JP3821254B2 - Valve timing control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a valve opening / closing timing control device used for controlling the opening / closing timing of an intake valve or an exhaust valve in a valve operating apparatus for an internal combustion engine.
[0002]
[Prior art]
As one of the valve opening / closing timing control devices of this type, a predetermined range is provided on a rotary shaft for valve opening / closing (consisting of a camshaft and an internal rotor provided integrally therewith) that is rotatably assembled to a cylinder head of an internal combustion engine. A rotation transmission member which is externally mounted so as to be relatively rotatable and to which rotational power from a crankshaft is transmitted, and phase conversion means which is provided between the rotation transmission member and the rotation shaft so as to be movable at least to the rotation transmission member; A fluid pressure chamber formed between the rotation transmission member and the rotation shaft and divided into an advance oil chamber and a retard oil chamber by the phase conversion means; the advance oil chamber and the retard oil chamber; A first connection port connected to the oil chamber; a discharge port connected to the discharge passage; and a supply port connected to a hydraulic pressure supply source; To supply and discharge hydraulic fluid to the chamber. And a hydraulic fluid supply / discharge means comprising a switching valve for selectively communicating the second connection port with at least the supply port and the discharge port, or the discharge port and the supply port. No. 92504 and Japanese Utility Model Laid-Open No. 2-50105.
[0003]
[Problems to be solved by the invention]
In the valve opening / closing timing control device disclosed in each of the above-mentioned publications, the rotation is transmitted at the most retarded angle (or at the most advanced angle) at which the volume of the retarded oil chamber (or the advanced oil chamber) becomes maximum. In order to maintain the phase between the member and the rotating shaft, the hydraulic oil is supplied to the retarding oil chamber (or the advance oil chamber), and the vane retarding oil chamber side surface (or the advance oil chamber side) Hydraulic pressure is applied to the side surface, and the advance oil chamber (or retard oil chamber) communicates with the discharge port. By the way, fluctuating torque acts on the camshaft of the internal combustion engine, which is the rotating shaft, and when this fluctuating torque is large, the fluctuating torque overcomes the rotational force by the hydraulic pressure acting on the vane, and the most retarded angle or most advanced angle May not be maintained. In order to avoid this state, in the conventional valve timing control apparatus described above, the pressure receiving area of the vane is increased, or the operating hydraulic pressure supplied from the hydraulic pressure supply source is increased to increase the rotational force against the fluctuation torque. In addition to the increase, there is a problem that the manufacturing cost of the valve opening / closing timing control device is increased and increased, or the hydraulic supply source is increased.
[0004]
Therefore, in the valve opening / closing timing control device according to the present invention, it is possible to reliably maintain a desired phase at the most retarded angle and the most advanced angle without causing an increase in manufacturing cost and an increase in size. Let it be an issue.
[0005]
[Means for Solving the Problems]
The technical means of the present invention devised to solve the above-described problems includes a rotation transmission member that is mounted on a rotary shaft for opening and closing a valve so as to be relatively rotatable within a predetermined range, and between the rotation transmission member and the rotary shaft. A phase conversion means provided to be movable relative to at least one of the rotation transmission member and the rotation shaft, and an advance oil chamber formed by the phase conversion means formed between the rotation transmission member and the rotation shaft. A fluid pressure chamber divided into a retard angle oil chamber, first and second connection ports connected to the advance angle oil chamber and the retard angle oil chamber, a discharge port connected to the discharge passage, and a hydraulic pressure At least a supply port connected to a supply source, and at least the first and second connection ports to supply and discharge hydraulic oil to and from the advance angle oil chamber and the retard angle oil chamber. Or in the discharge port and supply port In a valve opening / closing timing control device used for controlling the opening / closing timing of an intake valve or an exhaust valve of an internal combustion engine, comprising a hydraulic oil supply / discharge means comprising a switching valve that selectively communicates with each other. That is, a one-way valve that allows only the flow of hydraulic oil from the discharge port to the discharge passage is interposed between the discharge port and the discharge passage.
