JP2006070742A - Variable valve system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To mechanically change a valve characteristic, while restraining an increase in inertial mass of a movable part, in a variable valve system. <P>SOLUTION: A control cam 134 is fixed to a control shaft 132. Intermediate members 162 and 164 for transmitting driving force to a rocking member 150 from a driving cam 122, are sandwiched and supported from three directions by a cam surface of this control cam 134, a slide surface 156 of a rocking member 150 and a cam surface 124 of a driving cam 122. A position on the slide surface 156 of the intermediate members 162 and 164 and a position on the cam surface 124 of the driving cam 122, are interlocked and changed by rotating the control cam 134. Thus, the opening characteristic of a valve 104 is mechanically changed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a variable valve operating apparatus for an internal combustion engine, and more particularly to a variable valve operating apparatus capable of mechanically changing a valve opening characteristic of a valve.

  2. Description of the Related Art Conventionally, as disclosed in, for example, Patent Document 1, there is known a variable valve operating apparatus that mechanically changes a valve lift amount and valve timing in accordance with an engine operating state. In the variable valve operating apparatus described in Patent Document 1, a guide arm is fixed to a control shaft provided in parallel with a cam shaft, and one end of a follower is swingably attached to the guide arm. A swing cam is swingably attached to the control shaft, and a rocker arm is pressed against the swing cam surface. A first roller and a second roller, which can rotate independently of each other, are concentrically attached to the follower, the first roller contacts the valve cam of the camshaft, and the second roller is in contact with the swing cam surface of the swing cam. Is in contact with the contact surface formed on the opposite side.

According to such a configuration, the rotation position of the guide arm is changed by the rotation of the control shaft, so that the follower is displaced and the distance from the control shaft to the contact point between the swing cam and the second roller is changed. Thus, the lift amount of the valve is changed. Further, when the circumferential position of the valve cam that contacts the first roller changes at the same rotational angle position of the cam shaft, the valve timing is also changed at the same time. That is, according to the variable valve operating apparatus described in Patent Document 1, the lift amount of the valve and the valve timing can be changed simultaneously by controlling the rotation angle of the control shaft by the motor.
JP 2003-239712 A JP-A-7-63023

  By the way, in a valve operating apparatus, reduction of the inertial mass of the movable part movable at the time of a lift movement is calculated | required, in order to enable high speed rotation of an internal combustion engine. By reducing the inertial mass of the movable part, it is possible to reduce the spring force of the valve spring and reduce the friction, thereby improving the fuel consumption for driving the valve operating device. In the case of a variable valve operating device as described in Patent Document 1, a mechanism for mechanically changing the valve opening characteristics of the valve is newly added, so that compared with a normal valve operating device. The number of moving parts increases. Increasing the number of moving parts increases the inertial mass of the entire moving part. However, as described above, to increase the inertial mass of the moving part as much as possible in order to increase the internal combustion engine speed and improve fuel efficiency. Want to suppress.

  The present invention has been made to solve the above-described problems, and provides a variable valve operating device that can mechanically change the valve opening characteristics of the valve while suppressing an increase in the inertial mass of the movable part. The purpose is to do.

In order to achieve the above object, a first invention is a variable valve operating device that mechanically changes a valve opening characteristic with respect to rotation of a camshaft.
A drive cam provided on the camshaft;
A control shaft provided in parallel with the cam shaft and capable of changing the rotation angle continuously or in multiple stages;
A control cam fixed to the control shaft and rotating together with the control shaft;
A swing member that swings about an axis parallel to the cam shaft;
A rocking cam surface that is formed on the rocking member and contacts the valve support member that supports the valve to press the valve in the lift direction;
A slide surface formed on the swing member so as to face the drive cam;
An intermediate member that transmits a driving force from the driving cam to the swing member;
The intermediate member is sandwiched and supported from three directions by the cam surface of the drive cam, the slide surface, and the cam surface of the control cam.

  According to a second aspect, in the first aspect, the intermediate member is a first roller that contacts the cam surface of the drive cam, and a second roller that is disposed concentrically with the first roller and contacts the slide surface. It includes a roller and a connecting shaft that connects the first roller and the second roller so as to be independently rotatable.

