JP2008025394A - Lash adjuster of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To exclude from a low pressure chamber 54 of a hydraulic lash adjuster 25 foreign matter that could be mixed in hydraulic fluid supplied into the low pressure chamber 54, thus preventing or controlling foreign matter from being caught in sliding friction parts in the low pressure chamber 54 to which the hydraulic fluid should be supplied, and reducing the rate of wear of the sliding friction parts. <P>SOLUTION: The protruding end of a plunger 52 which protrudes from a cylinder 51 is provided with an outlet port 52c for supplying the hydraulic fluid in the low pressure chamber 54 of the plunger 52 to the mating parts of the protruding end and a pivot recess part 24b. As the hydraulic fluid is introduced from the oil supply passage 12d of a cylinder head 12 into the low pressure chamber 54, the hydraulic fluid is swirled as it flows. Also, as any foreign matter mixed in the hydraulic fluid is centrifugally displaced, it is discharged out of a discharge opening 52d provided in a non-mating area with the pivot recess part 12d at the protruding end of the plunger 52. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a hydraulic lash adjuster used in a rocker arm type valve operating mechanism of an internal combustion engine.

  Generally, a rocker arm type valve operating mechanism in an internal combustion engine has an intake / exhaust camshaft centered offset from the central axis of the intake / exhaust valve, and the camshaft of the camshaft The arm is tilted and the valve is pressed by the rocker arm, and the lift amount of the valve can be set as large as possible.

  One end side in the longitudinal direction, which is the fulcrum of this rocker arm, is generally supported by a hydraulic lash adjuster (HLA) in order to keep the valve clearance at an appropriate value (for example, patents) References 1 and 2).

  This type of lash adjuster is installed in a state where it is embedded in the cylinder head, and mainly includes a cylinder, a plunger, and a check valve.

  A hollow plunger is accommodated in a cylindrical cylinder with a bottom so as to be slidable up and down. One end of the rocker arm in the longitudinal direction is projected to an end protruding from the upper opening of the cylinder, that is, a substantially hemispherical protruding end. A substantially hemispherical pivot recess formed on the side is fitted.

  The inner space of the plunger is a low pressure chamber, and the lower space formed between the bottom wall of the cylinder and the bottom wall of the plunger is a high pressure chamber. These low pressure chamber and high pressure chamber are Are communicated with each other by a passage (through hole) provided in the center of the bottom wall.

  The check valve is provided in the high pressure chamber side opening in the passage of the bottom wall portion of the plunger, and is opened and closed as necessary.

  The check valve includes a check ball, a ball retainer, a ball spring, and a plunger spring. The check ball is urged by a ball spring and a plunger spring so as to close the high pressure chamber side opening in the passage of the bottom wall portion of the plunger in a steady state.

  The low pressure chamber and the high pressure chamber are filled with hydraulic oil, which is generally used as lubricating oil in an oil pan of an internal combustion engine.

  Lubricating oil in the oil pan is sucked up by an oil pump and conveyed to an oil supply passage provided in the cylinder head. From this oil supply passage, a passage (through hole) formed through the cylinder in the radial direction inside and outside and a plunger It is introduced into the low-pressure chamber through a passage (through hole) formed through the peripheral wall portion in the radial direction. The hydraulic oil in the low pressure chamber is introduced into the high pressure chamber via a check valve as necessary.

  By the way, the protruding end of the plunger and the pivot recess of the rocker arm are both formed in a substantially hemispherical shape in order to prevent the rocker arm from separating after allowing the tilting operation when the rocker arm is tilted. is there.

That is, the fitting portion between the protruding end of the plunger and the pivot recess of the rocker arm is adapted to slide and friction with the tilting motion of the rocker arm, so that the low pressure chamber of the lash adjuster is placed on the top of the protruding end of the plunger. A discharge port for supplying the hydraulic oil to the fitting portion is provided.
JP-A-5-156908 JP 2004-197671 A

  In the above conventional example, there are concerns about the following problems.

  In other words, because the hydraulic oil supplied to the lash adjuster is used as the lubricating oil in the oil pan of the internal combustion engine, foreign particles such as wear powder, sludge, and carbon suit inside the engine are mixed in the hydraulic oil. Sometimes.

  When the working oil mixed with such foreign matter is supplied to the fitting portion between the protruding end of the plunger and the pivot recess through the low pressure chamber, the foreign matter mixed in the working oil is converted into the fitting portion. There is a possibility that the friction part of the fitting part may bite, and the wear of the fitting part may be advanced. There is room for improvement here.

  By the way, depending on the type of the rocker arm, the pivot recess is supplied to the fitting portion between the protruding end of the plunger and the pivot recess toward the contact surface between the rocker arm and the cam lobe of the camshaft that pushes the rocker arm. Some have a discharge port for spraying fresh hydraulic oil.

  In the case of such a rocker arm, similarly to the above, the working oil mixed with foreign matter is mixed into the working oil by being supplied to the contact surface between the cam lobe of the cam shaft and the roller of the rocker arm. There is a possibility that foreign matter may bite into the contact surface, and wear of the contact surface may be developed.

  The present invention was devised in view of the above-described circumstances. In the hydraulic lash adjuster provided in the valve mechanism of the internal combustion engine, foreign matter is temporarily mixed in the hydraulic oil supplied to the low pressure chamber. However, this foreign matter can be removed from the low-pressure chamber, and a sliding friction portion (for example, a fitting portion between the protruding end of the plunger and the pivot recess of the rocker arm, An object of the present invention is to prevent or suppress the entry of foreign matter into the contact surface with the pressing member, etc., and to reduce the wear progress of the sliding friction part.

