JP2009209879A - Valve gear for internal combustion engine, and hydraulic lash adjuster using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydraulic lash adjuster comprising a lift switch mechanism miniaturized and reduced in inertia mass. <P>SOLUTION: A plunger 24 is slidably provided inside of an upper part of a seat member 22 pressed into a body 21 for fixation, and a reservoir chamber 23 is provided inside the seat member, and a high-pressure chamber 25, of which volume is variable through a check valve 32, is formed in the body on the bottom side thereof. A piston 34 provided inside the plunger freely to slide in the radial direction is moved forward by the oil pressure inside a pressure receiver chamber 41, and engaged with the through-hole 38 so as to lock the plunger with the body, and while removed from the through-hole by spring force of springs 35 and 36 for lost motion of the whole of the plunger so as to stop operation of an intake valve 8. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a valve operating apparatus capable of adjusting a valve lift amount of an engine valve of an internal combustion engine for an automobile, for example, using a hydraulic lash adjuster and an improvement of the hydraulic lash adjuster.

  2. Description of the Related Art As is well known, various valve gears including a lift switching mechanism that switches valve lift amounts of an intake valve and an exhaust valve of an internal combustion engine according to an engine operating state are provided. There is one described in Document 1.

  The valve operating apparatus includes a camshaft that is rotationally driven by a crankshaft, a rocker arm that has one end abutting against the intake valve and transmits the rotational force of the drive cam of the camshaft to the intake valve, and the other end of the rocker arm. And a pivot for swingably supporting.

  The pivot is provided with a bottomed cylindrical body slidably provided in a bottomed cylindrical housing fixed in a holding hole of the cylinder head, and a tip portion is provided in the body. A plunger protruding from the upper end opening is provided slidably. In addition, a high-pressure chamber into which hydraulic pressure is introduced via a check valve is provided in the lower part of the body, and an engagement with which a connecting pin of a lift switching mechanism can be engaged with a lower part of the outer peripheral wall of the body. Grooves are formed.

  Between the housing and the body, a lost motion spring that urges the body upward is mounted.

  The lift switching mechanism is composed of the connecting pin provided so as to be able to advance and retreat from a casing provided in the cylinder head, and hydraulic means for moving the connecting pin forward and backward by hydraulic pressure.

Then, according to the vertical position of the body, the connecting pin is engaged with the engaging groove by hydraulic pressure to hold the plunger at the maximum upper position, thereby increasing the lift of the intake valve, while the connecting pin is retracted. The main constituent members such as the body and the plunger perform the lost motion against the spring force of the lost motion spring to control the lift of the intake valve to the zero state. It has become.
Japanese translation of PCT publication No. 2004-522885

  However, in the conventional valve operating apparatus, the entire pivot is moved largely in the vertical direction via the lost motion spring at the lower part of the pivot. At the same time, the inertial mass during the lost motion becomes large. As a result, fuel consumption and output torque may be deteriorated.

  The present invention has been devised in view of the technical problem of the conventional valve gear, and the invention according to claim 1 includes a camshaft that is driven to rotate by a crankshaft, and an engine valve that has one end. And a rocker arm that transmits the rotational force of the drive cam of the camshaft to the engine valve, and supports the other end of the rocker arm in a swingable manner, and a gap between the engine valve and one end of the rocker arm. The hydraulic lash adjuster for zero adjustment is provided, and a lift switching mechanism for switching a valve lift amount of the engine valve in accordance with an engine operating state is provided inside the hydraulic lash adjuster.

  According to a second aspect of the present invention, the hydraulic pressure is such that the other end portion of the rocker arm whose one end portion is in contact with the engine valve is swingably supported, and the clearance between the one end portion of the rocker arm and the engine valve is zero-adjusted. The lash adjuster is characterized in that a lift switching mechanism for switching a valve lift amount of the engine valve in accordance with an engine operating state is provided in the main body of the hydraulic lash adjuster.

  According to the present invention, the main components such as the piston of the lift switching mechanism are accommodated and disposed inside the hydraulic lash adjuster, and when the connection by the piston is released, the entire hydraulic lash adjuster is removed as in the prior art. Since only the plunger is slid instead of the lost motion, the entire apparatus can be miniaturized and the inertial mass can be reduced. As a result, since the friction of the valve operating device can be reduced, deterioration of fuel consumption and output torque can be suppressed.

  Hereinafter, embodiments of a valve operating apparatus and a hydraulic lash adjuster for an internal combustion engine according to the present invention will be described in detail with reference to the drawings.

  The internal combustion engine 1 is, for example, an in-line four-cylinder reciprocating engine, and the cylinder to which the hydraulic lash adjuster of the present invention is applied is applied to two cylinders such as a first cylinder and a third cylinder. ing.

  That is, in the internal combustion engine 1, as shown in FIG. 2, a crankshaft 4 is rotatably supported by a bearing outside the figure in a crank chamber 3 separated by a crankcase 2a of a cylinder block 2. A piston 6 connected to the crankshaft 4 via a connecting rod 5 is slidably provided inside a cylindrical cylinder wall 2b formed at the top of the crankcase 2a.

  An intake valve 8 and an exhaust valve 9 for opening and closing the intake port 7a and the exhaust port 7b, respectively, are slidably provided on the cylinder head 7 provided at the upper end of the cylinder wall 2b, and a drive provided on the outer periphery. An intake side camshaft 10 and an exhaust side camshaft 11 for opening the intake and exhaust valves 8 and 9 via cams 10a and 11a are rotatably supported by bearings (not shown). A rocker cover 20 is provided on the top of the cylinder head 7.

  The intake / exhaust valves 8 and 9 are urged in the closing direction by valve springs 12 and 13, and the rotational force of the drive cams 10 a and 11 a is converted into a swinging motion via the rocker arms 14 and 15. The valve is opened.

  Each of the rocker arms 14 and 15 has rollers 16 and 17 which are rotatably provided at the center thereof and are in rolling contact with outer peripheral surfaces of the drive cams 10a and 11a, and one end portion of each of the intake and exhaust valves 8 and 9 The other end is in contact with the hydraulic lash adjusters 18 and 19 so that the whole oscillates with the hydraulic lash adjusters 18 and 19 as swing fulcrums.

  As shown in FIGS. 1 and 3, the hydraulic lash adjuster 18 is press-fitted and fixed in a holding hole 7 c formed in the upper end portion of the cylinder head 7 along the vertical direction for convenience. A bottomed cylindrical body 21, a bottomed cylindrical sheet member 22 slidably provided inside the body 21 and having a reservoir chamber 23 therein, and an upper end portion of the sheet member 22. A high-pressure member that is slidably provided and is separated between a plunger 24 having a front end portion 24b protruding from an upper end opening of the sheet member 22, and an inner bottom portion of the body 21 and a bottom partition wall 22a of the sheet member 22. A chamber 25 and a main switching member are housed in the body 21, and a lift switching mechanism that locks the plunger 24 in the advanced position or releases the lock according to the engine operating state. It is provided with a 6, a.

  The body 21 is integrally formed of an iron-based metal, and a disc plate-like stopper member 27 having a through hole 27a in the center is attached to the upper end opening, and the length of the stopper 21 is the length of the holding hole 7c. It is formed slightly longer than the depth, and the upper end edge slightly protrudes from the holding hole 7c. The stopper member 27 is configured to hold the constituent members such as the sheet member 22 and the plunger 24 in the body 21 so that they do not jump out to the outside. The body 21 is formed with an oil hole 21a extending in the radial direction so as to communicate with the inside at a substantially central position of the peripheral wall.

  The seat member 22 is set to have an axial length substantially the same as an internal axial length of the body 21, and communicates the reservoir chamber 23 and the high-pressure chamber 25 with the partition wall 22 a on the bottom side. A passage 28 is formed through therethrough. A cylindrical separator 29 is fixed to the upper end surface of the partition wall 22a along the vertical direction. The separator 29 separates bubbles mixed in the hydraulic oil in the reservoir chamber 23 to separate the high pressure chamber. This prevents the inflow of bubbles to 25.

  The seat member 22 is biased upward by a return spring 31 that is elastically mounted between the inner bottom surface of the body 21 and the lower surface of the partition wall 22a.

  Further, the seat member 22 has an annular groove groove 22b formed at a position facing the oil hole 21a of the body 21 on the outer peripheral surface, and the substantially central position in the width direction of the groove groove 22b is the oil groove 21b. A communication hole 22c that connects the hole 21a and the reservoir chamber 23 is formed to penetrate in the radial direction. The reservoir chamber 23 is supplied with hydraulic oil discharged from an oil pump, which will be described later, from the oil supply passage 30 through the hydraulic pressure 21a, the groove groove 22b, and the communication hole 22c.

  A check valve 32 is provided in the high pressure chamber 25 to allow only hydraulic oil to flow from the reservoir chamber 23 to the high pressure chamber 25 via the communication passage 28. The check valve 32 is a ball valve body. 32a, a relief spring 32b that urges the ball valve body 32a in the closing direction of the communication passage 28, and a cup-shaped retainer 32c that holds the relief spring 32b.

  The plunger 24 is formed of a ferrous metal in a stepped diameter shape, and has a lower cylindrical large-diameter portion 24a that slides on the inner peripheral surface of the sheet member 22, and an upper side from the upper end surface of the large-diameter portion 24a. And a tip 24c of the small diameter portion 24b is formed in a spherical shape that comes into contact with a spherical contact surface 14a formed on the lower surface of the other end of the rocker arm 14. ing.

  Air bubbles mixed in the hydraulic oil in the reservoir chamber 23 are discharged to the inside of the plunger 24, that is, from the inside of the large diameter portion 24a to the inside of the small diameter portion 24b and the inside center of the tip portion 24c. Air discharge holes 24e are continuously formed.

  The lift switching mechanism 26 includes a sliding hole 33 formed in the large-diameter portion 24 a of the plunger 24 along a direction perpendicular to the axis, and a piston slidably provided in the sliding hole 33. 34, a pair of springs 35 and 36 which are biasing means for holding the piston 34 in a substantially neutral position in the sliding direction, and a position corresponding to the sliding hole 33 of the seat member 22, A guide long groove 37 that allows the piston 34 to slide in the vertical direction, and a slit that is formed in the upper end portion of the guide long groove 37 in a radial direction so that the front end portion 34b of the piston 34 can pass through and slide. A through hole 38 that is a joint, a lost motion spring 40 that is elastically loaded in the reservoir chamber 23 to urge the plunger 24 upward, and a rear end of the piston 34 A hydraulic circuit 42 for supplying and discharging oil pressure to the pressure receiving chamber 41 has been made, and a.

  The piston 34 has a large-diameter sliding contact portion 34a whose outer peripheral surface is in sliding contact with the inner peripheral surface of the sliding hole 33 on the outer periphery on the rear end side, and is disposed in front of and behind the sliding contact portion 34a. Further, the distal end portion 34b is held in the neutral position with the distal end portion 34b being disposed in the guide long groove 37 by the spring force of the pair of springs 35, 36. Further, the hydraulic pressure supplied to the pressure receiving chamber 41 moves forward, and the tip end portion 34b engages with the through hole 38 to lock the plunger 24 in the raised position.

  One side of the one side spring 35 is in elastic contact with one side surface of the sliding contact portion 34 a and the other side is a side surface of an annular plate-like retainer 43 fitted and fixed to the opening edge of the sliding hole 33. The piston 34 is urged to the right in the drawing. On the other hand, one end of the spring 36 on the other side is in elastic contact with the inner surface on the other end side of the sliding hole 33, and the other end is in elastic contact with the other side surface of the sliding contact portion 34a to urge the piston 34 to the left in the figure. is doing. Accordingly, the piston 34 is held at the neutral position by the spring force of the springs 35 and 36 facing each other.

  The hydraulic circuit 42 includes oil holes 21b, 22d, and 24d that are formed in the upper peripheral wall of the body 21, the upper peripheral wall of the seat member, and the large-diameter portion 24a of the plunger 24 and communicate with the pressure receiving chamber 36, respectively, The oil pump 46 that sucks hydraulic oil from 44 and discharges it to the supply passage 45, and the supply / discharge of one end connected to the oil hole 21b and the other end connected to an electromagnetic switching valve 47 that is a flow path switching valve. A passage 48, a drain passage 49 connected to the electromagnetic switching valve 47, and an electronic controller 50 (ECU) that operates the electromagnetic switching valve 47 are provided.

  The electromagnetic switching valve 47 is a three-port two-position type, and communicates the supply passage 45 and the supply / exhaust passage 48 with a control current output from the electronic controller 50, or a supply / exhaust passage 48 and a drain passage 49. Switch to communicate.

  The electronic controller 50 detects the current engine operating state based on detection signals from various sensors such as a crank angle sensor, an air flow meter, an engine water temperature sensor, a throttle opening sensor, and an accelerator opening sensor that are not shown in the figure, Based on this engine operating state, the control current is not output or output to the electromagnetic switching valve 47 on and off.