  According to a third invention, in the first or second invention, the control cam is configured as a disk centered at a position eccentric from the control shaft, and a rotatable rotating surface is provided on an outer peripheral surface of the disk. It is characterized by being attached.

  According to a fourth invention, in any one of the first to third inventions, the swinging member is rotatably attached to the control shaft and swings about the control shaft. .

  In a fifth aspect based on the fourth aspect, the slide surface is curved toward the drive cam, and the distance from the center of the cam shaft increases as the distance from the swing center of the swing member increases. It is characterized by being formed to be small.

In a sixth aspect based on the fifth aspect, the rocking cam surface is provided continuously with the non-working surface having a constant distance from the rocking center of the rocking member and the non-working surface. A working surface formed such that the distance from the swing center gradually increases as the distance from the non-working surface increases.
As the swing member swings, the position of the swing cam surface in contact with the valve support member moves from the non-working surface to the working surface, whereby the valve is lifted.

  According to a seventh aspect, in the sixth aspect, the intermediate member contacts the intermediate member at the same rotation angle of the cam shaft as the position of the intermediate member on the slide surface is further away from the swing center of the swing member. The circumferential position of the drive cam is moved to the retard side of the cam shaft.

  When the cam shaft rotates in the first invention, the rotational motion is transmitted from the cam surface of the drive cam to the slide surface of the swing member via the intermediate member, and is converted into the swing motion of the swing member. The intermediate member is sandwiched and supported from three directions by the cam surface of the drive cam, the slide surface of the swinging member, and the cam surface of the control cam, and moves by itself. Therefore, according to the first aspect of the invention, only the swing member and the intermediate member are movable during the lift movement of the valve, and the inertia of the entire movable portion with respect to the normal valve operating apparatus that directly drives the valve support member by the drive cam. The increase in mass is suppressed.

  Further, when the control shaft rotates in the first invention, the control cam fixed to the control shaft also rotates around the control shaft. Since the intermediate member is sandwiched and supported by the cam surface of the drive cam, the slide surface of the swing member, and the cam surface of the control cam from the three directions, the control cam rotates and moves on the control cam surface of the intermediate member. As the position changes, the position of the intermediate member on the drive cam surface and the position on the slide surface also change at the same time. By changing the position of the intermediate member on the slide surface, the swing angle width and the initial swing angle of the swing member change, and the lift amount of the valve changes. Further, when the position of the intermediate member on the drive cam surface is changed, the swing timing of the swing member with respect to the phase of the cam shaft is changed, and the valve timing is changed. Thus, according to the first aspect, the valve opening characteristic of the valve can be mechanically changed by controlling the rotation angle of the control shaft.

  According to the second aspect of the present invention, the intermediate member has two rollers that can rotate independently. One of the first rollers is in contact with the drive cam surface, and the other second roller is in contact with the slide surface. Therefore, the friction loss in the transmission path of the driving force from the driving cam to the swinging member can be reduced, and the deterioration of fuel consumption can be prevented.

  According to the third aspect of the invention, since the rotatable rotating surface becomes the cam surface of the control cam, it is possible to reduce the friction loss between the control cam and the intermediate member and prevent the deterioration of the fuel consumption.

  According to the fourth aspect, since the control shaft is also used as the shaft of the swing member, the structure can be simplified and the rigidity can be increased.

  According to the fifth aspect, regardless of the position of the intermediate member on the slide surface, the intermediate member is securely sandwiched from the three directions by the cam surface of the drive cam, the slide surface of the swing member, and the cam surface of the control cam. Can be held in. Further, the slide surface is formed so that the distance from the center of the cam shaft becomes smaller as the distance from the swing center of the swing member becomes larger, so that the intermediate member swings as it goes to the tip of the slide surface. The initial swing angle of the member can be increased.

  According to the sixth aspect of the invention, the lift amount is determined by the arrival position of the valve support member on the operating surface, and the operating angle is determined by the period during which the valve support member is positioned on the operating surface. As described above, when the initial swing angle of the swing member increases, the arrival position of the valve support member on the action surface moves to the tip side of the slide surface, and the valve support member moves on the action surface accordingly. The period of time at is also longer. Therefore, according to the sixth aspect of the invention, the lift amount and the operating angle can be increased in conjunction with the intermediate member as it goes to the tip of the slide surface.

