JPH09228810A - Valve timing control device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent deterioration in controlling capability which is caused by vibration in the axial direction of a cam shaft. SOLUTION: A cylindrical member 17 is integratedly and rotatably connected to the top end part of an intake side cam shaft 11. A cylindrical valve element 18 is rotatably arranged on the inner part of the cylindrical member 17. A driving motor 47 for rotatably driving the valve element 18 is installed on a head cover 46. A sprocket 19 hung a chain 78 is rotatably fitted around the outer peripheral part of the cylindrical member 17. A piston gear 21 is arranged between the cylindrical member 17 and a cover 20 connected to the sprocket 19, and the gear 21 is engaged with the cylindrical member 17 and the sprocket 19 by helical teeth 40, 41. An advance angle side oil pressure chamber 44 and a delay angle side oil pressure chamber 45 are arranged on the top end side and a base end side of the piston gear 21. The valve element 18 is rotated, and thereby, oil pressure are regulated in the oil pressure chambers 44, 45.

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 controlling opening / closing timing of intake / exhaust valves of an internal combustion engine, that is, valve opening / closing timing.

[0002]

2. Description of the Related Art Conventionally, as a valve timing control device for changing the opening / closing timing of an intake / exhaust valve of an internal combustion engine in accordance with the operating state of the engine, for example, Japanese Patent Laid-Open No. Hei.
The one described in Japanese Patent No. 33617 is known.
The valve timing control device described in the publication is shown in FIG.
As shown in FIG. 1, a sprocket 90 to which a rotational driving force of a crankshaft (not shown) is transmitted, a front cover 91 provided at a tip portion of the sprocket 90, and a rotational force transmitted from the sprocket 90 are used to intake air. And a cam shaft 92 for opening and closing a valve (not shown). A holding member 93, an arm 94 fitted to the leading end of the holding member 93, and a tubular portion 95 are respectively screwed to the tip end side (left side in FIG. 11) of the cam shaft 92 by bolts 96.

An annular piston 97, which is movable in the axial direction of the cam shaft 92, is provided between the sprocket 90 and the tubular portion 95. The piston 97 has a tip end side and a base end side. Is the first pressure chamber 98 and the second pressure chamber 9
9 are formed. A plurality of sliders 100 are provided on the base end surface of the piston 97 at equal intervals in the circumferential direction.
Are formed respectively. Further, the holding member 93 has a pair of extending portions 1 extending in the radial direction of the cam shaft 92.
01 is formed. Each of the sliders 100 is in contact with each of the extending portions 101 by an inclined surface, and
When 7 moves in the axial direction of the cam shaft 92 by the hydraulic pressure supplied to the pressure chambers 98, 99, the shaft 9
A rotational force about the same axis is applied to 2 to rotate. As a result, the rotational phase of the cam shaft 92 and the sprocket 90 changes, and the opening / closing timing of the intake valve changes.

A movable member is provided on the inner periphery of the tubular portion 95 so as to be slidable in the axial direction of the cam shaft 92. Further, a switching valve 103 which is slidable in the axial direction is provided inside the movable member 102.
The valve body 103a of No. 03 is driven in the axial direction of the cam shaft 92 by an electromagnetic actuator (not shown) via the drive rod 104.

In the above-mentioned prior art, the valve member 103a of the switching valve 103 is moved in the axial direction of the camshaft 92 by the electromagnetic actuator, and the holding member 93 and the valve member 1 are moved.
By switching the communication state of the hydraulic passage formed at 03a, the supply and discharge states of oil in the pressure chambers 98 and 99 are changed according to the operating state of the engine. As a result, the piston 97 is moved to each pressure chamber 9
Camshaft 92 depending on the oil pressure in
In the axial direction, the rotation phase of the shaft 92 is changed by this movement, and the opening / closing timing of the intake valve can be controlled.

[0006]

SUMMARY OF THE INVENTION The camshaft 92
Is normally supported by the engine body, and its radial position is designed to be fixed with respect to the engine body.However, if there is a slight change in the axial position due to errors during machining or assembly tolerances, etc. Yes, but acceptable.
As a result, the camshaft 92 may vibrate in the axial direction due to various exciting forces generated during the operation of the engine.

In the above-mentioned prior art, the camshaft 92
When the vibration as described above is input to the shaft 92,
The relative positional relationship between the valve element 103a and the holding member 93 in the axial direction of is changed, the switching of the hydraulic passage by the switching valve 103 is not normally performed, and the controllability of the valve timing control device is deteriorated. was there.

The present invention has been made in view of the circumstances, and an object thereof is to provide a valve timing of an internal combustion engine capable of preventing deterioration of controllability due to vibration in the axial direction of a camshaft. It is to provide a control device.

[0009]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention relates to a cam shaft rotatably supported by an engine body for driving a valve to open and close, and a cam shaft provided on the cam shaft for rotationally driving an engine. A rotary body that transmits a rotational driving force to the camshaft while transmitting a force, and a pressure chamber to which a pressurized fluid is supplied, and the camshaft and the rotary body are formed by the pressure of the fluid in the pressure chamber. And a pressure passage for supplying a fluid from a pressurized fluid supply source to the pressure chamber and discharging the fluid from the pressure chamber. A switching valve provided in the middle of the pressure passage for adjusting the pressure of the fluid in the pressure chamber, and a drive control means for driving and controlling the switching valve according to the operating state of the internal combustion engine. In the valve timing control device for an engine, the switching valve includes a housing and a valve body that is provided in the housing and is rotatable about an axis parallel to the axis of the camshaft as a rotation axis. The gist of the invention is to switch the flow state of the fluid in the pressure passage by changing the relative rotational phase of the valve body with respect to the housing.

