JP2009057868A - Variable valve gear and manufacturing method of rocking cam arm - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a variable valve gear capable of restraining a difference of an working angle and a lift amount between valves caused by the distortion of a control shaft without increasing a burden for manufacturing, and a manufacturing method of a rocking cam arm. <P>SOLUTION: The variable valve gear 100 is provided with a plurality of variable mechanisms 130 including the control shaft 132 rotated and driven by a motor 136, the rocking cam arm 150 which rocks in conjunction with the lift operation of the valve, and a link arm 164 for transmitting a pressing force of a driving cam 122 disposed at a cam shaft 120 to the rocking cam arm 150, and varying lift characteristics of the valve with respect to the rotation of the cam shaft 120 by the movement of the link arm 164 on a slide surface 156 formed at the rocking cam arm 150 according to a rotation angle of the control shaft 132. Slide surfaces 156 of the plurality of variable mechanisms 130 are formed of concentric circular arcs having different diameters depending on distances from the motor 136. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a variable valve operating apparatus, and more particularly to a variable valve operating apparatus capable of mechanically changing a valve opening characteristic of a valve and a method of manufacturing a swing cam arm used in the variable valve operating apparatus.

  Conventionally, for example, Japanese Patent Application Laid-Open No. 2005-226567 discloses a variable valve gear that can suppress a difference between valves in a working angle and a lift amount caused by twisting of a control shaft. According to this apparatus, a plurality of variable mechanisms that change the valve opening characteristics of the valve with respect to the rotation of the cam shaft in accordance with the rotational position of the control shaft are supported by the single control shaft that is rotationally driven by the actuator.

  In such a variable valve operating device, a reaction force of a spring such as a lost motion spring or a valve spring acts in the direction of closing the valve. The torsional moment associated with the reaction force is input to the control shaft through the variable mechanism, so that the control shaft is twisted. For this reason, the longer the distance from the actuator to the variable mechanism, the smaller the operating angle and the lift amount due to the twist of the control shaft. In the above-described conventional device, the initial values of the valve working angle and lift amount are set to different values for each variable mechanism in accordance with the distance from the actuator, so the working angle and lift amount associated with the twist of the control shaft. Can be offset by the magnitude of the initial value, and the difference between the operating angle and the lift amount between the valves is suppressed.

JP 2005-226567 A JP 2005-226666 A

  In the conventional variable valve system described above, as a device for setting the initial values of the valve working angle and lift amount to different values for each variable mechanism, the swing arm and cam shaft that swings in conjunction with the opening / closing operation of the valve are used. There has been proposed a variable valve apparatus that sets the positional relationship of a contact portion with a control arm that transmits input to a swing arm for each variable mechanism. Specifically, the operating angle and lift amount of the variable mechanism are increased by increasing the thickness of the contact portion of the swing arm of the variable mechanism whose operating angle and lift amount are reduced. The difference between the valve in the angle and the lift amount is suppressed.

  However, in the conventional variable valve apparatus described above, a different swing arm is required for each variable mechanism. For this reason, in the conventional variable valve operating apparatus that is not configured in consideration of the productivity of the plurality of swing arms, the manufacturing cost may increase.

  The present invention has been made to solve the above-described problems, and can suppress a difference between valves in a working angle and a lift amount caused by twisting of a control shaft without increasing a burden required for manufacturing. An object is to provide a variable valve operating apparatus.

  It is another object of the present invention to provide a method for efficiently manufacturing a plurality of types of swing cam arms used in a variable valve operating apparatus that can suppress a difference between valves in a working angle and a lift amount caused by twisting of a control shaft. To do.

In order to achieve the above object, a first invention is a variable valve gear,
A control shaft that is rotationally driven by an actuator, a swing cam arm that swings in conjunction with the lift operation of the valve, and an intermediate arm that transmits the pressing force of the drive cam provided on the cam shaft to the swing cam arm. A plurality of variable mechanisms that change the lift characteristics of the valve with respect to the rotation of the cam shaft by moving the intermediate arm on a slide surface provided on the swing cam arm according to the rotation angle of the control shaft. In the variable valve gear provided,
The slide surfaces of the plurality of variable mechanisms are formed of concentric arcs having different diameters according to the distance from the actuator.

The second invention is the first invention, wherein
The slide surface is formed by a concentric arc having a smaller diameter as the variable mechanism is farther from the actuator.

A third invention is a variable valve operating apparatus for achieving the above object,
A control shaft that is rotationally driven by an actuator, a swing cam arm that swings in conjunction with the lift operation of the valve, and an intermediate arm that transmits the pressing force of the drive cam provided on the cam shaft to the swing cam arm. A plurality of variable mechanisms that change the lift characteristics of the valve with respect to the rotation of the cam shaft by moving the intermediate arm on a slide surface provided on the swing cam arm according to the rotation angle of the control shaft. In the variable valve gear provided,
The slide surfaces of the plurality of variable mechanisms are formed by arcs having the same diameter and different central positions according to the distance from the actuator.

Moreover, 4th invention is set in 3rd invention,
The slide surface is formed of a circular arc having the same diameter in which the center position moves in a direction away from the slide surface as the variable mechanism is farther from the actuator.