  Further, when the circumferential position of the drive cam that contacts the intermediate member at the same rotation angle of the cam shaft moves to the retard side of the cam shaft, the valve timing is retarded by delaying the swing timing of the swing member. According to the seventh aspect of the invention, the valve timing is retarded as the intermediate member goes to the tip of the slide surface. Therefore, the valve opening characteristic is such that the valve timing is retarded as the lift amount and the working angle increase. Can be realized.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

[Configuration of Variable Valve Operating Device of this Embodiment]
FIG. 1 is a perspective view showing a configuration of a variable valve apparatus 100 according to an embodiment of the present invention. The variable valve operating apparatus 100 has a rocker arm type mechanical valve operating mechanism, and the rotational movement of the camshaft 120 is caused by the drive cam 122 provided on the camshaft 120 to swing the rocker arm (valve support member) 110. And converted into a lift motion of the valve 104 supported by the rocker arm 110. The drive cam 122 has two cam surfaces 124a and 124b having different profiles. The non-working surface 124a, which is one cam surface, is a peripheral surface of the cam base circle, and is formed at a constant distance from the center of the cam shaft 120. The working surface 124b, which is the other cam surface, is formed such that the distance from the center of the camshaft 120 gradually increases and gradually decreases after passing the top. In the present specification, when the non-working surface 124a and the working surface 124b are not distinguished from each other, they are simply referred to as the drive cam surface 124.

  In the variable valve operating apparatus 100, the rocker arm 110 is not directly driven by the drive cam 122, but the variable mechanism 130 is interposed between the drive cam 122 and the rocker arm 110. The variable mechanism 130 is a mechanism that can continuously change the interlocking state between the rotational motion of the drive cam 122 and the rocking motion of the rocker arm 110. The variable valve operating device 100 can change the lift amount and valve timing of the valve 104 continuously by changing the swing amount and swing timing of the rocker arm 110 by variably controlling the variable mechanism 130. ing.

  As will be described below, the variable mechanism 130 includes a control shaft 132, a control cam 134, a swing cam arm 150, a first roller 162, a second roller 164, and a connection that connects the first roller 162 and the second roller 164. The shaft 166 is configured as a main component member. The control shaft 132 is an axis parallel to the cam shaft 120 and is disposed at a position relative to the cam shaft 120 at a position upstream of the rocker arm 110 in the rotational direction of the cam shaft 120. An actuator (for example, a motor) (not shown) is connected to the control shaft 132, and the ECU of the internal combustion engine can adjust the rotation angle of the control shaft 132 to an arbitrary angle by controlling the actuator.

  A control cam 134 is integrally fixed to the control shaft 132. The control cam 134 has a flat disk shape, and its center is eccentric from the center of the control shaft 132. A cylindrical rotating surface 136 is attached to the outer peripheral surface of the control cam 134. A bearing (not shown) is interposed between the rotation surface 136 and the control cam 134 so that the rotation surface 136 can freely rotate around the control cam 134.

  The control cam 134 is disposed in the plane on which the drive cam 122 is rotating. A first roller 162 is disposed between the control cam 134 and the drive cam 122, and the first roller 162 is in contact with both the rotation surface 136 and the drive cam surface 124. On both sides of the first roller 162, a second roller 164 having a smaller diameter than the first roller 162 is disposed concentrically with the first roller 162. The first roller 162 and the second roller 164 are connected to each other by a connecting shaft 166 so as to be independently rotatable. A slide surface 156 of a swing cam arm 150 described later is in contact with the second roller 164. The intermediate member composed of the first roller 162, the second roller 164, and the connecting shaft 166 is sandwiched in three directions by the rotation surface 136, the drive cam surfaces 124 (124 a and 124 b) of the drive cam 122, and the slide surface 156. Positioned in space.

  The swing cam arm 150 is supported by the control shaft 132 so as to be swingable, and the tip thereof is disposed toward the downstream side in the rotation direction of the drive cam 122. On the side of the swing cam arm 150 facing the drive cam 122, a slide surface 156 that is curved toward the drive cam surface 122 is formed. As described above, the slide surface 156 contacts the second roller 164, and holds the first roller 162 and the second roller 164 together with the drive cam surface 124 and the rotation surface 136 from three directions. For this reason, even when the slide surface 156 is opened to the maximum (see FIG. 2B), the first roller 162 and the second roller 164 do not come out of the gap between the drive cam surface 124 and the slide surface 156. The slide surface 156 is formed such that the distance from the cam basic circle (non-operation surface 124a) of the drive cam 122 decreases as the distance from the center of the control shaft 132, which is the center of oscillation, increases.

