JP4506059B2 - Valve timing control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a valve opening / closing timing control device for controlling the opening / closing timing of intake and exhaust valves of an internal combustion engine.
[0002]
[Prior art]
As a conventional valve opening / closing timing control device, there is a technique disclosed in Japanese Patent Laid-Open No. 11-13432. This is a rotary member for opening and closing a valve assembled to a cylinder head of an internal combustion engine, a rotation transmission member that can rotate relative to the rotation member and rotate integrally therewith, and a protrusion formed on the rotation transmission member and in sliding contact with the peripheral surface of the rotation member. , A vane provided on the rotating member, a stopper formed on the protrusion and in contact with the vane, and formed between the rotating member and the rotation transmitting member, and is divided into an advance angle chamber and a retard angle chamber by the vane. A fluid pressure chamber, advancing and retarding fluid passages for supplying and discharging fluid to and from the advancing chamber and retarding chamber, an advancing chamber, an advancing fluid passage, and a retarding chamber, respectively. A retarding fluid passage is communicated with each other, and a groove is formed on the sliding contact surface of the rotation transmitting member and is formed at a circumferential end of the protrusion.
[0003]
However, in the above prior art, the area formed in sliding contact with the peripheral surface of the rotating member is reduced by the groove formed at the circumferential end of the protrusion. For this reason, the surface pressure generated on the sliding contact surface of the protrusion increases due to the load generated by the tension of the timing chain that transmits the rotational power from the drive shaft of the internal combustion engine to the sprocket formed on the outer periphery of the rotation transmission member, and wear. Is concerned.
[0004]
Further, due to the groove formed at the circumferential end of the protrusion, the position of the surface of the stopper that comes into contact with the vane becomes the radially outward portion, and the load generated on the vane at the time of contact with the vane becomes the moment load. For this reason, there are concerns about vane breakage and vane groove wear.
[0005]
[Problems to be solved by the invention]
Therefore, the present invention has a technical problem in the valve timing control device to reduce the surface pressure generated on the sliding contact surface of the protrusion of the rotation transmission member and the moment load generated on the vane.
[0006]
In order to solve the technical problem described above, the means taken in the invention of claim 1 includes a rotor attached to a camshaft supported on a cylinder head of an internal combustion engine, and a sheath rotatably mounted on the rotor. A housing having a protrusion slidably contacting the peripheral surface of the rotor, a sprocket provided on the outer periphery of the housing, a vane provided on the rotor and extending radially outward of the rotor, and between the housing and the rotor A fluid pressure chamber formed by the vane and divided into an advance chamber and a retard chamber, and an advance and retard fluid passage for supplying and discharging fluid to and from the advance chamber and the retard chamber, respectively. And the advance chamber, the advance fluid passage, and the retard chamber and the retard fluid passage, respectively, at the circumferential end of the projection on the sliding contact surface with the rotor It is formed In the valve timing control apparatus including bets, the sprocket with provided one axial end of the housing, the axial length of said sprockets is set to be shorter than the length in the axial direction of said housing, said groove The circumferential end of the projection corresponding to the sprocket with respect to the axial direction of the housing is formed on the axial end surface of the projection. A corner portion extending along the radially inner side of the housing and slidingly contacting the rotor is provided, and one end side in the axial direction of the groove is closed by the corner portion.
[0007]
According to this means, the sprocket is provided on one end side in the axial direction of the housing, the length in the axial direction of the sprocket is set shorter than the length in the axial direction of the housing , and the groove is formed from the other end side in the axial direction of the housing. An angle formed along the axial direction and extending along the radial inner side of the housing at one end surface in the axial direction of the projection at the circumferential end of the projection corresponding to the sprocket with respect to the axial direction of the housing and slidingly contacting the rotor Since the one end side in the axial direction of the groove is closed by the corner portion, the area of the sliding contact surface of the projection of the housing can be increased, so that the surface pressure can be reduced.
[0008]
In order to solve the above technical problem, the measure taken in the invention of claim 2 is that the groove is formed in the stopper.
[0009]
According to this means, since the position of the surface of the stopper that contacts the vane can be the vane base, the load at the time of contact can be changed from the moment load to the shear load.