A fifth invention is a method of manufacturing a swing cam arm in order to achieve the above object,
A control shaft that is rotationally driven by an actuator, a swing cam arm that swings in conjunction with the lift operation of the valve, and an intermediate arm that transmits the pressing force of the drive cam provided on the cam shaft to the swing cam arm. And the intermediate arm moves on a slide surface provided on the swing cam arm according to the rotation angle of the control shaft, thereby changing the lift characteristic of the valve with respect to the rotation of the cam shaft. A method of manufacturing a swing cam arm,
An arrangement step of arranging the swing cam arm at a predetermined position;
A polishing step of forming the slide surface by polishing the rocking cam arm by reciprocating a grindstone formed in a predetermined arc in the thickness direction of the rocking cam arm;
A classification step of classifying the rocking cam arm polished by the polishing step according to a wear state of the grindstone;
It is characterized by providing.

The sixth invention is the fifth invention, wherein
The arrangement step is characterized in that a plurality of the swing cam arms are uniformly stacked.

The seventh invention is a method of manufacturing a swing cam arm in order to achieve the above object,
A control shaft that is rotationally driven by an actuator, a swing cam arm that swings in conjunction with the lift operation of the valve, and an intermediate arm that transmits the pressing force of the drive cam provided on the cam shaft to the swing cam arm. And the intermediate arm moves on a slide surface provided on the swing cam arm according to the rotation angle of the control shaft, thereby changing the lift characteristic of the valve with respect to the rotation of the cam shaft. A method of manufacturing a swing cam arm,
An arrangement step of laminating a plurality of the swing cam arms at a predetermined position;
A polishing step of forming the slide surface by polishing the rocking cam arm by reciprocating a grindstone formed in a predetermined arc in the laminating direction of the rocking cam arm,
The arranging step is characterized in that at least one or more of the plurality of swing cam arms is disposed so as to protrude by a predetermined amount in the arc center direction of the slide surface.

The eighth invention is the seventh invention, wherein
The polishing step is characterized in that a rocking cam arm used in one variable valve operating apparatus including a plurality of the variable mechanisms is polished at a time.

  In each variable mechanism disposed on the control shaft, a reaction force of a spring such as a lost motion spring or a valve spring acts in a direction to close the valve. The torsional moment accompanying this reaction force is input to the control shaft through a variable mechanism. For this reason, the control shaft is twisted, and the valve operating angle and the lift amount are changed small. According to the first aspect, the slide surface of the swing cam arm of each variable mechanism is a concentric arc having different arc diameters according to the distance from the actuator. When the arc diameter of the slide surface is changed, the swing characteristic of the swing cam arm is changed. For this reason, according to this invention, the dispersion | variation in the working angle between each variable mechanism and a lift amount can be suppressed effectively.

  In addition, when manufacturing a rocking cam arm, if the grindstone that polishes the slide surface gradually wears and the arc diameter of the grind surface gradually decreases, the arc diameter of the slide surface can be reduced from one type of grindstone. A plurality of types of oscillating cam arms can be manufactured. For this reason, according to this invention, the dispersion | variation in the working angle between each variable mechanism and a lift amount can be suppressed effectively, without increasing the burden required for manufacture.

  According to the second invention, the swing cam arm having a smaller arc diameter of the slide surface is used as the twist of the control shaft is larger, that is, the variable mechanism is farther from the actuator. The smaller the arc diameter of the slide surface, the larger the operating angle is corrected. For this reason, according to this invention, the dispersion | variation in the working angle and lift amount by the twist of a control shaft can be suppressed effectively.

  In each variable mechanism disposed on the control shaft, a reaction force of a spring such as a lost motion spring or a valve spring acts in a direction to close the valve. The torsional moment accompanying this reaction force is input to the control shaft through a variable mechanism. For this reason, the control shaft is twisted, and the valve operating angle and the lift amount are changed small. According to the third aspect, the slide surface of the swing cam arm of each variable mechanism is an arc having the same diameter with different arc centers according to the distance from the actuator. When the arc center of the slide surface is changed, the swing characteristic of the swing cam arm is changed. For this reason, according to this invention, the dispersion | variation in the working angle between each variable mechanism and a lift amount can be suppressed effectively.

  Further, when manufacturing the swing cam arm, a plurality of types of swing cam arms with different arc centers of the slide surface from one type of grindstone are provided by making a difference in the positional relationship between the grindstone for polishing the slide surface and the swing cam arm. Can be manufactured. For this reason, according to this invention, the dispersion | variation in the working angle between each variable mechanism and a lift amount can be suppressed effectively, without increasing the burden required for manufacture.

  According to the fourth aspect of the present invention, the swing cam arm formed by shifting the center of the arc in the direction away from the slide surface is used as the torsion of the control shaft is larger, that is, the variable mechanism is farther from the actuator. The As the arc of the slide surface approaches the camshaft, the operating angle is corrected to be larger. For this reason, according to this invention, the dispersion | variation in the working angle and lift amount by the twist of a control shaft can be suppressed effectively.

