JPH07139318A - Valve-timing adjusting device - Google Patents

Abstract

PURPOSE:To enhance on-vehicle mountability by arranging a spool control valve for controlling the position of a hydraulic piston for adjusting valve timing so as to be situated above a camshaft and to be perpendicular thereto for facilitating the machining of oil-pressure passages, and also by lengthening the seal length of the control valve. CONSTITUTION:When, for instance, a maximum current is supplied to the coil part 21 of a control valve 10 through a control circuit 9, a spool 24 is moved to one side in the inside of a sleeve 23. Then, respective openings 23a and 23c, and another respective openings 23d and 23b are communicated with each other, so that an oil-pressure supply passage 30 and an oil-pressure releasing passage 15b are communicated with an oil-pressure passage 1d and with another oil-pressure passage 1a respectively. Accordingly, oil is supplied to a spark- advance side oil-pressure chamber 14, while the oil inside a spark-delay side oil-pressure chamber 12 is discharged. As a result, a hydraulic piston 8 is moved to one side, and a camshaft 1 is relatively turned so as to be advanced with regard to a timing pulley 5. In this case, the control valve 10 is arranged so as to be situated above the camshaft 1 and so that its sleeve 23 is perpendicular to the camshaft 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve timing adjusting device for adjusting the opening timing of an intake valve or an exhaust valve of an internal combustion engine.

[0002]

2. Description of the Related Art A conventional valve timing adjusting device for an internal combustion engine is provided with a movable gear between a timing pulley and a cam shaft, and by moving between these gears, the timing pulley and the cam shaft are relatively rotated. Change the valve opening / closing timing. Further, hydraulic chambers are formed in front of and behind the gears, and hydraulic pressure supply means for supplying hydraulic pressure to the two hydraulic chambers via a cam journal portion is provided.

By adjusting the hydraulic pressure supplied to the two hydraulic chambers by the hydraulic pressure supply means, the gear is moved between the cam pulley and the cam shaft in a desired direction, or stopped and held at a desired position. It Thereby, the valve timing is adjusted to a desired timing according to the operating state.

[0004]

According to the conventional two hydraulically controlled valve timing devices as described above, three types and four passages having different roles are required from the spool type control valve. That is, a passage communicating with the advance chamber side hydraulic chamber that drives the gear toward the advance chamber, a passage communicating with the retard chamber hydraulic chamber that drives the gear toward the retard chamber, and a drain system of two systems. It is a passage that communicates.

When the control valve is mounted on the upper part of the cylinder head of the engine, the passage is arranged around the camshaft just below the control valve in consideration of downsizing of the control valve and improvement of mountability. Is difficult. Therefore, if the passage is formed obliquely, it is necessary to dispose the passage in the bearing portion and the opening portion of the camshaft so as to be displaced in the axial direction of the camshaft. In the valve timing adjusting device with hydraulic control on both sides, the number of hydraulic ports increases, and the number of man-hours for processing the housing becomes complicated.

The one disclosed in JP-A-4-109007 has a valve timing adjusting device mounted on a cam cap. If the control valve is arranged parallel to the cam shaft as shown in this publication, it is possible to solve the problem of shifting the port in the axial direction, but since it is located above the engine cylinder head cover from the mounting surface, the engine The total height is increased, which causes problems in mounting on vehicles.

The present invention has been made to solve the above problems, and it is an object of the present invention to provide a valve timing device having improved workability and mountability of a hydraulic passage.

[0008]

To achieve the above object, a valve timing adjusting device of the present invention is provided with a camshaft for driving at least one of an intake valve and an exhaust valve of an internal combustion engine, and the camshaft. Camshaft driving means provided at one end of the crankshaft for transmitting rotational force to the camshaft in synchronization with the crankshaft of the internal combustion engine, and meshed between the crankshaft side member and the camshaft side member At least one of the teeth provided on the circumference is a helical tooth, and a cylindrical gear that transmits the rotation of the crankshaft side member to the camshaft side member, and axially moves the gear by hydraulic pressure, An advance side hydraulic chamber for relatively rotating the cam shaft side member to the advance side with respect to the crank shaft side member, and a relative rotation of the cam shaft side member for the retard side with respect to the crank shaft side member The retard side hydraulic chamber Gear drive means having a plurality of openings, a sleeve having a plurality of openings, and a spool that selectively opens and closes the plurality of openings by sliding in the sleeve. When rotating relative to the member toward the advance side, oil is supplied to the advance side hydraulic chamber and oil is discharged from the retard side hydraulic chamber, and the camshaft side member is moved to the crankshaft side member. On the other hand, when relatively rotating to the retard side, while supplying oil to the retard side hydraulic chamber, draining oil from the advance side hydraulic chamber,
A control valve that supplies oil to both hydraulic chambers when the camshaft side member is held at a desired position with respect to the crankshaft side member, and the control valve is provided above the camshaft. It is arranged in a direction orthogonal to the cam shaft.

