JP2008064020A - Hydraulic lash adjuster - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To introduce smoothly oil from a reservoir chamber to a high-pressure chamber, and certain separation of air from the oil compatible, in a hydraulic lash adjuster. <P>SOLUTION: The reservoir chamber 40 is divided in a plunger 32 slidably fitted with a bottomed-cylindrical body portion 31 of the hydraulic lash adjuster 19. When the oil is supplied from the reservoir chamber 40 to the high-pressure chamber 39 divided at a bottom portion of the body portion 31 through a check valve 35, a separator 41 stored in the reservoir chamber 40 is equipped with a plurality of bulkheads 43-47 having different shapes disposed in multi-stage in an axis L direction of the plunger 32. Therefore, the smooth introduction of the oil from the reservoir chamber 40 to the high-pressure chamber 39, and the certain separation of air from the oil can be compatible. The plurality of the bulkheads 43-47 is integrated by a coupling member 42, so that a number of parts or assembling man-hour can be reduced. The plurality of the bulkheads 43-47 is expanded upward in a V-shape, so that the air separated from the oil can be smoothly released upward. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention is formed in a bottomed cylindrical main body, a plunger that is slidably fitted inside the main body, a high-pressure chamber defined in the bottom of the main body, and the plunger. Hydraulic lash adjuster comprising: a reservoir chamber to which oil is supplied; a check valve that allows only oil to pass from the reservoir chamber to the high pressure chamber; and a separator that is housed in the reservoir chamber and separates air from the oil. About.

  One end is in contact with the stem end of the engine valve, and the other end of the rocker arm is in contact with the valve cam. A hydraulic lash adjuster for preventing a gap from being generated between an arm and a valve cam is known from Patent Documents 1 and 2 listed below.

In this type of hydraulic lash adjuster, the plunger is slidably fitted to the main body, and the plunger is protruded from the main body by the hydraulic pressure supplied to the reservoir chamber partitioned inside the plunger, and the other end of the rocker arm is moved. In addition to energizing, oil is supplied from the reservoir chamber of the plunger to the high-pressure chamber partitioned at the bottom of the main body via a check valve, and when a strong reaction force acts on the plunger from the rocker arm, the check valve is closed and the plunger It is designed to prevent the retreat. It is inevitable that some air enters the oil supplied to the reservoir chamber of the plunger. If this air enters the high-pressure chamber, the air in the high-pressure chamber is compressed when a strong reaction force acts from the rocker arm. Since the plunger may move backward, those described in Patent Documents 1 and 2 include a separator that separates air from oil in the reservoir chamber of the plunger.
JP-A-6-173622 JP 2004-251192 A

  By the way, the separator described in Patent Document 1 includes only one conical member having an opening formed at the upper end. Therefore, if the area of the opening is reduced in order to reliably separate air, the separator chamber There was a problem that oil could not be supplied smoothly to the high pressure chamber, and it was impossible to achieve both reliable separation of air and smooth supply of oil.

  Further, since the separator described in Patent Document 2 is composed of a spiral plate extending along the axis of the plunger, it is difficult not only to form the spiral plate, but also from the reservoir chamber to the high pressure chamber. Since the oil flow path to the tank becomes longer, the oil may not be smoothly introduced into the high pressure chamber.

  The present invention has been made in view of the above circumstances, and aims to achieve both smooth introduction of oil from a reservoir chamber to a high pressure chamber and reliable separation of air from oil in a hydraulic lash adjuster. To do.

  To achieve the above object, according to the first aspect of the present invention, a bottomed cylindrical main body, a plunger slidably fitted into the main body, and a bottom of the main body A high-pressure chamber partitioned into a plunger, a reservoir chamber formed in the plunger and supplied with oil, a check valve that allows only oil to pass from the reservoir chamber to the high-pressure chamber, and the reservoir chamber And a separator for separating air from oil. The hydraulic lash adjuster, wherein the separator includes a plurality of partitions having different shapes arranged in multiple stages in the axial direction of the plunger. Is proposed.

  According to the second aspect of the present invention, in addition to the configuration of the first aspect, the outer periphery of the plurality of partition walls has a gap between the circular arc section along the inner wall of the reservoir chamber having a circular cross section and the inner wall. The circular arc part of two adjacent partition walls complements each other when viewed in the axial direction to form a circle having the same shape as the inner wall of the reservoir chamber. A formula lash adjuster is proposed.

