JP4106556B2 - Valve operating device for internal combustion engine - Google Patents

Description

  The present invention relates to a valve gear for an internal combustion engine (hereinafter referred to as an engine).

In order to realize an optimum engine output characteristic corresponding to the operating region, various engines have been proposed in which the intake / exhaust valve opening period, the lift amount, and the like are switched (for example, see Patent Document 1). .
In the engine described in Patent Document 1, the driven rocker arm supported on the rocker shaft is swung by the first low-speed cam to open and close the intake valve, and is supported on the rocker shaft adjacent to the driven rocker arm. The drive rocker arm is swung by the second cam for high speed. In the cylinder formed on the driven rocker arm, a piston is slidably disposed by hydraulic pressure, and on the driving rocker arm, an engaging protrusion that can be engaged with the piston is formed along with the swing.

For example, in the low engine speed range, the piston of the driven rocker arm is switched to the lower position and the engagement protrusion of the drive rocker arm is swung to drive the intake valve to open and close following the shape of the first cam by the driven rocker arm. In the high rotation range of the engine, the piston of the driven rocker arm is switched to the upper position and pressed by the engagement protrusion of the drive rocker arm, so that the driven rocker arm is swung together with the drive rocker arm to follow the shape of the second cam. Open and close the intake valve.
JP 2001-41017 A

  By the way, the upper part of the piston is pressed by the engagement protrusion of the drive rocker arm, and the entire driven rocker arm is swung against the inertial mass, so that it is higher than the lower part of the piston that mainly receives hydraulic pressure. Rigidity is required. Since the damage of the piston is directly connected to the inability to switch the valve operating device, the engine of Patent Document 1 described above manufactures the entire piston with a material that can satisfy the characteristics required for the upper part of the piston. The manufacturing cost of the piston alone inevitably increased, and since the piston is required for each driven rocker arm of each cylinder, the influence on the manufacturing cost of the entire valve operating device could not be ignored.

  The purpose of the present invention is to improve the reliability by preventing troubles such as damage to the piston that switches the operating state, and to reduce the manufacturing cost of the piston, and hence the manufacturing cost of the entire valve operating device. An object of the present invention is to provide a valve operating device for an internal combustion engine.

  In order to achieve the above object, the invention according to claim 1 is directed to a first rocker arm whose tip is linked to one of an intake valve and an exhaust valve, and is swingably supported on the first rocker shaft, and the first rocker arm. Adjacently swingably supported by the first rocker shaft, the second rocker arm driven by the first cam, the tip is linked to the other of the intake valve or the exhaust valve, and arranged in parallel with the first rocker shaft A fourth rocker arm swingably supported by the second rocker shaft, and a fifth rocker pivotally supported by the second rocker shaft adjacent to the fourth rocker arm and driven by the third cam. A rocker arm, a first piston slidably mounted on a first cylinder formed on the first rocker arm, and a third piston slidably mounted on a third cylinder formed on the fourth rocker arm. A first engagement protrusion extending from the second rocker arm and engagable with the first piston, and extending from the fifth rocker arm and engagable with the third piston. First and third switching mechanisms for switching the positions of the third engagement protrusions, the first and third pistons between the engagement positions and the non-engagement positions with respect to the first and third engagement protrusions, respectively; And a control means for controlling switching of the third switching mechanism, wherein the first and third pistons are engaged with the first portion engaged with the first and third engaging protrusions, and the first and third engaging protrusions. The second part that is not engaged is divided into two parts in the vertical direction.

  Therefore, the first and third switching mechanisms switch the first and third pistons between the engaged position and the non-engaged position. When the first and third pistons are in the engaged position, the first piston is moved to the first piston. The first engagement protrusions of the two rocker arms are engaged to drive the first rocker arm to open or close one of the intake valve or the exhaust valve in accordance with the shape of the first cam, and the fifth piston to the third piston. The third engagement protrusion engages, and the fourth rocker arm follows the shape of the third cam to open and close the other of the intake valve and the exhaust valve. When the first and third pistons are in the non-engagement positions, the engagement protrusions are not engaged with the pistons, and the first and fourth rocker arms hold the corresponding intake or exhaust valves closed. Therefore, the operating state of the internal combustion engine is switched according to the above switching.

  The first portion of the first piston engages with the first engagement protrusion every time the second rocker arm swings, and the entire first rocker arm is moved to inertial mass with the engagement of the first engagement protrusion. The first portion of the third piston engages with the third engagement protrusion every time the fifth rocker arm swings, and the fourth portion is engaged with the engagement of the third engagement protrusion. Since the entire rocker arm is rocked against the inertial mass, mechanical properties different from those of the second portion not engaged with the first engagement protrusion or the third engagement protrusion are required. By dividing the first and third pistons into two parts, a first part and a second part, it is possible to apply a material according to each request to each part. For example, the first and third pistons are engaged with the first and third engaging protrusions. It is possible to manufacture the first portion with a material that does not break even if they are combined, and to manufacture the second portion with a less expensive material.

  The invention according to claim 2 is a first rocker arm whose tip is linked to one of an intake valve or an exhaust valve, and is swingably supported by the rocker shaft, and a rocker shaft adjacent to one side of the first rocker arm. A second rocker arm that is swingably supported and driven by a first cam for low speed, and a rocker shaft that is swingably supported adjacent to the other side of the first rocker arm and that is A third rocker arm driven by two cams, a first piston slidably mounted on a first cylinder formed on the first rocker arm, and a first rocker arm formed adjacent to the first cylinder. A second piston slidably mounted on the second cylinder, a first engagement protrusion extending from the second rocker arm and engagable with the first piston, and a third rocker arm Extended The position of the second engagement protrusion provided so as to be engageable with the second piston and the first and second pistons is switched between the engagement position and the non-engagement position with respect to the first and second engagement protrusions, respectively. The first piston includes a first and second switching mechanism, and a control means for controlling switching of the first and second switching mechanisms. The first piston engages with the first engagement protrusion, and the first engagement. The second part that is not engaged with the protrusion is divided into two parts vertically.

  Accordingly, the first and second switching mechanisms switch the first and second pistons between the engaged position and the non-engaged position, and the first rocker arm is engaged with the first piston by the first engagement of the second rocker arm. When the protrusion is engaged, one of the intake valve and the exhaust valve is driven to open and close following the shape of the first cam for low speed, and the second engagement protrusion of the third rocker arm is engaged with the second piston. Sometimes, following the shape of the second cam for high speed, one of the intake valve and the exhaust valve is driven to open and close, and when the engagement projection is not engaged with any of the first and second pistons, the intake valve or the exhaust valve One of these is closed and the operation state of the internal combustion engine is switched according to the above switching.

  The first portion of the first piston engages with the first engagement protrusion every time the second rocker arm swings, and the entire first rocker arm is moved to inertial mass with the engagement of the first engagement protrusion. Therefore, mechanical properties different from those of the second portion not engaged with the first engagement protrusion are required. By dividing the first and third pistons into two parts, a first part and a second part, it is possible to apply a material according to each request to each part. In addition, it is possible to manufacture the first portion with a material that is not likely to be damaged, and to manufacture the second portion with a less expensive material.

According to a third aspect of the present invention, in the second aspect of the present invention, the control means includes a first mode in which the first rocker arm is driven by the first cam, a second mode in which the first rocker arm is driven by the second cam, And the switching of the first and second switching mechanisms is controlled so as to be in any one of the third modes in which the first rocker arm is inoperative.
Accordingly, in the first mode, the first rocker arm is driven by the first cam, and one of the intake valve and the exhaust valve is driven to open and close following the shape of the first cam. In the second mode, the first rocker arm is Driven by the second cam, one of the intake valve and the exhaust valve is driven to open and close following the shape of the second cam. In the third mode, the first rocker arm is deactivated and the intake valve or the exhaust valve is Keep one closed.