(Operation) According to the first aspect of the invention, the camshaft rotatably supported by the engine body is rotated by the rotational force transmitted from the rotating body provided on the shaft. Then, as the camshaft rotates, the valve of the engine is opened and closed.

The valve body of the switching valve provided in the middle of the pressure passage is rotationally driven by the drive control means according to the operating state of the internal combustion engine. As a result, the relative rotational phase of the valve element with respect to the housing is changed, and the fluid circulation state in the pressure passage is switched between a state in which the fluid is supplied to the pressure chamber and a state in which the fluid is discharged from the pressure chamber. To be

The pressure of the fluid in the pressure chamber is adjusted by switching the flow state of the fluid in the pressure passage by the switching valve. The phase changing means relatively rotates the camshaft and the rotating body by the adjusted fluid pressure, and changes the rotational phase of the camshaft. As a result, the valve opening / closing timing in the internal combustion engine is changed according to the operating state of the engine.

As described above, in the present invention, the valve opening / closing timing is changed by rotating the valve element about the axis parallel to the axis of the camshaft as the rotation axis, and changing the relative rotational phase of the valve element and the housing. Is done by doing. That is,
According to the present invention, even when the vibration in the axial direction of the camshaft is input to the housing or the valve element and the relative positional relationship between the two changes in the coaxial direction, the change in the positional relationship causes a change in the fluid in the pressure passage. It does not directly affect the distribution status. As a result, the pressure adjusting operation of the pressure chamber by the switching valve is normally performed.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment in which the present invention is embodied as a valve timing control device provided in a gasoline engine will be described below with reference to FIGS.

FIG. 1 shows an intake side camshaft 11 (hereinafter referred to as "camshaft") for opening and closing an intake valve (not shown) provided in an engine as an internal combustion engine, and an end portion of the shaft 11. Valve timing changing mechanism 12 (hereinafter,
FIG. 2 is a partially enlarged sectional view of FIG. 1 showing a “VVT mechanism”).

The tip side of the camshaft 11 (left side in FIG. 1)
A flange 13 is formed on the front end of the flange 13, and a columnar connecting portion 14 is formed on the tip side of the flange 13. The cam shaft 11 is rotatably supported by the upper end portion of the engine cylinder head 14 and the bearing cap 16 at the journal portion 11 a between the flange 13 and the connecting portion 14. A cam (not shown) for opening and closing an intake valve (not shown) provided for each cylinder of the engine is formed on the base end side (right side in FIG. 1) of the camshaft 11.

The VVT mechanism 12 is composed of a switching valve 23 including a tubular member 17 as a housing and a valve body 18, a sprocket 19 as a rotating body, a cover 20, a piston gear 21 and the like. The connection portion 14
Has a mounting hole 22 having a step portion 22a from its tip side.
Are formed. The base end portion of the cylindrical member 17 having a cylindrical shape is fitted in the mounting hole 22.
The most proximal end of 7 is screwed and fixed in the mounting hole 22.
Therefore, the tubular member 17 can rotate integrally with the cam shaft 11.

An insertion hole 24 having a circular cross section is formed inside the cylindrical member 17, and the cylindrical valve body 18 is inserted in the insertion hole 24. This valve body 18
A bearing 25 is disposed between the outer peripheral portion of the valve body 18 and the inner peripheral portion of the insertion hole 24.
It is rotatably supported by 5.

An internal space 26 extending in the axial direction is formed in the valve body 18, and a rod-shaped torsion bar 27 is arranged in the space 26. In this torsion bar 27, columnar connecting portions 28 and 29 are formed on both ends thereof, and each connecting portion 2 is formed.
A reduced diameter portion 30 is formed between 8 and 29. The tip side connecting portion 28 of the torsion bar 27 is inserted into the fixing hole 31 formed in the valve body 18, and the knock pin 3
It is fixed to the valve body 18 by 2. Therefore,
The tip-side connecting portion 28 can rotate integrally with the valve body 18. Further, the base end side connecting portion 29 is press-fitted and fixed in a fixing hole 33 formed in the tubular member 17, and is integrally rotatable with the valve body 18. A switching valve 23 is formed by the tubular member 17, the valve element 18, and the torsion bar 27.

Further, the torsion bar 27 is adjusted in its torsional rigidity by forming the reduced diameter portion 30,
When a twisting torque is input from each of the connecting portions 28 and 29, a twisting deformation is generated according to the magnitude of the torque. The valve body 18 is rotatable relative to the tubular member 17 by allowing the torsion bar to undergo such torsional deformation.

An annular sprocket 19 is fitted on the outer periphery of the tubular member 17 on the tip side of the camshaft 11 so as to be rotatable relative to the member 17. A sprocket 19 is formed with an outer peripheral portion 19a, and a timing chain 78 is hooked on the tooth 19a. The timing chain 78 is mounted on a crank sprocket (not shown) of the crankshaft, and the rotational driving force of the crankshaft is transmitted to the camshaft 11 via the timing chain 78. Then, when the camshaft 11 is rotated by the transmitted rotational driving force, the intake valve is opened / closed with the rotation.

The cover 20 has a bottomed cylindrical shape having a step portion 20a, and a center hole 34 is formed at the tip thereof. The valve body 18 is loosely inserted in the center hole 34. A flange 35 is formed on the outer periphery of the cover 20 on the base end side. The flange 13 is overlapped with the front end surface of the sprocket 19 and is fixed to the sprocket 19 by a plurality of bolts 36.