  According to the invention described in claim 3, in addition to the configuration of claim 1 or claim 2, the plurality of partition walls expand upward in a V shape and are integrated by the connecting member. A hydraulic lash adjuster is proposed.

  According to a fourth aspect of the present invention, in addition to the configuration of the third aspect, the connecting member is a rod-shaped member extending along the axis, and is in contact with the bottom of the reservoir chamber at the lower end thereof. The hydraulic lash adjuster is characterized in that a stopper for positioning the connecting member in the axial direction is formed, and the projected area in the axial direction of the stopper is smaller than the projected area in the axial direction of each partition wall. Is done.

  According to the invention described in claim 5, in addition to the structure of any one of claims 1 to 4, an oil return for returning oil leaked from the high-pressure chamber to the plunger chamber is provided in the plunger. A hydraulic lash adjuster is proposed in which a hole is formed and a distance between the two partition walls adjacent to each other at a position facing the oil return hole is larger than a distance between the two partition walls adjacent to each other at another position. The

  According to the configuration of the first aspect, the reservoir chamber is defined inside the plunger that is slidably fitted to the bottomed cylindrical main body, and the check valve is provided from the reservoir chamber to the high-pressure chamber defined at the bottom of the main body. When supplying oil through, the separator housed in the reservoir chamber includes a plurality of partition walls having different shapes arranged in multiple stages in the axial direction of the plunger, so that smooth introduction of oil from the reservoir chamber to the high pressure chamber, Both reliable separation of air from oil can be achieved.

  According to the second aspect of the present invention, the outer periphery of the plurality of partition walls of the separator includes an arc portion along the inner wall of the reservoir chamber having a circular cross section and a notch portion in which a gap is formed between the inner walls. The arcs of the two bulkheads complement each other when viewed in the axial direction to form a circle with the same shape as the inner wall of the reservoir chamber, so that it is difficult for the air mixed in the oil to pass through the bulkhead when flowing toward the high pressure chamber Thus, the air separation effect is enhanced.

  According to the third aspect of the present invention, since the plurality of partition walls are integrated by the connecting member, the number of parts and the number of assembling steps can be reduced, and the plurality of partition walls are expanded upward in a V shape. Therefore, the air separated from the oil can be smoothly released upward.

  According to the fourth aspect of the present invention, the stopper is formed at the lower end of the rod-shaped connecting member extending along the axis of the plunger so as to contact the bottom of the reservoir chamber and position the connecting member. Since the projected area in the direction is smaller than the projected area in the axial direction of each partition wall, it is possible to minimize the oil flowing from the reservoir chamber through the check valve into the high pressure chamber from being disturbed by the stopper.

  According to the fifth aspect of the present invention, the plunger is formed with an oil return hole for returning the oil leaked from the high pressure chamber to the reservoir chamber. Since the distance is set larger than the distance between the two adjacent partition walls, the oil from the oil return hole can smoothly return to the reservoir chamber without being obstructed by the partition walls.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  1 to 6 show an embodiment of the present invention. FIG. 1 is a sectional view of a cylinder head of an internal combustion engine, FIG. 2 is an enlarged sectional view of a part 2 in FIG. 1, and FIG. 4 is a sectional view taken along line 4-4 of FIG. 2, and FIG. 5 is a sectional view taken along line 5-5 of FIG. FIG. 6 is a vertical perspective view of the hydraulic lash adjuster.

  As shown in FIG. 1, an intake valve hole 15 and an exhaust valve hole 16 in which an intake port 12 and an exhaust port 13 formed in a cylinder head 11 of an internal combustion engine open into a combustion chamber 14 are respectively an intake valve 17 and an exhaust valve 18. Open and close. The hydraulic lash adjusters 19 and 19 having the same structure are mounted in the recesses 11a and 11b formed in the cylinder head 11, respectively, and an intake rocker arm 20 and an exhaust gas that are pivotally supported at one ends by the hydraulic lash adjusters 19 and 19 respectively. The intake cam 25 provided on the intake camshaft 24 and the exhaust cam 27 provided on the exhaust camshaft 26 are in contact with the rollers 22 and 23 provided in the intermediate portion of the rocker arm 21. The stem end 17a of the intake valve 17 biased in the valve closing direction by the valve spring 28 contacts the other end of the intake rocker arm 20, and the stem of the exhaust valve 18 biased in the valve closing direction by the valve spring 29. The end 18 a contacts the other end of the exhaust rocker arm 21.

