JPH07217412A - Valve timing control device for internal combustion engine - Google Patents

Abstract

PURPOSE:To improve valve timing control responsiveness by increasing a sectional area of a passage while simplifying the supply passage structure. CONSTITUTION:A cylindrical gear 5 arranged between a cam shaft 1 and a timing pulley 4 is axially moved, while a relative rotational phase between the shaft 1 are the pulley 4 is converted. A supply passage of a driving means which moves the cylindrical gear 5 is directly communicated with a hydraulic chamber 22. A servo mechanism 24 which controls a moving position of the cylindrical gear 5 is arranged on a discharge passage 27 introduced from the hydraulic chamber 22 into a rocker cover 16 according to a moving position of a spool valve 33.

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 variably controlling the opening / closing timing of an intake valve or an exhaust valve of an internal combustion engine according to the operating condition.

[0002]

2. Description of the Related Art Various conventional valve timing control devices for internal combustion engines have been provided, and one of them is known, for example, as disclosed in Japanese Patent Application Laid-Open No. 1-134011.

In brief, a cylindrical sleeve axially connected to one end of a camshaft via a bolt and a ball bearing are arranged on the outer circumference of the sleeve so as to be rotatable relative to each other. A timing pulley that is rotationally driven by a crank shaft of
The piston is interposed between the sleeve and the timing pulley and is movable in the axial direction. This piston is adapted to move forward by the hydraulic pressure in the hydraulic chamber provided on one end side. Further, between the piston, the timing pulley and the sleeve, there is provided a phase conversion means for converting the relative rotational phase of the sleeve and the timing pulley as the piston moves in the axial direction.

A movable member that interlocks with the piston is slidably provided in the sleeve between the hydraulic chamber and the hydraulic supply passage and the hydraulic release passage, and slides on the movable member. A spool that is freely fitted and is relatively movable in the axial direction is provided, and the movable member and the spool form a servo valve. The movable member and the piston are biased forward by the spring force of the coil spring.

Further, the servo valve is adapted to connect or disconnect the hydraulic chamber and the hydraulic supply passage or the hydraulic release passage by the movement of the spool in the axial direction. The spool is adapted to move in the axial direction by an electric actuator.

When the electromagnetic actuator operates in response to a change in the engine operating state and the hydraulic supply passage communicates with the hydraulic chamber as the spool moves in one direction, the piston resists the spring force of the coil spring and moves backward. Move to. As a result, the phase conversion means converts the relative rotational phase of the cam shaft and the timing pulley into one side.

On the other hand, as the spool moves in the other direction, the hydraulic chamber, the hydraulic supply passage, and the hydraulic release passage communicate with each other, the piston and the movable member move to a predetermined position in front, and the camshaft and the timing pulley are connected. The relative rotation phase is continuously converted.

[0008]

However, in the above-mentioned conventional device, since the servo valve is arranged in the middle of the hydraulic pressure supply passage, the structure of the hydraulic pressure supply passage becomes complicated, and
The size of the passage cross-sectional area is restricted. That is, since a part of the hydraulic pressure supply passage is formed on the outer periphery of the spool, a supply passage portion communicating with the outer peripheral groove of the spool is formed on one end side inside the peripheral wall of the sleeve, while the outer peripheral groove of the spool is formed on the lower inner end side of the sleeve. It is necessary to form a supply passage portion that communicates with the hydraulic chamber. Therefore, the structure of the entire hydraulic pressure supply passage becomes complicated, and a part of the hydraulic pressure supply passage must be formed in the axial direction within the sleeve peripheral wall in a small space. It gets smaller. As a result, the flow resistance of the hydraulic oil flowing through the hydraulic pressure supply passage increases, and the supply speed into the hydraulic pressure chamber decreases. For this reason, the movement responsiveness of the piston is lowered, and eventually the relative rotation conversion speed of the camshaft and the timing pulley may be lowered.

Further, as the passage structure of the oil supply passage becomes complicated, it is inevitable that the manufacturing work efficiency and the cost increase.

