JP2926625B2 - Valve timing control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Purpose of the Invention] (Industrial application field) The present invention relates to a valve timing control device,
The valve timing of the engine is controlled linearly with respect to various conditions of the engine.

(Prior Art) As a prior art related to the present invention, for example, Japanese Patent Application Laid-Open
There is one disclosed in Japanese Patent No. 3111.

This conventional valve opening / closing timing control device 80 will be described with reference to FIG. 2. An inner and outer peripheral portion is provided between a timing pulley 81 having a helical spline formed on the inner periphery and a transmission member 82 having a helical spline formed on the outer periphery. Ring-shaped piston means 83 each having a helical spline formed at its portion are engaged. A timing belt 86 is engaged with the outer peripheral surface of the timing pulley 81, and is driven by a crankshaft (not shown) of an engine (not shown).

Here, the transmission member 82 is bolted to the camshaft 85
, So that they do not rotate relative to each other.

Further, the piston means 83 is divided into two in the axial direction, and a spring 86 is inserted between the two, thereby achieving a so-called scissors gear. This allows the timing pulley
When the rotational torque is transmitted to the 81 piston means 83 transmission member 82 and the transmission torque, the meshing noise generated by the backlash between the helical splines can be reduced.

Further, the pressure receiving plate 87 disposed on the right side of the piston means 83 in the figure moves together with the piston means 83, and moves the piston means 83 right and left in the figure according to the oil pressure of the hydraulic line 88.

Here, a spring 90 is disposed in the illustrated right space 89 of the piston means 83, and urges the piston means 83 to an initial position (the leftmost position in the figure).

(Problems to be Solved by the Invention) However, in the above-described conventional valve timing control device 80, the hydraulic pressure supplied to the hydraulic line 88 is only ON / OFF controlled by a hydraulic control valve (not shown). In addition, there are only two valve opening and closing times.

However, in recent years, higher performance of engines has been required,
The valve opening / closing timing should always be kept at an optimal timing.

Accordingly, it is a technical object of the present invention to provide a valve opening / closing timing control device that can set the valve opening / closing timing to an arbitrary timing.

[Configuration of the invention]

(Means for Solving the Problems) The technical means of the present invention taken to solve the above-mentioned technical means of the present invention is to use the valve opening / closing timing control device to detect the rotational position of a camshaft of an engine. A first sensor, a second sensor for detecting a rotational position of a crankshaft of the engine, a first hydraulic pump driven by the crankshaft to pump oil for lubrication to various parts of the engine, and a crankshaft. A second hydraulic pump that is driven to increase the discharge hydraulic pressure of the first hydraulic pump, a rotation phase change unit that is disposed on the camshaft and that changes a rotation phase of the camshaft with respect to a rotation phase of the crankshaft; (2) a hydraulic line connecting the discharge side of the hydraulic pump and the rotation phase changing means, and a hydraulic control device provided on the hydraulic line. A step, a drain line connecting a portion of the hydraulic line between the hydraulic control means and the rotation phase changing means and an oil pan of the engine via the hydraulic control means, and controlling the hydraulic control means An electronic control unit, wherein the electronic control unit receives at least output signals of the first and second sensors, linearly controls the rotation phase changing unit by the hydraulic control unit, and controls the rotation of the camshaft. When the rotation phase is maintained, the hydraulic pressure control means cuts off the hydraulic pressure line and the discharge line, and feedback-controls the hydraulic pressure at a portion of the hydraulic pressure line between the hydraulic pressure control means and the rotation phase changing means. It was done.

(Operation) According to the above-described technical means of the present invention, the rotation phase changing means is linearly controlled instead of ON / OFF control as in the related art, so that the valve opening / closing timing is always set to an optimal timing. Is done.

In addition, since the discharge pressure of the second hydraulic pump acts on the rotation phase changing means, even when the engine speed is low and the discharge pressure of the first hydraulic pump, which is the main pump, is low, the hydraulic pressure is again applied by the second hydraulic pump. , The high-pressure oil can be constantly supplied to the rotation phase changing means, and the operation thereof is not adversely affected by the engine speed.

