JP2013170663A - Shock absorber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To generate damping force as setting, with respect to a hydraulic shock absorber incorporated into a suspension of a vehicle.SOLUTION: A shock absorber includes a partition wall body 3 for partitioning pressure chambers R1 and R2 and a leaf valve 4 laminated on the partition wall body 3, includes a boss part 12 for fixing an inner peripheral side end part of the leaf valve 4 and a seat part 13 for leaving-seating an outer peripheral side end part of the leaf valve 4, and has a height difference for heightening the seat part 13 more than the boss part 12 between the boss part 12 and the seat part 13. A space between the outside edge of the boss part 12 and the outside edge of the seat part 13 is made to exist on the same curved surface or the same circular arc surface of gradually heightening toward the outside from the inside of the partition wall body 3, and the boss part 12 is made to exist on the curved surface or the circular arc surface or is formed as a horizontal plane.

Description

  The present invention relates to a shock absorber, and more particularly to an improvement of a hydraulic shock absorber incorporated in a suspension of a vehicle.

  In the hydraulic shock absorber incorporated in the suspension of the vehicle, in order to improve the riding comfort of the vehicle, for example, it is required that the damping force generated in each part of the four wheels is embodied as set.

  Therefore, the damping valve provided in the hydraulic shock absorber has, for example, a piston that is a partition wall and a leaf valve that is stacked on the piston, and the piston has a port that communicates with a pressure chamber defined by the piston, The leaf valve is provided at one end of the piston so as to be free from the outer peripheral end by being fixed to the inner peripheral end, and closes the downstream end of the port so as to be openable.

  On the other hand, at one end of the piston, for example, as disclosed in Patent Document 1, an inner peripheral boss portion for fixing and fixing an inner peripheral end of the leaf valve, and an outer peripheral end of the leaf valve And a seat portion on the outer peripheral side for detachably seating.

  And, it is assumed that there is a height difference between the boss part and the sheet part, and this height difference is realized by making the sheet part higher than the boss part. Specifically, the boss part and the sheet facing the pressure chamber Are on the same conical surface.

  Therefore, in the leaf valve laminated on one end of the piston, there is a height difference between the boss part and the seat part, so that the inner peripheral side end part is fixed to the boss part and the outer peripheral side end part becomes the seat part. When in a seated state, an initial load is applied.

  Therefore, in the hydraulic shock absorber, when the working fluid from the high pressure side deflects the outer peripheral side end portion of the leaf valve and passes through the gap between the seat portion and flows out to the low pressure side, the leaf valve is initialized. Since a load is applied, there is a pressure loss that becomes larger as a whole as compared with a case where the initial load is not applied, and a high damping force can be generated.

JP 2004-176775 A

  However, in the above-described hydraulic shock absorber, the damping force generated by the leaf valve is not as set, and there is a concern that the magnitude of the damping force varies from product to product.

  In the hydraulic shock absorber described above, as shown in FIG. 3, the height difference H between the boss part P1 and the sheet part P2 is such that the boss part P1 and the sheet part P2 are on the same conical surface. It is embodied by doing.

  For this reason, when laminating the leaf valve V on one end of the piston P, the inner peripheral side end is pressed against the boss P1 by a force from the vertical direction. At that time, the boss P1 It is conceivable that the outer edge P3 of the elastic deformation occurs.

  Therefore, in the leaf valve V, as shown by a solid line in FIG. 3, an inner peripheral side end portion pressed against the boss portion P1 and a portion closer to the outside of the piston P than the outer edge P3 of the boss portion P1. A local deformation occurs in the connection portion V2 with V1.

  If the force that fixes the inner peripheral end to the boss part P1 varies, or if there is a dimensional error in the height or outer diameter of the boss part P1, the amount of deformation in the connecting part V2 is different. The initial load applied to the outer peripheral side end of the leaf valve V varies.

  As a result, in the hydraulic shock absorber, the generated damping force is not as set, and the magnitude of the damping force varies from product to product, resulting in different riding feelings in the vehicle. .

  The present invention has been developed in view of the above-described present situation, and an object thereof is to provide a shock absorber capable of generating a damping force as set.

  In order to achieve the above-described object, the configuration of the present invention includes a partition body that partitions the pressure chamber, and a leaf valve that is stacked on the partition body, and fixes the inner peripheral end of the leaf valve. A boss portion and a seat portion for separating and seating the outer peripheral side end portion of the leaf valve, and having a height difference that makes the seat portion higher than the boss portion between the boss portion and the seat portion. In the shock absorber, the space between the outer edge of the boss part and the outer edge of the sheet part is on the same curved surface or the same arc surface gradually increasing from the inner side to the outer side of the partition body, It is assumed that the boss portion is on the curved surface or the arc surface, or is a horizontal plane.