The inner peripheral wall of the cover 20, the sprocket 1
An annular accommodation space 37 is defined by the front end surface of 9 and the outer peripheral wall of the tubular member 17. A piston gear 21 having a substantially annular shape is arranged in the accommodation space 37. The piston gear 21 is composed of a movable portion 38 having a cylindrical shape, and a pressure receiving portion 39 extending from the base end portion of the movable portion 38 in the radial direction of the camshaft 11.

Helical teeth 40 and 41, which are inclined with respect to the axis of the cam shaft 11, are formed on the inner and outer peripheral portions of the movable portion 38 on the tip side. Further, inner teeth 42 and outer teeth 43, which are also helical teeth, are formed on the inner peripheral wall of the cover 20 on the tip side of the step portion 20a and the outer peripheral wall of the tubular member 17, respectively. Then, the helical teeth 4 formed on the outer peripheral side of the movable portion 38.
Reference numeral 1 is an inner tooth 42 of the cover 20, and helical tooth 40 formed on the inner peripheral side of the movable portion 38 is an outer tooth 43 of the tubular member 17.
Are meshed with each other.

The accommodation space 37 is divided into two pressure chambers by the piston gear 21. Piston gear 2
The space on the front end side of 1 constitutes the advance side hydraulic chamber 44, and the space on the base end side forms the retard side hydraulic chamber 45. The lubricating oil for the engine is supplied into each of the hydraulic chambers 44 and 45 through an advance-side control oil passage and a retard-side control oil passage as described later. The piston gear 21 is provided in each hydraulic chamber 4
The camshafts 11 are urged by the hydraulic pressures at 4 and 45 to move to the front end side or the base end side of the camshaft 11. When the piston gear 21 moves in this way, the cover 20 and the tubular member 1
Since 7 is meshed with the gear 21 by helical teeth 40 and 41, both 20 and 17 rotate relatively. As a result, the rotational phase of the camshaft 11 fixed to the tubular member 17 is the same as that of the sprocket 19 fixed to the cover 20.
Will be changed relative to.

As shown in FIG. 1, a head cover 46 is attached to the cylinder head 14 so as to cover the tip portion of the cam shaft 11 and the VVT mechanism 12. A through hole 46a is formed in a portion of the head cover 46 corresponding to the side portion of the VVT mechanism 12.
The tip side portion of the valve body 18 is inserted into the through hole 46a and projects to the outside of the head cover 46. or,
A rotor coil 48 forming a part of a drive motor 47 described later is provided on the outer peripheral portion of the most distal end portion of the valve body 18.

The head cover 46 has the same cover 46.
A drive motor 47 is attached so as to cover the tip portion of the valve element 18 protruding from the valve motor 18. More specifically, a mounting flange 50 is formed on the housing 49 of the drive motor 47, and the flange 13 is fixed to the head cover 46 by a plurality of bolts 51. A stator coil 52 is arranged inside the head cover 46, and the rotor coil 48 is arranged inside the stator coil 52.

The drive motor 47 generates an electromagnetic force according to the magnitude of the supplied current in the stator coil 52, and causes the electromagnetic force to act on the rotor coil 48, whereby the camshaft 11 is moved relative to the valve body 18. It is possible to give a rotational torque in both directions around the axis.

Further, in the present embodiment, the drive motor 4
The electronic control unit 7 is controlled by an electronic control unit (hereinafter referred to as “ECU”) 53. The ECU 53 includes a central processing unit (hereinafter referred to as “CPU”), a read-only memory (hereinafter referred to as “ROM”), a random access memory, a backup memory and the like (none of which is shown). The ECU 53 is composed of a logical operation circuit in which these units, an input interface, an output interface and the like (none of which are shown) are connected by a bidirectional bus.

A rotation speed sensor 54 for detecting the engine speed and an intake pressure sensor 55 for detecting the intake pressure in the intake passage are connected to the input interface, as well as a crank angle sensor and a cam angle sensor. (Neither is shown) or the like is connected. The drive motor 47 is connected to the output interface.
In the present embodiment, the rotation speed sensor 54 and the intake pressure sensor 55 constitute an operation state detecting means for detecting the operation state of the engine.

The ROM stores, as numerical data, the relationship between the engine rotational speed and the intake pressure, which are parameters indicating the operating state of the engine, and the target rotational phase angle of the camshaft 11. Based on this numerical data, the CPU causes the actual rotation phase angle of the camshaft 11 (hereinafter referred to as “actual rotation phase angle”) detected from the input signal of the cam angle sensor or the like to match the target rotation phase angle. To control. The drive motor 47 and the ECU 53 constitute drive control means.

Next, the advance side hydraulic passage, the retard side hydraulic passage for adjusting the hydraulic pressure of the lubricating oil in the advance side hydraulic chamber 44 and the retard side hydraulic chamber 45, and the lubrication in each of these hydraulic passages. The supply hydraulic passage for supplying the oil and the discharge hydraulic passage for discharging the lubricating oil from each hydraulic passage will be described.

A head oil passage 56 is formed inside the cylinder head 14. The head oil passage 56 includes an oil filter 57 and an oil pump 5 as a pressurized fluid supply source.
8 and the oil pan 60 via the oil strainer 59
It is connected to the. When the oil pump 58 is driven along with the operation of the engine, the lubricating oil as a fluid stored in the oil pan 60 is sucked by the pump 58. Then, the lubricating oil is introduced into the oil pump 58 through the strainer 59 and is discharged from the pump 58 under pressure. The discharged lubricating oil is supplied into the head oil passage 56 through the oil filter 57.

At the upper end of the cylinder head 14, a semicircular oil groove 6 is formed at the opening position of the head oil passage 56.
1 is formed. A similar oil groove 62 is also formed in the bearing cap 16.

