JPS6038008Y2 - Valve stop mechanism - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a valve operation stop mechanism that stops the operation of poppet valves used particularly in intake valves, exhaust valves, etc. of automobile engines.

In a multi-cylinder engine, depending on the operating condition, for example, when idling or under low load, it is not necessary to operate all cylinders, so in order to save fuel consumption, the intake and exhaust valves of some cylinders are stopped and the cylinder is switched off. Consideration is being given to activating all cylinders by activating the intake and exhaust valves again depending on the operating state.

The mechanism for operating and stopping the above-mentioned intake and exhaust valves is, for example, a stopper driven by an actuator that uses engine oil pressure, which engages and disengages from a plunger that is slidably installed in a part of the valve train. A mechanical valve stop mechanism is being considered.

In such a multi-cylinder engine, when starting, it is necessary to operate all cylinders to ensure startability, and therefore the stopper must be engaged with the plunger by the actuator.

In this case, with a valve actuation stop mechanism that engages the stopper with the plunger when hydraulic pressure is supplied to the actuator, the stopper and plunger do not fully engage due to insufficient engine oil pressure at the time of startup, and the There is a problem in which the exhaust valve cannot operate and the engine enters a cylinder operation state, resulting in extremely poor starting performance.

In order to solve this problem, it is possible to use a pump that generates sufficient oil pressure even at startup, but there is a problem in that the viscosity of the oil becomes extremely large at extremely low temperatures, making it impossible to obtain sufficient oil pressure.

The present invention was proposed in view of the above, and is a plunger that is slidably installed in a part of a valve train that drives poppet valves used in engine intake valves, exhaust valves, etc., and that the plunger is detachable. The plunger is provided in the engagement position to restrict the sliding movement of the plunger to allow the poppet valve to be driven by the action of the valve train, and to put the poppet valve into the operating state, and the plunger is in the disengaged position. A stopper that allows the plunger to slide and stops the poppet valve from being driven by the action of the valve train, thereby rendering the poppet valve inoperative; a hydraulic actuator for moving the engagement position or the disengagement position; an oil pump driven by the engine; a hydraulic pressure supply means for supplying hydraulic pressure generated by the oil pump to the hydraulic actuator;
a hydraulic pressure switching means provided in the hydraulic pressure supply means for operating the actuator by switching between supplying and cutting off the supply of hydraulic pressure to the hydraulic actuator; The stopper is provided with a command means for issuing a command signal for switching between supplying and cutting off the supply of hydraulic pressure to the actuator, and the position of the stopper is such that the position of the stopper provides a state of the poppet valve that is suitable for an engine operating state in which the hydraulic pressure generated by the oil pump is low. The gist of the present invention is to provide a valve operation stop mechanism that is configured to be activated when the supply of hydraulic pressure to the hydraulic actuator is cut off.

According to the above configuration, the stopper engages with the plunger when the hydraulic pressure supply to the hydraulic actuator is cut off, so even when starting the engine when sufficient hydraulic pressure is not generated, the intake and exhaust valves are reliably operated and all cylinders are operated. This can solve the problems mentioned above.

Hereinafter, one embodiment of the present invention will be described in detail with reference to the accompanying drawings.

In FIGS. 1 to 3, a rocker arm 10, which is part of a valve train for driving a poppet valve 12 used for an engine's intake valve, exhaust valve, etc., is a rocker shaft 14.
A cylinder 18 is attached to the end of the arm 16 on the right side of FIG. 1, and the arm 2 on the left side of FIG.
0 comes into contact with a cam (not shown) at its end.

A cylindrical plunger 22 with a bottom is slidably fitted into the cylinder 18 , and a screw 24 is inserted into the cylinder 18 .
A spring 28 interposed between a spring retainer 26 fixed to the bottom surface of the plunger 22 and the bottom surface of the plunger 22 presses the plunger 22 downward in FIGS. It is brought into contact with the end of the valve shaft of No. 12.

