JP2009024752A - Hydraulic shock absorber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydraulic shock absorber which can suppress a variation of damping force accompanying a temperature variation of hydraulic fluid. <P>SOLUTION: The absorber comprises: a valve disk 2 defining the inside of a cylinder enclosed with the hydraulic fluid; a port 6a communicating with oil chambers 3 and 4 defined by the valve disk 2; relief valves 12 and 13 which are arranged by closing the port 6a, and open by being bent when a pressure difference between the oil chambers 3 and 4 exceeds a predetermined value; and spacers 11 and 14 which are arranged by contacting with ends of the relief valves 12 and 13, and regulate bending fulcrum points of the relief valves 12 and 13. Furthermore, the spacers 11 and 14 change the fulcrum points of the relief valves 12 and 13 by radially telescoping in connection with temperature variation, and compensate a variation of damping force accompanying the temperature variation of the hydraulic fluid. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a hydraulic shock absorber.

As a hydraulic shock absorber mounted on a vehicle such as an automobile, a piston that defines a cylinder with two oil chambers, a port that is provided in the piston and that communicates with the two oil chambers, and a port that can be opened and closed are provided. In addition, a device including a leaf valve is known (see, for example, Patent Document 1).
JP 2004-190716 A

  In this type of hydraulic shock absorber, when the temperature of the hydraulic oil rises, the damping force generated tends to decrease because the viscosity of the hydraulic oil decreases. Further, when the temperature of the hydraulic oil is lowered, the viscosity of the hydraulic oil is increased, so that the generated damping force tends to increase.

  As described above, when the temperature of the hydraulic oil changes, the viscosity of the hydraulic oil changes accordingly, so that the damping force generated by the hydraulic shock absorber changes. Therefore, a desired damping force characteristic may not be obtained depending on the temperature change.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a hydraulic shock absorber that can suppress a change in damping force accompanying a change in temperature of hydraulic oil.

  The present invention provides a valve disk defining a cylinder filled with hydraulic oil, a port formed in the valve disk and communicating between oil chambers defined by the valve disk, and closing the port. A leaf valve that bends and opens when the pressure difference between the upstream oil chamber and the downstream oil chamber exceeds a predetermined value, and is disposed in contact with the end of the leaf valve, And a spacer for defining a fulcrum of the leaf valve, and the spacer changes the fulcrum of the leaf valve by expanding and contracting in the radial direction in accordance with a change in temperature. It is characterized by compensating for changes in force.

  According to the present invention, since the bending characteristics of the leaf valve change due to the expansion and contraction of the spacer in the radial direction accompanying the temperature change, it is possible to suppress the change in the damping force accompanying the temperature change of the hydraulic oil.

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

(First embodiment)
A hydraulic shock absorber 100 according to a first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a cross-sectional view of the hydraulic shock absorber 100.

  The hydraulic shock absorber 100 is interposed between a vehicle body and an axle in a vehicle such as an automobile, and has a function of suppressing a change in vehicle body posture.

  The hydraulic shock absorber 100 includes a cylindrical cylinder 1 in which hydraulic oil is sealed, a piston 2 that is slidably inserted into the cylinder 1 and defines the two oil chambers 3 and 4 in the cylinder 1, and one end. The piston 2 is fixed, and the other end includes a rod 5 extending to the outside of the cylinder 1. In the present embodiment, the piston 2 corresponds to the valve disk.

  A gas chamber (not shown) is provided in the cylinder 1 to compensate for volume changes in the cylinder 1 due to the entry and exit of the rod 5.

  The piston 2 has a cylindrical core portion 2a through which the rod 5 is inserted, and an annular ring portion 2b that slides with the inner periphery of the cylinder 1 via a band 8 attached to the outer periphery. The ring portion 2b is formed to have a larger axial dimension than the core portion 2a. As a result, the piston 2 is formed with an accommodating portion 2c surrounded by the ring portion 2b.

  The piston 2 is formed with a plurality of inner peripheral ports 6 a that always communicate with the rod-side oil chamber 3 and a plurality of outer peripheral ports 6 b that always communicate with the oil chamber 4 on the opposite rod side. The hydraulic oil in the cylinder 1 moves back and forth between the oil chamber 3 and the oil chamber 4 via the inner peripheral port 6a and the outer peripheral port 6b. Specifically, the inner peripheral port 6 a is a flow path that guides hydraulic oil in the oil chamber 3 to the oil chamber 4 when the hydraulic shock absorber 100 is extended, and the outer peripheral port 6 b is when the hydraulic shock absorber 100 is compressed. This is a flow path for guiding the hydraulic oil in the oil chamber 4 to the oil chamber 3.

  An annular groove 2d in which hydraulic oil flowing out from the plurality of inner peripheral ports 6a joins is formed at the outlet of the inner peripheral port 6a in the piston 2, and a plurality of outer peripheral ports 6b are formed at the outlet of the outer peripheral port 6b. An annular groove 2e is formed in which the hydraulic oil that has flowed out of the tank joins.

  The band 8 is made of resin, and the piston 2 slides along the inner periphery of the cylinder 1 via the band 8, so that wear of the inner periphery of the cylinder 1 is suppressed, and the inner periphery of the cylinder 1 and the outer periphery of the piston 2 are The passage of hydraulic oil between the two is prevented and good sealing performance is obtained.

  The rod 5 has a rod main body portion 5a that slides relative to the cylinder 1 via a bearing (not shown), and an inlay portion 5b that is formed on the distal end side and has a smaller diameter than the rod main body portion 5a. Each member including the piston 2 is assembled to the inlay portion 5b.

  The member assembled | attached to the inlay part 5b is demonstrated.

  A step portion 5c is formed at the boundary between the rod main body portion 5a and the spigot portion 5b in the rod 5, and an annular valve stopper 10 is locked to the step portion 5c. The valve stopper 10 is formed with a plurality of through holes 10a through which hydraulic oil passes.

  The valve stopper 10 is disposed in contact with the inner peripheral side of the laminated leaf valve 12 via an annular spacer 11, and the piston 2 is disposed in contact with the laminated leaf valve 12.

  A laminated leaf valve 13 is accommodated in the accommodating portion 2c of the piston 2 in contact with the core portion 2a, and a male screw portion 5d at the tip of the inlay portion 5b is disposed on the inner peripheral side of the laminated leaf valve 13 via an annular spacer 14. A nut 15 that is screwed into the abutment is disposed in contact therewith.

  As described above, the valve stopper 10, the spacer 11, the laminated leaf valve 12, the piston 2, the laminated leaf valve 13, the spacer 14, and the nut 15 are sequentially inserted into the inlay part 5 b, and each of these members is inserted. Is fixed to the spigot part 5 b by tightening the nut 15.

  The laminated leaf valves 12 and 13 are configured by laminating a plurality of annular leaf valves, and bend and open when the pressure difference between the upstream oil chamber and the downstream oil chamber exceeds a predetermined value. It is. In the present embodiment, the laminated leaf valves 12 and 13 are described as being formed by laminating a plurality of leaf valves. However, the number of leaf valves to be laminated is determined by the required damping force, and the leaf valves are determined. It is also possible to configure with only one leaf valve without stacking.

  The laminated leaf valve 12 is arranged such that the inner peripheral side is supported between the spacer 11 and the piston 2, and the free end side, which is the outer peripheral side, is seated on the seat portion 21 of the piston 2 and the outer peripheral port 6b is closed. . Therefore, when the hydraulic shock absorber 100 is compressed and the pressure in the oil chamber 4 rises and the pressure difference between the oil chamber 3 and the oil chamber 4 exceeds a predetermined value, the outer diameter portion of the spacer 11 is used as a fulcrum. The outer peripheral side bends and opens. Thereby, a gap is generated between the laminated leaf valve 12 and the seat portion 21, and a damping force is generated by the flow resistance generated when the hydraulic oil passes through the gap. Thus, the laminated leaf valve 12 is a damping valve for the compression stroke.