  The slide surface of the swing cam arm is formed by polishing a swing cam arm disposed at a predetermined position with a grindstone processed into a predetermined arc. Here, the grindstone is worn by repeatedly executing the polishing process, and the arc diameter gradually decreases. According to the fifth aspect of the invention, the polished rocking cam arm is classified according to the wear state of the grindstone. For this reason, according to the present invention, it is possible to manufacture a plurality of types of swing cam arms having different arc diameters of the slide surface from one type of grindstone, and therefore it is possible to effectively improve the productivity of the swing cam arms. it can.

  According to the sixth aspect of the invention, the polishing process is performed by uniformly laminating the plurality of swing cam arms. For this reason, according to the present invention, it is possible to polish the slide surfaces of the plurality of swing cam arms in a single polishing step, and therefore it is possible to effectively improve the production efficiency of the swing cam arms.

  The slide surface of the swing cam arm is formed by polishing a plurality of stacked swing cam arms with a grindstone processed into a predetermined arc. According to the seventh invention, in the step of arranging the plurality of swing cam arms, at least one or more swing cam arms are disposed to project a predetermined amount in the arc center direction of the slide surface, that is, in the direction of the grinding surface of the grindstone. Is done. For this reason, according to the present invention, a plurality of types of slide surfaces having different arc centers can be polished in a single polishing step, so that the production efficiency of the swing cam arm can be improved.

  According to the eighth aspect, since the swing cam arm used in one variable valve operating apparatus having a plurality of the variable mechanisms can be polished at a time, the relative processing error between the swing cam arms is minimized. To the limit. For this reason, according to this invention, the shift | offset | difference of the working angle and lift amount in each variable mechanism in a variable valve apparatus can be suppressed effectively.

  Several embodiments of the present invention will be described below with reference to the drawings. In addition, the same code | symbol is attached | subjected to the element which is common in each figure, and the overlapping description is abbreviate | omitted. The present invention is not limited to the following embodiments.

Embodiment 1 FIG.
[Configuration of Embodiment 1]
FIG. 1 is a side view showing the configuration of the variable valve apparatus 100 according to the present embodiment. The variable valve operating apparatus 100 has a rocker arm type mechanical valve operating mechanism, and the rotational motion of the cam shaft 120 is converted into the swing motion of the rocker arm 110 by a drive cam 122 provided on the cam shaft 120. This is converted into a lift movement in the vertical direction 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-operating surface 124a, which is one cam surface, is a circumferential surface of the cam base circle, and is formed such that the distance from the center of the cam shaft 120 gradually increases and gradually decreases after exceeding the top. In this 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 apparatus 100 variably controls the variable mechanism 130 to change the rocking amount and the rocking timing of the rocker arm 110 to continuously adjust the valve opening characteristics of the valve 104 such as the lift amount, the working angle, and the valve timing. Can be changed automatically. Hereinafter, the variable mechanism 130 will be described in more detail.

  The variable mechanism 130 includes a control shaft 132 parallel to the cam shaft 120. The rotation angle of the control shaft 132 can be controlled to an arbitrary angle by a motor 136 described later. A control arm 162 is fixed to the control shaft 132. The control arm 162 protrudes in the radial direction of the control shaft 132, and an arcuate link arm 164 is attached to the protruding portion. The rear end of the link arm 164 is rotatably connected to the control arm 162 by a pin 166. The position of the pin 166 is eccentric from the center of the control shaft 132, and this pin 166 becomes a swing fulcrum of the link arm 164.

  A swing cam arm 150 is swingably supported on the control shaft 132. The swing cam arm 150 is disposed with its tip directed upstream in the rotational direction of the drive cam 122. A slide surface 156 that contacts a second roller 174 described later is formed on the side of the swing cam arm 150 facing the drive cam 122. The slide surface 156 is gently curved toward the drive cam 122 side, and the distance from the cam base surface (non-operation surface 124a) of the drive cam 122 increases as the distance from the center of the control shaft 132 that is the center of oscillation increases. Is formed.

  On the side of the swing cam arm 150 opposite to the slide surface 156, swing cam surfaces 152 (152a, 152b) are formed. The swing cam surface 152 includes a non-operation surface 152a and an operation 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 control shaft 132. On the other hand, the action surface 152b is provided on the distal end side of the swing cam arm 150, is connected to the non-action surface 152a so as to be smoothly continuous, and extends from the center of the control shaft 132 toward the tip of the swing cam arm 150. The distance (that is, the cam height) is formed so as to increase gradually. 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.

  A first roller 172 and a second roller 174 are arranged between the slide surface 156 of the swing cam arm 150 and the drive cam surface 124 of the drive cam. Both the first roller 172 and the second roller 174 are rotatably supported by a connecting shaft 176 fixed to the tip of the link arm 164 described above. Since the link arm 164 can swing around the pin 166 as a fulcrum, the rollers 172 and 174 can also swing along the slide surface 156 and the drive cam surface 124 while maintaining a certain distance from the pin 166. The drive cam 122 and the swing cam arm 150 are displaced in the axial direction of the cam shaft 120, the first roller 172 is in contact with the drive cam surface 124, and the second roller 174 is in contact with the slide surface 156.

