JP2006070737A - Variable valve system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To highly accurately and variably control a valve opening characteristic of a valve, in a variable valve system. <P>SOLUTION: A rocking member 140 is rotatably installed on a camshaft 120. The rocking member 140 forms a sliding surface 156 and a rocking cam surface contacting with a valve support member 110 for supporting the valve 104. The sliding surface 156 is oppositely formed to the driving cam surface 124 of the camshaft 120, and intermediate members 170 and 172 are arranged between the sliding surface 156 and the driving cam surface 124. A control shaft 132 is arranged side by side with the camshaft 120. A position of the intermediate members 170 and 172 on the driving cam surface 124 when the camshaft 120 exists at the same turning angle, is changed by interlocking with rotation of a control shaft 132. <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 Special table 2003-500602 gazette JP 2004-108302 A JP-A-7-63023

  However, in the variable valve device described in Patent Document 1, there is a possibility that the inter-axis distance between the cam shaft and the control shaft may vary due to processing errors, thermal expansion, and the like. Since the swing cam that transmits the rotation of the cam shaft to the rocker arm is supported by the control shaft, the swing amount and swing timing of the swing cam change if the distance between the cam shaft and the control shaft varies. The lift amount and valve timing of the valve may be deviated from the desired lift amount and valve timing. Since the valve opening characteristics affect the output, fuel consumption, exhaust gas performance, etc. of the internal combustion engine, it is desirable to be able to variably control with high accuracy at all times while suppressing the effects of processing errors and thermal expansion as much as possible.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a variable valve operating apparatus that can variably control the valve opening characteristics of the valve with high accuracy.

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 swinging member rotatably attached to the camshaft and swinging about the camshaft;
A drive cam provided on the camshaft;
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 is disposed between the drive cam and the swing member and contacts both the cam surface and the slide surface of the drive cam;
A control shaft provided in parallel with the cam shaft and capable of changing the rotation angle continuously or in multiple stages;
An interlocking mechanism that changes the position of the intermediate member on the drive cam at the same rotation angle of the camshaft in conjunction with the rotation of the control shaft;
It is characterized by having.

  According to a second aspect, in the first aspect, the slide surface is curved toward the drive cam, and the distance from the center of the cam shaft gradually increases from one end to the other end. It is characterized by being formed as follows.

  According to a third invention, in the first or second invention, the interlocking mechanism is fixed to the control shaft and has a fulcrum at a position eccentric from the center of the control shaft, and can swing on the fulcrum. And a connecting member that connects the intermediate member to the control member.

According to a fourth invention, in any one of the first to third inventions, the rocking cam surface includes a non-working surface having a constant distance from the rocking center of the rocking member, and the non-working surface. A working surface that is continuously provided and formed such that the distance from the swing center gradually increases as the distance from the non-working surface increases.
The valve is lifted when the contact position of the valve support member with the rocking cam surface moves from the non-working surface to the working surface as the rocking member swings.

  According to a fifth invention, in any one of the first to fourth inventions, the intermediate member is disposed concentrically with the first roller that contacts the cam surface of the drive cam, and the slide. It is characterized by including the 2nd roller which contacts a surface, and the connecting shaft which connects the 1st roller and the 2nd roller so that rotation is possible independently.

  In the first invention, when the cam shaft rotates, the rotational motion is transmitted from the drive cam to the slide surface of the swing member via the intermediate member, and is converted into a swing motion around the cam shaft of the swing member. The swing characteristic of the swing member at this time is determined by the position of the intermediate member on the drive cam at the same rotation angle of the cam shaft. Specifically, when the intermediate member moves on the cam surface of the drive cam to the advance side, the swing timing of the swing member with respect to the phase of the cam shaft is advanced, and conversely when the intermediate member moves to the retard side, the cam shaft The swing timing of the swing member with respect to the phase is delayed. When the swing timing of the swing member changes, the valve timing of the valve that contacts the swing cam surface via the valve support member also changes. Further, when the position of the intermediate member on the drive cam at the same rotation angle of the cam shaft changes, the rotation angle around the cam shaft of the swinging member that is in contact with the intermediate member by the slide surface also changes. The change in the rotation angle of the swing member around the cam shaft changes the initial contact position of the valve support member on the swing cam surface. As a result, the range of movement of the valve support member on the rocking cam surface associated with the rocking of the rocking member changes, and the lift amount of the valve changes.

  According to the first aspect of the invention, the position of the intermediate member on the drive cam can be changed in conjunction with the rotation of the control shaft. Can be variably controlled in stages. In addition, since the swinging member that transmits the rotational movement of the camshaft to the valve is supported by the camshaft, the swinging member swings due to variations in the inter-shaft distance between the camshaft and the swinging member shaft. There is no deviation in the amount of movement or the swing timing. Therefore, according to the first invention, the valve opening characteristic of the valve can be variably controlled with high accuracy.