In the above structure, it is preferable that the control valve is arranged at a position where a part of the outer circumference of the sleeve overlaps the bearing portion of the cam shaft.

[0010]

According to the structure of the valve timing adjusting device of the present invention, the control valve is arranged so that the sleeve of the control valve is orthogonal to the upper part of the camshaft.
The hydraulic passage can be easily machined and formed, the control valve seal length can be secured long, and the mountability can be improved.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. An embodiment of a valve timing device to which the present invention is applied is shown in FIGS. A timing belt (not shown) that transmits the power of a crankshaft rotates a timing pulley 5 that is a crankshaft side member, and the camshaft 1 rotates in synchronization with this rotation. It should be noted that the timing pulley 5 and the cam shaft 1 rotate clockwise (hereinafter, this direction is referred to as an advance direction) when viewed from the direction of the arrow X in FIG.

A camshaft sleeve 4 which is a substantially cylindrical camshaft side member is fixed to the end of the camshaft 1 by a pin 3 and a bolt 2 so as to rotate integrally with the camshaft 1. An external tooth helical spline 4 a is formed on a part of the outer peripheral surface of the camshaft sleeve 4. Further, the timing pulley 5 is sandwiched between the camshaft 1 and the camshaft sleeve 4 so as to be restricted from moving in the axial direction and supported so as to be rotatable relative to the camshaft 1. Then, a stepped cylindrical sprocket sleeve 7 is fixed to the timing pulley 5 with bolts 6. A groove 6a is formed on the mounting surface of the sprocket sleeve 7 to the timing pulley 5, and the groove 6a
An O-ring 16 for keeping liquid tightness is provided inside.

The small diameter portion 7b of the sprocket sleeve 7 is
The camshaft sleeve 4 is opposed to the camshaft sleeve 4 in the radial direction with a predetermined gap. Then, the internal tooth helical splines 7a are formed on a part of the inner peripheral surface of the small diameter portion 7b. The internal tooth helical spline 7a corresponds to the external tooth helical spline 4a.
Is formed to have a twist angle in the opposite direction. Note that either the external tooth helical spline 4a or the internal tooth helical spline 7a may be a spline having a straight tooth parallel to the axial direction with a twist angle of zero.

Then, in the radial gap between the camshaft sleeve 4 and the small diameter portion 7b of the sprocket sleeve 7,
A hydraulic piston 8, which is a substantially cylindrical gear that is movable in the axial direction of the camshaft 1, is inserted. The hydraulic piston 8
Is composed of a cylindrical portion 8c and a disk portion 8d having a hole press-fitted into the end portion of the cylindrical portion 8c. Cylindrical part 8
The c is slidably fitted to the timing pulley 5. An inner tooth helical spline 8a that meshes with the outer tooth helical spline 4a of the camshaft sleeve 4 is formed on a part of the inner peripheral surface of the cylindrical portion 8c, and an inner tooth helical of the sprocket sleeve 7 is formed on a part of the outer surface. Spline 7
An external tooth helical spline 8b that meshes with a is formed. Due to the engagement of the splines with each other, the rotation of the timing pulley 5 passes through the sprocket sleeve 7, the hydraulic piston 8, the camshaft sleeve 4, and the camshaft 1
Be transmitted to. It is provided so as to be movable in the axial direction.

In this embodiment, the twist angle of the helical spline is set so that the valve timing changes to the retard side when the hydraulic piston 8 moves to the left in the figure. Further, a groove 8 is formed at the outer peripheral end of the disk portion 8d of the hydraulic piston 8 facing the inner peripheral surface of the sprocket sleeve 7.
e is formed, and a piston ring 11 for maintaining liquid tightness is provided in the groove 8e. With this hydraulic piston 8,
The internal space formed by the timing pulley 5 and the sprocket sleeve 7 is divided into two chambers. The hydraulic piston 8 has an advancing hydraulic chamber 14 on the left side and a retarding hydraulic chamber 12 on the right side.

