JP2551823Y2 - Valve timing control device for internal combustion engine - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve timing control apparatus for variably controlling the opening / closing operation timing of intake and exhaust valves of an internal combustion engine in accordance with an operation state.

[0002]

2. Description of the Related Art For example, as a conventional valve timing control device for an internal combustion engine for an automobile, there is known a device described in Japanese Patent Application Laid-Open No. 63-131808 filed by the present applicant.

[0003] This is because at least one of teeth provided on the inner and outer circumferences is provided between a timing pulley to which a driving force is transmitted from a crankshaft of an engine and a camshaft arranged coaxially with the timing pulley. A cylindrical gear which is a helical gear is arranged. The cylindrical gear has outer teeth provided on the outer periphery on the inner periphery of the timing pulley, and inner teeth provided on the inner periphery meshed with outer teeth on the outer periphery of the camshaft. The torque is transmitted to the camshaft. Also, a two-path hydraulic circuit for supplying and discharging hydraulic pressure to each of the first and second hydraulic chambers formed before and after the cylindrical gear is provided with a two-way solenoid valve provided upstream of each hydraulic circuit. By switching by the switching operation, the cylindrical gear is moved in the front-rear axis direction of the camshaft, and the relative rotation between the timing pulley and the camshaft is obtained, and the opening / closing timing of the intake / exhaust valve by the camshaft is adjusted according to the operating state of the engine. It controls the advance and delay.

[0004] By moving the cylindrical gear in the axial direction by a two-path hydraulic circuit as described above,
Excellent effects such as good movement responsiveness of the cylindrical gear can be ensured and an effective variable width of valve timing can be increased.

[0005]

However, in the above conventional valve timing control device, the first hydraulic chamber to which the hydraulic pressure is supplied / discharged from the hydraulic circuit is formed by the front end of the cylindrical gear and the front cover of the timing pulley. Therefore, the length of the entire device in the axial direction is inevitably increased, and the size of the device is inevitably increased. As a result, the weight of the device increases, and the degree of freedom in layout in the engine room is restricted.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems. In particular, a hydraulic chamber on the front side of the phase conversion means is formed by cutting out the peripheral surface of the phase conversion means. It is characterized by doing.

[0007]

According to the present invention, the front hydraulic chamber is not formed at the front end side of the phase conversion means, but is formed at the peripheral surface by notching.
No axial space is required for forming the front hydraulic chamber, and the axial length of the device can be reduced.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings.

FIGS. 1 to 3 show an embodiment in which the present invention is applied to an intake valve side. A sleeve 2 is fixed to one end 1a of a camshaft 1 for opening and closing the intake valve by a bolt 3 in the axial direction. At the same time, a timing sprocket 4 is supported on the outer periphery of the sleeve 2 as a rotating body to which rotational force is transmitted from a crankshaft. Also, sleeve 2
A phase converter 5 for converting the relative rotation phase between the camshaft 1 and the timing sprocket 4 is interposed between the timing sprocket 4 and the timing sprocket 4.

The sleeve 2 has a thick cylindrical sleeve main body 2a, a thin cylindrical small diameter section 2b provided at the front end of the sleeve main body 2a, and a camshaft one end 1 provided at the rear end.
a large-diameter flange portion 2c fitted with the small-diameter flange portion 1b of FIG.
It is composed of

As shown in FIGS. 2 and 3, the timing sprocket 4 has a gear 4b on which a timing chain is wound on the outer peripheral surface on the rear end side of the cylindrical main body 4a, and has substantially a gear 4b on the inner peripheral surface on the front end side. The trapezoidal projections 8 and 9 are arranged to face each other.

The phase conversion means 5 comprises an arm 12 which is fastened to the outer periphery of the small diameter portion 2b of the sleeve 2 together with the front cover 11 of the timing sprocket 4 by the bolt 3.
An annular piston 13 interposed between the sleeve 2 and the timing sprocket 4 so as to be able to advance and retreat in the axial direction of the camshaft, and four annular pistons 13 provided on the front surface of the piston 13 at equal intervals in the circumferential direction. Sliders 14, 15, 16, 1
7 is provided.