  According to a fourth aspect of the present invention, there is provided a first rocker arm whose tip is linked to one of the intake valve and the exhaust valve and is swingably supported on the first rocker shaft, and adjacent to one side of the first rocker arm. A second rocker arm that is swingably supported by one rocker shaft and driven by a first cam for low speed, and is pivotally supported by the first rocker shaft adjacent to the other side of the first rocker arm. The third rocker arm driven by the second cam for high speed and the tip of the third rocker arm are linked to the other of the intake valve or the exhaust valve, and can swing freely on the second rocker shaft arranged parallel to the first rocker shaft. A fourth rocker arm to be supported, a fifth rocker arm that is swingably supported on the second rocker shaft adjacent to the fourth rocker arm, and driven by a third cam, and a first rocker arm. First A first piston slidably mounted on the cylinder; a second piston slidably mounted on a second cylinder formed adjacent to the first cylinder on the first rocker arm; and a fourth rocker arm A third piston slidably mounted on the formed third cylinder; a first engagement protrusion extending from the second rocker arm and engagable with the first piston; and a third rocker arm A second engagement protrusion extending from the second piston so as to be engageable with the second piston, a third engagement protrusion extending from the fifth rocker arm and provided to be engageable with the third piston, A first, second, and third switching mechanism that switches the positions of the first, second, and third pistons between an engagement position and a non-engagement position with respect to the first, second, and third engagement protrusions, respectively; , Control for controlling switching of the first, second and third switching mechanisms The first and third pistons are vertically moved to a first part that engages with the first and third engaging protrusions and a second part that does not engage with the first and third engaging protrusions, respectively. It is divided into two.

  Accordingly, the first and second switching mechanisms switch the first and second pistons between the engaged position and the non-engaged position, and the first rocker arm is engaged with the first piston by the first engagement of the second rocker arm. When the projection is engaged, one of the intake valve and the exhaust valve is driven to open and close following the shape of the first cam for low speed, and when the second engagement projection of the third rocker arm is engaged with the second piston When one of the intake valve and the exhaust valve is driven to open and close following the shape of the second cam for high speed, and the engagement projection is not engaged with any of the first and second pistons, the intake valve or the exhaust valve Keep one closed.

  When the third piston is switched between the engaged position and the non-engaged position by the third switching mechanism, and the fourth rocker arm is engaged with the third piston and the third engagement protrusion of the fifth rocker arm. The other of the intake valve and the exhaust valve is driven to open and close following the shape of the third cam, and when the third engagement protrusion of the fifth rocker arm is not engaged with the third piston, the other of the intake valve or the exhaust valve is Hold the valve closed. Therefore, the operating state of the internal combustion engine is switched according to the above switching.

  The first portion of the first piston engages with the first engagement protrusion every time the second rocker arm swings, and the entire first rocker arm is moved to inertial mass with the engagement of the first engagement protrusion. The first portion of the third piston engages with the third engagement protrusion every time the fifth rocker arm swings, and the fourth portion is engaged with the engagement of the third engagement protrusion. Since the entire rocker arm is rocked against the inertial mass, mechanical properties different from those of the second portion not engaged with the first engagement protrusion or the third engagement protrusion are required. By dividing the first and third pistons into two parts, a first part and a second part, it is possible to apply a material according to each request to each part. For example, the first and third pistons are engaged with the first and third engaging protrusions. It is possible to manufacture the first portion with a material that does not break even if they are combined, and to manufacture the second portion with a less expensive material.

  According to a fifth aspect of the present invention, in the fourth aspect, the control means includes a first mode in which the first rocker arm is driven by the first cam and the fourth rocker arm is driven by the third cam. Any one of the second mode in which the rocker arm is driven by the second cam and the fourth rocker arm is driven by the third cam, and the third mode in which the first and fourth rocker arms are inoperative The switching of the first, second and third switching mechanisms is controlled so that

  Accordingly, in the first mode, the first rocker arm is driven by the first cam, and one of the intake valve and the exhaust valve is driven to open and close following the shape of the first cam, and the fourth rocker arm is in the third mode. Driven by the cam, the other of the intake valve and the exhaust valve is driven to open and close following the shape of the third cam. In the second mode, the first rocker arm is driven by the second cam, and either the intake valve or the exhaust valve is driven to open and close following the shape of the second cam, and the fourth rocker arm is driven by the third cam. Driven to open and close the other of the intake valve and the exhaust valve according to the shape of the third cam. In the third mode, the first and fourth rocker arms are deactivated to hold both the intake valve and the exhaust valve closed.

  According to a sixth aspect of the present invention, a tip end is linked to one of the intake valve and the exhaust valve, and is supported by a rocker shaft so as to be swingable and driven by a fourth cam, and adjacent to the sixth rocker arm. A rocker shaft supported by the rocker shaft and driven by a fifth cam having a cam shape different from that of the fourth cam, and a fourth rocker arm formed on one of the sixth and seventh rocker arms. A fourth piston slidably mounted on the cylinder, a fourth engagement protrusion extending from the other of the sixth or seventh rocker arm and engagable with the fourth piston, and a fourth piston A fourth switching mechanism that switches a position between an engagement position and a non-engagement position with respect to the fourth engagement protrusion; and a control unit that controls switching of the fourth switching mechanism. A first portion engaged with the mating protrusion, and a fourth engagement And a second portion not engaged with the protrusion is what is divided into two vertically.

  Accordingly, when the fourth switching mechanism switches the fourth piston between the engagement position and the non-engagement position, and the sixth rocker arm does not engage the fourth piston with the fourth engagement protrusion, the fourth cam When one of the intake and exhaust valves is driven to open and close following the shape of the valve, and the fourth engagement protrusion engages with the fourth piston, one of the intake and exhaust valves is opened and closed according to the shape of the fifth cam The operation state of the internal combustion engine is switched according to the above switching.

  The first portion of the fourth piston engages with the fourth engagement projection every time the seventh rocker arm swings, and the entire mass of the sixth rocker arm is inertial mass with the engagement of the fourth engagement projection. Therefore, mechanical properties different from those of the second portion that does not engage with the fourth engagement protrusion are required. By dividing the fourth piston into two parts, a first part and a second part, it becomes possible to apply a material according to each request to each part, for example, even if it is engaged with the fourth engagement protrusion, it is damaged. It is possible to manufacture the first portion with a material that has no fear and to manufacture the second portion with a less expensive material.

A seventh aspect of the invention is that in the first, second, fourth, and sixth aspects, the second portion is made of a material having lower rigidity than the first portion.
Therefore, the first portion of the piston is required to have higher rigidity than the second portion because it engages with the engaging protrusion and swings the entire rocker arm. However, a material having high rigidity is used for the first portion. In addition, since a material with lower rigidity, that is, an inexpensive material is used for the second portion, the manufacturing cost is reduced as compared with the case where the entire piston is manufactured with a material having high rigidity.

An eighth aspect of the present invention is that, in the first, second, fourth, and sixth aspects, the second portion is housed and slid in the corresponding cylinder, and is formed to have a smaller diameter than the first portion.
Therefore, for example, when the switching mechanism applies hydraulic pressure to the piston to switch between the engaged position and the non-engaged position, the piston switching is slowed if the second portion of the piston that receives the hydraulic pressure is excessively enlarged. Therefore, it is desirable to reduce the diameter of the second portion, while the first portion of the piston needs to have a certain diameter in order to securely engage the engaging protrusion of the corresponding rocker arm. However, by forming the second part with a smaller diameter than the first part, it is possible to satisfy the respective requirements for the first part and the second part.

As described above, according to the valve operating apparatus for an internal combustion engine of the first to seventh aspects of the present invention, troubles such as breakage of the piston for switching the operating state are prevented in advance and reliability is improved. The manufacturing cost can be reduced, and consequently the manufacturing cost of the entire valve gear can be reduced.
According to the valve operating apparatus for an internal combustion engine of the eighth aspect of the invention, in addition to the first, second, fourth, and sixth aspects, the piston can be quickly switched by reducing the diameter of the second portion, and operates with good responsiveness. The drivability can be improved by completing the switching of the state, and the engagement protrusion can be switched reliably by increasing the diameter of the first portion, and the reliability can be improved by switching the operating state reliably.

[First Embodiment]
Hereinafter, a first embodiment of an engine valve operating apparatus embodying the present invention will be described. In addition, this embodiment is corresponded to embodiment of Claim 1-5,7,8.
The engine of the present embodiment is configured as a V-type 6-cylinder gasoline engine having four valves per cylinder, and in particular, a high-speed mode that realizes a high engine output, a low-speed mode that corresponds to a normal engine output, and cylinders in one bank are rested. It is configured to be switchable between idle cylinder modes. For this reason, the valve gears of both banks are each provided with a switching mechanism between the low speed mode and the high speed mode, and in addition, the bank on one side is provided with a cylinder resting mechanism. Therefore, first, the configuration of a bank provided with a cylinder resting mechanism (hereinafter referred to as a cylinder resting bank and the opposite side as a non-cylinderless bank) will be described.