  Similarly, the laminated leaf valve 13 is supported on the inner peripheral side between the spacer 14 and the piston 2, and the free end side, which is the outer peripheral side, is seated on the seat portion 22 of the piston 2 to close the inner peripheral port 6a. Arranged. Therefore, when the hydraulic shock absorber 100 is extended and the pressure in the oil chamber 3 increases and the pressure difference between the oil chamber 3 and the oil chamber 4 exceeds a predetermined value, the outer diameter portion of the spacer 14 is used as a fulcrum. The outer peripheral side bends and opens. Thus, the laminated leaf valve 13 is a damping valve for the extension stroke. The laminated leaf valve 12 is formed with a through passage 16 for guiding hydraulic oil to the inner peripheral port 6a, and the inlet passage of the inner peripheral port 6a is connected to the through passage 16 and the inner peripheral port 6a. An annular groove 2 f is formed, and the inner peripheral port 6 a is always in communication with the oil chamber 3 through the annular groove 2 f and the through passage 16.

  As described above, the laminated leaf valves 12 and 13 are supported by the spacers 11 and 14 on the opposite free end side which is the inner peripheral side, and the free end side which is the outer peripheral side is supported by the outer diameter portion of the spacers 11 and 14 as a fulcrum. The valve opens by bending.

  The spacers 11 and 14 will be described in detail below. In the following description, the spacer 11 that supports the laminated leaf valve 12 for the compression stroke will be described as an example.

  The spacer 11 is disposed so that its inner periphery fits snugly with the outer periphery of the spigot part 5b and abuts against the end of the laminated leaf valve 12 on the side opposite to the free end, and the laminated leaf valve 12 is formed at the outer diameter portion thereof. This defines the fulcrum of bending.

  Deformation of the portion of the laminated leaf valve 12 supported by the spacer 11 and the piston 2 is restricted. Therefore, the larger the outer diameter of the spacer 11, the larger the support diameter, which is the fulcrum of bending in the laminated leaf valve 12, and the shorter the distance from the end of the spacer 11 to the free end of the laminated leaf valve 12, The laminated leaf valve 12 becomes difficult to bend. Further, the smaller the outer diameter of the spacer 11, the smaller the support diameter in the laminated leaf valve 12, and the longer the distance from the end of the spacer 11 to the free end of the laminated leaf valve 12, the laminated leaf valve 12 It becomes easy to bend.

  Therefore, the damping force generated by the hydraulic shock absorber 100 is greatly influenced by the outer diameter portion of the spacer 11, that is, the radial dimension.

  The spacer 11 is made of a material having a large linear expansion coefficient. Therefore, the spacer 11 expands and contracts in the radial direction as the temperature changes, and changes the support diameter of the laminated leaf valve 12. As a result, the damping force generated by the hydraulic shock absorber 100 changes as the temperature changes.

  Generally, when the temperature of the hydraulic oil is high, the viscosity of the hydraulic oil decreases and the generated damping force tends to decrease. When the temperature of the hydraulic oil is low, the viscosity of the hydraulic oil increases and is generated. The damping force to be increased tends to increase.

  In this way, when the temperature of the hydraulic oil changes, the damping force generated by the hydraulic shock absorber 100 also changes accordingly. However, since the spacer 11 expands and contracts in the radial direction as the temperature changes and changes the support diameter of the laminated leaf valve 12, it acts to compensate for the change in damping force that accompanies the temperature change.

  Specifically, the linear expansion coefficient of the spacer 11 is set larger than the linear expansion coefficient of the piston 2. More specifically, the linear expansion coefficient of the spacer 11 is set so that the expansion / contraction amount of the spacer 11 in the radial direction accompanying the temperature change is larger than the expansion / contraction amount of the piston 2 in the radial direction. The

  By setting the linear expansion coefficient of the spacer 11 in this way, the support diameter supported by the spacer 11 and the piston 2 in the laminated leaf valve 12 changes with temperature change. Thus, the spacer 11 is deformed relative to the piston 2 in the radial direction so as to compensate for the change in the damping force accompanying the temperature change.