Inside the camshaft 11, a shaft oil passage 63 extending in the axial direction is formed. Further, inside the camshaft 11, a pair of supply oil holes 64 extending in the radial direction of the shaft 11 are formed. The shaft oil passage 63 and the oil grooves 6 are formed by the supply oil holes 64.
1, 62 communicate with each other.

A first oil supply passage 65 extending in the axial direction of the camshaft 11 is formed inside the tubular member 17. The tip end side of the first oil supply passage 65 is closed by the base end side connecting portion 29 fixed in the fixing hole 33, and the base end side of the passage 65 communicates with the shaft oil passage 63. . Inside the tubular member 17, a pair of second oil supply passages 66 extending parallel to the first oil supply passage 65 is further provided.
Are formed. The second oil supply passages 66 and the first oil supply passages 65 are communicated with each other by a pair of communication passages 67 extending in the radial direction of the tubular member 17. The communication passage 67 is open at the outer peripheral wall of the tubular member 17, and the lubricating oil in the passage 67 is used to lubricate the contact surface between the tubular member 17 and the sprocket 19.

FIG. 5 is a sectional view taken along line VV of FIG. FIG.
The piston gear 21 is not shown in FIG. FIG.
As shown in FIG. 7, oil grooves that extend in the axial direction of the cam shaft 11 and have a rectangular cross section are formed on the outer peripheral portion of the tubular member 17 at intervals of 90 ° about the same axis. In FIG. 5, the pair of upper and lower oil grooves is a supply oil groove 68, and the pair of left and right oil grooves is a discharge oil groove 69.

Inside the tubular member 17, each of the second
At the position corresponding to the tip of the oil supply passage 66, the member 1
A pair of oil holes 70 are provided from the outer peripheral portion of 7 toward the inside. The second oil supply passage 66 is provided through these oil holes 70.
The lubricating oil is supplied into each oil supply groove 68. A spherical seal member 7 is provided inside each oil hole 70.
1 are provided respectively, and the respective oil holes 70 are closed by the respective members 71 in the vicinity of the outer peripheral wall of the tubular member 17. The head oil passage 56, the pair of supply oil holes 64, the shaft oil passage 63, the first oil supply passage 65, the pair of communication passages 6
7, the pair of second oil supply passages 66, and the pair of oil holes 70 form a supply hydraulic passage.

As shown in FIG. 5, each drain oil groove 69 is formed.
Is the inner space 2 of the valve body 18 due to the pair of drain oil holes 72.
It is in communication with 6. In addition, as shown in FIG.
At the tip end side of the valve body 18, the outside of the valve body 18 and the internal space 2
A pair of drain holes 73 communicating with 6 are formed.
The lubricating oil that has flowed into the internal space 26 from the respective drain oil grooves 69 through the respective drain oil holes 72 is discharged to the outside of the valve body 18 through the respective drain holes 73. The lubricating oil discharged to the outside of the valve body 18 in this way is stored in the oil pan 60.
Is to be returned to. The pair of drain oil grooves 6
9, drain oil hole 72, internal space 26, and drain hole 7
The discharge hydraulic passage is constituted by 3.

On the inner peripheral wall of the tubular member 17, at a position rotated by 45 ° clockwise with respect to each oil hole 70, a rectangular cross section is formed as shown in FIG. A pair of extending oil grooves 74 on the advance side are formed. Each advance side oil groove 74 communicates with the advance side hydraulic chamber 44 by an advance side oil hole 75 extending in the radial direction of the camshaft 11. The pair of advance side oil grooves 74 and the advance side oil holes 75 form an advance side hydraulic passage.

45 counterclockwise with respect to each oil hole 70.
A retard angle oil groove 76 having the same shape as the advance angle oil groove 74 is formed at the position rotated by °. Each retard side oil groove 76 is a pair of retard side oil holes 77 extending in the radial direction of the camshaft 11.
Communicates with the retard side hydraulic chamber 45. The pair of retard side oil grooves 76 and the retard side oil holes 77 form a retard side hydraulic passage.

The pressure passage in the present invention is constituted by the supply and discharge side hydraulic passages and the advance and retard side hydraulic passages described above. Next, the operation of the present embodiment configured as described above will be described.

When the engine is started, the lubricating oil in the oil pan 60 is sucked by the oil pump 58 via the oil strainer 59 and is discharged from the pump 58 in a pressurized state. The lubricating oil discharged from the oil pump 58 is supplied into the head oil passage 56 through the oil filter 57, and the oil grooves 61, 62,
And is supplied into the shaft oil passage 63 through each oil supply hole 64. Further, the lubricating oil supplied into the shaft oil passage 63 is supplied into the oil supply groove 68 through the first oil supply passage 65, each communication passage 67, each second oil supply passage 66, and each oil hole 70. .

Further, the rotational driving force of the crankshaft is transmitted to the sprocket 19 via the timing chain 78. The rotational driving force transmitted to the sprocket 19 is
It is transmitted to the camshaft 11 via the cover 20, the piston gear 21, and the tubular member 17, and the shaft 11 is rotationally driven. The intake valve of the engine is opened / closed as the camshaft 11 rotates.

Further, the rotational driving force transmitted to the tubular member 17 is transmitted to the valve body 18 via the torsion bar 27. Therefore, the valve body 18 is rotationally driven together with the camshaft 11. Further, the rotor coil 48 provided on the tip end side of the valve body 18 has the stator coil 5 inside the drive motor 47.
It is driven to rotate relative to 2.

