JP3528385B2 - Valve timing control device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve opening / closing timing control device capable of changing the opening / closing operation timing of intake and exhaust valves in an internal combustion engine, and more particularly to a main component thereof. The present invention relates to a valve opening / closing timing control device in which a mechanism is configured in a cylinder head to improve the size of an internal combustion engine. 2. Description of the Related Art In an internal combustion engine, the opening and closing operation timings of intake and exhaust valves are determined by a valve operating mechanism using a camshaft according to the characteristics and use of the engine. It is difficult to provide an optimal valve opening / closing operation timing in the entire rotation range. Therefore, a valve opening / closing timing control device capable of changing the valve opening / closing operation timing according to the rotation state of the internal combustion engine is provided as an auxiliary mechanism of the valve operating mechanism. One type of valve opening / closing timing control system changes the relative phase between a timing pulley and a camshaft. As a conventional configuration according to this method, in an internal combustion engine that transmits engine rotation power from a crankshaft to a camshaft by a power transmission means such as a timing belt or a timing chain, a plurality of vanes extending in a radial direction are set on a camshaft side. While fixing the attached rotor, each hydraulic chamber is formed in the inner peripheral portion of the timing pulley coaxially fitted to the rotor, and the vanes are engaged with the respective hydraulic chambers as partition members. A vane type valve opening / closing timing control device is disclosed in, for example, Japanese Patent Application Laid-Open No. 1-92504. In this valve timing control apparatus, the advance hydraulic pressure and the retard hydraulic pressure according to the operating state of the internal combustion engine act on the first hydraulic chamber and the second hydraulic chamber, respectively, defined in the hydraulic chamber by the vanes. Thus, the valve opening / closing timing control is performed by changing the relative phase between the camshaft and the timing pulley. [0004] When the valve timing control device is disposed outside the cylinder head as described above, the leakage of hydraulic oil from the hydraulic chamber to the outside is restricted by the hydraulic oil. In addition to inviting a decrease in the volume, it is necessary to set the tightness of the hydraulic chamber strictly in order to contaminate the peripheral equipment, so a sealing member is required, but it is housed in the cylinder head,
When trying to reduce the size of the internal combustion engine, the leakage of hydraulic oil from the hydraulic chamber to the outside is collected in the cylinder head, so there is no need to set the tightness of the hydraulic chamber tightly. And a simple configuration can be achieved. [0005] However, in this case, for example, when the internal combustion engine is stopped for a long time, the operating oil in the hydraulic chamber is reduced, and there is a possibility that the vane may make a noise at the time of restart. SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and has a valve opening / closing timing control device capable of simplifying a structure without generating a tapping sound due to a vane when the internal combustion engine is restarted after a long stop. Is to provide this. [0007] The technical means of the present invention taken to solve the above-mentioned problem is that the valve opening / closing timing control device is rotatably supported by a cylinder head, and is provided with an internal combustion engine. The first camshaft to which the rotational power from the crank pulley is transmitted via the timing pulley and the rotational power of the first camshaft via a power transmission means capable of phase shifting with respect to the first camshaft. A phase is varied between the transmitted second camshaft and the second camshaft in accordance with an operation state to change a relative opening / closing timing of each valve of the first camshaft and each valve of the second camshaft. A valve opening / closing timing control device, comprising: a plurality of radially extending vanes, integrated with one of the first camshaft or the second camshaft extending into a cylinder head. Opening and closing comprising a housing member in which a plurality of pressure chambers are formed in a circle so that the rotor and the power transmission means are integrated with the rotor and each of the vanes is fitted between the rotor and the rotor. A timing control mechanism; a first pressure chamber in which the pressure chamber is defined by each of the vanes;
Means for causing hydraulic oil to act on the pressure chamber from the cylindrical portion so that the pressure chamber functions as an advance chamber and a retard chamber, and a part of the valve opening / closing timing control mechanism is always operated. The configuration is such that a working fluid reservoir is provided in a cylinder head so as to be immersed in oil. According to the above means, when the first camshaft is driven by the timing pulley rotating in synchronization with the crank pulley, the rotation of the first camshaft is transmitted to the second camshaft via the power transmission means. To drive the valve group in each camshaft. At that time, the valve opening / closing timing control device uses the action of the hydraulic oil to the pressure chamber,