  Hereinafter, the operation of the present embodiment will be described. First, for example, when the engine is idling or when the engine is running at a low speed such as low speed, no control current is output from the electronic controller 50 to the electromagnetic switching valve 47. The hydraulic oil discharged from the exhaust gas is not supplied to the pressure receiving chamber 41 through the supply / discharge passage 48.

  For this reason, as shown in FIGS. 1 and 4, the piston 34 is held at a substantially neutral position in the axial direction by the spring force of both springs 35, 36, so that the tip 34 b is in the guide long groove 37. The guide groove 37 can be moved up and down. Therefore, in the lift region of the drive cam 10 a of the camshaft 10, the plunger 24 moves downward against the spring force of the lost motion spring 40 and does not transmit the lift force to the intake valve 8 via the rocker arm 14. The lost motion operation of the plunger 24 is performed by discharging the hydraulic oil in the reservoir chamber 23 from the air discharge hole 24e by the downward movement when the piston 24 is lowered.

  For this reason, the intake valve 8 of the two cylinders is in the valve stop state, and the intake valves 8 of the other two cylinders perform the opening / closing operation, so that it is possible to improve fuel efficiency while securing a certain amount of engine torque.

  In the base circle region of the drive cam 10a, the plunger 24 slightly rises so that the pressure receiving chamber 41 side 24d communicates with the oil holes 21b and 22d.

  Next, when the engine shifts to a steady operation, a control current is output from the electronic controller 50 to the electromagnetic switching valve 47 to connect the supply passage 45 and the supply / discharge passage 48 and close the drain passage 49.

  Therefore, for example, in the base circle region of the drive cam 10a, the hydraulic pressure is supplied from the oil hole 24d to the pressure receiving chamber 41 through the oil holes 21b and 22d from the supply / discharge passage 48, and the pressure receiving chamber 41 is not at a high pressure. Then, the piston 34 moves to the left in the figure against the spring force of one spring 35.

  For this reason, as shown in FIG. 5, the tip 34 b of the piston 34 is engaged in the through hole 38 of the body 21. As a result, the plunger 24 is locked to the seat member 22 via the piston 34 at the normal raised position. For this reason, the rocker arm 14 can swing about the plunger 24 as a swing fulcrum and can open each intake valve 8 by the lift force in the lift region of the drive cam 10a. Therefore, the two cylinders that have been in the valve stopped state also operate normally, and a sufficient torque of the engine can be secured.

  Further, when the engine operating state shifts to a low rotation range such as idling operation, as described above, the control current is not output from the electronic controller 50 to the electromagnetic switching valve 47, the flow path is switched and the supply passage 45 is switched. At the same time, the supply / discharge passage 48 and the drain passage 49 are communicated, and the hydraulic oil in the pressure receiving chamber 41 is returned to the oil pan 44 through the oil holes and the passages 48 and 49, and the pressure receiving chamber 41. The inside becomes low pressure. As a result, the piston 34 is moved backward in the right direction in the drawing by the spring force of one spring 35 and returned to the neutral position, and the tip end portion 34 b comes out of the through hole 38 and is positioned in the guide long groove 37. Accordingly, the plunger 24 is released from the locked state with the seat member 22, and the intake valves 8 are brought into a valve stop state as described above.

  The plunger 24 in the valve stop state is supplied with hydraulic oil from the oil supply passage 30 into the reservoir chamber 23 when the plunger 24 slightly moves up in the base circle region, and passes through the check valve 32 when the plunger 24 moves down. Since hydraulic oil is introduced into the high pressure chamber 25, the gap between the tip 24c and the contact surface 14a at the other end of the rocker arm 14 is absorbed, and one end of the rocker arm 14 and the stem end of the intake valve 8 are Adjust the valve clearance to zero.

  As described above, in this embodiment, not only can the valve clearance of the intake valve 8 be adjusted to zero by the hydraulic lash adjuster 18, but also main components such as the piston 34 of the lift switching mechanism 26 are used as the hydraulic lash adjuster. Since the lift switching mechanism 26 is not accommodated in the up-down direction because it is accommodated and disposed in the interior 18, the overall size can be reduced.