《Cylinder Bank》
1 to 8 show the cylinder heads of the idle cylinder bank, FIG. 1 is a plan view showing the cylinder head, FIG. 2 is a partially enlarged plan view showing details of a valve operating system for one cylinder, and FIG. FIG. 4 is a cross-sectional view showing when the low-speed cam and the exhaust cam corresponding to the AA line of FIG. 2 is a cross-sectional view showing the high-speed cam corresponding to the BB line in FIG. 2 when the high-speed cam is at rest, FIG. 6 is a cross-sectional view showing the high-speed cam corresponding to the BB line in FIG. FIG. 8 is a partial enlarged plan view showing a positional relationship between the driven rocker arm and FIG. Here, the top and bottom of FIG. 1 is the front-rear direction of the engine, the right side of the cylinder head corresponds to the intake side, the left side corresponds to the exhaust side, and the cylinder head of the non-cylinder bank is arranged to the right of the cylinder head And

  As shown in FIGS. 2, 3, and 7, one camshaft 2 of the valve operating device is disposed at a substantially right and left center on the cylinder head 1 so as to extend in the front-rear direction. Each journal portion 2a is supported by the head journal portion and is driven to rotate in synchronization with the crankshaft. An intake rocker shaft 3 (first rocker shaft) is disposed on the upper right side of the camshaft 2, and an exhaust rocker shaft 4 (second rocker shaft) is disposed on the upper left side of the camshaft 2, and these rocker shafts are disposed. 3 and 4 are fixed on the cylinder head 1 by bolts 5 in a posture parallel to the camshaft 2.

  Each cylinder is arranged in the front-rear direction along the camshaft 2, and hereinafter, a valve operating device for one cylinder will be described, but the other cylinders have the same configuration. As shown in FIG. 7, between a pair of adjacent journal portions 2a of the camshaft 2, a low-speed intake cam 6 (first cam, hereinafter abbreviated as a low-speed cam), an exhaust cam 7 ( A cam for one cylinder is formed in the order of a third cam), a rest cam 8, and a high speed side intake cam 9 (second cam, hereinafter abbreviated as a high speed cam). Hereinafter, the configuration of the intake side and exhaust side valve operating devices driven by these cams 6 to 9 and the configuration of the oil passage for switching the valve operating devices will be sequentially described.

<Intake side valve operating device>
As shown in FIGS. 2 and 3, a bearing hole 12 a formed in the boss portion 12 of the intake driven rocker arm 11 (first rocker arm) is fitted into the intake rocker shaft 3, and the intake driven rocker arm is centered on the intake rocker shaft 3. 11 as a whole can swing. Two valve-side arm portions 13 having a bifurcated shape extend from the boss portion 12 toward the right, and an adjustment bolt 14 for adjusting a valve clearance is provided at the tip of each valve-side arm portion 13. Each corresponds to an intake valve (not shown) on the cylinder head 1.

  As shown in FIGS. 7 and 8, one cam side arm portion 15 extends from the boss portion 12 toward the left, and the sliding contact portion 15 a formed at the tip of the cam side arm portion 15 has the above-mentioned rest. It abuts on the cam 8. When the intake driven rocker arm 11 swings clockwise from the state where the sliding contact portion 15a of the cam side arm portion 15 is in contact with the rest cam 8, the intake valve is moved via the adjustment bolt 14 of the valve side arm portion 13. The valve is opened against the valve spring. Hereinafter, the swinging direction of the members constituting the intake side valve operating device such as the intake driven rocker arm 11, the low-speed drive rocker arm 32 and the high-speed drive rocker arm 38, which will be described later, is opened in the clockwise direction and closed in the counterclockwise direction. Defined as direction.

  As shown in FIGS. 2, 3, and 5, a cylindrical low-speed cylinder portion 16 and a high-speed cylinder portion 17 are integrally provided on the boss portion 12 of the intake driven rocker arm 11. The low-speed cylinder portion 16 is formed with a small-diameter lower cylinder 16a (first and third cylinders) having a circular cross section and a large-diameter upper cylinder 16b (first and third cylinders) which are continuously formed in the vertical direction. The lower end of the cylinder 16a opens to the inner peripheral surface of the bearing hole 12a of the boss portion 12, and the upper end of the upper cylinder 16b opens upward.

  A lower piston 18a (first and third pistons, second portion) is disposed in the lower cylinder 16a, and the lower piston 18a is restricted from rotating around the axis of the lower cylinder 16a by a restriction pin (not shown). Thus, it can slide in the lower cylinder 16a in the vertical direction. An upper piston 18b (first and third pistons, first portion) is disposed in the upper cylinder 16b and can slide in the upper cylinder 16b in the vertical direction. The upper piston 18b is made of a material having higher rigidity and wear resistance than the lower piston 18a.

  A lid 19 is press-fitted into the opening of the upper cylinder 16b and is prevented from coming off by a snap ring 20. A compression spring 21 is interposed between the lid 19 and the upper piston 18b in the upper cylinder 16b. As shown in FIG. 3, the lower piston 18 a and the upper piston 18 b are always urged downward by the compression spring 21, and the lower piston 18 a is in a lower position where the lower surface of the lower piston 18 a is in contact with the outer peripheral surface of the intake rocker shaft 3. Is retained. As shown in FIG. 4, when the lower piston 18a and the upper piston 18b slide upward in the cylinders 16a and 16b against the compression spring 21 from the lower position, the upper portion of the upper piston 18b It contacts the lower part and is switched to the upper position.

  An operation window 22 is formed on the left side of the low speed cylinder 16, that is, the side facing the camshaft 2, while a relief 23 is recessed on the left side of the lower piston 18 a. In the upper position of the pistons 18a and 18b shown in FIG. 4, the escape portion 23 of the lower piston 18a is exposed to the left through the operation window 22, and in the lower position shown in FIG. Thus, the outer peripheral surface of the upper piston 18b is exposed to the left.

  On the other hand, as shown in FIG. 5, a cylinder 17a (second cylinder) having a circular cross section is formed in the high speed cylinder portion 17 in the vertical direction, and the lower end of the cylinder 17a is inside the bearing hole 12a of the boss portion 12. It opens to the peripheral surface, and the upper end of the cylinder 17a opens upward. A piston 25 (second piston) is disposed in the cylinder 17a, and the piston 25 slides up and down in the cylinder 17a in a state where the rotation about the axis of the cylinder 17a is restricted by a restriction pin (not shown). Can do. The diameter of the piston 25 is larger than the diameter of the lower piston 18a of the low-speed cylinder portion 16, and is set to be approximately equal to the diameter of the upper piston 18b. The same material as that of the upper piston 18b is applied to the piston 25, and equivalent rigidity is obtained. Is secured.

  Similar to the low-speed cylinder portion 16, a lid body 27 is fixed to the opening of the cylinder 17 a by a snap ring 26, and a compression spring 28 is interposed between the lid body 27 and the piston 25. As shown in FIG. 5, the piston 25 is always urged downward by the compression spring 28, and is held at a lower position where the lower surface is in contact with the outer peripheral surface of the intake rocker shaft 3. Further, as shown in FIG. 6, when the piston 25 slides upward in the cylinder 17a against the compression spring 28 from the lower position, the upper part of the piston 25 comes into contact with the lower part of the lid 27 and moves to the upper position. Switched.

  An operation window 29 is formed on the left side surface of the high-speed cylinder portion 17, while a relief portion 30 is recessed on the left side surface of the piston 25, and the operation window 29 is provided at a position below the piston 25 shown in FIG. The exposed portion 30 of the piston 25 is exposed to the left, and the outer peripheral surface of the piston 25 is exposed through the operation window 29 at the upper position shown in FIG. The compression spring 28 of the high-speed cylinder portion 17 has a smaller overall length than the compression spring 21 of the low-speed side cylinder 16, and has a long overall length so as to ensure a biasing force to the predetermined piston 25. It is disposed offset from the axis of the portion 17 and is held in a spring hole 25a formed on the piston 25 in order to prevent bending due to compression.

  On the other hand, as shown in FIGS. 2 and 3, a boss portion 33 of a low-speed drive rocker arm 32 (second rocker arm) is swingably supported on the front side of the intake driven rocker arm 11 on the intake rocker shaft 3. On the right side of the boss portion 33, a biasing portion 33a protrudes downward, and the entire low-speed drive rocker arm 32 is biased in the valve closing direction by a biasing spring (not shown) connected to the biasing portion 33a. As shown in FIG. 7, a roller 35 provided on the left side is brought into contact with the low-speed cam 6.