(Example) Hereinafter, an example that embodies the technical means of the present invention will be described with reference to the accompanying drawings.

The valve opening / closing timing control device 10 is provided in the engine 11, and almost all operations thereof are controlled by the electronic control device 12. Engine 11 is crankshaft
13 and a cam shaft 14 driven by transmission means (for example, a belt member such as a V-belt or a cogged belt, a gear member, etc.) by the crank shaft 13, and the rotational positions of the shafts 13 and 14 are respectively set. It is detected by a crank position sensor (second sensor) 15 and a cam position sensor (first sensor) 16.

Here, in addition to the output signals of the crank position sensor (second sensor) 15 and the cam position sensor (first sensor) 16, the electronic control unit 12 also includes, for example, an engine oil temperature signal, an engine load signal, and an engine speed signal. Etc. are entered.

Oil for lubricating the engine 11 is always stored in an oil pan 17 provided at a lower portion of the engine 11 main body. When the engine 11 is operating, the oil is supplied by a first hydraulic pump 18 driven by a crankshaft 13. It is pressure-fed to various parts of the engine 11 via a hydraulic circuit 19. The hydraulic circuit 19 is provided with an oil filter 20, a relief valve 21, and the like.

Similarly, a second hydraulic pump 22 driven by the crank shaft 13 sucks oil from the hydraulic circuit 19 and discharges the oil to the hydraulic control means 23. The hydraulic control means 23 includes a first hydraulic control valve 24 and a second hydraulic control valve 25, and is duty-controlled by the electronic control unit 12. The first port 24a of the first hydraulic control valve 24 has a discharge line (hydraulic line) 26 of the second hydraulic pump 22; the second port 24b has an operating line (hydraulic line) 28 connected to the rotation phase changing means 27;
The port 24c communicates with the first port 25a of the second hydraulic control valve 25, and the second port 25b of the second hydraulic control valve 25 communicates with the oil pan 17 via a discharge line. Also, the discharge line 26
Is provided with a relief valve 29.

The rotation phase changing means 27 is provided at one end of the camshaft 14 and converts the rotation torque of the crankshaft 13 to the camshaft 14.
And the rotational phase of the camshaft 14 is changed. An intake / exhaust valve (not shown) is engaged with the camshaft 14, and the intake / exhaust valve opens and closes the intake / exhaust passage as the camshaft 14 rotates.

The timing pulley 30 is inserted into the camshaft 14 so as to be relatively rotatable, and the transmission means described above is engaged with the outermost peripheral surface 30a. Also, the inner peripheral surface of the timing pulley 30
A helical spline 30c is formed on the inner peripheral surface of a ring-shaped piston (piston means) 31 so as to mesh with the helical spline 30c.
a is formed.

Further, a helical spline 31b is formed on the outer peripheral surface of the ring-shaped piston 31, and a helical spline 32a is formed on the inner peripheral surface of the transmission member 32 so as to mesh with the helical spline 31b.

Further, the transmission member 32 is fixed to the camshaft 14 via a cover 34 integrally fixed by a bolt 35 and a pin 44 so as to be relatively non-rotatable.

Accordingly, the ring-shaped piston 31 is provided in a space 33 formed between the timing pulley 30 and the transmission member 32 which are spaced apart from each other.
The inside of the helical spline 30c ・ 31a ・
It can slide along 31b and 32a.

Here, a spring (spring means) 36 is disposed on the right side of the ring-shaped piston 31 in the space 33 in the drawing, and moves the ring-shaped piston 31 to an initial position (a position where the left end of the ring-shaped piston 31 is in contact with the cover 34). It is energizing.

A hydraulic chamber 37 is formed at a position where the illustrated left end of the ring-shaped piston 31 and the illustrated right end of the cover 34 face each other, and communicates with the above-described operation line 28 via a passage 14 a in the camshaft 14. Here, the oil acting on the hydraulic chamber 37 reciprocates on the operation line 28, and the oil leaking to the space 33 via the helical splines 30c, 31a, 31b, 32a is the pressure in the space 33. To avoid high pressure,
A passage 30d is formed in the timing pulley 30 so that the outer peripheral surface of the cam shaft 14 can be lubricated.