[0010]
More preferably, the two opposing grooves for the fluid pressure chamber are each formed by concentric arcs.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below.
[0012]
The valve opening / closing timing control device shown in FIGS. 1 and 2 mainly includes a valve opening / closing rotor 20 that is integrally assembled with the tip of a camshaft 10 that is rotatably supported by a cylinder head 100 of an internal combustion engine. The housing 30 is mounted on the rotor 20 so as to be relatively rotatable within a predetermined range, the front plate 40 , the rear plate 50 , the timing sprocket (sprocket) 31 integrally provided on the outer periphery of the housing 30, and the rotor 20. The four vanes 70 and the lock key 80 assembled to the housing 30 are included.
[0013]
The camshaft 10 has a well-known cam (not shown) for opening and closing an intake valve (not shown), and an advance angle passage 11 and a retard angle passage 12 extending in the axial direction of the camshaft 10 are provided therein. The advance passage is connected to the first connection port 201 of the switching valve 200 through the radial passage 71 provided in the camshaft, the annular groove 14 provided in the cylinder head 100 and the connection passage 16. The retard passage 12 is connected to the second connection port 202 of the switching valve 200 through the radial passage 72 provided in the camshaft, the annular groove 13 provided in the camshaft, and the connection passage 15 provided in the cylinder head 100. ing. The switching valve 200 is a known valve that moves the spool 204 against a spring (not shown) by energizing the solenoid 203. When not energized, the supply port 206 connected to the oil pump 205 driven by the internal combustion engine communicates with the second port 202, and the first port 201 communicates with the discharge port 207. When energized, the supply port 206 communicates with the first port 201 and the second connection port 202 communicates with the discharge port 207 as shown in FIG. Therefore, hydraulic oil (hydraulic pressure) is supplied to the retard passage 12 when the switching valve 200 is not energized, and hydraulic oil (hydraulic pressure) is supplied to the advance passage 11 when energized. The switching valve 200 is controlled by changing a duty ratio which is a ratio of energization and non-energization per unit time. For example, when the duty ratio is controlled at 50%, the first and second ports 201 and 202 and the supply and discharge ports 206 and 207 are not in communication with each other.
[0014]
The rotor 20 is integrally fixed to the camshaft 10 by a single mounting bolt 91, and includes four vane grooves 21, a lock key receiving groove 22, and four advance / retard passages 23 extending in the radial direction, 24 and a passage 25 extending in the circumferential direction on the outer peripheral surface of the rotor 20. Each of the four vanes 70 is attached to the vane groove 21 so as to be movable in the radial direction, and a leaf spring 73 is disposed between the bottom portion of the vane groove 21 and the bottom surface of the vane 70, and the tip of the vane 70 is disposed on the vane groove 21. It is in pressure contact with the inner peripheral surface of the housing. In the state shown in FIG. 2, that is, when the relative position of the rotor 20 and the housing 30 is synchronized at a predetermined relative phase (most retarded angle position), the head of the lock key 80 is sunk into the receiving groove 22 by a predetermined amount. The hydraulic oil from the advance passage 23 is supplied to the receiving groove 22.
[0015]
The housing 30 is assembled to the outer periphery of the rotor 20 so as to be relatively rotatable within a predetermined angle range. An annular front plate 40 and rear plate 50 are joined to both sides of the housing 30 and are integrally connected by four connecting bolts 92. A sprocket 31 is integrally formed on the outer periphery of the axial end of the housing 30 to which the rear plate 50 is joined.
[0016]
Four protrusions 33 are formed on the inner periphery of the housing 30 in the circumferential direction, and a fluid pressure chamber R0 is formed between the protrusions 33 adjacent in the circumferential direction. These protrusions 33 are in contact with the outer peripheral surface of the rotor 20 to form an inner peripheral surface on which the housing 30 is rotatably supported by the rotor 20. Further, two of the protrusions 33 are formed with stoppers 33c and 33d that abut against the two vanes 70a and 70b of the vane 70, respectively.