  Therefore, the intake rocker arm 20 pivotally supported at one end by the intake side hydraulic lash adjuster 19 swings while the intermediate roller 22 is pressed by the intake cam 25 of the intake camshaft 24 and abuts the other end. The intake valve 17 is driven to open and close. Similarly, an exhaust rocker arm 21 pivotally supported at one end by a hydraulic lash adjuster 19 on the exhaust side swings while the intermediate roller 23 is pressed by the exhaust cam 27 of the exhaust camshaft 26 and contacts the other end. The exhaust valve 18 in contact is driven to open and close.

  At that time, when a gap is generated between the roller 22 of the intake rocker arm 20 or the roller 23 of the exhaust rocker arm 21 and the intake cam 25 or the exhaust cam 27, or the other end of the intake rocker arm 20 or the exhaust rocker arm 21. When a gap is generated between the other end of the valve and the stem end 17a of the intake valve 17 or the stem end 18a of the exhaust valve 18, the hydraulic lash adjuster 19 is extended by hydraulic pressure to eliminate the gap. Further, when a reaction load is applied to the hydraulic lash adjuster 19 from the intake rocker arm 20 or the exhaust rocker arm 21, the hydraulic lash adjuster 19 is locked so as not to contract, thereby preventing the generation of the gap.

  As apparent from FIGS. 2 and 6, the hydraulic lash adjuster 19 has a bottomed cylindrical main body 31 whose bottom surface is closed and whose top surface is open, and a plunger 32 that is slidably fitted to the main body portion 31. And a fulcrum member 33 formed with a partial spherical contact surface 33a that contacts one end of the intake rocker arm 20 or the exhaust rocker arm 21 is screwed onto the upper end of the plunger 32. A return spring 34 is contracted between a lower surface of a flange 32 a projecting annularly on the upper portion of the plunger 32 and a step portion 31 a formed on the upper portion of the main body portion 31. 32 is urged in a direction protruding upward from the main body 31. A recess 32b is opened at the lower end of the plunger 32, and the ball-shaped valve element 36 of the check valve 35 is accommodated in the recess 32b. In order to prevent the valve body 36 from falling off, a cap 37 is press-fitted into the recess 32b. A valve seat 38 on which the valve body 36 can be seated is formed at the upper end of the recess 32b.

  A high-pressure chamber 39 is defined between the bottom of the main body 31 and the lower end of the plunger 32, and a reservoir chamber 40 penetrating in the axis L direction is defined inside the plunger 32. The check valve 35 is disposed between the communication hole 32c at the lower end of the reservoir chamber 40 and the high-pressure chamber 39. The check valve 35 is closed when a load for pushing the plunger 32 downward into the main body 31 is generated. The lowering of the plunger 32 is prevented, and when a load is generated in which the plunger 32 protrudes upward from the main body 31, the valve 32 is opened to allow the plunger 32 to rise.

  A separator 41 is accommodated in the reservoir chamber 40 in order to separate air from oil. The separator 41 includes a rod-shaped connecting member 42 disposed on the axis L, five partition walls 43 to 47 provided at predetermined intervals in the intermediate portion of the connecting member 42, and a stopper provided at the lower end of the connecting member 42. 48, and the number of parts can be reduced by integrally molding them with synthetic resin. In the separator 41 inserted from above into the reservoir chamber 40, the bifurcated stopper 48 comes into contact with the bottom of the reservoir chamber 40, and in this state, the fulcrum member 33 is screwed onto the upper end of the plunger 32. It is stored so that it cannot move up and down.

  As apparent from FIGS. 2 to 6, among the five partition walls 43 to 47 provided in the separator 41, the first, third and fifth first partition walls 43, 45 and 47 from the top are the same. The second and fourth second partition walls 44 and 46 from the top have the same shape different from that.

  As shown in FIG. 3, the first partition walls 43, 45, 47 are formed by connecting two first arc portions a, a along the inner wall 40 a of the circular cross section of the reservoir chamber 40 and the two first arc portions a, a. Two first cutouts b and b are provided, and the two first cutouts b and b have a gap between the circular inner wall 40a of the reservoir chamber 40. The first partition walls 43, 45, 47 are bent in a V shape at the portion connected to the connecting member 42 so that the two first arc portions a, a are higher.