  The swing cam arm 150 is provided with a lost motion spring (not shown). The lost motion spring is a compression spring, and the urging force from the lost motion spring acts as an urging force that presses the slide surface 156 against the second roller 174, and further, the first roller 172 coaxially integrated with the second roller 174 It acts as an urging force that presses against the drive cam surface 124. Accordingly, the first roller 172 and the second roller 174 are positioned by being sandwiched between the slide surface 156 and the drive cam surface 124 from both sides.

  A rocker arm 110 is disposed below the 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 lasher adjuster 106. The valve shaft 102 is biased by a valve spring (not shown), that is, in a direction to push up the rocker arm. The rocker roller 112 is pressed against the swing cam surface 152 of the swing cam arm 150 by this biasing force and the hydraulic lash adjuster 106. It has been.

[Operation in Embodiment 1]
Next, the operation of the variable valve operating apparatus 100 will be described with reference to FIGS.

(Lift operation of variable valve gear)
First, the lift operation of the variable valve operating apparatus according to the present embodiment will be described with reference to FIG. In the figure, (A) shows the state of the variable valve system when the valve 104 is closed during the lift operation, and (B) shows that the valve 104 is fully opened during the lift operation. The state of the variable valve operating apparatus when the vehicle is in operation is shown.

  In the variable valve operating apparatus 100, the rotational motion of the drive cam 122 is first input to the first roller 172 that contacts the drive cam surface 124. The first roller 172 swings around the pin 166 together with the second roller 174 provided coaxially, and the movement is input to the slide surface 156 of the swing cam arm 150 supporting the second roller 174. . Since the slide surface 156 is always pressed against the second roller 174 by the biasing force of the lost motion spring, the swing cam arm 150 is controlled by the control shaft according to the rotation of the drive cam 122 transmitted through the second roller 174. It swings around 132.

  Specifically, when the camshaft 120 rotates from the state shown in FIG. 2A, the contact position of the first roller 172 on the drive cam surface 124 is driven as shown in FIG. The top of the cam 122 is approached. The first roller 172 is relatively pushed down by the drive cam 122, and the swing cam arm 150 is pushed down the slide surface 156 by the second roller 174 integrated with the first roller 172. As a result, the swing cam arm 150 rotates about the control shaft 132 in the clockwise direction in the figure.

  When the contact position of the rocker roller 112 on the rocking cam surface 152 is switched from the non-working surface 152a to the working surface 152b by the rotation of the rocking cam arm 150, the rocker arm 110 is moved from the center of the control shaft 132 of the working surface 152b. And is swung clockwise around the support point by the hydraulic lash adjuster 106. As a result, the valve 104 is pushed down by the rocker arm 110 to open. As shown in FIG. 2B, when the contact position of the first roller 172 on the drive cam surface 124 reaches the top of the drive cam 122, the rotation amount of the swing cam arm 150 is maximized, The lift amount of the valve 104 is also maximized.

  When the camshaft 120 further rotates and the contact position of the first roller 172 on the drive cam surface 124 passes the top of the drive cam 122, the swing cam arm 150 is now moved by the urging force of the lost motion spring and the valve spring. It rotates counterclockwise in the figure around the control shaft 132. As the swing cam arm 150 rotates counterclockwise, the contact position of the rocker roller 112 on the swing cam surface 152 moves to the non-operation surface 152a side. As a result, the lift amount of the valve 104 decreases, and as shown in FIG. 2A, the contact position of the rocker roller 112 on the rocking cam surface 152 is changed from the working surface 152b to the non-working surface 152a. When the switch is made, the lift amount of the valve 104 becomes zero. That is, the valve 104 is closed.

(Lift amount change operation of variable valve system)
Next, the lift amount changing operation of the variable valve operating apparatus according to the present embodiment will be described with reference to FIGS. 3 and 4. 3A shows a state of the variable valve operating apparatus 100 at the maximum lift when the variable valve operating apparatus 100 operates so as to give a large lift to the valve 104 (see FIG. 1, omitted in the figure). (B) shows the state of the variable valve apparatus 100 at the maximum lift when the variable valve apparatus 100 operates to give a small lift to the valve 104, respectively.

  When the lift amount is changed from the lift amount shown in FIG. 3A to the lift amount shown in FIG. 3B, the control shaft 132 is reverse to the rotation direction of the cam shaft 120 in the state shown in FIG. The control arm 162 is rotated in the direction (counterclockwise direction in the drawing) to rotate the control arm 162 to the rotation angle shown in FIG. As the control arm 162 rotates, the second roller 174 moves along the slide surface 156 in a direction away from the control shaft 132. At the same time, the first roller 172 moves along the drive cam surface 124 upstream in the rotation direction. Moving.

  When the second roller 174 moves away from the control shaft 132, the distance from the swing center of the swing cam arm 150 to the contact position P2 on the slide surface 156 of the second roller 174 becomes longer, and the swing cam arm The swing angle width of 150 decreases. This is because the swing angle width of the swing cam arm 150 is inversely proportional to the distance from the swing center to the contact position P2, which is the vibration input point. As a result of the decrease in the swing angle width of the swing cam arm 150, the final contact position P3 that can be reached by the rocker roller 112 moves on the working surface 152b toward the non-working surface 152a, and the lift amount of the valve 104 decreases.

  The period during which the rocker roller 112 is positioned on the working surface 152b (crank angle) is the working angle of the valve 104, but the final contact position P3 moves to the non-working surface 152a side. The working angle is also reduced. Furthermore, when the first roller 172 moves upstream in the rotation direction of the cam shaft 120, the contact position P1 of the first roller 172 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 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. 4 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 of the present embodiment. As shown in this figure, according to the variable valve apparatus 100 of the present embodiment, 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, conversely. The operating angle can be decreased and the valve timing can be advanced in conjunction with a decrease in the lift amount of the valve 104.

[Features of this embodiment]
Next, the characteristic configuration and operation of the present embodiment will be described with reference to FIGS. A plurality of variable valve gears 100 are mounted on the engine according to the number of cylinders. FIG. 5 is a diagram showing an arrangement when the variable valve apparatus 100 of the present embodiment is applied to an in-line four-cylinder engine. In the figure, (A) is a view seen from a direction perpendicular to the axial direction of the control shaft 132, and (B) is a view seen from the direction B in (A). As shown in this figure, a worm wheel 134 is fixed to one end of the control shaft 132. On the control shaft 132, variable valve gears 100a, 100b, 100c, and 100d are arranged in order from the side on which the worm wheel 134 is fixed. Referred to as the valve device 100). A worm gear 138 fixed to the output shaft of the motor 136 is engaged with the worm wheel 134.

  According to such a configuration, by controlling the rotation angle of one control shaft 132, the variable valve systems 100 of all the four cylinders are simultaneously controlled, and the operating angles and lift amounts of all the valves 104 are simultaneously changed. be able to. Specifically, the rotation of the motor 136 is input to the worm wheel 134 via the worm gear 138, whereby the rotation angle of the control shaft 132 is changed, and the operating angle and the lift amount of all the valves 104 are simultaneously changed. The

  Here, as described above, the urging force of the lost motion spring and the valve spring always acts on the swing cam arm 150 in each variable valve operating apparatus 100. These urging forces act as forces that cause the control shaft 132 to rotate counterclockwise in FIG. 1 via the second roller 174, the link arm 164, and the control arm 162. Since one end of the control shaft 132 is restrained by the worm wheel 134 and the worm gear 138, a torsional moment acts on the control shaft 132. Thereby, the control shaft 132 is twisted in the counterclockwise direction in FIG.

  As the control shaft 132 is twisted counterclockwise, the second roller 174 moves along the slide surface 156 away from the control shaft 132, and at the same time, the first roller 172 moves along the drive cam surface 124. Move upstream in the direction of rotation. As a result, the second roller 174 moves away from the control shaft 132, and the swing angle width of the swing cam arm 150 decreases. For this reason, the operating angle and the lift amount of the valve 104 are reduced. The amount of decrease in the operating angle and the lift amount increases as the twist amount of the control shaft 132 increases. Here, the amount of twist of the control shaft 132 increases as the distance from the fixed end (one end on the worm wheel 134 side) of the control shaft 132 increases. In other words, the variable valve operating apparatus 100 of the cylinder farther from the worm wheel 134 side in the control shaft 132 decreases the operating angle and the lift amount due to the twist of the control shaft 132.

  Therefore, in this embodiment, a plurality of types of swing cam arms 150 with different curvatures of the slide surface 156 are prepared, and the swing cam arm 150 to be used is selected according to the distance from the fixed end of the control shaft 132. . FIG. 6 is a view for explaining the shape of the slide surface 156 of the swing cam arm 150. As shown in this figure, the slide surface 156 is formed by an arc from a certain center. Therefore, first, a plurality of types of swing cam arms 150 which are concentric arcs of the slide surface 156 and whose arc radius is changed are manufactured by a manufacturing method described later. For example, four types of swing cam arms 150 having a circular arc radius smaller by 20 μm than the reference circular arc are manufactured.

  FIG. 7 is a diagram showing the relationship between the arc radius of the slide surface 156 and the operating angle in the swing cam arm 150. In the figure, (A) shows the operation in the swing cam arm 150 having the reference arc slide surface 156, and (B) in the swing cam arm 150 having the concentric arc slide surface 156 smaller than the reference arc. The operation is shown. As shown in this figure, when the arc of the slide surface 156 is changed to a smaller concentric arc, the slide surface 156 of the swing cam arm 150 is displaced downward by the decrease of the arc radius, and the swing cam arm 150 causes the control shaft 132 to move. Rotate clockwise around the center. By the rotation of the rocking cam arm 150, the initial contact position P4 of the rocker roller 112 on the rocking cam surface 152 relatively moves on the non-working surface 152a toward the working surface 152b. As a result, the distance between the initial contact position P4 and the action surface 152b is reduced, and as a result, the action angle and the lift amount of the valve 104 are increased.

  The relationship between the arc radius of the slide surface 156 and the amount of increase in the operating angle of the valve 104 can be calculated based on the design value and the actual measurement value (for example, when the arc radius of the slide surface 156 is reduced by 10 μm, the operating angle is 0.5-1.0 ° CA increase). On the other hand, the torsion amount of the control shaft 132 can be calculated based on design values or measured values such as the magnitude of the urging force of the lost motion spring and the valve spring, the shaft shape, etc. (for example, the control shaft 132 is 0.5 deg. When twisted, the working angle decreases by 1-2 ° CA). Therefore, if the arc diameter of the slide surface 156 of the swing cam arm 150 is determined so as to cancel out the decrease in the operating angle due to the twist, variations in the operating angle and the lift amount among the cylinders can be suppressed. . More specifically, the swinging cam arm 150 having the smaller concentric arc slide surface 156 is used as the decrease in the operating angle due to torsion, that is, the variable valve operating device 100 of the cylinder farther from the fixed end of the control shaft 132 is used. Is done. Thereby, the variation of the working angle between the cylinders due to the twist of the control shaft 132 can be effectively suppressed.

[Manufacturing method of swing cam arm]
Next, a manufacturing method of the swing cam arm 150 will be described with reference to FIG. FIG. 8 is a view for explaining a method of processing the slide surface 156 of the swing cam arm 150. In the figure, (B) shows a view from the direction B in (A). As shown in this figure, the slide surface 156 of the swing cam arm 150 is processed simultaneously by stacking a plurality of swing cam arms 150 in a row. Specifically, the polishing surface of the grindstone 10 is processed into a reference arc of the slide surface 156. For this reason, when the grindstone 10 reciprocates in the stacking direction of the swing cam arms 150 and polishes the swing cam arms 150 with the polishing surface, the slide surface 156 is processed into a reference arc.

  When the above operation is repeated, the polishing surface of the grindstone 10 is gradually worn down. For this reason, the arc of the polishing surface gradually becomes a concentric arc having a small diameter. Therefore, in the present embodiment, the slide surfaces 156 of various ranks are processed using the change in the arc shape of the grindstone 10. Specifically, the wear amount of the polished surface of the grindstone 10 can be estimated in relation to the number of operations. Accordingly, when the above-described processing method is executed a plurality of times and it is estimated that the grindstone 10 has been worn down by a predetermined amount (for example, 20 μm), the processing is executed a plurality of times with the arc diameter being reduced by one step. Next, when it is estimated that the grindstone 10 has been further worn down by a predetermined amount (for example, 20 μm), the machining is performed a plurality of times with the arc diameter being two ranks smaller. Thus, by dividing the swing cam arm 150 processed in relation to the number of operations, the rank of the arc diameter of the slide surface 156 can be efficiently classified.

  Further, when only one type of tolerance range slide surface 156 is processed with one grindstone, it is necessary to replace it with a new grindstone when it falls outside the tolerance range due to wear of the grindstone. In addition, if a plurality of types of slide surfaces 156 are processed according to wear, one grindstone can be used continuously, and the frequency of exchanging the grindstone can be efficiently reduced. Further, according to the manufacturing method of the present embodiment, it is possible to process the swing cam arms 150 of various ranks using a single grindstone, so there is no need to prepare grindstones of various arc diameters. For this reason, the cost concerning manufacture can be suppressed efficiently and productivity can be improved.

  By the way, in Embodiment 1 mentioned above, when processing the slide surface 156 of the rocking cam arm 150, the wear amount of the grindstone is estimated based on the number of operations of the grindstone 10, but the grindstone wear state This determination method is not limited to this, and the wear amount may be determined by directly measuring a grindstone, or the measured slide surface 156 of the swing cam arm 150 may be directly measured and determined.

  In the first embodiment described above, the worm wheel 134 is disposed at the end of the control shaft 132, and the motor 136 as an actuator is connected via the worm gear 138. The position is not limited to the end of the control shaft 132. That is, for example, when the control shaft is long, such as in the case of in-line 6 cylinders, an actuator may be connected near the center of the control shaft 132. Even in such a case, the shape of the slide surface 156 may be set according to the distance from the actuator.

  In the first embodiment, the link arm 164 corresponds to the “intermediate arm” in the first invention, and the motor 136 corresponds to the “actuator” in the first invention.

  In the first embodiment described above, the link arm 164 corresponds to the “intermediate arm” in the fifth aspect of the invention, and the motor 136 corresponds to the “actuator” in the fifth aspect of the invention.

Embodiment 2. FIG.
[Features of Embodiment 2]
Next, the characteristic configuration and operation of the present embodiment will be described with reference to FIG. 9 or FIG. In the first embodiment described above, a plurality of types of swing cam arms 150 with different arc diameters of the slide surface 156 are manufactured. In an engine in which a plurality of variable valve devices 100 are fixed to the control shaft 132, the swinging cam arm 150 having a smaller arc diameter of the slide surface 156 is smaller as the variable valve device is farther from the fixed end of the control shaft 132. Is used. Thereby, the variation of the working angle due to the twist of the control shaft 132 is effectively suppressed.

  Here, even if the shape of the slide surface 156 is not the above-mentioned concentric arc, if the height of the slide surface 156 can be changed, it is possible to correct the operating angle reduced due to the influence of the twist of the control shaft 132. Become. Thus, in the second embodiment, the arc diameter of the slide surface 156 is not changed, and a plurality of types of swing cam arms 150 in which the arc center of the slide surface is changed are used properly according to the distance from the fixed end of the control shaft 132. I will do it.

  FIG. 9 is a view for explaining the shape of the slide surface 156 of the swing cam arm 150. As shown in this figure, the slide surface 156 is formed in a predetermined arc. More specifically, the slide surface 156 is formed as an arc centered at a position at a predetermined height from the reference surface with the swing cam surface 152 at the tip of the swing cam arm 150 as a reference surface.

  Therefore, in the present embodiment, first, a plurality of types of swing cam arms 150 that are arcs having the same diameter as the slide surface 156 and whose arc center positions are changed are manufactured by a manufacturing method described later. For example, four types of oscillating cam arms 150 in which the arc center is 20 μm higher than the reference arc are produced.

  When the center height of the slide surface 156 is changed to an arc higher than the center height of the reference arc, the slide surface 156 of the rocking cam arm 150 is displaced downward by the height increase of the center of the arc as in FIG. 7B. The swing cam arm 150 rotates clockwise about the control shaft 132. By the rotation of the swing cam arm 150, the initial contact position of the rocker roller 112 on the swing cam surface 152 relatively moves on the non-working surface 152a toward the working surface 152b. Thereby, the distance between the initial contact position and the action surface 152b is reduced, and as a result, the action angle and the lift amount of the valve 104 are increased.

  The relationship between the arc center height of the slide surface 156 and the amount of increase in the operating angle of the valve 104 can be calculated based on the design value and the actual measurement value (for example, if the arc center height of the slide surface 156 is increased by 10 μm, The working angle is increased by 0.5 to 1.0 ° CA). On the other hand, the torsion amount of the control shaft 132 can be calculated based on design values or measured values such as the magnitude of the urging force of the lost motion spring and the valve spring, the shaft shape, etc. (for example, the control shaft 132 is 0.5 deg. When twisted, the working angle decreases by 1-2 ° CA). Therefore, if the arc height of the slide surface 156 of the swing cam arm 150 is determined so as to offset the decrease in the operating angle due to the twist, the variation in the operating angle and the lift amount between the cylinders can be suppressed. it can. Specifically, the greater the decrease in the operating angle due to torsion, that is, the more the variable valve gear 100 of the cylinder farther from the fixed end of the control shaft 132, the higher the swing cam arm 150 with the arc center height of the slide surface 156 becomes higher. used. Thereby, the variation of the working angle between the cylinders due to the twist of the control shaft 132 can be effectively suppressed.

[Manufacturing method of swing cam arm]
Next, a method for manufacturing the swing cam arm 150 will be described with reference to FIG. FIG. 10 is a view for explaining a method of processing the slide surface 156 of the swing cam arm 150. In the figure, (B) shows a view from the direction B in (A). As shown in this figure, in the processing method of the slide surface 156 in the present embodiment, a plurality of swing cam arms 150 for one engine (for example, when two cylinders are used for each cylinder in a four-cylinder engine) 8) are processed at the same time. More specifically, as shown in FIG. 10A, the swing cam arm 150 used for each cylinder is arranged by being shifted by a predetermined amount (for example, by 20 μm) in the height direction from the reference plane. . The polishing surface of the grindstone 10 is processed into a reference arc of the slide surface 156. For this reason, when the grindstone 10 reciprocates in the row direction of the swing cam arms 150 and is polished by the polishing surface, the slide surface 156 is processed into a reference arc. Thereby, a plurality of types of swing cam arms 150 having different arc centers of the slide surface 156 can be produced.

  As described above, if the slide surface 156 of the swing cam arm 150 for one engine is processed simultaneously, the variation in the dimensional difference of the swing cam arm 150 between the cylinders, that is, the height of the center of the arc of the slide surface 156 is reduced. Variation in the difference can be minimized. Thereby, the dispersion | variation in the working angle which generate | occur | produces between each cylinder can be suppressed effectively.

  In the second embodiment described above, the worm wheel 134 is disposed at the end of the control shaft 132, and the motor 136 as an actuator is connected via the worm gear 138. The position is not limited to the end of the control shaft 132. That is, for example, when the control shaft is long, such as in the case of in-line 6 cylinders, an actuator may be connected near the center of the control shaft 132. Even in such a case, the shape of the slide surface 156 may be set according to the distance from the actuator.

  In the second embodiment described above, the link arm 164 corresponds to the “intermediate arm” in the third invention, and the motor 136 corresponds to the “actuator” in the third invention.

  In the second embodiment, the link arm 164 corresponds to the “intermediate arm” in the seventh invention, and the motor 136 corresponds to the “actuator” in the seventh invention.

It is a side view which shows the structure of the variable valve apparatus concerning Embodiment 1 of this invention. It is a figure which shows the lift operation of the variable valve apparatus shown in FIG. 1, (A) has shown the valve closing time, (B) has shown the valve opening time. It is a figure which shows the change operation | movement of the lift amount of the variable valve apparatus shown in FIG. 1, (A) is at the time of a big lift, (B) has shown at the time of a small lift. It is a figure which shows the relationship between valve timing and lift amount. It is a figure which shows arrangement | positioning at the time of applying the variable valve apparatus concerning Embodiment 1 of this invention to an in-line 4 cylinder engine. It is a figure for demonstrating the shape of the slide surface of the rocking cam arm concerning Embodiment 1 of this invention. It is a figure which shows the relationship between the shape of a slide surface of the rocking cam arm concerning Embodiment 1 of this invention, and an operating angle. It is a figure for demonstrating the method to process the slide surface of the rocking cam arm concerning Embodiment 1 of this invention. It is a figure for demonstrating the shape of the slide surface of the rocking cam arm concerning Embodiment 2 of this invention. It is a figure for demonstrating the method to process the slide surface of the rocking cam arm concerning Embodiment 2 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Variable valve apparatus 102 Valve shaft 104 Valve 106 Hydraulic lash adjuster 110 Rocker arm 112 Rocker roller 120 Cam shaft 122 Driving cam 124 Driving cam surface 124a Non-operation surface 124b Operation surface 130 Variable mechanism 132 Control shaft 134 Worm wheel 136 Motor 138 Worm gear 150 Swing cam arm 152 Swing cam surface 152a Non-working surface 152b Working surface 156 Slide surface 162 Control arm 164 Link arm 166 Pin 172 First roller 174 Second roller 176 Connecting shaft

Claims (8)

A control shaft that is rotationally driven by an actuator, a swing cam arm that swings in conjunction with the lift operation of the valve, and an intermediate arm that transmits the pressing force of the drive cam provided on the cam shaft to the swing cam arm. A plurality of variable mechanisms that change the lift characteristics of the valve with respect to the rotation of the cam shaft by moving the intermediate arm on a slide surface provided on the swing cam arm according to the rotation angle of the control shaft. In the variable valve gear provided,
The variable valve operating device, wherein the slide surfaces of the plurality of variable mechanisms are formed by concentric arcs having different diameters according to the distance from the actuator.   The variable valve operating apparatus according to claim 1, wherein the slide surface is formed by a concentric arc having a smaller diameter as the variable mechanism is farther from the actuator. A control shaft that is rotationally driven by an actuator, a swing cam arm that swings in conjunction with the lift operation of the valve, and an intermediate arm that transmits the pressing force of the drive cam provided on the cam shaft to the swing cam arm. A plurality of variable mechanisms that change the lift characteristics of the valve with respect to the rotation of the cam shaft by moving the intermediate arm on a slide surface provided on the swing cam arm according to the rotation angle of the control shaft. In the variable valve gear provided,
The variable valve operating device according to claim 1, wherein the slide surfaces of the plurality of variable mechanisms are formed by arcs having the same diameter and different central positions according to the distance from the actuator.   The variable movement according to claim 3, wherein the slide surface is formed by an arc having the same diameter in which the center position moves in a direction away from the slide surface as the variable mechanism is further away from the actuator. Valve device. A control shaft that is rotationally driven by an actuator, a swing cam arm that swings in conjunction with the lift operation of the valve, and an intermediate arm that transmits the pressing force of the drive cam provided on the cam shaft to the swing cam arm. And the intermediate arm moves on a slide surface provided on the swing cam arm according to the rotation angle of the control shaft, thereby changing the lift characteristic of the valve with respect to the rotation of the cam shaft. A method of manufacturing a swing cam arm,
An arrangement step of arranging the swing cam arm at a predetermined position;
A polishing step of forming the slide surface by polishing the rocking cam arm by reciprocating a grindstone formed in a predetermined arc in the thickness direction of the rocking cam arm;
A classification step of classifying the rocking cam arm polished by the polishing step according to a wear state of the grindstone;
A method for manufacturing a rocking cam arm comprising:   6. The method of manufacturing a rocking cam arm according to claim 5, wherein in the arranging step, a plurality of the rocking cam arms are uniformly stacked. A control shaft that is rotationally driven by an actuator, a swing cam arm that swings in conjunction with the lift operation of the valve, and an intermediate arm that transmits the pressing force of the drive cam provided on the cam shaft to the swing cam arm. And the intermediate arm moves on a slide surface provided on the swing cam arm according to the rotation angle of the control shaft, thereby changing the lift characteristic of the valve with respect to the rotation of the cam shaft. A method of manufacturing a swing cam arm,
An arrangement step of laminating a plurality of the swing cam arms at a predetermined position;
A polishing step of forming the slide surface by polishing the rocking cam arm by reciprocating a grindstone formed in a predetermined arc in the laminating direction of the rocking cam arm,
In the arranging step, at least one or more of the plurality of rocking cam arms is disposed so as to protrude by a predetermined amount in the arc center direction of the slide surface. .   8. The method of manufacturing a rocking cam arm according to claim 7, wherein the polishing step comprises polishing a rocking cam arm used in one variable valve operating apparatus having a plurality of the variable mechanisms at a time.

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