  The present invention is a hydraulic lash adjuster used in a rocker arm type valve operating mechanism of an internal combustion engine, and a pivot recess of a rocker arm is fitted to the protruding end of the plunger from the cylinder. In use, a discharge port for supplying hydraulic oil in the low-pressure chamber inside the plunger to the fitting portion between the protruding end and the pivot recess is provided, and the oil supply path provided in the cylinder head By introducing the hydraulic oil into the low-pressure chamber, the hydraulic oil is swirled and the foreign matter mixed in the hydraulic oil is centrifugally displaced, and the plunger is not engaged with the pivot recess at the protruding end. It is characterized by being configured to be discharged to the outside from a discharge port provided in the area.

  According to this configuration, for example, lubricating oil stored in an oil pan of the internal combustion engine is supplied as hydraulic oil into the low pressure chamber of the plunger through an appropriate oil supply path installed in the internal combustion engine. Even if foreign matter (abrasion powder, sludge, carbon suit, etc. of an internal combustion engine) is mixed in, the foreign matter is discharged from the outlet of the plunger as the hydraulic oil swirls.

  The principle of foreign matter discharge will be described. First, when hydraulic oil is supplied into the low pressure chamber of the plunger, the hydraulic oil swirls and flows along the inner surface of the peripheral wall portion of the plunger in the low pressure chamber. Due to the centrifugal force generated by the swirling flow of the hydraulic oil, the foreign matter mixed in the hydraulic oil is displaced radially outward, and when this foreign matter reaches the position of the discharge port provided in the plunger, It will be discharged from the outside.

  The hydraulic fluid from which foreign matter has been removed in this way, or the hydraulic fluid in which foreign matter remains slightly, is supplied from the low pressure chamber of the plunger to the fitting portion between the protruding end of the plunger and the pivot recess of the rocker arm. Therefore, as in the conventional example, foreign matter mixed in the hydraulic oil is prevented or suppressed from entering the fitting portion. Therefore, it is advantageous in reducing the wear of the fitting portion between the protruding end of the plunger and the pivot recess of the rocker arm, and can contribute to improving the durability thereof.

  By the way, depending on the type of the rocker arm to be used, the pivot recess is provided with the hydraulic oil supplied to the fitting portion between the protruding end of the plunger and the pivot recess of the rocker arm, and a pushing member for pushing it. In such a case, there is a discharge port for feeding toward the contact surface. It becomes possible to suppress.

  In addition to the cam lobe of the intake / exhaust camshaft of the internal combustion engine, the pushing member described above is an operation characteristic such as the lift amount and working angle of the intake / exhaust valve according to the operating state of the internal combustion engine. This corresponds to an output arm (see FIG. 12 attached to the embodiment) of a variable valve mechanism for changing and adjusting the angle.

  Preferably, the cylinder and the peripheral wall of the plunger are each provided with a passage communicating with an oil supply passage provided in the cylinder head and the low-pressure chamber, and the passage of the plunger extends from the oil supply passage to the passage of the cylinder. It can be set as the structure inclined with respect to the straight line which connects the center of a plunger and the center of the channel | path of a cylinder so that the hydraulic fluid supplied through this may be introduced toward the surrounding wall part inner surface side of a plunger in a low pressure chamber.

  In this way, it is possible to specify an example of a configuration that generates the swirling flow of the hydraulic oil in the low pressure chamber. That is, by inclining the passage of the plunger, when hydraulic oil is introduced into the low pressure chamber from this passage, the hydraulic oil swirls along the inner surface of the peripheral wall portion of the plunger. Accordingly, when foreign matter is mixed in the hydraulic oil, the foreign matter is centrifugally displaced.

  According to this configuration, only the direction in which the hydraulic oil is introduced is devised, and no special configuration is added, which is advantageous in avoiding an excessive increase in manufacturing cost.

  The present invention also relates to a hydraulic lash adjuster used in a rocker arm type valve operating mechanism of an internal combustion engine, wherein a pivot recess of a rocker arm is fitted to the protruding end of the plunger from the cylinder. In the combined use state, a discharge port for supplying hydraulic oil in the low-pressure chamber inside the plunger to the fitting portion between the protruding end and the pivot recess is provided, and the peripheral wall portion of the cylinder and the plunger is provided. Each of the cylinder heads is provided with a passage communicating with the oil supply passage and the low-pressure chamber, and a plurality of passages of the plunger are provided at a plurality of circumferential positions of a peripheral wall portion of the plunger. Is arranged so that the working oil supplied from the oil supply passage is introduced toward the partition between the adjacent passages of the plunger. It is characterized in that it is inclined with respect to a straight line connecting the center of the mouth and the center of the plunger.

  In short, in this configuration, the cylinder passage is inclined so that the hydraulic oil collides with the partition between the passages of the plunger from the passage. Therefore, the plunger itself is brought into the cylinder by the pressure of the hydraulic oil. It will be gradually turned in one direction.

  As the plunger rotates in one direction, the sliding friction position between the pivot recess and the protruding end of the plunger accompanying the tilting motion of the rocker arm is shifted from moment to moment at the fitting portion of the protruding end of the plunger with respect to the pivot recess of the rocker arm. As a result, the fitting portion is less likely to be unevenly worn.

  According to the present invention, even if foreign matter is mixed in the hydraulic oil supplied to the low pressure chamber of the plunger, it is possible to remove the foreign matter from the low pressure chamber. Therefore, to the sliding friction part (for example, the fitting part of the protruding end of the plunger and the pivot concave part of the rocker arm, the contact surface of the rocker arm and its pushing member, etc.) to be supplied with hydraulic oil in the low pressure chamber It is possible to prevent or suppress the biting of foreign matter, which is advantageous in reducing the progress of wear of the sliding friction portion.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. First, FIG. 1 to FIG. 17 show an embodiment of the present invention.