Here, the CPU of the ECU 53 detects the engine speed and the intake pressure based on the input signals from the speed sensor 54 and the intake pressure sensor 55. And
The CPU reads the target rotation phase angle corresponding to the detected engine speed and intake pressure from the numerical data stored in the ROM, and compares the target rotation phase angle with the actual rotation phase angle of the camshaft 11. .

When the deviation between the actual rotation phase angle of the camshaft 11 and the target rotation phase angle is less than the predetermined angle, the CPU does not control the energization of the drive motor 47. Therefore, since the electric current is not supplied to the stator coil 52 of the drive motor 47, the valve body 18 does not obtain the rotational torque from the rotor coil 48. Therefore,
The valve body 18, the tubular member 17, the sprocket 19, and the camshaft 11 are all integrated and rotate in the direction indicated by arrow A in FIG. In this case, the tubular member 17 and the valve body 18
Maintain the positional relationship as shown in FIG. 5 in the axial direction of the camshaft 11. (Hereinafter, shown in FIG.
The position of the valve element 18 with respect to the tubular member 17 around the axis of the cam shaft 11 is referred to as an "intermediate holding position". ) That is,
Each supply oil groove 68 formed in the valve body 18 faces the opening of each oil hole 70 communicating with the second oil supply passage 66, and communicates only with each oil hole 70. Further, each of the discharge oil grooves 69 has an advance angle side oil groove 74 and a retard angle side oil groove 76.
I am not familiar with any of the above. For this reason, when the position of the valve body 18 is in the "intermediate holding position", the lubricating oil is not supplied to the advance side hydraulic chamber 44 and the retard side hydraulic chamber 45, and each hydraulic pressure is not supplied. The lubricating oil will not be discharged from the chambers 44 and 45.

Therefore, the hydraulic pressure in the hydraulic chambers 44 and 45 does not change, and the piston gear 21 moves to the hydraulic chambers 44 and 4 respectively.
Since the urging force received from the hydraulic pressure of 5 is balanced, the gear 21 does not move in the axial direction of the camshaft 11.

Next, the actual rotation phase angle of the camshaft 11 is advanced from the state where the position of the valve body 18 is in the "intermediate holding position" and the actual rotation phase angle of the camshaft 11 is not changed. The case of performing, that is, the case of controlling the advance angle will be described.

When the CPU determines that the absolute deviation between the actual rotation phase angle of the camshaft 11 and the target rotation phase angle is more than a predetermined angle and the actual rotation phase angle is behind the target rotation phase angle, the drive The motor 47 is energized to supply a predetermined current to the stator coil 52. The stator coil 52 is attached to the valve body 18 provided with the rotor coil 48.
Rotational torque is generated according to the magnitude of the current supplied to the. In this way, when the rotational torque acts on the valve element 18, the torsion bar 27 is twisted and deformed by the amount of strain according to the magnitude of the rotational torque. As a result, the valve body 18
Rotates relative to the tubular member 17 and the positional relationship between the camshaft 11 and the camshaft 11 changes in the axial direction.

FIG. 8 shows the magnitude of the rotational torque acting on the valve body 18 and the relative rotation angle of the valve body 18 with respect to the tubular member 17. When advancing the actual rotation phase angle of the camshaft 11, the CPU supplies a positive current to the stator coil 52 of the drive motor 47. Then, a rotational torque having a magnitude proportional to the magnitude of the current value is applied to the valve body 18 in a direction indicated by an arrow A in FIG. 5 (the direction of this rotational torque is referred to as “forward direction”, which is opposite to the “forward direction”). The direction of the rotational torque of the direction is referred to as “negative direction”), and the rotational torque causes the valve body 18 to rotate in the same direction.

As a result, the position of the valve body 18 in the axial direction of the camshaft 11 is changed from the "intermediate holding position" to the "advance angle control position" shown in FIG. Thus, when the valve body 18 rotates relative to the tubular member 17, as shown in the figure, the supply oil grooves 68 of the valve body 18 communicate with the advance side oil grooves 74, respectively. It will be in a state of being Therefore,
Lubricating oil is introduced from each supply oil groove 68 into each advance angle oil groove 74, and is also supplied to each advance angle hydraulic chamber 44 through each advance angle oil hole 75.

On the other hand, the respective oil discharge grooves 69 are in communication with the respective retard oil grooves 76 as shown in FIG. Therefore, the lubricating oil in the retard side hydraulic chamber 45 is supplied to the respective retard side oil holes 7
7 and each retard angle side oil groove 76, and the internal space 26 through each discharge oil groove 69 and discharge oil hole 72.
Will be introduced. Then, the lubricating oil passes through the drain holes 73 from the internal space 26 and is discharged to the outside of the valve body 18. The lubricating oil discharged from the drain hole 73 is the oil pan 6
After returning to 0, the oil is again discharged from the oil pump 58 to the head oil passage 56.

As described above, when the position of the valve body 18 in the switching valve 23 becomes the "advance control position",
Lubricating oil is supplied to the advance side hydraulic chamber 44 via the advance side control oil passage, while lubricating oil in the retard side hydraulic chamber 45 is discharged via the retard side control oil passage. As a result, the oil pressure in the advance side hydraulic chamber 44 is relatively increased as compared with the oil pressure in the retard side hydraulic chamber 45.
As shown by the arrow in FIG. 3, the hydraulic pressure in the advance side hydraulic chamber 44 causes the camshaft 11 to move toward the base end side in the axial direction.

As described above, the piston gear 21 has the helical teeth 4 with respect to the cover 20 and the tubular member 17, respectively.
Piston gear 2 because it is meshed with 0, 41
The movement of 1 causes the tubular member 17 to rotate relative to the cover 20. Then, as a result of the rotation phase of the camshaft 11 rotating integrally with the tubular member 17 being advanced relative to the sprocket 19 rotating integrally with the cover 20, the opening / closing timing of the intake valve is advanced.