  On the other hand, as shown in FIG. 4, the second partition walls 44 and 46 connect the two second arc portions c and c along the inner wall 40 a of the circular cross section of the reservoir chamber 40 and the two second arc portions c and c. Two second cutouts d and d are provided, and the two second cutouts d and d have a gap between the circular inner wall 40a of the reservoir chamber 40. The second partition walls 44 and 46 are bent in a V shape at a portion connected to the connecting member 42 so that the two second cutout portions d and d are raised.

  The V-shaped directions of the five partition walls 43 to 47 are aligned. That is, when viewed in the direction of FIG. 2, the five partition walls 43 to 47 are all V-shaped. The reason is that, when the separator 41 is injection-molded with a synthetic resin, molding with a two-part mold is possible. The first circular arc portions a, a of the first partition walls 43, 45, 47 and the second circular arc portions c, c of the second partition walls 44, 46 are arranged with a phase shift of 90 °. The portions a and a and the second arc portions c and c complement each other to form the same circular shape as the cross section of the inner wall 40a of the reservoir chamber 40. In other words, when viewed in the direction of the axis L of the plunger 32, the five partitions 43 to 47 are completely obstructed so that the other side cannot be seen.

  The projected area when the stopper 48 provided at the lowermost end of the connecting member 42 is viewed in the direction of the axis L (see FIG. 5) is the same as the first partition 43, 45, 47 or the second partition 44, 46 viewed in the direction of the axis L. It is smaller than the projected area (see FIGS. 3 and 4).

  Oil supply holes 32d and 32d pass through in a radial direction directly below the flange 32a of the plunger 32, and oil return holes 32e and 32e facing the inner surface of the main body 31 are provided below the oil supply holes 32d and 32d. It penetrates in the radial direction. The interval β between the second partition 44 and the first partition 45 located above and below the oil return holes 32e, 32e is larger than the interval α between the other partitions.

  Next, the operation of the embodiment of the present invention having the above configuration will be described.

  Pressurized oil is supplied to the reservoir chamber 40 through oil supply holes 32d and 32d formed in the plunger 32 of the hydraulic lash adjuster 19, and the check valve 35 is opened by the pressure to pressurize the high pressure chamber 39 as well. Oil is supplied. As a result, the plunger 32 is urged in a direction that protrudes upward from the main body 31, and in cooperation with the elastic force of the return spring 34 that similarly urges the plunger 32 in a direction that protrudes upward from the main body 31. The backlash generated in the intake rocker arm 20 or the exhaust rocker arm 21 is suppressed.

  That is, a gap is generated between the roller 22 of the intake rocker arm 20 or the roller 23 of the exhaust rocker arm 21 and the intake cam 25 or the exhaust cam 27, or the other end of the intake rocker arm 20 or the other end of the exhaust rocker arm 21. And a stem end 17a of the intake valve 17 or a stem end 18a of the exhaust valve 18, the plunger 32 protrudes from the main body 31 to eliminate the gap, and the intake valve 17 or the exhaust valve 18 Enables smooth operation.

  When the reaction load is applied to the hydraulic lash adjuster 19 from the intake rocker arm 20 or the exhaust rocker arm 21 and the plunger 32 is pushed into the main body 31, and the volume of the reservoir chamber 40 is reduced, the check valve 35 is closed. Since the high-pressure chamber 39 is sealed, the downward movement of the plunger 32 is suppressed and the generation of the gap is prevented.

  The oil leaked from the high pressure chamber 39 passes through the gap between the main body 31 and the plunger 32 and is returned from the oil return holes 32e and 32e to the reservoir chamber 40. However, the second partition wall 44 is a portion facing the oil return holes 32e and 32e. Since the interval β between the first partitions 45 is larger than the interval α between the other partitions, the return of oil to the reservoir chamber 40 is not hindered by the second partitions 44 and the first partitions 45. .

  Now, it is inevitable that some air is mixed into the oil supplied from the oil supply holes 32d and 32d to the reservoir chamber 40, but when the compressible air enters the high-pressure chamber 39, the check valve 35 is closed. Sometimes the plunger 32 cannot be prevented from descending, so that air is separated from the oil by the separator 41.