Slots 30 and 32 formed in the right arm 16 and plunger 22, respectively, across the cylindrical wall of the cylinder 18.
A semicircular key 34 extending within these arms,
Relative rotation between the cylinder and plunger is prevented.

Two elongated holes 36 are provided in the cylindrical wall of the cylinder 18 at positions directly above the upper end of the plunger 22 when the plunger 22 is at the lowest position relative to the cylinder 18 (the position shown in the figure). As shown in FIG.
is now inserted.

The two-pronged fork portion of the stopper 38 has a cylindrical inner edge with a diameter slightly larger than the outer diameter of the plunger 22 on the left side, and a cylindrical shape with a diameter slightly larger than the outer diameter of the plunger 22 on the right side.
are spaced apart from each other by a distance approximately equal to the inner diameter of the two.

The rocker arm 10 is provided with a hydraulic actuator 44 that is separated from a cylinder 40 and a piston 42 that slides within the cylinder.

One end of a rod 46 is fitted into the piston 42, and a return spring 48 is interposed between the flange at one end of the rod 46 and the bottom surface of the cylinder 40 to press the piston 42 and rod 46 to the left in FIG. At the same time, they are kept connected.

The other end of the rod 46 is bifurcated, and the left end of the stopper 38 is accommodated between the legs of the fork.
6 and an oval slot 52 formed in the stopper 38 through which the pin 50 passes, the stopper 38 and the rod 46 are connected with a gap 54 along the sliding direction of the stopper. ing.

A timing plate 58 is pivotally supported on one side of the rocker arm 10 on a pivot shaft 56 extending through the rocker arm 10 at one end, and has a locking portion 60 extending over the rod 46 at the other end. The portion 60 engages with the right end surface of the rod 46 when the rod 46 is in the leftmost position shown in FIGS. 1 and 2, and engages with the right end surface of the rod 46 when the rod 46 is moved to the rightmost position.
6 can be engaged with a recess 62 formed in 6.

The timing plate 58 has at its center a protrusion 66 that engages with a timing cam 64 formed by scraping off a portion of the outer circumferential surface of the rocker shaft 14 along its circumferential direction.

This protrusion 66 constitutes a timing cam follower that causes the timing plate 58 to swing by the timing cam 64 in accordance with the swing of the rocker arm 10.

The other end of the leaf spring 68 , whose one end is fixed to the cylinder 18 with the screw 24 , contacts the locking portion 60 of the timing plate 58 and presses the locking portion downward, while also engaging the protruding portion 66 with the timing cam 64 . It is working to make it happen.

Further, an elongated portion 70 extending downward along the cylinder 18 is provided at one end of the leaf spring 68, and the elongated portion engages with the lower surface of the stopper 38 and presses the stopper 38 upward. Prevents vibration.

The cylinder 40 of the actuator 44 is connected to the shaft in the rocker shaft 14 through an oil passage 72 provided in the rocker arm 10 and a supply oil passage 74 provided in the radial direction of the rocker shaft 14, regardless of the swinging of the rocker arm 10. It is always in communication with the oil passage 76 in the direction.

The oil passage 76 is connected to a hydraulic source P such as an engine oil pump via a hydraulic switching device 78.
The operation is 0N-OF of the engine ignition switch.
It is controlled by a computer 80 which receives a large amount of information regarding F-states and other operating conditions of the engine.

The operation of the above-mentioned valve operation stop mechanism will be explained.

1 to 3 show a state in which the hydraulic switching device 78 cuts off hydraulic communication from the pressure source P to the oil passage 76 due to the operation of the computer 80.

In this state, no hydraulic pressure is supplied to the hydraulic actuator 44, the piston 42 and the rod 46 are at the leftmost position due to the pressing force of the return spring 48, and the stopper 38 is also moved to the leftmost position and the plunger is moved to the leftmost position. It is engaged with the upper end of 22.