  From the upper position of the roller 35 of the low-speed drive rocker arm 32, the operation arm portion 36 (first and third engagement protrusions) extends rearward along the axis of the camshaft 2, and the tip of the operation arm portion 36 is on the right side. It is bent in an L shape toward the intake driven rocker arm 11 located on the side, and corresponds to the operation window 22 of the low speed cylinder portion 16. The low-speed drive rocker arm 32 swings following the shape of the low-speed cam 6 while rolling the roller 35 on the rotating low-speed cam 6, and in the base circle section of the low-speed cam 6 (section where the lift amount is 0), FIG. As shown by a solid line, the valve swings in the valve closing direction to disengage the tip of the operation arm 36 from the operation window 22 to the left and opens in the lift section of the low-speed cam 6 as shown by a two-dot chain line in FIG. The tip of the operation arm 36 is inserted into the operation window 22 by swinging in the valve direction.

  A boss portion 39 of a high-speed drive rocker arm 38 (third rocker arm) is swingably supported on the rear side of the intake driven rocker arm 11 on the intake rocker shaft 3, and is driven at high speed similarly to the low-speed drive rocker arm 32. The rocker arm 38 is urged in the valve closing direction by an urging spring (not shown) via an urging portion 39a, and a roller 40 provided on the left side is brought into contact with the high-speed cam 9 as shown in FIG. .

  From the upper position of the roller 40 of the high-speed drive rocker arm 38, the operation arm portion 41 (second engagement protrusion) extends forward along the axis of the camshaft 2, and the tip of the operation arm portion 41 is positioned on the right side. It is bent in an L-shape toward the intake driven rocker arm 11 and corresponds to the operation window 29 of the high-speed cylinder portion 17. Like the low-speed drive rocker arm 32, the high-speed drive rocker arm 38 swings following the shape of the high-speed cam 9 while rolling the roller 40 on the high-speed cam 9. In the base circle section of the high-speed cam 9, a solid line in FIG. As shown in FIG. 5, it swings in the valve closing direction to disengage the tip of the operation arm 41 to the left from the operation window 29, and in the lift section of the high-speed cam 9, in the valve opening direction as shown by a two-dot chain line in FIG. It swings and the tip of the operation arm 41 is inserted into the operation window 29.

<Exhaust valve operating device>
On the other hand, the exhaust-side valve operating device omits the high-speed cylinder portion 17 of the intake driven rocker arm 11 and the corresponding high-speed drive rocker arm 38 from the intake-side valve operating device, and the configuration will be described below.

  As shown in FIGS. 2 and 3, the exhaust rocker shaft 4 is fitted with a bearing hole 44 a of a boss portion 44 of an exhaust driven rocker arm 43 (fourth rocker arm), and the exhaust driven rocker arm 43 as a whole centering on the exhaust rocker shaft 4. Can swing. Two valve-side arm portions 45 having a bifurcated shape extend from the boss portion 44 toward the left, and the adjustment bolts 46 provided at the tips of the valve-side arm portions 45 are respectively provided on the cylinder head 1. This corresponds to an exhaust valve (not shown).

  As shown in FIG. 7, the boss portion 12 of the intake driven rocker arm 11 and the boss portion 44 of the exhaust driven rocker arm 43 are arranged on the left and right sides with the camshaft 2 interposed therebetween, and both boss portions in the axial direction of the camshaft 2. A part of 12, 44 is polymerized with each other. As shown in FIGS. 7 and 8, one cam side arm portion 47 extends rightward from the boss portion 44, and the sliding contact portion 47a formed at the tip of the cam side arm portion 47 It is in contact with the rest cam 8 while avoiding interference with the sliding contact portion 15a on the driven rocker arm 11 side.

  When the exhaust driven rocker arm 43 swings counterclockwise from this state, the exhaust valve is opened against the valve spring via the adjustment bolt 46 of the valve side arm portion 45. Hereinafter, the swinging direction of the members constituting the exhaust side valve operating device such as the exhaust driven rocker arm 43 and the exhaust driving rocker arm 49 described later is defined as the valve opening direction, and the clockwise direction as the valve closing direction.

2 and 3, a cylindrical cylinder portion 48 is integrally provided on the boss portion 44 of the exhaust driven rocker arm 43. As shown in FIG. 3, the cylinder portion 48 is on the intake driven rocker arm 11 side. The low-speed cylinder portion 16 has the same configuration that is symmetrical to the left and right.
Therefore, the same member number as that of the low-speed cylinder part 16 is attached and the cylinder part 48 is outlined. The lower piston 18a is provided in the lower cylinder 16a of the cylinder part 48, and the upper piston 18b is provided in the upper cylinder 16b. It is slidably arranged in the vertical direction. These pistons 18a and 18b are urged downward by the compression spring 21. At the lower position shown in FIG. 3, the lower surface of the lower piston 18a abuts against the outer peripheral surface of the exhaust rocker shaft 4, and the operation window 22 of the cylinder portion 48 is used. The outer peripheral surface of the upper piston 18b is exposed to the right, and the escape portion 23 of the upper piston 18a is exposed to the right from the operation window 22 at the upper position shown in FIG.

The members such as the lower piston 18 a, the upper piston 18 b, the lid 19, and the compression spring 21 that are housed in the exhaust-side cylinder portion 48 are shared with the members that are housed in the intake-side low-speed cylinder portion 16. It has become.
On the other hand, as shown in FIGS. 2 and 3, an exhaust drive rocker arm 49 (fifth rocker arm) is swingably supported on the front side of the exhaust driven rocker arm 43 on the exhaust rocker shaft 4, and the exhaust drive rocker arm 49 is inhaled. It has the same configuration symmetrical with respect to the low-speed drive rocker arm 32 on the side.

Therefore, when the same member number as the low-speed drive rocker arm 32 is attached and the outline of the exhaust drive rocker arm 49 is described, the exhaust drive rocker arm 49 is biased in the valve closing direction by a biasing spring (not shown) via the biasing portion 33a. Thus, the roller 35 provided on the right side is brought into contact with the exhaust cam 7. An operation arm portion 36 extends rearward from the exhaust drive rocker arm 49, and the distal end of the operation arm portion 36 is bent in an L shape toward the left side so as to be connected to the operation window 22 of the cylinder portion 48 of the exhaust driven rocker arm 43. It corresponds. The exhaust drive rocker arm 49 swings following the shape of the exhaust cam 7 while rolling the roller 35. In the base circle section of the exhaust cam 7, it swings in the valve closing direction as shown by the solid line in FIG. The tip of the arm portion 36 is moved to the right from the operation window 22, and in the lift section of the exhaust cam 7, the tip of the operation arm portion 36 is operated by swinging in the valve opening direction as shown by a two-dot chain line in FIG. Insert into window 22.
The description of the valve operating device for one cylinder of the cylinder deactivation bank is completed as described above, but the other cylinders have the same configuration as described above.

<Oil passage>
As shown in FIGS. 1 and 2, the intake rocker shaft 3 is formed with a cylinder resting mode oil passage 51 and a high speed mode oil passage 52 along the axial direction. Opening is made on the front end surface and the rear end surface of the shaft 3. The front end of the idle cylinder mode oil passage 51 is closed by a plug 53, and one end of an L-shaped metal pipe 54 is press-fitted and fixed to the rear end. The front end of the high-speed mode oil passage 52 is connected to a high-speed mode oil control valve 55 (hereinafter referred to as OCV) via an oil supply passage (not shown) formed in the cylinder head 1, and the rear end is a plug 56. It is blocked by.

  The exhaust rocker shaft 4 is formed with a cylinder resting mode oil passage 57 along the axial direction, and both front and rear ends of the oil passage 57 open to the front end surface and the rear end surface of the exhaust rocker shaft 4. The front end of the idle cylinder mode oil passage 57 is connected to the idle cylinder mode OCV 58 via an oil supply passage (not shown) formed in the cylinder head 1, and one end of an L-shaped metal pipe 59 is press-fitted and fixed to the rear end. Has been. The other ends of the intake-side and exhaust-side metal pipes 54 and 59 face each other at a predetermined interval, and both ends of a rubber hose 60 are fitted and connected to each other.