  According to the second invention, the slide surface is formed to be curved toward the drive cam surface side so that the distance from the center of the cam shaft gradually increases from one end portion to the other end portion. Thus, the valve can be operated with a smooth lift curve.

  In addition, when the control shaft rotates in the third invention, the rotation position of the control member fixed to the control shaft changes, so that the position on the slide surface of the intermediate member connected to the control member via the connection member Also changes. According to the third aspect, with such a simple configuration, the change in the position of the intermediate member on the slide surface can be reliably linked to the rotation of the control shaft.

  According to the fourth 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 contact position on the rocking cam surface of the valve support member changes, the arrival position on the operation surface of the valve support member changes, and the valve support member is positioned on the operation surface accordingly. The period during which it is changing also changes. Therefore, according to the fourth invention, the operating angle and the lift amount can be changed in conjunction with each other.

  According to the fifth 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 cam surface of the drive cam, and the other second roller is in contact with the slide surface. Therefore, the friction loss in the transmission system of the driving force from the camshaft to the valve can be reduced, and the deterioration of the fuel consumption can be prevented. Moreover, since the two rollers are arranged coaxially, the intermediate member is not only compact, but also the distance between the cam surface of the drive cam and the slide surface can be suppressed, and the entire variable valve system is compact. Can be configured.

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

[Configuration of Variable Valve Operating Device of this Embodiment]
FIGS. 1 to 3 are views showing the configuration of a variable valve operating apparatus 100 according to an embodiment of the present invention, FIG. 1 is a perspective view, and FIG. 2 is a side view of the AA cross section of FIG. FIG. 3 is a side view of the BB cross section of FIG. 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.

  The variable mechanism 130 swings on the control shaft 132, the eccentric shaft (control member) 166, the link arm (connection member) 164, the first roller 170, the second roller 172, and the cam shaft 120 as described below. A swing cam arm (swing member) 140 supported so as to be supported is configured as a main constituent member. The swing cam arm 140 includes a swing arm 154 and two swing cams 150 disposed on both sides thereof. The swing arm 154 and the two swing cams 150 are fixed to each other, and swing together about the cam shaft 120 as a unit.

  The swing arm 154 has a pair of support arms 155 disposed on both sides of the drive cam 122 and rotatably attached to the cam shaft 120, and is suspended from the cam shaft 120 by these support arms 155 (in FIG. 3). Only the back support arm 155 is shown). The swing arm 154 is curvedly extended from the support arm 155 toward the upstream side in the rotation direction of the cam shaft 120. A slide surface 156 is formed on the surface of the swing arm 154 that is curved toward the drive cam surface 124. The slide surface 156 is gently curved toward the drive cam 122 and is formed such that the distance from the cam basic circle (non-operation surface 124a) of the drive cam 122 increases toward the tip end. It should be noted that the distance from the cam basic circle of the drive cam 122 to the slide surface 156 is ensured to be equal to or greater than the cam height of the drive cam 122 even at the minimum portion.

  The swing cam 150 is provided with a swing cam surface 152 (152a, 152b) having the swing center, that is, the center of the cam shaft 120 as the center of the cam base circle. The swing cam surface 152 includes a non-working surface 152a and a working surface 152b having different profiles. 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 cam shaft 120. The working surface 152b is provided on the upstream side in the rotation direction of the cam shaft 120 with respect to the non-working surface 152a, and is connected to the non-working surface 152a so as to be smoothly continuous and directed toward the upstream side in the rotation direction of the cam shaft 120. Thus, the distance from the center of the cam shaft 120 (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 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 rocker arm 110 is arranged for each swing cam 150. The rocking cam surface 152 of the rocking cam 150 is in contact with the rocker roller 112 of the rocker arm 110. 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 biased by a valve spring (not shown) in a closing direction, that is, a direction in which the rocker arm 110 is pushed up. The rocker arm 110 is supported by the valve shaft 102 that receives the urging force of the valve spring, and the rocker roller 112 is pressed against the swing cam surface 152 by the hydraulic lash adjuster 106.

  The swing cam 150 is formed with a spring seat surface 148 for applying a lost motion spring (not shown). The spring seat surface 148 is provided on the downstream side in the rotation direction of the cam shaft 120 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 swing cam 150 is biased to rotate in a direction opposite to the rotation direction of the cam shaft 120 by a spring force acting on the spring seat surface 148 from the lost motion spring.