As a result, when a cam lift occurs and the rocker arm 10 is swung, the plunger 22 cannot slide within the cylinder 18, so the poppet valve 12 is actuated.

From this state, in order to stop the operation of the poppet valve 12 according to the operating state of the engine, when the computer 80 operates the hydraulic pressure switching device 78 to supply hydraulic pressure from the hydraulic source P to the oil passage 76, the hydraulic pressure changes. The piston 42 and rod 46 are communicated with the cylinder 40 of the actuator 44 through oil passages 74 and 72 to push the piston 42 and rod 46 to the right in FIG. 1 against the return spring 48. Since the locking portion 60 of the plate 58 engages with the right end surface of the rod 46, the piston 42 and rod 46 cannot slide to the right.

Next, when the cam lift occurs and reaches or is close to the maximum value, the rocker arm 10 rotates clockwise, and the protrusion 66 of the timing plate 58 follows the timing cam 64, causing the timing plate 58 to move backward around the pivot shaft 56. Since the timing plate is rotated clockwise, the locking portion 60 of the timing plate is disengaged from the right end surface of the rod 46, and the piston 42 and rod 46 are slid to the right by hydraulic pressure.

However, in this state, the rocker arm 10 swings and operates the poppet valve 12 before the engagement is released, so the stopper 38 is connected to the upper end of the plunger 22 and the elongated hole 36.
It cannot slide because it is clamped between it and the top surface of the valve by the valve spring load.

Therefore, the piston 42 and the rod 46 slide by the size of the gap 54 provided at the connecting portion with the stopper 38, and are brought to a position where the right end surface of the rod 46 and the locking portion 60 of the timing plate 58 do not engage.

Thereafter, when the cam lift is completed, the stopper 38 is released from the valve spring load and becomes slidable, so that as the piston 42 and rod 46 move to the right due to hydraulic pressure, the inner edge of the two-pronged fork portion of the stopper 38 is removed from the elongated hole 36, and the plunger 22 can swing.

As a result, even if the next cam lift occurs and the rocker arm 10 swings, the plunger 22 swings relative to the cylinder 18, so the poppet valve 12 is not operated.

In this state, the locking portion 60 of the timing plate 58 is engaged with the recess 62 of the rod 46 when no cam lift is occurring.

To reactivate the poppet valve 12 depending on engine operating conditions, the computer 80 activates the hydraulic switching device 78 to drain the hydraulic pressure in the actuator 44 via the oil passages 72, 74 and 76, and the return spring 48 The rod 46 and the piston 42 are pushed to the left, but the locking portion 60 of the timing plate 58 is engaged with the recess 62 of the rod 46 during a period when no cam lift is occurring, so the rod 46 is pushed to the left. It cannot be slid in either direction.

When the cam lift is at or near the maximum value, the counterclockwise rotation of the timing plate 58 disengages the engagement between the locking portion 60 and the recess 62 of the rod 46, so that the rod 46 and piston 42 are moved to the return spring. It is moved to the left by the pressing force of 48.

However, in this state, the cam lift occurs and the rocker arm 10 is oscillated, and the plunger 22 is slid inside the cylinder 18. Therefore, the stopper 38 is attached to the inner edge of the fork portion of the plunger 22. It cannot slide due to hitting the cylinder wall surface.

Therefore, the piston 42 and the rod 46 slide by the size of the gap 54 provided at the connection portion with the stopper 38, and the position is reached where the locking portion 60 of the timing plate and the recess 62 do not engage.

After that, when the cam lift is completed, the plunger 22
is slid downward outside the cylinder 18 by the pressing force of the spring 28, and its upper end is located below the elongated hole 36, so that the stopper 38 becomes slidable, and the left side of the piston 42 and the rod 46 are moved by the return spring 48. As the stopper 38 moves in the opposite direction, the inner edge of the two-pronged fork portion of the stopper 38 opens into the elongated hole 36.
The upper end of the plunger 22 is abutted against the upper end of the plunger 22, thereby preventing the plunger 22 from sliding.

