JPH09222004A - Valve timing control device for internal combustion engine - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To improve efficiency of manufacturing work and assembling work while preventing deterioration of strength and rigidity of a cylinder head, a cam shaft, and the like. A cylindrical gear 14 meshed between a cylindrical main body 1a of a sprocket 1 and a sleeve 3 of a camshaft 2.
Is moved in the camshaft axial direction by the relative pressure of the hydraulic pressure of the hydraulic circuit 19 and the spring force of the compression spring 20 to convert the relative rotational phase of the both 1 and 2, thereby opening / closing the intake valve. Make it variable. The supply passage 24, the valve hole 25, the supply / discharge passage 27, and the drain passage 28 of the hydraulic circuit 19 are formed in an oil passage forming body 32 independent of the sprocket 1 and the camshaft 2, and the oil passage forming body is formed. The front end of the sprocket 1 is rotatably supported by the upper end 32 b of 32.

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 device for varying the opening / closing timing of intake / exhaust valves of an internal combustion engine for an automobile, for example, according to the engine operating condition.

[0002]

2. Description of the Related Art Various valve timing control devices of this kind have been conventionally provided, and generally, a cylindrical sprocket to which a rotational force is transmitted from a crankshaft of an engine through a timing chain, and an outer periphery. The cam shaft, which has a cam at its one end and is fixed to one end, is engaged with the cam shaft, which is inserted through the tubular body of the sprocket, and the front and rear tubular bodies and the sleeve, via helical teeth on the inner and outer circumferences. While having a tubular gear that can move back and forth.

The cylindrical gear is moved in the front-rear direction by the relative pressure between the hydraulic pressure supplied to and discharged from the pressure chamber on the front end side via a hydraulic circuit according to the engine operating state and the spring force of the compression spring on the rear end side. By moving to, the relative rotational phase of the front and rear sprockets and the cam shaft is converted, and thereby, for example, the opening / closing timing of the intake valve is controlled to be advanced or delayed.

[0004]

However, in the above-mentioned conventional valve timing control device, the supply oil passage and the discharge oil passage of the hydraulic circuit for supplying and discharging the hydraulic pressure to and from the pressure chamber are the cylinder head and the cam. Since it is formed inside the shaft, etc., by punching holes inside the cylinder head, the cam shaft, etc., their strength and rigidity are reduced,
The supporting rigidity of each part also decreases. As a result, engine vibration and vibration noise may increase.

Therefore, as in the invention described in Japanese Patent Laid-Open No. 4-228813, for example, a supply oil passage and a discharge oil passage of a hydraulic circuit are provided in a housing provided at a front end portion of a timing pulley which is a rotating body. Although there is also one provided with, a pressure chamber is formed on the front end side of this housing, a piston is arranged inside the housing so as to be slidable in the front-rear direction, and the end portion of the camshaft is rotatable. To support. That is, the housing is not provided separately from the piston, the camshaft, etc., but is provided in a close relationship in terms of the configuration, so that the housing and each component are assembled with high precision and processing accuracy. Is required, resulting in a decrease in manufacturing work and assembly work efficiency.

[0006]

SUMMARY OF THE INVENTION The present invention has been devised in view of the above-mentioned problems of the prior art. The invention of claim 1 is directed to a cam driven by a rotational force transmitted from an engine through a rotating body. A camshaft for opening and closing the intake and exhaust valves via the rotary shaft and the camshaft, which is interposed between the rotary body and the camshaft and is operated by the hydraulic pressure supplied from the hydraulic circuit of the drive mechanism. In a valve timing control device including a movable body that converts the relative rotational phase of the oil passage, the oil passage forming body having the oil passage of the hydraulic circuit formed therein is formed separately from the rotating body and the camshaft. At the same time, one end of the oil passage structure is slidably inserted into the front end of the rotary body, and the front end of the rotary body is rotatably supported.