Next, from the state in which the position of the valve body 18 is in the "intermediate holding position" and the actual rotation phase angle of the camshaft 11 is not changed, the actual rotation phase angle of the camshaft 11 is retarded. A case of performing, that is, a case of performing retard control will be described.

When the CPU determines that the absolute deviation between the actual rotation phase angle of the camshaft 11 and the target rotation phase angle is greater than a predetermined angle and the actual rotation phase angle is ahead of the target rotation phase angle, the drive The motor 47 is energized to supply a negative current to the stator coil 52 in the opposite direction to the case of the advance angle control described above. In this way, the stator coil 5
When a negative current is supplied to the valve 2, a rotational torque having a magnitude proportional to the magnitude of the current value acts on the valve element 18. In this case, the direction of the rotational torque acts in the negative direction, which is opposite to that in the advance angle control. For this reason, the torsion bar 27 is twisted and deformed in the reverse rotation direction as compared with the case of the advance angle control by the amount of strain according to the magnitude of the rotation torque thereof, so that the position of the valve element 18 is the "intermediate holding position". The state is changed to the "retard control position" shown in FIG.

As a result, as shown in the figure, the supply oil grooves 68 of the valve body 18 are in communication with the oil holes formed in the tubular member 17 and the retard side oil grooves 76, respectively. . Therefore, the lubricating oil is introduced from each supply oil groove 68 into each retard side oil groove 76, and is supplied to each retard side oil hole 77 to the retard side hydraulic chamber 45.

On the other hand, the drain oil grooves 69 are in communication with the advance-side oil grooves 74 as shown in FIG. Therefore, the lubricating oil in the advance-side hydraulic chamber 44 passes through the advance-side oil grooves 74 and the advance-side oil holes 75, and also through the discharge oil grooves 69 and the discharge oil holes 72. It is introduced into the space 26. Then, the lubricating oil is discharged from the internal space 26 to the outside of the valve body 18 through the drain holes 73.

As described above, since the position of the valve element 18 in the switching valve 23 becomes the "retard control position",
Lubricating oil is supplied to the retard side hydraulic chamber 45 via the retard side control oil passage, while lubricating oil in the advance side hydraulic chamber 44 is discharged via the advance side control oil passage. Contrary to the case of the "advance control", the oil pressure in the retard side hydraulic chamber 45 is relatively increased as compared with the oil pressure in the advance side hydraulic chamber 44, so that the piston gear 21 is retarded. The hydraulic pressure in the side hydraulic chamber 45 causes the cam shaft 11 to move to the tip side. As a result, the rotation phase of the camshaft 11 is delayed relative to the sprocket 19, and as a result, the opening / closing timing of the intake valve is delayed.

As described above, in the present embodiment, the valve body 18 of the switching valve 23 is rotated about the axis of the camshaft 11 so that the supply-side and discharge-side hydraulic passages and the advance-side and retard-side hydraulic passages. The communication state with the control oil passage is switched according to the operating state of the engine. Then, the hydraulic pressure of the lubricating oil in each hydraulic chamber 44, 45 is adjusted, and the piston gear 21 is moved.

Further, when the piston gear 21 moves to a predetermined position, that is, when the actual rotation phase angle of the camshaft 11 becomes substantially equal to the target rotation phase angle, the CPU stops the energization control of the drive motor 47. As a result, the rotational torque in the positive and negative directions acting on the valve body 18 from the drive motor 47 disappears, so that the valve body 18 is in the “advance control position” or the “retard control position” shown in FIGS. From the above, the torsion bar 27 is rotated by the twisting force when returning to the initial state, and becomes the state of the "intermediate holding position" shown in FIG. By setting the position of the valve body 18 to the “intermediate holding position”,
The operation of changing the opening / closing timing of the intake valve ends. That is, the valve timing at that time is held until the advance or retard control is performed again. In this embodiment, as described above, the opening / closing timing of the intake valve is continuously changed by switching the position of the valve element 18 to the “advance control position”, the “retard control position”, and the “intermediate holding position”. It can be controlled steplessly.

The present embodiment described above has the following features. (A) In the present embodiment, the valve timing is changed by rotating the valve body 18 of the switching valve 23 around the axis of the camshaft 11 so as to advance and retard the control oil passages, and supply and discharge sides. This is performed by switching the communication state with the hydraulic passage.

Therefore, the camshaft 11 is apt to generate vibration in its axial direction, but according to the present embodiment, the vibration is generated from the camshaft 11 by the cylindrical member 1.
7 or even when it is transmitted to the valve body 18, the opening degree of the switching valve 23, that is, the positional relationship between the tubular member 17 and the valve body 18 in the axial direction of the shaft changes due to the vibration. It rarely happens. As a result, it is possible to prevent the controllability in the valve timing control from being deteriorated due to the vibration generated in the axial direction of the camshaft 11. Further, as a result that the valve timing can be accurately controlled, it is possible to increase the engine output by improving the intake charging efficiency and the like.

(B) Conventionally, since the valve timing is changed by moving the valve body of the switching valve in the axial direction of the camshaft, the valve body can be driven in the axial direction of the camshaft. Electromagnetic actuator was needed. Therefore, this electromagnetic actuator must have a length that is at least longer than the moving distance of the valve element, which leads to an increase in the size of the actuator and an increase in the size of the engine.

However, according to the present embodiment, the valve timing is changed by rotating the valve body 18 of the switching valve 23 around the axis of the cam shaft 11 by the drive motor 47, which is different from the conventional case. ,
The travel distance of the valve body 18 does not restrict the miniaturization of the drive motor 47. As a result, it is possible to reduce the size of the camshaft 11 of the valve timing control device in the axial direction.