  First, prior to the description of the portion to which the features of the present invention are applied, the configuration of a variable valve mechanism for an internal combustion engine which is a premise of the present invention will be described.

  Here, as shown in FIGS. 1 and 2, an in-line four-cylinder DOHC engine is used as the internal combustion engine 1, and a four-valve type with two intake valves 14 and two exhaust valves 15 per cylinder is taken as an example. In this example, the variable valve mechanism 3 is attached only to the two intake valves 14 and 14 per cylinder in the internal combustion engine 1.

  For simplicity of explanation, the variable valve mechanism 3 is not provided on the exhaust valve 15 side, but the variable valve mechanism 3 is provided on the exhaust valve 15 side in the same manner as the intake valve 14 side. Is also possible.

  In the first place, in the internal combustion engine 1, the intake valve 14, the exhaust valve 15, the intake camshaft 16, the exhaust camshaft 18, the rocker arm 24, the lash adjuster 25, and the like are referred to as a valve operating mechanism. The variable valve mechanism 3 is a mechanism that can continuously change the lift amount and operating angle of the intake valves 14 and 14 of this valve mechanism.

  The configuration of the variable valve mechanism 3 is described in detail in, for example, Japanese Patent Application Laid-Open No. 2001-263015. For example, as shown in FIGS. 1 to 11, a rocker shaft 31, a control shaft 32, and an actuator 33 are provided. And a valve lift mechanism 4.

  The rocker shaft 31 is supported by a large number of partition walls 21 provided at regular intervals on the cylinder head 12 so as to be immovable in the axial direction and the circumferential direction. The rocker shaft 31 is arranged in parallel with the intake camshaft 16 and the exhaust camshaft 18, that is, along the arrangement direction of the cylinders (combustion chambers 13).

  The control shaft 32 is inserted into the center hole of the rocker shaft 31 made of a hollow pipe so as to be axially displaceable.

  The actuator 33 drives the control shaft 32 in the axial direction, and is an appropriate drive source such as an electric motor or a hydraulic cylinder.

  The number of valve lift mechanisms 4 is the same as the number of cylinders, and is externally mounted on the rocker shaft 31 so as to correspond to each cylinder. The valve lift mechanism 4 is disposed between the cam lobe 17 of the intake camshaft 16 and the rocker arm 24, and includes an input arm 41, two output arms 42A and 42B, and a slider gear 43.

  Note that one end in the longitudinal direction of the rocker arm 24 is supported by the lash adjuster 25, and the other end in the longitudinal direction of the rocker arm 24 is in contact with the tappet 14 a at the upper end of the intake valve 14.

  The input arm 41 has a cylindrical housing 41 a, and a helical spline 41 b that meshes with the input-side helical spline 43 a of the slider gear 43 is formed on the inner peripheral surface thereof.

  In the input arm 41, a pair of forks 41cL and 41cR projecting radially outward is provided on the outer periphery of the housing 41a. A support shaft parallel to the rocker shaft 31 is provided between the pair of forks 41cL and 41cR. A roller 41e is rotatably mounted on the support shaft 41d.

  The output arms 42A and 42B both have a cylindrical housing 42a, and a helical spline 42b that meshes with the output-side helical spline 43b of the slider gear 43 is formed on the inner peripheral surface thereof. A nose 42c protruding outward in the radial direction is provided on the outer periphery of the housing 42a of the output arms 42A and 42B. The nose 42c is formed in a substantially triangular shape in a side view, and a cam surface 42d is provided on one side thereof.

  The slider gear 43 is externally mounted on the rocker shaft 31 so as to be movable in the axial direction in conjunction with the control shaft 32, and an input arm 41 and two output arms 42A and 42B are externally mounted on the outer diameter side thereof. .

  The slider gear 43 is formed in a cylindrical shape having a through-hole 43c in the center, and an input side helical spline 43a that meshes with the helical spline 41b of the input arm 41 is formed in the middle in the axial direction on the outer periphery. Output side helical splines 43b that mesh with the helical splines 42b of the output arms 42A and 42B are formed on both sides in the axial direction.

  The output side helical spline 43b has a smaller outer diameter than the input side helical spline 43a. The input-side helical spline 43a and the output-side helical spline 43b are formed so that the inclination directions of the teeth are opposite.

  Then, the input arm 41 is swung by the rotation of the cam lobe 17, and the intake valves 14, 14 are lifted via the rocker arm 24 by the output arms 42 A, 42 B swinging integrally with the input arm 41. It has become.

  The roller 41e of the input arm 41 is urged so as to be pressed against the cam lobe 17 of the intake camshaft 16 by the urging member 26. Further, the roller 24a of the rocker arm 24 is pressed against either the base circular portion of the housing 42a of the output arms 42A and 42B or the cam surface 42d of the nose 42c by the valve spring 14b of the intake valve 14.

  Here, the coupling form of the slider gear 43 to the rocker shaft 31 and the control shaft 32 will be described with reference to FIGS.

  In order to connect the slider gear 43 fitted to the rocker shaft 31 to the control shaft 32 in the rocker shaft 31 so as to be able to transmit power, the slider gear 43 has an inner circumferential groove 43d with a partial arc shape in a longitudinal section. A bushing 46 is provided.

  The bush 46 is formed with a pin insertion hole (through hole) 46 a in the middle in the circumferential direction, and is connected to the control shaft 32 via a connect pin 44.

  Specifically, the distal end portion of the connect pin 44 is inserted into the pin insertion hole 46 a of the bush 46, and the distal end portion of the connect pin 44 is inserted into the pin insertion hole 32 a of the control shaft 32. An intermediate portion of the connect pin 44 is inserted into the long hole 31 a of the rocker shaft 31.

