JPH0799084B2 - Valve opening timing control valve device for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention appropriately adjusts the valve opening timing of intake and exhaust valves according to the operating state of an internal combustion engine, and particularly, the valve opening timing and valve opening timing of intake and exhaust valves. The present invention relates to a valve opening timing control valve operating device for an internal combustion engine capable of appropriately adjusting both the engine and the valve lift.

[Prior art]

A valve operating system for an internal combustion engine of this type is conventionally disclosed in JP-A-64-32
There is a valve train shown in Japanese Patent Publication No. 08.

In the above-mentioned conventional valve operating device, in order to adjust the valve opening timing of the intake and exhaust valves, the relative movement amount in the axial direction is relatively rotated between the shaft end of the camshaft and the cam pulley mounted on the camshaft. A hydraulic servomotor for converting into an angle amount is interposed, and a pilot valve of the hydraulic servomotor is moved in the axial direction by an operation shaft loosely fitted to a camshaft,
It was designed to change the amount of relative rotation angle between the cam pulley and the cam shaft.

[Problems to be solved]

However, the hydraulic servomotor in the valve operating device described in the above publication has a complicated structure, the number of parts is increased, and the axial position of the operation shaft is controlled by an electric signal that detects the rotation speed of the internal combustion engine. In addition, an operating axis control device was required, and the cost and weight increase were inevitable.

[Means and Actions for Solving Problems]

The present invention relates to an improvement in a valve opening timing control valve operating system for an internal combustion engine that overcomes the above problems, and a cam shaft that drives an intake / exhaust valve to open and close, and a cam shaft of the cam shaft that oscillates by contacting the cam shaft. A rocker arm that opens and closes a valve and an exhaust valve, and is concentrically fitted to the cam shaft so as to be rotatable relative to the cam shaft while being fixed in the axial direction and rotating in synchronization with the rotation of the crank shaft. In a internal combustion engine including a driven camshaft drive member, a cylinder chamber formed in an annular space between the camshaft and the camshaft drive member, and a hydraulic piston slidably fitted in the cylinder chamber. And a helical spline formed on the circumferential surface of the camshaft and the camshaft drive member facing the annular space, and is integrally coupled with the hydraulic piston. And a spring for rotating and returning the camshaft in a direction opposite to the rotation direction of the camshaft drive member so that the relative rotation angle of the camshaft with respect to the camshaft drive member becomes zero. A valve opening timing adjusting pressure control valve for adjusting the pressure of the pressure oil applied to the cylinder chamber by proportionally changing the duty ratio of the voltage applied to the coil in response to the change in the rotation speed of the internal combustion engine And a pressure-responsive actuator is configured, and a relative rotation angle of the camshaft with respect to the camshaft drive member is adjusted by the valve opening timing adjustment pressure control valve and corresponds to pressure oil applied to the actuator. It is characterized by being continuously controlled.

Since the present invention is configured as described above, when the rotational speed of the internal combustion engine increases from a low speed, the pressure oil introduced from the valve opening timing adjustment pressure control valve to the cylinder chamber changes in the engine rotational speed. The hydraulic piston is driven in the axial direction in accordance with the increase / decrease in the pressure oil in the cylinder chamber, and the cam shaft is rotationally driven along the rotational direction of the cam shaft drive member, and the cam shaft drive The valve opening timing of the intake / exhaust valve can be advanced by the advance angle of the camshaft with respect to the member, and the output characteristic suitable for the operating state of the internal combustion engine can be exhibited.

Also, in the present invention, the valve opening timing adjustment pressure control valve is applied to the cylinder chamber by proportionally changing the duty ratio of the voltage applied to the coil in response to the change in the rotation speed of the internal combustion engine. Since the pressure of the pressure oil to be adjusted is adjusted by the valve opening timing adjustment pressure control valve, no mechanical output conversion mechanism is required, the structure is greatly simplified, and cost reduction and weight reduction are easy. To be achieved.