The OCVs 55 and 58 for the high speed mode and the cylinder deactivation mode are supplied with oil from a lubricating oil pump (not shown) provided in the engine, while being controlled by an ECU 61 (control means, abbreviated as an engine control unit) mounted on the vehicle. By switching control, oil is appropriately supplied to the high-speed mode oil passage 52 and the idle cylinder mode oil passage 57.
As shown in FIGS. 2 and 3, the intake rocker shaft 3 is formed with communication paths 63 at three locations (one location is shown in the figure) so as to correspond to the low speed cylinder portion 16 of the intake driven rocker arm 11 of each cylinder. The lower end of each communication passage 63 communicates with the cylinder resting mode oil passage 51, and the upper end of each communication passage 63 opens to the outer peripheral surface of the intake rocker shaft 3 and communicates with the inside of the lower cylinder 16 a of each low speed cylinder portion 16. Yes.

  As shown in FIGS. 2 and 5, the intake rocker shaft 3 is formed with communication passages 64 at three locations (one location is shown in the figure) so as to correspond to the intake driven rocker arm 11 and the high speed cylinder portion 17 of each cylinder. The lower end of each communication passage 64 communicates with the high-speed mode oil passage 52, and the upper end of each communication passage 64 opens to the outer peripheral surface of the intake rocker shaft 3 and communicates with the inside of the cylinder 17 a of each high-speed cylinder portion 17.

  As shown in FIGS. 2 and 3, the exhaust rocker shaft 4 is formed with communication passages 65 at three locations (one location is shown in the figure) so as to correspond to the cylinder portion 48 of the exhaust driven rocker arm 43 of each cylinder. The lower end of each communication passage 65 communicates with the cylinder resting mode oil passage 57, and the upper end of each communication passage 65 opens to the outer peripheral surface of the exhaust rocker shaft 4 to communicate with the inside of the lower cylinder 16 a of each cylinder portion 48. Yes.

  Here, in the present embodiment, the first cylinder for switching the lower piston 18a and the upper piston 18b of the low-speed cylinder portion 16 of the intake driven rocker arm 11 by the cylinder mode oil passage 51, the cylinder mode OCV 58, and the communication path 63. A switching mechanism is configured, and the second switching mechanism for switching the piston 25 of the high-speed cylinder portion 17 of the intake driven rocker arm 11 is configured by the high-speed mode oil passage 52, the high-speed mode OCV 55, and the communication passage 64, and the cylinder-rest mode A third switching mechanism for switching the lower piston 18a and the upper piston 18b of the cylinder portion 48 of the exhaust driven rocker arm 43 is configured by the oil passage 57, the cylinder rest mode OCV 58, and the communication passage 65.

《Non-cylinder bank》
On the other hand, the valve operating device of the non-cylinder bank does not include a cylinder resting mechanism but includes only a switching mechanism between the low speed mode and the high speed mode. Specifically, on the intake side, the low-speed cylinder portion 16 and the low-speed drive rocker arm 32 of the intake driven rocker arm 11 are omitted (the high-speed cylinder portion 17 and the high-speed drive rocker arm 38 remain), and the intake driven rocker arm 11 is left. Oscillates directly by the low-speed cam 6 without passing through the low-speed drive rocker arm 32 and always drives the intake valve to open and close.

  On the exhaust side, the cylinder portion 48 and the exhaust drive rocker arm 49 of the exhaust driven rocker arm 43 are omitted, and the exhaust driven rocker arm 43 swings directly by the exhaust cam 7 without passing through the exhaust drive rocker arm 49 and is always exhausted. Open / close drive. Since the intake and exhaust driven rocker arms 11 and 43 always swing in this manner, the rest cam 8 of the camshaft 2 is also omitted. Further, with the omission of the cylinder deactivation mechanism, the cylinder deactivation mode oil passages 51 and 57 of the intake rocker shaft 3 and the exhaust rocker shaft 4 are also omitted.

Next, the operation state of the valve gear for an engine configured as described above will be described.
The switching control of the OCVs 55 and 58 by the ECU 61 is performed based on the engine rotational speed Ne. For example, in the rotational range where the engine rotational speed Ne is less than the first threshold value Ne1 and the output request to the engine is sufficiently low, the idle cylinder mode is executed. The low speed mode is executed in the rotational range where the normal engine output is required between the first threshold Ne1 and the second threshold Ne2 (> Ne1), and a particularly high engine output is required above the second threshold Ne2. The high speed mode is executed in the rotation range. Therefore, the operation status of the valve operating device will be described sequentially for each mode.

<Low speed mode>
In the idle cylinder, the ECU 61 switches and controls the high speed mode OCV 55 and the idle cylinder mode OCV 58 to stop the oil supply to the idle cylinder mode oil passage 51 and the high speed mode oil passage 52, respectively.

  As a result, as shown in FIG. 3, the lower piston 18a and the upper piston 18b are held at the lower positions by the urging force of the compression spring 21 in the low-speed cylinder portion 16 of the intake driven rocker arm 11 and the cylinder portion 48 of the exhaust driven rocker arm 43, respectively. Thus, the outer peripheral surface of the upper piston 18 b is exposed through the operation window 22. Further, as shown in FIG. 5, in the high speed cylinder portion 17 of the intake driven rocker arm 11, the piston 25 is held at the lower position by the urging force of the compression spring 28, and the escape portion 30 is exposed through the operation window 29. .

On the other hand, during operation of the engine, the low-speed drive rocker arm 32, the high-speed drive rocker arm 38, and the exhaust drive rocker arm 49 always swing according to the shapes of the corresponding cams 6, 7, and 9, and each operation arm portion 36 is accompanied by the swing. , 41 are inserted into and removed from the operation windows 22, 29 of the driven rocker arms 11, 43.
The high-speed drive rocker arm 38 is swung by itself while inserting and removing the tip of the escape portion 30 exposed from the operation window 29 of the high-speed cylinder unit 17 and is driven like the low-speed drive rocker arm 32 and the exhaust drive rocker arm 49 described below. The rocker arms 11 and 43 are not swung.

  Further, the low-speed drive rocker arm 32 and the exhaust drive rocker arm 49 respond by pressing the outer peripheral surface of the upper piston 18b exposed from the operation window 22 of the low-speed cylinder unit 16 and the cylinder unit 48 when swinging in the valve opening direction. The driven rocker arms 11 and 43 are swung in the valve opening direction to open the intake valve and the exhaust valve. Further, when the low-speed drive rocker arm 32 and the exhaust drive rocker arm 49 are swung in the valve closing direction, the corresponding driven rocker arms 11 and 43 are swung in the valve closing direction due to the urging force of the valve spring accompanying the valve closing of the intake / exhaust valve. Move.

As a result, the intake driven rocker arm 11 swings together with the low-speed drive rocker arm 32 to drive the intake valve to open and close following the shape of the low-speed cam 6, and the exhaust driven rocker arm 43 swings together with the exhaust drive rocker arm 49 to The exhaust valve is driven to open and close following the shape.
On the other hand, in the non-cylinder bank, the ECU 61 stops the oil supply to the high-speed mode oil passage 52 by the high-speed mode OCV 55, so that the high-speed drive rocker arm 38 swings in the same manner as the idle cylinder bank, following the shape of the low-speed cam 6. Thus, the intake valve is driven to open and close, and the exhaust valve is driven to open and close following the shape of the exhaust cam 7. Therefore, in this low speed mode, the engine output required in the normal rotation range is realized using the low speed cam 6 and the exhaust cam 7.

<Cylinder mode>
In the idle cylinder bank and the non-vacuum bank, the ECU 61 supplies oil by the idle cylinder mode OCV 58 in the idle cylinder bank while stopping the oil supply to the high-speed mode oil passage 52.

  Oil from the idle cylinder mode OCV 58 circulates in the idle cylinder mode oil passage 57 of the exhaust rocker shaft 4 from the front side to the rear side, and is supplied into the lower cylinder 16 a of the exhaust driven rocker arm 43 through the respective communication paths 65. Further, after passing through the metal pipes 54 and 59 and the hose 60, the intake rocker shaft 3 circulates in the cylinder resting mode oil passage 51 from the rear side to the front side, passes through the communication passages 63, and the intake driven rocker arm 11. It is supplied into the lower cylinder 16a.