[0010]

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 rotating body which is rotationally driven by an engine, and is transmitted from the rotating body. Is interposed between a cam shaft having a cam that operates an intake / exhaust valve by a rotating force, and the rotating body and the cam shaft, and converts the relative rotational phase of the both as the cam shaft moves in the axial direction. In a valve timing control device comprising a phase conversion means and a drive means for controlling the movement of the phase conversion means via a hydraulic circuit, a supply passage of the hydraulic circuit is formed at one end side of the phase conversion means. Servo mechanism for controlling the moving position of the phase conversion means by controlling the discharge amount of the hydraulic fluid in a discharge passage for directing the hydraulic fluid discharged from the hydraulic chamber to the outside while directly communicating with the hydraulic chamber. It is characterized by having It is.

The invention of claim 2 is characterized in that a flow rate control valve for controlling the flow rate of the hydraulic fluid in the supply passage according to the operation of the servo mechanism is provided in the upstream portion of the supply passage.

[0012]

According to the invention of claim 1, since the servo mechanism is provided not on the hydraulic pressure supply passage side but on the discharge passage side and the hydraulic pressure supply passage is directly communicated with the hydraulic chamber, the structure of the entire supply passage is simplified. To be done. Therefore, it becomes possible to set the passage sectional area of the supply passage as large as possible.

Further, according to the second aspect of the invention, since the flow control valve narrows the flow passage in the upstream portion of the supply passage when the supply passage is in communication with the hydraulic chamber and the discharge passage by the servo mechanism, Supply of hydraulic fluid to the hydraulic chamber is suppressed. As a result, it is possible to prevent the occurrence of pressure drop in the hydraulic path for each sliding portion of the engine.

[0014]

1 shows an embodiment in which the valve timing control device of the present invention is applied to the intake valve side.

That is, in FIG. 1, reference numeral 1 denotes a cam shaft in which a sleeve 2 is fixed to one end portion 1a of a main body from an axial direction by a mounting bolt 3, and 4 is rotatably provided on the outer periphery of the sleeve 2 and is attached to the cam shaft 1. Timing pulleys 5 serving as rotating bodies that transmit rotational force are tubular gears that are provided between the sleeve 2 and the timing pulley 4 so as to be movable in the axial direction of the camshaft and serve as phase conversion means.

The camshaft 1 has a cylinder head 6
Is rotatably supported by a cam bearing 7 provided at the upper end of the, and a cam (not shown) for integrally opening the intake valve against the spring force of the valve spring is provided at a predetermined position on the outer circumference. There is. Further, the sleeve 2 is formed to extend in the axial direction, and has one end portion 1a of the camshaft body at one end side.
A thin-walled tubular fitting portion 2a that fits from the outside is integrally provided, and a partition wall 2b is integrally provided on the bottom side of the fitting portion 2a. Also, on the outer circumference of the sleeve 2,
Outer teeth 2c having a helical shape are formed. Further, the mounting bolt 3 is screwed through the central hole 2d of the partition wall 2b and the bolt hole 1b formed in the axial direction of the camshaft body.

The timing pulley 4 has a cylindrical body 8
A gear portion 9 integrally provided at the center of the outer periphery of the tubular body 8 and having a timing belt wound around the outer periphery thereof, and first and first caulkedly fixed to the inner periphery of the front and rear ends of the tubular body 8. The cylindrical main body 8 is provided with two flanges 10 and 11, and inner teeth 8a having a helical tooth shape are formed on the inner circumference of the rear end side.

Further, the first and second flanges 10 and 11
Of the fixed base portions 10a and 11a are slidably supported on the outer peripheral surface of the sleeve 2, and the entire timing pulley 4 is supported on the sleeve 2 at two front and rear points around the gear portion 9. A disk-shaped front cover 12 is liquid-tightly fixed to a front end portion of the first flange portion 10 via a C ring 13 and a seal ring 14, and an interlocking portion described later is provided on an inner peripheral side of the fixed base portion 10a. A plurality of shaft insertion holes 10b through which the shaft 36 is inserted are formed at equidistant positions in the circumferential direction. Further, a drain hole 15 is axially formed through the outer peripheral side of the one shaft insertion hole 10b. The cylindrical portion 11 provided on the inner peripheral side of the second flange 11
A seal member 17 for sealing the inside of the rocker cover 16 is provided between b and the flange portion of the rocker cover 16. .