  On the other hand, a swing cam surface 152 (152a, 152b) is formed on the surface of the swing cam arm 150 opposite to the slide surface 156. The swing cam surface 152 is a cam surface having the swing center of the swing cam arm 150 as the cam center, and is composed of a non-working surface 152a and a working surface 152b having different profiles. Among them, the non-operation surface 152a is a circumferential surface of the cam base circle, and is formed with a constant distance from the center of the control shaft 132. The other working surface 152b is provided on the distal end side of the swinging cam arm 150 when viewed from the non-working surface 152a, and is connected to the non-working surface 152a so as to be smoothly continuous, and at the distal end of the swinging cam arm 150. The distance from the center of the control shaft 132 (that is, the cam height) is gradually increased. In this specification, when not distinguishing both the non-operation surface 152a and the operation surface 152b, it will only be described as the swing cam surface 152.

  The swing cam arm 150 is formed with a spring seat surface (see FIG. 2) 158 for applying a lost motion spring (not shown). The spring seat surface 158 is formed on the side opposite to the operation surface 156b with respect to the non-operation surface 152a. The lost motion spring is a compression spring, and the other end is fixed to a stationary member (not shown). The urging force from the lost motion spring acts as an urging force that presses the slide surface 156 against the second roller 164 via the swing cam arm 150, and further causes the first roller 162 to act on the drive cam surface 124 via the connecting shaft 166. And acts as a biasing force against the rotating surface 136. Accordingly, the first roller 162 and the second roller 164 are positioned by being sandwiched from three directions by the slide surface 156, the drive cam surface 124, and the rotation surface 136.

  The variable valve operating apparatus 100 employs a one-cam two-valve drive structure in which two valves 104 are driven by one drive cam 122. For this reason, a pair of swing cam arms 150 are arranged on both sides of the control cam 136. A rocker arm 110 is disposed below each swing cam arm 150. A rocker roller 112 is disposed on the rocker arm 110 so as to face the swing cam surface 152. The rocker roller 112 is rotatably attached to an intermediate portion of the rocker arm 110. A valve shaft 102 that supports the valve 104 is attached to one end of the rocker arm 110, and the other end of the rocker arm 110 is rotatably supported by a hydraulic lash adjuster 106. The valve shaft 102 is positioned by a valve spring (not shown), and the rocker roller 112 is pressed against the swing cam surface 152 by the rocker arm 110 being pushed up by the hydraulic lash adjuster 106.

[Operation of Variable Valve Operating Device of this Embodiment]
Next, the operation of the variable valve apparatus 100 will be described with reference to FIGS.

(1) Lifting Operation of Variable Valve Operating Device First, the lifting operation of the variable valve operating device 100 will be described with reference to FIG. In the figure, (A) shows the state of the variable valve apparatus 100 when the valve 104 (see FIG. 1, omitted in FIG. 2) is closed during the lift operation, and (B) shows the lift operation. The state of the variable valve operating apparatus 100 when the valve 104 is opened in the process is shown.

  In the variable valve apparatus 100, the rotational motion of the drive cam 122 is first input to the first roller 162 that contacts the drive cam surface 124. The first roller 162 moves along the surface of the control cam 134 together with the second roller 164 provided coaxially, and the movement is input to the slide surface 156 of the swing cam arm 150 supporting the second roller 164. The Since the slide surface 156 is always pressed against the second roller 164 by the biasing force of the lost motion spring (not shown), the swing cam arm 150 swings about the control shaft 132 according to the rotation of the drive cam 122. To do.

  Specifically, when the camshaft 120 rotates from the state shown in FIG. 2A, the contact position P1 on the drive cam surface 124 of the first roller 162 is not set as shown in FIG. The working surface 124a moves to the working surface 124b. The first roller 162 is relatively pushed down along the surface of the control cam 134 by the drive cam 122, and the swing cam arm 150 is pushed down the slide surface 156 by the second roller 164 integrated with the first roller 162. As a result, the swing cam arm 150 rotates in the clockwise direction in the drawing around the control shaft 132. When the cam shaft 120 further rotates and the contact position P1 of the first roller 162 on the drive cam surface 124 passes the top of the working surface 124b, the swing cam arm 150 is now driven by the urging force of the lost motion spring and the valve spring. Rotates about the control shaft 132 in the counterclockwise direction in the figure.