[0017]
As shown in FIG. 3, the protrusion 33 has a groove 33a and a corner 33b following the groove 33a in the axial direction of the housing 30 at both ends in the circumferential direction. The groove 33a has a circular arc-shaped cross section in which the inner peripheral side, the circumferential end face side, and the front plate 40 side of the protrusion 33 are opened. The two grooves 33a facing each fluid pressure chamber R0 can have a circular arc shape with a concentric cross section. Therefore, the two grooves 33a can be processed simultaneously by a single rotary blade.
[0018]
The corner 33 b is disposed at a position facing the sprocket 31 in the axial direction of the housing 30, and the width in the housing axial direction is preferably equal to or greater than the width of the sprocket 31. 4 shows the protrusion 33 as viewed in FIG. 3A, and the inner peripheral surface of the protrusion 33 has a convex shape and is formed of a pressure receiving surface 37 and a pressure receiving surface 38 of the corner 33b. For this reason, the area of the pressure receiving surface 38 is expanded with respect to the pressure receiving surface 37 of the prior art, and the surface pressure due to the load received from the timing chain on the inner peripheral surface of the protrusion 33 can be reduced.
[0019]
FIG. 5 shows a view of the protrusion 33 in FIG. The end faces of the stoppers 33c and 33d are also formed from the end face 40 with the end face 39 as shown in FIG. For this reason, the position which contacts the vanes 70a and 70b can be the end surface 39 and the end surface 40. For this reason, when the stoppers 33c and 33d of the protrusion 33 and the vanes 70a and 70b come into contact with each other, the load acting on the vanes 70a and 70b acts on the vane base from the moment load acting on the position from the vane base to the end face 39. It can be a shear load.
[0020]
When the area in contact with the vanes 70a and 70b is equal to that of the prior art, the groove 33a on the circumferential end face side of the protrusion 33 can be enlarged in the radial direction. In other words, since the cross-sectional area of the groove 33a forming the oil passage can be enlarged, the amount of hydraulic oil supplied from the advance passage 23 to the advance chamber R1 and from the retard passage 24 to the retard chamber R2 is increased. Can do. In addition, as shown in FIG. 7, the protrusion 33 can also be set as the structure which forms the corner | angular part 33b in the axial direction both ends, and forms the groove | channel 33a between them. One of the inner peripheral surfaces of the protrusion 33 has a retraction groove 34 that accommodates the lock key 80 and a spring 81 that communicates with the retraction groove 34 and biases the lock key 80 radially inward. A receiving groove 35 is formed.
[0021]
Each vane 70 includes a fluid pressure chamber R0 formed between the plates 40 and 50 in the axial direction, between the housing 30 and the rotor 20 in the radial direction, and between the adjacent protrusions 33 in the circumferential direction. The chamber is divided into an advance chamber R1 and a retard chamber R2. The relative rotation amount between the rotor 20 and the housing 30 depends on the circumferential width (angle) of the fluid pressure chamber R0. On the most retarded angle side shown in FIG. 2, the vane 70 a comes into contact with the end face 40 of the stopper 33 c of the protrusion 33 on the base side where the rotor 20 is attached. Further, on the most advanced angle side, the vane 70 b comes into contact with the end surface 40 of the stopper 33 d of the protrusion 33 on the base side attached to the rotor 20. Thereby, on the most retarded angle side, as shown in FIG. 8, the load F generated by the fluctuation torque of the camshaft 10 and the drive torque of the valve opening / closing timing control device acts as a shear load on the vane base of the vane 70a. On the other hand, as shown in FIG. 9, the vane 70 a comes into contact with the radially outer portion of the stopper 33 c of the protrusion 33, and a moment load in which the load F acts at a length 1 from the vane base acts on the vane base. Compared with the vanes of the valve opening / closing timing control device, the strength of the vanes and the strength of the vane grooves can be improved. Note that the load F acts as a shear load on the vane base of the vane 70b also on the most advanced side.
[0022]
The operation of the valve timing control apparatus of the present embodiment configured as described above will be described.