The cylindrical gear 5 has an annular groove 18 on the inner and outer circumferences.
A and 18b are formed, and inner and outer teeth 5a and 5b in the form of a helical tooth that mesh with the inner teeth 8a and the outer teeth 2c are formed on the inner and outer circumferences of the rear end portion. Also, the front end is
The inner and outer peripheral surfaces are slidably guided to the inner surface of the cylindrical main body 8 and the outer surface of the sleeve 2, and the hydraulic chamber 2 to be described later is inserted in the annular groove of the inner and outer peripheral surfaces.
Seal rings 19 and 20 for sealing 2 are fitted and fixed. Further, the tubular gear 5 is adapted to move in the axial direction by the driving means.

The driving means is elastically mounted between the inner end surface of the first flange 10 and the inner bottom surface of the tubular gear 5 to urge the tubular gear 5 in the rearward direction, and the tubular shape. A hydraulic chamber 22 formed between the annular grooves 18a and 18b on the inner and outer circumferences of the gear 5 and the tubular main body 8 and the sleeve 2, a hydraulic circuit 23 for supplying and discharging hydraulic pressure to and from the hydraulic chamber 22, and the inside of the hydraulic chamber 22. And a servo mechanism 24 for controlling the moving position of the cylindrical gear 5 by controlling the discharge amount of the hydraulic oil.

The hydraulic circuit 23 discharges the hydraulic oil in the hydraulic chamber 22 into the rocker cover 16 and a supply passage 26 having an upstream end connected to a main gallery 25 for supplying lubricating oil to each sliding portion of the engine. And a discharge passage 27 for discharging.

The supply passage 26 has a main gallery 25.
The lubricating oil in the oil pan 29 is introduced through the strainer 30 by the oil pump 28 provided on the upstream side, and the downstream end is directly connected to the hydraulic chamber 22. That is, the supply passage 26 is formed between the oil passage portion 26a formed inside the cylinder head 6 and along the radial direction of the camshaft 1, the central hole 2d, the bolt insertion hole 1b and the outer peripheral surface of the mounting bolt 3. And an annular passage portion 26b formed at the one end and communicating with the oil passage 26a.
And the sleeve 2 is formed so as to extend obliquely along the lower end of the rear end of the sleeve 2 along the substantially radial direction, one end of which is in the annular passage portion 26b and the other end of which is the rear end of the cylindrical gear 5 and the hydraulic chamber 22. And an inclined passage portion 26c that communicates with each other.

On the other hand, the discharge passage 27 has a discharge hole 27a which is formed at a substantially central position of the peripheral wall of the sleeve 2 in a substantially radial direction, a movable cylinder 32 of the servo mechanism 24, which will be described later, and a spool valve 33. And a through hole 27c, which are respectively formed in the radial direction of the sleeve 2 and communicate with the drain chamber 27d inside the sleeve 2, and are formed in an inclined shape at the upper end side of the rear end portion of the sleeve 2 to form the cylindrical shape. It is composed of a communication passage 27f that connects the inside of the rocker cover 16 and the drain chamber 27d via a drain groove 27e formed along the axial direction on the inner periphery of the portion 11b. The communication hole 27b has a guide groove 27g formed in the axial direction on the outer end side, while a groove groove 27h is formed on the outer end side of the through hole 27c. Further, an oil groove 27 is provided around the front end of the spool valve 33 for collecting the working oil flowing into the working chamber 31 inside the first flange 10 through the groove groove 27h into the drain chamber 27d.
i is formed.

The servo mechanism 24 is provided on the inner periphery of the sleeve 2 so as to be slidable in the axial direction, and on the inner periphery of the movable barrel 32 so as to be slidable in the axial direction. A spool valve 33, an electromagnetic actuator 34 that is fixed to the belt cover 57 and presses the spool valve 33 to the right in the figure, and a controller 35 that controls the operation amount of the electromagnetic actuator 34 according to the engine operating state. I have it.

The movable cylindrical body 32 is integrally provided with a flange portion 32a at a front end portion protruding from the tip end of the sleeve 2, and an outer peripheral portion of the flange portion 32a is formed larger than the outer diameter of the sleeve 2. . Further, the shaft insertion hole 10b is slidably inserted between the inner end surface of the outer peripheral portion of the flange portion 32a and the front end portion of the tubular gear 5 so that the tubular gear 5 moves forward as the tubular gear 5 moves. A plurality of interlocking shafts 36 that synchronously move the movable tubular body 32 are interposed. In addition, this movable cylinder 32
Is urged to the rearward moving position by the spring force of the coil spring 37 elastically mounted between the inner peripheral portion and the front cover 12, and the flange portion 32 a is always connected to the front end portion of the tubular gear 5 via the interlocking shaft 36. It comes into contact with.

The spool valve 33 has a cylindrical shape with a bottom,
The spring force of a coil spring 38 elastically mounted between the inner surface of the bottom wall and the head of the mounting bolt 3 urges it to the front position (in the left direction in the drawing), and the outer surface of the bottom wall has a sliding shaft. One end of 39 is in contact with from the axial direction. The sliding shaft 39 slidably penetrates through the center hole of the front cover 12 via a seal ring 40, and has the other end at the electromagnetic actuator 3
The drive shaft 41 of No. 4 is in contact from the axial direction.

The electromagnetic actuator 34 includes an electromagnetic coil 43 in a cylindrical body 42, a fixed core 44 that is excited by energization of the electromagnetic coil 43, and the fixed core 4.
The movable core 45 and the like to be sucked by 4 are stored. The movable core 45 has a drive rod 41 fixed to the front end thereof and is urged rightward in the figure by a spring member 46 elastically mounted on the rear end side, so that the front end edge of the drive rod 41 slides along the slide shaft 39. Is always in contact with the other end of the.

The controller 35 detects a current engine operating state based on an information signal output from a built-in microcomputer such as a crank angle sensor, an air flow meter, a water temperature sensor, and a throttle valve switch. Then, a control current is output to the electromagnetic coil 43 of the actuator 34 according to the operating state.

Further, a flow rate control valve 47 for controlling the flow rate of the hydraulic oil in the supply passage 26 in accordance with the operation of the servo mechanism 24 is provided at the connecting portion between the supply passage 26 and the main gallery 25.
Is provided.

That is, the flow control valve 47 has a valve hole 48 formed at the side of the cylinder head 6 so as to cross the connecting portion of the passages 25 and 26, and the valve hole 4 is provided.
A tubular valve 49 is slidably accommodated in the inside 8. A pilot passage 50 for transmitting pilot pressure in the supply passage 26 is connected to the bottom of the valve hole 48. The tubular valve 49 has a pressure receiving surface 4 that receives the pilot pressure at its tip.
9a, an annular passage groove 51 having a cross-sectional area equal to the cross-sectional areas of the passages 25 and 26 is formed on the outer circumference on the tip end side, and the passage groove 51 is provided at a substantially central position in the axial direction on the outer circumference. Annular orifice groove 5 with a cross-sectional area much smaller than
2 is formed. In addition, the tubular valve 49 has a valve hole 4
The spring force of the return spring 54 mounted between the bottom of the spring retainer 53 and the bottom of the spring retainer 53 fixed near the opening edge of the No. 8 front position, that is, both passages 25 and 26 and the orifice groove 5
It is urged to a position where the two communicate.

Incidentally, reference numeral 55 in the figure denotes a pressure adjusting valve provided in a relief passage 56 branched from the main gallery 25.

The operation of this embodiment will be described below.