  Therefore, the boss portion is formed on a horizontal plane, or on the same curved surface or the same arc surface that gradually increases from the inner side to the outer side of the partition body. It can be in a state close to a horizontal plane.

  Since the space between the outer edge of the boss part and the outer edge of the sheet part is on the same curved surface or the same arc surface that gradually increases from the inner side to the outer side of the partition body, the boss part and the sheet part In the leaf valve spanned between the two, the local deformation at the connecting portion between the inner peripheral side end portion fixed to the boss portion and the outer peripheral edge of the boss portion is prevented.

  Therefore, even if the force for fixing the inner peripheral side end of the leaf valve to the boss portion varies, or there is a dimensional error in the height or outer diameter of the boss portion, the above connected portion In addition, local deformation does not occur, and even if deformation occurs, the amount of deformation does not increase, and the initial load applied to the leaf valve does not vary.

  As a result, in the shock absorber, the damping force is generated as set, and the magnitude of the damping force does not vary from product to product. For example, when the hydraulic shock absorber is incorporated in the suspension of the vehicle, the riding feeling It is possible to stabilize the vehicle and eliminate variations, and to improve the reproducibility of the ride feeling.

It is a fragmentary longitudinal cross-section which shows the piston part by one Embodiment of this invention. It is a longitudinal cross-sectional view which expands and shows the leaf valve seat part in FIG. It is a longitudinal cross-sectional view which expands and shows the leaf valve seat part made into a prior art example.

  Hereinafter, the present invention will be described based on the illustrated embodiment. A shock absorber according to the present invention is, for example, a hydraulic shock absorber incorporated in a suspension of a vehicle, and performs a predetermined damping action during expansion and contraction operation. Suppresses vibrations of the vehicle body and axle.

  The hydraulic shock absorber is formed in an annularly formed partition wall that is held by the distal end portion 2a of the rod 2 that is inserted and slidably inserted into the cylinder 1 so as to be able to enter and leave the cylinder 1 that stores the working fluid as the working fluid. The piston 3 is a body, and the piston 3 is formed by laminating a leaf valve 4 on the expansion side and a leaf valve 5 on the compression side. The working fluid may be made of a fluid other than the working oil.

  More specifically, the piston 3 is slidably inserted into the cylinder 1 and is inserted into the cylinder 1 as a lower pressure chamber R1 in FIG. 1 and in the other chamber as an upper pressure chamber in FIG. In addition to partitioning R2, it has an opening side port 3a on the inner peripheral side enabling communication between the one chamber R1 and the other chamber R2, and a pressure side port 3b on the outer peripheral side.

  Therefore, in the hydraulic shock absorber, when the piston 3 moves in the cylinder 1 and the one chamber R1 and the other chamber R2 are widened and narrowed, the hydraulic oil passes through the expansion side port 3a and the pressure side port 3b. And the other chamber R2.

  On the other hand, the piston 3 is formed in an annular shape on the inner peripheral side in order to stack the extended leaf valve 4 on one end which is the other chamber R2 side end, and an inner peripheral side end (not shown) of the leaf valve 4 is provided. There is a boss portion 12 that is fixedly seated, and a seat portion 13 that is annularly formed on the outer peripheral side and seats an outer peripheral side end portion (not shown) of the leaf valve 4 so as to be detachably seated. An annular groove 11 serving as a recess is defined between the boss portion 12 and the sheet portion 13.

  The piston 3 has a boss portion 3d formed in an annular shape on the inner peripheral side and a seat portion 3e formed in an annular shape on the outer peripheral side in order to stack the pressure-side leaf valve 5 on the other end which is the one chamber R1 side end. And has an annular groove 3c between the boss 3d and the seat 3e.

  As shown, the leaf valves 4 and 5 on each side are formed by stacking a plurality of annular leaf valves (not shown) each having the same diameter, and further, annular leaf valves (not shown) having different diameters. ) Are stacked, and are fixed to the piston 3 so that the outer peripheral end is fixed and the outer peripheral end is free.

  The leaf valves 4 and 5 on each side are interposed in the tip 2a of the rod 2 so as to sandwich the piston 3 from above and below, and the inner peripheral ends are seated on the bosses 12 and 3d of the piston 3. In this state, the stepped portion 2b of the rod 2 and the tip thread portion 2c of the rod 2 are clamped and fixed between the screwed piston nut 6, and the outer peripheral side end portions are seated on the seat portions 13 and 3e so as to be separably seated. Thus, the downstream ends of the ports 3a and 3b on each side are closed so as to be openable.

  Incidentally, the pressure-side leaf valve 5 is formed by laminating a plurality of sheets having the same diameter and a plurality of sheets having different diameters, but instead of this, it is composed of only a plurality of sheets having the same diameter. As a matter of course, a plurality of sheets having different diameters may not be stacked, and instead of a plurality of sheets having the same diameter, a single sheet may be used.

  Therefore, in the hydraulic shock absorber, when the piston 3 moves in the cylinder 1 and, for example, the one chamber R1 becomes narrow, the hydraulic oil from the one chamber R1 becomes the outer peripheral side end of the leaf valve 4 on the expansion side. The portion is bent, passes through a gap appearing between the sheet portion 13 and the other chamber R2 and flows out into the other chamber R2, and a predetermined damping action is performed by the pressure loss at this time.

  Contrary to the above, when the other chamber R2 is narrowed, the hydraulic oil from the other chamber R2 bends the outer peripheral side end portion of the pressure side leaf valve 5 and passes through the gap that appears between the seat portion 3e. On the other hand, it flows out to the chamber R1, and a predetermined damping action is performed by the pressure loss at this time.

  As described above, in the hydraulic shock absorber, the piston 3 is laminated with the leaf valve 4 on the extension side at one end. However, as shown in FIG. The height position H2 of the outer edge b of the seat portion 13 is higher than the height position H1 of the inner edge a on the outer side of one end, that is, on the other chamber R2 side. It has a difference in height.

  In FIG. 2, for convenience of explanation, it is assumed that the leaf valve 4 is composed of one sheet indicated by a two-dot chain diagram, and the reference numeral 3 f in FIG. 2 is provided on the shaft core portion of the piston 3. The hole which accept | permits the penetration of the front-end | tip part 2a of the rod 2 is shown.

  As described above, when the seat 3 has a height difference with respect to the boss portion 12 at one end of the piston 3, the leaf valve 4 is laminated at the one end, and the inner peripheral side end portion is provided. At the time of fixing to the boss portion 12, the outer peripheral side end portion is pressed against the upper end of the sheet portion 13, and an initial load can be applied.

  Therefore, the pressure loss due to the leaf valve 4, that is, the hydraulic oil from one chamber R1 deflects the outer peripheral side end of the leaf valve 4 and passes through the gap that appears between the seat portion 13 and flows out into the other chamber R2. As a result, the pressure loss is larger than when the initial load is not applied to the leaf valve 4, and a high damping force can be generated.

  Incidentally, although not shown, it goes without saying that even at the other end of the piston 3 on which the pressure-side leaf valve 5 is laminated, there may be a height difference that makes the seat portion 3e higher than the boss portion 3d.

  Next, one end of the piston 3 is shown in the figure, and the surface from the inner edge a of the boss portion 12 to the outer edge b of the seat portion 13 is the left side in FIG. It is said that they are on the same curved surface that gradually increases toward the outside of the piston 3 on the right side.

  Since the surface between the inner peripheral edge a of the boss portion 12 and the outer edge b of the seat portion 13 is on the same curved surface that gradually increases from the inside toward the outside at one end of the piston 3, The boss portion 12 is almost in a horizontal plane.

  The surface between the outer edge c of the boss portion 12 and the outer edge b of the seat portion 13 is on the same curved surface that gradually increases from the inside toward the outside at one end of the piston 3. Thus, when the leaf valve 4 is stacked on one end of the piston 3, the inner peripheral side end fixed to the boss portion 12 and the portion 4a outside the outer edge c of the boss portion 12 are locally connected to the connection portion 4b. General deformation is not expressed.

  That is, as described above, in the conventional example shown in FIG. 3, the height difference between the boss part P1 and the sheet part P2 is embodied by the conical surface formed by the boss part P1 and the sheet part P2. In the leaf valve V to be laminated, local deformation occurs in the connection portion V2 between the inner peripheral side end portion laminated on the boss portion P1 and the portion V1 outside the outer edge P3 of the boss portion P1. .

  On the other hand, in the present invention, as shown in FIG. 2, since the boss portion 12 that fixes the inner peripheral side end of the leaf valve 4 is close to a horizontal plane, the inner peripheral side end of the leaf valve 4 is When fixing to the boss portion 12, local deformation is not expressed in the connecting portion 4 b between the inner peripheral side end portion of the leaf valve 4 and the portion 4 a outside the outer edge c of the boss portion 12.

  And when the leaf valve 4 laminated | stacked on one end is seen as a whole, the same curved surface which becomes high gradually toward the outside from the inner side to the outer side between the inner edge a of the boss part 12 and the outer edge b of the seat part 13 Since it exists in the upper part, the leaf valve 4 will be in the continuous natural deformation state from the boss | hub part 12 to the sheet | seat part 13 without a local deformation | transformation.

  Accordingly, even if the force for fixing the inner peripheral side end of the leaf valve 4 to the boss portion 12 varies, or there is a dimensional error in the height or outer diameter of the boss portion 12, the above connected portion The amount of deformation at 4b does not increase, and the initial load applied to the outer peripheral side end of the leaf valve 4 can be prevented from being divided, and a damping force is generated as set in the hydraulic shock absorber. This makes it possible to stabilize the ride feeling and eliminate variations, and improve the reproducibility of the ride feeling.

  As described above, at one end of the piston 3, the continuous surface from the inner edge a of the boss portion 12 to the outer edge b of the seat portion 12 is on the same curved surface that gradually increases from the inner side toward the outer side. Alternatively, although not shown, they may be on the same circular arc surface that gradually increases from the inside toward the outside. Incidentally, the arc surface is a surface that bends with the same curvature, but the curved surface is a surface that bends without making the curvature the same, and includes a surface formed of a quadratic curve and a surface that forms an ellipse.

  Even when the continuous surface from the inner edge a of the boss portion 12 to the outer edge b of the seat portion 13 is on the same circular arc surface that gradually increases from the inner side toward the outer side, the boss portion 12 is extremely horizontal. It becomes a nearly horizontal plane, and it becomes possible to prevent the above-described local deformation in the connecting portion 4b.

  From this point of view, the boss portion 12 may be formed of a horizontal plane (not shown) instead of being on the same curved surface or the same circular arc surface as described above. 12 between the outer edge c of the sheet 12 and the outer edge b of the sheet portion 13 is on the same curved surface or the same arc surface that gradually increases from the inside toward the outside. It is possible to prevent local deformation from occurring in the connecting portion 4b between the inner peripheral side end portion of the leaf valve 4 and the outer peripheral portion 4a. Incidentally, although not shown, the sheet portion 13 may be formed of a horizontal plane instead of the same curved surface or the same arc surface.

  In the above description, the case where the partition body is the piston 3 inserted into the cylinder 1 has been described as an example. However, from the intention of the present invention, the partition body is provided in the cylinder 1 although not illustrated. It may be a leaf valve disk in the base leaf valve.

  And in the place mentioned above, although it was supposed that the annular groove 11 which is a recessed part between the boss | hub part 12 and the sheet | seat part 13 was formed in the end of piston 3, from a viewpoint of implementation of this invention, it replaces with this Although not shown in the drawings, the concave portion may be composed of a stand-alone opening window defined by a boss portion 12 and a sheet portion 13 and a connecting portion that connects the boss portion 12 and the sheet portion 13 on the left and right. In this case, the upper surface of the connecting portion is included in the same curved surface or the same arc surface between the inner edge c of the boss portion 12 and the outer edge b of the seat portion 13.

  Further, in the illustrated case, the hydraulic shock absorber is set to be an inverted type, but it is needless to say that the present invention can be realized even if the hydraulic shock absorber is set to an upright type. .

DESCRIPTION OF SYMBOLS 1 Cylinder 2 Rod 2a Tip part 2b Step part 2c Tip thread part 3 Piston 3a, 3b Port 3c, 11 Annular groove 3d, 12 Boss part 3e, 13 Seat part 3f Hole 4, 5 Leaf valve 4a Outside Part 4b Connection part 5a Through hole 6 Piston nut a Inner edge b, c Outer edge H1, H2 Height position R1 One chamber as pressure chamber R2 Other chamber as pressure chamber

Claims (2)

A partition body for partitioning the pressure chamber, a leaf valve stacked on the partition body, a boss for fixing the inner peripheral end of the leaf valve, and an outer peripheral end of the leaf valve are seated A shock absorber having a height difference that makes the sheet portion higher than the boss portion between the boss portion and the sheet portion.
The space between the outer edge of the boss portion and the outer edge of the sheet portion is on the same curved surface or the same arc surface that gradually increases from the inner side to the outer side of the partition body,
The shock absorber according to claim 1, wherein the boss portion is on the curved surface or the arc surface, or is a horizontal surface. A recess is provided between the sheet portion and the boss portion,
The concave portion includes an opening window defined by the boss portion, the sheet portion, and a connecting portion that connects the boss portion and the sheet portion.
The shock absorber according to claim 1, wherein the curved surface or the circular arc surface includes the connecting portion.

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