[0023]
When the internal combustion engine is stopped, the oil pump 205 is stopped and the switching valve 200 is in a non-energized state, so that hydraulic fluid (hydraulic pressure) is not supplied to the fluid pressure chamber R0. For this reason, the rotor 20 and the housing 30 are synchronized at the most retarded position as shown in FIG. Here, the head of the lock key 80 is fitted into the receiving groove 22 of the inner rotor 20 by a predetermined amount, and the relative rotation between the rotor 20 and the housing 30 is restricted at the most retarded position.
[0024]
When the internal combustion engine is started, the valve opening / closing timing control device receives the fluctuation torque of the camshaft and the driving torque of the valve opening / closing timing control device in the state of FIG. 2 at the most retarded position. These torques act on the stopper 33 c composed of the end surface 39 and the end surface 40 of the protrusion 33 of the housing 30 and the vane 70 a attached to the rotor 20.
[0025]
In order to advance the valve opening / closing timing in accordance with the operating conditions of the internal combustion engine, the duty ratio for energizing the switching valve 200 is increased and the position of the spool 204 is switched. Accordingly, the hydraulic oil (hydraulic pressure) supplied from the oil pump 205 is supplied to the advance chamber R1 through the connection passage 16, the advance passage 11 and the passage 23. Further, it is supplied to the receiving groove 22 through the passage 23, and is supplied to the advance angle chamber R1 through the passage 25. On the other hand, the hydraulic oil (hydraulic pressure) in the retarding chamber R2 is discharged from the discharge port of the switching valve 200 via the passage 24, the retarding passage 12, and the connection passage 15. At this time, the lock key 80 moves against the spring 81, the head of the lock key 80 comes out of the receiving groove 22, the rotor 20 and the housing 30 are unlocked, and the rotor 20 rotates integrally with the camshaft 10. Each vane 70 rotates relative to the housing 30 and the plates 40, 50 in the advance side (clockwise). This relative rotation can extend from the most retarded state shown in FIG. 2 to the most advanced angle state (not shown).
[0026]
In the most advanced angle state, the vane 70b attached to the rotor 20 contacts the stopper 33d formed by the end surface 39 and the end surface 40 of the protrusion 33 of the housing 30. At this time, the vane 70b receives the fluctuation torque of the camshaft and the driving torque of the valve timing control device.
[0027]
On the other hand, in order to retard the valve opening / closing timing, the duty ratio for energizing the switching valve 200 is decreased and the position of the spool 204 is switched. Accordingly, hydraulic oil (hydraulic pressure) supplied from the oil pump 205 via the switching valve 200 is supplied to the retarding chamber R2 through the connection passage 15, the retarding passage 12 and the passage 24, and the intermediate stop groove 33c. Is done. On the other hand, the hydraulic oil (hydraulic pressure) in the advance angle chamber R1 is discharged through the passage 23, the retard passage 11, the connection passage 16, and the switching valve.
[0028]
In a state where the lock key 80 is removed from the receiving groove 22, the hydraulic oil can be supplied to the retarding chamber R <b> 2 if the duty ratio energizing the switching valve 200 is reduced. Therefore, the rotor 20 and the vanes 70 are rotated relative to the housing 30 and the plates 40 and 50 in the retarding direction (counterclockwise) from the most advanced angle state (not shown) to the most retarded angle state shown in FIG. Can do.
[0029]
During operation of the internal combustion engine, rotational power is transmitted in the clockwise direction in FIG. 2 from the crankshaft (not shown) of the internal combustion engine to the sprocket 31 of the valve opening / closing timing control device via the crank sprocket and the timing chain. The housing 30 supports the outer peripheral surface of the rotor 20 on the inner peripheral surface of the projection 33 formed by the pressure receiving surface 37 and the pressure receiving surface 38 so as to be relatively rotatable, and receives a load generated by the tension of the timing chain.
[0030]
In addition, although this embodiment forms the protrusion 33 in the 1st rotation member which consists of the housing 30, embodiment of the valve opening / closing timing control apparatus which formed the protrusion 33 in the 2nd rotation member which consists of the rotor 20 is embodiment. It can also be.
[0031]
Further, in the present embodiment, since the reduction of the surface pressure of the rotation support surface of the protrusion 33 of the housing 30 can be reduced, the material is replaced with aluminum to reduce the weight.
