JPH07310514A - Valve drive - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a valve drive device capable of smoothly switching the valve lift amount continuously. An engine valve including intake and exhaust valves 3 and 4, one end of which is pressed by cams 7 and 8 by a biasing amount of a spring 20 and the other end of which drives the engine valves 3 and 4 and an engine main body side 2 A rocking member 9, whose both ends are rockably supported,
10, fulcrum support control means 12, 13, 18, 19 for changing the rotation center of the swinging members 9, 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve drive system for an internal combustion engine, and more particularly to a valve drive system capable of changing the valve lift of intake and exhaust valves in accordance with the operating range of the engine.

[0002]

2. Description of the Related Art While an internal combustion engine is operating, it has been proposed to drive an intake / exhaust valve with a valve lift amount and opening / closing timing suitable for an engine operating range to improve output. For example, as described in the specification and drawings of the patent application filed on February 28, 2004 by the present applicant, the low speed cam or the high speed cam is selectively switched and driven, and the output is reduced and fuel consumption is reduced in a timely manner. In order to achieve the above, there is known an internal combustion engine provided with an intake / exhaust valve variable mechanism that can perform cylinder deactivation operation by stopping intake and fuel supply to some cylinders.

The intake / exhaust valve variable mechanism of this internal combustion engine is shown in FIG.
1, as shown in FIG. 12, a low speed rocker arm 114 driven by a low speed cam 112, a high speed rocker arm 115 and a fixed rocker arm shaft 116 driven by a high speed cam 113.
And a rocker arm shaft 107 integral with the. The fixed rocker arm shaft 116 has a pair of intake ends 103,
3 is opened and closed. The low-high rocker arms 114 and 115 have rollers pivotally attached to their rotating ends, and the low-high cam 11 is attached to the rollers.
2, 113 are provided opposite to each other, and the low-high switching means ML,
MH is installed. The low / high switching means ML and MH are pins 1 slidably supported in the accommodation holes of the rocker shaft 107.
The hydraulic chamber 12 for switching the pins 17 and 118 by hydraulic pressure against the elastic force of the springs 119 and 120.
1, 122 and the switching oil passage 12 communicating with each hydraulic chamber
3, 124 and low and high solenoid valves 126, 12 which connect each switching oil passage to the hydraulic pump side (not shown) in an intermittent manner.
7 and 7. In the low / high switching means ML, MH, when the low / high electromagnetic valves 126, 127 are both off, only the low-speed rocker arm 114 is integrated with the fixed rocker arm shaft 116 side via the pin 117 at the locking position L1, and the intake valve 103 is operated at low speed. When driven in the operating range and the low and high solenoid valves 126 and 127 are both turned on, the pin 117 reaches the non-locking position L2 and the pin 11
8 reaches the locking position H2, and only the high speed rocker arm 115 is integrated with the fixed rocker arm shaft 116 side.
When 03 is driven in the high speed operation range and only the low solenoid valve 126 is turned on, the pin 117 is retracted to the non-locking position L2, the pin 118 is held at the non-locking position H1, and the cylinder deactivation operating range is achieved.
Here, when the cylinder deactivation operation range is entered, the opening and closing operations of the intake and exhaust valves of the cylinder deactivation cylinder are stopped and the fuel supply to the cylinder deactivation cylinder is stopped. The opening / closing operation of the valve is returned to the normal state, and the fuel supply to the deactivated cylinder is restarted. Furthermore, even in the all cylinder operation, the low speed cam is used to drive the intake and exhaust valves with a relatively low lift amount in the low speed operation range to prevent the intake and exhaust valves from overlapping and improve the volume efficiency at low speeds, thus enabling high speed operation. In the region, the intake / exhaust valve is driven with a relatively high lift by using a high speed cam to improve the volumetric efficiency at high speed, and the output can be improved in each engine operating state.

Further, Japanese Utility Model Publication No. 3-23724 discloses an intake / exhaust valve which is opened / closed by a drive cam via a rocker arm, and in particular, a control cam is continuously provided via a lever which comes into fulcrum contact with the back surface of the rocker arm. To be done. Here, the lever moves up and down on the turning end side according to the turning of the control cam. Therefore, the gap between the lever and the back surface of the rocker arm that makes fulcrum contact increases or decreases, the opening / closing timing of the valve changes, and the position at which the rocker arm back surface and the lever make fulcrum contact also displaces, increasing or decreasing the valve lift amount. That is.