Further, the flange portion 30e of the timing pulley 30 is press-fitted, while the inner peripheral portion of the damper case 38 comes into sliding contact with the outer peripheral surface of the transmission member 32 via the seal ring 39. here,
An annular groove is formed on the right side surface of the damper case 38 and the flange portion 32b of the transmission member 32 so as to be spaced apart from and mesh with each other to form a labyrinth portion 40, in which a viscous fluid (for example, silicone oil) is sealed. The viscous damper means 41 is formed.

Reference numerals 42 and 43 denote seal rings for sealing the viscous fluid (cooperating with the seal ring 39).

The operation of the valve timing control apparatus 10 having the above configuration will be described below.

First, when the electronic control unit 12 detects the operating state of the engine 11 based on an engine speed signal or the like, the control target value of the camshaft 14 is calculated (PID
Calculation etc.).

Next, the electronic control unit 12 detects the current valve opening / closing timing based on the output signals of the crank position sensor 15 and the cam position sensor 16, and determines the amount of change in the rotational phase of the cam shaft 14 by comparing it with the control target value.

Therefore, the electronic control unit 12 controls the first hydraulic control valve 24 and the
The duty control of the hydraulic control valve 25 is performed.

For example, when the valve opening / closing timing is advanced from the current state, the second hydraulic control valve 25 is fully closed (duty ratio, open: closed =
0: 100 / the first port 25a and the second port 25b are not communicated), and then the first hydraulic control valve 24 is controlled at the calculated duty ratio. Accordingly, high-pressure oil discharged from the second hydraulic pump 22 is supplied to the operation line 28, and the pressure acts on the hydraulic chamber 37, so that the ring-shaped piston 31 moves rightward in the drawing against the urging force of the spring 36. Move to the timing pulley
The rotational phase between the camshaft 14 and the camshaft 14 is changed. Accordingly, the valve opening / closing timing is advanced.

When the change amount of the rotation phase reaches the target value, the first hydraulic control valve 24 is also fully closed together with the second hydraulic control valve 25, thereby keeping the working line 28 in a closed state and maintaining the change amount of the rotation phase. I do.

Here, since the oil in the operation line 28 leaks from each part, the phase tends to change gradually. Therefore, the electronic control unit 12 always performs the feedback control using the hydraulic control means 23 by detecting the valve opening / closing timing.

In addition, the camshaft 14 receives the fluctuating torque in both positive and negative directions by a valve spring (not shown) disposed on the intake / exhaust valve to move the ring-shaped piston 31 in the axial direction (horizontal direction in the figure).
To change the rotation phase, but the viscous damper means 41 absorbs the fluctuation torque, so that the rotation phase does not change.

On the other hand, when retarding the valve opening / closing timing from the current
Fully close the first hydraulic control valve 24 (first port 24a and second port 2
4b and not communicate with the third port 24c), and then controls the second hydraulic control valve 25 at the calculated duty ratio. Accordingly, when the hydraulic pressure acting on the hydraulic chamber 37 is reduced, the ring-shaped piston 31 moves leftward in the figure by the urging force of the spring 36, and changes the rotation phase of the timing pulley 30 and the camshaft 14. Therefore, the valve opening / closing timing is retarded.

When the change amount of the rotation phase reaches the target value, the first hydraulic control valve 24 and the second hydraulic control valve 25 are fully closed to keep the operation line 28 in a closed state and maintain the change amount of the rotation phase. I do. The feedback control thereafter is as described above.

As described above, the electronic control unit 12 always operates the camshaft 14
The rotation phase changing means detects the position of the crankshaft 13 and the crankshaft 13 so that the optimal valve opening / closing timing is determined according to the engine state such as the engine speed, the engine load, and the engine oil temperature.
27 is linearly controlled. Therefore, the valve opening / closing timing is not binary as in the prior art, but can be any timing.

In this embodiment, the labyrinth groove is used as the viscous damper. However, the viscous damper may be of a plate type, and is not particularly limited to the labyrinth groove.