  In the lower cylinder 16 a and the upper cylinder 16 b of the intake driven rocker arm 11 and the exhaust driven rocker arm 43, the lower piston 18 a and the upper piston 18 b slide upward while receiving the oil pressure of the supplied oil and resisting the compression spring 21. The position is switched to the upper position, and the escape portion 23 of the lower piston 18 a is exposed through the operation window 22. Therefore, the low-speed drive rocker arm 32 and the exhaust drive rocker arm 49 are swung independently while inserting and detaching the tip from the escape portion 23 exposed from the operation window 22 of the corresponding driven rocker arm 11, 43, and swinging with respect to each driven rocker arm 11, 43. Cancel the operation.

Since the high-speed drive rocker arm 38 is also swung as described above, as a result, the intake and exhaust valves are held closed by the urging force of the valve spring in each cylinder of the idle cylinder, and the intake driven rocker arm 11 and the exhaust driven rocker arm 43 are The sliding contact portions 15a and 47a of the cam-side arms 15 and 47 are held at the valve-closing position in a state where the cam-side arms 15 and 47 are in contact with the rest cam 8.
On the other hand, in the non-cylinder bank, the operation of each cylinder is continued in the same manner as in the low speed mode, and the operation of the vehicle is continued by the torque generated in the bank and This saves fuel consumption.

<High-speed mode>
In the idle cylinder bank, the ECU 61 stops supplying oil to the idle cylinder mode oil passage 51 by the idle cylinder mode OCV 58 and supplies oil to the high speed mode oil passage 52 by the high speed mode OCV 55.

As a result, as in the low speed mode, the outer peripheral surface of the upper piston 18 b is exposed through the operation window 22 in the low speed cylinder portion 16 of the intake driven rocker arm 11 and the cylinder portion 48 of the exhaust driven rocker arm 43.
On the other hand, oil in the high-speed mode oil passage 52 is supplied into the cylinder 17a of the high-speed cylinder portion 17 in the intake driven rocker arm 11 of each cylinder through the communication passage 64. In the cylinder 17 a, the oil pressure of the supplied oil is received and the piston 25 slides upward against the compression spring 28 and is switched to the upper position, and the outer peripheral surface of the piston 25 is exposed through the operation window 29.

As a result, on the exhaust side, as in the low speed mode, the exhaust driven rocker arm 43 swings together with the exhaust drive rocker arm 49 following the shape of the exhaust cam 7, and the exhaust valve is driven to open and close following the shape of the exhaust cam 7.
On the intake side, the pistons 18b and 25 of the low-speed cylinder unit 16 and the high-speed cylinder unit 17 are both exposed and can be pressed by the corresponding drive rocker arms 32 and 38. Since the cam 9 has a wider lift section (that is, operating angle) and a larger lift amount, the actual pressing operation is performed on the high-speed drive rocker arm 38 side, and the low-speed drive rocker arm 32 is swung. That is, in this high speed mode, the intake valve is driven to open and close following the shape of the high speed cam 9.

On the other hand, as with the non-cylinder bank, oil is supplied to the high-speed mode oil passage 52 in the non-cylinder bank, and the intake valve is driven to open and close following the shape of the high-speed cam 9. Therefore, in the high speed mode, a high engine output required in a high rotation range is realized by increasing the valve opening period and the lift amount of the intake valve as compared with the low speed mode.
The valve operating apparatus for the engine according to this embodiment operates as described above. In this embodiment, as described above, the low-speed cylinder portion 16 of the intake driven rocker arm 11 and the piston of the cylinder portion 48 of the exhaust driven rocker arm 43 are divided into two vertically as a lower piston 18a and an upper piston 18b. The upper piston 18b is made of a material having higher rigidity and wear resistance than the lower piston 18a, and the effects of the configuration will be described in detail below.

Compared with the lower piston 18a that mainly receives hydraulic pressure, the upper piston 18b is pressed by the operating arm portion 36 of the low speed and exhaust drive rocker arms 32 and 49, and the driven rocker arms 11 and 43 as a whole resist the inertial mass. Therefore, high rigidity is required because of rocking, and high wear resistance is also required because the tip of the operation arm portion 36 collides with each rocking.
When the lower piston 18a and the upper piston 18b are manufactured integrally, it is necessary to manufacture the whole piston with an expensive material (for example, a material subjected to carburizing and quenching) so as to satisfy the characteristics required for the upper piston 18b. However, in this embodiment, an expensive material is applied only to the upper piston 18b, and a cheaper material (for example, a material that is not carburized and quenched) can be applied to the lower piston 18a. Therefore, after preventing troubles such as breakage of the upper piston 18b and improving the reliability of the valve operating device, the manufacturing cost of the piston of each driven rocker arm 11, 43, and thus the manufacturing cost of the entire valve operating device can be reduced. Can be reduced.

Further, since the lower piston 18a and the upper piston 18b are divided into two parts and the diameter of the lower piston 18a is reduced with respect to the upper piston 18b, the following effects can be obtained.
First, since the oil for switching the pistons 18a, 18b, 25 of the intake and exhaust driven rocker arms 11, 43 is supplied from the engine oil pump, sufficient oil discharge is possible in the low engine speed range where the pump rotational speed is reduced. The amount cannot be expected. Therefore, although the piston 25 is quickly switched in the high speed cylinder portion 17 of the intake driven rocker arm 11 under a sufficient oil discharge amount in the high rotation range (second threshold value Ne2), the low speed cylinder portion 16 of the intake driven rocker arm 11; In the cylinder portion 48 of the exhaust driven rocker arm 43, the piston is switched under a low oil discharge amount in the low rotation range (first threshold value Ne1).

Here, since it is the lower piston 18a that actually receives the hydraulic pressure in each of the cylinder portions 16 and 48, it is desirable to reduce the diameter of the lower piston 18a in order to achieve good switching response.
On the other hand, the upper piston 18b needs to secure a certain diameter due to the following factors. First, in the low-speed cylinder portion 16 and the cylinder portion 48 in which the lower piston 18a has a small diameter, the piston 25 inevitably has no room for offset arrangement of the compression spring 28 unlike the high-speed cylinder portion 17 having a large diameter. Is disposed above the upper piston 18b. In order to urge the upper piston 18b downward, the diameter or length of the compression spring 21 is required to some extent, but the method of extending the spring length is to move the cylinder portion 16, upward from the rotation center of the driven rocker arms 11, 43. 48 greatly protrudes, which increases the inertial mass of the valve gear and leads to an increase in engine height. Therefore, a method of enlarging the spring diameter is adopted, and it is necessary to increase the diameter of the upper piston 18b according to the spring diameter.

  The low-speed and exhaust drive rocker arms 32 and 49 are required to have a predetermined pressing stroke to open the intake and exhaust valves via the intake and exhaust driven rocker arms 11 and 43, and the driven rocker arm 11 and The clearance 23 of the lower piston 18a 43 needs to have a depth (left and right dimensions in FIG. 3) that can avoid the pressing stroke. Further, since the lower piston 18a requires a sufficient thickness even after the relief portion 23 is formed, in order to satisfy these requirements of the pressing stroke, the depth of the relief portion 23, and the thickness, in the valve opening direction. The swinging drive rocker arms 32 and 49 must be brought into contact with the upper piston 18b on the front side, and the upper piston 18b must be increased in diameter.

  By setting the diameters of the lower piston 18a and the upper piston 18b as described above, the requirements for the pistons 18a and 18b can be satisfied. That is, by reducing the diameter of the lower piston 18a, even if the oil supply into the lower cylinder 16a is slow due to insufficient oil pump discharge, the lower piston 18a can be quickly slid to the upper position. The drivability can be improved by completing the switching from the low speed mode to the non-cylinder mode with responsiveness. Further, by increasing the diameter of the upper piston 18b, it is possible to prevent the increase of the inertia mass of the valve operating device and the engine height by enlarging the spring diameter, and at the same time, the low speed and exhaust drive rocker arms 32, 49 with sufficient pressing stroke. Thus, the upper piston 18b can be pushed to reliably switch from the idle cylinder mode to the low speed mode, thereby improving the reliability.

  On the other hand, the configuration in which the pistons 18a and 18b are divided into two parts vertically has an advantage in that the pistons 18a and 18b slide smoothly. That is, when such different-diameter pistons are integrated, it is necessary to form the individual cylinders 16a and 16b corresponding to the piston diameter in a state where the axes of the pistons coincide with each other, and machining is very difficult. Therefore, it is difficult to maintain the expected tolerance. As a result, the piston clearance tends to increase, and oil leakage occurs in the lower piston 18a and sliding failure due to galling occurs in the upper piston 18b. When the upper and lower pistons 18a and 18b are divided as in the present embodiment, the cylinders 16a and 16b need only be formed in accordance with the piston diameter, and the axes of both the cylinders 16a and 16b need not be aligned. Machining is facilitated, the desired piston clearance is achieved, the above-mentioned problems can be prevented, and smooth piston sliding can be realized. This factor also contributes to improving the reliability of the valve operating device.