First, in the engine low load range, the controller 3
5, the maximum control current is output to the electromagnetic actuator 34, the drive rod 41 advances as shown in FIG. 1, and the sliding shaft 39 is pushed into the working chamber 31. Therefore, the spool valve 33 moves backward against the spring force of the coil spring 38 to the right end side stopper 32b as shown in the drawing. Therefore, the hydraulic chamber 22 and the through hole 27c communicate with the discharge hole 27a through the communication hole 27b and the groove groove 27h in the maximum passage sectional area. Therefore, the hydraulic oil pressure-fed from the oil pump 28 to the main gallery 25 passes through the flow rate control valve 47 and the oil passage portion 26 a, the annular passage portion 26 b, and the inclined passage 26.
It is directly supplied into the hydraulic chamber 22 from c and then flows into the drain chamber 27d through the discharge hole 27a, the communication hole 27b and the communication hole 27c. Further, from there, it is discharged onto the cylinder head 6 in the rocker cover 16 through the communication passage 27f and the drain groove 27e.

Therefore, the tubular gear 5 is held at the maximum rear position shown in FIG. 1 by the spring force of the compression spring 21 as the hydraulic chamber 22 is lowered in pressure, and the relative rotational phase of the cam shaft 1 and the timing pulley 4 is changed. Convert to one side. As a result, the closing timing of the intake valve is controlled to the retard side, and as a result, combustion efficiency is improved and fuel economy and exhaust emission are improved.

Here, the movable tubular body 32 moves in the same direction and the same stroke amount as the tubular gear 5 moves backward, and maintains the communication state between the communication passage 27b and the groove groove 27h.

At this point, the hydraulic pressure in the supply passage 26 drops, so that the pressure from the pilot passage 50 to the pressure receiving surface 49 is reduced.
The pressure acting on a is reduced and therefore the tubular valve 49
Moves to the left position by the spring force of the return spring 54 as shown. Therefore, the hydraulic oil flowing from the main gallery 25 into the supply passage 26 is throttled by the orifice groove 52, and the amount of inflow into the entire hydraulic circuit 23 is greatly reduced. As a result, it is possible to prevent a decrease in lubrication performance due to an increase in the supply amount to each sliding portion of the engine.

On the other hand, when the load is changed from the low load region to the high load region, the electromagnetic actuator 34 is de-energized, so that the spool valve 33 is moved to the maximum leftward position by the spring force of the coil spring 38 as shown in FIG. Then, the outer peripheral surface closes the open end of the communication hole 27b. Therefore, the hydraulic oil flowing into the hydraulic chamber 22 from the supply passage 26 is stored in the hydraulic chamber 22 and the internal pressures of the supply passage 26 and the hydraulic chamber 22 rise. Accordingly, the tubular gear 5 moves to the maximum forward position against the spring force of the compression spring 21 as shown in the drawing, and converts the relative rotational phase of the cam shaft 1 and the timing pulley 4 to the other side. As a result, the closing timing of the intake valve is advanced, and as a result, the output can be improved.

Here, the movable cylindrical body 32 moves in the same direction as the cylindrical gear 5 with the same stroke amount through the interlocking shaft 36 with the forward movement of the cylindrical gear 5, but the communication passage 27
The open end of b does not communicate with the groove groove 27h and the closed state is maintained. .

At this point, as the internal pressure of the supply passage 26 rises, the pilot valve causes the cylindrical valve 49 to move to the right against the spring force of the return spring 54 as shown in the drawing, so that both passages 25, 26 are moved. Is communicated with each other via the passage groove 51, so that the hydraulic oil can be quickly and sufficiently supplied to the hydraulic chamber 22. Therefore, the rate of increase in the internal pressure of the hydraulic chamber 22 is increased, and the relative rotational phase conversion response of both 25 and 26 is improved. In this state, the hydraulic oil is not discharged from the discharge passage 27, so that the lubricating performance is not affected.

