JP4839060B2 - Damping force generation valve structure of hydraulic shock absorber - Google Patents

Description

  The present invention relates to a hydraulic shock absorber used in a suspension device of a vehicle such as an automobile, and more particularly to a damping force generation valve structure using a leaf valve provided in a piston portion thereof.

  A hydraulic shock absorber used in a suspension device of a vehicle such as an automobile has a piston portion or a base valve for appropriately reducing vibration transmitted from the road surface to the vehicle body during traveling and improving riding comfort and operability. A valve structure for generating a damping force is provided in the part.

  As the specific structure, various types can be exemplified, but as a general structure provided in the piston portion, for example, a damping force generation valve structure of a hydraulic shock absorber shown in Patent Document 1 is exemplified. Can do.

  That is, as shown in FIG. 3, the piston rod 1 is composed of a rod main body and a columnar mounting portion 2 that extends while being reduced in diameter at the base end of the rod main body. , An upper spacer 4, a compression side damping force generation valve 6 composed of a plurality of compression side leaf valves 5, a piston body 9 having compression side and expansion side ports 7, 8, and an extension side damping force generation composed of a plurality of extension side leaf valves 10. The valve 11, the lower spacer 12, and the valve stopper 13 are sequentially inserted and stacked through a mounting hole formed in the center thereof, and the nut 14 is screwed from below the mounting portion 2 to form the above. Each member below the valve stopper 3 is sandwiched between the base end portion 2a of the mounting portion 2 and the nut 14.

  In the valve structure of the hydraulic shock absorber configured as described above, the hydraulic oil in the piston-side oil chamber P that has passed through the compression-side port 7 by the compression operation of the piston rod 1 is the compression-side leaf valve that constitutes the compression-side damping force generation valve 6. By bending the outer peripheral side of 5 and flowing into the rod side chamber R, a compression side damping force is generated.

Further, the hydraulic oil in the rod side chamber R that has passed through the expansion side port 8 by the extension operation of the piston rod 1 deflects the outer peripheral side of the expansion side leaf valve 10 constituting the expansion side damping force generation valve 11 and flows into the piston side chamber P. By doing so, the damping force on the extension side is generated.
Japanese Patent Laid-Open No. 11-1912943 (FIG. 4)

  The damping force generation valve structure of the hydraulic shock absorber configured as described above is not particularly problematic, but there may be the following problems.

  That is, in recent years, vehicles equipped with this type of hydraulic shock absorber have come to require various damping force characteristics depending on the type and application, and when setting damping force characteristics according to the demand, For example, the shape, plate thickness, number of the expansion side or compression side leaf valves 10 and 5 constituting the expansion side or compression side damping force generation valves 11 and 6 can be changed, or the expansion side or compression side damping force generation valves 10 and 5 can be changed. The sheet surface shape of the stretch side or pressure side ports 8 and 7 serving as the pressure receiving surface is changed.

  However, among the above changes, changing the shape, thickness, and number of the extension side or compression side leaf valves 10 and 5 can be implemented at a relatively low cost. There is a limit to increasing the degree of freedom in setting the damping force.

  Also, changing the seat surface shape in addition to the change of the leaf valve makes it possible to change the pressure receiving surface, so that the degree of freedom in setting the damping force can be increased by that amount. However, there are a plurality of types of piston bodies 9 that are different from each other, which increases the manufacturing cost and complicates parts management.

  Accordingly, the present invention is to provide a valve structure of a hydraulic shock absorber that has a simple structure and allows a large degree of freedom in setting damping force.

In order to achieve the above object, the means of the present invention comprises a solid piston rod comprising a rod body and a mounting portion extending while reducing the diameter from the base end of the rod body, and the pressure side with respect to this mounting portion. A damping force generation valve, a piston body having only two types of ports , a compression side and an extension side port , and an extension side damping force generation valve composed of a plurality of leaf valves are sequentially inserted through the central mounting hole and stacked. The nut is screwed from the tip of the mounting portion, and the compression side damping generation valve, the piston body and the extension side damping force generation valve are sandwiched between the nut and the base end of the rod body , A compression-side annular groove that communicates with the compression-side port and an expansion-side recess that communicates with the expansion-side port are formed, and an expansion-side damping force is applied to the lower central sheet surface formed between the compression-side annular groove and the expansion-side recess. generation valve is brought into contact In the damping force generation valve structure of the pressure buffer, at least the portion of the mounting portion from which the extension side damping force generation valve is inserted is formed as a small diameter mounting portion having a smaller diameter than the base end side, and the extension portion is also combined. The inner diameter of the mounting hole of the side damping force generating valve is formed corresponding to the outer diameter of the small diameter mounting portion, and the inner diameter of the mounting hole of the piston body is formed corresponding to the outer diameter of the mounting portion. To do.

  According to the present invention, since the inner diameter of the mounting hole of the expansion side damping force generation valve is formed corresponding to the outer diameter of the small diameter mounting part, the expansion side damping force generation valve is connected to the small diameter mounting part via this mounting hole. Can be inserted.

  In addition, the inner diameter of this mounting hole can be set smaller than the inner diameter of the mounting hole of the conventional expansion side damping force generating valve inserted into the mounting portion, so that the difference in diameter between the mounting portion and the small diameter mounting portion can be set smaller. The difference between the inner and outer diameters of the leaf valve main body constituting the side damping force generating valve can be made larger than that of the conventional leaf valve, in other words, the leaf valve main body can be lengthened.

Accordingly, the leaf valve can be easily bent, and by adjusting the dimension of the difference in diameter as desired, the adjustment range can be increased and the degree of freedom in setting the damping force can be increased.
In addition, the inner diameter of the mounting hole of the expansion side damping force generating valve is formed corresponding to the outer diameter of the small-diameter mounting portion, and the inner diameter of the mounting hole of the piston body is formed corresponding to the outer diameter of the mounting portion, The lateral force applied to the piston body in the operating state of the shock absorber can be received by the large-diameter mounting portion, and there is no lack of strength.

  Hereinafter, an embodiment in which the present invention is embodied in a damping force generation valve structure provided in a piston portion of a single cylinder type hydraulic shock absorber used in an automobile suspension device will be described with reference to the drawings.

  The basic structure of the damping force generating valve structure of the present invention is composed of a piston rod 1 and a mounting portion 2 extending while reducing the diameter from the base end of the rod body. A generation valve 6, a piston body 9 having a compression side port 7 and an expansion side port 8, and an expansion side damping force generation valve 11 composed of a plurality of leaf valves 10 are sequentially inserted and laminated through the mounting holes in the center, A hydraulic shock absorber in which a nut 14 is screwed from the distal end of the mounting portion 2 and the compression side damping generation valve 6, the piston body 9, and the extension side damping force generation valve 11 are sandwiched between the nut 14 and the base end of the rod body. This is a damping force generating valve structure.

  In the present invention, the distal end side of at least the portion of the mounting portion 2 into which the expansion side damping force generating valve 11 is inserted is formed as a small diameter mounting portion 2c having a smaller diameter than the base end side. The inner diameter of the mounting hole of the force generating valve 11 is formed corresponding to the outer diameter of the small diameter mounting portion 2c.

  In the embodiment of FIG. 1, a valve stopper 3, an upper spacer 4, a compression-side damping force generation valve 6, and a plurality of compression sides with respect to the reduced-diameter mounting portion 2 provided at the proximal end of the rod body of the piston rod 1. The piston body 9, the collar body 16, the extension side damping force generating valve 11 and the lower spacer 12 having the extension side ports 7 and 8 are sequentially inserted through the center attachment hole and stacked. A nut 14 is screwed onto the tip from below the portion 2, and each member below the valve stopper 3 is clamped between the lower end of the rod body and the nut 14 and fixed while tightening.

  More specifically, the back side of the piston body 9 is formed with an extension side annular groove 19 that communicates a plurality of extension side ports 8 and a pressure side annular groove 20 that also communicates a plurality of compression side ports 7. An upper inner sheet surface 21 is formed between the expansion-side annular groove 19 and the central mounting hole 9a, and an upper center-side sheet surface 22 is formed between the expansion-side annular groove 19 and the compression-side annular groove 20, and the compression side An upper outer sheet surface 23 is formed on the outer peripheral side of the annular groove 20.

  The compression side damping force generation valve 6 is configured by laminating two compression side leaf valves 5, and the inner peripheral end is fixed by being sandwiched between the upper inner seat surface 21 and the upper spacer 4. The upper side seat surface 22 and the upper outer seat surface 23 that are the open ends of the pressure side port 7 in this state are in contact with each other, and the pressure side port 7 is closed so as to be opened and closed.

  A communication hole 5a is formed in a portion of the two pressure side leaf valves 5 facing the expansion side port 8, and hydraulic oil from the stopper side communication hole 3a provided in the valve stopper 3 passes through the communication hole 5a. It passes through the extending side port 8 without resistance.

  Note that a plurality of notches 5b are provided in the portion facing the pressure side port 7 of the pressure side leaf valve 5 in contact with the upper center side and the outer seat surfaces 22, 23, and the notch portion 5b has a small piston speed. A damping force is generated in the low speed range.

  The lower surface, which is the inner surface facing the piston-side oil chamber P in the piston body 9, has a conical frusto-conical extending side recess 24 communicating with the plurality of extending side ports 8, and a pressure side annular groove communicating with the plurality of pressure side ports 7. 25, and a lower center side sheet surface 26 is formed between the extension-side recess 24 and the pressure-side annular groove 25.

  The mounting portion 2 is formed in a cylindrical shape whose diameter is slightly reduced from the base end side with respect to the portion facing the extended-side annular recess 24 via the inclined portion 2b, thereby forming the small-diameter mounting portion 2c of the present invention. In addition, a screw portion 2d for screwing the nut 14 is formed on the outer periphery of the tip.

  An annular collar body 16 having an L-shaped cross section is inserted into the small-diameter mounting portion 2c through the insertion hole. The lower surface constitutes a lower inner seat surface 27 on the lower surface of the piston body 9 while abutting.

  The extension side damping force generation valve 11 is formed by stacking five extension side leaf valves 10, and the inner peripheral end is fixed by being sandwiched between the collar body 16 and the lower spacer 12. In this state, the abutment is brought into contact with the central seat surface 26 serving as the opening end of the expansion side port 8, and the expansion side port 8 is closed so as to be openable and closable.

  Further, since the extension-side leaf valve 10 is inserted into the small-diameter mounting portion 2c, only the difference in diameter between the mounting portion 2 and the small-diameter mounting portion 2c (hereinafter referred to as a small-diameter portion r) is inserted into the mounting portion 2. Compared to the conventional leaf valve 10 shown in FIG. 3, the mounting hole 10b has a smaller inner diameter, and accordingly, the inner and outer diameter differences are made larger than the conventional leaf valve 10 to make it easier to bend. By arbitrarily selecting the outer diameter of the portion 2c and the inner diameter of the mounting hole 10b, the degree of freedom in setting the damping force can be increased.

  Note that a plurality of notches 10a are provided in a portion facing the extension side port 8 of the extension side leaf valve 10 in contact with the lower center side seat surface 26, and the notch 10a provides a piston speed in a very low speed range. A damping force is generated.

  The damping force generating valve structure configured as described above is slidably housed in the cylinder 29, so that the piston body 9 causes the inside of the cylinder 29 to be divided into a rod-side oil chamber R and a piston-side oil chamber P. It is defined.

  Therefore, in the extension stroke in which the piston body 9 moves upward in the cylinder 29, the hydraulic oil that has passed through the extension side port 8 extends in the extension side damping force generation valve 11 in the very low speed range of the piston speed. By passing through the notch 10a provided on the side leaf valve 10, a damping force that becomes an orifice characteristic is generated, and at the high speed range of the piston speed, the expansion side leaf valve 10 itself is bent to generate a damping force that becomes a valve characteristic. Let

  Further, in the pressure side stroke in which the piston body 9 moves downward in the cylinder 29, the hydraulic oil that has passed through the pressure side port 7 is the pressure side leaf valve 5 that constitutes the pressure side damping force generation valve 6 in the very low speed range of the piston speed. By passing through the notch portion 5b provided in, a damping force that becomes an orifice characteristic is generated, and in the high speed region of the piston speed, the compression side leaf valve 5 itself is bent to generate a damping force that becomes a valve characteristic.

  In the damping force generating valve structure configured as described above, the diameter of the mounting portion 2 is reduced from the base end side slightly below the portion facing the expansion-side concave portion 24 of the piston body 9 via the inclined portion 2b. By doing so, the small-diameter mounting portion 2c of the present invention is formed, so that the diameter of the mounting hole 10b of the extension-side leaf valve 10 that is inserted into the small-diameter mounting portion 2c can be reduced by the small diameter r.

  Accordingly, the inner / outer diameter difference can be made larger than that of the conventional leaf valve, and as described above, the degree of freedom in setting the damping force can be increased.

  Further, since the small-diameter mounting portion 2c is formed below the portion that is slightly proximal to the portion facing the expansion side recess 24 of the piston body 9, the lateral force applied to the piston body 9 in the operating state of the hydraulic shock absorber is reduced. It can be received by the large-diameter mounting portion 2 and does not cause insufficient strength.

  Further, since the small diameter mounting portion 2c is continuously extended with respect to the mounting portion 2 via the inclined portion 2b, it is possible to prevent stress from being concentrated on the boundary portion between the mounting portion 2 and the small diameter mounting portion 2c. However, this portion can also be used as a right-angle step.

  Further, since the annular collar body 16 having an L-shaped cross section is inserted into the small-diameter mounting portion 2c, and the lower inner seat surface 27 on the lower surface of the piston body 9 is formed on the lower surface of the collar body 16, only the shape of the seat surface is formed. It is possible to arbitrarily change the pressure receiving area of the extension side damping force generation valve 11 by only changing the diameter of the collar body 16 without having a plurality of types of piston bodies 9 different from each other.

  Therefore, in this damping force generation valve structure, in addition to the difference between the inner and outer diameters of the extension side leaf valve 10 described above, the pressure receiving area can be easily changed, so the degree of freedom in setting the damping force can be further increased. .

  In addition, this invention is not limited to the said embodiment, For example, it can also be changed as follows.

  1) In the present embodiment, the collar body 16 is inserted into the small-diameter mounting portion 2c, and the lower inner sheet surface 27 on the lower surface of the piston body 9 is formed on the lower surface thereof. However, the present invention is not limited to this. As shown in FIG. 4, the collar body 16 may be omitted by integrally forming the annular protrusion 31 serving as the lower inner sheet surface on the piston body 9.

  2) In the present embodiment, the collar body 16 is inserted into the small-diameter mounting portion 2c, and the lower inner sheet surface 27 on the lower surface of the piston body 9 is formed on the lower surface thereof. However, the present invention is not limited to this. The initial load may be applied to the extension side damping force generating valve 11 by increasing the thickness of the vertical direction 16.

  Further, the portion into which the collar body 16 is inserted is not necessarily the small-diameter mounting portion 2c as in this embodiment, and may be the mounting portion 2 having a larger diameter than the small-diameter mounting portion 2c.

  3) In the present embodiment, the small-diameter mounting portion 2c is formed below the portion that is slightly proximal to the portion facing the extended recess 24 of the piston body 9. However, the present invention is not limited to this. It is good also considering the downward direction from the attaching part 2 used as the part in which the expansion side damping force generation | occurrence | production valve | bulb 11 is inserted as the small diameter attaching part 2c.

  4) In the present embodiment, the inclined portion 2b is provided between the attachment portion 2 and the small-diameter attachment portion 2c. However, the present invention is not limited to this, and the material constituting the attachment portion 2 and the small-diameter attachment portion 2c is used. In the case of sufficient strength, the inclined portion 2b is not necessary.

  5) In the present embodiment, the damping force generating valve structure used for the piston portion of the single cylinder type hydraulic shock absorber is embodied, but the present invention is not limited to this, and the piston portion of the double cylinder type hydraulic shock absorber is not limited thereto. The damping force generation valve structure to be used may be embodied.

FIG. 4 is a cross-sectional view of the main part showing the best embodiment of the present invention and showing the right side of the center line of the damping force generating valve structure used for the piston of the single cylinder type hydraulic shock absorber. FIG. 5 is a cross-sectional view of a principal part showing another example of the present invention and showing the right side from the center line of the damping force generating valve structure used for the piston of the single cylinder type hydraulic shock absorber as in FIG. It is principal part sectional drawing which shows the damping force generation | occurrence | production valve | bulb structure which shows the prior art example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Piston rod 2 Mounting part 2a Base end part of mounting part 2b Inclined part 2c Small diameter mounting part 6 Pressure side damping force generation valve 7 Pressure side port 8 Stretch side port 9 Piston body 9a Piston body mounting hole 10 Stretch side leaf valve 10a Stretch side Leaf valve mounting hole 11 Extension side damping force generation valve 14 Nut 16 Collar body 27 Lower inner peripheral seat surface r Small diameter

Claims (3)

A solid piston rod is composed of a rod body and a mounting part extending while reducing the diameter from the base end of the rod body. Two types of pressure side damping force generating valve, pressure side and extension side port are provided for this mounting part. A piston body having only a port and an extension side damping force generating valve composed of a plurality of leaf valves are sequentially inserted and stacked through a mounting hole in the center, and a nut is screwed from the tip of the mounting portion to The compression side damping generation valve, the piston body, and the extension side damping force generation valve are sandwiched between the nut and the base end of the rod body , the pressure side annular groove communicating with the pressure side port on the side surface of the nut of the piston body, the extension side port, A damping force generating valve structure for a hydraulic shock absorber , in which an extending side recess is formed, and the extending side damping force generating valve is in contact with a lower central seat surface formed between the compression side annular groove and the extending side recess. In The tip side of the mounting part from which at least the extension side damping force generating valve is inserted is formed as a small diameter mounting part having a smaller diameter than the base end side, and the inner diameter of the mounting hole of the extension side damping force generating valve is also set. A damping force generating valve structure for a hydraulic shock absorber, which is formed corresponding to the outer diameter of the small-diameter mounting portion, and the inner diameter of the mounting hole of the piston body is formed corresponding to the outer diameter of the mounting portion. The damping force generation valve structure for a hydraulic shock absorber according to claim 1, wherein an inclined portion is provided between the attachment portion and the small diameter attachment portion. The collar body is inserted into the mounting portion or the small-diameter mounting portion via the mounting hole between the lower surface of the piston body and the upper surface of the expansion side damping force generation valve, and the lower surface of the collar body is inserted into the extension side damping force generation valve. The damping force generation valve structure for a hydraulic shock absorber according to claim 1 or 2, constituting an inner seat surface.

Images