〔The invention's effect〕

As described above, according to the present invention, the valve opening / closing timing can always be set to an optimum timing by controlling the rotation phase changing means linearly by the hydraulic control means.

Furthermore, since the discharge pressure of the second hydraulic pump acts on the rotation phase changing means, even when the engine speed is low and the discharge pressure of the first hydraulic pump, which is the main pump, is low, the hydraulic pressure of the second hydraulic pump is reduced. And the high-pressure oil can be constantly supplied to the rotation phase changing means. Therefore, the responsiveness of the rotation phase changing means can be improved without the rotation phase changing means being affected by the engine speed.

Further, when the rotational phase of the camshaft is maintained, the hydraulic line and the discharge line are cut off by the hydraulic control means, and the hydraulic pressure applied to the rotational phase changing means is feedback-controlled based on the output signals of the first and second sensors. Therefore, it is possible to prevent the increase in the capacity of the first hydraulic pump by reducing the oil consumption required for the valve opening / closing timing control, to suppress the increase in the drive loss of the engine, and to accurately detect the phase shift due to the change in the hydraulic pressure of the hydraulic pump. Correction can be easily performed.

Further, by disposing a viscous fluid damper on the rotation phase changing means, it is possible to effectively absorb the fluctuation torque received by the camshaft from the valve spring.

[Brief description of the drawings]

FIG. 1 shows a configuration diagram of a valve timing control apparatus 10 according to an embodiment of the present invention. FIG. 2 shows a conventional valve timing control device 80.
FIG. 10: Valve opening / closing timing control device, 11: Engine, 12: Electronic control device, 13: Crank shaft, 14: Cam shaft, 15: Crank position sensor (second sensor), 16: Cam position sensor (1st sensor), 18 ... 1st hydraulic pump, 22 ... 2nd hydraulic pump, 23 ... hydraulic control means, 24 ... 1st hydraulic control valve, 25 ... 2nd hydraulic control valve, 26 ... Discharge line (hydraulic line), 27 ... Rotation phase change means, 28 ... Working line (hydraulic line), 30 ... Timing pulley, 31 ... Ring piston (piston means), 32 ... Transmission member, 36 ... ... spring (spring means), 41 ... viscous damper means.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-58-47131 (JP, A) JP-A-2-241914 (JP, A) JP-A-63-112 (JP, U) (58) Survey Field (Int.Cl. ⁶ , DB name) F01L 1/34 F01L 13/00 301

Claims (3)

(57) [Claims] A first sensor for detecting a rotational position of a camshaft of the engine; a second sensor for detecting a rotational position of a crankshaft of the engine; and a lubricating unit driven by the crankshaft to lubricate various parts of the engine. A first hydraulic pump for pumping oil, a second hydraulic pump driven by the crankshaft to increase the discharge hydraulic pressure of the first hydraulic pump, and the cam disposed on the camshaft with respect to a rotation phase of the crankshaft. Rotating phase changing means for changing the rotating phase of the shaft, a hydraulic line connecting the discharge side of the second hydraulic pump and the rotating phase changing means, a hydraulic control means disposed on the hydraulic line, The oil pressure control of a portion of the hydraulic line between the hydraulic control means and the rotation phase changing means and an oil pan of the engine A discharge line connected via a step,
An electronic control unit for controlling the hydraulic control unit, wherein the electronic control unit receives at least output signals of the first and second sensors and linearly controls the rotation phase changing unit by the hydraulic control unit. When the rotation phase of the camshaft is maintained, the hydraulic pressure control means cuts off the hydraulic line and the discharge line, and the hydraulic pressure at a portion of the hydraulic line between the hydraulic control means and the rotation phase changing means. A valve opening / closing timing control device that performs feedback control on the valve. 2. The valve opening / closing timing control device according to claim 1, wherein said hydraulic control means comprises first and second hydraulic control valves that are duty-controlled. 3. The rotation phase changing means includes a timing pulley, a transmission member which is engaged with the timing pulley via a piston means and is fixed to the camshaft, and moves the piston means to an initial position. Urging spring means;
3. The valve timing control device according to claim 1, further comprising viscous damper means disposed between the timing pulley and the transmission member.