[Second Embodiment]
Next, a second embodiment in which the present invention is embodied in another engine valve gear will be described. This embodiment corresponds to the embodiments of claims 6-8.
The valve operating apparatus of this embodiment omits the cylinder resting mechanism from the valve operating apparatus of the first embodiment, and includes only a switching mechanism between the low speed mode and the high speed mode. Therefore, on the basis of the configuration of the idle cylinder bank of the first embodiment, common portions are denoted by the same member numbers, and only a brief description is given, and differences will be mainly described.

  9 is a partially enlarged plan view showing details of the valve operating device for one cylinder of the engine of the present embodiment, FIG. 10 is a partially enlarged plan view showing the positional relationship between the drive rocker arm and the driven rocker arm with respect to the cam, and FIG. It is sectional drawing which shows the time of the action | operation of the low speed cam corresponded to the DD line.

<Intake side valve operating device>
The intake driven rocker arm 11 (sixth rocker arm) supported by the intake rocker shaft 3 has a cam side arm portion 101 extending leftward, and cams a roller 102 provided at the tip of the cam side arm portion 101. The shaft 2 is brought into contact with the low speed cam 6 (fourth cam). The intake driven rocker arm 11 swings following the shape of the low speed cam 6 while rolling the roller 102 on the low speed cam 6, and opens and closes an intake valve (not shown) via the valve side arm portion 13.

  The intake driven rocker arm 11 is provided with a high-speed cylinder portion 103, and this high-speed cylinder portion 103 has the same configuration as the low-speed cylinder portion 16 of the first embodiment. That is, a lower piston 18a (fourth piston, second portion) is provided in the lower cylinder 16a (fourth cylinder) of the high-speed cylinder portion 103, and an upper piston 18b (fourth cylinder) is provided in the upper cylinder 16b (fourth cylinder) in the high-speed cylinder portion 103. The fourth piston and the first portion are slidably arranged in the vertical direction. The lower piston 18a and the upper piston 18b are always urged downward by the compression spring 21. At the lower position where the lower surface of the lower piston 18a is in contact with the outer peripheral surface of the intake rocker shaft 3, the lower piston 18a and the upper piston 18b are In the upper position where the escape portion 23 of the lower piston 18a is exposed leftward and slides upward against the compression spring 21 from this lower position, the outer peripheral surface of the upper piston 18b is left via the operation window 22. Exposed to the direction.

Also in this embodiment, the upper piston 18b is made of a material having a larger diameter than that of the lower piston 18a and having high rigidity and wear resistance.
A high-speed drive rocker arm 38 (seventh rocker arm) is slidably supported on the rear side of the intake driven rocker arm 11 on the intake rocker shaft 3, and the high-speed drive rocker arm 38 is urged in the valve closing direction by an urging spring (not shown). Thus, the roller 40 provided on the left side is brought into contact with the high-speed cam 9 (fifth cam) of the camshaft 2. The high-speed drive rocker arm 38 swings in accordance with the shape of the high-speed cam 9 while rolling the roller 40 on the high-speed cam 9, and accordingly, the operation arm portion 41 (fourth engagement protrusion) is operated on the high-speed cylinder portion 103. Insert into and remove from the window 22.

<Exhaust valve operating device>
The exhaust rocker arm 105 supported by the exhaust rocker shaft 4 has a cam side arm portion 106 extending rightward, and a roller 107 provided at the tip of the cam side arm portion 106 is placed on the exhaust cam 7 of the cam shaft 2. It is made to contact. The exhaust rocker arm 105 swings following the shape of the exhaust cam 7 while rolling the roller 107 on the exhaust cam 7, and opens and closes an exhaust valve (not shown) via the valve side arm portion 108.

<Oil passage>
A high speed mode oil passage 52 is formed in the intake rocker shaft 3, and the high speed mode oil passage 52 communicates with the high speed cylinder portion 103 of the intake driven rocker arm 11 of each cylinder via a communication passage 64. The front end of the high-speed mode oil passage 52 is connected to the high-speed mode OCV 55, and the high-speed mode OCV 55 is switched and controlled by the ECU 61 (control means).

Here, in the present embodiment, the fourth switching mechanism for switching the lower piston 18a and the upper piston 18b of the high-speed cylinder portion 103 of the intake driven rocker arm 11 by the high-speed mode oil passage 52, the high-speed mode OCV 55, and the communication passage 64. Is configured.
Next, the operation state of the valve gear for an engine configured as described above will be described.

<Low speed mode>
In both the non-cylinder bank and the non-cylinder bank, the ECU 61 supplies oil to the high-speed mode oil passage 52 by the high-speed mode OCV 55. As a result, as shown in FIG. 11, in the high-speed cylinder portion 103 of the intake driven rocker arm 11, the lower piston 18a and the upper piston 18b are held at the upper positions, the escape portion 23 is exposed from the operation window 22, and the high-speed drive rocker arm 38 is While the tip is inserted into and removed from the escape portion 23, it is swung away. Therefore, the intake driven rocker arm 11 swings by the low speed cam 6 to open and close the intake valve following the shape of the low speed cam 6, while the exhaust rocker arm 105 is driven by the exhaust cam 7.

<High-speed mode>
In both the non-cylinder bank and the non-cylinder bank, the ECU 61 stops the oil supply to the high-speed mode oil passage 52 by the high-speed mode OCV 55. As a result, in the high-speed cylinder portion 103 of the intake driven rocker arm 11, the lower piston 18a and the upper piston 18b are switched to the lower position, and the high-speed drive rocker arm 38 presses the outer peripheral surface of the upper piston 18b exposed from the operation window 22. Therefore, the intake driven rocker arm 11 swings together with the high-speed drive rocker arm 38 to open and close the intake valve following the shape of the high-speed cam 9, while the exhaust rocker arm 105 is driven by the exhaust cam 7 as in the low-speed mode.

  Although the operational effects obtained by the above configuration are the same as those in the first embodiment, they will not be described in detail. However, an expensive material is applied only to the upper piston 18b of the high-speed cylinder unit 103 that requires high rigidity and wear resistance. Thus, since an inexpensive material is applied to the lower piston 18a, the manufacturing cost of the piston of the intake driven rocker arm 11 is improved after preventing troubles such as breakage of the upper piston 18b and improving the reliability of the valve operating device. As a result, the manufacturing cost of the entire valve gear can be reduced.

  In addition, since the diameter of the lower piston 18a is smaller than that of the upper piston 18b, the lower piston 18a can be quickly slid upward to complete the switching from the high speed mode to the low speed mode with good responsiveness. By increasing the diameter of the upper piston 18b, the upper piston 18a can be pressed by the high-speed drive rocker arm 38 with a sufficient pressing stroke, and the switching from the low speed mode to the high speed mode can be performed reliably.

This is the end of the description of the embodiment, but the aspect of the present invention is not limited to this embodiment. For example, in each of the above-described embodiments, the present invention is applied to a V-type 6-cylinder gasoline engine having four valves per cylinder. However, the type and form are not limited to this. For example, the present invention is applied to a diesel engine, or two valves per cylinder are connected in series. It may be applied to the engine.
In the first embodiment, the valve gear is configured to be switchable between the low speed mode, the high speed mode, and the idle cylinder mode (configuration of claim 4). For example, the high speed cylinder portion 17 and the high speed of the intake driven rocker arm 11 are configured. The drive rocker arm 38 is omitted (that is, the configuration of claim 1 in which the switching function to the high speed mode is omitted), the cylinder portion 48 of the exhaust driven rocker arm 43 and the exhaust drive rocker arm 49 are omitted (that is, the exhaust side rocker arm is closed). The configuration of claim 2 in which the function of switching to the cylinder mode is omitted.