Further, when the low / high load range or the high load range is shifted to the middle load range, a predetermined control current is output to the electromagnetic actuator 34 to move the spool valve 33 to the front / rear intermediate position. Groove groove 2 as shown in 3
7h and a part of the opening end of the communication hole 27b relatively overlap each other, and the passage cross-sectional area is controlled to be small. Therefore, the hydraulic oil in the hydraulic chamber 22 passes through the discharge hole 27a and the first groove groove 27g, the communication hole 27b having a small passage sectional area, and is discharged through the groove groove 27h, the communication hole 27c and the like. For this reason, the internal pressure of the hydraulic chamber 22 is slightly reduced, so that the tubular gear 5 is held at an arbitrary intermediate position as shown in the drawing. As a result, the camshaft 1 and the timing pulley 4 are converted to a predetermined intermediate relative rotation position, and the closing timing of the intake valve is controlled to the retard side slightly. In addition, the movable cylindrical body 32
Also moves in the same direction as the cylindrical gear 5 with the same stroke amount, but the discharge hole 27a and the communication hole 27b secure a steady maximum passage sectional area by the guide groove 27g.

On the other hand, at this time, since the internal pressures of the hydraulic chamber 22 and the supply passage 26 are slightly lowered, the cylindrical valve 49 is moved to the leftward position by the spring force of the return spring 54 as shown in the figure, and is operated. The oil flow rate is restricted. Therefore, it is possible to prevent deterioration of the lubrication performance of each sliding portion.

Further, in this embodiment, as described above, since the entire structure of the supply passage 26 is simplified, it is possible to set the passage sectional area of each passage portion of the supply passage 26 to be sufficiently large. Become. Therefore, the flow resistance of the hydraulic oil decreases, the flow rate of the hydraulic oil supplied to the hydraulic chamber 22 per unit time increases, and the rising speed of the internal pressure increases.

Further, since the timing pulley 4 is supported by the flanges 10 and 11 at two points with respect to the sleeve 2, the front and rear tilting is prevented. Therefore, an unbalanced load on the tubular gear 5 is prevented.

Further, as described above, since the moving position of the cylindrical gear 5 can be set steplessly according to the moving position of the spool valve 33, highly accurate valve timing control according to the engine operating condition becomes possible. .

[0045]

As is apparent from the above description, claim 1
According to the invention, since the entire structure of the supply passage is simplified, the passage sectional area of the supply passage can be set sufficiently large. Therefore, the flow resistance of the hydraulic fluid is reduced, and the supply amount per unit time to the hydraulic chamber is increased. As a result,
The moving speed of the phase conversion means is improved, and the control response of valve timing is improved.

Further, the simplification of the structure of the entire supply passage makes it possible to improve the manufacturing work efficiency and reduce the cost.

According to the second aspect of the present invention, since the flow rate of the hydraulic fluid supplied to the hydraulic chamber can be appropriately controlled by the flow rate control valve, it is possible to prevent deterioration of the lubrication performance and the like for each sliding portion of the engine. .

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of the present invention.

FIG. 2 is a vertical sectional view showing the operation of this embodiment.

FIG. 3 is a vertical sectional view showing a different action of the present embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Camshaft 4 ... Timing pulley (rotating body) 5 ... Cylindrical gear (phase conversion means) 22 ... Hydraulic chamber 23 ... Hydraulic circuit 24 ... Servo mechanism 26 ... Supply passage 27 ... Discharge passage 47 ... Flow control valve

Claims (2)

[Claims] 1. A rotary body that is rotationally driven by an engine, a cam shaft having a cam that operates an intake / exhaust valve by the rotational force transmitted from the rotary body, and a rotary body that is interposed between the rotary body and the cam shaft. And a valve timing control device provided with a phase conversion means for converting the relative rotational phase of the two in accordance with the movement in the camshaft axial direction and a drive means for controlling the movement of the phase conversion means via a hydraulic circuit. In the above, the supply passage of the hydraulic circuit is directly connected to the hydraulic chamber formed at one end of the phase conversion means, and the discharge passage for guiding the hydraulic fluid discharged from the hydraulic chamber to the outside is operated. A valve timing control device for an internal combustion engine, comprising a servo mechanism for controlling a liquid discharge amount to control a moving position of the phase conversion means. 2. The internal combustion engine according to claim 1, wherein a flow rate control valve for controlling the flow rate of the hydraulic fluid in the supply passage according to the operation of the servo mechanism is provided in the upstream portion of the supply passage. Valve timing control device.