[0032]
FIG. 6 shows another embodiment of the present invention. This is because the moment load generated when the relative rotation of the housing 30 and the rotor 20 is restricted can be reduced, so that the material can be replaced with a sintered material and the outer peripheral portion of the protrusion of the housing can be thinned. Can be made lighter. Other parts are the same as those in the first embodiment.
[0033]
【The invention's effect】
As described above, according to the invention of claim 1, the housing 30 can increase the area of the inner peripheral surface (rotating bearing surface) of the protrusion 33 that receives the load by the rotational power transmitted to the sprocket 31. The surface pressure of the inner peripheral surface 33 can be reduced, and the reliability of the support portion can be improved.
[0034]
According to the invention of claim 2, the fluctuation torque of the camshaft and the driving torque of the valve opening / closing timing control device act as a shear load on the base of the vane 70 attached to the internal rotor 20. For this reason, the strength of the vane and the vane groove can be improved as compared with the vane of the conventional valve timing control device acting as a moment load, so that the reliability can be improved and the oil passage can be expanded. As a result, the amount of hydraulic oil increases, and the performance of the valve timing control device can be improved.
[0035]
According to the invention of claim 3, since the grooves 33a at both ends in the circumferential direction of the protrusion 33 are concentric arcs, the grooves 33a can be simultaneously processed when formed by machining and plastic working.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a valve timing control apparatus according to an embodiment of the present invention.
FIG. 2 is a front view of the valve opening / closing timing control device in the most retarded state with the front plate 40 removed in FIG.
FIG. 3 is a detailed view from the front of the housing 30 of the valve opening / closing timing control device.
FIG. 4 is a front view of the protrusion 33 of the housing 30 of the valve opening / closing timing control device as viewed from A. FIG.
FIG. 5 is a front view of the housing 30 of the valve opening / closing timing control device as viewed from B. FIG.
FIG. 6 is a front view of the most retarded angle state of the valve timing control apparatus according to another embodiment of the present invention.
FIG. 7 is a front view of the housing 30 of the valve timing control apparatus according to another embodiment of the present invention as viewed from the B side.
FIG. 8 is a detailed view of the vane portion in the most retarded state of the present invention.
FIG. 9 is a detailed view of a vane portion in the most retarded state of the prior art.
[Explanation of symbols]
20 ... Rotor 23 ... Advance passage (advance fluid passage)
24 .. retarding passage (retarding fluid passage)
30 ... Housing 33 ... Projection 33a ... Groove 33b ... Corner 33c ... Stopper 33d ... Stopper 70, 70a, 70b ... Vane R0 ... Fluid pressure chamber R1, ..Advance chamber R2 ... Delay chamber

Claims (3)

A rotor attached to a camshaft supported by a cylinder head of an internal combustion engine;
A housing that is externally rotatably supported with the rotor and has a protrusion that is in sliding contact with the circumferential surface of the rotor;
A sprocket provided on the outer periphery of the housing;
A vane provided in the rotor and extending radially outward of the rotor;
A fluid pressure chamber formed between the housing and the rotor and partitioned by the vane into an advance chamber and a retard chamber;
Advancing and retarding fluid passages for supplying and discharging fluid to and from the advancing and retarding chambers, respectively
The advance chamber, the advance fluid passage, the retard chamber, and the retard fluid passage communicate with each other, and are formed at circumferential ends of the protrusions on the sliding surface with the rotor. A valve opening / closing timing control device comprising a groove,
The sprocket is provided on one end side in the axial direction of the housing, and the axial length of the sprocket is set shorter than the axial length of the housing,
The groove is formed along the axial direction from the other axial end side of the housing,
A circumferential end portion of the protrusion corresponding to the sprocket with respect to the axial direction of the housing extends along the radially inner side of the housing to one axial end surface of the protrusion and is in sliding contact with the rotor. Is provided,
A valve opening / closing timing control device characterized in that one end side in the axial direction of the groove is closed by the corner portion. The valve opening / closing timing control device according to claim 1, wherein the groove is formed in the stopper. The valve opening / closing timing control device according to claim 1 or 2, wherein two opposing grooves are formed by concentric arcs for the fluid pressure chamber.

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