[0005]

As described above, the variable intake / exhaust valve mechanism of the internal combustion engine shown in FIG. 11 can be switched to a low speed operation range, a high speed operation range, and a cylinder deactivation operation range. Switching to is performed discontinuously. For this reason, the output fluctuation easily occurs at the time of switching, and the exercise performance is impaired. Moreover, by using the above-mentioned low / high switching means ML, MH,
If the high-speed operating range is switched by engaging and disengaging the switching pin, the low-high switching means ML and MH have low assembly accuracy, the operation timing shifts, and the parts wear over time, resulting in smooth operation. There is a case in which engagement and disengagement of the switching pin cannot be performed, which is a problem. On the other hand, in the intake / exhaust valve drive device disclosed in Japanese Utility Model Publication No. 3-23724 in which a control cam is connected to the rear surface of the rocker arm via a lever, the rear surface of the rocker arm that makes fulcrum contact with the lever for each intake / exhaust stroke. There is a problem that slippage occurs between the lever and the rocker arm, and the lever ratio changes as the fulcrum contact position between the lever and the rear surface of the rocker arm shifts, causing durability problems and stabilizing the valve lift amount. .

A first object of the present invention is to provide a valve drive device capable of smoothly switching the valve lift amount continuously. A second object is to provide a valve drive device capable of continuously increasing or decreasing the valve lift amount and smoothly changing the valve lift amount continuously by a cam member. A third object is to provide a valve drive device capable of smoothly switching the valve lift amount continuously and reliably operating the swing member.

A fourth object of the present invention is to provide a valve drive device capable of smoothly switching the valve lift amount continuously and stopping the valve. A fifth object is to reliably provide a valve drive device capable of smoothly switching the valve lift amount continuously. A sixth object is to provide a valve drive device capable of smoothly switching the valve lift amount and facilitating the layout. A seventh object is to provide a valve drive device capable of smoothly switching the valve lift amount continuously and particularly facilitating the layout for a V-type engine. 8th
It is an object of the present invention to provide a valve drive device capable of smoothly switching the valve lift amount continuously according to the operating range information.

A ninth object is to provide a valve drive device capable of smoothly switching the valve lift amount continuously, and in particular, capable of stably operating the cam member and the cam member contact side surface. A tenth object is to provide a valve drive device capable of smoothly switching the valve lift amount continuously, and in particular, capable of stably operating the engine valve side contact surface of the rocking member and the engine valve shaft. It is in. An eleventh object is to provide a durable valve drive device capable of smoothly switching the valve lift amount continuously.

[0009]

In order to achieve the above-mentioned object, according to the invention of claim 1, an engine valve comprising intake and exhaust valves,
A swing member whose one end is pressed by the cam by the biasing amount of the spring, the other end drives the engine valve, and both ends of which are swingably supported on the engine body side, and the swing member of the swing member. A fulcrum support control means for changing the center of motion is provided.

According to a second aspect of the present invention, in the valve drive device according to the first aspect, the fulcrum support control means includes a cam member that abuts on a rotation center of the swing member. According to a third aspect of the invention, in the valve drive device according to the first aspect, the swinging member is swung by being guided by a notch provided in the casing. Claim 4
In the invention of claim 2, in the valve drive device according to claim 2,
The cam member is in contact with a portion of the swing member located on the axis of the engine valve to stop the valve.
According to a fifth aspect of the present invention, in the valve drive device according to the second aspect, the fulcrum support control means includes a plurality of shafts each provided with the cam member, and an actuator that rotates each shaft. The operation mode of the engine valve is different.

According to a sixth aspect of the invention, in the valve drive device according to the fifth aspect, the plurality of shafts are coaxially arranged, and the actuator is arranged at an end of the shaft. To do. According to a seventh aspect of the invention, in the valve drive system according to the fourth aspect, the engine valves are respectively provided in V banks of a V-type engine, and the engine valves of one bank are stopped. . According to an eighth aspect of the invention, in the valve drive system according to the first aspect, the cam member controls switching of the rotation angle of the swinging member according to the engine speed and the accelerator pedal depression amount.
According to a ninth aspect of the present invention, in the valve drive device according to the second aspect, the cam member contacting side surface of the swinging member is formed as an arc having a radius centered on the cam member center point. . According to a tenth aspect of the invention, in the valve drive device according to the ninth aspect, the contact surface of the rocking member on the engine valve side is that the cam member is in contact with the rocking member on the engine valve shaft. It is characterized in that it is formed by an arc having a centered radius.
According to an eleventh aspect of the invention, in the valve drive device according to the first aspect, the swinging member is in contact with the cam via a roller.

[0012]

According to the first aspect of the invention, the fulcrum support control means changes the center of rotation of the swing member, so that the valve lift amount of the engine valve changes continuously. According to the invention described in claim 2, in the valve drive device according to claim 1, since the cam member included in the fulcrum support control means changes the rotation center of the swinging member, the valve lift amount of the engine valve is particularly stable. To do.
According to the third aspect of the invention, in the valve drive device according to the first aspect, the swinging member is swung by being guided by the notch, so that the swinging member is particularly reliably operated.

According to the fourth aspect of the invention, in the valve drive system according to the second aspect, the cam member abuts a portion of the swing member located on the axis of the engine valve, so that the valve can be stopped in particular. And According to the invention described in claim 5, in the valve drive device according to claim 2, the fulcrum support control means includes a plurality of shafts provided with cam members and an actuator for rotating each shaft, and the engine valve The valve lift amount of the engine valve continuously changes because the operating modes of the above are different. According to the invention described in claim 6, in the valve drive device according to claim 5, the plurality of shafts are arranged coaxially, and the actuator is arranged at an end of the shaft. To do.

According to the seventh aspect of the invention, in the valve drive system according to the fourth aspect, the engine valve of one bank of the V-type engine is stopped so that the V-type engine can be installed in particular. Be seen. According to the invention described in claim 8, in the valve drive device according to claim 1, the cam member controls the switching of the rotation angle of the rocking member according to the engine speed and the accelerator pedal depression amount. The valve lift of the engine valve changes continuously.

According to the invention described in claim 9, in the valve drive device according to claim 2, the cam member contacting side surface of the rocking member is formed by an arc of a radius centered on the cam member center point. There is no variation in the valve lift amount when the cam member and the cam member contact side surface are in contact with each other. According to the invention described in claim 10, in the valve drive device according to claim 9, a radius around the point where the engine valve side contact surface of the rocking member contacts the rocking member on the engine valve shaft is set. Since it is formed by a circular arc, there is no fluctuation in the valve lift amount when the engine valve side contact surface and the engine valve shaft are in contact. According to the invention described in claim 11, in the valve drive device according to claim 1, since the rocking member contacts the cam via the roller, uneven wear does not occur.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The valve drive system shown in FIGS. 1 and 2 is installed in an in-line 4-cylinder internal combustion engine (hereinafter simply referred to as engine 1) equipped with a DOHC type valve train MV. Each cylinder is shown in the cylinder head 2 of the engine 1 (shown as c1 to c4)
An intake passage Ri and an exhaust passage Re which can communicate with each other are formed, and these passages are opened and closed by an intake valve 3 and an exhaust valve 4. The valve train MV of the engine 1 is a cylinder head 2
Intake / exhaust cam shafts 5 and 6 provided therein, a support base 11 arranged above the intermediate portions of both cam shafts, and intake and exhaust side fulcrum shafts 12 arranged near both sides of the support base 11. 13, and these are arranged in parallel facing each other.

The support base 11 has a long frame shape, and is provided with left and right upper side plates 111 and 112 between front and rear pillar portions 113 thereof, and the front and rear pillar portions 113 are bolted to a lower wall in the cylinder head 2. The intake-side and exhaust-side fulcrum shafts 12 and 13 are integrally provided with cam members 18 and 19 forming a part of fulcrum support control means, which will be described later, at respective cylinder facing positions. Timing sprockets 14 and 15 are integrally attached to one ends of the camshafts 5 and 6, and these timing sprockets 14 and 15 are connected to a crankshaft side (not shown) via a timing belt 16 so that half of engine rotation is achieved. It is configured to rotate both cam shafts at the rotational speed of. Here, the cam shafts 5 and 6 are provided with intake / exhaust cams 7 and 8 for opening and closing the intake valve 3 and the exhaust valve 4 at the cylinder facing positions, respectively. 3 and the valve stem of the exhaust valve 4 are configured to apply a pressing force.

Here, the rocking members 9, 10 are formed with sliding ends 901, 902, 101, 102 at both ends,
Each roller 17 is pivotally supported at a portion facing the suction / discharge cams 7, 8 and is in roller contact with the suction / discharge cams 7, 8 via each roller 17. Moreover, the swinging members 9 and 10 have the rollers 17 sucking and discharging the cams 7 and 8
Engines that are formed with spring bearings 905, 105 of the respective springs 20 that press against each other, and further contact cam member contact side surfaces 903, 103 that contact the cam members 18, 19 and valve stems of the intake valve 3 and the exhaust valve 4. Valve-side contact surfaces 904 and 104 are formed, respectively. Each spring receiver 90 of the rocking members 9 and 10
Each spring 20 whose one end is supported by 5, 105 is a support base 11
Spring receivers 11 formed on the upper side plates 111 and 112 of the
The other end is supported by 9, 119. Such springs 20 always suck the exhaust cams 7, 8 at both ends of the swinging members 9, 10.
And elastically presses and urges the intake valve 3 and the exhaust valve 4.

Sliding ends 901, 101 of the rocking members 9, 10
Is formed in a vertically oriented piece having a constant thickness, and is held in the notched guide grooves 21 and 22 of the cylinder head 2 so as to be vertically slidable in a state where lateral displacement is restricted. Here, the guide groove 2
Reference numerals 1 and 22 each have a vertical groove shape, are formed on the inner wall of the cylinder head 2, and are sequentially formed at the facing positions of the sliding ends 901 and 101 of the swinging members 9 and 10. Similarly, the swing members 9 and 1
The sliding ends 902 and 102 of 0 are formed in a vertically oriented piece shape having a constant thickness, and are held by the notched guide grooves 23 and 24 of the support base so as to be slidable up and down in a state where lateral displacement is restricted. Here, the guide grooves 23 and 24 are U-shaped in a plan view, and are formed so as to project from the front and back of the lower end of the vertical wall 114 of the support base, and the sliding ends 902 and 102 of the swinging members 9 and 10 respectively. Sequentially formed at opposing positions.

The engine valve side contact surface 90 of the rocking members 9, 10
4, 104 are points pi and pe at which the cam members 18 and 19 contact the swinging members 9 and 10 on the axes of the intake valve 3 and the exhaust valve 4, respectively.
It is formed by an arc having a radius of r. Therefore, even if the rocking members 9 and 10 rock in the state of cylinder deactivation when the cam members 18 and 19 are in contact with the points pi and pe, the engine valve side contact surface 9
04 and 104 do not change the lift amount (zero at this time) of the intake valve 3 and the exhaust valve 4. Swing member 9, 1
No. 0 cam member contact side surfaces 903, 103 are cam members 18,
It is formed by an arc having a radius centered on the center points Oi and Oe of 19. By forming the cam member contact side surfaces 903 and 103 in an arc shape, when the cam members 18 and 19 are selectively rotationally switched to the low speed position A1, the high speed position A2, and the cylinder deactivation position A3, the cam member is rotated. The sliding resistance between the cams 18, 19 and the cam member contact side surfaces 903, 103 can be made relatively low, and a smooth switching to a predetermined position can be performed.

As shown in FIG. 2, the intake-side and exhaust-side fulcrum shafts 12 and 13 are constituted by center shafts 121 and 131 and cylindrical outer shafts 122 and 132, respectively, and are arranged on a coaxial line. A plurality of bearing members 24, 2 in the head 2
Pivoted to 5. Of these, the inner shafts 121 and 13 respectively
Reference numeral 1 denotes each cam member 1 for the second and third cylinders, which are deactivated cylinders.
8 and 19 are integrally attached and each step motor M
It is rotated by 1. Each outer shaft 122, 1
Reference numeral 32 integrally mounts the cam members 18 and 19 of the first and fourth cylinders, and is rotated by each step motor M2. In particular, the opening 12 is provided at the center of the outer shafts 122 and 132.
3, 133 are formed, and the cam members 18, 19 for the second and third cylinders on the side of the center shafts 121, 131 project from the inside through the openings 123, 133, respectively. Each opening 1
The outer peripheral widths of 23 and 133 are set to allow relative displacement of the outer shafts 122 and 132 and the cam members 18 and 19 for the second and third cylinders.

The stepping motors M1 and M2 are for controlling the rotation angle stepwise by applying a predetermined pulse signal to a coil of a stator (not shown) in the casing. For example, as shown in FIGS. 4 (a) and 4 (b), the step motor M1 holds the cam members 18 and 19 of the center shafts 121 and 131 interlocked with the rotor (not shown) at zero cylinder steps at the cylinder deactivation position A3, and performs n1 steps. At high speed position A2, n1
/ A step holds the low speed position A1. Similarly, the step motor M2 has a structure in which the cam members 18 and 19 of the outer shafts 122 and 132 which are interlocked with the rotor (not shown) are held at the low speed position A1 at zero steps and are held at the high speed position A2 at n2 steps. The step motors M1, M
2 is connected to an engine control unit (ECU) 30 as a step number control means.

Engine control unit (ECU)
Reference numeral 30 denotes a microcomputer, the main part of which is configured to perform engine operation control processing. Here, in particular, as a driving range detecting means, a low speed driving range a1 (see FIG. 3) in which the valve lift amount is relatively small, or a valve lift is used. A high speed operation range a2 (see FIG. 3) in which the amount is relatively large or a cylinder deactivation operation range a3 (see FIG. 3) in which the valve lift amount is held at zero is detected, and each operation region information is output to perform switching control. As a means, it has a function of outputting a switching signal to the operating area switching means when there is a difference between the current operating area set according to the operating information and the previously detected previous operating area.

The ECU 30, as shown in FIG.
The engine rotation sensor 31, the load sensor 32, and the crank angle sensor 33 detect the engine rotation speed Ne and the accelerator opening degree θa as a load signal, respectively. ECU
An operating range setting map (a characteristic diagram of which is shown in FIG. 3) is stored and stored in a ROM (not shown) of 30. Using this map, the engine speed Ne and the load signal θa are lower than the operating range and the operating speed is high. Area, cylinder deactivation operation area can be calculated. Further, a ROM (not shown) of the ECU 30 has a conversion position-step number conversion map of the step motors M1 and M2 (see FIG. 4).
(A) and (b) show characteristic maps of the same map) are stored. Here, the operation of the valve drive device as one embodiment of the present invention will be described.

When the engine of FIGS. 1 and 2 is driven, EC
U30 controls the fuel supply system and the ignition system,
The operating range switching subroutine is executed at a predetermined timing. In the operating range switching subroutine, for example, as shown in FIG. 6, the engine speed Ne and the load signal θa in the various operating information are fetched in step a1. At step a2, the current engine speed Ne is used by using the operating range setting map.
And an operating range a _n according to the load signal θa. In step a3, it is judged whether or not the previous driving range a _{(n-1) and the} current driving range a _n match. If they match, the control is terminated as it is, and if different, the process proceeds to step a4. Steps a4, a
5 At step motor M1 in accordance with the current operating region a _n,
The step number n of M2 is taken in by the switching position-step number conversion map (see FIGS. 4A and 4B), and the pulse output of that step number is output to each step motor M
1 and M2, and one control process is completed. As a result, the step motors M1, M2 are
Also, the cam members 18, 19 of the outer shafts 122, 132 are switched and held in the current operating range.

For example, if the current operating range is the low speed operating range,
Both the step motors M1 are driven in n1 / 2 steps to keep the cam members 18 and 19 at the low speed position A1, and the both step motors M2 are switched to the zero step, so that each cam member 1 is driven.
8 and 19 are held at the low speed position A1. At this time, the tip ends of the cam members 18, 19 have cam member contact side surfaces 903,
Sliding along 103 from the previous position to the current low speed position A1. At that time, the cam member contact side surfaces 903, 10
Since 3 is formed by an arc having a radius centered on the center points Oi and Oe of the cam members 18 and 19, the sliding operation of the cam members 18 and 19 is relatively smooth. Further, the lever ratios of the rocking members 9 and 10 are continuously changed and switched to the lever ratio at the low speed position A1 this time, and the valve lift amounts of the intake valve 3 and the exhaust valve 4 are gradually changed.

When the current operating range is the high speed operating range a2, both step motors M1 are driven in n1 steps to hold each cam member 18, 19 at the high speed position A2, and both step motors M2 are driven in n2 steps. Each cam member 18, 1
9 is held at the high speed position A2. Also at this time, each cam member 1
The tip portions of 8 and 19 can relatively smoothly slide from the previous position to the high speed position A2 of this time, and the lever ratio of the swing members 9 and 10 is switched to the lever ratio of the high speed position A2 of this time.
The valve lift amounts of the intake valve 3 and the exhaust valve 4 also gradually change. When the current operating range is the cylinder deactivation operating range a3, both step motors M1 are held at zero step, the cam members 18, 19 are held at the cylinder deactivating position A3, and both step motors M2 are held at zero step. Cam members 18, 19
Is held at the low speed position A1.

Also at this time, the tip portions of the cam members 18, 19 can relatively smoothly slide from the previous position to the cylinder deactivation position A3 and the low speed position A1 of this time, and the lever ratios of the rocking members 9, 10 this time. The cylinder deactivation position A3 and the low speed position A1 are switched to zero, and the valve lift amounts of the intake valve 3 and the exhaust valve 4 gradually change toward zero. In the above description, the fulcrum support control means are the cam members 18, 1 respectively.
9 inner shafts 121 and 131 and cylindrical outer shafts 122 and 1
Intake side and exhaust side fulcrum shafts 12 and 13 composed of 32,
The step motors M1 and M2 for driving the inner shafts 121 and 131 and the outer shafts 122 and 132 are provided.

As a first modified example of the first embodiment, as shown in FIG. 7, the fulcrum support control means includes intake side and exhaust side fulcrums in which intake side and exhaust side cam members 18 and 19 are provided for each cylinder. The shafts 12a and 13a and the step motors M1a and M2a for driving the fulcrum shafts 12a and 13a may be provided, respectively. The step motors M1a and M2a here are mounted in the cylinder head 2a,
The switching control is performed by the ECU 30 similarly to the step motors M1 and M2 in FIG. Even when the fulcrum support control means is provided for each cylinder in this way, the same effect as that of the first embodiment can be obtained.