  The slider gear 43 assembled in this way operates as follows.

  The control shaft 32 is movable in the axial direction with respect to the rocker shaft 31 within the range of the axial length of the long hole 31 a of the rocker shaft 31. Further, the slider gear 43 is fixed in the axial position with respect to the control shaft 32 by the engagement between the inner circumferential groove 43 d and the bush 46.

  Therefore, when the control shaft 32 is moved in the axial direction by driving the actuator 33, the operation is transmitted to the slider gear 43 via the connect pin 44 and the bush 46. As a result, the slider gear 43 moves in the axial direction in conjunction with the control shaft 32.

  In addition, since the bush 46 is movable in the circumferential direction in the inner circumferential groove 43d of the slider gear 43, the slider gear 43 is rotatable with respect to the control shaft 32 within the range. Thus, when the control shaft 32 is moved in the axial direction, the slider gear 43 rotates with respect to the control shaft 32 while moving in the axial direction.

  When the torque of the intake camshaft 16 is transmitted to the input arm 41, the torque is transmitted from the input arm 41 to the output arms 42A and 42B via the slider gear 43. At this time, the slider gear 43 It swings around the rocker shaft 31.

  In such a valve lift mechanism 4, the slider gear 43 is moved in the axial direction together with the control shaft 32, and the relative position in the axial direction between the slider gear 43 and the input arm 41 and the output arms 42A and 42B is changed. Twisting forces in opposite directions are applied to the input arm 41 and the output arms 42A and 42B. As a result, the input arm 41 and the output arms 42A and 42B rotate relative to each other, and the relative phase difference between the roller 41e of the input arm 41 and the nose 42c of the output arms 42A and 42B is changed.

  In the variable valve mechanism 3, the valve lift mechanism 4 for each cylinder is fixed to a common control shaft 32, so that all cylinders are moved along with the axial movement of the control shaft 32. The lift amount of the intake valve 14 is simultaneously changed. However, the valve lift mechanism 4 for each cylinder can be operated individually.

  Next, the operation of the variable valve mechanism 3 will be described.

  As shown in FIG. 9A, when the base circle portion of the cam lobe 17 is in contact with the roller 41e of the input arm 41, the roller 24a of the rocker arm 24 moves to the base circle portion of the housing 42a of the output arms 42A and 42B. Is in contact with. Therefore, the intake valve 14 is maintained in a state where the lift amount is “0” (a state where the intake port 12a is closed).

  When the roller 41e of the input arm 41 is pushed down through the lift portion of the cam lobe 17 with the clockwise rotation of the intake camshaft 16, the input arm 41 is counterclockwise with respect to the rocker shaft 31 as shown in FIG. It rotates in the turning direction (arrow A direction). As a result, the output arms 42A and 42B and the slider gear 43 rotate together.

  As a result, the cam surface 42d formed on the nose 42c of the output arms 42A and 42B comes into contact with the roller 24a of the rocker arm 24, and the roller 24a is pushed down by the pressing of the cam surface 42d.

  As shown in FIG. 9B, when the roller 24a of the rocker arm 24 is pressed by the cam surface 42d, the rocker arm 24 swings around the contact portion with the lash adjuster 25, and the intake valve 14 The valve is opened.

  When the control shaft 32 is moved to the maximum in the direction away from the actuator 33 (the direction of arrow F in FIG. 3), the roller 41e of the input arm 41 and the nose of the output arms 42A and 42B around the axis of the rocker shaft 31. The relative phase difference from 42c is maximized.

  Thereby, when the cam lobe 17 pushes down the roller 41e to the maximum, the displacement difference of the roller 24a of the rocker arm 24 becomes the largest, and the intake valve 14 is opened and closed with the maximum valve lift amount and operating angle.

  As shown in FIG. 10A, when the base circle portion of the cam lobe 17 is in contact with the roller 41e of the input arm 41, the contact position between the output arms 42A and 42B and the roller 24a is maximum from the cam surface 42d. It's far from the limit. When the roller 41e of the input arm 41 is pushed down by the lift portion of the cam lobe 17 by the rotation of the intake camshaft 16, the input arm 41 and the output arms 42A and 42B rotate together.

  However, in this case, since the contact position between the output arms 42A and 42B and the roller 24a is farthest from the cam surface 42d, the output until the push-down of the roller 24a of the rocker arm 24 by the cam surface 42d is started. The amount of rotation of the arms 42A and 42B is larger than that in the operating state shown in FIG. Further, when the roller 41e of the input arm 41 is pushed down through the lift portion of the cam lobe 17, the range of the cam surface 42d that comes into contact with the roller 24a is reduced to only a part of the base end side of the nose 42c. For this reason, the rocking | fluctuation amount of the rocker arm 24 according to depression of the roller 41e by the lift part of the cam lobe 17 becomes small.

  As shown in FIG. 10B, when the rocking amount of the rocker arm 24 is small, the intake valve 14 is opened with a smaller lift amount.

  Further, when the control shaft 32 is moved to the maximum in the direction approaching the actuator 33 (the arrow R direction in FIG. 3), the relative phase difference between the roller 41e and the nose 42c around the axis of the rocker shaft 31 is minimum. Become.

  As a result, the displacement amount of the roller 24a when the cam lobe 17 pushes the roller 41e to the maximum is minimized, and the intake valve 14 is opened and closed with the minimum lift amount and operating angle.

  10 shows a case where the maximum lift amount of the intake valve 14 is “0”. Therefore, even when the cam lobe 17 pushes down the roller 41e to the maximum, as shown in FIG. The lift amount of the intake valve 14 is maintained at “0”.