As shown in FIG. 2, the arm 12 has two end surfaces 1 on each of fan-shaped extending portions 18 and 19 extending from a fixed end.
8a, 18b, 19a and 19b are formed to be inclined in directions opposite to each other. Each of the sliders 14 to 17 has a substantially rectangular piece shape as shown in FIGS. 2 and 3, and is rotatably supported by the front end of the piston 13 via pins 20 penetrating in the inner axial direction. . In addition, one side surface 14a, 15a, 16a, 17a abutting on each side end surface 18a-19b of each extension part 18, 19 is formed on each side end surface 18a-1.
9b, while the other side surface 14b, 15b, 16b, 17b of each arc shape is formed with the projections 8, 9
Are in sliding contact with the concave side surfaces 8a, 8b, 9a, 9b.
Further, a pair of opposing sliders 14 and 16 are provided with coil springs 21 wound around the outer circumferences of the pins 20 and 20, respectively.
With the spring force of 22, one side surface 14a, 16a becomes the side end surface 18a,
The gap 19, that is, the backlash is prevented by always abutting the contact 19a.

An annular first hydraulic chamber 23 is formed between the rear end of the piston 13 and the large-diameter flange 2c as shown in FIG. A second hydraulic chamber 24 is formed on the peripheral surface. That is, in the second hydraulic chamber 24, the inner peripheral surface of the front end portion of the piston 13 is notched in an annular shape, and the notched peripheral surface is a pressure receiving surface. A compression spring 2 having a small spring force for urging the piston 13 and the sliders 14 to 17 in the advance direction (forward) when the engine is stopped is provided in the first hydraulic chamber 23.
5 are armed.

The piston 13 moves forward and backward by hydraulic pressure supplied and discharged from first and second hydraulic circuits 26 and 27 of two paths.

The first hydraulic circuit 26 is formed to penetrate the cylinder head and cam bearing 28 and the cam shaft 1 continuously in the radial direction, and has an upstream end at an oil main gallery 29.
Oil passage 31 connected to oil pump 30 through
And each bolt hole 1c, 2 of the camshaft 1 and the sleeve 2.
d, an annular passage 32 formed between the inner peripheral surface and the shaft outer peripheral surface of the bolt 3, and a radial passage formed in the vicinity of the large-diameter flange portion 2c of the sleeve 2 to form the annular passage 32 and the first hydraulic pressure. A radial passage 33 communicating with the chamber 23.

The second hydraulic circuit 27 is formed continuously with a second oil passage 34 formed in parallel with the first oil passage 31 and in an inner axial direction of an outer peripheral side of the camshaft 1 and the sleeve 2. , An axial passage 3 having one end communicating with the second oil passage 34
5 and a communication passage 36 formed in the front end face of the sleeve main body 2a along the radial direction and communicating the axial passage 35 with the second hydraulic chamber 24.

A connecting portion between the first and second oil passages 31 and 34 and the oil main gallery 29 is provided with one 4
A directional solenoid valve 37 is interposed. This solenoid valve 37
Connects the oil main gallery 29 to one of the first hydraulic circuit 26 and the second hydraulic circuit 27, and connects the other to the drain passage 3 connected to the end of the solenoid valve 37.
8 to control switching. The electromagnetic valve 37 is provided with a command from a control unit (not shown) for detecting an operating state of the engine based on information signals such as an engine speed and an intake air amount output from a crank angle sensor, an air flow meter, and the like (not shown). The switching operation described above is performed by the signal.

Therefore, according to this embodiment, for example, when the engine is under a low load, the control unit outputs an OFF signal to the four-way solenoid valve 37, and as shown in FIG. The hydraulic oil in the second hydraulic chamber 24 is quickly discharged through the communication passage 36, the axial passage 35, and the second oil passage 34 so that the hydraulic fluid communicates with the drain passage 38. At the same time, since the solenoid valve 37 allows the oil main gallery 29 to communicate with the first oil passage 31, the oil pump 30
The hydraulic oil pressure-fed from the annular passage 32 and the radial passage 3
3 is supplied to the first hydraulic chamber 23 through the first hydraulic chamber 2.
The internal pressure of 3 rises. Accordingly, the piston 13 quickly moves forward (position shown) by a combined force of the high oil pressure in the first hydraulic chamber 23 and the spring force of the compression spring 25. Therefore, one side 14 of each of the sliders 14 and 16
a, 16a are opposed end faces 18a, 19a of the arm 12
The arm 12 while pressing the
Is rotated in the direction opposite to the rotation direction of. As a result, the camshaft 1 relatively rotates in one direction with respect to the timing sprocket 4, and controls the closing timing of the intake valve to be delayed. Accordingly, combustion can be stabilized and fuel efficiency can be improved.