A bolt 18 is attached to a hole formed at the left end of the sprocket sleeve 7 in the figure.
A groove 18a is formed in the bolt 18 and the groove 1
An O-ring 17 for maintaining liquid tightness is provided in 8a.
The bolt 2 attached to the camshaft 1 is formed with a hydraulic passage 2a that penetrates the bolt 2 in the axial direction and has one end open to the advance-side hydraulic chamber 14. The other end of the hydraulic passage 2a communicates with the hydraulic passage 1d formed at the axial center of the camshaft 1. As a result, the hydraulic passage 1d communicates with the advance-side hydraulic chamber 14 via the hydraulic passage 2a.

On the other hand, in the camshaft 1, another hydraulic passage 1a is formed in addition to the hydraulic passage 1d. The hydraulic passage 1a is connected to an annular groove 1b formed in the camshaft 1. Then, the annular groove 1b is provided in the timing pulley 5
Communicates with the hydraulic passage 5a formed in. This hydraulic passage 5
a opens to the retard angle side hydraulic chamber 12, whereby the hydraulic passage 1
The a communicates with the retard side hydraulic chamber 12 via the annular groove 1b and the hydraulic passage 5a.

The two hydraulic passages 1a and 1d formed in the camshaft 1 communicate with the control valve 10.
Further, the control valve 10 communicates with a hydraulic pressure supply passage 30 for supplying oil in the oil pan 29 that is pumped by the oil pump 13 and two hydraulic pressure release passages 15 a, 15 b for returning oil to the oil pan 29. Next, the configuration of the control valve 10 will be described.

A yoke 20 having a substantially cylindrical shape and made of a magnetic material.
Inside, a winding part 21 and a rod-shaped moving core 22 that can slide in the yoke 20 are provided. Also, the yoke 20
A cylindrical sleeve 23 is attached to the end of the.
The sleeve 23 has a plurality of openings 23a communicating with a plurality of passages through which the oil passes, at a predetermined wall surface position,
23b, 23c, 23d and 23e are formed.

Inside the sleeve 23, there is provided a spool 24 which can slide inside. This spool 24 is
Large-diameter portion 24 having substantially the same diameter as the inner diameter of the sleeve 23
a, 24b, 24c, 24d, and a small diameter portion connecting these large diameter portions. And the spool 24
One end contacts the moving core 22 and the other end contacts the compression coil spring 25 provided on the sleeve 23. As a result, the spool 24 and the moving core 22 are biased by the compression coil spring 25 to the left in the drawing.

The spool 24 moves in proportion to the current value supplied to the winding portion 21. Specifically, when current is supplied to the winding portion 21, the yoke 20 and the moving core 22 are
A suction force is generated in the void portion 28 between and. This moving force causes the moving core 22 and the spool 24 to move rightward in the figure against the biasing force of the compression coil spring 25, as shown in FIGS. 2 and 3. When the current supply to the winding portion 21 is cut off, the moving core 22 and the spool 24 are moved leftward by the urging force of the compression coil spring 25, and the state shown in FIG. 1 is restored.

The value of the current supplied to the winding part 21 is as shown in FIG.
Is zero and is set to a predetermined maximum value in FIG. The supply current value is controlled by the control circuit 9. The spool 24 and the sleeve 23 of the control valve 10 are in the state of FIG. 1 (that is, the supply current is zero).
At this time, the right end of the large diameter portion 24b of the spool 24 opens the opening 23b with a predetermined clearance A, while the right end of the large diameter portion 24c opens the opening 23c with a predetermined clearance B. To be done.

On the other hand, in the state of FIG. 2 (that is, the predetermined maximum value of the supply current), the left end of the large diameter portion 24b of the spool 24 opens the opening portion 23b with a predetermined clearance D, while the large diameter portion 24c of the large diameter portion 24c. The left end is set to open the opening 23c with a predetermined clearance C. The clearances C and D are set so that C> D. When the spool 24 moves in the sleeve 23, the large diameter portions 24a to 24d of the spool 24 cause the opening 2
3a-e are selectively communicated or closed. As a result, the communication state of the hydraulic passages 1a and 1d with the hydraulic supply passage 30 and the hydraulic release passages 15a and 15b is changed, and oil is supplied to or discharged from the advance side hydraulic chamber 14 and the retard side hydraulic chamber 12. To be done. Therefore, the hydraulic pressure acting on both sides of the hydraulic piston 8 changes, and the hydraulic piston 8 moves in the axial direction or is held at a predetermined position.