  The variable valve mechanism 3 according to this embodiment continuously changes the lift amount and the operating angle of the intake valve 14, and an example of the change waveform pattern is shown in FIG. As shown in FIG. 11, the greater the lift amount, the greater the operating angle. The operating angle of the intake valve 14 is an angle range (expressed by a crank angle in FIG. 11) from the valve opening timing IVO to the valve closing timing IVC of the intake valve 21.

  Next, portions to which the features of the present invention are applied will be described in detail with reference to FIGS. FIGS. 12 to 14 show the periphery of the intake valve 14 in FIG. 2 and FIGS. 15 to 17 show the periphery of the exhaust valve 15 in FIG. 2 in an enlarged manner.

  In short, with regard to the lash adjuster 25 arranged on the intake side and exhaust side, if foreign matter (for example, internal combustion engine wear powder, sludge, carbon suit, etc.) is mixed in the hydraulic oil supplied to it, the foreign matter is eliminated. Since it has been devised to have the function to do, will be described below.

  First, the basic configuration of the lash adjuster 25 will be described in detail.

  The lash adjuster 25 arranged on the intake side and the exhaust side is the same, but is called a hydraulic type, for example, and functions to keep the valve clearances of the intake valve 14 and the exhaust valve 15 always zero. is there.

  The lash adjuster 25 is installed in a state where it is embedded in the cylinder head 12, and mainly includes a cylinder 51, a plunger 52, and a check valve 53.

  The cylinder 51 is formed in a bottomed cylindrical shape, and the plunger 52 is formed in a hollow shape, and the plunger 52 is accommodated in the cylinder 51. By making the dimensions slightly smaller than the inner diameter of 51, the plunger 52 can slide up and down in the cylinder 51 without play in the radial direction.

  The internal space of the plunger 52 is a low pressure chamber 54, and the lower space formed between the bottom of the cylinder 51 and the bottom wall portion of the plunger 52 is a high pressure chamber 55, and the low pressure chamber 54 and the high pressure chamber 55 is in communication with a passage (through hole) 52 a provided in the center of the bottom wall of the plunger 52.

  The check valve 53 is provided in the high-pressure chamber side opening in the passage 52a in the bottom wall portion of the plunger 52, and is opened and closed as necessary.

  The check valve 53 includes a check ball 56, a ball retainer 57, a ball spring 58, and a plunger spring 59.

  The check ball 56 is urged by a ball spring 58 and a plunger spring 59 so as to close the high-pressure chamber side opening in the passage 52a in the bottom wall portion of the plunger 52 in a steady state.

  The low pressure chamber 54 and the high pressure chamber 55 are filled with hydraulic oil, which is generally used as lubricating oil in an oil pan (not shown) of the internal combustion engine.

  Lubricating oil in the oil pan is sucked up by an oil pump (not shown) and conveyed to an oil supply passage 12d provided in the cylinder head 12. From the oil supply passage 12d, a passage 51a provided in a peripheral wall portion of the cylinder 51 and a plunger 52 It is introduced into the low pressure chamber 54 through a passage 52b provided in the peripheral wall portion. The hydraulic oil in the low pressure chamber 54 is introduced into the high pressure chamber 55 via the check valve 53 as necessary. The passages 41a and 52b are holes that penetrate inward and outward in the radial direction.

  Here, the basic configuration of the rocker arm 24 to be supported by the lash adjuster 25 will also be described in detail.

  Here, the rocker arm 24 is a so-called end pivot type roller rocker arm. A roller 24a is rotatably supported in the middle in the longitudinal direction, and a plunger of the lash adjuster 25 is disposed at one end in the longitudinal direction. 52 is provided with a substantially hemispherical pivot recess 24b fitted to the protruding end of the valve 52, and the upper end tappets 14a, 15a of the intake valve 14 and the exhaust valve 15 are in contact with the other end in the longitudinal direction. In this configuration, the part 24c is provided.

  The top of the pivot recess 24b is slightly bulged outward, and a recess for oil storage is secured on the inner surface side.

  The fitting state between the protruding end of the plunger 52 of the lash adjuster 25 and the pivot recess 24b of the rocker arm 24 will be described in detail.

  A substantially hemispherical pivot recess 24b formed on one end in the longitudinal direction of the rocker arm 24 is fitted to an end of the plunger 52 protruding from the upper opening of the cylinder 51, that is, a substantially hemispherical projecting end. ing.

  As described above, the protruding end of the plunger 52 and the pivot recess 24b of the rocker arm 24 are both formed in a substantially hemispherical shape. When the rocker arm 24 tilts, the tilting operation is allowed and the two are separated from each other. This is to prevent this from happening.

  Such a fitting portion between the protruding end of the plunger 52 and the pivot recess 24b of the rocker arm 24 is adapted to slide and friction as the rocker arm 24 tilts as shown in FIGS. A discharge port 52c for supplying hydraulic oil in the low pressure chamber 54 of the lash adjuster 25 to the fitting portion is provided at the top of the protruding end of the plunger 52. The discharge port 52c is a hole that penetrates the thickness of the substantially hemispherical upper end of the lash adjuster 25.

  However, in general, the curvature of the protruding end of the plunger 52 is set to be smaller than the curvature of the pivot recessed portion 24b of the rocker arm 24, so that the protruding end of the plunger contacts the pivot recessed portion 24b on the surface. Instead, it is in the form of contact with a point or line. Therefore, with the tilting operation of the rocker arm 24, the fitting portion between the protruding end of the plunger 52 and the pivot recess 24b of the rocker arm 24 does not wear uniformly over the entire surface, but tends to wear locally. It has become a tendency.

  Next, the characteristic part of the lash adjuster 25 having the above-described configuration will be described.

  First, a foreign matter discharge port 52 d is provided in a non-fitting region of the protrusion 52 of the plunger 52 of the lash adjuster 25 with the pivot recess 24 b of the rocker arm 24.

  The discharge port 52d is a hole that is formed in the circumferential wall portion of the plunger 52 at an appropriate position in the circumferential direction near the projecting end so as to penetrate radially inward and outward.

  Specifically, the discharge port 52d is in the non-fitting region and in a region excluding the sliding region between the pivot recess 24b of the rocker arm 24 and the protruding end of the plunger 52 of the lash adjuster 25 due to the tilt of the rocker arm 24. is set up.

  With this arrangement, when the intake valve 14 or the exhaust valve 15 is in the closed state, it is exposed to the outside without being covered by the pivot recess 24b of the rocker arm 24, and the intake valve 14 and the exhaust valve 15 are opened. Even when the valve receiving portion 24c side of the rocker arm 24 is lowered, it is exposed to the outside without being covered by the pivot recess 24b.

  Further, the passage 52b of the plunger 52 is formed as an oblique hole so that when the hydraulic oil is introduced from the passage 52b into the low pressure chamber 54, the hydraulic oil swirls and flows in the low pressure chamber 54.

  Specifically, as shown in FIG. 13, the passage 52 b of the plunger 52 smoothly draws hydraulic oil flowing into the passage 51 a of the cylinder 51 from the oil supply passage 12 d of the cylinder head 12 into the low pressure chamber 54 and A predetermined angle θ is inclined with respect to a straight line L connecting the center P1 of the plunger 52 and the center P2 of the passage 51a of the cylinder 51 so as to face the inner surface of the peripheral wall.

  In other words, the passage 52b is inclined such that the inner opening is shifted to the downstream side in the hydraulic fluid flow direction in the oil supply passage 12d when the outer opening is used as a reference.

  As a result, as shown in FIG. 12, by introducing the working oil from the oil supply passage 12d provided in the cylinder head 12 into the low pressure chamber 54, the working oil is swirled and mixed with the working oil. While the foreign matter is centrifugally displaced, it is configured to be discharged to the outside from a discharge port 52d provided in a non-fitting region with the pivot recess 24b of the rocker arm 24 at the protruding end of the plunger 52.

  If the lash adjuster 25 having such characteristics is used, the lubricating oil stored in the oil pan (not shown) of the internal combustion engine 1 passes through the oil supply passage 12d, the passage 51a of the cylinder 51, and the passage 52b of the plunger 52. When hydraulic oil is supplied into the low pressure chamber 54 of the plunger 52, the hydraulic oil collides obliquely toward the inner surface of the peripheral wall portion of the plunger 52 in the low pressure chamber 54 along the inclination of the passage 52b of the plunger 52. Therefore, as shown by the arrows in FIGS. 12 and 13, the hydraulic oil swirls along the inner surface of the peripheral wall portion of the plunger 52.

  If foreign matter (abrasion powder, sludge, carbon suit, etc. of an internal combustion engine) is mixed in this hydraulic oil, the foreign matter is displaced radially outward by the centrifugal force generated by the swirling flow of the hydraulic oil. In other words, when the foreign matter reaches the position of the discharge port 52d provided in the plunger 52, it is discharged from here.

  In this way, the hydraulic oil from which foreign matter has been removed in the low pressure chamber 54 or the hydraulic oil in which the foreign matter remains slightly remains from the low pressure chamber 54 of the plunger 52 to the protruding end of the plunger 52 and the pivot recess 24 b of the rocker arm 24. Thus, the foreign matter is prevented or suppressed from being caught in the fitting portion as in the conventional example.

  Therefore, it is advantageous in reducing the progress of wear of the fitting portion between the protruding end of the plunger 52 and the pivot recess 24b of the rocker arm 24, and can contribute to improving the durability thereof.

  The present invention is not limited only to the above-described embodiments. For example, the following embodiments are also included in the technical scope of the present invention. It can be changed and implemented.

  (1) The internal combustion engine 1 in the above embodiment may be either a gasoline engine or a diesel engine, but a diesel engine contains a relatively large amount of carbon suit in the lubricating oil compared to a gasoline engine. Therefore, it can be said that it is particularly effective to apply the present invention to a valve operating mechanism of a diesel engine.

  (2) In the above embodiment, as a configuration for causing the hydraulic oil to swirl and flow in the low pressure chamber 54 of the plunger 52, the passage 52b of the plunger 52 is formed into an oblique hole so that the hydraulic oil is contained in the low pressure chamber 54 of the plunger 52. However, the present invention is not limited to this.

  For example, as shown in FIG. 18, the through hole 52b of the plunger 52 is arranged downstream from the straight line L connecting the center P1 of the plunger 52 and the center P2 of the passage 51a of the cylinder 51 in the oil supply direction (longitudinal direction) of the oil supply passage 12d. It can be installed by being offset by an appropriate amount X substantially in parallel.

  In this case, the hydraulic oil is introduced from the oil supply passage 12d through the passage 51a of the cylinder 51 and the passage 52b of the plunger 52 in a direction shifted from the center P in the low pressure chamber 54 of the plunger 52 to the outer diameter side. Therefore, the direction of the working oil is changed by the inner surface of the peripheral wall portion of the plunger 52, and the working oil turns and flows in the low pressure chamber 54.

  In this embodiment as well, the hydraulic oil turns and flows in the same manner as in the above embodiment. Therefore, even if foreign matter is mixed in the hydraulic oil, the foreign matter is radially outside by the centrifugal force generated by the swirling flow of the hydraulic oil. It will be displaced to the direction, and it will be discharged | emitted from the discharge port 52d of the plunger 52 outside. Therefore, similarly to the above embodiment, it is advantageous to reduce the progress of wear of the fitting portion between the protruding end of the plunger 52 of the lash adjuster 25 and the pivot recess 24b of the rocker arm 24.