  Next, the effect | action of the spacer 11 accompanying a temperature change is demonstrated.

  When the temperature of the hydraulic oil rises, the spacer 11 expands in the radial direction, so that the support diameter of the laminated leaf valve 12 is displaced toward the free end side and becomes large. Thereby, the free end side of the laminated leaf valve 12 becomes difficult to bend.

  As described above, when the temperature of the hydraulic oil rises, the damping force generated tends to decrease because the viscosity of the hydraulic oil decreases, but the spacer 11 acts to make the laminated leaf valve 12 difficult to bend. This makes it difficult for hydraulic oil to pass between the laminated leaf valve 12 and the seat portion 21. Therefore, the decrease in the damping force due to the decrease in the viscosity of the hydraulic oil is compensated by the expansion of the spacer 11 in the radial direction.

  Further, when the temperature of the hydraulic oil decreases, the spacer 11 contracts in the radial direction, so that the support diameter of the laminated leaf valve 12 is displaced toward the non-free end side and becomes smaller. Thereby, the free end side of the laminated leaf valve 12 is easily bent.

  As described above, when the temperature of the hydraulic oil decreases, the damping force generated tends to increase because the viscosity of the hydraulic oil increases. However, the spacer 11 acts to make the laminated leaf valve 12 easily bent. Therefore, the hydraulic oil easily passes between the laminated leaf valve 12 and the seat portion 21. Therefore, an increase in damping force due to an increase in the viscosity of the hydraulic oil is suppressed by the contraction of the spacer 11 in the radial direction.

  As described above, the spacer 11 expands and contracts in the radial direction as the temperature changes, and changes the support diameter of the laminated leaf valve 12, and acts to compensate for the change in damping force accompanying the temperature change. To do.

  As another aspect of the present embodiment, the spacer 11 may be made of a shape memory alloy. In this case, the spacer 11 is made of a bi-directional shape memory alloy that expands in the axial direction when it rises above the reference temperature (transformation point) and contracts in the axial direction when it falls below the reference temperature. By configuring the spacer 11 in this way, the spacer 11 expands and contracts in the radial direction as the temperature changes, and acts so as to compensate for the change in the damping force accompanying the temperature change.

  According to the above embodiment, the following operational effects are obtained.

  The spacer 11 is made of a material having a large linear expansion coefficient. Therefore, when the temperature of the hydraulic oil rises, the spacer 11 expands in the radial direction, so that the support diameter of the laminated leaf valve 12 increases. Thereby, the generated damping force is increased, and the decrease in the damping force due to the decrease in the viscosity of the hydraulic oil is compensated. Further, when the temperature of the hydraulic oil is lowered, the spacer 11 contracts in the radial direction, so that the support diameter of the laminated leaf valve 12 is reduced. Thereby, the generated damping force is reduced, and an increase in the damping force due to an increase in the viscosity of the hydraulic oil is suppressed.

  As described above, since the bending characteristics of the laminated leaf valve 12 change due to the expansion and contraction of the spacer 11 in the radial direction accompanying the temperature change, the change in the damping force accompanying the temperature change of the hydraulic oil can be suppressed, and the operation Even when the temperature change of the oil is large, a desired damping force characteristic can be obtained.

  In the above description, the spacer 11 that supports the laminated leaf valve 12 for the compression stroke has been described. However, the spacer 14 that supports the laminated leaf valve 13 for the extension stroke also has the same configuration and has the same effects. Play.

(Second Embodiment)
A hydraulic shock absorber 200 according to a second embodiment of the present invention will be described with reference to FIG. FIG. 2 is a cross-sectional view of the hydraulic shock absorber 200. In the following description, the same reference numerals as those used in the first embodiment refer to the same members as those described in the first embodiment.