  As the swing cam arm 150 rotates around the control shaft 132 in this way, the contact position P3 of the rocker roller 112 on the swing cam surface 152 changes. In the drawing, the contact positions on the rocking cam surface 152 of the rocker roller 112 are indicated as P3i and P3f. This is for distinguishing between an initial contact position P3i and a final contact position P3f, which will be described later. is there. In this specification, when the contact position on the rocking cam surface 152 of the rocker roller 112 is simply indicated, it is expressed as a contact position P3.

  As shown in FIG. 2A, when the rocker roller 112 is in contact with the non-operation surface 152a, the non-operation surface 152a has a constant distance from the center of the control shaft 132. Regardless, the position of the rocker roller 112 in the space does not change. Therefore, the rocker arm 110 does not swing and the valve 104 is held at a fixed position. In the variable valve operating apparatus 100, the positional relationship of each part is adjusted so that the valve 104 is closed when the rocker roller 112 is in contact with the non-operation surface 152a.

  Then, as shown in FIG. 2B, when the contact position P3 of the rocker roller 112 on the swing cam surface 152 is switched from the non-operation surface 152a to the operation surface 152b, the rocker arm 110 is moved to the operation surface 152b. It is pushed down according to the distance from the center of the control shaft 132 and swings clockwise around a support point by the hydraulic lash adjuster 106. As a result, the valve 104 is pushed down by the rocker arm 110 and opened.

(2) Lift amount changing operation of variable valve operating apparatus Next, the lift amount changing operation of the variable valve operating apparatus 100 will be described with reference to FIGS. Here, FIG. 3 shows a state in which the variable valve apparatus 100 is operating so as to give a small lift to the valve 104 (see FIG. 1, omitted in FIG. 3). On the other hand, FIG. 2 described above shows a state in which the variable valve apparatus 100 is operated so as to give a large lift to the valve 104. In each figure, (A) shows the state of the variable valve apparatus 100 when the valve 104 is closed during the lift operation, and (B) shows the valve 104 opened during the lift operation. The state of the variable valve operating apparatus 100 when the vehicle is in operation is shown.

  When the lift amount is changed from the lift amount shown in FIG. 2 to the lift amount shown in FIG. 3, the control shaft 132 is rotationally driven in the state shown in FIG. 2A and controlled to the position shown in FIG. The center C1 of the cam 134 is rotationally moved. The first roller 162 is always pressed against the rotating surface 136 of the control cam 134, so that the first roller 162 is held at a constant distance from the center C <b> 1 of the control cam 134. Therefore, as the center C1 of the control cam 134 moves, the first roller 162 moves along the drive cam surface 124 from the position shown in FIG. 2A to the position shown in FIG. At the same time, the second roller 164 moves along the slide surface 156 in a direction approaching the control shaft 132 that is the swing center of the swing cam arm 150.

  Although there is a speed difference between the drive cam surface 124 and the slide surface 156, the first roller 162 in contact with the drive cam surface 124 and the second roller 164 in contact with the slide surface 156 can rotate independently. There is no friction loss due to the speed difference on the slide surface 156. Further, the rotation surface 136 is in contact with the first roller 162 together with the drive cam surface 124, but the rotation surface 136 is rotatably supported by the control cam 134, so the rotation surface 136 together with the first roller 162 is the drive cam surface 124. Can follow the rotation. Therefore, friction loss on the surfaces of the drive cam surface 124 and the rotating surface 136 is also reduced.