According to the present invention, since the oil passage structure is provided separately from the rotating body and the cam shaft, it is not necessary to make a hole in the cylinder head, the cam shaft, etc., so that the overall rigidity and supporting rigidity are reduced. Is suppressed, and in particular, since one end is simply inserted through the front end of the rotating body and does not hold the hydraulic chamber, piston, etc. as in the conventional case, It is not closely related and does not require high assembly or processing accuracy. Further, since the oil passage structure body rotatably supports the front end portion of the rotating body, a stable posture can be secured without the rotating body and the cam shaft falling down due to the tension of the timing belt or the like.

According to a second aspect of the present invention, the movable body is operated by a relative pressure between the hydraulic pressure of the hydraulic circuit and the spring force of the spring member.

The invention of claim 3 is characterized in that the movable body is operated by relative hydraulic pressure acting from the hydraulic circuit to the front and rear of the movable body.

The invention of claim 4 is characterized in that the movable body is operated by ON / OFF two-stage switching control via a hydraulic circuit.

According to a fifth aspect of the present invention, the movable body is controlled to operate in multiple stages via a proportional solenoid type electromagnetic actuator provided in a hydraulic circuit.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a first embodiment of the present invention, in which a sprocket 1 as a rotating body to which a rotational force is transmitted from a crankshaft of an engine through a timing chain, and a sleeve 3 from an axial direction of one end. Is fixed with bolts 4,
Cam shaft 2 having a cam for opening and closing the intake valve on the outer circumference
A movable body 5 interposed between the cylindrical main body 1a of the sprocket 1 and the sleeve 3 of the camshaft 2, and the movable body 5
And a drive mechanism 6 for moving the engine in the camshaft axial direction according to the engine operating state.

In the sprocket 1, a gear portion 1b around which a timing chain is wound is fixed to a bolt 7 at an end of the cylindrical body 1a on the camshaft side, and a front cover 8 is fixed to the front end by caulking. . As shown in FIGS. 4 to 6, the cylindrical main body 1a is formed with helical tooth-shaped inner teeth 9 on the inner periphery at the front end side, and the gear portion 1b is also provided.
The bent inner peripheral portion of the central side is slidably supported on the outer periphery of the camshaft 2. Further, the front cover 8 has an annular shape, and a support hole 8a is formed in the center.

As shown in FIG. 1, one end of the cam shaft 2 on the sleeve side is supported by a cam bearing 11 provided at the upper end of the cylinder head 10b on the cylinder block 10a. The sleeve 3 has a substantially cylindrical shape, and a bolt insertion hole 3 is formed in an inner axial direction of a partition wall provided at the center.
a is formed through, and the cylindrical fixed end is fitted to one end of the camshaft body, while the fitting groove 3b into which the head of the bolt 4 is fitted is formed in the cylindrical tip end. In addition to being formed, outer teeth 13 in the shape of a helical tooth are formed on the outer periphery of the cylindrical tip portion. Also, the fitting groove 3b
The sprocket 1 and the camshaft 2 are urged in a direction in which they are separated from each other between the bottom surface of the sprocket and the cylindrical inner peripheral portion of the front cover 8 to suppress the generation of hammering sound with the camshaft 2 due to the thrust force on the sprocket 1. Coil spring 1
2 are armed.

The movable body 5 includes a sleeve 3 and a tubular body 1.
a cylindrical gear 14 and a piston 15 interposed therebetween, and the cylindrical gear 14 has a front gear component and a rear gear component divided into two parts from a direction perpendicular to the axis. Are formed with helical inner and outer teeth 14a and 14b meshing with the front end inner teeth 9 and the outer teeth 13. In addition, the two gear components are elastically connected in a direction approaching each other by a pin 16 and a sprocket in order to absorb a backlash gap between the teeth 9, 13, 14a, and 14b. The piston 15 has a tubular shape and is connected to the rear gear component via a support pin 17 which is press-fitted into a predetermined portion in the circumferential direction.

The drive mechanism 6 includes a pressure chamber 1 formed at the front end side of the piston 15 as shown in FIGS. 1 and 4 to 6.
1, a hydraulic circuit 19 for moving the cylindrical gear 14 in the right direction (rear end side) in FIG. 1 and a cylindrical gear 14 elastically mounted on the rear end side of the piston 15 are shown in FIG. A compression spring 20 having a relatively large spring force, which is a spring member that is moved to the left, is provided.