  The hydraulic shock absorber 200 according to the second embodiment generates a damping force by the base valve 30 that is fixedly disposed on the bottom of the cylinder 1.

  The base valve 30 is disposed in the oil chamber 4, and the outer peripheral edge is press-fitted into the end of the cylinder 1 to be fixed to the bottom of the cylinder 1, and the oil chamber 29 is defined at the bottom of the cylinder 1. In the present embodiment, the base valve 30 corresponds to a valve disk.

  The oil chamber 29 communicates with a tank chamber 33 defined by the outer periphery of the cylinder 1 and the inner periphery of the outer cylinder 32 via a notch passage 30 a formed at the end of the base valve 30.

  A gas chamber (not shown) is provided in the tank chamber 33 to compensate for volume changes in the cylinder 1 due to the entry and exit of the rod 5.

  The base valve 30 is formed with a plurality of inner peripheral ports 34 a that always communicate with the oil chamber 4 and a plurality of outer peripheral ports 34 b that always communicate with the tank chamber 33. The inner peripheral port 34 a is a flow path that guides the hydraulic oil in the oil chamber 4 to the tank chamber 33 during the compression operation of the hydraulic shock absorber 100, and the outer peripheral port 34 b is the operation of the tank chamber 33 during the expansion operation of the hydraulic shock absorber 100. This is a flow path for guiding oil to the oil chamber 4.

  A guide member 31 to which each member is assembled is inserted into a through hole formed in the shaft center of the base valve 30.

  The guide member 31 includes a rod portion 31a through which the base valve 30 is inserted, a large-diameter portion 31b having a larger diameter than that of the rod portion 31a, and a flange portion 31c having a larger diameter than that of the large-diameter portion 31b. .

  A member assembled to the guide member 31 will be described.

  The large-diameter portion 31 b includes a non-return valve 36 disposed in contact with the base valve 30 with the outer peripheral port 34 b closed, and a non-return spring 37 that biases the non-return valve 36 against the base valve 30. Is inserted. A through passage 36a for guiding hydraulic oil to the inner peripheral port 34a is formed on the inner peripheral side of the non-return valve 36. The inner peripheral port 34a is always in communication with the oil chamber 4 through the through passage 36a. Yes.

  In the rod portion 31a, the base valve 30 is disposed in contact with a step portion 31d formed at the boundary with the large diameter portion 31b. A laminated leaf valve 38 is superimposed on the base valve 30 with the inner peripheral port 34a closed. A valve stopper 40 is disposed in contact with the inner peripheral side of the laminated leaf valve 38 via a spacer 39. As described above, the laminated leaf valve 38 is supported between the base valve 30 and the spacer 39 on the inner peripheral side, and the free end side, which is the outer peripheral side, closes the inner peripheral port 34a. Is.

  Thus, the laminated leaf valve 38, the spacer 39, and the valve stopper 40 are fitted into the rod portion 31a, and the caulking portion 42 provided at the end portion of the rod portion 31a is caulked against the valve stopper 40. As a result, each member is fixed to the guide member 31.

  When the hydraulic shock absorber 200 is compressed to increase the pressure in the oil chamber 4 and the pressure difference between the oil chamber 4 and the oil chamber 29 exceeds a predetermined value, the laminated leaf valve 38 bends and opens on the outer peripheral side. . As a result, a gap is generated between the laminated leaf valve 38 and the seat portion 30 b of the base valve 30, and hydraulic oil corresponding to the volume of entry of the rod 5 is discharged from the oil chamber 4 to the tank chamber 33 through the oil chamber 29. . A damping force is generated by the flow resistance generated when the hydraulic oil passes between the laminated leaf valve 38 and the seat portion 30b. Thus, the laminated leaf valve 38 is a damping valve for the compression stroke.

  When the hydraulic shock absorber 200 is extended, the hydraulic oil passes through the outer peripheral port 34 b and pushes the non-return valve 36 against the urging force of the non-return spring 37. As a result, the hydraulic oil corresponding to the withdrawal volume of the rod 5 flows into the oil chamber 4 from the tank chamber 33 through the oil chamber 29.