In the above description, the swing members 9, 10
The cam member contacting side surfaces 903 and 103 have the cam member 1
Although it was formed of an arc having a radius centered on the center points Oi and Oe of 8 and 19, as a second modification of the first embodiment,
As shown in FIG. 8, the cam member contacting side surface 9 of the swinging member 9b.
03b is formed by being displaced by an amount of deviation t with respect to an arc having a radius centered on the center point Oi of the cam member 18. That is, the cam member contact side surface 903b here is at the high speed position A.
2 is formed as a curved surface having a radius close to the distance from the center point Oi of the cam member 18 to the tip end portion, and at a low speed value A1, the amount of deviation from the center point Oi of the cam member 18 to the tip end portion. The curved surface is formed as a curved surface having a radius close to the interval to which t is added, and even at the cylinder deactivation position A3, a curved surface having a radius close to the interval from the center point Oi of the cam member 18 to the tip portion and a deviation amount t. Formed as.

When the cam member contacting side surface 903b and the exhaust side cam member contacting side surface (not shown) are formed, the tips of the cam members 18 and 19 (see FIG. 1) reach the high speed position A2. At this time, as shown in FIG. 9B, the lift start timings te and ti of the intake valve 3 and the exhaust valve 4 are set.
Is relatively quick, and the overlap area OL of both valves is also relatively large. On the other hand, the tip ends of the cam members 18 and 19 are at the low speed position A.
When it reaches 1, as shown in FIG. 9A, the lift start timings te and ti of the intake valve 3 and the exhaust valve 4 are relatively delayed according to the deviation amount t, and the valve lift amount is also the deviation amount t. Therefore, the overlap area of both valves is deleted (or reduced). When the tip ends of the cam members 18 and 19 reach the cylinder deactivation position A3, as shown in FIG. 9C, the tip parts are separated from the cam member abutting side surface 903 by the shift amount t and surely. Hold the cylinder in a resting state.

Thus, the cam member contacting side surface 903b and the exhaust side cam member contacting side surface (not shown) are the cam member 18,
The same operational effect as that of the first embodiment can be obtained when the displacement amount t is maintained with respect to the front end portion of 19. In particular, this deviation amount t is reduced at the high speed position A2, the valve lift amount of the intake valve 3 and the exhaust valve 4 is maximized to widen the valve opening timing, and the filling efficiency in the high speed operation range a2 is ensured to reduce the low speed. At the position A1, the shift amount t is sufficiently secured to reduce (or eliminate) the overlap between both valves to secure the charging efficiency in the low speed operation range. Further, the shift amount t can be secured even at the cylinder deactivated position A3, and a stable cylinder deactivated condition can be ensured. FIG. 10 shows a second embodiment of the present invention.

The valve drive device shown in FIG. 10 includes many similar components as compared with the valve drive device shown in FIG. 1. Here, the same members are denoted by the same reference numerals, and redundant description will be omitted. Here, the valve drive system according to the second embodiment is installed in an in-line four-cylinder internal combustion engine (hereinafter simply referred to as engine 1c) equipped with a SOHC type valve train MV1. The valve train MV1 of the engine 1c is a cylinder head 2c.
A cam shaft 5c provided therein, a support base 11c arranged above the cam shaft, and intake side and exhaust side fulcrum shafts 12 and 13 arranged near both sides of the support base 11c. Are arranged opposite to each other in parallel. Support 11c
Has a long frame shape, and the left and right upper side plates 111c and 112c and the left and right hanging plates 114c and 11 are provided between the front and rear column portions 113.
5c, the front and rear column parts 113 are bolted to the lower wall in the cylinder head 2c.

The camshaft 5c is connected to the crankshaft side (not shown) through a timing sprocket and a timing belt (not shown), so that the rotation of the engine 1
It is configured to rotate the cam shaft at a rotation speed of / 2. Here, the cam shaft 5c is alternately provided with intake / exhaust cams 7c, 8c for opening and closing the intake valve 3 and the exhaust valve 4 at positions opposed to each cylinder, and the intake / exhaust cams 7c, 8c are provided with the intake valve 3 via swing members 9, 10. And to apply a pressing force to the valve stem of the exhaust valve 4. Here, each rocking member 9 and 10 is formed with a sliding end 901 (the center end side of the rocking member 9 is not shown) and sliding ends 101 and 102, which respectively pivotally support the roller 17 and each spring bearing. 905 and 105 are formed, the cam member contact side surfaces 903 and 103, and the engine valve side contact surface 904.
104 are formed respectively. Each spring receiver 905, 10
5, between the left and right upper side plates 111c, 112c, the spring 20,
20 are installed respectively.

Sliding ends 901, 101 of the rocking members 9, 10
Is held by the guide pieces 21 and 22 of the cylinder head 2c so as to be vertically slidable. Sliding end 102 of swing members 9 and 10
(The swinging member 9 side is not shown) is vertically slidably held in the guide grooves 23c and 24c of the support base 11c in a state in which lateral displacement is restricted. Here, the guide grooves 23c and 24c are sequentially formed in a vertical slit shape at the lower ends of the hanging plates 114c and 115c of the support base 11c. The cam member contact side surfaces 903, 103 of the swinging members 9, 10 are formed by an arc having a radius centered on the center points Oi, Oe of the cam members 18, 19. The center point Oi of the cam member 18 coincides with the center point of the intake side fulcrum shaft 12 and is arranged on the valve axis of the intake valve 3. Similarly, the center point Oe of the cam member 19 coincides with the center point of the exhaust side fulcrum shaft 13 and is arranged on the valve axis of the exhaust valve 4.

The intake-side and exhaust-side fulcrum shafts 12 and 13 are composed of center shafts 121 and 131 and outer shafts 122 and 132, respectively. The center shafts 121 and 131 are integrally mounted with the cam members 18 and 19 for the second and third cylinders, respectively, and are rotatably operated by the step motor M1.
2, the cam members 18 and 19 of the first and fourth cylinders are integrally attached, and are rotated by a step motor M2 (see FIG. 2) to pass through openings 123 and 133 from the inside to the center shafts 121 and 131 side. 2, each cam member 1 for the third cylinder
8, 19 are projected and deployed. Step motor M1, M
2 is connected to an ECU 30 as a step number control means. Since the ECU 30 is controlled and operated in the same manner as that of the first embodiment, duplicated explanation is omitted.

The valve drive system of the second embodiment is also the first embodiment.
It is possible to install a valve drive device capable of selectively switching between a high-speed operation range, a low-speed operation range, and a cylinder deactivation operation range in the engine 1c of a single camshaft 5c. There is an advantage that the cost can be reduced. In the above, the valve drive device is a series 4
Although the internal combustion engine of the cylinder is equipped, the V-type engine (not shown) may be equipped with a valve drive device instead. In this case, each cylinder of one V bank of a V-type engine (not shown) is connected to the low-high speed positions A1 and A2 and the cylinder deactivation position A3.
(See FIG. 1), and the arrangement configuration in which each cylinder of the other V bank can be switched only to the low and high speed positions A1 and A2 can be adopted. As a result, each bank can have a relatively simplified configuration in which each fulcrum support shaft on the intake and exhaust sides and two step motors that drive the fulcrum support shafts are provided, and the layout of the valve drive device is simplified. To be done.

[0038]

As described above, according to the first aspect of the present invention, in order to secure the valve lift amount according to the operating range of the engine, the fulcrum support control means makes the center of rotation of the swing member continuous. Since it is changed to, it is possible to smoothly switch the valve lift amount continuously. According to the second aspect of the invention, in particular, since the center of rotation of the swinging member is continuously changed by the cam member included in the fulcrum support control means, the valve lift amount can be smoothly switched continuously, and the valve can be smoothly changed. Lift amount stabilizes. According to the third aspect of the invention, in particular, since the swing member is swung by being guided by the notch, continuous switching of the valve lift amount can be smoothly performed, and the swing member can be reliably operated. be able to.

According to the fourth aspect of the present invention, in particular, since the cam member abuts on the rocking member at a portion located on the axis of the engine valve, continuous switching of the valve lift amount can be smoothly performed. The valve can be stopped. According to the invention of claim 5, in particular, since the fulcrum support control means includes a plurality of shafts provided with cam members and an actuator for rotating each shaft, the operation mode of the engine valve is made different, A device capable of smoothly switching the valve lift amount continuously can be reliably provided. According to the invention of claim 6, in particular, since a plurality of shafts are coaxially arranged and an actuator is arranged at the end of the shafts, continuous switching of the valve lift amount can be smoothly performed. The layout for mounting the engine on the device can be facilitated.

According to the invention of claim 7, in particular, the engine valve of one bank of the V-type engine is stopped so that a device for smoothly switching the valve lift amount continuously is mounted. , V-type engine mounting layout can be facilitated. According to the invention of claim 8, in particular, the cam member controls the switching of the rotation angle of the rocking member according to the engine speed and the accelerator pedal depression amount, so that the valve lift amount of the engine valve can be adjusted according to the operating range information. Smooth continuous switching. According to the invention of claim 9, in particular, since the cam member contacting side surface of the swinging member is formed by an arc having a radius centered on the cam member center point, the cam member smoothly moves on the cam member contacting side surface. Can be slid on
It is possible to smoothly switch the valve lift amount continuously.

According to the tenth aspect of the invention, in particular, the contact surface of the rocking member on the engine valve side is formed by an arc having a radius centered on the point of contact with the rocking member on the engine valve shaft. Therefore, there is no fluctuation in the valve lift amount when the engine valve side contact surface and the engine valve shaft are in contact after switching the valve lift amount,
The abutment surface on the engine valve side and the engine valve shaft can operate stably.
According to the invention of claim 11, in particular, since the rocking member contacts the cam via the roller, uneven wear of the device capable of smoothly switching the valve lift amount is prevented,
The durability can be improved.

[Brief description of drawings]

FIG. 1 is a sectional view of a valve drive device as a first embodiment of the present invention.

2 is a partially cutaway plan view of a valve train of an engine equipped with the valve drive system of FIG. 1. FIG.

3 is a characteristic diagram of an operating range setting map of an engine equipped with the valve drive system of FIG. 1. FIG.

FIG. 4 is a characteristic diagram of a step number calculation map corresponding to a cam member position used in an engine equipped with the valve drive system of FIG. 1, (a) for two and three cylinders, and (b) for 1, Four
For cylinders.

5 is a valve lift amount characteristic diagram of an intake valve and an exhaust valve equipped in the valve drive system of FIG. 1, (a) in a low speed operation range, (b) in a high speed operation range, c) shows each characteristic in the cylinder deactivation operation range.

6 is a flowchart of an operating range switching subroutine that is performed in an engine equipped with the valve drive system of FIG.

FIG. 7 is a partially cutaway plan view of a valve drive device as a first modification of the first embodiment.

FIG. 8 is a partially cutaway cross section of a valve drive device as a second modification of the first embodiment.

9 is a valve lift amount characteristic diagram of intake valves and exhaust valves equipped in the valve drive system of FIG. 8, (a) in a low speed operation range, (b) in a high speed operation range, c) shows each characteristic in the cylinder deactivation operation range.

FIG. 10 is a cross-sectional view of a valve drive device according to a second embodiment.

FIG. 11 is a partial perspective view of a conventional valve drive device.

12 is a cross-sectional view taken along the line AA of the valve drive device of FIG.

[Explanation of symbols]

 1 engine 2 cylinder head 3 intake valve 4 exhaust valve 7 cam 8 cam 7c cam 8c cam 9 rocking member 9b rocking member 901 sliding end 902 sliding end 101 sliding end 102 sliding end 903 cam member contacting side surface 903b Cam member contact side surface 103 Cam member contact side surface 10 Swing member 12 Support point support shaft 13 Support point support shaft 12a Support point support shaft 13a Support point support shaft 18 Cam member 19 Cam member 20 Spring 21 Guide piece 22 Guide piece 23 Guide groove 24 Guide Groove 30 Engine control unit (ECU) a1 Low speed operation range a2 High speed operation range a3 Cylinder deactivation area A1 Low speed position A2 High speed position A3 Cylinder deactivation position Ne Engine speed θa Load signal Ri Air intake path Re Exhaust path Oi Center point of cam member Oe cam member center point t clearance

Claims (11)

[Claims] Claim: What is claimed is: 1. An engine valve consisting of intake and exhaust valves, one end of which is pressed by a cam by a biasing amount of a spring, the other end drives the engine valve, and both ends of the engine body can swing. A valve drive device comprising: a supported swing member; and a fulcrum support control means for changing a rotation center of the swing member. 2. The valve drive device according to claim 1, wherein the fulcrum support control means includes a cam member that abuts on a center of rotation of the swing member. 3. The valve drive device according to claim 1, wherein the swinging member is swung by being guided by a notch provided in the casing. 4. The valve drive device according to claim 2, wherein the cam member abuts a portion on the swing member on the axis of the engine valve to stop the valve. 5. The fulcrum support control means comprises a plurality of shafts each provided with the cam member, and an actuator for rotating each shaft, and the operating mode of the engine valve is different. The valve drive device described. 6. The valve drive apparatus according to claim 5, wherein the plurality of shafts are coaxially arranged, and the actuator is arranged at an end portion of the shafts. 7. The valve drive system according to claim 4, wherein the engine valves are provided in V banks of a V-type engine, and the engine valves of one bank are stopped. 8. A valve drive system according to claim 4, wherein said cam member controls switching of a rotation angle of said rocking member depending on an engine speed and an accelerator pedal depression amount. 9. The valve drive device according to claim 2, wherein the cam member contacting side surface of the swing member is formed as an arc having a radius centered on the cam member center point. 10. The engine valve side contact surface of the swing member is formed with an arc having a radius centered on a point where the cam member contacts the swing member on the engine valve shaft. 10. The valve drive device according to item 10. 11. The valve drive device according to claim 1, wherein the swing member abuts on the cam via a roller.