The hydraulic circuit 19 has a main passage 23 through which hydraulic oil in an oil pan 21 is pumped through an oil pump 22, one end communicates with the main passage 23, and the other end leads to a valve hole 25. The supply passage 24 that communicates with the valve hole 2 at one end.
5, the other end is provided at one end of the valve hole 25 and a supply / discharge passage 27 that communicates with the pressure chamber 18 via the fitting groove 3b and a passage groove 26 formed in the inner peripheral surface of the front cover 8. Drain passage 28, a spool valve 30 slidably provided in a tubular valve body 29 fixed in the valve hole 25 to switch the flow path, and a proportional solenoid type valve for operating the spool valve 30. And an electromagnetic actuator 31.

The downstream end 24 of the supply passage 24
a, the valve hole 25, and the supply / discharge passage 27 are formed in the oil passage structure 32. That is, the oil passage structure 32 is formed independently of the sprocket 1 and the camshaft 2, and the lower end portion 32a is fixed to the side portion of the cylinder block 10a by the fixing bolt 33 and the lower end portion 32a. A downstream end 24a of the supply passage is formed therein. Also, a cylindrical upper end 32b is inserted through the support hole 8a of the front cover 8 through a wear-resistant seal ring 34, whereby the upper end 32b rotates the front cover 8, that is, the front end of the sprocket 1. It is supported freely. A supply / discharge passage 27 is formed in the upper end 32b. Further, the bulged portion 32 at the substantial center
The valve hole 25 is formed in c, and the drain passage 28 is formed in the rear end wall of the valve hole 25 of the bulging portion 32c.

The spool valve 30 has a valve body 29.
The supply hole 36 and the drain hole 37 with respect to the supply / discharge hole 35
Is relatively opened and closed, and is urged to the left in the drawing by the spring force of the valve spring to communicate the supply / discharge hole 35 and the drain hole 37 with each other. The opening area is variably controlled.

The electromagnetic actuator 31 is fixed to a rocker cover 38, and the amount of advance of the drive shaft 31a is controlled by the duty ratio control of a controller 39 which detects the engine operating state. The controller 3
9 is a crank angle sensor (not shown), an air flow meter,
A current engine operating state is detected based on input signals from various sensors such as a water temperature sensor and a throttle valve switch, and a control pulse signal is output to the electromagnetic actuator 31.

The operation of this embodiment will be described below.
First, when the engine is running at low speed and low load, an OFF signal is output from the controller 39 to the electromagnetic actuator 31, and the spool valve 30 closes the position shown in FIG. 2, that is, the supply hole 36 by the spring force of the valve spring, and the supply / discharge hole 35 and the drain hole. And communicate with. Therefore, the hydraulic oil in the pressure chamber 18 is not supplied to the supply / discharge passage 2
7 is discharged to the outside through the drain passage 28, and the pressure chamber 18 has a low pressure. Therefore, the cylindrical gear 14 is held on the maximum front end side via the piston 15 by the spring force of the compression spring 20, as shown in FIG. As a result, the sprocket 1 and the camshaft 2 rotate relative to one side and the phase is converted, and as a result, the opening timing of the intake valve is delayed, the valve overlap with the exhaust valve is reduced, and the combustion efficiency is reduced. Is improved, stable driving and improved fuel efficiency can be achieved.

On the other hand, when the engine low-speed low-load region is shifted to the high-speed high-load region, an ON signal having the maximum pulse width is output to the electromagnetic actuator 31, and the spool valve 30 resists the spring force of the valve spring. As shown in FIG. 3, the supply / discharge hole 35 and the drain hole 37 are closed by sliding rightward, and the supply hole 36 and the supply / discharge hole 35 are communicated with each other. As a result, the hydraulic oil pumped from the oil pump 22 is supplied to the pressure chamber 18 through the supply passage 24, the supply / discharge passage 27, the fitting groove 3b, and the passage groove 26, and the pressure chamber 18 has a high pressure. Therefore, the piston 15 moves to the maximum rightward direction and pulls the rear gear component and the front gear component in the same direction via the support pins 17 and 16. Therefore, the cylindrical gear 14
The whole is held at the maximum rightward position (position in the figure) as shown in FIG. As a result, the both 1 and 2 relatively rotate in the other direction, and the phases are oppositely converted. As a result, the opening timing and the closing timing of the intake valve are advanced, the overlap becomes large, and the output can be improved by improving the intake charging efficiency.