[0006]
In the above-described means, the phase converting means may be constituted by a vane attached to one of the rotating shaft or the rotation transmitting member.
[0007]
According to the above means, at the most retarded angle (or at the most advanced angle), the hydraulic oil is supplied to the retarded oil chamber (or the advanced oil chamber), while the one-way valve is used for the advanced angle. A sealed space is formed from the oil chamber (or the retarding oil chamber) to the one-way valve via the discharge port of the switching valve. As a result, the volume of the retard oil chamber (advance oil chamber) is decreased and the volume of the advance oil chamber (retard oil chamber) is increased at the most retarded angle (or most advanced angle). When fluctuating torque is applied to the rotating shaft so as to move the phase conversion means to the side, the fluctuating torque is maintained by the reaction force from the retard oil chamber (advance oil chamber) by the positive hydraulic pressure, and advances. From the corner oil chamber (retarding oil chamber), the phase is stabilized without increasing the pressure receiving area of the phase conversion means or increasing the hydraulic oil pressure to be supplied. Retained.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of a valve timing control apparatus according to the present invention will be described with reference to the drawings.
[0009]
1 and 2, the valve timing control apparatus includes a camshaft 10 that is rotatably supported by a cylinder head 70 of the internal combustion engine and an internal rotor that is integrally assembled at the front end (right end in FIG. 1) thereof. Rotating shaft for valve opening / closing constituted by 20 and the outer periphery of the outer rotor 30, the front plate 40, the rear plate 50, and the rear plate 50 that are externally rotatably mounted on the camshaft 10 and the inner rotor 20 within a predetermined range. By a rotation transmission member constituted by the timing sprocket 51 provided in the motor, a phase conversion means constituted by five vanes 60 assembled to the internal rotor 20, a hydraulic oil supply / discharge means constituted by a switching valve 90 and the like. It is configured. As is well known, the timing sprocket 51 is configured such that rotational power is transmitted in the clockwise direction in FIG. 2 from a crankshaft (not shown) via a crank sprocket and a timing chain.
[0010]
The camshaft 10 has a known cam 11 that opens and closes an intake valve, and an advance angle passage 12 and a retard angle passage 13 that extend in the axial direction of the camshaft 10 are provided therein. The advance passage 12 is connected to the first connection port 91 a of the switching valve 90 through a radial passage provided in the camshaft 10, an annular groove, and a connection passage 71 provided in the cylinder head 70. The retard passage 13 is connected to the second connection port 91 b of the switching valve 90 through a radial passage and an annular groove provided in the camshaft 10 and a connection passage 72 provided in the cylinder head 70.
[0011]
In this embodiment, the switching valve 90 includes a cylindrical housing 91 that is liquid-tightly fitted in a mounting hole 74 provided in the cylinder head 70, and a spool that is fitted into the housing 91 so as to be movable in the axial direction. 92, a spring 93 that urges the spool 92 in the axial direction, a movable core 94 that has a shaft portion that is always in contact with the spool 92 that is urged by the spring 93, and an outer periphery of the movable core 94. A coil 95 wound around a cylindrical resin bobbin disposed, a yoke disposed between opposing surfaces of the bobbin and the housing 91, and a coupling between the two, and a movable core 94 in the bobbin inner hole adjacent to the movable core 94 The movable core 94 and the spool 92 are connected to the spring 93 by energizing the coil 95. The fixed core is disposed on the outer periphery of the bobbin. Anti to those that can be moved to the left in FIG. 1.