Next, the structure of the spool valve for hydraulically controlling the hydraulic piston 8 and the structure of the hydraulic passage will be described in detail. 4 is a view showing a spool valve mounted on the engine, and FIG. 5 is a sectional view taken along line VV shown in FIG. The spool 24 is formed with an axial hole 24f and a radial hole 24g. The axial hole 24f extends axially in the axial center of the spool 24, and one end of the axial hole 24f has a chamber 36 on the compression coil spring 25 side.
And the other end is closed. Radial hole 24g
Penetrates in the radial direction of the spool 24 and communicates with the chamber 26 on the solenoid side. A through hole 35a is formed in the central portion of the adjusting screw 35 fitted to the end portion of the sleeve 23.

The cam cap 50 is fixed to an engine cylinder head (not shown) with bolts, and also serves as an oil supply from the bearing of the cam shaft 1 and the control valve 10 to the valve timing adjusting mechanism 100. The cam cap 50 has an insertion hole 53 having substantially the same diameter as the outer diameter of the large diameter portion of the sleeve 23 of the control valve 10, and the control valve 10 inserted into the insertion hole 53 is attached to the bolt 60 by a mounting stay 61. It is fixed at. Further, the respective ports 23a, 23b, 23c, 23d, 23e of the control valve 10 have hydraulic passages 53a, 53b, 53 formed in the cam cap 50.
It is connected to c, 53d, and 53e.

The hydraulic passage 53a communicates with the oil pump 13 of the engine, the hydraulic passage 53b communicates with the hydraulic passage 1a of the camshaft 1, and the hydraulic passage 53c communicates with the hydraulic passage 1d of the camshaft 1. Hydraulic passages 53d, 53e
The exhaust port communicates with the inside of the engine cylinder head 51. A throttle 23f that connects the insertion hole 53 and the hydraulic passage 53e is formed on the outer peripheral portion of the distal end of the sleeve 23.

The engine head cover 200 is sealed with the arc portion 54 of the cam cap 50 via a seal member 201. The sleeve 23 of the control valve 10 is mounted above the cam cap 50 and in a direction perpendicular to the axis of the cam shaft 1. With this configuration, since the control valve 10 can be arranged between the timing pulley 5 and the engine head cover 200, the overall height of the engine is not much different from the conventional product.

The sleeve 23 of the control valve is arranged at a position where a part of the outer circumference of the sleeve overlaps the bearing portion 55. As a result, as shown in FIGS. 5 and 6, since the two hydraulic passages 53d and 53e as drain passages can be formed in a straight shape, it is possible to form them with a mold and shorten the discharge pipe length. As a result, oil can be discharged smoothly. The hydraulic passage 53c can also be formed in a straight shape in the same manner, and thus can be easily formed by a mold. Since the hydraulic passage 53b is the only oblique hole, the seal length 55a, 55b of the bearing 55 becomes short because the opening becomes elliptical when the inclination angle becomes large, but as in this embodiment. By arranging them, the inclination angle of the hydraulic passage 53b can be made small, so that the seal length can be sufficiently secured, so that the sealing performance is improved.

Next, the operation of this embodiment will be described. When the current is not supplied to the winding portion 21 by the control circuit 9,
The spool 24 moves inside the sleeve 23 to the position shown in FIG. Then, since the opening 23a communicates with the opening 23b and the opening 23c communicates with the opening 23e,
The hydraulic pressure supply passage 30 communicates with the hydraulic passage 1a, while the hydraulic release passage 15a communicates with the hydraulic passage 1d. Therefore,
While the oil is supplied to the retard side hydraulic chamber 12, the oil in the advance side hydraulic chamber 14 is discharged.

As a result, the hydraulic pressure in the retarding side hydraulic chamber 12 becomes higher than the hydraulic pressure in the advancing side hydraulic chamber 14, so that the hydraulic piston 8 moves leftward in the figure, and the camshaft 1 moves relative to the timing pulley 5. And the valve timing is changed to the retard side. In FIG. 1, the hydraulic piston 8 moves to the leftmost position in the figure due to the hydraulic pressure,
The state where the camshaft 1 is in the most retarded state is shown.

On the other hand, when the control circuit 9 supplies a predetermined maximum current to the winding portion 21, the spool 24 moves inside the sleeve 23 to the position shown in FIG. Then, the opening 2
Since 3a communicates with the opening 23c and the opening 23d communicates with the opening 23b, the hydraulic pressure supply passage 30 communicates with the hydraulic passage 1d, while the hydraulic release passage 15b communicates with the hydraulic passage 1a. Therefore, the oil is in the advance side hydraulic chamber 1
4, the oil in the retard side hydraulic chamber 12 is discharged.