Further, according to the present invention, by configuring as described in the second aspect of the invention, the intake and exhaust of the engine can be performed for each engine rotation speed range by using the cams having different cam shapes in addition to the adjustment of the valve opening timing. The valve opening timing, the valve lift and the valve opening period can be appropriately changed, and the output characteristics suitable for the engine operating state can be exhibited in the entire engine speed range from the low speed range to the high speed range. The adjusting pressure control valve is
Since it can be arranged at any position of the hydraulic circuit provided from the oil pump to the camshaft, the layout of the valve opening timing control device can be set easily and freely.

Furthermore, in the present invention, the scope of claim 3
With the configuration as described in the item (1), the switching operation engine speed of the plurality of cams having different cam shapes eliminates the difference in the valve opening timing due to the difference in the cam shapes, and opens the intake and exhaust valves. The valve timing can be changed continuously,
It is possible to obtain a more appropriate output characteristic according to the engine operating state.

In addition, according to the present invention, by constructing as described in the fourth aspect of the invention, the plurality of hydraulic connection switching mechanisms are sequentially operated with one hydraulic passage in response to different engine rotational speeds. Therefore, the hydraulic circuit can be remarkably simplified.

〔Example〕

An embodiment of the present invention shown in FIGS. 1 to 6 will be described below.

The engine 1 is an ignition type 4-cycle multi-cylinder internal combustion engine, in which at least one intake port 3 is formed in each cylinder in a cylinder head 2 of the engine 1, and an intake valve 5 is freely opened and closed at an intake port 4 of the intake port 3. Intake valve 5
A valve spring 7 is interposed between a flange portion 6 attached to the top end of the cylinder head 2 and the cylinder head 2, and the intake valve 5 is pressed against the intake port 4 by the spring force of the valve spring 7. It is always closed at 5.

First, the hydraulic connection switching mechanism for adjusting the valve opening period and valve lift of the intake valve by the low speed cam 10, the medium speed cam 11 and the high speed cam 12 having different cam shapes will be described. A rocker shaft 8 is mounted adjacent to the rocker shaft 8 along the cylinder arrangement direction, and a cam shaft 9 is rotatably supported above the middle of the top end of the intake valve 5 and the rocker shaft 8. For cam
A medium speed cam 11 and a high speed cam 12 are integrally formed on 10 and both sides thereof. Although only the intake valve will be described, the exhaust valve has the same structure.

Furthermore, the rocker shaft 8 has a low-speed rocker arm.
13, medium speed rocker arm 14, high speed rocker arm 15
Is rotatably fitted, and this low speed rocker arm 13,
The medium-speed rocker arm 14 and the high-speed rocker arm 15 contact the low-speed cam 10, the medium-speed cam 11, and the high-speed cam 12, respectively, and the tappet screw 16 is screwed onto the tip of the central low-speed rocker arm 13. The top end of the intake valve 5 abuts on the lower end of the tappet screw 16, and the lifter 18 of the elastic urging means 17 abuts on the lower end surfaces of the rocker arm 14 for medium speed and the rocker arm 15 for high speed. A compression coil spring 20 is interposed in the bottomed hole 19 of the cylinder head 2, and the valve spring 7 and the press-fitting coil spring 20.
The low speed rocker arm 13, the medium speed rocker arm 14 and the high speed rocker arm 15 are pressed against the low speed cam 10, the middle speed cam 11 and the high speed cam 12, respectively, by the spring force.

Furthermore, the low-speed rocker arm 13 is formed with a cylinder chamber 21 and a cylinder chamber 22 which are oriented in a direction parallel to the rocker shaft 8 and open on both side surfaces thereof.
23, a connecting pin 24 is slidably fitted, and pin holes 25, 26 are formed in the medium speed rocker arm 14 and the high speed rocker arm 15 relative to the cylinder chamber 21 and the cylinder chamber 22 of the low speed rocker arm 13. Is formed, and stoppers are formed in the pin holes 25 and 26.
27 and 28 are slidably fitted, and return springs 29 and 30 are provided in the pins 25 and 26, respectively.
When the pressure oil is not supplied to 22, the connecting pins 23 and 24 are pushed deeply into the cylinder chambers 21 and 22 via the stoppers 27 and 28, and the connecting pins 23 and 24 and the stoppers 27 and 28 are
The contact surface with is located in the middle of the interval between the low speed rocker arm 13, the medium speed rocker arm 14, and the high speed rocker arm 15, and the stoppers 27 and 28 slide relative to the connecting pins 23 and 24. You can do it.

Moreover, an oil passage 31 is formed in the rocker shaft 8, and the oil passage 31 communicates with the cylinder chamber 21 and the cylinder chamber 22.

Next, a mechanism for adjusting the valve opening timing of the intake system according to claim 1 will be described.

Helical splines 33, 34 in opposite directions are formed on the inner peripheral surface of the cylindrical housing 32 and the outer peripheral surface of the end portion of the cam shaft 9 at one end of the cam shaft 9, and the annular space between the cam shaft 9 and the housing 32 is formed. The hydraulic piston 35 is slidably and rotatably fitted in the oil-tight manner, and
Helical splines 36 and 37 formed on the base portion 35a of the above are fitted to the helical splines 33 and 34, and the compression coil spring 38 is fitted to the inner surface of the outer end of the housing 32 and the outer end surface of the hydraulic piston 35.

Further, a pulley 39 is integrally formed on the outer peripheral surface of the housing 32, and a belt 40 is bridged between the pulley 39 and a drive pulley (not shown) which is integral with a crankshaft. Is designed to be rotated.

A gear train is used instead of the belt drive system
The 32 may be driven to rotate.

Further, the cylinder chamber 41, which is divided by the inner end of the housing 32 and the inner end of the hydraulic piston 35, has an oil passage 42 provided in the camshaft 9 and a cam holder 43 of the cylinder head 2.
Is connected to an oil sump 46 via an oil passage 44 provided in the cylinder head 2 and an oil passage 45 in the cylinder head 2, and an oil pump 47 is provided in the oil passage 45 and a valve opening timing adjusting pressure control valve 48 is provided on the discharge side thereof. The pressure oil discharged from the oil pump 47 is maintained at a constant oil pressure by a pressure adjusting valve (not shown) and is applied to the cylinder chamber 41.

As shown in FIG. 6, the valve opening timing adjustment pressure control valve 48
Includes a valve casing 49, a spool 50 slidably fitted on the valve casing 49, a compression coil spring 51 for biasing the spool 50 to one side, and a diaphragm 52 stretched on the opposite side of the compression coil spring 51. Is composed of a spool 50, a plunger 53 slidably fitted on the opposite side, and a coil 54 for urging the plunger 53 toward the spool 50.
By intermittently applying a pulse voltage to the control pressure port 56, the pressure oil is supplied to the control pressure port 56, and the remaining pressure oil can be discharged from the drain port 57.

In this valve opening timing adjustment pressure control valve 48, by proportionally changing the duty ratio of the pulse voltage applied to the coil 54,
The pressure applied to the cylinder chamber 41 is adjusted.

Further, in the coil 54 of the valve opening timing adjustment pressure control valve 48, the connecting pin 23 in the cylinder chamber 21 is fitted into the pin hole 25 in response to the increase in the number of rotations in each of the low speed region, the medium speed region and the high speed region. The duty ratio of the pulse voltage can be switched to 0 when they are matched with each other and when the connecting pin 24 in the cylinder chamber 22 is fitted into the pin hole 26 by reaching the medium speed range to the high speed range.

Further, an oil passage communicating with the oil passage 31 of the rocker shaft 8 is also provided with a valve opening / closing characteristic adjusting pressure control valve 58 having the same structure as the valve opening timing adjusting pressure control valve 48, and is proportional to the rotation speed of the engine 1. Pressure oil of the selected pressure is in the oil passage
It is supplied to the cylinder chambers 21 and 22 via 31.

Since the embodiment shown in FIGS. 1 to 6 is configured as described above, when the engine 1 is operated in the idling state, the valve opening timing adjusting pressure control valve 48, the valve opening / closing characteristic adjusting pressure are adjusted. The control valve 58 is shut off, and the pressure oil is not supplied to the cylinder chambers 21, 22 and the cylinder chamber 41.

Therefore, the connecting pins 23 and 24 retreat into the cylinder chambers 21 and 22,
The low-speed rocker arm 13, the medium-speed rocker arm 14, and the high-speed rocker arm 15 are separated from each other, and the intake valve 5 is driven by the low-speed rocker arm 13 to open and close with a valve lift and a valve opening period suitable for a low speed range. To be done.

Further, the hydraulic piston 35 is pushed inward by the spring force of the compression coil spring 38 so that the cylinder chamber 41 becomes the narrowest, and the intake valve 5 is opened / closed with the opening timing of the intake valve 5 being most delayed.

Then, as the rotational speed of the engine 1 increases beyond a certain rotational speed, the spring force of the compression coil spring 38 is exerted by the pressure of the pressure oil in the cylinder chamber 41 controlled by the valve opening timing adjustment pressure control valve 48. The hydraulic piston 35 moves outward, and when the pressure of the pressure oil in the cylinder chamber 41 and the spring force of the compression coil spring 38 are balanced, the hydraulic piston 35 stops, and the amount of movement increases in rotation speed. The valve opening timing of the intake valve 5 is advanced.

Further, when the engine speed reaches the medium speed range, the pressure in the oil passage 31 controlled by the valve opening / closing characteristic adjusting pressure control valve 58 rises, and the connecting pin 23 in the cylinder chamber 21 causes the return spring 29 to spring. It overcomes the force and protrudes and fits into the pin hole 25,
The low-speed rocker arm 13 and the medium-speed rocker arm 14 are integrally connected, and the intake valve 5 is driven to open and close with a valve lift larger than that in the low-speed range and a long valve opening period. It can be operated in the exhaust state. Engine 1
Of the pulse voltage applied to the coil 54 of the valve opening timing adjustment pressure control valve 48 when the rotation speed of the low speed region reaches the medium speed region and the low speed rocker arm 13 is switched to the medium speed rocker arm 14. The duty ratio becomes 0 and the hydraulic piston 35
Double-acts to the original position, and the duty ratio of the pulse voltage to the coil 54 of the valve opening timing adjustment pressure control valve 48 increases as the rotation speed of the engine 1 increases in the medium speed range.

Furthermore, when the number of revolutions of the engine 1 reaches from the medium speed range to the high speed range, the duty ratio of the pulse voltage applied to the coil 54 of the valve opening timing adjustment pressure control valve 48 becomes 0 again, and at the same time the valve opening / closing characteristic adjustment is performed. The pressure in the oil passage 31 controlled by the pressure control valve 58 further rises, and the connecting pin 24 in the cylinder chamber 22 overcomes the spring force of the return spring 30 and projects to fit into the pin hole 26. The arm 13 and the high-speed rocker arm 15 are integrally connected, and the intake valve 5 is driven to open and close with a valve lift larger than that in the medium speed range and a long opening period.
The engine 1 can operate in an intake / exhaust state suitable for a high speed range.

And the cylinder chamber 2 for controlling the medium speed range and the high speed range
Since 1,22 is connected to only one oil passage 31,
Instead of two pressure oil passages, one pressure oil passage is provided, which simplifies the oil circuit and reduces costs.

Also, in the low speed range, medium speed range and high speed range, the intake and exhaust valves are opened and closed with the corresponding valve lift and opening period,
In addition, in each speed range, the valve opening timing is appropriately adjusted according to the increase or decrease in the rotation speed of the engine 1, so that the engine 1 can be operated in an appropriate intake / exhaust state from the low speed range to the high speed range. .

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment of a valve opening timing control valve operating system for an internal combustion engine according to the present invention, and FIGS. 2 and 3 are lines II-II and III-III in FIG. Fig. 4 is a cross-sectional side view cut along the line, Fig. 4 is a cross-sectional plan view cut along the line IV-IV in Fig. 2, Fig. 5 is a vertical side view of the left side of Fig. 1, and Fig. 6 is a control valve. It is a vertical side view. 1 ... Engine, 2 ... Cylinder head, 3 ... Intake port, 4 ... Intake port, 5 ... Intake valve, 6 ... Collar part,
7 ... Valve spring, 8 ... Rocker shaft, 9
…… Cam shaft, 10 …… Low speed cam, 11 …… Medium speed cam, 12 …… High speed cam, 13 …… Low speed rocker arm,
14 …… Medium speed rocker arm, 15 …… High speed rocker arm, 16 …… Tappet screw, 17 …… Bullet urging means, 18…
… Lifter, 19… Bottom hole, 20… Pressure coil spring, 21… Cylinder chamber, 22… Cylinder chamber, 23… Connecting pin, 24… Connecting pin, 25… Pin hole, 26… … Pin holes,
27 …… Stopper, 28 …… Stopper, 29 …… Return spring, 30 …… Return spring, 31 …… Oil passage, 31
…… Oil passage, 32 …… Housing, 33,34 …… Spline, 35 …… Hydraulic piston, 36,37 …… Helical spline, 38 …… Compression coil spring, 39 …… Pulley, 40
...... Belt, 41 …… Cylinder chamber, 42 …… Oil passage, 43
...... Cam holder, 44,45 ...... Oil passage, 47 ...... Oil pump, 48 ...... Valve opening timing adjustment pressure control valve, 49 ...... Valve casing, 50 ...... Spool, 51 ...... Compression coil spring, 52 ... … Diaphragm, 53 …… Plunger, 54…
… Coil, 55 …… Supply pressure port, 56 …… Control pressure port,
57 …… Drain port, 58 …… Pressure control valve for adjusting valve opening / closing characteristics.

Claims (4)

[Claims] 1. A cam shaft for opening and closing an intake / exhaust valve, a rocker arm for contacting a cam of the cam shaft and swinging to open / close an intake valve and an exhaust valve, and fixed axially to the cam shaft. An internal combustion engine including a camshaft drive member that is concentrically fitted to the camshaft so as to be relatively rotatable as it is, and is rotationally driven in synchronization with rotation of a crankshaft. A cylinder chamber formed in the annular space between the drive members, a hydraulic piston slidably fitted in the cylinder chamber, and the cam shaft facing the annular space and the peripheral surface of the cam shaft drive member. Screwing member that is screwed into the helical spline and integrally connected to the hydraulic piston, and the camshaft with respect to the camshaft drive member. A spring for rotating and returning the camshaft in a direction opposite to the rotation direction of the camshaft drive member so that the relative rotation angle becomes zero, and a spring applied to the coil in response to a change in the rotation speed of the internal combustion engine. Pressure-actuated actuator is configured with a valve opening timing adjustment pressure control valve that adjusts the pressure of the pressure oil applied to the cylinder chamber by proportionally changing the duty ratio of the voltage applied to the camshaft drive member. A valve opening of an internal combustion engine, wherein a relative rotation angle of the camshaft is adjusted by the valve opening timing adjusting pressure control valve and continuously controlled corresponding to pressure oil applied to the actuator. Timing control valve device. 2. The camshaft is provided with a plurality of cams having different cam shapes with respect to one or both of the intake and exhaust valves for each intake valve and exhaust valve, and the rocker arm is also provided with the same. A number of rocker arms corresponding to the number of cams are provided, and a hydraulic connection switching mechanism for selectively connecting or disconnecting the plurality of rocker arms is provided, and the rotation speed of the internal combustion engine is set to a predetermined value. 2. A valve opening timing control for an internal combustion engine according to claim 1, further comprising a valve opening / closing characteristic firing pressure control valve for operating any of the hydraulic connection switching mechanisms when the rotational speed is reached. Valve drive. 3. The pressure applied to the valve opening timing adjusting pressure control valve increases proportionally in response to an increase in the rotational speed of the internal combustion engine, and the hydraulic connection switching mechanism of the rocker arm is switched to a switching state. 3. The internal combustion engine according to claim 2, wherein the valve-opening timing adjustment pressure control valve operates so as to increase proportionally again when the engine rotation speed in the switching operation further increases. Valve opening timing control valve operating device. 4. The applied pressure of the valve opening / closing characteristic adjusting pressure control valve gradually increases stepwise at the switching operation rotational speed of the plurality of hydraulic connection switching mechanisms, and the plurality of hydraulic connection switching mechanisms differ. The valve opening timing control device for an internal combustion engine according to claim 3, wherein the device operates with hydraulic pressure.