  In this way, the laminated leaf valve 38 is supported by the spacer 39 on the non-free end side which is the inner peripheral side, and the free end side which is the outer peripheral side is bent and opened with the outer diameter portion of the spacer 39 as a fulcrum. It is.

  Also in the present embodiment, the damping force generated by the hydraulic shock absorber 100 is greatly affected by the outer diameter portion of the spacer 39, that is, the radial dimension.

  As in the first embodiment, the spacer 39 is disposed so that its inner periphery fits closely with the outer periphery of the rod portion 31a and is in contact with the end of the laminated leaf valve 38 on the non-free end side. The fulcrum of deflection of the laminated leaf valve 38 is defined by the outer diameter portion.

  Also in the present embodiment, the spacer 39 is made of a material having a large linear expansion coefficient. Specifically, the linear expansion coefficient of the spacer 39 is set larger than the linear expansion coefficient of the base valve 30. More specifically, the linear expansion coefficient of the spacer 39 is set so that the expansion / contraction amount in the radial direction of the spacer 39 accompanying the temperature change is larger than the expansion / contraction amount in the radial direction of the base valve 30. Is done.

  By setting the linear expansion coefficient of the spacer 39 in this way, the support diameter supported by the spacer 39 and the base valve 30 in the laminated leaf valve 38 changes with a temperature change. Thus, the spacer 39 is deformed relative to the base valve 30 in the radial direction so as to compensate for the change in the damping force accompanying the temperature change.

  Also in the second embodiment described above, as in the first embodiment, the spacer 39 expands and contracts in the radial direction as the temperature changes, and changes the support diameter of the laminated leaf valve 38. Yes, it acts to compensate for temperature changes in damping force accompanying temperature changes.

  The present invention is not limited to the above-described embodiment, and it is obvious that various modifications can be made within the scope of the technical idea.

  The present invention can be applied to a shock absorber mounted on a vehicle.

It is sectional drawing which shows the hydraulic shock absorber 100 in embodiment of this invention. It is sectional drawing which shows the hydraulic shock absorber 200 in embodiment of this invention.

Explanation of symbols

100, 200 Hydraulic shock absorber 1 Cylinder 2 Piston 3, 4 Oil chamber 5 Rod 6a Inner peripheral port 6b Outer peripheral port 10 Valve stopper 11, 14 Spacer 12, 13 Laminated leaf valve 30 Bale valve 31 Guide member 31a Rod portion 33 Tank chamber 34a Inner peripheral port 34b Outer peripheral port 38 Laminated leaf valve 39 Spacer

Claims (4)

A valve disk defining a cylinder filled with hydraulic oil;
A port formed in the valve disc and communicating between oil chambers defined by the valve disc;
A leaf valve that is disposed with the port closed, and bends and opens when the pressure difference between the upstream oil chamber and the downstream oil chamber exceeds a predetermined value;
A spacer that is disposed in contact with the end of the leaf valve and that defines a fulcrum of deflection of the leaf valve;
The said spacer is a hydraulic shock absorber characterized by changing the fulcrum of bending of the said leaf valve by expanding-contracting to a radial direction with a temperature change, and compensating the change of the damping force accompanying the temperature change of hydraulic fluid.   The hydraulic shock absorber according to claim 1, wherein a linear expansion coefficient of the spacer is larger than a linear expansion coefficient of the valve disk.   The linear expansion coefficient of the spacer is set such that the amount of expansion / contraction in the radial direction of the spacer accompanying a change in temperature is larger than the amount of expansion / contraction in the radial direction of the valve disc. The hydraulic shock absorber according to claim 2.   2. The hydraulic shock absorber according to claim 1, wherein the spacer is made of a shape memory alloy and compensates for a change in damping force accompanying a temperature change of the hydraulic oil by expanding and contracting in a radial direction with a temperature change. vessel.

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