As a result, the hydraulic pressure in the advance side hydraulic chamber 14 becomes higher than the hydraulic pressure in the retard side hydraulic chamber 12, so that the hydraulic piston 8 moves to the right in the figure and the camshaft 1 moves relative to the timing pulley 5. And the valve timing is changed to the advance side. In FIG. 2, the hydraulic piston 8 moves most to the right in the figure due to the hydraulic pressure,
The state where the camshaft 1 is in the most advanced state is shown.

Furthermore, when the winding portion 21 is supplied with a certain predetermined current by the control circuit 9, the spool 24
, The attraction force for attracting the moving core 22 and the biasing force of the compression coil spring 25 are balanced, and the inside of the sleeve 23 is held at a predetermined position (hereinafter, referred to as an intermediate position) shown in FIG. Then, the large-diameter portion 24b closes the opening 23b, and the large-diameter portion 24c closes the opening 23c, cutting off the supply and discharge of oil to the hydraulic chambers 12 and 14.
As a result, the hydraulic piston 8 is held at this position.

According to the present embodiment described above, the control valve 1
No. 0 supplies a predetermined amount of oil into the advance side hydraulic chamber 14 and fills the retard side hydraulic chamber 12 when the hydraulic pistons 8 and 14 are filled with oil to hold the hydraulic piston 8 at a desired position. Cut off the oil supply and discharge. Therefore, this
When the camshaft 1 is held at a desired position with respect to the crankshaft side member, the movement of the hydraulic piston in the advance side hydraulic chamber 14 direction due to the driving torque reaction force of the camshaft 1 can be reduced. Therefore, the hydraulic piston 8 can be stably held at a desired position, and the valve timing can be opened / closed at a desired timing.

[Brief description of drawings]

FIG. 1 is a sectional view of a valve timing adjusting device according to an embodiment of the present invention in a most retarded state.

FIG. 2 is a sectional view of the valve timing adjusting device according to the embodiment of the present invention in the most advanced state.

FIG. 3 is a cross-sectional view of the valve timing adjusting device according to the embodiment of the present invention when the intermediate holding is performed.

FIG. 4 is a cross-sectional view of the valve timing adjusting device according to the embodiment of the present invention.

5 is a cross-sectional view taken along line VV shown in FIG.

FIG. 6 is a bottom view of the cam cap according to the embodiment of this invention.

[Explanation of symbols]

 1 camshaft (camshaft) 4 camshaft sleeve 5 timing pulley (camshaft driving means) 7 sprocket sleeve 8 hydraulic piston 9 control circuit 10 control valve 12 retard side hydraulic chamber 14 advance side hydraulic chamber 23 sleeves 23a, 23b, 23c, 23d, 23e Opening 24 Spool 53a, 53b, 53c, 53d, 53e Hydraulic passage 55 Bearing part

Claims (2)

[Claims] 1. A camshaft for driving at least one valve of an intake valve and an exhaust valve of an internal combustion engine, and a camshaft provided at one end of the camshaft and rotating in synchronization with a crankshaft of the internal combustion engine. The camshaft driving means for transmitting the force to the camshaft, and at least one of the teeth provided on the inner and outer circumferences meshed between the crankshaft side member and the camshaft side member is a helical tooth, A cylindrical gear that transmits the rotation of the shaft side member to the cam shaft side member, and an axial movement of the gear by hydraulic pressure to relatively rotate the cam shaft side member to the advance side with respect to the crank shaft side member. Gear drive means having an advancing side hydraulic chamber for moving and a retarding side hydraulic chamber for relatively rotating the camshaft side member to the retarding side with respect to the crankshaft side member, and a plurality of openings The sleeve and the inside of this sleeve The advance angle side hydraulic chamber when the camshaft side member is relatively rotated in the advance side with respect to the crankshaft side member by moving the spool to selectively open and close the plurality of openings. Oil to the retard angle side hydraulic chamber and oil is discharged from the retard angle side hydraulic chamber to rotate the camshaft side member relative to the crankshaft side member in the retard angle side. And discharging the oil from the advance side hydraulic chamber and holding the camshaft side member at a desired position with respect to the crankshaft side member, supplying the both hydraulic chambers with oil so as to fill the oil. A valve, and the control valve is disposed on an upper portion of the cam shaft in a direction orthogonal to the cam shaft. 2. The valve timing device according to claim 1, wherein the control valve is arranged at a position where a part of the outer circumference of the sleeve overlaps the bearing portion of the cam shaft.