  The control shaft 132 is an axis parallel to the cam shaft 120 and is disposed with its relative position to the cam shaft 120 fixed. As shown in FIG. 1, the control shaft 132 is divided into a plurality of portions in the axial direction, and an eccentric shaft 166 is disposed between the divided control shaft 132 and the control shaft 132. Both ends of the eccentric shaft 166 are fixed to the control shaft 132 at positions eccentric from the center of the control shaft 132. Further, 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 link arm 164 is rotatably attached to the eccentric shaft 166. Two link arms 164 are provided at both ends of the eccentric shaft 166 in the axial direction, and the distal ends of the left and right link arms 164 are connected to each other by a connecting shaft 174. A first roller 170 is provided between the left and right link arms 164, and the first roller 170 is rotatably supported by the connecting shaft 174. Further, a second roller 172 having a smaller diameter than the first roller 170 is provided outside the left and right link arms 164, and each second roller 172 is rotatably supported by the connecting shaft 174. Both rollers 170, 172 are arranged so as to be sandwiched between the drive cam surface 124 and the slide surface 156, so that the first roller 170 is in contact with the drive cam surface 124 and each second roller 172 is in contact with the slide surface 156. Its axial position is adjusted. The first roller 170 has a larger diameter than the second roller 172, but a groove 158 is formed between the left and right slide surfaces 156, so that the first roller 170 enters the groove 158 so that the first roller 170 enters the groove 158. Contact between one roller 170 and the swing arm 154 is avoided.

[Operation of Variable Valve Operating Device of this Embodiment]
Next, the operation of the variable valve operating 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 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 is shown respectively.

  In the variable valve operating apparatus 100, the rotational motion of the drive cam 122 is first input to the first roller 170 that contacts the drive cam surface 124. The first roller 170 rotates around the eccentric shaft 166 together with the integrally provided second roller 172, and the movement is input to the slide surface 156 of the swing arm 154 that supports the second roller 172. Since the slide surface 156 is always pressed against the second roller 172 by the urging force of the lost motion spring (not shown), the swing cam arm 140 swings about the cam shaft 120 according to the rotation of the drive cam 122. To do.

  Specifically, when the camshaft 120 rotates from the state shown in FIG. 4A, as shown in FIG. 4B, the contact position P1 of the first roller 170 on the drive cam surface 124 (FIG. 4). 3) moves from the non-working surface 124a to the working surface 124b. The first roller 170 is relatively pushed down by the drive cam 122 and rotates around the eccentric shaft 166, and the slide surface 156 is pressed by the second roller 172 integrated with the first roller 170. The swing arm 154 that receives the pressing force from the second roller 172 on the slide surface 156 has a distance between the contact position P2 of the second roller 172 on the slide surface 156 (see FIG. 3) and the center of the cam shaft 120. Rotate in the direction of enlargement. In the present embodiment, the slide surface 156 is formed such that the distance from the cam base circle of the drive cam 122 increases toward the tip side (upstream side in the rotation direction of the cam shaft 120). The camshaft 120 rotates about the camshaft 120 in the rotation direction (clockwise direction in the figure). When the cam shaft 120 further rotates and the contact position P1 of the first roller 170 on the drive cam surface 124 passes the top of the working surface 124b, the swing arm 154 is now driven by the biasing force of the lost motion spring and the valve spring. Rotates around the cam shaft 120 in the direction opposite to the rotation direction of the cam shaft 120 (counterclockwise direction in the figure).

  As the swing arm 154 rotates about the cam shaft 120 in this way, the swing cam 150 integrated with the swing arm 154 also rotates about the cam shaft 120, and the rocker roller 112. The contact position P3 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. 4A, when the rocker roller 112 is in contact with the non-working surface 152a, the non-working surface 152a has a constant distance from the center of the camshaft 120. 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. 4B, 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 camshaft 120 and swings 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. At this time, the lift curve drawn by the valve 104 is as shown in FIG. The lift curve is determined by the cam profiles of the drive cam surface 122 and the swing cam surface 152 and the shape of the slide surface 156. As in the present embodiment, the slide surface 156 is formed in a shape curved toward the drive cam 122 so that the distance from the center of the cam shaft 120 gradually increases, so that a smooth lift curve as shown in FIG. 7 is obtained. Can be realized.