As a result, the next time a cam lift occurs and the rocker arm 10 is swung, the plunger 22 cannot slide relative to the cylinder 18, so the poppet valve 12 is actuated.

As described above, the valve actuation/stopping mechanism according to the present invention is configured so that the poppet valve is actuated when the hydraulic pressure supply to the hydraulic actuator is cut off. When the above-mentioned valve operation stop mechanism is used in a multi-cylinder engine in which the cylinder is closed by stopping operation, even when starting the engine when insufficient hydraulic pressure is generated or at extremely low temperatures, the hydraulic pressure supply to the actuator is cut off. All cylinders can be operated by operating the intake and exhaust valves via the valve operation stop mechanism, and good startability can be maintained.

In the above embodiment, the computer 80 controls the hydraulic pressure switching device 78, for example, a three-way solenoid valve, in response to the ON-OFF state of the ignition switch and the engine operating state. It is important to configure the solenoid valve to operate to supply hydraulic pressure to the actuator when the computer does not generate output current, and to discharge hydraulic pressure from the actuator when the computer does not generate output current.

If the solenoid valve is configured to supply hydraulic pressure to the actuator when the computer does not generate an output N flow, the actuator may remain in the hydraulic pressure supply state when the ignition switch is turned off.
Afterwards, if the oil is left for a long time in a particularly cold region and the viscosity of the oil becomes extremely large, the valve operation stop mechanism will become stuck in the state where the poppet valve operation has stopped, and even if the engine is started in this state, Since all cylinders are not activated, starting performance becomes very poor.

However, with the above configuration, the computer does not generate output current when the ignition switch is OFF, so the actuator's oil pressure is reliably discharged and the poppet valve is always in the operating state. Therefore, when the engine starts, it is reliable. This allows all cylinders to be activated to maintain good starting performance.

[Brief explanation of the drawing]

Figure 1 shows the line I-- in Figure 2 of the valve operation stop mechanism according to the present invention.
2 is a sectional view taken along line 1--2 in FIG. 1, and FIG. 3 is a sectional view taken along line 2--2 in FIG. 10... Rocker arm, 12... Poppet valve, 14... Middle shaft, 18... Cylinder, 22... Plunger, 38...
・Stopper, 42...Piston, 44...
...Hydraulic actuator, 46...Rod, 4
8... Return spring, 58... Timing plate, 64... Timing cam, 6
8...Plate spring, 78...Hydraulic switching device, 80...Computer.

Claims (1)

[Scope of utility model registration request] A plunger that is slidably installed in a part of the valve train that drives poppet valves used in engine intake valves, exhaust valves, etc., and when the plunger is detachably connected to the plunger and is in the engaged position. The sliding of the plunger is restricted to allow the poppet valve to be driven by the action of the valve train, and the poppet valve is activated, and the plunger is allowed to slide when the poppet valve is in the disengaged position. a stopper that stops the driving of the poppet valve by the action of the valve train and puts the poppet valve in an inoperative state; a hydraulic actuator for moving the hydraulic actuator, an oil pump driven by the engine, a hydraulic pressure supply means for supplying the hydraulic pressure generated by the oil pump to the hydraulic actuator, and a hydraulic pressure supply means provided in the hydraulic pressure supply means for supplying and supplying hydraulic pressure to the hydraulic actuator. Hydraulic switching means for switching the cutoff and operating the actuator, and
comprising command means for obtaining operating state information of the engine and issuing a command signal to the hydraulic pressure switching means for switching between supplying and cutting off the supply of hydraulic pressure to the hydraulic actuator;
The stopper is configured such that the position of the stopper that provides a state of the poppet valve suitable for an engine operating state in which the oil pressure generated by the oil pump is low is obtained when the supply of oil pressure to the hydraulic actuator is cut off. A valve operation stop mechanism featuring: