JP4731521B2 - Rash adjuster and retainer assembly method - Google Patents

Description

  The present invention relates to a hydraulic lash adjuster in a valve gear for an internal combustion engine and a method for assembling a retainer provided in the lash adjuster.

  The hydraulic lash adjuster includes a bottomed cylindrical body fixed to a cylinder head, and a plunger that is movable in the axial direction within the body and supports a rocker arm at the top (for example, Patent Document 1). See). The inside of the plunger is a low-pressure chamber, the inside of the body is a high-pressure chamber defined by the bottom wall of the plunger, and a communication hole that communicates the low-pressure chamber and the high-pressure chamber is opened on the bottom wall of the plunger. The low pressure chamber and the high pressure chamber are filled with hydraulic oil supplied from the oil supply passage of the cylinder head through the communication hole. Further, a check valve for opening and closing the communication hole is provided in the high pressure chamber, and this check valve is housed in a retainer provided in the high pressure chamber. The retainer is urged by a retainer spring and pressed against the bottom wall of the plunger.

Here, when a downward pressing force acts on the plunger from the rocker arm side, the check valve closes the communication hole to seal the high pressure chamber, and the hydraulic pressure in the high pressure chamber prevents the plunger from descending. Also, when the volume in the high pressure chamber increases due to the rise of the plunger, the check valve descends relative to the plunger to open the communication hole, and hydraulic oil flows from the low pressure chamber into the high pressure chamber and operates into the high pressure chamber. The state filled with oil is maintained.
Japanese Patent Application Laid-Open No. 2004-211585

  By the way, in the case of the lash adjuster as described above, a retaining ring is fitted to the upper end opening edge of the body so that the plunger does not come out of the body in a single product state such as during transportation. However, since the plunger is prevented from coming off by the rocker arm when in use, there is a circumstance that the retaining ring is unnecessary, and there is a demand for eliminating the retaining ring in order to avoid an increase in the number of parts.

  The present invention has been completed based on the above circumstances, and an object thereof is to prevent the plunger from coming off from the body without increasing the number of parts.

  As means for achieving the above object, the invention of claim 1 includes a cylindrical body and a plunger that supports a rocker arm at the top and is movable in the axial direction while slidingly contacting the inner peripheral surface of the body. A low pressure chamber in which hydraulic oil is stored in the plunger, and a high pressure chamber in which the hydraulic oil is stored in the body and is partitioned from the low pressure chamber by a bottom wall of the plunger. Provided in the bottom wall of the plunger is provided with a communication hole for communicating the low pressure chamber and the high pressure chamber, and the high pressure chamber is provided with a check valve for opening and closing the communication hole, The high pressure chamber is a lash adjuster having a cage shape for accommodating the check valve, and provided with a retainer that is integrally press-fitted into the bottom wall of the plunger. The retainer includes the body Where the retaining piece for restricting the exit from the body of the plunger by being hooked on the stepped portion formed on the inner peripheral surface is provided with the features.

  The invention of claim 2 is characterized in that, in the invention of claim 1, a plurality of the retaining pieces are arranged at equal intervals in the circumferential direction on the outer peripheral edge of the retainer.

  According to a third aspect of the present invention, there is provided a method of assembling the retainer provided in the lash adjuster according to the first or second aspect, wherein in the process of inserting the plunger into the body, the retaining wall is retained by the bottom wall of the plunger. By pressing the piece, the retaining piece is slidably brought into contact with the inner peripheral surface of the body while being elastically bent, and the plunger is inserted into the body at a normal depth so that the retaining piece is connected to the stepped portion. It is characterized in that it reaches the corresponding position and elastically returns in the expanding direction.

According to a fourth aspect of the present invention, there is provided a method for assembling the retainer provided in the lash adjuster according to the first or second aspect, wherein a portion of the retainer that can be the retaining piece is radially outside the retaining piece. A retaining element piece with a reduced protrusion amount is formed, and an opposing wall is formed at the end of the step portion on the inner peripheral surface of the body so as to face the bottom wall of the plunger. In the process of inserting the plunger into the body, the retainer is displaced together with the bottom wall of the plunger, and the plunger is inserted into the body at a normal depth, whereby the retaining element piece is inserted into the opposing wall. and sandwiched between the bottom wall of the plunger, the retaining segment by its clamping force deformed so as protrude to the back side to become radially outward of the step portion, to mold the retaining piece Having the features in place.

<Invention of Claim 1>
Since the retaining piece provided on the retainer can prevent the plunger from coming off from the body, a dedicated member such as a retaining ring can be eliminated and the number of parts can be reduced.

<Invention of Claim 2>
Since a plurality of retaining pieces are arranged at equal intervals in the circumferential direction, the plunger can be retained with a good balance, and the stability of the retaining operation can be ensured.

<Invention of Claim 3>
The retaining piece can be easily incorporated into the body using its elasticity.

<Invention of Claim 4>
It is possible to prevent the inner peripheral surface of the body from being damaged by the retaining piece during the insertion of the plunger.

<Embodiment 1>
A first embodiment of the present invention will be described with reference to FIGS. The lash adjuster 10 of this embodiment is a hydraulic lash adjuster that supports the rocker arm 80 so as to be swingable in the vertical direction (axial direction), and includes a metal body 20 and a plunger 40.

  As shown in FIG. 1, the body 20 has a bottomed cylindrical shape in which a cylindrical cylindrical portion 22 is raised from the peripheral edge of a circular bottom portion 21. As shown in FIG. 5, the body 20 is removably inserted in a depth direction (vertical direction) into a support hole 91 that is recessed in the upper surface of the cylinder head 90. An oil supply port 93 that intersects with an oil supply path 92 of the cylinder head 90 is formed in the inner peripheral surface of the support hole 91 so as to open. A valve stem 71 is inserted into the stem hole 94 of the cylinder head 90 so as to be movable in the axial direction, and a valve portion 72 provided at the tip of the valve stem 71 opens and closes an intake passage 70 in a cylinder (not shown).

  A constricted outer concave portion 23 is formed on the outer peripheral surface of the cylindrical portion 22 of the body 20 so as to face the oil supply port 93, and the inner peripheral surface of the cylindrical portion 22 of the body 20 is constricted corresponding to the outer concave portion 23. An inner concave portion 24 is formed. A body hole 25 is formed in the cylindrical portion 22 of the body 20 so as to open to the outer recess 23 and the inner recess 24.

  Further, a stepped portion 26 is formed in the lower end portion of the inner peripheral surface of the body 20 so as to accommodate a retaining piece 63 of a retainer 48 described later. As shown in FIG. 3, the upper end of the stepped portion 26 is a tapered regulating surface 27 that gradually decreases in diameter as it goes upward, and the lower end of the stepped portion 26 is the inner upper surface of the bottom 21 of the body 20. The base portion 28 is built up at the corner where the inner peripheral surface of the body 20 intersects, and the inner peripheral surface on the bottom 21 side is positioned inside the inner peripheral surface on the plunger 40 side by the base portion 28. The retaining piece 63 is movable in the vertical direction in the stepped portion 26, and the tip portion of the retaining piece 63 abuts on the regulating surface 27 of the stepped portion 26, so that the retainer 48 and thus the plunger 40 are prevented from moving further upward. It has become so.

  On the other hand, the plunger 40 has a bottomed cylindrical shape in which a cylindrical peripheral wall 42 is raised from the peripheral edge of the circular bottom wall 41, is fitted into the body 20, and its outer peripheral surface is slid onto the inner peripheral surface of the body 20. It can move in the axial direction (vertical direction) while being in contact. A hemispherical support portion 43 that supports one end portion of the rocker arm 80 is formed on the upper end portion (top portion) of the plunger 40, and a vertical hole 44 that can supply hydraulic oil to the rocker arm 80 is formed in a trumpet shape in the support portion 43. It is formed to penetrate through.

  The inside of the plunger 40 is a low pressure chamber 45 surrounded by the bottom wall 41 and the peripheral wall 42, and the lower end portion in the body 20 defines a high pressure chamber 46 between the bottom portion 21 and the bottom wall 41 of the plunger 40. Yes. A communication hole 47 that allows the low-pressure chamber 45 and the high-pressure chamber 46 to communicate with each other is formed in the center portion of the bottom wall 41 so as to penetrate vertically.

  A retainer 48 is incorporated in the high-pressure chamber 46, and the retainer 48 is pressed against the lower surface of the bottom wall 41 of the plunger 40 by the urging force of a retainer spring 49 that is in contact with the bottom 21 of the body 20. Further, a flange portion 51 is provided on the outer peripheral edge of the lower surface of the bottom wall 41 over the entire circumference, and an inner space surrounded by the flange portion 51 is an assembly space 52 of the retainer 48 opened downward. ing. The retainer 48 can be integrally moved with the plunger 40 by being press-fitted into the assembly space 52 of the bottom wall 41. A base portion 28 is disposed below the flange portion 51, and the flange portion 51 can come into contact with the base portion 28 when the plunger 40 is lowered to the lowest point.

  In the high-pressure chamber 46, a spherical check valve 53 that opens and closes the communication hole 47 while being accommodated so as to be capable of restricting displacement in the radial direction (axial orthogonal direction) with respect to the retainer 48 is provided. A valve spring 54 is interposed between the check valve 53 and the check valve 53. The check valve 53 is always biased upward (bottom wall 41 side) by a valve spring 54 so that the check valve 53 opens only when the hydraulic pressure in the low pressure chamber 45 rises above the hydraulic pressure in the high pressure chamber 46. It is configured.

  Further, a recess 55 is formed on the outer peripheral surface of the plunger 40 at a position facing the inner recess 24 of the body 20, and a plunger that communicates the low-pressure chamber 45 and the recess 55 with the peripheral wall 42 of the plunger 40. A hole 56 is formed above the body hole 25.

  Now, the structure of the retainer 48 will be described in detail. The retainer 48 is made of metal and has a cage shape or a cup shape as a whole as shown in FIG. 2, and has a circular shape in plan view that receives the check valve 53 from below. Receiving plate 61, a blade plate 62 that rises from the outer peripheral edge of the receiving plate 61 and covers the circumferential side of the check valve 53, and protrudes from the outer peripheral edge of the blade plate 62 to prevent the plunger 40 from coming off. The stopper plate 63 is provided, and the receiving plate 61, the blade plate 62, and the stopper piece 63 are sequentially and continuously arranged radially outward.

  A raised portion 64 is provided at the center of the receiving plate 61 by raising the bottom, and an annular groove 65 is recessed in the outer peripheral portion of the receiving plate 61 so as to surround the raised portion 64. The valve spring 54 is positioned in an idle restricted state by bringing its lower end into contact with the groove bottom surface of the annular groove 65.

  As shown in FIG. 4, the slat 62 has a reverse U-shaped cross-section that rises slightly outward and then hangs down in a folded shape, and its substantially upper half is an assembly space of the bottom wall 41. 52, and the retainer spring 49 is positioned in the play-restricted state by bringing the upper end of the retainer spring 49 into contact with the bag-shaped inner upper surface. Three blades 62 are arranged on the outer peripheral edge of the receiving plate 61 at equal intervals in the circumferential direction, and the radial slits 66 located between the adjacent blades 62 function as an oil flow path. Oil can be distributed.

  The retaining piece 63 has a form that is integrally connected to the lower end of the slat 62 and projects substantially horizontally outward in the radial direction, and has a substantially square shape with rounded corners. In addition, the retaining piece 63 is connected to the circumferential center of the outer peripheral edge of each blade 62 so as to correspond to each blade 62, and is equally spaced in the circumferential direction (an angular difference of 120 degrees). All three are arranged. The distal end portion of the retaining piece 63 in the natural state is in a positional relationship with the base portion 28 and the regulating surface 27 of the body 20 in a plan view.

Next, a procedure for assembling the lash adjuster 10 will be described.
First, the retainer 48 that accommodates the check valve 53 and the valve spring 54 is integrally assembled to the bottom surface of the plunger 40 (the assembly space 52 on the lower surface of the bottom wall 41) in a press-fitted state. Subsequently, when the plunger 40 is inserted into the body 20, the plunger 40 is pushed down from the upper end opening of the body 20 in the axial direction. Then, as shown in FIG. 3, the outer peripheral surface of the plunger 40 comes into sliding contact with the inner peripheral surface of the body 20, and the retainer 48 is pressed by the bottom wall 41 of the plunger 40, so that the retaining piece 63 is elastically moved in the diameter reducing direction. While being bent, it comes into sliding contact with the inner peripheral surface of the body 20, and the retainer spring 49 is pressed by the retainer 48 to be elastically contracted. Thereafter, when the plunger 40 reaches the proper assembly position, as shown in FIG. 4, the retaining piece 63 is elastically returned in the expanding direction and enters the stepped portion 26, and is locked in the removal direction with the regulating surface 27. Arranged as possible.

  In the above case, when the lash adjuster 10 is transported to the assembly site with the cylinder head 90, if a force in the pulling direction acts on the plunger 40 due to vibration or the like, the retaining piece 63 is elastic against the step portion 26. As a result, the upward movement of the plunger 40 is restricted, and the plunger 40 is prevented from coming off from the body 20. Note that the allowable movement range of the plunger 40 is defined by the length range (vertical height range) of the step portion 26.

Next, the operation of the lash adjuster 10 will be described.
After the lash adjuster 10 is installed in the support hole 91 of the cylinder head 90, a part of the hydraulic oil flowing through the oil supply passage 92 is introduced into the lash adjuster 10 through the oil supply port 93, the body hole 25, and the plunger hole 56 in this order. The hydraulic oil is stored in the low pressure chamber 45 and the high pressure chamber 46.

  When the cam 30 rotates together with the camshaft 31 to which engine power is transmitted and the rocker arm 80 is pressed from above by the cam nose 32, the plunger 40 is pressed by one end of the rocker arm 80 and moves downward with respect to the body 20. Then, the hydraulic oil stored in the high pressure chamber 46 is compressed, and the pressure in the high pressure chamber 46 increases. As the pressure in the high pressure chamber 46 rises, some hydraulic oil in the high pressure chamber 46 rises between the inner peripheral surface of the cylindrical portion 22 of the body 20 and the outer peripheral surface of the peripheral wall 42 of the plunger 40, It flows into the low pressure chamber 45 through the hole 56. The total length of the lash adjuster 10 is slightly shortened by the amount of hydraulic oil flowing out from the high pressure chamber 46. Further, the body 20 and the plunger 40 are integrated into a rigid body by the pressure increase in the high pressure chamber 46, and the lash adjuster 10 becomes a fulcrum for the operation of the rocker arm 80.

  When the cam nose 32 moves upward from the lowest point with the rotation of the cam 30, the pressing state against the rocker arm 80 is released, and the plunger 40 is pushed back upward by the pressure in the high pressure chamber 46 and the urging force of the retainer spring 49. It is. When the pressure in the high pressure chamber 46 decreases and becomes lower than the pressure in the low pressure chamber 45 as the plunger 40 moves upward, the check valve 53 opens against the urging force of the valve spring 54, and the low pressure The hydraulic oil introduced into the chamber 45 flows into the high-pressure chamber 46 through the communication hole 47, and the entire length of the lash adjuster 10 is extended. The extension operation of the lash adjuster 10 prevents a gap from being formed between the support portion 43 of the lash adjuster 10 and the rocker arm 80, and the valve clearance is adjusted to zero.

  As described above, according to the present embodiment, in the lash adjuster 10 in a single product state, the retaining member 63 provided on the retainer 48 can prevent the plunger 40 from coming off from the body 20, so that a dedicated member such as a retaining ring is provided. It becomes unnecessary and the number of parts can be reduced.

In addition, since the three retaining pieces 63 are arranged at equal intervals in the circumferential direction, the plunger 40 can be retained in a balanced manner, and the stability of the retaining operation can be ensured.
Furthermore, with the insertion operation of the plunger 40 into the body 20, the retaining piece 63 can be easily incorporated into the body 20 using its elasticity.

<Embodiment 2>
Next, Embodiment 2 of the present invention will be described with reference to FIG. In the second embodiment, the method of assembling the retainer 48 (prevention piece 63) is different from that of the first embodiment, but the form of the lash adjuster 10 is substantially the same as that of the first embodiment.

  That is, according to the second embodiment, before the plunger 40 is inserted into the body 20, a portion that can become the retaining piece 63 (hereinafter, the retaining element piece 63 </ b> A) hangs downwardly from the lower end of the blade plate 62. The shape of the retaining piece 63 is different from that of the retaining piece 63 bent substantially horizontally outward in the radial direction from the lower end of the blade plate 62, and has not yet been formed as the retaining piece 63. The distal end (outer end) of the retaining piece 63A is positioned inward of the distal end (outer end) of the retaining piece 63 in the radial direction, and the amount of protrusion outward in the radial direction is suppressed.

  When the plunger 40 is inserted into the body 20, in the insertion process, the protrusion amount of the retaining element piece 63A is suppressed, and the retaining element piece 63A and the inner peripheral surface of the body 20 are in a non-contact state. Kept in. After that, when the plunger 40 is inserted at a normal depth, the retaining piece 63A is sandwiched between the flange portion 51 of the plunger 40 and the base portion 28 (corresponding to the opposing wall of the present invention), and by the clamping force The retaining piece 63A is bent substantially perpendicularly outward in the radial direction so as to follow the outer edge of the flange portion 51, whereby the retaining piece 63 is formed. Note that the stepped portion 26 in the second embodiment is deeper than that in the first embodiment so as to accommodate the retaining piece 63 (the retaining element piece 63A) protruding outward in the radial direction, and the formation range of the regulation surface 27 is also longer. ing.

  According to the second embodiment, the retaining piece 63 (the retaining element piece 63A) is not in contact with the inner peripheral surface of the body 20 during the insertion process of the plunger 40, and therefore, the inner peripheral surface of the body 20 is the retaining piece 63 (the retaining element 63). It can be prevented from being damaged by the piece 63A).

<Embodiment 3>
FIG. 7 shows Embodiment 3 of the present invention. In the third embodiment, as in the second embodiment, before the plunger 40 is inserted into the body 20, a portion that can become the retaining piece 63 is configured as a retaining element piece 63 </ b> B, and the retaining piece 63 is associated with the regular assembly of the plunger 40. Is formed.

  The retaining element piece 63B of the third embodiment has a shape that extends radially outward from the lower end of the blade 62 and then bulges radially inward, and the extending end is arranged facing inward. Has been. The outer end of the retaining piece 63B is positioned so as to be radially inward from the outer end of the retaining piece 63, and the protruding amount to the radially outer side is suppressed.

  According to the third embodiment, as in the second embodiment, the retaining piece 63 (the retaining element piece 63B) is not in contact with the inner peripheral surface of the body 20 in the process of inserting the plunger 40, and the inner peripheral surface of the body 20 is the retaining piece. It is possible to prevent damage by the 63 (the retaining piece 63B). In this case, since the retaining element piece 63B is sandwiched between the flange portion 51 and the base portion 28, the retaining element piece 63B is folded in the vertical direction (axial direction) to obtain a two-layered retaining element 63. Strength is increased. Further, since the retaining piece 63B hits the surface of the pedestal 28 and induces its folding operation, the retaining piece 63 can be formed smoothly and the pedestal 28 can be prevented from being damaged.

<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention.
(1) The retaining piece is made of a shape memory alloy that memorizes the expanded state, and has a reduced diameter in the plunger insertion process so that it is not in contact with the inner peripheral surface of the body. The form which can prevent that a surface is damaged may be sufficient.
(2) The retaining piece only needs to be provided in the retainer so as to be able to engage with the stepped portion of the body in the retaining state, and the shape, arrangement, and number thereof can be arbitrarily set.
(3) The use of the lash adjuster in the present invention is not particularly limited, and can be applied to all internal combustion engines such as gasoline engines and diesel engines.

Whole longitudinal cross-sectional view of the lash adjuster in Embodiment 1 Retainer top view Main part enlarged longitudinal sectional view showing a state in the middle of assembling the plunger Main part enlarged vertical sectional view showing a state in which the plunger is normally assembled Longitudinal cross section of valve gear with lash adjuster The principal part expansion longitudinal cross-sectional view which shows the assembly | attachment operation | movement of the plunger in Embodiment 2. FIG. The principal part expansion longitudinal cross-sectional view which shows the assembly | attachment operation | movement of the plunger in Embodiment 3. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Rush adjuster 20 ... Body 26 ... Step part 27 ... Restriction surface 40 ... Plunger 41 ... Bottom wall 45 ... Low pressure chamber 46 ... High pressure chamber 48 ... Retainer 53 ... Check valve 63 ... Stop piece

Claims (4)

A cylindrical body, and a plunger that supports the rocker arm at the top and is movable in the axial direction while sliding on the inner peripheral surface of the body,
In the plunger, a low pressure chamber in which hydraulic oil is stored is provided,
In the body, a high pressure chamber in which the hydraulic oil that is partitioned from the low pressure chamber by the bottom wall of the plunger is stored is provided,
The bottom wall of the plunger is provided with a communication hole that communicates the low pressure chamber and the high pressure chamber,
A check valve for opening and closing the communication hole is provided in the high-pressure chamber, and
The high pressure chamber is a lash adjuster having a cage shape for accommodating the check valve and provided with a retainer that is integrally press-fitted into the bottom wall of the plunger,
The lash adjuster is characterized in that the retainer is provided with a retaining piece for restricting the plunger from coming out of the body by being hooked by a stepped portion formed on the inner peripheral surface of the body.   The lash adjuster according to claim 1, wherein a plurality of the retaining pieces are arranged on the outer peripheral edge of the retainer at equal intervals in the circumferential direction. A method for assembling a retainer provided in the lash adjuster according to claim 1 or 2,
In the process of inserting the plunger into the body, by pressing the retainer with the bottom wall of the plunger, the retaining piece is slidably contacted with the inner peripheral surface of the body while being elastically bent,
A retainer assembling method, wherein the plunger is inserted into the body at a normal depth so that the retaining piece reaches a position corresponding to the stepped portion and elastically returns in the expanding direction. A method for assembling a retainer provided in the lash adjuster according to claim 1 or 2,
In the portion that can be the retaining piece in the retainer, a retaining element piece in a form that suppresses a protruding amount outward in the radial direction from the retaining piece is formed,
At the end of the stepped portion on the inner peripheral surface of the body, a facing wall is formed facing the bottom wall of the plunger,
In the process of inserting the plunger into the body, the retainer is displaced together with the bottom wall of the plunger ,
By inserting the plunger into the body at a normal depth, the retaining element piece is sandwiched between the opposing wall and the bottom wall of the plunger, and the retaining element piece is inserted into the back of the step portion by the clamping force. A retainer assembling method , wherein the retaining piece is formed by being deformed so as to protrude outward in the radial direction on the side .

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