(C) In this embodiment, a switching valve 23 for switching the communication state between the advance side and retard side control oil passages and the supply side and discharge side hydraulic passages is provided inside the VVT mechanism 12. The structure is provided in the corresponding cover 20.
By adopting such a configuration, each hydraulic chamber 44,
It is possible to simplify the hydraulic path for supplying the lubricating oil to 45 or discharging the lubricating oil from the hydraulic chambers 44 and 45, and it is possible to prevent the engine from increasing in size.

For example, when the switching valve 23 is arranged on the upstream side of the head oil passage 56, the advance side and retard side hydraulic chambers 44 and 45 communicate with the downstream side of the valve 23. It is necessary to provide two oil passages. Therefore, the number of oil passages corresponding to the head oil passage 56 or the shaft oil passage 63 formed inside the cylinder head 14 or the camshaft 11 increases, and the hydraulic passage is complicated.
In addition, for example, it is necessary to add an oil passage or oil groove similar to the head oil passage 56 or the oil groove 61 shown in FIG. 1 to the cylinder head 14, which increases the journal width of the camshaft 11 and inevitably results. This results in a larger engine.

On the other hand, according to the structure of the present embodiment, the switching valve 23 is arranged inside the VVT mechanism 12, and the position of the valve 23 is close to the hydraulic chambers 44 and 45. The oil passage in the head 14 or the camshaft 11 will not be increased, and the engine will not be upsized.

(D) The torsion bar 2 in this embodiment.
By adopting 7, it is possible to obtain the following effects. First, when there is no need to change the valve timing, the valve element 18 is placed in the "intermediate holding position" by the torsion bar 27. That is, it is not necessary to supply current to the stator coil 52 of the drive motor 47 to rotationally drive the valve body 18 and control the valve body 18 to the "intermediate holding position". Therefore, the power consumption of the valve timing control device can be reduced.

Secondly, since the cylindrical member 17 and the valve body 18 are connected by the torsion bar 27 and the rotational driving force of the camshaft 11 is transmitted to the valve body 18 via the torsion bar 27, the valve body is formed. 18 can be rotated at the same rotation speed as the camshaft 11.

For example, if the valve body 18 is not connected to the cylindrical member 17 without using the torsion bar 27, the rotation of the camshaft 11 is always detected and
The drive motor 47 needs to rotate the valve body 18 in synchronization with the rotation of the shaft 11. However, according to the present embodiment, since there is no such need, the configuration of the valve timing control device can be simplified.

Although the embodiment in which the present invention is embodied has been described above, the present invention can be implemented as another embodiment described below. (1) In the above-described embodiment, the advance side and retard side hydraulic chambers 44, 4 provided at the tip end side and the base end side of the piston gear 21.
The VVT mechanism 12 that changes the valve opening / closing timing by adjusting the hydraulic pressure of No. 5 and moving the gear 21 in the axial direction of the camshaft 11 has the valve opening / closing timing that can be adopted in the present invention. The mechanism to be changed is not limited to the VVT mechanism 12 described above, and for example, the configuration shown in FIG. 9 can be adopted.
9 is a camshaft 11 and V corresponding to FIGS.
It is a cross-sectional view of the VT mechanism 12, and the components corresponding to those in the above-described embodiment are designated by the same reference numerals.

As shown in the figure, the piston gear 21 in the above embodiment is omitted, and the tubular member 17 is used.
A pair of vanes 80 extending in the radial direction are formed on the outer peripheral wall of the. In addition, a pair of extending portions 81 are formed on the inner peripheral wall of the cover 20. Then, the vane 80 and the extension portion 81
The space sandwiched by the side walls of the pair of advancing-side hydraulic chambers 44 and the advancing-side hydraulic chambers 45 is similar to the above embodiment.
To form

Further, inside the cylindrical member 17, as in the above embodiment, a pair of advance side oil grooves 82 and advance side oil holes 83, and a pair of retard side oil grooves 84 and retard angles. The side oil hole 85 is formed. The advance-side hydraulic chambers 44 are formed with the advance-side oil holes 83 and the retard-side hydraulic chambers 45.
The retard side oil holes 85 are opened in the chamber.

According to this structure, the lubricating oil is supplied to the hydraulic chambers 44 and 45 through the advance-side and retard-side oil holes 83 and 85, or the lubricating oil is supplied from the hydraulic chambers 44 and 45. By being discharged, the hydraulic pressure of the lubricating oil in each hydraulic chamber 44, 45 is adjusted. In the tubular member 17,
Rotational torque according to the magnitude of the hydraulic pressure in each hydraulic chamber 44, 45 acts via each vane 80. Then, the tubular member 17 rotates relative to the cover 20 due to the rotational torque.

As a result, the valve opening / closing timing can be adjusted according to the operating state of the engine, as in the above-described embodiment. Furthermore, according to the above configuration, a member that moves in the axial direction of the camshaft 11 such as the piston gear 21 is not required, so that the valve timing control device in the coaxial direction can be shortened.

(2) In the above embodiment, the valve opening / closing timing of the intake valve is continuously changed by controlling the switching valve 23. However, the valve opening / closing timing can be changed continuously. It is not necessary, and for example, it may be selectively changed to have some valve opening / closing timing states.

(3) In the above embodiment, the valve opening / closing timing of the intake valve is changed by the VVT mechanism 12 provided on the intake side camshaft 11, but the VVT mechanism 12 is provided on the exhaust side camshaft. The valve opening / closing timing of the exhaust valve may be changed.
Further, a VVT mechanism may be provided on both the intake camshaft 11 and the exhaust camshaft to change the valve opening / closing timings of both the intake valve and the exhaust valve.