  (3) As shown in FIG. 19, a circumferential groove 52e continuous in the circumferential direction is provided in a region where the passage 52b exists on the outer periphery of the peripheral wall portion of the plunger 52, and the passage 52b is opened at the groove bottom of the circumferential groove 52e. Can be configured.

  In this case, even if the passage 51a of the cylinder 51 and the passage 52b of the plunger 52 do not coincide with each other in the circumferential direction, the passage 51a and the passage 52b always communicate with each other through the circumferential groove 52e. This eliminates the need to align the passage 51a and the passage 52b when assembling the plunger 52 into the cylinder 51, so that the assembly work of the lash adjuster 25 can be performed easily and quickly. Can contribute.

  (4) For the rocker arm 24 shown in the above embodiment, as shown in FIGS. 20 and 21, the protruding end of the plunger 52 and the pivot recess 24 b of the rocker arm 24 are fitted near the top of the pivot recess 24 b. It is assumed that a discharge port 24d is provided for supplying the hydraulic oil supplied to the section toward a contact surface between the roller 24a of the rocker arm 24 and a pressing member (see below) that presses the roller 24a. Can do.

  The above-mentioned pushing member corresponds to the nose 42c of the output arm 42A (42B) on the intake side as shown in FIG. 20, and the exhaust camshaft 18 on the exhaust side as shown in FIG. It corresponds to cam lobe 19.

  In such a case, the progress of wear on the contact surface between the roller 24a of the rocker arm 24 and the pushing member can be suppressed by the foreign matter removing action of the lash adjuster 25 described in the above embodiment.

  (5) The lash adjuster 25 according to the present invention can be configured as shown in FIGS.

  22 and 23 show a lash adjuster 25 in a general valve operating mechanism in which the cam lobe 17 of the intake camshaft 16 is brought into direct contact with the roller 24a of the rocker arm 24. However, the lash adjuster 25 can also be used for the variable valve mechanism 3 as described in the above embodiment.

  The lash adjuster 25 is installed in a state where it is embedded in the cylinder head 12, and mainly includes a cylinder 51, a plunger 52, and a check valve 53.

  The cylinder 51 is formed in a bottomed cylindrical shape, and the plunger 52 is formed in a hollow shape, and the plunger 52 is accommodated in the cylinder 51. By making the dimensions slightly smaller than the inner diameter of 51, the plunger 52 can slide up and down in the cylinder 51 without play in the radial direction.

  The internal space of the plunger 52 is a low pressure chamber 54, and the lower space formed between the bottom of the cylinder 51 and the bottom wall portion of the plunger 52 is a high pressure chamber 55, and the low pressure chamber 54 and the high pressure chamber 55 is in communication with a passage (through hole) 52 a provided in the center of the bottom wall of the plunger 52.

  The check valve 53 is provided in the high-pressure chamber side opening in the passage 52a in the bottom wall portion of the plunger 52, and is opened and closed as necessary.

  The check valve 53 includes a check ball 56, a ball retainer 57, a ball spring 58, and a plunger spring 59.

  The check ball 56 is urged by a ball spring 58 and a plunger spring 59 so as to close the high-pressure chamber side opening in the passage 52a in the bottom wall portion of the plunger 52 in a steady state.

  The low pressure chamber 54 and the high pressure chamber 55 are filled with hydraulic oil, which is generally used as lubricating oil in an oil pan (not shown) of the internal combustion engine.

  Lubricating oil in the oil pan is sucked up by an oil pump (not shown) and conveyed to an oil supply passage 12d provided in the cylinder head 12. From the oil supply passage 12d, a passage 51a provided in a peripheral wall portion of the cylinder 51 and a plunger 52 It is introduced into the low pressure chamber 54 through a passage 52b provided in the peripheral wall portion. The hydraulic oil in the low pressure chamber 54 is introduced into the high pressure chamber 55 via the check valve 53 as necessary.

  A substantially hemispherical pivot recess 24b formed on one end in the longitudinal direction of the rocker arm 24 is fitted to an end of the plunger 52 protruding from the upper opening of the cylinder 51, that is, a substantially hemispherical projecting end. ing.

  In the lash adjuster 25 having such a configuration, the plunger 52 generally slides up and down, but hardly rotates. Therefore, the protruding end of the plunger 52 and the rocker arm 24 are arranged. It is considered that the fitting portion with the pivot concave portion 24b is worn along the tilting direction as the rocker arm 24 tilts.

  On the other hand, in the lash adjuster 25 described here, the sliding friction position of the protruding end of the plunger 52 with respect to the pivot recess 24b of the rocker arm 24 is shifted from moment to moment by gradually turning the plunger 52 in one direction. ing.

  In order to do this, the lash adjuster 25 shown in the figure forms the passage 51a of the cylinder 51 into an oblique hole inclined at a predetermined angle θ with respect to a straight line L connecting the center P2 of the inner opening and the center P1 of the plunger 52. Thus, a large number of passages 52b of the plunger 52 are provided at a plurality of locations in the circumferential direction of the peripheral wall portion of the plunger 52, and hydraulic oil introduced into the passage 51a from the oil supply passage 12d of the cylinder head 12 is supplied to the passage 52b adjacent to the plunger 52. It sprays toward the partition part 52f in between.

  In this case, the hydraulic oil introduced from the oil supply passage 12d of the cylinder head 12 into the passage 51a of the cylinder 51 collides with the partition wall portion 52f between the adjacent passages 52b of the plunger 52, and the plunger 52 is moved by the hydraulic oil pressure. The cylinder 51 is gradually rotated in one direction.