  When the second roller 164 moves on the slide surface 156 in a direction approaching the control shaft 132, the distance from the swing center C0 of the swing cam arm 150 to the contact position P2 on the slide surface 156 of the second roller 164 is increased. As a result, the swing angle of the swing cam arm 150 increases. This is because the swing angle width of the swing cam arm 150 is inversely proportional to the distance from the swing center C0 to the contact position P2, which is the input point of vibration. The lift of the valve 104 is maximum when the contact position P1 of the first roller 162 on the drive cam surface 124 is at the top of the working surface 124b, as shown in FIG. The lift amount of the valve 104 is determined by the contact position P3f (hereinafter referred to as the final contact position) on the swing cam surface 152 of 112. FIG. 4 is a diagram showing the relationship between the position of the rocker roller 112 on the swing cam surface 152 and the valve lift. As shown in this figure, the final contact position P3f includes the swing angle width of the swing cam arm 150 and the contact position P3i on the swing cam surface 152 of the rocker roller 112 shown in FIG. Initial contact position).

  The initial contact position P3i changes depending on the inclination angle of the swing cam arm 150 when the first roller 162 is in contact with the non-operation surface 124a of the drive cam 122. In the variable valve operating apparatus 100 of the present embodiment, the distance between the slide surface 156 and the cam base circle of the drive cam 120 is set to be farther away as the position is closer to the control shaft 132. For this reason, as the second roller 164 moves on the slide surface 156 in a direction approaching the control shaft 132, the slide surface 156 is pushed up by the urging force of the lost motion spring. As a result, the swing cam arm 150 rotates around the control shaft 132 in the counterclockwise direction in the drawing, and the initial contact position P3i changes in a direction away from the action surface 152b.

  If the initial contact position P3i is constant, the final contact position P3f moves to the distal end side of the working surface 152b as the swing angle width of the swing cam arm 150 increases. If the swing angle width of the swing cam arm 150 is constant, the final contact position P3f moves to the non-working surface 152a side by moving the initial contact position P3i away from the working surface 152b. In the variable valve apparatus 100 of the present embodiment, as shown in FIG. 4, the effect of the movement of the initial contact position P3i exceeds the effect of the increase of the swing angle width, and the final contact position P3f moves to the non-working surface 152a side. To do. As a result, the lift amount of the valve 104 decreases. The period during which the rocker roller 112 is positioned on the working surface 152a (crank angle) is the working angle of the valve 104, but the final contact position P3f moves to the non-working surface 152a side. The working angle is also reduced.

  At the same time, the first roller 162 moves on the slide surface 156 in a direction approaching the control shaft 132, so that the contact of the first roller 162 on the drive cam surface 124 when the cam shaft 120 is at the same rotation angle. The position P1 moves to the advance side of the drive cam 122. As a result, the swing timing of the swing cam arm 150 with respect to the phase of the cam shaft 120 is advanced, and as a result, the valve timing (maximum lift timing) is advanced.

  FIG. 5 is a graph showing the relationship between the lift amount of the valve 104 and the valve timing realized by the variable valve apparatus 100. As shown in this figure, according to the variable valve apparatus 100, the operating angle can be increased and the valve timing can be retarded in conjunction with the increase in the lift amount of the valve 104. In conjunction with the decrease in the amount, the operating angle can be decreased and the valve timing can be advanced. Therefore, for example, when the valve 104 is an intake valve, the valve opening characteristic can be variably controlled so that the opening timing of the valve 104 is substantially constant without using a valve timing control mechanism such as VVT.

[Advantages of the variable valve operating apparatus of this embodiment]
As described above, according to the variable valve operating apparatus 100 of the present embodiment, the contact position of the second roller 164 on the slide surface by rotating the control shaft 132 and changing the rotation angle of the control cam 134. The contact position P1 of P2 and the first roller 162 on the drive cam surface 124 is changed, and as a result, the lift amount, the operating angle, and the valve timing of the valve 104 can be changed in conjunction with each other. Moreover, the rollers 162 and 164 are sandwiched and supported from three directions by the drive cam surface 124, the slide surface 156, and the rotating surface 136 of the control cam 134, and move by themselves. Therefore, only the intermediate member composed of the rollers 162 and 164 and the connecting shaft 166 other than the swing cam arm 150 is movable during the lift movement of the valve 104, and the inertial mass of the entire movable portion relative to the normal valve operating device is increased. The increase is suppressed. Therefore, according to the variable valve operating apparatus 100 of the present embodiment, the friction of the valve spring can be reduced by reducing the spring force of the valve spring, and the fuel consumption for driving the valve operating apparatus can be improved.

[Others]
Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. For example, the following modifications may be made.