In addition, during medium speed, medium load, and other predetermined operating ranges, the spool valve 30 is held at an intermediate position based on a control signal from the controller 39, and the opening area of the supply / discharge hole 35 is increased to a predetermined value. Control. Therefore, the tubular gear 14 is held at a predetermined intermediate position as shown in FIG. 6, whereby the intake valve is also controlled at a predetermined opening / closing timing. Therefore, it becomes possible to sufficiently exert the engine performance according to the operating condition.

Further, in this embodiment, the oil passage structure 32
Since it is formed separately from the sprocket 1 and the like, it is not necessary to form an oil passage hole in the cylinder head 10b or the cam shaft 2, and thus the cylinder head 10b
It is possible to prevent a decrease in strength and rigidity of b, the camshaft 2, etc., and also a decrease in supporting rigidity for other parts.
As a result, engine vibration and vibration noise can be reduced.

Moreover, the oil passage structure 32 has a lower end 32.
a is simply the fixing bolt 33 and the cylinder block 10
It is fixed to a, and the upper end portion 32b is only inserted and arranged in the support hole 8a, and it is formed independently without having a close structural relationship with the sprocket 1 and the camshaft 2, and is conventionally formed. Since the hydraulic chamber is not formed and the piston and the like are not housed and held unlike the housing of No. 2, high processing accuracy and assembly accuracy are not required. As a result, the manufacturing work efficiency and the assembly work efficiency can be improved.

Moreover, the upper end portion 32b of the oil passage structure 32 is
Rotatably supports the front end portion of the sprocket 1, so that the sprocket 1 and the camshaft 2 do not fall downward due to the tension of the timing chain, and a stable horizontal posture can be maintained. Therefore, smooth operation of the tubular gear 14 is not hindered, and as a result, deterioration of the valve timing control action can be prevented.

FIG. 7 shows a second embodiment of the present invention, in which a proportional solenoid type electromagnetic actuator 31 and a rocker cover 3 are provided.
8 is provided on the side of the cylinder block 10a. Therefore, it is not necessary to provide a bulging portion for forming the valve hole in the oil passage structure 32, and the supply / discharge passage 2 is simply provided.
It only forms part of 7. On the other hand, a part of the supply / discharge passage 27, the valve hole 25, the supply passage 24, and the drain passage 28 are formed in the cylinder block 10a. As a result, the entire structure of the oil passage structure 32 is simplified and the manufacturing workability is further improved. The description of other structures is omitted because it is the same as that of the first embodiment.

8 and 9 show a third embodiment of the present invention, in which first and second pressure chambers are formed in front of and behind the piston 15,
Hydraulic pressure is relatively supplied to and discharged from each of the pressure chambers so that the cylindrical gear 14
Is to be moved forward or backward.

That is, the first pressure chamber 18 is formed on the front end side of the piston 15, the second pressure chamber 41 is formed on the rear end side of the piston in which the compression spring 40 is housed, and the cylindrical shape of the sprocket 1 is formed. A first supply / discharge hole 42 that communicates with the first pressure chamber 18 is formed on the front end side of the main body 1a, while a second bolt is formed in the inner axial direction and the radial direction of the fixing bolt 4 of the sleeve 3 and in the radial direction of the sleeve 3. The second supply / discharge hole 43 communicating with the pressure chamber 41 is formed in a substantially L shape.