On the other hand, when the engine is under a high load, the solenoid valve 37
The N signal is output and the switching operation is performed. As shown in FIG.
The oil passage 31 and the drain passage 28 communicate with each other, whereby the hydraulic oil in the first hydraulic chamber 31 is discharged. At the same time, the solenoid valve 37 is connected to the oil main gallery 29 and the second oil passage 34.
To the second hydraulic chamber 24, the second oil passage 34,
Hydraulic oil is supplied through each of the axial passage 35 and the communication passage 36, and the internal pressure increases. Therefore, the piston 13
Moves quickly backward (position shown) while compressing the compression spring 25 with high oil pressure in the second hydraulic chamber 24. Accordingly, the side surfaces 15a, 17a of the different sliders 15, 17 press different end surfaces 18b, 19b of the arm 12 this time to rotate the arm 12 in the rotation direction of the timing sprocket 4. As a result, the camshaft 1 relatively rotates in the other direction with respect to the timing sprocket 4, and controls the closing timing of the intake valve to be advanced. Accordingly, the intake charging efficiency is increased, and the output can be improved.

As described above, in this embodiment, the piston 13 and the sliders 14 to 17 are moved forward and backward by the hydraulic pressure supplied and discharged relatively to the two hydraulic chambers 23 and 24. The movement responsiveness is sufficiently improved as compared with the case where a spring force is used. Further, by finely controlling the hydraulic pressure, the piston 13 and the like can be stopped at an arbitrary position, thereby enabling stepless control of the valve timing.

Further, since the switching of each hydraulic circuit is performed by one four-way solenoid valve 37, the hydraulic circuit can be simplified, the number of parts can be reduced, the efficiency of manufacturing work can be improved, and the manufacturing cost can be reduced. Cost reduction can be achieved.

Further, since the second hydraulic chamber 24 is formed not on the front end side of the piston 13 but on the inner peripheral surface, no axial space for forming the second hydraulic chamber 24 is required, and the axial length of the device is reduced. Can be shortened.

The present invention is not limited to the configuration of the above-described embodiment, but can be applied to, for example, a configuration in which the phase conversion means is formed of a cylindrical gear or a clutch mechanism.

[0025]

As is apparent from the above description, according to the valve timing control apparatus for an internal combustion engine according to the present invention, the phase conversion means is moved forward and backward by the hydraulic pressure from the two-path hydraulic circuit. The front hydraulic chamber is notched in the peripheral surface of the phase conversion means as well as the movement responsiveness is improved, so that the axial length of the device can be shortened as much as possible. As a result, the weight and size of the device can be reduced,
The degree of freedom in layout in the engine room is improved.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram showing an embodiment of the present invention.

FIG. 2 is a view taken in the direction of arrow A in FIG. 1;

FIG. 3 is a sectional view taken along line BB of FIG. 2;

FIG. 4 is an overall configuration diagram showing the operation of the present embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Cam shaft, 4 ... Timing sprocket (rotating body), 5 ... Phase conversion means, 23,24 ... First and second hydraulic chambers, 26,27 ... First and second hydraulic circuits.

Claims (1)

(57) [Scope of request for utility model registration] 1. A phase conversion means interposed between a rotating body driven by an engine and a camshaft so as to be able to move forward and backward to convert a relative rotation phase between the two, and before and after the phase conversion means. A hydraulic circuit for supplying and discharging hydraulic pressure to and from each of the hydraulic chambers, and a two-path hydraulic circuit for moving the phase conversion means forward and backward, wherein the front hydraulic chamber is provided on the peripheral surface of the phase conversion means. A valve timing control device for an internal combustion engine, wherein a notch is formed.