  As the plunger 52 rotates in one direction, the sliding friction between the pivot recess 24b and the projection end of the plunger 52 accompanying the tilting motion of the rocker arm 24 at the fitting portion of the projection end of the plunger 52 with respect to the pivot recess 24b of the rocker arm 24. Since the position is shifted from moment to moment, the fitting portion is less likely to be unevenly worn.

  As described above, in this example, the sliding friction position is shifted from time to time in view of the fact that local wear, that is, partial wear easily develops as the sliding friction position is fixed as in the conventional example. This suppresses the development of local wear, that is, uneven wear.

1 is a plan view schematically showing a cylinder head portion of an internal combustion engine in an embodiment to which a lash adjuster according to the present invention is applied. It is an arrow view of the (2)-(2) line cross section of FIG. It is a perspective view of the variable valve mechanism of FIG. It is a disassembled perspective view of the valve lift mechanism of FIG. It is a perspective view which decomposes | disassembles and shows the slider gear and rocker shaft of the valve lift mechanism of FIG. It is a perspective view which fractures | ruptures and shows the upper half of the valve lift mechanism of FIG. FIG. 5 is a cross-sectional view showing a connecting portion of a slider gear to the rocker shaft and control shaft of FIG. 4. FIG. 8 is a cross-sectional view taken along line (8)-(8) in FIG. 7. FIG. 3 is a side view used for explaining the operation when the relative phase difference between the input arm and the output arm in FIG. 2 is maximized. FIG. 3 is a side view used for explaining the operation when the relative phase difference between the input arm and the output arm in FIG. 2 is minimized. It is a figure which shows the change waveform pattern of the lift amount and working angle of an intake valve by the variable valve mechanism of FIGS. FIG. 3 is an enlarged view showing the vicinity of an intake valve in FIG. 2. It is an arrow view of the (13)-(13) line cross section of FIG. It is a figure which shows the state which pushed down the intake valve to the maximum in FIG. It is a figure which expands and shows the exhaust valve periphery of FIG. FIG. 16 is a cross sectional view taken along line (16)-(16) in FIG. 15. It is a figure which shows the state which pushed down the exhaust valve to the maximum in FIG. FIG. 14 is a view corresponding to FIG. 13, showing another embodiment of the structure for swirling the working oil in the lash adjuster according to the present invention. It is a figure corresponding to FIG. 13 in the modification of the plunger of the lash adjuster which concerns on this invention. It is a figure which shows the modification of the rocker arm by the side of intake shown in FIG. FIG. 16 is a view showing a modification of the exhaust-side rocker arm shown in FIG. 15. FIG. 13 shows a valve mechanism of an internal combustion engine to which a lash adjuster according to the present invention is applied, and corresponds to FIG. 12. FIG. 23 is a cross sectional view taken along line (23)-(23) in FIG. 22.

Explanation of symbols

1 Internal combustion engine
12 Cylinder head
14 Intake valve
15 Exhaust valve
16 Intake camshaft
17 Cam lob of intake camshaft
3 Variable valve mechanism
4 Valve lift mechanism
41 Input arm
42A first output arm
42B second output arm
43 Slider gear
24 Rocker arm
24a Roller arm roller
24b Pivot recess of rocker arm
24d Pivot recess outlet
25 Rush Adjuster
51 Cylinder of lash adjuster 25
51a Cylinder 51 passage
52 Plunger of Rush Adjuster 25
52b Plunger 52 passage
52c Discharge port of plunger 52
52d Discharge port of plunger 52
12d Cylinder head oil supply passage

Claims (3)

A hydraulic lash adjuster used for a rocker arm type valve operating mechanism of an internal combustion engine,
In the use state in which the pivot recess of the rocker arm is fitted to the projecting end of the plunger in the projecting end of the plunger, the hydraulic oil in the low-pressure chamber inside the plunger is fitted to the fitting portion of the projecting end and the pivot recess. A discharge port is provided for supplying to the
In addition, by introducing the hydraulic oil from the oil supply passage provided in the cylinder head into the low-pressure chamber, the hydraulic oil is swirled and the foreign matter mixed in the hydraulic oil is centrifugally displaced, A lash adjuster for an internal combustion engine, wherein the lash adjuster is discharged to the outside from a discharge port provided in a non-fitting region with the pivot recess at a protruding end. The lash adjuster for an internal combustion engine according to claim 1,
In the peripheral wall portions of the cylinder and the plunger, there are provided passages that connect the oil supply passage provided in the cylinder head and the low-pressure chamber,
The plunger passage is a straight line connecting the center of the plunger and the center of the cylinder passage so that hydraulic oil supplied from the oil supply passage through the cylinder passage is introduced toward the inner surface of the peripheral wall of the plunger in the low pressure chamber. A lash adjuster for an internal combustion engine, wherein the lash adjuster is inclined with respect to the internal combustion engine. A hydraulic lash adjuster used for a rocker arm type valve operating mechanism of an internal combustion engine,
In the use state in which the pivot recess of the rocker arm is fitted to the projecting end of the plunger in the projecting end of the plunger, the hydraulic oil in the low-pressure chamber inside the plunger is fitted to the fitting portion of the projecting end and the pivot recess. A discharge port is provided for supplying to the
In the peripheral wall portions of the cylinder and the plunger, there are provided passages that connect the oil supply passage provided in the cylinder head and the low-pressure chamber,
And the passage of the plunger is provided in many places around the circumference of the peripheral wall of the plunger, and the passage of the cylinder directs the hydraulic oil supplied from the oil supply passage to the partition between the adjacent passages of the plunger. A lash adjuster for an internal combustion engine, which is inclined with respect to a straight line connecting the center of the inner opening and the center of the plunger.

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