  In the embodiment described above, a disk centered on a position eccentric from the control shaft 132 is used as the control cam 134, but the cam height of the portion where the first roller 162 is in contact with the rotation of the control shaft 132 is used. If it changes, it will not be limited to the structure of the said embodiment.

  In the above-described embodiment, the swing cam arm 150 is attached to the control shaft 132, but the shaft of the swing cam arm 150 and the control shaft 132 may be separate axes.

  In the above embodiment, the control cam 134 supports the first roller 162 together with the drive cam 122. However, a third roller is provided coaxially separately from the first roller 162 and the second roller 164. The third roller may be supported by the control cam 134.

  In the above embodiment, two valves are driven by one drive cam, but only one valve may be driven. In the above embodiment, the present invention is applied to a rocker arm type valve operating device, but it can also be applied to other types of valve operating devices such as a direct acting type.

It is a perspective view which shows the structure of the variable valve apparatus concerning embodiment of this invention. It is a figure which shows operation | movement of the variable valve apparatus at the time of a big lift, (A) has shown the valve closing time, (B) has shown the valve opening time. It is a figure which shows operation | movement of the variable valve operating apparatus at the time of a small lift, (A) has shown the valve closing time, (B) has shown the valve opening time. It is a figure which shows the relationship between the position on the rocking cam surface of a rocker roller, and the lift amount of a valve | bulb. It is a figure which shows the relationship between valve timing and lift amount.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Variable valve apparatus 104 Valve 110 Rocker arm 112 Rocker roller 120 Cam shaft 122 Drive cam 124 (124a, 124b) Drive cam surface 130 Variable mechanism 132 Control shaft 134 Control cam 136 Rotating surface 150 Oscillating cam arm 152 (152a, 152b) Swing cam surface 156 Slide surface 162 First roller 164 Second roller 166 Connecting shaft P1 Contact position P2 on the driving cam surface of the first roller P2 Contact position P3i on the slide surface of the second roller Rocker cam swing cam Initial contact position P3f on the surface Final contact position on the rocking cam surface of the rocker roller

Claims (7)

A variable valve operating device that mechanically changes a valve opening characteristic with respect to rotation of a camshaft,
A drive cam provided on the camshaft;
A control shaft provided in parallel with the cam shaft and capable of changing the rotation angle continuously or in multiple stages;
A control cam fixed to the control shaft and rotating together with the control shaft;
A swing member that swings about an axis parallel to the cam shaft;
A rocking cam surface that is formed on the rocking member and contacts the valve support member that supports the valve to press the valve in the lift direction;
A slide surface formed on the swing member so as to face the drive cam;
An intermediate member that transmits a driving force from the driving cam to the swing member;
The variable valve operating apparatus, wherein the intermediate member is sandwiched and supported from three directions by the cam surface of the drive cam, the slide surface, and the cam surface of the control cam.   The intermediate member includes: a first roller that contacts the cam surface of the drive cam; a second roller that is disposed concentrically with the first roller and contacts the slide surface; the first roller and the second roller; The variable valve operating apparatus according to claim 1, further comprising a connecting shaft that connects the shafts so as to be independently rotatable.   The said control cam is comprised as a disk centering on the position eccentric from the said control axis | shaft, The rotating surface which can rotate freely is attached to the outer peripheral surface of the said disk. Variable valve gear.   4. The variable valve operating apparatus according to claim 1, wherein the swinging member is rotatably attached to the control shaft and swings about the control shaft. 5.   The slide surface is curved toward the drive cam and is formed such that the distance from the center of the cam shaft decreases as the distance from the swing center of the swing member increases. The variable valve operating apparatus according to claim 4. The rocking cam surface is provided continuously with the non-working surface with a constant distance from the rocking center of the rocking member, and the distance from the rocking center increases as the distance from the non-working surface increases. And a working surface formed to become gradually larger,
6. The valve is lifted by moving a position of contact of the rocking cam surface with the valve support member from the non-working surface to the working surface as the rocking member is swung. The variable valve operating device described. As the position of the intermediate member on the slide surface is further away from the swing center of the swing member, the circumferential position of the drive cam that contacts the intermediate member at the same rotation angle of the cam shaft is the position of the cam shaft. The variable valve operating apparatus according to claim 6, wherein the variable valve operating apparatus moves to the retard side.

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