[0012]
The housing 91 is formed with first and second connection ports 91a and 91b made of annular grooves communicating with the connection passages 71 and 72, respectively. Each of the connection ports 91a and 91b has a plurality of radial directions formed in the housing 91. The passage communicates with the inner circumferential groove. Further, the housing 91 is provided with an annular groove connected to the hydraulic oil supply passage 100 from an oil pump (not shown) driven by the internal combustion engine between the first and second connection ports 91a and 91b. A port 91 c is formed, and the supply port 91 c is always in communication with an annular groove 92 d formed on the outer peripheral surface of the spool 92 through a plurality of radial passages formed in the housing 91. The annular groove 92d is axially communicated selectively with each inner circumferential annular groove of the housing communicated with the first and second connection ports 91a and 91b in accordance with the axial movement of the spool 92. It extends to. The spool 92 has an inner hole functioning as a discharge port 92c of the switching valve 90 by opening one end of a mounting hole 74 communicating with the cylinder head 70 through a discharge passage 73 provided in the cylinder head 70. It has radial passages 92b and 92c that extend in a radial direction from the inner hole and communicate with an annular groove formed on the outer peripheral surface. The radial passages 92b and 92c can communicate with the inner peripheral annular grooves of the housing communicated with the second and first connection ports 91b and 91a, respectively, in accordance with the axial movement of the spool 92. .
[0013]
In the switching valve 90 configured as described above, when the coil 95 is not energized, the supply port 91c is communicated with the second connection port 91b via the annular groove 92d, and the first connection port 91a is communicated with the radial passage 92a. When the coil 95 is energized, the supply port 91c communicates with the first connection port 91a through the annular groove 92d, and the second connection port 91b communicates with the discharge port 92c through the radial passage 92b. Communicated with Therefore, hydraulic oil is supplied to the retard passage 13 when the coil 95 is not energized, and hydraulic oil is supplied to the advance passage 12 when the coil 95 is energized.
[0014]
Thus, in this embodiment, the inner hole of the spool 92 constituting the discharge port 92c has a stepped shape, and a check ball 96, a spring A one-way valve consisting of 97 and a retainer 98 is provided. The check ball 96 always abuts against the step portion of the inner hole of the spool 92 by a spring 97 having a small spring force that is locked to one end of a retainer 98 that is fitted and fixed to the open end of the inner hole large diameter portion of the spool 92. Is biased to the side. Accordingly, the flow of hydraulic oil from the mounting hole 74 into the discharge port 92c is prevented, and the flow of hydraulic oil from the discharge port 92c to the mounting hole 74 (flow of low-pressure hydraulic oil that overcomes the small spring force of the spring 97). Only) is allowed.
[0015]
The inner rotor 20 is integrally fixed to the camshaft 10 by a single mounting bolt 81, and has vane grooves 21 for mounting the five vanes 60 so as to be movable in the radial direction. A passage for supplying and discharging hydraulic oil from the advance passage 12 to the advance oil chamber R1 defined by 60 (an annular groove communicating with the advance passage 12 and five communication holes extending radially outward from the annular groove) 24) and a passage 25 for supplying and discharging hydraulic oil from the retard passage 13 to the retard oil chamber R2 defined by each vane 60. Each vane 60 is urged radially outward by a vane spring 61 (see FIG. 1) accommodated in the bottom of the vane groove 21.
[0016]
The outer rotor 30 is assembled to the outer periphery of the inner rotor 20 so as to be relatively rotatable within a predetermined range. A front plate 40 and a rear plate 50 are joined to both sides of the outer rotor 30 and are integrally connected by three connecting bolts 82. Has been. In addition, five protrusions 31 are formed on the inner periphery of the outer rotor 30 at predetermined intervals in the radial direction, and the inner peripheral surface of these protrusions 31 is the inner rotor 20. The outer rotor 30 is rotatably supported by the inner rotor 20 so as to be in sliding contact with the outer peripheral surface.
[0017]
Each vane 60 has a circular arc cross-sectional shape at the tip, is attached to the vane groove 21 of the inner rotor 20 between the plates 40 and 50 so as to be movable in the radial direction, and each protrusion 31 of the outer rotor 30. The hydraulic pressure chamber R0 formed between the inner rotor 20 and the inner rotor 20 is divided into an advance oil chamber R1 and a retard oil chamber R2, and the circumferential end surfaces of the protrusions 31 formed on the outer rotor 30 , The phase (relative rotation amount) adjusted by the valve opening / closing timing control device is limited.
[0018]
In the valve timing control apparatus of the present embodiment configured as described above, the switching valve 90 appropriately controls the supply and discharge of hydraulic oil to and from the advance oil chamber R1 and the retard oil chamber R2. 2, that is, the most retarded state (the state in which each vane 60 is in contact with the rotational direction end surface of each projection 31 of the external rotor 30) to the most advanced angle (each projection 31 of the external rotor 30). The relative rotation amount (phase) between the inner rotor 20 and the outer rotor 30 is controlled until the vanes 60 are in contact with the end surface on the opposite side in the rotation direction.
[0019]
Here, in the most retarded state shown in FIG. 2, the switching valve 90 is in the state of FIG. 1, and the supply port 91c is communicated with the second connection port 91b via the annular groove 92d. Hydraulic oil from an oil pump (not shown) is supplied to the retarding oil chamber R2 through the passages 13 and 23 and 25. Accordingly, the side surface of each vane 60 on the advance oil chamber R1 side is the end surface on the rotation direction side of the protrusion 31 of the external rotor 30 by the hydraulic pressure of the hydraulic oil acting on the area of each vane 60 on the retard oil chamber R2 side. And the desired most retarded phase is maintained. In the present embodiment, in this most retarded state, a sealed space is formed by the one-way valve from the advance oil chamber R1 to the discharge port 92c through the passage 24, the advance passage 12 and the connection passage 71.
[0020]
In this state, the fluctuating torque applied to the camshaft 10 reduces the volume of the retarding oil chamber R2 against the hydraulic oil pressure (positive oil pressure) acting on the retarding oil chamber R2, and advances the oil. This acts to move the vane 60 to the side where the volume of the chamber R1 is increased. This torque is maintained from the retarding oil chamber R2 by the reaction force of the positive hydraulic pressure, and the above-mentioned sealing is performed by the action of the one-way valve. Since negative pressure is generated in the space, the advance oil chamber R1 is held by a reaction force due to negative hydraulic pressure. Therefore, according to the present embodiment, the torque applied to the camshaft 10 in the most retarded state is hydraulically maintained on both side surfaces of each vane 60, so that the maximum pressure receiving area of the vane is about ½ that of the conventional device. A desired phase in the retarded state can be stably maintained.
[0021]
Similarly, in the most advanced state, the coil 95 of the switching valve 90 is energized, and the supply port 91c is communicated with the first connection port 91a via the annular groove 92d. The hydraulic oil from an oil pump (not shown) is supplied to the advance oil chamber R1 through the passage 24, and from the retard oil chamber R2 through the passage 25, the retard passage 13 and the connection passage 72 by a one-way valve. A sealed space reaching the discharge port 92c is formed. As a result, similarly to the most retarded state described above, the varying torque applied to the camshaft 10 is hydraulically held on both side surfaces of each vane 60, and the desired phase in the most advanced angle state is stably maintained.
[0022]
It should be noted that the balance state in the intermediate phase, which is the state between the most retarded angle state and the most advanced angle state (the pressing force by the advance hydraulic pressure in each advance angle oil chamber R1 is the delay in each retard angle oil chamber R2). In a state balanced with the sum of the pressure applied by the angular hydraulic pressure and the torque applied to the camshaft 10, the annular groove 92d of the spool 92 is slightly overlapped with the inner peripheral annular groove of the first connection port 91a in the axial direction. Energization of the coil 95 of the switching valve 90 is controlled so that the supply port 91c communicates with the first connection port 91a and the second connection port 91b does not communicate with either the annular groove 92d or the radial passage 92b. As a result, a sealed space is formed from the retarding oil chamber R2 to the second connection port 91b through the passage 25, the retarding passage 13, and the connection passage 72. Therefore, similarly to the above-described most retarded angle and most advanced angle states, even if a varying torque is applied to the camshaft 10, the varying torque is hydraulically held on both side surfaces of each vane 60, and a desired phase in the intermediate balance state. Is held stably.
[0023]
In the above embodiment, the present invention has been implemented in which the timing sprocket 51 is integrally provided on the outer periphery of the rear plate 50 and the rotational power is transmitted from the crankshaft via the crank sprocket and the timing chain. A timing pulley is integrally provided on the outer periphery of the external rotor 30 (which can be configured as a separate member and can be fixed integrally) so that rotational power is transmitted from the crankshaft via the crank pulley and the timing pulley. Can be similarly implemented. In the above embodiment, the present invention is applied to the valve opening / closing timing control device assembled to the intake camshaft 10, but the present invention is also applied to the valve opening / closing timing control device assembled to the exhaust camshaft. It can be implemented similarly.
[0024]
【The invention's effect】
As described above, according to the present invention, at the most retarded angle (or at the most advanced angle), hydraulic oil is supplied to the retarded oil chamber (or the advanced oil chamber), while the one-way valve is used. A sealed space is formed from the advance oil chamber (or the retard oil chamber) to the one-way valve via the discharge port of the switching valve. As a result, the volume of the retard oil chamber (advance oil chamber) is decreased and the volume of the advance oil chamber (retard oil chamber) is increased at the most retarded angle (or most advanced angle). When fluctuating torque is applied to the rotating shaft so as to move the phase conversion means to the side, the fluctuating torque is maintained by the reaction force from the retard oil chamber (advance oil chamber) by the positive hydraulic pressure, and advances. Since the corner oil chamber (retarding oil chamber) is held by the reaction force due to the negative hydraulic pressure, the desired pressure phase can be obtained without increasing the pressure receiving area of the phase conversion means or increasing the supplied hydraulic oil pressure. Can be held stably.
[Brief description of the drawings]
FIG. 1 is a longitudinal side view showing an embodiment of a valve timing control apparatus according to the present invention.
FIG. 2 is a cross-sectional view taken along line AA in FIG.
[Explanation of symbols]
10 Camshaft (Rotating shaft)
12 Advance angle passage (hydraulic oil supply / discharge means)
13 Delay passage (hydraulic oil supply / discharge means)
20 Internal rotor (rotating shaft)
30 External rotor (rotation transmission member)
31 Projection 40 Front plate 50 Rear plate 60 Vane (phase conversion means)
70 Cylinder head 73 Discharge passage 90 Switching valve (hydraulic oil supply / discharge means)
91 Housing 91a First connection port 91b Second connection port 91c Supply port 92 Spool 92c Discharge port 96 Check ball (one-way valve)
97 Spring (one-way valve)
R0 fluid pressure chamber (phase conversion means)
R1 Lead angle oil chamber (phase conversion means)
R2 retarding oil chamber (phase conversion means)

Claims (2)

A rotation transmission member mounted on a rotation shaft for opening and closing a valve so as to be relatively rotatable within a predetermined range, and movable between at least one of the rotation transmission member and the rotation shaft between the rotation transmission member and the rotation shaft A phase converting means provided on the rotation transmitting member, a fluid pressure chamber formed between the rotation transmitting member and the rotating shaft and divided into an advance oil chamber and a retard oil chamber by the phase converting means, and the advance At least first and second connection ports connected to the corner oil chamber and the retard oil chamber, a discharge port connected to the discharge passage, and a supply port connected to a hydraulic pressure supply source, A switching valve for selectively communicating the first and second connection ports with at least the supply port and the discharge port or the discharge port and the supply port in order to supply and discharge hydraulic oil to and from the oil chamber and the retarding oil chamber. Hydraulic oil supply / discharge means comprising In the valve opening / closing timing control device used for controlling the opening / closing timing of an intake valve or an exhaust valve of an internal combustion engine, the exhaust passage is connected between the discharge port and the discharge passage of the switching valve. A valve opening / closing timing control device comprising a one-way valve that allows only the flow of hydraulic oil to the valve. 2. The valve opening / closing timing control device according to claim 1, wherein the phase conversion means comprises a vane attached to one of the rotating shaft and the rotation transmitting member.

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