 is used as the urging means for urging the seal member 28.
However, the urging means here is the seal member 2
8 may be any as long as the variable valve timing mechanism 10 can be continuously urged against the other rotating body while the variable valve timing mechanism 10 is operating, such as a coil spring or other elastic body. May apply an urging force based on hydraulic pressure, electricity, magnetic force, or the like.

[0049]

According to the variable valve timing mechanism and the method of manufacturing the same of the present invention, the variable valve timing mechanism is controlled so that the adverse effect caused by the reduced sealing performance due to the processing burr treatment is not reduced to the extent that the function of the mechanism is not reduced. An excellent effect that the responsiveness and stability of the timing mechanism can be ensured can be achieved.

[Brief description of the drawings]

FIG. 1 is a front view showing an embodiment of a variable valve timing mechanism according to the present invention.

FIG. 2 is an enlarged front view showing a structure of a tip end portion of the vane and a peripheral portion thereof according to the embodiment.

FIG. 3 is a perspective view showing a structure of a tip portion of a vane and a peripheral portion thereof.

FIG. 4 is a schematic diagram showing a configuration of a variable valve timing mechanism that is a basis of the embodiment.

FIG. 5 is a perspective view showing a method for finishing an end face of a housing.

FIG. 6 is a front view showing a method of finishing the end face of the housing.

FIG. 7 is a schematic view showing a generation mode of processing burrs.

FIG. 8 is a schematic diagram showing a change of a workpiece before and after chamfering.

FIG. 9 is an enlarged front view showing an example of the structure of the vane tip and its peripheral portion.

FIG. 10 is a perspective view showing a structural example of a vane tip and its peripheral portion.

[Explanation of symbols]

10: Variable valve timing mechanism, 13: Internal rotor (second rotating body), 14: Vane, 15: Housing (first rotating body), 16: concave portion, 17: convex portion, 19: driven gear, 21 ... Retard side hydraulic chamber (hydraulic chamber), 22 ... advance side hydraulic chamber (hydraulic chamber), 28 ... seal member, 29 ... seal groove, 30 ... leaf spring, 31 ... processing burr, 32 ... notch.

Claims (4)

[Claims] A first and a second rotating body connected to one and the other of a camshaft having an identical rotation axis and driving an output shaft of an internal combustion engine and a valve of the engine to open and close; The concave portion formed in the first rotating body is
The first and second rotating bodies are formed on both sides of the vane by partitioning the vanes formed in the rotating body into two, and the first and second rotating bodies are controlled based on the liquid pressure control on the formed liquid chamber. A variable valve timing mechanism for changing the relative rotation phase between the engine output shaft and the camshaft by rotating the seal member relative to each other, wherein a seal groove formed on one of circumferential sliding surfaces of the first and second rotating bodies. And a seal member which is urged against the other rotating body in the seal groove in the radial direction to regulate leakage of hydraulic pressure from the liquid chamber, and wherein the seal groove includes the first and second seal grooves. A variable valve timing mechanism, wherein only a side wall surface corresponding to one of the two liquid chambers is chamfered. 2. The chamfered side wall surface of the seal groove is a side wall surface corresponding to a liquid chamber on the side of the first and second liquid chambers on which the cam shaft is advanced.
3. The variable valve timing mechanism according to 1. And a first and a second rotating body connected to one and the other of a camshaft having the same rotation axis and driving an output shaft of the internal combustion engine and a valve of the engine to open and close. The concave portion formed in the first rotating body is
The first and second rotating bodies are formed on both sides of the vane by partitioning the vanes formed in the rotating body into two, and the first and second rotating bodies are controlled based on the liquid pressure control on the formed liquid chamber. As a variable valve timing mechanism that changes the relative rotation phase between the engine output shaft and the camshaft by relatively rotating a seal groove formed on one of circumferential sliding surfaces of the first and second rotating bodies. A method for manufacturing a variable valve timing mechanism, further comprising: a seal member that is urged radially against the other rotating body in the seal groove to regulate leakage of hydraulic pressure from the liquid chamber. While rotating the rotating body in which the seal groove is formed in one direction around the axis thereof, the end face of the rotating body is finish-processed, and processing burrs are generated only on one of both side surfaces of the seal groove. One of the sealing grooves Manufacturing method for a variable valve timing mechanism characterized in that it comprises a step of machining burrs chamfering removal occurring on the sides, the. 4. A side surface of the seal groove in which the processing burr is formed is a side surface corresponding to a liquid chamber on the side for advancing the camshaft among the first and second liquid chambers. A manufacturing method of the variable valve timing mechanism described in the above.