(4) In the above embodiment, when it is not necessary to change the valve opening / closing timing, the energization control for the drive motor 47 is stopped and the positional relationship between the valve element 18 and the cylindrical member 17 is changed to the "intermediate holding". Position,
The following configuration can also be adopted. That is, the positions where the supply and discharge oil grooves 68 and 69 of the valve body 18 and the advance side and retard side oil grooves 76 are formed are changed so that the drive motor 47 is energized as shown in FIG. When the rotational torque that is not controlled and acts on the valve body 18 is “0”, the valve body 18 and the tubular member 1 are
The positional relationship of 7 is set to the "retard control position". Then, the position of the valve element 18 may be sequentially switched from the “retard angle control position” to the “intermediate holding position” and the “advance angle control position” as the current value supplied to the stator coil 52 increases. .

In the case of such a configuration, it is not necessary to reverse the direction of the rotational torque applied from the drive motor 47 to the valve body 18 to the positive and negative directions, so that the energization control of the drive motor 47 is easy. It will be

While the embodiments embodying the present invention and other embodiments have been described above, technical ideas that can be understood from each embodiment will be described below. (A) In the valve timing control device for an internal combustion engine according to claim 1, the housing is connected to the cam shaft so as to be integrally rotatable, and the phase changing means is connected to the rotating body so as to be integrally rotatable. A cover, a movable member that is disposed between the cover and the housing, and meshes with at least one of the cover and the housing by helical teeth, and is formed on both sides of the movable member in the axial direction of the camshaft 11. A valve timing control device for an internal combustion engine, comprising:

According to the configuration described in (a) above, the switching valve is switched to change the pressure of the fluid in each pressure chamber,
The housing can be rotated relative to the cover by moving the movable member in the axial direction of the camshaft. As a result, the rotation phase of the camshaft that rotates integrally with the housing can be changed with respect to the rotating body, and the valve opening / closing timing can be changed.

[0084]

According to the present invention, in a valve timing control device for an internal combustion engine, it is possible to prevent deterioration of controllability due to axial vibration of the camshaft.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a tip portion of a camshaft, a VVT mechanism, and the like.

FIG. 2 is a partially enlarged sectional view of FIG.

FIG. 3 is a cross-sectional view showing a tip end portion of a camshaft, a VVT mechanism, and the like.

FIG. 4 is a sectional view showing a tip end portion of a camshaft, a VVT mechanism, and the like.

FIG. 5 is a sectional view taken along line VV of FIG. 1;

6 is a sectional view taken along line VI-VI in FIG.

7 is a sectional view taken along line VII-VII of FIG.

FIG. 8 is a diagram showing a relationship between a rotation torque acting on a valve body and a rotation angle of the valve body.

FIG. 9 is a cross-sectional view showing a cover, a tubular member, and the like according to another embodiment.

FIG. 10 is a diagram showing a relationship between a rotational torque acting on a valve body and a rotation angle of the valve body.

FIG. 11 is a cross-sectional view showing a conventional valve timing control device.

[Explanation of symbols]

11 ... Camshaft, 12 ... VVT mechanism (phase changing means), 15 ... Cylinder head (internal combustion engine), 17 ... Cylindrical member (housing), 18 ... Valve body, 19 ... Sprocket, 23 ... Switching valve, 44 ... Advance Angle side hydraulic chamber, 45 ... retard angle side hydraulic chamber, 47 ... drive motor (drive control means), 53 ... E
CU (drive control means), 56 ... Head oil passage, 58 ... Oil pump (pressurized fluid supply source), 61 ... Oil groove, 62 ... Oil groove, 63 ... Shaft oil passage, 64 ... Supply oil hole, 65 ... First oil supply passage, 66 ... Second oil supply passage, 67 ... Communication passage,
68 ... Supply oil groove, 69 ... Discharge oil groove, 70 ... Oil hole, 7
2 ... discharge oil hole, 73 ... drain hole, 74 ... advance side oil groove,
75 ... Advance side oil hole, 76 ... Retardation side oil groove, 77 ... Retardation side oil hole, 82 ... Advancement side oil groove, 83 ... Advancement side oil hole, 84 ... Retardation side oil groove, 85 ... Oil holes on the retard side (56, 61-77, 82-
85 forms a pressure passage).

Claims (1)

[Claims] 1. A cam shaft that is rotatably supported by an engine body and that opens and closes a valve, and a cam shaft that is provided on the cam shaft to transmit the rotational drive force of the engine and to transfer the rotational drive force to the cam shaft. A phase that has a rotating body for transmission and a pressure chamber to which a pressurized fluid is supplied, and changes the rotation phase of the camshaft by relatively rotating the camshaft and the rotating body by the pressure of the fluid in the pressure chamber. A changing means, a pressure passage for supplying a fluid from a pressurized fluid supply source to the pressure chamber and discharging the fluid from the pressure chamber, and a pressure passage provided in the middle of the pressure passage for removing the fluid in the pressure chamber. A valve timing control device for an internal combustion engine, comprising: a switching valve for adjusting pressure; and drive control means for driving and controlling the switching valve in accordance with an operating state of the internal combustion engine, The exchange valve has a housing and a valve body provided in the housing and rotatable about an axis parallel to the axis of the camshaft as a rotation axis. The drive control means allows the valve body to rotate relative to the housing. By changing the phase,
A valve timing control device for an internal combustion engine, characterized in that a flow state of a fluid in the pressure passage is switched.