(2) Lift amount changing operation of variable valve apparatus Next, the lift amount changing operation of the variable valve apparatus 100 will be described with reference to FIGS. Here, FIG. 5 shows a state in which the variable valve apparatus 100 is operated so as to give a small lift to the valve 104. On the other hand, FIG. 4 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. 4 to the lift amount shown in FIG. 5, the control shaft 132 is rotationally driven in the state shown in FIG. 4A, and is eccentric to the position shown in FIG. The position of the shaft 166 is rotated. Since both rollers 170 and 172 are held at a fixed distance from the eccentric shaft 166 by the link arm 164, the rollers 170 and 172 rotate along the drive cam surface 124 with the rotation of the cam shaft 120 as the eccentric shaft 166 moves. Move upstream in the direction. The slide surface 156 that holds both the rollers 170 and 172 together with the drive cam surface 124 is formed so that the distance from the center of the cam shaft 120 increases toward the upstream side in the rotational direction of the cam shaft 120. Therefore, when the second roller 172 moves to the upstream side in the rotation direction of the cam shaft 120, the swing cam arm 140 receives a biasing force from the lost motion spring so that the slide surface 156 follows the second roller 172. The camshaft 120 tilts and rotates in the direction opposite to the rotation direction.

  The lift of the valve 104 is maximum when the contact position P1 of the first roller 170 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. 6 is a diagram showing the relationship between the position of the rocker roller 112 on the swing cam surface 152 and the valve lift. Since the swing angle width of the swing cam 150 that swings with the rotation of the drive cam 122 is constant, the final contact position P3f is on the swing cam surface 152 of the rocker roller 112 as shown in FIG. It is determined by the contact position P3i (hereinafter, initial contact position). When the swing cam arm 140 is tilted and rotated in the direction opposite to the rotation direction of the cam shaft 120 as described above, the initial contact position on the swing cam surface 152 of the rocker roller 112 as shown in FIG. P3i moves in a direction away from the action surface 152b. Thereby, the final contact position P3f moves to the non-operation surface 152a side.

  As shown in FIG. 6, the final contact position P3f moves toward the non-operation surface 152a, so that 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. Furthermore, when the first roller 170 moves upstream in the rotation direction of the cam shaft 120, the contact position P1 of the first roller 170 on the drive cam surface 124 when the cam shaft 120 is at the same rotation angle is It moves to the advance side of the drive cam 122. As a result, the swing timing of the swing cam 150 relative to the phase of the cam shaft 120 is advanced, and as a result, the valve timing (maximum lift timing) is advanced.

  FIG. 7 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. 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, the variable valve apparatus 100 according to the present embodiment changes the rotation angle of the control shaft 132 to change the rotation angle of the control shaft 132 on the drive cam surface 124 of the first roller 170 when the cam shaft 120 is at the same rotation angle. 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. In addition, since the swing cam arm 140 that transmits the rotational motion of the drive cam 122 to the valve 104 is supported by the cam shaft 120, variations in the inter-axis distance between the cam shaft 120 and the shaft of the swing cam arm 140 are caused. Thus, there is no deviation in the swing amount and swing timing of the swing cam 150. Therefore, according to the variable valve operating apparatus 100 of the present embodiment, the valve opening characteristics of the valve 104 can be variably controlled with high accuracy.

[Others]
The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, in the above-described embodiment, the present invention is applied to a rocker arm type valve gear, but it can also be applied to other types of valve gear 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 side view in the AA cross section of FIG. It is a side view in the BB cross section of FIG. 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

100 Variable valve gear 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 140 Oscillation cam arm 150 Oscillation cam 152 (152a, 152b) Oscillation Cam surface 154 Swing arm 156 Slide surface 158 Groove 164 Link arm 166 Eccentric shaft 170 First roller 172 Second roller P1 Contact position P2 of the first roller on the drive cam surface P2 Contact position of the second roller on the slide surface P3i Initial contact position on rocker cam surface of rocker roller P3f Final contact position on rocker cam surface of rocker roller

Claims (5)

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 swinging member rotatably attached to the camshaft and swinging about the camshaft;
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 is disposed between the drive cam and the swing member and contacts both the cam surface and the slide surface of the drive cam;
A control shaft provided in parallel with the cam shaft and capable of changing the rotation angle continuously or in multiple stages;
An interlocking mechanism that changes the position of the intermediate member on the drive cam at the same rotation angle of the camshaft in conjunction with the rotation of the control shaft;
A variable valve operating apparatus comprising:   The slide surface is curved so as to be curved toward the drive cam, and is formed so that a distance from the center of the cam shaft gradually increases from one end to the other end. Item 2. The variable valve operating device according to Item 1.   The interlock mechanism includes a control member that is fixed to the control shaft and has a fulcrum at a position eccentric from the center of the control shaft, and a connecting member that is swingably attached to the fulcrum and connects the intermediate member to the control member. The variable valve operating apparatus according to claim 1 or 2, characterized by comprising: 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,
2. The valve is lifted when the position of contact of the swing cam surface with the valve support member moves from the non-working surface to the working surface as the swinging member swings. 4. The variable valve operating device according to any one of items 1 to 3.   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 device according to any one of claims 1 to 4, further comprising a connecting shaft that connects the two shafts so as to be independently rotatable.

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