  When the oil supplied from the oil supply holes 32d and 32d flows downward in the reservoir chamber 40 toward the high-pressure chamber 39, the first partition walls 43, 45, and 47 of the separator 41 arranged in the reservoir chamber 40 and the second Since the phases of the partition walls 44 and 46 are alternately shifted by 90 ° to form a labyrinth, separation of air from the oil is promoted. Further, since the first partition walls 43, 45, 47 and the second partition walls 44, 46 of the separator 41 are formed in a V-shape that expands upward, the air separated from the oil is supplied to the first partition walls 43, 45, 47. And it is not trapped by the second partition walls 44 and 46 to form an air reservoir.

  The projected area in the axis L direction of the stopper 48 provided at the position facing the check valve 35 is smaller than the projected area in the axis L direction of the first partition walls 43, 45, 47 or the second partition walls 44, 46. Therefore, it is possible to minimize the oil 48 flowing from the reservoir chamber 40 to the high pressure chamber 39 from being blocked by the stopper 48.

  As described above, the separator 41 according to the present embodiment includes the plurality of partition walls 43 to 47 having different shapes arranged in multiple stages in the direction of the axis L of the plunger 32, so that the oil from the reservoir chamber 40 to the high pressure chamber 39 is supplied. Both smooth introduction and reliable separation of air from oil can be achieved.

  Further, in the separator made of the spiral plate described in Patent Document 2, the outer peripheral surface of the separator may block the oil return hole if positioning in the rotational direction is not performed at the time of assembly. In the separator 41 according to the embodiment, if the vertical positions of the partition walls 43 to 47 are set so as not to interfere with the oil return holes 32e and 32e, it is not necessary to position in the rotational direction at the time of assembly. Can be simplified and the number of assembly steps can be reduced.

  The embodiments of the present invention have been described above, but various design changes can be made without departing from the scope of the present invention.

  For example, the number and shape of the partition walls 43 to 47 of the separator 41 are not limited to the embodiment.

Cross section of cylinder head of internal combustion engine 2 is an enlarged sectional view of part 2 in FIG. 3-3 sectional view of FIG. Sectional view along line 4-4 in FIG. Sectional view along line 5-5 in FIG. Vertical perspective view of hydraulic lash adjuster

Explanation of symbols

31 Body 32 Plunger 32e Oil return hole 35 Check valve 39 High pressure chamber 40 Reservoir chamber 40a Inner wall 41 Separator 42 Connecting member 43-47 Partition 48 Stopper a, c Arc part b, d Notch L Axis line

Claims (5)

A bottomed cylindrical main body (31), a plunger (32) slidably fitted inside the main body (31), and a high-pressure chamber (39) defined at the bottom of the main body (31) ), A reservoir chamber (40) formed in the plunger (32) and supplied with oil, and a check valve that allows only oil to pass from the reservoir chamber (40) to the high-pressure chamber (39) (35) and a hydraulic lash adjuster comprising a separator (41) housed in the reservoir chamber (40) and separating air from oil,
The separator (41) includes a plurality of partition walls (43 to 47) having different shapes arranged in multiple stages in the axis (L) direction of the plunger (32).   On the outer periphery of the plurality of partition walls (43 to 47), a gap is formed between the arc portion (a, c) along the inner wall (40a) of the reservoir chamber (40) having a circular cross section and the inner wall (40a). And the arc portions (a, c) of the two adjacent partition walls (43-47) complement each other when viewed in the direction of the axis (L). The hydraulic lash adjuster according to claim 1, characterized in that it forms a circle of the same shape as the inner wall (40a) of (40).   The hydraulic pressure according to claim 1 or 2, wherein the plurality of partition walls (43 to 47) expand upward in a V shape and are integrated by a connecting member (42). Formula lash adjuster.   The connecting member (42) is a rod-shaped member extending along the axis (L), and the lower end of the connecting member (42) contacts the bottom of the reservoir chamber (40) to connect the connecting member (42) to the axis (L). A stopper (48) for positioning in the direction is formed, and the projected area in the axis (L) direction of the stopper (48) is smaller than the projected area in the axis (L) direction of each partition wall (43 to 47). The hydraulic lash adjuster according to claim 3, wherein: The plunger (32) is formed with an oil return hole (32e) for returning oil leaked from the high pressure chamber (39) to the reservoir chamber (40), and adjacent to the oil return hole (32e) at a position facing the oil return hole (32e). The distance between the two partition walls (43 to 47) is larger than the distance between the two partition walls (43 to 47) adjacent to each other at other positions. Hydraulic lash adjuster as described in 1.

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