  In addition, when the connection between the seat member 22 and the plunger 24 by the piston 34 is released, the entire hydraulic rascia adjuster is not lost as in the prior art, but only the plunger 24 is lost. Therefore, the inertial mass can be sufficiently reduced. As a result, since the friction of the valve operating device can be reduced, deterioration of fuel consumption and output torque can be suppressed.

  Further, even if bubbles are generated in the reservoir chamber 23 due to the expansion and contraction operation of the lost motion spring 40, the bubbles are quickly discharged to the outside from the air discharge hole 24e by the gas-liquid separation action of the separator 29. Since the flow into the chamber 25 can be sufficiently prevented, the zero-lash adjustment can always be performed with high accuracy.

  The present invention is not limited to the above-described embodiment, and the internal combustion engine can be applied to any internal combustion engine other than four cylinders, for example, in-line or V-type six cylinders or eight cylinders. In addition to the coil spring, other spring members such as a disc spring can be used as the neutral urging member of the piston 34.

  In addition to the intake valve, the present invention can be applied to an exhaust valve, and can be applied to both valves.

1 is a schematic cross-sectional view showing an embodiment of a valve gear for an internal combustion engine according to the present invention. 1 is a schematic view of an internal combustion engine to which the present embodiment is applied. It is a longitudinal cross-sectional view of the hydraulic lash adjuster used for a present Example. It is the schematic explaining the effect | action of the hydraulic lash adjuster of a present Example. It is the schematic explaining the effect | action of the hydraulic lash adjuster of a present Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine 2 ... Cylinder block 4 ... Crankshaft 7 ... Cylinder head 8 ... Intake valve (engine valve)
DESCRIPTION OF SYMBOLS 8 ... Rocker arm 10 ... Intake side cam shaft 10a ... Drive cam 14 ... Rocker arm 18 ... Hydraulic lashia adjuster 21 ... Body 22 ... Seat member 23 ... Reservoir chamber 24 ... Plunger 25 ... High pressure chamber 26 ... Lift switching mechanism 29 ... Separator 32 ... Check Valve 33 ... Sliding hole 34 ... Piston 35/36 ... Spring (biasing means)
37 ... Guide long groove 38 ... Through hole (engagement part)
42 ... Hydraulic circuit 50 ... Electronic controller

Claims (4)

A camshaft that is rotationally driven by a crankshaft, a rocker arm that has one end abutting against the engine valve and transmitting the rotational force of the drive cam of the camshaft to the engine valve, and the other end of the rocker arm swingably supported And a hydraulic lash adjuster that zero-adjusts the gap between the engine valve and one end of the rocker arm,
A valve operating device for an internal combustion engine, wherein a lift switching mechanism for switching a valve lift amount of the engine valve according to an engine operating state is provided inside the hydraulic lash adjuster. A hydraulic lash adjuster for zero-adjusting a gap between one end of the rocker arm and the engine valve, while supporting the other end of the rocker arm with one end abutting the engine valve in a swingable manner,
A hydraulic lash adjuster characterized in that a lift switching mechanism for switching a valve lift amount of the engine valve in accordance with an engine operating state is provided inside a body of the hydraulic lash adjuster. The valve operating apparatus for an internal combustion engine according to claim 1,
The hydraulic lash adjuster is
A body held by the cylinder head;
A sheet member slidably provided inside the body;
A plunger which is slidably provided inside the seat member, and a tip portion which has advanced from one end opening of the body serves as a swing fulcrum of the rocker arm;
A high pressure chamber that is provided inside the other end of the body and that introduces hydraulic oil supplied to the interior of the seat member into the interior via a check valve;
A lift switching mechanism that is provided between the seat member and the plunger, and locks the plunger in the advanced position according to the engine operating state, or releases the lock;
A valve operating apparatus for an internal combustion engine, comprising: The valve operating apparatus for an internal combustion engine according to claim 3,
The lift switching mechanism is
A sliding hole formed in the plunger from a direction perpendicular to the axis;
A piston slidably provided inside the sliding hole;
Biasing means for holding the piston in the sliding position in the sliding direction in the sliding hole;
An engaging portion formed on a peripheral wall of the seat member and engageable with a tip portion of the piston;
A biasing member provided in the seat member for biasing the plunger in the advance direction;
With
A hydraulic circuit for supplying and discharging hydraulic pressure to a pressure receiving chamber formed on the rear end side of the piston;
A valve operating apparatus for an internal combustion engine, comprising a controller for controlling the operation of a flow path switching valve of the hydraulic circuit in accordance with an engine operating state.

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