The phase of the second camshaft is varied with respect to the power transmission means, and the relative phase between the first camshaft and the second camshaft is changed. When the internal combustion engine is stopped for a long time, the hydraulic oil in the pressure chamber leaks to the outside while the internal combustion engine is stopped, but the leaked hydraulic oil accumulates in the hydraulic oil reservoir provided in the cylinder head, and Since part of the valve opening / closing timing control mechanism is always immersed, all the hydraulic oil in the pressure chamber does not leak outside. Therefore, at the time of restart, generation of the vane tapping sound is prevented by the hydraulic oil remaining in the pressure chamber. An embodiment of a valve timing control apparatus according to the present invention will be described below with reference to the drawings. In FIG. 1, a valve timing control apparatus according to the present embodiment is applied to a DOHC type internal combustion engine, and includes an exhaust valve camshaft 2 (first valve) rotatably supported by a cylinder head 1. The camshaft 3 for the exhaust valve and the camshaft 3 for the intake valve (the second camshaft)
A gear 4 mounted on the outer circumference of the camshaft 3 for relative rotation and a gear 5 mounted on the outer circumference of the camshaft 3 for the intake valve so as not to rotate relatively.
Are connected via a power transmission means 6 formed by meshing. The valve timing control mechanism described below is mounted on the exhaust valve camshaft 2 here. The timing pulley 7 is mounted on the cylinder head 1
It is fastened to the camshaft 2 by a bolt 8 fastened to an end of the exhaust valve camshaft 2 (hereinafter simply referred to as the camshaft 2) projecting from the inside. At an eccentric position of the bolt 8, a stopper pin 9 which performs a rotation preventing function is provided. The cylindrical portion 10 of the camshaft 2 extending into the cylinder head 1 is formed by a male screw portion 11 from the front side and a portion in which circumferential oil passages 12 and 13 for advancing and retarding are formed. A journal portion 14 is formed on the rear side of the portion where the circumferential oil passages 12 and 13 are formed, and the journal portion 14 continues to the cam forming portion 15.
The gear 4 is mounted on the outer periphery of the journal section 14 so as to be relatively rotatable as described above. Thus, a valve opening / closing timing control mechanism 16 which is a main component of the valve opening / closing timing control device is mounted on the portion where the circumferential oil passages 12 and 13 are formed. Valve timing control mechanism 16
As shown in FIG. 3, the rotor 17 has an inner periphery, a radially extending vane 18 having one end anchored in a groove formed in the rotor 17, and a concave groove 19a formed in an inner periphery in a circle. The annular housing member 19 in which the rotor 17 is coaxially enclosed and the convex surface between the concave grooves 19a is in sliding contact with the outer peripheral surface of the rotor 17
As shown in FIG. 1, the rotor 17, the vane 18, and the annular housing member 19 are sandwiched in the axial direction.
9a is a pressure chamber 20 fitted with a vane 18 as a piston.
The front housing member 21 and the rear housing member 22 are pressed against each other by a bolt 23 screwed into the gear 4. The front plate housing member 21 and the annular housing member 1
9 between the front side surface and the rear plate housing member 22 and the rear side surface of the annular housing member 19 are sealed by metal touch. Further, the valve opening / closing timing control mechanism 16 has a side face facing the rear side of the rotor 17 abutting on the journal portion 14, and in this abutting state, the male screw portion 11 faces the side face facing the front side of the rotor 17. Nut 2 fastened to
5 and the journal 14. Thereby, the rotor 17 is rotated integrally with the camshaft 2. In the valve opening / closing timing control mechanism 16, a pin 32 radially driven into the cylindrical portion 10 engages with a positioning groove 33 formed in the inner peripheral portion of the rotor 17, thereby performing circumferential positioning. ing. The valve opening / closing timing control mechanism 16
As shown in FIGS. 1 to 3, the hydraulic fluid is housed in a hydraulic fluid reservoir 1 a, which is a concave portion formed on the cylinder head 1, and a part of the fluid is constantly immersed in the hydraulic fluid 50. Hydraulic oil for lubricating the journals of the camshafts 2 and 3 can flow into the hydraulic oil reservoir 1a. In the present embodiment, the oil level of the hydraulic oil 50 stored in the hydraulic oil reservoir 1 a is set near the lowermost end of the rotor 17. An operating oil pressure is supplied to the pressure chamber 20 from an oil pressure supply device 36. The hydraulic supply device 36 includes a hydraulic control valve 37 for controlling the valve opening / closing timing control mechanism 16 and a control device 39.
The oil passage 27 formed in the camshaft 2 at the axis of the shaft is connected to the A port of the hydraulic control valve 37 through a circumferential groove 42 formed in the cylinder head 1. The oil passage 26 formed in the camshaft 2 in parallel with the oil passage 27 in an axially symmetric manner is connected to the B port of the hydraulic control valve 37 through a circumferential groove 41 formed on the camshaft 2. A hydraulic pump 38 driven by, for example, an internal combustion engine is connected to the P port of the hydraulic control valve 37, and a reservoir 42 is connected to the R port, and the operation of the hydraulic control valve 37 is controlled by the control device 39. As a result, the valve opening / closing timing control mechanism 16 performs the advance and retard operations and maintains the neutral position, as described later. The oil passage 26 communicates with each of the oil passages 29 radially formed on the rotor 17 via the circumferential oil passage 12, and the oil passage 27 communicates with each of the radially formed rotors 17 via the circumferential oil passage 13. It communicates with the oil passage 28. Each oil passage 29 is provided in the first hydraulic chamber 30 of each pressure chamber 20 defined by the vane 18.
Of the second hydraulic chamber 31, the hydraulic oil is guided to the first hydraulic chamber 30, and each oil passage 28 guides the hydraulic pressure to the second hydraulic chamber 31. Here, the oil passage 27 formed in the axial direction is
The other passages are shut off by balls 34 and 35 pressed into both ends. In the above configuration, when the camshaft 2 is driven by the timing pulley 7 to which the rotational power of the crank pulley is transmitted, the rotation of the camshaft 2 causes the rotor 7, the vane 18, the annular housing member 19 and the bolt 23 to rotate. The gears are transmitted to the gear 4 via the gear 4 and further transmitted to the camshaft 3 via the gears 4 and 5, so that the valves of the camshaft 2 and the valves of the camshaft 3 are driven. Here, the phase of the gear 4 can be shifted in the circumferential direction with respect to the journal portion 14 of the camshaft 2.
When the operating oil pressure from the hydraulic pump 38 acts on the second hydraulic chamber 31 via the hydraulic control valve 37 of the hydraulic supply device 36 (the first hydraulic chamber 30 is communicated with the reservoir), the gear 4 is moved together with the annular housing member 19. The rotor 17 and the camshaft 2 are rotated clockwise in FIG. 3 to advance the relative phase of the camshaft 3 with respect to the camshaft 2 by the maximum phase angle θ of the vane 18. When the operating oil pressure from the hydraulic pump 38 acts on the first hydraulic chamber 30 (the second hydraulic chamber 31 is communicated with the reservoir), the gear 4 together with the annular housing member 19 moves the rotor 17 and the camshaft 2 together. At the above-described maximum advance position, the camshaft 3 rotates counterclockwise in FIG. 3 and the camshaft 3 with respect to the camshaft 2 by the maximum phase angle θ of the vane 18 from the above-described maximum advance position.
Delay the relative phase of This makes it possible to adjust the opening / closing timing of each valve on the camshaft 3 and the opening / closing timing of each valve on the camshaft 2 at the time of advance and retard. In this embodiment, the valve timing control mechanism 16
In addition to the above, the only member that consumes the axial dimension is the nut 25, and the valve opening / closing timing control mechanism 16 is housed in the cylinder head 1 without increasing the size of the internal combustion engine main body. It does not protrude as an external device outside the main body, and the appearance of the internal combustion engine can be simplified and miniaturized. For example, the empty space in the engine room of the car increases, the degree of freedom of arrangement of other parts, or the arrangement of new parts The property becomes good. In this embodiment, the cylinder head 1
A concave hydraulic oil reservoir 1a is formed on the upper side, and a valve opening / closing timing control mechanism 16 is housed in the hydraulic reservoir 1a. As a result, the hydraulic oil 50 in the hydraulic oil reservoir 1a
As described above, a part of the valve timing control mechanism 16 is always immersed. During the operation of the internal combustion engine, the hydraulic oil in the hydraulic oil reservoir 1a is agitated as the valve opening / closing timing control mechanism 16 rotates, and is used for lubrication of the gears 4 and 5, so that the hydraulic oil level fluctuates. I do. When the internal combustion engine is stopped, the stirred working oil stays in the working oil reservoir 1a. When the internal combustion engine is stopped for a long time, the front plate housing member 21 sealed with a metal touch is used.
And the front side of the annular housing member 19 and between the rear plate housing member 22 and the annular housing member 19.
Hydraulic chamber 30 and second hydraulic chamber 31 from between the rear side surfaces of
Hydraulic oil leaks from the inside, but the leaked hydraulic oil accumulates in the hydraulic oil reservoir 1a, and the hydraulic oil remains in the hydraulic chamber located in the hydraulic oil. Therefore, even if the internal combustion engine is restarted in this state, the working oil remaining in the hydraulic chamber suppresses the vane 18 from abutting against the circumferential end surface of the hydraulic chamber, and the hitting caused by the abutment is suppressed. Is prevented.
The working oil reservoir may be formed as a recess along the outer shape of the valve opening / closing timing control mechanism 16 as shown by a dashed line 1b in FIG. As described above, according to the present invention, even if the hydraulic oil in the pressure chamber leaks to the outside while the internal combustion engine is stopped for a long time, the leaked hydraulic oil is provided on the cylinder head. A portion of the valve opening / closing timing control mechanism is constantly immersed in the accumulated hydraulic oil and the accumulated hydraulic oil. Therefore, all the hydraulic oil in the pressure chamber does not leak to the outside, so that the operating oil remaining in the pressure chamber at the time of restart prevents generation of the sound of the vane. Therefore, it is possible to simplify the configuration without requiring a sealing member without requiring a strict sealing property for the pressure chamber.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view showing an embodiment of a valve timing control apparatus according to the present invention. FIG. 2 is a side view showing the valve timing control apparatus according to the embodiment. FIG. 3 is a sectional view taken along line AA of FIG. 3; [Description of Signs] 1 Cylinder head 1a Hydraulic oil reservoir 2 First camshaft 3 Second camshaft 6 Power transmission means 7 Timing pulley 10 Cylindrical section 16 Valve opening / closing timing control mechanism 18 Vane 19, 21, 22 Housing member 20 pressure chamber

Claims (1)

(57) [Claims] [Claim 1] Rotatably supported by a cylinder head,
A first camshaft to which rotational power from a crank pulley of the internal combustion engine is transmitted via a timing pulley; and a power transmission in which the rotational power of the first camshaft can be phase-shifted to the first camshaft. The phase of the first camshaft is varied between the second camshaft and the second camshaft transmitted through the second camshaft. A valve opening / closing timing control device for changing an opening / closing timing, comprising: a plurality of radially extending vanes;
And the rotor integrated with one of the camshaft and the second camshaft and the power transmission means so as to include the rotor and fit the respective vanes between the rotor and the rotor. A valve opening / closing timing control mechanism including a housing member in which a plurality of pressure chambers are formed in a circle, and a first pressure chamber and a second pressure chamber in which the pressure chambers are defined by the vanes; Means for causing hydraulic oil to act on the pressure chamber from the cylindrical portion so as to function as a square chamber, and operating the valve opening / closing timing control mechanism on the cylinder head so that a part thereof is always immersed in the hydraulic oil. A valve timing control device comprising an oil reservoir.