It is a top view which shows the cylinder head with which the valve operating apparatus of the engine of 1st Embodiment was provided. It is a partial enlarged plan view which shows the detail of the valve operating apparatus for 1 cylinder. It is sectional drawing which shows the time of the action | operation of the low speed cam corresponding to the AA line of FIG. 2, and an exhaust cam. It is sectional drawing which shows the time of a low-speed cam and exhaust cam corresponding to the AA line of FIG. FIG. 3 is a cross-sectional view showing when the high-speed cam corresponding to line BB in FIG. 2 is at rest. It is sectional drawing which shows the time of the action | operation of the high-speed cam equivalent to the BB line of FIG. It is a partial enlarged plan view which shows the positional relationship of the drive rocker arm with respect to a cam, and a driven rocker arm. It is CC sectional view taken on the line of FIG. It is a partial enlarged plan view which shows the detail of the valve operating apparatus for 1 cylinder of the engine of 2nd Embodiment. It is a partial enlarged plan view which shows the positional relationship of the drive rocker arm with respect to a cam, and a driven rocker arm. It is sectional drawing which shows the time of the action | operation of the low speed cam corresponding to the DD line | wire of FIG.

Explanation of symbols

3 Intake rocker shaft (first rocker shaft)
4 Exhaust rocker shaft (second rocker shaft)
6 Low speed cam (1st and 4th cam)
7 Exhaust cam (third cam)
9 High-speed cams (second and fifth cams)
11 Intake driven rocker arm (first and sixth rocker arms)
16a Lower cylinder (first, third and fourth cylinder)
16b Upper cylinder (first, third and fourth cylinder)
17a Cylinder (second cylinder)
18a Lower piston (first, third and fourth pistons, second part)
18b Upper piston (first, third and fourth pistons, first part)
25 piston (second piston)
32 Low-speed drive rocker arm (second rocker arm)
36 Operation arm portion (first and third engaging protrusions)
38 High-speed drive rocker arms (third and seventh rocker arms)
41 Operation arm portion (second and fourth engagement protrusions)
43 Exhaust driven rocker arm (fourth rocker arm)
49 Exhaust drive rocker arm (fifth rocker arm)
51 Oil passage for closed cylinder mode (first switching mechanism)
52 Oil passage for high speed mode (second and fourth switching mechanism)
55 OCV for high speed mode (2nd and 4th switching mechanism)
57 Oil passage for closed cylinder mode (third switching mechanism)
58 OCV for idle cylinder mode (first and third switching mechanism)
61 ECU (control means)
63 Communication path (first switching mechanism)
64 communication path (second and fourth switching mechanisms)
65 communication path (third switching mechanism)

Claims (8)

A first rocker arm whose tip is linked to one of an intake valve or an exhaust valve and is pivotally supported on the first rocker shaft;
A second rocker arm that is swingably supported by the first rocker shaft adjacent to the first rocker arm and driven by a first cam;
A fourth rocker arm whose tip is linked to the other of the intake valve or the exhaust valve and is swingably supported by a second rocker shaft disposed in parallel with the first rocker shaft;
A fifth rocker arm that is swingably supported on the second rocker shaft adjacent to the fourth rocker arm and driven by a third cam;
A first piston slidably mounted on a first cylinder formed on the first rocker arm;
A third piston slidably mounted on a third cylinder formed on the fourth rocker arm;
A first engagement protrusion extending from the second rocker arm and provided to be engageable with the first piston;
A third engagement protrusion extending from the fifth rocker arm and provided to be engageable with the third piston;
First and third switching mechanisms for switching the positions of the first and third pistons between an engagement position and a non-engagement position with respect to the first and third engagement protrusions, respectively.
Control means for controlling switching of the first and third switching mechanisms,
The first and third pistons are vertically divided into a first part engaging with the first and third engaging protrusions and a second part not engaging with the first and third engaging protrusions, respectively. A valve operating apparatus for an internal combustion engine, characterized by being divided. A first rocker arm whose tip is linked to one of the intake valve or the exhaust valve and is pivotally supported on the rocker shaft;
A second rocker arm that is swingably supported on the rocker shaft adjacent to one side of the first rocker arm and driven by a first cam for low speed;
A third rocker arm that is swingably supported on the rocker shaft adjacent to the other side of the first rocker arm and is driven by a second cam for high speed;
A first piston slidably mounted on a first cylinder formed on the first rocker arm;
A second piston slidably mounted on a second cylinder formed adjacent to the first cylinder on the first rocker arm;
A first engagement protrusion extending from the second rocker arm and provided to be engageable with the first piston;
A second engagement protrusion extending from the third rocker arm and provided to be engageable with the second piston;
First and second switching mechanisms for switching the positions of the first and second pistons between an engagement position and a non-engagement position with respect to the first and second engagement protrusions, respectively;
Control means for controlling switching of the first and second switching mechanisms,
The internal combustion engine is characterized in that the first piston is vertically divided into a first part that engages with the first engagement protrusion and a second part that does not engage with the first engagement protrusion. Engine valve gear.   The control means includes: a first mode in which the first rocker arm is driven by the first cam; a second mode in which the first rocker arm is driven by the second cam; and the first rocker arm 3. The valve operating apparatus for an internal combustion engine according to claim 2, wherein switching of the first and second switching mechanisms is controlled so as to be in any one of the third modes that are inactive. A first rocker arm whose tip is linked to one of an intake valve or an exhaust valve and is pivotally supported on the first rocker shaft;
A second rocker arm that is swingably supported on the first rocker shaft adjacent to one side of the first rocker arm and is driven by a first cam for low speed;
A third rocker arm that is swingably supported by the first rocker shaft adjacent to the other side of the first rocker arm and is driven by a second cam for high speed;
A fourth rocker arm whose tip is linked to the other of the intake valve or the exhaust valve and is swingably supported by a second rocker shaft disposed in parallel with the first rocker shaft;
A fifth rocker arm that is swingably supported on the second rocker shaft adjacent to the fourth rocker arm and driven by a third cam;
A first piston slidably mounted on a first cylinder formed on the first rocker arm;
A second piston slidably mounted on a second cylinder formed adjacent to the first cylinder on the first rocker arm;
A third piston slidably mounted on a third cylinder formed on the fourth rocker arm;
A first engagement protrusion extending from the second rocker arm and provided to be engageable with the first piston;
A second engagement protrusion extending from the third rocker arm and provided to be engageable with the second piston;
A third engagement protrusion extending from the fifth rocker arm and provided to be engageable with the third piston;
First, second, and third switching mechanisms that switch the positions of the first, second, and third pistons between an engagement position and a non-engagement position with respect to the first, second, and third engagement protrusions, respectively. When,
Control means for controlling switching of the first, second and third switching mechanisms,
The first and third pistons are vertically divided into a first part engaging with the first and third engaging protrusions and a second part not engaging with the first and third engaging protrusions, respectively. A valve operating apparatus for an internal combustion engine, characterized by being divided.   The control means includes: a first mode in which the first rocker arm is driven by the first cam and the fourth rocker arm is driven by the third cam; and the first rocker arm is the second rocker. The mode is one of a second mode in which the fourth rocker arm is driven by the cam and the fourth rocker arm is driven by the third cam, and a third mode in which the first and fourth rocker arms are inoperative. 5. The valve operating apparatus for an internal combustion engine according to claim 4, wherein switching of the first, second and third switching mechanisms is controlled as described above. A sixth rocker arm whose tip is linked to one of the intake valve or the exhaust valve, is pivotably supported by the rocker shaft, and is driven by a fourth cam;
A seventh rocker arm that is swingably supported on the rocker shaft adjacent to the sixth rocker arm and is driven by a fifth cam having a different cam shape from the fourth cam;
A fourth piston slidably mounted on a fourth cylinder formed on one of the sixth or seventh rocker arms;
A fourth engagement protrusion extending from the other of the sixth or seventh rocker arm and provided to be engageable with the fourth piston;
A fourth switching mechanism that switches a position of the fourth piston between an engagement position and a non-engagement position with respect to the fourth engagement protrusion;
Control means for controlling the switching of the fourth switching mechanism,
The internal combustion engine is characterized in that the fourth piston is vertically divided into two parts: a first part that engages with the fourth engagement protrusion and a second part that does not engage with the fourth engagement protrusion. Engine valve gear.   The valve operating device for an internal combustion engine according to any one of claims 1, 2, 4, and 6, wherein the second portion is made of a material having lower rigidity than the first portion.   The said 2nd part is accommodated and slid by the said corresponding cylinder, and is formed in the diameter smaller than the said 1st part, The any one of Claim 1, 2, 4, 6 characterized by the above-mentioned. A valve operating apparatus for an internal combustion engine as described.

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