Further, in the oil passage structure 32, a part 24a of the supply passage 24 is formed in a lower end portion 32a fixed to the cylinder block 10a by a bolt 33, and a valve hole 25 is formed in a bulging portion 32c. Has been formed. In addition, one branch portion 3 (the right side in the drawing) branched upward from the bulging portion 32c.
A first supply / discharge passage 27a that communicates the valve hole 25 with the first supply / discharge hole 35a is formed in 2d, and the valve hole 25 and the fitting groove 3b are formed in the other (left side in the drawing) branch portion 32e. A second supply / discharge passage 27b is formed which communicates with the second supply / discharge hole 35b via the second supply / discharge passage 27b.

The first branch portion 32d has an upper end portion 32f.
Is formed in an annular shape, the inner peripheral surface of the upper end portion 32f rotatably supports the front end side of the cylindrical main body 1a via seal rings 44, 45, and the groove groove 46 is formed on the inner peripheral surface.
Are formed.

Further, the second branch portion 32e has a passage forming portion 47 which is inserted into the upper end portion from a right angle direction, and the passage forming portion 47 has a second supply / discharge passage which communicates the fitting groove 3b therein. A portion 27c of 27b is formed, and a large diameter portion 47a at one end is screwed and fixed in the support hole 8a of the front cover 8.

A drain passage 28 is formed at the rear end of the bulging portion 32c, and each of the supply / discharge passages 27a and 27b is provided in the valve hole 25, and the supply passage 24 is provided in the drain passage 2.
8, a spool valve 30 that is switched relative to 8 is slidably provided.

This spool valve 30 has a rocker cover 38.
Proportional solenoid type electromagnetic actuator 3 fixed to
The operation of the electromagnetic actuator 31 is controlled by the control signal from the controller 1, and the duty ratio of the electromagnetic actuator 31 is controlled by the controller 39 as in the first embodiment.

The compression spring 40 is set to a small spring force that holds the cylindrical gear 14 at the maximum forward position when the electromagnetic actuator 31 is turned off.
The other structure is the same as that of the first embodiment.

Therefore, according to this embodiment, when the engine speed is low and the load is low, the electromagnetic actuator 31 is turned off, the spool valve 30 connects the supply passage 24 and the second supply / discharge passage 27b, and the first supply / discharge passage 27a. And drain passage 2
Since 8 are communicated with each other, the working oil in the first pressure chamber 18 is discharged, while the working oil is supplied in the second pressure chamber 41 via the second supply / discharge hole 43. Therefore, the piston 15
The tubular gear 14 is moved to and held at the maximum front position as shown in FIG. 9 via the, so that the relative rotational phase of the sprocket 1 and the camshaft 2 is converted to one side.

Further, at the time of high speed and high load, the spool valve 30
Moves to the right in the figure, the second pressure chamber 41 becomes low pressure, the first pressure chamber 18 becomes high pressure, and the tubular gear 14 moves to the maximum rear position. As a result, the relative rotational phase of the both 1 and 2 is converted to the other side.

Further, in a predetermined operating range of the engine, the spool valve 30 is held at a predetermined sliding position to relatively control the opening areas of the supply / discharge passages 27a and 27b.
It can be set to an arbitrary relative rotation phase.

The operation and effect of the oil passage structure 32 are similar to those of the first embodiment.

10 and 11 show a fourth embodiment of the present invention. The difference from the third embodiment is that the first feed / discharge hole 42 is formed at the front cover 8 and the front cover 8 and The structure of the oil passage structure 32 is modified. That is, the front cover 8 is formed in a substantially cylindrical shape, and the first and second supply / discharge passages 27a, 27b are formed in the upper end portion 32b of the oil passage forming body 32 that is inserted and arranged in the support hole 8a. It is formed substantially parallel and bent.
Further, the first supply / discharge hole 42 is formed in the front cover 8 in an L shape.

Therefore, according to this embodiment, the same operation as the third embodiment can be obtained, and in particular,
Since the two systems of supply / drain passages 27a and 27b are formed together in the upper end portion 32b of the oil passage structure 32, the oil passage structure 32 is prevented from becoming larger and lighter than the third embodiment. And compactness can be achieved.

[0042]

As is apparent from the above description, according to the present invention, the oil passage is not formed inside the cylinder head, the cam shaft or the like as in the conventional case, but is separated from the rotating body and the cam shaft. Because it was formed in the independent oil passage structure,
There is no need to open a hole for forming an oil passage inside the cylinder head, etc., and it is possible to prevent the strength and rigidity of the cylinder head, the cam shaft, etc. and the supporting rigidity of other parts from being lowered, and to generate vibration and vibration noise. Suppressed.

Moreover, the oil passage structure is formed independently and does not have a close relationship with a rotating body such as a hydraulic chamber or a piston for accommodating a piston or the like, a cam shaft, etc. as in the conventional case. Therefore, high processing accuracy and assembly accuracy are not required. As a result, the efficiency of manufacturing work and assembly work can be improved.

Further, since the oil passage structure body rotatably supports the front end portion of the rotating body, the rotating body and the camshaft do not fall down even if tension is applied by the timing chain, etc. Can be maintained. As a result, deterioration of the operation of the movable body is prevented, and the valve timing control action is improved.

[Brief description of drawings]

FIG. 1 is a sectional view of a main part showing a first embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of an essential part showing the operation of this embodiment.

FIG. 3 is an enlarged sectional view of an essential part showing the operation of this embodiment.

FIG. 4 is a vertical cross-sectional view showing the operation when the electromagnetic actuator of this embodiment is OFF.

FIG. 5 is a vertical cross-sectional view showing the operation when the electromagnetic actuator of this embodiment is turned on.

FIG. 6 is a vertical cross-sectional view showing the action when controlling the intermediate position of the electromagnetic actuator of the present embodiment.

FIG. 7 is a sectional view of an essential part showing a second embodiment of the present invention.

FIG. 8 is a sectional view of a main portion showing a third embodiment of the present invention.

FIG. 9 is an enlarged sectional view of a main part of the present invention.

FIG. 10 is a cross-sectional view of an essential part showing a fourth embodiment of the present invention.

FIG. 11 is an enlarged cross-sectional view of a main part of this embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Sprocket (rotating body) 2 ... Cam shaft 3 ... Sleeve 5 ... Movable body 6 ... Drive mechanism 8 ... Front cover 14 ... Cylindrical gear 15 ... Piston 18 ... Pressure chamber 19 ... Hydraulic circuit 20 ... Supply passage 24 ... Supply passage 25 ... Valve hole 27 ... Supply / discharge passage 28 ... Drain passage 30 ... Spool valve 31 ... Electromagnetic actuator 32 ... Oil passage structure 32b ... Upper end (one end)

Front page continued (72) Naoko Nagura, Inventor Naoko Nagisa, Atsugi City, Kanagawa Prefecture, 1370, Yunishia Jecs Co., Ltd. Inventor Asaichi Kobayashi 1370 Onna, Atsugi City, Kanagawa Prefecture

Claims (5)

[Claims] 1. A cam shaft for opening and closing an intake valve and an exhaust valve via a cam by a rotational force transmitted from an engine through a rotating body, and a driving shaft provided between the rotating body and the cam shaft. In a valve timing control device including a movable body that operates by hydraulic pressure supplied from a hydraulic circuit of a mechanism to convert a relative rotational phase of the rotary body and a camshaft, an oil passage of the hydraulic circuit is formed inside. The rotating body and the cam shaft are formed independently of each other, and one end of the rotating body is slidably inserted into the front end of the rotating body to form the rotating body. A valve timing control device for an internal combustion engine, wherein a front end portion of the engine is rotatably supported. 2. The valve timing control device for an internal combustion engine according to claim 1, wherein the movable body is operated by a relative pressure between a hydraulic pressure of the hydraulic circuit and a spring force of a spring member. 3. The valve timing control device for an internal combustion engine according to claim 1, wherein the movable body is operated by a relative hydraulic pressure acting from the hydraulic circuit to the front and rear of the movable body. 4. The movable body is turned on via a hydraulic circuit.
2. The valve timing control device for an internal combustion engine according to claim 1, wherein the valve timing control device is operated by an OFF two-stage switching control. 5. The valve timing control device for an internal combustion engine according to claim 1, wherein the movable body is operated and controlled in multiple stages via a proportional solenoid type electromagnetic actuator provided in a hydraulic circuit.